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Frontiers in Biology

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, Volume 13 Issue 2 Previous Issue   
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An overview of pyrethroid insecticides
Anudurga Gajendiran, Jayanthi Abraham
Front. Biol.. 2018, 13 (2): 79-90.
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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.

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Drosophila, destroying angels, and deathcaps! Oh my! A review of mycotoxin tolerance in the genus Drosophila
Clare H. Scott Chialvo, Thomas Werner
Front. Biol.. 2018, 13 (2): 91-102.
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BACKGROUND: Evolutionary novelties, be they morphological or biochemical, fascinate both scientists and non-scientists alike. These types of adaptations can significantly impact the biodiversity of the organisms in which they occur. While much work has been invested in the evolution of novel morphological traits, substantially less is known about the evolution of biochemical adaptations.

METHODS: In this review, we present the results of literature searches relating to one such biochemical adaptation: α-amanitin tolerance/resistance in the genus Drosophila.

RESULTS: Amatoxins, including α-amanitin, are one of several toxin classes found in Amanita mushrooms. They act by binding to RNA polymerase II and inhibiting RNA transcription. Although these toxins are lethal to most eukaryotic organisms, 17 mushroom-feeding Drosophila species are tolerant of natural concentrations of amatoxins and can develop in toxic mushrooms. The use of toxic mushrooms allows these species to avoid infection by parasitic nematodes and lowers competition. Their amatoxin tolerance is not due to mutations that would inhibit α-amanitin from binding to RNA polymerase II. Furthermore, the mushroom-feeding flies are able to detoxify the other toxin classes that occur in their mushroom hosts. In addition, resistance has evolved independently in several D. melanogaster strains. Only one of the strains exhibits resistance due to mutations in the target of the toxin.

CONCLUSIONS: Given our current understanding of the evolutionary relationships among the mushroom-feeding flies, it appears that amatoxin tolerance evolved multiple times. Furthermore, independent lines of evidence suggest that multiple mechanisms confer α-amanitin tolerance/resistance in Drosophila.

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Clastogenic ROS and biophotonics in precancerous diagnosis
Muhammad Naveed, Mohammad Raees, Irfan Liaqat, Mohammad Kashif
Front. Biol.. 2018, 13 (2): 103-122.
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BACKGROUND: Cancer is the leading cause of death worldwide. The application of biophotonics for diagnosing precancerous lesions is a major breakthrough in oncology and is associated with the expression of clastogenic bio-markers, such as reactive oxygen species (ROS), namely, superoxide anion radicals, hydrogen peroxide, hydroxyl radicals, and lipid peroxidation products. These ROS are the major sources of ultra-weak biophotons emission; in addition, biophotons are emitted from other biomolecules, which are not associated with ROS. The precancerous phase is diagnosed on the basis of biophoton emission from biomarkers. The type of biophotons emitted depends on the structure of the clastogenic ROS.

METHODS: ROS-based emission of ultra-weak photons can be detected using charge coupled device (CCD) cameras and photomultiplier tubes. Furthermore, spectroscopic and microscopic analysis can yield more advanced and definite results.

RESULTS: The frequency and intensity of biophoton emission associated with each ROS provides information regarding the precancerous phase. Previous have attempted to show an association between precancerous growth and biophoton emission; however, their results were not conclusive. In this review, we have addressed multiple aspects of the molecular environment, especially light- matter interactions, to derive a successful theoretical relationship which may have the ability to diaganose the tumor at precancerous stage and to give the solutions of previous failures. This can be a major quantum leap toward precancerous diagnosis therapy.

CONCLUSION: Biophotonics provides an advanced framework, for easily diagnosing cancer at its preliminary stage. The relationship between biophotons, clastogenic factors, and biochemical reactions in the cellular microenvironment can be understood successfully. The advancement in precancerous diagnosis will improve human health worldwide. The versatility of biophotonics can be used further for novel applications in biology, biochemistry, chemistry and social fields.

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Media optimization for extracellular amylase production by Pseudomonas balearica vitps19 using response surface methodology
Moni Philip Jacob Kizhakedathil, Subathra Devi Chandrasekaran
Front. Biol.. 2018, 13 (2): 123-129.
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BACKGROUND: In this study, we optimized the process for enhancing amylase production from Pseudomonas balearica VITPS19 isolated from agricultural lands in Kolathur, India.

METHODS: Process optimization for enhancing amylase production from the isolate was carried out by Response Surface Methodology (RSM) with optimized chemical and physical sources using Design expert v.7.0. A central composite design was used to evaluate the interaction between parameters. Interaction between four factors – maltose (C-source), malt extract (N-source), pH, and CaCl2 was studied.

RESULTS: The factors pH and CaCl2 concentration were found to affect amylase production. Validation of the experiment showed a nearly twofold increase in alpha amylase production.

CONCLUSION: Amylase production was thus optimized and increased yield was achieved.

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Zingiber officinale extends Drosophila melanogaster life span in xenobiotic-induced oxidative stress conditions
Volodymyr Padalko, Viktoriya Dzyuba, Olena Kozlova, Hanna Sheremet, Olena Protsenko
Front. Biol.. 2018, 13 (2): 130-136.
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BACKGROUND: The possibility of dietary ginger to enhance oxidative stress resistance and to extend life span was studied on Drosophila melanogaster.

METHODS: Oxidative stress was induced by a reducing agent dithiothreitol. Experimental groups of male D. melanogaster were cultured on media containing: 1) no additive; 2) dithiothreitol, added into the nutritional mixture to the final concentration of 10 mM; 3) 25 mg of ginger powder g–1 of the nutritional mixture; and 4) 10 mM of dithiothreitol and 25 mg of ginger powder g–1 of the nutritional mixture. The number of alive fruit flies was inspected daily, and mean life span was determined for each experimental group.

RESULTS: The addition of dithiothreitol to D. melanogaster nutritional mixture was established to result in an increase in concentration of two markers of oxidative stress conditions (thiobarbituric acid reactive substances as products of lipid peroxidation and carbonylated proteins as products of protein oxidation) in fly tissues. It was followed by significant reduction of mean life span and maximum life span of the last 10% of flies. Plant preparation, being added simultaneously with dithiothreitol, significantly diminished the negative effects of this xenobiotic. In conditions of additional stress load induced by hydrogen peroxide or high temperature, survival of insects treated with dithiothreitol on the background of ginger powder was the highest.

CONCLUSIONS: Thus, the presented data give the evidence that ginger preparations can reduce oxidative stress outcomes and significantly increase the life expectancy of fruit flies in stress conditions.

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Insulin inhibits the JNK mediated cell death via upregulation of AKT expression in Schwann cells grown in hyperglycemia
Mallahalli S. Manu, Kuruvanthe S. Rachana, Gopal M. Advirao
Front. Biol.. 2018, 13 (2): 137-144.
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BACKGROUND: Schwann cells (SCs) are the glial cells of the peripheral nervous system, which forms a thick insulating structure around the axons. Hyperglycemia is known physiologic conditions in both type I and type II diabetes which causes diabetic neuropathy. But the SC possesses insulin receptors even though glucose uptake is independent of insulin. Since the insulin level is highly altered in diabetes, it is of greater importance to evaluate their role in the Schwann cell survival and death.

METHODS: Schwann cells were isolated from neonatal pups and grown with and without insulin in hyperglycemic medium to mimic diabetic condition for 24 and 48 h. We studied the cell viability using 3 (4,5-dimethylthiazol-2-yl) 2,5-diphenyltetrazolium bromide (MTT) and mitochondrial membrane potential (MMP) assay at different time interval on SCs. We also studied the protein and gene expression of Protein Kinase B (AKT) and Jun N-terminal kinase (JNK), which are greatly involved in cell survival and cell death respectively.

RESULTS: The result shows that, high glucose levels for 48 h decrease the SC viability. Hyperglycemic condition induces the SC death by increasing the JNK expression which in turn reduces the MMP of glial cells. However, insulin administration for SCs grown in high glucose condition can reduce the JNK expression by activating AKT signaling pathway.

CONCLUSION: These observations demonstrate that the proper insulin balance is required for Schwann cells survival in hyperglycemic condition. Therefore, altered insulin signaling can be one of the reasons for demyelination of peripheral neurons in diabetic neuropathy.

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Effectiveness of fractional CO2 laser in women with stress urinary incontinence
Mahin Najafian, Yalda Jafrideh, Behnaz Ghazisaeidi
Front. Biol.. 2018, 13 (2): 145-148.
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BACKGROUND: Stress urinary incontinence (SUI) is a relatively common disorder that significantly affects the quality of life. Many conservative and surgical treatment methods have been recommended for SUI, but they have major limitations.

AIMS: To assess the use of the CO2 fractional laser in the treatment of SUI.

METHODS: This clinical trial included 55 patients with confirmed SUI. Patients underwent fractional CO2 laser treatment 3 times at 30-day intervals. Data on age, smoking history, sexual activity, menopause, and history of hormone replacement therapy (HRT) were collected. Response to treatment was assessed by SUI severity and the level of sexual satisfaction was assessed using the visual analog scale (VAS). Patients were evaluated at 3 different time points: before treatment, and 45 days and 6 months after the last laser treatment.

RESULTS: The mean patient age was 44.4±11.4 years (range: 28 to 68 years). Smoking history was positive in 6 patients (9.1%); 19 (54.3%) were menopausal on HRT. The SUI severity score at baseline (before treatment) was 8.56±0.62 and decreased to 2.28 6 months after treatment (p<0.0001). The sexual satisfaction score was 3±0.94 at baseline and increased to 7.87±0.93 6 months after treatment (day 180) (p<0.0001, slope= + 2.2)

CONCLUSION: Our findings are in line with a previous study that showed the value of transvaginal CO2 fractional laser treatment for alleviation of SUI symptoms and its potential as an alternative treatment. We also observed improved sexual satisfaction in SUI patients.

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Investigating the inhibition of NMDA glutamate receptors in the basolateral nucleus of the amygdala on the pain and inflammation induced by formalin in male Wistar rats
Nima Heidary, Hedayat Sahraei, Mohammad Reza Afarinesh, Zahra Bahari, Gholam Hossein Meftahi
Front. Biol.. 2018, 13 (2): 149-155.
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BACKGROUND: The role of the amygdala in controlling emotional pain has been emphasized in several studies. In this study, the role of the NMDA glutamate receptors in the basolateral nucleus of the amygdala (BLA) in regulating inflammation and emotional pain, induced by formalin, was studied in male rats.

METHODS: Male Wistar rats, weighing 250±20 g, were injected with 20 µL of 2% formalin into the paw of the right hind limb. Memantine, at doses of 1 and 5 mg/rat, was injected bilaterally into the BLA five minutes prior to injecting formalin. Following the injection, the pain and inflammation of the paws were measured using Dubbison-Dennis and mercury immersion methods, respectively. The behavior of the animals, including licking time and foot volume, was assessed.

RESULTS: The results showed that the inactivation of the NMDA receptors in the BLA in the acute phase of pain reduced the licking time (the emotional aspect of pain). However, at a high dose (5 µg/rat), memantine exacerbates the pain induced by formalin in the chronic phase. Additionally, the inhibition of the NMDA receptors in the BLA by memantine enhanced the formalin-induced increase in foot volume (inflammation) in a dose-dependent manner.

CONCLUSION: The study showed that the NMDA glutamate receptors in the BLA are crucial for the emotional pain and inflammation in both chronic and acute phases of formalin-induced pain. However, their roles are more pronounced in the chronic phase than in the acute phase of pain.

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8 articles