bluuebunny/crossref_metadata_2025 huggingface dataset:
Constant release of photosynthate from marine phytoplankton
Authors: Smith D F , Wiebe W J
Published: January 2020

The release rate of dissolved organic carbon (DOC) by unialgal cultures and natural phytoplankton assemblages was constant over a wide range of dissolved inorganic carbon concentrations. DOC release was not proportional to the particulate organic carbon production rate. We postulate that intracellular DOC, fated for release, exists either as a separate pool from that leading to particulate organic carbon production or that there is active metabolic control on one portion of a common pool.
Metabolism of DDT analogues by a Pseudomonas sp
Authors: Francis A J , Spanggord R J , Ouchi G I , Bramhall R , Bohonos N
Published: January 2020

A Pseudomonas sp. rapidly metabolized several nonchlorinated analogues of DDT, with the exception of 2,2-diphenylethanol, as the sole carbon source. Several of the mono-p-chloro-substituted diphenyl analogues were also metabolized as the sole carbon source by the bacterium. The resulting chlorinated aromatic acid metabolites were not further metabolized. The isolate was unable to metabolize p,p'-dichlorodiphenyl analogues as the sole carbon source.
Effects of added germination agents on loss of optical density in electron-irradiated spores
Authors: Stogaitis G , Lefebvre G M
Published: January 2020

Spores of Bacillus megaterium ATCC 14581, subjected to partial-cell iradiation, were exposed to either lysozyme, H2O2, or glucose in an attempt to reduce or eliminate the nonmonotonic behavior in curves of percentage of germination versus energy, obtained when such spores were resuspended in phosphate buffer alone. Except at the lower doses. H2O2 effectively eliminated this anomalous dip in these curves, whereas lysozyme amplified it greatly. Glucose was generally ineffective. Coinciding with the increases in optical density when lysozyme was present was the formation of an occluding product.
Characterization of microbial isolates from an estuarine ecosystem: relationship of hydrocarbon utilization to ambient hydrocarbon concentrations
Authors: Buckley E N , Jonas R B , Pfaender F K
Published: January 2020

Water collected at 12 sites in the Neuse River estuary of North Carolina was analyzed for total viable counts on three isolation media (Trypticase soy agar [TSA], marine agar 2216, Sabouraud agar) and total hydrocarbons by fluorescence spectroscopy. Counts of 3.9 X 10(1) to 3.8 X 10(3) cells/ml were found for total heterotrophs, well within the range commonly reported for marine and estuarine waters. Generally, marine agar 2216 gave higher counts than TSA at stations with salinities greater than 6.0 mg/ml; TSA gave higher counts than marine agar 2216 at sites with salinities less than 4.0 mg/ml. The microbial species isolated on the three media agree well with those previously reported for estuarine microbial communities. Water analyses, using XAD-2 resin and fluorescence spectroscopy, revealed petroleum hydrocarbon concentrations in the range of 5 to 79 ng/ml. Representatives of the microbial species isolated from these communities were tested individually for their ability to grow using kerosene as a sole source of carbon and energy. At all but two stations, the majority of the species isolated were able to grow on hydrocarbons, indicating that this ability is widespread even in environments not subjected to high levels of hydrocarbon pollution.
Effect of storage time and temperature and the variation among replicate tests (on different days) on the performance of spore disks and strips
Authors: Smith G M , Pflug I J , Chapman P A
Published: January 2020

Laboratory-prepared spore disks were stored for 96 weeks at 22 degrees C with 50% relative humidity (RH) and at 4 degrees C with less than 1% RH. At the same time commercial spore strips were stored for 64 weeks at 22 degrees C with 50% RH. The spore count per unit and the heat resistance were measured at the beginning of the experiment and after 16, 32, 48, 64, 80, and 96 weeks of storage. The laboratory-prepared spore disks stored at 4 degrees C with less than 1% RH showed less change in numbers of spores per disks and decrease in the survival time than did the disks stored at 22 degrees C with 50% RH. Both the laboratory-prepared spore disks and the commercial spore strips stored at 22 degrees C with 50% RH decreased in survival times with increased storage time. The relative change in the survival times with storage was less for the commercial spore strips than for the laboratory-prepared spore disks.
Biochemistry of Vibrio cholerae virulence: purification of cholera enterotoxin by preparative disc electrophoresis
Authors: Lewis A C , Richardson S H , Sheridan B
Published: January 2020

Procedures for cholera enterotoxin purification previously developed in this labarotory were not applicable to large-scale purification, and these methods resulted in low yields of pure toxin. An efficient scheme has been developed whereby pure cholera enterotoxin can be obtained from 6 to 8 liters of culture supernatant fluid. This method consists of concentration by membrane ultrafiltration followed by gel filtration and cation-exchange chromatography. Pure cholera enterotoxin of high biological potency was obtained after a final step of preparative acrylamide gel electrophoresis. The degree of purity of the toxin-antigen as well as its biological activity were determined at various setps of purification. This alternate technique for purification is offered because of the widespread interest in cholera enterotoxin as a specific stimulator of adenyl cyclase.
Specimen housing unit for cinemicrographic studies in the vertical plane
Authors: Wilkins J R , Tynan C I , Boykin E H
Published: January 2020

A compact housing unit for low-power (X6 to X50) cinemicrographic studies of microbial specimens in the vertical plane is described. This unit was used successfully to record the development of a "halo" of cells around subsurface colonies of Escherichia coli.
Preparation of pure microbiological samples for pyrolysis of gas-liquid chromatography studies
Authors: Oxborrow G S , Fields N D , Puleo J R
Published: January 2020

Bacterial samples were prepared for pyrolysis gas-liquid chromatography using cells grown on membrane filters. Pyrochromatograms were reproducible when cells harvested from the filters were pyrolyzed without being washed.
Inhibition of aflatoxin formation by 2-mercaptoethanol
Authors: Gupta S K , Maggon K K , Venkitasubramanian T A
Published: January 2020

2-Mercaptoethanol inhibits growth of Aspergillus parasiticus NRRL 3240 and aflatoxin formation by the fungus. When added to the resuspended medium, 2-mercaptoethanol inhibited [1-14C]acetate incorporation into both aflatoxins and neutral lipids, thereby showing that it acts at an early stage of aflatoxin biosynthesis. The inhibition is probably due to its chelating action on zinc, which is essential for aflatoxin production. It is proposed that any chelating agent that selectively binds to zinc will inhibit aflatoxin formation.
Rapid detection of bacterial endotoxins in drinking water and renovated wastewater
Authors: Jorgensen J H , Lee J C , Pahren H R
Published: January 2020

A pilot study was conducted to determine the feasibility of using the Limulus endotoxin assay to detect endotoxins in potable waters and from reclaimed advanced waste treatment (AWT) plant effluents. Water samples were tested using both Limulus lysates prepared in our laboratory and a commercial product, Difco Pyrotest. The Limulus assay procedure was easily adapted to the testing of water samples for endotoxin. Measured endotoxin concentrations varied from 0.78 ng/ml to 1,250 ng/ml. Levels of endotoxin were not predictable based on whether the water was drinking water or AWT water, i.e., some AWT water samples had less endotoxin activity than some samples of drinking water, and some AWT waters had greater endotoxin activity than drinking water. Only three of the water samples tested were free of any detectable endotoxin. Breakpoint chlorination procedures seemed to reduce measurable endotoxin content, whereas passage through activated carbon columns was associated with greater final endotoxin concentrations in test waters.
Silica gel medium to detect molds that produce aflatoxin
Authors: Torrey G S , Marth E H
Published: January 2020

A chemically defined nutrient solution containing tartaric acid was made solid by mixing it with an alkaline silicate solution. Production of aflatoxin by asperfilli growing on the silica gel medium coincided with the presence of a blue fluorescent area surrounding colonies, as observed under long-wave ultraviolet light. Presence of aflatoxin in the medium was confirmed by drying the gels, extracting them with chloroform-methanol, and examining extracts for fluorescent materials by viewing them on thin-layer chromatograms under ultraviolet light.
Stimulatory Effect of Malo-Lactic Fermentation on the Growth Rate of
Leuconostoc oenos
Authors: Pilone Gordon J. , Kunkee Ralph E.
Published: January 2020

Although
l
-malic acid is not an energy source for the malo-lactic organism
Leuconostoc oenos (L. citrovorum)
ML 34, the growth rate of the organism was found to be greatly increased by malo-lactic fermentation (the decarboxylation of
l
-malic acid to
l
-lactic acid). The stimulation was especially striking at the low pH (below pH 4) of wine, the natural habitat of this bacterium. The stimulation of growth did not result from changes in pH that accompany malo-lactic fermentation. Thus, these results suggest a biological function of malo-lactic fermentation.
Factors affecting catalase level and sensitivity to hydrogen peroxide in Escherichia coli
Authors: Yoshpe-Purer Y , Henis Y
Published: January 2020

Composition of the culture medium, growth phase, and temperature play important roles in the sensitivity of Escherichia coli to H2O2. The medium and growth phase affected the sensitivity of the cells to H2O2 by modifying the amount of catalase synthesized by them, whereas the effect of temperature was due to the thermolability of the enzyme. Since catalase is unstable in the presence of its substrate, the correlation between the catalase level in the cells and their sensitivity to H2O2 could be observed only when the H2O2 concentration was not excessive in proportion to the amount of catalase.
Commercial formulations of Bacillus thuringiensis for control of Indian meal moth
Authors: Schesser J H
Published: January 2020

Doses of four commercial formulations and one experimental formulation of Bacillus thuringiensis Berliner were mixed with the diet used to rear colonies of the Indian meal moth Plodia interpunctella (Hübner). Indian meal moth eggs were introduced to the treated diet, and the resultant adult emergence was tabulated. The experimental formulations ranked as follows in efficacy in controlling the Indian meal moth: Dipel (50% lethal concentration [LC50], 25 mg/kg) greater than Bactospeine WP (LC50, 100 mg/kg) greater than Thuricide (LC50, 150 mg/kg) greater than IMC 90007 (LC30, 180 mg/kg) greater than Bactospeine Flowable (LC50, 440 mg/kg).
Ferric iron reduction by sulfur- and iron-oxidizing bacteria
Authors: Brock T D , Gustafson J
Published: January 2020

Acidophilic bacteria of the genera Thiobacillus and Sulfolobus are able to reduce ferric iron when growing on elemental sulfur as an energy source. It has been previously thought that ferric iron serves as a nonbiological oxidant in the formation of acid mine drainage and in the leaching of ores, but these results suggest that bacterial catalysis may play a significant role in the reactivity of ferric iron.
Isolation of strains of the cellular slime mold Dictyostelium discoideum capable of growing after a single passage in axenic medium
Authors: Williams K L
Published: January 2020

Wild-type strains of the cellular slime mold Dictyostelium discoideum grow on bacteria. Axenic strains of D. discoideum capable of growing in a simple salts-yeast extract-proteose peptone-glucose medium have been isolated from wild-type strains fo both mating types after a single passage in this medium. This result is consistent with the theory that the axenic phenotype has a simple genetic basis.
Effect of potential water pollutants and enzyme inhibitors on an automated rapid test for Escherichia coli
Authors: Moran J W , Smith T L , Witter L D
Published: January 2020

The effect of selected potential inhibitors that may be found in water or wastewater on the activity of glutamate decarboxylase (EC 4.1.1.5) from Escherichia coli was determined. Several classes of compounds inhibited the enzyme, but those expected to be most frequently encountered were the heavy metal ions, the phosphates, and possibly the sulfates. From the results, it was judged that these compounds should not adversely affect the routine usage of this enzyme in an automated rapid test for E. coli.
Reconcentration of poliovirus from sewage
Authors: Farrah S , Wallis C , Shaffer P T , Melnick J L
Published: January 2020

Virus can be adsorbed from effluents of sewage treatment plants on large-surface membranes. Subsequent elution of virus requires large volumes, which in turn requires reconcentration of virus for assay. However, reconcentration of such viral eluates on small adsorbent surfaces is difficult because certain soluble sewage components are adsorbed along with the virus on the initial virus adsorbent and are removed along with the virus by the eluent. Upon acidification of the initial eluate to reconcentrate the virus on smaller membrane surfaces, flocs are formed that interfere with the reconcentration process. To circumvent this problem, the interfering sewage components can be removed by activated carbon and ion-exchange resins. The virus is then readily reconcentrated on small membranes.
Membrane filter procedure for enumeration of Vibrio parahaemolyticus
Authors: Watkins W D , Thomas C D , Cabelli V J
Published: January 2020

A membrane filtration procedure has been developed for the enumeration of Vibrio parahaemolyticus in marine waters. Background microbial growth on the primary medium was decreased through the use of sodium cholate and copper sulfate, high pH, 3% NaCl, and an elevated incubation temperature. A series of in situ tests was employed to obviate the picking of colonies for identification; thereby, the enumeration of V. parahaemolyticus was accomplished within 30 h. Confirmation of typical colonies approached 95%. Relative to immediate plating on brain heart infusion agar spread plates, the recovery of V. parahaemolyticus cells suspended in phosphate-buffered saline or in seawater held for 24 h at 4 to 6 degrees C was about 90%. Assay variability did not exceed that expected by chance. Recoveries of V. parahaemolyticus from coastal and estuarine surface waters exceeded those obtainable by other methods examined.
Determination of growth of Sphaerotilus discophorus in the presence of manganese
Authors: Hajj H , Makemson J
Published: January 2020

Manganese interferes strongly with most chemical methods of biomass determination. However, the biomass of manganese-encrusted Sphaerotilus discophorus can be determined after removal of the MnO2 with trichloroacetic acid and oxalic acid. Evidence which indicates that manganese inhibits the heterotrophic growth of S. discophorus and that the cells only oxidize manganese late in the growth curve is presented.
Ultrastructural examination of Aeromonas cultured in the presence of organic lead
Authors: Silverberg B A , Wong P T , Chau Y K
Published: January 2020

Aeromonas sp. will methylate trimethyl lead acetate (Me3PbOAc) to volatile tetramethyl lead (Me4Pb). Examination of cultures grown in the presence of Me3PbOAc revealed no major irregularities between cells of the treated and untreated cultures. Some cells, however, showed evidence that intracytoplasmic materials had been leached from the cells. The lead-treated cells were interpreted to contain lead ions on the basis of energy-dispersive X-ray analysis.
Catalase: its effect on microbial enumeration
Authors: Martin S E , Flowers R S , Ordal Z J
Published: January 2020

The addition of catalase to the surface of selective medium plates permitted increased enumeration of physically or chemically injured (stressed) microorganisms. Catalase acted by preventing the accumulation of hydrogen peroxide in, or around, injured cells. Heat-injured Staphylococcus aureus cells had decreased catalase activity, and heat-inactivated catalase had no effect on enumeration.
Preparation of labeled staphylococcal enterotoxin A with high specific activity
Authors: Niskanen A , Lindroth S
Published: January 2020

Staphylococcal enterotoxin A (SEA) was labeled by the chloramine-T method with 125I to a specific activity of 68 to 300 muCi per mug of SEA and with 131I to specific activity of 8 to 218 muCi per mug of SEA. SEA was partially damaged and aggregated during the labeling and storage. The damage seemed not to be greatly dependent on the specific activity of labeled entertoxin. Crossed immunoelectrophoresis showed two antigenically active and three inactive components in the ascending part of the labeled enterotoxin peak during fractionation by gel chromatography. During storage at 4 degrees C, the antigenic activity of label decreased faster when labeling had been with 131I than when with 125I. The antigenic activity of labeled SEA was lowered remarkably in the ascending part of the protein peak. Greatest release of radioiodine during storage was in the same part of protein peak. According to these results, the most suitable label for radioimmunoassay is obtained from the descending part of protein peak.
Bacterial fermentation of cheese whey for production of a ruminant feed supplement rich in curde protein
Authors: Reddy C A , Henderson H E , Erdman M D
Published: January 2020

A simple and efficient process for the production of a ruminant feed supplement, rich in crude protein (defined as total N X 6.25), by bacterial fermentation of cheese whey has been developed. The lactose in unpasteurized whey is fermented to lactate acid by Lactobacillus bulgaricus at a temperature of 43 degrees C and pH 5.5. The lactic acid produced is continually neutralized with ammonia to form ammonium lactate. The fermented product is concentrated by evaporation to a solids content of about 70% and adjusted to pH 6.8 with additional ammonia. The concentrated product contains about 55% crude protein. Approximately 6 to 8% of the crude protein is derived from bacterial cells. 17% from whey proteins, and 75 to 77% from ammonium lactate. The efficiency of conversion of lactose to lactic acid usually exceeds 95%. The fermentation time is greatly reduced upon the addition of 0.2% yeast extract or 0.1% corn steep liquor as a source of growth factors. Whey containing lactose at concentrations up to 7% can be fermented efficiently, but at higher concentrations lactose is fermented incompletely. The process has been scaled up to a pilot plant level, and 40 tons of concentrated product were produced fro animal feeding trials, without ever encountering putrefactive spoilage.
Viability of lyophilized cyanobacteria (blue-green algae)
Authors: Corbett L L , Parker D L
Published: January 2020

Lyophilizatin of 13 cyanobacterial cultures belonging to seven genera was attempted in a variety of suspending substances. All organisms survived lyophilization when suspended in lamb serum. Some of the organisms could be successfully lyophilized in horse serum, beef serum, fetal bovine serum, or human ascites fluid. With the exception of Nostoc muscorium, none of the organisms survived lyophilization in skim milk medium, egg albumin medium, or Jansen salts medium.
Conidiogenesis and secondary metabolism in Penicillium urticae
Authors: Sekiguchi J , Gaucher G M
Published: January 2020

Submerged cultures of Penicillium urticae (NRRL 2159A) produced the antibiotics patulin and griseofulvin when grown in a glucose-nitrate medium. A high concentration of calcium (i.e., 68 mM) inhibited the production of both antibiotics while stimulating conidiogenesis. Conidial mutants that were defective in an early stage of conidiogenesis produced markedly less patulin, even under growth conditions that favored secondary metabolism. A mutant which lacked the ability to produce the patulin pathway metabolites m-cresol, toluquinol, m-hydroxybenzyl-alcohol, m-hydroxybenzaldehyde, gentisaldehyde, gentisyl alcohol, gentisic acid and patulin, as well as the pathway enzyme m-hydroxybenzyl-alcohol dehydrogenase, still produced yields of conidia that were equivalent to or greater than those of the parent strain. Other mutants which were blocked at later steps of the patulin pathway also produced conidia. These results indicate that patulin and the other related secondary metabolites noted above are not a prerequisite to conidiogenesis in P. urticae. Environmental and developmental factors such as calcium levels and conidiogenesis do, however, indirectly affect the production of patulin pathway metabolites.
Production of Gibberellic Acid Using a Dairy Waste as the Basal Medium
Authors: Maddox I. S. , Richert S. H.
Published: January 2020

Filtered whey has been shown to be a feasible basal medium for the production of gibberellic acid. A maximum yield of 750 mg/liter has been obtained, and the only supplement required was Mg
2+
ion at a final concentration of 10 mg/liter.
Comparison of methods for the isolation of Salmonella from imported frog legs
Authors: Andrews W H , Wilson C R , Poelma P L , Romero A
Published: January 2020

Four methods of sample preparation were compared for their relative efficiency in recovering Salmonella from imported frog legs. No significant difference (P greater than 0.10) was observed in the efficiency of submersion, blending, and stomaching methods, but rinsing recovered significantly fewer (P less than 0.01) Salmonella-positive frog legs than the other three methods. No significant difference (P less than 0.25) was observed in the number of positive frog legs recovered by selenite cystine or tetrathionate broth. Salmonella-Shigella agar, when streaked from either of these broths, gave significantly fewer (P less than 0.01) Salmonella-positive frog legs than brilliant green, bismuth sulfite, xylose lysine deoxycholate, and Hektoen-enteric agars. Use selective agars, resulted in detection of an additional 11 and 6 Salmonella-positive frog legs, respectively. A variety of serotypes, mostly uncommon, was recovered. One Salmonella serotype (6,14,24:r,i:e,n,z15), possessing a heretofore unreported antigenic formula, was isolated.
Sanitation in self-service automatic washers
Authors: Buford L E , Pickett M S , Hartman P A
Published: January 2020

The potential for microbial transfer in self-service laundry washing machines was investigated by obtaining swab samples from the interior surfaces of commercial machines and wash water samples before and after disinfectant treatment. Three disinfectants (chlorine, a quaternary ammonium product, and a phenolic disinfectant) were used. Four self-service laundry facilities were sampled, with 10 replications of the procedure for each treatment at each location. Although washers were set on a warmwater setting, the wash water temperatures ranged from 24 to 51 degrees C. The quaternary ammonium product seemed most effective, averaging a 97% microbial kill; chlorine was the second most effective, with a 58% kill, and the phenolic disinfectant was least effective, with only a 25% kill. The efficacies of the chlorine and phenolic disinfectants were reduced at low water temperatures commonly experienced in self-service laundries. Interfamily cross-contamination in self-service facilities is a potential public health problem, which is aggravated by environmental conditions, such as water temperature and the practices of the previous users of the equipment. Procedural changes in laundering are recommended, including the use of a disinfectant to maintain adequate levels of sanitation.
Confirmation of the single-step membrane filtration procedure for estimating Pseudomonas aeruginosa densities in water
Authors: Dutka B J , Kwan K K
Published: January 2020

The efficiency of two procedures, membrane filtration and most probable number, to resuscitate and enumerate Pseudomonas aeruginosa have been compared at two temperatures and varying incubation periods. Data indicate that the membrane filtration procedure using mPA or mPA medium B is more efficient than the most-probable-number procedure in estimating P. aeruginosa populations. It was also found that the specificity of the membrane filtration procedure was such that 92 to 99% of the colonies counted as P. aeruginosa were confirmed, whereas only 2.7 to 10% of the nontypical colonies were confirmed as P. aeruginosa. Furthermore, the data indicate that mPA medium B combined with a 3- to 4-day incubation period at 4.15 degrees C is slightly more specific than mPA medium and is a valid single-step procedure for the resuscitation and enumeration of P. aeruginosa from water or sewage effluent.
Lead inhibition of enzyme synthesis in soil
Authors: Cole M A
Published: January 2020

Addition of 2 mg of Pb2+/g of soil concident with or after amendment with starch or maltose resulted in 75 and 50% decreases in net synthesis of amylase and alpha-glucosidase, respectively. Invertase synthesis in sucrose-amended soil was transiently reduced after Pb2+ addition. Amylase activity was several times less sensitive to Pb2+ inhibition than was enzyme synthesis. In most cases, the rate of enzyme synthesis returned to control (Pb2+) values 24 to 48 h after the addition of Pb. The decrease in amylase synthesis was paralleled by a decrease in the number of Pb-sensitive, amylase-producing bacteria, whereas recovery of synthesis was associated with an increase in the number of amylase-producing bacteria. The degree of inhibition of enzyme synthesis was related to the quantity of Pb added and to the specific form of lead. PbSO4 decreased amylase synthesis at concentrations of 10.2 mg of Pb2+/g of soil or more, whereas PbO did not inhibit amylase synthesis at 13 mg of Pb2+/g of soil. Lead acetate, PbCl2, and PbS reduced amylase synthesis at total Pb2+ concentrations of 0.45 mg of Pb2+/g of soil or higher. The results indicated that lead is a potent but somewhat selective inhibitor of enzyme synthesis in soil, and that highly insoluble lead compounds, such as PbS, may be potent modifiers of soil biological activity.
Effect of sulfate on carbon and electron flow during microbial methanogenesis in freshwater sediments
Authors: Winfrey M R , Zeikus J G
Published: January 2020

The effect of sulfate on methane production in Lake Mendota sediments was investigated to clarify the mechanism of sulfate inhibition of methanogenesis. Methanogenesis was shown to be inhibited by the addition of as little as 0.2 mM sulfate. Sulfate inhibition was reversed by the addition of either H2 or acetate. Methane evolved when inhibition was reversed by H2 additions was derived from 14CO2. Conversely, when acetate was added to overcome sulfate inhibition, the evolved methane was derived from [2-14C]acetate. A competition for available H2 and acetate was proposed as the mechanism by which sulfate inhibited methanogenesis. Acetate was shown to be metabolized even in the absence of methanogenic activity. In the presence of sulfate, the methyl position of acetate was converted to CO2. The addition of sulfate to sediments did not result in the accumulation of significant amounts of sulfide in the pore water. Sulfate additions did not inhibit methanogenesis unless greater than 100 mug of free sulfide per ml was present in the pore water. These results indicate that carbon and electron flow are altered when sulfate is added to sediments. Sulfate-reducing organisms appear to assume the role of methanogenic bacteria in sulfate-containing sediments by utilizing methanogenic precursors.
Influence of hydrostatic pressure on the effects of the heavy metal cations of manganese, copper, cobalt, and nickel on the growth of three deep-sea bacterial isolates
Authors: Arcuri E J , Ehrlich H L
Published: January 2020

Increases hydrostatic pressure varied the 72-h growth yield of three bacterial isolates from the deep sea in the presence of heavy metal cations of Mn, Cu, Co, and Ni, depending on the bacterial isolate, the metal cation and its concentration, and the level of hydrostatic pressure. Above atmospheric, hydrostatic pressure was found to have one of the following four effects on the response of culture growth to a heavy metal cation. (i) It could be without effect; (ii) it could enhance inhibition by a metal cation; (iii) it could increase the 72-h growth yield by a metal cation; or (iv) it could protect against a growth inhibitory effect noted at a lower pressure. Possible reasons for these varied responses are discussed.
Regeneration of pleated filters used to concentrate enteroviruses from large volumes of tap water
Authors: Farrah S R , Gerba C P , Goyal S M , Wallis C , Melnick J L
Published: January 2020

Pleated cartridge filters are capable of concentrating enteroviruses from large volumes (well over 2,000 liters) of tap water. These epoxy-fiberglass filters can be regenerated if they are treated with 0.1 N NaOH or autoclaved to inactivate any contaminating virus. The regenerated filters regained their ability to concentrate viruses from water at high flow rates.
Fermentation of mucin and plant polysaccharides by strains of Bacteroides from the human colon
Authors: Salyers A A , Vercellotti J R , West S E , Wilkins T D
Published: January 2020

Ten Bacteroides species found in the human colon were surveyed for their ability to ferment mucins and plant polysaccharides ("dietary fiber"). A number of strains fermented mucopolysaccharides (heparin, hyaluronate, and chondroitin sulfate) and ovomucoid. Only 3 of the 188 strains tested fermented beef submaxillary mucin, and none fermented porcine gastric mucin. Many of the Bacteroides strains tested were also able to ferment a variety of plant polysaccharides, including amylose, dextran, pectin, gum tragacanth, gum guar, larch arabinogalactan, alginate, and laminarin. Some plant polysaccharides such as gum arabic, gum karaya, gum ghatti and fucoidan, were not utilized by any of the strains tested. The ability to utilize mucins and plant polysaccharides varied considerably among the Bacteroides species tested.
Variations in the microbial log reduction curves of irradiated cod fillets, shrimp, and their respective homogenates
Authors: Green J H , Kaylor J D
Published: January 2020

When cod (Gadus morhua morhua) and headless white shrimp (Penaeus setiferus) were gamma irradiated with a series of low-ionizing radiation doses, a "shoulder(s)" was observed in the graph (log microbial counts versus dose) in the approximate range of 25 to 75 krads. When the microbiological survivors were differentiated into total counts, proteolytic and pseudomonad-type bacteria, it was observed that the pseudomonad-type bacteria were rapidly destroyed by 25 krads and that proteolytic bacteria were destroyed at a faster rate than the rest of the microorganisms. When cod fillets and shrimp were compared with their respective homogenates and irradiated at doses of 0, 10, 20, 30, 40, 50, 60, 80, 100, 150, 200, and 300 krads, the homogenates did not exhibit the characteristic shoulders. A further experiment was designed to test surface versus uniform dispersion of microorganisms on/in gelatin disks subjects to low doses of irradiation. Differences were found that may explain the observed differences between solid food materials such as fish fillets and shrimp and their homogenates.
Effect of Temperature, Aeration, and Moisture on CO
2
Formation in Bench-Scale, Continuously Thermophilic Composting of Solid Waste
Authors: Suler D. J. , Finstein M. S.
Published: January 2020

A compost production system was employed to supply uniform material for controlled experiments of factorial design. Over a 96-h composting period, the cumulative amount of CO
2
evolved was maximal at 56 to 60°C, an aeration rate that left an O
2
residual of 10 or 18% in the exhaust gas and a moisture content of 60% wet weight. Carbon dioxide evolution was submaximal at 64°C and higher.
Tetrahydrofolate and other growth requirements of certain strains of Ruminococcus flavefaciens
Authors: Slyter L L , Weaver J M
Published: January 2020

Two strains of Ruminococcus flavefaciens were studied. Each grew in a chemically defined minimal medium containing: minerals; ammonium sulfate as a nitrogen source; amino acids as a nitrogen source, a growth promotant(s) or as both; cellobiose as an energy and carbon source; isobutyric acid, isovaleric acid, carbonic acid, and bicarbonate as additional carbon sources; and biotin, thiamine, and tetrahydrofolic acid as vitamins. Tetrahydrofolic acid (5 ng/ml) served as a replacement for rumen fluid that was required in previous media tested for the growth of these bacteria. The present bacteria differ from many of the ruminococci previously studied in that they do not require either p-amino-benzoic acid or folic acid but do require tetrahydrofolic acid for maximum growth. Dihydrofolic acid and 5-methyltetrahydrofolic acid can substitute for tetrahydrofolic acid in minimal chemically defined medium. Thus, there must be extensive metabolic interaction between the microbes inhabitating the rumen, because the R. flavefaciens isolated had complex requirements for growth and yet was among the predominant bacteria in the rumen of cattle fed a simple vitamin B-deficient, nonprotein nitrogen, high-fiber, purified diet.
Microbiological profiles of the Viking spacecraft
Authors: Puleo J R , Fields N D , Bergstrom S L , Oxborrow G S , Stabekis P D , Koukol R
Published: January 2020

Planetary quarantine requirements associated with the launch of two Viking spacecraft necessitated microbiological assessment during assembly and testing at Cape Canaveral and the Kennedy Space Center. Samples were collected from selected surface of the Viking Lander Capsules (VLC), Orbiters, (VO), and Shrouds at predetermined intervals during assembly and testing. Approximately 7,000 samples were assayed. Levels of bacterial spores per square meter on the VLC-1 and VLC-2 were 1.6 x 10(2) and 9.7 x 10(1), respectively, prior to dry-heat sterilization. The ranges of aerobic mesophilic microorganisms detected on the VO-1 and VO-2 at various sampling events were 4.2 x 10(2) to 4.3 x 10(3) and 2.3 x 10(2) to 8.9 x 10(3)/m2, respectively. Approximately 1,300 colonies were picked from culture plates, identified, lypholipized, and stored for future reference. About 75% of all isolates were microorganisms considered indigenous to humans; the remaining isolates were associated with soil and dust in the environment. The percentage of microorganisms of human origin was consistent with results obtained with previous automated spacecraft but slightly lower than those observed for manned (Apollo) spacecraft.
Continuous culture of mixed oral flora on hydroxyapatite-coated glass beads
Authors: Sudo S Z
Published: January 2020

Methods for initiating and perpetuating a culture of mixed oral flora on hydroxyapatite (HT)-coated glass beads are described. Preliminary characterization of the resultant flora showed that species common in human dental plaque were present. The composition of the flora could be manipulated by altering cultural conditions. Scanning electron micrographs demonstrated that the microbes grew in densely packed microcolonies on the surface of the HT bead. A procedure for continuous culture of colonized HT beads in glass columns is described. This technique should make it possible to utilize experimental protocols employing continuous or interrupted flow of materials.
Bacterial oxidation of polythionates: determination of tetrathionate with an ion-selective electrode
Authors: Tuovinen O H , Nicholas D J
Published: January 2020

A commercially available ion-selective electrode for nitrate was used to continuously monitor tetrathionate oxidation by Thiobacillus dentrificans. The electrode was much more sensitive to tetrathionate than to nitrate. The same electrode could also be used for the determination of trithionate.
Stability of Lactic Acid Bacteria to Freezing as Related to Their Fatty Acid Composition
Authors: Goldberg I. , Eschar L.
Published: January 2020

The viability of
Streptococcus lactis
and
Lactobacillus
sp. A-12 after freezing at -17°C for 48 h was better preserved when the cells were grown in medium supplemented with oleic acid or Tween 80 (polyoxyethylene sorbitan monooleate). A pronounced change in the cellular fatty acid composition was noted when the bacteria were grown in the presence of Tween 80. In
S. lactis
the ratio of unsaturated to saturated fatty acids increased from 1.18 to 2.55 and in
Lactobacillus
sp. A-12 it increased from 0.85 to 1.67 when Tween 80 was added to the growth medium. The antibiotic cerulenin markedly inhibited the growth of lactic acid bacteria in tomato juice (TJ) medium but had almost no effect on the growth of the bacteria in TJ medium containing Tween 80 (or oleic acid). The antibiotic inhibited markedly the incorporation of [1-
14
C]acetate but had no inhibitory effect on the incorporation of exogenous [1-
14
C]oleate (or [1-
14
C]palmitate) into the lipid fractions of lactic acid bacteria. Thus, the fatty acid composition of lactic acid bacteria, inhibited by the antibiotic cerulenin, can be modulated by exogenously added oleic acid (or Tween 80) without the concurrent endogenous fatty acid synthesis from acetate. The data obtained suggest that cerulenin inhibits neither cyclopropane fatty acid synthesis nor elongation of fatty acid acyl intermediates. The radioactivity of cells grown in the presence of [1-
14
C]oleate and cerulenin was associated mainly with cyclopropane Δ19:0, 20:0 + 20:1, and 21:0 acids. As a consequence, cerulenin caused a decrease in the ratio of unsaturated to saturated fatty acids in lactic acid bacteria as compared with cells grown in TJ medium plus Tween 80 but without cerulenin. Cerulenin caused a decrease in the viability of
S. lactis
and
Lactobacillus
sp. A-12 after freezing at -17°C for 48 h only when Tween 80 was present in the growth medium. We conclude that the sensitivity of lactic acid bacteria to damage from freezing can be correlated with specific alterations in the cellular fatty acids.
Purification and Some Biological Properties of Asparaginase from
Azotobacter vinelandii
Authors: Gaffar S. A. , Shethna Y. I.
Published: January 2020

Asparaginase was found in the soluble fraction of cells of
Azotobacter vinelandii
, and its activity remained the same during growth of the organism in a nitrogen-free medium. The specific activity and the yield of
A. vinelandii
increased twofold in the presence of ammonium sulfate. Within limits, the temperature (30 to 37°C) and pH (6.5 to 8.0) of the medium showed little effect on the levels of enzyme activity. The enzyme was purified to near homogeneity by standard methods of enzyme purification, including affinity chromatography, and had optimum activity at pH 8.6 and 48°C. The approximate molecular weight was 84,000. The apparent
K
m
value for the substrate was 1.1 × 10
-4
M. Metal ions or sulfhydryl reagents were not required for enzyme activity. Cu
2+
, Zn
2+
, and Hg
2+
showed concentration-dependent inhibition, whereas amino and keto acids had no effect on the enzyme activity. Asparaginase was stable when incubated with rat serum and ascites fluid. The enzyme had no effect on the membrane of sheep erythrocytes and did not inhibit the incorporation of radioactive precursors into deoxyribonucleic acid, ribonucleic acid, and protein in Yoshida ascites sarcoma cells. Asparaginase activity was not detected in the tumor cells.
Production of Kestoses (Fructosylsucroses) by
Phytophthora parasitica
var.
nicotianae
Authors: Hankin Lester , McIntyre John L.
Published: January 2020

The synthesis of kestoses (trisaccharides composed of two fructose units and one glucose unit) by races 0 and 1 of
Phytophthora parasitica
var.
nicotianae
is shown. The trisaccharide is found in culture filtrates of isolates grown in liquid media containing 3% sucrose. The utilization of sucrose and trisaccharide formation by the organisms over a 16-day period is described. The kestoses were identified by chemical and enzymatic analysis, and two of three possible isomers were found.
Transparent Plastic Incubator for the Anaerobic Glove Box
Authors: Balish Edward , Brown James F. , Wilkins Tracy D.
Published: January 2020

An incubator designed for use inside an anaerobic glove box is described. The incubator is made of transparent plastic material, has sliding plastic doors, and can be made in various sizes from readily available materials.
Occurrence of
Escherichia coli
in Wild Cottontail Rabbits
Authors: Kozlowski R. , Glantz P. J. , Anthony R. G.
Published: January 2020

Free-ranging cottontail rabbits (
Sylvilagus floridanus
) from two areas in central Pennsylvania were sampled over a 4-year period. Large numbers of coliforms were isolated from the intestinal tracts of these animals; in 136 of the 141 rabbits sampled,
Escherichia coli
was found to be a major component of the alimentary flora. Four serogroups (O7, O77, O73, and O103) were predominant among the isolates and were considered resistant coliflora of this species of cottontail rabbit.
Mutant of
Methylomonas methanolica
and Its Characterization with Respect to Biomass Production from Methanol
Authors: Häggström Lena
Published: January 2020

A stable variant of
Methylomonas methanolica
, with a higher temperature optimum for growth, was obtained after mutagenic treatment and selection. The mutant strain M13V has an optimum growth temperature of 35 to 37°C and a maximum at 43°C, as compared with 30 and 40°C for the wild strain. Strain M13V and
M. methanolica
have similar basic characteristics and cell composition. An extracellular polysaccharide is produced by both strains, but this property is more pronounced in strain M13V. In strain M13V the production is favored by high temperature, low growth rate, and oxygen limitation. In continuous culture of strain M13V, the polysaccharide production was partly growth associated and partly independent of the growth rate. The extracellular polysaccharide acted as a flocculating agent. A relationship between polysaccharide concentration and sedimentation rate was found. Biomass production from strain M13V is most effective at 35°C with respect to both growth rate and substrate utilization. It was found that the yield coefficient for methanol was independent of the dilution rate, whereas the yield coefficient for oxygen increased and the production coefficient for carbon dioxide decreased at increasing dilution rates. These results are discussed in connection with the polysaccharide production.
Timed-Release Capsule Method for the Detection of Salmonellae in Foods and Feeds
Authors: Sveum William H. , Hartman Paul A.
Published: January 2020

A new method was developed for the detection of injured and uninjured salmonellae in foods and feeds. The steps of pre-enrichment in a nonselective broth and selective enrichment in a selective medium were combined into a single procedure. This was achieved by the gradual release of selective agents from wax-coated gelatin capsules added at the time of inoculation of nonselective basal broths. Pre-enrichment in lactose broth was combined with selective enrichment in tetrathionate or selenite-cystine broth by using timed-release capsules containing iodine or selenite. Five different categories of foods and feeds, naturally contaminated with salmonellae, were examined to compare the efficiencies of the capsule methods with conventional procedures. Combination of the separate steps of pre-enrichment and selective enrichment into a single procedure was feasible and resulted in substantial savings of labor and materials.
Multisurface Glass Roller Bottle for Growth of Animal Cells in Culture
Authors: Knight Ernest
Published: January 2020

A multisurface glass roller bottle has been constructed for the growth of animal cells in culture. This bottle contains five concentrically placed glass cylinders that provide additional surfaces for the growth of animal cells. The bottle occupies the same space as a standard roller bottle, but it contains nine times the surface area of a standard bottle. L and HeLa cells can be grown in the bottle with cell yields 5- to 10-fold greater than in a standard bottle. L cells can be induced to produce interferon in the multisurface bottle.
Microtechnique for Most-Probable-Number Analysis
Authors: Rowe R. , Todd R. , Waide J.
Published: January 2020

A microtechnique based on the most-probable-number (MPN) method has been developed for the enumeration of the ammonium-oxidizing population in soil samples. An MPN table for a research design ([8 by 12] i.e., 12 dilutions, 8 replicates per dilution) is presented. A correlation of 0.68 was found between MPNs determined by the microtechnique and the standard tube technique. Higher MPNs were obtained with the microtechnique with increased accuracy in endpoint determinations being a possible cause. Considerable savings of time, space, equipment, and reagents are observed using this method. The microtechnique described may be adapted to other microbial populations using various types of media and endpoint determinations.
Reductions in the Toxicity of Cadmium to Microorganisms by Clay Minerals
Authors: Babich H. , Stotzky G.
Published: January 2020

The clay minerals montmorillonite and kaolinite protected bacteria, including actinomycetes, and filamentous fungi from the inhibitory effects of cadmium (Cd). Montmorillonite provided greater protection than did equivalent concentrations of kaolinite. The protective ability of the clays was correlated with their cation exchange capacity (CEC). The greater the CEC, the greater the absorbancy of exogenous Cd by the exchange complex and the greater the protection. The greater protection afforded by montmorillonite, as compared to kaolinite, was correlated with its higher CEC. Clays homoionic to Cd did not protect against exogenous Cd, as the exchange complex was already saturated with Cd. Montmorillonite homoionic to Cd was more detrimental to microbial growth than was kaolinite homoionic to Cd, as more Cd was present on and apparently desorbed from the montmorillonite.
Preparation and Activity of Immobilized
Acetobacter suboxydans
Cells
Authors: Schnarr G. Wayne , Szarek Walter A. , Jones J. K. N.
Published: January 2020

The possibility of immobilization of
Acetobacter suboxydans
cells by entrapment within polyacrylamide gels or by intercellular cross-linking with glutaral-dehyde was investigated. The oxidation of unsubstituted alditols and aldose diethyl dithioacetals by the resultant modified cells has been achieved.
Isolation of a Cellulolytic
Bacteroides
sp. from Human Feces
Authors: Betian H. G. , Linehan B. A. , Bryant M. P. , Holdeman L. V.
Published: January 2020

An anaerobic cellulolytic bacterium, identified as a
Bacteroides
sp., was present in 10
-8
g of feces from only one of five human subjects.
Unaltered Metabolism of Taurolithocholic Acid with Changes in Composition of Rat Intestinal Microflora
Authors: Kelsey M. I. , Sexton S. , Fulk G. E. , Chung K.-T.
Published: January 2020

Changes in composition of both total aerobes and anaerobes of rat intestinal microflora do not appear to affect the metabolism of taurolithocholic acid.