Targeting of Regulators as a Promising Approach in the Search for Novel Antimicrobial Agents

Since the discovery of penicillin in the first half of the last century, antibiotics have become the pillars of modern medicine for fighting bacterial infections. However, pathogens resistant to antibiotic treatment have increased in recent decades, and efforts to discover new antibiotics have decreased. As a result, it is becoming increasingly difficult to treat bacterial infections successfully, and we look forward to more significant efforts from both governments and the scientific community to research new antibacterial drugs. This perspective article highlights the high potential of bacterial transcriptional and posttranscriptional regulators as targets for developing new drugs. We highlight some recent advances in the search for new compounds that inhibit their biological activity and, as such, appear very promising for treating bacterial infections

Largemouth bass (Micropterus salmoides Lacépède): results of farming trials

In the last years in the United States, the demand of largemouth bass (Micropterus salmoides) larger than the size usually produced for sport fishing purposes has increased. The growth phase is carried on in ponds, after having evaluated different strains (Williamson and Carmichael, 1990) using feeds for salmonids (Tidwell et al., 1996) supplemented with amino acids (Coyle et al., 2000). Also in Italy, the market currently requires largemouth bass of 300-500 g. This situation has induced one farmer to cooperate with our research centre and carried out trials to verify the possibility of rearing this fish, from the fingerling stage up to the size suitable for food, using the same farming techniques as those currently being applied in the United States (Davis and Lock, 1997)

Feeling the heat: The campylobacter jejuni HrcA transcriptional repressor is an intrinsic protein thermosensor

The heat-shock response, a universal protective mechanism consisting of a transcriptional reprogramming of the cellular transcriptome, results in the accumulation of proteins which coun-teract the deleterious effects of heat-stress on cellular polypeptides. To quickly respond to thermal stress and trigger the heat-shock response, bacteria rely on different mechanisms to detect temperature variations, which can involve nearly all classes of biological molecules. In Campylobacter jejuni the response to heat-shock is transcriptionally controlled by a regulatory circuit involving two re-pressors, HspR and HrcA. In the present work we show that the heat-shock repressor HrcA acts as an intrinsic protein thermometer. We report that a temperature upshift up to 42°C negatively affects HrcA DNA-binding activity to a target promoter, a condition required for de-repression of regu-lated genes. Furthermore, we show that this impairment of HrcA binding at 42°C is irreversible in vitro, as DNA-binding was still not restored by reversing the incubation temperature to 37°C. On the other hand, we demonstrate that the DNA-binding activity of HspR, which controls, in combi-nation with HrcA, the transcription of chaperones’ genes, is unaffected by heat-stress up to 45°C, portraying this master repressor as a rather stable protein. Additionally, we show that HrcA binding activity is enhanced by the chaperonin GroE, upon direct protein–protein interaction. In conclu-sion, the results presented in this work establish HrcA as a novel example of intrinsic heat-sensing transcriptional regulator, whose DNA-binding activity is positively modulated by the GroE chap-eronin

Correction to: Quality traits of raw and cooked cupped oysters

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Evaluation of reproductive performances of the common octopus (Octopus vulgaris) reared in water recirculation systems and fed different diets

The reproductive performance of Octopus vulgaris broodstocks fed two different diets (mixed fish [F group, BW 1,048.14 g] or mixed crustaceans [C group, BW 998.44 g]) was analyzed using an experimental recirculating aquaculture system consisting of a tank equipped with spawning and incubation chambers. A total of 8 females (F1–4; C1–4), and 8 males (M1–M8) were selected. DI of the C group females was significantly (p < 0.05) higher (3.0 ± 0.29%) than the F group (2.16 ± 0.67%). SGR in C group was significantly higher (1.43 ± 0.12%) than the F group (1.18 ± 0.25%). Egg clusters, number of clusters, number of clusters/kg BW, and total length were more favorable in the C group than the F group. The number of clusters/kg BW of C females was 2.5 times higher than that of F females (78.1 ± 6.5 vs 31.1 ± 13.3). The total eggs number, number of eggs/cm, number of eggs/kg BW in the C group were significantly (p < 0.05) higher compared with the F group; the number of eggs/kg BW and paralarvae/kg BW were 5 times higher in the C group (115,928 ± 12,513 C vs 22,109 ± 7912 F and 114,953 ± 12,591 vs 20,729 ± 7104, respectively). Hatching rate of the C group was significantly (p < 0.05) higher compared to the F grou

Modulation of morphology and glycan composition of mucins in farmed guinea fowl (Numida meleagris) intestine by the multi-strain probiotic slab51®

Probiotics have become highly recognized as supplements for poultry.Since gut health can be considered synonymous withanimal health, the effects of probiotic Slab51® on the morphology and the glycan composition of guineafowlintestine were examined. The probiotics were added in drinking water (2 × 1011 UFC/L) throughout the grow-out cycle.Birds were individually weighed andslaughtered after four months. Samples from the duodenum, ileum and caecum were collected and processed for morphological, morphometric, conventional and lectin glycohisto-chemical studies.The results were analyzed for statistical significance by Student’s t test. Compared with control samples, probiotic group revealed (1) significant increase in villus height (p < 0.001 in duodenum and ileum; p < 0.05 in caecum), crypt depth (p < 0.001 in duodenum and caecum;p < 0.05 in ileum) and goblet cells (GCs) per villus (p < 0.001) in all investigated tracts; (2) increase in galac-toseβl,3N-acetylgalacyosamine(Galβl,3GalNAc)terminating O-glycans and αl,2-fucosylated glycans secretory GCs in the duodenum; (3) increase in α2,6-sialoglycans and high-mannose N-linked glycans secretory GCs but reduction in GCs-secreting sulfoglycans in the ileum; (4) increase in Galβl,3GalNAc and high-mannose N-linked glycans secretory GCs and decrease in GCs-producing sulfomucins in the caecum; (5) increase in the numbers of crypt cells containing sulfate and non-sulfated acidic glycans. Overall, dietary Slab51® induces morphological and region-specific changes in glycoprotein composition of guinea fowl intestine, promoting gut health

Effects of dietary supplementation with krill meal on pigmentation and quality of flesh of rainbow trout (Oncorhynchus mykiss)

Effects of administration of krill meal and synthetic astaxanthin during the finisher phase of the fattening cycle of rainbow trout on flesh pigmentation and quality traits were studied. The inclusion of krill meal increased the body weight and size and decreased the peri-visceral fat and visceral weight indices. The astaxanthin diet produced the highest accumulation of total carotenoids in the fillet compared to the krill meal diet: the difference was significant after 15 days of feeding (2.50 vs 2.10 mg/kg) till the end of the trial (5.00 vs 4.80 mg/kg). The same pattern was observed for astaxanthin concentration with the highest values in the fillets of fish fed the astaxanthin diet. Fillet lightness (L*) was not affected by trout diets whereas redness (a*) and yellowness (b*) were significantly higher in fish fed the astaxanthin diet until day 30 of the trial. Hue was not affected by feeding, whereas chroma was significantly higher in the fish fed astaxanthin throughout the trial except on day 45 of sampling. Trout fed the krill meal diet had a paler pink-red colour on the SalmoFan scale than those receiving the astaxanthin diet. No significant differences emerged in proximate composition and cholesterol content of trout in the two groups. The fatty acid profile of the fillets reflected the fatty acids of the diets administered to the trout: eicosapentaenoic, docosahexaenoic and docosapentaenoic acids and total n-3 polyunsaturated fatty acids were significantly higher in the fish fed the krill meal

Comparison of zootechnical performances, welfare condition and quality traits of hybrid striped bass (Morone chrysops x Morone saxatilis) reared in different Italian farms.

Growth performances of sunshine bass (initial m.b.w.=200\ub150 g) were examined in 3 different rearing conditions: concrete square basins (HSB-1); raceways (HSB-2); natural ponds (HSB-3). Fish received the same extruded feed (prot. 48.8%; lip. 17.8%). The trial lasted 16 months in HSB-1 and HSB-2 and 12 months in HSB-3 due to unfavourable welfare status and low growth performances. At harvest (16 months), sunshine bass reached a satisfactory mean weight without significant differences between groups. HSB-2 fish were longer with a smaller circumference, probably due to different hydrodynamics of the raceway. Glucose, cholesterol, triglycerides, protein, lactic dehydrogenase (LDH), aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), creatine kinase (CK), glycogen of plasma or tissue were not affected by rearing conditions as well as the proximate composition and the fatty acid profile of the fillet