Genome sequencing of <Emphasis Type="Italic">Pediococcus acidilactici</Emphasis> (NRCC1), a novel isolate from dromedary camel (<Emphasis Type="Italic">Camelus dromedarius</Emphasis>) rumen fluid

The lactic acid bacterium Pediococcus acidilactici has recently been reported to help in treating constipation, diarrhea, relieving stress, and enhancing growth rate and immune response in humans, birds, fishes, and small animals. In the present study, we sequenced and analyzed the whole genome of P. acidilactici NRCC1, a novel isolate from rumen fluid of dromedary camel (Camelus dromedarius). The genome of P. acidilactici NRCC1 was assembled into 60 contigs, comprising 1,785,679 bp and 42.5% GC content. The 1705 CDS were predicted and annotated using the RAST server. The genome encodes numerous enzymes for utilization of different carbohydrates. It also harbors genes for antibiotic biosynthesis and many others which might confer probiotic properties. The comparative genome analysis with P. acidilactici DSM 20284 revealed some unique features in P. acidilactici NRCC1. Thus, the genome sequencing of P. acidilactici NRCC1 has opened up new horizons for further research in animal probiotics and feed supplements.     

Endorsing cellular competitiveness in aberrant epithelium of oral submucous fibrosis progression: neighbourhood analysis of immunohistochemical attributes

Epithelial abnormality during the transformation of oral submucous fibrosis (OSF) into oral squamous cell carcinoma has been well studied and documented. However, the differential contribution of atrophy and hyperplasia for malignant potentiality of OSF is yet to be resolved. Existing diagnostic conjectures lack precise diagnostic attributes which may be effectively resolved by substantiation of specific molecular pathology signatures. Present study elucidates existence of cellular competitiveness in OSF conditions using computer-assisted neighbourhood analysis in quantitative immunohistochemistry (IHC) framework. The concept of field cancerization was contributory in finding correspondence among neighbouring cells of epithelial layers with reference to differential expression of cardinal cancer-related genes [c-Myc (oncogene), p53 (tumour suppressor), and HIF-1α (hypoxia regulator)] which are known to be important sensors in recognizing cellular competitive interface. Our analyses indicate that different states of OSF condition may be associated with different forms of competitiveness within epithelial neighbouring cells which might be responsible to shape the present and future of the pre-malignant condition. Analytical findings indicated association of atrophic epithelium with stress-driven competitive environment having low c-Myc, high-p53, and stable HIF-1α (the looser cells) which undergo apoptosis. Whereas, the cells with high c-Myc⁺ (winner cells) give rise to hyperplastic epithelium via possible mutation in p53. The epithelial dysplasia plausibly occurs due to clonal expansion of c-Myc and p53 positive supercompetitor cells. Present study proposes quantitative IHC along with neighbourhood analysis which might help us to dig deeper on to the interaction among epithelial cell population to provide a better understanding of field cancerization and malignant transformation of pre-malignancy.     

Mechanisms of sodium/calcium selectivity in sodium channels probed by cysteine mutagenesis and sulfhydryl modification.

A conserved lysine residue in the "P loop" of domain III renders sodium channels highly selective. Conversion of this residue to glutamate, to mimic the homologous position in calcium channels, enables Ca2+ to permeate sodium channels. Because the lysine-to-glutamate mutation converts a positively charged side chain to a negative one, it has been proposed that a positive charge at this position suffices for Na+ selectivity. We tested this idea by converting the critical lysine to cysteine (K1237C) in mu 1 rat skeletal sodium channels expressed in Xenopus oocytes. Selectivity of the mutant channels was then characterized before and after chemical modification to alter side-chain charge. Wild-type channels are highly selective for Na+ over Ca2+ (PCa/PNa < 0.01). The K1237C mutation significantly increases permeability to Ca2+ (PCa/PNa = 0.6) and Sr2+. Analogous mutations in domains I (D400C), II (E755C), and IV (A1529C) did not alter the selectivity for Na+ over Ca2+, nor did any of the domain IV mutations (G1530C, W1531C, and D1532C) that are known to affect monovalent selectivity. Interestingly, the increase in permeability to Ca2+ in K1237C cannot be reversed by simply restoring the positive charge to the side chain by using the sulfhydryl modifying reagent methanethiosulfonate ethylammonium. Single-channel studies confirmed that modified K1237C channels, which exhibit a reduced unitary conductance, remain permeable to Ca2+, with a PCa/PNa of 0.6. We conclude that the chemical identity of the residue at position 1237 is crucial for channel selectivity. Simply rendering the 1237 side chain positive does not suffice to restore selectivity to the channel.     

Molecular motions within the pore of voltage-dependent sodium channels.

The pores of ion channel proteins are often modeled as static structures. In this view, selectivity reflects rigidly constrained backbone orientations. Such a picture is at variance with the generalization that biological proteins are flexible, capable of major internal motions on biologically relevant time scales. We tested for motions in the sodium channel pore by systematically introducing pairs of cysteine residues throughout the pore-lining segments. Two distinct pairs of residues spontaneously formed disulfide bonds bridging domains I and II. Nine other permutations, involving all four domains, were capable of disulfide bonding in the presence of a redox catalyst. The results are inconsistent with a single fixed backbone structure for the pore; instead, the segments that line the permeation pathway appear capable of sizable motions.     

Rhamnolipid biosurfactants: evolutionary implications,applications and future prospects from untapped marine resource

Rhamnolipid-biosurfactants are known to be produced by the genus Pseudomonas, however recent literature reported that rhamnolipids (RLs) are distributed among diverse microbial genera. To integrate the evolutionary implications of rhamnosyl transferase among various groups of microorganisms, a comprehensive comparative motif analysis was performed amongst bacterial producers. Findings on new RL-producing microorganism is helpful from a biotechnological perspective and to replace infective P. aeruginosa strains which ultimately ensure industrially safe production of RLs. Halotolerant biosurfactants are required for efficient bioremediation of marine oil spills. An insight on the exploitation of marine microbes as the potential source of RL biosurfactants is highlighted in the present review. An economic production process, solid-state fermentation using agro-industrial and industrial waste would increase the scope of biosurfactants commercialization. Potential and prospective applications of RL-biosurfactants including hydrocarbon bioremediation, heavy metal removal, antibiofilm activity/biofilm disruption and greener synthesis of nanoparticles are highlighted in this review.     

The co-chaperone CHIP is induced in various stresses and confers protection to cells

The C-terminus of Hsp70 interacting protein (CHIP) is being considered to be a cellular quality control E3 ubiquitin ligase because of its ability to degrade misfolded proteins in association with heat shock chaperones. The neuroprotective role of CHIP also has been implicated in several familial neurodegenerative diseases including polyglutamine diseases. However, the regulation of the expression of CHIP under different stress conditions and its protective role thereon is unknown. Here we have shown that the mRNA level of CHIP is significantly increased in the cells exposed to oxidative, endoplasmic reticulum and proteasomal stress. CHIP also protected from various stress-induced cell death. Finally, we have demonstrated upregulation of CHIP mRNA levels in the expanded polyglutamine protein expressing cells. Our result suggests that the upregulation of CHIP under various stress environments is an adaptive response of the cells to deal with the excess burden of misfolded protein.     

The DIF1 gene of Arabidopsis is required for meiotic chromosome segregation and belongs to the REC8/RAD21 cohesin gene family

Cohesins are a group of conserved proteins responsible for cohesion between replicated sister chromatids during mitosis and meiosis and which are implicated in double-strand break repair and meiotic recombination. We describe here the identification and characterisation of an Arabidopsis gene - DETERMINATE, INFERTILE1 (DIF1), which is a homolog of the Schizosaccharomyces pombe REC8/RAD21 cohesin genes, and is essential for meiotic chromosome segregation. Five independent alleles of the DIF1 gene were isolated by transposon mutagenesis, and the mutants show complete male and female sterility. Pollen mother cells (PMCs) of dif1 mutants show multiple meiotic defects which are represented by univalent chromosomes and chromosome fragmentation at metaphase I, and acentric fragments and chromatin bridges in meiosis I and II. Consequently, chromosome segregation is strongly affected, resulting in meiotic products of uneven size, shape and of variable ploidy. The similarities in phenotype, and the sequence homology between DIF1 and the REC8/RAD21 cohesins suggests that cohesin function is largely conserved between eukaryotes and highlights the essential role cohesins play in plant meiosis.