Changes in phosphatases and lipids following scrotal gamma irradiation in adult rat testis.

Effects of localized low (2.5 Gy) and high (10 Gy) levels of gamma irradiation on the testis of albino rats were studied. A marked increase in the testicular total lipid, phospholipid and cholesterol content was observed at all post-treatment intervals except at 16 weeks where the contents decreased. A significant decrease in the activity of acid phosphatase/g of testis was seen at both the doses, the minimum value being at 4 weeks. The decrease in acid phosphatase activity is correlated with the state of germ cell population in seminiferous tubule which is found to be depleted at 4 week interval. The alkaline phosphatase activity/g testis however, showed a significant increase, the maximum being at 4 weeks post-treatment. Thereafter, the values of the enzyme activity showed a slight recovery at 16 weeks post-irradiation. ATPase activity increased initially followed by a significant decrease at all post-treatment intervals.     

Analysis of codon usage in genes for nitrogen fixation from phylogenetically diverse diazotrophs

Summary A cluster analysis based on codon usage in genes for biological nitrogen fixation (nif genes) grouped diazotrophs into three distinct classes: anaerobes, cyanobacteria, and aerobes. In thenif genes ofKlebsiella pneumoniae there was no evidence for selection pressure in favor of highly translatable codons. However, in the nitrogen regulatory operonglnAntrBntrC of enteric bacteria the stoichiometrically high level of glutamine synthetase may be facilitated by the presence of efficiently translatable codons inglnA. Thenif genes of the cyanobacteriumAnabaena showed codon selection in favor of translational efficiency. Computation of codon adaptation indices for expression in heterologous systems indicated that the reading frames most suitable for expression ofnif genes inEscherichia coli, Bacillus subtilis, andSaccharomyces cerevisiae were present in azotobacters, clostridia, and cyanobacteria, respectively. In codon-usage-based cluster analysis, type 3 nitrogenase genes ofAzotobacter vinelandii grouped along with type 1 and type 2 genes. This is in contrast to the nucleotide sequence-based multiple alignment in which type 3 nitrogenase genes ofA. vinelandii have been reported to cluster with entirely unrelated diazotrophs such as methanogens and clostridia. This may be indicative of lateral transfer ofnif genes among widely divergent taxons. The chromosomal- and plasmid-locatednif genes of rhizobia also cluster separately in nucleotide sequence-based analysis but showed similar codon usage. These analyses suggested that the phylogeny ofnif genes drawn on the basis of nucleotide sequence homology was not masked by the taxon-specific pressure on codon usage.     

The use of biofertilizer of Calothrix sp. M103, enhanced by addition of iron and siderophore production

Calothrix sp. M103, enhanced by addition of iron and siderophore production was used as a biofertilizer. The strain was isolated from a colony on the surface root of a rice plant from a rice field in Bangladesh. It showed a marked and immediate increase in nitrogenase activity in response to the addition of iron and also a normal activity (compared with the control) under siderophore production. The addition of iron to iron-limited cultures resulted in a rapid increase in algal iron (11-fold) followed by a marked increase (9-fold) in nitrogenase activity, reaching about 11.8 kg N/ha/crop. This was more than twice the amount of nitrogen usually fixed by the alga during normal growth (controlled conditions), suggesting that pulsing algal inocula with iron would increase the efficiency of algae as a biofertilizer. Indeed, the use of an iron-pulsed inoculum of this strain as a biofertilizer resulted in an increase in the yield of sweetcorn by ca 143% over that produced by the control (no algal inoculation) and to ca a 73% increase over that produced by the normal inoculum (unpulsed with iron). The ability of this strain to produce siderophores has also led to both normal (compared with the control) nitrogenase activity as well as normal growth, which shows a marked contrast to other circumstances where the non-siderophore producing strains showed no growth at all. The significance of these observations on the enhancement of biofertilizer technology is discussed.     

A study on biological activity measurements and heterotrophic bacteria in a small freshwater lake

A 6-m-deep lake has been sampled to measure the temporal and depth-wise distribution of heterotrophic bacteria and biological activity in the water. Surface, mid-depth and bottom waters were analysed at monthly intervals for a period of one year. The coefficient of heterotrophic activity, alkaline phosphatase activity and biological oxygen demand are used as an index of biological activity. The bacterial community was at maximum during spring, coinciding with high values of biological activity. Highest biological activity was observed in the bottom waters. Dissolved organic carbon showed a significant positive correlation with most of the biological activity parameters. This suggests that biological activity, as measured by the coefficient of heterotrophic activity, was more closely related to the concentration of substrates than to population density of heterotrophic bacteria.     

3-methoxy-4,6-dihydroxymorphinandien-7-one,an alkaloid from Croton bonplandianum

A new alkaloid, 3-methoxy-4,6-dihydroxymorphinandien-7-one, and norsinoacutine have been isolated from extracts of Croton bonplandianum.     

Developmental mutants of Anabaena doliolum defective in repair of UV-damage

Summary Nitrosoguanidine induced blue pigment mutants of the blue-green alga Anabaena doliolum were isolated. The blue-mutants on further characterization were grouped into three developmental phenotypes — (i) those forming doli-form blue-spores of heterogenous size i.e., Ad 011, (ii) those forming spheroidal cells in the stationary phase, some of which behave like spores on transfer to fresh medium i.e., Ad 012, and (iii) those showing no sporulation and conditionally producing abnormal cells in the presence of combined nitrogen only i.e., Ad 007. The former two classes of mutants showed the formation of abnormal cells irrespective of the presence or absence of combined nitrogen sources in the medium. The formation of abnormal cells in the filaments of the above mutants were distinguished by their larger size and irregular mode of division leading to true-branch formation. The comparative characterization of these mutant strains with the parental one showed sluggish growth, increased UV-sensitivity, almost unchanged photorepair capacity, a marked change in the pigment composition and relative resistance to nitrosoguanidine. Irregular cell division in both space and time in the mutant strains and their increased sensitivity to ultraviolet irradiation indicate the possible involvement of dark repair system in maintaining the precision of cell cycle in this alga.     

Synthesis and degradation of proteins during wheat endosperm development

Synthesis of proteins rich in lysine declines progressively with endosperm development and these proteins appear to be degraded preferentially at later stages. The proteolytic enzymes in extracts of endosperms at a late stage of development release considerably more lysine radioactivity from labelled endosperm proteins as compared with the enzymes in endosperms at an early stage.     

Immune Response to Dengue Virus Infection in Pediatric Patients in New Delhi,India—Association of Viremia,Inflammatory Mediators and Monocytes with Disease Severity

Dengue virus, a mosquito-borne flavivirus, is a causative agent for dengue infection, which manifests with symptoms ranging from mild fever to fatal dengue shock syndrome. The presence of four serotypes, against which immune cross-protection is short-lived and serotype cross-reactive antibodies that might enhance infection, pose a challenge to further investigate the role of virus and immune response in pathogenesis. We evaluated the viral and immunological factors that correlate with severe dengue disease in a cohort of pediatric dengue patients in New Delhi. Severe dengue disease was observed in both primary and secondary infections. Viral load had no association with disease severity but high viral load correlated with prolonged thrombocytopenia and delayed recovery. Severe dengue cases had low Th1 cytokines and a concurrent increase in the inflammatory mediators such as IL-6, IL-8 and IL-10. A transient increase in CD14⁺CD16⁺ intermediate monocytes was observed early in infection. Sorting of monocytes from dengue patient peripheral blood mononuclear cells revealed that it is the CD14+ cells, but not the CD16+ or the T or B cells, that were infected with dengue virus and were major producers of IL-10. Using the Boruta algorithm, reduced interferon-α levels and enhanced aforementioned pro-inflammatory cytokines were identified as some of the distinctive markers of severe dengue. Furthermore, the reduction in the levels of IL-8 and IL-10 were identified as the most significant markers of recovery from severe disease. Our results provide further insights into the immune response of children to primary and secondary dengue infection and help us to understand the complex interplay between the intrinsic factors in dengue pathogenesis.     

Detection and identification of phytoplasma associated with witches’ broom and little leaf disease in Arundo donax: first report from India

During the survey of two successive years 2012–2013, in nearby places of Gorakhpur districts, Uttar Pradesh, India, Arundo donax plants were found to be exhibiting witches’ broom, excessive branching accompanied with little leaf symptoms with considerable disease incidence. Nested PCR carried out with universal primers pair R16F2n/R16R2 employing the PCR (P1/P7) product as a template DNA (1:20) resulted in expected size positive amplification ~1.2 kb in all symptom-bearing plants suggested the association of phytoplasma with witches’ broom disease of Narkat plants. BLASTn analysis of the 16S rRNA gene sequence showed the highest (99%) sequence identity with Candidatus phytoplasma asteris (16SrI group). In phylogenetic analysis, the sequence data showed close relationships with the members of 16SrI phytoplasma and clustered within a single clade of 16SrI group and closed to B subgroup representatives. This is a first report of 16Sr I-B group phytoplasma associated with witches’ broom accompanied with little leaf disease of Narkat in India.