bluuebunny/crossref_metadata_2025 huggingface dataset:
Manganese and antibiotic biosynthesis. I. A specific manganese requirement for patulin production in Penicillium urticae
Authors: Scott R. E. , Jones A. , Lam K. S. , Gaucher G. M.
Published: May 2010

The effect of trace metal nutrition on the functioning of the patulin biosynthetic pathway in submerged cultures of Penicillium urticae (NRRL 2159A) was examined by both chromatographic and enzymological means. Comprehensive metal ion analysis showed generally low levels of contaminating metal ions in media components. Of eight metal ions examined, only manganese strongly influenced secondary metabolite production. In control cultures or cultures deficient in calcium, iron, cobalt, copper, zinc, or molybdenum, pathway metabolites appeared in the medium at about 25 h after inoculation. The first pathway-specific metabolite, 6-methylsalicylic acid, accumulated only transiently before being converted to patulin whose concentration steadily increased. In manganese-deficient cultures, however, 6-methylsalicylic acid continued to accumulate, with only minor amounts of patulin being produced. Additionally, a marker enzyme for the pathway showed only 0–20% of control activity. Clear dose responses (patulin versus manganese) were found in different media, with no effect on growth yield. Addition of manganese to depleted cultures at 18, 26, or 36 h resulted in increasing marker enzyme activity and patulin concentrations. It is concluded that manganese exerts a specific, positive effect on patulin biosynthesis and may in some way control the section of the patulin pathway occurring after 6-methylsalicylic acid.
Localization of melanin in appressoria of Colletotrichum lagenarium
Authors: Kubo Y. , Furusawa I.
Published: May 2010

The location of melanin in appressoria of Colletotrichum lagenarium was determined by ultrastructural comparison of the parent strain 104-T, an albino mutant 79215, and an albino mutant 79215 treated with scytalone, a melanin precursor in this fungus. Melanin in appressoria of the parent strain 104-T and that of albino mutant 79215 treated with scytalone was located external to the plasmalemma as a smooth, thin, electron-dense layer. A comparable layer was not observed in appressoria of the albino mutant 79215 without scytalone. Electron microscopic observation of a median section of pigmented appressoria of albino mutant 79215 treated with scytalone indicated that the melanized layer extended over the appressoria with the exception of the pore which provides an opening for the emergence of the infection peg.
Resolution, purification, and characterization of two extracellular glucohydrolases, α-glucosidase and maltase, of Bacillus licheniformis
Authors: Kelly Catherine T. , Giblin Mary , Fogarty William M.
Published: May 2010

Two extracellular α-glucosidases (EC 3.2.1.20, α-D-glucoside glucohydrolase) of Bacillus licheniformis NCIB 8549 were separated, purified, and partially characterized. Resolution of the complex into two separate enzymes was achieved using Sephadex G-150. The first of these activities, a maltase, hydrolysed maltose preferentially. It had slight activity on isomaltose, p-nitrophenyl-α-D-glycopyranoside, and sucrose. The pH optimum was 6.0 and the molecular weight determined on Sephadex G-200 was 160 000. This enzyme did not display any transglucosylation activity. The second enzyme was an α-glucosidase. It displayed highest activity on p-nitrophenyl-α-D-glucopyranoside, followed by isomaltose, sucrose, and maltose. As with the maltase, the pH optimum was 6.0 and the molecular weight as determined on Sephadex G-150 was 66 000. With isomaltose and maltotriose as substrates, transglucosylation activity was evident.
A comparison of carbon source utilization for growth and nitrogenase activity in two Frankia isolates
Authors: Lopez Mary F. , Young Patricia , Torrey John G.
Published: May 2010

The carbon source requirements for the growth and nitrogen fixation of two morphologically distinct Frankia isolates were examined. Isolate ArI3 (from Alnus rubra) grew well on propionate, malate, acetate, and trehalose, and isolate CcI2 (from Casuarina cunninghamiana) grew best on pyruvate, acetate, and propionate. In general, the same carbon sources that supported growth supported both the development of vesicles and nitrogenase activity in long-term induction experiments in both isolates. However, ArI3 cultures induced on proprionate had 7 to 26 times the activity of other carbon sources and ArI3 cultures induced on acetate did not develop any detectable acetylene reduction. In a parallel set of experiments, cultures of both isolates were induced for nitrogenase activity on propionate and the resulting nitrogen fixing cultures were washed free of the organic acid by centrifugation. The washed cultures were incubated in the presence of various carbon sources to determine the ability of a particular substrate to supply energy directly for nitrogen fixation when vesicles and nitrogenase were already present. As was observed in the long-term induction experiments, pyruvate, propionate, and acetate supported the greatest activity in CcI2. Succinate and malate supported the greatest activity in ArI3, and propionate had very little stimulation of acetylene reduction. The reason for the lack of stimulation by propionate for washed cells of ArI3 was unclear but may have been due to toxic concentrations of the organic acid. In an attempt to compare the carbon utilization of ArI3 in pure culture with that in the alder symbiosis, oxygen uptake in the presence of various carbon sources of vesicles clusters isolate from Alnus rubra nodules inoculated with ArI3 was compared with the oxygen uptake of nitrogen-fixing pure cultures of ArI3. The oxygen uptake of the isolated vesicle clusters was stimulated by sucrose, trehalose, and glucose, but not by a variety of organic acids. In comparison, nitrogen-fixing pure cultures of ArI3 readily oxidized sugars and organic acids.
Identification of staphylococci from bovine udders: evaluation of the API 20GP system
Authors: Watts J. L. , Owens W. E. , Nickerson S. C.
Published: May 2010

The API 20GP system (Analytab Products, Plainview, NY) correctly identified 56.1% of staphylococci isolated from the bovine mammary gland. The system identified 90.2% of Staphylococcus aureus strains, but failed to recognize strains of Staphylcoccus hyicus and others. Poor performance was attributed to the limited number of veterinary strains contained in the profile index data base. The API 20GP was determined to be an unacceptable method for identification of staphylococci isolated from the bovine mammary gland.
Immune responses of mice to inactivated rabies vaccine administered orally: potentiation by Quillaja saponin
Authors: Maharaj I. , Froh K. J. , Campbell J. B.
Published: May 2010

Administered orally, Quillaja saponin markedly potentiated the humoral immune responses of mice fed inactivated rabies vaccine, and significantly increased their resistance to subsequent intracerebral challenge with live rabies virus. Although mean serum neutralizing antibody titres were generally 8- to 16-fold higher when vaccine was given intraperitoneally, orally administered vaccine, with saponin, stimulated production of high protective antibody levels that were maintained for at least 6 months. The potentiating effect of saponin appeared to be mediated through several mechanisms, one of which was by increasing the permeability of the intestinal mucosa, allowing increased uptake of viral antigen. The potentiating effect was enhanced when saponin was administered in advance (up to at least 16 h) of the oral vaccine. Mice tolerated the effective saponin doses without any visible signs of distress or injury. In view of the many favourable physiological activities and low toxicity of orally delivered saponins, it is suggested that they may find more general applications in the immunopotentiation of oral vaccines.
Multiplication of Legionella pneumophila Philadelphia-1 in cultured peritoneal macrophages and its correlation to susceptibility of animals
Authors: Yoshida Shin-Ichi , Mizuguchi Yasuo
Published: May 2010

Intracellular growth of Legionella pneumophila Philadelphia-1 strain in peritoneal macrophages (PMP) from various rodents was measured and its correlation to the level of susceptibility of the animal was examined. In guinea pig PMP, the organism grew well and the guinea pig was very susceptible to it (50% lethal dose, LD50 = 7.6 × 104). On the other hand, the bacteria hardly multiplied in mouse PMP and the animal was resistant to infection (LD50 = 6.7 × 107). Intracellular growth rate correlated well with susceptibility in these animals. In golden hamsters, a discrepancy between intracellular growth and susceptibility was found. The organism grew intracellularly as rapid as in guinea pig PMP, but the golden hamster was very resistant to infection (LD50 = 2.2 × 108). In rat PMP, the organism did not grow intracellularly during a 24-h period of infection, but started to grow after that and the growth rate thereafter was as rapid as in guinea pig PMP. WKA rats were resistant and the LD50 in the animal was 1.9 × 107. In vivo natural resistance of rats and golden hamsters to the organism was considered to be a result of other factors than macrophages.
DNA homology studies of rhizobia from Cicer arietinum L.
Authors: Chakrabarti S. K. , Mishra A. K. , Chakrabartty P. K.
Published: May 2010

The taxonomic status of rhizobia which infect Cicer arietinum is poorly defined. Historically these organisms have been placed under Rhizobium leguminosarum; however, later reports suggested that they be treated as a separate cross-inoculation group. Therefore, DNA homology tests were carried out with various rhizobia. The data indicate that rhizobia from Cicer cannot be placed under any of the recognised species of Rhizobium.
Molar growth yield of Nitrobacter agilis in batch culture
Authors: Tsai Yu-Li , Tuovinen Olli H.
Published: May 2010

The molar growth yield (YG) of Nitrobacter agilis was determined with the use of 14CO2 fixation and protein measurement. A low YG of 0.220 g dry weight per mole nitrite oxidized was obtained. Assuming 4 or 6 mol ATP utilized per NAD(P)+ reduced, 10.8 or 14.5% of the theoretical amount of ATP available is utilized for the observed YG.
Characterization of a plasmid in isolates of Corynebacterium sepedonicum
Authors: Clark Mervyn C. , Lawrence C. Harold
Published: May 2010

Lysis of mid-log phase cells of the Gram-positive bacterium, Corynebacterium sepedonicum, by a combination of lysozyme treatment and incubation with alkaline sodium dodecyl sulfate at 56 °C led to the recovery of a single plasmid. The plasmid was purified in CsCl density gradients, and its molecular weight estimated to be 31 megadaltons (46 kilobases), as determined from its relative mobility in agarose gels, from its contour dimensions in electron micrographs, and from the size of the fragments generated when it was cleaved with various restriction endonucleases. Thirteen widely divergent isolates of C. sepedonicum were screened for the presence of plasmid, and of these, 11 were shown to harbour a single plasmid at a level of about 30 copies per cell. Cleavage of the plasmid with PstI gave an identical banding pattern in agarose gels for the fragments from all of the plasmid-carrying isolates. The relevance of plasmid incidence and distribution in C. sepedonicum is discussed in relation to the possibility of developing a test for the detection of bacterial ring rot by using plasmid DNA as a hybridization probe.
Purification and partial characterization of a Vibrio hollisae hemolysin that relates to the thermostable direct hemolysin of Vibrio parahaemolyticus
Authors: Yoh Myonsun , Honda Takeshi , Miwatani Toshio
Published: May 2010

Hemolysin produced by Vibrio hollisae (Vh-rTDH), which is related to the thermostable direct hemolysin (Vp-TDH) of Vibrio parahaemolyticus, was studied. Vh-rTDH was purified by successive column chromatographies on diethylaminoethyl-cellulose and an immunoaffinity column coupled with anti Vp-TDH immunoglobulin. The purified toxin was homogeneous, as demonstrated by conventional and sodium dodecyl sulfate–polyacrylamide gel electrophoresis (PAGE). The molecular weight of Vh-rTDH was slightly smaller than that of Vp-TDH, as determined by sodium dodecyl sulfate – slab gel electrophoresis. Conventional PAGE also showed a difference between Vh-rTDH and Vp-TDH. Vp-TDH and Vh-rTDH showed different lytic activities on erythrocytes from various animals, in particular chicken, sheep, and calf. The hemolytic activity of Vh-rTDH was heat labile when heated at 70 °C for 10 min, unlike Vp-TDH. Immunological cross-reactivity between Vh-rTDH and Vp-TDH was demonstrated by both the Ouchterlony test and neutralization test.
Oosporogenesis by Lagenidium giganteum: induction and maturation are regulated by calcium and calmodulin
Authors: Kerwin James L. , Washino Robert K.
Published: May 2010

Induction and maturation of the sexual stage (oospores) of the facultative mosquito parasite Lagenidium giganteum (Oomycetes: Lagenidiales) are complex developmental processes regulated by calcium-dependent events. Use of developmentally synchronized cultures of L. giganteum allowed stage-specific disruption of calcium metabolism. A calcium chelator (EGTA), an ionophore (chlortetracycline), and inhibitors of the calcium-binding protein calmodulin (dibucaine, trifluoperazine, chlorpromazine) disrupted several discrete developmental steps associated with oosporogenesis: induction of antheridia, gametangial fusion, meiosis, oospore wall formation, and subsequent spore maturation. Extracellular calcium is necessary for oosporogenesis to proceed normally and under some conditions magnesium has a synergistic effect with calcium on oospore induction. Results are discussed in relation to calcium mediation of fusion events in a number of model membrane and biological systems.
Bacteriology of the oral cavity of BALB/c mice
Authors: Trudel L. , St-Amand L. , Bareil M. , Cardinal P. , Lavoie M. C.
Published: May 2010

To be used as a model in dental research, an animal must fulfil experimental needs and information on the composition and variation of its oral flora must be available. Only limited data are available on the indigenous oral bacterial flora of BALB/c mice. In this work, a total of 671 isolates from different sites (saliva, tongue, teeth, and mucosa) of the oral cavity of BALB/c mice were identified. Only 18 different species were isolated, which indicates the relative simplicity of the flora. The predominant species of the total cultivable flora were "Lactobacillus muritius" (38%), Staphylococcus aureus (37%), Streptococcus faecalis (8%), Staphylococcus sciuri (4%), and Escherichia coli (3%). The other species each represent less than 2% of the flora. "Lactobacillus murinus" is found in greater proportion on mucosa than in the other sites, Staph. aureus predominates in saliva, and Strep. faecalis was found in greater proportion in tooth samples. Statistical analyses, using the minimum percentage of similarity, indicate that there is some variation among the microflora of different mice but that this difference is smaller for mice from the same lot. These results set the basis for the study of the variations of the indigenous oral microflora of BALB/c mice under different conditions.
Family outbreak of gastroenteritis due to Yersinia enterocolitica serotype 0:3 from well water
Authors: Thompson J. Stephen , Gravel Michael J.
Published: May 2010

Yersinia enterocolitica serotype 0:3, biotype 4, has been isolated from two family members with diarrhea and from the well used as a source of their drinking water.
The ultrastructure of Methanothrix concilii, a mesophilic aceticlastic methanogen
Authors: Beveridge Terry J. , Patel Girish B. , Harris Bob J. , Sprott G. Dennis
Published: May 2010

Methanothrix concilii strain GP6 consists of a chain of rod-shaped cells, ca. 2.5 μm in length and 0.8 μm in width, which are encased in a tubular proteinaceous sheath. The sheath is composed of annular hoops, ca. 8.0 nm wide and 9.0 nm thick, which are stacked together to form the tube. The ends of the sheath, and therefore the cell filament, are blocked by single, multilayered, 13.5 nm thick, circular plates, designated as "spacer plugs," which contain a series of concentric rings; these also separate the individual cells within each filament. Each cell is therefore bounded by a tubular section of sheath and two spacer plugs. Completely encapsulating each cell, and lying between the sheath and cell, is an amorphous granular matrix. Overlying the plasma membrane and surrounding each protoplast is a thin veil of material which resembles a cell wall, but which is unable to maintain the rod shape when cells are extruded from the sheath.
Aerobic degradation of choline by Proteus mirabilis: enzymatic requirements and pathway
Authors: Sandhu Sukhvinder S. , Chase Jr. Theodore
Published: May 2010

Cleavage of choline to trimethylamine and acetaldehyde by extracts of Proteus mirabilis requires both particulate and soluble protein fractions, K+, and a bound divalent metal cation. The reaction shows a long lag period, abolished only by preincubation of the particulate fraction in the complete reaction system. The two-carbon fragment produced is acetaldehyde; choline cleavage appears to be tightly coupled to dismutation of the acetaldehyde to ethanol and acetate, as indicated by stimulation by NAD+, ADP. and Fe2+ and inhibition by reagents reacting with acetaldehyde. The system is thus similar to that previously described in anaerobes (Desulfovibrio, Clostridium). Attempts to demonstrate a cobamide coenzyme requirement (as in the similar ethanolamine ammonia-lyase reaction) were unsuccessful; the reaction was carried out by fractions devoid of vitamin B12 activity (not supporting growth of Lactobacillus leichmannii) and insensitive to light.
Interferences bacteriennes au niveau cutane chez la souris «hairless» dixénique
Authors: Barc M. C. , Bourlioux P. , Boureau H. , Nerbone F. , Costa E. Wasconcellos da
Published: May 2010

Bacterial colonizaion of the digestive tract and the skin was studied over a 3-week period in a group of 10 germfree HRS mice using Staphylococcus epidermidis, Staphylococcus aureus, and Pseudomonas aeruginosa. Sequential utilization of two strains allowed us to carry out six assays and to show the presence of interference phenomena during colonization of the skin. When P. aeruginosa was given after challenge with S. aureus or S. epidermidis, it did not colonize the skin. If the first challenge was done with P. aeruginosa, this bacteria was eliminated within 10 days by S. aureus and S. epidermidis on the skin, but it succeeded in colonizing the digestive tract. When the first challenge was done with S. aureus, colonization of the skin and the digestive tract with S. epidermidis was prevented, whereas these two species were found in association when S. aureus was given in second place. None of the in vitro assays (mixed culture, bacteriocin production, adherence inhibition, antimicrobial activity) could explain the in vivo observations.
Ascorbic acid specific utilization by some yeasts
Authors: Costamagna Lucia , Rosi Iolanda , Garuccio Isabella , Arrigoni Oreste
Published: May 2010

One hundred and eighty strains of yeasts belonging to 17 genus and 53 species were screened for their ability to grow on ascorbic acid and iso-ascorbic acid as the sole carbon source. Most of the tested strains (157) were unable to grow on either compound. Strains of seven species of the genus Cryptococcus, of two Candida species, of Filobasidiella neoformans, Trichosporon cutaneum, Lipomyces starkeyi, Hansenula capsulata, and one strain of Aureobasidium pullulans were able to grow on ascorbic as well as on iso-ascorbic acid. Conversely, four strains of Aureobasidium pullulans, Candida blankii, and Cryptococcus dimennae could use only ascorbic acid for growth.
Growth and hemolysin production by Haemophilus pleuropneumoniae cultivated in a chemically defined medium
Authors: Maudsley James R. , Kadis Solomon
Published: May 2010

A chemically defined medium (CDM) has been developed which supports both growth and hemolysin production by Haemophilus pleuropneumoniae. Although the growth rate in stationary cultures was substantially slower in CDM than in trypticase soy broth plus 0.6% yeast extract (TSBYE) and slightly slower than in heart infusion broth (HIB), extracellular hemolysin activity in CDM was slightly higher than in HIB and 16-fold greater than in TSBYE. Maximum hemolytic activity was produced in CDM in early to mid log phase of growth. Hemolytic activity in sterile, cell-free culture supernatant fluids persisted for over 10 days at 4 °C and 3–5 days at 37 °C, but was completely destroyed at 56 °C after 30 min. Total hemolysin inactivation was also achieved in the presence of trypsin or pronase (10 units/mL), but no decrease in hemolytic activity was noted in the presence of DNase or RNase. Iron had little effect on the hemolytic activity in the early stages of growth. However, in the later stages of growth, iron had a pronounced effect with hemolyic activity decreasing as the iron concentration increased from 1 to 500 μM. None of these iron concentrations had any effect on the hemolytic activity when added directly to prepared cell-free culture supernatant fluids. The extracellur hemolysin produced by H. pleuropneumoniae in CDM appears to be a heat-labile protein the activity of which is influenced by iron at certain phases of growth.
Metabolic stability of Phytophthora cinnamomi Rands in Western Australia
Authors: Hart R. M. , Keast D. , Smythe G.
Published: May 2010

Ten isolates of Phytophthora cinnamomi Rands from Western Australia were tested for metabolic variation using a commercial miniaturized biochemical system developed for bacteriology. The isolates included the two mating strains, and had been maintained in the laboratory for various times. The isolates were tested before and after repeated passaging on solid media. Statistical analysis of the biochemical results showed no major differences between the isolates, and for the most part they appear to be stable in cultivation. However, there were small passage effects on some of the media, particularly with glucose utilization.
Sheath disassembly in Methanospirillum hungatei strain GP1
Authors: Sprott G. Dennis , Beveridge Terry J. , Patel Girishchandra B. , Ferrante Giulio
Published: May 2010

Sheaths of Methanospirillum hungatei are very resilient structures and consist of circumferential rings, which have been likened to the hoops of a barrel. The isolated sheaths are dramatically disassembled to the individual hoops upon treatment with β-mercaptoethanol at 90 °C. Sheath disassembly resulted in a large decrease in suspension turbidity and a release of approximately 10% of sheath protein in the form of 4.6 to 7.0 kiloDalton (kDa) peptides. These are referred to as "glue peptides" to suggest a function in linking the hoops together to form the intact sheath. The liberated hoops consisted of a protein surface array crystallized on a matrix material. Intact sheaths, or hoops largely freed of the glue peptides, could be solubilized at 90 °C by (i) a combination of β-mercaptoethanol and sodium dodecyl sulfate, (ii) by alkaline conditions of pH 12 or more, or partially (iii) by carbonate anion at pH 11. Fractionation by liquid chromatography of hoops solubilized by alkaline conditions of pH 12.6 revealed major polypeptides of about 24 and 45 kDa; a smaller peak occurred at 12 kDa. Based on the dimensions of the unit cell of the crystalline array, we suggest that two copies of the 24-kDa polypeptide form the 5.6 × 2.8 nm unit cell as a dimer, which then tends to form larger aggregates. The 2.8-nm subunit may be a dimer of the 12-kDa species. Sheaths of M. hungatei strain JF1 exhibited a similar polypeptide profile, but in this case, the 45-kDa species predominated.
Immunocytochemical localization of antigen-binding sites in the cell surface of two ascomycete fungi using antibodies produced against fimbriae from Ustilago violacea and Rhodotorula rubra
Authors: Benhamou Nicole , Ouellette G. B. , Gardiner R. B. , Day Alan W.
Published: May 2010

Cross-reactivity between antisera produced against fimbriae of either Ustilago violacea (Pers.) Fuck. (AU) or of Rhodotorula rubra (Demme) Lodder (AR) and cell surface proteins of two ascomycete fungi, Ascocalyx abietina (Lagerberg.) Schlaepfer-Bernhard and Ophiostoma ulmi (Buism.) Nannf., was revealed by means of dot-immunobinding and immunocytochemical methods. Following treatment with antiserum AR, the walls, septa, and plasma membrane of A. abietina and O. ulmi cells (the latter either in culture or grown in elm wood sections) were appreciably labeled by gold particles, but the labeling intensity was always found to be greater over the plasma membrane. The fibrillar sheath surrounding cells of A. abietina reacted with antiserum AU while all other structures did not. No significant labeling with this antiserum occurred over cells of O. ulmi indicating that they either lacked these antigens or that these were more easily removed during the fixation process. Possible explanations for the differences obtained with antisera AR and AU are discussed along with an overview of the potential use of these antisera in conjunction with the protein A – gold method in studies of host–parasite interrelationships.
Role of chitin in the survival of Vibrio parahaemolyticus at different temperatures
Authors: Karunasagar I. , Venugopal M. N. , Karunasagar Indrani , Segar K.
Published: May 2010

Washed cells of Vibrio parahaemolyticus declined in numbers when incubated in phosphate-buffered saline for 6 h at different temperatures. Addition of chitin flakes to phosphate-buffered saline not only helped the organism to survive, but also resulted in an increase in cell numbers, particularly at 10 °C. The effect of chitin could not be simulated by N-acetylglucosamine, yeast extract, starch, or casein.
Microbiological quality of bottled water sold in Canada
Authors: Warburton Donald W. , Peterkin Pearl I. , Weiss Karl F. , Johnston Murray A.
Published: May 2010

The microbiological quality of bottled water sold in Canada was evaluated. A total of 114 lots of bottled water, both domestic and imported, were analyzed for aerobic colony count, coliforms, fecal coliforms, and Escherichia coli. No fecal coliforms or E. coli were found. Nineteen (46%) of the 41 lots of domestic purified water were found to exceed aerobic colony count standards and another lot exceeded coliform standards. One lot each of domestic and imported mineral water exceeded coliform standards. If mineral water were governed by the aerobic colony count standards for bottled water, then five lots each of both domestic and imported mineral water would have been found to be unsatisfactory. More surveillance of the bottled water industry in Canada is recommended.
Competitive development of Thiocapsa roseopersicina and Chlorobium phaebacteroides in Lake Kinneret
Authors: Eckert W. , Frevert T. , Dan T. Bergstein-Ben , Cavari B. Z.
Published: May 2010

The beginning of the bloom of Chlorobium phaeobacteroides in Lake Kinneret is accompanied by the occurrence of cells of Thiocapsa roseopersicina, which subsequently disappear. It was found that Thiocapsa requires relatively high light intensities (50–100 μE∙m−2∙s−1) for growth which proved to be higher than that for Chlorobium. Acetate played an important role in the growth of Thiocapsa only when the organisms were exposed to light intensities which were not optimal for photosynthesis. Optimum total sulfide concentrations for growth of Thiocapsa were found to be in the range of 1–3 mM. Considering the differential uptake of the reduced sulfur components H2S and HS−, a preference for HS− is suggested. It seems further likely that H2S inhibits growth at concentrations above 1 mM, independent of the pH. Compared with Chlorobium, favourable conditions for Thiocapsa at the beginning of the bloom period are due to low in situ concentrations of H2S, which prevent rapid development of Chlorobium.
Utilization of octopine by marine bacteria isolated from mollusks
Authors: Dion P.
Published: May 2010

Three bacteria were isolated from mussels and oysters by selection on octopine as the sole carbon and nitrogen source. The isolates exhibited an absolute requirement for sodium ions that established their marine character. Morphological and physiological tests indicated that they were related to the marine pseudomonads. They differed from each other with respect to growth patterns on octopine.
Production and properties of Beauveria bassiana conidia cultivated in submerged culture
Authors: Thomas K. C. , Khachatourians G. G. , Ingledew W. M.
Published: May 2010

Under submerged growth in a defined medium (TKI broth), the entomopathogenic fungus, Beauveria bassiana, produced conidia; it produced only blastospores in complex media. Production of such "submerged" conidia depended on the nature of the carbon source and the presence of nitrate as a nitrogen source. Maximum yield of conidia (5 × 108 mL) was obtained when glucose was the carbon source and when the glucose to nitrate ratio was 5:1. Other carbon sources gave rise to both conidia and blastospores. Reducing the phosphate concentration resulted in the production of conidia which resembled "aerial" conidia in morphology and germination rates. The surfaces of "submerged" conidia were relatively smooth, but had a tendency to acquire the rough, warty, brittle surface characteristics of aerial conidia. Blastospores produced in defined media gave rise to conidia through microcycle conidiation without going through the vegetative phase of growth. In more complex media, blastospores did not undergo microcycle conidiation.
Freeze-fracture electron microscopic studies of age-related plasma membrane changes in Sporothrix schenckii
Authors: Maeda Manabu , Kitajima Yasuo , Shikano Yukiko , Mori Shunji
Published: May 2010

Characteristics of the plasma membrane of Sporothrix scheckii cells as revealed by freeze-fracture techniques have been classified into eight types (Y1, Y2a, Y2b, Y3a, Y3b, Y4a, Y4b, and Y5) in yeastlike cells grown under the following two conditions: brain heart infusion agar medium at 27 °C, and brain heart infusion agar medium at 37 °C. Type Y1 cells are yeastlike cells having smooth plasma membranes without any invagination. Typical characteristics of the other types are as follows: type Y2a, smooth plasma membranes with few trenchlike invaginations; type Y2b, wavy plasma membranes with few oval or irregularly formed invaginations; type Y3a, plasma membranes with many randomly distributed trenchlike invaginations; type Y3b, plasma membranes with many cocoonlike or irregularly formed invaginations; type Y4a, plasma membranes with longer trenchlike invaginations; type Y4b, plasma membranes with irregularly formed, enlarged invaginations; and type Y5, smooth or wavy plasma membranes with aggregations of intramembranous particles and with many vacuoles between cell walls and plasma membranes or in the cytoplasm in some cells. By counting the proportion of each type of yeastlike cell under the two conditions and with different cultivation periods, it appears that plasma membrane types change as aging progresses in the following order: type Y1, Y2a, Y3a, Y4a, and Y5 in conidia and type Y1, Y2b, Y3b, Y4b, and Y5 in yeastlike vegetative cells. These observations provide us with an important advantage when studying the effects of antifungal agents on the plasma membrane of Sporothrix scheckii, as it is important to know the natural course of changes in membrane structure during aging.
Establishment by mutation of a new pathway of serine metabolism in Arthrobacter P1
Authors: Poulin D. , Newman E. B.
Published: May 2010

Arthrobacter P1 grew readily with glucose or glycine as sole carbon source, but not with L-serine. However, mutants using L-serine were readily isolated. These synthesized hydroxypyruvate reductase and serine/α-ketoglutarate transaminase constitutively. We suggest that Arthrobacter P1 as originally isolated had the structural genes necessary to form these enzymes, but was not able to produce enyzmes from them.
Comparison of bacterial counts obtained from naturally contaminated foods by means of Stomacher and blender
Authors: Purvis U. , Sharpe A. N. , Bergener D. M. , Lachapelle G. , Milling M. , Spiring F.
Published: May 2010

Four Regional Health Protection Branch laboratories each compared aerobic colony counts obtained after "stomaching" and blending, for a minimum of 10 samples in each of the seven food groups: dry pastas; chocolate and cocoa powders; frozen entrees (macaroni and cheese, chow mein, chop suey, fried rice, seafood casseroles, and Salisbury steak); nonfat dry milk; shrimp and crabmeats; spices; and breakfast sausages. Overall, counts obtained after using the Stomacher were equivalent to or higher than counts obtained after using the blender in 73% of the comparisons (α = 0.05). Where differences existed, counts obtained after using the Stomacher tended to be higher than counts obtained after using the blender from milk powder and lower from sausage. Aerobic colony counts from these foods are not unacceptably biased when obtained by Stomacher.
Metabolism of Escherichia coli injured by copper
Authors: Domek Matthew J. , Robbins John E. , Anderson Mark E. , McFeters Gordon A.
Published: May 2010

Escherichia coli injured by copper in carbonate buffer simulating the drinking water environment showed decreased oxygen utilization. Oxygraph measurements revealed that copper-injured bacteria had a rate of oxygen utilization that was less than 25% of that of control cells. Respirometry experiments measured rates over a longer period of time and showed similar trends. Nuclear magnetic resonanance spectroscopy (13C nmr) and gas chromatography were used to identify differences in metabolism between healthy and injured populations of E. coli. The rate of glucose utilization by injured cells under anaerobic conditions was 64% of that of healthy cells. The rates of lactate and ethanol accumulation were 88 and 50% of the control, respectively. The 13C nmr studies of oxygenated cultures revealed differences in the accumulation of acetate and glutamine. Aerobic utilization of glucose and succinate by injured cells were 87 and 21% of the rate of the controls, respectively. Additional studies revealed injured cells had a decreased ability to reduce 2-(p-iodophenyl)-3-(p-nitrophenyl)-5-phenyltetrazolium chloride (INT) with a variety of carbohydrate substrates. Injured cells reduced greater quantities of INT than healthy cells when NADH was used as a substrate. A comparison of metabolic end products suggested that injured cells also had considerable differences in carbon flow compared with healthy cells.
Phosphate-selective porins from the outer membranes of fluorescent Pseudomonas sp.
Authors: Poole Keith , Parr Jr. Thomas R. , Hancock Robert E. W.
Published: May 2010

Phosphate starvation induced oligomeric proteins from the outer membranes of Pseudomonas fluorescens, Pseudomonas putida, Pseudomonas aureofaciens, and Pseudomonas chlororaphis were purified to homogeneity. The incorporation of the purified proteins into planar lipid bilayer membranes resulted in stepwise increases in membrane conductance. Single channel conductance experiments demonstrated that these proteins were all capable of forming small channels, similar to the Pseudomonas aeruginosa phosphate porin protein P, with average single channel conductances in 1 M KCl of between 233 and 252 pS. Single channel conductance measurements made in salts of varying cation or anion size indicated that the channels were uniformly anion selective. The measurement of single channel conductance as a function of KCl concentration revealed that all channels saturated at higher salt concentrations, consistent with the presence of an anion-binding site in the channel. Apparent Kd values for Cl− binding were calculated and shown to vary only twofold (180–297 mM) among all channels, including protein P channels. Phosphate competitively inhibited chloride conductance through these channels with apparent I50 values of between 0.59 and 2.5 mM phosphate at 40 mM Cl− and between 9.7 and 27 mM phosphate at 1 M Cl−. These data were consistent with the presence of a phosphate-binding site in the channels of these phosphate-regulated proteins. Furthermore, they indicated that these channels exhibit at least a 20- to 80-fold higher affinity for phosphate than for chloride.
Effect of ethanol on the glucose-induced movements of protons across the plasma membrane of Saccharomyces cerevisiae NCYC 431
Authors: Juroszek Jean-Regis , Feuillat Michel , Charpentier Claudine
Published: May 2010

The study of glucose-induced proton fluxes in Saccharomyces cerevisiae NCYC 431 showed a decrease of proton net efflux by ethanol across the plasma membrane of energized cells. Furthermore a negative net proton efflux (an influx) occurred from a given ethanol concentration (between 1.3 and 1.5 M) whatever the experimental conditions used, thus allowing the definition of a nil–net exchange step where no net movement of protons across the plasma membrane could be observed. A new technique of ethanol tolerance determination in yeast based upon a correlation for the same ethanol concentration between both the collapse of the proton gradient and the growth cessation in cultures supplemented with ethanol after 8 h incubation was proposed. The defined method also showed a cumulated effect of temperature and ethanol on Saccharomyces cerevisiae NCYC 431.
Production of cytotoxin by clinical strains of Pseudomonas aeruginosa
Authors: Baltch Aldona L. , Obrig Tom G. , Smith Raymond P. , Hammer Mark C. , Conroy Joseph V. , Lutz Frieder
Published: May 2010

Presence of cytotoxin was studied in extracts of 57 strains of Pseudomonas aeruginosa (46 bacteremia, 4 environmental, and 7 Fisher immunotype), 10 Pseudomonas species, and 7 nonpseudomonas isolates. Cytotoxin was identified by Western immunoblot in extracts of all P. aeruginosa isolates. None of the Pseudomonas species or nonpseudomonas isolates were shown to produce this protein. No immunologic cross-reactivity was observed between cytotoxin antibody and P. aeruginosa alkaline protease, toxin A, or elastase. In partially purified extracts of two bacteremia strains and PA 158 (parent strain for cytotoxin production), detection of cytotoxin by Western immunoblot was correlated with biological activity, as measured by the cell swelling assay. Cytotoxin appears to be produced by all strains of P. aeruginosa and biological activity can be demonstrated in extracts of the strains tested. This biological activity is neutralized by specific antibody. Because of its known marked cytotoxic effect on most eukaryotic cells, P. aeruginosa cytotoxin might be an important factor in the pathogenesis of P. aeruginosa infections.
Selective hybridization of wine yeasts for higher yields of glycerol
Authors: Eustace Rosanne , Thornton R. J.
Published: May 2010

Wines that are lacking in body may be improved by the presence of greater amounts of glycerol. Wine yeast strains vary in their ability to produce glycerol. A programme of hybridizing yeast strains while selecting for increased production of glycerol was undertaken. Three generations of hybridization resulted in yeast strains which produced 10–11 g glycerol/L compared with 3.0–6.6 g/L produced by the wine yeast strains of the original breeding stock. Industrial-scale winemaking confirmed the ability of two hybrid strains to produce similar amounts of glycerol to those observed in laboratory-scale fermentations. The activity of the enzyme glycerol-3-phosphate dehydrogenase was measured in crude extracts of two breeding stock wine yeasts and in two final generation hybrid strains. The observed activities were lower in the products of the hybridization programme than in the original wine yeast strains. Two alternative explanations are suggested. (i) Selective hybridization may select for the alleles of the gene which codes for an alcohol dehydrogenase I isozyme which has a lower activity resulting in increased glycerol production. (ii) Phospholipid synthesis is reduced and the glycerol-3-phosphate, which is the major precursor of phospholipids in yeasts, accumulates as glycerol.
Inhibition of yeast respiration and fermentation by benomyl, carbendazim, isocyanates, and other fungicidal chemicals
Authors: Chiba Mikio , Bown Alan W. , Danic David
Published: May 2010

The inhibition of yeast (Saccharomyces cerevesiae) metabolism by fungicidal chemicals was investigated. Glucose- or ethanol-dependent yeast respiration was measured with an oxygen electrode, and manometric determination of carbon dioxide release was used to measure fermentation. Both respiration and fermentation were inhibited more by benomyl than by identical molar concentrations of its breakdown product, carbendazim. Butyl isocyanate, another benomyl breakdown product, inhibited respiration more but inhibited fermentation less than the parent compound. Of the isocyanates tested, hexyl isocyanate was the most inhibitory towards both activities. Captan was more active and iprodione less active than benomyl. Because benomyl rapidly broke down to carbendazim when it was prepared in 80% ethanol, only 59% of the dissolved benomyl was intact when it was added to yeast to determine its effect on respiration or fermentation.
Production of 3,4-dihydroxybenzoic acid by Azomonas macrocytogenes and Azotobacter paspali
Authors: Collinson S. Karen , Doran James L. , Page William J.
Published: May 2010

Four strains of Azomonas macrocytogenes and a strain of Azotobacter paspali were found to produce a common extracellular, iron-binding, phenolic compound. This compound was purified from cell-free culture supernatant fluids and chemically identified as 3,4-dihydroxybenzoic acid (protocatechuic acid). 3,4-Dihydroxybenzoic acid was produced by cells growing in a simple defined medium containing acetate and glucose or sucrose as sole carbon sources. This compound promoted the solubilization of iron from the minerals olivine, glauconite, pyrite, and marcasite. Mineral-free medium prepared by preincubation with olivine or glauconite as the only iron source supported enhanced growth yields of Azomonas macrocytogenes (ATCC 12334) when 3,4-dihydroxybenzoic acid was present during the preincubation period. This suggests that 3,4-dihydroxybenzoic acid may play a role in solubilizing iron from some natural iron sources; however, 3,4-dihydroxybenzoic acid can not be considered a true siderophore since it was produced by Azomonas macrocytogenes and Azotobacter paspali growing in iron-limited and iron-sufficient medium.
Inhibition of melanin synthesis in the black yeast Phaeococcomyces sp. by growth on low pH ascorbate medium: production of spheroplasts from "albinized" cells
Authors: Butler Michael J. , Lachance Marc-André
Published: May 2010

The black yeast Phaeococcomyces sp. produces pentaketide-based melanin constitutively, resulting in a green–black colony colour on commonly used isolation and culture maintenance agar media. Pentaketide melanins are produced by a multi-enzyme pathway, beginning with the cyclization of conjoined acetate molecules and ending with the polymerization of the final phenolic precursor, dihydroxynapthalene, into melanin. A low pH medium, which contains 0.1% ascorbic acid, causes complete inhibition of melanin formation, resulting in a white colony apearance similar to that of albino mutants of Phaeococcomyces sp. Melanized Phaeococcomyces sp. cells resisted enzymatic cell wall digestion, and spheroplasts could not be formed. In contrast, spheroplasts were produced from cells "albinized" by growth on the low pH medium. Inhibition of melanogenesis in other fungi, by growth on low pH ascorbate medium, was found to be specific to pentaketide melanin producers.
Antagonistic effect exerted by three strictly anaerobic strains against various strains of Clostridium perfringens in gnotobiotic rodent intestines
Authors: Yurdusev Nevzat , Nicolas Jean Louis , Ladire Monique , Ducluzeau Robert , Raibaud Pierre
Published: May 2010

Our purpose was to study bacterial antagonism between a limited number of strictly anaerobic strains and Clostridium perfringens in the intestinal tract of gnotobiotic rodents. Gnotobiotic mice harboring a Bacteroides thetaiotaomicron, a Fusobacterium necrogenes, and a Clostridium sp. strain were protected against pathogenic B, C, and D C. perfringens serotypes. A drastic antagonistic effect of this three-strain association was also observed against a nonpathogenic C. perfringens serotype A (CpA). It was less efficient in gnotobiotic rats than in mice and less efficient in gnotobiotic mice fed an autoclaved diet than in mice fed the same diet sterilized by irradiation. No diffusible inhibitory substances against CpA were detected in feces of gnotobiotic mice harboring the three antagonistic strains, and no nutrient depletion was demonstrated in filtrates prepared from 10-fold diluted feces of these mice. In vitro mixed cultures of the three antagonistic strains failed to inhibit growth of CpA, whereas CpA did not multiply in a 10-fold diluted feces from gnotobiotic mice. A reverse correlation between the initial number of antagonistic strains and the division number of CpA was determined using serially diluted fecal suspensions. Thus, large numbers of viable cells of both antagonistic strains were required to inhibit the target strain in fecal suspensions as was also found in gnotobiotic mice intestines. However, no diffusible inhibitory substance was detectable nor could depletion of growth factors be identified as causing antagonism. Whatever factors that may be responsible for antagonism were found to be influenced by the host and its diet.
Evidence that available energy is a limiting factor in the bacterial corrosion of mild steel by a Pseudomonas sp.
Authors: Obuekwe C. O. , Westlake D. W. S. , Plambeck J. A.
Published: May 2010

Corrosion of mild steel coupons in cultures of Pseudomonas sp. no. 200 was inhibited (polarized) when the available energy was low, but was depolarized at high available substrate levels. Thus, the corrosion of the steel coupons which was partially inhibited in produced water was depolarized (made active) by the addition of 900 mg sodium lactate per litre. Also sustained corrosion of the steel coupons was only obtained at a high substrate level (1800 μg lactate∙L−1), and at lower levels (300 and 600 μg∙L−1) it was inhibited. Therefore, available energy is a limiting factor in bacterial corrosion of steel.
Neutral proteinases from two mucoraceous fungi: a comparative study
Authors: Balasubramanian R. , Manocha M. S.
Published: May 2010

Neutral proteinases from the mycelial extracts of two mucoraceous fungi, Choanephora cucurbitarum and Phascolomyces articulosus, were purified by salting out, heat treatment, and Sephadex G75 and DEAE-Sephadex chromatography. The proteinase from P. articulosus possessed higher molecular weight (Mr 25 000) as compared with that from C. cucurbitarum (Mr 15 000). The enzyme from both fungi hydrolyzed casein rapidly, but the proteinase of P. articulosus registered higher carboxy-peptidase and leucine aminopeptidase activities than that of C. cucurbitarum. Benzoyl-arginine p-nitroanilide was not hydrolyzed by either of them. Both enzymes had a pH optimum of 7.0, were stable up to 40 °C, and were inhibited by EDTA and N-α-p-tosyl-L-lysine chloromethyl ketone, more so by the latter. The proteinase of C. cucurbitarum was also sensitive to diisopropyl fluorophosphate, benzamidine, L-1-tosylamide 2-phenylethyl chloromethyl ketone, leupeptin, and soybean trypsin inhibitor. Cysteine and dithiothreitol did not have any effect on the enzyme activity. The P. articulosus proteinase was more sensitive to almost all the heavy metal ions tested than the neutral proteinase of C. cucurbitarum.