bluuebunny/crossref_metadata_2025 huggingface dataset:
Factors affecting the relative ratio of fatty acids in Bacillus cereus
Authors: Kaneda Toshi
Published: February 2010

Factors affecting relative proportions of long-chain fatty acids produced by the growing cells of Bacillus cereus have been studied. The organism produces nine branched (i-C12, i-C13, i-C14, i-C15, i-C16, i-C17, a-C13, a-C15, and a-C17), two normal (n-C14 and n-C16), and four monounsaturated (i-C161−, i-C17−1, a-C171−, and n-C161−), in addition to some minor fatty acids. On the basis of biosynthetic relationships these are grouped into four series: anteiso odd-numbered, iso odd-numbered, iso even-numbered, and normal even-numbered. The proportion of the normal series of fatty acids is generally not changed by varying growth conditions. The proportions of the three series of branched-chain fatty acids, however, are greatly affected depending upon growth phase and culture medium used. Younger cells tend to produce the four series in a closer ratio (1.5/1.8/0.8/1.0), whereas older cells produce four series in a wider ratio (1/2.2/0.8/1.0).The precursors of the terminal portions of branched-chain fatty acids, L-leucine, L-isoleucine, L-valine, and the related substrates, affected greatly the ratio of the three series of branched-chain fatty acids. Apparently the synthesis of iso odd-numbered acids is more tightly controlled than the synthesis of the two other series of fatty acids. Data suggest that this regulation is very likely to be due to the substrate specificity of the enzyme(s) involved in the fatty acid synthesis, rather than the relative availability of the precursors.
The phospholipid composition of Rhizobium japonicum
Authors: Bunn C. R. , Elkan G. H.
Published: February 2010

The phospholipids of Rhizobium japonicum were measured quantitatively, and the major phospholipids were shown to be phosphatidylserine, phosphatidylcholine, phosphatidylethanolamine, and cardiolipin. High levels of phosphatidylethanolamine and phosphatidylcholine were found. Such large amounts of phosphatidylcholine have been reported previously in the pseudomonads, and smaller amounts have been found in the genus Agrobacterium of the family Rhizobiaceae. The phospholipid composition of R. japonicum suggests a taxonomic relationship with the pseudomonads.
Hydroxyl apatite column chromatography of enterotoxin B
Authors: Chang P-C. , Dickie N. , Thatcher F. S.
Published: February 2010

Purified enterotoxin B was resolved into three components by hydroxyl apatite column chromatography. Only one of these components was toxic, but all three appeared to be serologically identical.
Presence of sacs enveloping the liquid droplets on developing sclerotia of Sclerotinia sclerotiorum (Lib.) DeBary
Authors: Colotelo N. , Sumner J. L. , Voegelin W. S.
Published: February 2010

Liquid droplets commonly observed on developing sclerotia of Sclerotinia sclerotiorum were found to be enveloped by small sacs. These sacs were present at all stages of sclerotia development when the fungus was cultured on various media and at various temperatures.
The effect of quaternary ammonium derivatives of bile acids on the rate of swelling of Pseudomonas aeruginosa in solutions of sodium and potassium salts
Authors: Bernheim Frederick , Lack Leon
Published: February 2010

Quaternary ammonium derivatives of bile acids increase the rate of swelling of washed cells of Pseudomonas aeruginosa incubated in solutions of potassium phosphate and to a lesser extent in solutions of sodium phosphate. The enhanced swelling is proportional to the concentration of the compounds in potassium but not in sodium solutions. The reason for this is that sodium but not potassium can displace the compounds from their attachment to the cell site(s) and the interaction is mixed competitive noncompetitive. Both cations, however, when added to cells before the compounds inhibit their effect. Formaldehyde-treated cells behave essentially in the same way as normal cells, which indicates that the compounds are not inhibiting metabolic pumps but are facilitating diffusion of the ions. As the steroid portion of the molecule becomes less lipophilic by the introduction of hydroxyl groups their activity decreases.
Aureobasidium pullulans as a source of sucrase
Authors: Reese Elwyn T. , Maguire Anne
Published: February 2010

The fungus A. pullulans (= Pullularia pullulans) produces exceptionally large amounts of extracellular sucrase when grown on sucrose monopalmitate, in the presence of Tween 80, and with limited shaking. Under optimum conditions, the culture filtrates contained as much sucrase as commercially available concentrates. The specific activity of the A. pullulans enzyme, after acetone precipitation, was as high as that of commercial preparations.
Ecological studies on yeasts in the St. Lawrence River
Authors: Simard R. E. , Blackwood A. C.
Published: February 2010

The total numbers of yeasts, bacteria, and coliforms found at five stations in the St. Lawrence River, sampled during a 5-month period in the summer of 1968, were compared to temperature, depth, biological oxygen demand (BOD), dissolved oxygen (DO), and salinity. Averaged data indicate some relationships exist among the biological and physical parameters but examination of the data for the individual samples do not lead to the same conclusions. However, the large increase in numbers of Rhodotorula glutinis (the dominant species of the 'pink yeasts') was found to follow the decrease in bacterial numbers, both total count and coliforms, after the introduction of sewage pollution. The metabolic characteristics of these 'pink yeasts,' allowing them to show such rapid increases in numbers, are not known.
The morphology of induced wall-defective variants of Streptococcus faecalis as studied by light and electron microscopy
Authors: Marraro R. V. , Pfister R. M. , Rheins M. S. , Kapetanovic I.
Published: February 2010

Study by light microscopy of induced wall-defective variants of Streptococcus faecalis was undertaken to examine the sequential development of these forms during a 36-day period. Particularly noted were the early cell wall deficient forms observed at 36 h which appear as "cartwheels." Evolution of these forms through the various stages of the granular-appearing colonies to the classical "fried egg" morphology is described. A similar developmental pattern was observed with both a prototype of the test organism as well as with a fresh isolate from the genitourinary tract of a patient.Colonies of induced wall-defective variants of S. faecalis grown on an induction medium were examined in the electron microscope by use of the technique of ultrathin sectioning. This study was undertaken to examine, at the cellular level, the colonial morphology of these variants and to describe differences existing in specified areas of the colony. Longitudinal thin sections of the induced wall-defective colonies were prepared from three levels of the colonies as they related to the medium surface: supraagar surface; subagar surface; and deep subagar. Examination of the thin sections offers evidence that the bacterial population in a single colony is morphologically heterogeneous.
Germination and outgrowth of Bacillus thuringiensis and Bacillus alvei spores viewed by scanning electron and phase-contrast microscopy
Authors: St. Julian Grant , Bulla Jr. Lee A. , Hesseltine Clifford W.
Published: February 2010

Germination and outgrowth of Bacillus thuringiensis and Bacillus alvei spores were observed by scanning electron (SEM) and phase-contrast microscopy. Germination, seen in phase-contrast as the loss of retractility of the spore, appears in SEM as a partial collapse of the spore. This collapse parallels the long axis of B. thuringiensis and is perpendicular to that of B. alvei. Outgrowth is initiated when the spore begins to swell. During swelling, the outgrowing spore appears to collapse in SEM and, for B. thuringiensis, becomes gnarled. It then begins to elongate and during the elongation time the parasporal body of B. thuringiensis loses its refractility and swells. B. alvei has no parasporal body. As the cell pushes its way out of the sporangium, the phase-dark parasporal body loses definitive shape; the emerging cell may elaborate an enveloping structure seen only in SEM. This cell then divides into two vegetative cells that also are surrounded by a similar structure. Such an enveloping structure is not seen with B. alvei.
Effects of radiation pasteurization on Salmonella. III. Radiation lethality and the frequency of mutation to antibiotic resistance
Authors: Previte Joseph J. , Chang Y. , El-Bisi H. M.
Published: February 2010

The radiation resistance (D, in megarads) of six strains of Salmonella irradiated at 4C in brain heart infusion suspension ranged from 0.042 for S. enteritidis to 0.084 for S. thompson. The resistance values were 0.048 for S. typhimurium, strain SR-11, 0.060 for S. typhimurium, strain RIA, and S. newport, and 0.078 for S. heidelberg. The mutation frequency to tetracycline resistance of S. typhimurium, strain SR-11, increased between 0 and 0.05 Mrad and declined thereafter with increasing radiation dose. After 0.5-Mrad exposure, the mutation frequency was essentially the same as in control populations. The mutation frequency to streptomycin resistance of S. typhimurium, strain SR-11, decreased at doses greater than 0.05 Mrad and increased only slightly for the more radiation-resistant serotypes, S. typhimurium, strain RIA, S. thompson, and S. heidelberg. The average mutation frequency of the four Salmonella cultures tested was essentially unchanged (less than 1 log difference) between 0.05 and 0.5 Mrad, while the difference in reduction in viable numbers was 5 logs or greater. The evidence presented indicates that with the proper choice of processing parameters, the application of radiation pasteurization could drastically reduce the possibility of transmission of Salmonella by poultry and thereby decrease the public health hazards associated with this microorganism.
Differential induction of pectolytic enzymes of Fusarium roseum (Lk.) emend. Snyder and Hansen
Authors: Perley A. F. , Page O. T.
Published: February 2010

Pectolytic enzymes of Fusarium roseum were differentially induced at pH 3.5 and 6.5 in solutions of specific pectic substances. Endopolygalacturonase was induced in 0.02 M mucic acid and 1% polygalacturonic acid solutions at pH 6.5 and also in a 1% pectin solution at pH 3.5. Endopolymethylgalacturonase was induced in a 1% pectin solution at pH 6.5. In addition, pectinesterase and endopectin methyl-trans-eliminase were induced in 1% pectin solutions at pH 3.5 and 6.5, respectively.Inclusion of 0.005 M CaCl2 in reaction mixtures inhibited the degradation of polygalacturonic acid by mucic and polygalacturonic acid induced polygalacturonase. In contrast, the breakdown of pectin by the pectinesterase and polygalacturonase induced in 1% pectin solutions, pH 3.5, was stimulated.
Ultrastructure of the cell wall and the mechanism of cellular division of a Gram-variable coccus
Authors: Gilleland Jr. H. E. , Roth I. L. , Eagon R. G.
Published: February 2010

An ultrastructural study of a Gram-variable coccus was carried out. The cell wall of this microorganism was composed of an inner peptidoglycan layer, a middle electron-transparent compartment, and an undulating trilayered outer membrane. This microorganism also possessed numerous mesosomes which were simple bulb-like invaginations of the cytoplasmic membrane. The mechanism of cellular division involved the formation of a septum by the cytoplasmic membrane and the inner layer of the cell wall. Membranous structures were associated with the developing septum throughout the process. The outer membrane of the cell wall did not invaginate with the inner layer but reformed as the completed septum began to split. In isolated cell wall preparations, no 2-keto-3-deoxyoctonate or heptose could be detected. It is suggested that the Gram-variable cocci previously classified as micrococci may represent a group that is intermediate between true Gram-negative and Gram-positive bacteria.
Presence of two DNA populations in Mycoplasma laidlawii
Authors: Dugle David L. , Dugle Janet R.
Published: February 2010

The presence of a DNA population having a molecular weight of 38 ± 5 × 106 in addition to the cellular genome, 99 ± 5 × 107 daltons, in Mycoplasma laidlawii B is evidence for the existence of a satellite DNA or virus intrinsic to these cells.
Alternate methods of nutrient dosing in continuous phased culture
Authors: Dawson P. S. S. , Phillips K. L.
Published: February 2010

An alternative method for nutrient dosing in continuous phased culture is described. In this procedure the volumes of gas and culture remain unchanged in the system. This facilitates transfers of medium and effluent culture in the culture vessel and permits experimental manipulations additional to those obtained with the previously described method of dilution phasing. The two methods of dilution and displacement dosing are compared.
The development of lignitubers in roots after infection by Verticillium dahliae Kleb.
Authors: Griffiths D. A.
Published: February 2010

Hyphae of Verticillium dahliae Kleb. penetrated the roots of tomato and pea seedlings and induced the deposition of lignitubers between the host plasmalemma and cell wall. Lignitubers prevented further colonization by the fungus which underwent protoplasmic lysis within the lignituber. Evidence is also presented to suggest that lignituber formation results from the extrusion of vesicles by the host.
Effect of substrate on the lipids of the hydrocarbon-utilizing Mycobacterium vaccae
Authors: Vestal J. Robie , Perry J. J.
Published: February 2010

Cells of Mycobacterium vaccae strain JOB5 grown on ethane, propane, or n-butane contained about twice as much lipid as cells grown on acetate, isopropanol, or propionate. Propane-grown cells contained more neutral lipid (34.4%) than acetate-grown cells (19.4%) and there was a correspondingly greater percentage of phospholipid in acetate-grown cells. When cells grown on acetate were harvested and resuspended in a growth medium with propane as substrate, the synthesis of lipid preceded synthesis of nitrogenous components and cell multiplication. The lipid fraction that increased most by growth on propane was triglyceride. It is suggested that this lipid may play a role in the assimilation of the hydrophobic hydrocarbon substrate.
Effect of infection with R23 on DNA and RNA synthesis in Escherichia coli
Authors: Watanabe Hiroko , Watanabe Mamoru
Published: February 2010

Infection of Escherichia coli by R23 results in a marked inhibition of rRNA synthesis. Both 16 S and 23 S RNA are inhibited with maximal inhibition occurring at 30 min. Inhibition of 4 S RNA is not as profound. DNA synthesis is also inhibited after R23 infection although infected cells continue to divide for about one generation (45–60 min) after infection.
Studies of tolerance to organ antigens. The immune response to A/Jax strain mouse organs in normal and A/Jax strain mouse liver tolerant rabbits
Authors: Baines M. G. , Eidinger D.
Published: February 2010

Neonatal rabbits were injected with large amounts of pooled normal A/Jax strain mouse liver and serum to induce tolerance to the organ and species antigens present in this mixture. At 3 months of age, the "tolerant" and uninjected control rabbits were all challenged with either A/Jax strain heart and (or) liver or kidney and their responses were compared by precipitation, hemagglutination (HA), and indirect fluorescent antibody tests (IFab). The normal sera showed one to four precipitation arcs on two-dimensional immunodiffusion analysis against their respective organ antigens and those demonstrable on immunoelectrophoresis migrated predominantly in the β and γ globulin regions. Organ-specific antibodies reacting with the organ antigens of the immunizing species and heterologous species were easily quantified by HA titrations and localized by IFab tests. It was noted that antigens common to the tissues of the immunizing species were found principally in the supportive cell structures whereas organ-specific antigens were found in the cytoplasmic region of the immunizing tissue and in similar tissues of different species.Antisera derived from the "tolerant" rabbits immunized with heart and (or) liver showed virtually normal heart specific responses while the response to liver was significantly suppressed. The complete absence of the cross reaction to guinea pig liver in the "tolerant" sera was taken as evidence of the tolerance mediated suppression of the reactivity to some of the mouse liver antigenic determinants.
Serological cross-reactivity within the picornaviruses as studied by electron microscopy
Authors: Chaudhary R. K. , Kennedy D. A. , Westwood J. C. N.
Published: February 2010

A sensitive electron microscopic method has been developed to determine the antigenic relationship within the picornavirus group. Negatively stained mixtures of antigens (poliovirus type 1 and 3, echovirus type 9, and coxsackievirus type A9) and antibodies (poliovirus type 3 and echovirus type 9 antisera) were examined under the electron microscope. The results showed clumping of homologous and heterologous viruses with both antisera, which was considered as evidence of cross-reaction. The controls showed no clumping or attachment of antibody molecules. The significance of clumping was tested by treating adenovirus type 7 with the two test antisera.
The enhancement of X-ray-induced DNA degradation in Micrococcus radiodurans by phenethyl alcohol
Authors: Driedger A. A. , Grayston M. J.
Published: February 2010

The effects of phenethyl alcohol on DNA synthesis and X-ray-induced DNA excision–repair were studied in Micrococcus radiodurans. At 0.20% concentration, the drug selectively inhibited DNA synthesis. Higher concentrations and prolonged incubation promoted DNA breakdown.Irradiation and PEA together promoted increased DNA breakdown in a characteristic fashion depending upon the time at which it was added. This effect was lost after the cells had undergone one postirradiation division. PEA did not inhibit repair of X-ray-induced single strand breaks. At high doses the two agents no longer enhanced each other's action and this suggests that they acted on a common target. It is proposed that X-ray-induced DNA breakdown is at least partly due to damage of a non-DNA structure such as the cell membrane, since persistent breaks in the DNA are not required for X-ray-induced, PEA-potentiated DNA degradation.
Fine structure of ascospore development in the yeast Saccharomyces cerevisiae
Authors: Moens Peter B.
Published: February 2010

In the yeast Saccharomyces cerevisiae, ascospore development is initiated through the movement of nuclear material and cytoplasm into an envelope, or prospore wall. The prospore wall is first observed at the cytoplasmic side of the spindle plaque during the second meiotic division. When the 'prospores' attain their full size, the envelope closes and the ascospore becomes spherical. At this stage the central, electron-transparent, zone of the prospore wall becomes more prominent. Eventually the central zone expands into the mature cell wall. This description is based on observations of glutaraldehyde-fixed cells, and it differs in some details from reports based on KMnO4-fixed yeast cells.
Effects of glutamic acid on sporulation of Bacillus cereus and on spore properties
Authors: Kennedy R. S. , Malveaux F. J. , Cooney J. J.
Published: February 2010

The effects of glutamic acid on growth, sporulation, and properties of Bacillus cereus spores were studied using a glutamic acid – glucose – glycine – yeast extract medium (+GA +YE) and a medium in which five amino acids were substituted for yeast extract (+GA +AA). In the +GA +YE medium, glucose and glycine were used principally during vegetative growth but glutamic acid was used during growth and sporulation. Omission of glutamic acid from either medium (−GA +YE or −GA +AA) reduced the percentage of the final population which was heat resistant. The resistance of the spore populations decreased as the complexity of the medium decreased (+GA +YE > −GA +YE > +GA +AA > −GA +AA). All four media supported 90+% sporulation, but total cell yield decreased and the time required for growth and sporulation increased as the complexity of the medium decreased. The most heat-resistant populations contained the least DPA per spore and had the highest Ca:DPA ratio. Spores from glutamic acid deficient medium (−GA +YE) were less resistant to ultraviolet radiation (uv.) than spores from +GA +YE medium. Glutamic acid deficiency in either medium did not influence refractility, calcium content, phase brightness, or phenol sensitivity of spores produced. Growth and sporulation were followed and spore properties were examined from cultures initiated in −GA +YE medium and supplemented with glutamic acid at specific times during the cycle of growth and sporulation. Glutamic acid was not used for organic acid production during vegetative growth but contributed to poly-β-hydroxybutyrate production, and it was used for vegetative growth. Glutamic acid was required in the medium before or during septum development for acquisition of maximum uv. resistance, and was required in the medium before or during forespore and cortex formation to influence DPA content and heat resistance.
Lysis of zoopathogenic fungi by streptomycetes
Authors: Howard Dexter H. , Gupta Rishab K.
Published: February 2010

The cell walls of the yeast cell phases of Histoplasma capsulatum, Blastomyces dermatitidis, and Sporothrix schenckii were lysed by enzymes formed during the growth of Streptomyces spp. Mycelial elements of H. capsulatum were not lysed by the streptomycetes.
The isolation of Vibrio parahaemolyticus and related halophilic bacteria from Canadian Atlantic shellfish
Authors: Thomson W. K. , Trenholm Dixie A.
Published: February 2010

A survey of Canadian Atlantic shellfish was carried out to determine the presence of Vibrio parahaemolyticus. Twenty-eight strains, closely resembling authentic strains from Japan, were isolated from unfrozen specimens of shellfish obtained at local retail outlets. Six isolates were obtained from shellfish collected and frozen by the Inspection Branch, Department of Fisheries and Forestry.
Enteric bacterial metabolism of stream sediment eluates
Authors: Hendricks Charles W.
Published: February 2010

River bottom sediments, which were washed free of loosely associated chemical nutrients, were further eluted with phosphate buffer. Chemical analyses of the eluates indicated that 0.3 M buffer (pH 7.0) eluted hexose, protein, and ammonia nitrogen in concentrations 4–6 times that found in the free-flowing water. Respiration experiments showed that selected strains of Enterobacteriaceae, including pathogens, had the ability to metabolize these substrates. These studies indicate that bottom sediments can have a high adsorptive capacity and suggest that they can regulate basic nutrient concentration and eutrophication in situ.
Increased activity of soil microorganisms near sclerotia of Sclerotium rolfsii in soil
Authors: Gilbert R. G. , Linderman R. G.
Published: February 2010

Microbial activity of soil near sclerotia—"mycosphere" (MS)—increased markedly within 24 h after sclerotia of Sclerotium rolfsii were pressed into the soil, but no changes occurred in the microbial activity of soil not near the sclerotia—non-mycosphere (NMS). Increased microbial activity in the MS, called the "mycosphere effect," was attributed to increased bacterial activity, since numbers of fungi and actinomycetes remained relatively unchanged. The qualitative selection of specific bacteria in the MS by sclerotia was suggested by the increase in bacteria that were tolerant to streptomycin and oxgall bile salts in the plating medium. Exposure of the soil to volatile compounds from alfalfa hay before adding the sclerotia enhanced the rate of the microbial increase in the MS. The energy substrate for the increase in MS organisms was of sclerotial origin and not from culture nutrients adhering to the sclerotia. Addition of concentrated sclerotial leachate to soil, and exposure of soil to alfalfa volatiles also induced an increase in the MS organisms.Bacteria from the MS affected S. rolfsii in vitro more than did bacteria from the NMS. Most of the MS bacteria were inhibitory to S. rolfsii on Difco plate-count agar, had no effect on potato-dextrose agar, and were stimulatory on Czapek-Dox agar. These results suggest that the nutritional status in the MS, as determined by sclerotial exudation or external nutrients, may be of primary importance in determining whether MS organisms will inhibit, will stimulate, or will have no effect on the sclerotia of S. rolfsii.
Lysis of Bacillus subtilis, Escherichia coli, and Staphylococcus aureus by phenethyl alcohol
Authors: Zyskind J. Weaver , Pattee P. A.
Published: February 2010

Concentrations of phenethyl alcohol (PEA) slightly above the bacteriostatic concentration lysed actively growing cells of Bacillus subtilis, Staphylococcus aureus, and Escherichia coli. Cultures of these three organisms from the stationary phase were much less susceptible to the lytic action of PEA.
A biodegradability test for insecticides
Authors: Halvorson Harvest , Ishaque M. , Solomon J. , Grussendorf O. W.
Published: February 2010

A method is suggested for testing the biodegradability of insecticides using bacteria from a sewage lagoon. The proposal is based on results which showed that the biodegradable organophosphates Malathion, Parathion, and Diazinon were metabolized quickly by resting cell suspensions of lagoon bacteria while the persistent chlorinated hydrocarbons Heptachlor, Dieldrin, and DDT were metabolized poorly or not at all. Data also showed that oxygen was not an important regulator of catabolism for any of these insecticides. Heptachlor epoxide and DDD were the only metabolites identified. The advantages of the method are discussed.
Tremorgenic toxins from penicillia. II. A new tremorgenie toxin, tremortin B, from Penicillium palitans
Authors: Hou C. T. , Ciegler A. , Hesseltine C. W.
Published: February 2010

A new tremorgenic mycotoxin, tremortin B, was found in the solvent extract of Penicillium palitans mycelium. Tremortins A and B were purified by column chromatography on Florisil followed by Sephadex LH20, and recrystallized from several solvents. Tremortin B was determined to be C37H45NO5.The LD50 of A is 1.05 mg and B, 5.84 mg/kg mouse. A third potential tremorgen, tremortin C, has also been isolated and purified, but so far the yield is insufficient to determine its characteristics.
Mitosis in Penicillium chrysogenum and Penicillium notatum
Authors: Crackower Sydney , Bauer Heinz
Published: February 2010

Vegetative nuclear division was studied in Penicillium notatum and P. chrysogenum using light microscopy of stained preparations. The results obtained revealed mitoses in which duplicate sets of chromosomes were equitably divided into daughter genomes by successive division stages. From the resting stage consisting of a shell of granular chromatin, the dividing nucleus entered into a more densely staining stage containing chromosomes which appeared to be arranged in the formation of coiled cords. In the next stage of division the chromosomes became oriented into two parallel units and were then aligned in two's in a rectangular configuration. Division proceeded by movement of chromosomes to opposite poles. Mitosis included the development of a thin fiber which began as a deeply staining granule at one side of a spherical nucleolus. The granule divided into two components and then the thin fiber elongated between them.
Observations on budding cells of Torulopsis glabrata
Authors: Brown J. P. , Edwards Mercedes R.
Published: February 2010

The diminutive pathogenic yeast Torulopsis glabrata was studied by light and electron microscopy, with special attention to the budding process. Polysaccharides were also extracted to determine glycogen in cytoplasmic particles. Elliptical single cells, with a mean volume of 13 μm3, possess ultrastructural features common in other yeasts, viz. nucleus with double membrane and pores, nucleolus, endoplasmic reticulum, mitochondria, vacuoles, lipid bodies, ribosomes, tripartite plasma membrane, and fibrillar wall with outer electron-dense layer. Numerous pocket-like invaginations of varying size and orientation are formed by the plasma membrane. Buds seem to be preceded by an elaboration of such invaginations and by tubular profiles of the endoplasmic reticulum present in the area of the emerging bud. As the bud protrudes, it appears bounded by a layer of newly synthesized wall material. In general, this process is similar to that in other yeasts (e.g., Saccharomyces) but no vesicles were observed in the peripheral cytoplasm of the mother cell during the initial stages of budding. Various stages in the budding cycle are illustrated.
Direct and indirect observations of bacteria on marine pebbles
Authors: Batoosingh E. , Anthony E. H.
Published: February 2010

Numbers and kinds of bacteria growing on marine pebbles were studied. Rotating pebbles slowly for 3 h in 80% seawater in porcelain jars brought most of the bacteria into suspension so they could be counted by membrane filter culture technique. Pebbles stored at −15 °C showed little change in density of bacterial population.Pebbles from three Nova Scotian coasts had similar numbers of bacteria, an average of 3.45 × 105 bacteria/cm2, or about 1 bacterium per 300 μ2. Those from a fourth coast had a smaller population.Direct counts using incident-light fluorescent microscopy revealed 7 times the number detected by membrane filter counts, and that about 2% of the pebble surface was occupied by bacteria. There was greater variance in counts from pebble to pebble than on a given pebble.Eleven isolates indicated the predominant bacteria on pebble surfaces to be motile, Gram-negative, asporogenous rods with polar flagella, mostly Pseudomonas. Pigmented forms predominate and pleomorphism is common.
Stable coexistence of Rfi− factors in Escherichia coli
Authors: Khatoon Hajra , Iyer Rajul V.
Published: February 2010

Strains of Escherichia coli K12 constructed to bear combinations of pairs of Rfi− factors originating from other strains, have been found to maintain them stably in antibiotic-free media. Compatibility between these factors of the same fi type, which were all able to propagate a phage specific for one of them, was inferred from the absence of entry exclusion for the donor factor and their ability to coexist in the same cell without any selective pressure. The findings reported here indicate heterogeneity among this group of Rfi− factors. This conclusion is further supported by observations that some pairs of these Rfi− factors show no evidence of recombination.
Changes in the permeability of Escherichia coli during parasitization by Bdellovibrio bacteriovorus
Authors: Crothers S. F. , Robinson J.
Published: February 2010

Bdellovibrio bacteriovorus strain 6-5-S completed a typical infection cycle when incubated with E. coli ML 35 (lac i−z+y−) in 0.025 M Hepes buffer, pH 7.8, supplemented with 0.002 M CaCl2∙2H2O. Growth of this strain of B. bacteriovorus was optimal over the range of pH 7.5–8.5. No growth occurred at pH 6.5. The broad pH range may occur because a buffer per se is not required for growth and multiplication. The parasite failed to multiply in a two-membered culture unsupplemented with Ca2+ or Mg2+.Growth and multiplication of B. bacteriovorus in a two-membered culture were assessed by various parameters, including decrease in absorbance at 520 mμ, and release of materials absorbing at 260 mμ, and at 280 mμ. The onset of lysis of the host cell was accompanied by an increase in the release of materials absorbing at 260 mμ and at 280 mμ. The ratio of the absorbance of these materials at 280 and 260 mμ increased at the same time, from which it may be inferred that probably amino acids or proteins were being released.No β-galactosidase could be detected in the culture fluid of the two-membered culture. The infected E. coli cells were more permeable than uninfected cells to o-nitrophenyl-β-D-galactoside, and to the fluorescent dye 8-aniIino-1-naphthalenesulfonic acid.
Development of a diazinon-degrading bacterium in paddy water after repeated applications of diazinon
Authors: Sethunathan N. , Pathak M. D.
Published: February 2010

A decline in the brown planthopper control effectivity of diazinon was noticed after its continuous application to rice paddies for [Formula: see text] years at the International Rice Research Institute. In a study undertaken to determine the factor involved in this decline, rapid inactivation of diazinon was recorded within 3 to 5 days of its incubation with water from a rice field that had received several applications of diazinon. During the same period, its degradation in water from an untreated rice field was non-significant. This indicated the development of a degrading agent in paddy water following diazinon treatments.The inactivation of diazinon on incubation with water from treated fields was retarded if the incubation mixture was sterilized or kept anaerobically. Release of 14CO2 from 14C-diazinon was rapid from water of treated fields, but was inhibited when streptomycin was added to the system. A lag of 2 or 3 days, followed by a rapid degradation, was generally evident. Thus these data established the fact that aerobic biological agents, capable of degrading diazinon in paddy water, develop after diazinon applications. A bacterium, Arthrobacter sp., capable of metabolizing diazinon in the presence of ethyl alcohol or glucose was isolated from paddy water of treated fields.
Evidence for the release at low salt concentration of a lipid–protein–carbohydrate complex from isolated envelopes and whole cells of a marine pseudomonad
Authors: Buckmire F. L. A. , MacLeod Robert A.
Published: February 2010

The effect of divalent cations on the turbidity and pH of suspensions of isolated cell envelopes of a marine pseudomonad has been examined. As the concentration of Mg2+, Ca2+, or Mn2+ was increased the turbidity and pH of the suspensions increased. A concentration of 0.010 M of divalent cations produced the same turbidity in a suspension of cell envelopes as 1.0 M NaCl. The envelopes released soluble non-dialyzable material (Ndf) when suspended in 0.01 M NaCl but not when suspended in 0.001 M solutions of the divalent cations. Whole cells of the marine pseudomonad released an Ndf when suspended in 0.5 M sucrose. The Ndf from both cells and envelopes contained lipid, protein, and carbohydrate. Analytical ultracentrifugation of the Ndf from both cells and envelopes revealed the presence of only one major component with a sedimentation coefficient of 9.7 ± 0.07. Electrophoresis of Ndf gave rise to a component which stained for carbohydrate and another which stained for protein. Both moved to the anode.
Stabilization of poliovirus to 32P decay
Authors: Hughes Howard G. , Tershak Daniel R.
Published: February 2010

Suicide experiments with 32P-labeled poliovirus were performed with HeLa S3 cells. The results show that virus–cell complexes become increasingly refractory to 32P decay during the eclipse period, i.e., stabilization to 32P decay occurs during the first 3 h of infection. The data suggest that stabilization is probably due in part to the production of early RNA during the eclipse period because the presence of 32P in the medium during the first 2 h of growth sensitizes infective centers.
Search for antagonistic Actinomycetae in Libyan soils
Authors: El Dein Selim Mostafa Sabry Nour
Published: February 2010

The place of 135 streptomyces isolates from 39 soil specimens collected in different geographical regions of Libya has been determined in the scheme recommended by Pridham, Hesseltine, and Benedict. The streptomyces isolates fall into four groups of the system. The members of the grey series predominate, followed in order of frequency by the brown ones. The other series occur in negligible numbers. Section IV and VII were totally absent.Sixty-five percent of the isolates proved to be antagonists, including 50% active exclusively against Gram-positive, 3% active exclusively against Gram-negative, and 12% active equally against Gram-positive and Gram-negative microorganisms.A correlation between the organic content of the soil samples and the number of streptomyces was quite obvious. Soil richer in organic materials seem to contain fewer streptomyces strains than the poorer ones. The soils left untouched for long periods of time without cultivation may supply both numerically and qualitatively most of the antagonists.A rather interesting point is that in Libyan soils the incidence of antagonism to Gram-positive microorganisms is particularly high when compared with that in the other areas of the world.
Purification and kinetic studies of the hemolysin from Escherichia coli
Authors: Zwadyk Jr. Peter , Snyder I. S.
Published: February 2010

The hemolysin of Escherichia coli has been concentrated 23-fold by ethanol and ammonium sulfate precipitation. Further evidence has been presented that the hemolysin is a protein or peptide. Kinetic studies of the hemolytic reaction reveal a complex curve which consists of a lag, an area of accelerated reaction rate, and a plateau. Kinetic studies also show that the hemolytic reaction can be best demonstrated at a pH of 7.9 and a temperature of 30 °C using a 1% suspension of sheep erythrocytes.
Properties of polyoma virus transformed cells. I. Oncogenic properties
Authors: Babiuk Lorne A. , Hudson James B.
Published: February 2010

Studies were made on the oncogenic properties of a line of polyoma virus transformed hamster cells. Passage of the cells in vivo resulted in an increase in oncogenicity. Thus the latent period for the appearance of a tumor was decreased, and as few as 5 to 10 cells were now sufficient to produce a tumor in a young hamster. Tumors were invariably restricted to the subcutaneous site of injection. In contrast, polyoma virus itself caused widespread production of tumors throughout the animal. Histological examination of tumor tissue revealed marked differences between tumors caused by virus or virus-transformed cells. It was concluded that little or no metastasis of transformed cells could have occurred, and that insignificant rescue of the polyoma virus genome must have been induced in transformed cell tumors.Powassan virus, a group B arbovirus, did not show any oncolytic activity toward tumors induced by the polyoma virus transformed cells.
The intracellular development of vaccinia virus as observed in freeze-etched preparations
Authors: Easterbrook K. B. , Rozee K. R.
Published: February 2010

The site and structure of the viral inclusion can be easily seen in freeze-etched preparations of vaccinia-infected L-cells. It can be recognized not only by its content of virions but also by its granular nature which contrasts with the almost structureless cytoplasm. The granular material (viroplasm) appears to be incorporated into the developing immature virion in a condensed state. The inclusion is surrounded by ribosomes and a fibrous protein structure which appears to contain it, and is interspersed with membrane-bounded vesicles and vacuoles. Both the internal and external surfaces of the virions are visualized and appear similar to those observed in negatively stained preparations of isolated virions.
Effect of thermal injury on the TCA cycle enzymes of Staphylococcus aureus MF 31 and Salmonella typhimurium 7136
Authors: Tomlins Richard I. , Pierson Merle D. , Ordal Z. John
Published: February 2010

The heating of S. aureus MF-31 and S. typhimurium 7136 at 52C and 48C respectively, produced a sublethal heat injury. When injured cells were placed in fresh growth medium they recovered. The recovery of S. aureus was not inhibited by chloramphenicol. The metabolic activities of tricarboxylic acid (TCA) cycle enzymes, as well as other selected enzymes in crude extracts of normal and heat-injured cells of both microorganisms were assayed. In extracts from S. typhimurium there was some loss of specific activity with fumarate hydratase, glutamate dehydrogenase, fructose diphosphate aldolase, lactate dehydrogenase, and the NAD(P) oxidases as a result of heating. In extracts from S. aureus oxoglutarate dehydrogenase, malate dehydrogenase and lactate dehydrogenase were severely inactivated after heating. Other enzymes in comparison were only moderately sensitive to heat. No significant increase in enzyme activity was observed in extracts from injured cells of either microorganism. Re-naturation of lactate dehydrogenase and malate dehydrogenase occurred during the recovery of S. aureus both in the presence and absence of chloramphenicol. No renaturation of oxoglutarate dehydrogenase was found under the same conditions.
Intraspecific transduction in Staphylococcus epidermidis and interspecific transduction between Staphylococcus aureus and Staphylococcus epidermidis
Authors: Yu Ling , Baldwin J. N.
Published: February 2010

Phages were isolated from Staphylococcus epidermidis after exposure of cultures to mitomycin C. Using certain of these phages, genes controlling resistance to novobiocin, streptomycin, and erythromycin and genes involved in the synthesis of adenine and riboflavin were transferred from donor to recipient strains of S. epidermidis. Interspecific transduction of the Novr marker was accomplished between S. epidermidis and S. aureus. Attempts to transfer penicillin resistance were not successful.
The recovery of polyoma virus from infected mouse cells: relevance to virus purification
Authors: Kohse Larry M. , McGrath Lorraine , Hudson James B.
Published: February 2010

The desire to obtain maximum yields of polyoma virus from infected mouse tissue culture lysates prompted us to examine more closely the interaction between virus and cell fragments. The objective was to find the best and most economical means of alleviating this interaction, and allow quantitative recovery of the virus for further purification. Sonication of polyoma virus infected mouse-kidney cultures sufficed to release the virus in a form amenable to hemagglutinin assay. In contrast infected mouse embryo lysates required neuraminidase to effect maximum release. A variety of other enzymes and treatments were tested and found to be completely ineffective, or less effective than neuraminidase. However, in spite of the ability to effect release of virus at this stage, subsequent centrifugation to pellet the cell fragments always resulted in reattachment of the virus to these fragments. Complete elution of the virus then required several cycles of neuraminidase, trypsin, pH 8.5 treatments. It was shown that full and empty viral capsids behaved similarly.
Genetic and biochemical studies of the hexose monophosphate shunt in Neurospora crassa. I. The influence of genetic defects in the pathway on colonial morphology
Authors: Fuscaldo Kathyrn E. , Lechner John F. , Bazinet George
Published: February 2010

These investigations provide evidence that the N. crassa colonial mutants col-2 and col-3 are defective for two of the HMP shunt enzymes, G6PD and 6PGD respectively. Nutritional studies indicate that both mutants will revert to a more nearly wild-type morphology when they are grown on carbon sources capable of generating NADPH by alternative metabolic pathways. The HMP dehydrogenases are repressed when the organism is grown on acetate or low levels of glutamate. It appears that the lowered steady-state level of NADPH in the colonial mutants is the limiting factor in growth. The principal function of the shunt, apparently, is to supply the reduced NADP required by the cell for its major biosynthetic pathways. The genes coding for the two apparently coordinately controlled dehydrogenases are linked and may be part of a functional region regulating the HMP shunt.
Genetic and biochemical studies of the hexose monophosphate shunt in Neurospora crassa. II. Characterization of biochemical defects of the morphological mutants colonial 2 and colonial 3
Authors: Lechner John F. , Fuscaldo Kathyrn E. , Bazinet George
Published: February 2010

The two dehydrogenases of the hexose monophosphate shunt, glucose-6-phosphate dehydrogenase and 6-phosphogluconic acid dehydrogenase, were examined in two morphology mutants of Neurospora crassa. Glucose-6-phosphate dehydrogenase extracted from the mutant colonial-2 was found in an altered form as compared to the wild-type enzyme. The second enzyme of the pathway was observed to be abnormal in the mutant colonial-3. In addition, 6-phosphogluconic acid dehydrogenase was found to exhibit non-classical kinetics. The data indicate that the altered morphology exhibited by both colonial-2 and colonial-3 is due to the suboptimal capacity of the hexose monophosphate shunt to function normally. This physiological impairment of the pathway is reflected in a lowered cellular steady-state level of NADP.
Ségrégation indépendante des propriétés restrictives des facteurs R isolés au Canada en 1956–1957
Authors: Sonea S. , Săsarman A. , Surdeanu M. , Martineau B.
Published: February 2010

The nature of the resistance to various antibiotics of 55 strains of Escherichia coli O127: B8 isolated in Canada during 1956–1957 was examined. The resistance found in almost half of the strains segregated during transfer showing a hetero-R state. The most common type of the transferred resistance was due to the simultaneous presence of two R factors: R(Cm Neo) fi+ and R(Su) fi−. Other frequently transferred resistances were due to only a single factor: R(Su Sm Cm) fi+ or R(Cm Neo) fi+. Sixteen of the examined R factors, among them 6 fi+ and 10 fi−, could restrict phages BF23 and P1. The restrictive properties were frequently lost during transfer, without affecting the transferability of R factors. In 12 cases the restrictive factors could be obtained independently of resistance markers. Thus, restrictive properties may be sometimes due to accessory plasmids, accompanying non-restrictive R factors.
Initial temperature sensitivity of streptomycin-dependent and tryptophan transformants of Bacillus subtilis
Authors: McDonald W. C.
Published: February 2010

Cells of Bacillus subtilis transformed to str-d or trp+ display a period of temperature sensitivity. Normal thermal stability develops before division of the transformants.
Salt tolerance of intertidal marine bacteria
Authors: Forsyth M. P. , Shindler D. B. , Gochnauer M. B. , Kushner D. J.
Published: February 2010

A large proportion of bacteria isolated from the intertidal zone could grow in higher salt concentrations than found in seawater, and some could grow in saturated or near-saturated NaCl. Half the bacteria isolated could grow in media very low (0.06%) in NaCl; most of the Gram-positive organisms belonged to this group. There was no correlation between pigmentation and salt tolerance.
The effect of mitomycin C on the pyocine typing patterns of hospital strains of Pseudomonas aeruginosa
Authors: Tripathy G. S. , Chadwick P.
Published: February 2010

With a view to shortening the time required for pyocine typing and reducing the proportion of untypable isolates, the effect of inducing strains of Pseudomonas aeruginosa by mitomycin C was studied. Detailed experiments with two strains showed that mitomycin C enhanced pyocine production by a typable strain and allowed formation of pyocine by an untypable strain. Maximal production of pyocine was achieved using mitomycin C in a concentration of 0.5 μg/ml.Three hundred and thirty-six isolates of P. aeruginosa which had been typed by Gillies and Govan's method were retyped after induction by mitomycin C. Induction and typing were performed on the same agar plate, and a 6-h incubation period at 32 °C was found sufficient for pyocine production. A similar number of typing patterns were found by both methods, but 154 isolates showed a different pattern after induction, and 23 of 38 previously untypable strains became typable. The typing patterns observed after induction were reproducible, and at least as stable epidemiologically as those obtained without induction.