Comparative analysis of genetic structure of 2 species of marine fish Dicentrarchus labrax and Dicentrarchus punctatus

We present here the genetic structure existing among five samples of the spotted sea bass Dicentrarchus punctatus, and we compare it to what prevails in the common sea bass D. labrax, a congeneric species sampled on almost the same geographical range. A genetic distance tree inferred from the polymorphism at six microsatellite loci shows a distinct pattern for the two species. D. labrax samples appears to be genetically more homogeneous with a global Fst of 3% as compared to the 10% observed at D. punctatus, indicating a lesser level of gene flow in the latter species. While appearing more differentiated, D. punctatus presents no clear geographical organisation of its genetic variability in opposition to D. labrax samples. This allows us to propose this pair of closely relative species as a good candidate for the study by comparative analysis of the biological and/or historical factors affecting genetic differentiation in marine environment.     

Medical control of bioterrorism

Against the recently accrued risk of bioterrorism, the Biotox plan has been set up in order to take in charge any person that could be facing a potential terrorist contamination. It has to take into consideration the components of bioterrorism, i.e. the incubation period, the function of bacterial or viral agents, the variable number of concerned people, the difficulty of alert launching, and the diagnosis of the responsible agent. This plan relies on hospitals comprising departments of infectious diseases. Those are specifically in charge of informing, organising, and coordinating the reception of people having been in contact or infected by infectious agents, in order to isolate and treat them properly. The recent experience has allowed to test this plan, to precise and correct some of its features.     

Validation and use of an enzymic time-temperature integrator to monitor thermal impacts inside a solid/liquid model food

Heat denaturation kinetics of Bacillus licheniformis alpha-amylase, equilibrated at 81% equilibrium relative humidity at 4 degrees C (BLA81), was studied with help of isothermal and nonisothermal conditions by monitoring the decrease in enthalpy associated with the heat denaturation of the enzyme. Due to its low water content, BLA81 denaturation could be studied in the range of 118-124 degrees C. Two batches of BLA81 were successfully validated under nonisothermal conditions allowing the determinations of process values (reference temperature of 121.1 degrees C) in the range of 1-15 min. In a second step, BLA81 was used as a time-temperature integrator (TTI) to investigate potential differences of process values received by freely moving spherical particles as compared to a centrally fixed particle (single-position impact) inside cans containing water as brine. Results showed that the process value received by freely moving particles can be from 5.6% (4 rpm) to 19.7% (8 rpm) smaller than the process value received by the centrally fixed sphere. This means that evaluating the process value by means of a particle fixed at the critical point in a package can lead to potentially overestimations of the actual process value with possible hazardous quality/safety implications. These results highlight the potentials of the TTI technology to monitor the safety of heat-processed agitated solid/liquid foodstuffs.     

Purification and investigation of some kinetic properties of glucose-6-phosphate dehydrogenase from parsley (Petroselinum hortense) leaves

In this study, glucose-6-phosphate dehydrogenase (D-glucose-6-phosphate: NADP+ oxidoreductase, EC 1.1.1.49; G6PD) was purified from parsley (Petroselinum hortense) leaves, and analysis of the kinetic behavior and some properties of the enzyme were investigated. The purification consisted of three steps: preparation of homogenate, ammonium sulfate fractionation, and DEAE-Sephadex A50 ion exchange chromatography. The enzyme was obtained with a yield of 8.79% and had a specific activity of 2.146 U (mg protein)(-1). The overall purification was about 58-fold. Temperature of +4 degrees C was maintained during the purification process. Enzyme activity was spectrophotometrically measured according to the Beutler method, at 340 nm. In order to control the purification of enzyme, SDS-polyacrylamide gel electrophoresis was carried out in 4% and 10% acrylamide for stacking and running gel, respectively. SDS-polyacrylamide gel electrophoresis showed a single band for enzyme. The molecular weight was found to be 77.6 kDa by Sephadex G-150 gel filtration chromatography. A protein band corresponding to a molecular weight of 79.3 kDa was obtained on SDS-polyacrylamide gel electrophoresis. For the enzymes, the stable pH, optimum pH, and optimum temperature were found to be 6.0, 8.0, and 60 degrees C, respectively. Moreover, KM and Vmax values for NADP+ and G6-P at optimum pH and 25 degrees C were determined by means of Lineweaver-Burk graphs. Additionally, effects of streptomycin sulfate and tetracycline antibiotics were investigated for the enzyme activity of glucose-6-phosphate dehydrogenase in vitro.     

A simplified method for the detection of Y chromosome microdeletions in infertile men using a multiplex sequence-tagged site-based amplification

Sixteen sequence-tagged sites (STSs) were combined in five amplification reactions, to screen for deletions of DNA fragments located within the AZFa, AZFb, and AZFc regions of the Y chromosome. This multiplex strategy is fast and reliable, and most of the azoospermia-associated deletions reported so far are detected with this simplified method. Internal control STSs are included that allow discrimination between deletion and failure of amplification.     

Exploring human interaction and diet effects on the behavior of dogs in a public animal shelter

This study examined the effects of 2 manipulations-a brief, regular period of human contact and diet-on the behavior of dogs confined in a public animal shelter. A behavioral battery designed to assess reactions to novel situations, and a test of responsiveness to an unfamiliar human were administered both prior to (pretest) and immediately following (posttest) the 8-week intervention period. Overall, the regular periods of increased human contact together with a diet that contained augmented levels of digestible protein, fat, calories, and animal-derived ingredients reduced signs of behavioral reactivity from pretest to posttest. In some cases, the comparison diet appeared more effective, but only for dogs receiving minimal human interaction. The results indicate that a combination of human interaction and high quality diet may positively affect the behavior of dogs in animal shelters.     

Expression and evolution studies of ets genes in a primitive coelomate,the polychaete annelid,Hediste (Nereis) diversicolor

The Ets family includes numerous proteins with a highly conserved DNA-binding domain of 85 amino acids named the ETS domain. Phylogenetic analyses from ETS domains revealed that this family could be divided into 13 groups, among them are ETS and ERG. The ets genes are present in the Metazoan kingdom and we have previously characterized the Nd ets and Nd erg genes in the polychaete annelid Hediste diversicolor. Here, we isolated a fragment encoding the ETS domain from Nd Ets, by genomic library screening. By Northern blot analysis, we showed that this gene was transcribed as one major mRNA of 2.6 kb and one minor mRNA of 3.2 kb. By in situ hybridization, we observed that Nd ets was expressed in the intestine and oocytes and that Nd erg was expressed in cellular clumps present in the coelomic cavity, in an area of proliferating cells situated between the last metamere and the pygidium. Finally, we showed that Nd erg shared the expression pattern of Nd ets in oocytes. Molecular modeling studies have revealed that the spatial structure of ETS domain of Nd Ets and Nd Erg was conserved, in comparison to the murine Ets-1 and human Fli-1 proteins, respectively.     

Identification and antifungal susceptibility of Candida isolated from intensive care unit patients

Candida was isolated in 205 of 1060 clinical specimens (19.33%) in our laboratary sent from the intensive care unit for mycological investigation between January 98-December 99. All isolated strains were identified to species level using the API Candida system (Bio-Meieux, France) as follows; Candida albicans (n:115, 56.09%), Candida tropicalis (n:23, 11.21%), Candida parapsilosis (n:21, 10.24%), Candida glabrata (n:12, 5.83%). Candida kefyr (n:9, 4.39%), Candida lusitaniae (n:7, 3.41%), Candida famata (n:6, 2.92%), Candida krusei (n:6, 2.92%), Candida guilliermondii (n:6, 2.92%). These stains were identified using congo-red-glucose-brain-heart-infusion agar and slime production was determined in Candida albicans 53.91% and 67.77% in other than Candida species. In the present study, E test (AB Biodisk, Solna, Sweeden) was used to test antifungal susceptibility. The resistance to amphotericin B was 19.51%, to fluconazole 27.31% and to flucytosine 20.00%.     

Dose-effect of interleukin-10 and its immunoregulatory role in Crohn's disease

BACKGROUND: Interleukin-10 (IL-10) is currently being extensively studied in clinical trials for the treatment of Crohn's disease (CD). Only marginal effects have, however, been reported, and the dose-response curve was bell-shaped contrasting with the reported data from in vitro experiments. AIM: To use another in vitro model to analyze the effect of rhIL-10 and rhIL-4 on the spontaneous mucosal TNF-alpha secretion in patients with CD, and to characterize the phenotype of the cells targeted by rhIL-10. METHODS: Non-inflamed colon biopsies from CD patients were cultured for 16 hours in presence of different concentrations of rhIL-10 or rhIL-4. The numbers of TNF-alpha-secreting cells among isolated lamina propria mononuclear cells (LPMNC) were estimated by Elispot. RESULTS: Both rhIL-10 and rhIL-4 down-regulate TNF-alpha secretion by LPMNC from CD patients, with a more pronounced effect with rhIL-10. These effects were closely linked to the cytokine concentrations used, with a bell-shaped dose-response curve. Residual TNF-alpha secretion, in the presence of optimal rhIL-10 concentration was mainly attributable to CD3+ T cells. In contrast, at higher rhIL-10 concentrations, CD3- cells contributed significantly to the TNF-alpha secretion. CONCLUSIONS: The in vitro model we used, demonstrates that IL-4, but mostly IL-10, efficiently suppresses TNF-alpha secretion in LPMNC from CD patients, with a dose-response curve similar to results obtained in vivo. Resistance at high rhIL-10 concentrations was associated with a change in the phenotype of TNF-alpha-secreting cells.     

Why are complementary DNA strands symmetric?

MOTIVATION: Over sufficiently long windows, complementary strands of DNA tend to have the same base composition. A few reports have indicated that this first-order parity rule extends at higher orders to oligonucleotide composition, at least in some organisms or taxa. However, the scientific literature falls short of providing a comprehensive study of reverse-complement symmetry at multiple orders and across the kingdom of life. It also lacks a characterization of this symmetry and a convincing explanation or clarification of its origin. RESULTS: We develop methods to measure and characterize symmetry at multiple orders, and analyze a wide set of genomes, encompassing single- and double-stranded RNA and DNA viruses, bacteria, archae, mitochondria, and eukaryota. We quantify symmetry at orders 1 to 9 for contiguous sequences and pools of coding and non-coding upstream regions, compare the observed symmetry levels to those predicted by simple statistical models, and factor out the effect of lower-order distributions. We establish the universality and variability range of first-order strand symmetry, as well as of its higher-order extensions, and demonstrate the existence of genuine high-order symmetric constraints. We show that ubiquitous reverse-complement symmetry does not result from a single cause, such as point mutation or recombination, but rather emerges from the combined effects of a wide spectrum of mechanisms operating at multiple orders and length scales.