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)

Largemouth bass (Micropterus salmoides Lacépède): reproduction management and larval rearing in Italy

Micropterus salmoides (Lacépède) was originally present into the waters of the eastern United States of America, northern Mexico and southern Canada. This species can be distinguished from the other black basses by the fact that its mouth extends to and beyond the edge of the eye and the first and the second dorsal fins are almost separated by a deep dip and there are no scales on the soft rayed of the second dorsal fin

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

Transcriptional alteration of gene biomarkers in hemocytes of wild ostrea edulis with molecular evidence of infections with bonamia spp. And/or marteilia refringens parasites

The European flat Ostrea edulis is highly susceptible to intracellular parasitic infections, particularly bonamiosis and marteiliosis. The defensive response of oyster to both bonamiosis and marteiliosis is typically mediated by hemocytes, which play a pivotal role in immune system homeostasis. In the present study, we first used a DNA-based tool in order to rapidly and specifically detect the presence of parasites in oysters from natural banks in the middle Adriatic Sea. In a second step, we used qRT-PCR to analyze the mRNA levels of a set of genes (i.e., superoxide dismutase (SOD), glutathione S-transferase (GST), metallothionein (MT), heat shock protein (HSP) 70 and 90, inhibitor of apoptosis (IAP), fas ligand (FAS), galectin (GAL) and extracellular superoxide dismutase (Ec-SOD)) expressed by hemocytes of flat oysters infected by the parasites, present singularly or in combination, compared to hemocytes from non-infected specimens. The results indicate that the presence of parasite DNA may be associated to a general upregulation of host genes related to apoptosis, detoxification and oxidative stress protection, with the exception of Ec-SOD, whose trend to a downregulation might reflect a mechanism for parasite escape before internalization

Correction to: Quality traits of raw and cooked cupped oysters

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Natural and synthetic pigments used in the pink-red coloration of salmon flesh: methodology of quali-quantitative assessments and sampling results

In Europe Atlantic salmon leads the first position in the farmed species contest with more than 763,000t (FES, 2007). In the year 2006, Norway produced alone beyond 603,000t followed by the United Kingdom with 128,000t. In these last years, the demand of organic salmon is gradually increased both in domestic and foreign markets. In these fish the pink-red coloration of flesh is obtained by supplementing the feed with shrimp waste meal. In Italy, Coop Italia since three years has started the commercialization in the context of "prodotti a marchio" of Atlantic salmon farmed following prescriptions reported in terms of specification that prohibits the use of synthetic and GM pigments in the feeds. In collaboration with this supermarket company, the Faculty of Veterinary Medicine of Camerino University carried out the quali-quantitative assessments on the presence of molecules and relative isomers that distinguish the natural carotenoid pigment from the synthetic one. Skinned portion of fillet (10g) were collected from dorsal muscle (retro-cranial, central and caudal region), mixed and homogenized and repeatedly extracted with acetone until they were colourless. The pooled extract were filtered and an aliquot (10ml) was centrifugated (2200xg, 5min). The astaxanthin content in the supernatant was determined by HPLC using a Varian ProStar instrument equipped with UV/vis detector using an external astaxanthin standard at detection wavelength 470nm. Analysis was performed on a Varian Kromasil 100 C 18 250x0.3 mm according to Bjerkeng et al. (1997). Identification and determination of stereoisomers were carried out by means of a Sumichiral a-phenylglicine 250x4.6mm column following Abu-Lafi and Turujman method (1999). The analysis performed on all the organic fish have demonstrated the exclusive content of natural pigment. In this group (b.w.=3.9-4.4kg), C-Card for salmonids ranged between 26±1 in 2004 and 21.5±1.3 in 2005 and 21.5±2.1 in 2006. Astaxanthin and isomers decreased from 5.6±0.3mg/kg in 2004 to 2.9±1.1mg/kg in 2006. The low-cost non organic salmon group (b.w.=4.5-4.6kg) resulted pigmented only with synthetic carotenoids and C-card for salmonids ranged between 27.3 in 2004 and 23.7 in 2005 whereas in 2006 it was observed equal to 27. Also in this batch, astaxanthin and isomers decreased passing from 6.5mg/kg in 2004 to 4.9mg/kg in 2006

A convenient and robust in vivo reporter system to monitor gene expression in the human pathogen helicobacter pylori

Thirty years of intensive research have significantly contributed to our understanding of Helicobacter pylori biology and pathogenesis. However, the lack of convenient genetic tools, in particular the limited effectiveness of available reporter systems, has notably limited the toolbox for fundamental and applied studies. Here, we report the construction of a bioluminescent H. pylori reporter system based on the Photorhabdus luminescens luxCDABE cassette. The system is constituted of a promoterless lux acceptor strain in which promoters and sequences of interest can be conveniently introduced by double homologous recombination of a suicide transformation vector. We validate the robustness of this new lux reporter system in noninvasive in vivo monitoring of dynamic transcriptional responses of inducible as well as repressible promoters and demonstrate its suitability for the implementation of genetic screens in H. pylori. © 2012, American Society for Microbiology

Strategies to improve the postharvest management of flat oyster (Ostrea edulis) from aquaculture using the short-term storage and package in an innovative closed-circuit system

This study aimed to improve postharvest management of flat oysters reared in a longline system in the mid Adriatic Sea, using short-term storage and package in an innovative closed-circuit system. For the trial, 870 oysters were employed, divided into three experimental groups (A, B, and C), N = 270 oysters each group, whereas the remaining 60 oysters were used for the 2 controls. Each group differed in relation to the time spent in the depuration tank and the time of packaging: group A was packed and immediately transferred to the cell; group B was depurated in a tank for 48 h, then packed and transferred to the cell; group C was depurated in a tank for 48 h and then packed, depurated for another 24 h and transferred to a cell. Samples of each group were sampled at different times of permanence in cell (t0) up until 12 days (t12) for biomorphometric, sensorial, nutritional, and microbiological analysis. Although the nutritional and sensorial quality of the oysters was more pronounced in group A, B and C groups also showed good results. In these two groups, thanks to the use of the modern water recirculation system the quality and safety of oysters was improved by reducing the presence of sludge and eliminating fecal contaminants completely than A treatment and seawater control. These results were also confirmed by the tank control, where a more extended depuration period positively influenced the same parameters emphasizing the importance of the adequate depuration processes in oyster productio

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