Performance and persistence of phosphate solubilizingAzotobacter chroococcum in wheat rhizosphere

Survival and establishment of inoculant strains ofAzotobacter chroococcum NV 11 and its mutant NV 43 were assessed in sterilized soil and rhizosphere soil of wheat plants at 7 and 15 d interval, respectively, after sowing,i.e., up to 45 d under pot-house conditions. There was an apparent decrease in population of both strains in bulk soil but a steady increase was observed in root zones of the wheat plant. 10³ to 10⁴ introduced bacteria per g root were found sticking to roots. Further studies indicated that inoculant strains ofAzotobacter could survive, proliferate and establish well in root zones.     

Human immunodeficiency virus-1-tat induces matrix metalloproteinase-9 in monocytes through protein tyrosine phosphatase-mediated activation of nuclear transcription factor NF-kappaB

An appreciable increase in G(M3) with a concomitant decrease in some neolacto-series gangliosides was observed during differentiation of human colonic carcinoma HCT 116 cells induced by a differentiating agent. When the cells were treated with brefeldin A (BFA), a striking increase in de novo biosynthesis of G(M3) and a decrease in biosynthesis of neolactoseries gangliosides were observed after 6 h. Clear morphological changes to differentiated epithelial cells and an arrest of cells in the G0/G1 phase of the cell cycle were observed after 1 day of treatment. Then the cells were led to apoptosis. This activity was not affected by forskolin, which antagonizes the effects of BFA on protein transport and the Golgi apparatus. These results suggest that the differentiation-inducing activity of BFA might be due to its modulatory effect on ganglioside biosynthesis, and that a specific change in ganglioside pattern is an essential prerequisite for induction of differentiation, providing a novel target for differentiation therapy of cancer.     

Boundary element-associated factor 32B connects chromatin domains to the nuclear matrix

Chromatin domain boundary elements demarcate independently regulated domains of eukaryotic genomes. While a few such boundary sequences have been studied in detail, only a small number of proteins that interact with them have been identified. One such protein is the boundary element-associated factor (BEAF), which binds to the scs' boundary element of Drosophila melanogaster. It is not clear, however, how boundary elements function. In this report we show that BEAF is associated with the nuclear matrix and map the domain required for matrix association to the middle region of the protein. This region contains a predicted coiled-coil domain with several potential sites for posttranslational modification. We demonstrate that the DNA sequences that bind to BEAF in vivo are also associated with the nuclear matrix and colocalize with BEAF. These results suggest that boundary elements may function by tethering chromatin to nuclear architectural components and thereby provide a structural basis for compartmentalization of the genome into functionally independent domains.     

A new frog species from the central western Ghats of India, and its phylogenetic position

Tropical evergreen forests of Indian subcontinent, especially of the Western Ghats, are known hot spots of amphibian diversity, where many new anuran species await to be identified. Here we describe from the Sharavathi River basin of central Western Ghats a new shrub-frog taxon related to the anuran family Rhacophoridae. The new frog possesses the characteristic features of rhacophorids (dilated digit tips with differentiated pads circumscribed by a complete groove, intercalary cartilages on digits, T-shaped terminal phalanges and granular belly, the adaptive characters for arboreal life forms), but also a suite of unique features that distinguish it from all known congeners in the region. Morphogenetic analysis based on morphological characteristics and diversity in the mitochondrial 12S and 16S rRNA genes revealed it to be a new Philautus species that we named Philautus neelanethrus sp. nov. The phylogenetic analysis suggests the new frog to represent a relatively early Philautus species lineage recorded from the region. The distribution pattern of the species suggests its importance as a bioindicator of habitat health. In general, this relatively widespread species was found distributed only in non-overlapping small stretches, which indirectly indicates the fragmentation of the evergreen to moist deciduous forests that characterize the Western Ghats. Thus the discovery of the new rhacophorid species described here not only further reinforces the significance of the Western Ghats as a major hotspot of amphibian biodiversity, but also brings into focus the deterioration of forest habitats in the region and the need for prioritization of their conservation.     

Topology of Type II REases revisited; structural classes and the common conserved core

Type II restriction endonucleases (REases) are deoxyribonucleases that cleave DNA sequences with remarkable specificity. Type II REases are highly divergent in sequence as well as in topology, i.e. the connectivity of secondary structure elements. A widely held assumption is that a structural core of five beta-strands flanked by two alpha-helices is common to these enzymes. We introduce a systematic procedure to enumerate secondary structure elements in an unambiguous and reproducible way, and use it to analyze the currently available X-ray structures of Type II REases. Based on this analysis, we propose an alternative definition of the core, which we term the alphabetaalpha-core. The alphabetaalpha-core includes the most frequently observed secondary structure elements and is not a sandwich, as it consists of a five-strand beta-sheet and two alpha-helices on the same face of the beta-sheet. We use the alphabetaalpha-core connectivity as a basis for grouping the Type II REases into distinct structural classes. In these new structural classes, the connectivity correlates with the angles between the secondary structure elements and with the cleavage patterns of the REases. We show that there exists a substructure of the alphabetaalpha-core, namely a common conserved core, ccc, defined here as one alpha-helix and four beta-strands common to all Type II REase of known structure.     

Dystonin/Bpag1--a link to what?

The dystonin/Bpag1 cytoskeletal interacting proteins play important roles in maintaining cytoarchitecture integrity in skin and in the neuromuscular system. The most profound phenotype observed in the dystonin mutant dystonia musculorum (dt) mice is a severe movement disorder, attributed in large part to sensory neuron degeneration. The molecular basis for this phenotype is currently not clear, despite several studies indicating possible causes for the pathology in dt mice. Complicating the picture of what essential dystonin functions are lost in dt mice is the fact that our understanding of the very nature of what dystonin is has evolved greatly over the past decade. Elucidating the roles of dystonin most relevant to neuronal function and survival should help to shed light on some of the common mechanisms underlying neurodegeneration.     

L-carnitine increases liver alpha-tocopherol and lowers liver and plasma triglycerides in aging ovariectomized rats

The objective of this study was to determine whether dietary L-carnitine can influence the status of alpha-tocopherol, retinol and selected lipid parameters in aging ovariectomized rats, an animal model for the menopausal state. Fourteen Fisher-344 female rats 18 months old were acclimated for 4 weeks and ovarectomized. Seven rats per treatment were assigned to either a control group fed ad libitum AIN-93M diet or a carnitine group fed the same diet supplemented with L-carnitine. After an 8-week feeding period, blood and selected tissues were taken for analyses. No differences were noted in food intake, body weight, or organ weights due to L-carnitine. Dietary carnitine significantly increased liver alpha-tocopherol and tended to increase plasma alpha-tocopherol (P<.09). No changes in alpha-tocopherol were observed in other tissues including the brain, lungs and retroperitoneal fat. Retinol levels in plasma and tissues were not affected by supplemental L-carnitine. Significant decreases in liver and plasma triglyceride (TG) levels were noted, suggesting increased utilization of fatty acids. No differences were observed in the fatty acid profile of tissues. The results provide evidence that dietary supplementation of L-carnitine enhances the alpha-tocopherol status and improves the utilization of fat leading to lowering of the liver and plasma levels of TG in aging ovariectomized rats. Whether supplemental L-carnitine may be of benefit to postmenopausal women in lowering plasma TG and improving the antioxidant status remains to be studied.     

Rudra interrupts receptor signaling complexes to negatively regulate the IMD pathway

Insects rely primarily on innate immune responses to fight pathogens. In Drosophila, antimicrobial peptides are key contributors to host defense. Antimicrobial peptide gene expression is regulated by the IMD and Toll pathways. Bacterial peptidoglycans trigger these pathways, through recognition by peptidoglycan recognition proteins (PGRPs). DAP-type peptidoglycan triggers the IMD pathway via PGRP-LC and PGRP-LE, while lysine-type peptidoglycan is an agonist for the Toll pathway through PGRP-SA and PGRP-SD. Recent work has shown that the intensity and duration of the immune responses initiating with these receptors is tightly regulated at multiple levels, by a series of negative regulators. Through two-hybrid screening with PGRP-LC, we identified Rudra, a new regulator of the IMD pathway, and demonstrate that it is a critical feedback inhibitor of peptidoglycan receptor signaling. Following stimulation of the IMD pathway, rudra expression was rapidly induced. In cells, RNAi targeting of rudra caused a marked up-regulation of antimicrobial peptide gene expression. rudra mutant flies also hyper-activated antimicrobial peptide genes and were more resistant to infection with the insect pathogen Erwinia carotovora carotovora. Molecularly, Rudra was found to bind and interfere with both PGRP-LC and PGRP-LE, disrupting their signaling complex. These results show that Rudra is a critical component in a negative feedback loop, whereby immune-induced gene expression rapidly produces a potent inhibitor that binds and inhibits pattern recognition receptors.