Pathogenic potential of Listeria monocytogenes isolated from cattle faeces in Adoekiti

Listeria monocytogenes is an opportunistic food-borne pathogen causing listeriosis especially among immune-compromised persons. Its high rate of morbidity and mortality has classed the organism among the top watch list in foods. It is known to produce several virulence factors which aid its survival in harsh conditions and its dissemination within host cells. The pathogenicity of L. monocytogenes, isolated from cattle faeces in Ado-Ekiti, was determined in Wister albino rats for two weeks and the relative virulence was calculated. Rats were challenged with isolates producing listeriolysin O and phospholipase orally, intraperitoneally and subcutaneously. Biochemical parameters and haematoxylin and eosin (H and E) stained sections of selected organs were examined for significant changes (p < .05) and histopathological effects post-experiment. Relative virulence was recorded at 0% with rats showing no signs of infection or death. However, significant changes in total protein, lipid profile and some selected antioxidant enzymes, as well as cytological changes in the examined H and E sections of organs showed that an infection had occurred. Bacteria may have however been eradicated by the immune-competent rats. This study therefore concludes that isolates may be pathogenic especially for persons tagged ‘high risk’ due to low immunity.Keywords:  L. monocytogenes, listeriosis, pathogenicity, histopathology, cattle feace

In vitro and in vivo antimicrobial activity of partially purified enterocin produced by Enterococcus faecalis and its application in wound healing

Background: The recent global upsurge in antibiotic resistance among bacteria associated with wounds has contributed to high treatment failures in wound management. Enterocin are produced by enterococci and has been reported to inhibit the growth of many bacteria including those associated with wound infections.Objectives: In this study, antibacterial and physico-chemical properties of partially purified enterocin (PPE) from Enterococcus faecalis was determined. Also, the possible application of the enterocin in wound management was evaluated.Materials and Methods: Eight different enterocin were tested and that with highest antibacterial (E3) was partially purified using standard methods. The molecular weight of the PPE was determined by sodium dodecyl sulphate polyacrylamide gel electrophoresis after which the in vitro anti-Staphylococcus aureus potential of the PPE was determined.Results: Enterocin (E3) was effective against Staphylococcus aureus, Klebsiella pneumoniae, Enterobacter cloaca, Listeria monocytogenes and Proteus vulgaris. The activity of the E3 was very prominent at pH of 4 and 8. The molecular size of the isolated enterocin was 5.5 KDa. The photomicrograph of the skin tissue of the skin treated with partially purified enterocin for day 7showed epidermis covered by atrophic stratified squamous epithelium. A synergistic interaction was noticed when Eusol was used with the enterocin.Conclusions: From this study, enterocin from E. faecalis has a low molecular weight and inhibited bacteria isolates from wound and also aids physiological healing of wound.The antibacterial potency of this bacteriocin indicates that it is an alternative therapeutic agent that can be employed in wound care and management.Keywords: Enterocin, Enterococcus faecalis, wounds, bacteriocin, Staphylococcus aureus, ski

Nutritional profile and yield of oyster mushroom cultivated on selected agricultural wastes

Research on mushroom production and products is gaining more grounds globally and in particular Nigeria. This study was carried out to determine nutritional relationship between the substrate used for cultivation and the fruiting body on each of the substrates. Agro-wastes, namely: palm ( Elaeis guineensis ) fruit shaft, plantain ( Musa paradisiaca ) leaves, sawdust and kenaf ( Hibiscus ) stem, were assessed for suitability as substrates for cultivation of oyster mushroom ( Pleurotus floridanus Singer ). The spawn of the mushroom was used to inoculate each of the substrates, using a complete randomised design, with five replicates for each substrate. Results showed that all the substrates supported mycelia growth and development of fruiting bodies of the fungus. There were significant differences (P<0.05) among substrates in terms of number of days to complete mycelia run, with the least recorded in palm fruit shaft (25.20), and the highest in kenaf (32.40). Total yield also differed significantly (P<0.05), with the highest in palm fruit shaft (51.4 g 100 g-1) and lowest in plantain leaves (6.0 g 100 g-1). There was also significant difference (P<0.05) in the nutritional content of fruiting bodies, the highest fat content being on plantain leaves (1.72 g 100 g-1) and the lowest on palm fruit shaft (0.55 g 100 g-1). The trend was similar for mushroom substrates, plantain leaves having (2.55 g 100 g-1) and palm fruit shaft, (0.41g 100 g-1). Starch content for fruiting bodies was highest on sawdust (5.31 g 100 g-1) and lowest on kenaf (2.66 g 100 g-1), while for mushroom substrates, kenaf was (0.33g 100 g-1) and palm fruit shaft was (4.45g 100 g-1). There was a positive correlation (r = 0.24) between the nutrient of fruiting bodies and that of the substrate on which it was cultivated.La production de la pleurote et produits d\ue9riv\ue9s fait de plus en plus objet de recherche dans le monde et surtout au Nigeria. La pr\ue9sente \ue9tude a \ue9t\ue9 r\ue9alis\ue9 afin de determiner la relation nutritionnelle entre le substrat de culture utilis\ue9 et type de champignon obtenu. Des d\ue9chets agricols comme le faux regime de palmier ( Elaeis guineensis ), les feuilles du banaier plantain ( Musa paradisiaca ), la sciure et tige de kenaf ( Hibiscus ), ont \ue9t\ue9 \ue9valu\ue9s pour leur aptitude \ue0 servir de substrats de culture pour la pleurote ( Pleurotus floridanus Singer ). Les spores du champignon ont \ue9t\ue9 utilis\ue9 pour inoculer chaque substrat. Les r\ue9sultats ont montr\ue9 que tous les substrats ont support\ue9 la croissance du mycelium et le d\ue9veloppement. Des differences significatives ont \ue9t\ue9 observ\ue9es entre les substrats (P<0.05), en ce qui concerne le nombre de jours n\ue9cessaires pour accomplir un cycle mycelien. Le cycle mycelien le plus court a \ue9t\ue9 observ\ue9 sur le faux r\ue9gime de palmier (25.20), tandis que le cycle le plus long \ue9tait observ\ue9 sur le kenaf (32.40). Les rendements totaux varient d\u2019un substrat \ue0 un autre (P<0.05); le meilleur rendement a \ue9t\ue9 obtenu sur faux r\ue9gime de palmier (51.4 g 100 g-1) et le plus faible rendement obtenu sur les feuilles du bananier plantain (6.0 g 100 g-1). Des differences significatives ont \ue9t\ue9 aussi observ\ue9es au niveau de la qualit\ue9 nutrionelle du champignon (P<0.05). Les champignons de meilleures qualit\ue9s nutritionnelles \ue9taient obtenus sur les feuilles de bananier plantain (1.72 g 100 g-1), tandis que les champignons \ue0 faible teneur en nutriments ont \ue9t\ue9 obtenus sur faux r\ue9gime de palmier (0.55 g 100 g-1). Le m\ueame constat a \ue9t\ue9 fait au niveau des substrats; les feuilles de bananiers plantain ayant (2.55 g 100 g-1) contre (0.41g 100 g-1) faux r\ue9gime de palmier. La teneur en amidon la plus \ue9lev\ue9e a \ue9t\ue9 obtenu sur la sciure (5.31 g 100 g-1), tandis que la plus faible teneur \ue9tait sur kenaf (2.66 g 100 g-1). En ce qui concerne la teneur en amidon des substrats, le kenaf exhibait (0.33g 100 g-1) et faux r\ue9gime de palmier a exhib\ue9 (4.45g 100 g-1). Une corr\ue9lation positive (r = 0.24) a \ue9t\ue9 observ\ue9e entre les nutriments au sein du champignon et ceux du substrat sur lequel il est cultiv\ue9

Temperature dependence of current self-oscillations and electric field domains in sequential tunneling doped superlattices

We examine how the current--voltage characteristics of a doped weakly coupled superlattice depends on temperature. The drift velocity of a discrete drift model of sequential tunneling in a doped GaAs/AlAs superlattice is calculated as a function of temperature. Numerical simulations and theoretical arguments show that increasing temperature favors the appearance of current self-oscillations at the expense of static electric field domain formation. Our findings agree with available experimental evidence.Comment: 7 pages, 5 figure

1D model of precursors to frictional stick-slip motion allowing for robust comparison with experiments

We study the dynamic behaviour of 1D spring-block models of friction when the external loading is applied from a side, and not on all blocks like in the classical Burridge-Knopoff-like models. Such a change in the loading yields specific difficulties, both from numerical and physical viewpoints. To address some of these difficulties and clarify the precise role of a series of model parameters, we start with the minimalistic model by Maegawa et al. (Tribol. Lett. 38, 313, 2010) which was proposed to reproduce their experiments about precursors to frictional sliding in the stick-slip regime. By successively adding (i) an internal viscosity, (ii) an interfacial stiffness and (iii) an initial tangential force distribution at the interface, we manage to (i) avoid the model's unphysical stress fluctuations, (ii) avoid its unphysical dependence on the spatial resolution and (iii) improve its agreement with the experimental results, respectively. Based on the behaviour of this improved 1D model, we develop an analytical prediction for the length of precursors as a function of the applied tangential load. We also discuss the relationship between the microscopic and macroscopic friction coefficients in the model.Comment: 13 pages, 14 figures, accepted in Tribology Letter

Spreading Dynamics of Polymer Nanodroplets

The spreading of polymer droplets is studied using molecular dynamics simulations. To study the dynamics of both the precursor foot and the bulk droplet, large drops of ~200,000 monomers are simulated using a bead-spring model for polymers of chain length 10, 20, and 40 monomers per chain. We compare spreading on flat and atomistic surfaces, chain length effects, and different applications of the Langevin and dissipative particle dynamics thermostats. We find diffusive behavior for the precursor foot and good agreement with the molecular kinetic model of droplet spreading using both flat and atomistic surfaces. Despite the large system size and long simulation time relative to previous simulations, we find no evidence of hydrodynamic behavior in the spreading droplet.Comment: Physical Review E 11 pages 10 figure

Are we SHARP enough? The importance of adequate patient selection in sorafenib treatment for hepatocellular carcinoma

Background: Upon FDA/EMEA registration for hepatocellular carcinoma (HCC), sorafenib received a broader therapeutic indication than the eligibility criteria of the landmark SHARP trial. This allowed treatment of SHARP non-eligible patients in daily clinical practice. Aim: To assess sorafenib efficacy and safety in SHARP eligible and non-eligible patients, and determine the validity of the current therapeutic indication as described by the FDA/EMEA. Patients and methods: Consecutive patients treated with sorafenib for advanced HCC at two Dutch tertiary referral centers between 2007 and 2016 were analyzed retrospectively. Primary outcome was overall survival (OS). Secondary outcomes were time to progression (TTP), response rate, adverse events and reasons for discontinuation. Outcomes were compared between SHARP eligible and non-eligible patients. Results: One hundred and ninety-three of 257 (75%) patients were SHARP eligible. SHARP eligible patient

Histidyl–tRNA Synthetase and Asparaginyl–tRNA Synthetase, Autoantigens in Myositis, Activate Chemokine Receptors on T Lymphocytes and Immature Dendritic Cells

Autoantibodies to histidyl–tRNA synthetase (HisRS) or to alanyl–, asparaginyl–, glycyl–, isoleucyl–, or threonyl–tRNA synthetase occur in ∼25% of patients with polymyositis or dermatomyositis. We tested the ability of several aminoacyl–tRNA synthetases to induce leukocyte migration. HisRS induced CD4+ and CD8+ lymphocytes, interleukin (IL)-2–activated monocytes, and immature dendritic cells (iDCs) to migrate, but not neutrophils, mature DCs, or unstimulated monocytes. An NH2-terminal domain, 1–48 HisRS, was chemotactic for lymphocytes and activated monocytes, whereas a deletion mutant, HisRS-M, was inactive. HisRS selectively activated CC chemokine receptor (CCR)5-transfected HEK-293 cells, inducing migration by interacting with extracellular domain three. Furthermore, monoclonal anti-CCR5 blocked HisRS-induced chemotaxis and conversely, HisRS blocked anti-CCR5 binding. Asparaginyl–tRNA synthetase induced migration of lymphocytes, activated monocytes, iDCs, and CCR3-transfected HEK-293 cells. Seryl–tRNA synthetase induced migration of CCR3-transfected cells but not iDCs. Nonautoantigenic aspartyl–tRNA and lysyl–tRNA synthetases were not chemotactic. Thus, autoantigenic aminoacyl–tRNA synthetases, perhaps liberated from damaged muscle cells, may perpetuate the development of myositis by recruiting mononuclear cells that induce innate and adaptive immune responses. Therefore, the selection of a self-molecule as a target for an autoantibody response may be a consequence of the proinflammatory properties of the molecule itself

Improved survival prediction and comparison of prognostic models for patients with hepatocellular carcinoma treated with sorafenib

Background: The ‘Prediction Of Survival in Advanced Sorafenib-treated HCC’ (PROSASH) model addressed the heterogeneous survival of patients with hepatocellular carcinoma (HCC) treated with sorafenib in clinical trials but requires validation in daily clinical practice. This study aimed to validate, compare and optimize this model for survival prediction. Methods: Patients treated with sorafenib for HCC at five tertiary European centres were retrospectively staged according to the PROSASH model. In addition, the optimized PROSASH-II model was developed using the data of four centres (training set) and tested in an independent dataset. These models for overall survival (OS) were then compared with existing prognostic models. Results: The PROSASH model was validated in 445 patients, showing clear differences between the four risk groups (OS 16.9-4.6 months). A total of 920 patients (n = 615 in training set, n = 305 in validation set) were available to develop PROSASH-II. This optimized model incorporated fewer and less subjective parameters: the serum albumin, bilirubin and alpha-foetoprotein, and macrovascul