No abstract

Caenorhabditis elegans uses ascaroside pheromones to induce development of the stress-resistant dauer larval stage and to coordinate various behaviors. Peroxisomal β-oxidation cycles are required for the biosynthesis of the fatty acid-derived side chains of the ascarosides. Here we show that three acyl-CoA oxidases, which catalyze the first step in these β-oxidation cycles, form different protein homo-and heterodimers with distinct substrate preferences. Mutations in the acyl-CoA oxidase genes acox-1, -2, and -3 led to specific defects in ascaroside production. When the acyl-CoA oxidases were expressed alone or in pairs and purified, the resulting acyl-CoA oxidase homo-and heterodimers displayed different sidechain length preferences in an in vitro activity assay. Specifically, an ACOX-1 homodimer controls the production of ascarosides with side chains with nine or fewer carbons, an ACOX-1/ACOX-3 heterodimer controls the production of those with side chains with seven or fewer carbons, and an ACOX-2 homodimer controls the production of those with ω-side chains with less than five carbons. Our results support a biosynthetic model in which β-oxidation enzymes act directly on the CoA-thioesters of ascaroside biosynthetic precursors. Furthermore, we identify environmental conditions, including high temperature and low food availability, that induce the expression of acox-2 and/or acox-3 and lead to corresponding changes in ascaroside production. Thus, our work uncovers an important mechanism by which C. elegans increases the production of the most potent dauer pheromones, those with the shortest side chains, under specific environmental conditions. dauer | pheromone | ascaroside | beta-oxidation | acyl-CoA oxidase

Pooled prevalence of CD among FDRs is 7.5% and varies considerably with their relationship with the index patient. The risk of CD in FDRs also varies according to gender and geographical location.

Background/AimsThe prevalence of irritable bowel syndrome (IBS) varies from 4% to 20% in different Asian nations. Prevalence of IBS in native North Indian community is not known.MethodsBetween November 2008 to December 2009, we estimated the prevalence of IBS in a rural community of Ballabgarh block, located in Haryana state. A structured questionnaire based on Rome III module was used to collect symptoms related to IBS from all the participants in a door to door survey. A Rome III criterion was used for diagnosis of IBS. IBS was further classified based on predominance of symptoms as constipation predominant, diarrhea predominant, mixed and unspecified based on Rome III module.ResultsThere were 4,767 participants (mean age 34.6 ± 10.8, males 50%). Overall, 555 (11.6%; 95% CI, 10.7-12.5) had constipation, 542 (11.4%; 95% CI, 10.5-12.3) diarrhea and 823 (17.3%; 95% CI, 16.2-18.4) abdominal pain. The overall prevalence of IBS was 4% (95% CI, 3.5-4.6). The prevalence of constipation predominant IBS was 0.3% (95% CI, 0.16-0.49), diarrhea predominant IBS 1.5% (95% CI, 1.18-1.90), mixed IBS 1.7% (95% CI, 1.35-2.11) and unsubtyped IBS 0.5% (95% CI, 0.32-0.75). The prevalence of IBS was significantly higher in females compared with males (4.8% vs 3.2%, P = 0.008). However, there was no significant difference between males and females in the prevalence of different subtypes of IBS. The prevalence increased with age.ConclusionsThe prevalence of IBS in a North Indian community is 4%. IBS poses a significant burden on the rural adults.

IBS-D and IBS-M patients have lower IBS-QOL than IBS-C patients. Clinicians should recognize food avoidance, effects on daily activities and relationship problems in these patients.

The sensation of nausea is a common occurrence with diverse causes and a significant disease burden. Nausea is considered to function as a protective mechanism, warning the organism to avoid potential toxic ingestion. Less adaptive circumstances are also associated with nausea, including post-operative nausea, chemotherapy-induced nausea, and motion sickness. A common definition of nausea identifies the symptom as a precursor to the act of vomiting. The interaction, though present, does not appear to be a simple relationship. Nausea is unfortunately the 'neglected symptom', with current accepted therapy generally directed at improving gastrointestinal motility or acting to relieve emesis. Improved understanding of the pathophysiological basis of nausea has important implications for exploiting novel mechanisms or developing novel therapies for nausea relief.

Celiac disease is not uncommon in Asia, and the sero-prevalence and prevalence of CD in Asia are 1.6% and 0.5%, respectively. The prevalence of CD varies with gender and geographic location. There is a need for population-based prevalence studies in many Asian countries to properly estimate the burden of CD in Asia.

Background/AimsTo study the prevalence of somatic and psychiatric co-morbidities in the patients of irritable bowel syndrome (IBS) and to assess the quality of life (QOL) of these patients.MethodsOne hundred and eighty-four IBS patients and 198 controls were included. Diagnosis of IBS, its sub-classification and assessment of other functional gastrointestinal disorders (FGIDs) was made on basis of Rome III criteria. Severity of IBS was assessed using IBS severity scoring system. Psychiatric evaluation was done using Patient Heath Questionnaire. QOL was evaluated using WHO QOL-BREF.ResultsOne hundred and forty-seven (79.9%) and 158 (85.9%) patients with IBS had at least one other FGID or at least one somatic co-morbidity, respectively. Higher number of patients had at least one psychiatric co-morbidity compared to controls (79.9% vs 34.3%; P < 0.001). Major depressive syndrome (47.3% vs 5.1%; P < 0.001), somatoform disorder (50% vs 14.6%; P < 0.001) and panic syndrome (44% vs 11.6%; P < 0.001) were more common in IBS than controls. Only 14 (7.6%) patients were receiving drug treatment for their psychiatric illness. Severe IBS symptoms were present in significantly higher number of patients with constipation predominant IBS than diarrhea predominant IBS. Those with severe disease had higher prevalence of psychiatric (95.1%) and somatic (96.7%) co-morbidities compared with mild disease. QOL of IBS patients was significantly lower in all four domains compared to controls. Presence of at least one other FGID was significantly associated with presence of one or more psychiatric co-morbidity (P < 0.001).ConclusionsMajority of IBS patients presenting to a tertiary care center had associated psychiatric, somatic co-morbidities and reduced QOL. Very few of them received specific psychiatric treatment.