Chlamydia trachomatis: identification of susceptibility markers for ocular and sexually transmitted infection by immunogenetics

The aim of this review is to present a concise overview of all data available on the immunogenetics of Chlamydia trachomatis infections, both sexually transmitted urogenital and ocular infections. Currently, candidate gene approaches are used to identify genes related to the susceptibility to and severity of C. trachomatis infections. The main focus in the review will be on data obtained by the study of human cohorts.     

A euryhaline fish,lost in the desert: The unexpected metapopulation structure of Coptodon guineensis (Günther, 1862) in the Sebkha of Imlili

Euryhaline Cichlid fish of the species Coptodon guineensis are present in different water holes situated in a dried depression in the desert in the extreme South of Morocco, the Sebkha of Imlili. A genetic survey of this population, using complete sequences of the ND2 gene (mtDNA) and sixteen microsatellite loci, revealed that the fish in the sebkha did not form a single population, but rather a metapopulation. This metapopulational structure may be regarded as good news from the point of view of the conservation of fish in the sebkha. Although small individual populations may have short, finite life spans, the metapopulation as a whole is more stable, because immigrants from one population are likely to re-colonize the habitat, left open by the extinction of another.     

Diversity and spatial genetic structure of natural Moroccan <Emphasis Type="Italic">Quercus susber</Emphasis> L. assessed by ISSR markers for conservation

Morocco is one of the most important regions of the world in terms of Quercus suber L. number and variation. This species is in decline due to several factors, which can lead to permanent loss of this resource. It would be essential to evaluate the genetic diversity in order to conserve maximum genetic variability of this species. The genetic diversity and differentiation of 16 sites from five regions representing the entire range of Moroccan Cork Oak were assessed. Twenty-three ISSR primers used generated 985 polymorphic fragments with an average of 42.8 bands per primer and showed 100% of polymorphism. The 173 individuals revealed a moderate level of genetic diversity at species level (I?=?0.27, He?=?0.161). The AMOVA showed that the highest level of diversity occurred within populations (64%), this was also confirmed by the coefficient of differentiation (Gst?=?0.47). The estimated gene flow (Nm?=?0.56) and the Mantel test revealed a significant correlation between geographic and genetic diversity (r?=?0.266; p?=?0.001). This genetic structure was further shown by the topology of the UPGMA, sPCA and STRUCTURE analysis. In addition, a core collection of 34 genotypes was established representing the essential diversity detected. This research advocates populations and individuals to preserve in order to improve and conserve this resource in the future.     

Kosmotoga pacifica sp. nov., a thermophilic chemoorganoheterotrophic bacterium isolated from an East Pacific hydrothermal sediment

A novel strictly anaerobic thermophilic heterotrophic bacterium, strain SLHLJ1^T, was isolated from a Pacific hydrothermal sediment. Cells were Gram-negative coccobacilli (approximately 1.0 × 0.6 μm) with a toga. It grew at temperatures between 33 and 78 °C (optimum 70 °C). Elemental sulphur and l-cystine stimulated its growth. It contained C_16:0, C_16:1 ω11c, C_18:0 and C_18:1 ω9c as major fatty acids (>5 %), 3 phospholipids and 2 glycolipids as polar lipids. Its DNA G+C content was 43.7 mol%. Phylogenetic analyses based on 16S rRNA gene sequences placed strain SLHLJ1^T within the family Thermotogaceae. The novel isolate was most closely related to Kosmotoga arenicorallina (97.93 % 16S rRNA gene sequence similarity), K. olearia (92.43 %) and K. shengliensis (92.17 %). On the basis of phenotypic, chemotaxonomic and phylogenetic comparisons with its closest relatives, we propose its assignment to a novel species of the genus Kosmotoga. The name Kosmotoga pacifica sp. nov. is proposed with strain SLHLJ1^T (=DSM 26965^T = JCM 19180^T = UBOCC 3254^T) as the type species.     

Assessment of genetic diversity and population structure of an endemic Moroccan tree (<Emphasis Type="Italic">Argania spinosa</Emphasis> L.) based in IRAP and ISSR markers and implications for conservation

Argan Tree is well known for its precious oil extracted from its seeds particularly used for the nutritional and cosmetic benefits. Because of the high international demand, the argan tree suffers from overexploitation and its cultivation is rare. Thus, the assessment of the genetic variation of this endemic tree is critically important for designing conservation strategies. In the present study and for the first time, genetic diversity of the global natural distribution of argan tree (Argania spinosa L.) in Morocco was assessed. Four IRAP (inter-retrotransposon amplified polymorphism) primer combinations and seven ISSR (inter-simple sequence repeat) primers amplified 164 and 248 scorable polymorphic bands respectively. Polymorphic information content (PIC = 0.27), resolving power (Rp = 15) and marker index (MI = 10.81) generated by IRAP primer combinations were almost identical to those generated by ISSR primers (PIC = 0.27, Rp = 9.16 and MI = 12). AMOVA analysis showed that 49% of the genetic variation was partitioned within populations which is supported by Nei’s genetic differentiation (Gst = 0.5391) and the overall estimate of gene flow (Nm) being 0.4274. The STRUCTURE analysis, PCoA (principal coordinate analysis) and UPGMA (unweighted pair-group method with arithmetic mean) based on the combined data matrices of IRAP and ISSR divided the 240 argan genotypes into two groups. The strong differentiation observed might be due to the geographical distribution of argan tree. Our results provide crucial insight for genetic conservation programs of this genetic resource.     

PNA-binding glycans are expressed at high levels on horse mature and immature T lymphocytes and a subpopulation of B lymphocytes

In mammals, the binding of peanut agglutinin (PNA) on the plasma membrane defines subpopulations among lymphocytes from peripheral blood and lymphoid organs. PNA binds Gal 1,3GalNAc residues provided that they are not sialylated. Here, we studied the expression of PNA-binding glycans on healthy horse peripheral blood, thymus, lymph node and spleen lymphocytes. We first demonstrated the binding specificity of PNA for galactose residues by competition experiments and the inhibitory role of sialic acids in PNA binding by sialidase digestion. Unlike human and murine lymphocytes, all equine lymphocytes were found positive by flow cytometry analysis. Double-staining analyses showed that lymphocytes expressing high levels of PNA-binding glycans (PNA^high lymphocytes) were made up of the great majority of CD5⁺, CD4⁺ and CD8⁺ cells, and of 30 and 50% of sIg-bearing lymphocytes in peripheral blood and in lymph nodes or spleen, respectively. Lectin histochemistry suggested that lymph node germinal centres contained PNA^high B cells. Contrary to what is found in humans and mice, PNA staining intensity on CD5⁺, CD4⁺ and CD8⁺ cells did not differentiate immature from mature T lymphocytes in the equine thymus. The functional consequences of these differences are discussed. Published in 2005.     

Molecular Typing of Mycobacterium Tuberculosis Complex by 24-Locus Based MIRU-VNTR Typing in Conjunction with Spoligotyping to Assess Genetic Diversity of Strains Circulating in Morocco

Background

Standard 24-locus Mycobacterial Interspersed Repetitive Unit Variable Number Tandem Repeat (MIRU-VNTR) typing allows to get an improved resolution power for tracing TB transmission and predicting different strain (sub) lineages in a community.

Methodology

During 2010–2012, a total of 168 Mycobacterium tuberculosis Complex (MTBC) isolates were collected by cluster sampling from 10 different Moroccan cities, and centralized by the National Reference Laboratory of Tuberculosis over the study period. All isolates were genotyped using spoligotyping, and a subset of 75 was genotyped using 24-locus based MIRU-VNTR typing, followed by first line drug susceptibility testing. Corresponding strain lineages were predicted using MIRU-VNTRplus database.

Principal Findings

Spoligotyping resulted in 137 isolates in 18 clusters (2–50 isolates per cluster: clustering rate of 81.54%) corresponding to a SIT number in the SITVIT database, while 31(18.45%) patterns were unique of which 10 were labelled as “unknown” according to the same database. The most prevalent spoligotype family was LAM; (n = 81 or 48.24% of isolates, dominated by SIT42, n = 49), followed by Haarlem (23.80%), T superfamily (15.47%), >Beijing (2.97%), > U clade (2.38%) and S clade (1.19%). Subsequent 24-Locus MIRU-VNTR typing identified 64 unique types and 11 isolates in 5 clusters (2 to 3isolates per cluster), substantially reducing clusters defined by spoligotyping only. The single cluster of three isolates corresponded to two previously treated MDR-TB cases and one new MDR-TB case known to be contact a same index case and belonging to a same family, albeit residing in 3 different administrative regions. MIRU-VNTR loci 4052, 802, 2996, 2163b, 3690, 1955, 424, 2531, 2401 and 960 were highly discriminative in our setting (HGDI >0.6).

Conclusions

24-locus MIRU-VNTR typing can substantially improve the resolution of large clusters initially defined by spoligotyping alone and predominating in Morocco, and could therefore be used to better study tuberculosis transmission in a population-based, multi-year sample context.     

New evidence for nitrogen fixation within the Italian white truffle Tuber magnatum

Diversity of nitrogen-fixing bacteria and the nitrogen-fixation activity was investigated in Tuber magnatum, the most well-known prized species of Italian white truffle. Degenerate PCR primers were applied to amplify the nitrogenase gene nifH from T. magnatum ascomata at different stages of maturation. Putative amino acid sequences revealed mainly the presence of Alphaproteobacteria belonging to Bradyrhizobium spp. and expression of nifH genes from Bradyrhizobia was detected. The nitrogenase activity evaluated by acetylene reduction assay was 0.5-7.5μmolC(2)H(4)h(-1)g(-1), comparable with early nodules of legumes associated with specific nitrogen-fixing bacteria. This is the first demonstration of nitrogenase expression gene and activity within truffle.