Fusogenic domains in herpes simplex virus type 1 glycoprotein H

Infection of eukaryotic cells by enveloped viruses requires fusion between the viral envelope and the cellular plasma or endosomal membrane. The actual merging of the two membranes is mediated by viral envelope glycoproteins, which generally contain a highly hydrophobic region termed the fusion peptide. The entry of herpesviruses is mediated by three conserved proteins: glycoproteins B, H (gH), and L. However, how fusion is executed remains unknown. Herpes simplex virus type 1 gH exhibits features typical of viral fusion glycoproteins, and its ectodomain seems to contain a putative internal fusion peptide. Here, we have identified additional internal segments able to interact with membranes and to induce membrane fusion of large unilamellar vesicles. We have applied the hydrophobicity-at-interface scale proposed by Wimley and White (Wimley, W. C., and White, S. H. (1996) Nat. Struct. Biol. 3, 842-848) to identify six hydrophobic stretches within gH with a tendency to partition into the membrane interface, and four of them were able to induce membrane fusion. Experiments in which equimolar mixtures of gH peptides were used indicated that different fusogenic regions may act in a synergistic way. The functional and structural characterization of these segments suggests that herpes simplex virus type 1 gH possesses several fusogenic internal peptides that could participate in the actual fusion event.     

Evaluation of various cardiovascular parameters during the intravenous administration of ranitidine

In this paper we evaluated whether a block of cardiac H2 histamine receptors by ranetidine could modify some non-invasive indices of cardiac function: PEP/LVET, heart rate, blood pressure. Five healthy volunteers underwent studies in baseline conditions and 5, 10, 15, 30, 45 minutes following i.v. injections of 1, 5 m/g Kg of ranitidine. None of the studied parameters showed any significant variation at the various time intervals. Ranetidine does not appear to alter the cardiovascular function at the dose we used.     

Adipocytes IGFBP‐2 Expression in Prepubertal Obese Children

Aims of the study were to measure insulin‐like growth factor‐binding protein‐2 (IGFBP‐2) expression by abdominal subcutaneous adipocytes and to assess the relationship between IGFBP‐2 expression, circulating IGFBP‐2, obesity, and insulin sensitivity in obese children. Thirty‐eight obese children were recruited. Insulin sensitivity was assessed by intravenous glucose tolerance test and body composition by total‐body dual‐energy X‐ray absorptiometry. Serum free and total IGF‐I, IGFBP‐2, adiponectin, and leptin were measured. Relative quantification of IGFBP‐2 mRNA by subcutaneous adipose tissue biopsies was obtained using real‐time PCR. Circulating IGFBP‐2 was positively associated with insulin sensitivity, in agreement with previous studies. IGFBP‐2 expression was associated with fat mass percentage (r = 0.656; P < 0.02), insulin sensitivity (r = ?0.604; P < 0.05), free IGF‐I (r = 0.646; P < 0.05), and leptin (r = 0.603; P < 0.05), but not with circulating IGFBP‐2 (r = 0.003, P = ns). The association between IGFBP‐2 expression and adiposity (r = 0.648; P < 0.05) was independent of insulin sensitivity (covariate). In conclusion, circulating IGFBP‐2 was positively associated with insulin sensitivity. IGFBP‐2 was expressed by subcutaneous abdominal adipocytes of obese children and increased with adiposity, independently from the level of insulin sensitivity. IGFBP‐2 expression may potentially be one of the local mechanisms used by adipocytes to limit further fat gain.     

Comparative evaluation of the effects of intravenous administration of cimetidine and ranitidine on several cardiovascular parameters

We have compared the effects of intravenous administration of cimetidine and ranetidine on some cardiovascular parameters. Five healthy volunteers received both cimetidine (3, 5 mg/Kg) and ranetidine (1, 5 mg/Kg). Heart rate, blood pressure and PEP/LVET were recorded at baseline and 5, 10, 30, 45 minutes after administration of both drugs. Intravenous administration of cimetidine and ranetidine did not induce any significant alterations in cardiovascular variables.     

Regulation of plant cell wall stiffness by mechanical stress: a mesoscale physical model

Journal of Mathematical Biology - A crucial question in developmental biology is how cell growth is coordinated in living tissue to generate complex and reproducible shapes. We address this issue...     

Antifungals,arthropods and antifungal resistance prevention: lessons from ecological interactions

Arthropods can produce a wide range of antifungal compounds, including specialist proteins, cuticular products, venoms and haemolymphs. In spite of this, many arthropod taxa, particularly eusocial insects, make use of additional antifungal compounds derived from their mutualistic association with microbes. Because multiple taxa have evolved such mutualisms, it must be assumed that, under certain ecological circumstances, natural selection has favoured them over those relying upon endogenous antifungal compound production. Further, such associations have been shown to persist versus specific pathogenic fungal antagonists for more than 50 million years, suggesting that compounds employed have retained efficacy in spite of the pathogens'' capacity to develop resistance. We provide a brief overview of antifungal compounds in the arthropods’ armoury, proposing a conceptual model to suggest why their use remains so successful. Fundamental concepts embedded within such a model may suggest strategies by which to reduce the rise of antifungal resistance within the clinical milieu.     

Plant teratologies as a result of phytoplasma infections

The direct correlation between teratological cases and phytoplasma infections was ascertained in spontaneous and cultivated plant species. Plants, belonging to 31 species and 12 families, showing symptoms of growth abnormalities were collected and analysed. Attempted detection of Rhodococcus fascians by isolation, PCR indexing and 16S rRNA sequencing from fasciated tissues allowed to exclude its presence. Nested PCR by universal primers and 16S rRNA sequence analyses indicated the presence of phytoplasmas, belonging to six groups, in the 44% of symptomatic samples. Among the infected species, Austrocylindropuntia exaltata, Opuntia subulata, Euphorbia characias, Euphorbia dendroides, Euphorbia linifolia, Euphorbia myrsinites, Rumex buchephalophorus, Linaria multicaulis and Fedia cornucopiae represent new phytoplasma hosts world-wide. Moreover this is the first report of phytoplasma belonging to subgroup 16SrRNA II-I in Italy. These findings together with the known erratic distribution in plant tissues of these phloem-restricted prokaryotes indicate a close correlation between fasciation and similar growth disorders and phytoplasma infections.     

Involvement of etfA gene during CaCO3 precipitation in Bacillus subtilis biofilm

The eftA gene in Bacillus subtilis has been suggested to be involved in the oxidation/reduction reactions during fatty acid metabolism. Interestingly etfA deletion in B. subtilis results in impairment in CaCO₃ precipitation on the biofilm. Comparisons between the wild type B. subtilis 168 and its etfA mutant during in vitro CaCO₃ crystal precipitation (calcite) revealed changes in phospholipids membrane composition with accumulation of up to 10% of anteiso-C_17:0 and 11% iso-C_17:0 long fatty acids. Ca²⁺ nucleation sites such as dipicolinic acid and teichoic acids seem to contribute to the CaCO₃ precipitation. etfA mutant strain showed up to 40% less dipicolinic acid accumulation compared with B. subtilis 168, while a B. subtilis mutant impaired in teichoic acids synthesis was unable to precipitate CaCO₃. In addition, B. subtilis etfA mutant exhibited acidity production leading to atypical flagella formation and inducing extensive lateral growth on the biofilm when grown on 1.4% agar. From the ecological point of view, this study shows a number of physiological aspects that are involved in CaCO₃ organomineralization on biofilms.     

A Phylogenetic Analysis of Human Syntenies Revealed by Chromosome Painting in Euarchontoglires Orders

To search for cytogenetic signatures that can help to clarify evolutionary affinities among the five orders within the Euarchontoglires clade, we focused on associations of conserved syntenic blocks that have been accumulated in the karyotypes of Primates (Strepsirhini and Haplorhini), five families of Rodentia, Scandentia (Tupaia belangeri), Dermoptera (Galeopterus variegatus) and Lagomorpha (Oryctolagus cuniculus). We examined available chromosome painting data to identify conserved chromosomes and chromosomal segments, and syntenic associations likely to have characterized the ancestral eutherian karyotype. The data set includes 161 characters that have been subjected to a concatenated analysis using maximum parsimony (MP) and Bayesian inference (BI). The phylogenetic pattern recovered is generally consistent with reconstructions based on molecular and morphological data (particularly with respect to higher systematic groupings), but there are several anomalies (e.g., in the position of the lagomorphs). Both MP and BI topologies have weak statistical support, as a consequence of the high number of autapomorphic and homoplastic character states that have evolved during the history of the clade. The vast majority of derived associations are located on the terminal portions of the branches, and very few can be identified to support deeper divergences in the tree, indicating that chromosomal structures are far more fluid that was previously recognized. The high levels of homoplasy reflected in our data suggest that the number of possible syntenic character states is limited by chromosomal structures, and the same associations occur repeatedly.