Comparison of the effects of hydrophobicity,amphiphilicity, and α-helicity on the activities of antimicrobial peptides

Multiple linear regression was used to quantify the dependence of the antimicrobial activity of 13 peptides upon three calculated or experimentally determined parameters: mean hydrophobicity, mean hydrophobic moment, and α-helix content. Mean hydrophobic moment is a measure of the amphiphilicity of peptides in an α-helical conformation. Antimicrobial activity was quantified as the reciprocal of the measured minimal inhibitory concentration (MIC) against Escherichia coli. One of the peptides was magainin 2, and the remainder were novel peptides designed for this study. The multiple linear regression results revealed that the amphiphilicity of the peptides was the most important factor governing anti-microbial activity compared to mean hydrophobicity orα-helix content. A better regression cf the data was obtained using In(1/MIC + constant) as the dependent variable than with either 1/MIC or In(1/MIC). These results should be useful in designing peptides with higher antimicrobial activity. © 1995 Wiley-Liss, Inc.     

Two pregnane ester glycosides from Pergularia pallida

Two new pregnane ester glycosides designated as pallidine and pallidinine have been isolated from the dried twigs of Pergularia pallida. Chemical and spectroscopic evidences are consistent with the structure 12,20-di-O-benzoyl sarcostin-3-O-β-d-oleandroside and 12,20-di-O-benzoyl-sarcostin-3-O-β-d-cymaropyranosyl(1 → 4)-β-d-oleandropyranoside for pallidine and pallidinine respectively.     

Relationship of Cob characters with Grain Morphology in Maize (Zea mays,Poaceae)

Twenty varieties of maize (Zea mays, Poaceae) were studied through 11 attributes in three to seven randomly selected plants of each variety with a view to understanding the effect of cob characters on technologically desirable grain qualities. Canonical discriminant analysis showed thatproductivity (determined by total grain weight/cob, cob diameter and average grain weight) was the most discriminating among varieties followed by round grains fraction (represented by whole top and middle flat grains, number of rows and grain count/surface area), middle flat grains (composed of middle flat grains and grain count/surface area) and shape of the cob (determined by shape index, total grain weight/cob and cob diameter), which accounted for 35.1, 18.3, 12.2, and 9.8% of the total variance, respectively. In the light of these results, tentative norms have been suggested to evolve maize varieties of superior technological properties and yet retain high productivity. A cylindrical cob of large diameter with highest number of grains/area and smallest possible number of rows together constituted an ideal combination to achieve the objectives. Such possibilities in the light of available information are discussed.     

A novel baker's yeast mediated C-C bond cleavage reaction

Summary A novel baker's yeast mediated C–C bond cleavage reaction was observed during the biotransformation of dimethone derivative of thiophene-2-carboxaldehyde (II) to give the product 2-(2-thienyl methyl)-5,5 dimethyl cyclohexa 1,3-dione (III) in 47% yield.     

Age-related motor and catecholomine alterations in mice on levodopa supplemented diet

Old mice reared on regular diet show reduced motor activity, decreased basal adenylate cyclase, and increased MAO activities compared to adults. Brain DDC and COMT activities, DA, NE levels and DA-stimulated adenylate cyclase remained unchanged. By contrast, mice fed levodopa for life did not develop decreased motor activity with aging, lived about 50% longer, had slightly elevated whole brain DA and NE levels and failed to develop the expected rise in MAO activity with aging. Levodopa did not alter the number of dopaminergic and muscarinic cholinergic receptors or the adenylate cyclase activity in the striatum during aging. On levodopa, hepatic and renal DA, dopa, and HVA increased but the latter two returned to basal levels by mid life. In liver, DDC was unchanged but MAO tended to be higher in levodopa-fed mice. Thus, motor impairment is an age-related phenomenon in mice associated with selective alterations in brain dopaminergic systems, which may be prevented by dietary levodopa. Extracerebral tissues, through possibly adaptive metabolic mechanisms, play a significant role in regulating brain catecholamines during chronic administration of large doses of levodopa.     

A Synergistic Framework for Evaluating Business Process Improvements

The evaluation, selection, or justification of business process improvements, or business process reengineering efforts, is similar to many strategic initiatives and their justification methodologies. This similarity arises from the fact that there are multiple factors that need to be considered, many of which have long-term and broad implications for an organization. There are many intangible measures and qualitative concerns when evaluating business process improvements. These improvements necessarily have to link to the strategic objectives of the organization. The proposed methodological framework will involve the synthesis of the analytical network process and data envelopment analysis. These two techniques, when used together, can provide subjective and objective evaluations for managerial decision makers. An illustrative example provides some insights into the application of this methodology. Additional issues and research questions are also identified.     

Tomato T2 ribonuclease LE is involved in the response to pathogens

T2 ribonucleases (RNases) are RNA-degrading enzymes that function in various cellular processes, mostly via RNA metabolism. T2 RNase-encoding genes have been identified in various organisms, from bacteria to mammals, and are most diverse in plants. The existence of T2 RNase genes in almost every organism suggests an important biological function that has been conserved through evolution. In plants, T2 RNases are suggested to be involved in phosphate scavenging and recycling, and are implicated in defence responses to pathogens. We investigated the function of the tomato T2 RNase LE, known to be induced by phosphate deficiency and wounding. The possible involvement of LE in pathogen responses was examined. Expression analysis showed LE induction during fungal infection and by stimuli known to be associated with pathogen inoculation, including oxalic acid and hydrogen peroxide. Analysis of LE-suppressed transgenic tomato lines revealed higher susceptibility to oxalic acid, a cell death-inducing factor, compared to the wild type. This elevated sensitivity of LE-suppressed lines was evidenced by visual signs of necrosis, and increased ion leakage and reactive oxygen species levels, indicating acceleration of cell death. Challenge of the LE-suppressed lines with the necrotrophic pathogen Botrytis cinerea resulted in accelerated development of disease symptoms compared to the wild type, associated with suppressed expression of pathogenesis-related marker genes. The results suggest a role for plant endogenous T2 RNases in antifungal activity.     

Decoding the wheat awn transcriptome and overexpressing TaRca1β in rice for heat stress tolerance

Plant Molecular Biology - Role of Rubisco Activase in imparting thermotolerance to the photosynthetic apparatus under high temperature. Thus, to improve the grain filling, we need to fine tune...     

Poly ethylene glycol mediated in vitro screening and physico-biochemical changes induced in mango callus due to moisture stress

Plant Cell, Tissue and Organ Culture (PCTOC) - A method for in vitro screening and selection of drought (moisture stress) tolerant mango calli was developed. Poly ethylene glycol (PEG) (Molecular...