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.     

Oil palm (Elaeis guineensis) protoplasts: isolation, culture and microcallus formation

Procedures are deseribed for the efficient isolation of protoplasts from a variety of oil palm (Elaeis guineensis Jacq.) tissues. Various factors including donor source, composition of enzyme mixture and culture medium affected the yield and viability of the protoplasts Polyembryogenic cultures of oil palm were the most suitable starting material in terms of yield, viability and metabolic competence. Pectolyase Y-23 in association with cellulase and hemicellulase was required for the efficient release of protoplasts from the oil palm tissues. Limited cell division to form microcallus was observed at very low frequency (<0.01%) when glutathione and catalase were incorporated in the culture medium.Abbreviations 2,4-d dichlorophenoxyacetic acid - DTT dithiothreitol - MES 2[N-morpholino] ethanesulphonic acid - NAA 1-naphthalene acetic acid - PVP polyvinylpyrrolidone     

Vector competence ofRhipicephalus sanguineus andDermacentor variabilis for American isolates ofBabesia gibsoni

To determine the identity of the tick vector of enzooticBabesia gibsoni in California, two common ixodid ticks were allowed to engorge uponB. gibsoni infected dogs. Sporozoites were observed in the salivary glands of prefed nymphalRhipicephalus sanguineus ticks that fed as larvae onB. gibsoni-infected dogs. A higher proportion (31%) of nymphal ticks that prefed on an uninfected dog for 48 hours contained sporozoites in their salivary glands than did ticks which had fed for 24 hours (13%). Sporozoites were not observed in the salivary glands of prefedR. sanguineus nymphs which were derived from the eggs of adult females that fed on an infected dog, in adults that were fed as nymph on an infected dog, or in the nymphal and adult uninfected controls.Dermacentor variabilis ticks appeared not to become infected. Although attempts to transmitB. gibsoni to susceptible, splenectomized dogs were unsuccessful,R. sanguineus would appear to be the most likely tick vector to maintain this piroplasm in California. This study was supported by grants from the Companion Animal Disease Laboratory, School of Veterinary Medicine, University of California, Davis.     

Enzymatic characterization of Catalase from Bacillus anthracis and prediction of critical residues using information theoretic measure of Relative Entropy

In order to cope up with the reactive oxygen species (ROS) generated by host innate immune response, most of the intracellular organisms express Catalase for the enzymatic destruction/detoxification of hydrogen peroxide, to combat its deleterious effects. Catalase thus, scavenges ROS thereby playing a pivotal role in facilitating the survival of the pathogen within the host, and thus contributes to its pathogenesis. Bacillus anthracis harbors five isoforms of Catalase, but none of them has been studied so far. Thus, this study is the first attempt to delineate the biochemical and functional characteristics of one of the isoforms of Catalase (Cat1.4) of B. anthracis, followed by identification of residues critical for catalysis. The general strategy used, so far for mutational analysis in Catalases is structure based, i.e. the residues in the vicinity of heme were mutated to decipher the enzymatic mechanism. However, in the present study, protein sequence analysis was used for the prediction of catalytically important residues of Catalase. Essential measures were adopted to ensure the accuracy of predictions like after retrieval of well-annotated sequences from the database with EC 1.11.1.6, preprocessing was done to remove irrelevant sequences. The method used for multiple alignment of sequences, was guided by structural alignment and thereafter, an information theoretic measure, Relative Entropy was used for the critical residue prediction. By exploiting this strategy, we identified two previously known essential residues, H55 and Y338 in the active site which were demonstrated to be crucial for the activity. We also identified six novel crucial residues (Q332, Y117, H215, W257, N376 and H146) located distantly from the active site. Thus, the present study highlights the significance of this methodology to identify not only those crucial residues which lie in the active site of Catalase, but also the residues located distantly.     

Histone crosstalk directed by H2B ubiquitination is required for chromatin boundary integrity

Genomic maps of chromatin modifications have provided evidence for the partitioning of genomes into domains of distinct chromatin states, which assist coordinated gene regulation. The maintenance of chromatin domain integrity can require the setting of boundaries. The HS4 insulator element marks the 3' boundary of a heterochromatin region located upstream of the chicken β-globin gene cluster. Here we show that HS4 recruits the E3 ligase RNF20/BRE1A to mediate H2B mono-ubiquitination (H2Bub1) at this insulator. Knockdown experiments show that RNF20 is required for H2Bub1 and processive H3K4 methylation. Depletion of RNF20 results in a collapse of the active histone modification signature at the HS4 chromatin boundary, where H2Bub1, H3K4 methylation, and hyperacetylation of H3, H4, and H2A.Z are rapidly lost. A remarkably similar set of events occurs at the HSA/HSB regulatory elements of the FOLR1 gene, which mark the 5' boundary of the same heterochromatin region. We find that persistent H2Bub1 at the HSA/HSB and HS4 elements is required for chromatin boundary integrity. The loss of boundary function leads to the sequential spreading of H3K9me2, H3K9me3, and H4K20me3 over the entire 50 kb FOLR1 and β-globin region and silencing of FOLR1 expression. These findings show that the HSA/HSB and HS4 boundary elements direct a cascade of active histone modifications that defend the FOLR1 and β-globin gene loci from the pervasive encroachment of an adjacent heterochromatin domain. We propose that many gene loci employ H2Bub1-dependent boundaries to prevent heterochromatin spreading.     

Morphological parallelism of sympatric cave-dwelling microsnails of the genus Georissa at Mount Silabur,Borneo (Gastropoda,Neritimorpha, Hydrocenidae)

Parallel evolution in phenotype may result when closely related taxa are adapting in the face of similar ecological pressures. Here, we discuss possible parallelism in shell morphology in the context of the microgeographic phylogeography of two conchologically distinct sympatric hydrocenid snails inhabiting a limestone outcrop and its cave system, Georissa pyrrhoderma and Georissa silaburensis, respectively, at Mount Silabur in Sarawak, Malaysian Borneo. Our results show a certain degree of morphological parallelism of a third, possibly new, cryptic Georissa species within the same cave that strongly diverged from its above-ground sister species, G. pyrrhoderma. We found that both sympatric cave species have shifted from a more sculptured, conical shell toward a broader, less sculptured form.     

Silencing of ZFP36L2 increases sensitivity to temozolomide through G2/M cell cycle arrest and BAX mediated apoptosis in GBM cells

Molecular Biology Reports - Despite the advancements in primary brain tumour diagnoses and treatments, the mortality rate remains high, particularly in glioblastoma (GBM). Chemoresistance,...     

Identification of Alkaloid Compounds Arborinine and Graveoline from Ruta angustifolia (L.) Pers for their Antifungal Potential against Isocitrate lyase (ICL1) gene of Candida albicans

Mycopathologia - Candida albicans has been reported globally as the most widespread pathogenic species contributing candidiasis from superficial to systemic infections in immunocompromised...