Germination and production ofMacrophomina phaseolina microsclerotia as affected by oxygen and carbon dioxide concentration

Summary Germination of microsclerotia ofMacrophomina phaseolina was observed at O₂ concentrations of 16% or higher in autoclaved soil. Germination was delayed but otherwise unaffected as O₂ decreased from 21 to 16% and was in all cases complete in 32 hours. Laboratory-produced microsclerotia consistently germinated more rapidly and seemed more independent of O₂ concentrations within the range that permitted germination than naturallyproduced microsclerotia.Population changes in soil as measured by microsclerotial counts were inversely correlated with depth of interment and reduced O₂ concentration. Our inability to detect significantly growth responses ofM. phaseolina in non autoclaved soil was apparently related to limited O₂ although other possibilities are discussed.Contribution of the Missouri Agricultural Experiment Station Scientific Journal Series No. 9124.     

Membrane Permeability of Conidia of Bipolaris oryzae

Germinability of the conidia of B. oryzae, after an efflux of substances — both electrolytes and non-electrolytes — was tested in sterilized solutions of plasmolytica and osmotica, ranging from molarity to 10^?12 M. Maximum percent germination was recorded at 10^?8 M concentration regardless of the exogenous supplement in the order KCl >D-glucose >Mannitol >NaCl. Germination was very poor or non-existent in other, higher or lower molarities tested except at 10^?7 M wíth c. 50% germination. In nature the conidia, though nutrient independent, are subject to leaching and likely to lose viability; hence the possible role of the proper osmoticum, basing on the observed fact, in maintenance of membrane equilibrium and germinability of the leached conidia has been discussed.     

Elicitor-induced rosmarinic acid accumulation and secondary metabolism enzyme activities in Solenostemon scutellarioides

This study aimed to improve rosmarinic acid (RA) production in the whole plant culture of Solenostemon scutellarioides through elicitation. Amongst selected elicitors methyl jasmonate (MJ), salicylic acid (SA), and yeast extract (YE) caused significant elevation in RA accumulation. Elicitation with MJ (50 μM) and SA (50 μM) caused almost 1.7 and 1.4-fold increase in RA accumulation, respectively, within day 1. While YE (100 μg ml^?1) elicitation showed highest RA content (~1.5-fold) in day 3. Preceding the elicitor-induced RA accumulation, there was a notable alteration in the specific activities of RA biosynthetic enzymes viz. phenylalanine ammonia lyase, tyrosine aminotransferase, hydroxyl-phenylpyruvate reductase and rosmarinic acid synthase up on MJ (50 μM), SA (50 μM) and YE (100 mg ml^?1) elicitation. Based on differential responses of aforementioned enzymes, RA synthesis was further scaled up through combination of elicitors in pre-optimized doses. In synergy study, at a time exposure with MJ + SA + YE and MJ + SA followed by YE after 24 h has been found to produce significant elevation of RA (2.0 and 1.9-fold, respectively) within 24 h while later maintained a steady state increased level (~1.7 ± 0.2-fold) over control up to day 7.     

Kinetic Enrichment of 34S during Proteobacterial Thiosulfate Oxidation and the Conserved Role of SoxB in S-S Bond Breaking

During chemolithoautotrophic thiosulfate oxidation, the phylogenetically diverged proteobacteria Paracoccus pantotrophus, Tetrathiobacter kashmirensis, and Thiomicrospira crunogena rendered steady enrichment of ³⁴S in the end product sulfate, with overall fractionation ranging between −4.6‰ and +5.8‰. The fractionation kinetics of T. crunogena was essentially similar to that of P. pantotrophus, albeit the former had a slightly higher magnitude and rate of ³⁴S enrichment. In the case of T. kashmirensis, the only significant departure of its fractionation curve from that of P. pantotrophus was observed during the first 36 h of thiosulfate-dependent growth, in the course of which tetrathionate intermediate formation is completed and sulfate production starts. The almost-identical ³⁴S enrichment rates observed during the peak sulfate-producing stage of all three processes indicated the potential involvement of identical S-S bond-breaking enzymes. Concurrent proteomic analyses detected the hydrolase SoxB (which is known to cleave terminal sulfone groups from SoxYZ-bound cysteine S-thiosulfonates, as well as cysteine S-sulfonates, in P. pantotrophus) in the actively sulfate-producing cells of all three species. The inducible expression of soxB during tetrathionate oxidation, as well as the second leg of thiosulfate oxidation, by T. kashmirensis is significant because the current Sox pathway does not accommodate tetrathionate as one of its substrates. Notably, however, no other Sox protein except SoxB could be detected upon matrix-assisted laser desorption ionization mass spectrometry analysis of all such T. kashmirensis proteins as appeared to be thiosulfate inducible in 2-dimensional gel electrophoresis. Instead, several other redox proteins were found to be at least 2-fold overexpressed during thiosulfate- or tetrathionate-dependent growth, thereby indicating that there is more to tetrathionate oxidation than SoxB alone.     

Hydrodynamic interaction between erythrocytes and leukocytes affects rheology of blood in microvessels

Hydrodynamic interaction between erythrocytes (RBC) and leukocytes (WBC) in a microvessel of size 20-40 micron, typical of a postcapillary venule, is studied using a two-dimensional computational model. The model is based on immersed boundary method, and it takes into consideration the particulate nature of blood by explicitly modeling individual blood cell, and cell deformation. Due to their highly flexible nature, RBC drift away from the wall and toward the center of a vessel creating a cell-free layer. It is shown here that the lateral motion of RBC is strongly affected in presence of a WBC, and is dependent on whether the WBC is non-adherent or firmly adhered. When the WBC is non-adherent, some RBC, depending on their initial radial locations and vessel size, may be deflected closer toward the wall, resulting in a decrease in the cell-free layer. The apparent viscosity of the whole blood containing both RBC and WBC is computed, and shown to be much higher than that containing RBC only. The increased viscosity cannot be accounted for by the contribution due to WBC only. This observation is in agreement with a previous in vivo measurement. Here we show that the additional flow resistance is due to the decrease in the cell-free layer resulting from the WBC-RBC interaction. It can be accounted for by a two-layer model of blood when the reduced values of the cell-free layer thickness are used. When the WBC is firmly adhered, RBC easily move away from the wall, and the cell-free layer is not significantly changed. In such cases, the major contribution to whole blood viscosity comes from the WBC alone. The hydrodynamic interaction between WBC and RBC, though it exists, does not contribute significantly when WBC are adhered.     

A review on coronary artery disease,its risk factors,and therapeutics

Coronary artery disease (CAD) is one of the major cardiovascular diseases affecting the global human population. This disease has been proved to be the major cause of death in both the developed and developing countries. Lifestyle, environmental factors, and genetic factors pose as risk factors for the development of cardiovascular disease. The prevalence of risk factors among healthy individuals elucidates the probable occurrence of CAD in near future. Genome-wide association studies have suggested the association of chromosome 9p21.3 in the premature onset of CAD. The risk factors of CAD include diabetes mellitus, hypertension, smoking, hyperlipidemia, obesity, homocystinuria, and psychosocial stress. The eradication and management of CAD has been established through extensive studies and trials. Antiplatelet agents, nitrates, β-blockers, calcium antagonists, and ranolazine are some of the few therapeutic agents used for the relief of symptomatic angina associated with CAD.     

Paraoxonase-2 is a ubiquitously expressed protein with antioxidant properties and is capable of preventing cell-mediated oxidative modification of low density lipoprotein

The oxidation of apolipoprotein B-containing lipoproteins and cell membrane lipids is believed to play an integral role in the development of fatty streak lesions, an initial step in atherogenesis. We have previously shown that two antioxidant-like enzymes, paraoxonase (PON)-1 and PON3, are high density lipoprotein-associated proteins capable of preventing the oxidative modification of low density lipoprotein (LDL) (Reddy, S. T., Wadleigh, D. J., Grijalva, V., Ng, C., Hama, S., Gangopadhyay, A., Shih, D. M., Lusis, A. J., Navab, M., and Fogelman, A. M. (2001) Arterioscler. Thromb. Vasc. Biol. 21, 542-547). In the present study, we demonstrate that PON2 (i) is not associated with high density lipoprotein; (ii) has antioxidant properties; and (iii) prevents LDL lipid peroxidation, reverses the oxidation of mildly oxidized LDL (MM-LDL), and inhibits the ability of MM-LDL to induce monocyte chemotaxis. The PON2 protein was overexpressed in HeLa cells using the tetracycline-inducible ("Tet-On") system, and its antioxidant capacity was measured in a fluorometric assay. Cells that overexpressed PON2 showed significantly less intracellular oxidative stress following treatment with hydrogen peroxide or oxidized phospholipid. Moreover, cells that overexpressed PON2 were also less effective in oxidizing and modifying LDL and, in fact, were able to reverse the effects of preformed MM-LDL. Our results suggest that PON2 possesses antioxidant properties similar to those of PON1 and PON3. However, in contrast to PON1 and PON3, PON2 may exert its antioxidant functions at the cellular level, joining the host of intracellular antioxidant enzymes that protect cells from oxidative stress.     

Relative Reactivity of Ribosyl 2′-OH vs. 3′-OH in Concentrated Aqueous Solutions of Phosphoimidazolide Activated Nucleotides

Phosphoimidazolide activated ribomononucleotides (*pN, see structure) are useful substrates for the non-enzymatic synthesis of oligonucleotides. In the presence of metal ions, aqueous solutions of *pN yield primarily the two internucleotide-linked (pN^2'pN and pN^3'pN) and the pyrophosphate-linked (N^5'ppN) dimers. Small amounts of cyclic dimers and higher oligomers are also produced. In this study the relative reactivity of 2-OH vs. 3-OH was determined from the ratio of the yields of pN^2'pN vs. pN^3'pN. Experiments were performed at 23 °C in the range 7.2 pH 8.4 with substrates that differ in nucleobase (guanosine (G), cytidine (C), uridine (U), and adenosine (A)) and leaving group (imidazole (Im), 2-methylimidazole (2-MeIm) and 2,4-dimethylimidazole (2,4-diMeIm)). Two metal ions (Mg²⁺ or Mn²⁺) were employed as catalysts. The conditions used here, i.e. a substrate concentration in the range 0.1 M to 1.0 M and metal ion concentration in the range 0.05 M to 0.2 M, favor base-stacking interactions. The ratio pN^2'pN: pN^3'pN = 2-5: 3-5 was found independent of nucleobase and typically varied between 2 to 3 indicating that the 2-OH is about 2 to 3 times more reactive than the 3-OH. *pN with Im, compared to 2-MeIm and 2,4-diMeIm leaving group, produce lower yields of internucleotide linked dimers, and a higher pN^2'pN: pN^3'pN ratio. Trends in the data, observed with all three leaving groups, suggest an increase in pN^2'pN: pN^3'pN ratio with decreasing substrate concentration (up to 5.47 with 0.051 M ImpG). The observations are in accord with earlier studies reporting a relative reactivity 2'-5': 3'-5'= 6 to 9 obtained with Im as the leaving group, in dilute nucleotide solutions and under conditions that disfavor stacking. It is speculated that the concentration induced change in the relative reactivity is the result of self-association via base-stacking that enhances selectively the proximity of the 3-OH of one molecule to the reactive P-N bond of an other molecule. The implication of these conclusions for oligomerization/ligation reactions is discussed.