Ethyl carbamate formation regulated by ornithine transcarbamylase and urea metabolism in the processing of Chinese yellow rice wine

Ethyl carbamate (EC) is a potential carcinogenic compound present in most of the fermented foods. In this work, EC was inhibited through different strategies during vinification of Chinese yellow rice wine. EC can be inhibited by the use of ornithine in contrast to the control at peak point. However, the utilisation of urease resulted in little inhibitive effect on EC. The comparative data of intracellular ornithine transcarbamylase (OTCase) and arginine deiminase (ADI) among four experiments showed that EC was positively regulated by intracellular OTCase, but ADI was not determined. Extracellular urea and citrulline content was significantly increased by adding ornithine (P < 0.05), whereas ethanol played a minor role in EC formation. The correlation analysis between EC and OTCase or urea revealed a linear association (correlation coefficients above 0.8). These findings suggested that OTCase may be a required factor regulating EC formation during the brewing of Chinese yellow rice wine.     

A Systems Level Approach for Identification of Molecular Targets for Antimicrobial Intervention against Pseudomonas Aeruginosa,while Predicting Biofilm Formation

In this case study, we aimed at evaluating the suitability of genome-scale metabolic models to identify molecular targets that can potentially enhance antimicrobial effects of chemical preservatives against P. aeruginosa, while minimizing biofilm formation. For the case study, isothiazolinones were selected as a group of microbicides where their mechanism of action is well described in scientific literature. Target identification was carried out in several steps. First, we developed a computational model of P. aeruginosa metabolism under action of isothiazolinones. Action of sub-inhibitory concentrations of isothiazolinones was simulated based on extensive information on their mechanisms of action. Then, simulations of single and double gene deletion(s) were performed in silico to identify genes or combinations of genes that could be targeted to induce further reduction of bacterial growth rate. Finally, we assessed whether total or partial inhibition of these genes might activate biofilm formation.     

Psychometric procedures and the detection and exploration of behavioural deficits due to cerebral dysfunction in man: II.

There are basically two approaches to the use of psychometric tests in the detection of "brain damage": the first is centred around a view of regional equipotentiality of brain functioning and the second around a unitary view of brain functioning. The former was explored in an earlier paper in this journal (Rubino, 1970). The latter approach is explored here in terms of the utility of three well-known tests: the Bender Gestalt, the Benton Visual Retention Test, and the Graham Kendall Memory for Designs. The influence of such factors as age, diagnoses, hit-rates, etc., are briefly discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Metabolic and biochemical responses of probiotic bacteria to oxygen

The interaction between oxygen and probiotic bacteria was studied by growing Lactobacillus acidophilus and Bifidobacterium spp. in 0, 5, 10, 15, and 21% oxygen in a hypoxic glove box. The metabolic responses of each probiotic strain in the different oxygen environments were monitored by measuring the levels of lactic acid and determining the lactate-to-acetate ratio. Biochemical changes induced by oxygen were examined by monitoring the specific activities of NADH oxidase, NADH peroxidase, and superoxide dismutase. In addition, the ability to decompose hydrogen peroxide and the sensitivity of each strain to hydrogen peroxide was also determined. With an increase in oxygen percentage, levels of lactic acid in L. acidophilus strains decreased, whereas the lactate-to-acetate ratio reduced in all the bifidobacteria tested. At 21% oxygen, the specific activities of NADH oxidase and NADH peroxidase, and the hydrogen peroxide decomposing ability of five probiotic strains was significantly higher than at 0% oxygen. The sensitivity of the probiotic strains to hydrogen peroxide however, remained unaffected in all the different oxygen percentages. Superoxide dismutase levels did not reveal any conclusive trend. In both L. acidophilus and Bifidobacterium spp., NADH oxidase and NADH peroxidase functioned optimally at pH 5. Growth in the various oxygen environments did not change this optimum pH.     

Concentrate feeding strategy in lactating dairy cows: metabolic and endocrine changes with emphasis on leptin

This study aimed to evaluate metabolic and endocrine adaptations to energy intake in multiparous Holstein cows (n = 90; mean 9434 kg energy-corrected milk yield/305 d) over the first 20 wk postpartum and to assess the association of leptin with metabolic, endocrine, and zootechnical traits. Concentrates were fed automatically for 24 h at 30% (C30) or 50% (C50) of total dry matter intake (DMI) from wk 1 to 10 postpartum and at linearly reduced amounts thereafter. Roughage was fed for ad libitum intake. The DMI was measured over 24 h; milk yield and body weight (BW), twice/d; milk composition, 4 times/wk; and milk acetone, weekly. Blood samples for determination of metabolite, hormone, and electrolyte concentrations and enzyme activities were obtained at wk 2 prepartum, and at wk 1 to 16 and at wk 20 postpartum from 0730 to 0900. Body condition scores (BCS) and backfat thickness were measured postpartum and during wk 1, 4, 8, 12, 16, and 20. Energy balance (EB) was considerably lower, but milk yield only slightly lower, in C30 than C50. Metabolic stress was more marked in C30 than C50, expressed by lower, glucose, insulin, insulin-like growth factor-1 (IGF-1), triiodothyronine, milk protein, and lactose concentrations, higher nonesterified fatty acid, beta-hydroxybutyrate, growth hormone, and milk acetone concentrations, and an accelerated decrease in BCS and backfat thickness. Nevertheless, C30 adapted successfully and thus maintained high milk yields despite negative EB. Leptin concentrations were lower in C30 than in C50 over the first 20 wk postpartum and were positively associated with BCS, EB, BW, cholesterol, albumin, insulin, and IGF-1; negatively associated with DMI and triiodothyronine; and were higher in cows calving in spring than in fall. Leptin is one among several factors involved in the regulation of energy metabolism and may be important for overall homeostatic and homeorhetic control of metabolism and thus for maintenance of performance.     

Biology by design: reduction and synthesis of cellular components and behaviour.

Biological research is experiencing an increasing focus on the application of knowledge rather than on its generation. Thanks to the increased understanding of cellular systems and technological advances, biologists are more frequently asking not only ‘how can I understand the structure and behaviour of this biological system?’, but also ‘how can I apply that knowledge to generate novel functions in different biological systems or in other contexts?’ Active pursuit of the latter has nurtured the emergence of synthetic biology. Here, we discuss the motivation behind, and foundational technologies enabling, the development of this nascent field. We examine some early successes and applications while highlighting the challenges involved. Finally, we consider future directions and mention non-scientific considerations that can influence the field''s growth.     

Role of T‐regulatory cells in the response to hepatitis B vaccine in hemodialysis patients

Human disease elicits a complex array of biological processes that results in long‐term protective immunological memory to infectious agents. Chronic kidney disease is known to impair induction of sustained immunological memory to hepatitis B vaccine (HBVax) antigens. We asked the question: Does end‐stage renal disease promote changes in subtypes of regulatory T (Treg) cells that correlate with diminished amnestic response to HBVax antigen compared to healthy controls? The study design and setting was a prospective observational cohort at a veterans affairs medical center. End‐stage renal disease patients on hemodialysis (HD) were compared with individuals with self‐reported normal kidney function. All subjects received HBVax. Peripheral blood was sampled for assessment for Treg cells pre and post vaccination. CD4+ FOXP3 Treg numbers were similar between HD and healthy subjects during a 14‐day time period post vaccination. HD subjcts had lower anti‐HBSag antibody than CON (control) subjects (330 ± 108.7 vs. 663.1 ± 129.7 IU/mL; P = 0.063). Hemodialysis subjects with resting Tregs higher than the median value in our cohort demonstrated a significantly lower change in HBsAB at 30 days post booster vaccination (P = 0.030). No such relationship was found for the activated Treg subset among HD subjects, or either subset among CON subsets. In our limited comparison study of 11 HD and 8 CON subjects, Treg subsets did not differ between the two groups; but differences in the suppressive Treg numbers in the HD group could explain the altered antibody response to HBVax and is worthy of further study.     

An algebraic formulation of inverse problems in MP dynamics

Metabolic P (MP) grammars are a particular class of multiset rewriting grammars introduced in the MP theory for modelling metabolic processes. In this paper, a new algebraic formulation of inverse problems, based on MP grammars and Kronecker product, is given, for further motivating the correctness of the LGSS (Log-Gain Stoichiometric Stepwise) algorithm, introduced in 2010s for solving inverse problems in the MP framework. At the end of the paper, a section is included that introduces the problem of multicollinearity, which could arise during the execution of LGSS, and that defines an algorithm, based on a hierarchical clustering technique, that solves it in a suitable way.