bluuebunny/crossref_metadata_2025 huggingface dataset:
Acetylene reduction (nitrogen fixation) associated with corn inoculated with Spirillum
Authors: Barber L E , Tjepkema J D , Russell S A , Evans H J
Published: January 2020

Sorghum and corn breeding lines were grown in soil in field and greenhouse experiments with and without an inoculum of N2-fixing in Spirillum strains from Brazil. Estimated rates of N2 fixation associated with field-grown corn and sorghum plants were less than 4 g of N2/ha per day. The mean estimated N2-fixation rates determined on segments of roots from corn inoculated with Spirillum and grown in the greenhouse at 24 to 27 degrees C were 15 g of N2/ha per day (16 inbreds), 25 g of N2/ha per day (six hybrids), and 165 g of N2/ha per day for one hybird which was heavily inoculated. The corresponding mean rates determined from measurements of in situ cultures of the same series of corn plants (i.e., 16 inbreds, six hybrids, and one heavily inoculated hybrid) were 0.4, 2.3, and 1.1 g of N2/ha per day, respectively. Lower rates of C2H2 reduction were associated with control corn cultures which had been treated with autoclaved Spirillum than with cultures inoculated with live Spirillum. No C2H2 reduction was detected in plant cultures treated with ammonium nitrate. Numbers of nitrogen-fixing bacteria on excised roots of corn plants increased an average of about 30-fold during an overnight preincubation period, and as a result acetylene reduction assays of root samples after preincubation failed to serve as a valid basis for estimating N2 fixation by corn in pot cultures. Plants grown without added nitrogen either with or without inoculum exhibited severe symptoms of nitrogen deficiency and in most cases produced significantly less dry weight than those supplied with fixed nitrogen. Although substantial rates of C2H2 reduction by excised corn roots were observed after preincubation under limited oxygen, the yield and nitrogen content of inoculated plants and the C2H2-reduction rates by inoculated pot cultures of corn, in situ, provided no evidence of appreciable N2 fixation.
Types of respiratory activity in Moniliella tomentosa during growth under different conditions
Authors: Hanssens L , Verachtert H
Published: January 2020

The osmophilic yeastlike fungus Moniliella tomentosa is an obligate aerobe and is not susceptible to glucose repression. Respiration is greatest in exponentially growing cells and is then highly sensitive to cyanide. Respiration in older cells or in chloramphenicol-grown cells is mediated by a cyanide-insensitive respiration which is sensitive to salicyl hydroxamic acid. Growth of cells under reduced oxygen does not influence the respiratory capacity of the cells but results in a longer generation time and a lower final cell yield. Low aeration levels and growth in the presence of chloramphenicol have a profound effect on ethanol and polyol production.
Viscous Product from Activated Sludge by Methanol Fermentation
Authors: Davis Edwin N. , Wallen Lowell L.
Published: January 2020

Aeration of activated sludge with 3 to 4% added methanol for 5 to 7 days yields an odorless, highly viscous (5,000 to 10,000 centipoise), black, pudding-like product containing glycan(s) linked other than α-1-4 or β-1-3. Backseeding gives maximum thickening in 3 to 4 days. Incomplete acid hydrolysis of the black product gives a 0.27% solution of reducing sugars (75% glucose) which is an 11.4% yield from the added methanol. Backseeding into either centrifuge supernatant or 0.1% yeast extract in tap water gives a light-colored polymer. Viscosity decreases during extended sterile cold storage. A 5% salt addition lowers viscosity one-half. From 6 to 12 colony types appear on plating backseeded media, but none of these isolates is a reliable polymer former.
Urease assay and urease-producing species of anaerobes in the bovine rumen and human feces
Authors: Wozny M A , Bryant M P , Holdeman L V , Moore W E
Published: January 2020

A growth medium and test were developed for rapid detection of urease in fermentative anaerobic bacteria. Using nonselective rumen fluid roll-tube agar medium and the new test, it was confirmed that Peptostreptococcus productus is often the most numerous urease-forming species in human feces. Also, some fecal strains of Ruminococcus albus, Clostridium innocuum, and Clostridium beijerinckii produced urease. Single strains of Fusobacterium prausnitzii, Coprococcus catus, and Streptococcus mitis that were strongly ureolytic on isolation later lost this ability. Urease activity was also detected in many strains of nonselectively isolated rumen species. They include Succinivibrio dextrinosolvens, Treponema sp., Ruminococcus bromii (not previously known to be present in the rumen), Butyrivibrio sp., Bifidobacterium sp., Bacteroides ruminicola, and P. productus. Most P. productus strains contain urease; however, the uniformity of this feature in the other species noted above is not known. The urease in many of these species was not detected if the growth medium contained 0.2% or more (each) yeast extract and Trypticase.
Effect of combined heat and radiation on microbial destruction
Authors: Fisher D A , Pflug I J
Published: January 2020

A series of experiments at several levels of relative humidity and radiation dose rates was carried out using spores of Bacillus subtilis var. niger to evaluate the effect of heat alone, radiation alone, and a combination of heat and radiation. Combined heat and radiation treatment of microorganisms yields a destruction rate greater than the additive rates of the independence agents. The synergistic mechanism shows a proportional dependency on radiation dose rate an Arrhenius dependency on temperature, and a dependency on relative humidity. Maximum synergism occurs under conditions where heat and radiation individually destroy microorganisms at approximately equal rates. Larger synergistic advantage is possible at low relative humidities rather than at high relative humidities.
Distribution of bacteria with nitrilotriacetate-degrading potential in an estuarine environment
Authors: Bourquin A W , Przybyszewski V A
Published: January 2020

Attempts to isolate estaurine bacteria capable of metabolizing nitrilotriacetate (NTA) as a sole carbon source from areas within Escambia Bay, Fla., were unsuccessful; however, bacteria from freshwater streams and from estaurine surface microlayers were easily adapted to degradation of NTA in freshwater medium. A Pseudomonas sp. strain (ATCC 29600), capable of growth on NTA as a sole carbon source, metabolized NTA at a reduced rate in a saline medium (15%), compared with a freshwater medium (0 to 15%). Microorganisms capable of degrading NTA exist in estuarine surface microlayers and in fresh subsurface waters just before entering the estuary; these data indicate an interference with NTA catabolism by some unknown factors of the estuarine environment rather than an absence of potential NTA-degrading bacteria.
Limitations of lysine-iron-cystine-neutral red broth in the presumptive identification of Salmonella
Authors: D'Aoust J Y
Published: January 2020

Lysine-iron-cystine-neutral red broth performed satisfactorily in the presumptive identification of Salmonella in preenriched food and animal feed samples enriched in tetrathionate-brilliant green broth. Homologous results from selenite-cystine enrichment broths yielded unacceptably high numbers of false negative reactions.
Isolation of bacteriophage 14-lysogenized Salmonella from the freshwater aquarium snail Apullaria
Authors: Bartlett K H , Trust T J , Lior H
Published: January 2020

A naturally occurring Salmonella mikawasima serologically converted by phage 14 (6,7,14:y:e,n,z15) has been isolated for the first time. An S. tennessee variant seroconverted by phage 14 (6,7,14:z29:-) was also isolated. The source of these salmonellae was the common freshwater aquarium snail Ampullaria. Phage 14 prepared from these serovariants was lytic for S. bovis-morbificans (6,8:r:1,5) and for S. hadar (6,8:z10:e,n,x).
Respiration Correction for Microbial Heterotrophic Activity Assays That Use Tritium-Labeled Substrates
Authors: Dietz Allan S. , Albright Lawrence J.
Published: January 2020

Filtrates from microbial heterotrophic activity assay experiments in which tritiated glucose was used as a radioactively labeled substrate were collected, and their radioactivities were determined. These filtrates were subsequently evaporated to dryness to remove tritiated water generated by metabolism of the labeled glucose; the residue was suspended to original volume with distilled water, and the tritium levels were again assayed. In the water samples assayed, the amount of tritium label retained by the microorganism was about 75% of that respired.
Simple bacterial preservation medium and its application to proficiency testing in water bacteriology
Authors: Brodsky M H , Ciebin B W , Schiemann D A
Published: January 2020

A medium composed of nutrient broth, 1.8% boric acid, and 1% sodium chloride at pH 7.0 was shown to maintain the stability of Escherichia coli cultures for up to 10 days at room temperature. By using this preservation medium for preparing a simulated sample a successful proficiency test survey in water bacteriology was conducted.
New modification of Willis and Hobbs' method for identification of Clostridium perfringens
Authors: Serrano A M , Schneider I S
Published: January 2020

A modification of the medium of Willis and Hobbs is described. All strains of Clostridium perfringens grown on it gave a positive lecithinase reaction. Some gave a negative reaction in the origin medium.
Safe, convenient, portable pipettor
Authors: Songer J R
Published: January 2020

A dafe, convenient, portable pipetting device that will accommodate any size pipette is described. A vacuum bulb eliminates the need for external vacuum. Necessary components, fabrication procedures, and operating techniques are given.
Analysis of deoxynivalenol from cultures of Fusarium species
Authors: Pathre S V , Mirocha C J
Published: January 2020

Eight isolates of Fusarium roseum and three of Fusarium colmorum were found to produce deoxynivalenol in rice cultures. Deoxynivalenol was extracted with aqueous methanol (40%) and purified by partitioning with ethyl acetate and acetonitrile-petroleum ether (boiling point, 60--70 degrees C). The toxin was identified by gas chromatography/mass spectrometry and quantified by gas-liquid chromatography. High recoveries (80%) of deoxynivalenol were obtained from rice cultures, and as low as 0.250 microgram of the toxin per g was detected.
Survival of a Salmonella typhimurium experimental contaminant during cooking of beef roasts
Authors: Blankenship L C
Published: January 2020

Twenty-one raw boneless beef roasts were experimentally injected with 2 X 10(7) cells of a nalidixic acid-resistant strain of Salmonella typhimurium per roast. Contaminated roasts were cooked to center internal temperatures of 137.0 to 147.5 degrees F (58.3 to 64.1 degrees C) in a gas-fired pilot plant food-processing oven. Viable experimental contaminants were recovered from two core samples of the 21 roasts (one cooked to 137.0 degrees F [58.3 degrees C] and one cooked to 141.5 degrees F [ca 60.8 degrees C]). All of 17 cooking net samples taken from the contaminant injection side of roasts were salmonella positive, whereas 7 of 9 net samples from the side opposite injection were positive and all of 11 net samples from the bottom of roasts were positive. The implications of these results are discussed in relation to salmonella contamination of precooked beef roasts.
Poliovirus removal from primary and secondary sewage effluent by soil filtration
Authors: Gerba C P , Lance J C
Published: January 2020

Adsorption of poliovirus from primary sewage effluent was similar to that from secondary sewage effluent in both batch soil studies and experiments with soil columns 240 cm long. Virus desorption by distilled water was also similar in a soil column that had been flooded with either primary or secondary effluent seeded with virus. These results indicated that absorption of poliovirus from primary effluent and virus movement through the soil were not affected by the higher organic content of primary sewage effluent.
Stabilization of Lactose Metabolism in
Streptococcus lactis
C2
Authors: McKay L. L. , Baldwin K. A.
Published: January 2020

The integration of the lactose plasmid from lactic streptococci into the host chromosome could stabilize this trait for dairy fermentations. Sixty lactose-positive (Lac
+
) transductants of lactose- and proteinase-negative (Lac
−
Prt
−
) LM0220 were induced for temperature phage by UV irradiation or mitomycin C. Four of the transductants, designated KB18, KB21, KB54, and KB58, yielded lysates demonstrating less than one Lac
+
transductant per 0.2 ml of phage lysate. Successive transferring in the presence of acriflavine did not yield Lac
−
segregants from KB18, KB21, KB54, or KB58, whereas
Streptococcus lactis
C2 (parent culture) and three other Lac
+
transductants showed 12 to 88% conversion from Lac
+
to Lac
−
within 6 to 10 repetitive transfers. When grown in continuous culture, KB21 did not show any Lac
−
variants in 168 h, while
S. lactis
C2 had 96% conversion from Lac
+
to Lac
−
in 144 h. Agarose gel electrophoresis of plasmid DNA isolated from KB18, KB21, KB54, and KB58 revealed that the lactose plasmid, pLM2103, normally present in Lac
+
transductants, was missing. This suggested integration of the transferred lactose plasmid into the chromosome. In contrast to phage lysates induced from
S. lactis
C2, which exhibited an exponential decrease in the number of Lac
+
transductants after exposure to small doses of UV irradiation, the transduction frequency for lactose metabolism was stimulated by UV irradiation of lysates from KB58. The latter indicated chromosomal linkage for
lac
and that integration of the lactose genes plasmid into the chromosome had occurred.
Dry-heat destruction of lipopolysaccharide: dry-heat destruction kinetics
Authors: Tsuji K , Harrison S J
Published: January 2020

Dry-heat destruction kinetics of lipopolysaccharides from Escherichia coli, Serratia marcescens, and Salmonella typhosa at 170 to 250 degrees C are described. The destruction rate seems to follow the second order and can be linearized by the equation, log y = a + b . -10cx. Because c is the slope, 1/c = D3. Both a and b are constant at a given temperature and are linear functions of temperature. The D(3)170, D(3)190, D(3)210, D(3)230, and D(3)250 values for E. coli lipopolysaccharide are 251, 99.4, 33.3, 12.3, and 4.99 min, respectively, with a z value of 46.4 min. The D values for lipopolysaccharides from S. marcescens and S. typhosa are not significantly different from those from E. coli lipopolysaccharide.
Isolation and identification of the cytoplasmic membrane from Saccharomyces carlsbergensis by radioactive labeling
Authors: Lewis M J , Patel P C
Published: January 2020

The cytoplasmic membrane of Saccharomyces carlsbergensis was isolated by enzymatic digestion of the yeast cell wall, followed by lysis of the protoplasts and fractionation by ultracentrifugation in a discontinuous sucrose density gradient. Location of the cytoplasmic membrane fraction on the sucrose gradient was made by labeling intact protoplasts with [G-3H]dansyl chloride, and was settled at the 50% (wt/vol) sucrose gradient (d = 1.186 g/cm3). Approximately 80% of the radioactivity was found in the membrane fraction prepared in the presence of Mg2+ ions. However, when protease inhibitors were used in the preparation step, the membrane fraction contained over 90% of the total radioactivity. The presence of Mg2+ ions during membrane isolation and purification enhanced the aggregation of membrane components but, at higher concentrations, as well as in the prolonged presence of Mg2+ ions in the membrane suspension, it caused the breakdown of membrane components. The membrane preparation contained Mg2+-adenosine triphosphatase, which was insensitive to oligomycin and ouabain. The distribution of Mg2+-adenosine triphosphatase in different fractions during sucrose gradient is reported.
Nonlogarithmic death rate calculations for Byssochlamys fulva and other microorganisms
Authors: King A D , Bayne H G , Alderton G
Published: January 2020

Survivor curves for heat-resistant ascospores of Byssochlamys fulva exposed to lethal heat were nonlogarithmic. At lower heating temperatures, the log survivor curves were characterized by a shoulder plus an accelerating death rate; with increased temperatures, the rate approached logarithmic death. The formula (log No -- log N)a = kt + C was adapted to linearize these data. No and N are the initial and surviving numbers of organisms at the time t. The death rate is given by k, and C is a constant for a set of data. The a value is derived from the least-squares slope of a plot of log (log No -- log N) against log time and is used to linearize the thermal death rate curves. This formula permitted calculations of parameters analogous to those for logarithmic death (D and z). Use of formula is illustrated for selected nonlinear microbial death rate curves from the literature.
Attachment to Autoclaved Soil of Bacterial Cells from Pure Cultures of Soil Isolates
Authors: Balkwill D. L. , Casida L. E.
Published: January 2020

Pure cultures of
Arthrobacter globiformis
and four fresh soil isolates were incubated individually in autoclaved soil, in both the presence and absence of glucose. These bacteria grew in the soil and, except for
A. globiformis,
eventually attached firmly to the soil solids. Firmly attached cells were defined as those which could not be separated from the soil solids by blending combined with a series of low-speed centrifugal washings. The attachment attained by the soil isolates appeared to duplicate that of the overall bacterial population that resides naturally in unaltered, unamended soil. Cell attachment in the autoclaved-soil system was accelerated slightly by glucose, but, except for one soil isolate, several months of incubation were still required before firm attachment was complete. Electron microscopy indicated that all attached cells produced extracellular polysaccharide slimes in the autoclaved soil and that these materials appeared to connect the cells to surrounding pieces of soil debris. The actual role of polysaccharides in attachment was not clear, however, because at least one of these organisms possessed extracellular slime during the long period in which it had not yet attached to the soil.
Effect of SO2 and bisulfite on heterotrophic activity in an acid soil
Authors: Grant I F , Bancroft K , Alexander M
Published: January 2020

Glucose oxidation was inhibited in a forest soil (pH 4.01) previously exposed by 1.0 microliter of SO2 per liter, the extent of inhibition and the decline in pH being directly related to the length of exposure. The phase of rapid CO2 evolution in protein hydrolysate-amended soil previously treated with 5.0 microliter of SO2 per liter for 24 h or 1.0 microliter/liter for 48 h was delayed, but the degradation of the amino acid mixture then proceeded rapidly. Bacterial numbers in soil incubated for 48 h with 1.0 microliter of SO2 per liter were reduced, but the bacteria grew rapidly if glucose or an amino acid mixture was added after the exposure period. Low levels of bisulfite inhibited amino acid decomposition in soil at pH 3.89, but the effect was less pronounced in soil at pH 4.01. Comparable levels of sulfate were not toxic to carbon mineralization. Approximately 1.0 microgram of bisulfite S and about 20 microgram of sulfate S per g of soil appeared when the soil was treated with 1.0 microliter of SO2 per liter for 48 h. Bisulfite added to the soil disappeared readily. The possible ecological significance of the findings is discussed.
Specificity of bacteriolytic enzyme II from a soil amoeba, Hartmannella glebae
Authors: Hemelt D M , Mares B , Upadhyay J M
Published: January 2020

Two bacteriolytic enzymes were produced when Hartmanella glebae was grown in the presence of both Enterobacter aerogenes and Alcaligenes faecalis. The identification of enzyme I as N-acetylmuramidase was reported earlier. Enzyme II was purified by gel filtration on a Bio-Gel A column. A recovery of 68.76% with 72.3-fold purification was obtained. It was found that 5 and 10 mM MgCl2 significantly increased the bacteriolytic activity. It is a basic protein. The cell walls of Micrococcus lysodeikticus were lysed by the enzyme, and the products of digestion were purified by Amberlite CG-120 and Sephadex G-15 chromatography to facilitate the detection of amino sugars. After reduction of the oligosaccharides with sodium borohydride and acid hydrolysis, the amino sugars were identified by paper chromatography. It was found that enzyme II cleaved the glycosidic bond between N-acetylmuramic and and N-acetylglucosamine of the peptidoglycan moiety of the cell walls. Thus, the enzyme was identified as endo-beta-N-acetylmuramidase.
Wipe-rinse technique for quantitating microbial contamination on large surfaces
Authors: Kirschner L E , Puleo J R
Published: January 2020

The evaluation of an improved wipe-rinse technique for the bioassay of large areas was undertaken due to inherent inadequacies in the cotton swab-rinse technique to which assay of spacecraft is currently restricted. Four types of contamination control cloths were initially tested. A polyester-bonded cloth (PBC) was selected for further evaluation because of its superior efficiency and handling characteristics. Results from comparative tests with PBC and cotton swabs on simulated spacecraft surfaces indicated a significantly higher recovery efficiency for the PBC than for the cotton (90.4 versus 75.2%). Of the sampling areas sites studied, PBC was found to be most effective on surface areas not exceeding 0.74 m2 (8.0 feet 2).
Toxicity of parasporal crystals of Bacillus thuringiensis subsp. israelensis to mosquitoes
Authors: Tyrell D J , Davidson L I , Bulla L A , Ramoska W A
Published: January 2020

Toxicity of Bacillus thuringiensis subsp. israelensis (ONR-60A/WHO 1897) parasporal crystals to three medically important mosquito larvae is described. The numbers of larvae killed are in relation to crystal dry weight. The crystals are lethally toxic to Aedes aegypti Linnaeus (mean 50% lethal concentration [LC50] = 1.9 x 10(-4) micrograms/ml), Culex pipiens var. quinquefasciatus Say (LC50 = 3.7 x 10(-4) micrograms/ml), and Anopheles albimanus Wiedemann (LC50 = 8.0 x 10(-3) micrograms/ml). Purfied crystals of B. thuringiensis subsp. kurstaki, which are toxic to lepidopteran insects, are ineffective against the mosquito larvae. Likewise, B. thuringiensis subsp. israelensis parasporal crystals are not efficacious for larvae of the lepidopteran, Manduca sexta.
Maceration of Clover and Grass Leaves by
Lachnospira multiparus
Authors: Cheng K.-J. , Dinsdale D. , Stewart C. S.
Published: January 2020

A strain of
Lachnospira multiparus
, a pectin-hydrolyzing bacterium from the rumen, was incubated in nutrient media in the presence of surface-disinfected clover leaflets. When the culture flasks containing the leaflets together with
Lachnospira
were shaken after overnight incubation, extensive maceration of the leaflets was seen, although uninoculated control leaflets remained intact during a similar treatment. Examination of inoculated leaflets by transmission electron microscopy showed extensive invasion of intercellular areas of the mesophyll tissue but only minor invasion of vascular tissue. Cutting the leaves before incubation greatly increased the ability of
L. multiparus
to colonize and macerate the leaflets. Similar experiments with grass leaves are also described, and the possible role of maceration in the digestion of plant material in the rumen is discussed. Although
Lachnospira
stains gram variable and often gram negative, the ultrastructure of the cell wall was that of a gram-positive bacterium.
Effect of processing variables on the outgrowth of Clostridium sporogenes PA 3679 spores in comminuted meat cured with sorbic acid and sodium nitrite
Authors: Robach M C
Published: January 2020

The effects of the initial pH and a "short pump" on the outgrowth of Clostridium sporogenes PA 3679 spores in comminuted cured pork were studied. Fresh ground pork was cured with salt, sugar, phosphate, ascorbate, and varying amounts of sodium nitrite and sorbic acid. The product was comminuted and inoculated with 1,000 spores of C. sporogenes per g. The meat was stuffed into 1-ounce (ca. 28.4-g) aluminum tubes, cooked to 58.5 degrees C, cooled, and incubated at 27 degrees C to observe for swells. Product cured with 0.2% sorbic acid in combination with 40 ppm sodium nitrite (40 microgram/g) had better clostridium inhibition than did product cured with 120 ppm nitrite within a pH range of 5.0 to 6.7. The sorbic acid-40 ppm nitrite combination also gave better clostridial protection than did the 120 ppm nitrite alone when reduced amounts of curing ingredients were present.
Determining endotoxin content of ground beef by the Limulus amoebocyte lysate test as a rapid indicator of microbial quality
Authors: Jay J M , Margitic S , Shereda A L , Covington H V
Published: January 2020

Eighty-four samples of ground beef were placed into five half-log cycle groups based upon aerobic plate count (APC) results. Endotoxins were determined by the Limulus amoebocyte lysate test (LAL), and gram-negative viable counts were determined by a violet red bile agar overlay method. Ten samples with a log of APC of less than 5.50 had an APC mean of less than 5.24 and mean endotoxin content by the LAL of 51 ng/g. The 15 samples with APCs between a log of 5.50 and 5.99 had an APC mean of 5.79/g and an endotoxin mean of 103.8 ng/g. Twenty-eight samples had APCs between a log of 6.00 and 6.49 with a mean of 5.28/g and an endotoxin mean of 1106.4 ng/g. The 20 samples with APCs between a log of 6.50 and 7.00 had a mean of 6.77/g and an endotoxin mean of 5067.6 ng/g, while 11 samples had a log of APCs of greater than 7.00 with a mean of 7.53 and an endotoxin mean of 7,472 ng/g. Correlation of half-log cycle mean APC and violet red bile agar counts with mean endotoxin content were both highly significant, indicating that LAL-determined endotoxin content can be used to make a rapid approximation of viable plate counts. Because results can be obtained by LAL in 1 h, the finding of low levels of endotoxins can be taken to indicate low-count meat. The use of additional tests of microbial quality may be necessary when high endotoxin levels are found because the LAL detects both viable and nonviable cells.
Evaluation of a class III biological safety cabinet for enclosure of an ultracentrifuge
Authors: Chatigny M A , Dunn S , Ishimaru K , Eagleson J A , Prusiner S B
Published: January 2020

An evaluation of a special safety cabinet housing a high-speed centrifuge was made. The cabinet enclosed both the top access port and the drive and pumping machinery of the centrifuge. A titanium rotor was loaded with tubes containing a bacterial culture, weakened, and driven until rotor rupture occurred. There were several bent and broken components in the centrifuge, and bacteria leaked from the vacuum chamber. Although the forces were sufficient to displace the cabinet, none of the test bacteria were found outside the cabinet.
A Thick-Walled Organism Isolated from the Cockroach Gut by Using a Spent Medium Technique
Authors: Cruden Diana Loeb , Markovetz A. J.
Published: January 2020

By using a conditioning technique whereby complex media are inoculated several times with bacteria from the hindgut of the cockroach
Eublaberus posticus
, a succession of bacterial types occurred. An obligately anaerobic, pleomorphic, thick-walled, gram-positive organism is described which was isolated by this culturing technique.
Enrichment and Association of Bacteria and Particulates in Salt Marsh Surface Water
Authors: Harvey R. W. , Young L. Y.
Published: January 2020

Elevated counts of bacteria were found during outgoing tides in surface microlayers (∼300 μm) of Sippewissett salt marsh, Falmouth, Massachusetts, and Palo Alto salt marsh, Palo Alto, California. At both sampling sites, the degrees by which bacteria were concentrated into the surface microlayer were linearly dependent upon surface concentration of particulate material. A significant percentage of bacteria in the microlayer were found to be attached to particulate material, while bacterial populations in the subsurface water were largely planktonic. Proportions of the bacterial populations which could be grown on seawater nutrient agar were also greater in the microlayer than in the subsurface waters and were positively correlated with the fraction of bacteria attached to particulate matter. Data from these studies suggest that particulates in the microlayer waters of the salt marsh influenced the observed increase in both the readily grown and the total numbers of bacteria.
Toxic Effect of Cysteine Against
Salmonella typhimurium
Authors: Gomez Reinaldo F. , Montville Thomas , Blais Kendrick
Published: January 2020

Cysteine was shown to be toxic to
Salmonella typhimurium
. The mechanism of this toxicity may be due, at least in part, to cysteine's ability to cause deoxyribonucleic acid strand scissions.
Fermentation of polysaccharides by Klebsielleae and other facultative bacilli
Authors: Ochuba G U , von Riesen V L
Published: January 2020

Fermentations of 10 polysaccharides by species of the family Enterobacteriaceae were examined. Algin, guar, karaya, xanthan, and xylan were not fermented by any of the strains tested. Most of the activity was found in the tribe Klebsielleae. Klebsiella oxytoca fermented amylopectin (97% of the strains studied), carrageenan (100%), inulin (68%), polypectate (100%), and tragacanth (100%). Klebsiella pneumoniae fermented amylopectin (91%), carrageenan (100%), and tragacanth (86%). Carrageenan was also fermented by Enterobacter aerogenes (100%), Enterobacter agglomerans (63%), Enterobacter cloacae (95%), and Pectobacterium (38%). Pectobacterium shared polypectate fermentation (100%) with K. oxytoca. With one exception, Serratia strains were negative on all polysaccharides. These results, along with other evidence, indicate that (i) the genus Klebsiella is biochemically the most versatile genus of the tribe, (ii) because of its distinct characteristics, K. oxytoca warrants species designation separate from K. pneumoniae, and (iii) some food additives generally considered indigestible can be metabolized by a few species of facultative bacilli, whereas others appear to be resistant.
Antibotulinal efficacy of sulfur dioxide in meat
Authors: Tompkin R B , Christiansen L N , Shaparis A B
Published: January 2020

The addition of sodium metabisulfite as a source of sulfur dioxide delayed botulinal outgrowth in perishable canned comminuted pork when it was temperature abused at 27 degree C. The degree of inhibition was directly related to the level of sulfur dioxide. Levels greater than 100 microgram of sulfur dioxide per g were necessary to achieve significant inhibition when a target level of 100 botulinal spores per g was used. Sodium nitrite partially reduced the efficacy of the sulfur dioxide. Sulfur dioxide offers a new option for the control of botulinal outgrowth in cured or noncured meat and poultry products.
Inhibition of nitrate reduction in some rumen bacteria by tungstate
Authors: Prins R A , Cliné-Theil W , Malestein A , Counotte G H
Published: January 2020

Tungstate prevented the formation of active nitrate reductase in growing rumen bacteria capable of nitrate reduction, but did not directly inhibit the enzyme activity of all strains tested.
Bacterial effect of hydrogen peroxide on urinary tract pathogens
Authors: Schaeffer A J , Jones J M , Amundsen S K
Published: January 2020

Bacterial contamination of urinary drainage bags is a frequent source of bladder bacteriuria in patients with indwelling catheters. Previous work demonstrated that the addition of 30 ml of 3% H2O2 prevented bacterial contamination of urinary drainage bags for up to 8 h in patients with urinary infections (greater than 10(5) colony-forming units per ml). Survival curves of a variety of organisms in filter-sterilized urine with various concentrations of H2O2 (0.6 to 0.01%) were constructed. Organisms with high cellular catalase activity (Staphylococcus aureus, Serratia marcescens, and Proteus mirabilis) required 30 to 60 min of exposure to 0.6% H2O2 for a reduction of 10(8) to less than 1 colony-forming unit per ml, whereas Escherichia coli, Streptococcus sp., and Pseudomonas sp. required only 15 min of exposure. The efficacy of H2O2 in urine was maintained despite exposure to room temperature for 5 days and reinoculation with bacterial suspensions. H2O2 is inexpensive and relatively nontoxic, and these data suggest that periodic instillation of H2O2 into urinary drainage bags may eliminate a source of bladder bacteriuria and environmental contamination.
Cell envelope damage in Escherichia coli caused by short-term stress in water
Authors: Zaske S K , Dockins W S , McFeters G A
Published: January 2020

Physiological and morphological changes in Escherichia coli exposed to oligotrophic natural waters and reagent grade water were studied. Several lines of evidence indicated that short-term exposure in water causes cellular envelope damage. Increasing susceptibility to lysozyme, lag time before cell division, and injury as defined by differential counts on selective and nonselective media occurred with exposure time. Electron micrographs of injured cells showed morphological changes in cell envelope.
Distribution of citrate utilization plasmids in Salmonella strains of bovine origin in Japan
Authors: Ishiguro N , Hirose K , Sato G
Published: January 2020

Attempts to detect transferable citrate-utilizing (Cit) ability in enterobacterial strains were carried out by conjugation experiments. Of 318 strains of Salmonella typhimurium and 1 strain of Salmonella bredeney isolated from cattle in Japan from 1970 to 1979, 107 (33.5%) strains contained transferable Cit characters. Most of the strains transferred the Cit characters to recipient Escherichia coli more efficiently at 28 degrees C than at 37 degrees C, indicating that their transfer of the Cit character is thermosensitive. Transferred Cit characters were found in association with drug resistance markers such as ampicillin, chloramphenicol, kanamycin, streptomycin, sulfonamides, and tetracycline or with mercury resistance, but Cit plasmids conferring Cit ability alone were also obtained. Of 221 conjugative Cit plasmids tested for fertility inhibition (Fi), all but 2 were Fi- and exhibited thermosensitive transfer; 2 Cit plasmids showing the Fi+ character were also isolated from 2 S. typhimurium strains. No transferable Cit character was detected from strains of Proteus, Serratia, Klebsiella, Enterobacter, and Citrobacter spp. isolated from humans or cows in the present study. The utilization of tricarboxylic acids by strains with plasmid-borne Cit ability was examined, and two different patterns of utilization were found in the Cit+ E. coli transconjugants.
Biosynthesis of versicolorin A
Authors: Anderson M S , Dutton M F
Published: January 2020

The incorporation of various potential intermediates into versicolorin A by a versicolorin A-accumulating mutant of Aspergillus parasiticus was studied. Both whole mycelium and cell-free extracts of this mutant were able to convert 14C-labeled versiconal hemiacetal acetate to versicolorin A. By the use of a labeled double substrate technique it was shown that two other compounds, versicolorin A hemiacetal and its acetate derivative, were also converted to versicolorin A. It is concluded that one or both of these compounds are intermediates in the biosynthesis of versicolorin A and therefore may possibly be involved in the biogenesis of the aflatoxins.
Delayed secondary enrichment for the isolation of salmonellae from broiler chickens and their environment
Authors: Rigby C E , Pettit J R
Published: January 2020

Specimens collected from six broiler flocks were cultured for salmonellae by three methods. (i) For direct enrichment, the specimen was homogenized, and 1 ml of the homogenate was inoculated into tetrathionate-brillant green broth; (ii) for preenrichment, liquid specimens and homogenates were incubated at 37 degrees C, and on the next day 1 ml was inoculated into tetrathionate-brillant green broth; and (iii) for delayed secondary enrichment, incubated preenrichment cultures were held at room temperature for 7 to 10 days and then subcultured to fresh tetrathionate-brilliant green broth. All tetrathionate-brilliant green broth cultures were incubated at 42 degrees C for 24 to 48 h before plating. Significantly more isolations of salmonellae were obtained by delayed secondary enrichment than by direct enrichment or preenrichment. Salmonellae were isolated from 417 of 2,283 (18.3%) samples of litter, intestinal contents, and feces cultured by all three methods. Of these positive specimens, direct enrichment detected 208 (49.9%), preenrichment detected 282 (67.6%), and delayed secondary enrichment detected 373 (89.4%). Of 896 specimens of swabs and rinse fluids that were cultured by preenrichment and delayed secondary enrichment, 259 (28.9%) yielded salmonellae. Delayed secondary enrichment detected 254 (98.1%) of these, and preenrichment detected 147 (56.8%). A total of 23 serotypes of salmonellae were identified. The greater effectiveness of delayed secondary enrichment for the isolation of salmonellae was not likely due to the selection of certain serotypes or to an increased inhibition of competing flora.
Problems encountered with the capillary tube immunodiffusion method for detection of botulinal toxin
Authors: Guilfoyle D E , Mestrandrea L W
Published: January 2020

By using antitoxin specific for the neurotoxin molecule, the capillary tube immunodiffusion method did not detect low levels of crystalline toxin. Reactions described earlier with crude toxin and less specific antitoxin were probably due to nontoxigenic botulinal antigens.
Diversity and Dynamics of Indigenous
Rhizobium japonicum
Populations
Authors: Noel K. Dale , Brill Winston J.
Published: January 2020

A simple method, based upon the separation of cellular proteins by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis, has been devised for distinguishing between isolates of
Rhizobium japonicum
. Eleven laboratory strains, previously classified into five serogroups, were analyzed by gel electrophoresis. Groups determined subjectively according to protein patterns matched the serogroups, with one exception. Most strains within serogroups could be distinguished from one another. For studying the ecology of
Rhizobium
, an important advantage of this technique compared with serology or phage typing is that it discriminates among previously unencountered indigenous bacterial isolates as well as among known laboratory strains. SDS-gels were used to analyze the
Rhizobium
population of 500 nodules, sampled throughout the growing season, from soybeans at two different Wisconsin localities. Although the soybeans had been inoculated with laboratory strains of
R. japonicum
, indigenous
R. japonicum
predominated. At one location, 19 indigenous gel types were distinguished and classified mainly into four groups. At the other location, 18 gel types, falling mainly into three groups, were detected. The predominance of a particular group varied, in some cases dramatically, depending upon the time and depth of nodule formation.
Rate of occurrence of false-positive results from total coliform most-probable-number analysis of shellfish and estuaries
Authors: Hussong D , Colwell R R , Weiner R M
Published: January 2020

The incidence of confirmed test, false-positive coliform most-probable-number results was compared with environmental parameters and was found to be inversely related to water temperature. It is concluded that the completed coliform test must be done when water temperatures drop below 15 degrees C.
Distribution of Iron in
Sphaerotilus
and the Associated Inhibition
Authors: Chang Yueh , Pfeffer John T. , Chian Edward S. K.
Published: January 2020

The distribution of iron between the sheaths and the cells of iron-inhibited
Sphaerotilus
cultures was determined. The experiment was conducted with different soluble iron forms as inhibitors. The growth inhibition was found to be related to the iron sorbed by the cells rather than by the sheaths. At the 90% inhibition level, iron sorbed by the cells ranged from 13 to 15 mg/g of organism for all three inhibitors tested. For 50% inhibition, the iron sorbed by the cells ranged from 7 to 8 mg/g of organism. The iron sorbed by the sheaths varied widely, ranging from 23 to 118 mg/g of organism at the 90% inhibition level and from 11 to 61 mg/g at the 50% inhibition level. The degree of inhibition is closely related to the amount of iron sorbed by the cells, which in turn is a function of the type of iron compound or complex used. The solubility of the iron is a major consideration.
Absence of sporidesmin production by twelve Texas isolates of Pithomyces spp
Authors: Halder C A , Taber R A , Camp B J
Published: January 2020

Twelve isolates of Pithomyces spp. from Texas were tested for sporidesmin toxin production, using both high-performance and thin-layer chromatography techniques. None of the Texas isolates produced the toxin under the conditions used. A control toxigenic New Zealand isolate, Pithomyces chartarum strain C, was grown simultaneously under the conditions tested and was found to produce sporidesmin in all cases.
Sequestration of Holotrich Protozoa in the Reticulo-Rumen of Cattle
Authors: Abe Matanobu , Iriki Tsunenori , Tobe Noriko , Shibui Hitoshi
Published: January 2020

Studies were carried out to determine the means by which holotrich protozoa can maintain their numbers within the rumen against the washout effect associated with the flow of ingesta. When a diet composed of 2 kg of concentrate and 1.5 kg of rice straw was fed to Holstein cows, about a fourfold increase in holotrich numbers per ml of rumen fluid was observed within 1 h after the commencement of feeding, and an abrupt decrease followed. This fluctuation in numbers was not related to the time of feeding. A sole feeding of 2 kg of concentrate had almost the same effect on the holotrichs as a sole feeding of 1.5 kg of rice straw. Administration of either 2 kg of concentrate or 1.5 kg of rice straw through the rumen fistula caused similar changes, though the extent of response to the former was greater than that to the latter. The administration of either 0.7 kg of starch or 0.2 kg of glucose through the fistula had a relatively minor effect on the holotrich population. Addition of rice straw to 0.5 kg of concentrate increased the change in numbers, but its addition had little, if any, effect when 1 kg of concentrate was fed. These results suggested that the fluctuation in holotrich numbers was related not only to the nature or component of feed but also to other factors such as the quantity or volume of a diet and the act of ingesting feed. Increasing the number of feedings up to eight times per day at 3-h intervals caused a decrease in the peak heights of holotrich numbers per milliliter of rumen fluid. A thick protozoal mass which primarily consisted of holotrichs was found on the wall of the reticulum of Holstein steers slaughtered after overnight starvation. These findings suggest that holotrichs would usually sequester on the reticulum wall and migrate into the rumen only for a few hours after feeding, and that this mode of behavior would be essential for holotrichs to maintain their population within the rumen of cattle. Possible mechanisms of the migration are also discussed.
Immunofluorescent evidence of Proteus mirabilis swarm cell formation on sterilized rat feces
Authors: Stahl M L , Williams F D
Published: January 2020

Swarming Proteus spp. were detected with the use of proteometry (a most-probable-number technique) in the fecal material of selected animal species and in raw sewage from a local sewage treatment plant. Proteus spp. were not detected in any of several soil and freshwater samples examined. Since rat feces harbored high numbers of Proteus mirabilis compared with other habitats examined, we chose to examine it for the possibility of supporting swarming. Immunofluorescent studies with a strain-specific conjugate revealed the morphogenesis of short forms into elongated swarm cells upon the surface of sterilized rat feces that had been inoculated with short forms of P. mirabilis. the same phenomenon was not observed consistently when nonsterile rat feces were inoculated and examined with immunofluorescence.
Biosynthesis of radiolabeled T-2 toxin by Fusarium tricinctum
Authors: Hagler W M , Mirocha C J , Pathre S V
Published: January 2020

Incubation of Fusarium tricinctum NRRL 3299 on a solid rice medium in the presence of [1-14C]sodium acetate, [2-3H]mevalonic acid, [2-14C]mevalonic acid, or [5-3H]mevalonic acid yielded preparations of radiolabeled T-2 toxin with specific activities of 1.008, 1.64, 0.656, and 7.35 muCi/mmol, respectively.
Primary Production and Biovolume of Various Phototrophic Plankton Size Fractions in Three Southeastern United States Reservoirs
Authors: Tison David L. , Wilde Edward W.
Published: January 2020

Plankton size classes of <3 μm consisting largely of unicellular cyanobacteria accounted for 15 to 40% of the total primary production and generally represented <5% of the total phototrophic plankton biovolume in three South Carolina reservoirs.
Formation and Location of 1,4-β-Glucanases and 1,4-β-Glucosidases from
Penicillium janthinellum
Authors: Rapp Peter , Grote Elisabeth , Wagner Fritz
Published: January 2020

Formation and location of 1,4-β-glucanases and 1,4-β-glucosidases were studied in cultures of
Penicillium janthinellum
grown on Avicel, sodium carboxymethyl cellulose, cellobiose, glucose, mannose, and maltose. Endo-1,4-β-glucanases were found to be cell free, and their formation was induced by cellobiose. 1,4-β-Glucosidases, on the other hand, were formed constitutively and were primarily cell free, but with a small amount strongly associated with the cell wall. Low 1,4-β-glucosidase activities of periplasmic or intracellular origin were also found. A rotational viscosimetric method was developed to measure the total endo-1,4-β-glucanase activity of the culture (broth and solids). By this method, it was possible to determine the endo-1,4-β-glucanase activity not only in the supernatant of the culture but also on the surface of the mycelium or absorbed on residual Avicel. During a 70-liter batch cultivation of
P. janthinellum
, the adsorption of endo-1,4-β-glucanases by residual and newly added 10% Avicel was measured. The adsorption of soluble protein and endo-1,4-β-glucanases by Avicel was found to be largely independent of the pH value but dependent on temperature.
Relationship of Cell Envelope Stability to Substrate Capture in a Marine Psychrophilic Bacterium
Authors: Geesey Gill G. , Morita Richard Y.
Published: January 2020

Cells of a psychrophilic marine bacterium were found to take up a variety of amino acids from seawater. Some of the amino acids that were taken up were released when the cells were exposed to a hypotonic salt solution. The proportion that was released varied according to the amino acid. A pool of the amino acid arginine that was formed during very short periods of exposure of cells to the exogenously supplied amino acid was particularly sensitive to reductions in salinity. In general, exposure to hypotonic salt solutions also resulted in reduced amino acid uptake by the cells. Complete removal of seawater salts (SE treatment) produced obvious structural alterations in the cell envelope, resulting in an even greater reduction in amino acid uptake. Under these conditions, amino acid-binding components were released by the cells. Differential centrifugation and fluorescent antibody studies indicated that arginine-binding components are located on or near the surface of intact cells. The data suggest that substrate receptors were sensitive to reductions in seawater salt concentrations and that lesions at this level affected the organism's substrate uptake and retention capabilities.