Polymicrobial interactions influence the agr copy number in Staphylococcus aureus isolates from diabetic foot ulcers.

Diabetic foot ulcers are a major complication of diabetes and are often colonised by complex bacterial communities, where Staphylococcus aureus is frequently co-present with Pseudomonas aeruginosa. These bacteria interact through quorum sensing, encoded in S. aureus by the accessory gene regulator (agr). Typing and copy number of S. aureus agr were assessed here to give insights on strain variability and possible interspecies influence. As agr is classified in four genetic groups, agr-I, agr-II, agr-III and agr-IV, the agr type of 23 S. aureus diabetic foot ulcers isolates was evaluated by PCR and gene copy number determined by qPCR, including in S. aureus present in polymicrobial infections. agr-I and agr-II were found to be present in 52 and 39% of the isolates, respectively. In two isolates, no agr type was identified, and types III and IV were not detected. Interestingly, agr-II copy number was higher in dual suspensions than in S. aureus single suspension. We conclude that agr type I was the most frequent in clinical centers in Lisbon, and variations in agr-I and agr-II copy numbers were strain specific. Variations in agr copy number in dual suspensions suggests that P. aeruginosa may influence S. aureus agr-II gene regulation, confirming an interaction between these two bacteria. This is a first approach to characterise agr variation in S. aureus from diabetic foot ulcers in vitro.

Fecal contamination of wastewater treatment plants in Portugal.

Reutilization of effluents from wastewater treatment plants (WWTP) for non-potable applications is increasing due to the reduction of sustainable water resources. These products mostly come from municipal WWTP and also from slaughterhouses effluents. The microbiological certification of these products is mandatory before their discharge into the environment. This study evaluates if the treatment applied in WWTP to municipal waters or to poultry slaughterhouse effluents distributed over the Portuguese continental territory is efficient in reducing the microbiological risk associated with the reutilization of those wastewaters and sludges. Fecal indicators Escherichia coli and enterococci were evaluated in 42 and 24 wastewater samples from 14 municipal WWTP and 8 poultry slaughterhouse treatment plants, respectively, by the conventional culture method and a rapid Fluorescent in situ hybridization (FISH) technique. Bacterial enumeration in inflow water from most WWTP was rather high (generally >10(5) cells/ml), for both E. coli and Enterococcus spp., and the bacterial quantification by FISH was generally higher than enumeration by the conventional culture method. In both types of treatment plants studied, bacterial load from effluents and sludges was not statistically different from the inflows, indicating that the treatment applied seems to be equally unable to reduce the microbiological load of the effluents. These findings may jeopardize the safe reuse of treated wastewaters in agriculture and the quality of the water environment. Therefore, products like water, sewage sludge, and biosolids originated from the municipal and slaughterhouse WWTP studied should not be reutilized, and effluents treatment should be urgently reviewed.

The Effect of Weight Loss on the Muscle Proteome in the Damara, Dorper and Australian Merino Ovine Breeds.

Seasonal Weight Loss (SWL) is an important constraint, limiting animal production in the Tropics and the Mediterranean. As a result, the study of physiological and biochemical mechanisms by which domestic animal breeds respond to SWL is important to those interested in animal breeding and the improvement thereof. To that end, the study of the proteome has been instrumental in gathering important information on physiological mechanisms, including those underlying SWL. In spite of that, little information is available concerning physiological mechanisms of SWL in production animals. The objective of this study was to determine differential protein expression in the muscle of three different breeds of sheep, the Australian Merino, the Dorper and the Damara, each showing different levels of tolerance to weight loss (low, medium and high, respectively). Per breed, two experimental groups were established, one labeled "Growth" and the other labeled "Restricted." After forty-two days of dietary treatment, all animals were euthanized. Muscle samples were then taken. Total protein was extracted from the muscle, then quantified and two-dimensional gel electrophoresis were conducted using 24 cm pH 3-10 immobiline dry strips and colloidal coomassie staining. Gels were analyzed using Samespots® software and spots of interest were in-gel digested with trypsin. The isolated proteins were identified using MALDI-TOF/TOF. Results indicated relevant differences between breeds; several proteins are suggested as putative biomarkers of tolerance to weight loss: Desmin, Troponin T, Phosphoglucomutase and the Histidine Triad nucleotide-binding protein 1. This information is of relevance to and of possible use in selection programs aiming towards ruminant animal production in regions prone to droughts and weight loss.

Fatty acid composition of the ovine longissimus dorsi muscle: effect of feed restriction in three breeds of different origin.

BACKGROUND: Muscle fatty acid profile reflects the body condition of animals and has a noticeable effect on meat quality. Herein, longissimus dorsi muscle of three different sheep breeds, Damara (a fat-tailed breed), Dorper and Australian Merino sheep, was analysed for fatty acid composition. The three breeds were subjected to two distinctive feeding levels (ad libitum and restricted feeding) over 42 days. RESULTS: The Damara sheep revealed several differences compared to the other two breeds, namely a higher concentration of polyunsaturated fatty acids, which can be related to being a fat-tailed breed. Even in restricted feeding conditions, this breed revealed the highest levels compared to Merino and Dorper sheep respectively, of linoleic acid (+31% and +28%), linolenic acid (+97% and +51%), eicosapentaenoic acid (EPA) (+65% and +37%), docosapentanenoic acid (DPA) (+31% Merino) and dodosahexanenoic acid (DHA) (+63% and +77%). EPA, DPA and DHA are three omega-3 fatty acids, with described beneficial characteristics. CONCLUSION: With this work we show other qualities (higher levels of the omega-3 fatty acids, EPA, DPA and DHA) of Damara meat that might present this breed as an interesting alternative for animal production in semi-arid climates.

Establishment of a proteomic reference map for the gastrocnemius muscle in the rabbit (Oryctolagus cuniculus).

In several laboratory and production species, the establishment of a proteome reference map of a specific tissue has been accomplished. The rabbit is widely used as both a production and experimental animal. A lot of physiology research involving the gastrocnemius muscle of rabbit is described, although no reference proteome map is available. In this work, the first reference map of the rabbit's gastrocnemius muscle using 2D gel electrophoresis and the identification of proteins through peptide mass fingerprinting (PMF) was established. A total of 45 proteins were localized and identified with three major roles: cell structure and contractile apparatus; metabolic and cell defense proteins. A reference map of major proteins expressed is described enabling possible comparisons with other physiological studies.