Antiapoptotic role of S-adenosyl-l-methionine against hydrochloric acid induced cell death in Saccharomyces cerevisiae

Exposure of stationary phase cells of Saccharomyces cerevisiae to 10 mM HCl (pH approximately 2) resulted in cell death as a function of time (up to 6 h) with most (about 40%-65%) of the cells showing apoptotic features including chromatin condensation along the nuclear envelope, exposure of phosphatidylserine on the outer leaflet of cytoplasmic membrane, and DNA fragmentation. During the first 2 h of acid exposure there was an increase in reactive oxygen species (ROS) level inside cells, with subsequent elevation in the level of lipid peroxidation and decrease in reducing equivalents culminating in loss of mitochondrial membrane potential (DeltaPsi(m)). An initial (1 h) event of mitochondrial hyper-polarization with subsequent elevation of ROS level of the acid treated cells was also observed. S-adenosyl-l-methionine (AdoMet; 1 mM) treatment increased the cell survival of the acid stressed cells. It partially scavenged the increased intracellular ROS level by supplementing glutathione through the transsulfuration pathway. It also inhibited acid mediated lipid peroxidation, partially recovered acid evoked loss of DeltaPsi(m) and protected the cells from apoptotic cell death. S-adenosyl di-aldehyde, an indirect inhibitor of the AdoMet metabolic pathway, increased mortality of the acid treated cells. Incubation of acid stressed cells with the antioxidant, N-acetyl-cysteine (1 mM), decreased the cellular mortality, but the same concentration of AdoMet offered more protection by scavenging the free radicals. The ability of AdoMet to scavenge ROS mediated apoptosis may be an important function of this molecule in responding to cellular stress. The study could open a new avenue for detailed investigation on the curative potential of AdoMet against gastric ulcer.     

Regulation of Notch signalling by non-visual beta-arrestin

Signalling activity of the Notch receptor, which plays a fundamental role in metazoan cell fate determination, is controlled at multiple levels. We uncovered a Notch signal-controlling mechanism that depends on the ability of the non-visual beta-arrestin, Kurtz (Krz), to influence the degradation and, consequently, the function of the Notch receptor. We identified Krz as a binding partner of a known Notch-pathway modulator, Deltex (Dx), and demonstrated the existence of a trimeric Notch-Dx-Krz protein complex. This complex mediates the degradation of the Notch receptor through a ubiquitination-dependent pathway. Our results establish a novel mode of regulation of Notch signalling and define a new function for non-visual beta-arrestins.     

Modeling the interactions of Lactobacillus curvatus colonies in solid medium: consequences for food quality and safety

The growth process of Lactobacillus curvatus colonies was quantified by a coupled growth and diffusion equation incorporating a volumetric rate of lactic acid production. Analytical solutions were compared to numerical ones, and both were able to predict the onset of interaction well. The derived analytical solution modeled the lactic acid concentration profile as a function of the diffusion coefficient, colony radius, and volumetric production rate. Interaction was assumed to occur when the volume-averaged specific growth rate of the cells in a colony was 90% of the initial maximum rate. Growth of L. curvatus in solid medium is dependent on the number of cells in a colony. In colonies with populations of fewer than 10(5) cells, mass transfer limitation is not significant for the growth process. When the initial inoculation density is relatively high, colonies are not able to grow to these sizes and growth approaches that of broth cultures (negligible mass transfer limitation). In foods, which resemble the model solid system and in which the initial inoculation density is high, it will be appropriate to use predictive models of broth cultures to estimate growth. For a very low initial inoculation density, large colonies can develop that will start to deviate from growth in broth cultures, but only after large outgrowth.     

Isolation, identification and characterization of secretory proteins of IVMFC embryos and blood circulation of estrus and early pregnant goat

The aim of the present study was to isolate, identify and characterize the secretory proteins of IVM oocytes and IVMFC embryos to evaluate its immunogenecity. and identify of such proteins if any, in blood circulation of estrus and early pregnant goats. Oocytes were matured in TCM-199 with 1 microg/ml, estradiol-17beta; 0.5 microg/ml, FSH; 100 IU/ml, LH and 10% FCS on granulosa cell monolayer. After 18 hr of maturation, oocytes were further cultured in maturation medium containing 3 mg/ml polyvinyl alcohol (PVA) without serum and BSA for 12 hr and medium was collected. The IVF embryos of 4-8 cell stage were cultured in medium containing PVA without serum and BSA. Embryo culture medium was collected after 24 hr of culture and was pooled. The proteins were analyzed on SDS-PAGE (12.5%). Four secretory proteins of oocytes with approximately molecular weight of 45, 55, 65 and 95 kDa and three secretory proteins of embryos 45, 55 and 65 kDa were obtained on SDS-PAGE in silver staining. The protein profile of midluteal, estrus and early pregnant goat serum was similar and no variation was observed among the proteins on SDS-PAGE. Two secretory proteins of 55 and 65 kDa of both IVM oocytes and IVMFC embryos were observed on Western analysis. None of such proteins was observed in midluteal, estrus and early pregnant goat serum on western blotting. It can be concluded that IVM oocytes and IVMFC embryos secrete proteins in medium and two of them can develop antibody. The proteins secreted from embryos till morula stage was similar to that of oocytes. None of these oocyte/embryo released proteins were observed in blood circulation of estrus and early pregnant goats.     

Molecular identification of three Ompok species using mitochondrial COI gene

A DNA-based barcode identification system that is applicable to all animal species will provide a simple, universal tool for the identification of fish species. The barcode system is based on sequence diversity in subunit 1 cytochrome c oxidase (COI) gene. Identification and characterization of fish species based on morphological characters are sometimes found to be erroneous and environmentally affected. There are no studies on the genus Ompok in India at molecular level and species identification of the Ompok is usually carried out through morphological features. A total of 106 samples from three species Ompok pabda, O. pabo and O. bimaculatus were collected from eight sampling sites of seven Indian rivers. One hundred and six sequences were generated from COI region of three Ompok species and 21 haplotypes were observed. The sequence analysis of COI gene revealed three genetically distinct Ompok species and exhibited identical phylogenetic resolution among them. The partial COI gene sequence can be used as a diagnostic molecular marker for identification and resolution of taxonomic ambiguity of Ompok species.     

Effect of substrate and IPTG concentrations on the burden to growth of <Emphasis Type="Italic">Escherichia coli</Emphasis> on glycerol due to the expression of Lac proteins

Expression of proteins unneeded for growth diverts cellular resources from making necessary protein and leads to a reduction in the growth rate of an organism. This reduction in growth rate is termed as cost. Cost plays an important role in determining the selected expression of a protein in a particular environment. Characterization of cost is important in biotechnology industries where microorganisms are used to produce foreign proteins. We have used the lactose system in Escherichia coli to quantify the cost of growth on glycerol in the presence of isopropyl-β-d-thiogalactopyranoside (IPTG), an inducer of the lactose system. The effect of the concentration of the carbon source, glycerol, and the inducer of Lac enzymes, IPTG, is studied. The results show that the cost is dependent on the glycerol concentration with a decreasing trend with increasing concentration of glycerol. Also as expected, the cost increases and saturates at a higher concentration of IPTG. The studies also demonstrate that the cost is higher in early exponential phase relative to late exponential phase during the growth as has been reported in the literature. Hill equation fit yielded a typical Monod-type expression for growth on glycerol with and without IPTG. An apparent half-saturation constant was defined which was used to characterize the burden on growth due to protein expression.     

Ultrathin Bilayer of Graphite/SiO2 as Solid Interface for Reviving Li Metal Anode

Lithium metal anodes are expected to drive practical applications that require high energy‐density storage. However, the direct use of metallic lithium causes safety concerns, low rate capabilities, and poor cycling performance due to unstable solid electrolyte interphase (SEI) and undesired lithium dendrite growth. To address these issues, a radio frequency sputtered graphite‐SiO₂ ultrathin bilayer on a Li metal chips is demonstrated, for the first time, as an effective SEI layer. This leads to a dendrite free uniform Li deposition to achieve a stable voltage profile and outstanding long hours plating/stripping compared to the bare Li. Compared to a bare Li anode, the graphite‐SiO₂ bilayer modified Li anode coupled with lithium nickel cobalt manganese oxide cathode (NMC111) and lithium titanate shows improved capacity retention, higher capacity at higher rates, longer cycling stability, and lower voltage hysteresis. Graphite acts as an electrical bridge between the plated Li and Li electrode, which lowers the impedance and buffers the volume expansion during Li plating/stripping. Adding an ultrathin SiO₂ layer facilitates Li‐ion diffusion and lithiation/delithiation, provides higher electrolyte affinity, higher chemical stability, and higher Young's modulus to suppress the Li dendrite growth.     

Homing of radiolabelled recombinant interleukin-2 activated natural killer cells and their efficacy in adoptive immunotherapy against murine fibrosarcoma

Natural killer (NK) cells are spontaneously cytotoxic against tumour target cells. Their number was found to be four times more in the spleen of tumour-bearing Swiss albino mice. After activation with recombinant interleukin-2 (rIL-2), NK cells were tested and found to seek out the tumour site when injected intravenously in tumour-bearing mice. Their potential for fighting tumours in vivo was further seen following adoptive transfer of rIL-2 activated NK (A-NK) cells in tumour-bearing mice. After surgical removal of tumour load, adoptive transfer of A-NK cells inhibited tumour recurrence in 92.3%cases, thereby suggesting the use of this protocol for therapeutic purposes to obtain a better outcome.     

Increasing signs of degradation of shallow water coral reefs due to repeated bleaching and spatial competition among benthic substrates

Wetlands Ecology and Management - Summer bleaching of corals has been prevalent in the coastal waters of India in recent years before the onset of monsoon. Repeated bleaching of shallow water...