The Pattern of Change in the Abundances of Specific Bacterioplankton Groups Is Consistent across Different Nutrient-Enriched Habitats in Crete

A common source of disturbance for coastal aquatic habitats is nutrient enrichment through anthropogenic activities. Although the water column bacterioplankton communities in these environments have been characterized in some cases, changes in α-diversity and/or the abundances of specific taxonomic groups across enriched habitats remain unclear. Here, we investigated the bacterial community changes at three different nutrient-enriched and adjacent undisturbed habitats along the north coast of Crete, Greece: a fish farm, a closed bay within a town with low water renewal rates, and a city port where the level of nutrient enrichment and the trophic status of the habitat were different. Even though changes in α-diversity were different at each site, we observed across the sites a common change pattern accounting for most of the community variation for five of the most abundant bacterial groups: a decrease in the abundance of the Pelagibacteraceae and SAR86 and an increase in the abundance of the Alteromonadaceae, Rhodobacteraceae, and Cryomorphaceae in the impacted sites. The abundances of the groups that increased and decreased in the impacted sites were significantly correlated (positively and negatively, respectively) with the total heterotrophic bacterial counts and the concentrations of dissolved organic carbon and/or dissolved nitrogen and chlorophyll α, indicating that the common change pattern was associated with nutrient enrichment. Our results provide an in situ indication concerning the association of specific bacterioplankton groups with nutrient enrichment. These groups could potentially be used as indicators for nutrient enrichment if the pattern is confirmed over a broader spatial and temporal scale by future studies.     

Analysis of a zebrafish behavioral mutant reveals a dominant mutation in atp2a1/SERCA1

Zebrafish embryos demonstrate robust swimming behavior, which consists of smooth, alternating body bends. In contrast, several motility mutants have been identified that perform sustained, bilateral trunk muscle contractions which result in abnormal body shortening. Unlike most of these mutants, accordion (acc)^dta5 demonstrates a semidominant effect: Heterozygotes exhibit a distinct but less severe phenotype than homozygotes. Using molecular‐genetic mapping and candidate gene analysis, we determined that acc^dta5 mutants harbor a novel mutation in atp2a1, which encodes SERCA1, a calcium pump important for muscle relaxation. Previous studies have shown that eight other acc alleles compromise SERCA1 function, but these alleles were all reported to be recessive. Quantitative behavioral assays, complementation testing, and analysis of molecular models all indicate that the acc^dta5 mutation diminishes SERCA1 function to a greater degree than other acc alleles through either haploinsufficient or dominant‐negative molecular mechanisms. Since mutation of human ATP2A1 results in Brody disease, an exercise‐induced impairment of muscle relaxation, acc^dta5 mutants may provide a particularly sensitive model of this disorder. genesis, 48:354–361, 2010. © 2010 Wiley‐Liss, Inc.     

Bacterial Community Composition in Different Sediments from the Eastern Mediterranean Sea: a Comparison of Four 16S Ribosomal DNA Clone Libraries

The regional variability of sediment bacterial community composition and diversity was studied by comparative analysis of four large 16S ribosomal DNA (rDNA) clone libraries from sediments in different regions of the Eastern Mediterranean Sea (Thermaikos Gulf, Cretan Sea, and South lonian Sea). Amplified rDNA restriction analysis of 664 clones from the libraries indicate that the rDNA richness and evenness was high: for example, a near-1:1 relationship among screened clones and number of unique restriction patterns when up to 190 clones were screened for each library. Phylogenetic analysis of 207 bacterial 16S rDNA sequences from the sediment libraries demonstrated that Gamma-, Delta-, and Alphaproteobacteria, Holophaga/Acidobacteria, Planctomycetales, Actinobacteria, Bacteroidetes, and Verrucomicrobia were represented in all four libraries. A few clones also grouped with the Betaproteobacteria, Nitrospirae, Spirochaetales, Chlamydiae, Firmicutes, and candidate division OPl 1. The abundance of sequences affiliated with Gammaproteobacteria was higher in libraries from shallow sediments in the Thermaikos Gulf (30 m) and the Cretan Sea (100 m) compared to the deeper South Ionian station (2790 m). Most sequences in the four sediment libraries clustered with uncultured 16S rDNA phylotypes from marine habitats, and many of the closest matches were clones from hydrocarbon seeps, benzene-mineralizing consortia, sulfate reducers, sulk oxidizers, and ammonia oxidizers. LIBSHUFF statistics of 16S rDNA gene sequences from the four libraries revealed major differences, indicating either a very high richness in the sediment bacterial communities or considerable variability in bacterial community composition among regions, or both.     

An Extended Active-site Motif Controls the Reactivity of the Thioredoxin Fold

Proteins belonging to the thioredoxin (Trx) superfamily are abundant in all organisms. They share the same structural features, arranged in a seemingly simple fold, but they perform a multitude of functions in oxidative protein folding and electron transfer pathways. We use the C-terminal domain of the unique transmembrane reductant conductor DsbD as a model for an in-depth analysis of the factors controlling the reactivity of the Trx fold. We employ NMR spectroscopy, x-ray crystallography, mutagenesis, in vivo functional experiments applied to DsbD, and a comparative sequence analysis of Trx-fold proteins to determine the effect of residues in the vicinity of the active site on the ionization of the key nucleophilic cysteine of the -CXXC- motif. We show that the function and reactivity of Trx-fold proteins depend critically on the electrostatic features imposed by an extended active-site motif.     

Urotensin-II System in Genetic Control of Blood Pressure and Renal Function

Urotensin-II controls ion/water homeostasis in fish and vascular tone in rodents. We hypothesised that common genetic variants in urotensin-II pathway genes are associated with human blood pressure or renal function. We performed family-based analysis of association between blood pressure, glomerular filtration and genes of the urotensin-II pathway (urotensin-II, urotensin-II related peptide, urotensin-II receptor) saturated with 28 tagging single nucleotide polymorphisms in 2024 individuals from 520 families; followed by an independent replication in 420 families and 7545 unrelated subjects. The expression studies of the urotensin-II pathway were carried out in 97 human kidneys. Phylogenetic evolutionary analysis was conducted in 17 vertebrate species. One single nucleotide polymorphism (rs531485 in urotensin-II gene) was associated with adjusted estimated glomerular filtration rate in the discovery cohort (p = 0.0005). It showed no association with estimated glomerular filtration rate in the combined replication resource of 8724 subjects from 6 populations. Expression of urotensin-II and its receptor showed strong linear correlation (r = 0.86, p<0.0001). There was no difference in renal expression of urotensin-II system between hypertensive and normotensive subjects. Evolutionary analysis revealed accumulation of mutations in urotensin-II since the divergence of primates and weaker conservation of urotensin-II receptor in primates than in lower vertebrates. Our data suggest that urotensin-II system genes are unlikely to play a major role in genetic control of human blood pressure or renal function. The signatures of evolutionary forces acting on urotensin-II system indicate that it may have evolved towards loss of function since the divergence of primates.     

Serum lipid levels and bone mineral density in Greek postmenopausal women

Contradictory results have been reported regarding a relationship between serum lipid levels and bone mineral density. The purpose of this study was to further investigate a possible relationship between those parameters in Greek postmenopausal women. A total of 591 patients followed at a tertiary hospital were examined for seven different lipid factors in relation to dual-emission X-ray absorptiometry measurements at the lumbar spine. Lipoprotein-a was the only lipid measurement that univariately showed an almost significant trend of association with bone mass category (analysis of variance [ANOVA] p value 0.062 for Ln(Lipoprotein-a)). In multiple regression, it was noted that a non-significant negative trend of association of high density lipoprotein (HDL) cholesterol and Apolipoprotein AI with lumbar T-score (p value 0.058 and 0.075, respectively). In age subgroup analysis, Lipoprotein-a and Ln(Lipoprotein-a) presented a negative correlation with lumbar T-score for women with age ≥ 53 years (p value 0.043 and 0.070, respectively), while a negative correlation of HDL and Apolipoprotein AI levels with lumbar T-score remained in women with age < 53 years (p value 0.039 and 0.052, respectively). The findings do not support a strong relationship between lipid levels and bone mass measurements.     

Hyaluronan and its binding proteins in the epithelium and intraluminal fluid of the bovine oviduct

Hyaluronan (HA) is involved in several important steps of sperm storage and of fertilization. This study investigates the presence and concentration of HA in oviductal fluid (ODF), together with the localization of HA and the presence of hyaluronan-binding proteins (HABPs) in the oviductal epithelium of normally cycling dairy heifers and cows. The concentration and amount of HA in ODF, collected over the course of several oestrous cycles via catheters placed in the isthmic and ampullar tubal segments, were measured using an ELISA. The concentration and amount of HA in ODF did not vary significantly between these anatomical regions, nor between the stages of the oestrous cycle (p > 0.05), although the amount of HA seemed to peak during oestrous. The most HA per day (2.9 +/- 0.64 microg, least square mean +/- SEM) was produced on the day of ovulation, whereas the lowest amount (1.25 +/- 0.68 microg) was produced 4 days before ovulation. To investigate the localization of HA, tissue samples were retrieved at well-defined stages of the oestrous cycle and from corresponding regions of the oviduct. Sections and protein extracts from the tissue samples were studied histochemically using biotinylated HABP and immunoblotted with fluorescein isothiocyanate (FITC)-HA, respectively. Presence of HA labelling in the oviductal epithelium was restricted to the sperm reservoir, a localization that seemed to be cycle-independent. The immunoblotting of samples from the lining epithelium revealed seven bands of HABPs. We confirm that the bovine oviduct produces HA and its binding proteins, and that HA is mainly localized to the epithelium of the sperm reservoir.     

Full genome sequencing and genetic characterization of Eubenangee viruses identify Pata virus as a distinct species within the genus Orbivirus

Eubenangee virus has previously been identified as the cause of Tammar sudden death syndrome (TSDS). Eubenangee virus (EUBV), Tilligery virus (TILV), Pata virus (PATAV) and Ngoupe virus (NGOV) are currently all classified within the Eubenangee virus species of the genus Orbivirus, family Reoviridae. Full genome sequencing confirmed that EUBV and TILV (both of which are from Australia) show high levels of aa sequence identity (>92%) in the conserved polymerase VP1(Pol), sub-core VP3(T2) and outer core VP7(T13) proteins, and are therefore appropriately classified within the same virus species. However, they show much lower amino acid (aa) identity levels in their larger outer-capsid protein VP2 (<53%), consistent with membership of two different serotypes - EUBV-1 and EUBV-2 (respectively). In contrast PATAV showed significantly lower levels of aa sequence identity with either EUBV or TILV (with <71% in VP1(Pol) and VP3(T2), and <57% aa identity in VP7(T13)) consistent with membership of a distinct virus species. A proposal has therefore been sent to the Reoviridae Study Group of ICTV to recognise 'Pata virus' as a new Orbivirus species, with the PATAV isolate as serotype 1 (PATAV-1). Amongst the other orbiviruses, PATAV shows closest relationships to Epizootic Haemorrhagic Disease virus (EHDV), with 80.7%, 72.4% and 66.9% aa identity in VP3(T2), VP1(Pol), and VP7(T13) respectively. Although Ngoupe virus was not available for these studies, like PATAV it was isolated in Central Africa, and therefore seems likely to also belong to the new species, possibly as a distinct 'type'. The data presented will facilitate diagnostic assay design and the identification of additional isolates of these viruses.