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AIM: Evidence from mouse models suggests that brain serotonergic pathways control blood glucose. We hypothesized that sumatriptan (5HT1B -receptor agonist) would alter glucose homeostasis in humans. MATERIALS AND METHODS: We conducted a two-visit random-order double-blinded placebo-controlled cross-over trial in 10 overweight adults that were otherwise healthy. Participants received sumatriptan (single dose, 100 mg) or placebo before undergoing a 60-min intravenous glucose tolerance test, followed by a 120-min hyperinsulinaemic euglycaemic clamp. RESULTS: Glucose excursion was greater during intravenous glucose tolerance test with sumatriptan compared with placebo [iAUC0-60 min 316 (268-333) vs. 251 (197-319) min/mmol/L p = .047]. This was probably explained by a combination of reduced circulating insulin levels [iAUC0-10 min 1626 (1103-2733) vs. 2336 (1702-3269) min/pmol/L, p = .005], reduced insulin sensitivity [M/I-value 2.11 (1.15, 4.05) vs. 3.03 (1.14, 4.90) mg/kg/min per pmol/L, p = .010] and glucose effectiveness [SG 0.17 (0.12, 0.21) vs. 0.22 (0.18, 0.65)/min, p = .027]. CONCLUSIONS: 5HT1B receptors have a glucoregulatory role in humans, probably acting on insulin secretion, insulin sensitivity and glucose effectiveness.

The aim of this study was to examine quality of life determinants among clinical nurses in Croatia with an emphasis on their work ability. An important personnel management challenge is to explore factors that stimulate or hinder the development of individual work ability and quality of life throughout a career. Design: A cross-sectional study. The study was performed during 2007-2008 in six randomly selected hospitals in Croatia. The self-administered questionnaires included the Work Ability Index (WAI) developed by the Finnish Institute of Occupational Health, the Quality of Life questionnaire (WHOQL-BREF) developed by the World Health Organization and additional socio-demographic questions. A total number of 1212 nurses completed the questionnaires, giving a response rate of 67.3%. Binary logistic regression was performed to assess how socio-demographic characteristics and work ability groups predict each of the WHOQL-BREF domains. Having a satisfactory WAI score (WAI≥37) was significantly the most important predictor for all quality of life domains, with the odds ratios (OR) being as follows: OR=6.8 (95%CI: 4.8-9.6) for the physical domain, OR=2.3 (95%CI: 1.7-3.1) for the psychological domain, OR=1.7 (95%CI: 1.3-2.4) for the social relationship domain and OR=1.7 (95%CI: 1.3-2.3) for the environmental domain. Satisfactory work ability was a major quality of life determinant in all WHOQL-BREF domains with the highest odds ratio for the physical domain. Maintaining clinical nurses’ work ability is an important issue, because it is foundational for the quality of life of the workforce. Relevance to clinical practice. Our study provides quantified estimates of the extent to which a satisfactory WAI score predicts a better score in physical, psychosocial, social relationships and environmental domain of nurses’ quality of life. Therefore, maintaining or improving nurses’ work ability remains the essential aim of hospital managers.

In the temperate Azores carbonate factory, a substantial fraction of the calcareous skeletal components is recycled by a remarkable biodiversity of biota producing bioerosion traces (incipient trace fossils). To study this biodiversity, experimental carbonate substrates were exposed to colonisation by epilithic and endolithic organisms along a bathymetrical gradient from 0 to 500 m depth, during 1 and 2 years of exposure. The overall bioerosion ichnodiversity is very high and comprises 56 ichnotaxa and ichnoforms attributed to cyanobacteria, chlorophytes, fungi, other micro-chemotrophs, macroborers, grazers and epilithic attachment scars. In the intertidal, hydrodynamic force, partial emersion and strong temperature fluctuations lead to the lowest ichnospecies richness. This contrasts with the highest ichnodiversity found at 15 m under the most favourable environmental conditions. Towards aphotic depths, a gradual depletion in ichnodiversity is observed, most probably because of the restricted light availability and a slowdown in ichnocoenosis development. Analysis of similarity (ANOSIM), in combination with non-metrical multidimensional scaling (NMDS), was used to highlight variability in the relative abundance of traces among depths, substrate orientations and exposure times. Ichnodiversity and abundance of traces decrease significantly with depth and are higher on up-facing versus down-facing substrates, whereas differences between years were not as pronounced. This study demonstrates that statistical methods of biodiversity analysis are not per se restricted to biotaxa but may well be applied also to ichnotaxa. In the analysis of trace fossil assemblages, this approach supports the recognition of diversity patterns and their relation to environmental gradients.

To quantify the contribution of endolithic phototrophs to primary production of dead carbonate substrates, experimental blocks of cleaned Porites lobata Dana skeleton were placed at three different sites in Kaneohe Bay, Hawaii: inshore, lagoonal, and oceanic. After 6 months of exposure, experimental blocks were colonized by communities characteristic of their estuarine (inshore, lagoonal) and oceanic (ocean) environments. Blocks were subsampled; net photosynthesis (NP) and chl a concentrations of the whole blocks (epi- and endoliths) and scrapped blocks (only endoliths) were quantified. Green turf algae colonized predominantly inshore and lagoonal blocks, while encrusting corallines were the dominant epiliths colonizing oceanic blocks. Four main species of endolithic phototrophs were identified in all blocks: Mastigocoleus testarum Lagerheim, Plectonema terebrans Bornet and Flahault (cyanobacteria), Phaeophila dendroides Crouan and Crouan, and Ostreobium quekettii Bornet and Flahault (Chlorophytes). While epiliths were very different between sites, NP rates and chl a concentration of endoliths did not vary significantly and were positively correlated (191 ± 25 mmol C·m -2 ·day -1 and 590 ± 150 mg chl a · m 2 of reef, respectively). Assimilation numbers for whole communities, including both epilithic and endolithic communities, were similar to those measured for endolithic communities alone (average of 0.3 g C-g chl a·h -1 ). Under experimental conditions, the contribution of endolithic phototrophs to community NP rates of blocks ranged from 56% to 81%, and under natural conditions, we estimated that this contribution ranged between 32% and 46%. Thus, we showed that the endolithic phototrophs are one of the major primary producers in dead coral substrates in a wide range of coral reef environments.

The new allele HLA-A*01:200 differs from A*01:12 by four nucleotide substitutions in exon 3.

Natural populations of benthic cyanobacteria in the lagoon of Tikehau Atoll in French Polynesia were studied using a polyphasic approach that combined field observations, LM, culturing, and molecular sequencing. The approach assessed their phenotypic (morphotypic and ecological) and genotypic diversity. Partial sequences (approximately 450 bp long) of the PCR-amplified 16S rRNA gene were obtained from both natural and cultured populations using cyanobacteria-specific primers. The sequences obtained clustered into six separate phylogenetic clusters in relation to the complete set of 16S rRNA sequences available in public databases. Phylogenetic clustering correlated in many cases with some morphological characteristics. For example, Spirulina subsalsa could be identified to the morphospecies level using both molecular and microscopic approaches. Morphotypes identified as Symploca hydnoides (Kutz. ex Gomont) TK22, Phormidium sp. TK1, and P. laysanense (Lemmerman) TK14 formed a distinct cluster. The morphogenus Hydrocoleum (Blennothrix) clustered interestingly close to the morphologically similar, but planktonic, marine cyanobacterium Trichodesmium, suggesting a relationship. Other sequences belonging to morphotaxa with very narrow trichomes were found to be polyphyletic. Enrichment cultures, with inoculum obtained from field populations, were followed over a period of 18 months. Dominance in all cultures shifted over time in favor of a set of cyanobacterial strains with narrow trichomes, which were phenotypically and phylogenetically different from natural populations dominating the original samples. Sequences from strains enriched by cultivation clustered into two well-defined phylogenetic groups, possibly identifying new taxa. These clusters may represent a niche of opportunistic species, evolved to exploit short-term nutrient spikes in the environment.

A new species of endolithic cyanobacteria, Hyella racemus sp. nov. (order Pleurocapsales), penetrates ooid grains in actively shaling sands in shallow (0.5-5 m) waters of the Bahama carbonate platform and the Arabian Gulf. Hyella racemus is characterized by prolific branching, resulting in dense grape-like cell clusters that penetrate the carbonate substrate. The clusters radiate inward and form deep, isodiametric pits. Resin casts of these pits are framboid (raspberry-like) in shape. The borehole morphology conforms with the shape of the endolith body and can be identified in resin-cast preparations. Cell division is by cleavage with regular alternation of division planes

Two distinctive patterns of microbial destruction of mineral shell in mussels from the Florida Escarpment (3266 m water depth) are described. One pattern follows a surfacial selective removal of intercrystalline organic matrix creating caries-like pits. Pitting of the shell resembles spreading bacterial colonies and results in substantial thinning of the original shell. The second pattern consists of an extensive system of sacs with branched and tapered extensions penetrating deep into the shell. Both activities are carried out by unknown microbial agents on live mussels, as evidenced by the presence of repair nacre, which often underlies effected areas. Shell destruction is primarily biological, providing conditions for enhanced chemical dissolution of the mineral shell. Summary Damage and removal of the protective periostracum layer of deep-sea mussels by various eukaryotic and prokaryotic microorganisms (Hook & Golubic, 1988, 1990, 1992) exposes the mineral portion of the shell to microbial destruction. This biogenic destruction exceeds the rates of inorganic carbonate dissolution in the area of study. Two types of destructive agents attack the shells of live mussels. The first type forms shallow caries along the interface between periostracum and the mineral shell, primarily attacking intercrystalline organic matrix. The second type represents boring microorganisms, morphologically similar to chytrids, that penetrate and permeate the entire mineral portion of the shell. These activities significantly weaken the shell structure and increase its internal porosity.

Vacated microborings in periostracum of live mussels of the Florida Escarpment redox community (depth of 3266 m) become a habitat for a prolific secondary microbiota consisting of a variety of prokaryotic and a few eukaryotic organisms. Periostracum surface is also colonized by diverse microorganisms, dominated by presumed chemolithotrophic bacteria with stacks of intracellular lamellae. Unlike sheltered microflora within borings, the surface community is heavily grazed upon by numerous archaeogastropods and ciliates.

Hyella immanis, a new species of endolithic cyanobacterium that penetrates carbonate ooid sand grains in the Arabian/Persian Gulf, is formally described. Natural populations of the new taxon were sampled in moving ooid shoals at four locations along the east coast of Saudi Arabia, together with seven other endolithic taxa. The new species was isolated, and its properties were studied under experimental conditions. Small reproductive cells (baeocytes) exhibited positively phototactic gliding motility following release. In culture they grew into colonies forming isodiametric packages (prevalent on agar) and distinct pseudofilaments (prevalent in liquid culture). Carbonate penetration of the cultured strain in liquid culture proceeded at a rate of up to 10 μ· d−1. Agitation of cultures with magnetic stirrers enhanced the frequency of borings and the initial boring rates, but it had no effect on the continuing boring activity. A fossil counterpart of the new species was identified in Upper Proterozoic (700–800 million years old) silicified oolitic and pisolitic rocks of East Greenland.

Mussel periostracum from the Florida Escarpment redox community (3266 m depth) is extensively bored by a variety of microorganisms. Four different types of pit borings were observed and characterized on the basis of SEM images of their resin casts, and/or light and TEM reconstructions: two large, open-pit borers, a “button” borer, and a cone borer. These boring patterns represent distinctive feeding “strategies”. The cumulative activities of periostracum borers remove the protective organic layer from the mussel shells, exposing the mineral to cndolith attack.

We prepared a cosmid library from chimpanzee DNA and screened it with a mouse probe specific for the complement component 4 (C4)-encoding gene. We isolated 29 clones and constructed restriction maps for 20 of these. The clones could be arranged into two overlapping clusters covering the entire C4 region of both chromosomes in this particular heterozygous chimpanzee. The region is about 100 kilobases (kb) long and contains two C4 and two CYP21 genes, the latter coding for the enzyme 21-hydroxylase. Using oligonucleotide probes we identified the genes as corresponding to human C4A, C4B, CYP21 and CYP21P genes. The last gene apparently contains an 8-base pair (bp) deletion (as does the corresponding human gene), which renders it a pseudogene. The genes are arranged in the order C4A...CYP21P...C4B...CYP21. Each of the two C4 genes is 16 kb long and thus corresponds to the short version of the human C4 genes. We suggest that the duplication of the basic C4-CYP21 unit that generated the standard arrangement of the human C4-CYP21 region occurred before the separation of the evolutionary lineages leading to humans and chimpanzees (i.e., more than five million years ago). We suggest further that the original form of the C4 gene was of the long variety and was generated by the insertion of a 6.8-kb element into one of the C4 introns. The element was subsequently excised in the ancestors of the chimpanzees and in at least one lineage of the human C4B gene. We speculate that the presence of the 6.8-kb insert in the human C4A and some C4B genes might largely be responsible for the great instability of this chromosomal region which leads to frequent duplications and deletions, some of which cause 21-hydroxylase deficiency.