Influence of metalaxyl on Glomus fasciculatum associated with wheat (Triticum aestivum L)

Soil incorporation of metalaxyl [methyl N-(2-methoxyacetyl)-N-(2,6,xylyl)-DL-alaninate] significantly enhanced root colonization of the vesicular-arbuscular (VA) mycorrhizal fungi Glomus fasciculatum associated with wheat. The stimulatory response of VA mycorrhizal fungi to low concentration of metalaxyl resulted in increased plant biomass production, nutrient uptake and grain yield of wheat. However, higher concentrations of metalaxyl, particularly 2.5 ppm of metalaxyl affected the mycorrhizal infection and seed yield of wheat, Addition of urban compost to an extent ameliorated the toxic effect of fungicide on VA mycorrhizal colonization, plant growth and yield of wheat when compared to unamended soil.

Euglena sp as a suitable source of lipids for potential use as biofuel and sustainable wastewater treatment

Prolific algal growth in sewage ponds with high organic loads in the tropical regions can provide cost-effective and efficient wastewater treatment and biofuel production. This work examines the ability of Euglena sp. growing in wastewater ponds for biofuel production and treatment of wastewater. The algae were isolated from the sewage treatment plants and were tested for their nutrient removal capability. Compared to other algae, Euglena sp. showed faster growth rates with high biomass density at elevated concentrations of ammonium nitrogen (NH4-N) and organic carbon (C). Profuse growth of these species was observed in untreated wastewaters with a mean specific growth rate (mu) of 0.28 day(-1) and biomass productivities of 132 mg L-1 day(-1). The algae cultured within a short period of 8 days resulted in the 98 % removal of NH4-N, 93 % of total nitrogen 85 % of ortho-phosphate, 66 % of total phosphate and 92 % total organic carbon. Euglenoids achieved a maximum lipid content of 24.6 % (w/w) with a biomass density of 1.24 g L-1 (dry wt.). Fourier transform infrared spectra showed clear transitions in biochemical compositions with increased lipid/protein ratio at the end of the culture. Gas chromatography and mass spectrometry indicated the presence of high contents of palmitic, linolenic and linoleic acids (46, 23 and 22 %, respectively), adding to the biodiesel quality. Good lipid content (comprised quality fatty acids), efficient nutrient uptake and profuse biomass productivity make the Euglena sp. as a viable source for biofuel production in wastewaters.

A linear root water uptake model

A model of root water extraction is proposed, in which a linear variation of extraction rate with depth is assumed. Five crops are chosen for simulation studies of the model, and soil moisture depletion under optimal conditions from different layers for each crop is calculated. Similar calculations are also made using the constant extraction rate model. Rooting depth is assumed to vary linearly with potential evapotranspiration for each crop during the vegetative phase. The calculated depletion patterns are compared with measured mean depletion patterns for each crop. It is shown that the constant extraction rate model results in large errors in the prediction of soil moisture depletion, while the proposed linear extraction rate model gives satisfactory results. Hypothetical depletion patterns predicted by the model in combination with a moisture tension-dependent sink term developed elsewhere are indicated.

Structure, energetics and diffusion properties of isomers of trimethyl benzene in beta zeolite: Uptake and Monte Carlo simulation study

A Monte Carlo study along with experimental uptake measurements of 1,2,3-trimethyl benzene, 1,2,4-trimethyl benzene and 1,3,5-trimethyl benzene (TMB) in beta zeolite is reported. The TraPPE potential has been employed for hydrocarbon interaction and harmonic potential of Demontis for modeling framework of the zeolite. Structure, energetics and dynamics of TMB in zeolite beta from Monte Carlo runs reveal interesting information about the diameter, properties of these isomers on confinement. Of the three isomers, 135TMB is supposed to have the largest diameter. It is seen TraPPE with Demontis potential predicts a restricted motion of 135TMB in the channels of zeolite beta.Experimentally, 135TMB has the highest transport diffusivity whereas MID results suggest this has the lowest self diffusivity. (C) 2009 Elsevier Inc. Ail rights reserved.

Simian Virus 40 Small T Antigen Activates AMPK and Triggers Autophagy To Protect Cancer Cells from Nutrient Deprivation

As tumors grow larger, they often experience an insufficient supply of oxygen and nutrients. Hence, cancer cells must develop mechanisms to overcome these stresses. Using an in vitro transformation model where the presence of the simian virus 40 (SV40) small T (ST) antigen has been shown to be critical for tumorigenic transformation, we investigated whether the ST antigen has a role to play in regulating the energy homeostasis of cancer cells. We find that cells expressing the SV40 ST antigen (+ST cells) are more resistant to glucose deprivation-induced cell death than cells lacking the SV40 ST antigen (-ST cells). Mechanistically, we find that the ST antigen mediates this effect by activating a nutrient-sensing kinase, AMP-activated protein kinase (AMPK). The basal level of active, phosphorylated AMPK was higher in +ST cells than in -ST cells, and these levels increased further in response to glucose deprivation. Additionally, inhibition of AMPK in +ST cells increased the rate of cell death, while activation of AMPK in -ST cells decreased the rate of cell death, under conditions of glucose deprivation. We further show that AMPK mediates its effects, at least in part, by inhibiting mTOR (mammalian target of rapamycin), thereby shutting down protein translation. Finally, we show that +ST cells exhibit a higher percentage of autophagy than -ST cells upon glucose deprivation. Thus, we demonstrate a novel role for the SV40 ST antigen in cancers, where it functions to maintain energy homeostasis during glucose deprivation by activating AMPK, inhibiting mTOR, and inducing autophagy as an alternate energy source.

Mechanism of glycine uptake by the silk glands of the silkworm Bombyx mori L

The transport of glycine in vitro into the silk glands of the silkworm has been studied. Glycine accumulates inside the tissue to a concentration higher than that present outside, indicating an active transport mechanism. The kinetics of uptake show a biphasic curve and two apparent Km values for accumulation, 0.33 mM and 5.00 mM. The effect of inhibitors on the energy metabolism of glycine transport is inconclusive. Exchange studies indicate the existence of two pools inside the gland, one that is easily removed by exchange and osmotic shock, and the other which is not. The results obtained conform with the carrier model of Britten and McClure concerning the amino-acid pool in E. coli.

Effect of some "strong" excitants of central neurones on the uptake of L-glutamate and L-aspartate by synaptosomes

"Strong" excitants of central neurones such as β N-oxalyl L α,β-diaminopropionic acid (ODAP), N-methyl-D-aspartic acid (NMDA) and kainic acid (KA) were found to inhibit the high affinity uptake of glutamate and aspartate in synaptosomes isolated from young rat brain. The potency of these "strong" excitants as convulsants appear to parallel their ability to inhibit glutamate uptake by synaptosomes. The data suggest the possibility that the convulsive effect of these "strong" excitants could be mediated by glutamate/aspartate.

Effect of beta-n-oxalyl-L-alpha, beta-diaminopropionic acid on glutamate uptake by synaptosomes

THE unusual amino acid beta-N-oxalyl-L-alpha, beta-diaminopropionic acid (ODAP), isolated from the seeds of Lathyrus sativus is a potent neurotoxin1−3. It produces biochemical changes in the brain typical of an excitant amino acid and is implicated in the aetiology of human neurolathyrism caused by eating the seeds of L. sativus 4−6. It may act as a glutamate antagonist: ODAP inhibits glutamate oxidation7 possibly by inhibiting glutamate uptake in bovine brain mitochondria; it also acts as a competitive inhibitor of glutamate uptake in certain strains of yeast8, and a similar process might occur at the synaptic level. Any effect of ODAP on glutamate uptake at synapses is significant in view of the neurotransmitter function of glutamate, which seems to be neuroexcitory as well as neurotoxic9−12. But Balcar and Johnston13 have shown with rat brain slices that ODAP does not inhibit the glutamate uptake by the high affinity system.

Rice husk filtrate as a nutrient medium for the growth of Desulfotomaculum nigrificans: characterisation and sulfate reduction studies

The filtrate obtained by interacting a known amount of rice husk with deionised, Milli-Q water was assessed as a carbon source and nutrient medium for the growth of Desulfotomaculum nigrificans, a typical sulfate-reducing bacterium. The filtrate contained essential growth constituents such as magnesium, potassium, phosphorous apart from calcium, sodium, chloride and sulfate ions. Based on the 1H and 13C NMR characterization studies, the organic composition of the components dissolved from the rice husk, was found to be: (i) 66% lignocellulosic material, (ii) 24% xylose + arabinose and (iii) 10% galactose. The growth studies indicated a 15-fold increase in the bacterial cell number in about 20 days. Nearly 81% and 66% reduction in sulfate concentration could be achieved in about 28 days, from the solutions containing initial sulfate concentrations of 550 mg/l and 1200 mg/l respectively. In both the cases studied, the iron concentration could be reduced by over 85%.

Synthesis of neoglycopeptides and analyses of their biodistributionin vivo to identify tissue specific uptake and novel putative membrane lectins

Complex typeN-linked oligosaccharides derived from fetuin, fibrinogen and thyroglobulin were coupled to acetyltyrosine affording a series of neoglycopeptides with retention of terminal structures and the beta-anomeric configuration of their reducing endN-acetylglycosamine residue. The neoglycopeptides thus synthesized could be labelled to high specific activities with125I in the aromatic side chain of tyrosine. Analysis of the fate of these neoglycopeptides in conjunction with inhibition with asialofetuin and oligosaccharides of defined structure in micein vivo revealed the uptake of galactosylated biantennary compound by kidneys, in addition to the known itinerary of triantennary galactosylated complex oligosaccharide from fetuin to liver and the galactosylated biantennary chain with fucosylation in the core to bone marrows. On the other hand, the agalacto, aglucosamino biantennary chains with and without fucosylation in the core region are taken up by submaxillary glands while the conserved trimannosyl core with fucose is primarily concentrated in stomach tissue. These studies thus define new routes for the uptake of complexN-linked glycans and also subserve to identify lectins presumably involved in their recognition.

Chloromycetin in the nutrition of the silkworm Bombyx mori L.-III. Influence on gut weight, oxygen uptake, and glucose absorption

Administration of chloromycetin has been found to enhance the oxygen uptake of the gut of the silkworm. The possibility that this increase might have been due to a thinning of the gut wall has been ruled out since the reduction in gut weight set in much later. Although glucose ultilization by the gut has been found to be increased in vitro, increase in oxygen uptake has not been affected in the presence of glucose. The possibility of a hormonal stimulation has been discussed.

Chloromycetin in the nutrition of the silkworm Bombyx mori L.-III. Influence on gut weight, oxygen uptake, and glucose absorption

Administration of chloromycetin has been found to enhance the oxygen uptake of the gut of the silkworm. The possibility that this increase might have been due to a thinning of the gut wall has been ruled out since the reduction in gut weight set in much later. Although glucose ultilization by the gut has been found to be increased in vitro, increase in oxygen uptake has not been affected in the presence of glucose. The possibility of a hormonal stimulation has been discussed.

Mechanism of glycine uptake by the silk glands of the silkworm Bombyx mori L.

The transport of glycine in vitro into the silk glands of the silkworm has been studied. Glycine accumulates inside the tissue to a concentration higher than that present outside, indicating an active transport mechanism. The kinetics of uptake show a biphasic curve and two apparent Km values for accumulation, 0.33 mM and 5.00 mM. The effect of inhibitors on the energy metabolism of glycine transport is inconclusive. Exchange studies indicate the existence of two pools inside the gland, one that is easily removed by exchange and osmotic shock, and the other which is not. The results obtained conform with the carrier model of Britten and McClure concerning the amino-acid pool in E. coli.

Hormones and Cuscuta development: IAA uptake transport and metabolism in relation to growth in the absence and presence of applied cytokinin

Transport of 1-14C-IAA in successive stem segments of Cuscuta was strictly basipetal in growing and non growing regions of the vine with a flux velocity of 10-12 mm/h (intercept method). This transport showed a distinct peaked profile, increasing from a low value at 10 mm from the apex to a maximum between 50 and 90 mm before declining to a low value again around 160 mm at which elongation growth ceased. The IAA transport profile paralleled the in vivo growth rate profile, though the latter peaked ahead of transport. A better correlation was observed between the profile of growth responsiveness of the vine to exogenous IAA application and the profile of IAA transport. Growth responsiveness was determined as the differential in growth rate of stem segments in vitro in the absence and presence of growth optimal concentration of IAA (10 μm). Retention of exogenous IAA in the stem was maximal where transport decreased, and this coincided with the region of maximal conjugation of applied 1-14C-IAA to aspartic acid to form indoleacetylaspartate (IAAsp). In addition to aspartate, IAA was conjugated to a small extent to an unidentified compound. IAA destruction by decarboxylation was greatest where transport was low, particularly in the nongrowing region, where lignification occurred (i.e., beyond 180 mm). At concentrations up to 20 μM, a pulse of 1-14C-IAA chased by "cold" IAA moved as a peak (with a peak displacement velocity of 12-18 mm/h) in the "growth" region of the vine, but became diffusionlike where growth either fell off steeply or ceased. At a higher (50 μM) IAA concentration, though uptake was not saturated, transport in the growth region became diffusionlike, indicating saturation of the system. Reduced IAA flux in the region where growth responsiveness to IAA declined coincided with the region of increased IAA conjugation. However, it cannot be concluded whether increased IAA conjugation was the cause or effect of decreased IAA flux. Application of benzyladenine to the vines in vivo, a treatment that elicited haustoria formation by 72 h, resulted in the inhibition of both IAA transport and elongation growth rate in the subapical region. In vitro treatment of vine segments with BA similarly increased IAA retention and decreased IAA transport. IAA loss was suppressed, and conjugation to IAAsp was enhanced. © 1989 Springer-Verlag New York Inc.