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Fulltext Effect of extraction temperature on polyphenolic content and antioxidant potential of Gynura crepioides leaves

Malarvili, M. W, Bibu Prasad P., Bin Seng L., Naveen Kumar, H. S.

Malaysian Journal of Medicine and Health Sciences, 2019;15(102):10-10.
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Introduction: Gynura crepioides (G. crepioides) belongs to the Asteraceae family and native to Southeast Asia, especially Indonesia. Gynura genuses are well known for their antioxidant properties. Hence, the current study aimed to study the effect of temperature on polyphenololic content and antioxidant properties on G. crepioides leaves extract. Methods: The extraction of G. crepioides leaves was carried out by Ultrasound-assisted extraction (UAE) method for 60 minutes by using ethanol (70 %) at three different temperatures 25°C and 50°C and 75°C. The total polyphenolic content (TPC) was investigated by using Folin-Ciocalteu assay, whereas the antioxidant potential (AOP) was determined by using phosphomolybdenum assay, and 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. Results: The results from the study showed that TPC of G. crepioides extracted at 25°C was significantly (p < 0.05) lower than 50°C and 75°C with 8.45 ± 0.31 mg GAE/g, 35.83 ± 1.22 mg GAE/g, 35.90 ± 0.78 mg GAE/g respectively. However, the results from AOP has demonstrated lower value of 70.62 ± 0.74 mg AAE/g at 75°C compare to 77.67 ± 0.26 mg AAE/g at 25°C and 81.53 ± 0.68 mg AAE/g at 50°C. From DPPH assay results revealed that extraction temperature at 50°C has EC50 (p < 0.05) lowest value of 92.64 ± 0.56 µg/mL compared to G. crepioides extracted at 25°C (98.50 ± 1.18 µg/mL) and 75°C (101.72 ± 9.09 µg/mL). An excellent correlation exhibited between TAC and DPPH radical scavenging assays with r = 0.95 and r2 = 0.89. Present study reveals that UAE method with 70% ethanol, 60 minutes extraction time at 50°C temperature is an optimum to extract highest phenolic content and antioxidants from G. crepioides leaves. Conclusion: It was concluded from the study that extraction temperature would affect the extraction of phytochemicals from plants in turn it affects the biological activities.
Fulltext Role of serotonin in fish reproduction

Prasad P, Ogawa S, Parhar IS

Front Neurosci, 2015;9:195.
PMID: 26097446 DOI: 10.3389/fnins.2015.00195

The neuroendocrine mechanism regulates reproduction through the hypothalamo-pituitary-gonadal (HPG) axis which is evolutionarily conserved in vertebrates. The HPG axis is regulated by a variety of internal as well as external factors. Serotonin, a monoamine neurotransmitter, is involved in a wide range of reproductive functions. In mammals, serotonin regulates sexual behaviors, gonadotropin release and gonadotropin-release hormone (GnRH) secretion. However, the serotonin system in teleost may also play unique role in the control of reproduction as the mechanism of reproductive control in teleosts is not always the same as in the mammalian models. In fish, the serotonin system is also regulated by natural environmental factors as well as chemical substances. In particular, selective serotonin reuptake inhibitors (SSRIs) are commonly detected as pharmaceutical contaminants in the natural environment. Those factors may influence fish reproductive functions via the serotonin system. This review summarizes the functional significance of serotonin in the teleosts reproduction.
Fulltext Serotonin reuptake inhibitor citalopram inhibits GnRH synthesis and spermatogenesis in the male zebrafish

Prasad P, Ogawa S, Parhar IS

Biol Reprod, 2015 Oct;93(4):102.
PMID: 26157069 DOI: 10.1095/biolreprod.115.129965

Selective serotonin reuptake inhibitors (SSRIs) are widely used antidepressants for the treatment of depression. However, SSRIs cause sexual side effects such as anorgasmia, erectile dysfunction, and diminished libido that are thought to be mediated through the serotonin (5-hydroxytryptamine, 5-HT) system. In vertebrates, gonadotropin-releasing hormone (GnRH) neurons play an important role in the control of reproduction. To elucidate the neuroendocrine mechanisms of SSRI-induced reproductive failure, we examined the neuronal association between 5-HT and GnRH (GnRH2 and GnRH3) systems in the male zebrafish. Double-label immunofluorescence and confocal laser microscopy followed by three-dimensional construction analysis showed close associations between 5-HT fibers with GnRH3 fibers and preoptic-GnRH3 cell bodies, but there was no association with GnRH2 cell bodies and fibers. Quantitative real-time PCR showed that short-term treatment (2 wk) with low to medium doses (4 and 40 μg/L, respectively) of citalopram significantly decreased mRNA levels of gnrh3, gonadotropins (lhb and fshb) and 5-HT-related genes (tph2 and sert) in the male zebrafish. In addition, short-term citalopram treatment significantly decreased the fluorescence density of 5-HT and GnRH3 fibers compared with controls. Short-term treatment with low, medium, and high (100 μg/L) citalopram doses had no effects on the profiles of different stages of spermatogenesis, while long-term (1 mo) citalopram treatment with medium and high doses significantly inhibited the different stages of spermatogenesis. These results show morphological and functional associations between the 5-HT and the hypophysiotropic GnHR3 system, which involve SSRI-induced reproductive failures.
Fulltext Activating RAC1 variants in the switch II region cause a developmental syndrome and alter neuronal morphology

Banka S, Bennington A, Baker MJ, Rijckmans E, Clemente GD, Ansor NM, et al.

Brain, 2022 Dec 19;145(12):4232-4245.
PMID: 35139179 DOI: 10.1093/brain/awac049

RAC1 is a highly conserved Rho GTPase critical for many cellular and developmental processes. De novo missense RAC1 variants cause a highly variable neurodevelopmental disorder. Some of these variants have previously been shown to have a dominant negative effect. Most previously reported patients with this disorder have either severe microcephaly or severe macrocephaly. Here, we describe eight patients with pathogenic missense RAC1 variants affecting residues between Q61 and R68 within the switch II region of RAC1. These patients display variable combinations of developmental delay, intellectual disability, brain anomalies such as polymicrogyria and cardiovascular defects with normocephaly or relatively milder micro- or macrocephaly. Pulldown assays, NIH3T3 fibroblast spreading assays and staining for activated PAK1/2/3 and WAVE2 suggest that these variants increase RAC1 activity and over-activate downstream signalling targets. Axons of neurons isolated from Drosophila embryos expressing the most common of the activating variants are significantly shorter, with an increased density of filopodial protrusions. In vivo, these embryos exhibit frequent defects in axonal organization. Class IV dendritic arborization neurons expressing this variant exhibit a significant reduction in the total area of the dendritic arbour, increased branching and failure of self-avoidance. RNAi knock down of the WAVE regulatory complex component Cyfip significantly rescues these morphological defects. These results establish that activating substitutions affecting residues Q61-R68 within the switch II region of RAC1 cause a developmental syndrome. Our findings reveal that these variants cause altered downstream signalling, resulting in abnormal neuronal morphology and reveal the WAVE regulatory complex/Arp2/3 pathway as a possible therapeutic target for activating RAC1 variants. These insights also have the potential to inform the mechanism and therapy for other disorders caused by variants in genes encoding other Rho GTPases, their regulators and downstream effectors.
Fulltext Response and resilience of Asian agrifood systems to COVID-19: An assessment across twenty-five countries and four regional farming and food systems

Dixon JM, Weerahewa J, Hellin J, Rola-Rubzen MF, Huang J, Kumar S, et al.

Agric Syst, 2021 Oct;193:103168.
PMID: 36284566 DOI: 10.1016/j.agsy.2021.103168

CONTEXT: The COVID-19 pandemic has been affecting health and economies across the world, although the nature of direct and indirect effects on Asian agrifood systems and food security has not yet been well understood.
OBJECTIVES: This paper assesses the initial responses of major farming and food systems to COVID-19 in 25 Asian countries, and considers the implications for resilience, food and nutrition security and recovery policies by the governments.
METHODS: A conceptual systems model was specified including key pathways linking the direct and indirect effects of COVID-19 to the resilience and performance of the four principal Asian farming and food systems, viz, lowland rice based; irrigated wheat based; hill mixed; and dryland mixed systems. Based on this framework, a systematic survey of 2504 key informants (4% policy makers, 6% researchers or University staff, 6% extension workers, 65% farmers, and 19% others) in 20 Asian countries was conducted and the results assessed and analysed.
RESULTS AND CONCLUSION: The principal Asian farming and food systems were moderately resilient to COVID-19, reinforced by government policies in many countries that prioritized food availability and affordability. Rural livelihoods and food security were affected primarily because of disruptions to local labour markets (especially for off-farm work), farm produce markets (notably for perishable foods) and input supply chains (i.e., seeds and fertilisers). The overall effects on system performance were most severe in the irrigated wheat based system and least severe in the hill mixed system, associated in the latter case with greater resilience and diversification and less dependence on external inputs and long market chains. Farming and food systems' resilience and sustainability are critical considerations for recovery policies and programmes, especially in relation to economic performance that initially recovered more slowly than productivity, natural resources status and social capital. Overall, the resilience of Asian farming and food systems was strong because of inherent systems characteristics reinforced by public policies that prioritized staple food production and distribution as well as complementary welfare programmes. With the substantial risks to plant- and animal-sourced food supplies from future zoonoses and the institutional vulnerabilities revealed by COVID-19, efforts to improve resilience should be central to recovery programmes.
SIGNIFICANCE: This study was the first Asia-wide systems assessment of the effects of COVID-19 on agriculture and food systems, differentiating the effects of the pandemic across the four principal regional farming and food systems in the region.