Inheritance of downy mildew resistance, β-1,3-glucanases and peroxidases in pearl millet [Pennisetum glaucum (L.) R. Br.] crosses

The inheritance of resistance to downy mildew disease and the defense-related enzymes β-1,3-glucanase and peroxidase was studied in crosses of pearl millet using a generation-mean analysis. The study material comprised six generations (susceptible and resistant parents, F₁, F₂, BC₁ and BC₂) in three crosses. Seedlings from these generations were inoculated with the downy mildew pathogen Sclerospora graminicola and disease incidence was recorded. Analysis of constitutive levels of β-1,3-glucanase and peroxidase in the seedlings of different generations indicated that the resistant populations showed higher enzyme activities, while lower activities of the enzymes were recorded in the susceptible populations. In the generation-mean analysis, the significance of scaling tests revealed the existence of non-allelic interactions in the inheritance of resistance to downy mildew as well as with the enzymes. Among the gene effects, both additive and dominant effects were significant. All the non-allelic interaction effects were significant in the crosses. Studies on the isozyme patterns of the enzymes substantiated the results of the disease-incidence experiments in most of the generations. The results indicated that the inheritance of downy mildew disease resistance and the expression of β-1,3-glucanase and peroxidase in pearl millet is not only under the control of additive and dominant genes but are also governed by complex non-allelic interactions. Received: 30 April 2000 / Accepted: 17 October 2000     

A Mass Spectrometric Study for Comparative Analysis and Evaluation of Metabolite Recovery from Plasma by Various Solvent Systems

A solvent system that extracts a maximum number of metabolites belonging to diverse chemical classes from complex biofluids, such as plasma, may offer useful inputs to understand the metabolic and physiological state of an individual. The present study compared seven solvent systems for extraction of metabolites from plasma. The extracts were analyzed by mass spectrometry (MS) and MS/MS (MS2) using a quadrupole time-of-flight liquid chromatography/MS system in positive and negative modes of ionization. Metabolites with molecular mass below 400 were identified using Human Metabolome Database MS2 and MS search interfaces. The acetone/isopropanol (2:1) system yielded promising results in positive ionization mode, as the maximum number of MS and MS2 features was detected in the extract. It was found to be superior in extraction of various classes of metabolites, especially organic acids, nucleosides and nucleoside derivatives, and heterocyclic molecules. Glycerophosphocholines in the mass range of 400–700 were found to be efficiently extracted by the methanol/chloroform/water (8:1:1) system. In negative mode as well, the maximum number of MS2 features was detected in methanol/chloroform/water and acetone/isopropanol extracts. The fingerprints of molecular features obtained in the negative and positive modes differed from each other to a significant extent.     

Regulation of Selenocysteine Incorporation into the Selenium Transport Protein,Selenoprotein P

Selenoproteins are unique as they contain selenium in their active site in the form of the 21st amino acid selenocysteine (Sec), which is encoded by an in-frame UGA stop codon. Sec incorporation requires both cis- and trans-acting factors, which are known to be sufficient for Sec incorporation in vitro, albeit with low efficiency. However, the abundance of the naturally occurring selenoprotein that contains 10 Sec residues (SEPP1) suggests that processive and efficient Sec incorporation occurs in vivo. Here, we set out to study native SEPP1 synthesis in vitro to identify factors that regulate processivity and efficiency. Deletion analysis of the long and conserved 3′-UTR has revealed that the incorporation of multiple Sec residues is inherently processive requiring only the SECIS elements but surprisingly responsive to the selenium concentration. We provide evidence that processive Sec incorporation is linked to selenium utilization and that reconstitution of known Sec incorporation factors in a wheat germ lysate does not permit multiple Sec incorporation events, thus suggesting a role for yet unidentified mammalian-specific processes or factors. The relationship between our findings and the channeling theory of translational efficiency is discussed.     

Genome Sequence of Janibacter hoylei MTCC8307, Isolated from the Stratospheric Air

Janibacter hoylei MTCC8307 was isolated from stratospheric air at an altitude of 41.4 km over Hyderabad, India. Here, we present the draft genome of Janibacter hoylei MTCC8307, which contains 3,139,099 bp with a G+C content of 72.8 mol%, 2,972 protein-coding genes, and 57 structural RNAs.     

Pest management services through conservation of biological control agents: review,case studies and field experiences

ABSTRACT

Conservation biological control is an approach to enhance the efficacy of natural enemies by ensuring their availability in an agro-ecosystem on a long temporal scale. An increased survival often leads to better fecundity and improved behaviour of the natural enemies, which in turn ensures sustainable pest management. This paper, apart from being a concise review of conservation biological control, deals with selected India-specific case studies and field experiences on habitat manipulation and refugia. Results from a Bengaluru-based study during 2012–2015 on conservation biological control in an organic mango ecosystem are also presented. It also dwells briefly on conservation of insectivorous birds and touches upon conservation biocontrol with respect to entomopathogenic microorganisms and plant disease antagonists.     

Genomic and physiological analyses of an indigenous strain, <Emphasis Type="Italic">Enterococcus faecium</Emphasis> 17OM39

The human gut microbiome plays a crucial role in human health and efforts need to be done for cultivation and characterisation of bacteria with potential health benefits. Here, we isolated a bacterium from a healthy Indian adult faeces and investigated its potential as probiotic. The cultured bacterial strain 17OM39 was identified as Enterococcus faecium by 16S rRNA gene sequencing. The strain 17OM39 exhibited tolerance to acidic pH, showed antimicrobial activity and displayed strong cell surface traits such as hydrophobicity and autoaggregation capacity. The strain was able to tolerate bile salts and showed bile salt hydrolytic (BSH) activity, exopolysaccharide production and adherence to human HT-29 cell line. Importantly, partial haemolytic activity was detected and the strain was susceptible to the human serum. Genomics investigation of strain 17OM39 revealed the presence of diverse genes encoding for proteolytic enzymes, stress response systems and the ability to produce essential amino acids, vitamins and antimicrobial compound Bacteriocin-A. No virulence factors and plasmids were found in this genome of the strain 17OM39. Collectively, these physiological and genomic features of 17OM39 confirm the potential of this strain as a candidate probiotic.     

Regulation of low density lipoprotein receptor mRNA levels by estradiol 17β and chorionic gonadotropin in human placenta

Inhibition of synthesis of estradiol 17 by the addition of inhibitors of aromatase, a key enzyme in the biosynthesis of estradiol 17, or addition of tamoxifen - an estrogen receptor antagonist, to human placental minces resulted in an increase in the level of LDL-receptor mRNA. This increase could be blocked by the simultaneous addition of estradiol 17. A concentration dependent effect of estradiol 17 on the level of LDL-receptor mRNA was seen both in first trimester, and term placenta. Addition of human chorionic gonadotropin (hCG) to term placental minces also increased the LDL-receptor mRNA levels. When hCG and cycloheximide were added together, an additive effect was observed. The results obtained in this study suggest that the LDL-receptor mRNA levels in the human placenta are regulated by estradiol 17 and hCG.