bluuebunny/crossref_metadata_2025 huggingface dataset:
Sustained Photoproduction of Ammonia from Nitrate by
Anacystis nidulans
Authors: Ramos Juan L. , Guerrero Miguel G. , Losada Manuel
Published: January 2020

Conditions that lengthen the time during which
l
-methionine-
dl
-sulfoximine (MSX) promotes excretion of ammonia produced by photosynthetic nitrate reduction in
Anacystis nidulans
have been sought. If MSX was added every 24 h, maximal rates of ammonia production were maintained for 3 days. After this time, ammonia production ceased due to a specific deficiency of glutamine in the cells, which finally led to cell lysis. The effective ammonia production period could be further extended either by adding a low amount of glutamine at the end of the 3-day period or by allowing the cells to recover for 8 h in the absence of MSX after every 48-h period in the presence of inhibitor. In this way, a steady production of ammonia lasting for at least 10 days was achieved. The MSX-treated cyanobacterial cells thus represent a system relatively stable with time for the conversion of light energy into chemical energy through the photoreduction of nitrate to ammonia.
Specificity of bile salt sulfatase activity from Clostridium sp. strains S1
Authors: Huijghebaert S M , Eyssen H J
Published: January 2020

Clostridium sp. strain S1, an unnamed bile acid-desulfating strain from rat intestinal microflora (S.M. Huijghebaert, J. A. Mertens, and H. J. Eyssen, Appl. Environ. Microbiol. 43:185-192, 1982), was examined for its ability to desulfate different bile acid sulfates and steroid sulfates in growing cultures. Clostridium sp. strain S1 desulfated the 3 alpha-monosulfates of chenodeoxycholic, deoxycholic, and cholic acid, but not their 7 alpha- or 12 alpha-monosulfates. Among the 3-sulfates of the 5 alpha- and 5 beta-bile acids, only bile acid-3-sulfates with an equatorial sulfate group were desulfated. Hence, Clostridium sp. strain S1 desulfated the 3-sulfates of bile acids with a 3 alpha, 5 beta-, a 3 beta, 5 alpha- or a 3 beta, delta 5-structure. In contrast, the bile acid-3-sulfates with a 3 beta, 5 beta- or a 3 alpha, 5 alpha-structure were not desulfated. In addition, Clostridium sp. strain S1 did not hydrolyze the equatorial 3-sulfate esters of C19 and C21 steroids and cholesterol or the phenolic 3-sulfate esters of estrone and estradiol. 23-Nordeoxycholic acid with a C-23 carboxyl group was also not desulfated, in contrast to the 5 beta-bile acid 3 alpha-sulfates with a C-24 or C-26 carboxyl group. Therefore, the specificity of the sulfatase of Clostridium sp. strain S1 is related to the location of the sulfate group on the bile acid molecule, the equatorial orientation of the sulfate group, and the structure of the C-17 side chain, its carboxyl group, and chain length.
Direct Fermentation of
d
-Xylose to Ethanol by
Kluyveromyces marxianus
Strains
Authors: Margaritis Argyrios , Bajpai Pratima
Published: January 2020

Eight strains of
Kluyveromyces marxianus
were screened, and all of them were found to ferment the aldopentose
d
-xylose directly to ethanol under aerobic conditions. One of these strains,
K. marxianus
SUB-80-S, was grown in a medium containing 20 g of
d
-xylose per liter, and the following results were obtained: maximum ethanol concentration, 5.6 g/liter; ethanol yield, 0.28 g of ethanol per g of
d
-xylose (55% of theoretical); maximum specific growth rate, 0.12 h
−1
; 100%
d
-xylose utilization was completed in 48 h.
Plants as Sources of Airborne Bacteria, Including Ice Nucleation-Active Bacteria
Authors: Lindemann Julianne , Constantinidou Helen A. , Barchet William R. , Upper Christen D.
Published: January 2020

Vertical wind shear and concentration gradients of viable, airborne bacteria were used to calculate the upward flux of viable cells above bare soil and canopies of several crops. Concentrations at soil or canopy height varied from 46 colony-forming units per m
3
over young corn and wet soil to 663 colony-forming units per m
3
over dry soil and 6,500 colony-forming units per m
3
over a closed wheat canopy. In simultaneous samples, concentrations of viable bacteria in the air 10 m inside an alfalfa field were fourfold higher than those over a field with dry, bare soil immediately upwind. The upward flux of viable bacteria over alfalfa was three- to fourfold greater than over dry soil. Concentrations of ice nucleation-active bacteria were higher over plants than over soil. Thus, plant canopies may constitute a major source of bacteria, including ice nucleation-active bacteria, in the air.
Mechanisms of inactivation of poliovirus by chlorine dioxide and iodine
Authors: Alvarez M E , O'Brien R T
Published: January 2020

Chlorine dioxide and iodine inactivated poliovirus more efficiently at pH 10.0 than at pH 6.0. Sedimentation analyses of viruses inactivated by chlorine dioxide and iodine at pH 10.9 showed that viral RNA separated from the capsids, resulting in the conversion of virions from 156S structures to 80S particles. The RNAs release from both chlorine dioxide- and iodine-inactivated viruses cosedimented with intact 35S viral RNA. Both chlorine dioxide and iodine reacted with the capsid proteins of poliovirus and changed the pI from pH 7.0 to pH 5.8. However, the mechanisms of inactivation of poliovirus by chlorine dioxide and iodine were found to differ. Iodine inactivated viruses by impairing their ability to adsorb to HeLa cells, whereas chlorine dioxide-inactivated viruses showed a reduced incorporation of [14C]uridine into new viral RNA. We concluded, then, that chlorine dioxide inactivated poliovirus by reacting with the viral RNA and impairing the ability of the viral genome to act as a template for RNA synthesis.
Bacterial bioluminescence as a bioassay for mycotoxins
Authors: Yates I E , Porter J K
Published: January 2020

The use of bacterial bioluminescence as a toxicological assay for mycotoxins was tested with rubratoxin B, zearalenone, penicillic acid, citrinin, ochratoxin A, PR-toxin, aflatoxin B1, and patulin. The concentrations of mycotoxins causing 50% light reduction (EC50) in Photobacterium phosphoreum were determined immediately and at 5 h after reconstitution of the bacteria from a freeze-dried state. Generally, less toxins were required to obtain an EC50 at 5 h. The effects of the above mycotoxins on bioluminescence were determined after 5, 10, 15, and 20 min of incubation with the bacterial suspensions. The concentration of rubratoxin B necessary to elicit an EC50 increased with time, whereas the concentration of citrinin, penicillic acid, patulin, and PR-toxin necessary decreased with time. There was very little change in the concentration of zearalenone, aflatoxin B1, and ochratoxin A required to elicit an EC50 with time. The bacterial bioluminescence assay was most sensitive to patulin and least sensitive to rubratoxin B.
Reactivity of aflatoxin B2a antibody with aflatoxin B1-modified DNA and related metabolites
Authors: Pestka J J , Li Y K , Chu F S
Published: January 2020

Aflatoxin B2a (AFB2a) antiserum has been previously used in an enzyme-linked immunosorbent assay (ELISA) for the quantitation of AFB1 and AFB2a. The present investigation examined the reactivity of the antiserum toward those adducts and metabolites of AFB1 believed to play a major role in aflatoxicosis and carcinogenesis. 2,3-Dihydro-2-(N7-guanyl)-3-hydroxyaflatoxin B1 (AFB1-N7-Gua), the putative 2,3-(N5-formyl-2-2', 5',6'-triamino-4-oxo-N5-pyrimidyl)-3-hydroxyaflatoxin B1 (AFB1-FAPyr), 2,3-dihydro-2,3-dihydroxyaflatoxin B1 (AFB1-diol), AFB1-N7-Gua-modified DNA, and AFB1-FAPyr-modified DNA were prepared by in vitro incubation or chemical methods and subjected to competitive AFB2a ELISA. The antiserum showed significant reactivity with all five compounds, indicating that it had a high degree of specificity for both the cyclopentenone and the methoxy group of the parent aflatoxin molecule. Sensitivity for AFB-N7-Gua-modified DNA, AFB1-FAPyr-modified DNA, and AFB1-diol by the ELISA method was 0.1 pmol per assay. To test the applicability of immunological detection of covalent binding of AFB1 to DNA, the ELISA was compared with a conventional radioisotopic assay in two in vitro studies. The results showed that estimates of the kinetics and substrate dependence of covalent binding to calf thymus DNA in rat microsomal incubation mixtures by both methods were comparable. The broad specificity AFB2a antibody might be of considerable value in the detection of AFB1 macromolecular adducts and related metabolites in epidemiological investigations or in the diagnosis of aflatoxicosis.
Optimal Cultural and Physiological Conditions for Handling
Streptomyces rimosus
Protoplasts
Authors: Pigac Jasenka , Hranueli Daslav , Smokvina Tamara , Alačević Marija
Published: January 2020

A general procedure for manipulating protoplasts of three
Streptomyces rimosus
strains was developed. More than 50% regeneration efficiency was obtained by optimizing the osmotic stabilizer concentrations and modifying the plating procedure. Preparation and regeneration of protoplasts were studied by both phase-contrast and electron microscopy. After cell wall degradation with lysozyme, protoplasts about 1,000 to 1,500 nm in diameter appeared. The reversion process exhibited normal and aberrant regeneration of protoplasts to hyphae and to spherical cells, respectively. Spherical cells contained no α, ε-
ll
-diaminopimelic acid and were colorless or red after Gram staining. They showed consistent stability during at least five subsequent subcultivations. However, the omission of glycine from the precultivation medium reduced the unusual process of regeneration almost completely. After normal protoplast regeneration, the production of oxytetracycline by single isolates was not affected.
Factors Regulating Microbial Biofilm Development in a System with Slowly Flowing Seawater
Authors: Pedersen Karsten
Published: January 2020

Microbial biofilm development was followed under growth conditions similar to those of a projected salinity power plant. Microscope glass cover slips were piled in biofilm reactors to imitate the membrane stacks in such a plant. A staining technique closely correlating absorbance values with biofilm dry weight was used for the study. Generally, the biofilms consisted of solitary and filamentous bacteria which were evenly distributed with considerable amounts of various protozoa and entrapped debris of organic origin. Protozoa predation was shown to decrease the amount of biofilm produced. The biofilm development lag phase was longer at lower temperatures. The subsequent growth phase was approximately arithmetic until stationary phase appeared. Adaptation of a hyperbolic saturation function gave curves that agreed well with the logarithm of the amount of biofilm as a function of time. Increased flow velocity, temperature, and nutrient concentration increased the biofilm production rate. An exponential relationship was shown between biofilm production rate and flow velocity within the range of 0 to 15 cm s
−1
. Intervals in which the biofilms were exposed to fresh water decreased the biofilm production rate more than four times. If the cover slips were inoculated with untreated seawater for 24 h, subsequent UV treatment had an insignificant effect on the biofilm formation.
Methanogenesis and Sulfate Reduction: Competitive and Noncompetitive Substrates in Estuarine Sediments
Authors: Oremland Ronald S. , Polcin Sandra
Published: January 2020

Sulfate ions did not inhibit methanogenesis in estuarine sediments supplemented with methanol, trimethylamine, or methionine. However, sulfate greatly retarded methanogenesis when hydrogen or acetate was the substrate. Sulfate reduction was stimulated by acetate, hydrogen, and acetate plus hydrogen, but not by methanol or trimethylamine. These results indicate that sulfate-reducing bacteria will outcompete methanogens for hydrogen, acetate, or both, but will not compete with methanogens for compounds like methanol, trimethylamine, or methionine, thereby allowing methanogenesis and sulfate reduction to operate simultaneously within anoxic, sulfate-containing sediments.
Estimates of bacterial growth from changes in uptake rates and biomass
Authors: Kirchman D , Ducklow H , Mitchell R
Published: January 2020

Rates of nucleic acid synthesis have been used to examine microbiol growth in natural waters. These rates are calculated from the incorporation of [3H]adenine and [3H]thymidine for RNA and DNA syntheses, respectively. Several additional biochemical parameters must be measured or taken from the literature to estimate growth rates from the incorporation of the tritiated compounds. We propose a simple method of estimating a conversion factor which obviates measuring these biochemical parameters. The change in bacterial abundance and incorporation rates of [3H]thymidine was measured in samples from three environments. The incorporation of exogenous [3H]thymidine was closely coupled with growth and cell division as estimated from the increase in bacterial biomass. Analysis of the changes in incorporation rates and initial bacterial abundance yielded a conversion factor for calculating bacterial production rates from incorporation rates. Furthermore, the growth rate of only those bacteria incorporating the compound can be estimated. The data analysis and experimental design can be used to estimate the proportion of nondividing cells and to examine changes in cell volumes.
Acetone and Butanol Production by
Clostridium acetobutylicum
in a Synthetic Medium
Authors: Monot Frédéric , Martin Jean-René , Petitdemange Henri , Gay Robert
Published: January 2020

The effect of the component concentrations of a synthetic medium on acetone and butanol fermentation by
Clostridium acetobutylicum
ATCC 824 was investigated. Cell growth was dependent on the presence of Mg, Fe, and K in the medium. Mg and Mn had deleterious effects when in excess. Ammonium acetate in excess caused acid fermentation. The metabolism was composed of two phases: an acid phase and a solvent one. Low concentrations of glucose allowed the first phase only. The theoretical ratio of the conversion of glucose to solvents, which was 28 to 33%, was obtained with the following medium: MgSO
4
, 50 to 200 mg/liter; MnSO
4
, 0 to 20 mg/liter; KCl, 0.015 to 8 g/liter (an equivalent concentration of K
+
was supplied in the form of KH
2
PO
4
and K
2
HPO
4
); FeSO
4
, 1 to 50 mg/liter; ammonium acetate, 1.1 to 2.2 g/liter;
para
-aminobenzoic acid, 1 mg/liter; biotin, 0.01 mg/liter; glucose, 20 to 60 g/liter.
Ethanol Inhibition Kinetics of
Kluyveromyces marxianus
Grown on Jerusalem Artichoke Juice
Authors: Bajpai Pratima , Margaritis Argyrios
Published: January 2020

The kinetics of ethanol inhibition on cell growth and ethanol production by
Kluyveromyces marxianus
UCD (FST) 55-82 were studied during batch growth. The liquid medium contained 10% (wt/vol) inulin-type sugars derived from an extract of Jerusalem artichoke (
Helianthus tuberosus
) tubers, supplemented with small amounts of Tween 80, oleic acid, and corn steep liquor. Initial ethanol concentrations ranging from 0 to 80 g/liter in the liquid medium were used to study the inhibitory effect of ethanol on the following parameters: maximum specific growth rate (μ
max
), cell and ethanol yields, and sugar utilization. It was found that as the initial ethanol concentration increased from 0 to 80 g/liter, and maximum specific growth rate of
K. marxianus
cells decreased from 0.42 to 0.09 h
−1
, whereas the ethanol and cell yields and sugar utilization remained almost constant. A simple kinetic model was used to correlate the μ
max
results and the rates of cell and ethanol production, and the appropriate constants were evaluated.
Viricidal Capability of Resin-Triiodide Demand-Type Disinfectant
Authors: Fina Louis R. , Hassouna Nadia , Horacek Gary L. , Lambert John P. , Lambert Jack L.
Published: January 2020

Polyoma, Newcastle disease virus, and adenovirus, as well as two coliphages, lambda and T4, were inactivated by strong base quaternary ammonium anion-exchange resin-triiodide. Organic matter interfered with viral inactivation capability of the resin-triiodide. The viruses, as they were being inactivated by the resin disinfectant beads, were not retained or filtered by the beads.
Kinetics of Hydrogen Consumption by Rumen Fluid, Anaerobic Digestor Sludge, and Sediment
Authors: Robinson Joseph A. , Tiedje James M.
Published: January 2020

Michaelis-Menten kinetic parameters for H
2
consumption by three methanogenic habitats were determined from progress curve and initial velocity experiments. The influences of mass transfer resistance, endogenous H
2
production, and growth on apparent parameter estimates were also investigated. Kinetic parameters could not be determined for undiluted rumen fluid and some digestor sludge from gas-phase measurements of H
2
, since mass transfer of H
2
across the gas-liquid interface was rate limiting. However, accurate values were obtained once the samples were diluted. H
2
consumption by digestor sludge with a long retention time and by hypereutrophic lake sediment was not phase transfer limited. The
K

m

values for H
2
uptake by these habitats were similar, with means of 5.8, 6.0, and 7.1 μM for rumen fluid, digestor sludge, and sediment, respectively.
V
max
estimates suggested a ratio of activity of approximately 100 (rumen fluid):10 (sludge):1 (sediment); their ranges were as follows: rumen fluid, 14 to 28 mM h
−1
; Holt sludge, 0.7 to 4.3 mM h
−1
; and Wintergreen sediment, 0.13 to 0.49 mM h
−1
. The principles of phase transfer limitation, studied here for H
2
, are the same for all gaseous substrates and products. The limitations and errors associated with gas phase determination of kinetic parameters were evaluated with a mathematical model that combined mass transport and Michaelis-Menten kinetics. Three criteria are described which can be used to evaluate the possibility that a phase transfer limitation exists. If it does not exist, (i) substrate consumption curves are Michaelis-Menten and not first order, (ii) the
K

m

is independent of initial substrate concentration, and (iii) the
K

m

is independent of biomass (
V
max
) and remains constant with dilution of sample. Errors in the Michaelis-Menten kinetic parameters are caused by endogenously produced H
2
, but they were <15% for rumen fluid and 10% for lake sediment and digestor sludge. Increases in
V
max
during the course of progress curve experiments were not great enough to produce systematic deviations from Michaelis-Menten kinetics.
Methane Production by Fermentor Cultures Acclimated to Waste from Cattle Fed Monensin, Lasalocid, Salinomycin, or Avoparcin
Authors: Varel V. H. , Hashimoto A. G.
Published: January 2020

The ability of microorganisms to ferment waste from cattle fed monensin, lasalocid, or salinomycin to methane was determined. Continuously mixed anaerobic fermentors with 3-liter working volumes at 55°C were used; fermentors were fed once per day. Initially, all fermentors were fed waste without antibiotics at 6% volatile solids (VSs, organic matter) and a 20-day retention time (RT) for 60 days. Waste from animals fed monensin, lasalocid, or salinomycin at 29, 20, and 16.5 mg per kg of feed, respectively, was added to duplicate fermentors at the above VSs, and RT. Avoparcin (5 to 45 mg/liter) was not fed to animals but was added directly to duplicate fermentors. Lasalocid and salinomycin had minimal effects on the rate of methane production at RTs of 20 days and later at 6.5 days. Avoparcin caused an increase in organic acids from 599 to 1,672 mg/liter (as acetate) after 4 weeks, but by 6 weeks, acid concentrations declined and the rate of methane production was similar to controls at a 6.5-day RT. The monensin fermentors stopped producing methane 3 weeks after antibiotic addition. However, after a 6-month acclimation period, the microorganisms apparently adapted, and methane production rates of 1.65 and 2.51 liters per liter of fermentor volume per day were obtained with 6% VSs, and RTs of 10 and 6.5 days, respectively. This compares with 1.78 and 2.62 liters/liter per day for controls (
P
> 0.05). All fermentors that were fed waste containing antibiotics had lower pH values and ammonia and alkalinity concentrations, suggesting less buffering capacity and protein catabolism than in controls. Acclimation results obtained with fermentors at 35°C were similar to those for fermentors at 55°C. These studies indicate that waste from cattle fed these selected growth-promoting antibiotics can be thermophilically fermented to methane at RTs of 6.5 days or longer and VS concentrations of 6%, at rates comparable to waste without antibiotics.
Characterization of rat cecum cellulolytic bacteria
Authors: Montgomery L , Macy J M
Published: January 2020

Cellulose-degrading bacteria previously isolated from the ceca of rats have been characterized and identified. The most commonly isolated type was rods identified as Bacteroides succinogenes. These bacteria fermented only cellulose (e.g., pebble-milled Whatman no. 1 filter paper), cellobiose, and in 43 of 47 strains, glucose, with succinic and acetic acids as the major products. The only organic growth factors found to be required by selected strains were p-aminobenzoic acid, cyanocobalamine, thiamine, and a straight-chain and a branched-chain volatile fatty acid. These vitamin requirements differ from those of rumen strains of B. succinogenes, indicating the rat strains may form a distinct subgroup within the species. The mole percent guanine plus cytosine was 45%, a value lower than those (48 to 51%) found for three rumen strains of B. succinogenes included in this study. Cellulolytic cocci were isolated less frequently than the rods and were identified as Rumminococcus flavefaciens. Most strains fermented only cellulose and cellobiose, and their major fermentation products were also succinic and acetic acids. Their required growth factors were not identified but were supplied by rumen fluid.
Ultrastructural Analysis of Spores and Parasporal Crystals Formed by
Bacillus sphaericus
2297
Authors: Yousten Allan A. , Davidson Elizabeth W.
Published: January 2020

Bacillus sphaericus
2297, growing from a boiled, relatively nontoxic spore inoculum, increased about 30-fold in toxicity for mosquito larvae during early exponential growth but showed an approximately 1,000-fold toxicity increase during the late-exponential phase, as spores began to appear in the culture. The development of spores in the bacterial cells was accompanied by the formation of parasporal crystals. These parasporal crystals appeared during stage III as the forespore septum engulfed the incipient forespore. The paraspores were separated from the forespores by a branch of the exosporium across the cell. Measurements of the parasporal substructure revealed a 6.3-nm distance between the striations. When spores and paraspores were fed to mosquito larvae and the larvae were fixed 15 min after feeding, it was found that the spores remained relatively unchanged but that the matrix of the paraspores was dissolved. After dissolution of the paraspore matrix, a meshlike envelope remained which retained the paraspore shape and which was often in contact with the cross-cell portion of the exosporium. The parasporal crystals may be a source of the mosquito larval toxin in this strain of
B. sphaericus
, but proof will require their isolation from other cellular components.
Effects of egg yolk and salt on Micrococcaceae heat resistance
Authors: Verrips T , van Rhee R
Published: January 2020

The heat resistance and growth possibilities of various members of the Micrococcaceae in egg yolk and egg yolk with added salt were determined. Egg yolk alone protected members of the Micrococcaceae considerably against heat. Whereas in water Staphylococcus aureus S6 had a decimal reduction time (D) value of 66 s at 55 degrees C, its D value in egg yolk at the same temperature was 246 s. In salted egg yolk (water activity, 0.95), S. aureus S6 had a D value of 180 s at 66 degrees C and was largely inactivated during the pasteurization processes currently applied. Micrococcus saprophyticus and S. epidermidis (D value of each under the same conditions, 390 s) could survive such treatments to a certain extent and can thus spoil commercial egg yolk.
Influence of spatial and temporal variations on organic pollutant biodegradation rates in an estuarine environment
Authors: Bartholomew G W , Pfaender F K
Published: January 2020

The influence of spatial and temporal environmental variations on rates of organic pollutant biodegradation were assessed by using heterotrophic uptake kinetics. These studies were conducted at three sites, representing the gradient from freshwater to estuarine to marine systems. Of the compounds tested, total uptake Vmax rates decreased in the order of nitrilotriacetic acid, m-cresol, chlorobenzene, and 1,2,4-trichlorobenzene. In general, the freshwater site exhibited the highest uptake rates, with somewhat lower rates at the estuarine site. Rates at the marine site were much lower than at the other sites, except during the winter. Metabolic rates at both the freshwater and estuarine areas were significantly decreased during periods of low water temperature. Rates at the marine site were relatively uniform throughout the year. Linear regression analysis was used to compare m-cresol biodegradation rates to characteristics of the microbial community, which included direct microscopic counts, CFU counts, and cellular incorporation of amino acids. The observed rates did not consistently correlate well with any of the measured characteristics of the microbial community.
Utilization of Enzymatically Hydrolyzed Wood Hemicelluloses by Microorganisms for Production of Liquid Fuels
Authors: Saddler John N. , Yu Ernest K. C. , Mes-Hartree Mary , Levitin Norm , Brownell Harold H.
Published: January 2020

Hemicellulose-derived sugars were obtained from a variety of pretreated wood substrates such as water-soluble fractions from steam-exploded aspen, solvent-extracted aspen, and commercial xylan. These fractions were enzymatically hydrolyzed by commercial enzyme preparations and by the culture filtrates of eight highly cellulolytic fungi. The sugars released were assayed by high-pressure liquid chromatography. Over 30% of the hemicellulose fractions, at a 10% substrate concentration, could be hydrolyzed to monosaccharides. These hemicellulose hydrolysates were used as the substrates for growth of
Clostridium acetobutylicum
and
Klebsiella pneumoniae.
Comparatively low butanol values were obtained with
C. acetobutylicum
, although over 50% of the hemicellulose fraction, at a 1% substrate concentration, could be converted to 2,3-butanediol, ethanol, and acetic acid by
K. pneumoniae.
Bacterial survival and association with sludge flocs during aerobic and anaerobic digestion of wastewater sludge under laboratory conditions
Authors: Farrah S R , Bitton G
Published: January 2020

The fate of indicator bacteria, a bacterial pathogen, and total aerobic bacteria during aerobic and anaerobic digestion of wastewater sludge under laboratory conditions was determined. Correlation coefficients were calculated between physical and chemical parameters (temperature, dissolved oxygen, pH, total solids, and volatile solids) and either the daily change in bacterial numbers or the percentage of bacteria in the supernatant. The major factor influencing survival of Salmonella typhimurium and indicator bacteria during aerobic digestion was the temperature of sludge digestion. At 28 degrees C with greater than 4 mg of dissolved oxygen per liter, the daily change in numbers of these bacteria was approximately -1.0 log10/ml. At 6 degrees C, the daily change was less than -0.3 log10/ml. Most of the bacteria were associated with the sludge flocs during aerobic digestion of sludge at 28 degrees C with greater than 2.4 mg of dissolved oxygen per liter. Lowering the temperature or the amount of dissolved oxygen decreased the fraction of bacteria associated with the flocs and increased the fraction found in the supernatant.
Properties of alkyl hydroxycinnamates and effects on Pseudomonas fluorescens
Authors: Baranowski J D , Nagel C W
Published: January 2020

Alkyl esters of six hydroxycinnamic acids, shown to be active antimicrobial agents when tested against Pseudomonas fluorescens, were further investigated for their effects against this organism. There was no statistically significant adaptation by this organism to either of the methyl esters of caffeic, rho-coumaric, cinnamic, or rho-hydroxybenzoic acids. Mixtures of these compounds taken two at a time gave at least additive effects, with some mixtures showing synergism. Preliminary work was also performed to determine the mode of inhibitory action for these compounds. The inhibition of oxygen utilization by the methyl esters correlated well with growth inhibition. Short-term lethality studies showed that none of the alkyl esters or methyl or propyl paraben produced any bacteriocidal effects. Oil-water partition coefficients were determined for these compounds and were shown to have no correlation with growth inhibitions. These all point to a specific mode of action, based in part on cellular energy depletion, rather than the nonspecific membrane-disrupting effects of other phenolic antimicrobial agents.
Concentration of coliphage from water and sewage with charge-modified filter aid
Authors: Singh S N , Gerba C P
Published: January 2020

Methods of detecting and concentrating animal viruses from large volumes of water and wastewater have experienced rapid development in recent years, but only a few methods are available for the concentration of bacteriophages. The present study describes the use of a charge-modified (Zeta Plus) filter aid (AMF Cuno, Meriden, Conn.) for the concentration of coliphages from large volumes of water and sewage. Coliphages MS-2 and f2 were efficiently adsorbed from water and sewage to the positively charged filter aid. Elution was accomplished with 4% beef extract--0.5 M NaCl adjusted to pH 9.5. The recovery of f2 from 10- to 20-liter volumes of tap water ranged between 11 and 70%, and the recovery of MS-2 ranged between 43 and 70%. The efficiency of recovery of naturally occurring coliphages from secondarily treated sewage ranged between 16 and 44%. This technique appears to be promising because it requires low-cost equipment (47-mm polypropylene filter housing), is easy to handle, and can filter large volumes of water (greater than or equal to 20 liters) with good recoveries. Filtrations can be conducted at the ambient pH of the water, and the unit cost per filtration (i.e., the cost of filter aid) comes to less than three cents per sampling. The technique could be useful in evaluation of viral water quality, study of ecology and occurrence of phages in natural waters, and isolation of rare phages from natural waters.
Rapid Detection of
Salmonella
spp. by Using Felix-O1 Bacteriophage and High-Performance Liquid Chromatography
Authors: Hirsh Dwight C. , Martin Lori D.
Published: January 2020

A method is described whereby the presence of
Salmonella
spp. can be detected within 8 to 24 h of sample collection. The method depends upon the interaction of
Salmonella
spp. with the
Salmonella
-specific Felix-O1 bacteriophage. This interaction results in an increase in concentration of the bacteriophage which is detected by high-performance liquid chromatographic techniques.
Dialysis Membrane Technique for Studying Microbial Interaction
Authors: Nordbring-Hertz B.
Published: January 2020

A dialysis membrane method is described which allows (i) cultivation of fungi on an agar support, (ii) observation of growth and development by direct light microscopy, (iii) transfer of cultures from agar surfaces for subsequent treatments or for biochemical analysis, and (iv) preparation for scanning electron microscopy. The method is used routinely in studies of fungus-nematode and fungus-fungus interactions.
Stability of
Methanobrevibacter smithii
Populations in the Microbial Flora Excreted from the Human Large Bowel
Authors: Miller Terry L. , Wolin Meyer J.
Published: January 2020

Total anaerobic bacteria and
Methanobrevibacter smithii
populations were enumerated in fecal specimens from two individuals over 10- and 13-month periods. The ratio of
M. smithii
to total anaerobic count varied between the individuals, but it was a relatively constant proportion of the large-bowel microbial flora within each individual. Neither a barium enema examination of one subject nor a radical change in the diet of the other had any long-term effect on the methanogen populations.
Isolation of
Vibrio cholerae
Serotype Ogawa from a Florida Estuary
Authors: Motes M. L. , Zywno S. R. , DePaola A. , Becker R. E. , Presnell M. W.
Published: January 2020

Vibrio cholerae
serotype Ogawa was recently isolated from the estuarine waters of Apalachicola Bay, Fla., in areas that are subject to consistent fecal contamination and in areas that are remote from any apparent source of contamination. The significance of these organisms in the environment has not been determined.
Distribution of Pseudomonas aeruginosa in a riverine ecosystem
Authors: Pellett S , Bigley D V , Grimes D J
Published: January 2020

The distribution of Pseudomonas aeruginosa in navigation pool 8 of the upper Mississippi River was investigated by acetamide broth enrichment of water, sediment, and swab (solid-water interface) samples. Among the 152 P. aeruginosa isolates, serological type 1 was most prevalent (34.2%), and a small number (13.2%) showed carbenicillin resistance. Pigmentation was variable, with only 44.7% elaborating typical blue-green pigment. P. aeruginosa was most commonly isolated from sediment, with solid-water interfaces (aufwuchs samples) also exhibiting high frequencies of isolation. Current velocity, oxygen and nutrient availability, surface tension, desiccation, and negative phototropism were important factors in the riverine distribution of this epibacterium.
Legionella incidence and density in potable drinking water supplies
Authors: Tison D L , Seidler R J
Published: January 2020

The incidence and density of Legionella spp. in raw water, water at various stages of treatment, and in potable distribution water were determined by direct immunofluorescence. The number of cells reacting with Legionella-specific fluorescent antibody conjugates in raw waters ranged from about 10(4) to 10(5) cells/liter, whereas the concentrations of fluorescent antibody-positive cells in the distribution waters were generally 10- to 100-fold lower than in the raw source waters. No viable or virulent Legionella strains were isolated from either the source or distribution waters. However, Legionella spp. are infrequently isolated from water at temperatures below 15 degrees C as was the case in the system surveyed in this study.
Differentiation of
Clostridium difficile
Toxin from
Clostridium botulinum
Toxin by the Mouse Lethality Test
Authors: Gilligan Peter H. , Brown Lawrence , Berman Richard E.
Published: January 2020

The mouse lethality test is the most sensitive method for confirming the diagnosis of infant botulism. Both
Clostridium difficile
and
Clostridium botulinum
produce heat-labile toxins which are lethal for mice and can be found in the feces of infants. These two toxins can be distinguished from one another in this assay when both are present in the same fecal specimen because they appear to be immunologically distinct toxins.
Bacteriostatic and bactericidal modes of action of bis(tributyltin)oxide on Legionella pneumophila
Authors: Soracco R J , Pope D H
Published: January 2020

The modes of action of bis(tributyltin)oxide (TBTO) doses between 1 X 10(4) and 6 X 10(7) molecules per cell on a single environmental isolate of Legionella pneumophila were studied by monitoring the following parameters: (i) growth, (ii) cell viability, (iii) 14C-amino acid incorporation, (iv) 14CO2 production from 14C-amino acids, (v) [3H]uridine incorporation, (vi) [3H]thymidine incorporation, (vii) oxygen consumption, (viii) cellular ATP levels, and (ix) adenylate energy charge. The amount of TBTO associated with the cells in these laboratory cultures was also compared with that remaining in the suspending medium. Most of the TBTO (68 to 88%) was found to be associated with the cells. This result explained why the cellular responses which were measured did not correlate with the TBTO concentration, but rather with the dose of TBTO to which the cells were exposed. At the lower TBTO doses tested (10(4) to 10(7) molecules per cell) a log-normal relationship was observed between the reduction in growth rate and the TBTO concentration. At intermediate TBTO doses (ca. 10(7) molecules per cell) growth stasis occurred, with nearly 100% of the cells in these cultures remaining viable for at least 5 h after treatment. The cellular function which seemed to be primarily affected at these levels of TBTO was the energy conversion mechanism, since the decline in the rates of CO2 production, oxygen consumption, and macromolecular synthesis was preceded by an immediate (within 1 min) drop in the intracellular levels of ATP and the adenylate energy charge. At the higher TBTO doses greater than 10(7) molecules per cell) an initial, precipitous, drop in the number of viable cells was observed, which was followed by a further exponential reduction of viable cells in the treated culture. This dramatic increase in bactericidal activity with a slight increase in the TBTO dose indicated that the modes of bacteriostatic and bactericidal action of TBTO were different.
Polymeric Beta-Hydroxyalkanoates from Environmental Samples and
Bacillus megaterium
Authors: Findlay Robert H. , White David C.
Published: January 2020

The procaryotic endogenous storage polymer known as poly-beta-hydroxybutyrate is actually a mixed polymer of short-chain beta-hydroxy fatty acids. A method for the quantitative recovery of this mixed polymer, called poly-beta-hydroxyalkanoate (PHA), with analysis by capillary gas-liquid chromatography, showed the presence of at least 11 short-chain beta-hydroxy acids in polymers extracted from marine sediments. Polymers extracted from
Bacillus megaterium
monocultures were also a complex mixture of beta-hydroxy acids with chain lengths between four and eight carbons. Lyophilized sediments were extracted in a modified Soxhlet extractor, and the polymer was purified with ethanol and diethyl ether washes. The purified polymer was treated with ethanol-chloroform-hydrochloric acid (8.5:2.5:1) for 4 h at 100°C, a treatment which resulted in the formation of the ethyl esters of the constituent beta-hydroxy acids. Subsequent assay of the products by gas-liquid chromatography indicated excellent reproducibility and sensitivity (detection limit, 100 fmol). Disturbing sediments mechanically or adding natural chelators increased all major PHA components relative to the bacterial biomass. Gardening of sedimentary microbes by
Clymenella
sp., an annelid worm, induced decreases in PHA, with changes in the relative proportion of component beta-hydroxy acids. The concentration of PHA relative to the bacterial biomass can reflect the recent metabolic status of the microbiota.
Toxic effects of ochratoxin A and citrinin, alone and in combination, on chicken embryos
Authors: Veselá D , Veselý D , Jelínek R
Published: January 2020

The embryotoxic potential of ochratoxin A and citrinin was studied after administering, either subgerminally or intraamniotically, single mounting doses of the mycotoxins to chicken embryos on days 2, 3, and 4. The beginning of the embryotoxicity dose range was found to be between 0.01 to 0.05 microgram for ochratoxin A and 1 to 10 micrograms for citrinin. The maximum response to both mycotoxins occurred after administration on day 3. In addition to significant growth retardation of fetuses, exencephaly, microphthalmia, cleft beak, reduction deformities of the limbs, and abdominal wall and ventricular septal defects were encountered on day 8 of incubation. When 4 micrograms of citrinin was constantly added to ochratoxin A administered in the dose range of 0.03 to 0.5 microgram, a strictly additive effect was seen. It may be supposed that citrinin produced together with ochratoxin A in some strains of Penicillium viridicatum Westling does not potentiate the clear-cut embryotoxic action of the latter mycotoxin.
Anaerobic Degradation of Cyanuric Acid, Cysteine, and Atrazine by a Facultative Anaerobic Bacterium
Authors: Jessee J. A. , Benoit R. E. , Hendricks A. C. , Allen G. C. , Neal J. L.
Published: January 2020

A facultative anaerobic bacterium that rapidly degrades cyanuric acid (CA) was isolated from the sediment of a stream that received industrial wastewater effluent. CA decomposition was measured throughout the growth cycle by using a high-performance liquid chromatography assay, and the concomitant production of ammonia was also measured. The bacterium used CA or cysteine as a major, if not the sole, carbon and energy source under anaerobic, but not aerobic, conditions in a defined medium. The cell yield was greatly enhanced by the simultaneous presence of cysteine and CA in the medium. Cysteine was preferentially used rather than CA early in the growth cycle, but all of the CA was used without an apparent lag after the cysteine was metabolized. Atrazine was also degraded by this bacterium under anaerobic conditions in a defined medium.
Avian wildlife reservoir of Campylobacter fetus subsp. jejuni, Yersinia spp., and Salmonella spp. in Norway
Authors: Kapperud G , Rosef O
Published: January 2020

Cloacal swabs from 540 wild-living birds were cultured for Campylobacter fetus subsp. jejuni, Yersinia spp., and Salmonella spp. The carrier rates detected were as follows: C. fetus subsp. jejuni, 28.4%; Yersinia spp., 1.2%; and Salmonella spp., 0.8%. All birds were apparently healthy when captured. C. fetus subsp. jejuni was isolated from 11 of the 40 bird species examined. Among birds inhabiting the city of Oslo, the highest isolation rate was found in crows (Corvus corone cornix) (89.8%), followed by gulls (Larus spp.) (50.0%) and domestic pigeons (Columba livia domesticus) (4.2%). The gulls and crows scavenge on refuse dumps. High carrier rates were also detected among the following birds from nonurban, coastal areas: puffin (Fratercula arctica) (51.3%), common tern (Sterna hirundo) (5.6%), common gull (Larus canus) (18.9%), black-headed gull (Larus ridibundus) (13.2%), and herring gull (Larus argentatus) (4.2%). The list of species harboring C. fetus subsp. jejuni also includes the Ural owl (Strix uralensis), goldeneye (Bucephala clangula), and reed bunting (Emberiza schoeniclus). The following five Yersinia strains were isolated: Y. kristensenii (two strains), Y. intermedia (two strains), and "Yersinia X2" (one strain). Four strains belonging to the genus Salmonella were isolated from three different species of gulls. These isolates were identified as S. typhimurium, S. indiana, and S. djugu. The results indicate that campylobacters are a normal component of the intestinal flora in several bird species, whereas Salmonella and Yersinia carriers are more sporadic.
Biosynthesis of radiolabeled phomopsin by Phomopsis leptostromiformis
Authors: Payne A L
Published: January 2020

[14C]phomopsin and [36Cl]phomopsin were synthesized by Phomopsis leptostromiformis in liquid cultures containing various labeled compounds. [U-14C]isoleucine, [U-14C]phenylalanine, and [U-14C]proline were the best precursors in terms of labeling efficiency, whereas [36Cl]hydrochloride was much less efficient. When each of the four precursors was used, a large proportion of recovered label was associated with phomopsin. The specific activities of phomopsin produced with labeled isoleucine, phenylalanine, proline, and hydrochloride were 150, 120, 90, and 17 muCi/mmol, respectively. 14C label from acetate, malate, propionate, sucrose, or tryptophan was neither specifically nor efficiently incorporated into phomopsin.
Detection of microbial proteolytic activity by a cultivation plate assay in which different proteins adsorbed to a hydrophobic surface are used as substrates
Authors: Wikström M B
Published: January 2020

A screening technique for microbial proteases, the thin-layer enzyme assay cultivation technique, was developed. The inner surface of a polystyrene petri dish was coated with protein and then covered with a culture agar medium. The enzymes, produced during growth of the microorganisms, reach the protein-coated surface by diffusion in the agar. Degradation of the protein was visualized by condensation of water vapor on the surface after removal of the agar medium. The wettability of the enzyme-affected protein-coated polystyrene surface was decreased compared with the unaffected protein surface. Enzyme substrates used were fibrinogen, immunoglobulin G, egg albumin, human serum albumin, bovine serum albumin, hemoglobin, mucin, and gelatin. It was possible to use a variety of culture agar media, nonselective as well as selective, in the assay. The technique provides a sensitive, convenient, and inexpensive method for screening various microbial proteases. In addition, the technique can be used for screening proteolytic enzyme activity of specific microbial species in a mixed microbial sample as well as for studies of factors that influence the cultivation conditions for protease production and activity.
Medium for presumptive identification of Yersinia enterocolitica
Authors: Weagant S D
Published: January 2020

A medium, lysine-arginine-iron agar, was developed for the presumptive identification of Yersinia enterocolitica isolates. This medium was a modification of lysine-iron agar and allowed for the testing of five biochemical characteristics in a single tube medium. The reactions of Y. enterocolitica on this medium were reliable and distinctive. The medium significantly simplified the identification of Y. enterocolitica isolates.
Betaine: New Oxidant in the Stickland Reaction and Methanogenesis from Betaine and
l
-Alanine by a
Clostridium sporogenes-Methanosarcina barkeri
Coculture
Authors: Naumann Evelyn , Hippe Hans , Gottschalk Gerhard
Published: January 2020

Growing and nongrowing cells of
Clostridium sporogenes
fermented betaine with
l
-alanine,
l
-valine,
l
-leucine, and
l
-isoleucine as electron donors in a coupled oxidation-reduction reaction (Stickland reaction). For the substrate combinations betaine and
l
-alanine and betaine and
l
-valine balance studies were performed; the results were in agreement with the following fermentation equation: 1 R- CH(NH
2
)-COOH + 2 betaine + 2 H
2
O → 1 R-COOH + 1 CO
2
+ 1 NH
3
+ 2 trimethylamine + 2 acetate. Growth and production of trimethylamine were strictly dependent on the presence of selenite in the medium. With cell suspensions it was shown that
C. sporogenes
was unable to catabolize betaine as a single substrate. Betaine, however, was reduced to trimethylamine and acetate under an atmosphere of molecular hydrogen. For the reduction of betaine by cell extracts of
C. sporogenes
, dimercaptans such as 1,4-dithiothreitol could serve as electron donors. No betaine reductase activity was detected in cells grown in a complex medium without betaine. The pH optimum of betaine reductase was at pH 7.3. When
C. sporogenes
was cocultured with
Methanosarcina barkeri
strain Fusaro on betaine together with
l
-alanine, an almost complete conversion of the two substrates to CH
4
, NH
3
, and presumably CO
2
was observed.
Microbial Transformation of Squalene: Terminal Methyl Group Oxidation by
Corynebacterium
sp
Authors: Seo Chull Won , Yamada Yasuhiro , Takada Nobuo , Okada Hirosuke
Published: January 2020

Corynebacterium
sp. strain SY-79 was isolated from soil, using squalene as a carbon source. Microbiological properties of this bacterium are described. The metabolic product of this bacterium from squalene was identified as 2,6,10,15,19, 23-hexamethyl-2,6,10,14,18,22-tetracosahexaenedioic acid (squalenedioic acid).