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  • REVIEW
    Anudurga Gajendiran, Jayanthi Abraham
    Frontiers in Biology, 2018, 13(2): 79-90. https://doi.org/10.1007/s11515-018-1489-z

    BACKGROUND: Pesticides are used to control various pests of agricultural crops worldwide. Despite their agricultural benefits, pesticides are often considered a serious threat to the environment because of their persistence. Pyrethroids are synthetic derivates of pyrethrins, which are natural organic insecticides procured from the flowers of Chrysanthemum cinerariaefolium and C. coccineum. Pyrethroids are classified into two groups—class I and class II—based on their toxicity and physical properties. These pyrethroids are now used in many synthetic insecticides and are highly specific against insects; they are generally used against mosquitoes. The prominent site of insecticidal action of pyrethroids is the voltage-sensitive sodium channels.

    METHODS and RESULTS: Pyrethroids are found to be stable, and they persist in the environment for a long period. This article provides an overview of the different classes, structure, and insecticidal properties of pyrethroid. Furthermore, the toxicity of pyrethroids is also discussed with emphasis on bioremediation to alleviate pollution.

    CONCLUSIONS: The article focuses on various microorganisms used in the degradation of pyrethroids, the molecular basis of degradation, and the role of carboxylesterase enzymes and genes in the detoxification of pyrethroid.

  • REVIEW
    Gabrielle Rushing,Rebecca A. Ihrie
    Frontiers in Biology, 2016, 11(4): 261-284. https://doi.org/10.1007/s11515-016-1407-1

    BACKGROUND: The origin and classification of neural stem cells (NSCs) has been a subject of intense investigation for the past two decades. Efforts to categorize NSCs based on their location, function and expression have established that these cells are a heterogeneous pool in both the embryonic and adult brain. The discovery and additional characterization of adult NSCs has introduced the possibility of using these cells as a source for neuronal and glial replacement following injury or disease. To understand how one could manipulate NSC developmental programs for therapeutic use, additional work is needed to elucidate how NSCs are programmed and how signals during development are interpreted to determine cell fate.

    OBJECTIVE: This review describes the identification, classification and characterization of NSCs within the large neurogenic niche of the ventricular-subventricular zone (V-SVZ).

    METHODS: A literature search was conducted using Pubmed including the keywords “ventricular-subventricular zone,” “neural stem cell,” “heterogeneity,” “identity” and/or “single cell” to find relevant manuscripts to include within the review. A special focus was placed on more recent findings using single-cell level analyses on neural stem cells within their niche(s).

    RESULTS: This review discusses over 20 research articles detailing findings on V-SVZ NSC heterogeneity, over 25 articles describing fate determinants of NSCs, and focuses on 8 recent publications using distinct single-cell analyses of neural stem cells including flow cytometry and RNA-seq. Additionally, over 60 manuscripts highlighting the markers expressed on cells within the NSC lineage are included in a chart divided by cell type.

    CONCLUSIONS: Investigation of NSC heterogeneity and fate decisions is ongoing. Thus far, much research has been conducted in mice however, findings in human and other mammalian species are also discussed here. Implications of NSC heterogeneity established in the embryo for the properties of NSCs in the adult brain are explored, including how these cells may be redirected after injury or genetic manipulation.

  • REVIEW
    John VU, John CARVALHO
    Frontiers in Biology, 2011, 6(5): 357-366. https://doi.org/10.1007/s11515-011-1167-x

    The genus Enterococcus is composed of 38 species, the most important of which are Enterococcus faecalis and Enterococcus faecium—both human intestinal colonizers. Hospitals within the United States and around the world commonly isolate these bacteria because they are a cause of bacteremia, urinary tract infections (UTIs), endocarditis, wound infections, meningitis, intraabdominal and pelvic infections, and nosocomial and iatrogenic infections. Given the ubiquity of enterococci within the human population, it is important for laboratories to be able to distinguish these agents within hospitalized patients from other bacterial genera and also differentiate different species within the Enterococcus genus as well as different strains within each species. Unfortunately, the enterococci are emerging as serious pathogens in both the developed world, where surveillance needs to be improved and speciation procedures are inadequate or cumbersome, and in developing nations, which lack the trained hospital personnel or funding to sufficiently identify enterococci to the genus or species level. This review explores the Enterococcus genus and highlights some of the concerns for national and international clinical microbiology laboratories.

  • RESEARCH ARTICLE
    Yanping Ding,Shiyuan Yu,Baoping Shao
    Frontiers in Biology, 2016, 11(2): 141-148. https://doi.org/10.1007/s11515-016-1393-3

    This study presents the first definitive anatomical description of the tongue and lingual papillae of the cattle-yak. Data on tongues from 12 healthy cattle-yaks were collected. The results show that five types of papillae were identifiable on the tongue surface of the cattle-yak. Among these, three types were mechanical papillae (filiform, conical, and lenticular), and two types were gustatory papillae (vallate and fungiform). Some morphological features of the cattle-yak tongue were similar to those of domestic ruminants, but the lingual prominence was higher and more developed. For example, more mechanical papillae were present and they were covered by a thicker, keratinized epithelium, the conical papillae possibly perform an immune function, the fungiform papillae have more mucus-secreting pores, and the sublingual glands were more developed. This research will provide a further and detailed source of morphological information about the cattle-yak that is currently lacking in species-specific studies on the morphology of the Bovidae family.

  • RESEARCH ARTICLE
    Gregory W. Kirschen, Hanxiao Liu, Tracy Lang, Xuelin Liang, Shaoyu Ge, Qiaojie Xiong
    Frontiers in Biology, 2017, 12(2): 124-138. https://doi.org/10.1007/s11515-017-1447-1

    BACKGROUND: Neuronal primary cilia are sensory organelles that are critically involved in the proper growth, development, and function of the central nervous system (CNS). Recent work also suggests that they signal in the context of CNS injury, and that abnormal ciliary signaling may be implicated in neurological diseases.

    METHODS: We quantified the distribution of neuronal primary cilia alignment throughout the normal adult mouse brain by immunohistochemical staining for the primary cilia marker adenylyl cyclase III (ACIII) and measuring the angles of primary cilia with respect to global and local coordinate planes. We then introduced two different models of acute brain insult—temporal lobe seizure and cerebral ischemia, and re-examined neuronal primary cilia distribution, as well as ciliary lengths and the proportion of neurons harboring cilia.

    RESULTS: Under basal conditions, cortical cilia align themselves radially with respect to the cortical surface, while cilia in the dentate gyrus align themselves radially with respect to the granule cell layer. Cilia of neurons in the striatum and thalamus, by contrast, exhibit a wide distribution of ciliary arrangements. In both cases of acute brain insult, primary cilia alignment was significantly disrupted in a region-specific manner, with areas affected by the insult preferentially disrupted. Further, the two models promoted differential effects on ciliary lengths, while only the ischemia model decreased the proportion of ciliated cells.

    CONCLUSIONS:These findings provide evidence for the regional anatomical organization of neuronal primary cilia in the adult brain and suggest that various brain insults may disrupt this organization.

  • LI Qi, LIANG Wenju, OU Wei
    Frontiers in Biology, 2008, 3(4): 518-524. https://doi.org/10.1007/s11515-008-0063-5
    An analysis of the seasonal and vertical distribution of soil nematode communities under three contrasting land uses, i.e., cropland, abandoned cropland and woodland was conducted in an aquic brown soil. The results showed that different land-use types affected the spatiotemporal distribution of soil nematodes and their dominant genera, and different dominant genera showed different responses to land use. In the abandoned cropland and woodland, most dominant genera were present in the 0–20 cm layers and Chiloplacus was mainly distributed in the 5–30 cm layers, while in the cropland, Pratylenchus exhibited an even distribution from the 0–5 cm to the 40–50 cm depth. Soil environmental parameters under different land use could influence soil nematodes; soil porosity, total organic C, total N and the C/N ratio could positively influence the abundance of some dominant genera. Faunal profiles revealed that environmental stability and the homeostasis in the abandoned cropland and woodland lead to higher levels of community structure, and the soil food web tends to succeed to maturity. Nematode faunal analyses are a useful indicator for interpreting the stress and/or nutrient conditions under different land uses.
  • Yan Enrong, Wang Xihua, Huang Jianjun
    Frontiers in Biology, 2006, 1(1): 76-84. https://doi.org/10.1007/s11515-005-0019-y
    Coarse woody debris (CWD) is generally considered as dead woody materials in various stages of decomposition, including sound and rotting logs, snags, and large branches. CWD is an important functional and structural component of forested ecosystems and plays an important role in nutrient cycling, long-term carbon storage, tree regeneration, and maintenance of heterogeneous environmental and biological diversity. However, the definition and classification of CWD have been the subject of a long debate in forest ecology. CWD has not been precisely defined. Recently, with the rapid development of landscape ecology in CWD, the USDA Forest Service and the Long Term Ecological Research (LTER) have provided a standardized definition and classification for CWD, which makes data comparison in landscape scale possible. Important characteristics of their definition include: (1) a minimum diameter (or an equivalent crosssection) of CWD "e10 cm at the widest point (the woody debris with a diameter from 1 to 10 cm should be defined as fine woody debris, and the rest is litterfall); and (2) sound and rotting logs, snags, stumps, and large branches (located above the soil), and coarse root debris (larger than 1 cm in diameter). This classification has greatly facilitated CWD studies. Therefore, it has been widely applied in some countries (particularly in North America). However, this classification has long been a source of confusion for forest ecologists in China. Furthermore, different definitions and criteria are still adopted in individual studies, which makes the interpretation and generalization of their work difficult. This article reviewed recent progress in classifying CWD, with an emphasis on introducing the classification system of the USDA Forest Service and the LTER. It is expected that this review will help facilitate the development of standardized definition and classification suitable to forest ecosystems in China.
  • REVIEW
    Young-Cho Kim,Stephanie L. Alberico,Eric Emmons,Nandakumar S. Narayanan
    Frontiers in Biology, 2015, 10(3): 230-238. https://doi.org/10.1007/s11515-015-1360-4

    The neurotransmitter dopamine acts via two major classes of receptors, D1-type and D2-type. D1 receptors are highly expressed in the striatum and can also be found in the cerebral cortex. Here we review the role of D1 dopamine signaling in two major domains: L-DOPA-induced dyskinesias in Parkinson’s disease and cognition in neuropsychiatric disorders. While there are many drugs targeting D2-type receptors, there are no drugs that specifically target D1 receptors. It has been difficult to use selective D1-receptor agonists for clinical applications due to issues with bioavailability, binding affinity, pharmacological kinetics, and side effects. We propose potential therapies that selectively modulate D1 dopamine signaling by targeting second messengers downstream of D1 receptors, allosteric modulators, or by making targeted modifications to D1-receptor machinery. The development of therapies specific to D1-receptor signaling could be a new frontier in the treatment of neurological and psychiatric disorders.

  • REVIEW
    Nidhi VISHNOI,Jie YAO
    Frontiers in Biology, 2014, 9(4): 255-268. https://doi.org/10.1007/s11515-014-1313-3

    The eukaryotic genome is packaged as chromatin within the three-dimensional nuclear space. Decades of cytological studies have revealed that chromosomes and genes are non-randomly localized within the nucleus and such organizations have important roles on genome function. However, several fundamental questions remain to be resolved. For example, what is required for the preferential localization of a gene to a nuclear landmark? What is the mechanism underlying gene repositioning in the nucleus? How does subnuclear gene positioning regulate gene transcription? Recent studies have revealed that several factors such as DNA sequence composition, specific regulatory sequences, epigenetic modifications, chromatin remodelers, post-transcriptional regulators and nuclear architectural proteins can influence chromatin dynamics and gene positioning in a gene-specific manner among organisms from yeast to human. In this review, we discuss some recent findings as well as experimental tools to investigate subnuclear gene positioning and to explore its implications in genome functions.

  • RESEARCH ARTICLE
    Xin-Min Qin,Qing-Xin Guan,Hui-Min Li,Yu Zhang,Yu-Ji Liu,Dan-Ni Guo
    Frontiers in Biology, 2015, 10(5): 458-472. https://doi.org/10.1007/s11515-015-1371-1

    The complete mitochondrial genome sequence of Lamproptera curia was determined in the present study. Our findings showed that the mtDNA of L. curia had a typical organization of insect mitochrondrial DNA − being 15277 base pairs in length, it contained 13 protein-coding genes (PCGs), 2 rRNA genes, 22 tRNA genes, and a control region(CR). The newly determined sequence was used for phylogenetic analyses, together with those of 45 species of Lepidoptera published elsewhere, including sequences of three species of Diptera as outgroups. The phylogenetic trees were constructed using the concatenated amino acid and nucleotide sequences of the 13 protein-coding genes (PCGs) based on the maximum likelihood (ML) and Bayesian inference (BI) methods. Both BI and ML trees revealed a similar topology structure: (((((Bombycoidea+ Geometroidea) + Noctuoide) + Pyraloidea) + (Papilionoidea+ Hesperioidea)) + Tortricoidea). Furthermore, the phylogenetic analyses demonstrated that each of the 16 families belonged to a monophyletic group respectively. The results of molecular phylogeny from the present study were congruent with traditional classification based on morphology but failed to demonstrate the monophyly of Hesperiidae.

  • REVIEW
    Afsar U. AHMED
    Frontiers in Biology, 2011, 6(4): 274-281. https://doi.org/10.1007/s11515-011-1123-9

    Inflammation is an essential response provided by the immune systems that ensures the survival during infection and tissue injury. Inflammatory responses are essential for the maintenance of normal tissue homeostasis. The molecular mechanism of inflammation is quite a complicated process which is initiated by the recognition of specific molecular patterns associated with either infection or tissue injury. The entire process of the inflammatory response is mediated by several key regulators involved in the selective expression of proinflammatory molecules. Prolonged inflammations are often associated with severe detrimental side effects on health. Alterations in inflammatory responses due to persistent inducers or genetic variations are on the rise over the last couple of decades, causing a variety of inflammatory diseases and pathophysiological conditions.

  • ZHANG Yufen, ZHANG Dayong
    Frontiers in Biology, 2007, 2(3): 256-262. https://doi.org/10.1007/s11515-007-0036-0
    Most plants can reproduce both sexually and asexually (or vegetatively), and the balance between the two reproductive modes may vary widely between and within species. Extensive clonal growth may affect the evolution of life history traits in many ways. First, in some clonal species, sexual reproduction and sex ratio vary largely among populations. Variation in sexual reproduction may strongly affect plant’s adaptation to local environments and the evolution of the geographic range. Second, clonal growth can increase floral display, and thus pollinator attraction, while it may impose serious constraints and evolutionary challenges on plants through geitonogamy that may strongly influence pollen dispersal. Geitonogamous pollination can bring a cost to plant fitness through both female and male functions. Some co-evolutionary interactions, therefore, may exist between the spatial structure and the mating behavior of clonal plants. Finally, a trade-off may exist between sexual reproduction and clonal growth. Resource allocation to the two reproductive modes may depend on environmental conditions, competitive dominance, life span, and genetic factors. If different reproductive modes represent adaptive strategies for plants in different environments, we expect that most of the resources should be allocated to sexual reproduction in habitats with fluctuating environmental conditions and strong competition, while clonal growth should be dominant in stable habitats. Yet we know little about the consequence of natural selection on the two reproductive modes and factors which control the balance of the two reproductive modes. Future studies should investigate the reproductive strategies of clonal plants simultaneously from both sexual and asexual perspectives.
  • REVIEW
    Yaojuan LU,Longwei QIAO,Guanghua LEI,Ranim R. MIRA,Junxia GU,Qiping ZHENG
    Frontiers in Biology, 2014, 9(3): 195-204. https://doi.org/10.1007/s11515-014-1310-6

    The type X collagen gene, COL10A1, is specifically expressed by hypertrophic chondrocytes during endochondral ossification. Endochondral ossification is a well-coordinated process that involves a cartilage intermediate and leads to formation of most of the skeleton in vertebrates during skeletogenesis. Chondrocyte hypertrophy is a critical stage of endochondral ossification linking both bone and cartilage development. Given its specific association with chondrocyte hypertrophy, type X collagen plays essential roles in endochondral ossification. It was previously shown that transgenic mice with mutant type X collagen develop variable skeleton-hematopoietic abnormalities indicating defective endochondral ossification, while mutations and abnormal expression of human COL10A1 cause abnormal chondrocyte hypertrophy that has been seen in many skeletal disorders, including skeletal chondrodysplasia and osteoarthritis. In this review, we summarized the skeletal chondrodysplasia with COL10A1 gene mutation that shows growth plate defect. We also reviewed recent studies that correlate the type X collagen gene expression and chondrocyte hypertrophy with osteoarthritis. Due to its significant clinical relevance, the type X collagen gene regulation has been extensively studied over the past two decades. Here, we focus on recent progress characterizing the cis-enhancer elements and their binding factors that together confer hypertrophic chondrocyte-specific murine type X collagen gene (Col10a1) expression. Based on literature review and our own studies, we surmise that there are multiple factors that contribute to hypertrophic chondrocyte-specific Col10a1 expression. These factors include both transactivators (such as Runx2, MEF2C etc.) and repressors (such as AP1, NFATc1, Sox9 etc.), while other co-factors or epigenetic control of Col10a1 expression may not be excluded.

  • RESEARCH ARTICLE
    C. Subathra DEVI, Renuka ELIZABETH JOSEPH, Harini SARAVANAN, S. Jemimah NAINE, V. Mohana SRINIVANSAN
    Frontiers in Biology, 2013, 8(6): 632-639. https://doi.org/10.1007/s11515-013-1284-9

    The current work was attempted to isolate and characterize the serratiopeptidase producing Serratia sp. Among the 10 bacterial isolates 7 strains were identified as Serratia sp. Out of 7 strains one showed potent proteolytic activity and selected for further studies. Based on the morphological, biochemical and molecular characterization, the potent isolate (RH03) was identified as Serratia marcescens (GenBank accession number: KC961637) and the strain was designated as Serratia marcescens VITSD2. The production of serratiopeptidase was carried out in trypticase soya broth and the enzyme was partially purified using ammonium sulfate precipitation and dialysis. The specific activity was determined by casein hydrolysis assay and was found to be 12.00, 21.33, and 25.40 units/mg for crude, precipitated and dialysed samples. The molecular weight of the protease was determined by SDS-PAGE and it was found to be 50 kDa. The antibacterial activity of the produced serratiopeptidase showed moderate activity against Pseudomonas aeruginosa MTCC No. 4676 (12 mm) and Escherichia coli MTCC No. 1588 (15 mm).

  • REVIEW
    Yunsong LAI, Huanxiu LI, Masumi YAMAGISHI
    Frontiers in Biology, 2013, 8(6): 577-598. https://doi.org/10.1007/s11515-013-1281-z

    Flavonoid biosynthetic genes are often coordinately regulated in a temporal manner during flower or fruit development, resulting in specific accumulation profiles of flavonoid compounds. R2R3-MYB-type transcription factors (TFs) “recruit” a set of biosynthetic genes to produce flavonoids, and, therefore, R2R3-MYBs are responsible for the coordinated expression of structural genes. Although a wealth of information regarding the identified and functionally characterized R2R3-MYBs that are involved in flavonoid accumulation is available to date, this is the first review on the global regulation of MYB factors in the flavonoid pathway. The data presented in this review demonstrate that anthocyanin, flavone/flavonol/3-deoxyflavonoid (FFD), proanthocyanidin (PA), and isoflavonoid are independently regulated by different subgroups of R2R3-MYBs. Furthermore, FFD-specific R2R3-MYBs have a preference for early biosynthetic genes (EBGs) as their target genes; anthocyanin-specific R2R3-MYBs from dicot species essentially regulate late biosynthetic genes (LBGs); the remaining R2R3-MYBs have a wider range of target gene specificity. To elucidate the nature of the differential target gene specificity between R2R3-MYBs, we analyzed the DNA binding domain (also termed the MYB-domain) of R2R3-MYBs and the distribution of the recognition cis-elements. We identified four conserved amino acid residues located in or just before helix-3 of dicot anthocyanin R2R3-MYBs that might account for the different recognition DNA sequence and subsequently the different target gene specificity to the remaining R2R3-MYB TFs.

  • REVIEW
    Colin G. SCANES, Eldon BRAUN
    Frontiers in Biology, 2013, 8(2): 134-159. https://doi.org/10.1007/s11515-012-1206-2

    This review discussed metabolism in poultry and wild birds with an emphasis on what remains to be elucidated. Circulating concentrations of glucose are much greater in both poultry and wild birds than in mammals which in turn are higher than in reptiles. The basis for this difference is unknown but does not appear to be related to the requirements of flight. Furthermore, birds exhibit a refractoriness to potential adverse effects of very high circulating concentrations of glucose. Again the basis of this is unclear. There is substantial information on the control of metabolism in poultry, although which hormones are exerting physiologic roles remains to be clarified. There is a tacit but unverified assumption that the control mechanisms are the same in wild birds and in poultry. Despite, significant research focus on metabolism in poultry and to a less extent wild birds, there is a dearth of studies determining metabolism in a quantitative manner.

  • CHEN Liding, FU Bojie, ZHAO Wenwu
    Frontiers in Biology, 2008, 3(2): 131-136. https://doi.org/10.1007/s11515-008-0026-x
    Exploring the relationships between landscape pattern and ecological processes is the key topic of landscape ecology, for which, a large number of indices as well as landscape pattern analysis model were developed. However, one problem faced by landscape ecologists is that it is hard to link the landscape indices with a specific ecological process. Linking landscape pattern and ecological processes has become a challenge for landscape ecologists. “Source” and “sink” are common concepts used in air pollution research, by which the movement direction and pattern of different pollutants in air can be clearly identified. In fact, for any ecological process, the research can be considered as a balance between the source and the sink in space. Thus, the concepts of “source” and “sink” could be implemented to the research of landscape pattern and ecological processes. In this paper, a theory of source-sink landscape was proposed, which include: (1) In the research of landscape pattern and ecological process, all landscape types can be divided into two groups, “source” landscape and “sink” landscape. “Source” landscape contributes positively to the ecological process, while “sink” landscape is unhelpful to the ecological process. (2) Both landscapes are recognized with regard to the specific ecological process. “Source” landscape in a target ecological process may change into a “sink” landscape as in another ecological process. Therefore, the ecological process should be determined before “source” or “sink” landscape were defined. (3) The key point to distinguish “source” landscape from “sink” landscape is to quantify the effect of landscape on ecological process. The positive effect is made by “source” landscape, and the negative effect by “sink” landscape. (4) For the same ecological process, the contribution of “source” landscapes may vary, and it is the same to the “sink” landscapes. It is required to determine the weight of each landscape type on ecological processes. (5) The source-sink principle can be applied to non-point source pollution control, biologic diversity protection, urban heat island effect mitigation, etc. However, the landscape evaluation models need to be calibrated respectively, because different ecological processes correspond with different source-sink landscapes and evaluation models for the different study areas. This theory is helpful to further study landscape pattern and ecological process, and offers a basis for new landscape index design.
  • REVIEW
    Nazmul H. A. Mamun,Ulrika Egertsdotter,Cyrus K. Aidun
    Frontiers in Biology, 2015, 10(2): 177-193. https://doi.org/10.1007/s11515-015-1355-1

    Plant cell culture in bioreactors is an enabling tool for large scale production of clonal elite plants in agriculture, horticulture, forestry, pharmaceutical sectors, and for biofuel production. Advantages of bioreactors for plant cell culture have resulted in various types of bioreactors differing in design, operating technologies, instrumentations, and construction of culture vessels. In this review, different types of bioreactors for clonal propagation of plants and secondary metabolites production are discussed. Mechanical and biochemical parameters associated with bioreactor design, such as aeration, flow rate, mixing, dissolved oxygen, composition of built-up gas in the headspace, and pH of the medium, are pivotal for cell morphology, growth, and development of cells within tissues, embryos, and organs. The differences in such parameters for different bioreactor designs are described here, and correlated to the plant materials that have been successfully cultured in different types of bioreactors.

  • WU Zhengyi, SUN Hang, ZHOU Zhekun, PENG Hua, LI Dezhu
    Frontiers in Biology, 2007, 2(2): 125-143. https://doi.org/10.1007/s11515-007-0020-8
    The present paper analyzed 239 endemic genera in 67 families in the flora of seed plants in China. The results showed that there are five families containing more than ten endemic genera, namely, Gesneriaceae (27), which hereafter refers to the number of endemic genera in China, Composite (20), Labiatae (12), Cruciferae (11), and Umbelliferae (10), 15 families with two endemic genera, and another 30 families with only one endemic genus. Four monotypic families (Ginkgoaceae, Davidiaceae, Eucommiaceae and Acanthochlamydaceae) are the most ancient, relict and characteristic in the flora of seed plants in China. Based on integrative data of systematics, fossil history, and morphological and molecular evidence of these genera, their origin, evolution and relationships were discussed. In gymnosperms, all endemic genera are relicts of the Arctic-Tertiary flora, having earlier evolutionary history, and can be traced back to the Cretaceous or to the Jurassic and even earlier. In angiosperms, the endemic genera are mostly relicts, and are represented in all lineages in the Eight-Class System of Classification of Angiosperms , and endemism can be found in almost every evolutionary stage of extant angiosperms. The relict genera once occupied huge areas in the northern hemisphere in the Tertiary or the late Cretaceous, while neo-endemism mostly originated in the late Tertiary. They came from Arctic-Tertiary, Paleo-tropical-Tertiary and Tethys-Tertiary florisitic elements, and the blend of the three elements with many genera of autochthonous origin. The endemism was formed when some dispersal routes such as the North Atlantic Land Bridge, and the Bering Bridge became discontinuous during the Tertiary, as well as the climate change and glaciations in the late Tertiary and the Quaternary. Therefore, the late Tertiary is the starting point of extant endemism of the flora in China.
  • REVIEW
    Vipul SHUKLA,Runqing LU
    Frontiers in Biology, 2014, 9(4): 269-282. https://doi.org/10.1007/s11515-014-1318-y

    Interferon regulatory factor 4 (IRF4) and IRF8 are critical regulators of immune system development and function. In B lymphocytes, IRF4 and IRF8 have been shown to control important events during their development and maturation including pre-B cell differentiation, induction of B cell tolerance pathways, marginal zone B cell development, germinal center reaction and plasma cell differentiation. Mechanistically, IRF4 and IRF8 are found to function redundantly to control certain stages of B cell development, but in other stages, they function nonredundantly to play distinct roles in B cell biology. In line with their essential roles in B cell development, deregulated expressions of IRF4 and IRF8 have been associated to the pathogenesis of several B cell malignancies and diseases. Recent studies have elucidated diverse transcriptional networks regulated by IRF4 and IRF8 at distinct B cell developmental stages and related malignancies. In this review we will discuss the recent advances for the roles of IRF4 and IRF8 during B cell development and associated diseases.

  • REVIEW
    Xin YANG, Fengyang DENG, Katrina M. RAMONELL
    Frontiers in Biology, 2012, 7(2): 155-166. https://doi.org/10.1007/s11515-011-1185-8

    Plants have evolved multiple layers of defense against various pathogens in the environment. Receptor-like kinases/proteins (RLKs/RLPs) are on the front lines of the battle between plants and pathogens since they are present at the plasma membrane and perceive signature molecules from either the invading pathogen or damaged plant tissue. With a few notable exceptions, most RLKs/RLPs are positive regulators of plant innate immunity. In this review, we summarize recently discovered RLKs/RLPs that are involved in plant defense responses against various classes of pathogens. We also describe what is currently known about the mechanisms of RLK-mediated initiation of signaling via protein-protein interactions and phosphorylation.

  • REVIEW
    Paul A. NAKATA
    Frontiers in Biology, 2012, 7(3): 254-266. https://doi.org/10.1007/s11515-012-1224-0

    Crystals of calcium oxalate have been observed among members from most taxonomic groups of photosynthetic organisms ranging from the smallest algae to the largest trees. The biological roles for calcium oxalate crystal formation in plant growth and development include high-capacity calcium regulation, protection against herbivory, and tolerance to heavy metals. Using a variety of experimental approaches researchers have begun to unravel the complex mechanisms controlling formation of this biomineral. Given the important roles for calcium oxalate formation in plant survival and the antinutrient and pathological impact on human health through its presence in plant foods, researchers are avidly seeking a more comprehensive understanding of how these crystals form. Such an understanding will be useful in efforts to design strategies aimed at improving the nutritional quality and production of plant foods.

  • REVIEW
    Chenglong Yu,Min Zhang,Xianan Qin,Xiaofeng Yang,Hyokeun Park
    Frontiers in Biology, 2016, 11(2): 109-118. https://doi.org/10.1007/s11515-016-1397-z

    Recent advances in fluorescence microscopy have provided researchers with powerful new tools to visualize cellular processes occurring in real time, giving researchers an unprecedented opportunity to address many biological questions that were previously inaccessible. With respect to neurobiology, these real-time imaging techniques have deepened our understanding of molecular and cellular processes, including the movement and dynamics of single proteins and organelles in living cells. In this review, we summarize recent advances in the field of real-time imaging of single synaptic vesicles in live neurons.

  • REVIEW
    Selvarajan Ethiraj, Shreya Gopinath
    Frontiers in Biology, 2017, 12(5): 333-348. https://doi.org/10.1007/s11515-017-1461-3

    BACKGROUND: Serrapeptase is a proteolytic enzyme with many favorable biological properties like anti-inflammatory, analgesic, anti-bacterial, fibrinolytic properties and hence, is widely used in clinical practice for the treatment of many diseases. Although Serrapeptase is widely used, there are very few published papers and the information available about the enzyme is very meagre. Hence this review article compiles all the information about this important enzyme Serrapeptase.

    METHODS: A literature search against various databases and search engines like PubMed, SpringerLink, Scopus etc. was performed.

    RESULTS: We gathered and highlight all the published information regarding the molecular aspects, properties, sources, production, purification, detection, optimizing yield, immobilization, clinical studies, pharmacology, interaction studies, formulation, dosage and safety of the enzyme Serrapeptase.

    CONCLUSION:Serrapeptase is used in many clinical studies against various diseases for its anti-inflammatory, fibrinolytic and analgesic effects. There is insufficient data regarding the safety of the enzyme as a health supplement. Data about the anti-atherosclerotic activity, safety, tolerability, efficacy and mechanism of action of the Serrapeptase are still required.

  • REVIEW
    Erin S McWhorter, Jennifer E Russ, Quinton A Winger, Gerrit J Bouma
    Frontiers in Biology, 2018, 13(5): 315-326. https://doi.org/10.1007/s11515-018-1517-z

    BACKGROUND: The placenta is recognized as an endocrine organ, largely due to its secretions of steroid hormones, including progesterone, androgens, and estrogens. Steroid hormones play an essential role in the progression of pregnancy, fetal development, and growth. Furthermore, steroids are necessary for establishment and maintenance of a normal pregnancy, preparing the endometrium for implantation, stimulating endometrial secretions, and regulating uterine blood flow, however the exact mechanism of sex steroid signaling through their receptors in placental function is unknown.

    OBJECTIVE: In this review, we will provide an overview of the current knowledge on sex steroid receptors in normal placental development, as well as evidence of abnormal signaling associated with placental dysfunction.

    METHODS: A systematic literature search was performed using the NCBI PubMed search engine, including the following key works: estrogen receptor, androgen receptor, placenta, placental development, cytotrophoblast, and differentiation.

    RESULTS: Of the over 700 articles that were returned, 125 studies focused on estrogen and androgen receptors in human placenta development and function during normal and abnormal pregnancy, as well as in rodents and ruminants placentae.

    CONCLUSION: Receptors for both estrogens and androgens have been localized within the mammalian placenta, but surprisingly little is known about their signaling in trophoblast cell differentiation and function. An emerging picture is developing in which estrogen receptors possibly play role in cytotrophoblast proliferation and extravillous trophoblast invasion, whereas androgen receptors are involved in syncytiotrophoblast differentiation and function.

  • ZHANG Yanwen, WANG Yong, GUO Youhao
    Frontiers in Biology, 2007, 2(4): 443-449. https://doi.org/10.1007/s11515-007-0068-5
    The relationship between plant and pollinator is considered as the mutualism because plant benefits from the pollinator’s transport of male gametes and pollinator benefits from plant’s reward. Nectar robbers are frequently described as cheaters in the plant-pollinator mutualism, because it is assumed that they obtain a reward (nectar) without providing a service (pollination). Nectar robbers are birds, insects, or other flower visitors that remove nectar from flowers through a hole pierced or bitten in the corolla. Nectar robbing represents a complex relationship between animals and plants. Whether plants benefit from the relationship is always a controversial issue in earlier studies. This paper is a review of the recent literatures on nectar robbing and attempts to acquire an expanded understanding of the ecological and evolutionary roles that robbers play. Understanding the effects of nectar robbers on the plants that they visited and other flower visitors is especially important when one considers the high rates of robbing that a plant population may experience and the high percentage of all flower visitors that nectar robbers make to some species. There are two standpoints in explaining why animals forage on flowers and steal nectar in an illegitimate behavior. One is that animals can only get food in illegitimate way because of the mismatch of the morphologies of animals’ mouthparts and floral structure. The other point of view argues that nectar robbing is a relatively more efficient, thus more energy-saving way for animals to get nectar from flowers. This is probably associated with the difficulty of changing attitudes that have been held for a long time. In the case of positive effect, the bodies of nectar robbers frequently touch the sex organs of plants during their visiting to the flowers and causing pollination. The neutral effect, nectar robbers’ behavior may destruct the corollas of flowers, but they neither touch the sex organs nor destroy the ovules. Their behavior does not affect the fruit sets or seed sets of the hosting plant. Besides the direct impacts on plants, nectar robbers may also have an indirect effect on the behavior of the legitimate pollinators. Under some circumstances, the change in pollinator behavior could result in improved reproductive fitness of plants through increased pollen flow and out-crossing.
  • REVIEW
    Jorge A. LARIOS, Maria-Paz MARZOLO
    Frontiers in Biology, 2012, 7(2): 113-143. https://doi.org/10.1007/s11515-011-1186-7

    Studies related to the functional and regulatory aspects of proteolytic processing are of interest to cell biologists, developmental biologists and investigators who work on human diseases. Much of what is known about this topic derives from the study of the proteolytic processing of the amyloid precursor protein (APP), which is involved in the pathology of Alzheimer’s disease, and of the Notch protein and its Delta ligand, which play roles during embryonic development and in biologic processes in the adult. The proteolytic processing of plasma membrane receptor proteins is under the control of different enzymes that are responsible for releasing the ectodomain into the extracellular environment, where it has the potential to function as a signaling molecule and/or regulate the availability of the receptor’s ligand. Following shedding of the ectodomain, the γ-secretase enzymatic complex cleaves the transmembrane domain and releases the cytoplasmic domain (ICD) of the receptor. The ICD can function in the cytoplasm and/or at the nucleus.

    Members of the low-density lipoprotein receptor (LDLR) family are endocytic-signaling proteins that perform a wide variety of physiologic functions during development and in the adult life. In addition these receptors have been implicated in a variety of diseases in adults. The prototypic receptor for this family of proteins is the LDLR itself. Besides their binding to apolipoproteins, these receptors bind many ligands that are destined for internalization and degradation. Some ligands have signaling properties. The proteolytic processing of certain members of the LDLR family not only controls receptor availability at the cell surface but also has functional consequences that amplify the spectrum of roles that these receptors perform. In addition, many complex regulatory mechanisms control the proteolytic processing of these receptors.

  • RESEARCH ARTICLE
    V. Mohanasrinivasan., A. Mohanapriya, Swaroop Potdar, Sourav Chatterji, Srinath Konne, Sweta Kumari, S. Merlyn Keziah., C. Subathra Devi
    Frontiers in Biology, 2017, 12(3): 219-225. https://doi.org/10.1007/s11515-017-1453-3

    BACKGROUND: Nattokinase (NK) is a serine protease enzyme of the subtilisin family. It exhibits a strong fibrinolytic activity. The fibrinolytic enzymes from? Bacillus ?sp. have attracted interest as thrombolytic agents because of their efficiency in the fibrinolytic process including plasmin activation.

    METHODS: In the present study, VIT garden soil was collected and subjected to isolation process in order to screen for the NK production. Screening for NK enzyme was performed by radial caseinolytic assay. The production of NK enzyme was done in two different production medium for comparative studies. The NK enzyme was purified by gel permeation chromatography. The activity of the purified NK was checked by clot lysis and casein digestion assay. To investigate the structural basis of NK and fibrinogen interaction and also to identify the best binding mode, molecular dynamics and docking studies were performed.

    RESULTS: Based on the morphological and biochemical characterization, the isolate was identified as Bacillus sp. The overall purification fold of NK was about 3 with the specific activity of 664U/mg and 9.9% yield. Homogeneity of the purified enzyme was analyzed and confirmed by the single band obtained in SDS-PAGE. Molecular weight of the purified protease was estimated as 25 kDa. Purified NK enzyme exhibited 97% of effective clot lysis activity. The NK was docked in to the knob region of the fibrinogen at its binding site using Dock server. A total of 26 residues of fibrinogen and 29 residues of NK constitute the interface region. However, 9 residues of fibrinogen (THR238, MET264, LYS266, ARG275, THR277, ALA279, ASN308, MET310, and LYS321) and 8 residues of NK (GLY61, SER63, THR99, PHE189, LEU209, TYR217, ASN218, and MET222) are involved in intact binding.

    CONCLUSIONS: A significant amount of NK enzyme was obtained from Bacillus sp. The docking analysis revealed that the NK and fibrinogen adopt an extended binding pattern and interacts with the crucial residues to exhibit their activity.

  • RESEARCH ARTICLE
    Bharti Chaudhary, Sonam Agarwal, Renu Bist
    Frontiers in Biology, 2018, 13(1): 56-62. https://doi.org/10.1007/s11515-018-1479-1

    BACKGROUND: The present study elucidates the protective potential of bromelain against dichlorvos intoxication in mice brains. Dichlorvos induces the oxidative stress by disproportionating the balance between free radicals generation and their scavenging in neurons which leads to neuronal degeneration.

    METHODS: In this study, mice were divided into four groups- group I (control), group II (dichlorvos treated), group III (bromelain treated) and group IV (exposed to both bromelain and dichlorvos both).

    RESULTS: Dichlorvos treatment increased the levels of thiobarbituric acid reactive substances (TBARS) and protein carbonyl content (PCC) which indicate the increased oxidative stress. Meanwhile, brain endogenous antioxidants and cholinesterases level was decreased after dichlorvos exposure. Levels of TBARS and PCC decreased whereas cholinesterases level was recorded to be elevated after bromelain exposure.

    CONCLUSION: Bromelain offered neuroprotection by decreasing oxidative stress and augmenting cholinesterases in mice brains. This study highlights the invulnerability of bromelain against oxidative and cholinergic deficits in mice brains.

  • RESEARCH ARTICLE
    Kavitha S, Vimala Raghavan
    Frontiers in Biology, 2018, 13(3): 208-214. https://doi.org/10.1007/s11515-018-1496-0

    BACKGROUND: Diverse aquatic microorganisms are capable of colonizing living and non-living surfaces leading to the formation of biofilms. Commonly visualized as a slimy layer, these biofilms are filled with hundreds of other microorganisms compared to free living planktonic cells. Microbial surface colonization and surface-associated metabolic activities also exert several macroscale deleterious effects, including biofouling, biocorrosion and the persistence and transmission of harmful or pathogenic microorganisms and virulence determinants. The present study deals with the isolation and screening of marine bacteria for biofilm formation. The screened isolates were characterized and identified as Psychrobacter celer, Psychrobacter alimentarius and Kocuria rhizophila by 16S rRNA sequencing.

    METHODS: Biofilm forming bacteria were isolated by spread plate technique and subjected to screening by microtiter plate assay. The potent biofilm formers were identified by molecular characterization using 16S rRNA gene sequencing.

    RESULTS: Twelve bacterial isolates were obtained by pour plate technique and subjected to biofilm assay. Among the 12 isolates three isolates which showed maximum biofilm formation were subjected to molecular characterizationby 16S rRNA gene sequencing method. The isolates were identified as Psychrobacter celer, Psychrobacter alimentarius and Kocuria rhizophila. The EPS produced by the three biofilm forming bacteria was extracted and the protein and carbohydrate content determined.

    CONCLUSION: Among the isolates screened, isolate 8 (Kocuria rhizophila) produced maximum protein and carbohydrate which was also in accordance with the results of microtiter plate assay.

  • REVIEW
    Javad Mohammdai-asl,Abolfazl Ramezani,Fatemeh Norozi,Amal Saki Malehi,Ali Amin Asnafi,Mohammad Ali Jalali Far,Seyed Hadi Mousavi,Najmaldin Saki
    Frontiers in Biology, 2015, 10(4): 321-332. https://doi.org/10.1007/s11515-015-1365-z

    MicroRNAs (miRNAs) are 19-24 nucleotide non-coding ribonucleic acids binding DNA or RNA and controlling gene expression via mRNA degradation or its transcription inhibition. Erythropoies is a multi step differentiation process of erythroid progenitors to nucleate red blood cells. Maturation, proliferation and differentiation of red blood cells is affected by erythroid factors, signaling pathways in niche of hematopoietic cells, transcription factors as well as miRNAs. Expression of different types of miRNAs during erythroid development provides a background for the study of these molecules to control erythroid differentiation and maturation as well as their use as diagnostic and prognostic markers to treat erythroid disorders like thalassemia, sickle cell disease and erythrocyte enzyme deficiencies. In this paper, with reference to biosynthesis of miRNAs, their function in normal and anemic erythropoiesis has been investigated. The target molecule of each of these miRNAs has been cited in an attempt to elucidate their role in erythropoiesis.

  • REVIEW
    Xinwei LI, Jianqiang LI, Djaja D. SOEJARTO
    Frontiers in Biology, 2009, 4(1): 55-61. https://doi.org/10.1007/s11515-008-0110-2

    Actinidia (Actinidiaceae) is of economic importance for its edible fruits. Traditional taxonomy divided the genus into four sections, Leiocarpae Dunn, Maculatae Dunn, Strigosae Li, and Stellatae Li. However, phylogenetic studies based on morphology and molecular markers have posed challenges to the four-section scheme. It appears that the natural classification of the genus points to the existence of two groups, one comprising Leiocarpae, and the other Maculatae, Strigosae, and Stellatae. Single- or low-copy genes would probably be useful in untangling the perplexity and the reticulate evolution of the genus. However, any phylogenetic studies must be firmly based on sound taxonomy and identification. Population sampling throughout the distribution range of the taxa should be carried out in order to study the variation pattern of the morphology and, ultimately, to clarify the confusion existing in some taxa. A combination of morphometrics and molecular data is highly desirable for resolving the uncertainty in Actinidia taxonomy.

  • RESEARCH ARTICLE
    Zhaopei ZHANG, Liyuan NIU, Xiling CHEN, Xu XU, Zhengang RU
    Frontiers in Biology, 2012, 7(4): 374-377. https://doi.org/10.1007/s11515-012-2127-9

    Cryosection in plants is usually challenging because of the larger amounts of water contained in plant cell than animal cell. The formation of ice crystals within the plant cells easily destroys subcellular detail during freeze processing. And cell walls make freezing plant tissues hardly sliced and preserve the cell structure in subtle ways. In this study, the technique was improved on infusion, embedding and flatting sections with the winter wheat Variety Aikang58 as raw material.

  • REVIEW
    Felicia Tsang,Su-Ju Lin
    Frontiers in Biology, 2015, 10(4): 333-357. https://doi.org/10.1007/s11515-015-1367-x

    Nutrient sensing pathways and their regulation grant cells control over their metabolism and growth in response to changing nutrients. Factors that regulate nutrient sensing can also modulate longevity. Reduced activity of nutrient sensing pathways such as glucose-sensing PKA, nitrogen-sensing TOR and S6 kinase homolog Sch9 have been linked to increased life span in the yeast, Saccharomyces cerevisiae, and higher eukaryotes. Recently, reduced activity of amino acid sensing SPS pathway was also shown to increase yeast life span. Life span extension by reduced SPS activity requires enhanced NAD+ (nicotinamide adenine dinucleotide, oxidized form) and nicotinamide riboside (NR, a NAD+ precursor) homeostasis. Maintaining adequate NAD+ pools has been shown to play key roles in life span extension, but factors regulating NAD+ metabolism and homeostasis are not completely understood. Recently, NAD+ metabolism was also linked to the phosphate (Pi)-sensing PHO pathway in yeast. Canonical PHO activation requires Pi-starvation. Interestingly, NAD+ depletion without Pi-starvation was sufficient to induce PHO activation, increasing NR production and mobilization. Moreover, SPS signaling appears to function in parallel with PHO signaling components to regulate NR/NAD+ homeostasis. These studies suggest that NAD+ metabolism is likely controlled by and/or coordinated with multiple nutrient sensing pathways. Indeed, cross-regulation of PHO, PKA, TOR and Sch9 pathways was reported to potentially affect NAD+ metabolism; though detailed mechanisms remain unclear. This review discusses yeast longevity-related nutrient sensing pathways and possible mechanisms of life span extension, regulation of NAD+ homeostasis, and cross-talk among nutrient sensing pathways and NAD+ homeostasis.

  • REVIEW
    Fatih Semerci,Mirjana Maletic-Savatic
    Frontiers in Biology, 2016, 11(3): 151-167. https://doi.org/10.1007/s11515-016-1405-3

    The mammalian hippocampus shows a remarkable capacity for continued neurogenesis throughout life. Newborn neurons, generated by the radial neural stem cells (NSCs), are important for learning and memory as well as mood control. During aging, the number and responses of NSCs to neurogenic stimuli diminish, leading to decreased neurogenesis and age-associated cognitive decline and psychiatric disorders. Thus, adult hippocampal neurogenesis has garnered significant interest because targeting it could be a novel potential therapeutic strategy for these disorders. However, if we are to use neurogenesis to halt or reverse hippocampal-related pathology, we need to understand better the core molecular machinery that governs NSC and their progeny. In this review, we summarize a wide variety of mouse models used in adult neurogenesis field, present their advantages and disadvantages based on specificity and efficiency of labeling of different cell types, and review their contribution to our understanding of the biology and the heterogeneity of different cell types found in adult neurogenic niches.

  • REVIEW
    Huyin HUAI, Alan HAMILTON
    Frontiers in Biology, 2009, 4(2): 151-157. https://doi.org/10.1007/s11515-008-0103-1

    Traditional agroecosystems play an important role in the conservation of biodiversity and in sustainable development. As a typical type of traditional agroecosystem, traditional homegardens have been receiving increasing attention from scientists, especially ethnobotanists. They are considered as germplasm banks for many crops and other economic plants. They are also a key site for domestication of wild plants. Current ethnobotanical studies on homegardens focus on their structures, floristic composition, and contributions to their owners. Traditional homegardens often show complicated structures, diverse floristic compositions, multiple functions, low input (including labor and money), and ecological and socioeconomic sustainability. The characteristics and functions of traditional homegardens are closely related to many factors, such as their geographic location and the cultural backgrounds and socioeconomic conditions of their owners. Many researches on homegardens are conducted in the tropics. There are few studies on the dynamics of traditional homegardens, especially those located in temperate, arid and semi-arid zones. The dynamics of homegardens and the factors affecting these processes will be a fruitful field for future research.

  • RESEARCH ARTICLE
    Suki ROY,Ishita DAS,Minki MUNJAL,Loganathan KARTHIK,Gaurav KUMAR,Sathish KUMAR,Kokati Venkata Bhaskara RAO
    Frontiers in Biology, 2014, 9(4): 306-316. https://doi.org/10.1007/s11515-014-1324-0

    The present study was focused on screening and characterization of tyrosinase enzyme produced by marine actinobacteria and its application in phenolic compounds removal from aqueous solution. A total of 20 strains were isolated from marine sediment sample and screened for tyrosinase production by using skimmed milk agar medium. Among 20 isolates, two isolates LK-4 and LK-20 showed zone of hydrolysis and these were taken for secondary screening by using tyrosine agar medium. Based on the result of secondary screening LK-4 was selected for further analysis, such as tyrosinase assay, protein content and specific activity of the enzyme. The tyrosinase enzyme was produced in a SS medium and was partially purified by ammonium sulfate precipitation, dialysis and SDS PAGE. The isolate (LK-4) was identified as Streptomyces espinosus using 16S rRNA gene sequencing and named as “Streptomyces espinosus strain LK4 (KF806735)”. The tyrosinase enzyme was immobilized in sodium alginate which was applied to remove phenolic compounds from water. The enzyme efficiently removed the phenolic compounds from aqueous solution within few hours which indicated that tyrosinase enzyme produced by Streptomyces espinosus strain LK-4 can be potently used for the removal of phenol and phenolic compounds from wastewater in industries.

  • RESEARCH ARTICLE
    Peyman Hadi, Karimeh Haghani, Ali Noori-Zadeh, Salar Bakhtiyari
    Frontiers in Biology, 2018, 13(6): 464-468. https://doi.org/10.1007/s11515-018-1508-0

    BACKGROUND: Fragile X syndrome (FXS), an X-linked disorder, is the most common cause of inherited mental retardation. This is caused by a trinucleotide CGG repeat expansion (>200) on the fragile X mental retardation 1 gene (FMR1) becoming methylated leading to a deficiency or absence of the FMR1 protein. Determining FXS prevalence in the mentally retarded individuals in the west of Iran was the aim of this study.

    METHODS: 200 patients with moderate mental retardation who were clinically suspicious to FXS were screened using cytogenetic and molecular methods. Blood samples were collected and cultured in the specific culture media. The G-Banding method was used for karyotyping and DNA sequencing performed for verifying the results of the cytogenetic tests.

    RESULTS: 16 patients (8%) were found to have fragile X syndrome. The results showed that there is no significant association between the fragile X syndrome and economic status and place of residence, however, the relationship between fragile X syndrome and mental retardation in the family history is significant.

    CONCLUSION: The frequency of FXS was similar to other reports in the preselected patients. For diagnosis of FXS, chromosome analysis must be accompanied by molecular studies.

  • REVIEW
    Xiaonan TI, Qunchi ZHANG
    Frontiers in Biology, 2009, 4(3): 289-297. https://doi.org/10.1007/s11515-009-0017-6

    Any change in a plant that occurs following herbivory or environmental factors is an induced response. These changes include phytochemical induction, increases in physical defenses, emission of volatiles that attract predators and parasitoids of herbivores, and reduction in plant nutritional quality for herbivores, which is termed induced resistance. Induced resistance has been demonstrated ubiquitously in plants. It is one of our goals to review what is known about the induced resistance to herbivorous insects in cotton, including three resistance secondary metabolites (terpenoid, tannin, and flavonoids) that are contained at any significant levels of resistance to herbivorous insects in cotton cultivates. In many cases, the quantities or quality of secondary metabolites in plant are changed after attacked by insects. This review focuses on induced plant resistance as quantitative or qualitative enhancement of defense mechanism against insect pests, especially on the abiotic-elicitors-induced resistance in cotton plants. The abiotic-elicitor of cupric chloride, an exogenous inorganic compound, may induce the secondary metabolites accumulation and is referred to as a copper-inducible elicitor (CIE). Finally, we discuss how copper-inducible elicitor may be used in the Integrated Pest Management (IPM) system for cotton resistance control.

  • REVIEW
    Ying CAO, Ligeng MA
    Frontiers in Biology, 2011, 6(2): 109-117. https://doi.org/10.1007/s11515-011-1000-6

    Histone ubiquitination plays a critical role in the regulation of transcription, and histone H2B monoubiquitination (H2Bub1) is mainly associated with transcriptional activation. Recent studies in yeast, humans, and BoldItalic have revealed the conservation of chromatin modification via H2Bub1 during evolution. Rad6-Bre1 and their homologs are responsible for H2B monoubiquitination in diverse eukaryotic organisms, and the PAF complex is required for H2Bub1 to proceed. H2Bub1 is involved in many developmental processes in yeast, humans, and BoldItalic, and it activates gene transcription by regulating the H3K4 methylation state. Notably, the level of H3K4 methylation is entirely dependent on H2Bub1 in yeast and humans, whereas the H3K4 methylation level of only a small number of genes in BoldItalic is dependent on H2Bub1. In this review, we summarize the enzymes involved in H2B monoubiquitination and deubiquitination, and discuss the biologic functions of H2Bub1 in different organisms. In addition, we focus on recent advances in our understanding of the molecular mechanisms that enable H2Bub1 to perform its function.

  • Zhenming GE, ZHOU Xiao, SHI Wenyu, WANG Tianhou
    Frontiers in Biology, 2008, 3(4): 536-542. https://doi.org/10.1007/s11515-008-0068-0
    The carrying capacity of food resources for migrating shorebirds was estimated at a stopover site in the Yangtze River Estuary during the two migratory seasons (spring and autumn). From March to May and September to November 2005, the macrobenthos resources of the Jiuduansha Wetland were investigated, and most of the macrobenthos species in the newly-formed shoal were found to be appropriate food for shorebirds. Biomass measurements showed that the total food resource was about 4541.20 kg AFDW (Ash-Free Dry Weight) in spring and about 2279.64 kg AFDW in autumn. Calculations were also done in the available habitats (intertidal bare mudflat and Scirpus × mariqueter/Scirpus triqueter zones) for the shorebirds. The food resources in the available areas were about 3429.03 kg AFDW in spring and about 1700.92 kg AFDW in autumn. Based on the classification (by lean weight, basic metabolic rate and body length) of the shorebird community, and using the energy depletion model, it was theorized that all of the food resources in the Jiuduansha Wetland could support about 3.5 million shorebirds during spring season and 1.75 million shorebirds during autumn season. The shorebird carrying capacities in terms of the available food were about 2.6 million and 1.3 million birds during the two respective migration seasons. Considering the effect of intake rate, the potential carrying capacity was about 0.13–0.26 million shorebirds in the study area. The main factor restricting use of the area by shorebirds was the scarcity of available habitats for roosting at high tide rather than availability of food supply. We recommend restoring some wading pools in the dense Phragmites australis and Spartina alterniflora zones for shorebirds to roost in, to improve shorebirds’ utilization efficiency of the resources in the Jiuduansha Wetland.
  • Research articles
    Jinbiao MA, Ying HUANG,
    Frontiers in Biology, 2010, 5(1): 32-40. https://doi.org/10.1007/s11515-010-0004-y
    MicroRNAs (miRNAs) are a highly conserved class of small (18–24 nucleotides) non-coding RNAs that regulate a broad spectrum of biological processes. Aberrations or corruptions of miRNA functions may lead to deregulated cell proliferation, tumorigenesis, and ultimately, cancer. Increasing evidences suggested that a large fraction of miRNAs is regulated at the post-transcriptional stage, which impacts on the level and function of miRNAs during cell development and human diseases. Recently, several distinct mechanisms are emerging to regulate the biogenesis, stability and function of miRNAs at post-transcriptional level, such as specific binding to terminal loops of miRNA precursors (pri-miRNAs or pre-miRNAs) by RNA-binding proteins and 3’-terminal modifications by particular enzymes. Signaling cascades and post-translational modifications of the core components of RNA machinery also take part in the post-transcriptional regulation of miRNAs.
  • Research articles
    Richard D. Smrt, Xinyu Zhao,
    Frontiers in Biology, 2010, 5(4): 304-323. https://doi.org/10.1007/s11515-010-0650-0
    Dendrites and the dendritic spines of neurons play key roles in the connectivity of the brain and have been recognized as the locus of long-term synaptic plasticity, which is correlated with learning and memory. The development of dendrites and spines in the mammalian central nervous system is a complex process that requires specific molecular events over a period of time. It has been shown that specific molecules are needed not only at the spine’s point of contact, but also at a distance, providing signals that initiate a cascade of events leading to synapse formation. The specific molecules that act to signal neuronal differentiation, dendritic morphology, and synaptogenesis are tightly regulated by genetic and epigenetic programs. It has been shown that the dendritic spine structure and distribution are altered in many diseases, including many forms of mental retardation (MR), and can also be potentiated by neuronal activities and an enriched environment. Because dendritic spine pathologies are found in many types of MR, it has been proposed that an inability to form normal spines leads to the cognitive and motor deficits that are characteristic of MR. Epigenetic mechanisms, including DNA methylation, chromatin remodeling, and the noncoding RNA-mediated process, have profound regulatory roles in mammalian gene expression. The study of epigenetics focuses on cellular effects that result in a heritable pattern of gene expression without changes to genomic encoding. Despite extensive efforts to understand the molecular regulation of dendrite and spine development, epigenetic mechanisms have only recently been considered. In this review, we will focus on epigenetic mechanisms that regulate the development and maturation of dendrites and spines. We will discuss how epigenetic alterations could result in spine abnormalities that lead to MR, such as is seen in fragile X and Rett syndromes. We will also discuss both general methodology and recent technological advances in the study of neuronal dendrites and spines.
  • Research articles
    John J. CHEN,
    Frontiers in Biology, 2010, 5(4): 348-353. https://doi.org/10.1007/s11515-010-0580-x
    The discovery of the Hardy-Weinberg principle marked the beginning of the field of population genetics. Over the past hundred years, it has provided a starting point for many population genetic investigations. In this review, the Hardy-Weinberg principle, its statistical testing, and several of its applications in various modern population genetic research areas, including allelic variability and selection in the human leukocyte antigen region, microsatellite genotyping error detection, and accuracy of haplotype estimation, are discussed.
  • RESEARCH ARTICLE
    Sampriya SHARMA,Jitender SHARMA,Rishi Pal MANDHAN
    Frontiers in Biology, 2014, 9(4): 317-323. https://doi.org/10.1007/s11515-014-1316-0

    Production of high titers of an alkaline, extracellular and thermo-tolerant pectinase by a newly isolated yeast Pseudozyma sp. SPJ was carried out under solid state fermentation. Citrus peel, the inexpensive agro-industrial residue used as substrate, was experienced to be unsurpassed. Response surface methodology was conducted to optimize the culture conditions for Pseudozyma sp. SPJ for hyper production of pectinase. Plackett Burman design was applied to identify the most effective culture variables. Out of nine variables studied, incubation time, moisture content and ammonium sulfate were detected as most important. A full factorial Central Composite Design was used to optimize the levels of these variables, which resulted in 17-fold increase (71.19 IU/g to 1215.66 IU/g dry substrate) in the enzyme yield. The results of analysis of variance and multiple regression analysis implies that the effect of incubation time (p<0.000) and moisture content (p<0.018) is more than ammonium sulfate. And also the interaction of moisture content with ammonium sulfate (p<0.002) is more significant.

  • REVIEW
    Annalisa Zecchin,Aleksandra Brajic,Peter Carmeliet
    Frontiers in Biology, 2015, 10(2): 125-140. https://doi.org/10.1007/s11515-015-1350-6

    Endothelial cells (ECs) line blood vessels and function as a vital conduit for oxygen and nutrients, but can also form vascular niches for various types of stem cells. While mostly quiescent throughout adult life, ECs can rapidly switch to a highly active state, and start to sprout in order to form new blood vessels. ECs can also become dysfunctional, as occurs in diabetes and atherosclerosis. Recent studies have demonstrated a key role for EC metabolism in the regulation of angiogenesis, and showed that EC metabolism is even capable of overriding genetic signals. In this review, we will review the basic principles of EC metabolism and focus on the metabolic alterations that accompany EC dysfunction in diabetes and vessel overgrowth in cancer. We will also highlight how EC metabolism influences EC behavior by modulating post-translational modification and epigenetic changes, and illustrate how dietary supplementation of metabolites can change EC responses. Finally, we will discuss the potential of targeting EC metabolism as a novel therapeutic strategy.

  • REVIEW
    Andrew Brandmaier, Sheng-Qi Hou, Sandra Demaria, Silvia C. Formenti, Wen H. Shen
    Frontiers in Biology, 2017, 12(3): 163-174. https://doi.org/10.1007/s11515-017-1443-5

    BACKGROUND: PTEN is well known to function as a tumor suppressor that antagonizes oncogenic signaling and maintains genomic stability. ThePTEN gene is frequently deleted or mutated in human cancers and the wide cancer spectrum associated with PTEN deficiency has been recapitulated in a variety of mouse models ofPten deletion or mutation. Pten mutations are highly penetrant in causing various types of spontaneous tumors that often exhibit resistance to anticancer therapies including immunotherapy. Recent studies demonstrate that PTEN also regulates immune functionality.

    OBJECTIVE: To understand the multifaceted functions of PTEN as both a tumor suppressor and an immune regulator.

    METHODS: This review will summarize the emerging knowledge of PTEN function in cancer immunoediting. In addition, the mechanisms underlying functional integration of various PTEN pathways in regulating cancer evolution and tumor immunity will be highlighted.

    RESULTS: Recent preclinical and clinical studies revealed the essential role of PTEN in maintaining immune homeostasis, which significantly expands the repertoire of PTEN functions. Mechanistically, aberrant PTEN signaling alters the interplay between the immune system and tumors, leading to immunosuppression and tumor escape.

    CONCLUSION: Rational design of personalized anti-cancer treatment requires mechanistic understanding of diverse PTEN signaling pathways in modulation of the crosstalk between tumor and immune cells.

  • RESEARCH ARTICLE
    Vadakkemuriyil DIVYA NAIR, Cheruth Abdul JALEEL, Ragupathi GOPI, Rajaram PANNEERSELVAM
    Frontiers in Biology, 2009, 4(2): 192-199. https://doi.org/10.1007/s11515-009-0001-1

    A field experiment was conducted to investigate the effect of growth regulators on growth characteristics such as root length, shoot length, total leaf area, number of inflorescence per plant, number of flower per inflorescence, whole plant fresh weight and whole plant dry weight. Photosynthetic characteristics were also analyzed based on the same experiment. For this, various photosynthetic pigment contents such as chlorophyll, carotenoid, anthocyanin and xanthophyll content were calculated. The conventional growth regulator abscisic acid (ABA) and non-conventional growth regulator triazole compound paclobutrazol (PBZ) were used. Root length increased due to growth regulator treatment, but shoot length decreased. Leaf area was decreased due to growth regulator treatment. The number of inflorescence increased in ABA treated plants, but it was decreased in PBZ treated plants. In ABA treated plants, the number of flowers per inflorescence was increased. In PBZ treated plants the number of inflorescence was reduced. The whole plant fresh weight (FW) and dry weight (DW) were increased in ABA and PBZ treated plants. There was an increase in chlorophyll content in growth regulator treated plants compared to control, and it was more in PBZ treated plants. The carotenoid content was also increased in ABA and PBZ treated plants.

  • REVIEW
    Xiaoyun JIA, Jun YAN, Guiliang TANG
    Frontiers in Biology, 2011, 6(2): 133-139. https://doi.org/10.1007/s11515-011-1136-4

    DNA methylation, a major event in epigenetics, plays an essential role in the control of gene expression. Increasing evidence suggests that long and short non-coding RNAs are involved extensively in plants to direct the establishment, spread, and removal of DNA cytosine methylation throughout their genomes. Yet, little has been known about the role of microRNAs (miRNAs) in DNA methylation although the role of small interfering RNAs (siRNAs) in DNA methylation has been well established. Several recent studies, however, provided the evidence for miRNA-directed DNA methylation in plants, and the working mechanisms still need to be fully explored. In this review, we highlight the key features of miRNA-directed DNA methylation in plants and provide insight into the complexities of such an event in plants. The interaction between miRNAs and the epigenetic machinery and the future potential research questions are briefly discussed.

  • ZHOU Shurong, ZHANG Dayong
    Frontiers in Biology, 2008, 3(1): 1-8. https://doi.org/10.1007/s11515-008-0008-z
    One of the central goals of community ecology is to understand the forces that maintain species diversity within communities. The traditional niche-assembly theory asserts that species live together in a community only when they differ from one another in resource uses. But this theory has some difficulties in explaining the diversity often observed in specie-rich communities such as tropical forests. As an alternative to the niche theory, Hubbell and other ecologists introduced a neutral model. Hubbell argues that the number of species in a community is controlled by species extinction and immigration or speciation of new species. Assuming that all individuals of all species in a trophically similar community are ecologically equivalent, Hubbell’s neutral theory predicts two important statistical distributions. One is the asymptotic log-series distribution for the metacommunities under point mutation speciation, and the other is the zero-sum multinomial distribution for both local communities under dispersal limitation and metacommunities under random fission speciation. Unlike the niche-assembly theory, the neutral theory takes similarity in species and individuals as a starting point for investigating species diversity. Based on the fundamental processes of birth, death, dispersal and speciation, the neutral theory provided the first mechanistic explanation of species abundance distribution commonly observed in natural communities. Since the publication of the neutral theory, there has been much discussion about it, pro and con. In this paper, we summarize recent progress in the assumption, prediction and speciation mode of the neutral theory, including progress in the theory itself, tests about the assumption of the theory, prediction and speciation mode at the metacommunity level. We also suggest that the most important task in the future is to bridge the niche-assembly theory and the neutral theory, and to add species differences to the neutral theory and more stochasticity to the niche theory.