Outsider to insider: resetting the natural host niche of commensal E. coli K-12

The status of E. coli K-12 as an exclusively non-invasive, non-pathogenic bacterium has almost been incontrovertible. Our recent finding that a mutation in one of its main architectural protein, HU, converts E. coli K-12 to an actively invasive form suggests that gaining host cell entry might be an expedient survival tactic for traditional commensals during certain altered host conditions. The mutant E. coli (SK3842) exhibits properties usually associated with pathogenic bacteria: host cell invasion, phagosomal disruption and intracellular replication. However, unlike the situation with some pathogens, internalized SK3842 imparts anti-apoptotic and cyto-protective effects rather than lethality on the host cell, both in vitro and in vivo. Here, we show that SK3842 also provides colonization resistance against other invasive pathogens--a trait not shared by the parental commensal strain. Thus, the altered lifestyle of SK3842 encompasses characteristics both from traditional pathogens as well as beneficial probiotic strains.     

The abrogation of condensin function provides independent evidence for defining the self-renewing population of pluripotent stem cells

Heterogeneity of planarian stem cells has been categorised on the basis of single cell expression analyses and subsequent experiments to demonstrate lineage relationships. Some data suggest that despite heterogeneity in gene expression amongst cells in the cell cycle, in fact only one sub-population, known as sigma neoblasts, can self-renew. Without the tools to perform live in vivo lineage analysis, we instead took an alternative approach to provide independent evidence for defining the self-renewing stem cell population. We exploited the role of highly conserved condensin family genes to functionally assay neoblast self-renewal properties. Condensins are involved in forming properly condensed chromosomes to allow cell division to proceed during mitosis, and their abrogation inhibits mitosis and can lead to repeated endoreplication of the genome in cells that make repeated attempts to divide. We find that planarians possess only the condensin I complex, and that this is required for normal stem cell function. Abrogation of condensin function led to rapid stem cell depletion accompanied by the appearance of ‘giant’ cells with increased DNA content. Using previously discovered markers of heterogeneity we show that enlarged cells are always from the sigma-class of the neoblast population and we never observe evidence for endoreplication for the other neoblast subclasses. Overall, our data establish that condensins are essential for stem cell maintenance and provide independent evidence that only sigma-neoblasts are capable of multiple rounds of cell division and hence self-renewal.     

Estimating Mammalian Abundance Using Camera Traps in the Tropical Forest of Similipal Tiger Reserve,Odisha, India

Knowledge on the occurrence and distribution of species is crucial for designing and evaluating conservation strategies within a geographical region. Similipal Tiger Reserve though confined to a small area needs information on the diversity and abundance of mammalian fauna to ensure conservation of tiger. Thus, we aimed to assess the diversity and abundance of medium to large sized mammals in Similipal Tiger Reserve by using remotely triggered camera traps. A total of 6413 camera trap days at 187 trap stations were deployed from November 2012 to July 2013 to estimate the status of mammal. We obtained 3763 independent photographs and detected 24 species of mammals. The relative abundance index of each mammalian species was calculated. Leopard (Panthera pardus) was the most abundant carnivore while barking deer (Muntiacus muntjac) was the most abundant prey. Anthropogenic activities like hunting, livestock grazing and free ranging domestic dogs were found to be the detrimental factors for the existing mammalian species. These activities should be addressed through conservation and development perception with an interdisciplinary approach, incorporating social and ecological components cautiously.     

Effect of long-term treatment of norethisterone (a progestogen-only contraceptive) on salivary gland activity of the cycling albino rat

Effect of long-term treatment of norethisterone (a progestogen-only contraceptive) on the salivary glands of the cycling albino rats was evaluated from histomorphic and karyokinetic standpoints. Norethisterone increased concentration of zymogen granules in the serous acini and also of mucoid material in the mucous-containing acini in the submaxillary gland. In the parotid gland, the acini were hypertrophied, accompanied by cytoplasmic degranulation. In addition, the mitotic cells were seen in both the glands after the treatment. It is suggested that norethisterone perhaps stimulates the salivary gland activity of the rats.     

Structure of carbohydrate chains of a high-molecular-weight pulmonary glycoprotein

A human, alveolar glycoprotein having an apparent mol. wt. of 250 000 gave two major glycopeptide fractions (I and II) by Pronase digestion, followed by gel filtration, DEAE-cellulose column chromatography, paper chromatography, and paper electrophoresis. Glycopeptide I contained d-galactose, d-mannose, 2-acetamido-2-deoxy-d-glucose, and N-acetylneuraminic acid in the molar ratio of 2:3:4:1, whereas these sugars were present in Glycopeptide II in the molar ratio of 2:3:4:2.l-Fucose was present only in Glycopeptide II at a concentration of one l-fucose per three d-mannose residues. In both glycopeptides, 2-acetamido-2-deoxy-d-glucose was linked to an asparagine residue of the peptide chain. Based on the results of alkaline borohydride treatment, periodate oxidation, methlylation analysis, and sequential glycosidase degradation of the glycopeptides, tentative structures are proposed for both glycopeptides.     

Taximetrics study of varieties of Bidens pilosa species

Hooker (1882) has reported three varieties in Bidens pilosa species i. e., pilosa Proper, Linn. bipinnata Linn. and decomposita Wall. Clarke (1876) has included var. decomposita into B. pilosa proper. Taxonomic position of varieties pilosa proper and bipinnata is much confusing in literature. Babu (1977)has raised varieties pilosa proper and bipinnata as distinct species level into B. pilosa and B. bipinnata respectively. The present taximetric study also justified the distinction of these varieties as specific level. Hooker has reported three varieties of species B. pilosa i.e., pilosa proper Linn., bipinnata Linn., and decomposita Wall. from the Himalayan region of India. Clarke (1876) has included var. decomposita into B. pilosa proper. During taxonomic work on the family Compositae author has found that taxonomic position of var. pilosa proper and bipinnata is much confusing in literature. Babu (1977) has raised varieties pilosa proper and bipinnata as distinct species level. Looking to this discretion, it was de-eided to use taximetrics in interpreting taxonomic status of these taxa.