bluuebunny/crossref_metadata_2025 huggingface dataset:
THE LYSIS OF A PSYCHROPHILIC MARINE BACTERIUM AS STUDIED BY MICROELECTROPHORESIS
Authors: Madeley J. R. , Korngold R. R. , Kushner D. J. , Gibbons N. E.
Published: February 2010

Non-growing cells of a psychrophilic marine bacterium lyse if subjected to temperatures above 21 °C, to low ionic strengths, or to pH values below 6.0. Microelectrophoretic techniques were used to help determine the surface effects of cellular breakdown. During lysis, however induced, the cell populations became heterogeneous in mobility. This was apparently due to the adsorption of intracellular material, with a higher negative charge than intact cells, onto the cell surface. The mobilities of cells lysed in water or at acid pH reverted to the control values after repeated washings, which were thought to remove adsorbed intracellular material. Lysis induced by these latter treatments, therefore, did not involve the external cell surface. Water-lysed cells were stable at temperatures where both whole cells and mechanically prepared cell envelopes were subject to breakdown. After temperature-induced lysis, the washed cells possessed a higher negative mobility than intact cells, which was not due to the presence of adsorbed intracellular material, but rather to an irreversible surface change. Lysis in distilled water at 25 °C left the cell surface unchanged, and the "temperature effect" of a permanently increased negative charge was only evident when lysis at 25 °C preceded exposure to distilled water.
THE INFLUENCE OF GROWTH MEDIA ON PROTEINS BOUND TO DNA AND THEIR POSSIBLE ROLE IN THE RESPONSE OF ESCHERICHIA COLI B TO ULTRAVIOLET LIGHT
Authors: Webb S. J.
Published: February 2010

The deoxyribonucleic acid (DNA) from cells of Escherichia coli B, after rigorous extraction, was found to contain residual amounts of protein, the quantity of which was determined by the medium in which the cells were grown. The DNA of cells grown in a minimal salts medium contained from 10 to 15 times more protein than the DNA of cells grown in an enriched medium. The addition of amino acids, vitamins, or nucleic acid bases to the growth medium resulted in a decrease in the amount of residual protein and an increase in the sensitivity of the cells to ultraviolet light. Of the enrichments tested, the amino acids produced the greatest decrease in the quantity of residual proteins and the largest increase in sensitivity to ultraviolet. The type of mutant cell produced by ultraviolet irradiation was found to be strongly influenced by the ingredients of the growth medium. Few mutants were found after the irradiation of cells grown in the minimal salts medium but when the growth medium was enriched with amino acids, many mutants requiring amino acids appeared. Similarly the addition of vitamins or bases resulted in the production of vitamin-and base-requiring mutants. It is suggested that these residual proteins become attached to specific sites on the DNA during the operation of certain genes and this results in an increase in the ability of the DNA to withstand the damaging action of desiccation and ultraviolet light.
THE EFFECT OF 3000–4000 Å LIGHT ON THE SYNTHESIS OF β-GALACTOSIDASE AND BACTERIOPHAGES BY ESCHERICHIA COLI B
Authors: Webb S. J. , Bhorjee J. Singh
Published: February 2010

The irradiation of Escherichia coli B with sublethal doses of 3000–4000 Å light prevented the microorganisms from manufacturing β-galactosidase and T2 and T7 coliphages. Inhibition occurred only if the cells were irradiated immediately after their contact with the inducer lactose or infection with T2 and T7 phages. If, before irradiation the cells were allowed to incubate for 15 min after the addition of lactose or the coliphages to the cells, little effect of the light was found. The uptake of uracil and amino acids by washed cells was more rapid in the first 15 min than during later time periods while thymine uptake did not begin until the first 15 min had elapsed. The 3000–4000 Å light inhibited the uptake of arginine and thymine but not uracil or glutamic acid. The addition of 5% inositol inhibited the synthesis of β-galactosidase and the uptake of14C-labelled metabolites. Since there was a strong correlation between the degree to which arginine and thymine uptakes were inhibited by the light or inositol, it appears that the production of a protein during the first 15 min is intimately connected with DNA replication and the synthesis of induced enzymes.
THERAPEUTIC ACTIVITY OF LYSOSTAPHIN IN EXPERIMENTAL STAPHYLOCOCCAL INFECTIONS
Authors: Harrison Edward F. , Cropp C. Bruce
Published: February 2010

When tested in three experimental staphylococcal infections—acute peritonitis in mice, mouse leg edema produced by a localized infection, and dermal rabbit ear infections—lysostaphin demonstrated in vivo chemotherapeutic activity. Doses of less than 0.007 mg/kg (intraperitoneally) and 0.5 mg/kg (subcutaneously) of lysostaphin prevented death in 50% of the mice with acute staphylococcal peritonitis. A single intramuscular dose (0.15 mg/mouse) of lysostaphin suppressed the swelling produced by the injection of staphylococci into mouse legs to 50% of that produced in untreated animals. Lysostaphin (0.05% by weight) incorporated into gels and applied topically eradicated staphylococci from experimental skin lesions on the ears of rabbits. Lysostaphin was absorbed and transported by the body fluids from the point of injection to the site of the infection producing a desirable antistaphylococcal effect.
GROWTH OF FUSARIUM DIVERSISPORUM SHERB. ON LONG-CHAINn-FATTY ALCOHOLS OR CHOLESTEROL AS THE SOLE CARBON SOURCE
Authors: Strobel Rudolf G. , Quinn Herbert , Lange Willy
Published: February 2010

In well-aerated submerged cultures of Fusarium diversisporum Sherb. with n-hexadecanol or n-heptadecanol (which are virtually water insoluble) as the sole carbon source, the alkanols do not undergo extracellular chemical changes before assimilation but move, unchanged, through the cell wall faster than they can be metabolized by the organism and thus may constitute up to one-half of the total lipids in the cells. The alkanols are initially oxidized at the hydroxylated terminal carbon atom to fatty acids without loss of carbon. The fatty acids are subject to further metabolic action. Apparently carbon, not needed immediately for energy and for synthesis of cell components, is transformed into triglycerides as a reserve material. In these triglycerides, the distribution of the saturated and the unsaturated fatty acids between the primary and the secondary positions of the glycerol moiety is one typical of a vegetable lipid. Interesting differences exist, particularly in the sterol ester and phospho- or glyco-lipid contents, between mycelia grown on sucrose, hexadecanol, or heptadecanol. These cell constituents may possibly be involved in alkanol transport across the cell wall. The mold also assimilates cholesterol but has difficulty in metabolizing it.
CHEMICAL COMPOSITION OF HYPHAL AND SCLEROTIAL WALLS OF SCLEROTIUM ROLFSII SACC.
Authors: Chet I. , Henis Y. , Mitchell R.
Published: February 2010

The chemical components of the sclerotial and hyphal walls of the fungus Sclerotium rolfsii Sacc. are compared. Sclerotial walls contain a melanin-like pigment which is absent from hyphal walls. They are also higher in non-hydro-lyzable residue, in lipids, and in ash content. In both walls, glucose, mannose, and glucosamine are found after acid hydrolysis. Acid hydrolysates of sclerotial and hyphal walls contain 10 and 13 amino acids, respectively, L-arginine, L-serine, and L-proline being absent from sclerotial walls. The possible role of some of these components in the resistance of the sclerotia to biological and chemical degradation is discussed.
THE METABOLISM OF PHENYLACETIC ACID BY A PSEUDOMONAS
Authors: Blakley E. R. , Kurz W. , Halvorson H. , Simpson F. J.
Published: February 2010

A Pseudomonas species adapted to grow on phenylacetic acid is simultaneously adapted to the utilization of phenylacetic acid, p-hydroxyphenylacetic acid, and 3,4-dihydroxyphenylacetic acid. Extracts of the organism catalyze the oxidation of p-hydroxyphenylacetic acid and 3,4-dihydroxyphenylacetic acid, but not phenylacetic acid. The addition of NAD or NADH to extracts is required for maximum utilization of p-hydroxyphenylacetic acid; ferrous ion is required for maximum utilization of 3,4-dihydroxyphenylacetic acid. The oxidation of 3,4-dihydroxyphenylacetic acid results in the production of a compound having an absorption maximum at 318 mμ in acid and at 380 mμ in alkali, which was identified as δ-carboxymethyl-α-hydroxymuconic semialdehyde. The degradation of phenylacetic acid by this organism follows a pathway that utilizes p-hydroxyphenylacetic acid and 3,4-dihydroxyphenylacetic acid as intermediates.
THE MICROBIAL PRODUCTION AND SOME CHARACTERISTICS OF δ-CARBOXYMETHYL-α-HYDROXYMUCONIC SEMIALDEHYDE
Authors: Blakley E. R. , Halvorson H. , Kurz W.
Published: February 2010

Suspensions of Pseudomonas grown on phenylacetic acid oxidized 3,4-dihydroxy-phenylacetic acid to δ-carboxymethyl-α-hydroxymuconic semialdehyde. The compound was characterized by conversion to 2,5-pyridine dicarboxylic acid. The results show that cleavage of the aromatic ring occurs between carbons 2 and 3. δ-Carboxymethyl-α-hydroxymuconic semialdehyde is relatively unstable. Maximum absorption of the compound is obtained in acid at 318 mμ and in alkali at 380 mμ. The ratio of optical densities (380/318) is 1.8. In 2% sodium carbonate solution the molar extinction coefficient at 380 mμ is 2.7 × 104. Other chemical properties of the cleavage product are described.
THE EFFECT OF THE GAMMA-ISOMER OF BENZENE HEXACHLORIDE UPON THE MICROFLORA OF SUBMERGED RICE SOILS: I. EFFECT UPON ALGAE
Authors: Raghu K. , MacRae I. C.
Published: February 2010

The effect of additions of the gamma-isomer of benzene hexachloride (gamma-BHC) upon algal populations in two submerged tropical rice soils was studied. Additions of the insecticide to the floodwaters of the soils at 5, 6, and 50 kg/ha active compound resulted in a marked stimulation of growth of the indigenous algae. The stimulation was attributed to the elimination by the insecticide of small animals which feed on the algae. No detrimental effect upon total algal populations was found when gamma-BHC was applied at 50 kg/ha, which is 10 times the rate recommended to control the rice stem borer. Qualitative changes were detected in the incidence of major algal groups. Blue-green algae were more abundant in treated soils whereas the green algae and diatoms were more abundant in the untreated soils. Much larger amounts of algal tissue were produced in the floodwaters treated with gamma-BHC. The possible effects of increased algal development on the fertility of the soil and the persistence of gamma-BHC in submerged soils are discussed.
SOIL MICROORGANISMS ASSOCIATED WITH FLAX ROOTS
Authors: Peterson E. A. , Rouatt J. W.
Published: February 2010

The root microflora of Bison flax, resistant to wilt caused by Fusarium oxysporum f. lini, was compared with that of the wilt-susceptible variety Novelty. Plants grown in "disease-free" soil show that the susceptible variety harbors not only the most numerous, but also the most metabolically active bacterial flora on its roots. Generic classification of bacterial isolates shows a higher incidence of more active organisms, represented by Pseudomonas and Flavobacterium on roots of the susceptible crop, whereas the more slowly growing pleomorphic types such as Arthrobacter were most abundant on roots of the resistant variety. Fungi were also more numerous on roots of the susceptible crop, but the generic composition of rhizosphere populations of both varieties was similar to that of the soil itself. Fusarium oxysporum dominated the flora occurring in an active mycelial state on roots of the susceptible variety, whereas F. oxysporum and Phoma sp. were codominants in the active flora of the resistant crop. Tests with other soils showed that dominance of specific genera varies with soil type. The results indicate a selective action on the root microflora, particularly the bacteria, and suggest both quantitative and qualitative differences in root environments of the two flax varieties.
A COMPARISON OF THE OSMOTIC AND PASSIVE PERMEABILITY PROPERTIES OF MYCOPLASMA LAIDLAWII AND MYCOPLASMA HOMINIS
Authors: Spears Doris M. , Provost Philip J.
Published: February 2010

Turbidity variations induced by a variety of solutes at known levels of osmolality were determined in suspensions of Mycoplasma laidlawii and Mycoplasma hominis. Turbidity values were corrected for refractive index effects using Ficoll solutions. The two organisms differed in passive permeability properties, cell refractilities, estimated internal osmotic pressures, and cation stabilization effect. More specifically, M. laidlawii gave large turbidity responses, interpreted as caused by osmotic influences on cell volume, to potassium and sodium chlorides, sodium acetate, and sucrose. In addition a non-osmotic enhancement of turbidity was produced by potassium and sodium salts. Glucose, glycerol, and dimethylsulfoxide induced little turbidity variation. Of the above solutes, only glycerol and dimethylsulfoxide failed to induce maximum turbidity responses in M. hominis. M. laidlawii appeared to be more retractile and had higher estimated internal osmotic pressure values than M. hominis. These differences undoubtedly reflect properties of the enclosing cell membranes that are unlike in the two organisms. Their pertinence to saprophytic versus parasitic existence is obscure at the present time.
CORRELATION OF PHYSIOLOGICAL CHARACTERISTICS WITH NODULATING ABILITY IN RHIZOBIUM JAPONICUM
Authors: Hubbell D. H. , Elkan G. H.
Published: February 2010

A nodulating soybean strain and a mutant, non-nodulating sister soybean strain, and several strains of Rhizobium japonicum differing in nodulation response on these two plant hosts, were used to study specific biochemical requirements of the nodulation process. Screening of the bacterial strains revealed five physiological properties which correlated with ability or inability to nodulate the mutant soybean. High measurable indoleacetic acid formation, low indoleacetic acid destruction, high capsule formation, failure to metabolize nitrite, and failure to reduce triphenyl tetrazolium chloride were properties associated with ability to nodulate both normal and mutant soybeans. These same properties, opposite in magnitude, were associated with ability to nodulate only the normal soybean. These correlations were tested further by screening additional Rhizobium strains for the same properties. On the basis of the results obtained, nodulation response of the new strains on the mutant soybean was predicted. Only three of the five properties, namely low capsule formation, ability to metabolize nitrite, and ability to reduce triphenyl tetrazolium chloride, were present in all of the new strains. On the basis of these results it was predicted that these strains would not nodulate the mutant soybean. In subsequent nodulation tests, all strains failed to nodulate the mutant soybean. It was concluded from these experiments that high capsule formation, inability to metabolize nitrite, and failure to reduce triphenyl tetrazolium chloride are associated with the increased effectiveness of the rhizobial strains which nodulate both normal and mutant soybeans.
STRAIN ALTERATION IN ENTERIC BACTERIA ISOLATED FROM RIVER WATER
Authors: Hendricks Charles W. , Morrison S. M.
Published: February 2010

Enteric bacteria recovered from the Cache la Poudre River and refrigerated for approximately 3 months were observed to form sectored colonies on MacConkey agar subculture. Organisms taken from each sector of the colonies were compared and a wide range of biochemical and serological variation was observed. Selected variant characteristics observed in the pure culture isolates from the sectored colonies were shown to be reproducible with membrane filter U tubes. Further investigation revealed that the agent responsible for the observed variations was submicrobial, survived chloroform and heat (56 C for 30 minutes) treatments, and produced occasional lysis in the non-lactose-fermenting strains. Additional cultures resembling the original variant organisms were recovered from the river but attempts to produce the sectoring phenomenon with these organisms were without success, although numerous sectoring isolates having similar variant characteristics were recovered from the stream.
PREPARATION AND CHARACTERIZATION OF INTACT AND FREE SPORES OF BACILLUS POPILLIAE DUTKY
Authors: Julian Grant St. , Pridham Thomas G. , Hall Harlow H.
Published: February 2010

Spores of Bacillus popilliae are enclosed within a large sporangium. In an effort to characterize the spores precisely, a method was developed to free them from their sporangia by sonic vibration. Separation of the free spores from sporangial debris was made by lysozyme treatment, centrifugation, and the Sacks and Alderton aqueous polymer two-phase system. The intact spores are fully refractile; they accept and retain malachite green applied by a modified Wirtz spore-staining technique. The free spores are elongated with rounded ends and measure 1.30–2.25 μ × 0.90–1.40 μ. Outgrowth of intact germinated spores is lowest when heat-activated at 80 °C and highest when heat-activated at 50 °C. Free spores are more heat sensitive than are intact spores, possibly because of damage by the sonic treatment. L-Alanine, adenosine, and glucose separately and in combination do not influence germination of either intact or free spores. Although potassium phosphate somewhat increased germination of intact spores, other salts were ineffective, but almost all salts increased germination of free spores.
EFFECT OF TEMPERATURE ON RADIATION RESISTANCE OF SPORES OF CLOSTRIDIUM BOTULINUM 33A
Authors: Grecz N. , Upadhyay J. , Tang T. C.
Published: February 2010

Spores of Clostridium botulinum 33A in two suspending media, phosphate buffer and pork pea broth, were gamma irradiated at radiation temperatures from +20 °C to −196 °C. The liquid–solid transition around 0 °C introduced a one-step plateaulike change in radiation sensitivity of spores. The spores were considerably more resistant in the solidly frozen medium than in the liquid medium. The solid state reduced indirect effects of radiation by physical blocking of secondary radicals. The one-step transition was much smaller in pork pea broth than in buffer. This indicated that scavenging of secondary radicals by pork pea broth caused a considerable reduction of indirect effects of radiation, but did not completely eliminate them.Freezing alone did not eliminate all indirect effects. This was evident from the gradual reduction in radiation sensitivity of spores in the solidly frozen phosphate buffer betweeen −25 °C and −196 °C. Furthermore, even at −196 °C indirect effects of radiation remained active since (a) spore survival did not level off with respect to temperature and (b) the lethal efficiency of radiation was still appreciably greater in phosphate buffer than in pork pea broth at −196 °C.In frozen pork pea broth at −25 °C to −196 °C temperature had no effect on radiation sensitivity of spores. This indicated that spores were killed by direct hits; apparently physical blocking by the solidly frozen medium, plus radical scavenging by pork pea broth eliminated all indirect effects of radiation.
DEVELOPMENT OF A METHOD FOR THE TOTAL COUNT OF MARINE BACTERIA ON ALGAE
Authors: Chan E. C. S. , McManus Elizabeth A.
Published: February 2010

In an initial attempt to develop a technique for the enumeration of bacteria on littoral algae, the authors observed that homogenization of the algal samples in the Waring Blendor resulted in the death of the marine bacteria contained in the samples. Further work on this lethal effect of blending showed that two detrimental factors, heat and mechanical injury of the cells, were implicated. These factors were due to the increase in temperature during homogenization and the high speed of rotation of the knife-blade assembly of the Waring Blendor. From these findings, a satisfactory technique was formulated for obtaining homogenates of marine materials for the total count of bacteria. This involved homogenization at speeds of about 5000 r.p.m. (using a Servall Omni-Mixer homogenizer) and a temperature of homogenization not exceeding 30 °C.
BOUND WATER, INOSITOL, AND THE INDUCTION OF LAMBDA PROPHAGES BY ULTRAVIOLET LIGHT
Authors: Webb S. J. , Dumasia M. D.
Published: February 2010

Lysogenic cells of Escherichia coli K12 (λ+) and Escherichia coli M3 (λ59) were held in atmospheres having relative humidities (R.H.) from 30% to 80% and irradiated with 2537 Å ultraviolet light (uv.). The colony-forming ability of both types of cell was destroyed more rapidly at 55% R.H. than at any other level of R.H. With E. coli K12 (λ+) the percentage of cells in which prophage induction occurred increased as the dose of ultraviolet light increased and the maximum number of inductions occurred at 55% R.H. Inositol prevented (λ+) prophage induction but was less effective in doing so at 55% R.H. Desiccation alone induced the (λ59) prophage and subsequent uv. irradiation resulted in the destruction of the prophage. The maximum rate of destruction was found at 55% R.H. Inositol prevented the uv. inactivation of the (λ59) prophage, resulting in an increase in inductions with uv. dose at 30% R.H. The free phages were found to have the same sensitivity to ultraviolet light as the induced prophages but were less protected by inositol.It is proposed that water molecules hold the prophage to or in the host DNA and that ultraviolet light induces the prophage and destroys its integrity by reorientating these water molecules.
A RAPID MICRO TISSUE CULTURE ASSAY IN BS-C-1 CELLS FOR THE TITRATION AND NEUTRALIZATION OF MEASLES VIRUS
Authors: Moreau Pierre , Furesz John
Published: February 2010

A simple, rapid and reproducible micro tissue culture assay in the BS-C-1 (Cercopithecus monkey kidney) cell line was developed for the titration and neutralization of measles virus. Serial dilutions of virus (or serum) were made with spiral loops in disposable microplates and 8 × 103BS-C-1 cells suspended in 0.05 ml of medium 199 with 2% fetal bovine serum were added to each dilution. After the addition of 0.1 ml of sterile mineral oil to each microculture, the plates were covered with a plexiglass sheet and placed in a humidified incubator (37 °C) under a constant pressure of 5% CO2for S days. Micro tissue cultures were examined with the aid of an inverted microscope for viral cytopathic changes on the fourth and fifth day.The micro assay was applied to the virus titration of various live, attenuated measles vaccines, as well as to the antibody titration of human and animal sera following vaccination with either live or inactivated measles vaccines.
INFLUENCE OF NAFCILLIN ON THE ENZYMIC LYSIS OF STAPHYLOCOCCUS AUREUS
Authors: Warren George H. , Gray Jane
Published: February 2010

During growth of Staphylococcus aureus cells, sublethal concentrations of nafcillin induce changes in the cell wall resulting in a pronounced increase in susceptibility to lysis by lysozyme and proteolytic enzymes. Data presented demonstrate that this property of nafcillin is dose dependent, and the relatively low concentration needed to influence lysis significantly, approximately 1/80th the minimum inhibiting concentration, suggests that we are dealing with a specific and primary action on cell wall synthesis. The enhancement in lytic response observed during the logarithmic phase of growth is consistent with the hypothesis that an impairment of cross-linking in mucopeptide synthesis occurs following exposure to nafcillin. Since heat treatment (60 °C, 20 min) of nafcillin-treated cells considerably reduces lysis, the rate and extent must depend in part on the activity of one or more autolytic factors. Enzymic lysis is also enhanced by addition of sodium bicarbonate to control and nafcillin-treated suspensions, a phenomenon interpreted as a reversible bicarbonate-induced effect on cell permeability.
AUTORADIOGRAPHIC STUDIES OF BACTERIAL CELL WALL REPLICATION: I. CELL WALL GROWTH OF BACILLUS CEREUS IN THE PRESENCE OF CHLORAMPHENICOL
Authors: Chung K. L.
Published: February 2010

The pattern of cell wall synthesis as measured by the incorporation of tritiated alanine into the cell wall of Bacillus cereus, and the number of synthesizing sites in the cell wall were studied by the direct and the reverse autoradiographic labelling methods.In the absence of chloramphenicol, the new cell wall was initiated at two or three segments, and later increased to four or five segments which continued to elongate but not to increase in number until the bacilli had made preparation for cell division. Shortly before the centripetal growth of the cell wall and constriction to separate daughter cells, two to three more new wall-segments were added to those already present. The second and third generation cells retained some old wall-segments from the first-generation mother, which remained as discrete clusters of grains, and could easily be distinguished from the new segments.In the presence of chloramphenicol, the new wall was initiated at 8 to 10 sites. Further incubation resulted in the uniform incorporation of labels at multiple sites along the entire cell length.The patterns of new wall replication as studied by the two methods were compared. To account for the difference in synthesizing sites when chloramphenicol is present, it is suggested that the cells have either used the maximum number of sites or have completely bypassed all the sites and allowed the tritiated alanine to diffuse into the wall to become incorporated.
THE EFFECT OF NUTRIENTS AND ENVIRONMENT ON SYNNEMATA FORMATION OF STILBELLA THERMOPHILA
Authors: Al-Hassan K. K. , Fergus C. L.
Published: February 2010

Stilbella thermophila Fergus was grown on a chemically denned medium of D-glucose, KNO3, MgSO4, KH2PO4, agar, and microelements to determine the effect of environment and nutrition on growth and synnemata production. An exogenous supply of thiamine stimulated growth markedly on pyridine-purified agar, but both thiamine and biotin were required for synnemata to form. Pyrimidine was the effective moiety, not thiazole. S. thermophila grew on a large number of carbon and nitrogen compounds substituted singly into the basal medium, but synnemata formed on less than half of such media. Sucrose did not inhibit synnemata formation with glucose present, but no synnemata formed with sucrose in the medium even with a number of different nitrogen sources. Synnemata production followed chance mold contamination on a few of the media that normally did not allow their production. The carbon–nitrogen ratio significantly affected synnemata formation. So did pH, concentration of phosphate buffer, and temperature. At suboptimal temperatures, reduced synnemata, or only loose bundles of conidiophores, formed. Light was not required for synnemata initiation nor for maturation. Synnemata formation occurred over a narrower range of temperature, pH, vitamin concentration, nutrient concentration, and nutrient spectrum (carbon and nitrogen sources) than did mycelial growth.
SOME OBSERVATIONS CONCERNING DNA AND β-GALACTOSIDASE SYNTHESIS IN ESCHERICHIA COLI B
Authors: Webb S. J. , Bhorjee J. Singh , Walker Janet L. , Rokosh D. A.
Published: February 2010

When starved cells of thymine-requiring Escherichia coli B were placed in a complete induction medium there was an initial lag of 10 minutes before measurable amounts of the enzyme were detected. Cells exposed for 15 minutes to one inducer and then given an alternative inducer continued to manufacture the enzyme for 60 minutes at a rate characteristic of the initial inducer. After this period, enzyme manufacture assumed the characteristics of the second inducer. Glucose or mitomycin was found to inhibit enzyme synthesis only when they were added during the first 10 minutes or 45- to 60-minute periods of induction. Chloramphenicol stopped enzyme synthesis at any stage of induction. The synthesis of DNA was found to occur in two stages and enzyme synthesis was prevented by glucose or mitomycin only if they were added to the cells during a 10-minute period which immediately preceded DNA replication. It is concluded that a gene can express itself only once, and change in expression requires the synthesis of new DNA.
ROLE OF THIOBACILLUS FERROOXIDANS IN THE OXIDATION OF SULFIDE MINERALS
Authors: Duncan D. W. , Landesman J. , Walden C. C.
Published: February 2010

Selective inhibitors of iron and sulfide oxidation, sodium azide and N-ethylmaleimide respectively, were used to demonstrate that washed cell suspensions of Thiobacillus ferrooxidans attacked both insoluble ferrous iron and sulfide during the oxidation of chalcopyrite (CuFeS2) and pyrite (FeS2). The oxidation of the two substrates occurred simultaneously and independently but the relative rates depended on how the cells were grown. When chalcopyrite-grown cells were used to oxidize chalcopyrite, 68–74% of the oxygen uptake was the result of sulfide oxidation and 25–30% the result of iron oxidation. With pyrite, all the oxygen uptake was due to sulfide oxidation. When iron-grown cells were used to oxidize chalcopyrite, two rates resulted. During the initial rapid rate, 80–90% of the oxygen uptake was due to iron oxidation, but, during the second slower rate, the result duplicated those found with chalcopyrite-grown cells. Iron-grown cells oxidized pyrite at a constant and more rapid rate than chalcopyrite-grown cells. The faster rate was due to iron oxidation; since only 20–30% of the total oxygen uptake was due to sulfide oxidation.
TIME-LAPSE CINEMATOGRAPHY OF VANCOMYCIN-TREATED MICROBIAL CELLS
Authors: Durham Norman N. , Noller Eric C. , Burger Mike W. , Best Gary K.
Published: February 2010

The incubation of Bacillus subtilis W23 or Bacillus cereus on a vancomycin-containing medium resulted in a rapid contraction or shrinkage of the cells which was followed by lysis. The ejection of protoplasm from the cell during lysis was very forceful. The "burst" of protoplasmic material was observed at the ends of the cell and at one or two sites on the lateral cell wall. The results are consistent with the hypothesis that vancomycin inhibits cell wall synthesis and ultimately destroys the normal structure and integrity of the wall.
EFFECT OF HYPERBARIC OXYGEN UPON ANAEROBIC STREPTOCOCCI
Authors: Fredette V.
Published: February 2010

not available
VACUOLES OF FUNGAL PROTOPLASTS
Authors: Garcia-Acha I. , López-Belmonte F. , Villanueva J. R.
Published: February 2010

Details are given of the conditions which allow vacuolar structures of Fusarium culmorum to be released after osmotic bursting of mycelial protoplasts. Steps in the release of vacuoles are shown. The composition of the suspending medium affects the formation, size, and number of the vacuoles seen in the protoplasts. Fusion of vacuoles in regenerating protoplasts has been observed, indicating a self-sealing property of the tonoplast. Preparations of vacuolar structures, rather free from cytoplasmic debris, have been obtained.
SYNCHRONOUS PRODUCTION OF CONIDIOPHORES AND CONIDIA OF NEUROSPORA CRASSA
Authors: Stine G. J. , Clark Arnold M.
Published: February 2010

Neurospora mycelia were grown in Vogel's medium N. The mycelia were harvested and vacuum filtered to yield moist, mycelial mats 2 to 3 mm thick. The mycelial mats were placed in Petri dishes and incubated at 25°. On or about the third hour of incubation conidiophores appeared over the mycelial surface. The conidiophores differentiated into conidia on or about the eighth hour of incubation. The production of conidia continued for approximately 8 hours.The addition of 0.05 M malonate to the growth medium synchronized the appearance of the conidiophores on harvested moist mats of mycelia. The conidiophores so produced also approached synchrony in their differentiation into conidia. The uniformity of conidiophore production and the differentiation of conidiophores into large numbers of conidia were also influenced by both the length of aeration of the submerged mycelia and by treatment of the harvested mycelial mat with different buffers.There appeared to be a difference in the rate of germination for conidia harvested at different times from conidiophores of harvested mycelial mats. However, there was little difference in the germination rate for conidia produced from conidiophores of harvested mycelial mats and similar aged conidia grown on solidified medium N. The conidia, regardless of age or culture technique, retained a random capacity to germinate.
CONTINUOUS CULTURE OF ANAEROBIC RUMEN BACTERIA: MODIFICATION AND EXTENSION OF THE CYCLONE COLUMN CULTURE SYSTEM
Authors: Kistner A. , Zyl J. G. van
Published: February 2010

The requirements for a continuous culture system for extended studies of the growth physiology of functional rumen bacteria are outlined and the choice of Dawson's (1963) cyclone column culture vessel as the basis for further development is explained. The modifications required for establishment and maintenance of anaerobiosis, for pH control and for increasing the reliability and utility of this system are described. The general performance of the modified system is discussed and illustrated by results obtained during extended runs with a strain of Ruminococcus albus and a Butyrivibrio species.
INVESTIGATIONS INTO THE BASIS OF MICROBIAL ECOLOGY IN SOIL, ILLUSTRATED WITH REFERENCE TO GROWTH OF SOIL DIPHTHEROIDS AND AZOTOBACTER IN A MODEL SYSTEM
Authors: Tribe H. T. , Williams Pamela A.
Published: February 2010

Soil is regarded as consisting of a number of microbial habitats or ecological niches. Each niche is made up of three factors: substrate, environment, and time. A model system was used to simulate a niche reasoned to occur in field soils and to be occupied by heterotrophic bacteria. The system comprised a particulate substrate (dried yeast) mixed in a porous environment (sand) maintained over periods of up to 1 year. Yeast and sand were placed in special culture tubes which were inoculated with known numbers of bacteria suspended in mineral salt solution. This was distributed evenly through the sand by a suction method. The fate of single and mixed populations of three species of soil bacteria was followed by plate counts and microscopical observations. The bacteria were Arthrobacter globiformis, a second soil diphtheroid, and Azotobacter chroococcum. Both diphtheroids grew and persisted well either in single or mixed culture. Populations of azotobacter grown singly initially maintained their numbers, but then declined progressively; they declined more rapidly in association with the second soil diphtheroid, and abruptly to zero with A. globiformis.
GERMINATION OF BACTERIAL ENDOSPORES WITH SUBTILOPEPTIDASES
Authors: Sierra Gonzalo
Published: February 2010

Intact spores of Bacillus subtilis are susceptible to subtilopeptidase attack and this enzymatic reaction induces changes in the spore similar to those that take place during "physiological" germination. Germination occurred between pH 5.5 and 10.0 showing a pH optimum of 9.0 and between 25 °C and 45 °C with an optimum of 37–40°. Subtilopeptidase-induced germination took place in completely anaerobic conditions. Sublethal heating of spore suspensions increased the rate of subtilopeptidase-induced germination. Germination with subtilopeptidase was almost completely inhibited by an excess of diisopropyl fluorophosphate. L-Alanine-induced germination was not affected by diisopropyl fluorophosphate. Participation of the spore metabolism in subtilopeptidase-induced germination seemed likely. These results suggest that subtilopeptidases initiate spore germination by releasing germination agents from the spore.No significant loss of viability was noted until after exposure to the proteolytic enzyme for at least 60 minutes. Prolonged exposure of B. subtilis spores to subtilopeptidase results in death of the exposed spores.Subtilopeptidase-induced germination was also observed in several spores of other members of the genus Bacillus.
RICKETTSIA CANADA: A NEW MEMBER OF THE TYPHUS GROUP OF RICKETTSIAE ISOLATED FROM HAEMAPHYSALIS LEPORISPALUSTRIS TICKS IN CANADA
Authors: McKiel John A. , Bell E. John , Lackman David B.
Published: February 2010

A third species has been added to the typhus group of rickettsiae. This new rickettsia was isolated from Haemaphysalis leporispaluslris ticks removed from indicator rabbits in the vicinity of Richmond, Ontario. Inoculation of tick suspensions into embryonated hens' eggs was the method of culture. Results of complement fixation tests with guinea pig, hamster, and rabbit antisera showed that it is a member of the typhus group while results with antiserum prepared in mice suggested that it is different from the two known species, Rickettsia typhi and Rickettsia prowazeki, in the group. Results of toxin neutralization tests furnished the final proof that this is a new species of rickettsia. The name Rickettsia canada is proposed for it.
THE METABOLISM OF PUTRESCINE (1,4-DIAMINOBUTANE) BY MYCOBACTERIA ISOLATED FROM FISH: I. PRELIMINARY STUDIES WITH INTACT CELLS
Authors: Evelyn T. P. T.
Published: February 2010

Three mycobacterial strains isolated from fish were tested for their ability to metabolize various amines, supplied individually as sources of carbon. A series of six aliphatic and two cyclic amines was used. Growth occurred only with putrescine. The ability to oxidize putrescine was enhanced by growing the cells in the presence of the compound. Putrescine did not appear to influence the rate of endogenous respiration and therefore O2uptake values were corrected for endogenous O2uptake. During the oxidation of putrescine by washed cells, O2uptake curves "broke" at a point corresponding to 41–44% of the maximum level of oxidation. Thereafter, very small increases in O2uptake occurred so that on the completion of experiments, the level of oxidation corresponded to 45–47%. At this point, 69–76% of the amino nitrogen of putrescine was released as ammonia, the rest being assimilated. Using putrescine-1,4-14C under CO2-free conditions, approximately 75% of the terminal carbons were evolved as14CO2. Since the data suggested that carbons 2 and 3 were assimilated, CO2production accounted for a loss of 37.5% of putrescine carbon. When washed cells oxidized putrescine-1,4-14C, cell fractions containing lipid, nucleic acid, and protein were rapidly labelled.
THE METABOLISM OF PUTRESCINE (1,4-DIAMINOBUTANE) BY MYCOBACTERIA ISOLATED FROM FISH: II. STUDIES WITH ARSENITE-INHIBITED CELLS AND CELL-FREE EXTRACTS
Authors: Evelyn T. P. T.
Published: February 2010

Three mycobacterial strains isolated from fish degraded putrescine by a pathway in which γ-aminobutyraldehyde (Δ′-pyrroline), γ-aminobutyric acid, succinic semialdehyde, and succinic acid were intermediates. These results agree substantially with those of other workers using different microorganisms. Intact cells utilized γ-aminobutyric acid in a transaminase reaction with endogenously supplied α-ketoglutarate to produce succinic semialdehyde and glutamate. Studies with arsenite-poisoned cells showed that a significant proportion of putrescine was metabolized via pyruvate and alanine. When putrescine-1,4-14C was substrate, HCl extracts of cells contained radioactive aspartate and glutamate in addition to alanine. The further metabolism of succinate therefore proceeded in two directions: one yielding oxalacetate and α-ketoglutarate by way of the tricarboxylic acid cycle, and the other branching off the cycle to yield pyruvate. Studies with cell-free extracts suggested that putrescine nitrogen was assimilated via glutamate, which served as the amino-group donor to yield alanine and aspartate.
SOME EFFECTS OF MEDIUM COMPOSITION AND METABOLIC INTERMEDIATES ON BIOTIN INHIBITION IN A STRAIN OF RHIZOBIUM JAPONICUM
Authors: Elkan Gerald H.
Published: February 2010

Growth of Rhizobium japonicum No. 508 in a mineral salts – mannitol medium with 0.01 M NH4Cl and 0.2 g/l casein hydrolysate as nitrogen sources was inhibited by as little as 0.001 μg/l biotin. When 0.01 M NH4Cl and 0.2 g/l glutamic acid were the nitrogen sources, biotin inhibited growth at a concentration of 0.1 μg/l. Growth inhibition by biotin was observed in various defined media. When vitamin-free casein hydrolysate was the organic nitrogen source, there was slightly less inhibition. However, the degree of inhibition remained independent of the casein concentration. Additions of amino acids did not affect the inhibition. The effect was minimal when the organism was grown in medium containing undefined yeast extract even in the presence of added biotin. In such medium, growth was stimulated by the addition of avidin. When biotin was added to an actively growing culture, no inhibition occurred. If the biotin was removed from an inhibited culture, growth was reestablished. In media containing α-ketoglutarate, biotin did not inhibit growth of the organism, and with succinate, biotin was slightly stimulatory.
GLUCOSE REPRESSION OF OXIDATION OF ORGANIC COMPOUNDS BY SPHAEROTILUS
Authors: Stokes J. L. , Powers Margaret T.
Published: February 2010

Sphaerotilus discophorus and Sphaerotilus natans, when grown in media containing glucose, exhibit a very limited capacity to oxidize sugars, amino acids, and compounds of the tricarboxylic acid cycle. However, when grown in the absence of glucose, these species oxidize the above compounds rapidly and extensively. It appears, therefore, that growth with glucose represses synthesis of many enzymes in Sphaerotilus.
A COMMENT ON THE NUTRITIONAL GROUPING OF SOIL BACTERIA
Authors: Sundman Veronica , Calberg Gunnel
Published: February 2010

Bacterial isolates (512), mostly from forest soil, were studied by nutritional grouping methods. When glucose (the customary carbon source) was augmented with lactate, glycerol, acetate, and citrate, about 17% more organisms were able to develop in media containing mineral nitrogen.
SEROLOGICAL COMPARISONS BETWEEN STRAINS OF AGROBACTERIUM TUMEFACIENS
Authors: Hochster R. M. , Cole S. E.
Published: February 2010

Agrobacterium tumefaciens B6and Agrobacterium tumefaciens B6TP were compared serologically. Antigen–antibody precipitations produced by the use of the agar double-diffusion technique show cross reactions indicating similarity in addition to a line of precipitation specific for the virulent strain, Agrobacterium tumefaciens B6.
MICROBIAL UTILIZATION OF SOIL HUMIC ACIDS
Authors: Mathur S. P. , Paul E. A.
Published: February 2010

Soil organisms capable of growth on humates were isolated by direct plating and enrichment culture techniques. A strain of Penicillium frequentans, which was selected for further studies, utilized 32% of the humates supplied in replacement-shake cultures. Elemental and spectroscopic analyses of the 'original' and 'surviving' humates showed that the fungus preferred the aromatic moiety to the non-aromatic, nitrogen-rich portion as a source of carbon.Gel filtration studies demonstrated that 69% of the humates had molecular weights between 5000 and 50,000. The fraction (13%) with molecular weight above 50,000 was degraded to the largest extent, resulting in the production of some intermediate and small-sized molecules.It was suggested that this strain of penicillium was suitable for biodegradation studies aimed at characterizing soil humic materials.
AFLATOXIN G1UPTAKE BY CELLS OF FLAVOBACTERIUM AURANTIACUM
Authors: Lillehoj E. B. , Ciegler A. , Hall H. H.
Published: February 2010

Aflatoxin G1was removed from liquid cultures by growing and resting cells of Flavobacterium aurantiacum NRRL B-184. In inoculated culture media containing toxin levels of 7.5 p.p.m. and above, there was a protracted growth lag which was subsequently overcome; toxin removal then occurred, concomitant with growth. Only a few cells demonstrated aberrant morphological forms when cultured in the presence of aflatoxin G1. A comparison of the effects of aflatoxin G1with B1on growth and morphology showed that B1was distinctly more toxic. Three hundred and thirty micrograms of aflatoxin G1was removed per 1 × 1013resting cells during a 4-hour incubation period. Preincubation of resting cells with aflatoxin B1did not interfere with subsequent uptake of G1.
THE EFFECT OF SOME CULTURAL CONDITIONS ON THE ARYLSULFATASE OF PROTEUS RETTGERI
Authors: Milazzo F. H. , Fitzgerald J. W.
Published: February 2010

The influence of temperature, pH, and sulfur source on arylsulfatase formation in P. rettgeri was investigated. The highest level of enzyme activity was found when the organism was grown at 28 °C in a glycerol–salts medium (pH 7.0) containing 2.7 mM methionine. Low levels of enzyme activity were found when the organism was grown in the presence of 0.8 and 1.5 mM sulfate but 3.0 and 9.0 mM sulfate repressed enzyme formation.Conditions optimal for the formation of enzyme active against p-nitrophenol sulfate were not identical with those optimal for formation of enzyme active against nitrocatechol sulfate.The findings of this work are compared to similar findings in other bacterial systems.
COMPARISON OF VIABILITY OF STRAINS OF NEUROSPORA AFTER STORAGE IN LIQUID NITROGEN
Authors: Wellman A. M.
Published: February 2010

The survival of mutant and wild type macroconidia of Neurospora was compared after the conida, in the "air dry" state, had been frozen rapidly to −196 °C in liquid nitrogen and thawed rapidly. The 16 isolates of Neurospora were compared after 3 months' storage in liquid nitrogen with 7-day-old control cultures. Eleven of the 16 isolates showed no significant difference from 7-day-old controls in the pattern of germination after 8 hours' incubation. In the remainder, those spores germinating did so at a rate comparable to that of the controls, but the final proportion germinating was 5.0–19.0% lower.
DISSOCIATION OF ESTERASE FROM PROTEINASE ACTIVITY OF BACILLUS SUBTILIS SPORES
Authors: Sierra Gonzalo
Published: February 2010

Preparations of ballistically disintegrated Bacillus subtilis spores have been shown to possess proteinase in addition to esterase activities. Both proteinase and esterase activities have been suggested as trigger for the initiation of germination, but information on these two activities in bacterial endospores is scant. Since some proteinases catalyze the hydrolysis of esters, there exists a possible identity of some esterases with proteinases. To get information on the esterase and proteinase activities of B. subtilis spores, the sensitivity to heat and to inhibitors was explored. The thermal effect and the effect of certain inhibitors on esterase activities towards several esters suggested that an unspecific esterase was responsible for these activities.Differential effects of heat, pH, and inhibitors on esterase and proteinase activities indicated the dual nature of these two activities. In absence of convincing experimental evidence to the contrary, the present indication seems to be that the esterase activities observed in B. subtilis spores were dissociated from the activity which hydrolyzes casein. The esterase activity was readily inhibited by diethyl p-nitrophenyl phosphate, diisopropylphosphofluoridate, eserine, sodium fluoride, and Zn ions, and possessed properties of a B-esterase. The proteinase activity was inhibited only by diisopropylphosphofluoridate showing properties, so far studied, similar to subtilopeptidase.