bluuebunny/crossref_metadata_2025 huggingface dataset:
Enumeration and selective isolation of rumen spirochetes
Authors: Stanton T B , Canale-Parola E
Published: January 2020

Enumeration by means of light microscopy showed that from 0.4 x 10(8) to 2.0 x 10(8) spirochetes were present per ml of bovine rumen fluid. Viable cell counts yielded slightly lower values, ranging from 0.1 x 10(8) to 1.2 x 10(8) spirochetes per ml of rumen fluid. The antibiotic rifampin, which served as a selective agent for rumen spirochetes, was added to agar media used in the estimation of viable spirochete numbers in rumen fluid. Morphologically diverse spirochetes were isolated from rumen fluid by means of a procedure involving the use of rifampin as a selective agent in agar media. The strains isolated represented seven morphological types of spirochetes differing in cell size, cell coiling pattern, and number of periplasmic fibrils per cell. Electron microscopy showed that the number of periplasmic fibrils present in the different morphological types of rumen spirochetes ranged from 2 to more than 20 per cell. The results of this study indicate that the bovine rumen is a highly favorable environment for a number of morphologically diverse spirochetes.
Description of a bacteriocinogenic plasmid in Beneckea harveyi
Authors: McCall J O , Sizemore R K
Published: January 2020

A total of 795 strains of marine Vibrio species and Beneckea harveyi, a luminescent marine bacterium, were isolated from various sources in the area of Galveston Island, Tex., and screened for the production of bacteriocin-like substances. More than 8% of the Vibrio isolates produced low-molecular-weight (dialyzable) substances, which were lethal to a test strain of V. parahaemolyticus. Approximately 5% of the B. harveyi isolates produced higher-molecular-weight (nondialyzable) substances which were lethal to a test strain of B. harveyi. One of the B. harveyi strains (strain SY) produced a nondialyzable substance which was lethal to two of 39 strains of B. harveyi. The substance showed no activity toward 17 test strains drawn from the Vibrionaceae and Enterobacteriaceae. Strain SY showed no sensitivity to its own lethal agent and was shown by agarose gel electrophoresis and electron microscopy to harbor a single plasmid of 38 x 10(6) daltons. Variants of strain SY lacking the plasmid were produced by growth in the presence of the antibiotic novobiocin. These variants lacked both the ability to produce the lethal substance and the ability to survive in its presence. The lethal agent produced by strain SY is the first bacteriocin reported in marine bacteria. The term "harveyicin" is proposed to name this lethal substance.
Viral aggregation: mixed suspensions of poliovirus and reovirus
Authors: Floyd R
Published: January 2020

The aggregation of mixtures of two dissimilar viruses, poliovirus I (Mahoney) and reovirus III (Dearing), was followed by electron microscopy under conditions known to induce either aggregation or dispersion of each virus separately. Neither virus aggregated at pH 7 in an appropriate buffer, and no mixed aggregates were formed. Under conditions of lowered ionic strength (by dilution into distilled water) poliovirus became aggregated, whereas reovirus did not, and again no mixed aggregates were formed. At pH 6, however, poliovirus again aggregated and, although reovirus did not, it attached to poliovirus aggregates. Thus, some inducement toward aggregation was necessary to cause formation of mixed aggregates. This inducement probably took the form of a reduction of the ionic double layer surrounding the particles, which is known to occur at low pH. At pH 5 and below both viruses aggregated severely, and large mixed aggregates were formed. These mixed aggregates could be broken up by neutralization of the suspension, although small aggregates of poliovirus remained. Reovirus showed a marked tendency to attach to large clumps of poliovirus, but the reverse tendency was not observed. The results indicate that mixed aggregates may be of significance in the isolation of viruses from water or wastewater.
Isolation and Characterization of a Thermophilic Strain of
Methanosarcina
Unable to Use H
2
-CO
2
for Methanogenesis
Authors: Zinder Stephen H. , Mah Robert A.
Published: January 2020

A thermophilic strain of
Methanosarcina,
designated
Methanosarcina
strain TM-1, was isolated from a laboratory-scale 55°C anaerobic sludge digestor by the Hungate roll-tube technique. Penicillin and
d
-cycloserine, inhibitors of peptidoglycan synthesis, were used as selective agents to eliminate contaminating non-methanogens.
Methanosarcina
strain TM-1 had a temperature optimum for methanogenesis near 50°C and grew at 55°C but not at 60°C. Substrates used for methanogenesis and growth by
Methanosarcina
strain TM-1 were acetate (12-h doubling time), methanol (7- to 10-h doubling time), methanol-acetate mixtures (5-h doubling time), methylamine, and trimethylamine. When radioactively labeled acetate was the sole methanogenic substrate added to the growth medium, it was predominantly split to methane and carbon dioxide. When methanol was also present in the medium, the metabolism of acetate shifted to its oxidation and incorporation into cell material. Electrons derived from acetate oxidation apparently were used to reduce methanol. H
2
-CO
2
was not used for growth and methanogenesis by
Methanosarcina
strain TM-1. When presented with both H
2
-CO
2
and methanol,
Methanosarcina
strain TM-1 was capable of limited hydrogen metabolism during growth on methanol, but hydrogen metabolism ceased once the methanol was depleted.
Methanosarcina
strain TM-1 required a growth factor (or growth factors) present in the supernatant of anaerobic digestor sludge. Growth factor requirements and the inability to use H
2
-CO
2
are characteristics not found in other described
Methanosarcina
strains. The high numbers of
Methanosarcina
-like clumps in sludges from thermophilic digestors and the fast generation times reported here for
Methanosarcina
TM-1 indicate that
Methanosarcina
may play an important role in thermophilic methanogenesis.
Sublethal stress in Escherichia coli: a function of salinity
Authors: Anderson I C , Rhodes M , Kator H
Published: January 2020

Sublethal stress in Escherichia coli was detected in various test media after exposure (in vitro) to seawater of various salinites. Stress was measured with an electrochemical detection technique and a beta-galactosidase assay. Test media included EC medium, medium A-1, and tryptic soy broth modified to contain lactose for beta-galactosidase assay experiments. Stress was defined as the difference between a predicted electrochemical response time calculated for unstarved cells from a standard curve and the observed electrochemical response time for cells starved in seawater. The higher the salinity, the greater the stress for all test media examined. Stress was most pronounced in EC and was attributed primarily to initial die-off of starved cells exposed to the test medium at the elevated temperature of 44.5 degrees C. Lag time and growth rates in test media were not significantly affected by salinity. beta-Galactosidase specific activity, assayed in starved cells after transfer to an induction medium at 44.5 degrees C for 150 min, was inversely related to the salinity of the starved cell suspension. The consequences of these observations with respect to coliform enumeration methods are discussed.
Estimation of Biodegradation Potential of Xenobiotic Organic Chemicals
Authors: Larson Robert J.
Published: January 2020

A method is described to estimate the biodegradation potential of soluble, insoluble, and unknown organic chemicals. The method consists of two stages: (i) generation of a microbial inoculum in a bench scale semicontinuous activated sludge system during which microorganisms are acclimated to test material and the removal of dissolved organic carbon is monitored and (ii) biodegradability testing (CO
2
evolution) in a defined minimal medium containing the test material as the sole carbon and energy source and a dilute bacterial inoculum obtained from the supernatant of homogenized activated sludge generated in the semicontinuous activated sludge system. Removal and biodegradation are measured using nonspecific methods, at initial concentrations of 5 to 10 mg of dissolved organic carbon per liter. Biodegradability data are accurately described by a nonlinear computer model which allows the rate and extent of biodegradation for different compounds to be compared and statistically examined. The evaluation of data generated in the combined removability-biodegradability system allows the biodegradation potential of a variety of xenobiotic organic chemicals to be estimated.
Nondividing, Bacteroid-Like
Rhizobium trifolii
: In Vitro Induction Via Nutrient Enrichment
Authors: Urban James E.
Published: January 2020

Rhizobium trifolii
0403 maintained in exponential phase via periodic dilution doubled in 210 min in mannitol-salts medium and doubled in 244 min in glycerolsalts. In both media, cell number and optical density increased in parallel. When exponentially growing cells in either medium were supplemented with a mixture of glucose, Casamino Acids, succinate, and yeast extract, optical density continued to increase but within less than the time required for one doubling, division ceased. The increase in optical density coupled with division cessation resulted in the formation of large, pleomorphic, nondividing cells. Large cells apparently increased in size as a result of swelling only at regions of most recent cell envelope synthesis. Greater than 95% of the cells in a population swelled, and commitment to swelling occurred within two doubling time equivalents. Swollen cells eventually reached a characteristic maximum size and exhibited osmotic fragility.
Study of Developmental Stages of
Methylosinus trichosporium
with the Aid of Fluorescent-Antibody Staining Techniques
Authors: Reed William M. , Dugan Patrick R.
Published: January 2020

When stained by using an indirect fluorescent-antibody technique,
Methylosinus trichosporium
displayed an uneven fluorescence. Exospores and the polar tips of some vegetative cells displayed a more intense fluorescence than the other cells. Cross-absorption of the specific anti-
M. trichosporium
immunoglobulin G with exospores resulted in no fluorescence of exospores or exospore regions of sporulating vegetative cells. This demonstrated that antigens were present on exospores and exospore regions of vegetative cells that are different from vegetative cell antigens. Taking advantage of this phenomenon, three fluorescentantibody staining techniques were developed which were used to study the life cycle of
M. trichosporium
.
Stability of simian rotavirus in fresh and estuarine water
Authors: Hurst C J , Gerba C P
Published: January 2020

The rates of inactivation of poliovirus 1, echovirus 7, coxsackievirus B3, and simian rotavirus SA11 were compared in polluted and nonpolluted fresh and estaurine water samples. The study was done in two parts, comparing virus survival in samples taken 1 year apart from the same sites. The survival studies were performed at 20 degrees C and at the natural pH of the water samples. In the first part of the study, the time required for a 3-log10 reduction in the initial virus titers was 2 to 3 days in the estaurine water samples and varied from 3 to greater than 14 days in the freshwater samples. In the second part of the study, no clear distinction was found between survival of viruses in freshwater samples and survival in estaurine water samples. The time required for a 3-log10 reduction in the initial virus titers in the second part of the study varied from 12 to greater than 14 days. This indicates that there is a nonseasonal change in factors in the water which affect virus survival. In this study SA11 survival time (used as a model for human virus) was well within the range exhibited by the enteroviruses, indicating that it also is environmentally stable in natural waters.
Indicator Technique for Antimetabolic Toxin Production by Phytopathogenic Species of
Pseudomonas
Authors: Gasson Michael J.
Published: January 2020

A simple bacteriological technique involving inhibition zone production on a lawn of
Escherichia coli
was developed to detect antimetabolite toxin production by phytopathogenic species of
Pseudomonas.
It was established that the mechanism of
E. coli
inhibition paralleled that of phytotoxin-induced chlorosis of plant tissue. Derivatives of
Pseudomonas tabaci
and
Pseudomonas phaseolicola
which did not produce antimetabolite were readily identified by use of this technique. The presence of plasmid DNA in
P. tabaci
strains was demonstrated, but no physical evidence for plasmid involvement in tabtoxin production was found. The role of antimetabolite production in the pathogenicity of
P. phaseolicola
was also investigated. The method was extended to show that strains of
P. maculicola, P. syringae
, and
P. coronofaciens
also produce antimetabolites.
Gastrointestinal ecology and histology of rats monoassociated with anaerobic bacteria
Authors: Wells C L , Balish E
Published: January 2020

Pure cultures of anaerobic bacteria colonized the gastrointestinal tracts of germfree rats and induced an increase in the cellularity of intestinal tissue.
Storage stability of Bacillus subtilis ethylene oxide biological indicators
Authors: Reich R R
Published: January 2020

Bacillus subtilis biological indicators, stored at ambient and freezer conditions for 24 months, demonstrated no statistical difference in ethylene oxide resistance and spore viability from initial production levels.
Semielectronic turbidimeter for automated monitoring of bacterial growth in test tubes
Authors: Marcelis J H , Versteeg H , Beck H J , Vinke D
Published: January 2020

An automated turbidimeter for measuring bacterial growth in ordinary test tubes is described. The device records and prints adsorbance, expressed as Klett units, of 60 cultures every 15 min. Provision is made for either aerobic or anaerobic incubation. The device is adaptable to modification, depending upon local requirements and availability of computation facilities.
Production and Biological Activity of Secalonic Acid D
Authors: Ciegler Alex , Hayes A. Wallace , Vesonder Ronald F.
Published: January 2020

Twenty isolates of
Penicillium oxalicum
produced secalonic acid as their major secondary metabolite. Fermentation conditions were determined for toxin production in grain and liquid media. The 50% lethal dose value for mice ranged from 26.5 to 51.7 mg/kg dependent on animal strain and sex, males being more susceptible than females. Secalonic acid was nontoxic and nonteratogenic to the chicken embryo and exhibited poor antibiotic properties. Its potential role in mycotoxicoses is discussed.
Promotion of Infection Thread Formation by Substances from
Rhizobium
Authors: Higashi Shiro , Abe Mikiko
Published: January 2020

An extrinsic substance (ES-6000) was isolated from the periplasmic space of
Rhizobium trifolii
(strain 4S) cells by osmotic shock, using a high-density sucrose solution. This substance promoted infection thread formation in root hairs of white clover when inoculated together with the infectious strain (4S). However, ES-6000 obtained from another rhizobial species and from strain A1, which is a noninfectious mutant strain obtained from strain 4S, did not have this effect. The promoter in the ES-6000 from strain 4S is a relatively small molecule since it passed through a hollow-fiber membrane (molecular weight, 6,000). This substance was also recognized as an
R

f

0.1 fraction by paper chromatography. Sucrose was effective in promoting nodulation and root elongation.
Kinetics of Growth and Amylase Production of
Saccharomycopsis fibuligera
on Potato Processing Wastewater
Authors: Lemmel S. A. , Heimsch R. C. , Korus R. A.
Published: January 2020

The kinetics of growth and amylase production of
Saccharomycopsis fibuligera
were studied in a chemostat on a synthetic potato processing blancher water. Dilution rates (
D
) from 0.101 to 0.480 h
−1
were examined. A mathematical model based on the Monod equation was developed. The yield of cell mass from carbohydrates was constant and equal to 0.84. The maximum specific growth rate and the Monod constant were determined to be 0.596 h
−1
and 0.226 mg/ml, respectively. An equation for the steady-state starch concentrations was empirically derived. The steady-state noncarbohydrate carbon levels rose linearly with
D.
Reducing sugars were the growth-limiting substrate, and their steady-state levels conformed to Monod kinetics. The yield of amylase from the cell mass (

Y
z

) declined as
D
rose and was described by the equation

Y
z

= (−8.005
D
+ 4.076). The model predicted that the maximum production of cell mass should occur at
D
= 0.35 h
−1
and the maximum production of amylase should occur at
D
= 0.22 h
−1
. The mathematical model presented agreed with the experimental results in its prediction of the steady-state level of reducing sugar, starch, cell mass, and amylase concentrations as well as the productivity of amylase.
Growth of Fish Cell Lines on Microcarriers
Authors: Nicholson Bruce L.
Published: January 2020

Microcarrier beads were evaluated as substrates for the propagation of five anchorage-dependent fish cell lines. Growth of rainbow trout gonad (RTG-2) and Atlantic salmon cells was limited on microcarriers maintained in suspension. However, stationary microcarriers were suitable substrates for the growth of RTG-2, AS, Chinook salmon embryo (CHSE-214), and fathead minnow cells. Cell yields ranged from 2 × 10
6
to 2.9 × 10
6
cells per ml, representing 7- to 10-fold increases over the initial cell concentrations. The yield of new RTG-2 cells per unit volume of growth medium was 2.8 times greater in microcarrier cultures than in standard monolayer cultures. Northern pike cells failed to grow on microcarriers. Yields of infectious pancreatic necrosis virus propagated in microcarrier cultures of RTG-2 cells were more than twice the yields in standard monolayer cultures. The greater economy of microcarrier cultures in terms of growth vessel and medium requirements holds great promise for the large-scale production of anchorage-dependent fish cell cultures and fish viruses.
Rapid Membrane Filtration-Epifluorescent Microscopy Technique for Direct Enumeration of Bacteria in Raw Milk
Authors: Pettipher Graham L. , Mansell Roderick , McKinnon Charles H. , Cousins Christina M.
Published: January 2020

Membrane filtration and epifluorescent microscopy were used for the direct enumeration of bacteria in raw milk. Somatic cells were lysed by treatment with trypsin and Triton X-100 so that 2 ml of milk containing up to 5 × 10
6
somatic cells/ml could be filtered. The majority of the bacteria (ca. 80%) remained intact and were concentrated on the membrane. After being stained with acridine organe, the bacteria fluoresced under ultraviolet light and could easily be counted. The clump count of orange fluorescing cells on the membrane correlated well (
r
= 0.91) with the corresponding plate count for farm, tanker, and silo milks. Differences between counts obtained by different operators and between the membrane clump count and plate count were not significant. The technique is rapid, taking less than 25 min, inexpensive, costing less than 50 cents per sample, and is suitable for milks containing 5 × 10
3
to 5 × 10
8
bacteria per ml.
Dichloran-glycerol medium for enumeration of xerophilic fungi from low-moisture foods
Authors: Hocking A D , Pitt J I
Published: January 2020

A low water activity (alpha omega) medium (0.95 alpha omega) containing 18% (wt/wt) glycerol and 2 micrograms of dichloran per ml was developed for enumerating the fungal flora of dried and semidried foods. The medium, designated DG18, was shown to be significantly better than Christensen malt salt agar when both media were tested with foodstuffs and with pure culture inocula. The need for a medium of reduced alpha omega for enumerating xerophilic fungi from low-moisture foods was demonstrated by comparing fungal counts obtained on both high-alpha omega and low-alpha omega media.
Concentration of Seeded Simian Rotavirus SA-11 from Potable Waters by Using Talc-Celite Layers and Hydroextraction
Authors: Ramia Sami , Sattar Syed A.
Published: January 2020

There is mounting evidence for the waterborne transmission of diarrhea caused by rotaviruses. As a result, proper techniques are required for their recovery from samples of incriminated water. The combined efficiency of the talc-Celite technique and polyethylene glycol 6000 hydroextraction was, therefore, tested for this purpose, using Simian rotavirus SA-11 and MA-104 cells. Conditioning of the dechlorinated tap water samples was carried out by pH adjustment to 6.0 and the addition of Earle balanced salt solution to a final concentration of 1:100. Passage of a 1-liter volume of such a conditioned sample through a layer containing a mixture of talc (300 mg) and Celite 503 (100 mg) led to the adsorption of nearly 93% of the added SA-11 plaque-forming units. For the recovery of the layer-adsorbed virus, 3% beef extract and 1× tryptose phosphate broth were found to be superior to a variety of other eluents tested. When we tested 100-liter sample volumes, layers containing 1.2 g of talc and 0.4 g of Celite were employed. Virus elution was carried out with 100 ml of tryptose phosphate broth. The eluate was concentrated 10-fold by overnight (4°C) hydroextraction with polyethylene glycol. With a total input virus of 7.0 × 10
5
and 1.4 × 10
2
plaque-forming units, the recoveries were about 71 and 59%, respectively.
Evaluation of a rapid method for the quantitative estimation of coliforms in meat by impedimetric procedures
Authors: Martins S B , Selby M J
Published: January 2020

A 24-h instrumental procedure is described for the quantitative estimation of coliforms in ground meat. The method is simple and rapid, and it requires but a single sample dilution and four replicates. The data are recorded automatically and can be used to estimate coliforms in the range of 100 to 10,000 organisms per g. The procedure is an impedance detection time (IDT) method using a new medium, tested against 131 stock cultures, that markedly enhances the impedance response of gram-negative organisms, and it is selective for coliforms. Seventy samples of ground beef were analyzed for coliforms by the IDT method and the conventional three-dilution, two-step most-probable-number test tube procedure. Seventy-nine percent of the impedimetric estimates fell within the 95% confidence limits of the most-probable-number values. This corresponds to the criteria used to evaluate other coliform tests, with the added advantage of a single dilution and more rapid results.
Effect of ionic environment on the inactivation of poliovirus in water by chlorine
Authors: Sharp D G , Young D C , Floyd R , Johnson J D
Published: January 2020

The rate of inactivation of poliovirus in water by chlorine is strongly influenced by the pH, which in turn influences the relative amounts of HOCl and OCl- that are present and acting on the virus in the region of pH 6 to 10. The distribution of HOCl and OCl- is influenced to a lesser extent by the addition of NaCl. The major part of the sharp increase in disinfection rate seen with this salt is thought to be due to its effect on the virus itself resulting in an increased chlorine sensitivity, especially at high pH.
Virulence and viability of Yersinia pestis 25 years after lyophilization
Authors: Heckly R J , Blank H
Published: January 2020

When equal volumes of 6% lactose and a broth culture of Yersinia pestis were mixed before freezing, approximately 50% of the cells survived lyophilization and reconstitution on the following day. Concomitantly, the number of viable cells per 50% lethal dose increased from about 16 to 125 organisms. On subsequent storage of the lyophilized cells under vacuum in glass ampoules at 4 degrees C for 25 years, more than 25% of the cells remained viable. When stored cultures were assayed immediately after reconstitution, virulence for mice was significantly reduced (as many as 4,000 cells/50% lethal dose), but the virulence was fully restored when reconstituted cultures were held for 24 h at room temperature, or when a subculture was prepared in fresh medium.
Sediment Distribution of Methanogenic Bacteria in Lake Erie and Cleveland Harbor
Authors: Ward Thomas E. , Frea James I.
Published: January 2020

The direct fluorescent-antibody technique was employed to determine the distribution patterns of four species of methanogens in the sediments of Lake Erie and Cleveland Harbor.
Methanobacterium ruminantium
was the most numerous methanogen found in regions of high-organic-silt sediments. The population of this species ranged from 10
6
to 10
9
cells/g of dry sediment.
Methanobacterium
strain MoH and
Methanosarcina barkeri
were identified in sand-silt, clay, or sand sediments. These methanogens ranged in density from 10
6
to 10
7
cells/g of dry sediment.
Methanospirillum hungatii
was observed only after an organic enrichment was performed on Cleveland Harbor sediments. The seasonal and selective sediment distribution of these methanogens appears to be related to the type and concentration of carbon as substrate as well as to the activities of heterotrophic and sulfate-reducing bacteria.
Effect of pH on the efficiency of growth by pure cultures of rumen bacteria in continuous culture
Authors: Russell J B , Dombrowski D B
Published: January 2020

A total of 10 strains of rumen bacteria, Selenomonas ruminantium HD4, Megasphaera elsdenii B159, Butyrivibrio fibrisolvens A38, Streptococcus bovis JB1, Lactobacillus vitulinus GA1, Bacteroides ruminicola B14, B. ruminicola GA33, Ruminococcus albus 7, Ruminococcus flavefaciens C94, and Bacteroides succinogenes S85, were grown in energy-limiteH of the medium reservoir was lowered approximately 0.3 pH units, and the energy source concentration remaining in the culture vessel, optical density, cell mass, and pH were determined. A low pH appeared to have a detrimental effect on cell yields. Large variations were seen among strains in both the magnitude of yield depressions at lower pH values and in the pH at which the culture washed out. Lactate analysis indicated ta are discussed in relation to the effect of pH on the efficiency of protein synthesis in the rumen and rumen microbial ecology.
Biosynthesis of [14C]zearalenone from [1-14C]acetate by Fusarium roseum 'Gibbosum'
Authors: Hagler W M , Mirocha C J
Published: January 2020

Addition of [1-14C]acetate or [1,2-14C]acetate to actively growing cultures of Fusarium roseum 'Gibbosum' on rice yielded zearalenone with a specific activity ranging between 1.63 and 46.5 microCi/mmol.
Detection of plasmid deoxyribonucleic acid in an isolate of Lactobacillus acidophilus
Authors: Klaenhammer T R , Sutherland S M
Published: January 2020

Eight strains of Lactobacillus acidophilus were examined for the presence of plasmid deoxyribonucleic acid, and one, a pig intestinal isolate, showed the presence of a 13.7- and a 6.3-megadalton plasmid. This is the first reported evidence for plasmid deoxyribonucleic acid in Lactobacillus acidophilus. The functions of these plasmids are presently unknown.
Influence of estuarine sediment on virus survival under field conditions
Authors: LaBelle R L , Gerba C P
Published: January 2020

The survival of poliovirus 1 (LSc) and echovirus 1 (Farouk) in estuarine water and sediment was studied in Galveston Bay, Texas. Viruses were suspended in estuarine water and sediment both in dialysis tubing and in chambers constructed with polycarbonate membrane walls. Virus inactivation rates in seawater were similar in both types of chambers. Virus adsorption to sediment greatly increased survival time. The time required to inactivate 99% (T-99) of poliovirus increased from 1.4 days in seawater alone to 6.0 days for virus adsorbed to sediment at a relatively nonpolluted site. At a more polluted site, poliovirus T-99 was increased from approximately 1 h to 4925 days by virus adsorption to sediment. This study demonstrates that under field conditions virus association with estuarine sediment acts to prolong its survival in the marine environment.
Bacteriological water quality effects of hydraulically dredging contaminated upper Mississippi River bottom sediment
Authors: Grimes D J
Published: January 2020

Bacteriological effects of hydraulically dredging polluted bottom sediment in the navigation channel of the Upper Mississippi River (river mile 827.5 [about 1,332 km] to 828.1 [about 1,333 km]) were investigated. Bottom sediment in the dredging site contained high total coliform densities (about 6,800 most-probable-number total coliform index per g [dry weight] and 3,800 membrane filter total coliforms per g [dry weight]), and fecal coliforms comprised an average 32% of each total coliform count. Total coliform and fecal coliform densities in water samples taken immediately below the dredge discharge pipe were each approximately four times corresponding upstream values; fecal streptococcus densities were approximately 50 times corresponding upstream values. Correlation analysis indicated that mean turbidity values downstream to the dredging operation were directly and significantly (r greater than 0.94) related to corresponding total coliform, fecal coliform, and fecal streptococcus densities. Salmonellae and shigellae were not recovered from either upstream or downstream water samples. Turbidity and indicator bacteria levels had returned to predredge values within less than 2 km below the dredge spoil discharge area at the prevailing current velocity (about 0.15 m/s).
Formation and Purification of
Serratia marcescens
Arylsulfatase
Authors: Murooka Yoshikatsu , Yim Moo-Hyun , Harada Tokuya
Published: January 2020

The effects of culture conditions on arylsulfatase production by six strains of the genus
Serratia
were studied. Synthesis of arylsulfatases in all six strains was repressed in media with inorganic sulfate or methionine as the sole source of sulfur and derepressed by the addition of tyramine.
Serratia marcescens
IFO 3046 grew most rapidly and produced a high level of arylsulfatase when cultured on mannitol with inorganic sulfate and tyramine. The derepressed synthesis of arylsulfatase in
S. marcescens
was not subject to strong catabolite repression. The molecular weight of purified arylsulfatase was determined to be between 46,000 and 49,000. Arylsulfatase from
S. marcescens
differed in
K
m
and
V
max
values, substrate specificities, fluoride inhibition, and electrophoretic mobility from the enzyme from
K. aerogenes
, but had the same molecular weight as the latter.
Microassay for interferon, using [3H]uridine, microculture plates, and a multiple automated sample harvester
Authors: Richmond J Y , Polatnick J , Knudsen R C
Published: January 2020

A microassay for interferon is described which uses target cells grown in microculture wells, [3H]uridine to measure vesicular stomatitis virus replication in target cells, and a multiple automated sample harvester to collect the radioactively labeled viral ribonucleic acid onto glass fiber filter disks. The disks were placed in minivials, and radioactivity was counted in a liquid scintillation spectrophotometer. Interferon activity was calculated as the reciprocal of the highest titer which inhibited the incorporation of [3H]uridine into viral ribonucleic acid by 50%. Interferon titers determined by the microassay were similar to the plaque reduction assay when 100 plaque-forming units of challenge vesicular stomatitis virus was used. However, it was found that the interferon titers decreased approximately 2-fold for each 10-fold increase in the concentration of challenge vesicular stomatitis virus when tested in the range of 10(2) to 10(5) plaque-forming units. Interferon titers determined by the microassay show a high degree of repeatability, and the assay can be used to measure small and large numbers of interferon samples.
Ochratoxin A in blood from slaughter pigs in Sweden: use in evaluation of toxin content of consumed feed
Authors: Hult K , Hökby E , Gatenbeck S , Rutqvist L
Published: January 2020

Samples of pig blood, intended for ochratoxin A analysis, were collected from pigs of 279 randomly selected herds. The samples were obtained at nine different slaughterhouses from different areas of Sweden. Pigs from 47 herds (16.8% of the total) exhibited ochratoxin A in amounts of greater than or equal to 2 ng of ochratoxin A per ml of blood. One sample each from a single pig per herd identified herds contaminated with ochratoxin A in amounts exceeding three times the detection limit of the method (3 x 2 ng of ochratoxin A per ml of blood = 6 ng of ochratoxin A per ml of blood). There was a good agreement between ochratoxin A concentrations in the blood from different pigs within the same herd (correlation coefficient = 0.80). The ochratoxin A concentration in pig blood was used as an estimate of the ochratoxin A content of the consumed feed. This method showed that feed from grain produced on-farm contained higher concentrations of ochratoxin A than commercial feed preparations. No geographical variation of ochratoxin A occurrence within Sweden was detected.
Method for recovering viruses from river water solids
Authors: Berg G , Dahling D R
Published: January 2020

Small numbers of virions (poliovirus 1) that had been adsorbed to river water solids were eluted by mixing the solids for 30 min with a 10% solution of beef extract that contained sufficient Na2HPO4 to bring the molarity of the salt to 0.05 and sufficient citric acid to bring the pH to 7. The virions were recovered by inoculating the beef extract onto cell cultures. With this method, 39 to 63% of the poliovirions that had been adsorbed onto the river water solids were recovered.
Tracer Analysis of Methanogenesis in Salt Marsh Soils
Authors: King Gary M. , Wiebe W. J.
Published: January 2020

Differences in paths of carbon flow have been found in soils of the tall (TS) and short (SS)
Spartina alterniflora
marshes of Sapelo Island, Ga. Gaseous end products of [
U
-
14
C]glucose metabolism were
14
CO
2
and
14
CH
4
in the SS region and primarily
14
CO
2
in the TS region. Sulfate concentration did not demonstrably affect glucose catabolism or the distribution of end products in either zone. [
U
-
14
C]acetate was converted to
14
CO
2
and
14
CH
4
in the SS soils and almost exclusively to
14
CO
2
in the TS soils. Sulfate concentration did not affect acetate metabolism in the SS soils; however, a noticeable effect of sulfate dilution was seen in TS soils. Sulfate dilution in TS samples resulted in increased methane formation. Total glucose and acetate metabolism were similar in TS and SS soils despite differences in end products. A microbial community characterized by fermentative/sulfate-reducing processes has developed in TS soils as opposed to the fermentative/methanogenic/sulfate-reducing community found in SS soils.
Microbial Colonization and Decomposition of
Carex
Litter in an Arctic Lake
Authors: Federle Thomas W. , Vestal J. Robie
Published: January 2020

The decomposition and microbial colonization of
Carex
leaf litter were examined in an arctic lake in Alaska during the summer of 1978. Dried leaf segments in screen bags were placed at various locations and depths for 13 and 26 days. Weight loss varied from 24.15 to 33.56% and from 27.69 to 65.01% after 13 and 26 days, respectively. Abiotic controls lost approximately 19.5% with no subsequent change. Weight loss significantly correlated with microbial colonization as measured by alkaline phosphatase activity (
r
= 0.780), cellulase activity (
r
= 0.613), heterotrophic CO
2
fixation (
r
= 0.835), and acetate incorporation into microbial lipids (
r
= 0.618). Alkaline phosphatase activity correlated with cellulase activity (
r
= 0.889), and heterotrophic CO
2
fixation correlated with acetate incorporation into lipids (
r
= 0.712). Weight loss after 26 days inversely correlated with the logarithm of the depth of incubation regardless of whether incubation occurred on the sediment surface or in the water column. These findings suggest that a rapid initial period of microbial colonization is driven by nutrients derived from the litter and that the rate of these processes is controlled by a factor(s) inversely related to the logarithm of depth, such as light intensity, primary production, or turbulence.
Polyacrylamide Slab Gel Electrophoresis of Soluble Proteins for Studies of Bacterial Floras
Authors: Moore W. E. C. , Hash D. E. , Holdeman Lillian V. , Cato Elizabeth P.
Published: January 2020

A polyacrylamide slab gel electrophoresis procedure was used to compare cellular proteins from bacterial isolates of gingival crevice floras. Isolates with identical protein patterns consistently were shown to be members of the same species. When used to screen isolates, the procedure reduced total analytical time and expense without sacrificing accuracy, and it provided additional verification of the identity of strains characterized by conventional phenotypic tests.
Improved Medium for Detection of Citrate-Fermenting
Streptococcus lactis
subsp.
diacetylactis
Authors: Kempler G. M. , McKay L. L.
Published: January 2020

A modified medium which distinguished between citrate-fermenting and non-citrate-fermenting species of lactic streptococci within 48 h was developed. In addition, the occurrence of citrate-negative variants in citrate-positive populations of
Streptococcus lactis
subsp.
diacetylactis
could be detected.
High Cellobiase and Xylanase Production by
Sclerotium rolfsii
UV-8 Mutant in Submerged Culture
Authors: Sadana J. C. , Shewale J. G. , Deshpande M. V.
Published: January 2020

Sclerotium rolfsii
UV-8 mutant secretes high levels of cellobiase and xylanase in addition to having high cellulase production. The apparent
K
m
and
V
max
of cellobiase (grown in NM-2 + 2% corn steep liquor medium) with cellobiose as a substrate were 5.6 mM and 22.2 μmol of glucose liberated per min per ml of culture filtrate, respectively. The addition of 2% corn steep liquor to NM-2 medium increased endo-β-glucanase, cellobiase, and xylanase yields by approximately 1.5-fold.
Isolation, Enumeration, and Characterization of
Aeromonas
from Polluted Waters Encountered in Diving Operations
Authors: Seidler Ramon J. , Allen D. A. , Lockman H. , Colwell R. R. , Joseph S. W. , Daily O. P.
Published: January 2020

Counts of total viable, aerobic, heterotrophic bacteria, indicator organisms, and
Aeromonas
spp. were made at a diver training site on the Anacostia River in Washington, D.C. The numbers of
Aeromonas
cells in Anacostia River sediment and water increased during periods of elevated water temperature, to maxima of 4 � 10
5
cells per g of sediment and 300 cells per ml of water. Correspondingly,
Aeromonas
counts dropped 2 to 4 logs as the water temperature decreased to 0 to 0.5�C. Cultures taken by sterile swabs from the ears and face masks of divers after a 30-min swim in the Anacostia River yielded bacterial types and numbers similar to those found in the river. The nasal passages of the divers apparently did not become contaminated by swimming, possibly because of the protective effect of the face masks used by the divers. Properties associated with virulence in
Aeromonas hydrophila
and
Aeromonas sobria
strains isolated from the river, sediment, and divers were investigated. Nearly 40% of the strains of both species collected during the study produced cytotoxic activity for mouse Y-1 adrenal cells, as well as elastase. Enterotoxin activity, as detected by the Y-1 assay, was observed in 3% (1 of 35) of the strains of
A. sobria
and in 6% (19 of 330) of the
A. hydrophila
strains. Fluid accumulation in rabbit ileal loops induced by both species of
Aeromonas
varied greatly among the 17 strains examined. Fluid accumulation of at least 0.4 ml/cm was correlated with positive cytotoxin- or enterotoxin-like response in the Y-1 tissue culture assay.
Enumeration and Relative Importance of Acetylene-Reducing (Nitrogen-Fixing) Bacteria in a Delaware Salt Marsh
Authors: Dicker Howard J. , Smith David W.
Published: January 2020

Three groups of N
2
-fixing bacteria were enumerated from the top 1 cm of the surface in four vegetational areas in a Delaware salt marsh. The results over the 9-month sampling period showed that there were no discernible seasonal patterns for any of the groups enumerated (
Azotobacter
sp.,
Clostridium
sp., and
Desulfovibrio
sp.).
Azotobacter
sp. was present in numbers of 10
7
per g of dry mud, whereas the two anaerobic fixers were present in much lower numbers (10
3
to 10
4
per g of dry mud). There were no differences in the numbers of each group among the different vegetational areas, indicating that there was a heterogeneous population of N
2
fixers present. Additional studies indicate that the activity of sulfate reducers (
Desulfovibrio
sp.) may account for as much as 50% of the total observed acetylene reduction activity. Oxygen was found to exert little effect on the observed acetylene reduction activity, indicating that stable aerobic and anaerobic microenvironments exist in the surface layer of marsh sediments.
Effect of zearalenone on female White Leghorn chickens
Authors: Chi M S , Mirocha C J , Weaver G A , Kurtz H J
Published: January 2020

Acute toxic effects of purified zearalenone were studied in growing female White Leghorn chickens. In the first experiment, zearalenone in gelatin capsules was administered to 10 chickens (zearalenone-treated chickens [ZC]) in a single oral dose of 15.0 g/kg. Another 10 control chickens (CC) received empty gelatin capsules. All chickens survived the 10-day experiment and did not show any noticeable gross or histopathological lesions. There were no differences between CC and ZC in weight gain, oviduct, comb and liver weights, hematological parameters, and serum cholesterol. ZC had significantly less (P less than 0.05) serum calcium but significantly greater (P less than 0.01) serum phosphorus than CC. In the second experiment, zearalenone was administered orally or intramuscularly (pectoral muscle) at levels of 0, 50, 200, 400, and 800 mg/kg for 7 consecutive days. The oviduct weight increased with increasing toxin levels in both orally (OZC) and intramuscularly (IZC) administered groups: there were more pronounced effects in the IZC. The liver weight increased and comb weight decreased in IZC. The relative estrogenic biopotency of zearalenone in IZC, using estradiol dipropionate as a standard, was 1.37%. The results of this experiment demonstrate that chickens are highly tolerant to zearalenone and that the estrogenic effects of the toxin are greater when it is administered in multiple doses than in a single dose and in IZC than in OZC.
Separation of
d
-(+)-Nicotine from a Racemic Mixture by Stereospecific Degradation of the
l
-(−) Isomer with
Pseudomonas putida
Authors: DeTraglia Michael C. , Tometsko Andrew M.
Published: January 2020

Incubation of racemic mixtures of
dl
-(�)-nicotine with
Pseudomonas putida
resulted in a complete stereoselective degradation of the
l
-(−) isomer. Unnatural
d
-(+)-nicotine, which is of pharmacological interest for stereochemical studies of various nicotine-responsive systems, was not affected by the bacterium and was recovered by extraction.
Simple method for demonstrating small plasmid deoxyribonucleic acid molecules in oral streptococci
Authors: Macrina F L , Wood P H , Jones K R
Published: January 2020

A simple procedure for rapidly demonstrating small plasmids (less than 10 megadaltons) in oral streptococci is described. Logarithmic-phase, glycine-treated cells from 1.5-ml broth cultures were converted to osmotically fragile forms and lysed with sodium dodecyl sulfate. After the hydrodynamic shearing of host chromosomal deoxyribonucleic acid, such lysates were analyzed by low-voltage agarose gel electrophoresis. Small plasmids, migrating significantly faster than chromosomal deoxyribonucleic acid under such conditions, were readily visualized by ethidium bromide staining.
Comparative study on the mechanisms of rotavirus inactivation by sodium dodecyl sulfate and ethylenediaminetetraacetate
Authors: Ward R L , Ashley C S
Published: January 2020

This report describes a comparative study on the effects of the anionic detergent sodium dodecyl sulfate and the chelating agent ethylenediaminetetraacetate on purified rotavirus SA-11 particles. Both chemicals readily inactivated rotavirus at quite low concentrations and under very mild conditions. In addition, both agents modified the viral capsid and prevented the adsorption of inactivated virions to cells. Capsid damage by ethylenediaminetetraacetate caused a shift in the densities of rotavirions from about 1.35 to about 1.37 g/ml and a reduction in their sedimentation coefficients. Sodium dodecyl sulfate, on the other hand, did not detectably alter either of these physical properties of rotavirions. Both agents caused some alteration of the isoelectric points of the virions. Finally, analysis of rotavirus proteins showed that ethylenediaminetetraacetate caused the loss of two protein peaks from the electrophoretic pattern of virions but sodium dodecyl sulfate caused the loss of only one of these same protein peaks.
Utilization of Dichloromethane by Suspended and Fixed-Film Bacteria
Authors: Rittmann Bruce E. , McCarty Perry L.
Published: January 2020

Dichloromethane (methylene chloride) was biodegraded by and supported growth of suspended and fixed-film bacteria enriched from sewage.
Comparison of direct serial dilution and most-probable-number methods for determining endotoxins in meats by the Limulus amoebocyte lysate test
Authors: Seiter J A , Jay J M
Published: January 2020

When the endotoxin content of ground beef was determined by direct serial dilution and by three-tube most-probable-number methods, the results were not significantly different, although the latter method provided more specific values for individual samples.
Purification of glycoside hydrolases from Bacteroides fragilis
Authors: Berg J O , Lindqvist L , Nord C E
Published: January 2020

Six glycoside hydrolases in the culture medium of Bacteroides fragilis--alpha-glucosidase, beta-glucosidase, alpha-galactosidase, beta-galactosidase, beta-N-acetylglucosaminidase, and alpha-L-fucosidase-were systematically purified by ammonium sulfate precipitation, gel filtration chromatography, and density gradient isoelectric focusing. The isoelectric focusing resolved the glycosidases into distinct, well-separated fractions and revealed three differently charged forms of beta-N-acetylglucosaminidase and of alpha-L-fucosidase. Furthermore, alpha-glucosidase and beta-N-acetylglucosaminidase were shown to possess dual affinities for the respective galactoside substrates, and beta-galactosidase also hydrolyzed beta-D-fucoside. alpha-Glucosidase was purified to homogeneity, as indicated by a thin-layer isoelectric focusing zymogram technique. The glycosidases, with exception of beta-glucosidase and the acid alpha-L-fucosidase, were each separated from other glycosidic activities to 99%. The molecular weights varied between 58,000 and 125,000. The pH optima ranged from 4.8 to 6.9.