Occurrence of Horizontal Gene Transfer of PIB-type ATPase Genes among Bacteria Isolated from the Uranium Rich Deposit of Domiasiat in North East India

Uranium (U) tolerant aerobic heterotrophs were isolated from the subsurface soils of one of the pre-mined U-rich deposits at Domiasiat located in the north-eastern part of India. On screening of genomic DNA from 62 isolates exhibiting superior U and heavy metal tolerance, 32 isolates were found to be positive for P_IB-type ATPase genes. Phylogenetic incongruence and anomalous DNA base compositions revealed the acquisition of P_IB-type ATPase genes by six isolates through horizontal gene transfer (HGT). Three of these instances of HGT appeared to have occurred at inter-phylum level and the other three instances indicated to have taken place at intra-phylum level. This study provides an insight into one of the possible survival strategies that bacteria might employ to adapt to environments rich in uranium and heavy metals.     

A mini-Tn5-derived transposon with reportable and selectable markers enables rapid generation and screening of insertional mutants in Gram-negative bacteria

We re-engineered a classic tool for mutagenesis and gene expression studies in Gram-negative bacteria. Our modified Tn5-based transposon contains multiple features that allow rapid selection for mutants, direct quantification of gene expression and straightforward cloning of the inactivated gene. The promoter-less gfp-km cassette provides selection and reporter assay depending on the activity of the promoter upstream of the transposon insertion site. The cat gene facilitates positive antibiotic selection for mutants, while the narrow R6Kγ replication origin forces transposition in recipient strains lacking the pir gene and enables cloning of the transposon flanked with the disrupted gene from the chromosome. The suicide vector pCKD100, a plasmid that could be delivered into recipient cells through biparental mating or electroporation, harbours the modified transposon. We used the transposon to mutagenize Pectobacterium versatile KD100, Pseudumonas coronafaciens PC27R and Escherichia coli 35150N. The fluorescence intensities of mutants expressing high GFP could be quantified and detected qualitatively. Transformation efficiency from conjugation ranged from 1600 to 1900 CFU per ml. We sequenced the upstream flanking regions, identified the putative truncated genes and demonstrated the restoration of the GFP phenotype through marker exchange. The mini-Tn5 transposon was also utilized to construct mutant a library of P. versatile for forward genetic screens.     

Uterine and placental 5-HT profile in different gestational period of albino rats

Possible role of 5-HT in pregnancy was investigated in albino rats by biological estimation of uterine and placental 5-HT contents in different periods of gestation in normal and drug treated rats. Uterine 5-HT level increased steadily from day-1 of gestation to reach the peak on day-7; thereafter, the level continued to decline throughout the period till day-20 when 5-HT level was lowest. From day-20, a mild secondary rise started and remained persistent even after parturition. The results show that a critical level of 5-HT in early gestational period is necessary for conception. Manipulation of endogenous 5-HT do not influence duration of gestation.     

Refined crystal structure of the phosphorylase-heptulose 2-phosphate-oligosaccharide-AMP complex

The crystal structure of phosphorylase b-heptulose 2-phosphate complex with oligosaccharide and AMP bound has been refined by molecular dynamics and crystallographic least-squares with the program XPLOR. Shifts in atomic positions of up to 4 A from the native enzyme structure were correctly determined by the program without manual intervention. The final crystallographic R value for data between 8 and 2.86 A resolution is 0.201, and the overall root-mean-square difference between the native and complexed structure is 0.58 A for all protein atoms. The results confirm the previous observation that there is a direct hydrogen bond between the phosphate of heptulose 2-phosphate and the pyridoxal phosphate 5'-phosphate group. The close proximity of the two phosphates is stabilized by an arginine residue, Arg569, which shifts from a site buried in the protein to a position where it can make contact with the product phosphate. There is a mutual interchange in position between the arginine and an acidic group, Asp283. These movements represent the first stage of the allosteric response which converts the catalytic site from a low to a high-affinity binding site. Communication of these changes to other sites is prevented in the crystal by the lattice forces, which also form the subunit interface. The constellation of groups in the phosphorylase transition state analogue complex provides a structural basis for understanding the catalytic mechanism in which the cofactor pyridoxal phosphate 5'-phosphate group functions as a general acid to promote attack by the substrate phosphate on the glycosidic bond when the reaction proceeds in the direction of glycogen degradation. In the direction of glycogen synthesis, stereoelectronic effects contribute to the cleavage of the C-1-O-1 bond. In both reactions the substrate phosphate plays a key role in transition state stabilization. The details of the oligosaccharide, maltoheptaose, interactions with the enzyme at the glycogen storage site are also described.     

Virulence and pathogenicity of a Candida albicans mutant with reduced filamentation

Deletion of DNA polymerase eta (Rad30/Polη) in pathogenic yeast Candida albicans is known to reduce filamentation induced by serum, ultraviolet, and cisplatin. Because nonfilamentous C. albicans is widely accepted as avirulent form, here we explored the virulence and pathogenicity of a rad30Δ strain of C. albicans in cell‐based and animal systems. Flow cytometry of cocultured fungal and differentiated macrophage cells revealed that comparatively higher percentage of macrophages was associated with the wild‐type than rad30Δ cells. In contrast, higher number of Polη‐deficient C. albicans adhered per macrophage membrane. Imaging flow cytometry showed that the wild‐type C. albicans developed hyphae after phagocytosis that caused necrotic death of macrophages to evade their clearance. Conversely, phagosomes kill the fungal cells as estimated by increased metacaspase activity in wild‐type C. albicans. Despite the morphological differences, both wild‐type and rad30? C. albicans were virulent with a varying degree of pathogenicity in mice models. Notably, mice with Th1 immunity were comparatively less susceptible to systemic fungal infection than Th2 type. Thus, our study clearly suggests that the modes of interaction of morphologically different C. albicans strains with the host immune cells are diverged, and host genetic background and several other attributing factors of the fungus could additionally determine their virulence.     

Energy Homeostasis and Obesity: The Therapeutic Role of Anorexigenic and Orexigenic Peptide

International Journal of Peptide Research and Therapeutics - The brain detects changes in energy depots and actuates metabolic and behavioral responses planned to hold energy balance. Hunger,...     

Red panda fine‐scale habitat selection along a Central Himalayan longitudinal gradient

Red panda Ailurus fulgens, an endangered habitat specialist, inhabits a narrow distribution range in bamboo abundance forests along mountain slopes in the Himalaya and Hengduan Mountains. However, their habitat use may be different in places with different longitudinal environmental gradients, climatic regimes, and microclimate. This study aimed to determine the habitat variables affecting red panda distribution across different longitudinal gradients through a multivariate analysis. We studied habitat selection patterns along the longitudinal gradient in Nepal's Himalaya which is grouped into the eastern, central, and western complexes. We collected data on red panda presence and habitat variables (e.g., tree richness, canopy cover, bamboo abundance, water availability, tree diameter, tree height) by surveys along transects throughout the species’ potential range. We used a multimodal inference approach with a generalized linear model to test the relative importance of environmental variables. Although the study showed that bamboo abundance had a major influence, habitat selection was different across longitudinal zones. Both canopy cover and species richness were unimportant in eastern Nepal, but their influence increased progressively toward the west. Conversely, tree height showed a decreasing influence on habitat selection from Eastern to Western Nepal. Red panda's habitat selection revealed in this study corresponds to the uneven distribution of vegetation assemblages and the dry climatic gradient along the eastern‐western Himalayas which could be related to a need to conserve energy and thermoregulate. This study has further highlighted the need of importance of bamboo conservation and site‐specific conservation planning to ensure long‐term red panda conservation.     

Impact of hyperglycemia on the expression of GLUT1 during oral carcinogenesis in rats

Molecular Biology Reports - On the background of the epidemiological link between diabetes and oral cancer, the present study aimed to analyze the potential involvement of selected glucose...