217 research outputs found

    Effect of Pleurotus ostreatus fermentation on cocoa pod husk composition: Influence of fermentation period and Mn2+ supplementation on the fermentation process

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    Cocoa pod husk (CPH) is a major agro-industrial residue in Ghana with a potential value as a low-cost unconventional feedstuff for livestock. However, its effective use is limited by poor nutrient composition, mainly due to its high lignocellulose or fibre and also low protein levels. White–rot fungi such as Pleurotus species are bio-catalytic systems for bioconversion processes such as the bioconversion of lignocellulose materials into value-added products including nutritious animal feed.Presence of metals such as manganese (II) ions is reported to enhance fungal enzyme activity in the bioconversion of industrial lignocellulosic residues. The current study investigated the viability of using and optimising a fermentation process involving edible oyster mushroom (Pleurotus ostreatus) as biocatalyst to improve the nutritional status of CPH. Fermentation period and level of manganese (Mn2+) ion supplementation of CPH were the two major factors of the fermentation process evaluated and optimised in this study. Mn supplementation was critical in producing a positive bioconversion effect on CPH by P. ostreatus. Five (5) weeks of P. ostreatus solid-state fermentation of CPH amended with MnCl2 at 0.075% (w/w) concentration, was observed as an economic and optimum treatment to produce positive and significant (P < 0.05) changes in CPH composition, i.e. 36% increment in crude protein and total soluble carbohydrates; 17% reduction in crude fibre and lignin as well as 88% reduction in total tannins

    Development of syrup and “malt-like” drink from Raphia hookeri sap

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    Natural microflora fermentation causes changes in freshly tapped palm sap and therefore makes its storage, transport, and large scale use difficult. This study was aimed at developing stable and value added products, including syrup and non-alcoholic &ldquo;malt-like&rdquo; drink from the sap of palms. The sap of Raphia hookeri collected from &ldquo;evening-to-morning&rdquo;(1700 Hrs-0700 Hrs) and &ldquo;morning-to-afternoon&rdquo; (0700 Hrs-1600 Hrs), respectively, were used in the preparation of syrup. The respective syrups were in turn used in combination with varying proportions of water, sugar, and caramel for the formulation of six(6) palm &ldquo;malt-like&rdquo; drinks from which the best (from sensory evaluation) was carbonated and named Palm Malt. The prepared Palm Malt was compared to commercially popular malt drinks on the market. A nine point hedonic scale (1=like extremely &ndash; 9=dislike extremely) was used by a panel of 56 to evaluate the colour, taste, flavour and after-taste, as well as overall consumer acceptability of the product. Proximate and physicochemical analyses were also carried out on the sap, syrup and Palm Malt using standard procedures. Descriptive statistics (percentages, mean and standard deviation) were derived and data were also subjected to regression analysis to determine relations between parameters. Analysis of variance (ANOVA) was used to determine variations in properties. Results of the proximate analyses showed that the moisture and protein content of the sap samples ranged from 92.96-94.21% and 0.14-0.17% respectively, with an average ash content of 1.53%. That for the syrup ranged from 13.45-15.60% and 0.14-0.17%, respectively, with ash content of 1.70%. Potassium, the principal cation in body cells, was the most abundant mineral in the saps. Physicochemical results: pH and total sugars of the saps were found to be 3.94-4.05, and 6.53-7.57%, respectively; whereas that for the syrups was found to be 3.96-4.13 and 76.70-82.03% respectively. The pH, total soluble solids, total solids and titratable acidity of the developed Palm Malt were found to be 4.94, 14.50%, 15.86%, 0.55%, respectively. The developed Palm Malt was found to be equally acceptable to consumers, in comparison to commercially popular types of malt drinks (P&gt;0.05). This shows that there is potential for economic utilization of palm sap. If exploited, this would contribute to increased income for farmers and industrialists in the regions of Ghana/Africa where palms grow.Keywords: Raphia hookeri, sap, syrup, malt-like drin

    5D gravity and the discrepant G measurements

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    It is shown that 5D Kaluza-Klein theory stabilized by an external bulk scalar field may solve the discrepant laboratory G measurements. This is achieved by an effective coupling between gravitation and the geomagnetic field. Experimental considerations are also addressed.Comment: 13 pages, to be published in: Proceedings of the 18th Course of the School on Cosmology and Gravitation: The gravitational Constant. Generalized gravitational theories and experiments (30 April-10 May 2003, Erice). Ed. by G. T. Gillies, V. N. Melnikov and V. de Sabbata, (Kluwer), 13pp. (in print) (2003

    Trees and shrubs as sources of fodder in Australia

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    Experience with browse plants in Australia is briefly reviewed in terms of their forage value to animals, their economic value to the landholder and their ecological contribution to landscape stability. Of the cultivated species only two have achieved any degree of commercial acceptance (Leucaena leucocephala and Chamaecytisus palmensis). Both of these are of sufficiently high forage value to be used as the sole source of feed during seasonal periods of nutritional shortage. Both are also leguminous shrubs that establish readily from seed. It is suggested that a limitation in their present use is the reliance on stands of single species which leaves these grazing systems vulnerable to disease and insects. Grazing systems so far developed for high production and persistence of cultivated species involve short periods of intense grazing followed by long periods of recovery. Similar management may be necessary in the arid and semi-arid rangelands where palatable browse species are in decline

    Genetic Variations in the Regulator of G-Protein Signaling Genes Are Associated with Survival in Late-Stage Non-Small Cell Lung Cancer

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    The regulator of G-protein signaling (RGS) pathway plays an important role in signaling transduction, cellular activities, and carcinogenesis. We hypothesized that genetic variations in RGS gene family may be associated with the response of late-stage non-small cell lung cancer (NSCLC) patients to chemotherapy or chemoradiotherapy. We selected 95 tagging single nucleotide polymorphisms (SNPs) in 17 RGS genes and genotyped them in 598 late-stage NSCLC patients. Thirteen SNPs were significantly associated with overall survival. Among them, rs2749786 of RGS12 was most significant. Stratified analysis by chemotherapy or chemoradiation further identified SNPs that were associated with overall survival in subgroups. Rs2816312 of RGS1 and rs6689169 of RGS7 were most significant in chemotherapy group and chemoradiotherapy group, respectively. A significant cumulative effect was observed when these SNPs were combined. Survival tree analyses identified potential interactions between rs944343, rs2816312, and rs1122794 in affecting survival time in patients treated with chemotherapy, while the genotype of rs6429264 affected survival in chemoradiation-treated patients. To our knowledge, this is the first study to reveal the importance of RGS gene family in the survival of late-stage NSCLC patients

    Role of structural dynamics at the receptor G protein interface for signal transduction

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    GPCRs catalyze GDP/GTP exchange in the α-subunit of heterotrimeric G proteins (Gαßγ) through displacement of the Gα C-terminal α5 helix, which directly connects the interface of the active receptor (R*) to the nucleotide binding pocket of G. Hydrogen-deuterium exchange mass spectrometry and kinetic analysis of R* catalysed G protein activation have suggested that displacement of α5 starts from an intermediate GDP bound complex (R*•GGDP). To elucidate the structural basis of receptor-catalysed displacement of α5, we modelled the structure of R*•GGDP. A flexible docking protocol yielded an intermediate R*•GGDP complex, with a similar overall arrangement as in the X-ray structure of the nucleotide free complex (R*•Gempty), however with the α5 C-terminus (GαCT) forming different polar contacts with R*. Starting molecular dynamics simulations of GαCT bound to R* in the intermediate position, we observe a screw-like motion, which restores the specific interactions of α5 with R* in R*•Gempty. The observed rotation of α5 by 60° is in line with experimental data. Reformation of hydrogen bonds, water expulsion and formation of hydrophobic interactions are driving forces of the α5 displacement. We conclude that the identified interactions between R* and G protein define a structural framework in which the α5 displacement promotes direct transmission of the signal from R* to the GDP binding pocket

    Hippocampal Gene Expression Analysis Highlights Ly6a/Sca-1 as Candidate Gene for Previously Mapped Novelty Induced Behaviors in Mice

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    In this study, we show that the covariance between behavior and gene expression in the brain can help further unravel the determinants of neurobehavioral traits. Previously, a QTL for novelty induced motor activity levels was identified on murine chromosome 15 using consomic strains. With the goal of narrowing down the linked region and possibly identifying the gene underlying the quantitative trait, gene expression data from this F2-population was collected and used for expression QTL analysis. While genetic variation in these mice was limited to chromosome 15, eQTL analysis of gene expression showed strong cis-effects as well as trans-effects elsewhere in the genome. Using weighted gene co-expression network analysis, we were able to identify modules of co-expressed genes related to novelty induced motor activity levels. In eQTL analyses, the expression of Ly6a (a.k.a. Sca-1) was found to be cis-regulated by chromosome 15. Ly6a also surfaced in a group of genes resulting from the network analysis that was correlated with behavior. Behavioral analysis of Ly6a knock-out mice revealed reduced novelty induced motor activity levels when compared to wild type controls, confirming functional importance of Ly6a in this behavior, possibly through regulating other genes in a pathway. This study shows that gene expression profiling can be used to narrow down a previously identified behavioral QTL in mice, providing support for Ly6a as a candidate gene for functional involvement in novelty responsiveness

    Differential Functional Constraints on the Evolution of Postsynaptic Density Proteins in Neocortical Laminae

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    The postsynaptic density (PSD) is a protein dense complex on the postsynaptic membrane of excitatory synapses that is implicated in normal nervous system functions such as synaptic plasticity, and also contains an enrichment of proteins involved in neuropsychiatric disorders. It has recently been reported that the genes encoding PSD proteins evolved more slowly than other genes in the human brain, but the underlying evolutionary advantage for this is not clear. Here, we show that cortical gene expression levels could explain most of this effect, indicating that expression level is a primary contributor to the evolution of these genes in the brain. Furthermore, we identify a positive correlation between the expression of PSD genes and cortical layers, with PSD genes being more highly expressed in deep layers, likely as a result of layer-enriched transcription factors. As the cortical layers of the mammalian brain have distinct functions and anatomical projections, our results indicate that the emergence of the unique six-layered mammalian cortex may have provided differential functional constraints on the evolution of PSD genes. More superficial cortical layers contain PSD genes with less constraint and these layers are primarily involved in intracortical projections, connections that may be particularly important for evolved cognitive functions. Therefore, the differential expression and evolutionary constraint of PSD genes in neocortical laminae may be critical not only for neocortical architecture but the cognitive functions that are dependent on this structure

    Natural variation of potato allene oxide synthase 2 causes differential levels of jasmonates and pathogen resistance in Arabidopsis

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    Natural variation of plant pathogen resistance is often quantitative. This type of resistance can be genetically dissected in quantitative resistance loci (QRL). To unravel the molecular basis of QRL in potato (Solanum tuberosum), we employed the model plant Arabidopsis thaliana for functional analysis of natural variants of potato allene oxide synthase 2 (StAOS2). StAOS2 is a candidate gene for QRL on potato chromosome XI against the oömycete Phytophthora infestans causing late blight, and the bacterium Erwinia carotovora ssp. atroseptica causing stem black leg and tuber soft rot, both devastating diseases in potato cultivation. StAOS2 encodes a cytochrome P450 enzyme that is essential for biosynthesis of the defense signaling molecule jasmonic acid. Allele non-specific dsRNAi-mediated silencing of StAOS2 in potato drastically reduced jasmonic acid production and compromised quantitative late blight resistance. Five natural StAOS2 alleles were expressed in the null Arabidopsis aos mutant under control of the Arabidopsis AOS promoter and tested for differential complementation phenotypes. The aos mutant phenotypes evaluated were lack of jasmonates, male sterility and susceptibility to Erwinia carotovora ssp. carotovora. StAOS2 alleles that were associated with increased disease resistance in potato complemented all aos mutant phenotypes better than StAOS2 alleles associated with increased susceptibility. First structure models of ‘quantitative resistant’ versus ‘quantitative susceptible’ StAOS2 alleles suggested potential mechanisms for their differential activity. Our results demonstrate how a candidate gene approach in combination with using the homologous Arabidopsis mutant as functional reporter can help to dissect the molecular basis of complex traits in non model crop plants
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