1-Halo analogs of dihydroxyacetone 3-phosphate. The effects of the fluoro analog on cytosolic glycerol-3-phosphate dehydrogenase and triosephosphate isomerase.

Fluoro-o-hydorxyacetone phosphate (fluoroacetol phosphate) has been prepared by oxidation of 1-fluoro-3-chloro-2-propanol to 1-fluoro-3-chloroacetone, phosphorylation with silver dibenzylphosphate, and the intermediate isolation of 1-fluoro-3-hydroxyacetone phosphate dibenzyl ester, followed by catalytic hydrogenation and preparation of the stable monosodium salt. The chloro analog as the pure, stable monosodium salt has been prepared by a similar route from 1,3-dichloroacetone. 1-Fluoro-3-hydroxyacetone-P is substrate for cytosolic NAD+-linked glycerol-3-P dehydrogenese (EC 1.1.1.8) from rabbit skeletal muscle with an apparent Km of 50 mM under conditions in which dihydroxyacetone-P exhibits an apparent Km of 0.15 mM. Under these conditions the fluoro analog is 85% hydrated wheras dihydroxyacetone-P has been shown by others to be 44% hydrated. The turnover numbers are 49,000 molecules of NADH oxidized per minute per molecule of enzyme at 25 degrees with the fluoro analog as substrate, and 60,000 with dihydrocyacetone-P as substrate. The product of the reduction of the fluoro analog has been identified as 1-fluorodeoxyglycerol-3-P. 1-Fluoro-3-hydroxyacetone-P is comparatively weak irreversible inhibitor at 4 degrees of rabbit muscle triosephosphate isomerase (EC 5.3.1.1) with second-order rate constant of 2.6 M minus 1 sec minus 1. Inhibition by pyrazole in vivo of alcohol dehydrogenese catalyzed oxidation of 1-fluorodeoxyglecerol-3-P indicates in mice the reduction of 1-fluoro-3-hydroxyacetone-P to -l-1-fluorodexoxyglycerol-3-P is not significant metabolic route, or that an alternative route exists when the alcohol dehydrogenase dependent pathway is inhibited.     

Pediatric glioblastoma cells inhibit neurogenesis and promote astrogenesis,phenotypic transformation and migration of human neural progenitor cells within cocultures

Neural progenitor cell (NPC) fate is influenced by a variety of biological cues elicited from the surrounding microenvironment and recent studies suggest their possible role in pediatric glioblastoma multiforme (GBM) development. Since a few GBM cells also display NPC characteristics, it is not clear whether NPCs transform to tumor cell phenotype leading to the onset of GBM formation, or NPCs migrate to developing tumor sites in response to paracrine signaling from GBM cells. Elucidating the paracrine interactions between GBM cells and NPCs in vivo is challenging due to the inherent complexity of the CNS. Here, we investigated the interactions between human NPCs (ReNcell) and human pediatric GBM-derived cells (SJ-GBM2) using a Transwell^® coculture setup to assess the effects of GBM cells on ReNcells (cytokine and chemokine release, viability, phenotype, differentiation, migration). Standalone ReNcell or GBM cultures served as controls. Qualitative and quantitative results from ELISA^®, Live/Dead^® and BrdU assays, immunofluorescence labeling, western blot analysis, and scratch test suggests that although ReNcell viability remained unaffected in the presence of pediatric GBM cells, their morphology, phenotype, differentiation patterns, neurite outgrowth, migration patterns (average speed, distance, number of cells) and GSK-3β expression were significantly influenced. The cumulative distance migrated by the cells in each condition was fit to Furth's formula, derived formally from Ornstein-Uhlenbeck process. ReNcell differentiation into neural lineage was compromised and astrogenesis promoted within cocultures. Such coculture platform could be extended to identify the specific molecules contributing to the observed phenomena, to investigate whether NPCs could be transplanted to replace lesions of excised tumor sites, and to elucidate the underlying molecular pathways involved in GBM-NPC interactions within the tumor microenvironment.     

Screening of plant growth promotion ability among bacteria isolated from field-grown sorghum under different managements in Brazilian drylands

Sorghum [Sorghum bicolor (L.) Moench] is a multipurpose grass cultivated in drylands due to its adaptation to drought. However the characteristics of sorghum-associated bacteria are not known in the Brazilian drylands. The aim of this study was to isolate and evaluate the plant growth promotion potential bacteria from field-grown sorghum under two irrigation and manure application levels in a Brazilian semi-arid reagion. Sorghum was irrigated with 3 or 1 mm day^?1 and fertilized or not with liquid goat manure. Bacteria were obtained from surface-disinfected roots applying two nitrogen-free semi-solid media. The bacteria were evaluated for the presence of nifH gene, 16S rRNA sequences, calcium-phosphate solubilization, production of auxins and siderophores and for sorghum growth promotion. We obtained 20 out of 24 positive bacteria for nifH. The isolates were classified as in six different genera. All isolates produced auxins “in vitro”, six bacteria produced siderophores and three Enterobacteriaceae solubilized calcium-phosphate. At least ten bacteria resulted in the increased total N content in the sorghum shoots, comparable to fertilization with 50 mg N plant^?1 week^?1 and to inoculation with Azospirillum brasilense Ab-V5. Enterobacter sp. ESA 57 was the best sorghum plant-growth promoting bacteria isolated in this study.     

Characterisation of wheat germplasm for slow rust resistance against Puccinia striiformis

Thirty-seven wheat germplasm were screened under artificial epiphytotic conditions against stripe rust of wheat at University Research Farm, Chatha, during Rabi, 2013–2014 and 2014–2015. On the basis of final rust severity (FRS), AURPC (Area Under Rust Progress Curve) and CI (Coefficient of Infection), 8 genotypes ((DWR 16, HD2281, VL616, K65, UP2121, HD2329, HD2307 and Lal Bahadur) exhibited partial resistance against the disease. PCR profiles revealed co-dominant pattern with distinct fragment of 150 bp in 14 germplasm, showing the presence of Yr18 gene and 229 bp band in 16 germplasm exhibited absence of Yr18.     

Genetic Mapping in Escherichia coli K-12 by Radiation-Induced Crossing-Over

Conventional methods for chromosomal mapping in Escherichia coli are (i) interruption of matings to obtain minimum marker entry times, (ii) linkage analysis of recombinants, and (iii) cotransduction. Method (i) has a resolution of about 0.5 min (5 x 10(4) nucleotides) and is not useful for distances less than about 1 min; methods (ii) and (iii) are capable of better resolution but are generally not very reproducible and no general theory is available for translating crossing-over and cotransduction frequencies into physical chromosomal distances. We found that when merozygotes are irradiated (X rays or ultraviolet light) soon after marker transfer, high linkage values (0.8 to 1.0) between nearby marker pairs decrease with radiation dose to 0.5. Our results are quantitatively consistent with the idea that radiations induce crossing-over lesions proportional to dose, and the number of such lesions between two markers is proportional to the physical separation of the markers in the range that can also be measured by interruption of mating (0.5 to 4.0 min). Additivity relations among markers are also satisfied. We used this technique to measure the distances (0.1 to 1.0 min) between several pairs of closely linked markers.     

Unraveling the efficiency of RAPD and SSR markers in diversity analysis and population structure estimation in common bean

Increase in food production viz-a-viz quality of food is important to feed the growing human population to attain food as well as nutritional security. The availability of diverse germplasm of any crop is an important genetic resource to mine the genes that may assist in attaining food as well as nutritional security. Here we used 15 RAPD and 23 SSR markers to elucidate diversity among 51 common bean genotypes mostly landraces collected from the Himalayan region of Jammu and Kashmir, India. We observed that both the markers are highly polymorphic. The discriminatory power of these markers was determined using various parameters like; percent polymorphism, PIC, resolving power and marker index. 15 RAPDs produced 171 polymorphic bands, while 23 SSRs produced 268 polymorphic bands. SSRs showed a higher PIC value (0.300) compared to RAPDs (0.243). Further the resolving power of SSRs was 5.241 compared to 3.86 for RAPDs. However, RAPDs showed a higher marker index (2.69) compared to SSRs (1.279) that may be attributed to their higher multiplex ratio. The dendrograms generated with hierarchical UPGMA cluster analysis grouped genotypes into two main clusters with various degrees of sub clustering within the cluster. Here we observed that both the marker systems showed comparable accuracy in grouping genotypes of common bean according to their area of cultivation. The model based STRUCTURE analysis using 15 RAPD and 23 SSR markers identified a population with 3 sub-populations which corresponds to distance based groupings. High level of genetic diversity was observed within the population. These findings have further implications in common bean breeding as well as conservation programs.