The changing spectrum of arrhythmogenic (right ventricular) cardiomyopathy

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a clinically and genetically heterogeneous heart muscle disorder associated with ventricular arrhythmias and risk of sudden death. The disease is heredo-familial, and mutations in desmosomal genes have been identified in about half of patients. Recent experimental models confirm this disease develops after birth due to progressive myocardial dystrophy. Genotype-phenotype correlations, including magnetic resonance and pathology studies on heart specimens, are currently demonstrating that the spectrum of the disease is wider than initially thought and usually referred to with the adjective "right ventricular", with the evidence of biventricular or even isolated left ventricular forms, so that it is increasingly identified simply as "arrhythmogenic cardiomyopathy". A revision of the diagnostic criteria encompassing familial, electrocardiographic, arrhythmic, morpho-functional and histopathologic findings, has been made to improve diagnostic sensitivity and specificity, in particular of the concealed forms and left-dominant subtypes of the disease. Experimental models are mandatory to gain an insight into the cascade of cellular and molecular events leading from gene defect to myocardial dystrophy in ARVC.     

Sad3 and sad4 are required for saponin biosynthesis and root development in oat

Avenacins are antimicrobial triterpene glycosides that are produced by oat (Avena) roots. These compounds confer broad-spectrum resistance to soil pathogens. Avenacin A-1, the major avenacin produced by oats, is strongly UV fluorescent and accumulates in root epidermal cells. We previously defined nine loci required for avenacin synthesis, eight of which are clustered. Mutants affected at seven of these (including Saponin-deficient1 [Sad1], the gene for the first committed enzyme in the pathway) have normal root morphology but reduced root fluorescence. In this study, we focus on mutations at the other two loci, Sad3 (also within the gene cluster) and Sad4 (unlinked), which result in stunted root growth, membrane trafficking defects in the root epidermis, and root hair deficiency. While sad3 and sad4 mutants both accumulate the same intermediate, monodeglucosyl avenacin A-1, the effect on avenacin A-1 glucosylation in sad4 mutants is only partial. sad1/sad1 sad3/sad3 and sad1/sad1 sad4/sad4 double mutants have normal root morphology, implying that the accumulation of incompletely glucosylated avenacin A-1 disrupts membrane trafficking and causes degeneration of the epidermis, with consequential effects on root hair formation. Various lines of evidence indicate that these effects are dosage-dependent. The significance of these data for the evolution and maintenance of the avenacin gene cluster is discussed.     

Study of the ecology of fresh sausages and characterization of populations of lactic acid bacteria by molecular methods

In this study, a polyphasic approach was used to study the ecology of fresh sausages and to characterize populations of lactic acid bacteria (LAB). The microbial profile of fresh sausages was monitored from the production day to the 10th day of storage at 4 degrees C. Samples were collected on days 0, 3, 6, and 10, and culture-dependent and -independent methods of detection and identification were applied. Traditional plating and isolation of LAB strains, which were subsequently identified by molecular methods, and the application of PCR-denaturing gradient gel electrophoresis (DGGE) to DNA and RNA extracted directly from the fresh sausage samples allowed the study in detail of the changes in the bacterial and yeast populations during storage. Brochothrix thermosphacta and Lactobacillus sakei were the main populations present. In particular, B. thermosphacta was present throughout the process, as determined by both DNA and RNA analysis. Other bacterial species, mainly Staphylococcus xylosus, Leuconostoc mesenteroides, and L. curvatus, were detected by DGGE. Moreover, an uncultured bacterium and an uncultured Staphylococcus sp. were present, too. LAB strains isolated at day 0 were identified as Lactococcus lactis subsp. lactis, L. casei, and Enterococcus casseliflavus, and on day 3 a strain of Leuconostoc mesenteroides was identified. The remaining strains isolated belonged to L. sakei. Concerning the yeast ecology, only Debaryomyces hansenii was established in the fresh sausages. Capronia mansonii was initially present, but it was not detected after the first 3 days. At last, L. sakei isolates were characterized by randomly amplified polymorphic DNA PCR and repetitive DNA element PCR. The results obtained underlined how different populations took over at different steps of the process. This is believed to be the result of the selection of the particular population, possibly due to the low storage temperature employed.     

Molecular Detection and Identification of Brettanomyces/Dekkera bruxellensis and Brettanomyces/Dekkera anomalus in Spoiled Wines

In this paper we describe the development of a PCR protocol to specifically detect Brettanomyces bruxellensis and B. anomalus. Primers DB90F and DB394R, targeting the D1-D2 loop of the 26S rRNA gene, were able to produce amplicons only when the DNA from these two species were used. No amplification product was obtained when DNA from other Brettanomyces spp. or wine yeasts were used as the templates. The 305-bp product was subjected to restriction enzyme analysis with DdeI to differentiate between B. bruxellensis and B. anomalus, and each species could be identified on the basis of the different restriction profiles. After optimization of the method by using strains from international collections, wine isolates were tested with the method proposed. Total agreement between traditional identification and molecular identification was observed. The protocol developed was also used for direct detection of B. bruxellensis and B. anomalus in wines suspected to be spoiled by Brettanomyces spp. Application of culture-based and molecular methods led us to the conclusion that 8 of 12 samples were spoiled by B. bruxellensis. Results based on the application of molecular methods suggested that two of the eight positive samples had been infected more recently, since specific signals were obtained at both the DNA and RNA levels.     

SUMOylation Is Required for Optimal TRAF3 Signaling Capacity

TNF receptor–associated factors (TRAFs) are multifunctional adaptor proteins involved in temporal and spatial coordination of signals necessary for normal immune function. Here, we report that TRAF3, a TRAF family member with a key role in Toll-like and TNF family receptor signaling and suppressor of lymphomagenesis, is post-translationally modified by the small ubiquitin-related modifier (SUMO). Through yeast two-hybrid and co-immunoprecipitation assays we have identified Ubc9, the SUMO conjugating enzyme, as a novel TRAF3-interacting protein. We show that Ubc9-dependent SUMOylation of TRAF3 modulates optimal association with the CD40 receptor, thereby influencing TRAF3 degradation and non-canonical NF-κB activation upon CD40 triggering. Collectively, our findings describe a novel post-translational modification of a TRAF family member and reveal a link between SUMOylation and TRAF-mediated signal transduction.     

Polyamines in the photosynthetic apparatus

The three main polyamines putrescine (Put), spermidine (Spd) and spermine (Spm) were characterized by HPLC in intact spinach leaf cells, intact chloroplasts, thylakoid membranes, Photosystem II membranes, the light-harvesting complex and the PS II complex. All contain the three polyamines in various ratios; the HPLC polyamine profiles of highly resolved PS II species (a Photosystem II core and the rection center) suggest an enrichment in the polyamine Spm.Abbreviations Chl chlorophyll - HPLC high performance liquid chromatography - LHC light-harvesting complex - PS II Photosystem II - PS II-RC Photosystem II reaction center - Put putrescine - Spd spermidine - Spm spermine - 10%S-core D₁-D₂-Cyt b559-47 kD-43 kD complex     

VDR TaqI is associated with obesity in the Greek population

The prevalence of obesity has increased dramatically during the last thirty years in western countries with severe complications for health and economy. Obesity is the outcome of the strong interplay between genetic and environmental factors and is therefore widely expected that the discovery of the many genetic factors underlying the heritable risk of obesity will contribute critically to our basic knowledge of the disease etiopathogenesis and the identification of new targets for therapeutic intervention. The aim of the present study was to assess the genetic contribution of known polymorphisms in two genes that are linked to the pathogenetic mechanism of obesity. Analysis of vitamin D receptor (VDR) TaqI (rs731236; T/C) and fat mass and obesity-associated (FTO) (rs9930506; A/T) polymorphisms in 82 obesity subjects and 102 controls showed significant association for VDR TaqI ‘T’ allele and obesity (OR: 2.07; 1.123–3.816; P = 0.019), contributing to an elevated BMI of 3 kg/m² per risk allele. No association was observed for the FTO polymorphism. These results further support a role for VDR as risk factor for obesity and suggest its further validation in larger independent populations as well as highlight a target for functional analysis towards therapeutic intervention in obese individuals.     

Nickel-quinolones interaction: Part 3 — Nickel(II) complexes of the antibacterial drug flumequine

Nickel(II) complexes with the first-generation quinolone antibacterial agent flumequine in the presence or absence of nitrogen donor heterocyclic ligands (4-benzylpyridine, pyridine, 2,2′-bipyridine or 1,10-phenanthroline) have been structurally characterized by physicochemical and spectroscopic techniques. The experimental data suggest that flumequine acts as deprotonated bidentate ligand coordinated to Ni(II) through the carboxylato and ketone oxygen atoms. The crystal structures of bis(4-benzylpyridine)bis(flumequinato)nickel(II) 2, (2,2′-bipyridine)bis(flumequinato)nickel(II) 4 and (1,10-phenanthroline)bis(flumequinato)nickel(II) 5 have been determined by X-ray crystallography and are the first crystal structures of flumequinato complexes reported. UV study of the interaction of the complexes with calf-thymus DNA (CT DNA) has shown that the complexes bind to CT DNA and bis(aqua)bis(flumequinato)nickel(II) exhibits the highest binding constant to CT DNA. Competitive study with ethidium bromide (EB) has shown that the complexes can displace the DNA-bound EB indicating that they bind to DNA in strong competition with EB. The cyclic voltammograms of the complexes recorded in DMSO solution and in 1/2 DMSO/buffer (containing 150 mM NaCl and 15 mM trisodium citrate at pH 7.0) solution have shown that in the presence of CT DNA they bind to CT DNA by the intercalative binding mode. The complexes exhibit good binding propensity to human or bovine serum albumin protein having relatively high binding constant values.