bluuebunny/crossref_metadata_2025 huggingface dataset:
Alteration of Acrylonitrile-Methylacrylate-Butadiene Terpolymer by
Nocardia rhodochrous
and
Penicillium notatum
Authors: Antoine A. D. , Dean A. V. , Gilbert S. G.
Published: January 2020

[
14
C]Barex-210, a terpolymer of acrylonitrile, methylacrylate, and butadiene, was tested for bioconversion. Powdered samples of polymer, each specifically
14
C labeled at different carbon atoms of the polymer, were incubated with either
Nocardia rhodochrous
or
Penicillium notatum
in an enriched growth medium for various periods of time. After 6 months of incubation, the
14
C-labeled polymer was transformed from a high-molecular-weight material completely soluble in dimethyl formamide (DMF) into both a lower-molecular-weight form still soluble in DMF and a second form that was no longer soluble in DMF. The amount of
14
C-labeled carbon atoms converted into DMF-insoluble material was 8% of the backbone carbon-carbon atoms and 12% of the side-chain nitrile and acrylate atoms from the acrylonitrile-methylacrylate copolymer and 60% of the elastomer (acrylonitrile-butadiene copolymer) atoms. Metabolism of the polymer was not established from measurements of metabolic
14
CO
2
. Evolution of
14
CO
2
amounted to only 0.3, 0.6, 1.8, and 3.3% of these four fractions, respectively. Although the transformation of high-molecular-weight polymer into DMF-insoluble material was rapid in the early stages of microbial growth, the accompanying CO
2
evolution was much slower. Further evidence of polymer alteration was indicated by the infrared spectrum of the insoluble material, which showed a disappearance of the nitrile and methylacrylate peaks.
Temperature Compensation of [
U
-
14
C]Glucose Incorporation by Microbial Communities in a River with a Fluctuating Thermal Regime
Authors: Witzel Karl-Paul
Published: January 2020

In summer, the river Saar in the southwest of Germany exhibits distinct temperature fluctuations from 8°C at the source to nearly 30°C in the middle region. Temperature optima for bacterial plate counts and the uptake velocity of [
U
-
14
C]glucose by the natural microbial communities of different regions ranged from 20 to 30°C, which is significantly above the mean annual water temperature. A correlation between temperature optima and different seasons or habitats was not observed. Despite the relatively high temperature optima, the turnover time for glucose was shortest at temperatures around the mean annual water temperature, due to changes in the substrate affinity. At limiting substrate concentrations, the higher substrate affinity at lower temperatures may lead to a higher real activity at in situ temperatures, and a compensatory stabilization of uptake rates at fluctuating temperatures is possible.
Interrelationships Between Microbiological and Chemical Parameters of Sandy Beach Sediments, a Summer Aspect
Authors: Meyer-Reil L.-A. , Bölter M. , Dawson R. , Liebezeit G. , Szwerinski H. , Wolter K.
Published: January 2020

At 12 stations located in sandy beach sediments of the brackish water Kiel Fjord and Kiel Bight (Baltic Sea, FRG), variations and interrelationships of microbiological, chemical, and physicochemical parameters were monitored. Depending upon location, wide variations of a number of parameters reflecting dissolved organic and inorganic nutrients, chlorophyll
a
, microbial number, and uptake activity of glucose were measured. Whereas most of the parameters generally showed the tendency to decrease from the inner to the outer Kiel Fjord, individual parameters (oxygen, particulate nitrogen, ribose, chlorophyll
a
, glucose/fructose ratio) increased with increasing distance from the inner Kiel Fjord. Similarities in the local variation pattern demonstrated various relationships between individual parameters. Among those, dissolved organic nutrients on the one hand and inorganic nutrients on the other hand were closely linked together. Variations of organic and inorganic nutrients corresponded to variations of microbial activity and physicochemical parameters. By comparing standing stock carbon with carbon production, a microbial biomass turnover time of about 100 h was calculated. Approximately 50% of the microphytobenthos primary production was fixed by microorganisms. Daily microbial carbon production (43 mg of C per m
2
) was in the range of meiofauna carbon (35 mg of C per m
2
).
Inhibitory effects of spices on growth and toxin production of toxigenic fungi
Authors: Hitokoto H , Morozumi S , Wauke T , Sakai S , Kurata H
Published: January 2020

The inhibitory effects of 29 commercial powdered spices on the growth and toxin production of three species of toxigenic Aspergillus were observed by introducing these materials into culture media for mycotoxin production. Of the 29 samples tested, cloves, star anise seeds, and allspice completely inhibited the fungal growth, whereas most of the others inhibited only the toxin production. Eugenol extracted from cloves and thymol from thyme caused complete inhibition of the growth of both Aspergillus flavus and Aspergillus versicolor at 0.4 mg/ml or less. At a concentration of 2 mg/ml, anethol extracted from star anise seeds inhibited the growth of all the strains.
Cellulose Metabolism by the Termite Flagellate
Trichomitopsis termopsidis
Authors: Yamin Michael A.
Published: January 2020

The end products of cellulose metabolism by the trichomonad flagellate
Trichomitopsis termopsidis
from the termite
Zootermopsis
sp. were investigated by growing axenic flagellates on [
14
C]cellulose. The growth of
T. termopsidis
resulted in the release of label into the supernatant fraction of the culture fluid, and > 75% was volatile under acid conditions. The label was analyzed for
14
CO
2
and for [
14
C]volatile compounds by vacuum distillation under acid and alkaline conditions in disposable micro-distillation vessels. The distillate and undistilled culture supernatant fluid were chromatographed on cellulose thin layers to identify the labeled end product.
T. termopsidis
produced
14
CO
2
and [
14
C]acetate which accounted for 25 to 30% and 55 to 60% of the labeled end products, respectively. The ratio of label in CO
2
to acetate suggests that they are produced in equimolar amounts. No neutral volatile compounds were produced. The remaining unidentified end product (10 to 20%) was not volatile nor extractable into ether. Hydrogen was produced by
T. termopsidis
, and the cells were killed by the drug metronidazole. Enzymatic activities were found which account for these end products: pyruvate:ferredoxin oxidoreductase and hydrogenase. The results indicate that acetate is the end product of
T. termopsidis
cellulose metabolism and is available to the termite for energy metabolism and biosynthesis.
Plaquing procedure for infectious hematopoietic necrosis virus
Authors: Burke J A , Mulcahy D
Published: January 2020

A single overlay plaque assay was designed and evaluated for infectious hematopoietic necrosis virus. Epithelioma papillosum carpio cells were grown in normal atmosphere with tris(hydroxymethyl)aminomethane- or HEPES (N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid)-buffered media. Plaques were larger and formed more quickly on 1- to 3-day-old cell monolayers than on older monolayers. Cell culture medium with a 10% addition of fetal calf serum (MEM 10) or without serum (MEM 0) were the most efficient virus diluents. Dilution with phosphate-buffered saline, saline, normal broth, or deionized water reduced plaque numbers. Variations in the pH (7.0 to 8.0) of a MEM 0 diluent did not affect plaque numbers. Increasing the volume of viral inoculum above 0.15 ml (15- by 60-mm plate) decreased plaquing efficiency. Significantly more plaques occurred under gum tragacanth and methylcellulose than under agar or agarose overlays. Varying the pH (6.8 to 7.4) of methylcellulose overlays did not significantly change plaque numbers. More plaques formed under the thicker overlays of both methylcellulose and gum tragacanth. Tris(hydroxymethyl)aminomethane and HEPES performed equally well, buffering either medium or overlay. Plaque numbers were reduced when cells were rinsed after virus adsorption or less than 1 h was allowed for adsorption. Variation in adsorption time between 60 and 180 min did not change plaque numbers. The mean plaque formation time was 7 days at 16 degrees C. The viral dose response was linear when the standardized assay was used.
New Method of Producing Protoplasts of
Aureobasidium pullulans
Authors: Finkelman Malcolm A. J. , Zajic James E. , Vardanis Alex
Published: January 2020

A rapid and relatively inexpensive method for producing protoplasts of the black yeast
Aureobasidium pullulans
is described. The procedure involves anaerobic incubation with the lytic preparation Driselase.
Silica Gel Plates for Culture of Marine and Nonmarine Organisms
Authors: Bazylinski Dennis A. , Rosenberg F. A.
Published: January 2020

Marine and nonmarine species of bacteria grew well when a simplified silica gel plate preparation was used.
Bacterial Predators of
Micrococcus luteus
in Soil
Authors: Casida L. E.
Published: January 2020

Micrococcus luteus
cells died relatively rapidly when they were added to natural soil. Microscopic observation showed that the cells were being physically destroyed by bacterial predators in the soil. Two of these predators were responsible for the initial, main attack, and they were isolated. The isolates on laboratory media lysed
M. luteus
cells in a manner similar to the attacks that occurred in soil. Neither predator was obligate, however, nor were they nutritionally fastidious. One of these bacteria produced mycelium and conidia. Under nutritionally poor conditions it used slender filaments of mycelium to seek out host cells. It had at least some of the characteristics of a
Streptoverticillium
species. The other bacterium was a short, gram-negative rod that did not easily fit into any of the known groups of gram-negative bacteria. It attached to host cells, but its mechanism of lysing these cells is not known.

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Temperate coliphages: classification and correlation with habitats
Authors: Dhillon E K , Dhillon T S , Lam Y Y , Tsang A H
Published: January 2020

Temperate coliphages were recovered from sewage, mammalian feces, and lysogenic strains of Escherichia coli. A total of 32 phages of independent origin were divided into six groups by applying the criteria of host range, antigenic homology, and the ultraviolet inducibility of the prophage. The demonstration of genetic interactions in some cases has confirmed the classification scheme. Nine phages were assigned to the P2 family and 19 to the lambda family. The remaining four isolates may represent some novel phylogenetic types. Phages recovered from the lysogenic strains of E. coli were all found to be P2 related, whereas a majority of the phages recovered as cell-free plaque-forming units were assignable to the lambda family. It is proposed that the biological attributes of the phages belonging to the two principal families are reflected in the distribution patterns observed. The virions of phage HK256 show multiple tail fibers and may thus represent a "new" virion form among the temperate coliphages.
Ecology of Streptococcus faecium bacteriophage in chicken gut
Authors: Houghton S B , Fuller R
Published: January 2020

The interaction in the chick gut between Streptococcus faecium and its phage was examined. In conventional chicks, large numbers of S. faecium and phage were found in the cecum and smaller numbers were found in the anterior gut. In gnotobiotic chicks associated with S. faecium SY1 and its phage, there was no marked effect on bacterial numbers, but resistance to the phage rapidly developed. Depression of chick growth caused by S. faecium strain SY1 was partially reversed by its phage.
Development of bacterial spoilage at adipose tissue surfaces of fresh meat
Authors: Gill C O , Newton K G
Published: January 2020

Adipose tissue contains low-molecular-weight soluble substances which are utilized in preference to lipid for bacterial growth. These components are present in low concentration at the surface of adipose tissue, and the pH of the surface is high (greater than 7.0). Bacteria growing on a thin layer of agar over an adipose tissue surface utilized glucose preferentially, but this was soon exhausted in the vicinity of colonies. Amino acids were then attacked, producing malodorous substances which were detectable as spoilage odors when the cell density was about 10(6)/cm2. Growth ceased at a cell density approaching 10(8)/cm2 because of substrate limitation. Bacterial lipolytic activity is not necessary for the development of bacterial spoilage of adipose tissue.
Culture of Five Commonly Used Acid-Producing Bacteria on Banana Pulp
Authors: Aegerter Paul , Dunlap Charles
Published: January 2020

A significant fraction of the bananas and plantains produced in the humid tropics are wasted due to rapid spoilage. The use of acid-producing, anaerobic fermentation may be a safe and economical way to preserve the fruit in both large- and small-scale applications. The abilities of five commonly used, acid-producing bacteria to ferment media containing ripe or green bananas were examined. Three homofermentative bacteria,
Lactobacillus bulgaricus, Streptococcus thermophilus
, and
Streptococcus faecalis
, typically reduced the pH of a puree of ripe bananas from 4.8 to about 3.5 to 3.6 in 7 days at 37�C. Action on green bananas was similar, but the drop in pH was less pronounced. Very little gas evolved.
Lactobacillus fermentum
(formerly
Lactobacillus fermenti
) and
Leuconostoc mesenteroides
showed active gas evolution and a significant drop in pH. About twice as much gas evolved from ripe banana medium as from green bananas. The fermented purees were spongy, soft solids floating in a clear liquor. The color was medium to light creamy brown, and the odor was pleasant. Fermented products stored at room temperature retained good appearance and aroma throughout a 1-month storage test.
Mouse bioassay for Fusarium metabolites: rejection or acceptance when dissolved in drinking water
Authors: Burmeister H R , Vesonder R F , Kwolek W F
Published: January 2020

Ten metabolites of Fusarium species (butenolide, diacetoxyscirpenol, equisetin, fusaric acid, gibberellic acid, moniliformin, NRRL 6227 peptide, T-2 toxin, vomitoxin, and zearalenone) were added to the drinking water of mice to determine whether they were consumed or refused. Of the 10, only the trichothecenes--diacetoxyscirpenol, T-2 toxin, and vomitoxin--were refused. Refusal of 2 mg of the trichothecenes per liter was not enhanced by adding 100 mg of zearalenone per liter.
Microbial acetyl conjugation of T-2 toxin and its derivatives
Authors: Yoshizawa T , Onomoto C , Morooka N
Published: January 2020

The acetyl conjugation of T-2 toxin and its derivatives, the 12,13-epoxytrichothecene mycotoxins, was studied by using mycelia of trichothecene-producing strains of Fusarium graminearum, F. nivale, Calonectria nivalis, and F. sporotrichoides, T-2 toxin was efficiently converted into acetyl T-2 toxin by all strains except a T-2 toxin-producing strain of F. sporotrichoides, which hydrolyzed the substrate to HT-2-toxin and neosolaniol. HT-2 toxin was conjugated to 3-acetyl HT-2 toxin as an only product by mycelia of F. graminearum and C. nivalis, but was also resistant to conjugation by both F. nivale and F. sporotrichoides. Neosolaniol was also biotransformed selectively into 3-acetyl neosolaniol by F. graminearum. However, 3-acetyl HT-2 toxin was not acetylated by any of the strains under the conditions employed, but was hydrolyzed to HT-2 toxin by F. graminearum and F. nivale. This is the first report on the biological 3 alpha-O-acetyl conjugation of T-2 toxin and its derivatives.
Method for Testing Degree of Infectivity of
Rhizobium meliloti
Strains
Authors: Olivares Jos� , Casades�s Josep , Bedmar Eulogio J.
Published: January 2020

The infectiveness of different strains of
Rhizobium meliloti
was tested with a technique that uses the addition of tetracycline to the root medium. To stop the infection, the antibiotic was added some time after the inoculation of
Medicago sativa
plants. A coefficient of infectivity for each strain was calculated according to the number of nodules that appeared with and without the addition of the antibiotic. This method seems useful in infectivity studies and is simpler and easier to perform than the test of competence between strains.
Improved method for purification of enterotoxin from Clostridium perfringens type A
Authors: Granum P E , Whitaker J R
Published: January 2020

The purification procedure of Clostridium perfringens type A enterotoxin has been improved. The cell sonic extract was precipitated twice with ammonium sulfate, first 40% saturated to concentrate the enterotoxin and then 15% saturated. The two precipitations were followed by gel filtration on Sephadex G-100. The enterotoxin appeared to be homogeneous on 7% polyacrylamide gel electrophoresis after this three-step purification procedure, with a recovery of 56% and a 12.3-fold purification. The solubility properties at different pH values, temperatures, and ammonium sulfate concentrations are also given as basis for the purification procedure.
Preferential utilization of phenol rather than glucose by Trichosporon cutaneum possessing a partially constitutive catechol 1,2-oxygenase
Authors: Shoda M , Udaka S
Published: January 2020

A phenol-utilizing yeast, Trichosporon cutaneum POB 14, which has a partially constitutive activity of catechol 1,2-oxygenase, utilized phenol in preference to glucose in a medium containing both phenol (200 mg/liter) and glucose (0.15%) as carbon sources. The glucose consumption was not observed until the concentration of phenol decreased to around 10 mg/liter. This phenomenon was confirmed by [U-14C]glucose uptake experiments. The intracellular activities of hexokinase (EC 2.7.1.1) and catechol 1,2-oxygenase (EC 1.13.1.1) changed inversely when phenol was added during growth in the glucose medium.
Determination of staphylococcal enterotoxin A in cheddar cheese produced without starter activity
Authors: Ibrahim G F , Radford H M , Fell L R
Published: January 2020

Three variants of the chloramine-T radioiodination method were used to iodinate staphylococcal enterotoxin A with 125I. Only one method consistently produced usable labels for radioimmunoassay. The iodine incorporation was 55 to 76%; the specific activity was 3.5 to 5.5 muCi/microgram of enterotoxin, and the label was extremely stable on storage at -20 degrees C. Determinations of the enterotoxin in extracts of cheddar cheese produced without starter activity were carried out with the radioimmunoassay system and protein A as antibody immunoadsorbent. The assay buffer used in this system significantly influenced the detected levels of enterotoxin in the cheese extracts. Phosphate buffer, but not tris(hydroxymethyl)aminomethane (Tris) buffer, caused gelling of cheese extract proteins, thus resulting in an incomplete separation of free from antibody-bound 125I enterotoxin. When Tris buffer was used, the results indicated a high degree of accuracy and precision for this radioimmunoassay. The lowest detectable enterotoxin concentration in cheese extract was 0.5 ng/ml.
Staphylococcal enterotoxin production in the presence of non-enterotoxigenic staphylococci
Authors: Noleto A L , Bergdoll M S
Published: January 2020

Enterotoxigenic Staphylococcus aureus strains were grown with a non-enterotoxigenic strain in laboratory medium, in milk, and in ham. Differences in pigmentation were used to differentiate the enterotoxigenic strains from the non-enterotoxigenic ones. Enterotoxin was detectable in milk when the colony counts of the non-enterotoxigenic strain were 15 to 20 times greater than those of the enterotoxigenic ones and in ham when the ratio was 60 to 77:1. Enterotoxin was detectable in milk when the enterotoxigenic strains reached counts of 10(7) colony-forming units per ml and in ham when the counts reached 10(8) colony-forming units per ml. It may be necessary in some food poisoning outbreaks to examine many isolates (up to 50 or 60) for enterotoxin production to be able to detect the enterotoxigenic staphylococci.
Comparison of anti-Vibrio activities of potassium sorbate, sodium benzoate, and glycerol and sucrose esters of fatty acids
Authors: Beuchat L R
Published: January 2020

The effects of fatty acids and their glycerol and sucrose esters, potassium sorbate, and sodium benzoate on growth of Vibrio parahaemolyticus in laboratory media at pH 6.7 were evaluated. The minimum concentrations at which inhibition by esters of glycerol could be detected were lowest for monolaurin (5 microgram/ml) and monocaprin (40 microgram/ml); these concentrations were lower than those observed for inhibition by lauric and capric acids, respectively. Inhibitory action of sucrose caprylate was detected at 40 microgram/ml, whereas sucrose caprate was effective at 100 microgram/ml; sucrose esters of lauric, myristic, and palmitic acids were ineffective at 100 microgram/ml. Potassium sorbate and sodium benzoate inhibited growth at concentrations as low as 30 and 300 microgram/ml, respectively, and enhanced the rate of thermal inactivation of V. parahaemolyticus at slightly higher concentrations. Fatty acid esters of glycerol and sucrose offer potential as perservatives for slightly acid or alkaline low-fat foods which do not lend themselves to the full antimicrobial action of traditional food preservatives such as potassium sorbate and sodium benzoate.
Die-away kinetics of aerosolized bacteria from sprinkler application of wastewater
Authors: Teltsch B , Shuval H I , Tadmor J
Published: January 2020

A methodology for estimating, under field conditions, the microbial die-away constant (lambda) is presented. This constant may be used in predicting the aerosolized pathogenic microorganism concentrations downwind from a wastewater spray or aeration site by means of modified atmospheric diffusion equations. The mean lambda of Escherichia coli for very early morning runs was 8.8 X 10(-3)s-1, and that for afternoon runs was 6.6 X 10(-2)s-1.
Growth of
Aeromonas hydrophila
at Low Concentrations of Substrates Added to Tap Water
Authors: van der Kooij D. , Visser A. , Hijnen W. A. M.
Published: January 2020

The ability of an
Aeromonas hydrophila
isolate obtained from filtered river water to grow at low substrate concentrations was studied in batch experiments with tap water supplied with low concentrations of substrates. Growth was assessed by colony count determinations. The isolate only multiplied in the used tap water (2 to 3 mg of dissolved organic carbon per liter) after the addition of a small amount of an assimilable carbon compound.
d
-Glucose especially caused growth of the organism even at initial concentrations below 10 μg of C per liter. At initial glucose concentrations below the
K

s

value (12 μg of C per liter), generation times and yield (colony-forming units per milligram of substrate-C) were nonlinear with 1/initial glucose concentrations and initial glucose concentrations, respectively. From these observations, the maintenance coefficient
m
was calculated (
m
= 0.015 mg of glucose per mg [dry wt] per h at 12°C). At initial concentrations below the
K

s

value of starch (73 μg of C per liter), no growth was observed, but complete use of starch occurred in these situations after the addition of 10 μg of glucose-C per liter. The results of this study show that information of ecological significance may be obtained by very simple batch experiments. Moreover, the isolate studied may be used in growth experiments to assess the maximum concentration of glucose which might be present in water, particularly tap water.
Localization of a mosquito-larval toxin of Bacillus sphaericus 1593
Authors: Myers P S , Yousten A A
Published: January 2020

Cell-free wall, membrane, and cytoplasmic fractions were prepared from Bacillus sphaericus 1593, which exhibited toxic activity against larvae of the mosquito Culex pipiens var. quinquefasciatus. Breakage of 12- to 14-h cells by sonication or French pressure cell yielded toxic material which could be assayed in a standard mosquito larva bioassay. When sporulating cells of strain 1593 were fractionated, the majority of the toxic activity was localized in the cell wall rather than in the plasma membrane or cytoplasm. The toxin located in the bacterial cell wall was relatively stable, in that activity was unaffected by treatment with trypsin, pronase, CHCl3-CH3OH-water, Triton X-100, 8 M urea (30 min), heat (80 degrees C, 12 min), sonication, refrigeration, lyophilization, or freezing. Activity was destroyed by boiling for 10 min or by 0.01 N NaOH. Only about 1.0% of the activity present in purified cell walls could be recovered by a 2-h extraction with 8 M urea or 3 M guanidine hydrochloride. A comparison of the toxicity of a cell-free cell wall fraction with that of a sample consisting entirely of heat-stable spores indicated that the spore preparation was about 10 times more active.
Characterization of Benthic Microbial Community Structure by High-Resolution Gas Chromatography of Fatty Acid Methyl Esters
Authors: Bobbie Ronald J. , White David C.
Published: January 2020

Fatty acids are a widely studied group of lipids of sufficient taxonomic diversity to be useful in defining microbial community structure. The extraordinary resolution of glass capillary gas-liquid chromatography can be utilized to separate and tentatively identify large numbers of fatty acid methyl esters derived from the lipids of estuarine detritus and marine benthic microbiota without the bias of selective methods requiring culture or recovery of the microbes. The gas-liquid chromatographic analyses are both reproducible and highly sensitive, and the recovery of fatty acids is quantitative. The analyses can be automated, and the diagnostic technique of mass spectral fragmentation analysis can be readily applied. Splitless injection on glass capillary gas chromatographic columns detected by mass spectral selective ion monitoring provides an ultrasensitive and definitive monitoring system. Reciprocal mixtures of bacteria and fungi, when extracted and analyzed, showed progressive changes of distinctive fatty acid methyl esters derived from the lipids. By manipulating the environment of an estuarine detrital microbial community with antibiotics and culture conditions, it was possible to produce a community greatly enriched in eucaryotic fungi, as evidenced by scanning electron microscopic morphology. The fatty acid methyl esters from the lipids in the fungus-enriched detritus showed enrichment of the C
18
dienoic and the C
18
and C
20
polyenoic esters. Manipulation of the detrital microbiota that increased the procaryotic population resulted in an absence of large structures typical of fungal mycelia or diatoms, as evidenced by scanning electron microscopy, and a significantly larger proportion of anteiso- and isobranched C
15
fatty acid esters, C
17
cyclopropane fatty acid esters, and the
cis
-vaccenic isomer of the C
18
monoenoic fatty acid esters. As determined by these techniques, a marine settling community showed greater differences in bacterial as contrasted to microeucaryotic populations when compared with the microbial communities of benthic cores.
Enumeration of Particle-Bound and Unattached Respiring Bacteria in the Salt Marsh Environment
Authors: Harvey R. W. , Young L. Y.
Published: January 2020

Proportions of respiring bacteria determined with a 2-(
p
-iodophenyl)-3-(
p
-nitrophenyl)-5-phenyl tetrazolium chloride dye-epifluorescent technique were significantly elevated in the 300-μm surface layer of a salt marsh estuary. Almost all the detectably respiring bacteria in the particle-laden surface layer and a significant proportion in subsurface waters were attached to particles.
Decomposition of Lignocellulose by
Cyathus stercoreus
(Schw.) de Toni NRRL 6473, a “White Rot” Fungus from Cattle Dung
Authors: Wicklow Donald T. , Detroy Robert W. , Jessee B. A.
Published: January 2020

Cyathus stercoreus
(Schw.) de Toni NRRL 6473, isolated from aged and fragmented cattle dung collected from a Michigan pasture, effected substantial losses in lignin (45%) from wheat straw during a 62-day fermentation (25°C). The basidiomycete also improved wheat straw digestibility by freeing α-cellulose for enzymatic hydrolysis to glucose (230 mg of glucose per 1,000 mg of fermented residue). The rationale for selecting
C. stercoreus
in attempting to biologically modify the lignin and cellulose components in wheat straw or other gramineous agricultural residues was based on the expectation that this organism is ecologically specialized to enzymatically attack the substructures of native lignins in grasses.
Enterotoxin production and thermal resistance of Yersinia enterocolitica in milk
Authors: Francis D W , Spaulding P L , Lovett J
Published: January 2020

Three of 36 raw milk isolates of Yersinia enterocolitica produced enterotoxin in milk at 25 degrees C, but not at 4 degrees C. No strain tested could survive pasteurization.
Effects of Environmental Factors on Microbial Populations in Brackish Waters off the Southern Coast of Finland
Authors: Väätänen Pentti
Published: January 2020

The roles played by environmental factors in seasonal changes in microbial populations were investigated in the Tvärminne area, off the southern coast of Finland. Surface-layer samples were collected at 1- or 2-week intervals in 1976-78, and 14 microbiological and 10 environmental parameters were determined. Stepwise multiple regression analysis was used to explain seasonal variation in the microbiological parameters. Separate analyses were made of the data from the open-water and ice-cover periods. In analyses of data from both periods, the environmental factors included accounted for a significant proportion of the variation in the parameters for community respiration (90%) and bacterial spores (80%), and a smaller proportion (60 to 65%) of the variation in total counts of bacteria and plate counts of psychrophiles and yeasts. Lower values (40 to 55%) were obtained for the variation in the other microbiological parameters. The environmental factors with maximal contributions were organic matter, water temperature, chlorophyll
a
, and salinity, but rainfall and winds also explained part of the variation in some microbiological parameters. In the winter analysis the results differed from those obtained for the other seasons, the variation being governed by parameters indicating freshwater outflows, namely, humic matter, salinity, water temperature (positive regression coefficient), and rainfall (negative regression coefficient).
Terminal Processes in the Anaerobic Degradation of an Algal-Bacterial Mat in a High-Sulfate Hot Spring
Authors: Ward David M. , Olson Gregory J.
Published: January 2020

The algal-bacterial mat of a high-sulfate hot spring (Bath Lake) provided an environment in which to compare terminal processes involved in anaerobic decomposition. Sulfate reduction was found to dominate methane production, as indicated by comparison of initial electron flow through the two processes, rapid conversion of [2-
14
C]acetate to
14
CO
2
and not to
14
CH
4
, and the lack of rapid reduction of NaH
14
CO
3
to
14
CH
4
. Sulfate reduction was the dominant process at all depth intervals, but a marked decrease of sulfate reduction and sulfate-reducing bacteria was observed with depth. Concurrent methanogenesis was indicated by the presence of viable methanogenic bacteria and very low but detectable rates of methane production. A marked increased in methane production was observed after sulfate depletion despite high concentrations of sulfide (>1.25 mM), indicating that methanogenesis was not inhibited by sulfide in the natural environment. Although a sulfate minimum and sulfide maximum occurred in the region of maximal sulfate reduction, the absence of sulfate depletion in interstitial water suggests that methanogenesis is always severely limited in Bath Lake sediments. Low initial methanogenesis was not due to anaerobic methane oxidation.
Infection of mice by aerosols of Klebsiella pneumoniae under hyperbaric conditions
Authors: Heckly R J , Chatigny M A , Dimmick R L
Published: January 2020

Both the physical behavior of aerosols and survival of airborne Serratia marcescens in hyperbaric chambers with a helium-air mixture at 20 atm of pressure was approximately the same as in the system at ambient pressures. Exposure of mice to aerosols of Klebsiella pneumoniae at 1-, 2-, and 17-atm (ca. 101-, 203-, and 1,722-kPa) pressures of helium-oxygen mixture showed that the number of viable organisms constituting a 50% lethal dose was not significantly affected by the hyperbaric conditions.
Conjugal Transfer of Genetic Information in Group N Streptococci
Authors: McKay L. L. , Baldwin K. A. , Walsh P. M.
Published: January 2020

Streptococcus lactis
strains ML3 and C
2
O and
S. lactis
subsp.
diacetylactis
strains DRC3, 11007, and WM
4
were found to transfer lactose-fermenting ability to LM0230, an
S. lactis
C2 lactose-negative (Lac
−
) derivative which is devoid of plasmid deoxyribonucleic acid (DNA). Lactose-positive streptomycin-resistant (Lac
+
Str
r
) recombinants were found when the Lac
+
Str
s
donor was mixed with Lac
−
Str
r
LM0230 in solid-surface matings. Transduction and transformation were ruled out as the mechanism of genetic exchange in strains ML3, DRC3, 11007, and WM
4
, nor was reversion responsible for the high number of Lac
+
Str
r
recombinants. Furthermore, chloroform treatment of the donor prevented the appearance of recombinants, indicating that transfer of lactose-fermenting ability required viable cell-to-cell contact. Strain C
2
O demonstrated transduction as well as conjugation. Transfer of plasmid DNA during conjugation for all strains was confirmed by demonstrating the presence of plasmid DNA in the transconjugants by using agarose gel electrophoresis. In some instances, a cryptic plasmid was transferred in conjunction with the lactose plasmid by using strains DRC3, 11007, and WM
4
. In
S. lactis
C2 × LM0230 matings, the Str
r
marker was transferred from LM0230 to C2, suggesting conjugal transfer of chromosomal DNA. The results confirm conjugation as another mechanism of genetic exchange occurring in dairy starter cultures.
Survival of enteroviruses in rapid-infiltration basins during the land application of wastewater
Authors: Hurst C J , Gerba C P , Lance J C , Rice R C
Published: January 2020

The downward migration through soil of seeded poliovirus type 1 and echovirus type 1 and of naturally occurring enteroviruses during infiltration of sewage effluent through rapid-infiltration basins was investigated. After 5 days of flooding, the amount of seeded poliovirus type 1 that had migrated 5 to 10 cm downward through the soil profile was found to be 11% of that remaining at the initial burial depth. The amount of echovirus type 1 determined to have moved an equal distance was at least 100-fold less. Migration of naturally occurring enteroviruses during infiltration of sewage effluent through soil could not be measured with accuracy because of the possibility of virus survival from previous applications of effluent. The rate of inactivation for seeded poliovirus 1 and echovirus 1 buried in the infiltration basins ranged between 0.04 and 0.15 log10 units per day during the time when the basins were flooded. Inactivation of these same seeded virus types and of indigenous enterovirus populations in the infiltration basins during the drying portion of the sewage application cycle ranged between 0.11 and 0.52 log10 units per day. The rate of virus inactivation was dependent upon the rate of soil moisture loss. These results indicate that drying cycles during the land application of wastewater enhance virus inactivation in the soil.
Poliovirus concentration from tap water with electropositive adsorbent filters
Authors: Sobsey M D , Glass J S
Published: January 2020

Simple, reliable, and efficient concentration of poliovirus from tap water was obtained with two types of electropositive filter media, one of which is available in the form of a pleated cartridge filter (Virozorb 1MDS). Virus adsorption from tap water between pH 3.5 and 7.5 was more efficient with electropositive filters than with Filterite filters. Elution of adsorbed viruses was more efficient with beef extract in glycine, pH 9.5, than with glycine-NaOH, pH 11.0. In paired comparative studies, electropositive filters, with adsorption at pH 7.5 and no added polyvalent cation salts, gave less variable virus concentration efficiencies than did Filterite filters with adsorption at pH 3.5 plus added MgCl2. Recovery of poliovirus from 1,000-liter tap water volumes was approximately 30% efficient with both Virozorb 1MDS and Filterite pleated cartridge filters, but the former were much simpler to use. The virus adsorption behavior of these filters appears to be related to their surface charge properties, with more electropositive filters giving more efficient virus adsorption from tap water at higher pH levels.
Effect of Temperature and Retention Time on Methane Production from Beef Cattle Waste
Authors: Varel V. H. , Hashimoto A. G. , Chen Y. R.
Published: January 2020

The effect of temperature and retention time on the rate of methane production from waste of beef cattle fed a finishing diet was investigated by using continuously mixed 3-liter working volume anaerobic fermentors. The temperatures ranged from 30 to 65�C with 5�C increments between fermentors. The fermentors were fed once per day with 6% volatile solids (organic matter). Retention time for each temperature was varied from 18 to 2.5 days. After 3-volume turnovers, samples were obtained on 4 consecutive days. The highest methane production rate (liters/liter of fermentor per day) and methane yield at that rate (liters/gram of volatile solids) were 1.27 and 0.19 at 9 days and 30�C, 1.60 and 0.16 at 6 days and 35�C, 2.28 and 0.23 at 6 days and 40�C, 2.42 and 0.24 at 6 days and 45�C, 2.83 and 0.14 at 3 days and 50�C, 2.75 and 0.14 at 3 days and 55�C, 3.18 and 0.14 at 2.5 days and 60�C, and 1.69 and 0.17 at 6 days and 65�C. Volatile solids degradation at these retention times and temperatures was between 46 and 54%. The concentrations of volatile acids in the 30 to 55�C fermentors were generally below 2,000 mg/liter, with the exception of the 3-day retention time. The 60 and 65�C fermentors were usually above this level for all retention times. These studies indicate potential rates of methane production from the fermentation of untreated waste of beef cattle fed high-grain finishing diets. This information should serve as preliminary guidelines for various kinetic analyses and aid in economic evaluations of the potential feasibility of fermenting beef cattle waste to methane.
Denitrification in Low pH Spodosols and Peats Determined with the Acetylene Inhibition Method
Authors: M�ller Michael M. , Sundman Veronica , Skujinš J.
Published: January 2020

Potential denitrification rates were determined for predominantly acid (pH ≥ 3.6) horizons of forestal, miry, and agricultural soils from 22 locations in southern Finland. The acetylene inhibition method was used with nitrate-amended water-logged soils incubated in an N
2
atmosphere containing 2.5 or 5% C
2
H
2
. Complete inhibition of the reduction of N
2
O to N
2
was observed in 99.3% of the samples. The denitrification rates varied from 0.12 to 53.8 μg of N�cm
-3
�day
-1
. Correlation between denitrification rate and soil pH was highly significant:
r
= 0.84 on a volume basis, and
r
= 0.44 on a weight basis. Vegetation type and amount of soil organic matter had a minor or no effect, respectively. In spodosolized soils the rates were significantly higher for B horizons than for A horizons. These results show that denitrification can occur in acid soils.
Anaerobic degradation of pteridines and purines by intestinal organisms
Authors: Fukushima T , Nixon J C
Published: January 2020

Microorganisms located within rat cecal contents degraded or catabolized [2-14C]pteridines and [2-14C]purines under anaerobic conditions, resulting in the release of 14CO2. A saturating concentration of guanosine did not affect the rate of release of CO2 from biopterin, and, likewise, the presence of a saturating level of biopterin did not significantly alter the release of CO2 from guanosine, indicating that the catabolism of these two compounds was by different systems. Part of the catabolic organisms for guanosine were segregated in a culture dilution experiment. These catabolic activities were detected in feces of humans and various other mammals. The results are compared with previously published data on the degradation of pteridines and purines.
Thermostabilization of enteroviruses by estuarine sediment
Authors: Liew P F , Gerba C P
Published: January 2020

The effect of estuarine sediment on the thermoinactivation of poliovirus type 1 and echovirus type 1 was evaluated. Poliovirus survival was prolonged at 24 and 37 degrees C but not at 4 degrees C in the presence of sediment over the time periods observed. Further inactivation studies were performed at 50 and 55 degrees C to maximize the thermal effects, and similar protection was observed. The supernatant fluid from a mixture of seawater and sediment lacked the protective effect against thermoinactivation, suggesting that prolonged virus survival in the presence of sediment was due to adsorption to particulates. From these observations, it appears that the adsorption of enteroviruses to estuarine sediments may play a significant role in protecting them against thermoinactivation.
Influence of temperature cycling on the production of aflatoxins B1 and G1 by Aspergillus parasiticus
Authors: Lin Y C , Ayres J C , Koehler P E
Published: January 2020

The effect of temperature cycling on the relative productions of aflatoxins B1 and G1 by Aspergillus parasiticus NRRL 2999 was studied. The cycling of temperature between 33 and 15 degrees C favored aflatoxin B1 accumulation, whereas cycling between 35 and 15 degrees C favored aflatoxin G1 production. Cultures subjected to temperature cycling between 33 and 25 degrees C at various time intervals changed the relative productions of aflatoxins B1 and G1 drastically. Results obtained with temperature cycling and yeast extract-sucrose medium with ethoxyquin to decrease aflatoxin G1 production suggest that the enzyme system responsible for the conversion of aflatoxin B1 to G1 might be more efficient at 25 degrees C than at 33 degrees C. The possible explanation of the effect of both constant and cycling temperatures on the relative accumulations of aflatoxins B1 and G2 might be through the control of the above enzyme system. The study also showed that greater than 57% of aflatoxin B1, greater than 47% of aflatoxin G1, and greater than 50% of total aflatoxins (B1 plus G1) were in the mycelium by day 10 under both constant and cyclic temperature conditions.
Molds in Brined Cucumbers: Cause of Softening During Air-Purging of Fermentations
Authors: Costilow Ralph N. , Gates Karen , Lacy Melvyn L.
Published: January 2020

Softening of cucumbers in fermentations purged at high air-flow rates was caused by molds growing in the brined cucumbers, not in the brine. This conclusion is based on the following results: (i) no microorganisms were isolated in significant numbers from brines that caused softening of pasteurized brined cucumbers, (ii) no pectinolytic enzyme activities were produced in cucumber brines in the absence of cucumbers, (iii) the pickles in some air-purged fermentations became very soft without the appearance of any pectinolytic enzyme activity in the brine, (iv) mold hyphae were consistently observed in tissues of soft pickles, (v) molds consistently developed in cultures of slices of surface sterilized cucumbers taken from fermentations in which soft pickles were subsequently found, and (vi) molds belonging to the genera
Alternaria, Fusarium
, and
Mucor
isolated from slices all softened pasteurized brined cucumbers.

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Inhibition of the Anaerobic Growth of
Brochothrix thermosphacta
by Lactic Acid
Authors: Grau Frederick H.
Published: January 2020

Brochothrix thermosphacta
can grow aerobically in the presence of 210 mM
l
-lactate and anaerobically in its absence at pH values down to at least 5.5. Anaerobic growth is, however, inhibited by
l
-lactate, the concentration of undissociated lactic acid being the governing factor. Postrigor meat usually contains sufficient lactic acid to select against the anaerobic growth of
B. thermosphacta
. At least some
Lactobacillaceae
strains are more resistant to lactic acid and so their growth is favored on vacuum-packaged meat.
Characteristics of Some Lactic Acid Bacteria Used as Starter Cultures in Dry Sausage Production
Authors: Nordal John , Slinde Erik
Published: January 2020

The fermentation characteristics of two commercial (Duploferment 66 and Saga II) and five Norwegian lactic acid bacteria used in dry sausage production were compared with those of
Lactobacillus plantarum
ATCC 8014. The Norwegian strains lacked the ability to ferment mannitol, sorbitol, lactose, and
d
-(+)-raffinose and grew at 8 but not at 42°C, in contrast to the ATCC culture and the two commercial strains. The lactate dehydrogenase activity of the Norwegian strains was not stimulated by pyruvate. All strains were capable of peroxide destruction when grown in the presence of myoglobin.
Aspects of Diversity Measurement for Microbial Communities
Authors: Mills Aaron L. , Wassel Raymond A.
Published: January 2020

A useful measure of diversity was calculated for microbial communities collected from lake water and sediment samples using the Shannon index (
H
′) and rarefaction [
E
(
S
)]. Isolates were clustered by a numerical taxonomy approach in which limited (<20) tests were used so that the groups obtained represented a level of resolution other than species. The numerical value of diversity for each sample was affected by the number of tests used; however, the relative diversity compared among several sampling locations was the same whether 11 or 19 characters were examined. The number of isolates (i.e., sample size) strongly influenced the value of
H
′ so that unequal sized samples could not be compared. Rarefaction accounts for differences in sample size inherently so that such comparisons are made simple. Due to the type of sampling carried out by microbiologists,
H
′ is estimated and not determined and therefore requires a statement of error associated with it. Failure to report error provided potentially misleading results. Calculation of the variance of
H
′ is not a simple matter and may be impossible when handling a large number of samples. With rarefaction, the variance of
E
(
S
) is readily determined, facilitating the comparison of many samples.
Physiological Adaptations in Response to Environmental Stress During an N
2
-Fixing
Anabaena
Bloom
Authors: Kellar Penelope E. , Paerl Hans W.
Published: January 2020

Anabaena spiroides
has the ability to maintain intense biomass production for extensive periods in the epilimnion of a small eutrophic lake characterized by conditions shown to cause photooxidative death in a number of other phytoplankton. By the enhancement of carotenoid synthesis chlorophyll
a
was protected from photooxidation and prevented from catalyzing other photooxidative reactions within the cells. By temporally separating CO
2
and N
2
fixation, maximum utilization of photosynthetically active radiation was achieved. Because CO
2
fixation was more sensitive than N
2
fixation to a high oxygen concentration, the former was maximized during morning hours, before the afternoon buildup of dissolved oxygen. The diurnal partitioning of carbon and N
2
fixation has two additional advantages; possible competition for reductant-generating compounds is minimized, and adequate endogenous pools of carbon skeletons are assured to accept newly fixed ammonia. Hence,
Anabaena
, far from undergoing photooxidative death, appears to utilize a physiological strategy which allows optimization of radiant energy use for reductive processes and dominance of surface waters and shading of deeper phytoplankton during summer blooms.