Isolation and partial characterization of bacteria (Pseudoalteromonas sp.) with potential antibacterial activity from a marine costal environment from New Caledonia.

UNLABELLED: Marine bacteria are a rich source of bioactive metabolites. However, the microbial diversity of marine ecosystem still needs to be explored. The aim of this study was to isolate and characterize bacteria with antimicrobial activities from various marine coastal environment of New Caledonia. We obtained 493 marine isolates from various environments and samples of which 63 (12.8%) presented an antibacterial activity against a panel of reference pathogenic strains (Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and Enterococcus faecalis). Ten out of the most promising strains were cultured, fractionated and screened for antibacterial activity. Four of them (NC282, NC412, NC272 and NC120) showed at least an activity against reference and multidrug-resistant pathogenic strains and were found to belong to the genus Pseudoalteromonas, according to the 16S phylogenetic analysis. The NC282 strain does not belong to any described Pseudoalteromonas species and might be of interest for further chemical and biological characterization. These findings suggest that the identified strains may contribute to the discovery for new sources of antimicrobial substances to develop new therapies to treat infections caused by multidrug-resistant bacteria. SIGNIFICANCE AND IMPACT OF THE STUDY: With the constant increasing of bacterial resistance against known antibiotics in worldwide public health, it is now necessary to find new sources of antimicrobials. Marine bacteria from New Caledonia were isolated, tested for antibacterial activity and characterized to find new active molecules against multidrug-resistant bacteria. This study illustrates the diversity of the marine ecosystem with potent new bacteria species. Also the potential of marine bacteria as a rich source of bioactive molecule, for example antibiotics, is highlighted.

Representational difference analysis of cDNA identifies novel genes expressed following preconditioning of the heart.

Preconditioning of the myocardium rapidly induces a number of transcription factors, which are likely to be responsible for a cascade of transcriptional changes underlying the development of delayed adaptation. Identifying these changes provides insight into the molecular pathways elicited by sub-lethal ischaemia and the mechanism leading to delayed adaptation. Genes up-regulated in rabbit myocardium in vivo by ischaemic preconditioning following reperfusion for 2 h, 4 h and 6 h post-treatment were identified by representational difference analysis of cDNA (cDNA. RDA). The area of the left ventricle rendered ischaemic by preconditioning or the equivalent area of sham-treated animals was isolated and cDNA.RDA performed. Three novel genes and six genes with known function where identified, including the TGFbeta receptor interacting protein 1, the alpha isoform of the A subunit of PP2 and the cap binding protein NCBP1. To determine whether expression of these genes correlated with preconditioning per se, expression was measured in myocardium after both ischaemic as well as heat shock induced preconditioning following 2 h, 4 h, and 6 h reperfusion. These genes were induced in rabbit myocardium in vivo by both ischaemia and heat shock, consistent with a fundamental role in the development of delayed adaptation. The well described role of PP2 in modulating the mitogen-activated protein kinase pathway and promoting cell survival is consistent with our previous work, which identified the reperfusion injury salvage kinase pathway in mediating the protective effects of ischaemic preconditioning. Expression of Trip1 and Ncbp1 also implicates TGFbeta signalling pathways and RNA processing and transport in delayed adaptation to stress in the myocardium.

Synthesis and antiviral evaluation of nucleic acid-based (NAB) libraries.

Combinatorial assembly of nucleotide libraries and their antiviral evaluation against HSV-1 are described.

Simple and rapid combined genetic diagnosis of mutation (1691 G-->A) of the factor V gene and (20210 G-->A) of the prothrombin gene.

We have developed a rapid method which allows us simultaneously to determine two genetic variations that are associated with an increased risk of venous thrombosis: the 20210 G-->A mutation present in the 3'-UT region of the prothrombin gene and the 1691 G-->A mutation giving rise to factor V Leiden. Our strategy involves the coamplification of exon 10 of the factor V gene and of the region 3' from the prothrombin gene using modified oligonucleotides, permitting the introduction of a single HindIII cleavage site in fragments bearing one of the mutations. As a result of its time- and cost-saving features, this combined method should be considered for screening large numbers of patients.

Association of genetic polymorphisms in the ACE, ApoE, and TGF beta genes with early onset ischemic heart disease.

BACKGROUND: The genetic factors that contribute to ischemic heart disease (IHD) are poorly understood, and it is likely that multiple genes acting independently or synergistically contribute to the risk of IHD and outcome. The genes for angiotensin-converting enzyme (ACE) and apolipoprotein E (ApoE) have been implicated independently in the risk of IHD. HYPOTHESIS: This study examined whether genetic polymorphisms in the ACE and ApoE genes are associated with early onset IHD. Polymorphisms in a third gene, transforming growth factor beta 2 (TGF beta 2), with a known role in wound repair and cardiac development, are also examined with respect to early onset IHD. METHODS: In all, 101 patients with IHD and onset of disease before 55 years for men and 60 years for women, and 100 controls with angiographically confirmed normal coronary arteries were recruited for this study. The ACE, ApoE, and TGF beta 2 genotypes were determined by polymerase chain reaction amplification or Southern blotting and were compared with the patient's clinical and family histories. RESULTS AND CONCLUSION: The frequency of the ACE D allele was significantly lower in the patient group (0.475) than in the control group (0.59, p = 0.03), which was attributed to a reduction in the number of patients with the DD genotype (patients: 24% DD, controls: 33% DD). Sudden cardiac death was also associated with the DD genotype. These data are consistent with the ACE D allele contributing to a fatal outcome. No association between the DD genotype and risk of myocardial infarction, presenting age, extent of vessel disease, family history, hypertension, or hypercholesterolemia was seen. Analysis of the ApoE genotype showed no association with early onset IHD. There was no evidence for a synergistic effect between the ACE and ApoE genotypes on the risk of early onset IHD. A polymorphism in the TGF beta 2 gene was rare and not associated with early onset IHD.

Inhibition of protein synthesis by the human immunodeficiency virus type 1 nef gene product.

During productive infection of human T lymphocytes in cell culture, the expression of human immunodeficiency virus type 1 is temporally regulated by virus-encoded regulatory proteins. Among these Nef, whose function has not been clearly elucidated, is thought to alter CD4+ T cells. We examined the possibility that the nef gene interferes with the translation process in a cell-free system. The results demonstrate that the nef gene product mediates an inhibitory effect on protein synthesis. Conversely, the use of antisense nef mRNA did not affect translation. Further observations suggest that this inhibitory effect is an inherent property of the nef gene product itself and not of its mRNA. The data show that the translational repression directed by Nef is a general phenomenon, acting on its own and on other messengers used as reporter mRNAs. We propose that, as a consequence, Nef can play an important role in the pathogenesis of AIDS.