bluuebunny/crossref_metadata_2025 huggingface dataset:
Annual Cycle of Bacterial Secondary Production in Five Aquatic Habitats of the Okefenokee Swamp Ecosystem
Authors: Murray Robert E. , Hodson Robert E.
Published: January 2020

Rates of bacterial secondary production by free-living bacterioplankton in the Okefenokee Swamp are high and comparable to reported values for a wide variety of marine and freshwater ecosystems. Bacterial production in the water column of five aquatic habitats of the Okefenokee Swamp was substantial despite the acidic (pH 3.7), low-nutrient, peat-accumulating character of the environment. Incorporation of [
3
H]thymidine into cold-trichloroacetic acid-insoluble material ranged from 0.03 to 2.93 nmol liter
−1
day
−1
) and corresponded to rates of bacterial secondary production of 3.4 to 342.2 μg of carbon liter
−1
day
−1
(mean, 87.8 μg of carbon liter
−1
day
−1
). Bacterial production was strongly seasonal and appeared to be coupled to annual changes in temperature and primary production. Bacterial doubling times ranged from 5 h to 15 days and were fastest during the warm months of the year, when the biomass of aquatic macrophytes was high, and slowest during the winter, when the plant biomass was reduced. The high rates of bacterial turnover in Okefenokee waters suggest that bacterial growth is an important mechanism in the transformation of dissolved organic carbon into the nutrient-rich bacterial biomass which is utilized by microconsumers.
Role of Penicillic Acid in the Phytotoxicity of
Penicillium cyclopium
and
Penicillium canescens
to the Germination of Corn Seeds
Authors: Keromnes Jacqueline , Thouvenot Daniel
Published: January 2020

Penicillium cyclopium
and
Penicillium canescens
cultures inhibited the germination of corn. The phytotoxic compound was isolated by solvent extraction and thin-layer chromatography on silica gel. The phytotoxin was identified as penicillic acid by mass spectrometry, nuclear magnetic resonance, and infrared spectroscopy. Gas-liquid chromatography on a capillary glass column separated the two epimeric forms of penicillic acid. The maximum production of penicillic acid was obtained with
P. cyclopium
cultures grown at 25°C. The phytotoxicity of penicillic acid was manifested by its ability to alter the germination of corn. The percent inhibition of germination was directly proportional to the logarithm of the penicillic acid concentration. Growth of the main root was reduced 50% by concentrations of 500 μg/ml.
Isolation, characterization, and serotyping of Campylobacter jejuni and Campylobacter coli from slaughter cattle
Authors: Garcia M M , Lior H , Stewart R B , Ruckerbauer G M , Trudel J R , Skljarevski A
Published: January 2020

A total of 525 specimens from 100 slaughter beef cattle were examined for the presence of Campylobacter jejuni and Campylobacter coli by direct plating and enrichment techniques. Isolates were identified by cultural, biochemical, antibiotic sensitivity, and immunofluorescence tests and further characterized with the aid of recently developed biotyping and serotyping methods. Fifty animals were positive for C. jejuni; only one was positive for C. coli. The distribution pattern of C. jejuni-positive animals, in decreasing order, was steers (55%), bulls (40%), heifers (40%), and cows (22%). Significantly higher isolation rates were obtained from the gall bladders (33%), large intestines (35%), and small intestines (31%) than from the livers (12%) or the lymph nodes (1.4%). C. jejuni isolation by the enrichment technique was 40.2% more frequent than by direct plating; 24-h enrichment resulted in 24% more isolations than 48-h enrichment. Eighty-four of 105 C. jejuni cultures were typable serologically and represented 13 serogroups. Biotype I accounted for 71% of biotyped cultures. Serogroup 7 biotype I was the most commonly encountered (24%) isolate. About one in three positive animals had C. jejuni strains representing more than one serogroup. C. jejuni serogroups encountered in slaughter cattle were similar to those commonly isolated from human sources.
beta-Glucuronidase activities of intestinal bacteria determined both in vitro and in vivo in gnotobiotic rats
Authors: Gadelle D , Raibaud P , Sacquet E
Published: January 2020

The beta-glucuronidase activities of bacterial strains isolated from the rat intestinal tract were studied both in vitro in culture media and in vivo in the intestinal contents of gnotobiotic rats. Only 50 of 407 strains tested were found to be positive in vitro. They belonged to the three genera Clostridium, Peptostreptococcus, and Staphylococcus. The in vitro-negative strains were also negative in vivo. The beta-glucuronidase activities of the beta-glucuronidase activities of the positive strains were generally greater in vivo than in vitro. The highest in vivo activities were found in the intact bacterial cells and in the soluble fractions prepared from disrupted pellets. There was a discrepancy between the activities obtained from both conventional and gnotobiotic rats harboring selected positive strains, suggesting that the main beta-glucuronidase-positive strains have not yet been isolated from the intestines of conventional rats.
Only part of the protoxin gene of Bacillus thuringiensis subsp. berliner 1715 is necessary for insecticidal activity
Authors: Wabiko H , Held G A , Bulla L A
Published: January 2020

Escherichia coli strains harboring deletion mutations of the insecticidal protoxin gene of Bacillus thuringiensis subsp. berliner 1715 were constructed. Although these strains did not produce intact protoxin, cell extracts from one of the mutants were extremely toxic to tobacco hornworm (Manduca sexta) larvae, indicating that only a part of the protoxin gene is required for insecticidal activity.
Inactivation of nuclear polyhedrosis virus (Baculovirus subgroup A) by monochromatic UV radiation
Authors: Griego V M , Martignoni M E , Claycomb A E
Published: January 2020

Monochromatic radiation at wavelengths of 290, 300, 310, and 320 nm inactivated occluded nuclear polyhedrosis virus of the Douglas-fir tussock moth, Orgyia pseudotsugata (McDunnough). Data indicate that all of the wavelengths are capable of causing virus inactivation; much greater fluences are needed for virus inactivation as the wavelength increases.
Cloning and expression in Escherichia coli of pectinase genes of Erwinia carotovora subsp. carotovora
Authors: Zink R T , Chatterjee A K
Published: January 2020

Genes coding for an endo-pectate lyase, an exo-pectate lyase, and an endopolygalacturonase of Erwinia carotovora subsp. carotovora Ecc71 were cloned in Escherichia coli HB101, using the cosmid pHC79. The products of the cloned pectinase genes paralleled their counterparts in strain Ecc71 in isoelectric mobility, mode of substrate degradation, and ability to macerate potato tuber tissue.
Isolation, chemical structure, acute toxicity, and some physicochemical properties of territrem B' from Aspergillus terreus
Authors: Peng F C , Ling K H , Wang Y , Lee G H
Published: January 2020

We have isolated a metabolite of territrem, designated territrem B', from the chloroform extract of a rice culture of Aspergillus terreus 23-1 by using the same isolation procedure as that for territrems A, B, and C. The present isolation procedure gave about 10 mg of territrem B' from 4 kg of rice culture per batch. Analysis of the high-resolution mass spectrum showed that the molecular composition of territrem B' is C29H34O10 (found, 542.2167; required, 542.200). Some results of physicochemical and acute tests are presented in this paper. Single-crystal X-ray diffractometry of territrem B' indicated that the three-dimensional structure of territrem B' has not changed significantly from that of territrem B except for the insertion of one oxygen atom into territrem B to make an additional pyron ring in the E ring. The tremorgenic activity of territrem B' is greatly reduced as tested by intraperitoneal injection in mice.
Effect of seeding during thermophilic composting of sewage sludge
Authors: Nakasaki K , Sasaki M , Shoda M , Kubota H
Published: January 2020

The effect of seeding on the thermophilic composting of sewage sludge was examined by measuring the changes in CO2 evolution rates and microbial numbers. Although the succession of thermophilic bacteria and thermophilic actinomycetes clearly reflected the effect of seeding, no clear difference was observed in the overall rate of composting or quality of the composted product.
Estimation of Campylobacter spp. in broth culture by bioluminescence assay of ATP
Authors: Ng L K , Taylor D E , Stiles M E
Published: January 2020

The luciferin-luciferase bioluminescence reaction was used to estimate cell numbers of Campylobacter jejuni and Campylobacter coli in broth cultures based on a linear relationship between cell numbers (in excess of 10(4) to 10(5] and ATP levels. The sensitivity was lower than that obtained with Escherichia coli. The calculated amount of intracellular ATP per cell of C. jejuni and C. coli ranged from 1.7 to 2.1 fg.
Cryptic plasmids in Lactobacillus strains isolated from the murine gastrointestinal tract
Authors: Lin J H , Savage D C
Published: January 2020

Ten of twenty Lactobacillus strains isolated from the gastrointestinal tracts of animals of several species contained plasmids of 80 to 90 megadaltons or less than 2.6 megadaltons in size, as analyzed by agarose gel electrophoresis. The large plasmids were found only in strains originally isolated from the keratinized epithelium of the murine stomach.
Persistently infected cultures as a source of hepatitis A virus
Authors: Simmonds R S , Szücs G , Metcalf T G , Melnick J L
Published: January 2020

Primary African green monkey kidney, continuous African green monkey kidney cell line BS-C-1, and buffalo green monkey kidney cultures were infected with a uniform inoculum of hepatitis A virus (HAV). Although both the cell line BS-C-1 and primary African green monkey kidney cultures produced useful amounts of virus, HAV was detected earlier and in greater quantities in primary African green monkey kidney cultures. A persistently infected primary African green monkey kidney culture was developed. The influence of incubation time (4 to 40 days) and concentration (2 to 15%) of fetal calf serum in the maintenance medium on production of HAV by this culture was examined. An incubation period of 24 to 28 days was found to be optimal; reducing this period led to decreased yields of HAV. No significant difference in the amount of HAV produced was observed with differing concentrations of fetal calf serum. Three different methods of extraction and the effect of multiple extractions on the recovery of HAV from cell lysates were examined. Sonication was a critical factor. Two extractions yielded more than 90% recoverable virus. Yields in excess of 10(11) physical particles of HAV per 850-cm2 roller bottle were routine. The total yield could be increased by concentrating the HAV present in spent maintenance medium by using bentonite or organic flocculation.
Anaerobic Growth and Denitrification among Different Serogroups of Soybean Rhizobia
Authors: van Berkum Peter , Keyser Harold H.
Published: January 2020

We screened soybean rhizobia originating from three germplasm collections for the ability to grow anaerobically in the presence of NO
3
−
and for differences in final product formation from anaerobic NO
3
−
metabolism. Denitrification abilities of selected strains as free-living bacteria and as bacteroids were compared. Anaerobic growth in the presence of NO
3
−
was observed in 270 of 321 strains of soybean rhizobia. All strains belonging to the 135 serogroup did not grow anaerobically in the presence of NO
3
−
. An investigation with several strains indicated that bacteria not growing anaerobically in the presence of NO
3
−
also did not utilize NO
3
−
as the sole N source aerobically. An exception was strain USDA 33, which grew on NO
3
−
but failed to denitrify. Dissimilation of NO
3
−
by the free-living cultures proceeded without the significant release of intermediate products. Nitrous oxide reductase was inhibited by C
2
H
2
, but preceding steps of denitrification were not affected. Final products of denitrification were NO
2
−
, N
2
O, or N
2
; serogroups 31, 46, 76, and 94 predominantly liberated NO
2
−
, whereas evolution of N
2
was prevalent in serogroups 110 and 122, and all three were formed as final products by strains belonging to serogroups 6 and 123. Anaerobic metabolism of NO
3
−
by bacteroid preparations of
Bradyrhizobium japonicum
proceeded without delay and was evident by NO
2
−
accumulation irrespective of which final product was formed by the strain as free-living bacteria. Anaerobic C
2
H
2
reduction in the presence of NO
3
−
was observed in bacteroid preparations capable of NO
3
−
respiration but was absent in bacteria that were determined to be deficient in dissimilatory nitrate reductase.
Virus persistence in groundwater
Authors: Yates M V , Gerba C P , Kelley L M
Published: January 2020

More than 50% of the outbreaks of waterborne disease in the United States are due to the consumption of contaminated groundwater. An estimated 65% of the cases in these outbreaks are caused by enteric viruses. Little, however, is known about the persistence of viruses in groundwater. The purpose of this study was to determine whether measurable chemical and physical factors correlate with virus survival in groundwater. Groundwater samples were obtained from 11 sites throughout the United States. Water temperature was measured at the time of collection. Several physical and chemical characteristics, including pH, nitrates, turbidity, and hardness, were determined for each sample. Separate water samples were inoculated with each of three viruses (poliovirus 1, echovirus 1, and MS-2 coliphage) and incubated at the in situ groundwater temperature; selected samples were also incubated at other temperatures. Assays were performed at predetermined intervals over a 30-day period to determine the number of infective viruses remaining. Multiple regression analysis revealed that temperature was the only variable significantly correlated with the decay rates of all three viruses. No significant differences were found among the decay rates of the three viruses, an indication that MS-2 coliphage might be used as a model of animal virus survival in groundwater.
Antibiotic-resistant bacteria in wild primates: increased prevalence in baboons feeding on human refuse
Authors: Rolland R M , Hausfater G , Marshall B , Levy S B
Published: January 2020

We examined three groups of wild baboons (Papio cynocephalus) in Amboseli National Park, Kenya, to determine the prevalence of aerobic antibiotic-resistant fecal bacteria in nonhuman primates with and without contact with human refuse. Using standard isolation and replica plating techniques, we found only low numbers of antibiotic-resistant gram-negative enteric bacteria in two groups of baboons leading an undisturbed existence in their natural habitat and having limited or no contact with humans. However, resistance was significantly higher among enteric bacteria from the third group of baboons living in close proximity to a tourist lodge and having daily contact with unprocessed human refuse. Conjugation studies and analysis of the cell DNA by gel electrophoresis showed that in many cases resistance was plasmid-borne and transferable. These data suggest that wild nonhuman primates in frequent contact with human debris have a higher proportion of antibiotic-resistant enteric bacteria than do conspecifics without this contact. The findings further suggest that such groups of wild animals may constitute a heretofore overlooked source of antibiotic resistance in the natural environment.
Effects of bentonite clay solids on poliovirus concentration from water by microporous filter methods
Authors: Sobsey M D , Cromeans T
Published: January 2020

To determine whether suspended solids interfere with enteric virus recovery from water by microporous filter methods, the effects of bentonite clay solids at a concentration of 10 nephelometric turbidity units on the recovery of poliovirus type 1 from seeded, activated carbon-treated, filtered tap water were studied. Volumes (500 ml) of virus-laden water at pH 5.5 or 7.5, with and without 50 mM MgCl2, were filtered through 47-mm-diameter, electropositive (Virosorb 1MDS) and electronegative (Filterite) filters that had been pretreated with Tween 80 to minimize direct virus adsorption to filter surfaces. Bentonite solids enhanced virus retention on both types of filters, even under conditions in which viruses were not solids associated. However, bentonite solids also interfered with elution of retained viruses when eluting with 0.3% beef extract-50 mM glycine (pH 9.5). Under some conditions, overall virus recoveries were lower from water with bentonite solids than from solids-free control water. The results of this study indicate that clay turbidity can interfere somewhat with virus recovery by current microporous filter methods.
Kinetic profiles of diacetoxyscirpenol and two of its metabolites in blood serum of pigs
Authors: Bauer J , Bollwahn W , Gareis M , Gedek B , Heinritzi K
Published: January 2020

Orally administered diacetoxyscirpenol (2 mg/kg of body weight) was rapidly absorbed into the blood serum of pigs; within 1 h, the highest amounts of diacetoxyscirpenol (9.6 to 21.9 ng/ml) were detected. Two metabolites of diacetoxyscirpenol were identified by gas chromatography-mass spectroscopy as monoacetoxyscirpenol and scirpenetriol. The three trichothecenes were present in the blood serum of pigs for only 24 h, indicating a rapid metabolism of these compounds.
Copper-binding characteristics of exopolymers from a freshwater-sediment bacterium
Authors: Mittelman M W , Geesey G G
Published: January 2020

Copper-binding activity by exopolymers from adherent cells of a freshwater-sediment bacterium was demonstrated by a combination of equilibrium dialysis and flameless atomic absorption spectrometry. Crude, cell-free exopolymer preparations containing protein and polysaccharide components bound up to 37 nmol of Cu per mg (dry weight). A highly purified exopolysaccharide preparation bound up to 253 nmol of Cu per mg of carbohydrate. The conditional stability constant for the crude exopolymer-Cu complex was 7.3 X 10(8). This value was similar to those obtained for Cu complexes formed with humic acids and xanthan, an exopolysaccharide produced by Xanthomonas campestris. Studies conducted at copper concentrations, pHs, and temperatures found in sediments from which the bacterium was isolated indicated that the exopolymers were capable of binding copper under natural conditions.
Image analysis method for the rapid counting of Saccharomyces cerevisiae cells
Authors: Costello P J , Monk P R
Published: January 2020

An image analysis system which incorporates a microscope, video camera, monitor, and Apple computer and which uses image area to count Saccharomyces cerevisiae cells is described and evaluated. Yeast cell suspensions of densities of up to 100 X 10(6) cells per ml can be counted when viewed in the counting chamber of a hemacytometer. The yeast image area measured depends upon the light intensity used to illuminate the yeast cells, the sharpness of the image focused on the monitor, and the grey level selected when scanning the digitized image on the monitor of the Apple computer, all of which can be controlled. The image area also depends upon the yeast strain and medium in which the culture is grown, but it is not affected by the concentration of sugar or ethanol in which the yeast cells are suspended. Yeast growth measured by image analysis can be calibrated to give results similar to those obtained with hemacytometer counting. Yeast cells can be counted in the presence of high cell densities of bacteria by adjusting the grey level at which the digitized image is scanned.
Biodegradation of [14C]phenol in secondary sewage and landfill leachate measured by double-vial radiorespirometry
Authors: Deeley G M , Skierkowski P , Robertson J M
Published: January 2020

Double-vial radiorespirometry was used to estimate the biodegradation rates of 14C-labeled phenol in a landfill leachate and a secondary treated domestic wastewater. Rates were found to be comparable for each material at each of the three concentrations tested. Sewage microorganisms immediately began biodegrading the [14C]phenol; landfill leachate microorganisms required a lag period before maximum biodegradation of the [14C]phenol. The apparent rate of [14C]phenol biodegradation was 2.4 times faster in the sewage than in the landfill leachate. Double-vial radiorespirometry was shown to be an effective method for screening biodegradation rates in aquifers.
Metabolism of aflatoxin B1 by rat hepatic microsomes induced by polyhalogenated biphenyl congeners
Authors: Halvorson M R , Phillips T D , Safe S H , Robertson L W
Published: January 2020

The metabolism of aflatoxin B1 to aflatoxins M1 and Q1 by rat liver microsomes from animals pretreated with polychlorinated or polybrominated biphenyl congeners depended on the structure of the halogenated biphenyl inducers. Microsomes from rats treated with phenobarbital (PB) or halogenated biphenyls that exhibit PB-type activity preferentially enhanced the conversion of aflatoxin B1 to aflatoxin Q1. In contrast, microsomes from rats treated with 3-methylcholanthrene (MC) or halogenated biphenyls that exhibit MC-type induction activity increased the metabolism of aflatoxin B1 to aflatoxin M1. The coadministration of PB and MC produced microsomes that exhibited both types of induction activity (mixed type) in catalyzing the oxidative metabolism of diverse xenobiotic agents. However, PB-plus-MC-induced hepatic microsomes from immature male Wistar rats preferentially increased the metabolism of aflatoxin B1 to aflatoxin M1 but did not enhance the conversion of aflatoxin B1 to aflatoxin Q1. Comparable results were observed with microsomes from rats pretreated with halogenated biphenyls classified as mixed-type inducers; moreover, in some cases there was a significant decrease in the conversion of aflatoxin B1 to aflatoxin Q1 (compared with that of controls treated with corn oil).
Interaction of acetogens and methanogens in anaerobic freshwater sediments
Authors: Jones J G , Simon B M
Published: January 2020

Anaerobic decomposition processes in the profundal sediments of Blelham Tarn (English Lake District) are often limited during late summer by the input of organic carbon. The concentration of acetate in the interstitial water fell from about 100 microM (immediately after sedimentation of the spring diatom bloom) to a relatively constant value of about 20 microM in late summer, during which acetate utilization appeared to be balanced by production. Addition of chloroform and molybdate caused an accumulation of cold acetate in large sediment cores and of [14C]acetate in small cores to which [14C]bicarbonate had been added. In both cases chloroform caused the greater accumulation, implying that acetoclastic methanogens were the more active consumers. The conversion of 14CO2 to [14C]acetate was inversely related, with depth, to its conversion to 14CH4. Methanogenesis from CO2 decreased during late summer, whereas acetogenesis and acetoclastic methanogenesis increased over the same time period. The production of acetate from CO2 was generally equivalent to less than 10% of the acetate carbon utilized but could be as high as 25% of that value. Hydrogen consumption by acetogens could be as high as 50% of that utilized in methanogenesis. The role of acetogenic bacteria in anaerobic processes may therefore be of greater significance in lakes such as Blelham Tarn than in more eutrophic systems.
12 beta-dehydrogenation of bile acids by Clostridium paraputrificum, C. tertium, and C. difficile and epimerization at carbon-12 of deoxycholic acid by cocultivation with 12 alpha-dehydrogenating Eubacterium lentum
Authors: Edenharder R , Schneider J
Published: January 2020

12 beta-Hydroxysteroid dehydrogenating activities were detected in 13 strains of Clostridium paraputrificum, 1 strain of C. tertium, and 1 strain of C. difficile, together with a 3 alpha- and 3 beta-hydroxysteroid dehydrogenase system in many strains. Redox reactions a C-12 of disubstituted and trisubstituted bile acids were performed unspecifically by representative strains of C. paraputrificum. 3 alpha,12 beta-, 3 beta,12 beta-Dihydroxy-, 3 alpha, 7 alpha, 12 beta-trihydroxy-, and 3-keto,12 beta-hydroxy-5 beta-cholanoic acids, so far not known as bacterial bile acid metabolites, were identified. Epimerization of the 12 alpha-hydroxyl group of deoxycholate via the 12-keto intermediate was achieved by cocultivation of C. paraputrificum and Eubacterium lentum, elaborating a 12 alpha-hydroxysteroid dehydrogenase only. In addition, epimerization at C-12 was demonstrated with mixed human fecal cultures.
Photoreactivation of UV-irradiated Legionella pneumophila and other Legionella species
Authors: Knudson G B
Published: January 2020

Shortwave UV light was assessed as a feasible modality for the control of Legionnaires disease bacterium in water. The results of this study show that Legionella pneumophila and six other Legionella species are very sensitive to low doses of UV. However, all Legionella species tested effectively countered the germicidal effect of UV when subsequently exposed to photoreactiving light.
Use of the Mushroom Tissue Block Rapid Pitting Test to Detect Brown Blotch Pathogens
Authors: Bessette Alan E.
Published: January 2020

Isolates of an
Arthrobacter
species known to produce a positive host pathogenicity test were evaluated by the mushroom tissue block rapid pitting test. All 11 isolates of the
Arthrobacter
species yielded a positive test response. The time required for a positive test was the same for
Pseudomonas tolaasi
and the
Arthrobacter
species.
Adaptation of Denitrifying Populations to Low Soil pH
Authors: Parkin Timothy B. , Sexstone Alan J. , Tiedje James M.
Published: January 2020

Natural denitrification rates and activities of denitrifying enzymes were measured in an agricultural soil which had a 20-year past history of low pH (pH ca. 4) due to fertilization with acid-generating ammonium salts. The soil adjacent to this site had been limed and had a pH of ca. 6.0. Natural denitrification rates of these areas were of similar magnitude: 158 ng of N g
−1
of soil day
−1
for the acid soil and 390 ng of N g
−1
of soil day
−1
at the neutral site. Estimates of in situ denitrifying enzyme activity were higher in the neutral soil, but substantial enzyme activity was also detected in the acid soil. Rates of nitrous oxide reduction were very low, even when NO
3
−
and NO
2
−
were undetectable, and were ca. 400 times lower than the rates of N
2
O production from NO
3
−
. Denitrification rates measured in slurries of the acid and neutral soil showed distinctly different pH optima (pH 3.9 and pH 6.3) which were near the pH values of the two soils. This suggests that an acid-tolerant denitrifying population had been selected during the 20-year period of low pH.
Biological and Abiological Sulfur Reduction at High Temperatures
Authors: Belkin Shimshon , Wirsen Carl O. , Jannasch Holger W.
Published: January 2020

Reduction of elemental sulfur was studied in the presence and absencè of thermophilic sulfur-reducing bacteria, at temperatures ranging from 65 to 110°C, in anoxic artificial seawater media. Above 80°C, significant amounts of sulfide were produced abiologically at linear rates, presumably by the disproportionation of sulfur. These rates increased with increasing temperature and pH and were enhanced by yeast extract. In the same medium, the sulfur respiration of two recent thermophilic isolates, a eubacterium and an archaebacterium, resulted in sulfide production at exponential rates. Although not essential for growth, sulfur increased the cell yield in both strains up to fourfold. It is suggested that sulfur respiration is favored at high temperatures and that this process is not limited to archaebacteria, but is shared by other extreme thermophiles.
A stable plasmid vector and control of its copy number in Bacillus brevis 47, a protein-producing bacterium
Authors: Yamagata H , Nakagawa K , Tsukagoshi N , Udaka S
Published: January 2020

A low-copy-number plasmid vector, pHY481, was constructed by combining a macrolide resistance gene of a Staphylococcus aureus plasmid with a cryptic plasmid found in a Bacillus brevis strain isolated from soil. The plasmid introduced into B. brevis 47, an extensively investigated protein-producing bacterium, was maintained very stably in the absence of selective antibiotics. A Bacillus megaterium alpha-amylase gene subcloned into pHY481 was retained much more stably in B. brevis 47 than one subcloned into a plasmid of S. aureus origin. B. brevis 47 mutants were also isolated in which the copy number of pHY481 was amplified about 10-fold. The copy number of pHY481 with the inserted amylase gene also increased in the mutants. As a result, a severalfold-higher amount of the enzyme was produced in the mutants compared with that produced in wild-type B. brevis 47. Thus, the plasmid vector constructed here and the copy-number mutants of B. brevis 47 are useful for cloning foreign genes and performing genetic engineering in the protein-producing bacterium.
Inhibitory Effect of Pseudobactin on the Uptake of Iron by Higher Plants
Authors: Becker J. O. , Hedges R. W. , Messens E.
Published: January 2020

Purified pseudobactin inhibits the uptake of ferric iron by the roots of peas and maize plants sufficiently to reduce the synthesis of chlorophyll. This inhibition is interpreted as competitive binding, as described for synthetic chelating compounds.
Metabolism of ochratoxin B and its possible effects upon the metabolism and toxicity of ochratoxin A in rats
Authors: Størmer F C , Kolsaker P , Holm H , Rogstad S , Elling F
Published: January 2020

A metabolic product was formed from ochratoxin B by rat liver microsomal fractions in the presence of NADPH. It was isolated from the incubation mixture by extraction, thin-layer chromatography, high-pressure liquid chromatography, and crystallization. On the basis of mass and nuclear magnetic resonance spectroscopy, the structure is suggested to be 4-hydroxyochratoxin B. The Km for the formation of 4-hydroxyochratoxin B was determined, and the hydroxylation of ochratoxin A was not altered by the presence of ochratoxin B. Rats were given ochratoxin A or B, or a mixture of both intraperitoneally. The ratios of the three metabolites, ochratoxin A, (4R)-4-hydroxyochratoxin A, and ochratoxin alpha, excreted in the urine did not change in the presence of ochratoxin B. Ochratoxin B was metabolized to 4-hydroxyochratoxin B and ochratoxin beta, but in a different ratio than for the ochratoxin A metabolites. When given intraperitoneally, ochratoxin beta was excreted within 24 h. In rats treated with ochratoxin A alone, the food intake was reduced by 50%, and histologically severe lesions, degeneration, and necrosis were observed in the proximal tubules. When ochratoxin A and B given in combination, the animals were clinically unaffected and histologically there was only slight damage of proximal tubules. These observations indicate that ochratoxin B considerably reduces the toxic effects of ochratoxin A.
15
N Kinetic Analysis of N
2
O Production by
Nitrosomonas europaea
: an Examination of Nitrifier Denitrification
Authors: Poth Mark , Focht Dennis D.
Published: January 2020

A series of
15
N isotope tracer experiments showed that
Nitrosomonas europaea
produces nitrous oxide only under oxygen-limiting conditions and that the labeled N from nitrite, but not nitrate, is incorporated into nitrous oxide, indicating the presence of the “denitrifying enzyme” nitrite reductase. A kinetic analysis of the
m/z
44, 45, and 46 nitrous oxide produced by washed cell suspensions of
N. europaea
when incubated with 4 mM ammonium (99%
14
N) and 0.4 mM nitrite (99%
15
N) was performed. No labeled nitrite was reduced to ammonium. All labeled material added was accounted for as either nitrite or nitrous oxide. The hypothesis that nitrous oxide is produced directly from nitrification was rejected since (i) it does not allow for the large amounts of double-labeled (
m/z
46) nitrous oxide observed; (ii) the observed patterns of
m/z
44, 45, and 46 nitrous oxide were completely consistent with a kinetic analysis based on denitrification as the sole mechanism of nitrous oxide production but not with a kinetic analysis based on both mechanisms; (iii) the asymptotic ratio of
m/z
45 to
m/z
46 nitrous oxide was consistent with denitrification kinetics but inconsistent with nitrification kinetics, which predicted no limit to
m/z
45 production. It is concluded that
N. europaea
is a denitrifier which, under conditions of oxygen stress, uses nitrite as a terminal electron acceptor and produces nitrous oxide.
Stimulation of 16-dehydroprogesterone and progesterone reductases of Eubacterium sp. strain 144 by hemin and hydrogen or pyruvate
Authors: Glass T L , Burley C Z
Published: January 2020

Suspensions of Eubacterium sp. strain 144, prepared from cells grown with 16-dehydroprogesterone, catalyzed the reduction of this steroid to 17-isoprogesterone at a very low rate. Modifications of the assay to optimize the pH (5.5) and increase the steroid solubility (10% [vol/vol] methanol) did not significantly enhance the reaction. However, growth of strain 144 in the presence of hemin was found to stimulate 16-dehydroprogesterone reductase during the initial 30 min of incubation, giving a biphasic time course. These biphasic kinetics could be eliminated by providing the cells with an exogenous electron donor. Strain 144 used either H2 or pyruvate for this purpose, and 17-isoprogesterone formation was nearly complete after 20 to 30 min of incubation. However, under these conditions, strain 144 further converted 17-isoprogesterone to products which lacked UV absorbance (254 nm). When progesterone was used as a substrate, it was found that strain 144 could reduce the C4-C5 double bond of this steroid by a progesterone reductase to give mostly 5 beta-pregnadione and some 5 alpha-pregnadione. Furthermore, the 3-keto group of 5 beta-pregnadione steroid was also reduced to a hydroxy function. The maximum activities of both 16-dehydroprogesterone and progesterone reductases in cell suspensions required the growth of strain 144 with hemin and 16-dehydroprogesterone and the presence of H2 or pyruvate.
Characterization and molecular cloning of cryptic plasmids isolated from Lactobacillus casei
Authors: Lee-Wickner L J , Chassy B M
Published: January 2020

Four small cryptic plasmids were isolated from Lactobacillus casei strains, and restriction endonuclease maps of these plasmids were constructed. Three of the small plasmids (pLZ18C, pLZ19E, and pLZ19F1; 6.4, 4.9, and 4.8 kilobase pairs, respectively) were cloned into Escherichia coli K-12 by using pBR322, pACYC184, and pUC8 as vectors. Two of the plasmids, pLZ18C and pLZ19E, were also cloned into Streptococcus sanguis by using pVA1 as the vector. Hybridization by using nick-translated cloned 32P-labeled L. casei plasmid DNA as the probe revealed that none of the cryptic plasmids had appreciable DNA-DNA homology with the large lactose plasmids found in the L. casei strains, with chromosomal DNAs isolated from these strains. Partial homology was detected among several plasmids isolated from different strains, but not among cryptic plasmids isolated from the same strain.
General Biochemical Characterization of Thermostable Extracellular β-Amylase from
Clostridium thermosulfurogenes
Authors: Hyun H. H. , Zeikus J. G.
Published: January 2020

Clostridium thermosulfurogenes
, an anaerobic bacterium which ferments starch into ethanol at 62°C, produced an active extracellular amylase and contained intracellular glucoamylase but not pullulanase activity. The extracellular amylase was purified 2.4-fold, and its general physicochemical and catalytic properties were examined. The extracellular amylase was characterized as a β-amylase (1,4-α-
d
-glucan maltohydrolase) based on demonstration of exocleavage activity and the production of maltose with a β-anomeric configuration from starch. The β-amylase activity was stable and optimally active at 80 and 75°C, respectively. The pH optimum for activity and the pH stability range was 5.5 to 6 and 3.5 to 6.5, respectively. The apparent [S]

0.5
V

and
V
max
for β-amylase activity on starch was 1 mg/ml and 60 U/mg of protein. Similar to described β-amylase, the enzyme was inhibited by
p
-chloromercuribenzoate, Cu
2+
, and Hg
2+
; however, α- and β-cyclodextrins were not competitive inhibitors. The β-amylase was active and stable in the presence of air or 10% (vol/vol) ethanol. The β-amylase and glucoamylase activities enabled the organism to actively ferment raw starch in the absence of significant pullulanase or α-amylase activity.
Effect of temperature, pH, and oxygen level on the multiplication of naturally occurring Legionella pneumophila in potable water
Authors: Wadowsky R M , Wolford R , McNamara A M , Yee R B
Published: January 2020

A water culture containing naturally occurring Legionella pneumophila and associated microbiota was maintained in the laboratory by serially transferring the culture in tap water which had been sterilized by membrane filtration. Successful maintenance of the water culture depended upon transferring the culture when the growth of L. pneumophila was in the late-exponential to early-stationary phase. The water culture was used as a source of naturally occurring bacteria to determine some of the parameters which affect the multiplication of L. pneumophila in tap water. Naturally occurring L. pneumophila multiplied at a temperature between 25 and 37 degrees C, at pH levels of 5.5 to 9.2, and at concentrations of dissolved oxygen of 6.0 to 6.7 mg/liter. Multiplication did not occur in tap water which contained less than 2.2 mg of dissolved oxygen per liter. An association was observed between the multiplication of L. pneumophila and the non-Legionellaceae bacteria which were also present in the water culture. The method of preserving naturally occurring L. pneumophila and associated microbiota may facilitate studies on the symbiosis of L. pneumophila with other microorganisms.
Effect of non-Legionellaceae bacteria on the multiplication of Legionella pneumophila in potable water
Authors: Wadowsky R M , Yee R B
Published: January 2020

A naturally occurring suspension of Legionella pneumophila and associated microbiota contained three unidentified non-Legionellaceae bacteria which supported satellite growth of a subculture of L. pneumophila on an L-cysteine-deficient medium and another bacterium which did not support growth of the subculture. Washed suspensions containing 10(3), 10(5), 10(7), or 10(8) CFU of a mixture of isolates of these non-Legionellaceae bacteria failed to support the multiplication of an isolate of agar-grown L. pneumophila which had been washed and seeded into the suspensions. The suspensions which contained 10(3), 10(5), or 10(7) CFU of the non-Legionellaceae bacteria per ml appeared to enhance survival or cryptic growth of agar-grown L. pneumophila. A decline of 1.3 log CFU of L. pneumophila per ml occurred within the first week of incubation in the sample which contained 10(8) CFU of the non-Legionellaceae bacteria per ml. In contrast to these results, naturally occurring L. pneumophila multiplied in the presence of associated microbiota. The necessity to subculture L. pneumophila and the non-Legionellaceae bacteria on artificial medium to obtain pure cultures may have affected the multiplication of L. pneumophila in tap water. Alternatively, other microorganisms may be present in the naturally occurring suspension which support the growth of this bacterium.
Properties of lactate dehydrogenase in a psychrophilic marine bacterium
Authors: Mitchell P , Yen H C , Mathemeier P F
Published: January 2020

Lactate dehydrogenase (EC 1.1.1.27) from Vibrio marinus MP-1 was purified 15-fold and ammonium activated. The optimum pH for pyruvate reduction was 7.4. Maximum lactate dehydrogenase activity occurred at 10 to 15 degrees C, and none occurred at 40 degrees C. The crude-extract enzyme was stable between 15 and 20 degrees C and lost 50% of its activity after 60 min at 45 degrees C. The partially purified enzyme was stable between 8 and 15 degrees C and lost 50% of its activity after 60 min at 30 degrees C. The thermal stability of lactate dehydrogenase was increased by mercaptoethanol, with 50% remaining activity at 42 degrees C.
An instrument for the immediate quantification of bacteria in potable waters
Authors: Wallis C , Melnick J L
Published: January 2020

A new semiautomated instrument is described which quantifies the number of bacteria in potable waters within 3 min, providing a permanent colorimetric record of the results. The bacteria detection device can measure as few as 100 CFU/ml in potable waters. In brief, a 100- to 1,000-ml sample of tap water is drawn through a large surface, customized filter housed in the device, and bacteria, rust, and humic acid in the water are concentrated thereon. A reducing agent is used to remove the rust and humic acid from the filter. The filter is inverted and backflushed to elute the bacteria which are collected and reconcentrated onto a 7-mm-diameter filter surface. The reconcentrated bacteria are stained, and the filter fibers are preferentially decolorized without removing the dye from the bacteria. The color intensity of the filter surface is compared with a color guide to determine the amount of bacteria in the test water.
Effects of humic materials on virus recovery from water
Authors: Guttman-Bass N , Catalano-Sherman J
Published: January 2020

Humic and fulvic acids were tested for their ability to interfere with virus recovery by microporous filters. Two electropositively charged types of filter (Seitz S and Zeta Plus 60S) were used to concentrate poliovirus in the presence of humic materials. Humic acid inhibited virus adsorption, but even at the highest humic acid concentrations tested (200 mg/liter), 30 to 40% of the virus was recovered by the filters. Fulvic acid, tested with Zeta Plus filters, did not affect virus recovery. For comparison, two electronegatively charged filter types were tested (Cox and Balston). These two types of filter were more sensitive to interference at lower concentrations of humic acid than the more positively charged filters. With Balston filters, at humic acid concentrations above 10 mg/liter, most of the virus was recovered in the filtrate. Fulvic acid, tested with Balston filters, did not interfere with virus recovery. With the electropositively charged filters, the humic materials adsorbed efficiently, even at high input concentrations. Interference with virus adsorption occurred at humic acid concentrations which were below the level of saturation of the filters. In addition, in high-volume experiments, humic acid led to premature blockage of the filters. The efficiency of virus recovery by a second concentration step, organic flocculation of the filter eluate, was tested. For all the filter types tested, this procedure was not affected by the presence of humic or fulvic acid in the input water.
Production and regulation of cellulase by two strains of the rumen anaerobic fungus Neocallimastix frontalis
Authors: Mountfort D O , Asher R A
Published: January 2020

Cellulase production was examined in two strains of Neocallimastix frontalis, namely, PN-1 isolated from the ovine rumen, and PN-2 from the bovine rumen. For both strains, carboxymethylcellulase (CMCase) had a pH optimum of 6.0 and a temperature optimum of 50 degrees C. CMCase resided mainly in the culture fluid, and activities up to 170 U ml-1 (1 U represents 1 microgram of glucose equivalents released per min) were obtained for cultures grown on 2.5 mg of cellulose ml-1. For resting cultures of strain PN-1, the yield of CMCase increased from 9.9 X 10(3) to 10.4 X 10(4) U per g of cellulose degraded, as the initial cellulose concentration decreased from 10 to 0.58 mg ml-1. The range for PN-2 was 8.1 X 10(3) to 11 X 10(4) U g-1. Shaking cultures improved yields for strain PN-1 but not for PN-2. Decreased CMCase production at high initial cellulose concentrations concurred with accumulation of glucose, and addition of glucose (4 mg ml-1) to cultures grown on low cellulose in which none of the sugar accumulated repressed CMCase. Adsorption of CMCase was excluded as a likely explanation for decreased yields at high initial cellulose as only a low proportion (less than 20%) of the enzyme was adsorbed onto the growth substrate. Exoglucanase, measured with alkali-treated Sigmacell or Avicel, gave low levels of activity in the culture fluid (less than 2 U ml-1) and did not appear to be associated with the fungal rhizoid, as treatment with various solubilizing agents failed to give increased activity.(ABSTRACT TRUNCATED AT 250 WORDS)
Effects of Environmental Factors on Toxicity of a Cyanobacterium (
Microcystis aeruginosa
) under Culture Conditions
Authors: Watanabe Mariyo F. , Oishi Shinshi
Published: January 2020

Effects of light intensity, temperature, and nutrients on the toxicity of
Microcystis aeruginosa
were investigated, using a toxic strain which kills mice. A marked change in toxicity was observed in the light intensity experiment, and slight changes were observed to be caused by temperature and phosphorus deficiency.
A Gram-Negative Anaerobic Bacterium That Utilizes
O
-Methyl Substituents of Aromatic Acids
Authors: Frazer Anne Cornish , Young L. Y.
Published: January 2020

A novel strain of gram-negative anaerobic rods which utilized
O
-methyl substituents of monoaromatic acids as a sole organic source of carbon was isolated from municipal sewage sludge. Energy for growth seemed to be generated by an acetate formation pathway. The growth yield in defined medium was 7.9 g (dry weight) of cells per mol of ferulate utilized. This isolate and other
O
-demethylating anaerobes may play a role in the turnover of acetate and the metabolism of highly methoxylated lignaceous materials in anaerobic environments.
Study of
Bacillus subtilis
Endospores in Soil by Use of a Modified Endospore Stain
Authors: Mormak David A. , Casida L. E.
Published: January 2020

The Schaeffer-Fulton endospore stain was modified so that it would stain
Bacillus subtilis
endospores in soil smears. The modified stain differentiated among dormant spores, spores undergoing activation, and spores which had germinated but had not yet shown outgrowth. These differentiations were seen for spores in soil and for pure spore preparations in the laboratory. This stain was used to show reversible
B. subtilis
spore activation promoted by an
Ensifer adhaerens
-like indigenous bacterium in soil and by pure cultures of
E. adhaerens
added to spores in the laboratory. Under the specific conditions in the laboratory, spore germination did not proceed beyond the activation stage, and relatively little change occurred in the numbers of both
E. adhaerens
and
B. subtilis.
This was also true in soil, although some germination with destruction of spores and vegetative cells did occur if the soil had been nutritionally enriched by preincubation with incorporated ground alfalfa.
UV inactivation of pathogenic and indicator microorganisms
Authors: Chang J C , Ossoff S F , Lobe D C , Dorfman M H , Dumais C M , Qualls R G , Johnson J D
Published: January 2020

Survival was measured as a function of the dose of germicidal UV light for the bacteria Escherichia coli, Salmonella typhi, Shigella sonnei, Streptococcus faecalis, Staphylococcus aureus, and Bacillus subtilis spores, the enteric viruses poliovirus type 1 and simian rotavirus SA11, the cysts of the protozoan Acanthamoeba castellanii, as well as for total coliforms and standard plate count microorganisms from secondary effluent. The doses of UV light necessary for a 99.9% inactivation of the cultured vegetative bacteria, total coliforms, and standard plate count microorganisms were comparable. However, the viruses, the bacterial spores, and the amoebic cysts required about 3 to 4 times, 9 times, and 15 times, respectively, the dose required for E. coli. These ratios covered a narrower relative dose range than that previously reported for chlorine disinfection of E. coli, viruses, spores, and cysts.