bluuebunny/crossref_metadata_2025 huggingface dataset:
Anthraquinones in the biosynthesis of sterigmatocystin by Aspergillus versicolor
Authors: Hsieh D P , Singh R , Yao R C , Bennett J W
Published: January 2020

14C-labeled averufin, versiconal hemiacetal acetate, and versicolorin A were efficiently converted to sterigmatocystin by Aspergillus versicolor, thus providing experimental evidence that these anthraquinones are biosynthetic precursors of sterigmatocystin, a xanthone.
Inclusion of xylan in a medium for the enumeration of total culturable rumen bacteria
Authors: Henning P A , van der Walt A E
Published: January 2020

The influence of the inclusion of xylan in a medium for enumeration of total culturable rumen bacteria was investigated. Maximum colony numbers were obtained on a medium, GCSX-2, which contained 0.033% each glucose and cellobiose and 0.067% each soluble starch and xylan. This medium gave higher colony counts than either medium 98-5 of Bryant and Robinson (J. Dairy Sci. 44:1446-1456, 1961), medium 98-5 of Chung and Hungate (Appl. Environ. Microbiol. 32:649-652, 1976), containing an added lucerne (hemicellulose + cellulose) fiber substrate, or medium GCSX-2 with the added lucerne (hemicellulose + cellulose) fraction. The time of collection of rumen fluid influenced the colony counts on the media containing the lucerne fiber substrate but was without effect on medium GCSX-2.
Antimetabolite sensitivity and magnesium uptake by thermally stressed Vibrio parahaemolyticus
Authors: Heinis J J , Beuchat L R , Boswell F C
Published: January 2020

Metabolic inhibitors were added to a culture medium inoculated with theramlly stressed Vibrio parahaemolyticus to obtain information pertaining to biosynthetic processes required for recovery from heat damage. Ribonucleic acid and protein syntheses, in addition to membrane repair, were required during recovery of injured cells. Neither nucleic acid nor Mg2+ leakage was noted to occur during the time cells were subjected to heat stress. Studies revealed that Mg2+ was apparently taken up by cells of V. parahaemolyticus during the first 30 min after thermal treatment, indicating a possible increased requirement for Mg2+ for membrane and/or ribosome stability and repair.
Antagonism among the normal anaerobic bacteria of the mouse gastrointestinal tract determined by immunofluorescence
Authors: Berg R D
Published: January 2020

Strictly anaerobic Bacteroides sp., Eubacterium sp., and Fusobacterium sp. were isolated from the cecum of a conventional mouse. An immunofluorescent method utilizing rabbit antisera specific for each of these three strains was developed to determine their population levels in the gastrointestinal tracts of gnotobiotic mice. Population levels of these anaerobes in groups of gnotobiotic mice colonized with either Bacteroides, Eubacterium, or Fusobacterium were compared with those of gnotobiotes colonized with all three strains. Bacteroides population levels in gnotobiotes colonized with all three strains were 100-fold less than the Bacteroides population level in gnotobiotes colonized with only the Bacteroides strain. Eubacterium or Fusobacterium population levels were not reduced by the presence of the other anaerobic strains. Thus, strictly anaerobic Eubacterium sp. and Fusobacterium sp. that colonized gnotobiotic mice caused a reduction in the in vivo population levels of a strictly anaerobic Bacteroides sp.
Viral aggregation: quantitation and kinetics of the aggregation of poliovirus and reovirus
Authors: Floyd R , Sharp D G
Published: January 2020

The aggregation of poliovirus and reovirus was followed in buffers at various pH values by means of a single particle analysis (SPA) test. The SPA test used here was modified from the original test reported earlier to prevent disaggregation of virus clumps from invalidating the results. The modified SPA test demonstrated that the efficiency of aggregation, which is a measure of the percentage of collisions which are effective in producing an aggregate, may vary widely depending on the conditions in which the virus is placed. The modified SPA test was also used to demonstrate that the kinetic features of viral aggregation follow the classical laws of colloid particle aggregation, which in turn are solely dependent upon diffusion of the particles as caused by brownian motion.
Viral aggregation: effects of salts on the aggregation of poliovirus and reovirus at low pH
Authors: Floyd R , Sharp D G
Published: January 2020

As a first step toward the understanding of virus particle interactions in water, we have used the modified single particle analysis test to follow the aggregation of poliovirus and reovirus as induced by low pH in suspensions containing varying amounts of dissolved salts. Salts composed of mono-, di-, and trivalent cations and mono- and divalent anions were tested for their ability to reduce or increase the aggregation of these viruses in relation to that obtained by low pH alone. Mono- and divalent cations in concentrations covering those in natural waters were generally found to cause a decrease in aggregation, with the divalent cations having a much greater effectiveness than the monovalent cations. Trivalent ions (Al3+), in micromolar concentrations, were found to cause aggregation over that at low pH alone. Anions, whether monovalent or divalent, had little ability to produce inhibition of viral aggregation, and thus the overall effects were due almost exclusively to the cation. This was true regardless of whether the overall charge on the virus particle was positive or negative, as determined by the relation between the isoelectric point and the pH at which the tests were carried out. Thus, whereas virus particles conform to classical colloid theory in many respects, there are specific exceptions which must be taken into account in the design of any experiment in which viral aggregation is a factor.
Electrophoretic protein patterns and enzyme mobilities in anaerobic coryneforms
Authors: Gross C S , Ferguson D A , Cummins C S
Published: January 2020

The soluble protein patterns and electrophoretic mobilities of malate and succinate dehydrogenases and catalase have been examined in 25 strains of Propionibacterium acnes, P. granulosum, and P. avidum. A distinctive protein pattern for each species was found, and it was possible also to distinguish the serotypes within P. acnes and P. avidum. Strains of P. acnes, P. granulosum, and P. avidum could be differentiated by the mobilities of their malate dehydrogenases. Catalase activity was detected in the soluble fractions of all strains. Catalases from P. acnes and P. avidum strains had the same mobility, whereas that from P. granulosum was slightly slower. Under the conditions used, succinate dehydrogenase activity could be detected, but the patterns were not distinctive.
Interaction of Bacteriophage Infection and Low Penicillin Concentrations on the Performance of Yogurt Cultures
Authors: Verhue Walter M.
Published: January 2020

Bacteriophage infection of a mixed-strain
Streptococcus thermophilus
culture, one strain of which is phage sensitive and the other phage resistant, may induce lysis of both strains. Experiments were carried out with three different phage-resistant strains. One such strain lysed in penicillin-free growth medium and another needed penicillin G (0.005 IU/ml) for lysis, while the third strain continued to grow in the presence of this concentration of antibiotic. Growth of the latter strain was inhibited when the medium contained a relatively high concentration of phage lysin. The different penicillin concentrations required to induce “lysis from without” of these phage-resistant strains correlated with their individual sensitivities to the antibiotic. The apparent relationship between the sensitivities of these strains to penicillin and to phage lysin could be explained by a difference in the degree of polymerization of the cell wall peptidoglycan.
Adhesion of Bacteroides succinogenes in pure culture and in the presence of Ruminococcus flavefaciens to cell walls in leaves of perennial ryegrass (Lolium perenne)
Authors: Latham M J , Brooker B E , Pettipher G L , Harris P J
Published: January 2020

Bacteroides succinogenes and Ruminococcus flavefaciens are two of the most important cellulolytic bacteria in the rumen. Adhesion of B. succinogenes in pure culture, and in mixed culture with R. flavefaciens, to the various types of cell walls in sections of perennial ryegrass (Lolium perenne L. cultivar S24) leaves was examined by transmission and scanning electron microscopy. B. succinogenes adhered to the cut edges of most plant cell walls except those of the meta- and protoxylem. It also adhered, though in much smaller numbers, to the uncut surfaces of mesophyll, epidermal, and phloem cell walls. In mixed culture, both species adhered in significant numbers to the cut edges of most types of plant cell wall, but R. flavefaciens predominated on the epidermis, phloem, and sclerenchyma cell walls. B. succinogenes predominated on the cut edges and on the uncut surfaces of the mesophyll cell walls, and its ability to adhere to uncut surfaces of other cell walls was not affected by the presence of the ruminococcus. Both organisms rapidly digested the epidermal, mesophyll, and phloem cell walls. Zones of digestion were observed around bacteria of both species when attached to the lignified cell walls of the sclerenchyma, but not when attached to the lignified xylem vessels.
Rapid qualitative method for detecting staphylococcal nuclease in foods
Authors: Koupal A , Deibel R H
Published: January 2020

A rapid method for the detection of heat-stable staphylococcal nuclease in foods is described. The procedure consists of an acid precipitation, boiling, and centrifugation followed by enzyme detection in an agar plate containing deoxyribonucleic acid. To test the efficacy of the procedure, purified Staphylococcus aureus nuclease was added to various foods and recovery experiments were performed. Additionally, foods were inoculated and incubated with S. aureus, and the staphylococcal counts were compared with nuclease activity. The results indicate that the procedure possesses merit for a rapid method that can be incorporated into quality control programs. The procedure requires approximately 2.5 h, and it will detect nuclease levels as low as 10 ng/g of food.
Accumulation of 1-trans-2,3-epoxysuccinic acid and succinic acid by Paecilomyces varioti
Authors: Ling E T , Dibble J T , Houston M R , Lockwood L B , Elliott L P
Published: January 2020

The biogenic acids 1-trans-2,3-epoxysuccinic acid and succinic acid accumulate in decationized refiner's blackstrap molasses shake cultures of Paecilomyces varioti Bainier. The maximum accumulation of 1-trans-2,3-epoxysuccinic acid occurred in a medium which contained Cu2+ and Fe3+ at concentrations of 1.0 and 2.0 mM, respectively. The maximum accumulation of succinic acid occurred in a culture medium which contained Cu2+ at a concentration of 0.01 mM and Fe3+ at a concentration of 1.0 mM.
Intermittent illumination increases biophotolytic hydrogen yield by Anabaena cylindrica
Authors: Jeffries T W , Leach K L
Published: January 2020

Intermittent illumination increased H2 and C2H4 yields per unit of light from growing cells and from nitrogren-starved cells by 1.7- and 1.35-fold, respectively, as compared with continuous illumination.
Dependence of Marine Bdellovibrios on Potassium, Calcium, and Magnesium Ions
Authors: Marbach A. , Shilo M.
Published: January 2020

Marine bdellovibrios show a specific requirement for K
+
, Ca
2+
, and Mg
2+
. Potassium is essential for high velocity and seems to be necessary for attachment of the free bdellovibrios. Calcium and magnesium are necessary for attachment and penetration. Magnesium also plays a role in maintaining the integrity of the bdelloplast. The adaptation of these bdellovibrios to the marine environment is manifested by their stringent cation requirements.
Effect of medium composition on the growth and asparaginase production of Vibrio succinogenes
Authors: Albanese E , Kafkewitz K
Published: January 2020

Asparaginase synthesis by Vibrio succinogenes is induced by ammonium ions. Synthesis occurs throughout exponential phase, and in early stationary phase asparaginase accounts for about 5% of the total soluble protein. The organism grows best when fumarate is provided as the terminal electron acceptor of the formate-oxidizing cytochrome system. Yeast extract or enzyme-hydrolyzed proteins are effective nutrient sources. In an ammonium formate-sodium fumarate medium, where maximum growth and asparaginase synthesis occurs, the total enzyme yield (international units per liter of culture) is about one-tenth that obtainable with a good asparaginase-producing strain of Escherichia coli. The energetic inefficiency of V. succinogenes appears to cause a low yield of cells and therefore low total enzyme yield. However, the levels of asparaginase accumulated within cells raise questions about the organism's protein synthesizing system.
Sugar Level, Fermentability, and Acceptability of Straw Treated with Different Acids
Authors: Israilides C. J. , Grant G. A. , Han Y. W.
Published: January 2020

The sugar level, fermentability, and acceptability by voles of ryegrass straw treated with different acids were compared. Sugar release was highest with HCl, but acceptability was best with H
3
PO
4
treatment.
Candida utilis
grew about equally well on all of the treated samples, except the one treated with 0.5 N HCl. That sample supported no growth, possibly because the level of chloride or degradation products of monomeric sugars was too high. Fermentability and palatability of straw were highest when treated with a combination of 0.23 N HCl and 0.15 N H
3
PO
4
. Fermentation with
Aureobasidium pullulans
further increased the palatability of the acid-treated straw.
Inactivation of enteroviruses by ascorbic acid and sodium bisulfite
Authors: Salo R J , Cliver D O
Published: January 2020

Poliovirus type 1, coxsackievirus type A9, and echovirus type 7 were inactivated by sodium bisulfite and ascorbic acid. Inactivation rates depended upon concentration, temperature, and pH. RNA infectivity was lost during inactivation; the capsid was also altered by these inactivating agents, as determined by enzyme sensitivity assays and by tests of adsorption to cells. Structural modifications of the virus particles were not identical, suggesting that the mechanism of inactivation by ascorbic acid differs from that of sodium bisulfite.
Denitrifying Pseudomonas aeruginosa: some parameters of growth and active transport
Authors: Williams D R , Rowe J J , Romero P , Eagon R G
Published: January 2020

Optimal cell yield of Pseudomonas aeruginosa grown under denitrifying conditions was obtained with 100 mM nitrate as the terminal electron acceptor, irrespective of the medium used. Nitrite as the terminal electron acceptor supported poor denitrifying growth when concentrations of less than 15 mM, but not higher, were used, apparently owing to toxicity exerted by nitrite. Nitrite accumulated in the medium during early exponential phase when nitrate was the terminal electron acceptor and then decreased to extinction before midexponential phase. The maximal rate of glucose and gluconate transport was supported by 1 mM nitrate or nitrite as the terminal electron acceptor under anaerobic conditions. The transport rate was greater with nitrate than with nitrite as the terminal electron acceptor, but the greatest transport rate was observed under aerobic conditions with oxygen as the terminal electron acceptor. When P. aeruginosa was inoculated into a denitrifying environment, nitrate reductase was detected after 3 h of incubation, nitrite reductase was detected after another 4 h of incubation, and maximal nitrate and nitrite reductase activities peaked together during midexponential phase. The latter coincided with maximal glucose transport activity.
Storage quality of dark, firm, dry meat
Authors: Newton K G , Gill C O
Published: January 2020

Dark, firm, dry meat contains little or no glucose. Therefore, spoilage bacteria growing on such meat immediately attack amino acids so that spoilage odors and ammonia are detectable at comparatively low cell densities (about 10(6)/cm2).
Minimal water activity for enterotoxin A production and growth of Staphylococcus aureus
Authors: Lotter L P , Leistner L
Published: January 2020

The minimal water activity (alphaw) for growth was correlated with enterotoxin A formation by two strains of Staphylococcus aureus in a salt mixture broth. Within 7 days at 30 degrees C both strains grew and formed enterotoxin A minimally between alphaw 0.864 and 0.867, but at 25 degrees C, the minimal alphaw for both activities was increased to between 0.870 and 0.887 after a 2-week incubation.
D-values of Bacillus pumilus spores on irradiated devices (inoculated product)
Authors: Prince H N
Published: January 2020

The D-values of Bacillus pumilus spores on various devices ranged from 0.14 to 0.23 Mrads. The majority of devices displayed D-values equal to or less than the value obtained on filter paper. Increased resistivity was also encountered.
Viral Pollution of Surface Waters Due to Chlorinated Primary Effluents
Authors: Sattar Syed A. , Westwood J. C. N.
Published: January 2020

The role of chlorinated primary effluents in viral pollution of the Ottawa River (Ontario) was assessed by examining 282 field samples of wastewaters from two different sewage treatment plants over a 2-year period. The talc-Celite technique was used for sample concentration, and BS-C-1 cells were employed for virus detection. Viruses were detected in 80% (75/94) of raw sewage, 72% (68/94) of primary effluent, and 56% (53/94) of chlorinated effluent samples. Both raw sewage and primary effluent samples contained about 100 viral infective units (VIU) per 100 ml. Chlorination produced a 10- to 50-fold reduction in VIU and gave nearly 2.7 VIU/100 ml of chlorinated primary effluent. With a combined daily chlorinated primary effluent output of approximately 3.7 × 10
8
liters, these two plants were discharging 1.0 × 10
10
VIU per day. Because the river has a mean annual flow of 8.0 × 10
10
liters per day, these two sources alone produced a virus loading of 1.0 VIU/8 liters of the river water. This river also receives at least 9.0 × 10
7
liters of raw sewage per day and undetermined but substantial amounts of storm waters and agricultural wastes. It is used for recreation and acts as a source of potable water for some 6.0 × 10
5
people. In view of the potential of water for disease transmission, discharge of such wastes into the water environment needs to be minimized.
Potential sources of error during virus thermal inactivation
Authors: Tierney J T , Larkin E P
Published: January 2020

A review of virus thermal inactivation data published in the literature demonstrated variations in reported virus resistance. Examination of the methods used indicated that numerous studies were made by heat processing virus suspensions in test tubes. Duplication of some of the methods using milk suspensions of poliovirus 1 showed virus persistence after heating as a result of uneven temperature distribution inside the test tubes. Unless the containers (preferably sealed ampoules or capillary tubes) are completely submerged in the water bath and agitated vigorously, apparent virus persistence may be encountered.
Comparative Sensitivity of Various Cell Culture Systems for Isolation of Viruses from Wastewater and Fecal Samples
Authors: Schmidt Nathalie J. , Ho Helen H. , Riggs John L. , Lennette Edwin H.
Published: January 2020

In efforts to define the most sensitive cell culture systems for recovery of viruses from wastewaters, 181 samples were inoculated in parallel into tube cultures of various cell types and were plaqued in bottle and petri dish cultures of three types of monkey kidney cells. Polioviruses were recovered most frequently in the RD line of human rhabdomyosarcoma cells, group A coxsackieviruses in RD and human fetal diploid kidney (HFDK) cells, group B coxsackieviruses in the BGM line of African green monkey kidney cells, echoviruses in RD and primary rhesus monkey kidney (RhMK) cells, and reoviruses in RhMK cells. BGM cells were unsatisfactory for recovery of viruses other than polioviruses and group B coxsackieviruses, and a line of fetal rhesus monkey kidney (MFK) was not a satisfactory substitute for primary RhMK. With RhMK cells, comparable numbers of virus isolations were made in tube cultures and in plaque assays conducted in bottle cultures, but with BGM and MFK cells, fewer isolations were made by plaquing than by inoculation of tube cultures. In comparative plaque assays on fecal samples under three different overlays in bottle and plate cultures of RhMK, BGM, and MFK cells, it was found that plaquing in the most sensitive system, RhMK, was less efficient for virus recovery than was inoculation of tube cultures of RhMK or HFDK cells. Overall, plaque assays performed in petri dishes in a CO
2
incubator yielded fewer virus isolates than did parallel plaque assays performed in closed bottle cultures. Other limitations of plaque assays for recovery of human enteric viruses are discussed.
Thermophilic Iron-Oxidizing Bacteria Found in Copper Leaching Dumps
Authors: Brierley James A.
Published: January 2020

Rod-shaped bacteria capable of oxidizing ferrous iron at 55°C were cultured from samples of a copper mine leach dump. Yeast extract or cysteine was required by these
Thiobacillus
-like bacteria for growth, using ferrous iron as an energy source.
Anaerobic fecal bacteria of the baboon
Authors: Brinkley A W , Mott G E
Published: January 2020

The predominant bacterial genera of baboon feces were enumerated and identified by established procedures. The predominant genera isolated were Lactobacillus, Eubacterium, Streptococcus, and Bacteroides.
Evaluation of Sclerotinia sclerotiorum as a potential mycotoxin producer on soybeans
Authors: Ciegler A , Burbridge K A , Ciegler J , Hesseltine C W
Published: January 2020

Solvent extracts of Sclerotinia sclerotiorum sclerotia were nontoxic to mice and chicken embryos; psoralens were not detected. Solvent extracts of soybeans inoculated with 10 strains of S. sclerotiorum were toxic on injection but nontoxic on per os administration to mice. The presence of chlorinated hydrocarbons in the soybeans may partially help explain toxicity by intraperitineal injection.
Primary Klebsiella identification with MacConkey-inositol-carbenicillin agar
Authors: Bagley S T , Seidler R J
Published: January 2020

MacConkey-inositol-carbenicillin agar has successfully been used as a primary selective medium for Klebsiella enumeration. With pure cultures, nearly 100% recovery of Klebsiella was observed by membrane filtration. With environmental samples using membrane filtration, 95% of typical pink- to red-colored colonies were verified as Klebsiella, as opposed to only 1% of yellow background colonies. Recovery of Klebsiella on MacConkey-inositol-carbenicillin agar was as good or better than on mEndo agar LES (Difco Laboratories). Recovery and percent colony confirmation with MacConkey-inositol-carbenicillin agar were greater than for other proposed Klebsiella selective media.
Purification of the protein crystal from Bacillus thuringiensis by zonal gradient centrifugation
Authors: Ang B J , Nickerson K W
Published: January 2020

A method is described for the large-scale purification of the Bacillus thuringiensis protein crystal by zonal gradient centrifugation. NaBr gradients are employed in a Beckman J21-B centrifuge equipped with a JCF-Z rotor.
Enrichment procedures for isolating salmonellae from raw meat and poultry
Authors: Thomason B M , Dodd D J
Published: January 2020

The combined use of direct enrichment in tetrathionate broth containing brilliant green dye and preenrichment in buffered peptone-water followed by enrichment in tetrathionate broth yielded the maximal recovery of salmonellae from raw meat and poultry samples.
Degradation of Tyrosine in Anaerobically Stored Piggery Wastes and in Pig Feces
Authors: Spoelstra Sierk F.
Published: January 2020

Radioactively labeled compounds that might be intermediates in the anaerobic degradation of tyrosine were added to pig feces and to stored piggery wastes. Changes in the compounds were followed by using thin-layer and gas chromatography. In feces,
p
-cresol and 3-phenylpropionic acid were the end products of tyrosine metabolism; in anaerobically stored mixed wastes, phenol,
p
-cresol, and minor quantities of phenylpropionic acid were formed. Schemes were proposed for the degradation of tyrosine in pig feces and in mixed wastes.
Carotene-superproducing strains of Phycomyces
Authors: Murillo F J , Calderón I L , López-Díaz I , Cerdá-Olmedo E
Published: January 2020

Production of beta-carotene by wild-type Phycomyces blakesleeanus can be stimulated by light, chemicals, regulatory mutations, and sexual interaction between mycelia of opposite sex. Through genetic manipulations, we have isolated strains which have simultaneously and constitutively incorporated several of these stimulatory effects. In the dark and in a simple medium, some of the strains produce up to 25 mg of beta-carotene per g (dry weight), or about 500 times the wild-type production under the same conditions. High lycopene-producing strains have also been isolated by using carR mutants, which are blocked in the conversion of lycopene to beta-carotene. These strains should be useful in both industrial production of these pigments and basic research related to carotenogenesis.
Dry-heat destruction of lipopolysaccharide: design and construction of dry-heat destruction apparatus
Authors: Robertson J H , Gleason D , Tsuji K
Published: January 2020

A dry-heat oven with automatic, multiple-sample introduction and withdrawal has been constructed to achieve instantaneous heating and cooling of samples. The oven temperature fluctuation at set points of 170 to 250 degrees C was +/- 0.1 degrees C, with temperature variation between the replicate samples of +/- 0.2 degrees C. Correction required for a sample come-up time was minimal, i.e., less than 0.25 min of the dry-heat destruction time.
Bioproduction of [14C]ochratoxin A in submerged culture
Authors: Lillehoj E B , Aalund O , Hald B
Published: January 2020

A number of Aspergillus and Penicillium species were tested for production of ochratoxin A (OA) in several media. After 8 days of static incubations of submerged cultures at 28 degrees C, toxin yields of 25 and 30 micrograms/ml were obtained with Aspergillus alliaceus NRRL 4181 in Ferreirás and 2% yeast extract-4% sucrose media, respectively. However, the largest production observed in the preliminary screening was 54 micrograms/ml; this highest level was produced by A. sulphureus NRRL 4077 in a modified Czapek solution. The medium contained the basal salts and sucrose of Czapek plus urea (3%) and corn steep liquor (0.5% solids). A time study of toxin production demonstrated maximum yield of 350 micrograms/ml by the A. sulphureus isolate in the modified Czapek medium after 11 days of static incubation at 28 degrees C. The optimal production conditions were employed in additional tests designed to measure the efficiency of 14C incorporation from sodium [1-14C]-acetate into OA. Samples (20 microCi) of sodium acetate were added to separate culture flasks at 24-h intervals during the initial 9 days of the fermentation. Addition of [14C]acetate on day 4 of incubation provided the maximum yield of labeled OA. The highest specific activity of labeled toxin obtained was 0.07 microCi/mg of OA and the maximum incorporation rate of labeled acetate was 5.3%.
Frequency of F116-mediated transduction of Pseudomonas aeruginosa in a freshwater environment
Authors: Morrison W D , Miller R V , Sayler G S
Published: January 2020

Transduction of Pseudomonas aeruginosa streptomycin resistance by a generalized transducing phage, F116, was shown to occur during a 10-day incubation in a flow-through environmental test chamber suspended in a freshwater reservoir. Mean F116 transduction frequencies ranged from 1.4 X 10(-5) to 8.3 X 10(-2) transductants per recipient during the in situ incubation. These transduction frequencies were comparable to transduction frequencies determined in preliminary laboratory transduction experiments. The results demonstrate the potential for naturally occurring transduction in aquatic environments and concurrent environmental and ecological ramifications.
Comparison of Four Agar Plating Media with and Without Added Novobiocin for Isolation of Salmonellae from Beef and Deboned Poultry Meat
Authors: Moats W. A.
Published: January 2020

Four plating media, Hektoen enteric (HE), xylose-lysine deoxycholate (XLD), tryptic soy-xylose-lysine (TSXL), and tryptic soy-brillant green (TSBG) agars with and without 10 mg of added novobiocin per ml, were evaluated for recovery of
Salmonella
from roast beef and deboned turkey. Colonies producing a reaction typical of H
2
S-positive salmonellae (alkaline with black centers) were picked. On the media without novobiocin, from 109 determinations on 75 samples, number of salmonellae found and false-positives were, respectively: HE—13, 58; XLD—17, 18; TSXL—23, 0; TSBG—22, 7. When novobiocin was present the corresponding results were: HE—17, 24; XLD—21, 2; TSXL—23, 3; TSBG—20, 7. A total of 25 determinations were positive on one or more agars. False-positives on HE and XLD without novobiocin were predominantly
Proteus
, which were almost totally eliminated by addition of 10 mg of novobiocin per liter. If alkaline H
2
S-negative colonies had been considered, many more false-positives would have been found on HE and XLD but not on TSBG or TSXL. Addition of novobiocin markedly improved isolations of salmonellae from XLD and HE and reduced the number of false-positives. Addition of novobiocin did not improve performance of TSXL and slightly impaired differentiation of salmonellae from
Citrobacter
on TSBG. XLD with novobiocin and TSXL are highly specific for H
2
S-positive salmonellae, and the appearance of
Salmonella
-like colonies on these media can be considered a presumptive test for H
2
S-positive salmonellae.
Use of Cetylpyridinium Chloride in the Decontamination of Water for Culture of Mycobacteria
Authors: du Moulin Gary C. , Stottmeier Kurt D.
Published: January 2020

Selective decontamination of large-volume aqueous samples for mycobacterial culture can be achieved with overnight exposure to 0.04% cetylpyridinium chloride.
Use of an internal standard in monitoring the bacterial degradation of crude oil
Authors: Mrsny R J , Barles R W , Chin D , Enevold K C , Thomas B R , Wheelis M L
Published: January 2020

Hexachloroethane is nonvolatile, insoluble in water, and apparently not toxic to or metabolized by bacteria. Its addition to cultures growing at the expense of crude oil thus provides an internal standard against which the rate of degradation of individual crude oil components can be conveniently and reproducibly measured.
Diversity of
Rhizobium leguminosarum
in the Palouse of Eastern Washington
Authors: Mahler R. L. , Bezdicek D. F.
Published: January 2020

Serology, antibiotic resistance, litmus milk reaction, and ability to fix nitrogen in peas were methods employed in studying the diversity of
Rhizobium leguminosarum
. The two serogroups identified were related to the position on the soil slope where isolated were taken.
Correlation between hemin content and the chemiluminescent luminol reaction with bacteria
Authors: Ewetz L , Thore A
Published: January 2020

Protohemin and covalently bound hemin were determined in eight aerobic bacterial strains. A good correlation between protohemin content and luminol reactivity was found. The ratio of luminol reaction to protohemin for the eight investigated strains was essentially identical to that of pure protohemin, 0.7 X 10(16) mV/mol. Covalently bound hemin contributed to the chemiluminescence to a minor extent only (0.7 X 10(14) mV/mol, in accordance with earlier observations of the lower reactivity of cytochrome c and related compounds. A difference in reaction kinetics of the luminol reaction with covalently bound hemin (slower reaction than protohemin) and protohemin was observed in vivo as well as in vitro. The phenomenon could be used to differentiate between strains with different hemin composition.
Improvement in the sensitivity of DNA polymerase I-deficient Escherichia coli for detecting mutagens and carcinogens
Authors: Venturini S , Monti-Bragadin C
Published: January 2020

The sensitivity of a polA strain to the antibacterial activity of mutagens and carcinogens may be increased by inserting one or both of the following characteristics, a lexA mutation or the R391 bacterial plasmid. The effects of the lexA mutation and the plasmid appear to be additive. The differential sensitivity of a polA lexA (R391) strain could be adapted as a preliminary screening test for mutagens and potential carcinogens.
Distribution of ice nucleation-active bacteria on plants in nature
Authors: Lindow S E , Arny D C , Upper C D
Published: January 2020

A replica plating method for rapid quantitation of ice nucleation-active (INA) bacteria was developed. Leaf washings of plant samples from California, Colorado, Florida, Louisiana, and Wisconsin were tested for the presence of INA bacteria. Of the 95 plant species sampled, 74 were found to harbor INA bacteria. Only the conifers were, as a group, unlikely to harbor INA bacteria. All of the INA bacteria isolated resembled either Pseudomonas syringae or Erwinia herbicola. Sufficient numbers of INA bacteria were present on the samples to account for the ice nuclei associated with leaves that are necessary for freezing injury to occur. Numbers of INA bacteria were large enough to suggest that plant surfaces may constitute a significant source of atmospheric ice nuclei.
Microbial succession and mineral leaching in an artificial coal spoil
Authors: Harrison A P
Published: January 2020

An artificial pyritic coal spoil was prepared and examined over a period of 1.5 years for changes in the population of various physiological varieties of bacteria and also for mineral leaching. Heterotrophic bacteria were the first to dominate the spoil, acquiring a population of 10(7) cells per g within 2 weeks. Bacteria capable of utilizing choline sulfate as the sole source of energy comprised approximately 1% of the total heterotrophic bacteria. Sulfur-oxidizing autotrophic bacteria (Thiobacillus) and finally iron-oxidizing bacteria (Thiobacillus ferrooxidans) increased in the population, the latter becoming the dominant species where acidity was greatest. Partition of species paralleled partition of acidity in the spoil. Maximum acidity (pH 2.6) and maximum population of T. ferrooxidans (greater than 10(7) cells per g) occurred at the summit. Molds (notably, Aspergillus), algae (Chlorococcales, Oscillatoria, Navicula), cilliated and flagellated protozoa, an arthropod (Podura aquatica), and a moss (aberrant Physcomitrium pyriforme) were observed. The mineral salts leached from the spoil, in decreasing order, were the sulfates of magnesium (predominantly hexahydrite), calcium (gypsum), sodium, aluminum (alunogenite), and iron.
Identification of detergents as components of wastewater sludge that modify the thermal stability of reovirus and enteroviruses
Authors: Ward R L , Ashley C S
Published: January 2020

The agent in wastewater sludge previously shown to reduce the heat required to inactivate reovirus (R. L. Ward and C. S. Ashley, Appl. Environ. Microbiol. 34:681--688, 1977) was "separated" from other sludge components and analyzed by infrared spectroscopy. The infrared spectrum of this material was quite similar to the spectra of commercial anionic detergents, and subsequent analyses of the fractionated sludge samples revealed that anionic detergents in sludge were copurified with the virucidal activity. Further measurements on the virucidal activities of specific detergents revealed that ionic detergents reduce the heat required to inactivate reovirus, that cationic detergents are more active than anionic, and that nonionic detergents are inactive. Several detergents were also shown to protect poliovirus and other enteroviruses against inactivation by heat. These results indicate that ionic detergents are the major component in wastewater sludge that reduce the thermal stability of reovirus and, in addition, that detergents are able to protect enteroviruses against heat.
Heat inactivation of enteric viruses in dewatered wastewater sludge
Authors: Ward R L , Ashley C S
Published: January 2020

The effect of moisture content on the rates of heat inactivation of enteric viruses in wastewater sludge was determined. The protective effect of raw sludge on poliovirus previously observed (R. L. Ward, C. S. Ashley, and R. H. Moseley, Appl. Environ. Microbiol. 32:339--346, 1976) was found to be greatly enhanced in sludge dewatered by evaporation. Other enteroviruses responded in a similar fashion. This effect did not appear to be due merely to the state of dryness of the sludge samples because in humus-deficient soil, a relatively inert material, the rate of poliovirus inactivation by heat was not significantly altered through dewatering. Instead, this effect appeared to have been caused by protective substances in the sludge, such as detergents, which are concentrated through dewatering. As reported previously (R. L. Ward and C. S. Ashley, Appl. Environ. Microbiol. 34:681-688, 1977; R. L. Ward and C. S. Ashley, Appl. Environ. Microbiol 36:889--897, 1978) raw sludge is not protective of reovirus, but, instead, the ionic detergents in sludge cause the rate of heat inactivation of this virus to be accelerated. Dewatering of sludge, however, was found to partially reverse this virucidal effect. Evidence is presented indicating that this reversal is caused by an unidentified protective substance in sludge also concentrated through dewatering. Finally, it was shown that the effects of raw sludge on heat inactivation of poliovirus and reovirus are greatly reduced by composting, a result that correlated with the degradation of detergents.
Bacteriocin-Like Substances Produced by
Rhizobium japonicum
and Other Slow-Growing Rhizobia
Authors: Gross D. C. , Vidaver A. K.
Published: January 2020

Bacteriocin-like substances were commonly produced by slow-growing
Rhizobium japonicum
and cowpea rhizobia on an L-arabinose medium. Antagonism between strains of
R. japonicum
was not detected in vitro; however, such strains were often sensitive to some bacteriocins produced by cowpea rhizobia. Inhibitory zones (2 to 8 mm from colony margins), produced by 58 of 66
R. japonicum
test strains, were reproducibly detected with
Corynebacterium nebraskense
as an indicator. Quantitative production was not related to symbiotic properties of effective strains, since nine noninfective strains and one ineffective strain produced bacteriocin. Eight
R. japonicum
strains that did not produce bacteriocin nevertheless formed effective nodules on soybeans.
R. japonicum
strains that produced bacteriocin in vitro had no antagonistic effect on nonproducer strains during soybean nodulation. Under controlled conditions, a nonproducer (3I1b135) predominated over a bacteriocin producer (3I1b6) when inoculated at 1:1 and 1:9 ratios. Depending on the particular ratio, up to 38% of the total nodules formed were infected with mixed combinations. The bacteriocin(s) had a restricted host range and antibiotic-like properties which included the ability to be dialyzed and resistance to heat (75 to 80°C, 30 min), Pronase, proteinase K, trypsin, ribonuclease, and deoxyribonuclease.
R. japonicum
strains representing genetic, serological, cultural, and geographic diversity were differentiated into three groups on the basis of bacteriocin production.
Silica gel media for isolating and studying bacteria under hydrostatic pressure
Authors: Dietz A S , Yayanos A A
Published: January 2020

Individual colonies of micrococcus euryhalis and of a marine bacterial isolate were grown in pour tubes under hydrostatic pressure. The medium was prepared in a silica sol, and gelation was effected at 4 degrees C by addition of salts to achieve concentrations found in seawater.
Isolation of a Unique Marine Bacterium Capable of Growth on a Wide Variety of Polysaccharides from Macroalgae
Authors: Quatrano Ralph S. , Caldwell Bruce A.
Published: January 2020

A unique marine bacterium has been isolated which can be cultured on a variety of polysaccharides and cell wall preparations from red and brown algae.
Low-intensity microwave radiation and the virulence of Agrobacterium tumefaciens strain B6
Authors: Moore H A , Raymond R , Fox M , Galsky A G
Published: January 2020

When virulent cells of Agrobacterium tumefaciens strain B6 were exposed to low-level microwave radiation at a frequency of 10,000 MHz and an intensity of 0.58 mW/cm2 for 30 to 120 min, a 30 to 60% decrease in their ability to produce tumors on potato and turnip disks was observed. This microwave exposure did not affect the viability of these bacteria or their ability to attach to a tumor-binding site nor did it induce thermal shock. This loss of virulence was reversible within 12 h.
Pectinolytic enzymes of large rumen treponemes
Authors: Wojciechowicz M , Ziołecki A
Published: January 2020

Large spiral organisms isolated from the rumen of cattle produced and released into the external environment a complex of pectinolytic enzymes, consisting mainly of poly(1,4-alpha-D-galacturonide) lyase (EC 4.2.2.2, formerly EC 4.2.99.3), most active at pH 8.0 to 9.0, and another enzyme acting at pH below 7.0, probably a poly(1,4-alpha-D-galacturonide) glycanohydrolase (EC 3.2.1.15). The mixture of enzymes degraded polygalacturonate to saturated and unsaturated monogalacturonates as the end products. A pectin pectylhydrolase (pectinesterase) (EC 3.1.1.11) was also present in the clarified cultures.
Large-scale production of mouse mammary tumor virus in the absence of endogenous murine leukemia virus
Authors: Benton C V , Harshman J S , Robinson O R , Shibley G P
Published: January 2020

A system for the large-scale production and purification of mouse mammary tumor virus in the absence of detectable endogenous murine leukemia virus is described. By utilizing the Mm5mt/c1 cell line established from an adenocarcinoma of a C3H mouse, the continuous production of over 25,000 liters of mouse mammary tumor virus-containing tissue culture fluids has been achieved. By the strict adherence to well-defined tissue culture conditions, mammary tumor virus production was accomplished without the expression of murine leukemia virus. Various biochemical and immunological systems were established for the rapid and precise detection of the endogenous leukemia virus, the expression of which could be enhanced under conditions of culture stress.
Membrane filtration of food suspensions
Authors: Sharpe A N , Peterkin P I , Dudas I
Published: January 2020

Factors affecting the membrane filtration of food suspensions were studied for 58 foods and 13 membrane filters. Lot number within a brand, pore size (0.45 or 0.8 micrometer), and time elapsed before filtration had little effect on filterability. Brand of membrane filter, flow direction, pressure differential, age (microbiological quality) of the food, duration of the blending process, temperature, and concentration of food in the suspension had significant and often predictable effects. Preparation of suspensions by Stomacher (relative to rotary blender) addition of surfactant (particularly at elevated temperature) and prior incubation with proteases sometimes had dramatic effects of filterability. In contrast to popular opinion, foods can be membrane filtered in quantities pertinent to the maximums used in conventional plating procedures. Removal of growth inhibitors and food debris is possible by using membrane filters. Lowering of the limits of detection of microorganisms by concentration on membrane filters can be considered feasible for many foods. The data are particularly relevant to the use of hydrophobic grid-membrane filters (which are capable of enumerating up to 9 X 10(4) organisms per filter) in instrumented methods of food microbiological analysis.
Membrane filter enumeration method for Clostridium perfringens
Authors: Bisson J W , Cabelli V J
Published: January 2020

A membrane filter procedure has been developed for the rapid quantitation of C. perfringens in the aquatic environment. Background growth is inhibited by the use of D-cycloserine, polymyxin B sulfate, and incubation at 45 degrees C. Differential characteristics include the fermentation of sucrose, production of acid phosphatase, and the absence of beta-D-glucosidase activity. The medium is prepared as follows (in grams per 100 ml of distilled water): tryptose, 3.0; yeast extract, 2.0; sucrose, 0.5; L-cysteine, 0.1; MgSO4. 7H2O, 0.01; bromocresol purple, 0.004; and agar, 1.5. The ingredients are dissolved, and the pH is adjusted to 7.6. After autoclaving at 121 degrees C for 15 min, the medium is allowed to cool at 50 degrees C, and the following are added per 100 ml: D-cycloserine, 40 mg; polymyxin B sulfate, 2.5 mg; indoxyl-beta-D-glucoside, 60 mg; 2.0 ml of a filter-sterilized 0.5% phenolpthalein diphosphate solution; and 0.2 ml of a filter-sterilized 4.5% FeCl3.6H2O solution. Enumeration of C. perfringens in a water sample is completed within 18 to 24 h. The verification of typical colonies was 93%. The average recovery from peptone-water spore suspensions of five strains was 79%, and that from filter-sterilized seawater suspensions was 90%. The precision of the method was approximately equal to that expected from random error alone. Confirmed recoveries of C. perfringens from water and sewage samples generally were greater than those by the Bonde pour tube method.
Effect of Ammonium Chloride and Methionine Sulfoximine on the Acetylene Reduction of Detached Root Nodules of Peas (
Pisum sativum
)
Authors: Houwaard F.
Published: January 2020

Acetylene-reducing activity of detached pea nodules was determined by submerging the nodules in buffer solution [tris(hydroxymethyl)aminomethane-hydrochloride, pH 7.4] containing 100 mM sodium succinate and incubating under a gas phase of 90% O
2
and 10% C
2
H
2
. The nitrogenase activity was 4 to 8 μmol of C
2
H
4
formed per g of nodule fresh weight per h and remained constant for at least 4 h. Addition of NH
4
Cl to the buffer solution (at a concentration of 10 mM or more) resulted in a significant decrease of nitrogenase activity, which was more pronounced at higher concentrations of ammonium chloride. The inhibition of nitrogenase activity by NH
4
Cl was reversible; when the NH
4
Cl-containing buffer solution was replaced by buffer without NH
4
Cl, the original activity was partly restored. Treatment of the nodules with NH
4
Cl had almost no effect on the amount of nitrogenase, as measured by the acetylene-reducing activity of ethyl-enediaminetetraacetate-toluene-treated bacteroid suspensions. The effect of NH
4
Cl was largely eliminated by simultaneous addition of 10 mM methionine sulfoximine to the assay solution. This suggests that the assimilation of ammonium ions by glutamine synthetase controls the functioning of nitrogenase activity in the nodules. However, no effect of glutamine, glutamate, or aspartate on the acetylene reduction by detached nodules could be detected.
Preferential binding of radiolabeled zearalenone to a protein fraction of Fusarium roseum graminearum
Authors: Inaba T , Mirocha C J
Published: January 2020

Zearalenone [6-(10-hydroxy-6-oxo-trans-1-undecenyl)beta-resorcyclic acid lactone] is a hormone produced by Fusarium spp. which regulates the sexual stage in F. roseum. 3H- and 14C-labeled zearalenone were found to bind preferentially to one of two peaks containing uncharacterized proteins obtained from the cytosol of young mycelium and resolved by gel column chromatography. The proteins were partially purified by successive resolution on Sephadex G-100, Sephadex G-200, and BioGel P-300. Free zearalenone (37%) was reisolated from the purified proteins after resolution by thin-layer chromatography or partitioning with ethyl acetate.