Sound production during agonistic behavior of male Drosophila melanogaster

Male Drosophila fruit flies acquire and defend territories in order to attract females for reproduction. Both, male-directed agonistic behavior and female-directed courtship consist of series of recurrent stereotypical components. Various studies demonstrated the importance of species-specific sound patterns generated by wing vibration as being critical for male courtship success. In this study we analyzed the patterns and importance of sound signals generated during agonistic interactions of male Drosophila melanogaster. In contrast to acoustic courtship signals that consist of sine and pulse patterns and are generated by one extended wing, agonistic signals lack sine-like components and are generally produced by simultaneous movements of both wings. Though intra-pulse oscillation frequencies (carrier frequency) are identical, inter-pulse intervals are twice as long and more variable in aggression signals than in courtship songs, where their precise temporal pattern serves species recognition. Acoustic signals accompany male agonistic interactions over their entire course but occur particularly often after tapping behavior which is a major way to identify the gender of the interaction partner. Since similar wing movements may either be silent or generate sound and wing movements with sound have a greater impact on the subsequent behavior of a receiver, sound producing wing movements seem to be generated intentionally to serve as a specific signal during fruit fly agonistic encounters.     

Comprehensive genetic evaluation of common E-cadherin sequence variants and prostate cancer risk: strong confirmation of functional promoter SNP

The E-cadherin gene (CDH1) has been proposed as a prostate cancer (PC) susceptibility gene in several studies. Aberrant protein expression has been related to prognosis and progression in PC. In addition, a functional promoter SNP (rs16260) has been found to associate with PC risk. We performed a comprehensive genetic analysis of CDH1 by using the method of haplotype tagged SNPs in a large Swedish population-based case-control study consisting of 801 controls and 1,636 cases. In addition, Swedish PC families comprising a total of 157 cases sampled for DNA were analyzed for selected SNPs. Seven SNPs, including the promoter SNP rs16260, that captured over 96% of CDH1 haplotype variation were selected as haplotype tagging SNPs and analyzed for associated PC risk. We observed significant confirmation of rs16260 (P=0.003) for cases with a positive family history of PC (FH+) both in an independent case-control population and in PC families. In addition, a common haplotype (HapB, 25%) including the variant allele of rs16260 was associated (P=0.004) with PC risk among FH+ cases. The promoter SNP rs16260 as well as HapB were significantly transmitted to affected offspring in PC families. We report strong confirmation of the association between PC risk in FH+ cases and a functional CDH1 promoter SNP in an independent population. In conjunction with the biological importance of CDH1 our findings encourage further evaluation of genetic variation in CDH1 in relation to PC etiology. Due to the difficulties in replication of genetic association studies, this finding is unusual and novel.     

Picoeucaryot alga infecting blue mussel Mytilus edulis in southern Norway

During summer 2001, blue mussels Mytilus edulis with abnormal shell growth were collected near Krager?, southern Norway. The mussels had green spots in their mantle tissues, mainly posteriorly and ventrally, and in the adductor muscle. Mussels from 4 sites had a prevalence of green spots varying from 2 to 71% that correlated well with shell deformities. Histological examination revealed the presence of round or ovoid algae, 0.9 to 1.5 x 1.2 to 2.4 microm, free within haemocytes and in the lesions, characterised by an inflammatory response and the presence of cellular debris. The alga contain a relatively large nucleus, 1 chloroplast and 1 mitochondrion. Size and morphology suggest that the alga might be a picoeucaryot green alga. Infection of mussel tissues appears to start in the posterior mantle edge, near the siphons, and spread anterior-ventrally in the mantle connective and storage tissues-occasionally spots were also found in the gonad follicles. Large infected areas were also observed in sinuses within the adductor muscle. Only mussels that were 3 yr old or more were infected. Deformations apparently resulted from years of continuous shell formation by a contracted, partly deformed mantle. Most deformed mussels had eroded shells, allowing some light penetration through the exposed, thin nacre. Young, thin-shelled mussels were not infected. The present work suggests that the alga has, at least partially, a parasitic relationship with the mussels, and is associated with pathological alterations in mussel tissues.     

Intracellular metabolite profiling of Fusarium oxysporum converting glucose to ethanol

The filamentous fungus Fusarium oxysporum is known for its ability to produce ethanol by simultaneous saccharification and fermentation (SSF) of cellulose. However, the conversion rate is low and significant amounts of acetic acid are produced as a by-product. In this study, the growth characteristics of F. oxysporum were evaluated in a minimal medium using glucose as the sole carbon source in aerobic, anaerobic and oxygen-limited batch cultivations. Under aerobic conditions the maximum specific growth rate was found to be 0.043 h(-1), and the highest ethanol yield (1.66 mol/mol) was found under anaerobic conditions. During the different phases of the cultivations, the intracellular profiles were determined under aerobic and anaerobic conditions. The profiles of the phosphorylated intermediates indicated that there was a high glycolytic flux at anaerobic growth conditions, characterized by high efflux of glyceraldehyde-3-phosphate (G3P) and fructose-6-phosphate (F6P) from the pentose phosphate pathway (PPP) to the Embden-Meyerhof-Parnas (EMP) pathway, resulting in the highest ethanol production under these conditions. The amino acid profile clearly suggests that the TCA cycle was primarily active under aerobic cultivation. On the other hand, the presence of high levels of gamma-amino-n-butyric acid (GABA) under anaerobic conditions suggests a functional GABA bypass and a possible block in the TCA cycle at these conditions.     

Essential amino acids of the hantaan virus N protein in its interaction with RNA

The nucleocapsid (N) protein of hantavirus encapsidates viral genomic and antigenomic RNAs. Previously, deletion mapping identified a central, conserved region (amino acids 175 to 217) within the Hantaan virus (HTNV) N protein that interacts with a high affinity with these viral RNAs (vRNAs). To further define the boundaries of the RNA binding domain (RBD), several peptides were synthesized and examined for the ability to bind full-length S-segment vRNA. Peptide 195-217 retained 94% of the vRNA bound by the HTNV N protein, while peptides 175-186 and 205-217 bound only 1% of the vRNA. To further explore which residues were essential for binding vRNA, we performed a comprehensive mutational analysis of the amino acids in the RBD. Single and double Ala substitutions were constructed for 18 amino acids from amino acids 175 to 217 in the full-length N protein. In addition, Ala substitutions were made for the three R residues in peptide 185-217. An analysis of protein-RNA interactions by electrophoretic mobility shift assays implicated E192, Y206, and S217 as important for binding. Chemical modification experiments showed that lysine residues, but not arginine or cysteine residues, contribute to RNA binding, which agreed with bioinformatic predictions. Overall, these data implicate lysine residues dispersed from amino acids 175 to 429 of the protein and three amino acids located in the RBD as essential for RNA binding.     

Impact of dry mouth conditions on oral health-related quality of life in older people

Objective: The aim of the present study was to evaluate the impact of dry mouth conditions on oral health‐related quality of life in frail old people, residents at community care centers. Further, reliability and validity of a visual analogue scale (VAS) for dry mouth symptoms were determined within the study cohort. Background: In old people functional, social and psychological impacts of oral conditions are associated with an overall sense of well being and general health. Subjective dry mouth and reduced saliva flow are common disorders in old people caused by disease and medication. Thus, dry mouth conditions may be determinants for compromised oral health‐related quality of life in old people. Method: In total, 50 old people living at service homes for the old people were asked to answer questionnaires on subjective dry mouth (VAS) and Oral Health Impact Profile (OHIP14) for oral health‐related quality of life. Saliva flow was estimated by absorbing saliva into a pre‐weighed cotton roll. Results: The final study cohort comprised 41 old people (aged 83–91 years). Significant associations were identified between both objective and subjective dry mouth and overall or specific aspects of oral health‐related quality of life. Conclusion: Dry mouth (objective and subjective) is significantly associated with oral health‐related quality of life strengthening the value of monitoring dry mouth conditions in the care of frail old people.