Peptides derived from the third cytoplasmatic loop of serotonin 1B receptor subtype selectively inhibit serotonin signal transduction via a homologous receptor

The third intracellular loops of hormonal receptors play the main role in the interaction of majority of the serpentine type receptors with heterotrimeric G-proteins. In recent years, it was shown that synthetic peptides corresponding to membrane-proximal regions of these loops could be selectively influenced with hormonal signal transduction via the receptors homologous to them and trigger signalling cascade in absence of the hormone. For the first time, we succeeded in synthesizing the peptides derived from C-terminal region of the third intracellular loop of the IB-subtype serotonin receptor and studied their influence on serotonin-sensitive adenylyl cyclase system in the rat brain. The peptides 300-316 and 306-316 (the numbers correspond to amino acid positions in the rat IB-subtype serotonin receptor) at micromolar concentrations in absence of hormone-stimulated GTP-binding of Gi,-proteins coupled with the IB-subtype serotonin receptors and inhibited forskolin-stimulated adenylyl cyclase activity. Using selective agonists and antagonists of serotonin receptors it was shown that the peptides 300-316 and 306--316 inhibited serotonin signal transduction via homologous to them receptor and weakly influenced other types of serotonin receptors. The peptide 300-316 is more active compared with its shorter analogue 306-316 in the selectivity and efficiency of action on adenylyl cyclase signalling system regulated via the IB-subtype serotonin receptors. These findings indicate that the regions 300-316 of the IB-subtype serotonin receptor are involved in interaction with Grproteins and consist of the main molecular determinants responsible for serotonin signal transduction to adenylyl cyclase.     

Phylogenetic and Metabolic Diversity of Planctomycetes from Anaerobic, Sulfide- and Sulfur-Rich Zodletone Spring, Oklahoma

We investigated the phylogenetic diversity and metabolic capabilities of members of the phylum Planctomycetes in the anaerobic, sulfide-saturated sediments of a mesophilic spring (Zodletone Spring) in southwestern Oklahoma. Culture-independent analyses of 16S rRNA gene sequences generated using Planctomycetes-biased primer pairs suggested that an extremely diverse community of Planctomycetes is present at the spring. Although sequences that are phylogenetically affiliated with cultured heterotrophic Planctomycetes were identified, the majority of the sequences belonged to several globally distributed, as-yet-uncultured Planctomycetes lineages. Using complex organic media (aqueous extracts of the spring sediments and rumen fluid), we isolated two novel strains that belonged to the Pirellula-Rhodopirellula-Blastopirellula clade within the Planctomycetes. The two strains had identical 16S rRNA gene sequences, and their closest relatives were isolates from Kiel Fjord (Germany), Keauhou Beach (HI), a marine aquarium, and tissues of marine organisms (Aplysina sp. sponges and postlarvae of the giant tiger prawn Penaeus monodon). The closest recognized cultured relative of strain Zi62 was Blastopirellula marina (93.9% sequence similarity). Detailed characterization of strain Zi62 revealed its ability to reduce elemental sulfur to sulfide under anaerobic conditions, as well as its ability to produce acids from sugars; both characteristics may potentially allow strain Zi62 to survive and grow in the anaerobic, sulfide- and sulfur-rich environment at the spring source. Overall, this work indicates that anaerobic metabolic abilities are widely distributed among all major Planctomycetes lineages and suggests carbohydrate fermentation and sulfur reduction as possible mechanisms employed by heterotrophic Planctomycetes for growth and survival under anaerobic conditions.     

Patterns and Determinants of Halophilic Archaea (Class Halobacteria) Diversity in Tunisian Endorheic Salt Lakes and Sebkhet Systems

We examined the diversity and community structure of members of the halophilic Archaea (class Halobacteria) in samples from central and southern Tunisian endorheic salt lakes and sebkhet (also known as sebkha) systems using targeted 16S rRNA gene diversity survey and quantitative PCR (qPCR) approaches. Twenty-three different samples from four distinct locations exhibiting a wide range of salinities (2% to 37%) and physical characteristics (water, salt crust, sediment, and biofilm) were examined. A total of 4,759 operational taxonomic units at the 0.03 (species-level) cutoff (OTU_0.03s) belonging to 45 currently recognized genera were identified, with 8 to 43 genera (average, 30) identified per sample. In spite of the large number of genera detected per sample, only a limited number (i.e., 2 to 16) usually constituted the majority (≥80%) of encountered sequences. Halobacteria diversity showed a strong negative correlation to salinity (Pearson correlation coefficient = −0.92), and community structure analysis identified salinity, rather than the location or physical characteristics of the sample, as the most important factor shaping the Halobacteria community structure. The relative abundance of genera capable of biosynthesis of the compatible solute(s) trehalose or 2-sulfotrehalose decreased with increasing salinities (Pearson correlation coefficient = −0.80). Indeed, qPCR analysis demonstrated that the Halobacteria otsB (trehalose-6-phosphatase)/16S rRNA gene ratio decreases with increasing salinities (Pearson correlation coefficient = −0.87). The results highlight patterns and determinants of Halobacteria diversity at a previously unexplored ecosystem and indicate that genera lacking trehalose biosynthetic capabilities are more adapted to growth in and colonization of hypersaline (>25% salt) ecosystems than trehalose producers.     

Hormonal, follicular and endometrial dynamics in letrozole-treated versus natural cycles in patients undergoing controlled ovarian stimulation

Background

To investigate the effect of pelvic floor Neuromuscular Electrical Stimulation (NMES) Therapy in improving endometrial thickness in women with thin endometrium.

Methods

41 patients undergoing assisted reproduction with a thin endometrium (less than or equal to7 mm) were recruited and advised to go for a pelvic floor NMES in frozen-thawed embryo transfer cycle. PHENIX Neuromuscular Electrical Stimulation Therapy System was used according to the manufacturer's recommended protocol for 20 to 30 minutes of intermittent vaginal electrical stimulation on the treatment days.

Results

A total of 20 and 21 were included in the NMES and non-NMES groups respectively. 12 out of 20 (60%) patients developed endometrial thickness equal to or more than 8 mm after the NMES therapy, which was the primary outcome. The mean thickness of endometrium before and after was respectively 5.60 mm (0.82 mm) and 7.93 mm (1.42 mm) in the therapy group versus 5.50 mm (1.00) and 6.78 mm (0.47) in the control group; the difference was statistically significant (P = 0.002). There was higher pregnancy rate in the NMES group (42% versus 35%) but the difference was not statistically significant.

Conclusion

Neuromuscular Electrical stimulation therapy may be effective for the patients with a thin endometrium. Further studies are needed to investigate its effectiveness.     

Importance of 3-hydroxy fatty acid composition of lipopeptides for biosurfactant activity

Biosurfactant production may be an economic approach to improving oil recovery. To obtain candidates most suitable for oil recovery, 207 strains, mostly belonging to the genus Bacillus, were tested for growth and biosurfactant production in medium with 5% NaCl under aerobic and anaerobic conditions. All strains grew aerobically with 5% NaCl, and 147 strains produced a biosurfactant. Thirty-five strains grew anaerobically with 5% NaCl, and two produced a biosurfactant. In order to relate structural differences to activity, eight lipopeptide biosurfactants with different specific activities produced by various Bacillus species were purified by a new protocol. The amino acid compositions of the eight lipopeptides were the same (Glu/Gln:Asp/Asn:Val:Leu, 1:1:1:4), but the fatty acid compositions differed. Multiple regression analysis showed that the specific biosurfactant activity depended on the ratios of both iso to normal even-numbered fatty acids and anteiso to iso odd-numbered fatty acids. A multiple regression model accurately predicted the specific biosurfactant activities of four newly purified biosurfactants (r2= 0.91). The fatty acid composition of the biosurfactant produced by Bacillus subtilis subsp. subtilis strain T89-42 was altered by the addition of branched-chain amino acids to the growth medium. The specific activities of biosurfactants produced in cultures with different amino acid additions were accurately predicted by the multiple regression model derived from the fatty acid compositions (r2= 0.95). Our work shows that many strains of Bacillus mojavensis and Bacillus subtilis produce biosurfactants and that the fatty acid composition is important for biosurfactant activity.     

Influence of interleukin-2 and interferon-gamma in murine schistosomiasis

Schistosoma mansoni-infected mice were administered at the time of parasite residency in the lung with recombinant murine interleukin (IL)-2 or interferon-gamma (IFN-gamma), to evaluate the impact of cytokines in host responses to primary schistosomiasis. S. mansoni lung-stage schistosomula did not affect plasma lipids levels in BALB/c, while elicited significant (p<0.05) increase in free fatty acids (FA) and decrease in cholesterol plasma levels in C57BL/6 and CD1 mice, and stimulated expression of mRNA for Th2 cytokines in BALB/c and Th1 cytokines in C57BL/6 and CD1 mice. Production of specific antibodies was negligible in the 3 strains. Interleukin-2 treatment elicited significant (p<0.001) decrease in triglycerides (TG) in CD1, and decrease in TG and cholesterol plasma levels and down-regulation of TNF-alpha mRNA expression in C57BL/6 mice. Induction of type 2 cytokines and/or IFN-gamma mRNA expression did not lead to increase in percentage of specific antibody responders in any mouse strain. Exogenous IL-2-related reduction in cholesterol plasma levels and TNF-alpha mRNA expression in C57BL/6 mice was associated with significant (p<0.05) decrease in adult worm recovery and egg count. Treatment with IFN-gamma elicited significant (p<0.05) free FA plasma levels increase in BALB/c and C57BL/6 and decrease in CD1 mice. Expression of type 2 cytokines mRNA was stimulated in BALB/c and CD1 mice, yet was not accompanied with increase in humoral responses. Exogenous IFN-gamma-related reduction in free FA plasma levels and IFN-gamma mRNA response, and up-regulation of TNF-alpha mRNA expression in CD1 mice were associated with significant increase in adult worm burden and egg load. The data were discussed in an attempt to define host factors predictive of resistance to schistosome infection.     

Prevalence of low positive anti-HCV antibodies in blood donors: Schistosoma mansoni co-infection and possible role of autoantibodies

Patients infected with schistosoma frequently show a high seroprevalence of anti-hepatitis C virus (anti-HCV) antibodies. The aim of this study was to find the underlying reason for this phenomenon, and to examine a possible involvement of autoantibodies. Out of 2,400 Egyptian blood donors, 192 (8%) were anti-HCV positive by ELISA. They were 133 males and 59 females with age ranging from 27 to 48 years. According to optical density ratio (ODR) of anti-HCV antibodies, 96 cases were low positive (LP) with ODR (1-2) designated as group I, and 96 were high positive (HP) with ODR (> or =2) (group II). Both groups were examined for quantitative HCV core antigen (HCVcAg), liver function (Albumin, ALT, AST) and anti-Schistosoma mansoni(anti-Sm) IgG. Group I cases were HCVcAg negative with normal liver function tests, and 44 of them were anti-Sm positive. Ninety cases (93.75%) of group II were HCVcAg positive with markedly affected liver function tests and 72 cases were anti-Sm positive. All group I cases were examined for autoimmune markers (ANA, AMA, SMA and LKM). In group I, 33 (75%) of anti-Sm positive cases were positive for one or more of the autoimmune markers examined, while none of anti-Sm negative was positive for any marker with significant difference between the two groups (P < 0.0001). Our results primarily on blood donors indicate that LP anti-HCV frequently represents false-positive reactivity with a possible role of Sm-induced autoantibodies in this phenomenon.