Anionic lipopeptides from Bacillus mojavensis I4 as effective antihypertensive agents: Production,characterization, and identification

A new isolated Bacillus mojavensis strain I4 was found as producer of biosurfactants by different screening methods, such as parafilm M test, hemolytic activity, oil displacement test, emulsification index, surface tension, and lipase production assay. Enhanced biosurfactants production was obtained using glucose and glutamic acid as carbon and nitrogen sources, respectively. The optimal production of the biosurfactants was obtained by using a C/N ratio of 17, pH of 7.0, and temperature of 37°C. The surface tension was reduced to 29 mN/m and the emulsification index E24 of 62% was achieved after 72 h of culture. The purified biosurfactants showed stability with regard to surface tension reduction and emulsification in a wide range of temperatures (4–120°C), pH (4–10), and salinity (2–12% of NaCl). The thin‐layer chromatography showed that the produced biosurfactants were lipopeptides. The biosurfactants were characterized as a group of anionic lipopeptides with zeta potential measurement. Chromatographic characterization using HPLC revealed that I4 lipopeptides contained numerous isoforms and surfactin was the major component. Moreover, the I4 lipopeptides showed interesting angiotensin‐converting enzyme‐inhibitory activity.     

Phylogenetic Analysis and Epidemic History of Hepatitis C Virus Genotype 2 in Tunisia,North Africa

HCV genotype 2 (HCV-2) has a worldwide distribution with prevalence rates that vary from country to country. High genetic diversity and long-term endemicity were suggested in West African countries. A global dispersal of HCV-2 would have occurred during the 20^th century, especially in European countries. In Tunisia, genotype 2 was the second prevalent genotype after genotype 1 and most isolates belong to subtypes 2c and 2k. In this study, phylogenetic analyses based on the NS5B genomic sequences of 113 Tunisian HCV isolates from subtypes 2c and 2k were carried out. A Bayesian coalescent-based framework was used to estimate the origin and the spread of these subtypes circulating in Tunisia. Phylogenetic analyses of HCV-2c sequences suggest the absence of country-specific or time-specific variants. In contrast, the phylogenetic grouping of HCV-2k sequences shows the existence of two major genetic clusters that may represent two distinct circulating variants. Coalescent analysis indicated a most recent common ancestor (tMRCA) of Tunisian HCV-2c around 1886 (1869–1902) before the introduction of HCV-2k in 1901 (1867–1931). Our findings suggest that the introduction of HCV-2c in Tunisia is possibly a result of population movements between Tunisia and European population following the French colonization.     

Analysis of skewed X-chromosome inactivation in females with rheumatoid arthritis and autoimmune thyroid diseases

Introduction  

The majority of autoimmune diseases such as rheumatoid arthritis (RA) and autoimmune thyroid diseases (AITDs) are characterized by a striking female predominance superimposed on a predisposing genetic background. The role of extremely skewed X-chromosome inactivation (XCI) has been questioned in the pathogenesis of several autoimmune diseases.     

Rescue of tumor-infiltrating lymphocytes from activation-induced cell death enhances the antitumor CTL response in CD5-deficient mice

The CD5 coreceptor is expressed on all T cells and on the B1a B cell subset. It is associated with TCR and BCR, and modulates intracellular signals initiated by both Ag receptor complexes. Human CD5 contributes to regulation of the antitumor immune response and susceptibility of specific CTL to activation-induced cell death (AICD) triggered by the tumor. In this study, we compared the T cell response to the B16F10 melanoma engrafted into CD5-deficient and wild-type C57BL/6 mice. Compared with wild-type mice, CD5 knockout animals displayed delayed tumor growth, associated with tumor infiltration by T cell populations exhibiting a more activated phenotype and enhanced antitumor effector functions. However, control of tumor progression in CD5(-/-) mice was transient due to increased AICD of CD8(+) tumor-infiltrating T lymphocytes. Remarkably, in vivo protection of T cells from TCR-mediated apoptosis by an adenovirus engineered to produce soluble Fas resulted in a dramatic reduction in tumor growth. Our data suggest that recruitment of tumor-specific T cells in the tumor microenvironment occurs at early stages of cancer development and that tumor-mediated AICD of tumor-infiltrating T lymphocytes is most likely involved in tumor escape from the immune system.     

Multiple bud cultures of 'Barhee' date palm (Phoenix dactylifera) and physiological status of regenerated plants

Adventitious bud clusters of date palm ‘Barhee’ were successfully established from juvenile leaves (<1 cm) using reduced amounts of 2,4-D (0.2 mg L⁻¹) to limit the risk of somaclonal variation. An average of 8.4 adventitious buds per explant were obtained. Histological examination showed that the superficial cell layers of leaves had the highest caulogenic capacity. High sucrose concentration (70 g L⁻¹) was used for the conversion of initial buds to multiple bud clusters. The promoting effect of temporary immersion on shoot proliferation was found to be significant when compared to cultivation on solid media. Elongation of shoots was also better using a thin film of PGR-free liquid medium instead of a solid medium. Anatomical observations indicated that roots from vitroplants were potentially functional at various developmental stages. However, only 12-month-old vitroplants were found to be physiologically able to control transpirational vapor loss. Additionally, the photochemical activity of photosystem II in these vitroplants was close to that measured in plants that were already acclimatized. As a result, 83.3% of regenerated plants were successfully acclimatized. No phenotypic variation was observed among more than 500 adventitious bud-derived plants. All regenerants survived after field transplantation. We found that the production of adventitious bud clusters in small bioreactors was able to provide an efficient micropropagation system for date palm cv. ‘Barhee’. An in vitro hardening step was a prerequisite for the successful transfer of vitroplants in soil.     

Physiological changes and essential oil composition of clary sage (<Emphasis Type="Italic">Salvia sclarea</Emphasis> L.) rosette leaves as affected by salinity

Since soil salinity is a widespread problem, we proposed to focus on its effect on seedling growth, mineral composition and particularly on essential oil composition known to be reliable to abiotic conditions. Clary sage seedlings were hydroponically cultivated under different salt concentrations (0, 25, 50, and 75 mM NaCl). The dry biomass and the mineral element contents were determined. The essential oils were extracted and analyzed by GC and GC–MS. Results showed that growth was reduced by 42% at 75 mM. This growth decrease was accompanied by a decrease in tissue hydration and a slight restriction in K⁺ uptake, as well as an increase in Na⁺ levels. Concerning essential oil yields, the application of 25 mM NaCl increased significantly the oil yield which decreased with increasing salt concentration. Besides, the chemical composition of clary sage was found to be also strongly affected by salt treatment since each salt concentration appeared to induce a different new chemotype in clary sage essential oil.     

Moroccan Leishmania infantum: Genetic Diversity and Population Structure as Revealed by Multi-Locus Microsatellite Typing

Leishmania infantum causes Visceral and cutaneous leishmaniasis in northern Morocco. It predominantly affects children under 5 years with incidence of 150 cases/year. Genetic variability and population structure have been investigated for 33 strains isolated from infected dogs and humans in Morocco. A multilocus microsatellite typing (MLMT) approach was used in which a MLMtype based on size variation in 14 independent microsatellite markers was compiled for each strain. MLMT profiles of 10 Tunisian, 10 Algerian and 21 European strains which belonged to zymodeme MON-1 and non-MON-1 according to multilocus enzyme electrophoresis (MLEE) were included for comparison. A Bayesian model-based approach and phylogenetic analysis inferred two L.infantum sub-populations; Sub-population A consists of 13 Moroccan strains grouped with all European strains of MON-1 type; and sub-population B consists of 15 Moroccan strains grouped with the Tunisian and Algerian MON-1 strains. Theses sub-populations were significantly different from each other and from the Tunisian, Algerian and European non MON-1 strains which constructed one separate population. The presence of these two sub-populations co-existing in Moroccan endemics suggests multiple introduction of L. infantum from/to Morocco; (1) Introduction from/to the neighboring North African countries, (2) Introduction from/to the Europe. These scenarios are supported by the presence of sub-population B and sub-population A respectively. Gene flow was noticed between sub-populations A and B. Five strains showed mixed A/B genotypes indicating possible recombination between the two populations. MLMT has proven to be a powerful tool for eco-epidemiological and population genetic investigations of Leishmania.     

Metaphyseal Dysplasia with Maxillary Hypoplasia and Brachydactyly Is Caused by a Duplication in RUNX2

Metaphyseal dysplasia with maxillary hypoplasia and brachydactyly (MDMHB) is an autosomal-dominant bone dysplasia characterized by metaphyseal flaring of long bones, enlargement of the medial halves of the clavicles, maxillary hypoplasia, variable brachydactyly, and dystrophic teeth. We performed genome-wide SNP genotyping in five affected and four unaffected members of an extended family with MDMHB. Analysis for copy-number variations revealed that a 105 kb duplication within RUNX2 segregated with the MDMHB phenotype in a region with maximum linkage. Real-time PCR for copy-number variation in genomic DNA in eight samples, as well as sequence analysis of fibroblast cDNA from one subject with MDMHB confirmed that affected family members were heterozygous for the presence of an intragenic duplication encompassing exons 3 to 5 of RUNX2. These three exons code for the Q/A domain and the functionally essential DNA-binding runt domain of RUNX2. Transfection studies with murine Runx2 cDNA showed that cellular levels of mutated RUNX2 were markedly higher than those of wild-type RUNX2, suggesting that the RUNX2 duplication found in individuals with MDMHB leads to a gain of function. Until now, only loss-of-function mutations have been detected in RUNX2; the present report associates an apparent gain-of-function alteration of RUNX2 function with a distinct rare disease.