991 resultados para 197-1206


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Periodic estimation, monitoring and reporting on area under forest and plantation types and afforestation rates are critical to forest and biodiversity conservation, sustainable forest management and for meeting international commitments. This article is aimed at assessing the adequacy of the current monitoring and reporting approach adopted in India in the context of new challenges of conservation and reporting to international conventions and agencies. The analysis shows that the current mode of monitoring and reporting of forest area is inadequate to meet the national and international requirements. India could be potentially over-reporting the area under forests by including many non-forest tree categories such as commercial plantations of coconut, cashew, coffee and rubber, and fruit orchards. India may also be under-reporting deforestation by reporting only gross forest area at the state and national levels. There is a need for monitoring and reporting of forest cover, deforestation and afforestation rates according to categories such as (i) natural/primary forest, (ii) secondary/degraded forests, (iii) forest plantations, (iv) commercial plantations, (v) fruit orchards and (vi) scattered trees.

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Cryptococcus neoformans is a pathogenic basidiomycetous yeast responsible for more than 600,000 deaths each year. It occurs as two serotypes (A and D) representing two varieties (i.e. grubii and neoformans, respectively). Here, we sequenced the genome and performed an RNA-Seq-based analysis of the C. neoformans var. grubii transcriptome structure. We determined the chromosomal locations, analyzed the sequence/structural features of the centromeres, and identified origins of replication. The genome was annotated based on automated and manual curation. More than 40,000 introns populating more than 99% of the expressed genes were identified. Although most of these introns are located in the coding DNA sequences (CDS), over 2,000 introns in the untranslated regions (UTRs) were also identified. Poly(A)-containing reads were employed to locate the polyadenylation sites of more than 80% of the genes. Examination of the sequences around these sites revealed a new poly(A)-site-associated motif (AUGHAH). In addition, 1,197 miscRNAs were identified. These miscRNAs can be spliced and/or polyadenylated, but do not appear to have obvious coding capacities. Finally, this genome sequence enabled a comparative analysis of strain H99 variants obtained after laboratory passage. The spectrum of mutations identified provides insights into the genetics underlying the micro-evolution of a laboratory strain, and identifies mutations involved in stress responses, mating efficiency, and virulence.

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The HORMA domain (for Hop1p, Rev7p and MAD2) was discovered in three chromatin-associated proteins in the budding yeast Saccharomyces cerevisiae. This domain has also been found in proteins with similar functions in organisms including plants, animals and nematodes. The HORMA domain containing proteins are thought to function as adaptors for meiotic checkpoint protein signaling and in the regulation of meiotic recombination. Surprisingly, new work has disclosed completely unanticipated and diverse functions for the HORMA domain containing proteins. A. M. Villeneuve and colleagues (Schvarzstein et al., 2013) show that meiosis-specific HORMA domain containing proteins plays a vital role in preventing centriole disengagement during Caenorhabditis elegans spermatocyte meiosis. Another recent study reveals that S. cerevisiae Atg13 HORMA domain acts as a phosphorylation-dependent conformational switch in the cellular autophagic process. (C) 2014 Elsevier B.V. All rights reserved.

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Self-assembly of a chloro-bridged half-sandwich p-cymene ruthenium(II) complex Ru-2(mu-Cl-2)(eta(6)-p-cymene)(2)Cl-2] 1 with linear ditopic donor L; trans-1,2-bis(4-pyridyl) ethylene] in presence of 2 eq. AgNO3 in CH3CN yielded a chloro-bridged molecular rectangle 2. The rectangle 2 was isolated as nitrate salt in high yield (90 %) and characterized by infra-red, H-1 NMR spectroscopy including ESI-MS analyses. Molecular structure of 2 was determined by single crystal X-ray diffraction study The diffraction analysis shows that 2 adopts a tetranuclear rectangular geometry with the dimensions of 5.51 angstrom x 13.29 angstrom and forming an infinite supramolecular chain with large internal porosity arising through multiple pi-pi and CH-pi interactions between the adjacent rectangles. Furthermore, rectangle 2 is used as selective receptor for phenolic-nitroaromatic compounds such as picric acid, dinitrophenol and nitrophenol.

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Cryosorption pump is the only possible device to pump helium, hydrogen and its isotopes in fusion environment, such as high magnetic field and high plasma temperatures. Activated carbons are known to be the most suitable adsorbent in the development of cryosorption pumps. For this purpose, the data of adsorption characteristics of activated carbons in the temperature range 4.5 K to 77 K are needed, but are not available in the literature. For obtaining the above data, a commercial micro pore analyzer operating at 77 K has been integrated with a two stage GM cryocooler, which enables the cooling of the sample temperature down to 4.5 K. A heat switch mounted between the second stage cold head and the sample chamber helps to raise the sample chamber temperature to 77 K without affecting the performance of the cryocooler. The detailed description of this system is presented elsewhere. This paper presents the results of experimental studies of adsorption isotherms measured on different types of activated carbons in the form of granules, globules, flake knitted and non-woven types in the temperature range 4.5 K to 10 K using Helium gas as the adsorbate. The above results are analyzed to obtain the pore size distributions and surface areas of the activated carbons. The effect of adhesive used for bonding the activated carbons to the panels is also studied. These results will be useful to arrive at the right choice of activated carbon to be used for the development of cryosorption pumps.

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T-protein, an aminomethyltransferase, represents one of the four components of glycine cleavage system (GCS) and catalyzes the transfer of methylene group from H-protein intermediate to tetrahydrofolate (THF) forming N-5, N-10-methylene THF (CH2-THF) with the release of ammonia. The malaria parasite genome encodes T-, H- and L-proteins, but not P-protein which is a glycine decarboxylase generating the aminomethylene group. A putative GCS has been considered to be functional in the parasite mitochondrion despite the absence of a detectable P-protein homologue. In the present study, the mitochondrial localization of T-protein in the malaria parasite was confirmed by immunofluorescence and its essentiality in the entire parasite life cycle was studied by targeting the T-protein locus in Plasmodium berghei (Pb). PbT knock out parasites did not show any growth defect in asexual, sexual and liver stages indicating that the T-protein is dispensable for parasite survival in vertebrate and invertebrate hosts. The absence of P-protein homologue and the non-essentiality of T protein suggest the possible redundancy of GCS activity in the malaria parasite. Nevertheless, the H- and L-proteins of GCS could be essential for malaria parasite because of their involvement in alpha-lcetoacid dehydrogenase reactions. (C) 2014 Elsevier B.V. All rights reserved.

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Background: Serovars of Salmonella enterica, namely Typhi and Typhimurium, reportedly, are the bacterial pathogens causing systemic infections like gastroenteritis and typhoid fever. To elucidate the role and importance in such infection, the proteins of the Type III secretion system of Salmonella pathogenicity islands and two component signal transduction systems, have been mainly focused. However, the most indispensable of these virulent ones and their hierarchical role has not yet been studied extensively. Results: We have adopted a theoretical approach to build an interactome comprising the proteins from the Salmonella pathogeneicity islands (SPI) and two component signal transduction systems. This interactome was then analyzed by using network parameters like centrality and k-core measures. An initial step to capture the fingerprint of the core network resulted in a set of proteins which are involved in the process of invasion and colonization, thereby becoming more important in the process of infection. These proteins pertained to the Inv, Org, Prg, Sip, Spa, Ssa and Sse operons along with chaperone protein SicA. Amongst them, SicA was figured out to be the most indispensable protein from different network parametric analyses. Subsequently, the gene expression levels of all these theoretically identified important proteins were confirmed by microarray data analysis. Finally, we have proposed a hierarchy of the proteins involved in the total infection process. This theoretical approach is the first of its kind to figure out potential virulence determinants encoded by SPI for therapeutic targets for enteric infection. Conclusions: A set of responsible virulent proteins was identified and the expression level of their genes was validated by using independent, published microarray data. The result was a targeted set of proteins that could serve as sensitive predictors and form the foundation for a series of trials in the wet-lab setting. Understanding these regulatory and virulent proteins would provide insight into conditions which are encountered by this intracellular enteric pathogen during the course of infection. This would further contribute in identifying novel targets for antimicrobial agents. (C) 2014 Elsevier Ltd. All rights reserved.

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Background. Pediatric glioblastoma multiforme (GBM) is rare, and there is a single study, a seminal discovery showing association of histone H3.3 and isocitrate dehydrogenase (IDH) 1 mutation with a DNA methylation signature. The present study aims to validate these findings in an independent cohort of pediatric GBM, compare it with adult GBM, and evaluate the involvement of important functionally altered pathways. Methods. Genome-wide methylation profiling of 21 pediatric GBM cases was done and compared with adult GBM data (GSE22867). We performed gene mutation analysis of IDH1 and H3 histone family 3A (H3F3A), status evaluation of glioma cytosine-phosphate-guanine island methylator phenotype (G-CIMP), and Gene Ontology analysis. Experimental evaluation of reactive oxygen species (ROS) association was also done. Results. Distinct differences were noted between methylomes of pediatric and adult GBM. Pediatric GBM was characterized by 94 hypermethylated and 1206 hypomethylated cytosine-phosphate-guanine (CpG) islands, with 3 distinct clusters, having a trend to prognostic correlation. Interestingly, none of the pediatric GBM cases showed G-CIMP/IDH1 mutation. Gene Ontology analysis identified ROS association in pediatric GBM, which was experimentally validated. H3F3A mutants (36.4%; all K27M) harbored distinct methylomes and showed enrichment of processes related to neuronal development, differentiation, and cell-fate commitment. Conclusions. Our study confirms that pediatric GBM has a distinct methylome compared with that of adults. Presence of distinct clusters and an H3F3A mutation-specific methylome indicate existence of epigenetic subgroups within pediatric GBM. Absence of IDH1/G-CIMP status further indicates that findings in adult GBM cannot be simply extrapolated to pediatric GBM and that there is a strong need for identification of separate prognostic markers. A possible role of ROS in pediatric GBM pathogenesis is demonstrated for the first time and needs further evaluation.

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The bglA gene of Escherichia coli encodes phospho-beta-glucosidase A capable of hydrolyzing the plant-derived aromatic beta-glucoside arbutin. We report that the sequential accumulation of mutations in bglA can confer the ability to hydrolyze the related aromatic beta-glucosides esculin and salicin in two steps. In the first step, esculin hydrolysis is achieved through the acquisition of a four-nucleotide insertion within the promoter of the bglA gene, resulting in enhanced steady-state levels of the bglA transcript. In the second step, hydrolysis of salicin is achieved through the acquisition of a point mutation within the bglA structural gene close to the active site without the loss of the original catabolic activity against arbutin. These studies underscore the ability of microorganisms to evolve additional metabolic capabilities by mutational modification of preexisting genetic systems under selection pressure, thereby expanding their repertoire of utilizable substrates.

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In cells, N-10-formyltetrahydrofolate (N-10-fTHF) is required for formylation of eubacterial/organellar initiator tRNA and purine nucleotide biosynthesis. Biosynthesis of N-10-fTHF is catalyzed by 5,10-methylene-tetrahydrofolate dehydrogenase/cyclohydrolase (FolD) and/or 10-formyltetrahydrofolate synthetase (Fhs). All eubacteria possess FolD, but some possess both FolD and Fhs. However, the reasons for possessing Fhs in addition to FolD have remained unclear. We used Escherichia coli, which naturally lacks fhs, as our model. We show that in E. coli, the essential function of folD could be replaced by Clostridium perfringens fhs when it was provided on a medium-copy-number plasmid or integrated as a single-copy gene in the chromosome. The fhs-supported folD deletion (Delta folD) strains grow well in a complex medium. However, these strains require purines and glycine as supplements for growth in M9 minimal medium. The in vivo levels of N-10-fTHF in the Delta folD strain (supported by plasmid-borne fhs) were limiting despite the high capacity of the available Fhs to synthesize N-10-fTHF in vitro. Auxotrophy for purines could be alleviated by supplementing formate to the medium, and that for glycine was alleviated by engineering THF import into the cells. The Delta folD strain (harboring fhs on the chromosome) showed a high NADP(+)-to-NADPH ratio and hypersensitivity to trimethoprim. The presence of fhs in E. coli was disadvantageous for its aerobic growth. However, under hypoxia, E. coli strains harboring fhs outcompeted those lacking it. The computational analysis revealed a predominant natural occurrence of fhs in anaerobic and facultative anaerobic bacteria.

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The effects of two major electrodeposition process conditions, electrolyte bath temperature and current density, on the microstructure and crystallographic texture of pure tin coatings on brass and, ultimately, on the extent of whisker formation have been examined. The grain size of the deposited coatings increased with increasing electrolyte bath temperature and current density, which significantly affected the dominant texture: (211) or (420) was the dominant texture at low current densities whereas, depending on deposition temperature, (200) or (220) became the dominant texture at high current densities. After deposition, coatings were subjected to different environmental conditions, for example isothermal aging (room temperature, 50A degrees C, or 150A degrees C) for up to 90 days and thermal cycling between -25A degrees C and 85A degrees C for 100 cycles, and whisker growth was studied. The Sn coatings with low Miller index planes, for example (200) and (220), and with moderate aging temperature were more prone to whiskering than coating with high Miller index planes, for example (420), and high aging temperature. A processing route involving the optimum combination of current density and deposition temperature is proposed for suppressing whisker growth.

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Termites, herbivores and fire are recognized as major guilds that structure woody plant communities in African savanna and woodland ecosystems. An understanding of their interaction is crucial to design appropriate management regimes. The aim of this study was to evaluate the long-term impacts of herbivore, fire and termite activities on regeneration of trees. Permanent experimental quadrats were established in 1992 in the Sudanian woodland of Burkina Faso subjected to grazing by livestock and annual early fire and the control. Within the treatment quadrats, an inventory of the woody undergrowth community was conducted on termitaria occupied by Macrotermes subhyalinus, extended termitosphere (within 5 m radius from the mound base) and adjacent area (beyond 5 m from the mound base). Hierarchical analysis was performed to determine significant differences in species richness, abundance and diversity indices among vegetation patches within fire and herbivory treatments. Grazed quadrats had significantly (P < 0.001) more species and stem density of woody undergrowth than non-grazed quadrats but maintained similar level of species richness and stem density of woody undergrowth on termitaria. There were not significant differences (P>0.05) in species richness and stem density between burnt and unburnt quadrats. Termitaria supported a highly diverse woody undergrowth with higher stem density than either the extended termitosphere or rest of quadrats. The density of woody undergrowth was significantly related with mature trees of selected species on termitaria (R-2 = 0.593; P<0.001) than that on the extended termitosphere (R-2 = 0.333; P<0.001) and adjacent area (R-2 = 0.197; P<0.001). It can be concluded that termites facilitate the regeneration of woody species while grazing and annual early fire play a minor role in the regeneration of woody species. The current policy that prohibits grazing should be revised to accommodate the interests of livestock herders. (C) 2014 Elsevier GmbH. All rights reserved.

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This paper probes two research questions by ascertaining the factors which distinguish (i) innovative SMEs from those which are not, and (ii) SMEs which experienced a higher sales growth from those which experienced a lower sales growth, with reference to 197 engineering industry SMEs in Bangalore city. The differentiating factors between innovative and non-innovative SMEs brought out that SMEs must have ``own resources and capabilities'' in the form of internal strength and definite internal strategy if they have to innovate successfully. Younger and smaller firms which are ``entrepreneurial'' in nature and which are innovative contributed to higher sales growth of SMEs compared to older and larger firms which are ``salary-substitute firms'' in nature and which are not innovative. (C) 2015 Elsevier B.V. All rights reserved.

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In 1987, Kalai proved that stacked spheres of dimension d >= 3 are characterised by the fact that they attain equality in Barnette's celebrated Lower Bound Theorem. This result does not extend to dimension d = 2. In this article, we give a characterisation of stacked 2-spheres using what we call the separation index. Namely, we show that the separation index of a triangulated 2-sphere is maximal if and only if it is stacked. In addition, we prove that, amongst all n-vertex triangulated 2-spheres, the separation index is minimised by some n-vertex flag sphere for n >= 6. Furthermore, we apply this characterisation of stacked 2-spheres to settle the outstanding 3-dimensional case of the Lutz-Sulanke-Swartz conjecture that ``tight-neighbourly triangulated manifolds are tight''. For dimension d >= 4, the conjecture has already been proved by Effenberger following a result of Novik and Swartz. (C) 2015 Elsevier Inc. All rights reserved.