Phylogenetic analysis of isolated biofuel yeasts based on 5.8S-ITS rDNA and D1/D2 26S rDNA sequences

The utilization of agro-industrial wastes such as whey as raw materials for the production of bio-ethanol is gaining importance as a result of the attractiveness of renewable fuel alternatives due to exhaustion of fossil fuel sources coupled with the positive impact to the environment. Here, we report the isolation of two Kluyveromyces spp. designated as BM4 and P41, able to produce ethanol as main fermentation product from fermenting whey. Three different molecular biological approaches including, the RFLP analysis of the 5.8S-ITS rDNA, the sequence of the 5.8S-ITS rDNA region and the sequence of the D1/D2 domain of the 26S rRNA gene were applied for accurate identification. While RFLP analysis of 5.8S-ITS region failed to accurate the differentiation between the two species, sequencing of this region and D1/D2 region of the 26S rRNA gene verified the identification. PCR amplification and sequence analysis of 5.8S-ITS rRNA and D1/D2 domain of the 26S rRNA genes revealed that the isolates BM4 and P41 were highly related to Kluyveromyces marxianus and Kluyveromyces lactis with homology of 99% for both. In addition, phylogenetic analysis indicated that both BM4 and P41 shared a cluster with K. marxianus and K. lactis, respectively. The fermentative performance of both strains on cheese whey to produce ethanol was evaluated at different parameters such as incubation temperature, initial pH, whey sugar concentrations, and yeast concentrations. Results show that the maximum ethanol productions achieved at pH 4.5 and 35 °C were 5.52% and 5.05% for K. marxianus and K. lactis, respectively. Our results demonstrated that K. marxianus and K. Lactis could be recommended for cheese whey bioremediation in the environment and produce renewable biofuel.     

Parallel labeling experiments validate Clostridium acetobutylicum metabolic network model for 13C metabolic flux analysis

In this work, we provide new insights into the metabolism of Clostridium acetobutylicum ATCC 824 obtained using a systematic approach for quantifying fluxes based on parallel labeling experiments and ¹³C-metabolic flux analysis (¹³C-MFA). Here, cells were grown in parallel cultures with [1-¹³C]glucose and [U-¹³C]glucose as tracers and ¹³C-MFA was used to quantify intracellular metabolic fluxes. Several metabolic network models were compared: an initial model based on current knowledge, and extended network models that included additional reactions that improved the fits of experimental data. While the initial network model did not produce a statistically acceptable fit of ¹³C-labeling data, an extended network model with five additional reactions was able to fit all data with 292 redundant measurements. The model was subsequently trimmed to produce a minimal network model of C. acetobutylicum for ¹³C-MFA, which could still reproduce all of the experimental data. The flux results provided valuable new insights into the metabolism of C. acetobutylicum. First, we found that TCA cycle was effectively incomplete, as there was no measurable flux between α-ketoglutarate and succinyl-CoA, succinate and fumarate, and malate and oxaloacetate. Second, an active pathway was identified from pyruvate to fumarate via aspartate. Third, we found that isoleucine was produced exclusively through the citramalate synthase pathway in C. acetobutylicum and that CAC3174 was likely responsible for citramalate synthase activity. These model predictions were confirmed in several follow-up tracer experiments. The validated metabolic network model established in this study can be used in future investigations for unbiased ¹³C-flux measurements in C. acetobutylicum.     

Association between FABP2 Ala54Thr polymorphisms and type 2 diabetes mellitus risk: a HuGE Review and Meta‐Analysis

Many studies have examined the association between the FABP2 (rs1799883) Ala54Thr gene polymorphism and type 2 diabetes mellitus risk (T2DM) in various populations, but their results have been inconsistent. To assess this relationship more precisely, A HuGE review and meta‐analysis were performed. The PubMed and CNKI database was searched for case‐control studies published up to April 2014. Data were extracted and pooled odds ratios (OR) with 95% confidence intervals (CI) were calculated. Ultimately, 13 studies, comprising 2020 T2DM cases and 2910 controls were included. Overall, for the Thr carriers (Ala/Thr and Thr/Thr) versus the wild‐type homozygotes (Ala/Ala), the pooled OR was 1.18 (95% CI = 1.04–1.34, P = 0.062 for heterogeneity), for Thr/Thr versus Ala/Ala the pooled OR was 1.17 (95% CI = 1.05–1.41 P = 0.087 for heterogeneity). In the stratified analysis by ethnicity, the significantly risks were found among Asians but not Caucasians. This meta‐analysis suggests that the FABP2 (rs1799883) Ala54Thr polymorphisms are associated with increased susceptibility to T2DM risk among Asians but not Caucasians.     

Modified speciation scheme for inorganic phosphate in lake sediments

Abstract

Speciation schemes for phosphate in soils or sediments tend to yield results which are ‘conditional’ and subject to error. In the proposed modified scheme, secondary phosphate-cation interactions have been minimised by including a cation exchange resin in the extraction system; re-sorption errors have been reduced by using low (1:400) solid to liquid extractant ratios; and slow dissolution rates have been balanced by using longer extraction times (up to 62 h). Variables examined during scheme development included the effect of varying sample weights, extraction time, reagent type, exchanger type, exchanger to sample weight ratios and pH on the amount of phosphate released from a polluted lake sediment. It was found that the amount of inorganic phosphate released by chemical reagents (or by cation exchanger) varied markedly with system pH, being greatest in the pH 2 to 3 region, decreasing to near zero in the pH 4 to 6 zone, and then rising to an intermediate value at pH > 8. Monitoring of the Ca, Mg, Fe and Al released into the various solutions (or transferred into the exchanger phase) indicated that one cannot clearly distinguish between phosphate initially present in association with alkaline earth compounds or iron-rich matrix components. The advantages and limitations of this ‘differential solubility’ scheme have been considered and alternative approaches briefly reviewed.     

Control of root-knot nematode,Meloidogyne incognita and reniform nematode,Rotylenchulus reniformis on pigeonpea and linseed

Abstract

Pigeonpea (Cajanus cajan) and linseed (Linum usitatissimum) are susceptible to Meloidogyne incognita and Rotylenchulus reniformis nematodes. Reduction in different growth parameters (length and weight of plant, number of pods), bulk density of pigeonpea stem, oil content of linseed, chlorophyll content of leaf and water absorption of roots caused by M. incognita and R. reniformis were statistically significant. Similar effects were also observed in plants raised from seeds soaked in different concentrations of water soluble fractions (WSF) of rice polish and pyridoxine solutions, however, the reductions were of a comparatively lesser extent. Higher concentrations of the solutions were more effective when compared to lower ones and pyridoxine was more beneficial than WSF for improving plant growth and reducing disease incidence.     

The Ca2+ channel β2 subunit is selectively targeted to the axon terminals of supraoptic neurons

The assembly of high voltage-activated Ca²⁺ channels with different β subunits influences channel properties and possibly subcellular targeting. We studied β subunit expression in the somata and axon terminals of the magnocellular neurosecretory cells, which are located in the supraoptic nucleus (SON) and neurohypophysis, respectively. Antibodies directed against the 4 Ca_Vβ subunits (Ca_Vβ₁-Ca_Vβ₄) were used for immunoblots and for immunostaining of slices of these two tissues. We found that all 4 β subunits are expressed in both locations, but that Ca_Vβ₂ had the highest relative expression in the neurohypophysis. These data suggest that the Ca_Vβ₂ subunit is selectively targeted to axon terminals and may play a role in targeting and/or regulating the properties of Ca²⁺ channels.     

Peering into the Dynamics of Social Interactions: Measuring Play Fighting in Rats

Play fighting in the rat involves attack and defense of the nape of the neck, which if contacted, is gently nuzzled with the snout. Because the movements of one animal are countered by the actions of its partner, play fighting is a complex, dynamic interaction. This dynamic complexity raises methodological problems about what to score for experimental studies. We present a scoring schema that is sensitive to the correlated nature of the actions performed. The frequency of play fighting can be measured by counting the number of playful nape attacks occurring per unit time. However, playful defense, as it can only occur in response to attack, is necessarily a contingent measure that is best measured as a percentage (#attacks defended/total # attacks X 100%). How a particular attack is defended against can involve one of several tactics, and these are contingent on defense having taken place; consequently, the type of defense is also best expressed contingently as a percentage. Two experiments illustrate how these measurements can be used to detect the effect of brain damage on play fighting even when there is no effect on overall playfulness. That is, the schema presented here is designed to detect and evaluate changes in the content of play following an experimental treatment.