Comparative Characterization of Vibrio cholerae O1 from Five Sub-Saharan African Countries Using Various Phenotypic and Genotypic Techniques

We used standardized methodologies to characterize Vibrio cholerae O1 isolates from Guinea, Democratic Republic of the Congo (DRC), Togo, Côte d’Ivoire and Mozambique. We investigated 257 human isolates collected in 2010 to 2013. DRC isolates serotyped O1 Inaba, while isolates from other countries serotyped O1 Ogawa. All isolates were biotype El Tor and positive for cholera toxin. All isolates showed multidrug resistance but lacked ciprofloxacin resistance. Antimicrobial susceptibility profiles of isolates varied between countries. In particular, the susceptibility profile of isolates from Mozambique (East-Africa) included resistance to ceftriaxone and was distinctly different to the susceptibility profiles of isolates from countries located in West- and Central-Africa. Molecular subtyping of isolates using pulsed-field gel electrophoresis (PFGE) analysis showed a complex relationship among isolates. Some PFGE patterns were unique to particular countries and clustered by country; while other PFGE patterns were shared by isolates from multiple countries, indicating that the same genetic lineage is present in multiple countries. Our data add to a better understanding of cholera epidemiology in Africa.     

The presence of two populations of sensory-type cells in the pineal organ of the five-bearded rockling,Ciliata mustela L. (Teleostei)

The pineal organ of the five-bearded rockling, Ciliata mustela L., was examined by means of electron microscopy. Two categories of sensory cells are described: 1) Sensory cells 1 (or photoreceptor cells sensu stricto) showing the characteristic ultrastructure of photoreceptor cells with a well-developed receptor pole (outer segment) and a transmitter pole (ribbon-type synapse in the basal pedicle contacting dendritic processes), and a segmental organization of organelles. 2) Sensory cells 2 (or photoneuroendocrine cells) displaying no particular segmentation. The ultrastructure of the receptor pole (outer segment) is variable in shape (with either long or short disks) and in the number of disks; some outer segments are simple cilia of the 9 + 0 type. This second cell category is rich in smooth endoplasmic reticulum, beta-particles of glycogen, dense inclusions of variable size and content, and dense-core vesicles 130 nm in diameter. These cells have an extended contact area with the perivascular space. The functional significance of both cell categories is discussed in terms of the known physiological responses of the pineal organ. A possible confusion in identification of interstitial cells and neuroendocrine cells in some teleost species is discussed.     

Cg-TIMP, an inducible tissue inhibitor of metalloproteinase from the Pacific oyster Crassostrea gigas with a potential role in wound healing and defense mechanisms(1).

We have cloned and characterized a cDNA encoding Cg-TIMP, the first tissue inhibitor of metalloproteinase identified in mollusks. The isolated cDNA encodes a protein of 221 residues that has a domain organization similar to that of vertebrate TIMPs including a signal sequence, and the 12 cysteines characteristic of the TIMP signature. Analysis of Cg-TIMP expression in adult oyster tissues, by Northern blot and in situ hybridization, indicates that Cg-TIMP was only expressed in hemocytes which are the key components of defense mechanisms in mollusks. We also observed that Cg-TIMP mRNA accumulated during shell damage and bacterial challenge. This pattern of expression suggests that Cg-TIMP may be an important factor in wound healing and defense mechanisms.     

The Met1-linked ubiquitin machinery in inflammation and infection

Ubiquitination is an essential post-translational modification that regulates most cellular processes. The assembly of ubiquitin into polymeric chains by E3 ubiquitin ligases underlies the pleiotropic functions ubiquitin chains regulate. Ubiquitin chains assembled via the N-terminal methionine, termed Met1-linked ubiquitin chains or linear ubiquitin chains, have emerged as essential signalling scaffolds that regulate pro-inflammatory responses, anti-viral interferon responses, cell death and xenophagy of bacterial pathogens downstream of innate immune receptors. Met1-linked ubiquitin chains are exclusively assembled by the linear ubiquitin chain assembly complex, LUBAC, and are disassembled by the deubiquitinases OTULIN and CYLD. Genetic defects that perturb the regulation of Met1-linked ubiquitin chains causes severe immune-related disorders, illustrating their potent signalling capacity. Here, we review the current knowledge about the cellular machinery that conjugates, recognises, and disassembles Met1-linked ubiquitin chains, and discuss the function of this unique posttranslational modification in regulating inflammation, cell death and immunity to pathogens.Subject terms: Signal transduction, Antimicrobial responses, Cell death and immune response