bluuebunny/crossref_metadata_2025 huggingface dataset:
The regular hexagonal surface layer of Halobacterium cutirubrum: a honeycomb network
Authors: D'Aoust Jean-Yves , Kushner Donn J.
Published: February 2010

The regular surface pattern of Halobacterium cutirubrum, as studied from replicas, appears to be made up of spherical subunits in hexagonal array. Low-beam intensity studies of cells dried from salt solutions revealed a regular honeycomb network containing hexagonal holes 9.5 to 11.0 nm in diameter with a center-to-center repeat distance of 15.5 to 17.0 nm. These structures appeared to be negatively stained by NaCl or heavy cations adsorbed from the growth medium. This network shares a number of common features with the perforate outer layer of Lampropedia hyalina.
Some characteristics of fluorescent pseudomonads isolated from surface waters and capable of growth at 41C
Authors: Hoadley A. W. , Ajello Gloria
Published: February 2010

The occurrence in surface waters of fluorescent pseudomonads other than Pseudomonas aeruginosa which are capable of growth at 41C is reported. Among 29 isolates subjected to selected tests, some strains were clearly distinguishable from P. aeruginosa while others possessed characteristics in common with both P. aeruginosa and certain non-fluorescent aerobic pseudomonads. The pathogenicity to mice of representative strains injected intraperitoneally varied within a range reported in the literature for P. aeruginosa, but differed by at least one order of magnitude from that of a control strain of P. aeruginosa examined.
Communal growth response of a heat-injured strain of Escherichia coli
Authors: Roth L. A. , Stiles M. E. , Clegg L. F. L.
Published: February 2010

A phenomenon referred to as communal growth response was observed with heat-injured cells of E. coli strain SA603 plated on selective media for coliforms. Excessively low counts were obtained at dilutions designed to give between 30 and 300 colonies per plate. Sublethal heat treatment of this strain appears to result in two types of injured cells; those able to grow on selective media when present in excess of about 400/Petri dish (15 × 100 mm) and those unable to grow on selective media even when present in concentrations above the threshold level of 400/Petri dish.
Oxidation of copper (II) selenide by Thiobacillus ferrooxidans
Authors: Torma Arpad E. , Habashi Fathi
Published: February 2010

Thiobacillus ferrooxidans can derive its energy from the oxidation of copper selenide. In this metabolic oxidation process, copper goes into solution and elemental selenium is deposited.
Dissimilatory metabolism of nitrate by the rumen microbiota
Authors: Jones G. A.
Published: February 2010

A mixed culture of bovine rumen microorganisms was incubated anaerobically, under conditions likely to support growth, with added nitrate and in the presence of several potential hydrogen donors known to be intermediates in the rumen fermentation. Reduction of nitrate via nitrite to ammonia was observed but there were marked differences in the relative rates and extent of nitrate and nitrite reduction in the presence of different hydrogen donors. The hydrogen donors were ranked in decreasing order of overall effectiveness for the complete reduction of nitrate and nitrite: formate > hydrogen > glucose [Formula: see text] lactate > succinate. Methane production in the cultures was markedly depressed in the presence of nitrate. The identification by gas chromatography of nitrous oxide in the gas phase of cultures containing nitrate and incubated with hydrogen, glucose, or lactate showed that the microbiota was capable of denitrification. The quantitative significance of denitrification as a pathway of nitrate dissimilation by rumen microorganisms, however, is probably small.
Immunological analysis of particulate antigens of human leukemia
Authors: Lee Rosanna , Kwapinski J. B. G.
Published: February 2010

Numerous hexagonal virus-like particles were detected in, and isolated from, liver and spleen obtained from eight autopsies of human leukemia, diagnosed as different forms of the disease. These particles were purified by a combination of the continuous particle electrophoresis and isopycnic gradient centrifugation. The purified virus-like particles reacted with rabbit antisera produced against the purified particulate antigens of leukemia but not with the extracts obtained from different "normal" human liver and spleen, as examined by the immunodiffusion and immunoferritin techniques. The experimental evidence indicates a biological association of the particulate antigens with human leukemia.
Ultraviolet light induced thymine dimers and repair processes in the alga Eudorina elegans
Authors: Kemp C. L. , Tsao M. S. , Thorson G.
Published: February 2010

A fraction of the cellular DNA of the colonial green alga Eudorina elegans strain 1193 can be specifically labeled with 3H-thymidine but not by 3H-thymine. Ultraviolet (UV) irradiation of E. elegans leads to the production of thymine dimers as determined by extraction, hydrolysis, and chromatography of 3H-thymidine-labeled cells. Removal of dimers occurs by processes involving visible light (photoreactivation), but dark repair (excision repair) has not been detected in the labeled fraction. A relationship between UV exposure and thymine dimer production has been determined.
Protein synthesis by the psychrophiles Bacillus psychrophilus and Bacillus insolitus
Authors: Bobier S. R. , Ferroni G. D. , Inniss W. E.
Published: February 2010

Protein synthesis by whole cells of two psychrophilic bacteria, Bacillus psychrophilus and Bacillus insolitus, directly corresponded to the growth of these organisms at 5, 20 and 30C, with a smaller total amount of growth and protein synthesis occurring at 30C than at 20C. When the effect of temperature on protein synthesis was examined using extracts, the capability to carry out poly U directed incorporation of 14C-L-phenylalanine into protein was inhibited by 30C as compared to 5C. The temperature sensitivity of the cell-free protein synthesizing systems was not due to the presence of heat-sensitive aminoacyl-tRNA synthetases. Investigation of the effect of separately heating at 30C washed ribosome (W-RIB) and supernatant (IS-100) fractions prepared from these microorganisms, followed by recombination and reaction at 15C, showed that the temperature sensitivity of the protein synthesis resided in the ribosomal fraction of the cells
Nitrogen fixation by Klebsiella grown in the presence of oxygen
Authors: Klucas Robert
Published: February 2010

Several facultative asymbiotic N2-fixing bacteria exhibited nitrogenase activity when grown in the presence of air and a limiting amount of fixed nitrogen. One isolate (S-4) identified as Klebsiella was examined in more detail for oxygen effects. Nitrogenase was not detectable in highly aerated submerged cultures but was detectable in shaken and continuous cultures at dissolved oxygen tensions of 3 and 10 mm of Hg respectively. No nitrogenase activity was found in cells from continuous cultures maintained at a dissolved oxygen tension of 15 mm of Hg or above. The nitrogenase activity in whole cells was not oxygen dependent but was oxygen tolerant.
Lactic acid production in milk and DNA homology relationships in the species Lactobacillus jugurt
Authors: Matteuzzi Diego
Published: February 2010

Genetic relatedness among strains of Lactobacillus jugurt with different acidifying activity in milk was assayed by DNA–DNA hybridization. All the strains tested were closely related genetically, deoxyribonucleic acid (DNA) homology ranging from 89 to 100%. "Acidity in milk," one of the differential characters, should be considered, therefore, to be of little diagnostic value.
Formation of asci with two diploid spores by diploid cells of Saccharomyces
Authors: Grewal N. S. , Miller J. J.
Published: February 2010

Fifteen yeast strains that produced predominantly two-spored asci were found to include three strains having no more than two nuclei per ascus. The progeny of the spores of these three strains were capable of sporulation without conjugation. Deoxyribonucleic acid (DNA) determinations showed that both vegetative cells and spores were diploid, indicating that nuclear division in the ascus is not reductional.A structure present in the intersporal space of a two-spored strain was defined morphologically by electron microscopy.
Absence of glucokinase in Methanomonas sp. as a cause for their inability to grow on glucose
Authors: Amemiya Kei
Published: February 2010

Many obligate autotrophic bacteria can be grown on glucose using a dialysis flow-through system. Methanomonas methanooxidans, an obligate methylotroph, exhibits many of the properties of an obligate autotrophic bacterium but we have been unable to grow it on glucose using dialysis. In the obligate autotrophic bacteria, the dialysis procedure seems to be removing a toxic product of glucose metabolism but this does not seem to be the case with the methylotroph. Enzymatic assays on a cell-free extract from methane-grown or methane plus glucose-grown cells showed only phosphoglucoisomerase activity, while glucokinase and glucose-6-phosphate dehydrogenase activity were not detected. Studies with resting cells showed that glucose was not oxidized, although the phosphate esters of glucose, fructose, ribose, and gluconate were oxidized. CO2 fixation occurred only in the presence of glucose-6-phosphate. The rate of oxygen consumed and CO2 fixed on glucose-6-phosphate were almost identical with that when methanol was used as the substrate. When the phosphate esters of glucose, fructose, and ribose were used as the sole energy source, only glucose-6-phosphate supported growth to any extent; in fact, the amount of growth was essentially the same as that obtained with methanol. The results from this study suggest that the inability of this organism to grow on glucose may be due to the absence of adequate glucokinase.
Microbial ecology of untreated and copper–chrome–arsenic treated stakes exposed in a tropical soil. 1. The initial invaders
Authors: Greaves H.
Published: February 2010

A study of the microbial ecology of copper–chrome–arsenic treated and untreated Pinus radiata and Eucalyptus regnans sapwood ground stakes exposed for a total of [Formula: see text] years is currently being made. The results presented in this report cover the initial colonization period during the first 7 months of exposure. Soft rot in the outer layers of both species of untreated wood occurs after only 1 month in the ground. Treatment with CCA prevents the early attack of pine but is not as effective in the eucalypt, nor does it appear to have a significant effect upon the diversity of microorganisms which colonize the two woods. For the first 2 months Penicillia are the predominating members of the population. Trichoderma viride, Paecilomyces fumo-roseus, and Cladosporium spp. are also frequently isolated. At 4 months more active soft-rotting fungi can be isolated, e.g. Chaetomium globosum and Humicola grisea, together with Fusaria and Phycomycetes. Bacteria colonize the stakes at a very early stage, the population changing little over this initial period of the study. Actinomycetes were not isolated until the wood had been in the ground for a month or more after which their importance in the population has steadily increased. Basidiomycetes were microscopically observed in sections of the stakes but have not been isolated to date.
Ultrastructure of Filobasidium Olive
Authors: Moore R. T. , Rij N. J. W. Kreger-van
Published: February 2010

Electron microscopy of the two species of Filobasidium show representative basidiomycete dolipores, but in which the pore-occluding material, instead of being a homogenous, electropaque, dome-shaped structure, is a flattened plate with dark edges and a lighter center. Parenthesomes in F. capsuligenum are represented by clusters of cone-shaped vesicles that appear to be anchored by microfilaments that pass into the pore-occluding plate. Parenthesomes are absent in F. floriforme but occasionally vesiculate endoplasmic reticulum (ER) is seen in the pore region. Other cell structures are also illustrated.
Purification and properties of L-asparaginase of Erwinia aroideae
Authors: Liu F. S. , Zajic J. E.
Published: February 2010

The intracellular enzyme, L-asparaginase, from aerobically grown Erwinia aroideae NRRL B-138 has been purified and some of its properties studied. Sonic treatment permitted recovery of 95% of L-asparaginase from cells. The crude cell lysate was purified 167-fold by means of ammonium sulfate fractionation and column chromatography on hydroxylapatite–cellulose, and DEAE–Sephadex. The specific activity of the most active fraction of L-asparaginase is 256 IU/mg protein. The enzyme has a broad pH activity profile with maximum at pH 9.0–9.5. The optimum temperature for enzyme reaction was determined to be 41 °C. The apparent activation energy is 11 000 cal/mole. The molecular weight of L-asparaginase was estimated by gel filtration to be 108 000.
Growth and ultrastructural differentiation of sporangia in Phytophthora palmivora
Authors: Christen Josef , Hohl Hans R.
Published: February 2010

Development of sporangia in Phytophthora palmivora Butler consists of two main stages. The first involves expansion of the sporangial initial to about the size of the mature sporangium, whereas the second is characterized by the differentiation of the expanded vesicle to the mature sporangium. Differentiation includes basal plug formation, secondary sporangial wall thickening, and apical papilla formation.Expansion of the sporangial initial appears to be mainly the result of cytoplasmic inflow from the mycelial mat coupled with surface growth of the vesicle wall. Basal plug formation terminates the phase of expansion. The process of plug formation involves deposition of wall-like material at the base of the expanded vesicle. The depositions, which grow from the periphery towards the center of the sporangiophore, are at first rather irregular in shape but eventually lead to complete occlusion, thus separating the immature sporangium from the sporangiophore. Sporangial wall thickening starts at the basal plug and progresses towards the developing apical papilla. Papilla formation is initiated by an apical bulge of the immature sporangium. The cytoplasm within the bulge is specialized and characterized mainly by populations of small (50–100 nm) and large (about 250 nm) vesicles, which appear to be involved in papilla formation. Papilla deposition resembles hyphal tip growth in the absence of cell expansion.
Preservation of Entomophthora protoplasts in liquid nitrogen
Authors: Tyrrell David , Sohi S. S. , Welton Mary A.
Published: February 2010

Protoplasts of Entomophthora spp. were satisfactorily preserved in liquid nitrogen after controlled-rate cooling to −40 °C. 5% Dimethyl sulfoxide was the preferred cryoprotectant.
Non-enzymic in vitro formation of nitrosamines by bacteria isolated from meat products
Authors: Collins-Thompson D. L. , Sen N. P. , Aris B. , Schwinghamer L.
Published: February 2010

The formation in culture of dimethyl- and diethyl-nitrosamine from sodium nitrite and secondary amines was brought about by Streptococcus species, but not by members of several other genera tested. This formation appears to be non-enzymic, pH dependent, and may be catalyzed by one or more bacterial metabolic products.
Virus-like particles in Mycoplasma hominis
Authors: Robertson Janet , Gomersall Margaret , Gill Peter
Published: February 2010

Virus-like particles of 350 Å have been observed intracellularly in a strain of M. hominis. This appears to be the first example of such particles within cells of the order Mycoplasmatales.
Studies on acid production during carbohydrate metabolism by extremely halophilic bacteria
Authors: Tomlinson Geraldine A. , Hochstein L. I.
Published: February 2010

Several strains of extremely halophilic bacteria produced pyruvate when grown in the presence of glucose. One, M6, formed pyruvate and acetate from glucose, galactose, lactose, fructose, and sucrose. The greatest accumulation of these acids occurred when cells were grown with glucose; in the presence of galactose or lactose, the appearance of acetate and pyruvate was transitory. Glucose and galactose were oxidized by resting cells. Oxygen consumption with glucose as the substrate was 18% of the theoretical amount required for complete oxidation, whereas with galactose, it was 83% of theoretical. Galactose-grown cells or cells grown in the absence of carbohydrates also oxidized pyruvate and acetate; the oxidation of these acids by glucose-grown cells was negligible. These data are consistent with either of the following hypotheses: glucose, or one of its metabolites, interferes with the metabolism of acetate, or glucose and galactose are metabolized by different pathways.
Fine structure of Arthrobacter crystallopoietes during long-term starvation of rod and spherical stage cells
Authors: Boylen Charles W. , Pate Jack L.
Published: February 2010

Actively growing spherical and rod-shaped cells of Arthrobacter crystallopoietes were subjected to total starvation in buffer for 8 weeks. At intervals, thin sections of cells were prepared and examined by electron microscopy. Starving cells underwent no morphological changes that would account for their unusual survival capabilities. Cell size and shape remained unaltered. There was no thickening of the cell wall and no development of structures similar to those observed in spores or cysts. As the length of starvation increased, the following changes were observed; glycogen deposits disappeared, the number of ribosome particles decreased, the number of vesicular membranes increased within the cell, and the nucleoplasm expanded in volume to fill the emptying cytoplasm.
A replicative form of the DNA of minute virus of mice
Authors: Dobson Phyllis R. , Helleiner C. W.
Published: February 2010

The growth of minute virus of mice (MVM) in L cells was followed by plaque assay of both cell-associated and free virus at intervals up to 36 h after infection. The major production of progeny virus occurred after incubation for 27 h and most of the virus remained cell-associated. L cells infected with MVM were pulse-labeled with 3H-thymidine for 6 h preceding induction of lysis with sodium dodecylsulfate. Two new species of DNA remained in the supernatant fractions from lysates after selective precipitation by 1 M NaCl of cellular DNA. These first appeared 17 h after infection. On the basis of sedimentation rates and response to heating and to treatment with alkali, one of these species is a hydrogen-bonded duplex molecule, which on denaturation hybridized with the single-stranded DNA of MVM virions.
Ultrastructure of two species of oil-degrading marine bacteria
Authors: Atlas R. M. , Heintz C. E.
Published: February 2010

Two species of marine bacteria with the ability to degrade crude oil were compared ultrastructurally after growing in the presence and absence of oil. Large electron-dense inclusions, which were located predominantly at the cell terminus, characterized species of Flavobacterium and Brevibacterium when growing on oil. Cells of Flavobacterium sp. had smaller inclusions when grown on marine agar, while inclusion bodies were not found in Brevibacterium sp. grown on marine agar. Sudan black B staining indicated the inclusions are stored lipids.
Growth of microorganisms in two-dimensional steady-state diffusion gradients
Authors: Caldwell D. E. , Hirsch P.
Published: February 2010

A two-dimensional, steady-state diffusion system has been devised for growth of microorganisms in nutrient concentration gradients. Two reservoirs continually supply substrates, while unused substrates and waste products are washed into a third reservoir. Substrates are supplied in the form of a steady-state gradient within an agar sheet which contains the test organisms. Microbial populations can thus be exposed to all values and combinations of two test variables. The system was tested with Escherichia coli grown in glucose and bicarbonate gradients. Hyphomicrobium sp., Rhodomicrobium vannielii, and Thiopedia sp. in a mixed population were segregated by use of a gradient system of methylamine and sodium sulfide. Exposure of natural aquatic populations to a gradient of pond mud and acetate resulted in differential growth of Bacillus sp. and rod-shaped bacteria with terminal endospores. Thus the potential value of gradients in predicting the response of natural microbial communities to nutrients or toxicants and in enriching for specific organisms has been demonstrated qualitatively.
Studies on the cell wall of Spirillum serpens. II. Chemical characterization of the outer structured layer
Authors: Buckmire Francis L. A. , Murray Robert G. E.
Published: February 2010

The outer cell-wall layer of Spirillum serpens VHA, composed of a hexagonal array of macromolecules, was dissociated from 'cleaned' cell-wall fragments with 1.5 M guanidine hydrochloride, pH 7.0. The soluble material contained 98% protein, 2% carbohydrate, and no ethanolamine, phosphate, RNA, or DNA. Evidence for the homogeneity of the isolated cell-wall protein was obtained by sedimentation velocity, polyacrylamide disc gel electrophoresis, molecular sieve chromatography on Sephadex G-200, and sucrose density gradients. The protein was acidic and had a minimum molecular weight of about 48 000 daltons calculated from the amino acid analysis. A molecular weight of between 125 000 and 150 000 daltons was obtained for the protein by polyacrylamide disc-gel electrophoresis, sucrose density gradients, and molecular sieve chromatography. The sedimentation rate of the protein was considerably less in 1.5 M guanidine hydrochloride, pH 7.0, than in its absence although the protein remained homogenous under both conditions. Self-assembly of the purified protein into its original hexagonal layer on a template of wall fragments from which the protein had been removed previously was obtained when the mixture was incubated in the presence, but not in the absence of Ca2+. It seems likely that the particles (hexagons) seen on the surface of the cell are an assembly of trimers.
Hyphomycetes utilizing natural gas
Authors: Davies J. S. , Wellman A. M. , Zajic J. E.
Published: February 2010

Twelve cultures of Hyphomycetes capable of growth upon the ethane component of natural gas were isolated from raw sewage by a continuous enrichment technique. In addition, all isolates also grew on propane and n-butane but not methane. These cultures are described and their taxonomic position discussed. Four were tentatively placed in Graphium; three were identified as Phialophora jeanselmei (Langeron) Emmons; the remaining five are similar to Acremonium sensu Gams.
Chromosomal mapping of Brucella abortus, strain 19
Authors: Altenbern Robert A.
Published: February 2010

A genomic map of Brucella abortus, strain 19, containing the relative locations of 19 genes has been derived by use of marker frequency analysis. Under the conditions used, the chromosomal replication time was approximately 60 min and the mass duplication time was 216 min.
Role of vacuoles and vesicles in extracellular enzyme secretion from yeast
Authors: Holley R. A. , Kidby D. K.
Published: February 2010

Preliminary evidence has been obtained which suggests that the intracellular invertase of Saccharomyces cerevisiae may not be localized in the vacuole per se. Alkaline phosphatase, an intracellular enzyme, and acid protease, a typically lysosomal enzyme, both showed high specific activity in the vacuole fraction prepared by equilibrium centrifugation of lysed sphaeroplasts in Ficoll gradients. Invertase activity has been found to be associated with vacuoles only when glucose-repressed cells are derepressed. Cells derepressed for invertase biosynthesis contained a population of vesicles which were virtually absent from the repressed cells. Evidence is presented which strongly suggests that these vesicles rather than the vacuoles are the vehicle by which invertase is secreted from the cell.
Studies on cell fusion and the rescue of SV40 from cell cultures of successive generations of Cl2TSV5- and RHaT-produced hamster tumors
Authors: Menezes Jose , Perry Edgar
Published: February 2010

Five successive generations of tumors have been produced in inbred Syrian hamsters after initial inoculation of SV40-transformed Cl2TSV5 and RHaT cell lines.SV40 could be rescued by cell fusion with inactivated Sendai virus from cell cultures of all five tumor generations. T-antigen was detected in all cultures by fluorescent antibody staining.An increased capacity for fusion of SV40-transformed cells after successive passages in hamsters has been observed.In addition to monkey kidney cells, bovine and lapine kidney cells have been successfully used for SV40 rescue by cell fusion.
Alkaline phosphatases of Neurospora crassa. Part III. Effects of pH and mechanism of action
Authors: Davis F. W. J. , Lees Howard
Published: February 2010

The effects of pH on the activity of a highly purified constitutive alkaline phosphatase from Neurospora crassa were studied. The pH optimum for the reaction was a linear function of the logarithm of the substrate concentration, as is typical for alkaline phosphatases. Other pH effects were complex and Vmax or pKm versus pH plots differed for the two substrates used and from similar plots prepared with the repressible enzyme from this or other sources. The Km for p-nitrophenyl phosphate increased 200-fold over the pH range 7.0–8.7. Substrate inhibition was more pronounced at low than high pH. Lineweaver-Burk plots were non-linear at high substrate concentration but linear at low substrate concentration. Substrate inhibition by glucose 6-phosphate was not observed.The data are consistent with the hypothesis that hydroxyl ion is a second substrate for the enzyme and is an activator at high and an inhibitor at low p-nitrophenyl phosphate and glucose 6-phosphate concentrations. A Bi-Bi mechanism with random substrate addition, dead-end substrate, and product inhibition, having ordered release of products is discussed and is consistent with kinetic and pH studies. A two-site model for the active center of the enzyme is presented to account for alternate product inhibition data.
L'identification du virus de l'influenza à l'aide de l'immunoperoxydase
Authors: Dobardzic R. , Boudreault A. , Pavilanis V.
Published: February 2010

The specific antibodies anti-influenza virus A2/Aichi/68 were combined immunologically with the virus purified by zonal centrifugation, then dissociated by lowering the pH and conjugated with horseradish peroxidase using glutaraldehyde as the coupling agent. With so labeled antibodies it was possible to detect the viral antigen in infected chick embryo kidney cells with the light microscope. This work suggests that the immunoperoxidase technique could be useful for early rhinocytologic diagnosis of influenza virus infections.
Associated organelles in the blue-green alga, Anacystis nidulans
Authors: Dierksheide William C. , Pfister Robert M.
Published: February 2010

An examination of the fine structure of Anacystis nidulans, a blue-green alga, has revealed an association between the electron-dense polyphosphate granules and the cyanophycin granules sometimes referred to as lamellasomes. It is possible that the deposition of phosphate occurred within the cyanophycin granule.
Abundant growth and sporulation of Bacillus sphaericus NCA Hoop 1-A-2 in a chemically defined medium
Authors: Chan E. C. S. , Rutter P. J. , Wills A.
Published: February 2010

A chemically defined medium was formulated for the vegetative growth of Bacillus sphaericus NCA Hoop 1-A-2. Growth was enhanced by supplementing with synthetic or naturally occurring chelators. In the presence of EDTA, in addition to increased growth, the strain sporulated to varying degrees.
In vivo synthesis of sulfur containing amino acids in Candida albicans
Authors: Mardon David N.
Published: February 2010

Growth in a supplemented minimal culture medium and chlamydospore formation in supplemented corn meal agar were the criteria used to evaluate in vivo biosynthesis of sulfur containing amino acids in auxotrophs of Candida albicans. Supplementation with L-cystathionine, L-homocysteine, L-methionine, S-adenosyl-L-methionine, or S-adenosyl-L-homocysteine resulted in growth in the minimal medium and both growth and chlamydospore formation in corn meal agar. One auxotroph (CYS) gave comparable results when inoculated into media supplemented with L-cysteine, responded minimally when O-acetyl-L-serine and sulfide comprised a dual supplement, and failed to grow or form chlamydospores when sulfide or O-acetyl-L-serine was used as a single supplement, suggesting that this organism may possess a deficiency in the synthesis or activity or cysteine synthetase. Another auxotroph (OAHS) did not grow or produce chlamydospores when O-acetyl-L-serine was added to the media in combination with sulfide, or when either L-cysteine, O-acetyl-L-serine, sulfide, or L-homoserine was used as a single supplement, but did respond to media supplemented with O-acetyl-L-homoserine indicating a deficiency in homoserine-O-transacetylase in this microorganism. Auxotroph OAHS grew and formed chlamydospores as well in media containing only supplemental O-acetyl-L-homoserine as it did when O-acetyl-L-homoserine was used in combination with sulfide S-methyl-L-cysteine or thiomethyladenosine, while (CYS) neither grew nor produced chlamydospores in any of these supplemented media. These results lend support for the hypothesis that cystathionine is an important intermediate in methionine biosynthesis in C. albicans. The positive results obtained when the auxotrophs were inoculated into media supplemented with S-adenosyl-L-homocysteine or S-adenosyl-L-methionine may reflect an alternate route for methionine biosynthesis which functions conditionally in this microorganism. The potential significance for endogenous formation of sulfur containing amino acids from S-adenosylmethionine is therefore considered.
Soil bacteriostasis limitation in growth of soil and rhizosphere bacteria
Authors: Brown Margaret E.
Published: February 2010

Sensitivity of soil bacteria to bacteriostasis was assessed by an agar disk method. Most bacteria isolated from wheat rhizosphere (98%) were sensitive and those not stimulated by roots were not sensitive. Bacteriostasis was always overcome by the addition of wheat root exudates to the disks and sometimes by the addition of glucose or mineral salts. Bacteriostasis was active in all six soils studied but less so in those with acid pH. Bacteriostasis was removed partially by air-drying the soil and totally by sterilizing. Filtrates of soil extracts retained some activity unless completely sterile.
Fluorescent antibody as a method for the detection of fecal pollution: Escherichia coli as indicator organisms
Authors: Abshire R. L. , Guthrie R. K.
Published: February 2010

A fluorescent antibody method for detection of fecal coliform pollution in water is reported. Detection of Escherichia coli of fecal origin by this method was compared to IMVIC typing and to detection by the E C Broth method. Reliability of this method was tested by reaction of specific E. coli antisera with heterologous bacterial species and with isolates from polluted waste water and unpolluted water and soil sources. This method was found to offer the advantage of greater rapidity over conventional water quality tests, without loss of reliability.
Nuclei in the somatic hyphae of Trichophyton mentagrophytes
Authors: Bakerspigel A.
Published: February 2010

There are four chromosomes present in the somatic nuclei of Trichophyton mentagrophytes. Initially, these chromosomes are ring-shaped but as division proceeds they unfurl becoming rod-like. The spindle apparatus appears to be strand-like and beaded. At mid-division the chromosomes lie in two rows parallel to each other and on either side of the spindle. Each row contains four chromosomes which appear to be attached to the spindle at regions along its length. At the end of division each sister nucleus contains a complement of four chromosomes. Movement of sister nuclei at the end of division appears to be unipolar. The single nucleolus in T. mentagrophytes does not disappear from view during division or immediately after separation of sister nuclei. As a result this nucleolus has been designated as an "undivided persistent nucleolus."
Immunochemical studies on the lipopolysaccharides of Bordetella pertussis
Authors: Aprile M. A. , Wardlaw A. C.
Published: February 2010

Lipopolysaccharide (LPS) was extracted from three Phase I strains (18334, 1494, and 134) and one Phase IV strain (11615) of B. pertussis. LPS was also obtained from ATCC 190 and NCTC 8632 which are listed as B. pertussis Phase IV but proved to be Lophomonas sp. and Brucella melitensis type 1. Chromatographic studies and chemical analysis revealed that all four B. pertussis LPS contained hexosamine, heptose, and hexose.The antigenic structure of the extracted LPS was studied by the techniques of passive immune lysis, lysis inhibition, and Ouchterlony immunodiffusion using homologous and heterologous rabbit antisera. The four B. pertussis LPS possessed at least six antigenic determinants. Four of these, designated A, C, E, and F, were found only in LPS of strains 18334 and 1494 (Phase I). Determinant D was found only in strain 134 (Phase I) and strain 11615 (Phase IV). All four strains of B. pertussis shared a sixth determinant, B. Antigen C was shared with the LPS of Lophomonas sp. (ATCC 190) and antigen F with the LPS of Brucella melitensis (NCTC 8632).There was no close correlation between the pattern of antigenic determinants on the LPS and other properties of B. pertussis, such as growth characteristics and possession of the protective antigen and the histamine-sensitizing factor.
Chemotaxonomic fatty acid fingerprints of bacteria grown with, and without, aeration
Authors: Drucker D. B. , Owen I.
Published: February 2010

Fatty acid fingerprints were obtained for Bacillus megaterium, Corynebacterium xerosis, Klebsiella aerogenes, Neisseria catarrhalis, Serratia marcescens, Staphylococcus saprophyticus, and Streptococcus faecalis. The test organisms were grown with, and without, aeration. Freeze-dried cells were methylated and the fatty acid methyl esters examined gas-chromatographically. Aerated cultures showed greater variation in fingerprints than non-aerated cultures and distinction between the species tested was readily possible.
Scanning electron microscopy of morphological alterations in Proteus mirabilis induced by cephalosporins and semisynthetic penicillins
Authors: Perkins Robert L. , Miller Marcia A.
Published: February 2010

Experiments, using the scanning-beam electron microscope, were conducted to compare the morphologic lesions induced in a strain of Proteus mirabilis by two semisynthetic penicillins, ampicillin and carbenicillin, and two cephalosporins, cephalothin and cephaloridine. The observations demonstrated that the semisynthetic penicillins and cephalosporins did not induce the same sequence of structural alterations. In the presence of cephalothin or cephaloridine, mid-cell spherical defects were induced which rapidly progressed to large bulbous enlargements at low concentrations (2 and 20 μg/ml) but only spheroplast-like forms were observed at high concentrations (200 and 2000 μg/ml). Ampicillin and carbenicillin caused similar alterations in morphology except that marked cell elongation without division occurred with 2 and 20 μg/ml. These variations may reflect subtle differences in sites, rates, sensitivity, or mechanisms of action between these two groups of cell-wall inhibiting antibiotics.
The protective mechanism of nitrogenous organic substances against NaCl-induced hypertonic stress of a halotolerant pseudomonad
Authors: Keller Paulina , Aloni Chamutal , Henis Y.
Published: February 2010

A halotolerant pseudomonad was isolated from a hydrohalomorphic soil. It required yeast extract and casitone for growth only when transferred from 1% to 10% NaCl-containing agar medium. These supplements prevented loss of viability occurring upon transfer from low to high NaCl-containing media, shortened the prolonged lag period, and shortened generation time. Loss of viability also occurred upon transfer of cells grown on 1% NaCl to solutions of sucrose, KCl, MgCl2, KNO3, or NaNO3 isomolar with 10% NaCl. Cells grown on 10% NaCl did not lose viability on such transfer.In cells transferred from 1% to 10% NaCl, a decrease in amino acids, a partial inhibition of the uptake of 14C-labeled L-proline, and a total blocking of its incorporation into the TCA-insoluble cell fraction was observed. Neither the addition of chloramphenicol at concentration which blocked incorporation of 80% of 14C-labeled proline into the TCA-insoluble cell fraction, nor the maintaining of the cells at 5 °C during transfer from low to high salt containing media eliminated the protective effect of yeast extract plus casitone. Turbidity changes which accompany hypertonic stress were not affected by the protective supplements. It is concluded that the protection is not due to synthesis of macromolecules or to metabolic activity.
The effect of inorganic phosphate on the biosynthesis of vancomycin
Authors: Mertz Frederick P. , Doolin Lawrence E.
Published: February 2010

The quantity of some of the molecular components of Streptomyces orientalis was markedly altered during the biosynthesis of vancomycin. The addition of elevated levels of inorganic phosphate caused changes in the amount of total carbohydrates, nitrogen, phosphate, DNA, RNA, and alkaline phosphatase in the cell during the fermentation. An excess amount of this ion also caused a decrease in the quantity of vancomycin synthesized as well as a lag in the time when synthesis was initiated. The possibility of a correlation between the biosynthesis of alkaline phosphatase and vancomycin is discussed.
Ultrastructure and characterization of an asporogenic mutant of Clostridium botulinum type E
Authors: Hawirko R. Z. , Chung K. L. , Emeruwa A. C. , Magnusson A. J. C.
Published: February 2010

The asporogenic mutant, RSpoIIIa, showed septum formation and a nearly completed forespore about 4 h after onset of sporulation. The cells show defects at a few sites of the forespore membrane, an absence of 'germ cell wall,' and within 8 h lysis of the cytoplasm occurred indicating that the mutant was blocked at stage III. Some aberrant envelopes were seen later. Lysis of the asporogenic mutant was inhibited for up to 36 h by the addition of 2.4% glucose or sucrose to the medium and 80% of the cells showed septum formation. A comparison of the phenotypic characteristics of the asporogenic RSpoIIIa and the sporogenic MSp+ mutants, as well as the wild type, showed the same ultrastructural changes during the development of the forespore with the accumulation of intracellular iodophilic granules. In addition, the mutants showed specific immunofluorescence and precipitin lines of identity with antisera against the wild-type strain, but unlike the toxigenic wild type, the mutants were nontoxigenic by mouse pathogenicity tests.
Rapid extraction and physical detection of polyoma virus
Authors: Thorne H. V. , Wardle A. F.
Published: February 2010

A method for extraction and purification of polyoma virus from mouse embryo cells in tissue culture is described. Monolayer cultures are first solubilized with Triton-X-100 (20% w/v), then treated with RNase, DNase, and trypsin before equilibrium centrifugation in CsCl and collection of the virus band. The method is shown to be advantageous for the analysis of radioactive virus production from small numbers of cells.
Ultrastructure of Staphylococcus epidermidis after freeze-etching and thin sectioning
Authors: Gilchrist James E. , DeVoe Irving W.
Published: February 2010

A considerable quantity of information is now available on the ultrastructure of Staphylococcus (1, 2, 4, 7, 8, 10, 11, 12). Cell walls of these organisms in thin sections have been shown to consist of three layers: a dense outer layer, a rather electron translucent middle layer, and a very dense layer next to the cytoplasmic membrane (2, 7, 11, 12). Bulger and Bulger (2) have pointed out the presence of circumferential substructure in the middle layer of the wall in a strain of Staphylococcus aureus isolated as the causative agent in fatal pneumonia.Numerous mesosomes of both the vesicular and laminar types are evident in thin sections of staphylococci from several studies (1, 4, 7, 11). Moreover, single vesicular structures that appear to be invaginations of the trilaminar cytoplasmic membrane have been pointed out by Suganuma (11) and Beaton (1).
A satisfactory medium and technique for the mass cultivation of Sphaerophorus necrophorus
Authors: Garcia M. M. , McKay K. A.
Published: February 2010

A modified casitone (MC) medium was used successfully in the cultivation of the pathogenic non-sporing anaerobe, Sphaerophorus necrophorus. The medium is suitable for various physiological, biochemical, and immunological assays of the test organism and obviates the need for frequent passage to susceptible animal hosts. When cultured under a 5% CO2–95% N2 atmosphere at 37 °C, the logarithmic phase of growth occurred at 18–24 h postinoculation. A detailed description of an inexpensive apparatus and the technique for the large-scale production of S. necrophorus is included.
Inhibition of polyoma virus development in mouse–hamster heterokaryons
Authors: Babiuk Lorne A. , Hudson James B.
Published: February 2010

Mouse cells which normally permitted polyoma virus development, and hamster cells which were non-permissive (BHK-21 and polyoma virus-transformed hamster cells), were subjected to cell-fusion techniques, and the resultant cultures were examined for the capacity of heterokaryons to yield polyoma viral capsid protein. Little or no capsid protein was synthesized in the heterokaryons, although individual mouse cells and mouse homokaryons gave normal yields. Furthermore, the hamster cell inhibitory effect manifested itself even when the mouse cells had been infected with the virus before cell fusion.
Enzymes of glucose catabolism in cell-free extracts of non-fermentative marine eubacteria
Authors: Baumann Linda , Baumann Paul
Published: February 2010

Cell-free extracts of 12 species and groups of gram-negative, non-fermentative, marine eubacteria had enzyme activities characteristic of the Entner–Doudoroff but not the Embden–Meyerhof pathway.
Effect of supplementary aeration on the growth of Thiobacillus thiooxidans in shaken cultures
Authors: Feig Sol
Published: February 2010

The growth rate of shaken cultures of the strict autotroph, Thiobacillus thiooxidans, usually very slow, has been increased about threefold by increasing the level of aeration. The cell yield has also been improved somewhat by this procedure. CO2 enriched air does not enhance growth further.
The fine structure of Sphaerotilus nutans
Authors: Hoeniger Judith F. M. , Tauschel H.-D. , Stokes J. L.
Published: February 2010

Sphaerotilus natans developed sheathed filaments in stationary liquid cultures and motile swarm cells in shaken ones. Electron microscopy of negatively stained preparations and thin sections showed that the sheath consists of fibrils. When the filaments were grown in broth with glucose added, the sheath was much thicker and the cells were packed with granules of poly-β-hydroxybutyrate.Swarm cells possess a subpolar tuft of 10 to 30 flagella and a polar organelle which is usually inserted in a lateral position and believed to be ribbon-shaped. The polar organelle consists of an inner layer joined by spokes to an accentuated plasma membrane. The flagellar hook terminates in a basal disk, consisting of two rings, which is connected by a central rod to a second basal disk.
Lysosomes and the "toxicity" of Rickettsiales. IV. Ultrastructural studies of macrophages infected with a cytopathic L cell-grown C. psittaci 6BC strain
Authors: Kordová Nonna , Hoogstraten Jan , Wilt John C.
Published: February 2010

Mouse macrophages in vitro inoculated with a low dose of a cytopathic L cell-grown C. psittaci 6BC strain were harvested at times when a delayed cytopathic effect (CPE) was observed by light microscopy and when a cytochemical test for acid phosphatase revealed lysosomal enzyme release. An array of different lysosomal types was revealed by ultrastructural studies such as digestive vesicles with single or double outer membranes and whorls of membranes, dense residual bodies, aggregated and single scattered ferritin-like granules, and fragments of membranes. Enlargement of cysternae of endoplasmic reticulum, disintegration of cytoplasmic organelles, and thinning of ground cytoplasm were also observed. Cytoplasmic degeneration has been observed both within membrane-limited structures and in wider areas not limited by recognizable membranes.A high concentration of the agent resulted in an early toxic effect; this was accompanied by a rapid vacuolization of the cytoplasm of the macrophages which showed a poorly developed ultrastructure, and absence of mitochondria and cytoplasmic organelles. Cytochemical tests indicated that these alterations correlated with release of lysosomal acid phosphatase and disintegration of neutral red stained granules. Ultrastructural studies support the view that disintegration of lysosomes may be considered an important contributory factor in the pathology of chlamydial infection.
Metabolism of glycolic acid by Azotobacter chroococcum PRL H62
Authors: Kurz W. G. W. , LaRue T. A. G.
Published: February 2010

When Azotobacter chroococcum grows on glycolic acid as sole C source, it cannot utilize N2 and must be provided with reduced nitrogen. Glycolic acid is metabolized via Kornberg's dicarboxylic acid cycle. The TCA cycle enzymes are low in activity, and isocitric dehydrogenase is absent. It is likely that isocitric dehydrogenase is the source of reductant for nitrogen fixation by Azotobacter nitrogenase.
The relationship between the chemical structure of s-triazines and fungitoxicity to Sclerotium rolfsii
Authors: Ercegovich C. D. , Chrzanowski R. L. , Cole H. , Herendeen N. , Witkonton S.
Published: February 2010

Thirty eight substituted s-triazine and three dialkyl biguanide analogs were tested for their effects on mycelial growth and the formation of sclerotia by Sclerotium rolfsii. None of the chemicals were fungicidal to the organism at a test concentration of 100 μg/ml in potato dextrose agar. One of the chemicals, ipazine, was highly fungistatic, and 11 others demonstrated a significant but lower degree of activity against mycelial growth. The formation of sclerotia was completely inhibited in the presence of only one s-triazine, 2-amino-4-chloro-6-n-propylamino-s-triazine. Eight other s-triazines were as active as atrazine, the standard test chemical, in inhibiting the formation of sclerotia, and 10 more of the s-triazines were significantly effective but at a lower level of activity than atrazine. N1,N5-bis(ethyl)biguanide was the only chemical which caused a significant increase in the number of sclerotia formed. No absolute correlation was observed between biological activity and chemical structure although in certain instances there was an apparent correlation between toxicity and the overall electron withdrawing character of the non-alkylamino substituent on the s-triazine ring, or to the steric effects caused by the configuration of the alkylamino substituents. Only those chemicals which were highly active as herbicides were significantly effective in inhibiting mycelial growth and sclerotia formation; however, not all of the herbicidally active compounds were effective in this regard.