bluuebunny/crossref_metadata_2025 huggingface dataset:
LIPIDS OF CANDIDA UTILIS: CHANGES WITH GROWTH
Authors: Dawson P. S. S. , Craig B. M.
Published: February 2010

Total lipids were extracted from cells of Candida utilis grown in batch, chemostat, and phased culture. Thin-layer chromatography of the extracts showed qualitative changes in the different lipid classes with growth. Gas–liquid chromatography was used to follow quantitative changes in the fatty acid constituents. Changes were found to be analogous to those previously reported for the amino acid pool, i.e., characteristic of the medium, of growth rate, and of the environment. The significance of the changes, and of the methods used to detect them, are discussed in relation to the growth and metabolism of the cell and of the culture.
EFFECTS OF VEGETABLE TANNINS ON GLUCOSE OXIDATION BY VARIOUS MICROORGANISMS
Authors: Basaraba J.
Published: February 2010

The effects of purified tannin preparations of chestnut wood and of wattle bark on the respiration of resting cells of microorganisms were measured in a Warburg apparatus. Tannins were tested at 0.5% (w/v) concentration alone and in mixtures with glucose which provided energy for the microorganisms. In presence of the chestnut and wattle tannins, the exogenous respiration of Asotobacter vinelandii was reduced by 50 and 85% and that of Escherichia coli by 40 and 20%, respectively; respiration of Azatobacler chroococcum was completely inhibited by either tannin. Glucose oxidation by Rhizobium melioti, Rhisobium sp., and Saccharomyces cerevisiae was inhibited by tannins to small degrees. Tannins had no effect on glucose utilization by Rhodotorula sp. and Pseudomonas fluorescens. A. vinelandii, E. coli, and P. fluorescens utilized tannins, especially wattle, as an energy source.
THE PRESENCE OF FLAGELLAR ANTIGEN IN SALMONELLA TYPHI SPHEROPLASTS: IMMUNOCHEMICAL STUDIES
Authors: Sparkes B. G. , Griffiths B. W. , Diena B. B. , Greenberg L.
Published: February 2010

Glycine-induced spheroptasts of Salmonella typhi, while exhibiting very few flagella, contain an antigen which, by gel diffusion tests, is immunologically identical with purified fiagellin (PF) obtained from flagella of S. typhi. The spheroplast flagellar antigen (SpE-FA) amounts to one-fifth the quantity of the normal cell flagellar antigen (NCE-FA) as determined by studies of the inhibition of hemagglutination. On immunoelectrophoresis the SpE-FA has a mobility intermediate between that of the NCE-FA, which moves towards the anode, and that of purified or polymerized flagellin which moves slightly towards the cathode. This could mean that the SpE-FA represents an organization of flagellin molecules intermediate between fully aggregated polymers and unaggregated polymers, or that the SpE-FA has a monomeric unit chemically abnormal because of its synthesis in 1.5% glycine.
NITRIFICATION BY GROWING AND REPLACEMENT CULTURES OF ASPERGILLUS
Authors: Doxtader K. G. , Alexander M.
Published: February 2010

Growing cultures of Aspergillus Jiuvus converted a variety of amino acids, propionamide, malonylmonohydroxamate, 3-nitropropionate (3-NPA), and nitrite to nitrate. Nitrate production was particularly high with L-asparagine and 3-NPA, half the nitrogen of the latter being recovered as nitrate. Many other compounds either failed to enhance or inhibited nitrification. Replacement cultures of the fungus oxidized half the nitrogen of β-alanine or aspartate to nitrate, but ammonium, hydruxylamine, nitrite, or a variety of organic nitrogenous compounds were not nitrified by the hyphal mats. The ability of the fungus to nitrify β-alanine and aspartate but not 3-NPA was lost if the organism was maintained on artificial media. A number of aspergilli excreted nitrate during growth in media containing ammonium or β-alanine. Replacement cultures of the aspergilli did not oxidize ammonium, but most of the fungi produced nitrate from 3-NPA and some oxidized nitrite as well. Hyphal extracts of several of the nitrifying strains formed nitrite but not nitrate from 3-NPA; however, the extracts did not generate nitrate, nitrite, or 3-NPA from ammonium, hydroxylamine, β-alanine, aspartate, asparagine, malonylmonohydroxamate, 3-hydroxyaminopropionic acid, or N-hydroxyaspartate.
INFLUENCE OF CLAY MINERALS ON MICROORGANISMS: II. EFFECT OF VARIOUS CLAY SPECIES, HOMOIONIC CLAYS, AND OTHER PARTICLES ON BACTERIA
Authors: Stotzky G.
Published: February 2010

Respiration of Agrabacterium radwbacter was stimulated most by certain clay minerals of the 2:1 type (montmorillonite, vermiculite, illite, prochlorite, talc). Some 2:1 minerals (pyrophyllite, verrniculite–mica mixtures), 1:1 minerals (kaolinite, halloysite), and a variety of particles which possess some of the characteristics of clay minerals (ion exchangers, polystyrene latex, glass beads, etc.) had relatively little influence on respiration. One mechanism by which clay minerals and other particles stimulated respiration was by maintaining the pH of the environment suitable for sustained growth. This mechanism was dependent on both the initial pH of the systems and the buffering ability of the particles. Studies with homoionic clays showed that stimulation of respiration and maintenance of favorable pH levels was related to the relative basicity of the exchangeable cations on the clays.
PSEUDOMONAS AERUGINOSA BACTERIOPHAGE SD1
Authors: Shargool P. D. , Townsend E. E.
Published: February 2010

A DNA-containing bacteriophage, designated SD1, was isolated from sewage, using strain B71 of Pseudomonas aeruginosa as host. Lysates titering 1 to 2 × 1011plaque-forming units/ml are produced by infecting cultures growing in a defined medium. Highly purified phage preparations were obtained by a procedure involving concentration with ammonium sulfate at pH 8.2, differential centrifugation, and density gradient centrifugation in cesium chloride solution.Electron microscopy revealed a structure possessing a head of regular hexagonal outline, 50 mμ in diameter, and a tail, 6.2 × 188 mμ. The phage contained approximately 2.8 × 10−17 g nitrogen, 8 × 10−18 g of phosphorus, and 1.1 × 10−16 g DNA per plaque-forming unit. Base analysis of SD1 DNA disclosed the presence of equimolar amounts of adenine and thymine and of guanine and cytosine; the latter two comprise 53% of the bases. The thermal denaturation profile of the isolated DNA indicates that SD1 DNA is a highly ordered structure: the guanine and cytosine content as estimated from the temperature of half maximal ultraviolet absorption agrees with that found by chemical analysis of the DNA.
MORPHOLOGICAL DEVELOPMENT OF CHIKUNGUNYA VIRUS
Authors: Chain Marybelle M. T. , Doane Frances W. , McLean D. M.
Published: February 2010

Chikungunya virus was first detected by electron microscopy of primary chick embryo fibroblast cultures 5 hours after inoculation. Two types of particles were observed in the cytoplasm of infected cells, but not in uninoculated cells. The smaller, presumably precursor particles, measured 260 to 280 Å. The larger particles contained dense cores 260 to 280 Å in diameter and outer shells 500 to 560 Å in diameter. In cell lysates stained negatively with phosphotungstic acid 12 and 24 hours after inoculation, virus particles surrounded by fine outer membranes showed diameters of 540 to 580 Å. Infective virus was first detected 5 hours after inoculation and maximum yields of cell-associated and extracellular virus were attained at 8 to 10 hours.
THE ENZYMIC HYDROLYSIS OF CARRAGEENAN BY PSEUDOMONAS CARRAGEENOVORA: PURIFICATION OF A κ-CARRAGEENASE
Authors: Weigl J. , Yaphe W.
Published: February 2010

Enzymes specific for the κ and λ fractions of carrageenan were obtained from the cell-free culture medium of Pseudomonas carrageenovora. These enzymes were concentrated by precipitation with ammonium sulfate and separated by chromatography on hydroxylapatite.The κ-carrageenase was purified to electrophoretic homogeneity by incubation at 35 °C and chromatography on DEAE cellulose. The enzymic hydrolysis of κ-carrageenan was accompanied by a rapid fall in specific viscosity and increase in reducing power. The products were a homologous series of sulfated oligosaccharides with 3-O-(3,6-anhydro-α-D-galactopyranosyl)-D-galactopyranose-4-O-sulfate (neocarrabiose-4-O-sulfate) as the major degradation product, and an enzyme-resistant fraction. The alkali-modified enzyme-resistant fraction was degraded by the κ-carrageenase.
MOUSE-PROTECTIVE ANTIBODIES IN HUMAN SERA AGAINST THE SMITH STRAIN OF STAPHYLOCOCCUS AUREUS
Authors: Warner Peter , Slipetz Willy Kole , Kroeker Johanna
Published: February 2010

We confirmed the widespread occurrence in human sera of antibodies able to protect mice from the lethal effect of the Smith strain of Staphylococcus aureus injected intraperitoneally together with hog gastric mucin. We were unable to demonstrate that the antibody was active against other naturally occurring strains of S. aureus nor did such strains absorb the protective antibody from serum.Repeated passage of two of the above strains of S. aureus in the peritoneal cavities of mice produced more virulent daughter strains. Human sera containing protective antibodies against the Smith strain also protected mice against these daughter strains, but the daughter strains also were unable to absorb the protective antibody from human sera. This suggests the existence in human sera of more than one kind of antibody protective against staphylococci.
RAW MILK AS A SOURCE OF MYCOBACTERIA
Authors: Jones Roosevelt J. , Jenkins Daniel E. , Hsu Katharine H. K.
Published: February 2010

This epidemiological investigation revealed raw milk to be a source of mycobacteria, many of which resembled strains pathogenic for man and other animals. Eighty-three mycobacterial strains were isolated from 77 of 123 raw milk samples. The resemblance of these mycobacteria to known mycobacterial species and groups was as follows: 45, Mycobacterium phlei; 14, M. fortuitum; 1, M. smegmatis; and 23, slow growers (14 scotochromogens and 9 nonchromogens). Certain of the nonchromogenic slow growers may prove to be M. avium or M. bovis upon further bacteriological scrutiny.
THE GLUCOSE UPTAKE KINETICS OF SOME MARINE BACTERIA
Authors: Hamilton R. D. , Morgan K. M. , Strickland J. D. H.
Published: February 2010

The kinetics of glucose uptake by marine microbial populations have been investigated. Pure cultures were used in an attempt to define the conditions affecting uptake kinetics. The use of routine marine microbiological media did not isolate microorganisms capable of responding to the substrate levels that one might expect to find in the ocean, but a chemostat approach was successful in the isolation of such forms. Some factors affecting the uptake of glucose at very low levels were investigated. The kinetic approach with pure cultures has possible application as a bioassay method for substrates in low concentrations in seawater. The ecological significance of the investigation is discussed.
THE TRICARBOXYLIC ACID CYCLE, THE GLYOXYLATE CYCLE, AND THE ENZYMES OF GLUCOSE OXIDATION IN PSEUDOMONAS AERUGINOSA
Authors: Tigerstrom Margaret von , Campbell J. J. R.
Published: February 2010

The enzymes of the glyoxylate cycle, the tricarboxylic acid cycle, glucose oxidation, and hydrogen transport were measured in extracts of Pseudomonas aeruginosa grown with glucose, α-ketoglutarate, or acetate as sole carbon source. The specific activity of isocitritase was increased 25-fold by growth on acetate whereas malate synthetase was increased only 4-fold. All of the enzymes of glucose metabolism, operative at the hexose level, were inducible. The enzymes of the tricarboxylic acid cycle were present under all conditions of growth but extracts from acetate-grown cells contained only one-quarter of the fumarase and pyruvic oxidase activity and half the malate-oxidizing activity of the other extracts. Transhydrogenase, NADH oxidase, and NADPH oxidase activities were similar in each type of extracts. Most of the enzymes were present in the soluble cytoplasm, exceptions being glucose oxidase, succinic dehydrogenase, and NADH oxidase.
ÉTUDE D"UNE LIGNÉE DE CELLULES KB INFECTÉES CHRONIQUEMENT PAR LE VIRUS PARA-INFLUENZAE TYPE 3 : III. PROPORTION DE CELLULES INFECTÉES ET PRODUISANT DU VIRUS
Authors: Daniel Philippe
Published: February 2010

Three lines of KB cells permanently infected by myxovirus para-iufluenzae 3, but established at different times, have been studied to ascertain the proportion of infected or virus-producing cells. This investigation was carried out by (1) determining the infectious centers induced under agar by monodispersed KB.EA cells plated on KB cell monolayers, (2) hemadsorption on single KB.EA cells, (3) immunofluorescence, (4) looking for the infectious character of the KB.EA clones. The data obtained by cloning and immunofluorescence show that each cell contains viral antigen. Only a part of the cells, however, induce infectious centers by the plaque technique or are hemadsorbing.The proportion of hemadsorbing cells and the number of red cells adsorbed by a cell (hemadsorbing ability) are the more important as the KB.EA line is younger. The mitotic cells can hemadsorb like the resting cells. The hemadsorbing ability of each cell is stable during at least 24 hours. The clones exhibit the same stability for observation periods up to 10 days. Furthermore, all cells forming a clone have generally the same hemadsorbing ability.It is concluded that all the cells are infected but that viral production varies considerably from one cell to the other while it remains stable enough in each cell.
BIOASSAY OF SEAWATER: II. METHODS FOR THE DETERMINATION OF CONCENTRATIONS OF DISSOLVED VITAMIN B1 IN SEAWATER
Authors: Carlucci A. F. , Silbernagel S. B.
Published: February 2010

Methods for the bioassay of seawater for vitamin B1 (thiamine) using the marine chrysomonad, Monochrysis lutheri, are described. Cell counts after a 120-hour incubation or 14C-uptake rates after a 48- or 72-hour incubation were proportional to the vitamin B1 concentrations in seawater. Samples of seawater were supplemented with nutrients, filter-sterilized, and, if necessary, diluted with medium prepared in charcoal-treated seawater. External and internal standards were used. A starved culture of M. lutheri was added and the assay-flasks were incubated in the light for 46 or 70 hours, after which 14C as Na214CO3 was added and its uptake was measured after 2 hours. Cell counts were made after 120 hours. Most of the samples bioassayed to date showed no inhibition to the alga. The range of vitamin B1 concentrations which can be assayed was about 2–35 ng/l by 46-hour preincubation followed by 14C-uptake measurements or by counting cells after 120 hours. The range was extended to 100 ng B1/l after the 70-hour preincubation in the 14C-uptake method. These methods were capable of determining vitamin B1 in seawater at about one-tenth the level reported previously.
THE INACTIVATION OF PERTUSSIS PROTECTIVE ANTIGEN, HISTAMINE SENSITIZING FACTOR, AND LIPOPOLYSACCHARIDE BY SODIUM METAPERIODATE
Authors: Wardlaw A. C. , Jakus Cvetka M.
Published: February 2010

The mouse protective antigen (MPA) and histamine-sensitizing factor (HSF) in sonic extracts of B. pertussis resembled one another in being much less sensitive to destruction by sodium periodate at 1 °C than was the serological activity of the pertussis lipopolysaccharide (LP). Whereas the latter was more than 96% inactivated by 2 hours in 0.01 M periodate at pH 7.4 at 1°, MPA and HSF underwent, on average, 48% and 32% inactivation respectively. Glucose and serine similarly treated with periodate were completely oxidized; trypsin underwent 44% inactivation, but insulin, tetanus toxin, and the peptide cystinyldiglycine were not significantly attacked. These results are interpreted as supporting the view that MPA and HSF probably do not contain functionally essential carbohydrate and, from this and other evidence, are probably protein in nature.
UPTAKE OF ORGANIC AND INORGANIC RADIOACTIVE SUBSTANCES AND MULTIPLICATION OF MYCOBACTERIUM LEPRAE MURIUM ON ALKALINE GALACTOMANNAN MEDIUM
Authors: Ghys R. , Gözsy B. , Kátó L.
Published: February 2010

A limited multiplication of Mycobacterium leprae murium occurred in an alkaline galactomannan medium. Multiplication was enhanced by parabiosis with Torula minuta cells. 59Fe uptake was proportional to the rate of multiplication and dependent on the pH and NaCl concentration as well as on the amount of Fe in the medium; however, 65Zn uptake is independent of Zn concentration up to a concentration of 10 mg Zn/l. Glucose (14C1, 14C6), asparagine, glycerol, and histamine were not adsorbed by the bacilli in significant amounts. The authors discuss the usefulness of measurements of 59Fe uptake for studies of the nutrients that can be used by this noncultivable microorganism, and those that are essential for its multiplication.
SPORE GERMINATION AND VEGETATIVE GROWTH OF CLOSTRIDIUM BOTULINUM TYPE E IN SYNTHETIC MEDIA
Authors: Ward B. Q. , Carroll B. J.
Published: February 2010

A synthetic medium supporting growth of Clostridium botulinum type E, strain D8, from spore inocula was devised. The effects of single amino acid deletions or additions were studied. Certain of these were inhibitory, but none completely suppressed germination or subsequent vegetative growth. Spore germinations in solutions of single amino acids were also studied. Germination in some of these was delayed but it did occur in all cases.The effects of single vitamin omissions were followed from spore germination to growth maxima. Such deletions were essentially ineffectual.Additions of nucleic acids to the medium were somewhat stimulatory. Early growth curves approximated controls but maxima were superior to those of controls. The addition of purine or pyrimidine bases or pentose sugars did not greatly influence growth. Thymine or deoxyribose delayed spore germination.Additions of selected acids associated with lipids, or currently or historically with food preservation, were often detrimental but never completely inhibitory. The addition of citric and (or) lactic acid to the medium permitted toxin formation.
REGULATION OF PROTEINASE FORMATION IN A SPECIES OF MICROCOCCUS
Authors: McDonald I. J. , Chambers Alice K.
Published: February 2010

Micrococcus sp. ATCC No. 407 (M. freudenreichii) produced relatively large amounts of extracellular proteinase in synthetic medium containing methionine, thiamine, biotin, NH4Cl, NaHCO3, NaCl, MgSO4, and FeSO4, with aspartic acid, asparagine, glutamic acid, or glutamine as the carbon source. The organism produced relatively small amounts of proteinase with succinate, malate, fumarate, maltose, maltotriose, or maltotetraose as the carbon source. In synthetic medium containing maltose, any one of several amino acids stimulated growth and proteinase production. The results indicated that the organism is a partial constitutive strain with respect to proteinase production and suggested that proteinase formation is controlled by a form of end-product induction. In the presence of inducer, carbon sources such as succinate or maltose caused suppression of proteinase formation, suggesting control by metabolic repression as well. Because extracellular proteinase formation is induced by amino acids and suppressed by carbon sources such as succinate or maltose, and because the organism can utilize amino acids as carbon sources for growth, it. is suggested that the function of extracellular proteinase in this organism is to ensure a supply of carbon for growth rather than a supply of amino acids for protein synthesis.
THE BIOLOGICAL PROPERTIES OF 3,6-EPIDITHIADIKETOPIPERAZINES: INHIBITION OF GROWTH OF BACILLUS SUBTILIS BY GLIOTOXINS, SPORIDESMINS, AND CHETOMIN
Authors: Brewer D. , Hannah D. E. , Taylor A.
Published: February 2010

The ability of chetomin and the sporidesmin and gliotoxin groups of fungal metabolites to inhibit the growth of Bacillus subtilis (HLX 373) has been examined. With the exception of gliotoxin dibenzoate, compounds having the 3,6-epidithiadiketopiperazine structure, when added to the culture medium before inoculation, increased the lag phase of growth; this increase was influenced by the number of organisms in the inoculum and the concentration of the metabolite. When the disulfide bridge was eliminated chemically, the resulting degradation products were biologically inactive.
COMPARISON OF NICOTINAMIDE ADENINE DINUCLEOTIDE SYNTHESIS BY MYCOBACTERIUM TUBERCULOSIS AND MYCOBACTERIUM BOVIS
Authors: Dudley Mary A. , Willett Hilda Pope
Published: February 2010

The R1Rvstrain of M. tuberculosis utilized nicotinic acid for the synthesis of nicotinamide adenine dinucleotide (NAD). Nicotinic acid mononucleotide (NaMN) and nicotinic acid dinucleotide (NaAD) were identified among the enzymatic reaction mixture products. A comparison with M. bovis demonstrated a greater capacity for NAD synthesis by the bovine bacillus. It has been hypothesized that reduced NAD synthesis and failure to utilize intermediates which continue to be produced are responsible for the excessive nicotinic acid accumulation by M. tuberculosis.
GLUTACONIC ACID, A PRODUCT OF THE FERMENTATION OF GLUTAMIC ACID BY PEPTOGOCCUS AEROGENES
Authors: Horler D. F. , McConnell W. B. , Westlake D. W. S.
Published: February 2010

Radioactive glutaconic acid was isolated from reaction mixtures in which Peptococcus aerogenes fermented glutamic acid-2-14C. The infrared spectrum, X-ray diffraction pattern, and melting point of the biologicai product is identical with that of chemically synthesized glutaconic acid. Cells of P. aerogenes fermented glutaconic acid, although at low rate, producing acetic and butyric acid. A possible role for glutaconic acid in the fermentation of glutamic acid is presented.
FUNGI ASSOCIATED WITH LEGUME ROOT NODULES AND THEIR EFFECT ON RHIZOBIA
Authors: Chhonkar P. K. , Subba-Rao N. S.
Published: February 2010

Fungi associated with the nodules of nine common legumes were isolated and identified. The nodules had a mycoflora consisting of Cephalosporium, Alternaria, Aspergillus, Penicillium, Rhizopus, Acrothecium, Fusarium, Rhizoctonia, Curvularia, Pythium, and Trichoderma. Mycoflora of nodules of Trifolium alexandrinum was also analyzed in relation to the age of the plant and the volume of nodules. The fungi were screened for antibiotic activity towards six species of rhizobia. The results showed that Rhizobium trifolii, Rhizobium phaseoli, Rhizobium leguminosarum, and Rhizobium japonicum were relatively more susceptible to fungal antibiotics than either Rhizobium meliloti or Rhizobium sp. (cowpea group). Mycocolonization in soil by an isolate of Cephalosporium sp. significantly reduced the fresh weight and nitrogen status of T. alexandrinum.
THE ANTIMICROBIAL ACTIVITIES OF CARBONYL AND THIOCARBAMOYL DISULFIDES
Authors: Buckman J. D. , Johnson B. S. , Field L.
Published: February 2010

Thirteen unsymmetrical disulfides of the structure —C(=X)SS—, where X is O or S, were evaluated for bactericidal and fungistatic activity under conditions simulating an industrial environment. Some carbonyl disulfides, RC(O)SSR′, were active fungistatic agents and promising bactericides. Some of the thiocarbamoyl disulfides, R2NC(S)SSR′, were found to be promising fungistatic agents and also showed significant bactericidal activity. Correlations of biological activity with chemical properties are discussed.
METABOLISM OF D-TRYPTOPHAN BY A SPECIES OF FLAVOBACTERIUM
Authors: Martin Jerry R. , Durham Norman N.
Published: February 2010

D-Tryptophan can be utilized by a species of Flavobacterium but growth of this bacterium was very slow when D-trytophan was used as the sole carbon and energy source. The addition of other exogenous carbon sources facilitated the utilization of D-tryptophan. The growth yield was less per unit of D-tryptophan than with an equimolar concentration of DL- or L-tryptophan. D-Tryptophan was catabolized via indolepyruvic acid, L-tryptophan, N-formyl-L-kynurenine, L-kynurenine, and anthranilic acid. The organism did not possess a tryptophan racemase. D-Tryptophan was oxidatively deaminated to indolepyruvic acid which was transaminated to form L-tryptophan with L-glutamic acid, L-aspartic acid, or L-glutamine serving as the amino donor. The oxidation as well as the accumulation of anthranilic acid in the medium from D-tryptophan was slower than when L-tryptophan was the substrate. Both the production and utilization of the anthranilic acid formed during the dissimilation of D- or L-tryptophan were suppressed by N-rnethylanthranilic acid.
Nest-site materials affect nest-bowl use by Common Eiders (Somateria mollissima)
Authors: Fast Peter L.F. , Gilchrist H. Grant , Clark Robert G.
Published: February 2010

Nest-site characteristics influence reproductive success in birds. Most studies of nest-site selection evaluate nest characteristics following the commencement of egg-laying, possibly overlooking the importance of pre-existing nest-site features that may be altered during the nesting process. Because Common Eiders ( Somateria mollissima (L.,1758)) often lay their eggs in nest bowls created in previous years, we were able to experimentally place moss or feather down in nest bowls prior to nesting. We then quantified whether these materials increased nest establishment or advanced laying dates relative to control nests and nests where material was removed prior to arrival of nesting females. We found no difference in the likelihood of successful nest establishment between groups. However, the onset of incubation occurred 2–3 days earlier in nest bowls that contained feather down versus nest bowls with little or no nesting material. Nest bowls containing feathers or vegetation may be selected first if they increase nest survival, perhaps by enhancing egg concealment during the critical early-laying period. The presence of material for egg concealment may be particularly important in nesting environments where tall or dense vegetation is not available to provide nest cover.
Trophic relationships of breeding Red-necked Grebes (Podiceps grisegena) on wetlands with and without fish in the Aspen Parkland
Authors: McParland C. E. , Paszkowski C. A. , Newbrey J. L.
Published: February 2010

Dietary overlap between waterbirds and fish in many freshwater systems can lead to competition for food resources and changes in the trophic position of top predators. We used stable isotope analysis of carbon and nitrogen from egg tissues to document differences in the trophic position of breeding Red-necked Grebes ( Podiceps grisegena (Boddaert, 1783)) on wetlands with and without fish in the Aspen Parkland of Alberta, Canada. Grebes occupied higher trophic levels in the presence of fish than in their absence, suggesting that small-bodied fish in Aspen Parkland food webs may lengthen food chains in which grebes are top predators. A mixed diet of invertebrates and fishes may be adaptive for grebes in this highly variable ecosystem where fish colonize wetlands in wet years and are extirpated in dry years. Carbon analyses indicated that female grebes likely obtained resources for egg production from breeding sites and not from wintering areas, as eggs had similar δ13C values to wetland primary producers, invertebrates, and fishes.
Does food abundance explain altitudinal migration in a tropical frugivorous bird?
Authors: Boyle W. A.
Published: February 2010

Many animals undergo annual migrations. These movements are well studied at proximate levels, but their fundamental causes are poorly understood. Among tropical frugivorous birds, annual migration is thought to have evolved in the context of exploiting reciprocal peaks in fruit abundance among locations and seasons, yet previous tests of this hypothesis have yielded equivocal results. In this paper, I tested whether protein and (or) fruit limitation explain both uphill and downhill migratory movements in a tropical frugivorous bird, the White-ruffed Manakin ( Corapipo altera Hellmayer, 1906). While White-ruffed Manakins likely migrate uphill to exploit peaks in fruit abundance, I found no evidence that elevational differences in fruit abundance explain the downhill portion of the migratory cycle. This result challenges long-standing ideas regarding the causes of altitudinal migration because it implies that birds seeking to maximize fruit intake should remain sedentary at higher elevations. Data are also inconsistent with the hypothesis that White-ruffed Manakins migrate (either uphill or downhill) to exploit arthropod prey. Future studies should consider how variation in weather, predators, or parasites could help explain altitudinal migrations of birds from breeding areas to nonbreeding areas.
Cross-seasonal dynamics in body mass of male Harlequin Ducks: a strategy for meeting costs of reproduction
Authors: Esler Daniel , Bond Jeanine C.
Published: February 2010

Considerations of acquisition of energy for reproduction by waterfowl have disproportionately focused on females, although males also require energy for reproduction. We quantified variation in body mass of male Harlequin Ducks ( Histrionicus histrionicus (L., 1758)) on coastal wintering areas prior to spring migration, as well as on breeding grounds, to determine when and where nutrients were acquired to meet costs of reproduction. Male mass on wintering grounds increased, on average, by 45 g (7%) in the weeks prior to migration. On breeding streams, we inferred that body mass of paired males decreased with the length of time on breeding grounds. Also, on average, male mass was considerably lower on breeding streams than when they departed coastal wintering sites. We conclude that males store nutrients on marine wintering grounds for subsequent use during the breeding season. Male Harlequin Ducks are highly vigilant while on breeding streams and the associated reduction in feeding time presumably requires energy stores. We suggest that males have evolved a strategy that is at least partially “capital” for meeting costs of reproduction, in which they acquire an optimal amount of energy reserves prior to spring migration and subsequently invest them in behaviours that can enhance reproductive success.
Influence of patch- and landscape-level attributes on the movement behavior of raccoons in agriculturally fragmented landscapes
Authors: Beasley J. C. , Rhodes O. E.
Published: February 2010

We tested the hypotheses that movement rates and home range sizes of raccoons ( Procyon lotor (L., 1758)) inhabiting a highly fragmented landscape would vary in response to local and landscape-level habitat characteristics. Raccoons occupying small forest patches containing limited water sources maintained larger home ranges than raccoons with home ranges established in large forest patches containing abundant sources of water. Raccoons occupying large (>25 ha) forest patches exhibited minimal interindividual variance in home range size compared with raccoons monitored in patches <25 ha. This differing pattern of variance in home range size suggests that critical resources were more widely dispersed within and among small patches, forcing raccoons occupying smaller patches to utilize larger and more spatially disparate areas to satisfy their metabolic and reproductive needs. Movement rates of raccoons were positively related to home range size, although movement rates of males (246.9 m/h) exceeded those of females (188.3 m/h). Moreover, movements of male raccoons primarily were concentrated along forest–agriculture interfaces, whereas female movements were concentrated in forest interiors. Our results indicate that raccoons have modified their movement behavior in agricultural ecosystems in response to the discontinuous nature of resources and suggest that the extent of raccoon space use in these ecosystems is strongly influenced by the availability of non-agricultural resources.
The relative effects of mating status and age on the mating behaviour of female field crickets
Authors: Judge Kevin A. , Tran Kim-Chi , Gwynne Darryl T.
Published: February 2010

Intrinsic factors such as female age and mating status have been found to affect female choosiness. However, as these factors are often confounded in the wild because mated females are usually older individuals, the relative influence of these two factors on female behaviour is unclear. Using a fully factorial design, we tested the relative effects of age and mating status of female field crickets ( Gryllus pennsylvanicus Burmeister, 1838) on both (i) the probability that she would mate and (ii) her latency to mate. We found that virgin females were both more likely to mate and copulated more quickly than mated females, but female age had no significant effect on either the probability of mating or the latency to copulate. These results clearly show that mating status is more important in determining female mating behaviour than age. We suggest that previous work which showed an age effect on female choosiness in virgins alone might be of reduced relevance if most females do not remain unmated for long.
Insulin-like growth factors are more effective than progastrin in reversing proapoptotic effects of curcumin: critical role of p38MAPK
Authors: Singh Pomila , Sarkar Shubhashish , Umar Shahid , Rengifo-Cam William , Singh Amar P. , Wood Thomas G.
Published: February 2010

Progastrin and insulin-like growth factors (IGFs) stimulate hyperproliferation of intestinal epithelial cells (IECs) via endocrine/paracrine routes; hyperproliferation is a known risk factor for colon carcinogenesis. In the present study, inhibitory potency of curcumin in the presence or absence of progastrin and/or IGF-II was examined. Progastrin and IGF-II significantly increased proliferation of an immortalized IEC cell line, IEC-18, whereas curcumin decreased the proliferation in a dose-dependent manner. IGF-II was significantly more effective than progastrin in reversing antiproliferative effects of curcumin and reversed proapoptotic effects of curcumin by >80%; progastrin was relatively ineffective toward reversing proapoptotic effects of curcumin. IEC-18 clones were generated to overexpress either progastrin (IEC-PG) or hIGF-II (IEC-IGF). Proliferation of IEC-PG and IEC-IGF clones was increased, compared with that of control clones. Curcumin significantly reduced proliferation of IEC-PG, but not IEC-IGF, clones. Similarly, a human colon cancer cell line, Caco-2 (which expresses autocrine IGF-II), was relatively resistant to inhibitory effects of curcumin. However, Caco-2 cells treated with anti-IGF-II-antibodies were rendered sensitive to inhibitory effects of curcumin. Significant differences in inhibitory potency of curcumin against PG- vs. IGF-II-stimulated growth of IEC-18 cells were not reflected by differences in curcumin-mediated inhibition of activated (phosphorylated) ERKs/IKKα/β/p65NF-κB and c-Src in wild-type (wt)IEC-18 cells, in response to the two growth factors. Surprisingly, curcumin was almost ineffective in reducing IGF-II-stimulated activation of p38MAPK but significantly reduced progastrin-stimulated phosphorylation of p38. Treatment with a p38MAPK inhibitor resulted in loss of protective effects of IGF-II against inhibitory effects of curcumin. These novel findings suggest that growth factor profile of patients and tumors may dictate inhibitory potency of curcumin and that combination of curcumin + p38MAPK inhibitor may be required for reducing hyperproliferative or tumorigenic response of IECs to endocrine and autocrine IGFs.
Hypoxia-induced proliferation of human pulmonary microvascular endothelial cells depends on epidermal growth factor receptor tyrosine kinase activation
Authors: Toby Inimary T. , Chicoine Louis G. , Cui Hongmei , Chen Bernadette , Nelin Leif D.
Published: February 2010

We hypothesized that hypoxia would activate epidermal growth factor receptor (EGFR) tyrosine kinase, leading to increased arginase expression and resulting in proliferation of human pulmonary microvascular endothelial cell (hPMVEC). To test this hypothesis, hPMVEC were incubated in normoxia (20% O2, 5% CO2) or hypoxia (1% O2, 5% CO2). Immunoblotting for EGFR and proliferating cell nuclear antigen was done, and protein levels of both total EGFR and proliferating cell nuclear antigen were greater in hypoxic hPMVEC than in normoxic hPMVEC. Furthermore, hypoxic hPMVEC had greater levels of EGFR activity than did normoxic hPMVEC. Hypoxic hPMVEC had a twofold greater level of proliferation compared with normoxic controls, and this increase in proliferation was prevented by the addition of AG-1478 (a pharmacological inhibitor of EGFR). Immunoblotting for arginase I and arginase II demonstrated a threefold induction in arginase II protein levels in hypoxia, with little change in arginase I protein levels. The hypoxic induction of arginase II protein was prevented by treatment with AG-1478. Proliferation assays were performed in the presence of arginase inhibitors, and hypoxia-induced proliferation was also prevented by arginase inhibition. Finally, treatment with an EGFR small interfering RNA prevented hypoxia-induced proliferation and urea production. These findings demonstrate that hypoxia activates EGFR tyrosine kinase, leading to arginase expression and thereby promoting proliferation in hPMVEC.
Serotonergic projection from nucleus raphe pallidus to rostral ventrolateral medulla modulates cardiovascular reflex responses during acupuncture
Authors: Moazzami Ali , Tjen-A-Looi Stephanie C. , Guo Zhi-Ling , Longhurst John C.
Published: February 2010

We have demonstrated that stimulation of somatic afferents during electroacupuncture (EA) inhibits sympathoexcitatory cardiovascular rostral ventrolateral medulla (rVLM) neurons and reflex responses. Furthermore, EA at P5-P6 acupoints over the median nerve on the forelimb activate serotonin (5-HT)-containing neurons in the nucleus raphe pallidus (NRP). The present study, therefore, examined the role of the NRP and its synaptic input to neurons in the rVLM during the modulatory influence of EA. Since serotonergic neurons in the NRP project to the rVLM, we hypothesized that the NRP facilitates EA inhibition of the cardiovascular sympathoexcitatory reflex response through activation of 5-HT1Areceptors in the rVLM. Animals were anesthetized and ventilated, and heart rate and blood pressure were monitored. We then inserted microinjection and recording electrodes in the rVLM and NRP. Application of bradykinin (10 μg/ml) on the gallbladder every 10 min induced consistent excitatory cardiovascular reflex responses. Stimulation with EA at P5-P6 acupoints reduced the increase in blood pressure from 41 ± 4 to 22 ± 4 mmHg for more than 70 min. Inactivation of NRP with 50 nl of kainic acid (1 mM) reversed the EA-related inhibition of the cardiovascular reflex response. Similarly, blockade of 5-HT1Areceptors with the antagonist WAY-100635 (1 mM, 75 nl) microinjected into the rVLM reversed the EA-evoked inhibition. In the absence of EA, NRP microinjection of dl-homocysteic acid (4 nM, 50 nl), to mimic EA, reduced the cardiovascular and rVLM neuronal excitatory reflex response during stimulation of the gallbladder and splanchnic nerve, respectively. Blockade of 5-HT1Areceptors in the rVLM reversed the NRP dl-homocysteic acid inhibition of the cardiovascular and neuronal reflex responses. Thus activation of the NRP, through a mechanism involving serotonergic neurons and 5-HT1Areceptors in the rVLM during somatic stimulation with EA, attenuates sympathoexcitatory cardiovascular reflexes.
Proximal tibia volumetric bone mineral density is correlated to the magnitude of local acceleration in male long-distance runners
Authors: Dériaz Olivier , Najafi Bijan , Ballabeni Pierluigi , Crettenand Antoinette , Gobelet Charles , Aminian Kamiar , Rizzoli René , Gremion Gerald
Published: February 2010

The beneficial effect of physical exercise on bone mineral density (BMD) is at least partly explained by the forces exerted directly on the bones. Male runners present generally higher BMD than sedentary individuals. We postulated that the proximal tibia BMD is related to the running distance, as well as to the magnitude of the shocks (while running) in male runners. A prospective study (three yearly measurements) included 81 healthy male subjects: 16 sedentary lean subjects, and 3 groups of runners (5–30 km/wk, n = 19; 30–50 km/wk, n = 29; 50–100 km/wk, n = 17). Several measurements were performed at the proximal tibia level: volumetric BMD (vBMD) and cortical index (CI), i.e., an index of cortical bone thickness and peak accelerations (an index of shocks during heel strike) while running (measured by a three-dimensional accelerometer). A general linear model assessed the prediction of vBMD or CI by 1) simple effects (running distance, peak accelerations, time); and 2) interactions (for instance, if vBMD prediction by peak acceleration depends on running distance). CI and vBMD 1) increase with running distance to reach a plateau over 30 km/wk; and 2) are positively associated with peak accelerations over 30 km/wk. Running may be associated with high peak accelerations to have beneficial effects on BMD. More important strains are needed to be associated with the same increase in BMD during running sessions of short duration than those of long duration. CI and vBMD are associated with the magnitude of the shocks during heel strike in runners.
Why has reversal of the actin-myosin cross-bridge cycle not been observed experimentally?
Authors: Loiselle Denis S. , Tran Kenneth , Crampin Edmund J. , Curtin Nancy A.
Published: February 2010

We trace the history of attempts to determine whether the experimentally observed diminution of metabolic energy expenditure when muscles lengthen during active contraction is consistent with reversibility of biochemical reactions and, in particular, with the regeneration of ATP. We note that this scientific endeavor has something of a parallel flavor to it, with both early and more recent experiments exploiting both isolated muscle preparations and exercising human subjects. In tracing this history from the late 19th century to the present, it becomes clear that energy can be (at least transiently) stored in a muscle undergoing an eccentric contraction but that this is unlikely to be due to the regeneration of ATP. A recently developed, thermodynamically constrained model of the cross-bridge cycle provides additional insight into this conclusion.
Disruption of BCAA metabolism in mice impairs exercise metabolism and endurance
Authors: She Pengxiang , Zhou Yingsheng , Zhang Zhiyou , Griffin Kathleen , Gowda Kavitha , Lynch Christopher J.
Published: February 2010

Exercise enhances branched-chain amino acid (BCAA) catabolism, and BCAA supplementation influences exercise metabolism. However, it remains controversial whether BCAA supplementation improves exercise endurance, and unknown whether the exercise endurance effect of BCAA supplementation requires catabolism of these amino acids. Therefore, we examined exercise capacity and intermediary metabolism in skeletal muscle of knockout (KO) mice of mitochondrial branched-chain aminotransferase (BCATm), which catalyzes the first step of BCAA catabolism. We found that BCATm KO mice were exercise intolerant with markedly decreased endurance to exhaustion. Their plasma lactate and lactate-to-pyruvate ratio in skeletal muscle during exercise and lactate release from hindlimb perfused with high concentrations of insulin and glucose were significantly higher in KO than wild-type (WT) mice. Plasma and muscle ammonia concentrations were also markedly higher in KO than WT mice during a brief bout of exercise. BCATm KO mice exhibited 43–79% declines in the muscle concentration of alanine, glutamine, aspartate, and glutamate at rest and during exercise. In response to exercise, the increments in muscle malate and α-ketoglutarate were greater in KO than WT mice. While muscle ATP concentration tended to be lower, muscle IMP concentration was sevenfold higher in KO compared with WT mice after a brief bout of exercise, suggesting elevated ammonia in KO is derived from the purine nucleotide cycle. These data suggest that disruption of BCAA transamination causes impaired malate/aspartate shuttle, thereby resulting in decreased alanine and glutamine formation, as well as increases in lactate-to-pyruvate ratio and ammonia in skeletal muscle. Thus BCAA metabolism may regulate exercise capacity in mice.
Using molecular classification to predict gains in maximal aerobic capacity following endurance exercise training in humans
Authors: Timmons James A. , Knudsen Steen , Rankinen Tuomo , Koch Lauren G. , Sarzynski Mark , Jensen Thomas , Keller Pernille , Scheele Camilla , Vollaard Niels B. J. , Nielsen Søren , Åkerström Thorbjörn , MacDougald Ormond A. , Jansson Eva , Greenhaff Paul L. , Tarnopolsky Mark A. , van Loon Luc J. C. , Pedersen Bente K. , Sundberg Carl Johan , Wahlestedt Claes , Britton Steven L. , Bouchard Claude
Published: February 2010

A low maximal oxygen consumption (V̇o2max) is a strong risk factor for premature mortality. Supervised endurance exercise training increases V̇o2max with a very wide range of effectiveness in humans. Discovering the DNA variants that contribute to this heterogeneity typically requires substantial sample sizes. In the present study, we first use RNA expression profiling to produce a molecular classifier that predicts V̇o2max training response. We then hypothesized that the classifier genes would harbor DNA variants that contributed to the heterogeneous V̇o2max response. Two independent preintervention RNA expression data sets were generated ( n = 41 gene chips) from subjects that underwent supervised endurance training: one identified and the second blindly validated an RNA expression signature that predicted change in V̇o2max (“predictor” genes). The HERITAGE Family Study ( n = 473) was used for genotyping. We discovered a 29-RNA signature that predicted V̇o2max training response on a continuous scale; these genes contained ∼6 new single-nucleotide polymorphisms associated with gains in V̇o2max in the HERITAGE Family Study. Three of four novel candidate genes from the HERITAGE Family Study were confirmed as RNA predictor genes (i.e., “reciprocal” RNA validation of a quantitative trait locus genotype), enhancing the performance of the 29-RNA-based predictor. Notably, RNA abundance for the predictor genes was unchanged by exercise training, supporting the idea that expression was preset by genetic variation. Regression analysis yielded a model where 11 single-nucleotide polymorphisms explained 23% of the variance in gains in V̇o2max, corresponding to ∼50% of the estimated genetic variance for V̇o2max. In conclusion, combining RNA profiling with single-gene DNA marker association analysis yields a strongly validated molecular predictor with meaningful explanatory power. V̇o2max responses to endurance training can be predicted by measuring a ∼30-gene RNA expression signature in muscle prior to training. The general approach taken could accelerate the discovery of genetic biomarkers, sufficiently discrete for diagnostic purposes, for a range of physiological and pharmacological phenotypes in humans.
Rho Signaling and Tight Junction Functions
Authors: Terry Steve , Nie Mei , Matter Karl , Balda Maria S.
Published: February 2010

Tight junctions are heteromeric protein complexes that act as signaling centers by mediating the bidirectional transmission of information between the environment and the cell interior to control paracellular permeability and differentiation. Insight into tight junction-associated signaling mechanisms is of fundamental importance for our understanding of the physiology of epithelia and endothelia in health and disease.
Voltage-Gated Proton Channels Find Their Dream Job Managing the Respiratory Burst in Phagocytes
Authors: DeCoursey Thomas E.
Published: February 2010

The voltage-gated proton channel bears surprising resemblance to the voltage-sensing domain (S1–S4) of other voltage-gated ion channels but is a dimer with two conduction pathways. The proton channel seems designed for efficient proton extrusion from cells. In phagocytes, it facilitates the production of reactive oxygen species by NADPH oxidase.