A two-component regulatory system playing a critical role in plant pathogens and endosymbionts is present in Brucella abortus and controls cell invasion and virulence

Two mutants showing increased sensitivity to polycations and surfactants were obtained by transposon mutagenesis of virulent Brucella abortus 2308 Nal^r. These mutants showed no obvious in vitro growth defects and produced smooth-type lipopolysaccharides. However, they hardly multiplied or persisted in mouse spleens, displayed reduced invasiveness in macrophages and HeLa cells, lost the ability to inhibit lysosome fusion and were unable to replicate intracellularly. Subsequent DNA analyses identified a two-component regulatory system [ Brucella virulence related (Bvr)] with a regulatory (BvrR) and sensory (BvrS) protein. Cloning of bvrR in the BvrR-deficient mutant restored the resistance to polycations and, in part, the invasiveness and the ability to multiply intracellularly. BvrR and BvrS were highly similar (87–89% and 70–80% respectively) to the regulatory and sensory proteins of the chromosomally encoded Rhizobium meliloti ChvI–ExoS and Agrobacterium tumefaciens ChvI–ChvG systems previously shown to be critical for endosymbiosis and pathogenicity in plants. Divergence among the three sensory proteins was located mostly within a periplasmic domain probably involved in stimulus sensing. As B. abortus , R. meliloti and A. tumefaciens are phylogenetically related, these observations suggest that these systems have a common ancestor that has evolved to sense stimuli in plant and animal microbial environments.     

A ‘higher order’ of telomere regulation: telomere heterochromatin and telomeric RNAs

Protection of chromosome ends from DNA repair and degradation activities is mediated by specialized protein complexes bound to telomere repeats. Recently, it has become apparent that epigenetic regulation of the telomric chromatin template critically impacts on telomere function and telomere‐length homeostasis from yeast to man. Across all species, telomeric repeats as well as the adjacent subtelomeric regions carry features of repressive chromatin. Disruption of this silent chromatin environment results in loss of telomere‐length control and increased telomere recombination. In turn, progressive telomere loss reduces chromatin compaction at telomeric and subtelomeric domains. The recent discoveries of telomere chromatin regulation during early mammalian development, as well as during nuclear reprogramming, further highlights a central role of telomere chromatin changes in ontogenesis. In addition, telomeres were recently shown to generate long, non‐coding RNAs that remain associated to telomeric chromatin and will provide new insights into the regulation of telomere length and telomere chromatin. In this review, we will discuss the epigenetic regulation of telomeres across species, with special emphasis on mammalian telomeres. We will also discuss the links between epigenetic alterations at mammalian telomeres and telomere‐associated diseases.     

Analysis of the oviductal glycoprotein 1 polymorphisms and their effects on components of litter size in rabbits

The objective of this work was to study the effect of the oviductal glycoprotein 1 ( OVGP1 ) genotype and mRNA expression on litter size and other fertility measures, as OVGP1 has positive effects on fertilization and early embryo development. We have analysed an F₂ cross of two lines of rabbits divergently selected for uterine capacity. The OVGP1 mRNA expression was analysed in both lines, but no differences were observed between them. The promoter region and mRNA were sequenced in the F₀ generation, and 17 polymorphic sites were found to co-segregate in three haplotypes (A, B and C). An association study was performed between several reproductive traits and a triallelic microsatellite identified in the promoter region as well as a non-synonymous SNP located in exon 11 [g.12944C>G (p.Arg468Gly)]. The alleles g.12944G and g.325(GT)₁₄T(G)₅ of the B haplotype have a positive effect on the total number of kits born, number born alive, number of implanted embryos and foetal and prenatal embryo survival.     

Vitamin D Status: A Different Story in the Very Young versus the Very Old Romanian Patients

BackgroundIn Romania (latitude 48°15’N to 43°40’N), vitamin D supplementation is common practice mostly in infants 0-1 year old. No published information is available regarding epidemiological data on vitamin D status in the Romanian population for a wide age range and geographical territory. In this context, we aimed to evaluate the seasonal and age variation of vitamin D status in a large Romanian population.Methods6631 individuals from across Romania had performed 7544 vitamin D assessments (2012-2014) in a chain of private laboratories. Vitamin D (25-hydroxyvitamin D2 and 25-hydroxyvitamin D3) was measured using High Performance Liquid Chromatography. Vitamin D levels were classified as severe deficiency<10ng/mL, deficiency 10-20ng/mL, insufficiency 21-29ng/mL, sufficiency≥30ng/mL and potentially harmful>100ng/ml.ResultsMale to female ratio was 1:2.9. Age ranged from 0 to 85 years. Mean vitamin D levels increased from April (26.3ng/ml) to September (35.6ng/ml) and decreased from October (33.5ng/ml) to March (24.4 ng/ml). Overall 40% had sufficient vitamin D, while the rest were insufficient 33%, deficient 22%, severely deficient 4% and 1% potentially harmful (of them 81% under 1 year old). Males compared to females showed higher percentages of sufficiency (47% vs. 38%). Children 0- 2 years presented the highest percentage of vitamin D sufficiency (77%). Lowest percentages (21%) of sufficiency were in people 80-84 years.ConclusionIn Romania, suboptimal vitamin D levels are common (59%), especially in older age, wintertime and in women. Vitamin D supplementation would be most warranted from January to April in the Romanian population. 25-hydroxyvitamin D levels>100ng/ml were relatively prevalent in children 0-1 year old (17.3%). This was attributed to supplementation errors and the fact that high-risk individuals were more likely to visit for medical check-up. Nonetheless, it stresses the need to increase awareness of the importance of preventing Vitamin D supplementation administration errors in the young.     

Sensitivity to antibiotics of Clostridium difficile toxigenic nosocomial strains

Clostridium difficile is the etiological agent of diarrhoea and colitis, especially in elderly patients. The incidence of these diseases has increased during the last 10 years. Emergence of so-called hypervirulent strains is considered as one of the main factors responsible for the more severe disease and changed profile of sensitivity to antimicrobial agents. The aim of this work was to determine the sensitivity profile of toxigenic strains of C. difficile in the Czech Republic in 2011–2012 to selected antibiotics. The antibiotics clindamycin, metronidazole, vancomycin and amoxicillin with clavulanic acid were used for this purpose. Isolates cultured on Brazier's C. difficile selective agar were analysed for the presence of toxin genes using Xpert detection system. Xpert analysis revealed that 33 strains carried the genes for toxins tcdB, cdt and tcdCΔ117, thus showing characteristics typical for the hypervirulent ribotype 027/PFGE type NAP1/REA type B1. The remaining 29 strains carried only the gene for toxin B (tcdB) and not cdt and tcdCΔ117. Our results indicate the higher susceptibility of C. difficile hypertoxigenic strains to three out of four tested antibiotics (except vancomycin) than it is for the other toxigenic strains. We found that only 10.34 % of other toxigenic strains were resistant to clindamycin, and no resistance was found in all other cases. All the isolates were sensitive to amoxicillin/clavulanic acid in vitro. However, its use is not recommended for therapy of infections caused by C. difficile.     

Gene expression changes in spleens of the wildlife reservoir species, Eurasian wild boar （Sus scrofa）, naturally infected with Brucella suis biovar 2

Brucella suis is responsible for swine brucellosis worldwide.Of the five different 8.suis biovars (bv.), bv.2 appears restricted to Europe where it is frequently isolated from wild boar and hares, can infect pigs and can cause human brucellosis.In this study, the differ-ential gene expression profile was characterized in spleens of Eurasian wild boar naturally infected with B.suis by.2.Of the 20,201 genes analyzed in the microarray, 633 and 1,373 were significantly (fold change＞1.8; P＜0.01) upregulated and downregulated, respectively,in infected wild boar.The analysis was focused on genes that were over represented after conditional test for biological process gene on-tology.Upregulated genes suggested that B.suis bv.2 infection induced cell maturation, migration and/or proliferation in infected animals.The genes downregulated in infected wild boar impaired the activity of several important cellular metabolic pathways such as metabolism,cytoskeleton organization and biogenesis, immune response and lysosomal function and vesicle-mediated transport.In addition, the re-sponse to stress, sperm fertility, muscle development and apoptosis seemed to be also impaired in infected animals.These results sug-gested that B.suis by.2 may use strategies similar to other smooth brucellae to facilitate intraeellular multiplication and the developmentof chronic infections.To our knowledge, this is the first report of the analysis of gene expression profile in hosts infected with B.suis by.2, which is important to understand the molecular mechanisms at the host-pathogen interface in the main reservoir species with possible implications in the zoonotic cycle of the pathogen.     

Nicotine-free and salt-tolerant tobacco plants obtained by grafting to salinity-resistant rootstocks of tomato

In this work we present the first study of the behaviour of tobacco plants, under saline conditions, grafted to salinity-resistant rootstocks of tomato cultivars. To test the viability and efficiency of this grafting technique in tobacco plants subjected to salinity, we analyse the production of foliar biomass and different quality parameters in this crop. With this aim, Nicotiana tabacum cv. Sevilla (scion) was grafted to two cultivars of Lycopersicum esculentum (rootstocks): cv. Jaguar (Sevilla/Jaguar) and cv. Brillante (Sevilla/Brillante). Furthermore, as controls, tobacco plants of cv. Sevilla were used grafted to themselves (Sevilla/Sevilla) and non-grafted plants of cv. Sevilla. Plants were grafted by needle graft following the procedure described by Rivero RM, Ruiz JM, Romero L (2002) Role of grafting in horticultural plants, pp 229–254. In the present work, we demonstrate that the graft of tobacco scions with tomato rootstocks is an effective agricultural approach to improve production and quality in tobacco leaves under conditions of saline stress. Our results show that the rootstock of the cv. Brillante best induced salt resistance in tobacco cv. Sevilla, registering the lowest foliar concentrations of Na⁺ and Cl^–, the lowest lipid peroxidation and the highest proline and sugar concentrations. Overall, this is reflected in better biomass production of the aerial part of the plant. Finally, it is noteworthy that grafting in tobacco plants to tomato rootstocks essentially eliminates foliar nicotine levels (reduced to 1%). These results are of great importance, as this technique implies a rapid, efficient and natural alternative in increasing tobacco-leaf quality and thus reducing harmful effects of this alkaloid on the health of smokers.