Genome-wide association study of anthropometric traits and evidence of interactions with age and study year in Filipino women

Increased values of multiple adiposity-related anthropometric traits are important risk factors for many common complex diseases. We performed a genome-wide association (GWA) study for four quantitative traits related to body size and adiposity (BMI, weight, waist circumference, and height) in a cohort of 1,792 adult Filipino women from the Cebu Longitudinal Health and Nutrition Survey (CLHNS). This is the first GWA study of anthropometric traits in Filipinos, a population experiencing a rapid transition into a more obesogenic environment. In addition to identifying suggestive evidence of additional single-nucleotide polymorphism (SNP) association signals (P < 10(-5)), we replicated (P < 0.05, same direction of additive effect) associations previously reported in European populations of both BMI and weight with MC4R and FTO, of BMI with BDNF, and of height with EFEMP1, ZBTB38, and NPPC, but none with waist circumference. We also replicated loci reported in Japanese or Korean populations as associated with BMI (OTOL1) and height (HIST1H1PS2, C14orf145, GPC5). A difference in local linkage disequilibrium (LD) between European and Asian populations suggests a narrowed association region for BDNF, while still including a proposed functional nonsynonymous amino acid substitution variant (rs6265, Val66Met). Finally, we observed significant evidence (P < 0.0042) for age-by-genotype interactions influencing BMI for rs17782313 (MC4R) and rs9939609 (FTO), and for a study year-by-genotype interaction for rs4923461 (BDNF). Our results show that several genetic risk factors are associated with anthropometric traits in Filipinos and provide further insight into the effects of BDNF, FTO, and MC4R on BMI.     

Ammonia flux,physiological parameters,and <Emphasis Type="Italic">Symbiodinium</Emphasis> diversity in the anemonefish symbiosis on Red Sea coral reefs

Despite the ecological importance of anemonefish symbioses, little is known about how nutritional contributions from anemonefish interact with sea anemone physiology and Symbiodinium (endosymbiotic dinoflagellate) genetic identity under field conditions. On Red Sea coral reefs, we measured variation in ammonia concentrations near anemones, excretion rates of anemonefish, physiological parameters of anemones and Symbiodinium, and genetic identity of Symbiodinium within anemones. Ammonia concentrations among anemone tentacles were up to 49% above background levels, and anemonefish excreted ammonia significantly more rapidly after diurnal feeding than they did after nocturnal rest, similar to their excretion patterns under laboratory conditions. Levels of 4 physiological parameters (anemone protein content, and Symbiodinium abundance, chlorophyll a concentration, and division rate) were similar to those known for laboratory-cultured anemones, and in the field did not depend on the number of anemonefish per anemone or depth below sea surface. Symbiodinium abundance varied significantly with irradiance in the shaded reef microhabitats occupied by anemones. Most anemones at all depths harbored a novel Symbiodinium 18S rDNA variant within internal transcribed spacer region 2 (ITS2) type C1, while the rest hosted known ITS2 type C1. Association with Symbiodinium Clade C is consistent with the symbiotic pattern of these anemones on other Indo-Pacific reefs, but the C1 variant of Symbiodinium identified here has not been described previously. We conclude that in the field, anemonefish excrete ammonia at rapid rates that correlate with elevated concentrations among host anemone tentacles. Limited natural variation in anemonefish abundance may contribute to consistently high levels of physiological parameters in both anemones and Symbiodinium, in contrast to laboratory manipulations where removal of fish causes anemones to shrink and Symbiodinium to become less abundant.     

A Theoretical Approach to Study the Evolution of Aggregation Behavior by Larval Codling Moth, <Emphasis Type="BoldItalic">Cydia pomonella</Emphasis> (Lepidoptera: Tortricidae)

Pupation site-seeking larvae of the codling moth, Cydia pomonella, aggregate in response to aggregation pheromone produced by cocoon-spinning conspecific larvae. Larvae that pupate in an aggregation rather than in solitude may experience a lower rate of parasitism by the parasitoid Mastrus ridibundus. Additionally, adults eclosing from a larval aggregation may encounter mates more rapidly at the site of eclosion (on-site) than away from that site (off-site). We employed an evolutionary simulation to determine the effect of several ecological parameters on the evolution of larval aggregation behavior. These parameters included (i) the probability of mate encounter off-site; (ii) the time available for finding a mate; and (iii) the population density of parasitoids and their rate of larval parasitism. The model predicts that larval aggregation behavior is selected for when the probability of off-site mate encounter is low, the time to locate mates is short, and egg-limited parasitoids are at high population levels. We also show that aggregations reduce the risk of parasitism through dilution effects. The parameters found to favour the evolution of larval aggregation behavior are consistent with life history traits exhibited by C. pomonella.     

A methylated phosphate group and four amide-linked acyl chains in leptospira interrogans lipid A. The membrane anchor of an unusual lipopolysaccharide that activates TLR2

Leptospira interrogans differs from other spirochetes in that it contains homologs of all the Escherichia coli lpx genes required for the biosynthesis of the lipid A anchor of lipopolysaccharide (LPS). LPS from L. interrogans cells is unusual in that it activates TLR2 rather than TLR4. The structure of L. interrogans lipid A has now been determined by a combination of matrix-assisted laser desorption ionization time-of-flight mass spectrometry, NMR spectroscopy, and biochemical studies. Lipid A was released from LPS of L. interrogans serovar Pomona by 100 degrees C hydrolysis at pH 4.5 in the presence of SDS. Following purification by anion exchange and thin layer chromatography, the major component was shown to have a molecular weight of 1727. Mild hydrolysis with dilute NaOH reduced this to 1338, consistent with the presence of four N-linked and two O-linked acyl chains. The lipid A molecules of both the virulent and nonvirulent forms of L. interrogans serovar Icterohaemorrhagiae (strain Verdun) were identical to those of L. interrogans Pomona by the above criteria. Given the selectivity of L. interrogans LpxA for 3-hydroxylaurate, we propose that L. interrogans lipid A is acylated with R-3-hydroxylaurate at positions 3 and 3' and with R-3-hydroxypalmitate at positions 2 and 2'. The hydroxyacyl chain composition was validated by gas chromatography and mass spectrometry of fatty acid methyl esters. Intact hexa-acylated lipid A of L. interrogans Pomona was also analyzed by NMR, confirming the presence a beta-1',6-linked disaccharide of 2,3-diamino-2,3-dideoxy-d-glucopyranose units. Two secondary unsaturated acyl chains are attached to the distal residue. The 1-position of the disaccharide is derivatized with an axial phosphate moiety, but the 4'-OH is unsubstituted. (1)H and (31)P NMR analyses revealed that the 1-phosphate group is methylated. Purified L. interrogans lipid A is inactive against human THP-1 cells but does stimulate tumor necrosis factor production by mouse RAW264.7 cells.     

Leucine-specific, functional interactions between human immunodeficiency virus type 1 Nef and adaptor protein complexes

The human immunodeficiency virus type 1 virulence protein Nef interacts with the endosomal sorting machinery via a leucine-based motif. Similar sequences within the cytoplasmic domains of cellular transmembrane proteins bind to the adaptor protein (AP) complexes of coated vesicles to modulate protein traffic, but the molecular basis of the interactions between these motifs and the heterotetrameric complexes is controversial. To identify the target of the Nef leucine motif, the native sequence was replaced with either leucine- or tyrosine-based AP-binding sequences from cellular proteins, and the interactions with AP subunits were correlated with function. Tyrosine motifs predictably modulated the interactions between Nef and the mu subunits of AP-1, AP-2, and AP-3; heterologous leucine motifs caused little change in these interactions. Conversely, leucine motifs mediated a ternary interaction between Nef and hemicomplexes containing the sigma1 plus gamma subunits of AP-1 or the sigma3 plus delta subunits of AP-3, whereas tyrosine motifs did not. Similarly, only leucine motifs supported the Nef-mediated association of AP-1 and AP-3 with endosomal membranes in cells treated with brefeldin A. Functionally, Nef proteins containing leucine motifs down-regulated CD4 from the cell surface and enhanced viral replication, whereas those containing tyrosine motifs were inactive. Apparently, the interaction of Nef with the mu subunits of AP complexes is insufficient for function. A leucine-specific mode of interaction that likely involves AP hemicomplexes is further required for Nef activity. The mu and hemicomplex interactions may cooperate to yield high avidity binding of AP complexes to Nef. This binding likely underlies the unusual ability of Nef to induce the stabilization of these complexes on endosomal membranes, an activity that correlates with enhancement of viral replication.     

Transport of (Glyco)Sphingolipids in and Between Cellular Membranes; Multidrug Transporters and Lateral Domains

Sphingolipids are highly enriched in the outer leaflet of the plasma membrane lipid bilayer. However, the first glycolipid, glucosylceramide, is synthesized in the opposite, cytosolic leaflet of the Golgi membrane. This has led us to experiments which suggest that the level of glucosylceramide in the cytosolic surface is carefully regulated both by the balance between synthesis and hydrolysis and by transport away from this surface through translocators, multidrug transporters, the same molecules that make cancer cells resistant to chemotherapy. Our data suggest a role for newly synthesized glucosylceramide not only in the formation of domains in the luminal leaflet of the Golgi but also on the cytosolic surface of this organelle.     

The role of silk in courtship and chemical communication of the false widow spider, <Emphasis Type="Italic">Steatoda grossa</Emphasis> (Araneae: Theridiidae)

In spiders, sex pheromones are often associated with silk produced by females, and function in mate attraction, recognition, and evaluation. Silk-bound pheromones typically elicit courtship behaviour in web-building spiders. Here we (1) describe courtship interactions of Steatoda grossa males with virgin or mated females, and (2) show that silk and methanol extracts of silk produced by virgin females trigger courtship behaviour (silk production) by males, whereas silk of mated females does not. Our results indicate that (1) virgin females produce a silk-bound sex pheromone, (2) males discriminate between virgin and mated females based on silk cues, and (3) male silk likely functions in sexual communication.     

The extracellular calcium-sensing receptor (CaSR) on human esophagus and evidence of expression of the CaSR on the esophageal epithelial cell line (HET-1A)

Gastrointestinal reflux disease and eosinophilic esophagitis are characterized by basal cell hyperplasia. The extracellular calcium-sensing receptor (CaSR), a G protein-coupled receptor, which may be activated by divalent agonists, is expressed throughout the gastrointestinal system. The CaSR may regulate proliferation or differentiation, depending on cell type and tissue. The current experiments demonstrate the expression of the CaSR on a human esophageal epithelial cell line (HET-1A) and the location and expression of the CaSR in the human esophagus. CaSR immunoreactivity was seen in the basal layer of normal human esophagus. CaSR expression was confirmed in HET-1A cells by RT-PCR, immunocytochemistry, and Western blot analysis. CaSR stimulation by extracellular calcium or agonists, such as spermine or Mg(2+), caused ERK1 and 2 activation, intracellular calcium concentration ([Ca(2+)](i)) mobilization (as assessed by microspecfluorometry using Fluo-4), and secretion of the multifunctional cytokine IL-8 (CX-CL8). HET-1A cells transiently transfected with small interfering (si)RNA duplex against the CaSR manifested attenuated responses to Ca(2+) stimulation of phospho- (p)ERK1 and 2, [Ca(2+)](i) mobilization, and IL-8 secretion, whereas responses to acetylcholine (ACh) remained sustained. An inhibitor of phosphatidylinositol-specific phospholipase C (PI-PLC) (U73122) blocked CaSR-stimulated [Ca(2+)](i) release. We conclude that the CaSR is present on basal cells of the human esophagus and is present in a functional manner on the esophageal epithelial cell line, HET-1A.     

Bimodal cue complex signifies suitable oviposition sites to gravid females of the common green bottle fly

Gravid females of the common green bottle fly, Lucilia sericata Meigen (Diptera: Calliphoridae), readily locate recently deceased vertebrates as oviposition sites, particularly when these animals have been injured. We investigated semiochemical and visual cues that mediate attraction of gravid females to fresh rat carrion. Female flies were more strongly attracted to incised rat carrion than to intact carrion. They were also attracted to Porapak Q headspace volatile (HSV) extract of incised rat carrion. Analyzing aliquots of Porapak Q HSV extract by gas chromatographic‐electroantennographic detection revealed nine components [phenol, para‐ and/or meta‐cresol (could not be separated), guaiacol, dimethyl trisulfide (DMTS), phenylacetaldehyde, (E)‐2‐octenal, nonanal, and tetramethyl pyrazine] that consistently elicited responses from blow fly antennae. In laboratory experiments, a synthetic blend of these nine components was as attractive to gravid females as Porapak Q HSV extract, but blend attractiveness was due entirely to DMTS. In both laboratory and field experiments, increasing doses of DMTS attracted increasingly more flies. Coupled with DMTS, carrion‐type color cues (dark red, black) were more effective than bright color cues (white, yellow) in attracting flies. In field experiments, dark traps baited with DMTS captured a total of 214 calliphorid flies (200 L. sericata, 10 Lucilia illustris Meigen, three Calliphora vicina Robineau‐Desvoidy, one Calliphora vomitoria L.), all of which were gravid females. These results support the conclusion that DMTS and dark color represent a bimodal cue complex that signifies suitable oviposition sites to gravid calliphorid females, particularly L. sericata.