Reduction of Some Enzymes Produced by Irradiated Fungal Strains Isolated from Certain Medicinal Plants

Medicinal plants normally carry high bioburden due to their origin, offering potentials hazards to the consumer. Fungal extracellular enzymes play a role in biodeterioration of medicinal plants and undesirably effect human health cause immunotoxigenic diseases. Ten different medicinal plants were screened for their mold contamination. The isolates were identified as genera Aspergillus, Alternaria, Cladosporium and Penicillum, they tested for their enzymatic activities (protease, cellulase and lipase). All isolates were able to produce enzymes under study in a varying degree. Of the fungal isolates , Asp. niger and Asp. flavus showed high protease activity. Whereas P. roquefortii and Asp. parasiticus were the more potent strains producing cellulase. Lipase was found to be highly produced by Asp. fumigatus and P. italicum . The present study presumes to monitor the fungal growth and enzymatic activity in relation to gamma irradiation. The results showed that, the log number of survivors was found to be inversely proportional to the irradiation dose. 6.0 and 4.0 kGy resulted in complete inhibition the growth of  highly protease produces (Asp. niger and Asp.flavus). While,  P. roquefortii and Asp. parasiticus which highly produce cellulase were inhibited at 4.0 and 6.0 kGy, respectively. On the other hand, Asp.fumigatus and P. italicum which highly produce lipase were inhibited at dose 4.0 and 6.0 kGy, respectively. Subleathal doses of gamma- irradiation resulted in high significant reduction of enzymes production. The stability of acquired character for the strains under study which were exposed to gamma-irradiation was studied. Statistical analysis revealed that, the enzyme activities estimated after 6 months of storage gave difference data between the strains under study. This study indicates that gamma irradiation is an effective treatment for reduction of fungi contaminating medicinal plants as well as its ability to produce some enzymes. Key words: medicinal plants, fungal isolates, enzymatic activity, gamma irradiation

Gaudin models solver based on the Bethe ansatz/ordinary differential equations correspondence

We present a numerical approach which allows the solving of Bethe equations whose solutions define the eigenstates of Gaudin models. By focusing on a new set of variables, the canceling divergences which occur for certain values of the coupling strength no longer appear explicitly. The problem is thus reduced to a set of quadratic algebraic equations. The required inverse transformation can then be realized using only linear operations and a standard polynomial root finding algorithm. The method is applied to Richardson's fermionic pairing model, the central spin model and generalized Dicke model.Comment: 10 pages, 3 figures, published versio

Influence of Interface on epoxy/clay Nanocomposites: 1. Morphology Structure

AbstractA current challenge for the material scientists nowadays is the design and invention of new material systems that have a low weight, low cost but possess high levels of mechanical performance, good design flexibility and processability. This challenge has arisen due to the modern trend of utilizing lightweight and high performance materials, which has the potential to contribute to the advanced future applications, such as in aerospace, automotives, biotechnology, electronics and many more. In this new world, polymer nanocomposites have developed to be one of the latest evolutionary steps in the polymer technology, besides showing a great deal to become the most versatile industrial advanced materials. In comparison with conventional composites, nanocomposites demonstrate significantly higher levels of mechanical performance with less content of particles. The particle interface has been known to play a critical role in conventional composites. Nevertheless, the understanding of the role of interface in morphology polymer nanocomposites remains in its infancy. Thus, this study aims to develop a series of epoxy polymer layered-clay nanocomposites with levels of interface strength by designing chemical reactions or physical entanglements between nanoparticles and matrix polymer. In order to achieve this goal, three types of modifier were adopted: ethanolamine (denoted eth), Jeffamine M2070 (m27) and Jeffamine XTJ502 (xtj). The interface strength was identified through the morphology observation such as X-ray diffraction and scanning electron microscopy of fracture surface, in which later are correlated with various mechanical properties of nanocomposites

Market Integration Shape Organic Farmers’ Organisation

Increasing consumption of organic products in globalised food chains will require the involvement of thousands more smallholder farmers in many regions of the world. A study of Egypt, China and Uganda identified the three key factors of property rights regimes, cultural differences and social organisation as determents of the supply chain organization and farmers’ degree of direct integration in the export markets. Patterns are emerging where smallholder farmers are being socially and economically linked to larger farmers who may do some processing before the raw materials are handed over to the contracting company. Where transactions costs are high, local communities may develop and contract out the land directly to exporting companies who farm using employees. Four organisational patterns are identified which each leads to different types of livelihood benefits for the producers; preliminary results indicate that income and a reliable market access is the dominant benefits

Interface modification of clay and graphene platelets reinforced epoxy nanocomposites: a comparative study

The interface between the matrix phase and dispersed phase of a composite plays a critical role in influencing its properties. However, the intricate mecha-nisms of interface are not fully understood, and polymer nanocomposites are no exception. This study compares the fabrication, morphology, and mechanical and thermal properties of epoxy nanocomposites tuned by clay layers (denoted as m-clay) and graphene platelets (denoted as m-GP). It was found that a chemical modification, layer expansion and dispersion of filler within the epoxy matrix resulted in an improved interface between the filler mate-rial and epoxy matrix. This was confirmed by Fourier transform infrared spectroscopy and transmission electron microscope. The enhanced interface led to improved mechanical properties (i.e. stiffness modulus, fracture toughness) and higher glass transition temperatures (Tg) compared with neat epoxy. At 4 wt% m-GP, the critical strain energy release rate G1c of neat epoxy improved by 240 % from 179.1 to 608.6 J/m2 and Tg increased from 93.7 to 106.4 �C. In contrast to m-clay, which at 4 wt%, only improved the G1c by 45 % and Tg by 7.1 %. The higher level of improvement offered by m-GP is attributed to the strong interaction of graphene sheets with epoxy because the covalent bonds between the carbon atoms of graphene sheets are much stronger than silicon-based clay

Peptidomimetic and Non- Peptidomimetic Derivatives as Possible SARS-CoV-2 Main Protease (Mpro) Inhibitors

To design novel inhibitors of the SARS-CoV-2 main protease (Mpro), we investigated the binding mode of the recently reported α-ketoamide inhibitors of this enzyme. Following, we utilized in-silico screening to identify 168 peptidomimetic and non-peptidomimetic compounds that are high probability Mpro binding candidates. The compounds were synthesized in 5 to 10 mg for initial screening for their potential inhibition of Mpro using Fluorescence Resonance Energy Transfer (FRET) assay. The study was conducted using the main protease, MBP-tagged (SARS-CoV-2) Assay Kit (BPS Bioscience, #79955-2), and the fluorescence due to enzymatic cleavage of substrate measured using BMG LABTECH CLARIOstar™, a fluorescent microplate reader, with an excited/emission wavelength of 360 nm/460 nm, respectively. The FRET assay showed 29 compounds to exhibit lower fluorescence compared to the positive control, indicating inhibitory activity, with three of the compounds exhibiting over 50% enzymatic inhibition. The assay average scores were plotted as dose inhibition curves using variable parameter nonlinear regression to calculate the IC50 values. To design more potent inhibitors, an in-silico molecular docking simulation using the SARS-CoV-2 Mpro crystal structure was conducted to investigate on a molecular level the key binding residues at the active site, as well as the possible binding modes and affinity of the lead inhibitors. Additionally, an in-silico study of the compounds\u27 molecular properties and physicochemical profiles was performed to predict their pharmacokinetic properties and assess their suitability as potential orally active drug candidates.https://scholarscompass.vcu.edu/gradposters/1139/thumbnail.jp

Genic SNP markers and legume synteny reveal candidate genes underlying QTL for Macrophomina phaseolina resistance and maturity in cowpea [Vigna unguiculata (L) Walp.]

<p>Abstract</p> <p>Background</p> <p><it>Macrophomina phaseolina </it>is an emerging and devastating fungal pathogen that causes significant losses in crop production under high temperatures and drought stress. An increasing number of disease incidence reports highlight the wide prevalence of the pathogen around the world and its contribution toward crop yield suppression. In cowpea [<it>Vigna unguiculata </it>(L) Walp.], limited sources of low-level host resistance have been identified, the genetic basis of which is unknown. In this study we report on the identification of strong sources of host resistance to <it>M. phaseolina </it>and the genetic mapping of putative resistance loci on a cowpea genetic map comprised of gene-derived single nucleotide polymorphisms (SNPs) and amplified fragment length polymorphisms (AFLPs).</p> <p>Results</p> <p>Nine quantitative trait loci (QTLs), accounting for between 6.1 and 40.0% of the phenotypic variance (R²), were identified using plant mortality data taken over three years in field experiments and disease severity scores taken from two greenhouse experiments. Based on annotated genic SNPs as well as synteny with soybean (<it>Glycine max</it>) and <it>Medicago truncatula</it>, candidate resistance genes were found within mapped QTL intervals. QTL <it>Mac-2 </it>explained the largest percent R²and was identified in three field and one greenhouse experiments where the QTL peak co-located with a SNP marker derived from a pectin esterase inhibitor encoding gene. Maturity effects on the expression of resistance were indicated by the co-location of <it>Mac-6 </it>and <it>Mac-7 </it>QTLs with maturity-related senescence QTLs <it>Mat-2 </it>and <it>Mat-1</it>, respectively. Homologs of the <it>ELF4 </it>and <it>FLK </it>flowering genes were found in corresponding syntenic soybean regions. Only three <it>Macrophomina </it>resistance QTLs co-located with delayed drought-induced premature senescence QTLs previously mapped in the same population, suggesting that largely different genetic mechanisms mediate cowpea response to drought stress and <it>Macrophomina </it>infection.</p> <p>Conclusion</p> <p>Effective sources of host resistance were identified in this study. QTL mapping and synteny analysis identified genomic loci harboring resistance factors and revealed candidate genes with potential for further functional genomics analysis.</p