Isolation and screening of potential actinobacteria for rapid composting of rice straw

Rice straw is produced as a by-product from rice cultivation, which is composed largely of lignocellulosic materials amenable to general biodegradation. Lignocellulolytic actinobacteria can be used as a potential agent for rapid composting of bulky rice straw. Twenty-five actinobacteria isolates were isolated from various in situ and in vitro rice straw compost sources. Isolates A2, A4, A7, A9 and A24 were selected through enzymatic degradation of starch, cellulose and lignin followed by the screening for their adaptability on rice straw powder amended media. The best adapted isolate (A7) was identified as Micromonospora carbonacea. It was able to degrade cellulose, hemicelluloses and carbon significantly (P ≤ 0.05) over the control. C/N ratio was reduced to 18.1 from an initial value of 29.3 in 6 weeks of composting thus having the potential to be used in large scale composting of rice straw.     

Selective antagonism of calcitonin-induced osteoclastic quiescence (Q effect) by human calcitonin gene-related peptide-(Val8Phe37)

Exposure of isolated rat osteoclasts to calcitonin (CT) leads to an abrupt cessation of cell motility (Q effect) followed by cell retraction (R effect). We have previously shown that these effects are mediated by two G proteins that appear to activate separate post-receptor pathways. The present study demonstrates that the Q but not the R effect of CT (0.006 microM) is abolished in the presence of human calcitonin gene-related peptide (CGRP)-(Val8Phe37) (0.5 microM), a fragment analogue of human CGRP. This selective antagonism suggests that the Q effect could result from an action of CT upon a site that is distinct from that producing the R effect. The former site ('amylin site') also appears to interact with related peptides, amylin and CGRP, whilst the latter site ('CT site') specifically interacts with CT.     

Protection of Human Pancreatic Islets from Lipotoxicity by Modulation of the Translocon

Type 2 diabetes is characterized by peripheral insulin resistance and pancreatic beta cell dysfunction. Elevated free fatty acids (FFAs) may impair beta cell function and mass (lipotoxicity). Altered calcium homeostasis may be involved in defective insulin release. The endoplasmic reticulum (ER) is the major intracellular calcium store. Lipotoxicity induces ER stress and in parallel an ER calcium depletion through unknown ER calcium leak channels. The main purposes of this study is first to identify one of these channels and secondly, to check the opportunity to restore beta cells function (i.e., insulin secretion) after pharmacological inhibition of ER calcium store depletion. We investigated the functionality of translocon, an ER calcium leak channel and its involvement on FFAs-induced alterations in MIN6B1 cells and in human pancreatic islets. We evidenced that translocon acts as a functional ER calcium leak channel in human beta cells using anisomycin and puromycin (antibiotics), respectively blocker and opener of this channel. Puromycin induced a significant ER calcium release, inhibited by anisomycin pretreatment. Palmitate treatment was used as FFA model to induce a mild lipotoxic effect: ER calcium content was reduced, ER stress but not apoptosis were induced and glucose induced insulin secretion was decreased in our beta cells. Interestingly, translocon inhibition by chronic anisomycin treatment prevented dysfunctions induced by palmitate, avoiding reticular calcium depletion, ER stress and restoring insulin secretion. Our results provide for the first time compelling evidence that translocon actively participates to the palmitate-induced ER calcium leak and insulin secretion decrease in beta cells. Its inhibition reduces these lipotoxic effects. Taken together, our data indicate that TLC may be a new potential target for the treatment of type 2 diabetes.     

Existence of a Novel Hemagglutinin Having No Protease Activity in Vibrio mimicus

The protease elaborated by Vibrio mimicus is known to possess hemagglutinating ability to chicken erythrocytes, the well-known HA/protease. A non-protease hemagglutinin (HA) with strong agglutinating ability towards rabbit erythrocytes was obtained from 32 hr culture supernatant of a pathogenic environmental strain of V. mimicus. This HA (V. mimicus HA: VMHA) appeared stable at relatively higher temperature and agglutinated the erythrocytes from rabbit, guinea pig and mouse but not the erythrocytes from chicken, bovine, horse and sheep. Simple sugars, metal ions and chelating agents failed to inhibit the activity of VMHA. The activity of VMHA was found to be sensitive to digestion by proteolytic enzymes including HA/protease. These results provide evidence for the existence of novel HA other than HA/protease in V. mimicus.     

Luciferase-based reporter system for in vitro evaluation of elongation rate and processivity of ribosomes

The elongation step of translation is a key contributor to the abundance, folding and quality of proteins and to the stability of mRNA. However, control over translation elongation has not been thoroughly investigated. In this study, a Renilla–firefly luciferase fusion reporter system was further developed to investigate the in vitro elongation rate and processivity of ribosomes independent of the initiation and termination steps. The reporter mRNA was constructed to contain a single ORF encoding in-frame Renilla luciferase, a specific domain moiety and firefly luciferase. Such a reporter structure enables the quantitative and individual evaluation of the synthesis of a specific domain. As a proof of principle, the synthesis of three protein domains of different lengths and structures was analyzed. Using a cell-free translation assay, both the elongation rate and processivity of ribosomes were shown to vary depending on the domain synthesized. Additionally, a stalling sequence consisting of ten rare arginine codons notably reduced the elongation rate and the processivity of the ribosomes. All these results are consistent with the previously known dynamics of elongation in vivo. Overall, the methodology presented in this report provides a framework for studying aspects that contribute to the elongation step of translation.     

Population Dynamics of the Root-Knot Nematode Meloidogyne Triticoryzae under Five Rice-Based Cropping Systems

Population dynamics of M. triticoryzae in five rice-based cropping systems have revealed that rice was the main host. Most of the population growth which contributed to the peak population density in September occurred in the rice crop. The other crops in the Rabi and summer seasons had a profound influence on the height of the peak in the succeeding rice crop. Some level of reproduction occurred in wheat, greengram and berseem in Rabi which contributed to relatively higher equilibrium densities. The potato variety Pusa Bahar increased the population density while Pusa Badshah decreased it. The lower temperature during the Rabi season also limited the rate of population growth. The incorporation of organic matter into the soil, either as crop residues of greengram or berseem, reduced the population growth of M. triticoryzae .