bluuebunny/crossref_metadata_2025 huggingface dataset:
Solubilization of microsomal-associated phosphatidylserine synthase and phosphatidylinositol synthase from Saccharomyces cerevisiae
Authors: Carman George M. , Matas Jonathan
Published: May 2010

Membrane-associated cytidine 5′-diphospho-1,2-diacyl-sn-glycerol (CDP-diacylglycerol):L-serine O-phosphatidyltransferase (phosphatidylserine synthase, EC 2.7.8.8.) and CDP-diacylglycerol: myo-inositol phosphatidyltransferase (phosphatidyl-inositol synthase, EC 2.7.8.11) were solubilized from the microsomal fraction of Saccharomyces cerevisiae. A variety of detergents were examined for their ability to release phosphatidylserine synthase and phosphatidylinositol synthase activities from the microsome fraction. Both enzymes were solubilized from the microsome fraction with Renex 690 in yields over 80% with increases in specific activity of 1.6-fold. Both solubilized enzymatic activities were dependent on manganese ions and Triton X-100 for maximum activity. The pH optimum for each reaction was 8.0. The apparent Km values for CDP-diacylglycerol and serine for the phosphatidylserine synthase reaction were 0.1 and 0.25 mM, respectively. The apparent Km values for CDP-diacylglycerol and inositol for the phosphatidylinositol synthase reaction were 70 μM and 0.1 mM, respectively. Thiore-active agents inhibited both enzymatic activities. Both solubilized enzymatic activities were thermally inactivated at temperatures above 30 °C.
Cytological responses of Cladosporium resinae when shifted from glucose to hydrocarbon medium
Authors: Smucker R. A. , Cooney J. J.
Published: May 2010

Cladosporium resinae was grown on glucose and then transferred to medium with glucose or with kerosene as the sole carbon source. Growth on hydrocarbon was associated with thinner cell walls in both hyphae and spores, with the presence of large vacuoles in cells, with the synthesis of microbodies, and with increased synthesis of catalase. Some vacuoles in hydrocarbon-grown cells contained small, spherical, electron-dense inclusions which were not observed in cells from glucose medium. Large, electron-dense bodies within vacuoles were observed in glucose-grown and in hydrocarbon-grown cells. A working model is proposed for oxidation of n-alkanes by C. resinae.
Antibodies to the California group of arboviruses in the moose (Alces alces americana Clinton) population of Nova Scotia
Authors: McFarlane B. L. , Embil J. A. , Artsob H. , Spence L. , Rozee K. R.
Published: May 2010

Moose (Alces alces americana Clinton) blood collected by hunters during the 1977 and 1978 hunting seasons was tested for California group antibodies. Hemagglutination inhibition (HI) tests using snowshoe hare virus (SSH) as antigen yielded 37.02% HI-positive sera. Neutralization tests showed reactors (67.5% positive) to SSH and classified six reactors as Jamestown Canyon virus (JC). This study reports the first finding of JC in a moose population; it also provides the first evidence of JC in Atlantic Canada and supports previous findings of SSH in Nova Scotia.
Characterization and cyst production of azospirilla isolated from selected grasses growing in New Jersey and New York
Authors: Lamm Robert B. , Neyra Carlos A.
Published: May 2010

Species of Azospirillum were readily isolated from the roots of several grasses growing under a wide range of conditions in the New Jersey – New York area. The number of successful isolations from corn, rice, zoysia, and reed roots was relatively high (up to 87%). Based upon morphological and physiological characterization, six of the isolates appeared to be Azopirillum brasilense sp. nov., while two isolates more closely resembled Azospirillum lipoferum (Beijerinck) comb. nov. When grown in semisolid malate medium, the cells averaged 1.5 μm in diameter and ranged from 3 to 30 μm in length. Formation of larger S-shaped vegetative cells was evident only in A. lipoferum, but most important was the pleomorphism which was displayed by all isolates, as well as the reference cultures for A. lipoferum and A. brasilense. Upon prolonged incubation in semisolid and solid media, all isolates, as well as the reference cultures, produced thick-walled, cystlike ovoid structures which were quite distinct from the typical vibrioid or S-shaped cell morphology of this genus. Cysts were approximately 2.5 μm in diameter and from 3 to 15 μm in length. Cyst-enriched cultures were much more resistant to desiccation than normal vegetative cultures. Production of cysts may thus represent a mechanism by which azospirilla can persist in the rhizosphere during unfavorable environmental conditions.
Growth of group E streptococci and production of antigens in a chemically defined medium
Authors: Wessman G. E.
Published: May 2010

Group E streptococci were grown in a modification of a chemically defined medium (CDM) originally formulated for streptococci of group A. Ten of 12 strains studied produced greater or equal cultural densities and growth rates in CDM than in the complex medium (Todd–Hewitt broth). All strains produced similar amounts of group antigen in both media. Eight strains of demonstable serotype produced comparable amounts of type antigen in both media. Cells grown in CDM were less resistant to phagocytosis than those grown in the complex medium, but all strains produced antiphagocytic factor when cultured in either medium to which 10% porcine serum had been added.
Seasonal distribution of bdellovibrios at the mouth of the Patuxent River in the Chesapeake Bay
Authors: Williams Henry N. , Falkler Jr. William A. , Shay Donald E.
Published: May 2010

Water samples taken at monthly intervals from three sites in the mouth of the Patuxent River in the Chesapeake Bay were cultured for bdellovibrios lytic to Vibrio parahaemolyticus and for total viable bacterial counts. The number of bdellovibrios recovered decreased from the spring months (April, May, June (AMJ)) until very few were detected during the winter months (January, February, March (JFM)), which also coincided with the lowest water temperatures. During the AMJ season there was a significant increase as compared with the JFM season in the number of bdellovibrios for all sites. The highest number of bdellovibrios was recovered during each season from the shoreline water sample, with one exception. The seasonal variation in the number of bdellovibrios was observed to correlate statistically with the water temperature.
The biodegradation of methoxychlor by Klebsiella pneumoniae
Authors: Baarschers William H. , Bharath Ainsley I. , Elvish Jaquie , Davies Michael
Published: May 2010

Klebsiella pneumoniae was found to effect the reductive dechlorination of methoxychlor (2,2-bis(p-mefhoxyphenyl)-1,1,1-trichloroethane) and its dihydroxy derivative (2,2-bis(p-hydroxyphenyl)-1,1,1-trichloroethane) to dichloro derivatives 2,2-bis(p-methoxyphenyl)-1,1-dichloroethane and 2,2-bis(p-hydroxyphenyl)-1,1-dichloroethane, respectively. Dehydrohalogenation to the corresponding diaryl dichloroethylenes, which themselves were not further degraded by this bacterium, was not observed. Cleavage of the methoxy groups to form the hydroxy compounds did not take place.
Interaction of Xanthomonas campestris pv. undulosa or Pseudomonas cepacia with Septoria nodorum in vitro and in vivo
Authors: Jones J. B. , Roane C. W.
Published: May 2010

Xanthomonas campestris pv. undulosa did not inhibit growth or spore germination of Septoria nodorum on wheat leaf extract agar, whereas Pseudomonas cepacia produced a zone of complete inhibition of spore germination up to 17.5 mm and reduced germination up to 5 cm from the bacterial front. Culture filtrates of the two bacteria grown in 'Blueboy' or 'Arthur' wheat leaf extract broth were incorporated into fresh wheat leaf extract broth. These filtrates caused a reduction in growth (dry weight) of S. nodorum compared with growth in unamended extract. Fungal mass was considerably lower in P. cepacia filtrate of 'Arthur' wheat than in the X. campestris pv. undulosa filtrate or the control. The extent of reduction by P. cepacia filtrate suggests an antibiotic effect. In phosphate buffer, X. campestris pv. undulosa reduced spore germination and germ tube length of S. nodorum, while P. cepacia inhibited germination and germ tube growth completely. In vivo, X. campestris pv. undulosa had no effect on spore germination but did reduce germ tube length whereas P. cepacia inhibited both parameters.
Effect of glucose concentration in the growth medium on the synthesis of fatty acids by the yeast Candida bogoriensis
Authors: Cutler Adrian J. , Light Robley J.
Published: May 2010

The yeast Candida bogoriensis produced large quantities of an extracellular glycolipid, the diacetyl sophoroside of 13-hydroxydocosanoic acid, when grown on a standard glucose rich medium (3% glucose, 0.15% yeast extract), but not when grown on a low glucose medium (0.5% glucose, 0.4% yeast extract) (A. J. Cutler and R. J. Light. 1979. J. Biol. Chem. 254: 1944–1950). Glucose levels also affected the quantity and distribution of the free fatty acid and triglyceride fractions synthesized by this organism. Cells grown on the low glucose medium contained palmitate and stearate as the major fatty acids in these two fractions, and a 3-h incubation with [1-14C]acetate led primarily to the labeling of these two acids. Cells grown on the standard enriched glucose medium contained relatively less stearate and more behenate than the low glucose grown cells, and the incorporation of [1-14C]acetate into stearate was decreased, while that into behenate was increased.Supplementation of low glucose grown cells with glucose led to a rapid stimulation of fatty acid synthesis, primarily palmitate and stearate in the free fatty acid fraction and stearate in the triglyceride fraction. Total triglyceride began to increase a few hours after supplementation, but synthesis of the extracellular glycolipid, and hence 13-hydroxydocosanoic acid, did not occur until 12–24 h after supplementation. The stimulation by glucose of long chain fatty acid synthesis in C. bogoriensis was therefore a process distinct from the glucose stimulation of palmitate and stearate synthesis, though the two events may be causally related.
Antiviral activity of antibiotic-producing marine bacteria
Authors: Toranzo Alicia E. , Barja Juan L. , Hetrick Frank M.
Published: May 2010

The stability of poliovirus 1 in estuarine water and sediment was examined. The present data indicated that a 2 log reduction in virus titer at 15 °C occurred within 6–7 days in water samples taken from estuarine waters on both sides of the Atlantic Ocean. The antiviral effect decreased significantly when the seawater was subjected to autoclaving but not when it was filtered. That the antiviral activity of the seawater was related to the growth activities of microorganisms was corroborated by the isolation of antibiotic-producing marine bacteria that had marked activity against poliovirus (net inactivation ≥ 2 logs within 6–8 days). These organisms retained this activity following repeated subcultivation on laboratory media. Since comparable inactivation rates were observed in cell-free filtrates from these marine strains, extracellular products appear to be involved in the virus-inactivation process. Other enteric viruses, Coxsackie B-5 and ECHO-6, were also inactivated by these marine bacteria. The addition of sediment to natural seawater increased the length of poliovirus survival more than three times over that in seawater alone. However, this was not found under sterile conditions, suggesting that the sediment can protect the viruses from inactivation by the marine microflora.
Nalidixic acid inhibits the conjugal transfer of conjugative N incompatibility group plasmids
Authors: Gill S. , Iyer V. N.
Published: May 2010

The conjugal transfer of R plasmids of the N incompatibility group was inhibited by nalidixic acid to the same degree as that of plasmids of other conjugative and incompatibility groups. Inhibition was reversible. This supports a belief that nalidixic exerts its effect by interfering with a step(s) that is common to all conjugative systems among Enterobacteriaceae. These observations do not support an earlier suggestion that motivated the present study, and a reason for this is suggested.
Bacteriocin production by Streptococcus milleri
Authors: Drucker D. B. , McKillop C. M.
Published: May 2010

Bacteriocinlike activity was sought among 58 streptococcal strains using a deferred antagonism technique and 50 indicator strains. Antagonist production was generally increased by glucose supplementation of brain heart infusion agar and reduced by addition of calcium carbonate. Activity due to complete bacteriophage was excluded, as was toxic buildup of lactate, acetate, or ethanol. Hydrogen peroxide activity was responsible for all, or part, of antagonist activity in Streptococcus mitior and in three strains of Streptococcus milleri. Bacteriocinlike activity was confirmed in the strain of Streptococcus mutans tested and in nine strains of S. milleri. Virtually all isolates of S. milleri tested were sensitive to the bacteriocinlike activity of S. mutans NCTC 10832.
Effects of wash treatments on the ultrastructure and lysozyme penetrability of the outer membrane of various marine and two terrestrial gram-negative bacteria
Authors: Laddaga Richard A. , MacLeod Robert A.
Published: May 2010

Twenty-three marine and two terrestrial gram-negative bacteria were examined for the effect on the outer membrane of the cells of washing the organisms successively in 0.5 M NaCl and 0.5 M sucrose, a procedure which brings about the loss of the outer membrane from Alteromonas haloplanktis 214. Six organisms lost their outer membrane completely, three lost it partially, and six retained it but in a form which indicated that the membrane had been affected extensively. The remaining 10 organisms including the two terrestrial species, Escherichia coli and Pseudomonas aeruginosa, showed no changes detectable in thin section by electron microscopy. None of the 16 organisms which retained their outer membrane after washing were converted from rod forms to spheres by lysozyme before washing but 12, including Pseudomonas aeruginosa, formed spheres in the presence of the enzyme after the wash treatment. For many of the latter organisms, treatment with lysozyme caused large segments of the outer membrane of the cells to be removed. Losses in cell viability following washing and treatment with lysozyme paralleled the extent of damage to the outer membrane perceived by electron microscopy.
Fermentation of D-xylose, xylitol, and D-xylulose by yeasts
Authors: Maleszka Ryszard , Schneider Henry
Published: May 2010

Fifteen yeasts which can assimilate D-xylose were examined for the ability to convert this pentose to ethanol. In six of the seven genera investigated the conversion was enhanced when air had access to the medium. Therefore, the ability to convert D-xylose to ethanol under these conditions is probably common among yeasts. Growth under the same conditions on xylitol, a putative catabolite of D-xylose, led to only traces of ethanol. The effects of growth on another putative catabolite, D-xylulose, were complex, but some of the strains which were among the better producers of ethanol from D-xylose produced less from D-xylulose.
Electron microscopic study of Bluegill virus
Authors: Berthiaume Laurent , Robin Jean , Alain Robert
Published: May 2010

Bluegill virus (BGV) grown in BF-2 cells was studied by negative staining and ultrathin sections of infected cells. Although BGV resembles bunyaviruses in gross physical appearance, it differs from this group in several important aspects. Thus, BGV cannot be classified as a member of the Bunyaviridae family and could be a representative of a novel family of enveloped RNA viruses.
Bacillus thuringiensis in grain elevator dusts
Authors: DeLucca II Anthony J. , Palmgren Muriel S. , Ciegler Alex
Published: May 2010

Grain dust from four large grain elevators along the Mississippi River near New Orleans, Louisiana, were analyzed for the presence of Bacillus thuringiensis, a pathogen of lepidopterous insects. Both settled grain dust and respirable grain dust samples were taken. A total of 20 settled and 53 respirable dust samples were assayed. No insects, alive or dead, insect parts, webbing, or feces were observed. Of the settled dust samples, 55.0% contained Bacillus thuringiensis, while 16.9% of the respirable dust samples were positive for this organism. Two hundred and fifty-five Bacillus colonies were studied, with 30.9% being Bacillus thuringiensis. Serological and biochemical tests showed 94.9% of them to be variety aizawai. Other varieties present were morrisoni, canadensis, indiana, and kurstaki.
Photochemical interaction of dictamnine, a furoquinoline alkaloid, with fungal DNA in vitro and in vivo
Authors: Pfyffer Gaby E. , Towers G. H. Neil
Published: May 2010

The furoquinoline alkaloid dictamnine has been shown to provoke lethal damage to filamentous fungi in near ultraviolet light. The phototoxicity was more pronounced against Mucor hiemalis and Mucor ramannianus than against Fusarium graminearum and Penicillium italicum. In vitro, labeled dictamnine was shown to form covalent monoadducts with purified DNA from M. hiemalis in the presence of long-wave ultraviolet light. Addition of [3H]dictamnine to cultures of the same organism showed photobinding with the fungal DNA in vivo. These results support the suggestion made earlier, on the basis of in vitro experiments with calf thymus DNA, that DNA represents a major cellular target in vivo for the phototoxicity of the alkaloid.
Glucose suppression of β-glucosidase activity in a chloramphenicol-producing strain of Streptomyces venezuelae
Authors: Chatterjee S. , Vining L. C.
Published: May 2010

β-Glucosidase activity was induced in Streptomyces venezuelae during growth on cellobiose, gentiobiose, salicin, methyl β-glucoside, and p-nitrophenyl β-D-glucopyranoside. Activity in cell extracts was separated by DEAE-cellulose chromatography into two fractions differing in substrate preference. One component showed higher activity with, and was more strongly induced by, cellobiose; the other showed greater activity and inducibility with salicin. Addition of glucose to cultures severely depressed induction of β-glucosidase activity by cellobiose but not by salicin. Acetate and several amino acids inhibited induction by either substrate. The action of glucose was not reversed by cyclic AMP. Cultures of S. venezuelae using glucose, cellobiose, or a mixture of the two saccharides as their carbon source produced chloramphenicol during growth. In contrast with its effect on the induction of cellobiase activity, glucose did not suppress chloramphenicol production, indicating that the control mechanisms that establish carbon source preferences are not linked to those that regulate antibiotic biosynthesis in this organism.
Production of lipids and lipase activity during growth of Mucor hiemalis
Authors: Mirza A. Qayum , Akhtar M. Waheed , Nawazish M. Nadeem , Chughtai M. I. D.
Published: May 2010

Production of lipids and lipase activity by a strain of Mucor hiemalis known to have potential for high lipase activity was studied in a medium containing glucose as the carbon source. Most of the glucose was utilized by the end of the growth phase when the mycelium showed maximal lipase activity (17 U/g dry mycelium) as well as maximal lipid content (13 mg/g dr*** mycelium). Maximal broth lipase activity (76 U/100mL) was observed after cell lysis had begun. The fractions identified in the mycelial lipid extracts were sterol esters, triglycerides, fatty acids, diglycerides, sterols, monoglycerides, phosphatidylethanoamine, phosphatidylcholine, phosphatidylserine, and an unknown polar lipid. The proportion between the neutral and the polar lipids was only 0.06 at 44 h, increasing gradually to 1.51 at 164 h of fermentation. A relationship between the production of lipase and the neutral lipids appears to exist.
Lipid catabolism of cultivated treponemes
Authors: Trevathan Carol Ann , Smibert Robert M. , George Hugh A.
Published: May 2010

Treponema require long-chain fatty acids for growth in vitro. Serum, added to culture media, provides a source of long-chain fatty acids. These fatty acids, however, are esterified to triglycerides, phospholipids, and cholesterol. In this study, the major pathways of complex lipid catabolism in T. phagedenis, T. denticola, T. refringens, T. minutum, and T. vincentii were investigated. Lipase activity was demonstrated in five Treponema species using four lipid substrates. Chromatographic data demonstrated that, during growth, treponemes completely utilized lysophosphatidylcholine, present in serum-supplemented culture media, while phosphatidylcholine and phosphatidylinositol were not utilized. Phospholipase B and glycerophosphoryl-choline diesterase activities were demonstrated in the five species of Treponema studied. Treponema phagedenis and T. denticola had phosphatase activity, while T. refringens, T. minutum, and T. vincentii did not have an acid phosphatase activity. Phospholipase A, C, and D and alkaline phosphatase activities were not found in five species of Treponema. Based on the enzymes demonstrated in this study, two pathways of phospholipid catabolism are proposed.
Nicotinamide adenine dinucleotide and nicotinamide adenine dinucleotide phosphate splitting enzyme(s) of sheep and rabbit erythrocytes: their effect on the growth of Haemophilus
Authors: Artman M. , Frankl G.
Published: May 2010

Fragility of rabbit erythrocytes in agar plates results in gradual release of their NAD and NADP contents into the medium. Due to high NADase and negligible NADPase activity of rabbit red blood cell stroma at neutral pH, the NAD released into the medium is hydrolyzed and NADP remains intact. Thus, rabbit erythrocytes and their lysates support the growth of NAD(P)-requiring Haemophilus by serving as a source of NADP.Stability of sheep erythrocytes in agar plates results in retention of their NAD and NADP contents and consequently in inhibition of growth of NAD(P)-requiring Haemophilus. The highly active NAD- and NADP-splitting enzyme(s) of sheep red blood cell stroma prevent(s) the growth of Haemophilus on sheep blood lysates through inactivation of both NAD and NADP which are released into the medium.
Cross protection in mice with the Smith diffuse strain of Staphylococcus aureus versus a type Ia strain of group B streptococci
Authors: Ichiman Yoshitoshi , Yoshida Kosaku
Published: May 2010

Active immunization of mice with whole cell vaccine or cell surface polysaccharide from either the Smith diffuse strain of Staphylococcus aureus or SS-615 (type Ia of group B streptococci) protected against challenge by either the homologous or heterologous strains. In the peritoneal cavity of mice immunized with either of these organisms rapid phagocytosis and reduction of the viable cells was observed at 6 h after the challenge. Cell surface polysaccharides extracted from strains Smith diffuse and SS-615, both prepared by the same procedure as that of the Smith surface antigen, were capable of absorbing the protective antibody in rabbit hyperimmune sera prepared with homologous or heterologous strains.
Structural features of the vesicle of Frankia sp. CpI1 in culture
Authors: Torrey John G. , Callaham Dale
Published: May 2010

The filamentous bacterium Frankia sp. CpI1 of the Actinomycetales, responsible for symbiotic nitrogen fixation in the nodules of certain woody dicots, also fixes dinitrogen when grown independently of the host in a nitrogen-free synthetic nutrient medium under aerobic conditions. In structural studies of Frankia grown in culture it has been shown that the bacterial filaments form vesicles, enlarged terminal endings in which the enzyme nitrogenase is formed. Microscopic examination of cultures shows that the vesicles possess a specialized envelope consisting of a number of thin layers or laminae which in polarized light show birefringence and in freeze-etch electron microscopy are resolved as multiple (12–15) laminae approximately 35–40 Å (1 Å = 0.1 nm) in thickness. Comparisons are made between the structure of the vesicle envelope in cultured Frankia and the strikingly similar innermost laminated layer in the dinitrogen-fixing heterocysts of the cyanobacterium Anabaena. Comparable protective functions in limiting oxygen to the dinitrogen-fixing sites are suggested for these similar structures in two quite unrelated microorganisms.
Associative symbiosis of Azospirillum lipoferum with dicotyledonous succulent plants of the Indian desert
Authors: Rao A. V. , Venkateswarlu B.
Published: May 2010

The roots of several dicotyledonous xerophytic plants exhibited nitrogenase activity. Azospirillum lipoferum was isolated from the roots of these plants including several species of Opuntia having crassulacean acid metabolism. These isolates showed high rates of acetylene reduction; maximum nitrogenase activity was observed with the isolate from Opuntia vulgaris. Organic acids rather than sugars were preferred as carbon source for two selected isolates studied. However, no activity was detected with formic, oxalic, or lactic acid. Inorganic nitrogen sources caused significant reduction in nitrogenase activity, while organic sources such as amino acids and proteins either stimulated or did not significantly inhibit the activity. However, urea completely inhibited formation of nitrogenase activity. Growth measured as optical density was enhanced with all the nitrogen sources except potassium nitrite.
Effect of carbohydrates on the antibacterial activity of patulin on Streptococcus bovis
Authors: Escoula L.
Published: May 2010

The antibiotic activity of patulin on Streptococcus bovis varied in the presence of different sugars in the incubation medium. The 50% inhibitory concentration (IC50) of patulin was 4.5 times greater in the medium containing glucose than in the lactose-containing medium (100.5 versus 22 μg/mL). The addition of two sugars (glucose plus lactose) to the medium was followed by the utilization of glucose only when patulin was present; lack of growth on lactose was not due to β-galactosidase inactivation by patulin.
A cyclohexanecarboxylic acid utilizing yeast: isolation, identification, and nutritional characteristics
Authors: Hasegawa Yoshie , Higuchi Kiyoyuki , Obata Hitoshi , Tokuyama Tai , Kaneda Toshi
Published: May 2010

A yeast capable of utilizing cyclohexanecarboxylic acid as sole carbon and energy source, strain KUY-6A, was isolated from soil by enrichment cultures. Taxonomical studies indicated that strain KUY-6A was Trichosporon cutaneum. Strain KUY-6A grew on a number of carboxylic acids. Among the cyclic compounds tested, cyclohexanecarboxylic acid was the best substrate. Cyclopentanecarboxylic acid, cycloheptanecarboxylic acid, cyclopentanone, cyclohexanone, and cyclopentanol also supported growth. In addition, the organism used the monocarboxylic acids, butyric, valeric, and caproic; the dicarboxylic acids, succinic, glutaric, adipic, pimelic, and suberic; and the aromatic acids, benzoic and o-, m-, and p-hydroxybenzoic. The yeast did not require any vitamins for growth, although thiamine gave slight stimulation. The cell dry weight yield was 0.75 g from 1 g of cyclohexanecarboxylic acid used.
Control of pH in liquid cultures of microorganisms with an ion-exchange resin
Authors: Styer D. J. , Durbin R. D.
Published: May 2010

A simple, cation-exchange resin-buffering system is described which can maintain the pH of microbial cultures within 1 pH unit of the initial value. This system buffers over the pH range of 3.5–9 and works in both defined and complex media.
Dehydroxylation of glycocholic acid by Curvularia coicis
Authors: Johns M. R. , Chong R. , Maddox I. S.
Published: May 2010

Curvularia coicis transforms glycocholic acid, but not cholic acid, in whole cell cultures to deoxycholic acid in 3% yield. Cell-free extracts can act on both substrates to yield deoxycholic acid. Still cultures, as well as cell-free extracts, of C. coicis dehydroxylate glycocholic acid (7α hydroxyl group) to glycodeoxycholic acid.
Light and electron microscopy of conjugation in the yeast, Schizosaccharomyces octosporus
Authors: Ashton M.-L. , Moens P. B.
Published: May 2010

Conjugation in Schizosaccharomyces octosporus is described through the use of interference contrast microscopy, fluorescence microscopy, and electron microscopy of serial sections. At the light microscope level, mating was frequently observed to occur between cells of common ancestry. Fluorescent staining of the nuclei showed that nuclear migration occurs prior to karyogamy, and following diploidization the nucleus then migrates to the end of the cell. A brightly fluorescent spot was found at the apex of the migration nucleus. At the electron microscope level, the results showed that nuclear movement occurs in the presence of cytoplasmic microtubules that are associated with the spindle pole body, the conjugatory nuclei first fuse at or near the spindle pole bodies, and fusion of the spindle bodies occurs apparently by stacking one onto the other.
Evaluation of Frankia strains isolated from provenances of two Alnus species
Authors: Normand P. , Lalonde M.
Published: May 2010

Using the OsO4 isolation method, more than 200 Frankia strains were obtained from 27 provenances of the two alder species represented in Quebec, i.e., Alnus crispa (Ait.) Pursh. and Alnus rugosa (Du Roi) Spreng. The Frankia isolates were evaluated for morphological characteristics, infectivity, and efficiency. Variations in these factors were noted between provenances and also between isolates from a single provenance. The distribution of sporulating (Sp+) and nonsporulating (Sp−) type isolates was found to be related to host plants and provenance. The sporulating or nonsporulating endophytic character was found to significantly affect efficiency. This endophytic character was recognized as one of the valid criteria that should be used in the awaited species definition in the genus Frankia.
Location and kinetic properties of the cellulase system of Acetivibrio cellulolyticus
Authors: MacKenzie C. R. , Bilous D.
Published: May 2010

The cellulose-solubilizing and carboxymethylcellulase activities of Acetivibrio cellulolyticus were observed to exist largely in a soluble form whereas β-glucosidase activity was cell associated. Reducing agents significantly enhanced cellulose-solubilizing activity, and thiol-binding agents at micromolar concentrations resulted in almost total inhibition of this activity. Carboxymethylcellulase activity was also inhibited by these agents but to a lesser degree. Cellulose-solubilizing activity was strongly stimulated by Mg2+ and Ca2+ but these ions had a negligible effect on carboxymethylcellulase activity. Cellulase activity was not inhibited by glucose and only slightly by cellobiose. A strong preference for p-nitrophenylglucoside over cellobiose by β-glucosidase activity was observed.
Effects of nutrient enrichment on the colonization and decomposition of plant detritus by the microbiota of an arctic lake
Authors: Federle Thomas W. , McKinley Vicky L. , Vestal J. Robie
Published: May 2010

The effects of nitrogen and phosphorus enrichment on the colonization and decomposition of plant litter (Carex) by the microbiota of Toolik Lake, Alaska, were studied in microcosms. Added phosphorus resulted in a fourfold (p ≤ 0.01) increase in the levels of ATP associated with the microbiota on fresh litter, while nitrogen-plus-phosphorus enrichments resulted in a twofold increase in the ATP associated with the microbiota of fresh (p ≤ 0.01) or partially degraded (p ≤ 0.05) litter compared with controls. Neither nitrogen nor phosphorus enrichments, alone or together, significantly altered the observed weight loss of either fresh or partially degraded litter, although additional phosphorus was immobilized by the litter microbiota when available. Subsequent experiments demonstrated that the increase in ATP resulting from nutrient enrichment occurred when the microcosms were incubated in daylight but not in the dark, suggesting that nutrient enrichment primarily stimulated the photosynthetic component of the detrital community.
Immunogenicity of potassium thiocyanate extracted and electrofocused Pasteurella multocida X-73I antigens in chickens and mice
Authors: McKinney Kevin L. , Rebers Paul A. , Rimler Richard B.
Published: May 2010

The immunogenicity of antigenic fractions obtained by the extraction of Pasteurella multocida strain X-73 (serotype 1) with potassium thiocyanate (KSCN) was determined in chickens and mice. The initial KSCN extract was centrifuged at 105 000 × g, and the antigens were separated into a particulate fraction (40p) and a soluble supernatant fraction (40s). The ultracentrifuged fractions were further resolved by preparative electrofocusing. The 40p fraction was resolved into two subgroups having isoelectric points of 3.5–3.9 and 5.5–6.0; the 40s fraction was resolved into five subgroups ranging in isoelectric points from 4.4 to 9.0. The 40p fractions were antigenically similar and contained lipopolysaccharide (LPS) and protein. The 40s fractions were antigenically distinct from the 40p fractions and from each other; they contained proteins and polysaccharides but no LPS. The 40p antigens were strongly immunogenic in mice and chickens, whereas the 40s antigens were weakly immunogenic in chickens and not immunogenic in mice. The incorporation of Freund's complete adjuvant increased the immunogenicity of the 40s antigens in chickens. The 40p antigens induced greater frequencies of serological responses in chickens than the 40s antigens as detected by counterimmunoelectrophoresis and immunodiffusion. This suggested that the increased protection associated with the 40p antigens may have been the result of better antibody response. The toxicity of all the fractions was evaluated by determination of lethality for 10-day-old chicken embryos because of the sensitivity and reliability of the test. The 40p fraction had an LD50 = 0.38 μg, and the 40s fraction had an LD50 = 2.5 μg. Since the 40s fraction contained no detectable LPS, it is likely that two toxins are present, one which contains LPS and one which does not.
Phytoplankton in marine surface microlayers
Authors: Carlson David J.
Published: May 2010

Surface microlayer phytoplankton populations were monitored to assess natural temporal and spatial variability. Microlayer samples (collected using glass plates) were compared with reference bulkwater samples over hourly, diel, and seasonal time periods on spatial scales of ~0.5 to 20 km. Microlayers were consistently depleted in chlorophyll a relative to bulkwaters in diurnal samples. Depletions had no seasonal patterns and were not influenced by dissolved nutrients or organic materials or by varying wave states. A diel pattern, with nocturnal enrichments, indicated photoinhibition of microlayer microbiota. Exceptions to these patterns occurred in naturally slicked surfaces which generally had large chlorophyll a enrichments. Disparate descriptions of microlayer phytoplankton populations in previous work probably resulted from (1) use of different sampling methods, (2) geographic variations in bulkwater phytoplankton biomass, (3) low numbers of samples, and (4) uncertain identification or definition of slick conditions.
Ovine ill-thrift in Nova Scotia. 9. Production of experimental quantities of isocyanide metabolites of Trichoderma hamatum
Authors: Brewer D. , Feicht A. , Taylor A. , Keeping J. W. , Taha A. A. , Thaller V.
Published: May 2010

Laboratory cultures of Trichoderma hamatum produce metabolites that are characterized by an isocyanide functionality. Three such metabolites predominate. One is the known compound trichoviridin (I). The other two, described here for the first time, are 3-(3-isocyano-6-oxabicyclo[3,1,0]hex-2-en-5-yl)acrylic acid (II) and a very unstable compound 3-(3-isocyanocyclopent-2-enylidene-)propionic acid (III). Production of these three metabolites by a random sample of wild isolates of the fungus has been examined. At least one of these isocyanides was isolated from all cultures in which the culture broth inhibited the growth of Micrococcus luteus. The relative amounts of the three isocyanides produced by individual isolates were not the same and cultures were found in which I, II, or III was the main product. The isocyanide III was produced by all wild isolates which had antibiotic activity in their culture broth, and it was present in the concentration range 2–40 mg∙L−1.
Burst size of bacteriophage SP82 as a function of growth rate of its host Bacillus subtilis
Authors: Webb Vera , Leduc Eugene , Spiegelman George B.
Published: May 2010

The burst size of bacteriophage SP82 in Bacillus subtilis has been measured under conditions of varying bacterial growth rates. The natural logarithm of the burst size was found to vary linearly with cell growth rate.
The metabolism of cyclohexanecarboxylic acid and 3-cyclohexenecarboxylic acid by Pseudomonas putida
Authors: Blakley E. R. , Papish B.
Published: May 2010

A strain of Pseudomonas putida grew rapidly on cyclohexanecarboxylic acid as a sole source of carbon. A CoA-mediated β-oxidation pathway was induced for the metabolism of the compound. The organism could not utilize 3-cyclohexenecarboxylic acid as a sole source of carbon for growth, but cells grown on gluconate in the presence of 3-cyclohexenecarboxylic acid were induced to metabolize cyclohexanecarboxylic acid, benzoic acid, and catechol. Evidence is presented that 3-cyclohexenecarboxylic acid was slowly metabolized by a β-oxidation pathway and by a pathway involving benzoic acid as an intermediate. For this strain of Pseudomonas putida, 3-cyclohexenecarboxylic acid acts as an oxidizable, nongrowth substrate and induces the metabolism of cyclohexanecarboxylic acid and benzoic acid.
Studies on the ontogeny and ultrastructure of the sclerotium of Botrytis cinerea Pers. ex Nocca & Balbis
Authors: Willetts H. J. , Bullock Suzanne
Published: May 2010

The ontogeny and ultrastructure of sclerotia of the fungus Botrytis cinerea Pers. ex Nocca & Balbis were studied by light, scanning, and transmission electron microscopy. Exudation droplets of various sizes and colour accumulated on sclerotial surfaces during development and eventually disappeared. A surface hyphal weft was present over sclerotia at maturity, forming a dense covering which often obscured the underlying rind. The rind consisted of highly vacuolated cells with thick, pigmented walls that remained intact even in old sclerotia. The cortex was poorly defined and usually consisted of only one layer of cells. The prosenchymatous medulla constituted the main volume of mature sclerotia. The ultrastructure of young sclerotial hyphae was similar to that of actively growing vegetative hyphae. Hyphae of mature sclerotia contained fewer nuclei and profiles of mitochondria and endoplasmic reticulum than young sclerotial hyphae. Electron-dense structures, tentatively identified as protein and polyphosphate bodies, were observed in hyphae of the cortex and medulla. Sclerotia of B. cinerea were structurally similar to those of Sclerotinia spp.
The regulation of sclerotium initiation in Sclerotium rolfsii by glucose and cyclic AMP
Authors: Hadar Y. , Pines M. , Chet I. , Henis Y.
Published: May 2010

Sclerotium rolfsii, grown in a shaken submerged culture, developed a potential for the formation of sclerotia. This potential was inhibited by the presence of glucose in the culture medium. The cultures were capable of producing sclerotia, after transfer to stationary incubation, when glucose was exhausted and the biomass reached its maximal level. The level of adenosine 3′,5′-cyclic monophosphate (cAMP) sharply increased upon glucose depletion and decreased upon glucose addition. Sclerotium rolfsii was grown in a chemostat with glucose of limiting concentration at a dilution rate of 0.05/h. Samples from the chemostat possessed the potential to produce initials when poured into empty Petri plates. Addition of glucose to these plates changed the fungal growth pattern from further differentiation to vegetative growth. Glucose supplementation to clearly differentiated initials did not inhibit further development. It was observed that during morphogenetic events endogenous substrates, e.g., cell wall components, were utilized.
Ultrastructural studies of Gaeumannomyces graminis in the waterfilms on wheat roots and the effect of clay on the interaction between this fungus and antagonistic bacteria
Authors: Campbell R.
Published: May 2010

The hyphae of Gaeumannomyces graminis and the cells of some antagonistic bacteria adsorb clays and this may affect the ability of the antagonists to lyse the hyphae. The use of frozen hydrated specimens for scanning electron microscopy shows that some sand, plant root, and microbial surfaces are not covered with mucilage and water films. Hyphae especially may pass through liquid–gas interfaces very frequently and their surfaces may pass from being a solid–liquid interface to a solid–gas interface over very short distances. The effect of these changing interfaces on adsorption of clay and bacteria is discussed.
Inactivation of nuclease H of the moderate halophile Micrococcus varians ssp. halophilus during cultivation in the presence of salting-in-type salts
Authors: Kamekura Masahiro , Onishi Hiroshi
Published: May 2010

Effects of anions and cations on the nuclease H production of the moderate halophile Micrococcus varians ssp. halophilus were observed in complex media containing various neutral salts at 30 °C. Nuclease H activity was detected in cultures containing NaCl, KCl, RbCl, CsCl, and Na2SO4, but almost none was detected in cultures containing LiCl, NaBr, NaI, or NaNO3. When the halophile was cultivated in medium containing NaBr or NaNO3 at lower temperatures (20–25 °C), nuclease H activity could be detected in supernatants. The order of stabilizing effect for nuclease H at 30 °C was shown to be CH3COO−, SO42− > Cl− > NO3− > Br− > I− > ClO4− > SCN− for anions and Na+ > K+ > Rb+ > Cs+ > Li+ for cations.
Production by Bacillis subtilis of brown sporulation-associated pigments
Authors: Barnett Terry A. , Valenzuela David , Riner Steven , Hageman James H.
Published: May 2010

The mode of production of the brown pigments of Bacillus subtilis 168 L-4, pigments frequently used as phenotypic markers for sporulation in this organism, has been studied. A defined liquid medium which promoted maximal pigment formation was developed. Five brown components, which could be resolved by thin-layer chromatography, were produced in the culture broth. Removal of cells from the medium at the end of logarithmic growth did not alter the type or amount of the pigments formed, indicating that the cells excreted pigment precursors into the medium during growth. Pigment formation from the precursors was found to occur by an oxygen-requiring, base-dependent, Mn2+- requiring, nonenzymatic pathway. Pigment production was also stimulated by the presence of tyrosine and histidine in the medium. The increases in extracellular pH often associated with spore formation in B. subtilis might be the cause of the concomitant appearance of brown pigments.
Adaptation of Agaricus campestris (NRRL 2334) to a peat extract medium
Authors: Martin Antonio M.
Published: May 2010

The utilization of peat extracts as a substrate source in the submerged growth of fungal mycelium has been investigated. Successive shake flask fermentations were carried out to adapt Agaricus campestris NRRL 2334 to growth on acid extracts of milled sphagnum peat as the only nutrient source. The cultivations were conducted in 250-mL flasks with 100 mL of medium incubated for 6 days at 24 °C and 150 rpm at three different values of initial pH, 5.0, 6.0, and 7.0, and at two different values of inoculum ratio, 5 and 10% (v/v). A progressive increase in the concentration of peat extract in the culture medium, expressed by increasing values of the total carbohydrate concentration of the peat extract in successive steps, resulted in a better adaptation than that obtained after successive transfers in nondiluted peat extract. An initial step of cultivation in a glucose–yeast extract medium was required for better adaptation. The results, reported as dry biomass produced to total carbohydrate consumed and to initial total carbohydrate, suggest that growth-inhibitory substances are present in the peat extract and also are produced during the fermentation.
Physiology of sea ice diatoms. II. Dark survival of three polar diatoms
Authors: Palmisano Anna C. , Sullivan Cornelius W.
Published: May 2010

Three polar sea ice diatoms were exposed to 5 months of darkness at −2 °C to simulate polar winter conditions. Cells were tested monthly for the ability to initiate growth of a population. A critical percentage (~1–100%) of a nonaxenic population of each diatom remained viable after 5 months of dark incubation. Survival was generally enhanced by preconditioning cells with a simulated summer–winter transition (decreasing light and temperature, increasing salinity) or a simple light–dark transition; however, preconditioning was not essential to the survival of sea ice diatom cultures under winter conditions.
Isolation of round-cell mutants of Salmonella typhimurium
Authors: Antón Dora N. , Micheli Ana T. de , Palermo Ana M.
Published: May 2010

Round-cell mutants of Salmonella typhimurium affected in genes divD, envB, and rodA (or pbpA) were obtained, without specific selection, in strains hypersensitive to overproduction of the histidine enzymes. All those types of round-cell mutations promoted cell division, suppressing the filaments formed by histidine-derepressed strains in media containing 2% dextrose. Only envB and rodA or pbpA mutants were found in round-cell strains isolated by resistance to mecillinam. divD mutants did not appear because, in spite of their definite round-cell morphology, they remain sensitive to mecillinam.
The effect of hydroxyurea on DNA synthesis of Tipula iridescent virus and Estigmene acrea cells
Authors: Kloc Malgorzata , Lee Peter E.
Published: May 2010

Viral-specific DNA synthesis of Tipula iridescent virus (TIV) was not affected in Estigmene acrea cells which were continuously exposed to 300 μg/mL hydroxyurea (HU) as detected by light microscope autoradiography. Electron microscopy of such cells showed viroplasmic centres with virions in various stages of development. In nor mal cells similarly exposed to HU, nuclear DNA synthesis was reduced by 70–80%.
Growth requirements of Clostridium saccharolyticum, an ethanologenic anaerobe
Authors: Murray William D. , Khan A. W.
Published: May 2010

Clostridium saccharolyticum, an obligate anaerobe, which can convert cellulose hydrolysis products to ethanol, acetic acid, H2, and CO2, grew well in a synthetic salt–vitamin medium when supplemented with 1% yeast extract. It also required iron and a reduced form of sulfur, such as cysteine or Na2S (1–10 mM). Good growth occurred in cellobiose, glucose, and xylose syrups of 20, 15, and 10% (w/v), respectively. Clostridium saccharolyticum was not affected by the accumulation of high headspace pressures of H2 or CO2, and grew well in the presence of 0.1 M acetate and 0.5 M ethanol, while 0.24 M acetate and 1.0 M ethanol inhibited growth. The results indicated that C. saccharolyticum has biotechnological potential for the conversion of cellulose and hemicellulose hydrolysis products to ethanol.
Use of rabbit mesentery in the evaluation of adherence of prototrophic and auxotrophic gonococcal strains
Authors: Mathieu L. G. , DeRepentigny J. , Turgeon P. L. , Gadbois T.
Published: May 2010

Gonococcal strains of different nutritional types did not adhere to the same extent to rabbit mesentery in vitro. Prototrophic strains generally showed much more affinity than strains requiring arginine (or ornithine), hypoxanthine, and uracil (AHU− or OHU−) for growth. Rabbit mesentery may be useful in the comparative study of the adherence properties of prototrophic and AHU− or OHU− auxotrophic strains.