A study of genetic association with electrophysiological measures related to alcoholism: GAW14 data

Recently, alcohol-related traits have been shown to have a genetic component. Here, we study the association of specific genetic measures in one of the three sets of electrophysiological measures in families with alcoholism distributed as part of the Genetic Analysis Workshop 14 data, the NTTH (non-target case of Visual Oddball experiment for 4 electrode placements) phenotypes: ntth1, ntth2, ntth3, and ntth4. We focused on the analysis of the 786 Affymetrix markers on chromosome 4. Our desire was to find at least a partial answer to the question of whether ntth1, ntth2, ntth3, and ntth4 are separately or jointly genetically controlled, so we studied the principal components that explain most of the covariation of the four quantitative traits. The first principal component, which explains 70% of the covariation, showed association but not genetic linkage to two markers: tsc0272102 and tsc0560854. On the other hand, ntth1 appeared to be the trait driving the variation in the second principal component, which showed association and genetic linkage at markers in four regions: tsc0045058, tsc1213381, tsc0055068, and tsc0051777 at map distances 53.26, 85.42, 89.31, and 172.86, respectively. These results show that the partial answer to our starting question for this brief analysis is that the NTTH phenotypes are not jointly genetically controlled. The component ntth1 displays marked genetic linkage.     

Metabolic enzyme activities in black bream (Acanthopagrus butcheri) from the Swan-Canning Estuary, Western Australia

The Swan-Canning estuary, in southwestern Australia, is subject to frequent algal blooms and associated periods of hypoxia due to high levels of nutrients in stormwater runoff and sewage spills. Fish in which cellular respiration is impaired due to chronic exposure to non-nutrient pollutants in the water will have a reduced ability to survive these periods of high stress. In order to investigate if metabolic respiration in black bream (Acanthopagrus butcheri) was altered, fish were collected from five sites in the Swan-Canning estuary in summer 2001, summer 2002 and winter 2002. Aerobic and anaerobic capacities were estimated by measuring the enzymes cytochrome C oxidase (CCO) and lactate dehydrogenase (LDH). Neither seasonal or annual trends, nor upstream or downstream gradients were observed in either biomarker. The fish collected from the Barrack Street site, which is close to the Perth Central Business District, were heavily challenged in their aerobic capacity in the summer months compared to the other sites. In addition, the fish at Barrack Street displayed an altered anaerobic capacity. It is likely that the impaired metabolic capacity of the fish at Barrack Street reduces the fishes' ability to survive the frequent algal blooms within the estuary.     

Azo dye reduction by mesophilic and thermophilic anaerobic consortia

The reduction of the azo dye model compounds Reactive Red 2 (RR2) and Reactive Orange 14 (RO14) by mesophilic (30 degrees C) and thermophilic (55 degrees C) anaerobic consortia was studied in batch assays. The contribution of fermentative and methanogenic microorganisms in both temperatures was evaluated in the presence of the fermentative substrate glucose and the methanogenic substrates acetate, H2/CO2, methanol, and formate. Additionally, the effect of the redox mediator riboflavin on electron shuttling was assessed. We concluded that the application of thermophilic anaerobic treatment is an interesting option for the reductive decolorization of azo dyes compared to mesophilic conditions. The use of high temperature may decrease or even take the place of the need for continuous redox mediator dosage in bioreactors, contrarily to the evident effect of those compounds on dye reduction under mesophilic conditions. Both fermenters and methanogens may play an important role during reductive decolorization of dyes, in which mediators are important not only for allowing the different microbes to participate more effectively in this complex reductive biochemistry but also for assisting in the competition for electrons between dyes and other organic and inorganic electron acceptors.     

Membrane topology of loop 13-14 of the Na+/glucose cotransporter (SGLT1): a SCAM and fluorescent labelling study

The accessibility of the hydrophilic loop between putative transmembrane segments XIII and XIV of the Na+/glucose cotransporter (SGLT1) was studied in Xenopus oocytes, using the substituted cysteine accessibility method (SCAM) and fluorescent labelling. Fifteen cysteine mutants between positions 565 and 664 yielded cotransport currents of similar amplitude than the wild-type SGLT1 (wtSGLT1). Extracellular, membrane-impermeant MTSES(-) and MTSET(+) had no effect on either cotransport or Na+ leak currents of wtSGLT1 but 9 mutants were affected by MTSES and/or MTSET. We also performed fluorescent labelling on SGLT1 mutants, using tetramethylrhodamine-5-maleimide and showed that positions 586, 588 and 624 were accessible. As amino acids 604 to 610 in SGLT1 have been proposed to form part of a phlorizin (Pz) binding site, we measured the K(i)(Pz) and K(m)(alphaMG) for wtSGLT1 and for cysteine mutants at positions 588, 605-608 and 625. Although mutants A605C, Y606C and D607C had slightly higher K(i)(Pz) values than wtSGLT1 with minimal changes in K(m)((alpha)MG), the effects were modest and do not support the original hypothesis. We conclude that the large, hydrophilic loop near the carboxyl terminus of SGLT1 is thus accessible to the external solution but does not appear to play a major part in the binding of phlorizin.     

Loss of pro-apoptotic Bim promotes accumulation of pulmonary T lymphocytes and enhances allergen-induced goblet cell metaplasia

Immunological tolerance during prolonged exposure to allergen is accompanied by a shift in the lymphocyte content and a reduction of goblet cell metaplasia (GCM). Bim initiates negative selection of autoreactive T and B cells and shut down of T cell immune responses in vivo. The present study investigated whether Bim plays a role in the resolution of GCM during prolonged exposure to allergen. Loss of Bim increased T lymphocyte numbers in the bronchoalveolar lavage at 4 and 15 days of allergen exposure. The numbers of pulmonary CD4(+)8(-), CD4(-)8(+), and gammadelta T cells were significantly higher in naive and allergen-challenged bim(-/-) mice compared with wild-type (WT) littermates. When activated, pulmonary bim(-/-) T cells produced increased levels of IFNgamma compared with bim(+/+) T cells. No differences were noted in the total numbers of epithelial cells per millimeter of basal lamina between bim(+/+) and bim(-/-) mice, and the rate of resolution over 15 days of exposure was similar in both groups of mice. However, GCM was significantly enhanced and expression of IL-13Ralpha2 was reduced in bim(-/-) mice compared with WT mice at 4 days. Furthermore, treatment of bronchiolar explant cultures with increasing IFNgamma levels reduced immunostaining for IL-13Ralpha2. Collectively, these studies suggest that, during prolonged exposure to allergen, Bim plays no role in the resolution of GCM, but increased IFNgamma levels in bim(-/-) mice may be responsible for reduced expression of IL-13Ralpha2 and enhanced GCM despite similar levels of IL-13 in bim(+/+) and bim(-/-) mice.     

Solid-phase synthesis of 2-[18F]fluoropropionyl peptides

The 2-[(18)F]fluoropropionic (2-[(18)F]FPA) acid is used as a prosthetic group for radiolabeling proteins and peptides for targeted imaging using positron emission tomography (PET). Radiolabeling of compounds with more than one acylable functional group can lead to complex mixtures of products; however, peptides can be labeled regioselectively on the solid phase. We investigated the use of a solid-phase approach for the preparation of 2-[(18)F]fluoropropionyl peptides. [(18)F]FPA was prepared and conjugated to the peptides attached to the solid phase support. The (18)F-labeled peptides were obtained in 175 min with decay corrected yields of 10% (related to [(18)F]fluoride) and with a purity of 76-99% prior HPLC purification. The suitability of various coupling reagents and solid supports were tested for radiolabeling of several peptides of various lengths.     

Resibufogenin corrects hypertension in a rat model of human preeclampsia

The study of the pathogenesis of preeclampsia has been hampered by a relative dearth of animal models. We developed a rat model of preeclampsia in which the excretion of a circulating inhibitor of Na/K ATPase, marinobufagenin (MBG), is elevated. These animals develop hypertension, proteinuria, and intrauterine growth restriction. The administration of a congener of MBG, resibufogenin (RBG), reduces blood pressure to normal in these animals, as is the case when given to pregnant animals rendered hypertensive by the administration of MBG. Studies of Na/K ATPase inhibition by MBG and RBG reveal that these agents are equally effective as inhibitors of the enzyme.     

A strong quantitative trait locus for wing length on chromosome 2 in a wild population of great reed warblers

Wing length is a key character for essential behaviours related to bird flight such as migration and foraging. In the present study, we initiate the search for the genes underlying wing length in birds by studying a long-distance migrant, the great reed warbler (Acrocephalus arundinaceus). In this species wing length is an evolutionary interesting trait with pronounced latitudinal gradient and sex-specific selection regimes in local populations. We performed a quantitative trait locus (QTL) scan for wing length in great reed warblers using phenotypic, genotypic, pedigree and linkage map data from our long-term study population in Sweden. We applied the linkage analysis mapping method implemented in GridQTL (a new web-based software) and detected a genome-wide significant QTL for wing length on chromosome 2, to our knowledge, the first detected QTL in wild birds. The QTL extended over 25 cM and accounted for a substantial part (37%) of the phenotypic variance of the trait. A genome scan for tarsus length (a body-size-related trait) did not show any signal, implying that the wing-length QTL on chromosome 2 was not associated with body size. Our results provide a first important step into understanding the genetic architecture of avian wing length, and give opportunities to study the evolutionary dynamics of wing length at the locus level.