Effect of Sodium on the Transport and Utilization of Citric Acid by Aerobacter (Enterobacter) aerogenes

Sodium inhibited citrate uptake by two of the four strains of Aerobacter (Enterobacter) aerogenes used in these studies, had no effect on one strain, and stimulated citrate uptake by one strain. Two of the four strains grew well anaerobically on citrate in the presence of Na(+), one grew poorly, and one grew not at all either in the presence or absence of Na(+). Na(+) stimulated the aerobic growth of one strain on citrate, increased the total growth but not the rate of growth of one strain, and prolonged the lag phase but not the rate of growth or total growth of two strains. The experimental data reported herein, therefore, indicate that there are appreciable physiological differences among strains of A. aerogenes.     

Expression of an unusual acidic glycoconjugate in Leishmania donovani

An acidic glycoconjugate containing mannose, galactose and phosphate in approximately equimolar amounts was extracted from Leishmania donovani promastigotes and partially characterized. The glycoconjugate could be metabolically labeled with either [3H]mannose or [3H]galactose and was extractable from a delipidated residue fraction with water/ethanol/diethyl ether/pyridine/concentrated NH4OH (15:15:5:1:0.017) at 25 degrees C. The radioactively labeled glycoconjugate was found to possess the following characteristics: 1) comprised 45-60% of the total [3H]mannose label incorporated into macromolecules; 2) was soluble in alkaline solvents and 0.5% Triton X-100; 3) migrated as a broad band upon electrophoresis on sodium dodecyl sulfate-polyacrylamide gels with an approximate molecular weight of 15,000-30,000; 4) bound to DE52 cellulose and was eluted with a salt gradient of 0-0.1 M NaCl; 5) was insensitive to Pronase, hyaluronidase, chondroitinase, endo-beta-N-acetylglucosaminidase H, and endo-beta-galactosidase; and 6) possessed hydrophobic properties. An unusual feature of the glycoconjugate was its lability to mild acid hydrolysis (0.02 N HCl, 15 min, 60 degrees C). As determined by alkaline phosphatase and glycosidase digestion and paper chromatographic analysis, the major fragment generated by mild acid hydrolysis was found to be a phosphorylated galactosyl-beta-mannose disaccharide. All of these characteristics suggest that the glycoconjugate may be a polysaccharide and, possibly, may be important in parasite-host cell interactions.     

Seahawk: moving beyond HTML in Web-based bioinformatics analysis

Background  

Traditional HTML interfaces for input to and output from Bioinformatics analysis on the Web are highly variable in style, content and data formats. Combining multiple analyses can therfore be an onerous task for biologists. Semantic Web Services allow automated discovery of conceptual links between remote data analysis servers. A shared data ontology and service discovery/execution framework is particularly attractive in Bioinformatics, where data and services are often both disparate and distributed. Instead of biologists copying, pasting and reformatting data between various Web sites, Semantic Web Service protocols such as MOBY-S hold out the promise of seamlessly integrating multi-step analysis.     

Seasonal dynamics of Anopheles species at three locations in the Republic of Korea

Weekly changes in adult Anopheles species were monitored at Camp Humphreys (CH), Ganghwa Island (GH), and Warrior Base (WB), from May‐October, 2009–2010 to explore the relationship between Plasmodium vivax development and vector dynamics in the Republic of Korea (ROK). Adult females were trapped and dissected to determine parity for estimating longevity, mortality, and birthrate. A degree‐day (DD) method was used to estimate the extrinsic incubation period (EIP) of P. vivax and duration of the gonotrophic cycle and other life stages. Anopheles sinensis was the predominant species, with satellite data showing peak abundance occurring after the period of maximum greenness. Abundance peaks were location dependent, comprised nulliparous and parous females, and timing could not be fully explained by DD estimation. Parity showed synchronicity between locations and years and was highest for September and lowest during maximum greenness. Mosquito longevity was predicted to exceed the EIP (when malaria transmission is possible) during weeks 29, 31, 34, and near the end of the season. Area‐wide changes in parity suggest a common cause; information on local larval habitat and agricultural practices may explain location‐specific effects. DD estimates of EIP and parity could be used to predict when conditions are suitable for P. vivax transmission.     

Invasive plants in conservation linkages: a conceptual model that addresses an underappreciated conservation issue

Conservationists have frequently touted the merits of increased landscape connectivity, usually focusing on the efficacy of conservation linkages (corridors) for maintaining viable populations of target species. An often‐mentioned, but still greatly understudied, concern is that increased landscape connectivity via linkages may also aid the movement of undesired species. This paper provides conceptual guidance for research on one major aspect of this gap: invasive plants in conservation linkages. To guide research goals and methods, I develop a conceptual model describing eight interaction types between invasive plants and linkages, i.e. the ways that invasive plants can exist in and move into, through, and out of conservation linkages. Each interaction type within the model has three main components: linkage, matrix, and focal species. I discuss several aspects of these components, including a) differentiating among matrix types, b) understanding edge effects within the linkages, and c) incorporating relevant invasive species’ ecology (primarily dispersal ecology). Spatially‐explicit documentation of invasive plant distribution is essential to understanding these interactions. By focusing on landscape‐scale patterns in real‐world systems, this model will enhance landscape‐level knowledge of invasion ecology and aid land managers in identifying and prioritizing research and management decisions regarding invasive plants in conservation linkages.     

Sphingosine-1-phosphate signaling in vasculogenesis and angiogenesis

Blood vessels either form de novo through the process of vasculogenesis or through angiogenesis that involves the sprouting and proliferation of endothelial cells in pre-existing blood vessels. A complex interactive network of signaling cascades downstream from at least three of the nine known G-protein-coupled sphingosine-1-phosphate (S1P) receptors act as a prime effector of neovascularization that occurs in embryonic development and in association with various pathologies. This review focuses on the current knowledge of the roles of S1P signaling in vasculogenesis and angiogenesis, with particular emphasis on vascular cell adhesion and motility responses.