Intestinal epithelial responses to Salmonella enterica serovar Enteritidis: Effects on intestinal permeability and ion transport

Salmonella infection of chickens that leads to potential human foodborne salmonellosis continues to be a major concern. Chickens serve as carriers but, in contrast to humans, rarely show any clinical signs including diarrhea. The present investigations aimed to elucidate whether the absence of diarrhea during acute Salmonella enterica serovar Enteritidis (Salmonella Enteritidis) infection may be linked to specific changes in the electrophysiological properties of the chicken gut. Immediately after slaughter, intestinal pieces of the mid-jejunum and cecum of either commercial broiler or specific pathogen-free (SPF) chickens were mounted in Ussing chambers in 2 separate experimental series. Living Salmonella Enteritidis (3 × 109) or Salmonella Enteritidis endotoxin (20 mg/L), or both, were added to the mucosal side for 1 h. In both experimental series, the Salmonella infection decreased the trans-epithelial ion conductance Gt (P < 0.05). In the jejunum of SPF chickens, there was also a marked decrease in net charge transfer across the epithelium, evidenced by decreased short-circuit current (Isc, P < 0.05). Interestingly, the mucosal application of Salmonella endotoxin to the epithelial preparations from jejunum and cecum of SPF chicken had an effect similar to living bacteria. However, the endotoxin had no additional effect on the intestinal function in the presence of bacteria. The decreasing effect of Salmonella and or its endotoxin on Gt could be partly reversed by serosal addition of histamine. To our knowledge, this is the first study to address the functional response of native intestinal epithelium of chicken to an in vitro Salmonella infection. For the first time, it can be reported that intestinal ion permeability of chicken decreases acutely by the presence of Salmonella. This type of response could counteract ion and fluid secretion and may thus, at least in part, explain why chickens do not develop overt diarrhea after Salmonella infection

Campylobacter jejuni colonization promotes the translocation of Escherichia coli to extra-intestinal organs and disturbs the short-chain fatty acids profiles in the chicken gut

For a long time Campylobacter was only considered as a commensal microorganism in avian hosts restricted to the ceca, without any pathogenic features. The precise reasons for the symptomless chicken carriers are still unknown, but investigations of the gastrointestinal ecology of broiler chickens may improve our understanding of the microbial interactions with the host. Therefore, the current studies were conducted to investigate the effects of Campylobacter jejuni colonization on Escherichia coli translocation and on the metabolic end products (short-chain fatty acids, SCFAs). Following oral infection of 14 day old broiler chickens with 1 × 108 CFU of Campylobacter jejuni NCTC 12744 in two independent animal trials, it was found that C. jejuni heavily colonized the intestine and disseminate to extra-intestinal organs. Moreover, in both animal trials, the findings revealed that C. jejuni promoted the translocation of E. coli with a higher number encountered in the spleen and liver at 14 days post infection (dpi). In addition, Campylobacter affected the microbial fermentation in the gastrointestinal tract of broilers by reducing the amount of propionate, isovalerate, and isobutyrate in the cecal digesta of the infected birds at 2 dpi and, at 7 and 14 dpi, butyrate, isobutyrate, and isovalerate were also decreased. However, in the jejunum, the C. jejuni infection lowered only butyrate concentrations at 14 dpi. These data indicated that C. jejuni may utilize SCFAs as carbon sources to promote its colonization in the chicken gut, suggesting that Campylobacter cannot only alter gut colonization dynamics but might also influence physiological processes due to altered microbial metabolite profiles. Finally, the results demonstrated that C. jejuni can cross the intestinal epithelial barrier and facilitates the translocation of Campylobacter itself as well as of other enteric microorganisms such as E. coli to extra-intestinal organs of infected birds. Altogether, our findings suggest that the Campylobacter carrier state in chicken is characterised by multiple changes in the intestinal barrier function, which supports multiplication and survival within the host

Investigation of nanodispersion in polystyrene-montmorillonite nanocomposites by solid state NMR

Nanocomposites result from combinations of materials with vastly different properties in the nanometer scale. These materials exhibit many unique properties such as improved thermal stability, reduced flammability, and improved mechanical properties. Many of the properties associated with polymer–clay nanocomposites are a function of the extent of exfoliation of the individual clay sheets or the quality of the nanodispersion. This work demonstrates that solid-state NMR can be used to characterize, quantitatively, the nanodispersion of variously modified montmorillonite (MMT) clays in polystyrene (PS) matrices. The direct influence of the paramagnetic Fe3, embedded in the aluminosilicate layers of MMT, on polymer protons within about 1 nm from the clay surfaces creates relaxation sources, which, via spin diffusion, significantly shorten the overall proton longitudinal relaxation time (T1 H). Deoxygenated samples were used to avoid the particularly strong contribution to the T1 H of PS from paramagnetic molecular oxygen. We used T1 H as an indicator of the nanodispersion of the clay in PS. This approach correlated reasonably well with X-ray diffraction and transmission electron microscopy (TEM) data. A model for interpreting the saturation-recovery data is proposed such that two parameters relating to the dispersion can be extracted. The first parameter, f, is the fraction of the potentially available clay surface that has been transformed into polymer–clay interfaces. The second parameter is a relative measure of the homogeneity of the dispersion of these actual polymer–clay interfaces. Finally, a quick assay of T1 H is reported for samples equilibrated with atmospheric oxygen. Included are these samples as well as 28 PS/MMT nanocomposite samples prepared by extrusion. These measurements are related to the development of highthroughput characterization techniques. This approach gives qualitative indications about dispersion; however, the more time-consuming analysis, of a few deoxygenated samples from this latter set, offers significantly greater insight into the clay dispersion. A second, probably superior, rapid-analysis method, applicable to oxygen-containing samples, is also demonstrated that should yield a reasonable estimate of the f parameter. Thus, for PS/MMT nanocomposites, one has the choice of a less complete NMR assay of dispersion that is significantly faster than TEM analysis, versus a slower and more complete NMR analysis with sample times comparable to TEM, information rivaling that of TEM, and a substantial advantage that this is a bulk characterization method. © 2003 Wiley Periodicals, Inc.* J Polym Sci Part B: Polym Phys 41: 3188–3213, 200

UTILIZATION OF FOUR SUDANESE WILD FRUITS TO PRODUCE NECTARS

Doum (Hyphaene thebaica L), kirkir (Randia geipaeflora), karmadoda (Naucleae latifolia) and godeim (Grewia tenax) are some of the indigenous fruits in Sudan. The aim of this investigation is to process nectars from the edible part of these fruits. Doum and kirkir fruits were soaked in water in variable ratios for different durations of time to obtain the highest total soluble solids, total solids and total extractable matter. The pulps of karmadoda and godeim fruits were obtained mechanically by adding water, blanching and pulping with pulper machine. Results showed that soaking of doum and kirkir fruits at ratios 1: 4/2 h and 1: 4/8 h, respectively, were the most appropriate methods for extraction. The total solids (TS) obtained were 10.61 and 10.32 %, total soluble solids (TSS) 10.50 and 9.50%, and the total extractable matters (TEM) were 26.06 and 23.69%, respectively. However, blanching karmadoda fruit in water at a ratio of 1: 2/10 min gave total solids of 5.63% and total soluble solids of 5.00%. The nectars made were subjected to organoleptic evaluation. The results suggested that processing of nectars from forest fruits by direct extraction gave excellent sensory characteristics for human consumption

The non-Abelian gauge theory of matrix big bangs

We study at the classical and quantum mechanical level the time-dependent Yang-Mills theory that one obtains via the generalisation of discrete light-cone quantisation to singular homogeneous plane waves. The non-Abelian nature of this theory is known to be important for physics near the singularity, at least as far as the number of degrees of freedom is concerned. We will show that the quartic interaction is always subleading as one approaches the singularity and that close enough to t=0 the evolution is driven by the diverging tachyonic mass term. The evolution towards asymptotically flat space-time also reveals some surprising features.Comment: 29 pages, 8 eps figures, v2: minor changes, references added: v3 small typographical changes

Scale without Conformal Invariance at Three Loops

We carry out a three-loop computation that establishes the existence of scale without conformal invariance in dimensional regularization with the MS scheme in d=4-epsilon spacetime dimensions. We also comment on the effects of scheme changes in theories with many couplings, as well as in theories that live on non-conformal scale-invariant renormalization group trajectories. Stability properties of such trajectories are analyzed, revealing both attractive and repulsive directions in a specific example. We explain how our results are in accord with those of Jack & Osborn on a c-theorem in d=4 (and d=4-epsilon) dimensions. Finally, we point out that limit cycles with turning points are unlike limit cycles with continuous scale invariance.Comment: 21 pages, 3 figures, Erratum adde

COATING OF GUAVA (PSIDIUM GUAJAVA L.) FRUITS WITH BOTANICAL EDIBLE OILS FOR SHELF LIFE AND FRUIT FLIES

Guava (Psidium guajava L.) fruit is a popular nutritious dessert in Sudan. It is famous for its medicinal values as a prompt cure for digestive disorders and respiratory ailness this besides being a rich source of C vitamin. This fruit is highly amenable to fruit fly attack and it is a harbor of eggs of five different species [Ceratitis capitata Wied.; Ceratitis quinaria Bez.; Ceratitis cosyra Wlk.; Bactrocera invadens De Trusta and White and Bactrocera zonata (Saunders)] in Sudan. This is stimulating to a chain of endless research to combat these notorious pests which account for huge losses in this crop that reach up to 80% or even more. This research aimed at evaluating the effect of oil coating on fruit fly infestation and the quality indexes in guava fruit using five different botanical edible oils. The results showed that groundnut (Arachis hypogaea L.) (GNO), sesame (Sesamum indicum L.) (SO), baobab (Adansonia digitata L.) (BO), olive (Olea europaea L.) (OO) and neem (Azadirachta indica A. Juss) (NO) oils effected a corrected disinfestation of 80, 72, 56, 52 and 28% in test fruits brought from Kadaro orchards North Khartoum, respectively. The corresponding average readings of maggots in infested fruits were 4, 17, 11, 5, 7 and [10 (for the first 4) and 26 for NO] in the control. Two essential quality indexes were checked in test fruits which included fruit color (FC) and firmness (FF). The corrected test readings reflected 64, 80, 44, 52,-4 and [8 (for the first 4) and 20 for NO] in the control sustained FC for GNO, SO, BO, OO, NO and the control, respectively. However, the corresponding readings for FF were 3 (medium) for all oils and 4 (soft) for the controls. These results reflect a potent and the best efficacy of peanut and sesame oils, of the five test oils, in controlling fruit flies in guava and extending its shelf life