Triiodothyronine and melatonin influence antioxidant defense mechanism in a teleost Anabas testudineus (Bloch): in vitro study

The effect of the hormones triiodothyronine (T3) and melatonin on antioxidant defense system was studied in 6-propyl thiouracil (6-PTU)-treated or photoperiod-exposed teleost Anabas testudineus. 6-PTU (2 microg/g) treatment or photoperiod exposure (24 h) increased malondialdehyde (MDA) and conjugated dienes (CD) concentrations, indicating increased lipid peroxidation (LPO) in the experimental conditions. T3 or melatonin (10(-6) M) treatment for 15 min in vitro in PTU-treated fish reversed the activity of superoxide dismutase (SOD), catalase and glutathione content. T3-treated group showed no change in glutathione peroxidase (GPx) activity, whereas melatonin treatment decreased its activity. T3 inhibited glutathione reductase (GR) activity. Photoperiod exposure (physiological pinealotomy) induced a stressful situation in this teleost, as evidenced by LPO products and antioxidant enzyme activities. Melatonin and T3 treatment for 15 min in vitro also reversed the effect of photoperiod on peroxidation products and the SOD and catalase activities. GR activity decreased in photoperiod-exposed group and melatonin and T3 treatment reversed the activities. The antioxidant enzymes responded to the stress situation after 6-PTU treatment and photoperiod exposure by altering their activities. The study suggested an independent effect of T3 and melatonin on antioxidant defence mechanism in different physiological situations in fish.     

Organization of the aerotaxis receptor aer in the membrane of Escherichia coli

The Aer receptor guides Escherichia coli to specific oxygen and energy-generating niches. The input sensor in Aer is a flavin adenine dinucleotide-binding PAS domain, which is separated from a HAMP/signaling output domain by two membrane-spanning segments that flank a short (four-amino-acid) periplasmic loop. In this study, we determined the overall membrane organization of Aer by introducing combinations of residues that allowed us to differentiate intradimeric collisions from interdimeric collisions. Collisions between proximal residues in the membrane anchor were exclusively intra- or interdimeric but, with one exception, not both. Cross-linking profiles were consistent, with a rigid rather than flexible periplasmic loop and a tilted TM2 helix that crossed TM2' at residue V197C, near the center of the lipid bilayer. The periplasmic loop formed a stable neighborhood that (i) included a maximum of three Aer dimers, (ii) did not swap neighbors over time, and (iii) appeared to be constrained by interactions in the cytosolic signaling domain.     

Discovery of orally bioavailable and novel urea agonists of the high affinity niacin receptor GPR109A

A urea class of high affinity niacin receptor agonists was discovered. Compound 1a displayed good PK, better in vivo efficacy in reducing FFA in mouse than niacin, and no vasodilation in a mouse model. Compound 1q demonstrated equal affinity to GPR109A as niacin.     

Selective cytotoxicity of Pancratistatin-related natural <Emphasis Type="Italic">Amaryllidaceae</Emphasis> alkaloids: evaluation of the activity of two new compounds

Background  

Pancratistatin (PST), a compound extracted from an Amaryllidaceae (AMD) family plant, has been shown to specifically induce apoptosis in cancer cells with no/minimal toxic effect on normal cells. A systematic synthetic approach has indicated that the minimum cytotoxic pharmacophore comprises the trans-fused b/c-ring system containing the 2, 3, 4-triol unit in the C-ring. To further explore the structure-activity relationship of this group of compounds we have investigated the anti-cancer efficacy and specificity of two PST-related natural compounds, AMD4 and AMD5. Both of these compounds lack the polyhydroxylated lycorane element of PST instead having a methoxy-substuituted crinane skeleton.     

Growth factors upregulate deposition and remodeling of ECM by endothelial cells cultured for tissue-engineering applications

Appropriate matrix formation, turnover and remodeling in tissue-engineered small diameter vascular conduits are crucial for their long-term function. The interaction between cells and extra-cellular components is indispensable in determining cellular behavior in tissues and on biomaterials. The fibrin that contains fibronectin shows promise in most aspects as a tissue engineering scaffold, whereas, deposition of elastin and collagen by endothelial cells grown in the lumen of the construct is desirable to improve post implant retention, mechanical stability and vaso-responsiveness. So far there is no report on production of extra-cellular matrix (ECM) proteins, elastin and collagen by endothelial cells (EC) in in vitro culture conditions. In this study, we have used a biomimetic approach of providing multiple growth factors (GF) in the fibronectin (FN)-containing fibrin matrix to induce production of elastin and collagen by the endothelial cells for application in vascular tissue engineering. Deposition of elastin and collagens with matrix remodeling is demonstrated through qualitative analysis of the matrices that were recovered after growing cells on the initial fibrin-FN-GF matrix. Expressions of mRNA for both proteins were assessed by real time polymerase chain reaction (RT-PCR) to estimate the effects of multiple growth factor compositions. Marked deposition of elastin and collagen was evidenced by staining the recovered matrix after different culture intervals. Obviously, the biomimetic environment created by adding angiogenic and platelet growth factors in the fibrin-fibronectin-gelatin matrix can induce deposition of collagens and elastin by EC.     

Computational insights into diverse aspects of glutathione S-transferase gene family in Papaver somniferum

Journal of Plant Research - Plant glutathione S-transferases are an ancient protein superfamily having antioxidant activity. These proteins are primarily involved in diverse plant functions such as...     

Serum glucose-regulated protein 78 (GRP78) levels in COVID-19-associated mucormycosis: results of a case–control study

Mycopathologia - In experimental models, the expression of glucose-regulated protein 78 (GRP78) in endothelial cells played a role in the pathogenesis of mucormycosis. However, the role of GRP78 in...     

A decision support tool for integrated fisheries bycatch management

Reviews in Fish Biology and Fisheries - Participatory decision tools enable stakeholders to reconcile conflicting natural resources management objectives. Fisheries targeting highly productive...     

Statistical modelling and optimization of substrate composition for bacterial growth and cadmium removal using response surface methodology

In this study, substrate composition was optimized for the growth of Achromobacter xyloxidans and biosorption of Cd(II) from aqueous solution. Response surface methodology (RSM) was used to investigate the function of three independent operating variables, namely, peptone (2.5-10 g/L), beef extract (2.5-5.0 g/L) and incubation time (24-96 h), on dependent variables, i.e. sorption of Cd(II) ions, protein content and biomass growth of A. xyloxidans. The maximum Cd(II) removal efficiency of 69.2%, protein content 1.9 mg/L and growth 0.354 optical density was found at optimal conditions of peptone 10 g/L, incubation time 60 h and beef extract 2.5 g/L. The significance of independent variables and interactions between variables were tested by means of the analysis of variance (ANOVA) with 95% confidence limits and values of “Prob > F” less than 0.0500 indicate that model terms are significant. Fourier transfer infrared (FTIR) analysis was used to investigate sorption mechanism and involved functional groups in Cd(II) binding.