bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Naturally Occurring Aquatic Organic Fractions on
241
Am Uptake by
Scenedesmus obliquus (Chlorophyceae)
and
Aeromonas hydrophila (Pseudomonadaceae)
Authors: Giesy John P. , Paine Donald
Published: January 2020

Naturally occurring organics were extracted from water collected from Skinface Pond near Aiken, S.C. Organics were separated into four nominal diameter size fractions (I, >0.0183; II, 0.0183 to 0.0032; III, 0.0032 to 0.0009; IV, <0.0009 μm) by membrane ultrafiltration and introduced into
Scenedesmus obliquus
and
Aeromonas hydrophila
cultures to determine their effects on
241
Am availability for uptake. Effects on
241
Am uptake were determined in actively growing
S. obliquus
cultures after 96 h of growth and in dense cultures of nongrowing cells after 4 h. Uptake by
A. hydrophila
was determined after 4 and 24 h in actively growing cultures. All organic fractions stimulated
S. obliquus
growth, with the most pronounced effects due to larger organic fractions, whereas no apparent growth stimulation of
A. hydrophila
was observed for any organic fraction. For both long-term and short-term studies, cellular
241
Am concentration (picocuries/cell) increased with increasing
241
Am concentration for
S. obliquus
and
A. hydrophila.
Fraction IV increased
241
Am uptake by both
S. obliquus
and
A. hydrophila
during 4-h incubations. During 96-h incubations fraction I was flocculated and cosedimented, with
S. obliquus
and
A. hydrophila
cells causing an apparent increase in
241
Am uptake. Fractions II and III reduced apparent
241
Am uptake by
S. obliquus
as a result of biological dilution caused by increased algal growth due to the organics. Fraction IV caused a reduction in
241
Am uptake by
S. obliquus
not attributable to biological dilution. Organics increased
241
Am uptake by
A. hydrophila
during 4- and 24-h incubations.
A. hydrophila
also caused flocculation of fraction I during 96-h incubations.
Rapid method for detection of urea hydrolysis by yeasts
Authors: Paliwal D K , Randhawa H S
Published: January 2020

A method is described for the rapid detection of urea hydrolysis by yeasts, using the Berthelot color reaction. The results could be determined within 30 to 50 min with this method, compared with 8 to 72 h usually required with Christensen urea agar.
Lipid accumulation in an oleaginous yeast (Candida 107) growing on glucose in single-stage continuous culture
Authors: Gill C O , Hall M J , Ratledge C
Published: January 2020

Lipid accumulation of Candida 107, grown at dilution rates from 0.03 to the maximum of 0.21/h, with carbon, nitrogen, phosphate, and magnesium limitations in a chemostat, was maximal at about 40% (wt/wt) with nitrogen-limited medium at a dilution rate of 0.06/h, giving an efficiency of substrate conversion of 22 g of lipid per g of glucose consumed. At higher dilution rates the lipid content decreased. With carbon-limited growth, the highest lipid content (14%, wt/wt) was at the maximum dilution rate. High lipid contents also occurred with phosphate + nitrogen as double limitations of growth, with the lipid content of the yeast (about 35%, wt/wt) continuing to be near maximum at dilution rates also near maximum (0.17/h), thus giving the highest specific rate of lipid formation of any growth conditions (0.59 g of lipid/g of yeast per h). However, the efficiency of substrate utilization was only 5.2 g of lipid formed per 100 g of glucose consumed. The composition of the fatty acyl residues within the lipid remained constant over many weeks if the steady-state conditions remained unchanged. With carbon-limited growth, the degree of unsaturation of the fatty acids markedly decreased as the dilution rate was increased, but with nitrogen limitation the reverse trend was seen. In all cases, linoleic and oleic acids were the principal fatty acyl residues affected, and their relative proportions always varied in opposite directions. When magnesium was a limiting nutrient, there was a considerable increase in the proportion of myristic acid produced within the lipid. Neutral lipids (predominantly triglycerides) varied from 66 to 92% of the total lipid from carbon- and nitrogen-limited growth; phospholipids (varying from 2 to 25%) were highest in nitrogen-limited growth. The fatty acyl residues within each lipid fraction showed the same variations with changing growth rates.
Growth characteristics of a new methylomonad
Authors: Chen B J , Hirt W , Lim H C , Tsao G T
Published: January 2020

A methylomonad culture was isolated from pond water and examined as a potential source of single-cell protein. A medium containing magnesium sulfate, ammonium hydroxide, sodium phosphate, tap water, and methanol supported the growth of the isolate. Optimal growth conditions in batch cultures for the organism were: temperature, 30 to 33 degrees C; pH 7.1; and phosphate concentration, 0.015 M. The minimum doubling time obtained was 1.6 h. The specific growth rate in batch culture was dependent on the methanol concentration, reaching a maximum around 0.2% (wt/vol). Growth inhibition was apparent above 0.3% (wt/vol), and growth was completely inhibited above 4.6% (wt/vol) methanol. Although the inhibitory effect of formaldehyde on the specific growth rate was much greater than that of formate, the organism utilized formaldehyde, but not formate, as a sole carbon and energy source in batch cultures. The isolate was identified primarily by its inability to utilize any carbon source other than methanol and formaldehyde for growth. Although it is capable of rapid growth on methanol, the organism showed a very weak catalase activity. The amino acid content of the cells compared favorably with the reference levels for the essential amino acids specific by the Food and Agricultural Organization of the United Nations.
Thermophilic methane production from cattle waste
Authors: Varel V H , Isaacson H R , Bryant M P
Published: January 2020

Methane production from waste of cattle fed a finishing diet was investigated, using four 3-liter-working volume anaerobic digestors at 60 degrees C. At 55 degrees C a start-up culture, in which waste was the only source of bacteria, was generated within 8 days and readily adapted to 60 degrees C, where efficiency of methanogenesis was greater. Increasing the temperature from 60 to 65 degrees C tended to drastically lower efficiency. When feed concentrations of volatile solids (VS, organic matter) were increased in steps of 2% after holding for 1 months at a given concentration, the maximum concentrations for efficient fermentation were 8.2, 10.0, 11.6, and 11.6% for the retention times (RT) of 3, 6, 9, and 12 days, respectively. The VS destructions for these and lower feed concentrations were 31 to 37, 36 to 40, 47 to 49 and 51 to 53% for the 3-, 6-, 9-, and 12-day RT digestors, respectively, and the corresponding methane production rates were about 0.16, 0.18, 0.20, and 0.22 liters/day per g of VS in the feed. Gas contained 52 to 57% methane. At the above RT and feed concentrations, alkalinity rose to 5,000 to 7,700 mg of CaCo3 per liter (pH to 7.5 to 7.8), NH3 plus NH4+ to 64 to 90 mM, and total volatile acids to 850 to 2,050 mg/liter as acetate. The 3-day RT digestor was quite stable up to 8.2% feed VS and at this feed concentration produced methane at the very high rate of 4.5 liters/day per liter of digestor. Increasing the percentage of feed VS beyond those values indicated above resulted in greatly decreased organic matter destruction and methane production, variable decrease in pH, and increased alkalinity, ammonia, and total volatile acid concentrations, with propionate being the first to accumulate in large amounts. In a second experiment with another lot of waste, the results were similar. These studies indicate that loading rates can be much higher than those previously thought useful for maximizing methanogenesis from cattle waste.
Association of hydrogen metabolism with methanogenesis in Lake Mendota sediments
Authors: Winfrey M R , Nelson D R , Klevickis S C , Zeikus J G
Published: January 2020

Lake Mendota sediments were studied to determine the role of H2 in sediment methanogenesis. H2 was generally not detectable in sediment. The addition of H2 to sediment significantly increased methanogenensis. The amount of methane produced was proportional to the concentration of hydrogen added. H2 addition stimulated the reduction of CO2 to methane, but did not significantly stimulate the conversion of methanol or the methyl position of acetate to methane. Various organic compounds also stimulated sediment methanogenesis. Formate, ethanol, and glucose were shown to serve as electron donors for CO2 reduction to methane. The addition of formate to sediment resulted in H2 evolution. H2 was not deith the phenomenon of interspecies hydrogen transfer. The results indicate that hydrogen is an important intermediate and a rate-limiting factor in sediment methanogenesis.
Radiolabeling of and macromolecular syntheses in Neisseria gonorrhoeae types 1 and 4
Authors: Lim D V , James A N , Williams R P
Published: January 2020

Type 1 and type 4 cells of Neisseria gonorrhoeae were grown in a liquid medium that maintained colony type for several hours. Organisms from both types of colonies incorporated labeled glucose, as well as nucleic acid and protein precursors, into specific cellular fractions during growth in the medium. Ribonucleic acid and protein were synthesized actively by the bacteria, with incorporation of label chased by the addition of unlabeled precursors. The method can be used to label type 1 and type 4 cells of gonococci with specific isotopes for studies of metabolic and biochemical changes.
Effect of beef broth protein on the thermal inactivation of staphylococcal enterotoxin B1
Authors: Lee I C , Stevenson K E , Harmon L G
Published: January 2020

Enterotoxin B produced by Staphylococus aureus 243 in brain heart infusion broth was concentrated by dialysis against 40% polyethylene glycol (20 M), partially purified on a Sephadex G-100 column and heated at 110 degrees C in thermal death time cans. Various heating menstrua included 0.04 M Veronal buffer (pH 7.4), beef broth, and fractions of beef broth obtained by ultrafiltration or precipitation with ammonium sulfate. The toxin was assayed serologically using the microslide gel double-diffusion method. The time requiring for 90% inactivation at 110 degrees C (D110 value) obtained in buffer and in beef broth was 18 and 60 min, respectively. When the concentration of beef broth was increased fivefold, the D110 increased to 78 min. The apparent protective effect or protein was further investigated using beef broth protein obtained by precipitation with (NH4)2SO4. The D110 values were 51 and 70 min when the protein concentration in the heating menstruum was 3.8 and 7.7 mg/ml, respectively. However, when the beef broth protein was dialyzed against buffer before use as a heating menstrum, the D110 was only 39 or 41 min at comparable protein concentrations. Results indicated a dialyzable factor, whose protective effect was partially destroyed by trypsin and chymotrypsin but did not by disodium ethylenediaminetetraacetate, was involved in the protection of enterotoxin B during heating.
Isolation and molecular size of Clostridium botulinum type C toxin
Authors: Syuto B , Kubo S
Published: January 2020

A procedure is described for the purification of hemagglutinin-free Clostridium botulinum type C toxin. The toxin was purified approximately 1,000-fold from the original culture supernatant in an overall yield of 60% to a final specific toxicity of 4.4 x 10(7) minimal lethal doses/mg of protein. The toxin had a molecular weight of 141,000 and consisted of a heavy and a light chain. The molecular weights of the subunits were approximately 98,000 and 53,000. When comparing the molecular size and composition of type C toxin to that of botulinum toxins of different types, some common features may be suggested; i.e., the toxin has a molecular weight between 141,000 to 160,000 and is comprised of a heavy and a light chain linked by disulfide bonds (or bond).
Scanning electron microscopy of vaginal colonization
Authors: Larsen B , Markovetz A J , Galask R P
Published: January 2020

Changes in the appearance of the vaginal epithelium of rats during the estrous cycle were seen by scanning electron microscopy. Bacterial colonization of this tissue appeared to be influenced by these changes.
Properties of an Immobilized Pesticide-Hydrolyzing Enzyme
Authors: Munnecke Douglas M.
Published: January 2020

A bacterial enzyme(s) capable of hydrolyzing nine organophosphate insecticides was covalently bound to glass. The efficiency of this binding reaction ranged from 4 to 17%. Under continuous column operation, the immobilized enzyme(s) had an extrapolated half-life of 280 days. The specific activity of this glass-covalently bound hydrolase activity for parathion varied from 0.035 to 0.15 μmol/min per g of glass. The bound activity increased with decreasing glass particle size; however, the flow resistance also increased. Immobilized enzyme(s) kinetics were approximately 50% slower than those of the free enzyme(s), but there was no significant difference in the effect pH and temperature had on the activity of immobilized and free enzyme(s).
Form of Vitamin B
12
and Its Role in a Methanol-Utilizing Bacterium
Protaminobacter ruber
Authors: Sato Kazuyoshi , Ueda Shunsaku , Shimizu Shoichi
Published: January 2020

A methanol-utilizing bacterium,
Protaminobacter ruber
, produced a large amount of vitamin B
12
. The compounds were isolated from the cells and identified as methylcobalamin (methyl-B
12
) and adenosylcobalamin (adenosyl-B
12
) by various tests. The variation in the form of B
12
during cultivation was examined by bioautography with cellulose acetate membrane electrophoresis. Methyl-B
12
and adenosyl-B
12
were the two main B
12
compounds produced in the various phases of bacterial growth. The ratio of the amount of methyl-B
12
to total B
12
compounds was higher during the earlier phases of growth. After the logarithmic phase, adenosyl-B
12
was the predominant form. The existence of
N
5
-methyltetrahydrofolate:homocysteine transmethylase and methyl-B
12
:homocysteine transmethylase was demonstrated in cell-free extracts of
Protaminobacter ruber.
Methyl-B
12
in
P. ruber
seems to function mainly in the B
12
-dependent methionine synthetase system.
Bacteriological Investigation of Alberta Meat-Packing Plant Wastes with Emphasis on
Salmonella
Isolation
Authors: Vanderpost J. M. , Bell J. B.
Published: January 2020

The waste treatment facilities and final effluents of 11 meat-packing plants in the Province of Alberta were investigated primarily to determine the numbers of indicator bacteria and the presence of
Salmonella.
This was done to discover the efficiency of the treatment systems presently in operation in reducing bacterial numbers and to establish the need for disinfection and for bacterial standards for these effluents. Data obtained showed that the final effluents were of very poor quality bacteriologically, with numbers of indicator organisms comparable to those found in raw sewage. Primary treatment facilities were ineffective in reducing the numbers of these bacteria. The secondary treatment facility investigated achieved greater than a 99% reduction of indicator bacteria.
Salmonella
were isolated from the final effluents of 78% of the plants, including the plant using secondary treatment. In total, 21
Salmonella
serotypes were isolated.
Salmonella
isolates were not antibiotic resistant, but certain coliform and fecal coliform isolates demonstrated resistance to chloramphenicol, tetracycline, and ampicillin.
Evaluation of Recovery Methods to Detect Coliforms in Water
Authors: Bissonnette G. K. , Jezeski J. J. , McFeters G. A. , Stuart D. G.
Published: January 2020

Various recovery methods used to detect coliforms in water were evaluated by applying the membrane filter chamber technique. The membrane filter chambers, containing pure-culture suspensions of
Escherichia coli
or natural suspensions of raw sewage, were immersed in the stream environment. Samples were withdrawn from the chamber at regular time intervals and enumerated by several detection methods. In general, multiple-tube fermentation techniques gave better recovery than plating or membrane filtration procedures. The least efficient method of recovery resulted when using membrane filtration procedures, especially as the exposure period of the organisms to the stream environment increased. A 2-h enrichment on a rich, nonselective medium before exposure to selective media improved the recovery of fecal coliforms with membrane filtration techniques. Substantially enhanced recoveries of
E. coli
from pure-culture suspensions and of fecal coliforms from raw-sewage suspensions were observed when compared with recoveries obtained by direct primary exposure to selective media. Such an enrichment period appears to provide a nontoxic environment for the gradual adjustment and repair of injured cells.
Modified Radioimmunoassay Determination for Staphylococcal Enterotoxin B in Foods
Authors: Pober Zalmon , Silverman Gerald J.
Published: January 2020

The sensitivity of solid-phase radioimmunoassay for the measurement of staphylococcal enterotoxin B (SEB) in foods was decreased by food constituents that react with rabbit anti-SEB with an equivalency of over 2 ng/ml. This activity was minimized by a conditioning step for anti-SEB and by removal of interfering compounds in the sample by extraction. The assay was a sequential solid-phase radioimmunoassay technique in which polystyrene test tubes were initially incubated with antisera and then with bovine serum albumin. The tubes were then conditioned with either a centrifuged aqueous cheese extract or, equally effective, reconstituted nonfat dry milk for 16 h at 4°C. Samples of milk or heat-treated and CHCl
3
-extracted cheese or chicken salad slurries were incubated in the assay tubes for 6 h at 37°C. The samples were replaced by
125
I-labeled SEB and incubated for a further 2 to 4 h before the contents were removed and the tubes were washed and counted. A buffer solution containing known concentrations of toxin served as standards for assaying SEB in the food extracts. The entire assay can be accomplished within 24 h with a sensitivity of 1 ng/ml in milk and in the cheese extract or 1.3 ng/ml in the chicken salad extract.
Continuous Open Flow-Through System as a Model for Oil Degradation in the Arctic Ocean
Authors: Horowitz Amikam , Atlas Ronald M.
Published: January 2020

A continuous flow-through system incubated in situ was used to model oil biodegradation in Arctic coastal waters. High numbers of oil-degrading microorganisms were found in the Arctic coastal waters examined in this study. The microbial community underlying oil slicks increased and showed a population shift to a greater percentage of hydrocarbon-utilizing microorganisms. Microbial populations and oil biodegradation were increased by the addition of nitrogen and phosphorus. Both abiotic and biodegradative losses were lower than expected, perhaps due to the unusually harsh, ice-dominated Arctic summer, during which these tests were conducted. Chromatographic and spectrometric analyses showed that residual oils contained similar percentages of individual components and classes of hydrocarbons, regardless of the amount of degradation, indicating that most components of the oil were being degraded at similar rates.
Resistance of Cysts of Amoebae to Microbial Decomposition
Authors: Barrett R. A. , Alexander M.
Published: January 2020

Cyst walls of
Acanthamoeba rhysodes, A. palestinensis, A. castellanii
, and one other strain of
Acanthamoeba
contain 36 to 45% protein and 20 to 34% carbohydrate. More than half of the protein in the walls of
A. palestinensis, A. castellanii
and
Acanthamoeba
sp. is accessible to and hydrolyzed by protease, and 67 to 69% of the carbohydrate of
A. palestinensis
and
A. rhysodes
walls is hydrolyzed by cellulase. The extent of hydrolysis of walls of the other amoebae by these enzymes is appreciably less, and chitinase and β-1,3-glucanase have no detectable effect. Protease solubilizes 10% or less of the weight of intact cysts, and no solubilization is observed with cellulase. Walls of
A. palestinensis
are extensively degraded in soil, the activity is less with
A. rhysodes
, and little attack on the other amoebae occurs. When added to soil, the protozoa excyst and grow for short periods, the trophozoites then die, and chiefly cysts persist thereafter.
Application of Oxygen-Enriched Aeration in the Conversion of Glycerol to Dihydroxyacetone by
Gluconobacter melanogenus
IFO 3293
Authors: Flickinger M. C. , Perlman D.
Published: January 2020

Gluconobacter melanogenus
3293 converts glycerol to dihydroxyacetone(DHA) during exponential growth on a yeast extract-phosphate medium at pH 7. The efficiency of this conversion in 25-liter batch fermentations has been found to increase over threefold, when oxygen tension is controlled by increasing the partial pressure of oxygen in the aeration. Conversion of glycerol to DHA does not occur under oxygen-limited fermentation conditions. When the dissolved oxygen tension was maintained at 0.05 atmospheres (using oxygen-enriched air), quantitative conversion of up to 100 g of glycerol/liter to DHA was obtained in 33 h. The amount of glycerol converted can be increased without increasing impeller speed or aeration rate. This increase is not the result of increased production of cell mass. The specific conversion of glycerol to DHA increased from 12.2 g of DHA/g of cell mass at the point of maximum conversion to 35.8 with oxygen enrichment. This increased specific production occurred even though the specific growth rate during the period of oxygen enrichment decreased from 0.23 to 0.06/h.
Production of the Tremorgenic Mycotoxins Verruculogen and Fumitremorgin B by
Penicillium piscarium
Westling
Authors: Gallagher R. T. , Latch G. C. M.
Published: January 2020

The tremorgenic mycotoxins verruculogen and fumitremorgin B were isolated from
Penicillium piscarium
Westling. The coexistence of these tremorgens in culture has previously been reported for one other unrelated fungal species,
Aspergillus caespitosus
Raper and Thom, and lends further support to the suggestion that the tremorgens have a common biosynthetic origin.
Simple Procedure for Large-Scale Assays for Chick Interferon
Authors: Viehhauser Günter
Published: January 2020

Details are given of a simple and rapid method for the determination of chick interferon concentrations, using the Cooke microtiter system. The reliability of the result of this assay was examined by multiple determinations and by comparison with the results of another known assay procedure. A comparison of the relative time and cost of performing the two assays is also given.
Internal Standards for Gas Chromatographic Analysis of Metabolic End Products from Anaerobic Bacteria
Authors: Mayhew J. W. , Gorbach S. L.
Published: January 2020

2-Methylpentanoic acid and benzoic acid are suggested for use as routine internal standards for gas chromatographic analysis of microbial end products.
Mannitol oxidation in two Micromonospora isolates and in representative species of other actinomycetes
Authors: Mehta R J , Fare L R , Shearer M E , Nash C H
Published: January 2020

Mannitol kinase and mannitol-1-phosphate dehydrogenase activities were detected in two Micromonospora isolates. The presence of these enzyme activities indicates that mannitol is catabolized first to mannitol-1-phosphate and then to fructose-6-phosphate. Mannitol-oxidizing enzymes were also surveyed in representative species of four other genera of actinomycetes. Mannitol-1-phosphate dehydrogenase was detected in cell-free extracts of Streptomyces lactamdurans. In contrast, cell-free extracts of Mycobacterium smegmatis, Nocardia erythrophila, Streptomyces lavendulae, and Actinoplanes missouriensis contained mannitol dehydrogenase activity but no detectable mannitol-1-phosphate dehydrogenase activity. The mannitol dehydrogenase activities in the latter species support the operation of a pathway for catabolism of mannitol that involves the oxidation of mannitol to fructose, followed by phosphorylation to fructose-6-phosphate.
Use of an axenic medium for differentiation between pathogenic and nonpathogenic Naegleria fowleri isolates
Authors: De Jonckheere J
Published: January 2020

Growth in an axenic medium composed by Chang (3rd Int. Congr. Parasitol. Munich Abstr. ICPIII 1:187-188, 1974) allowed separation of pathogenic from nonpathogenic Naegleria fowleri strains, since only the former show luxuriant growth in this medium. On the basis of these results, this medium was used in early screening for virulent Naegleria isolates. During an extensive ecological study, data were obtained on 102 Naegleria strains. Twenty of these strains grew luxuriantly in this liquid medium. Seventeen of them were tested by intranasal instillation in mice, and all proved to be highly pathogenic. Strains showing only moderate growth or no growth at all in this axenic medium were found to be nonpathogenic for mice. Moreover, it was found that using this medium in the early stage of Naegleria sampling favors isolation of pathogenic strains in mixtures of Naegleria. During these experiments, further evidence was obtained that thermal polluted waters are the main origin of N. fowleri in the environment.
Muramic acid as a measure of microbial biomass in estuarine and marine samples
Authors: King J D , White D C
Published: January 2020

Muramic acid, a component of the muramyl peptide found only in the cell walls of bacteria and blue-green algae, furnishes a measure of detrital or sedimentary procaryotic biomass. A reproducible assay involving acid hydrolysis, preparative thin-layer chromatographic purification, and colorimetric analysis of lactate released from muramic acid by alkaline hydrolysis is described. Comparison of semitropical estuarine detritus, estuarine muds, and sediments from anaerobic Black Sea cores showed muramic acid levels of 100 to 700 microng/g (dry weight), 34 microng/g, and 1.5 to 14.9 microng/g, respectively. Enzymatic assays of lactate from muramic acid gave results 10- to 20-fold higher. Radioactive pulse-labeling studies showed that [14C]acetate is rapidly incorporated into muramic acid by the detrital microflora. Subsequent loss of 14C, accompanied by nearly constant levels of total muramic acid, indicated active metabolism in procaryotic cell walls.
Toxicity and Mutagenicity of Hexavalent Chromium on
Salmonella typhimurium
Authors: Petrilli Fernando L. , De Flora Silvio
Published: January 2020

Four hexavalent and two trivalent chromium compounds were tested for toxicity and mutagenicity by means of the
Salmonella typhimurium
/mammalian-microsome test. All hexavalent compounds yielded a complete inhibition of bacterial growth at doses of 400 to 800 μg/plate, a significant increase of
his
+
revertant colonies at doses ranging from 10 to 200 μg, and no effect at doses of less than 10 μg. The distinctive sensitivity of the four
Salmonella
strains tested (TA1535, TA1537, TA98, and TA100) suggested that hexavalent chromium directly interacts with bacterial deoxyribonucleic acid by causing both frameshift mutations and basepair substitutions. The latter mutations, which are prevalent, are amplified by an error-prone recombinational repair of the damaged deoxyribonucleic acid. On the average, 1 μmol of hexavalent chromium yielded approximately 500 revertants of the TA100 strain, irrespective of the compound tested (sodium dichromate, calcium chromate, potassium chromate, or chromic acid). The mutagenic potency of the hexavalent metal was not enhanced by adding the microsomal fraction of rat hepatocytes, induced either with sodium barbital or with Aroclor 1254. The two trivalent compounds (chromium potassium sulfate and chromic chloride), with or without the microsomal fraction, were neither toxic nor mutagenic for the bacterial tester strains.
Alternative model and approach for determining microbial heterotrophic activities in aquatic systems
Authors: Dietz A S , Albright L J , Tuominen T
Published: January 2020

Increasing amounts of high-specific-activity tritiated organic compounds were added to samples of several natural waters such that in situ substrate concentrations might be approximated. The uptake responses by the native heterotrophic microflora suggested that (i) heterotrophic populations metabolize the added nutrients, but (ii) these responses are not necessarily a reflection of Michaelis-Menten enzyme kinetics. The uptake kinetics appeared to be due to dilution of the naturally occurring metabolite by added radioactive substrate and physiological responses of the microflora to organic enrichment.
Ambient-temperature primary nonselective enrichment for isolation of Salmonella spp. from an estuarine environment
Authors: Kaper J B , Sayler G S , Baldini M M , Colwell R R
Published: January 2020

A primary, nonselective, ambient-temperature enrichment procedure for isolation of Salmonella spp. is described. The procedure was superior to elevated-temperature selective enrichment for Salmonella when estuarine water samples were examined. Five Chesapeake Bay stations were monitored, over an 8-month period, for the presence of salmonellae. Of 72 water and sediment samples collected, 17 (23.6%) yielded Salmonella spp. Seven serotypes were identified among the isolates. A seasonal pattern was noted for the incidence of the salmonellae. A most probable number procedure, performed by membrane filtration and nonselective enrichment, yielded Salmonella most probable number indices as high as 110 per 100 g of sediment. The results suggest that new methods, such as the one described in this report, are required for isolation of human intestinal pathogens from estuaries and coastal waters.
Maintenance procedures for the curtailment of genetic instability: Xanthomonas campestris NRRL B-1459
Authors: Kidby D , Sandford P , Herman A , Cadmus M
Published: January 2020

Characteristics are described of small-colony variants of Xanthomonas campestris NRRL B-1459 which are frequently encountered when routine culture maintenance procedures are employed. In contrast to the parental type, smallcolony variants were shown to be resistant to a number of antibiotics, to acridine orange, and to phage which are virulent for the parent colony type. Sensitivity to ultraviolet radiation was similar in both colony types. A simple method for preservation of viable cells is described. The suitability of the method for providing reproducible inocula free from variant cell types is examined.
Pyrolysis gas-liquid chromatography of the genus Bacillus: effect of growth media on pyrochromatogram reproducibility
Authors: Oxborrow G S , Fields N D , Puleo J R
Published: January 2020

Pyrolysis gas-liquid chromatography was performed on dried Bacillus microorganisms to evaluate the effects of growth media. Six cultures of Bacillus and six lot numbers of Trypticase soy agar (BBL) were used to test the hypothesis that a microorganism grown on various lot numbers of the same chromatogram. Also tested was the effect of three different media on chromatogram reproduction using the same six cultures. Results show little or no differences observed between the chromatograms of the individual Bacillus spp. grown on the six lot numbers of Trypticase soy agar. When chromatograms of the three different media were compared, several differences were observed, particularly in the areas most characteristic of individual species. Pryolysis gas-liquid chromatography can be a useful tool for the characterization or identification of the genus Bacillus if the chromatographic and cultural conditions are maintained.
Klebsielleae in drinking water emanating from redwood tanks
Authors: Seidler R J , Morrow J E , Bagley S T
Published: January 2020

A survey was made of the bacteriological quality and chlorine content of 33 public and private water systems that utilize redwood storage tanks. Coliforms of the genera Klebsiella and Enterobacter were isolated from 9 of 10 private drinking water systems and from 11 of 23 water systems in state and federal parks. Total coliform counts in the private systems exceeded federal membrane filter guidelines by as much as 10-to 40-fold. Coliform counts were highest in the newer reservoirs. Factors contributing to poor water quality are: lack of automated chlorination equipment or an insufficient supply to maintain a residual, common inlet/outlet plumbing design, and lengthy average retention periods. The latter two factors contribute to improper mixing and stagnation of the water, whereas the former allows microbes to multiply on the water-soluble nutrients that leach from the wood. Wooden reservoirs exert a high chlorine demand, and 0.4 ppm of chlorine residual in the incoming tank water proves inadequate. It is suggested that specific water-soluble nutrients in redwood (and in numerous other types of botanical material) induce a natural nutritional selection for coliforms of the tribe Klebsielleae.
Simple, effective method for purifying the AS-1 cyanophage
Authors: Barkley M B , Desjardins P R
Published: January 2020

Highly infectious, purified AS-1 virus was obtained by treating virus-induced culture lysates with bentonite followed by rotary evaporation concentration and density gradient centrifugation.
Ethylene production by soil microorganisms
Authors: Considine P J , Flynn N , Patching J W
Published: January 2020

Ethylene-producing strains of Penicillium cyclopium and P. crustosum were isolated from soil. These isolates produced ethylene on a variety of carbon growth substrates including phenolic acids. The quantities of ethylene produced on the various substrates varied, and the subtrate-ethylene prosuction pattern for P. cyclopium strains differed significantly from that of P. crustosum strains.
Multiple Syringe Inoculator for Agar Plates
Authors: Kaneko Tatsuo , Holder-Franklin Maxine , Franklin Mervyn
Published: January 2020

The design and operation of a manually operated multiple syringe inoculator was described. Either 9 or 21 inoculations of constant volume could be made simultaneously. Up to 100 plates could be inoculated in 15 min with excellent reproducibility. No contact occurred between the inoculating needles and the agar surface. Construction was simple and inexpensive, with minimal maintenance.
Autoclavable Dispenser for Disposable Pipette Tips
Authors: London Sheldon A.
Published: January 2020

An autoclavable dispenser for plastic disposable pipette tips is described that allows aseptic removal of individual tips while maintaining the sterility of the remaining tips.
Production and antibacterial activity of malforming C, a toxic metabolite of Aspergillus niger
Authors: Kobbe B , Cushman M , Wogan G N , Demain A L
Published: January 2020

The production of the new mycotoxin malformin C by a solid substrate fermentation is described. Malformin C is highly toxic (mean lethal dose = 0.9 mg/kg) and exerts antibacterial activity against a variety of gram-positive and gram-negative organisms.
Glucose-1-phosphate as a selective substrate for enumeration of Bacteroides species in the rumen
Authors: Dehority B A , Grubb J A
Published: January 2020

When glucose-1-phosphate was used as the only added energy source in a selective roll tube medium, colony counts for rumen contents ranged from 17.8 to 84.8% of the total culturable count. Percentages were highest in rumen contents from sheep fed high-concentrate rations. From a total of 73 cultures isolated from glucose-1-phosphate roll rubes, only 15.1% were presumptively identified as Bacteroides species. Strains presumptively identified as Butyrivibrio, Selenomonas, Treponema, Streptococcus bovis, and Lachnospira also fermented glucose-1-phosphate. Thus, glucose-1-phosphate would not be useful as a selective substrate for isolation or enumeration of Bacteroides species from the rumen.
New species of Aspergillus producing sterigmatocystin
Authors: Rabie C J , Steyn M , van Schalkwyk G C
Published: January 2020

A number of species belonging to the genus Aspergillus were evaluated for their toxicity to ducklings and the ability to produce sterigmatocystin. Three new species capable of producing sterigmatocystin were found, namely, Aspergillus aurantio-brunneus, Aspergillus quadrilineatus, and Aspergillus ustus. All three were toxic to ducklings. The production of sterigmatocystin by Aspergillus rugulosus was confirmed, and the toxicity of Aspergillus stellatus and Aspergillus multicolor is described.
Toxic effect of water-soluble fractions of crude, refined, and weathered oils on the growth of a marine bacterium
Authors: Griffin L F , Calder J A
Published: January 2020

The water-soluble fractions of three crude and two refined oils reduced the growth rate and maximum cell density of the marine bacterium Serratia marinorubra grown in batch culture. The weathering of a crude and a refined oil was simulated in the laboratory. The water-soluble fractions remaining from this process were more toxic to S. marinorubra than were the parent unweathered oils. Increases in the magnitude of toxic effect of 3 to 30 times were observed as a function of decreasing the concentration of yeast extract in the cultures from 0.1 to 0.05 and 0.01%. The toxicity did not correlate with the concentration of total water-soluble fraction or of aromatic hydrocarbons in the water-soluble fraction. Affected cultures did not exhibit a residual toxicity after being back-inoculated into control media.
Catalase and enumeration of stressed Staphylococcus aureus cells
Authors: Flowers R S , Martin S E , Brewer D G , Ordal Z J
Published: January 2020

The effects of catalase on the enumeration of stressed (heated, reduced water activity, or freeze-dried) Staphylococcus aureus cells on several selective media were examined. The addition of catalase greatly increased the enumeration of stressed cells. The beneficial effects of catalase were most pronounced on those media least efficient in enumeration of stressed staphylococci, showing increases in enumeration of up to 1,100-fold. The effects of catalase appear to be due to the reduced ability of stressed cells to repair and form colonies in the absence of an exogenous decomposer of H2O2. Thermally stressed cells were more sensitive to H2O2 than unstressed cells. During recovery, stressed cells overcame the requirement for catalase. These findings implicate H2O2 as a factor in the failure of certain selective media to adequately enumerate stressed cells and demonstrate that the addition of catalase to these media markedly increases their productivity.
Use of Lipid Composition and Metabolism to Examine Structure and Activity of Estuarine Detrital Microflora
Authors: King John D. , White David C. , Taylor Cecile W.
Published: January 2020

Earlier studies have shown that the activity of the estuarine detrital microflora measured by various enzyme activities, muramic acid and adenosine 5′-triphosphate (ATP) content, heterotrophic potentials, and respiratory activities correlates with the incorporation of
14
C and
32
P into the microbial lipids. In this study, these lipids were reproducibly fractionated into neutral lipid, glycolipid, and phospholipid classes. Distinct differences between the active microflora of oak leaves, sweet gum leaves, and pine needles were evidenced both in the rate of lipid synthesis and in the proportions of neutral lipids, glycolipids, and phospholipids. Successional changes in the microflora of leaves incubated in a semitropical estuary, previously suggested by ATP-to-muramic acid ratios and scanning electron micrography, were reflected in changes in the proportions of
14
C in major lipid classes when analyzed from the same type of detritus. Short incubation times with
14
C gave lipid compositions rich in phospholipids that are typical for the faster-growing bacterial populations; longer incubation with
14
C gave lipid compositions richer in neutral and glycolipids, more characteristic of slower-growing eukaryotes or morphologically more complex prokaryotes. The metabolism of the lipids of the estuarine detrital microflora was examined by a pulse-chase experiment with
14
C. Glycolipids lost
14
C at a rate equal to the loss of
14
C of the slow component of muramic acid. Individual phospholipids lost
14
C from their backbone glycerol esters at different rates.
Concentration of enteroviruses from estuarine water
Authors: Farrah S R , Goyal S M , Gerba C P , Wallis C , Melnick J L
Published: January 2020

Pleated cartridge filters readily adsorb viruses in estuarine water at low pH containing aluminum chloride. Adsorbed viruses are efficiently recovered by treating filters with glycine buffer at high pH. By using these procedures, it was possible to recover approximately 70% of the poliovirus added to 400 liters of estuarine water in 3 liters of filter eluate. Reconcentration of virus in the filter eluate in small volumes that are convenient for viral assays was more difficult. Reconcentration methods described previously for eluates from filters that process tap water or treated wastewater were inadequate when applied to eluates from filters used to process estuarine water containing large amounts of organic compounds. Two methods were found to permit efficient concentration of virus in filter eluates in small volumes. In both methods, virus in 3 liters of filter eluate was adsorbed to aluminum hydroxide flocs and then recovered in approximately 150 ml of buffered fetal calf serum. Additional reductions in volume were achieved by ultrafiltration or hydroextraction. By using these procedures 60 to 80% of the virus in 3 liters of filter eluate could be recovered in a final volume of 10 to 40 ml.
Osmoregulation in symbiosis-independent mutants of Bdellovibrio bacteriovorus
Authors: Varon M , Seijffers J
Published: January 2020

Bdellovibrios capable of axenic growth grow in a cell-free medium at a rate considerably lower than that attainable in a two-membered culture with Escherichia coli. The axenic growth rate may be improved either by adjustment of the osmosity of the medium or by the addition of low concentrations of spermine.
Medium for the Selective Isolation of Members of the Genus
Pseudomonas
from Natural Habitats
Authors: Grant Michael A. , Holt John G.
Published: January 2020

A new medium was developed that was superior to four others tested in selecting for members of the genus
Pseudomonas.
Comparison of limulus amebocyte lysates and correlation with the United States Pharmacopeial pyrogen test
Authors: Wachtel R E , Tsuji K
Published: January 2020

Six limulus amebocyte lysate (LAL) preparations obtained from five different suppliers were evaluated for sensitivity, dependability, cost, convenience of use, and correlation with the United States Pharmacopeial (USP) rabbit pyrogen test method. Endotoxins from various gram-negative microorganisms were used for the evaluation. Major differences among the LAL preparations lie in the area of sensitivity. Differences, up to 100-fold, exist in the sensitivity of the various LAL preparations to the same endotoxin. The LAL tests in general were 3 to 300 times more sensitive than was the USP rabbit pyrogen test method. The LAL and the USP rabbit pyrogen test data correlated well when the endotoxin in a relatively pure and undegraded form was examined. However, large discrepancies in correlation were found when partially degraded endotoxins were compared. One LAL preparation responded to both intact and degraded endotoxin, whereas others responded only to intact endotoxin; the latter closely correlated with the febrile response of the rabbit. Therefore, proper selection of an LAL preparation is important for its application in clinical, pharmaceutical, public health, and environmental areas.
Hydrogen utilization by clostridia in sewage sludge
Authors: Ohwaki K , Hungate R E
Published: January 2020

A sporeformer morphologically different but physiologically similar to Clostridium aceticum Wieringa was isolated from sewage sludge. It used large amounts of H2 and CO2, converting them chiefly to acetic acid. Growth occurs anaerobically on yeast extract alone, but after the nutrients in yeast extract are used, growth continues at a reduced rate, supported by the conversion of the gases to acetate.
Analysis of ochratoxin B alone and in the presence of ochratoxin A, using carboxypeptidase A
Authors: Hult K , H�kby E , Gatenbeck S
Published: January 2020

A method is described for ochratoxin B analysis, which is adapted to the earlier described method of ochratoxin A analysis, using carboxypeptidase A (K. Hult and S. Gatenbeck, J. Assoc. Off. Anal. Chem. 59:128-129, 1976). The fluorescence spectra of ochratoxins A and B coincide too much to allow direct discrimination of the two compounds. A method using the differences in kinetic parameters of the enzymatic hydrolysis of the two compounds is suggested for the analysis of mixtures of the ochratoxins.
Cellulolytic cocci isolated from the cecum of guinea pigs (Cavia porcellus)
Authors: Dehority B A
Published: January 2020

Five strains of anaerobic, gram-variable cellulolytic cocci, belonging to the genus Ruminococcus, were isolated from the cecum of a guinea pig. They differed from most previously described strains of cellulolytic ruminococci as follows. (i) Lactate was the major fermentation product; lesser amounts of formate and ethanol and a trace of succinate were also produced, along with an uptake of acetate. (ii) No growth occurred at 30 degrees C; however, good growth was observed at 38 and 45 degrees C, (iii) Glucose, cellobiose, cellulose, xylose, arabinose, xylan, sucrose, and lactose were fermented by all strains. Rumen fluid was required for growth in a complete medium containing all nutrients previously found to be required by species in this genus. Limited growth occurred when rumen fluid was replaced by yeast extract, and maximum, but delayed, growth occurred when a water extract of alfalfa was added to the complete medium. No qualitative differences were found in the cell wall amino acids and sugar composition of these strains as compared to Ruminococcus flavefaciens and Ruminococcus albus; however, cell walls of the guinea pig strains appeared to contain a higher proportion of glucose.
Penetration of bacteria into meat
Authors: Gill C O , Penney N
Published: January 2020

Bacteria are confined to the surface of meat during the logarithmic phase of growth. When proteolytic bacteria approach their maximum cell density, extracellular proteases secreted by the bacteria apparently break down the connective tissue between muscle fibers, allowing the bacteria to penetrate the meat. Non-proteolytic bacteria do not penetrate meat, even when grown in association with proteolytic species.
Production and counting of spores of Clostridium chauvoei
Authors: Bagadi H O
Published: January 2020

The concentration and viability of spores produced by four different strains of Clostridium chauvoei (C. feseri) grown in a modified medium for 18 days are described. The medium yielded enough viable spores for experimental work.
Use of the Minitek system for characterizing lactobacilli
Authors: Gilliland S E , Speck M L
Published: January 2020

Incubation of inoculated substrates of the Minitek system in anaerobic GasPak jars provided a method that produced results comparable to those of conventional tubed media for characterizing species of Lactobacillus. The use of sterile mineral oil to overlay inoculated substrate disks was responsible for erroneous results.
Production of refusal factors by Fusarium strains on grains
Authors: Vesonder R F , Ciegler A , Jensen A H
Published: January 2020

Corn fermented with strains of Fusarium culmorum NRRL 3288, F. poae NRRL 3287, F. moniliforme NRRL 3197, and F. nivale NRRL 3289 at 28 degrees C for 13 days was refused when fed to 30- to 60-pound (about 13.6- to 27.2-kg) swine. Analyses of the refused corn for trichothecenes (T-2, HT-2, acetyl T-2, fusarenon-X, and vomitoxin) showed that only the corn fermented with F. culmorum contained vomitoxin. None of these five trichothecenes could be detected in the other refused corn.F. culmorum grown on rice at 28 degrees C for 13 days also produced vomitoxin.