Colonization, persistence, and tissue tropism of Escherichia coli O26 in conventionally reared weaned lambs

Escherichia coli O26 is recognized as an emerging pathogen associated with disease in both ruminants and humans. Compared to those of E. coli O157:H7, the shedding pattern and location of E. coli O26 in the gastrointestinal tract (GIT) of ruminants are poorly understood. In the studies reported here, an stx-negative E. coli O26 strain of ovine origin was inoculated orally into 6-week-old lambs and the shedding pattern of the O26 strain was monitored by serial bacteriological examination of feces. The location of colonization in the GIT was examined at necropsy at two time points. The numbers of O26 organisms excreted in feces declined from approximately 10(7) to 10(4) CFU per gram of feces by day 7 and continued at this level for a further 3 weeks. Beyond day 30, excretion was from few animals, intermittent, and just above the detection limit. By day 38, all fecal samples were negative, but at necropsy, O26 organisms were recovered from the upper GIT, specifically the ileum. However, no attaching-effacing (AE) lesions were observed. To identify the location of E. coli O26 within the GIT early after inoculation, two lambs were examined postmortem, 4 days postinoculation. High numbers of O26 organisms were recovered from all GIT sites examined, and approximately 10(9) CFU were recovered from 1 gram of ileal tissue from one animal. Despite high numbers of O26 organisms, AE lesions were identified on the mucosa of the ascending colon of only one animal. These data indicate that E. coli O26 readily colonizes 6-week-old lambs, but the sparseness of AE lesions suggests that O26 is well adapted to this host, and mechanisms other than those dependent upon intimin may play a role in persistence.     

Evaluation of method performance for oxidative stress biomarkers in urine and biological variations in urine of patients with type 2 diabetes mellitus and diabetic nephropathy

Background

Oxidative stress biomarkers such as superoxide dismutase (CuZnSOD), catalase (CAT) and malondialdehyde (MDA) play an important role in the pathogenesis or progression of numerous diseases. Data regarding the biological variation and analytical quality specifications (imprecision, bias and total error) for judging the acceptability of method performance for oxidative stress biomarkers in urine are conspicuously lacking in the literature. Such data are important in setting analytical quality specifications, assessing the utility of population reference intervals (index of individuality) and assessing the significance of changes in serial results from an individual (reference change value; RCV).

Materials and methods

20 patients with type 2 diabetes mellitus (T2DM), 20 patients with diabetic nephropathy (DN) and 14 healthy individuals as control were involved in this study. Timed first morning urine samples were taken from patients and healthy groups on the zero, 1st, 3rd, 5th, 7th, 15th and 30th days. Index of individuality and reference change value were calculated from within-subject and between-subject variations. Methods of oxidative stress biomarkers in human blood were adopted in human urine and markers were measured as spectrophotometrically. Also, analytical quality specifications for evaluation of the method performance were established for oxidative stress biomarkers in urine.

Results

Within-subject variations of oxidative stress biomarkers were significantly higher in patients with DN and T2DM compared to healthy subjects. MDA showed low individuality, and within-subject variances of MDA were larger than between-subject variances in all groups. However, CAT and CuZnSOD showed strong individuality, but within-subject variances of them were smaller than between-subject variances in all groups. RCVs of all analytes in diabetic patients were relatively higher, because of high within-subject variation, resulting in a higher RCV. Also, the described methodology achieves these goals, with analytical CVs of < 3.5% for all analytes. Goals for bias and total error were 6.0-7.9% and 12.5-23.3%, respectively.

Conclusions

RCVs concept for predicting the clinical status in diabetic patients represents an optimization of laboratory reporting and could be a valuable tool for clinical decision. Furthermore, for oxidative stress biomarkers’ measurements in urine, the desirable imprecision goals based on biological variation are obtainable by current methodologies.     

Optimization of NMR spectroscopy of encapsulated proteins dissolved in low viscosity fluids

Comprehensive application of solution NMR spectroscopy to studies of macromolecules remains fundamentally limited by the molecular rotational correlation time. For proteins, molecules larger than 30 kDa require complex experimental methods, such as TROSY in conjunction with isotopic labeling schemes that are often expensive and generally reduce the potential information available. We have developed the reverse micelle encapsulation strategy as an alternative approach. Encapsulation of proteins within the protective nano-scale water pool of a reverse micelle dissolved in ultra-low viscosity nonpolar solvents overcomes the slow tumbling problem presented by large proteins. Here, we characterize the contributions from the various components of the protein-containing reverse micelle system to the rotational correlation time of the encapsulated protein. Importantly, we demonstrate that the protein encapsulated in the reverse micelle maintains a hydration shell comparable in size to that seen in bulk solution. Using moderate pressures, encapsulation in ultra-low viscosity propane or ethane can be used to magnify this advantage. We show that encapsulation in liquid ethane can be used to reduce the tumbling time of the 43 kDa maltose binding protein from ~23 to ~10 ns. These conditions enable, for example, acquisition of TOCSY-type data resolved on the adjacent amide NH for the 43 kDa encapsulated maltose binding protein dissolved in liquid ethane, which is typically impossible for proteins of such size without use of extensive deuteration or the TROSY effect.     

Rheological Behaviour of Instant Hot Chocolate Beverage: Part 1. Optimization of the Effect of Different Starches and Gums

In this study, effects of different starches (tapioca (TS), wheat (WS), corn (CS), potato (PS), modified corn (MCS) and modified potato (MPS)) and gums (xanthan gum (XG), guar gum (GG), alginate (A), salep (S), locust bean gum (LBG) and carrageen (C)) on the rheological properties of model hot chocolate beverage were studied. Swelling power (SP) of the starches and water absorption capacity (WAC) of the gums were determined. Hot chocolate beverages showed pseudoplastic behaviour. Ostwald de Waele model accurately described flow behaviour of each beverage sample. K, n, R ² values for Ostwald model were in the range of 4.8–160.3 mPa.sⁿ, 0.5117–0.9745, 0.9972–0.9998, respectively. The highest synergic effect in the model was observed between the interaction of MCS and XG. The XG-PS, XG-TS, XG-CS combinations showed the highest K and viscosity values, respectively.     

Immunoglobulin-G and creatinine levels in rabbits in altitude adaptation.

The changes of immunoglobulin-G and creatinine levels in mid-altitude were investigated in rabbits. The animals living at sea level were exposed to 2240 m altitude for 22 days period. When compared with sea level values; immunoglobulin-G levels were significantly low. Serum creatinine level decreased significantly in the 2nd day, then reached the sea level amount on the 12th day. On the 22nd day a significant increase was observed. It was concluded that the decrease in immunoglobulin-G values may be due to the depression of protein synthesis. The increase in plasma creatinine level would be explained by the decrease in urine.     

Pyrolysis of grape bagasse: effect of pyrolysis conditions on the product yields and characterization of the liquid product

In this study, pyrolysis of grape bagasse was investigated with the aim to study the product distribution and their chemical compositions and to identify optimum process conditions for maximizing the bio-oil yield. Particular investigated process variables were temperature (350-600 °C), heating rate (10-50 °C/min) and nitrogen gas flow rate (50-200 cm³/min). The maximum oil yield of 27.60% was obtained at the final pyrolysis temperature of 550 °C, sweeping gas flow rate of 100 cm³/min and heating rate of 50 °C/min in a fixed-bed reactor. The elemental analysis and heating value of the bio-oils were determined, and then the chemical composition of the bio-oil was investigated using chromatographic and spectroscopic techniques such as column chromatography, ¹H NMR and FTIR. The fuel properties of the bio-oil such as flash point, viscosity and density were also determined. The bio-oils obtained from grape bagasse were presented as an environmentally friendly feedstock candidate for bio-fuels.     

Induction of secretory aspartyl proteinase of <Emphasis Type="Italic">Candida albicans </Emphasis>by HIV-1 but not HSV-2 or some other microorganisms associated with vaginal environment

The most common type of candidiasis involves mucosal sites such as the oral cavity, the gastrointestinal tract and the vagina. Among many of virulence factors, the production of secretory aspartyl proteinase (Sap) by Candida albicans (C. albicans) has gained much attention, and factors leading to Sap induction are thus under intense study. The aim of this study was to examine whether some microorganisms such as Lactobacillus, Gardnerella vaginalis (G. vaginalis), human immunodeficiency virus type-1 (HIV-1) and human herpes simplex virus type-2 (HSV-2) had any Sap inducing effect on C. albicans. Here we showed that among the microorganisms tested in vitro only HIV-1 induced Sap production from C. albicans.