Modeling Drosophila gut microbe interactions reveals metabolic interconnectivity.

We know a lot about varying gut microbiome compositions. Yet, how the bacteria affect each other remains elusive. In mammals, this is largely based on the sheer complexity of the microbiome with at least hundreds of different species. Thus, model organisms such as Drosophila melanogaster are commonly used to investigate mechanistic questions as the microbiome consists of only about 10 leading bacterial species. Here, we isolated gut bacteria from laboratory-reared Drosophila, sequenced their respective genomes, and used this information to reconstruct genome-scale metabolic models. With these, we simulated growth in mono- and co-culture conditions and different media including a synthetic diet designed to grow Drosophila melanogaster. Our simulations reveal a synergistic growth of some but not all gut microbiome members, which stems on the exchange of distinct metabolites including tricarboxylic acid cycle intermediates. Culturing experiments confirmed our predictions. Our study thus demonstrates the possibility to predict microbiome-derived growth-promoting cross-feeding.

Visualization of endogenous gut bacteria in Drosophila melanogaster using fluorescence in situ hybridization.

All metazoans are colonized by a complex and diverse set of microorganisms. The microbes colonize all parts of the body and are especially abundant in the gastrointestinal tract, where they constitute the gut microbiome. The fruit fly Drosophila melanogaster turned out to be an exquisite model organism to functionally test the importance of an intact gut microbiome. Still, however, fundamental questions remain unanswered. For example, it is unknown whether a fine-tuned regionalization of the gut microbiome exists and how such a spatial organization could be established. In order to pave the way for answering this question, we generated an optimized and adapted fluorescence in situ hybridization (FISH) protocol. We focused on the detection of the two major Drosophila gut microbiome constituting bacteria genera: Acetobacter and Lactobacillus. FISH allows to detect the bacteria in situ and thus to investigate their spatial localization in respect to the host as well as to other microbiome members. We demonstrate the applicability of the protocol using a diverse set of sample types.

CG32803 is the fly homolog of LDAF1 and influences lipid storage in vivo.

The Seipin protein is a conserved key component in the biogenesis of lipid droplets (LDs). Recently, a cooperation between human Seipin and the Lipid droplet assembly factor 1 (LDAF1) was described. LDAF1 physically interacts with Seipin and the holocomplex safeguards regular LD biogenesis. The function of LDAF1 proteins outside mammals is less clear. In yeast, the lipid droplet organization (LDO) proteins, which also cooperate with Seipin, are the putative homologs of LDAF1. While certain functional aspects are shared between the LDO and mammalian LDAF1 proteins, the relationship between the proteins is under debate. Here, we identify the Drosophila melanogaster protein CG32803, which we re-named to dmLDAF1, as an insect member of this protein family. dmLDAF1 decorates LDs in cultured cells and in vivo and the protein is linked to the fly and mouse Seipin proteins. Altering the dmLDAF1 abundance affects LD size, number and overall lipid storage amounts. Our results suggest that the LDAF1 proteins thus fulfill an evolutionarily conserved function in the biogenesis and biology of LDs.

Sleeping pattern before thoracic surgery: A comparison of baseline and night before surgery.

BACKGROUND: Sleep deprivation is considered a stress factor in the perioperative period. There are several studies on sleep disturbance after surgery but very limited literature available on preoperative sleep patterns, predictors of sleep disturbance and its effect on surgical outcome. METHODOLOGY: Patients scheduled for thoracic surgery were asked to fill out a written Pittsburgh Sleep Quality Index (PSQI) questionnaire. The primary investigator explained this form to all the patients. This was filled out before premedication for subjective assessment of sleeping pattern at two different time point. Only those patients included who spent the previous night at home. Participants were asked to respond to the questions regarding their baseline sleeping pattern and compare it with last night. RESULTS: Total eighty-three patients with a mean age of 47.83 ± 17.88 were included in the study. Overall mean PSQI scores were significantly higher (p-value < 0.01) during the night before surgery (6.94 ± 2.115) when compared with baseline (3.88 ± 1.877). Sleep latency was also significantly affected when last night-1 (the night before admission) was compared with usual sleep latency. Twenty patients were unable to sleep more than 5 hrs at night before admission which was significant when compared with their last month status (20 vs 3). Logistic regression model demonstrated the age and Timing of surgery as a strong predictors of poor sleep (defined as PSQI ≥ 5). CONCLUSION: Quality of sleep was profoundly affected at night before thoracic surgery, mainly due to a significant change in sleep latency and sleep duration. Although age and Timing of surgery were strong predictors of poor sleep we were unable to find any association between quality of sleep and type of surgery.

Control of Drosophila Growth and Survival by the Lipid Droplet-Associated Protein CG9186/Sturkopf.

Lipid droplets (LDs) are the universal cellular storage organelles for esterified neutral lipids. The increasing number of characterized LD-associated proteins attained LDs with hitherto unexpected functions on top of their classical role as energy depot. Here, we characterize the LD-associated protein CG9186 of Drosophila by a CRISPR/Cas9-derived mutant fly line. While the mutant flies only showed a mild triacylglycerol storage phenotype, they were highly protected from desiccation stress, likely linked to a reduced locomotor activity and altered cuticular hydrocarbons. Both parameters depend on juvenile hormone (JH) signaling. Together with an observed interaction between CG9186 and JH-degrading enzymes, our results suggest that CG9186 participates in endocrine physiology regulation. In support of this hypothesis, CG9186 mutant flies show an altered expression of JH target genes and fail to adjust their developmental rate to dietary yeast-to-sugar ratio changes. Our results thus link LDs to organismic physiology regulation.

ASSESSING THE KNOWLEDGE, ATTITUDES AND PRACTICES OF SCHOOL TEACHERS REGARDING DYSLEXIA, ATTENTION-DEFICIT/ HYPERACTIVITY AND AUTISTIC SPECTRUM DISORDERS IN KARACHI, PAKISTAN.

BACKGROUND: Learning impairments in children consist of a spectrum of disorders that are under diagnosed in Pakistan. Most learning disorders have long term consequences for a child and early detection is thus imperative. Teachers may be able to play a key role in such identification. The objective of our study was to survey knowledge, attitudes and practices of school teachers regarding dyslexia, Attention-deficit/hyperactivity disorder (ADHD) and autistic spectrum disorder, and assess their ability to identify learning disabilities. METHODS: A cross-sectional study was conducted with 233 primary school teachers from Karachi using a self-administered questionnaire. RESULTS: Mean scores for the knowledge test and the ability to identify learning- impaired children were 58.8% and 53.3%, respectively. Better qualified teachers scored significantly more on the knowledge and ability to identify learning impairments sections. Most teachers believed that these students should study in mainstream schools with special educators. Majority of the teachers belonged to schools where children with learning disabilities were detected using teachers' judgment. Most teachers manage these children by involving them in discussions, seating them at the front of the class, and giving them extra time. CONCLUSION: Knowledge about learning disabilities is very low amongst school teachers, which may limit their ability to identify learning impairments.

Effectiveness of premedication at the time of separation from parent and mask induction in paediatric patients coming for congenital heart disease surgery.

OBJECTIVE: To compare the effectiveness of oral midazolam and chloral hydrate on anxiety and sedation at various stages of pre-operative period in congenital heart surgery patients. STUDY DESIGN: Cross-sectional comparative study. PLACE AND DURATION OF STUDY: Operating rooms of The Aga Khan University Hospital, Karachi, from October 2009 to December 2010. METHODOLOGY: Sixty-six patients between the ages of 6 months and 6 years received either chloral hydrate (Group C) or midazolam (Group M) pre-operatively. All congenital heart disease patients coming for cardiac surgeries were included while cases of emergency surgery and those patients in whom premedication was not given were excluded. Effect of premedication observed and documented by Anaesthesia Consultant. Documentation included demographics, level of anxiety and sedation at the time of separation from parent and at the time of mask application. RESULTS: Forty study subjects were male (61%) and 26 were females (39%). Eleven patients received oral midazolam while 55 received oral chloral hydrate. Sixteen patients were tearful and anxious (24%) while rests were calm and asleep. Thirty patients in group C (60%) were well sedated at the time of separation. Mask induction was satisfactory in 76% of chloral hydrate patients. Increase dose was suggested in 23 patients by anaesthetizing physician. Out of these 6 belonged to group M (54.5%) while 17 to low dose chloral hydrate group (30.9%) [< 40 mg/kg]. CONCLUSION: Chloral hydrate provides comparable anxiolysis but superior sedation and mask acceptance scores when compared with midazolam. Higher doses of chloral hydrate (50 mg/kg) were required to keep these patients calm and peaceful at the time of mask application for inhalation induction.

Continued lumbar spinal erosion after repair of chronic contained rupture of a mycotic abdominal aortic aneurysm.

INTRODUCTION: Mycotic aneurysm of the aorta is a rare, dangerous condition. We report a case of an abdominal aortic aneurysm (AAA) caused by Candida albicans. METHODS: Case report and review of pertinent English-language literature. CASE REPORT: A 48 year-old man presented with an acute exacerbation of long-standing back pain. Examination revealed a pulsatile epigastric mass, and radiologic examinations confirmed a 9 cm chronic contained rupture of an inflammatory infrarenal AAA. At operation, no posterior aneurysm sac was found, and lumbar vertebral erosion was noted. Lower limb vascularity was secured with left axillo-bifemoral bypass. The patient presented 12 months later with severe non-mechanical back pain. Imaging confirmed continuing vertebral erosion. At laparotomy, an autologous fibula strut was used for spinal stabilization. CONCLUSION: Aggressive multimodality therapy of infected AAA and associated vertebral osteomyelitis is necessary for a successful outcome.