Radioprotective mechanism of Podophyllum hexandrum during spermatogenesis

RP-1, a herbal preparation of Podophyllum hexandrum has already been reported to provide protection against whole body lethal gamma irradiation (10 Gy). It has also been reported to render radioprotection to germ cells during spermatogenesis. Present study was undertaken to unravel the cellular and molecular mechanism of action of RP-1 on testicular system in strain 'A' mice. Various antioxidant parameters such as thiol content, glutathione peroxidase (GPx), glutathione reductase (GR), glutathione-S-transferase (GST) enzyme activity, lipid peroxidation (LPO) and total protein levels were investigated. Thiol content was seen to increase significantly (p < 0.05) in both RP-1 alone and RP-1 pretreated irradiated groups over the irradiated groups at 8, 16 and 24 h. Irradiation (10 Gy) significantly decreased GPx, GST and GR activity in comparison to untreated control but RP-1 treatment before irradiation significantly (p < 0.05) countered radiation-induced decrease in the activity of these enzymes. Radiation-induced LPO was also found to be reduced at all time intervals by RP-1 treatment before irradiation. As compared to irradiated group the protein content in testicular tissue was increased in RP-1 pretreated irradiated group at 4 and 16 h significantly (p < 0.05). Comets revealed by single-cell gel electrophoresis were significantly longer (p < 0.001) in irradiated mice than in unirradiated control. RP-1 treatment before irradiation, however, rendered significant increase (p < 0.05) in comet length over the corresponding control and irradiated group initially at 4 h but at later time points, this was reduced significantly (p < 0.01) as compared to the irradiated group. RP-1 treatment alone rendered shorter comets at 8, 16 and 24 h than irradiated groups (p < 0.001). This study implies that RP-1 offers radioprotection at biochemical and cytogenetic level by protecting antioxidant enzymes, reducing LPO and increasing thiol content.     

Evolutionary constraints associated with functional specificity of the CMGC protein kinases MAPK, CDK, GSK, SRPK, DYRK, and CK2alpha

Amino acid residues associated with functional specificity of cyclin-dependent kinases (CDKs), mitogen-activated protein kinases (MAPKs), glycogen synthase kinases (GSKs), and CDK-like kinases (CLKs), which are collectively termed the CMGC group, were identified by categorizing and quantifying the selective constraints acting upon these proteins during evolution. Many constraints specific to CMGC kinases correspond to residues between the N-terminal end of the activation segment and a CMGC-conserved insert segment associated with coprotein binding. The strongest such constraint is imposed on a "CMGC-arginine" near the substrate phosphorylation site with a side chain that plays a role both in substrate recognition and in kinase activation. Two nearby buried waters, which are also present in non-CMGC kinases, typically position the main chain of this arginine relative to the catalytic loop. These and other CMGC-specific features suggest a structural linkage between coprotein binding, substrate recognition, and kinase activation. Constraints specific to individual subfamilies point to mechanisms for CMGC kinase specialization. Within casein kinase 2alpha (CK2alpha), for example, the binding of one of the buried waters appears prohibited by the side chain of a leucine that is highly conserved within CK2alpha and that, along with substitution of lysine for the CMGC-arginine, may contribute to the broad substrate specificity of CK2alpha by relaxing characteristically conserved, precise interactions near the active site. This leucine is replaced by a conserved isoleucine or valine in other CMGC kinases, thereby illustrating the potential functional significance of subtle amino acid substitutions. Analysis of other CMGC kinases similarly suggests candidate family-specific residues for experimental follow-up.     

Diagnostic pitfalls in fine needle aspiration cytology of pleomorphic lipoma. A case report

BACKGROUND: Pleomorphic lipoma is an unusual pseudosarcomatous condition with characteristic morphology. Despite its pleomorphic appearance, it follows a benign course and does not recur or metastasize if completely excised. CASE: A 66-year-old man presented with swelling in the back of the neck of approximately six months' duration. The focally cellular aspirate revealed round to oval, hyperchromatic cells, rare multinucleated cells and fragments of mature adipose tissue. On initial evaluation, the smear pattern suggested a malignant neoplasm. However, upon review of the cytologic material along with histology, the characteristic pattern, including floret cells, was recognized. CONCLUSION: The rarity of pleomorphic lipoma and the atypical cellular features of the aspirate can cause difficulty in diagnosing this entity. Awareness of this rare but not-uncommon entity, along with clinical correlation, is crucial in arriving at the correct diagnosis.     

FGF receptor mutations: dimerization syndromes, cell growth suppression, and animal models

This review describes recent progress in the field of fibroblast growth factor receptors (FGFRs) with an emphasis on the role of FGFR mutants in skeletal malformations. This family of four receptors contains the most frequent germline mutations in humans. More than 75 mutations have been recorded, which account for more than seven skeletal syndromes. The common cause for all the mutant phenotypes is gain-of-function by receptor activation through three major mechanisms: receptor dimerization, kinase activation, and increased affinity for FGF. The severity of the disease is correlated with both the extent of receptor activation and the specific tissue in which the mutant receptor form is expressed. Paradoxically, the consequence of receptor activation is inhibition of chondrocyte cell growth through signaling pathways that are cell-type specific. The structure of the FGFR-FGF complex and its possible ternary complex with heparin explain the mechanism of receptor dimerization in the ectodomain and the possible contribution by some of the mutations to this process. Analysis of FGFR3 mutant mice produced by gene targeting as models for human disease, and studies in cell lines, have begun to delineate the novel signaling pathways of FGFR3 and to define possible targets for therapy.     

Lake regionalization and diatom metacommunity structuring in tropical South America

Lakes and their topological distribution across Earth's surface impose ecological and evolutionary constraints on aquatic metacommunities. In this study, we group similar lake ecosystems as metacommunity units influencing diatom community structure. We assembled a database of 195 lakes from the tropical Andes and adjacent lowlands (8°N–30°S and 58–79°W) with associated environmental predictors to examine diatom metacommunity patterns at two different levels: taxon and functional (deconstructed species matrix by ecological guilds). We also derived spatial variables that inherently assessed the relative role of dispersal. Using complementary multivariate statistical techniques (principal component analysis, cluster analysis, nonmetric multidimensional scaling, Procrustes, variance partitioning), we examined diatom–environment relationships among different lake habitats (sediment surface, periphyton, and plankton) and partitioned community variation to evaluate the influence of niche‐ and dispersal‐based assembly processes in diatom metacommunity structure across lake clusters. The results showed a significant association between geographic clusters of lakes based on gradients of climate and landscape configuration and diatom assemblages. Six lake clusters distributed along a latitudinal gradient were identified as functional metacommunity units for diatom communities. Variance partitioning revealed that dispersal mechanisms were a major contributor to diatom metacommunity structure, but in a highly context‐dependent fashion across lake clusters. In the Andean Altiplano and adjacent lowlands of Bolivia, diatom metacommunities are niche assembled but constrained by either dispersal limitation or mass effects, resulting from area, environmental heterogeneity, and ecological guild relationships. Topographic heterogeneity played an important role in structuring planktic diatom metacommunities. We emphasize the value of a guild‐based metacommunity model linked to dispersal for elucidating mechanisms underlying latitudinal gradients in distribution. Our findings reveal the importance of shifts in ecological drivers across climatic and physiographically distinct lake clusters, providing a basis for comparison of broad‐scale community gradients in lake‐rich regions elsewhere. This may help guide future research to explore evolutionary constraints on the rich Neotropical benthic diatom species pool.     

Characterisation of pathogenic and molecular diversity in Sclerospora graminicola,the causal agent of pearl millet downy mildew

Genotypic diversity among 46 isolates of Sclerospora graminicola collected from seven states in India during 1992–2005 was determined through pathotyping and AFLP analysis. A high level of variation was observed among the isolates for downy mildew incidence, latent period and virulence index. Based on the reaction on a set of nine pearl millet lines, 46 isolates were classified in 21 pathotypes. Quantitative differences in virulence levels of the test isolates were assessed by calculating the virulence index (disease incidence × latent period ^? 1). A dendrogram generated by the average linkage cluster analysis of virulence index clustered the 46 isolates into eight groups. Region-specific grouping of five isolates from Gujarat and six from Rajasthan was observed within two distinct groups. Temporal variation was also observed among the isolates collected from the same location and same host over the years. A total of 297 bands were scored following selective amplification with three primer combinations E-TT/M-CAG, E-AT/M-CAG and E-TG/M-CAT and all of them were polymorphic. Cluster analysis of AFLP data clustered the test isolates into seven groups. Analysis of molecular variance indicated that variation in the S. graminicola populations was largely due to differences among the isolates within the states.     

Phosphatidylethanolamine from Phosphatidylserine Decarboxylase2 is Essential for Autophagy Under Cadmium Stress in Saccharomyces cerevisiae

Cadmium (Cd) is a potent toxic element used in several industries and in the process contaminates air, soil, and water. Exposure of Saccharomyces cerevisiae to Cd increases the major phospholipids, and profound increase was observed in phosphatidylethanolamine (PE). In yeast, there are four different pathways contributing to the biosynthesis of PE, and contribution to PE pool through phosphatidylserine decarboxylase2 (psd2) is not significant in normal conditions. Upon Cd exposure, psd2Δ strain showed a significant decrease in major phospholipids including PE. When exposed to Cd, wild-type (WT) cells depicted an increase in ER stress and autophagy, whereas in psd2, ER stress was noted but autophagy process was impaired. The supplementation of ethanolamine did not overcome the Cd stress and also the autophagy process, whereas overexpression of PSD2 in psd2Δ increased the cellular tolerance, PE levels, and the autophagy process against Cd stress. From our studies, we can suggest that PSD2 of S. cerevisiae has an important role in PE synthesis and in autophagy process under Cd stress.     

Evaluation of recombinant outer membrane protein based vaccine against Salmonella Typhimurium in birds

Food-borne diseases caused by Salmonella enterica from poultry sources represent an important public health problem and no reliable control by vaccination has proved effective despite research. The aim of the present study was to evaluate the use of recombinant OmpC protein for immunization of birds to elucidate its protection against virulent Salmonella Typhimurium. The recombinant OmpC protein was prepared after cloning and expressing ompC gene and was characterized by SDS-PAGE and Western blot analyses. The protein preparations were tested as vaccine candidate in layer birds by comparing the immune response, protection and organ clearance against crude lysate and control. The biologically functional recombinant 43 kDa truncated OmpC protein proved to be a good immunogen which induced a significantly high humoral immune response than control. At the same time, it primed a stable cell-mediated immune response. A protective index (based on faecal shedding of organism) of rOmpC based preparations ranged between 50 and 75% as observed for 3 weeks after challenge. Therefore, the protein preparations conferred satisfactory protection against challenge infections with virulent strains of S. Typhimurium as evidenced by limited faecal shedding and minimal detection of Salmonella from edible tissues and eggs. These findings suggest the possibility to explore the use of S. enterica OMP protein for the production of novel vaccine.