Cerebroside and Sulfatide Biosynthesis in the Brain of Snell Dwarf Mouse: Effects of Thyroxine and Growth Hormone in the Early Postnatal Period

Snell dwarf mice (dw/dw) and normal mice (+/?) were injected with thyroxine (T₄) (1 μg/animal, four injections) and growth hormone (GH) (20 μg/animal, four injections) from the 5th to the 15th day of life. In the untreated dw/dw mouse brain, the specific activities of UDP-galactose:ceramide galactosyltransferase (CGalT), PAPS:cerebroside sulfotransferase (CST), and 2′,3′-cyclic nucleotide 3′-phosphohydrolase (CNP) were decreased by 28, 25, and 37%, respectively, compared with the control untreated +/? mice. The major effect of T₄ was an increase of the brain CNP in the +/? mice (+40%) and dw/dw mice (+111%). The treatment with T₄ also brought to normal the level of CGalT in dw/dw brain; a somewhat less marked effect on CST was observed. The treatment with GH had a great stimulatory effect on CNP: the specific activity of this enzyme increased by 40 and 69% in +/? and dw/dw mouse brain, respectively. On the contrary, no effect of GH on the CGalT activity was observe in this study. Our results suggest that T₄ and GH may have both independent and complementary actions on the myelin-associated enzymes during the early postnatal period of brain development.     

Recombinant outer-surface protein A (des-Cys1-OspA) from the Lyme disease spirochete Borrelia burgdorferi: high production levels in Saccharomyces cerevisiae yeast cultures

The recombinant outer-surface protein A with an N-terminally truncated form (des-Cys¹-OspA) from the Lyme disease spirochete Borrelia burgdorferi was expressed in Saccharomyces cerevisiae at high production levels. Since the recombinant vaccine candidate expressed in Escherichia coli exhibits low production yields and the purification of lipoproteins appears to be difficult, we have investigated the secretion of a soluble recombinant OspA in the yeast S. cerevisiae. In this way, a Leu⁺ derivative of S. cerevisiae cI3ABYS86 was used as the host strain transformed with an expression plasmid containing the gene encoding des-Cys¹-OspA and driven by the MF1 promoter. The fed-batch culture results revealed that an efficient secretion of des-Cys¹-OspA is obtained with a high production level of about 2.1 g 1^–1 at a cell density of 101 g 1^–1 cell dry weight. The accumulation of recombinant protein in the supernatant exceeds 6% of the total yeast proteins when estimated by sodium dodecyl sulphate/polyacrylamide gel electrophoresis. Moreover, des-Cys¹-OspA showed lower solubilities at high cell densities and, as a consequence, a fraction of the recombinant protein precipitated. An internal cleavage of the MF1 pro::des-Cys¹-OspA precursor was also detected. However, in this case the cleavage occurred at a frequency such that the large amounts of the secreted des-Cys¹-OspA could be employed for the evaluation of an immunogenic effect on animal immunization. These studies will extend the knowledge of the usefulness of OspA as a vaccine for Lyme borreliosis.     

Spatial and Temporal variations of mangrove fish assemblages in Martinique (French West Indies)

A study of the mangrove fish fauna in a bay of Martinique Island (French West Indies) was carried out at different seasons during two consecutive years. fishes were sampled with specific hoop-nets in the coastal areas at 8 stations.A total of 87 species was collected in the bay. Most individuals were represented by small-size specimens and juveniles. The overall species richness varied according to the stations and the sampling periods. The biomass and number of individuals were variable according to the location but remained stable in time. A factor correspondence analysis and a hierarchical clustering with median links were used to follow the evolution of the stations in space and time. Two types of stations were differentiated: the stations characterized by the mangrove and those under the influence of seagrass beds. A seasonal cycle, opposing the dry periods to the others, was observed.Thus, it seems that the use of the mangrove habitat by the fishes is optimized through a complete reorganization of communities in terms of species composition whereas the overall number and biomass remain stable. This model remains valid even for the most constraining biota of the mangrove ecosystem inhabited by a small number of well adapted species.     

Prioritising African perspectives in psychiatric genomics research: Issues of translation and informed consent

Psychiatric genomics research with African populations comes with a range of practical challenges around translation of psychiatric genomics research concepts, procedures, and nosology. These challenges raise deep ethical issues particularly around legitimacy of informed consent, a core foundation of research ethics. Through a consideration of the constitutive function of language, the paper problematises like‐for‐like, designative translations which often involve the ‘indigenization’ of English terms or use of metaphors which misrepresent the risks and benefits of research. This paper argues that effective translation of psychiatric genomics research terminology in African contexts demands substantive engagement with African conceptual schemas and values. In developing attenuated forms of translational thinking, researchers may recognise the deeper motivational reasons behind participation in research, highlighting the possibility that such reasons may depart from the original meaning implied within informed consent forms. These translational issues might be ameliorated with a critical re‐examination of how researchers develop and present protocols to institutional ethics review boards.     

Evaluation and selection of tandem repeat loci for a Brucella MLVA typing assay

Background  

The classification of Brucella into species and biovars relies on phenotypic characteristics and sometimes raises difficulties in the interpretation of the results due to an absence of standardization of the typing reagents. In addition, the resolution of this biotyping is moderate and requires the manipulation of the living agent. More efficient DNA-based methods are needed, and this work explores the suitability of multiple locus variable number tandem repeats analysis (MLVA) for both typing and species identification.     

Phylogenetic analysis of mitochondrial LSU rRNA in oniscids

The phylogenetic relationships among oniscids (Crustacea, Isodopa) remain contradictory despite numerous morphological studies. We have investigated them using molecular data. Partial sequences of the mitochondrial LSU rRNA gene were obtained from 42 species of aquatic and terrestrial crustaceans from 31 genera. This gene provided well-supported information, notwithstanding the high taxonomic level of this study, indicating a useful amount of variation despite the noise due to multiple substitutions. The phylogenetic inferences demonstrated that a) Crinocheta and Synocheta sections are monophyletic and sister-groups, b) Ligiidae and Tylidae representatives are in a basal position compared to other oniscids, c) Helleria brevicornis, the only representative of the Helleriinae subfamily, has undergone different evolution, d) the relationships between aquatic isopods and ancient groups of Oniscidea are not resolved, probably due to fast radiation not discriminated by the molecular phylogeny.     

On-line resources for bacterial micro-evolution studies using MLVA or CRISPR typing

The control of bacterial pathogens requires the development of tools allowing the precise identification of strains at the subspecies level. It is now widely accepted that these tools will need to be DNA-based assays (in contrast to identification at the species level, where biochemical based assays are still widely used, even though very powerful 16S DNA sequence databases exist). Typing assays need to be cheap and amenable to the designing of international databases. The success of such subspecies typing tools will eventually be measured by the size of the associated reference databases accessible over the internet. Three methods have shown some potential in this direction, the so-called spoligotyping assay (Mycobacterium tuberculosis, 40,000 entries database), Multiple Loci Sequence Typing (MLST; up to a few thousands entries for the more than 20 bacterial species), and more recently Multiple Loci VNTR Analysis (MLVA; up to a few hundred entries, assays available for more than 20 pathogens). In the present report we will review the current status of the tools and resources we have developed along the past seven years to help in the setting-up or the use of MLVA assays or lately for analysing Clustered Regularly Interspaced Short Palindromic Repeats called CRISPRs which are the basis for spoligotyping assays.     

Activation of NK cell-mediated cytotoxicity by a SAP-independent receptor of the CD2 family.

Some CD2 family receptors stimulate NK cell-mediated cytotoxicity through a signaling pathway, which is dependent on the recruitment of an adapter protein called SLAM-associated protein (SAP). In this work we identify a novel leukocyte cell surface receptor of the CD2 family called CD2-like receptor activating cytotoxic cells (CRACC). CRACC is expressed on cytotoxic lymphocytes, activated B cells, and mature dendritic cells, and activates NK cell-mediated cytotoxicity. Remarkably, although CRACC displays cytoplasmic motifs similar to those recruiting SAP, CRACC-mediated cytotoxicity occurs in the absence of SAP and requires activation of extracellular signal-regulated kinases-1/2. Thus, CRACC is a unique CD2-like receptor which mediates NK cell activation through a SAP-independent extracellular signal-regulated kinase-mediated pathway.     

Wolbachia infection in crustaceans: novel hosts and potential routes for horizontal transmission

Thirty‐five percent of isopods are estimated to be infected by Wolbachia, an intracellular maternally inherited α‐Proteobacterium. Previous studies have indicated that horizontal transfer of Wolbachia strains may occur, although the mechanisms are unclear. The wsp gene was sequenced from 17 Wolbachia strains harboured by crustacean host species and three from their associated predators and parasites. Two major clades of Wolbachia were found in crustacean, with relatives also found in insects, the other restricted to crustaceans. Highly divergent Wolbachia strains were found in a woodlouse‐eating spider and its prey, suggesting no intertaxon bacterial exchange via the predator–prey route. The phylogenetic proximity of Wolbachia from parasitoid flies or phoretic mites to those from isopods suggests that horizontal symbiont transmission may have occurred between those taxa. Two distant Wolbachia strains were detected in two intertidal amphipods; these strains were closely related to different coastal isopod symbionts, suggesting Wolbachia transmission may occur between distantly related crustacean hosts living under the same ecological conditions.