Genetic diversity of the black mangrove (Avicennia germinans L.) in Colombia

This study analyzed the genetic diversity and patterns of genetic structure in Colombian populations of Avicennia germinans L. using microsatellite loci. A lower genetic diversity was found on both the Caribbean (Ho = 0.439) and the Pacific coasts (Ho = 0.277) than reported for the same species in other locations of Central American Pacific, suggesting the deterioration of genetic diversity. All the populations showed high inbreeding coefficients (0.131–0.462) indicating heterozygotes deficience. The genetic structure between the Colombian coasts separated by Central American Isthmus was high (F_RT = 0.39) and the analyses of the genetic patterns of A. germinans revealed a clear differentiation of populations and no-recent gene flow evidence between coasts. Genetic structure was found within each coast (F_ST = 0.10 for the Caribbean coast and F_ST = 0.22 for the Pacific coast). The genetic patterns along the two coasts appear to reflect a forcing by local geomorphology and marine currents. Both coasts constitute a different Evolutionary Significant Unit, so we suggest for future transplantations plans that propagules or saplings of the populations of the Caribbean coast should not be mixed with those of the Pacific Colombian coast. Besides, we suggest that reforestation efforts should carefully distinguish propagules sources within each coast.     

Identification,cloning, and functional characterization of EmrD-3, a putative multidrug efflux pump of the major facilitator superfamily from <Emphasis Type="Italic">Vibrio cholerae</Emphasis> O395

A putative multidrug efflux pump, EmrD-3, belonging to the major facilitator superfamily (MFS) of transporters and sharing homology with the Bcr/CflA subfamily, was identified in Vibrio cholerae O395. We cloned the emrD-3 gene and evaluated its role in antimicrobial efflux in a hypersensitive Escherichia coli strain. The efflux activity of this membrane protein resulted in lowering the intracellular concentration of ethidium. The recombinant plasmid carrying emrD-3 conferred enhanced resistance to several antimicrobials. Among the antimicrobials tested, the highest relative increase in minimum inhibitory concentration (MIC) of 102-fold was observed for linezolid (MIC = 256 μg/ml), followed by an 80.1-fold increase for tetraphenylphosphonium chloride (TPCL) (156.2 μg/ml), 62.5-fold for rifampin (MIC = 50 μg/ml), >30-fold for erythromycin (MIC = 50 μg/ml) and minocycline (MIC = 2 μg/ml), 20-fold for trimethoprim (MIC = 0.12 μg/ml), and 18.7-fold for chloramphenicol (MIC = 18.7 μg/ml). Among the fluorescent DNA-binding dyes, the highest relative increase in MIC of 41.7-fold was observed for ethidium bromide (125 μg/ml) followed by a 17.2-fold increase for rhodamine 6G (100 μg/ml). Thus, we demonstrate that EmrD-3 is a multidrug efflux pump of V. cholerae, the homologues of which are present in several Vibrio spp., some members of Enterobacteriaceae family, and Gram-positive Bacillus spp.     

Immune Regulatory Neural Stem/Precursor Cells Protect from Central Nervous System Autoimmunity by Restraining Dendritic Cell Function

Background

The systemic injection of neural stem/precursor cells (NPCs) provides remarkable amelioration of the clinico-pathological features of experimental autoimmune encephalomyelitis (EAE). This is dependent on the capacity of transplanted NPCs to engage concurrent mechanisms of action within specific microenvironments in vivo. Among a wide range of therapeutic actions alternative to cell replacement, neuroprotective and immune modulatory capacities of transplanted NPCs have been described. However, lacking is a detailed understanding of the mechanisms by which NPCs exert their therapeutic plasticity. This study was designed to identify the first candidate that exemplifies and sustains the immune modulatory capacity of transplanted NPCs.

Methodology/Principal Findings

To achieve the exclusive targeting of the peripheral immune system, SJL mice with PLP-induced EAE were injected subcutaneously with NPCs and the treatment commenced prior to disease onset. NPC-injected EAE mice showed significant clinical improvement, as compared to controls. Exogenous NPCs lacking the expression of major neural antigens were reliably (and for long-term) found at the level of draining lymph nodes, while establishing sophisticated anatomical interactions with lymph node cells. Importantly, injected NPCs were never found in organs other than lymph nodes, including the brain and the spinal cord. Draining lymph nodes from transplanted mice showed focal up-regulation of major developmental stem cell regulators, such as BMP-4, Noggin and Sonic hedgehog. In lymph nodes, injected NPCs hampered the activation of myeloid dendritic cells (DCs) and steadily restrained the expansion of antigen-specific encephalitogenic T cells. Both ex vivo and in vitro experiments identified a novel highly NPC-specific–BMP-4-dependent–mechanism hindering the DC maturation.

Conclusion/Significance

The study described herein, identifies the first member of the TGF β/BMP family of stem cell regulators as a novel tolerogenic factor released by NPCs. Full exploitation of this pathway as an efficient tool for vaccination therapy in autoimmune inflammatory conditions is underway.     

Endemic flora biodiversity in the south of the Iberian Peninsula: altitudinal distribution,life forms and dispersal modes

The south of the Iberian Peninsula, with an altitudinal range varying from sea level to 3482m and annual average rainfall ranging from 206 to 2223mm, has 516 vascular endemic species or subspecies, that is, an endemicity rate of 13%. This survey deals with parameters such as species richness, originality, life forms and dispersal modes of these plants, in relation to altitudinal and rainfall gradients. Although most of the endemic plants occur between 600 and 1400m a.s.l. and in the range of 600–1000mm annual average rainfall, floristic originality (rate of endemic taxa per area unit) increases exponentially with altitude. The biological spectrum of this endemic flora does not follow the usual patterns observed either in local floras in the south of the Iberian Peninsula or in other regions of the Mediterranean Basin. Chamaephytes (46.08%) and hemicryptophytes (31.37%) are very abundant, whereas therophytes (11.96%) and phanerophytes (0.98%) are comparatively rare. There is a statistically significant correlation between life form and both altitudinal and rainfall gradients. Chamaephytes reach their highest density rates within 1400–2000m a.s.l., but these records tend to decrease as rainfall rates increase. Abundance of hemicryptophytes is directly dependent on rainfall rates and inversely dependent on temperature. The altitudinal distribution pattern of therophytes is opposite to that of hemicryptophytes, but there is no clear correlation as far as rainfall gradient is concerned. Considering both the endemic plants as a whole and each of the life form groups, the relationships between the dispersal modes used and the altitudinal and rainfall gradients are analysed. Up to 44.51% of the endemic plants do not present evident adaptations to promote the dispersion of their diaspores. However, only in the group of therophytes, whose occurrence is positively related to areas of minor altitude, does this difficulty of dispersion play a significant role in the maintenance of stenochory.     

The CAPN10 gene is associated with insulin resistance phenotypes in the Spanish population

Cardiovascular disease is the leading cause of morbidity and mortality in the industrialized world. Familial aggregation of cardiovascular risk factors is a frequent finding, but genetic factors affecting its presentation are still poorly understood. The calpain 10 gene (CAPN10) has been associated with type 2 diabetes (T2DM), a complex metabolic disorder with increased risk of cardiovascular disease. Moreover, the CAPN10 gene has been associated with the presence of metabolic syndrome (MS) in T2DM and in polycystic ovary syndrome (PCOS). In this work, we have analysed whether the polymorphisms UCSNP44, -43, -19 and -63 are related to several cardiovascular risk factors in the context of MS. Molecular analysis of CAPN10 gene was performed in 899 individuals randomly chosen from a cross-sectional population-based epidemiological survey. We have found that CAPN10 gene in our population is mainly associated with two indicators of the presence of insulin resistance: glucose levels two hours after a 75-g oral glucose tolerance test (OGTT) and HOMA values, although cholesterol levels and blood pressure values are also influenced by CAPN10 variants. In addition, the 1221/1121 haplogenotype is under-represented in individuals that fulfil the International Diabetes Federation (IDF) diagnostic criteria for MS. Our results suggest that CAPN10 gene is associated with insulin resistance phenotypes in the Spanish population.     

Isodars unveil asymmetric effects on habitat use caused by competition between two endangered species

In order for competing species to coexist, segregation on some ecological niche component is required and is often mediated by differential habitat use. When unequal competitors are involved, the dominant species tends to displace the subordinate one to its less preferred habitat. Here, we use habitat isodars, an approach which reflects evolutionary stable strategies of habitat selection, to evaluate whether interspecific competition between two competing species with distinct habitat preferences, the little bustard Tetrax tetrax and the great bustard Otis tarda, modulates their habitat use. Field data on these endangered species demonstrate that unequal competitors can coexist without completely segregating on their preferred habitats. The negatively sloped isodar of the subordinate little bustard unveils its competition with the dominant great bustard. Interference from great bustards in secondary cereal habitats reinforces use of preferred natural habitat by little bustards. Studies of density‐dependent habitat selection by a single‐species can thus aid in identifying the effects of competition on community composition, and guide the conservation of at‐risk species. Isodars, in particular, represent a promising method to gain clear knowledge on interspecific competition for species in which experimental manipulations are not feasible.     

Solution conformation and dynamics of a tetrasaccharide related to the LewisX antigen deduced by NMR relaxation measurements

¹H-NMR cross-relaxation rates and nonselectivelongitudinal relaxation times have been obtained at two magnetic fields (7.0and 11.8 T) and at a variety of temperatures for the branchedtetrasaccharide methyl3-O--N-acetyl-galactosaminyl--galactopyranosyl-(14)[3-O--fucosyl]-glucopyranoside (1), an inhibitor of astrocyte growth. Inaddition, ¹³C-NMR relaxation data have also been recorded atboth fields. The ¹H-NMR relaxation data have been interpretedusing different motional models to obtain proton–proton correlationtimes. The results indicate that the GalNAc and Fuc rings display moreextensive local motion than the two inner Glc and Gal moieties, since thosepresent significantly shorter local correlation times. The¹³C-NMR relaxation parameters have been interpreted in termsof the Lipari–Szabo model-free approach. Thus, order parameters andinternal motion correlation times have been deduced. As obtained for the¹H-NMR relaxation data, the two outer residues possess smallerorder parameters than the two inner rings. Internal correlation times are inthe order of 100 ps. The hydroxymethyl groups have also different behaviour,with the exocyclic carbon on the glucopyranoside unit showing the highestS². Molecular dynamics simulations using a solvated systemhave also been performed and internal motion correlation functions have beendeduced from these calculations. Order parameters and interproton distanceshave been compared to those inferred from the NMR measurements. The obtainedresults are in fair agreement with the experimental data.     

Localization and Properties of Enzymes Involved with Electron Transport Activity in Mycobacteria

A study of the subcellular localization of the nicotinamide adenine dinucleotide (NADH)-3-(4, 3-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT) oxido-reductase systems in Mycobacterium was presented. Evidence based on starch gel electrophoresis and different responses of the subcellular fractions to heat inactivation suggested the existence of more than one enzyme responsible for the NADH-MTT oxido-reductase activity. One type of activity was found in the membrane-mesosome fraction which contained labile and electrophoretically non-migrating enzymes. Another type of activity was also detected in the soluble fraction which on starch gel electrophoresis exhibited 4 bands of activity, two of which showed heat resistance.     

Oral Candida colonization in patients with chronic periodontitis. Is there any relationship?

Background

Candida can be implicated in the pathology of chronic periodontitis.