bluuebunny/crossref_metadata_2025 huggingface dataset:
Growth of Pseudomonas aeruginosa in tap water in relation to utilization of substrates at concentrations of a few micrograms per liter
Authors: van der Kooij D , Oranje J P , Hijnen W A
Published: January 2020

Five Pseudomonas aeruginosa strains were tested for the utilization of 47 low-molecular-weight compounds as their sole sources of carbon and energy for growth at a concentration of 2.5 g/liter. Of these compounds, 31 to 35 were consumed. Growth experiments in tap water at 15 degrees C were carried out with one particular strain (P1525) isolated from drinking water. This strain was tested for the utilization of 30 compounds supplied at a concentration of 25 microgram of C per liter. The growth rate (number of generations per hour) of strain P1525 in this tap water was approximately 0.005 h-1, and with 10 compounds it was larger than 0.03 h-1. An average yield of 6.2 x 10(9) colony-forming units per mg of C was obtained from the maximum colony counts (colony-forming units per milliliter). The average yield and maximum colony count of strain P1525 grown in tap water supplied with a mixture of 45 compounds, each at a concentration of 1 microgram of C per liter, enabled us to calculate that 28 compounds were utilized. Growth rates of two P. aeruginosa strains (including P1525) in various types of water at 15 degrees C were half of those of a fluorescent pseudomonad. The concentrations of assimilable organic carbon calculated from maximum colony counts and average yield values amounted to 0.1 to 0.7% of the total organic carbon concentrations in five types of tap water. The assimilable organic carbon percentages were about 10 times larger in river water and in water after ozonation.
Extraction of Clostridium perfringens spores from bottom sediment samples
Authors: Emerson D J , Cabelli V J
Published: January 2020

Two extraction-separation procedures were developed and evaluated for use in conjunction with the mCP membrane filter method for the enumeration of Clostridium perfringens spores in bottom sediments. In the more facile of the two procedures, a distilled-water suspension of the sediment sample is pulse sonicated for 10 s and allowed to settle. Portions of the supernatant are then removed for membrane filtration. This procedure is recommended for general use. The more complicated procedure is recommended for situations in which the presence of high levels of toxic materials is suspected or in which relatively low spore densities are present in fine silts. In this procedure, sonication is followed by a distilled water wash. The centrifuged sediment is resuspended in distilled water and mixed with the components of a two-phase separation system (50% polyethylene glycol in distilled water and 25% sucrose in 3 M phosphate buffer [pH 7.1]). After equilibration of the system and low-speed centrifugation, the top phase and interphase are removed, mixed, and membrane filtered. The recoveries of C. perfringens spores by the two procedures, when used in conjunction with the mCP method, were comparable to each other and significantly greater than those by the British most-probable-number method. It was estimated that more than 85% of the spores were recovered by the procedures. The precision of the sonicate-and-settle-mCP procedure was markedly better than that obtained theoretically by the most-probable-number method and approached that theoretically attributable to counting an average of 85 colonies on each of two plates.
High-temperature tenderizing of beef sides: bacterial considerations
Authors: Wilhelm K E , Marsh B B , Lochner J V
Published: January 2020

A microbiological study of an experimental beef-tenderizing treatment, in which lean sides are held at 37 degrees C until transfer to a chiller at 3 h postmortem, was made. The treatment did not cause a significant increase in bacterial numbers or a proliferation of potential pathogens or food-spoiling organisms.
Elimination of plasmid-linked polyglutamate production by Bacillus subtilis (natto) with acridine orange
Authors: Hara T , Aumayr A , Fujio Y , Ueda S
Published: January 2020

Treatment of Bacillus subtilis (natto) strains Asahikawa, F, and M with acridine orange resulted in the conversion of approximately 64.2% of the Asahikawa population, 22.4% of the F population, and 9.2% of the M population to polyglutamate-nonproducing colonies. Such curing is suggestive of the involvement of plasmid DNA. Samples of cleared lysates of both parental and their cured strains were subjected to agarose gel electrophoresis to determine the plasmid composition. Parental strains were found to possess a plasmid, but polyglutamate-nonproducing derivatives were missing the plasmid. The plasmid-linked polyglutamate production, which was originally isolated from B. subtilis (natto), could be transformed in B. subtilis.
Fungal Transformations of Triparanol
Authors: Warner Steven A. , Sovocool G. Wayne , Domnas Aristotle J.
Published: January 2020

Fungal transformations of triparanol, a hypercholesterolemic drug, were studied in
Lagenidium giganteum
and
Lagenidium callinectes.
The products were identified by combined gas chromatography-mass spectrometry. Two metabolites were observed from each organism; only one of the metabolites was found in both organisms.
Breakdown of Diazotized Proteins and Synthetic Substrates by Rumen Bacterial Proteases
Authors: Wallace R. John , Kopecny Jan
Published: January 2020

Several different kinds of substrate were used to investigate the proteolytic activity of rumen bacteria and of proteases released from rumen bacteria by blending (“coat proteases”). These substrates included diazotized feed proteins and diazotized soluble and insoluble pure proteins. It was concluded that, while solubility was an important factor, the secondary and tertiary structure of a protein had a major influence on its rate of digestion. The resistance of elastin congo red to digestion indicated that similar fibrous proteins in plant material might resist proteolytic attack by rumen bacteria. Coat proteases had a broad specificity, including several exo- and endopeptidase activities, as determined by using synthetic peptide substrates.
Azo Dye Colony Staining Technique To Detect Fungal Mutants Lacking β-Glucosidase Activity
Authors: Rissler Jane F.
Published: January 2020

A simple, rapid, convenient, easily interpreted azo dye colony-staining technique was developed to detect fungal mutants lacking β-glucosidase activity on a 6-bromo-2-naphthyl substrate. The procedure includes net replication of colonies and chemical restriction of colony growth to allow testing of many colonies per culture dish.
Production of Rosamicin: Improvement of Synthetic Medium
Authors: Kwak J. W. , Kim K. S. , Ryu Dewey D. Y.
Published: January 2020

Rosamicin is one of the important macrolide antibiotics that has clinical efficacy and broad-spectrum antibacterial activity. Using a mutant strain of
Micromonospora rosaria
(NRRL 3718), a chemically defined medium was developed, and some fermentation conditions that are important to rosamicin biosynthesis were optimized to achieve rosamicin productivity of 230 μg/ml. Soluble starch and
l
-asparagine were found to be the best carbon and nitrogen sources, and a stimulative effect of magnesium and zinc ions was also found. The medium developed contains: soluble starch, 4%;
l
-asparagine, 0.15%; K
2
HPO
4
, 0.075%; CaCO
3
, 0.6%; MgSO
4
· 7H
2
O, 0.05%; FeSO
4
· 7H
2
O, 10
−4
M; CuSO
4
· 5H
2
O, 10
−5
M; ZnSO
4
· 7H
2
O, 10
−5
M; and MnSO
4
· (4-6)H
2
O, 10
−6
M. The required air supply was about 40 mmol of O
2
liter
−1
· h
−1
· atm
−1
, and the favorable culture temperature was 28 to 29°C.
Responses of Marine Bacteria Under Starvation Conditions at a Solid-Water Interface
Authors: Humphrey Beverley , Kjelleberg Staffan , Marshall Kevin C.
Published: January 2020

Size changes during starvation of 17 marine bacterial isolates at a solid-water interface and in the liquid phase were examined. Twelve rod-shaped, hydrophilic bacteria decreased in size more rapidly at the solid surface than in the liquid phase, a result parallel to that observed previously for one of the strains at an air-water interface. On the other hand, three rod-shaped, hydrophobic bacteria diminished in size more rapidly in the liquid phase than at the solid-water interface. The rapid size decrease (defined here as the dwarfing phase) in either situation appeared to be an active process which occurred more rapidly when the cells were in an early stage of logarithmic growth at the onset of starvation. Dwarfing was reversibly inhibited by low temperature and low pH but was not inhibited by chloramphenicol. Three coccoidal bacteria showed little tendency to become smaller upon starvation in the liquid phase or at a surface.
Automatic diluter for bacteriological samples
Authors: Trinel P A , Bleuze P , Leroy G , Moschetto Y , Leclerc H
Published: January 2020

The described apparatus, carrying 190 tubes, allows automatic and aseptic dilution of liquid or suspended-solid samples. Serial 10-fold dilutions are programmable from 10(-1) to 10(-9) and are carried out in glass tubes with screw caps and split silicone septa. Dilution assays performed with strains of Escherichia coli and Bacillus stearothermophilus permitted efficient conditions for sterilization of the needle to be defined and showed that the automatic dilutions were as accurate and as reproducible as the most rigorous conventional dilutions.
Production and Consumption of Hydrogen in a Eutrophic Lake
Authors: Conrad Ralf , Aragno Michel , Seiler Wolfgang
Published: January 2020

The vertical distribution of hydrogen was measured in the Loclat, a eutrophic and holomictic lake near Neuchâtel, Switzerland, before and during summer stratification. H
2
concentrations decreased with depth in the anaerobic hypolimnion and were often below the detection limit (2.5 nl of H
2
liter
−1
) in the water adjacent to the lake sediment. H
2
was apparently not released from the lake sediment. The highest H
2
concentrations (>4 μl of H
2
liter
−1
) were observed in the aerobic water of the epilimnion and metalimnion. There, the H
2
concentrations changed with time, indicating a turnover of H
2
. The H
2
production processes could not be studied in the laboratory since incubation of water samples in light or darkness did not result in H
2
production but rather always in H
2
consumption. The possible role of cyanobacteria and algae for H
2
production is discussed. Aerobic or anaerobic H
2
consumption activities were observed at all depths of the water column, with highest activities in the hypolimnion. Aerobic H
2
consumption activity was insensitive to azide inhibition, but sensitive to heat, mercuric chloride, or cyanide. It was restricted to a particle fraction of 0.2 to 3.0 μm in size, so that it must be due to single bacterial cells. Aerobic hydrogen bacteria, on the other hand, occurred in clusters of >3.0 μm. Therefore, the hydrogen bacteria could not have caused the H
2
consumption in lake water. The aerobic H
2
consumption activity followed Michaelis-Menten kinetics, with a
K

m

of 67 nM H
2
. This is an exceptionally low value compared with
K

m

values of hydrogenases in hydrogen bacteria and other species, but is similar to that for H
2
-decomposing abiontic soil hydrogenases.
Legionella oakridgensis: unusual new species isolated from cooling tower water
Authors: Orrison L H , Cherry W B , Tyndall R L , Fliermans C B , Gough S B , Lambert M A , McDougal L K , Bibb W F , Brenner D J
Published: January 2020

We describe a new species of Legionella represented by 10 strains isolated from industrial cooling towers. Legionella oakridgensis differed genetically from the other seven species of Legionella in DNA hybridization studies and differed serologically in direct fluorescent-antibody tests. The new species, unlike all other species except L. jordanis, did not require added L-cysteine for growth in serial transfer on charcoal-yeast extract agar. L. oakridgensis, as well as three other species tested, required L-cysteine for primary isolation from animal tissues. L. oakridgensis was the only species of Legionella that failed to produce alkaline phosphatase at pH 8.5. In all other respects, it resembled other species of Legionella, including having a high content of branched-chain cellular fatty acids and being pathogenic for guinea pigs. These bacteria have not yet been associated with human disease, but they are potential causes of legionellosis.
Bacteriological quality of fabrics washed at lower-than-standard temperatures in a hospital laundry facility
Authors: Christian R R , Manchester J T , Mellor M T
Published: January 2020

We determined whether the bacteriological quality of fabrics cleaned in a hospital laundry could be maintained at wash temperatures lower than 75 degrees C by the use of economically reasonable formulas and wash conditions. Three groups of bacteria were examined to determine bacteriological quality: aerobic, nonexacting chemoorganotrophs, staphylococci, and total coliforms. The distribution of bacteria on soiled fabric was patchy, with staphylococci and total coliforms ranging from less than 0.1 to greater than 4 X 10(3) CFU/cm2 and chemoorganotrophs ranging from less than 0.1 to greater than 5 X 10(5) CFU/cm2. The washing process routinely produced fabric containing less than 1 CFU/cm2. Low-temperature (47.8 to 60.0 degrees C) wash procedures eliminated all bacterial groups at least as effectively as did high-temperature procedures. The effectiveness of bacterial density reduction at low temperature was augmented by increased concentrations of bleach. Successful low-temperature washing such as that shown here may save both energy and money for hospitals.
Effects of Iron Starvation on the Ultrastructure of the Cyanobacterium
Agmenellum quadruplicatum
Authors: Hardie L. P. , Balkwill D. L. , Stevens S. E.
Published: January 2020

The effects of iron starvation on the ultrastructure of the unicellular cyanobacterium
Agmenellum quadruplicatum
were studied by using thin sectioning and transmission electron microscopy. Intracellular polysaccharide began to accumulate at the onset of iron limitation. This was followed by degradation of ribosomes and (later) degradation of the thylakoid membranes, both of which were virtually absent by 200 h. The thylakoids underwent structural modifications and rearrangements before they actually began to break down. Iron starvation did not appear to affect carboxysomes or the extracellular glyocalyx. On the other hand, polyphosphate bodies may have been partially degraded, and an electrontransparent gap eventually appeared between the cell wall and the cytoplasmic membrane. All of these changes were reversed when iron was added back to 200-h starved cultures. The sequence of ultrastructural changes observed during iron starvation clearly differed from those previously reported to occur during nitrogen, phosphorous, or carbon limitation.
Starvation-Survival Patterns of Sixteen Freshly Isolated Open-Ocean Bacteria
Authors: Amy Penny S. , Morita Richard Y.
Published: January 2020

Sixteen marine isolates from a NORPAX cruise, which were transferred once on medium after initial isolation, survived nutrient deprivation for at least 8 months (longest period test). All but one isolate remained cellularly intact, although their sizes and shapes changed greatly, and all became smaller, decreasing in size from 40 to 79%. Three starvation-survival patterns were demonstrated, namely (i) an initial increase in viable cells followed by a decrease until a constant number was reached, (ii) an increase in viable cells until a constant number was reached, and (iii) a decrease in viable cells until a constant number was reached. One isolate from each starvation-survival pattern was starved for 8 months and then was tested in comparison with 4-month-starved Ant-300 for [
14
C]glutamic acid uptake, respiration, and incorporation. The response to glutamic acid was rapid and linear in each case. The data indicate that the starvation-survival of Ant-300 is not an anomalous situation and that open ocean bacteria can withstand nutrient deprivation for long periods of time and still retain the capacity for active metabolism, if the nutrients become available.
Identification of
Rhizobium phaseoli
Strains That Are Tolerant or Sensitive to Soil Acidity
Authors: Lowendorf Henry S. , Alexander Martin
Published: January 2020

A study was conducted to determine whether the survival of
Rhizobium phaseoli
in acid soils could be predicted on the basis of the tolerance of the organism to acidity in culture. Of 16 strains tested, all grew in culture at pH 4.6, but only those that grew at pH 3.8 survived in soils having pH values of 4.1 to 4.6. Strains that tolerated the lowest pH values in culture were tolerant of the highest aluminum concentrations. In one acid soil, an acid-tolerant strain was unable to survive in numbers greater than 100/g, but the poor survival was not related to the level of extractable aluminum or manganese in the soil. Reproduction of an acid-tolerant strain of
R. phaseoli
was enhanced in the rhizosphere of
Phaseolus vulgaris
in both acid and limed soils, but stimulation of an acid-sensitive strain by the plant occurred only in the limed soil. These results indicate that cultural tests can be used to predict the ability of
R. phaseoli
to survive in acid soil.
Bioassay and dose measurement in UV disinfection
Authors: Qualls R G , Johnson J D
Published: January 2020

A bioassay method was developed to measure the average intensity within a UV disinfection reactor. The survival of spores of Bacillus subtilis was determined as a function of UV dose to prepare a standard curve. Spores were added to unknown systems, and the survival rate was used to determine the average intensity. A modification was used for flow-through reactors by which spores were injected as a spike and collected at a known time after injection. A point source summation method for calculating intensity was verified by bioassay measurements in a simple cylinder. This calculation method was also applied to multiple-lamp reactors.
Rapid Colony Screening Method for Identifying Hydrogenase Activity in
Rhizobium japonicum
Authors: Haugland Richard A. , Hanus Frank J. , Cantrell Michael A. , Evans Harold J.
Published: January 2020

A method has been developed for the rapid screening of
Rhizobium japonicum
colonies for hydrogenase activity based on their ability to reduce methylene blue in the presence of respiratory inhibitors and hydrogen. Hydrogen uptake-positive (Hup
+
) colonies derepressed for hydrogenase activity were visualized by their localized decolorization of filter paper disks impregnated with the dye. Appropriate responses were seen with a number of Hup
+
and Hup
−
wild-type strains of
R. japonicum
as well as Hup
−
mutants. Its specificity was further confirmed in selected strains on the basis of comparisons with chemolithotrophic growth and the presence of other genetic markers. Utilization of the method in identifying Hup
+
colonies among 16,000 merodiploid derivatives of the Hup
−
mutant strain PJ17nal containing cloned DNA fragments of the Hup
+
strain 122 DES has demonstrated its applicability as a screening procedure in the genetic analysis of the
R. japonicum
hydrogen uptake system.
Distribution of
Vibrio vulnificus
and Other Lactose-Fermenting Vibrios in the Marine Environment
Authors: Oliver James D. , Warner Robert A. , Cleland David R.
Published: January 2020

During the summer of 1981, 3,887 sucrose-negative vibrios were isolated from seawater, sediment, plankton, and animal samples taken from 80 sites from Miami, Fla., to Portland, Maine. Of these, 4.2% were able to ferment lactose. The lactose-positive strains isolated from the various samples correlated positively with pH and turbidity of the water, vibrios in the sediment and oysters, and total bacterial counts in oysters. Negative correlations were obtained for water salinity. Numerical taxonomy was performed on 95 of the lactose-fermenting environmental isolates and 23 reference strains. Five clusters resulted, with the major cluster containing 33 of the environmental isolates and all of the
Vibrio vulnificus
reference strains. The 33 isolates, which produced an acid reaction in lactose broth within hours of initial inoculation, represented 20% of all lactose-fermenting vibrios studied. These isolates were nearly identical phenotypically to clinical strains of
V. vulnificus
studied by the Centers for Disease Control, Atlanta, Ga., and by our laboratory, and their identification was confirmed by DNA-DNA hybridization studies.
V. vulnificus
was isolated from all sample types and from Miami to Cape Cod, Mass., and comparison of the environmental parameters of the eight subsites yielding this species with those of all 80 subsites revealed no significant differences. The majority of the isolates were obtained from animals, with clams providing most (84%) of these. On injection into mice, 82% of the
V. vulnificus
isolates resulted in death. Members of the remaining four clusters contained strains which differed from
V. vulnificus
in such phenotypic traits as luminescence and in urease or H
2
S production. None of the other reference cultures, including nine other
Vibrio
species, were contained in the remaining clusters, and these isolates could not be identified. Most of these were also lethal for mice. Phenotypic differences, potential pathogenicity, and geographic distribution of the five clusters were examined. It is concluded that
V. vulnificus
is a ubiquitous organism, both geographically and in a variety of environmental sources, although it occurs in relatively low numbers. The public health significance of this organism and of the other unidentified lactose-fermenting
Vibrio
species is discussed.
Methods for Mutation and Selection of the Ergot Fungus
Authors: Srikrai Suthinee , Robbers James E.
Published: January 2020

A new method is described in which the Salkowski reaction is used for the rapid selection of alkaloid-producing mutants of the ergot fungus. This method was used to investigate the influence of a second mutation with
N
-methyl-
N
′-nitro-
N
-nitrosoguanidine (NTG) on various mutants selected by a preliminary NTG mutation of
Claviceps
sp. strain SD 58. Three groups of mutants were used: high alkaloid producers, low alkaloid producers, and auxotrophs. Results indicated that a second mutation of all three types of mutants could improve alkaloid yield and vegetative vigor. In addition, a second mutation increased the frequency of auxotroph production. The difficulty of producing stable mutants from ergot strains that have multinucleated cells and that do not readily produce conidia in culture, such as an ergotamine-producing strain, was overcome by first forming protoplasts of the fungus and then subjecting them to the mutagen. Stable auxotrophs were obtained in this manner.
Adaptation of mesophilic anaerobic sewage fermentor populations to thermophilic temperatures
Authors: Chen M
Published: January 2020

Thermophilic (50 degrees C) and obligately thermophilic (60 degrees C) anaerobic carbohydrate- and protein-digesting and methanogenic bacterial populations were enumerated in a mesophilic (35 degrees C) fermentor anaerobically digesting municipal primary sludge. Of the total bacterial population in the mesophilic fementor, 9% were thermophiles (36 x 10(6)/ml) and 1% were obligate thermophiles (4.5 x 10(6)/ml). Of these 10%, the percentages of bacteria (thermophiles and obligate thermophiles, respectively) able to use specific substrates were further enumerated as follows: bacteria able to digest albumin, casein, starch, and mono- and disaccharides, 30 and 10%; pectin degraders, 10 and 0.2%; cellulose degraders, 2 and 0.06%; methanogens that grow with H2 and CO2, methanol, and dimethylamine, 9 and 1%; methanogens that grow with formate, 8 and 5%; and methanogens that grow with acetate, 25 and less than 0.8%. Shortly after the temperature was elevated from 35 to 50 or 60 degrees C, the digestion of albumin, casein, starch, and mono- and disaccharides was detected, and methane was produced from H2 and CO2. Methane produced from acetate was not delayed at 50 degrees C, but was delayed by 29 days at 60 degrees C. Methane produced from formate was delayed by 3 days, from methanol by 7 days, and from dimethylamine by 5 days at 50 and 60 degrees C. A 10- and 20-day acclimation period was required for hydrolysis of pectin and cellulose, respectively, at 50 degrees C. Digestion of pectin required 20 days and cellulose longer than 85 days when the temperature was elevated abruptly from 35 to 60 degrees C. The acclimation period for the digestion of pectin and cellulose at 60 degrees C was shortened to 3 and 15 days, respectively, by seeding with a small amount of a culture acclimated to 50 degrees C. The data suggest that enrichment of cellulolytic, pectinolytic, and acetate-utilizing bacteria is crucial for the digestion of sewage sludge at 60 degrees C.
Application of a competition model to the growth of Streptococcus mutans and Streptococcus sanguis in binary continuous culture
Authors: Kemp C W , Robrish S A , Curtis M A , Sharer S A , Bowen W H
Published: January 2020

Streptococcus mutans 6715-15 and Streptococcus sanguis 10558 were grown together in continuous culture with glucose as the limiting carbon source. The relationship of growth rate to substrate concentration was determined for pure cultures of each organism in continuous and batch cultures. A model based on competition for a growth-limiting substrate (glucose) was used to predict the proportions of each organism when grown in binary cultures. The results indicate that interactions other than competition for glucose carbon exist between S. mutans and S. sanguis grown under these conditions.
Regulation of Expression of Nitrate and Dinitrogen Assimilation by
Anabaena
Species
Authors: Meeks John C. , Wycoff Keith L. , Chapman John S. , Enderlin Carol S.
Published: January 2020

Anabaena
sp. strain 7120 appeared more responsive to nitrogen control than
A. cylindrica.
Growth in the presence of nitrate strongly repressed the differentiation of heterocysts and fixation of dinitrogen in
Anabaena
sp. strain 7120, but only weakly in
A. cylindrica.
Nitrate assimilation by ammonium-grown cultures was strongly repressed in
Anabaena
sp. strain 7120, but less so in
A. cylindrica.
The repressive effect of nitrate on dinitrogen assimilation in
Anabaena
sp. strain 7120, compared to
A. cylindrica
, did not correlate with a greater rate of nitrate transport, reduction to ammonium, assimilation into amino acids, or growth. Although both species grew at similar rates with dinitrogen,
A. cylindrica
grew faster with nitrate, incorporated more
13
NO
3
−
into amino acids, and assimilated (transported) nitrate at the same rate as
Anabaena
sp. strain 7120. Full expression of nitrate assimilation in the two species occurred within 2.5 h (10 to 14% of their generation times) after transfer to nitrate medium. The induction and continued expression of nitrate assimilation was dependent on protein synthesis. The half-saturation constants for nitrate assimilation and for nitrate and ammonium repression of dinitrogen assimilation have ecological significance with respect to nitrogen-dependent growth and competitiveness of the two
Anabaena
species.
Ensifer adhaerens
Predatory Activity Against Other Bacteria in Soil, as Monitored by Indirect Phage Analysis
Authors: Germida James J. , Casida L. E.
Published: January 2020

An indirect phage analysis procedure was used to detect and follow the activity of the bacterial predator
Ensifer adhaerens
in situ in natural soil. The soil was percolated with an aqueous suspension of washed bacterial host cells so that the
E. adhaerens
cells naturally present in the soil would multiply in response to the host cells. The natural phage development which ensued against these multiplying
E. adhaerens
cells in the soil was then monitored by noting plaques which developed when the percolation fluid was plated with laboratory strains of
E. adhaerens
on laboratory media. The activities of the other members of the predation system that includes
E. adhaerens (Streptomyces
sp. strain 34 and a myxobacter) could not be monitored directly by phage analysis because phage were not found for them. Indirect monitoring was possible, however, because they were susceptible to attack by
E. adhaerens.
In general, the results were in agreement with previous observations by other methods of the predation sequence.
E. adhaerens
attacked
Micrococcus luteus, Streptomyces
sp. strain 34, and the myxobacter but did not attack several other possible species of hosts. It also did not respond to percolation of the soil with various nutrient solutions.
E. adhaerens
phage activity was not present in half of the soils percolated with
M. luteus
cells. This seemed to reflect too great a phage-host specificity for the technique as regards these soils, because
E. adhaerens
-like bacteria other than the strains used for plaquing were present in at least some of these soils. Although
E. adhaerens
did not attack
Escherichia coli
or
Pseudomonas aeruginosa
in soil, there was an overproduction of
E. adhaerens
phage if these bacteria were percolated simultaneously with
M. luteus
cells. The possibility is discussed that this represents an activation by
M. luteus
(or by a heat-extractable factor from it) of other bacterial predators that attack
E. coli
or
P. aeruginosa
and that these predators subsequently are themselves attacked by
E. adhaerens.
Effects of 2-Bromoethanesulfonic Acid and 2- Chloroethanesulfonic Acid on Acetate Utilization in a Continuous-Flow Methanogenic Fixed-Film Column
Authors: Bouwer Edward J. , McCarty Perry L.
Published: January 2020

2-Bromoethanesulfonic acid (BESA) and 2-chloroethanesulfonic acid (CESA) have been reported to be potent inhibitors of methane formation during methanogenic decomposition in batch cultures. However, in a laboratory-scale continuous-flow methanogenic fixed-film column containing a predominance of acetate-decarboxylating methanogens, BESA at 6 × 10
−4
M produced only a 41% inhibition of acetate utilization, and CESA at 5.4 × 10
−4
M produced a 37% inhibition of acetate utilization. BESA and CESA concentrations were not monitored in the effluent, so their fate is unknown. The organisms in the column were capable of degrading trace halogenated aliphatic compounds (∼30 μg/liter) with acetate (100 mg/liter) as the primary substrate. Previous exposure of the cells to halogenated organic compounds may have conferred resistance to BESA and CESA. Degradation of the inhibitor compounds is another possible explanation for the observed effects.
Plasmid linkage of a bacteriocin-like substance in Streptococcus lactis subsp. diacetylactis strain WM4: transferability to Streptococcus lactis
Authors: Scherwitz K M , Baldwin K A , McKay L L
Published: January 2020

Streptococcus lactis subsp. diacetylactis strain WM4 transferred lactose-fermenting and bacteriocin-producing (Bac+) abilities to S. lactis LM2301, a lactose-negative, streptomycin-resistant (Lac- Strr), plasmid-cured derivative of S. lactis C2. Three types of transconjugants were obtained: Lac+ Bac+, Lac+ Bac-, and Lac-Bac+.S. diacetylactis WM4 possessed plasmids of 88, 33, 30, 5.5, 4.8, and 3.8 megadaltons (Mdal). In Lac+ Bac+ transconjugants, lactose-fermenting ability was linked to the 33-Mdal plasmid and bacteriocin-producing ability to the 88-Mdal plasmid. Curing the 33-Mdal plasmid from Lac+ Bac+ transconjugants resulted in loss of lactose-fermenting ability but not bacteriocin-producing ability (Lac- Bac+). These strains retained the 88-Mdal plasmid. Curing of both plasmids resulted in a Lac- Bac- phenotype. The Lac+ Bac- transconjugant phenotype was associated with a recombinant plasmid of 55 or 65 Mdal. When these transconjugants were used as donors in subsequent matings, the frequency of Lac transfer was about 2.0 X 10(-2) per recipient plated, whereas when Lac+ Bac+ transconjugants served as donors, the frequency of Lac transfer was about 2.0 X 10(-5) per recipient plated. Also, Lac- Bac+ transconjugants were found to contain the 88-Mdal plasmid. The data indicate that the ability of WM4 to produce bacteriocin is linked to an 88-Mdal conjugative plasmid and that lactose-fermenting ability resides on a 33-Mdal plasmid.
Characterization of varicella-zoster virus enhancement by the pesticide carbaryl
Authors: Abrahamsen L H , Jerkofsky M
Published: January 2020

Further characterization of the viral enhancement system of varicella-zoster virus by the pesticide carbaryl (1-naphthyl-N-methylcarbamate) is presented. It was necessary to expose cells to the enhancing chemical during the period of virus replication to detect enhancement. The optimum time for the pretreatment is 20 to 24 h. Maximum enhancement of virus expression occurs 48 to 72 h post-inoculation. Treated cells cannot pass on to daughter cells the ability to produce increased amounts of virus. alpha-Naphthol, a metabolite of carbaryl, is also capable of enhancing virus replication; Guthion, another pesticide tested, did not enhance varicella-zoster virus. The stable cell line HEP-2 can be used in place of human embryonic lung cells to detect enhancement. Differences in enhancement levels were not due to cell lot, cell passage, or a change in the stability of the cell membrane to sonic disruption.
Controlling Morphological Instability of
Zymomonas mobilis
Strains in Continuous Culture
Authors: Fein Jared E. , Zawadzki Bogdan C. , Lawford Hugh G. , Lawford G. Ross
Published: January 2020

Growth of
Zymomonas mobilis
ATCC 29191 and CP4 in a continuous stirred tank fermentor resulted in the selection of stable flocculating variants. Factors responsible for enhancing the system pressures selective for the morphological variants were identified. By incorporating some modifications into the design of the fermentor, it was possible to achieve steady-state operation of the chemostat with both wild-type and flocculating strains. Biochemical and microscopic studies were performed to elucidate the mechanism of flocculation in
Z. mobilis
.
Fermentative degradation of polyethylene glycol by a strictly anaerobic, gram-negative, nonsporeforming bacterium, Pelobacter venetianus sp. nov
Authors: Schink B , Stieb M
Published: January 2020

The synthetic polyether polyethylene glycol (PEG) with a molecular weight of 20,000 was anaerobically degraded in enrichment cultures inoculated with mud of limnic and marine origins. Three strains (Gra PEG 1, Gra PEG 2, and Ko PEG 2) of rod-shaped, gram-negative, nonsporeforming, strictly anaerobic bacteria were isolated in mineral medium with PEG as the sole source of carbon and energy. All strains degraded dimers, oligomers, and polymers of PEG up to a molecular weight of 20,000 completely by fermentation to nearly equal amounts of acetate and ethanol. The monomer ethylene glycol was not degraded. An ethylene glycol-fermenting anaerobe (strain Gra EG 12) isolated from the same enrichments was identified as Acetobacterium woodii. The PEG-fermenting strains did not excrete extracellular depolymerizing enzymes and were inhibited by ethylene glycol, probably owing to a blocking of the cellular uptake system. PEG, some PEG-containing nonionic detergents, 1,2-propanediol, 1,2-butanediol, glycerol, and acetoin were the only growth substrates utilized of a broad variety of sugars, organic acids, and alcohols. The isolates did not reduce sulfate, sulfur, thiosulfate, or nitrate and were independent of growth factors. In coculture with A. woodii or Methanospirillum hungatei, PEGs and ethanol were completely fermented to acetate (and methane). A marine isolate is described as the type strain of a new species, Pelobacter venetianus sp. nov. Its physiology and ecological significance, as well as the importance and possible mechanism of anaerobic polyether degradation, are discussed.
Microtechnique for isolating fecal coliforms from soil
Authors: Hartel P G , Hagedorn C
Published: January 2020

A most-probable-number microtitration technique for isolating fecal coliforms from soil was developed. A correlation coefficient of 0.86, with a 95% confidence interval of 0.76 less than zeta less than 0.92, was obtained when this technique was compared with the standard elevated-temperature fecal coliform most-probable-number procedure.
Bacterial degradation of emulsan
Authors: Shoham Y , Rosenberg M , Rosenberg E
Published: January 2020

Emulsan is a polyanionic heteropolysaccharide bioemulsifier produced by Acinetobacter calcoaceticus RAG-1. A mixed bacterial population was obtained by enrichment culture that was capable of degrading emulsan and using it as a carbon source. From this mixed culture, an emulsan-degrading bacterium, termed YUV-1, was isolated. Strain YUV-1 is an aerobic, gram-negative, non-spore-forming, rod-shaped bacterium which grows best in media containing yeast extract. When placed on preformed lawns of A. calcoaceticus RAG-1, strain YUV-1 produced translucent plaques which grew in size until the entire plate was covered. Plaque formation was due to solubilization of the emulsan capsule of RAG-1. Plaque formation was not observed on emulsan-negative mutants of RAG-1. As a consequence of the solubilization of the emulsan capsule, RAG-1 cells became more hydrophobic, as determined by adherence to hexadecane. Growth of YUV-1 on a medium containing yeast extract and emulsan was biphasic. During the initial 24 h, cell concentration increased 10-fold, but emulsan was not degraded; during the lag in growth (24 to 48 h), emulsan was inactivated and depolymerized but not consumed; during the second growth phase (48 to 70 h) the depolymerized emulsan products were consumed.
Fed-batch approach to production of 2,3-butanediol by Klebsiella pneumoniae grown on high substrate concentrations
Authors: Yu E K , Saddler J N
Published: January 2020

The bioconversion of sugars present in wood hemicellulose to 2,3-butanediol by Klebsiella pneumoniae grown on high sugar concentrations was investigated. When K. pneumoniae was grown under finite air conditions in the presence of added acetic acid, 50 g of D-glucose and D-xylose per liter could be converted to 25 and 27 g of butanediol per liter, respectively. The efficiency of bioconversion decreased with increasing sugar substrate concentrations (up to 200 g/liter). Butanediol production at low sugar substrate concentrations was less efficient when the organism was grown under aerobic conditions; however, final butanediol values were higher for cultures grown on an initial sugar concentration of 150 g/liter, particularly when the inoculum was first acclimatized to high sugar levels. When a double fed-batch approach (daily additions of sugars together with yeast extract) was used under aerobic conditions, up to 88 and 113 g of combined butanediol and acetyl methyl carbinol per liter could be obtained from the utilization of 190 g of D-xylose and 226 g of D-glucose per liter, respectively.
Mesophilic Cellulolytic Clostridia from Freshwater Environments
Authors: Leschine S. B. , Canale-Parola E.
Published: January 2020

Eight strains of obligately anaerobic, mesophilic, cellulolytic bacteria were isolated from mud of freshwater environments. The isolates (C strains) were rod-shaped, gram negative, and formed terminal spherical to oval spores that swelled the sporangium. The guanine plus cytosine content of the DNA of the C strains ranged from 30.7 to 33.2 mol% (midpoint of thermal denaturation). The C strains fermented cellulose with formation primarily of acetate, ethanol, CO
2
, and H
2
. Reducing sugars accumulated in the supernatant fluid of cultures which initially contained ≥0.4% (wt/vol) cellulose. The C strains resembled
Clostridium cellobioparum
in some phenotypic characteristics and
Clostridium papyrosolvens
in others, but they were not identical to either of these species. The C strains differed from thermophilic cellulolytic clostridia (e.g.,
Clostridium thermocellum
) not only in growth temperature range but also because they fermented xylan and five-carbon products of plant polysaccharide hydrolysis such as
d
-xylose and
l
-arabinose. At 40°C, cellulose was degraded by cellulolytic mesophilic cells (strain C7) at a rate comparable to that at which
C. thermocellum
degrades cellulose at 60°C. Substrate utilization and growth temperature data indicated that the C strains contribute to the anaerobic breakdown of plant polymers in the environments they inhabit.
Use of murine myeloma protein M467 for detecting Salmonella spp. in milk
Authors: Smith A M , Jones C
Published: January 2020

This investigation introduces the use of an immunoglobulin A mouse myeloma protein for the detection of Salmonella spp. in milk. The immunoglobulin A protein M467 reacts with flagellin from a wide variety of serotypes. Two assays were developed which used an enzyme-linked immunosorbent assay (ELISA) and M467. Alkaline phosphatase was conjugated to M467 (M467-PH), and the presence of Salmonella dublin was detected by a competitive solid-phase ELISA and a membrane filtration ELISA. The competitive assay competed viable Salmonella spp. found in contaminated milk against polymerized flagellin or whole bacteria fixed to polyvinyl plates for binding by M467-PH. The membrane filtration method utilized a hydrophilic membrane for filtering the bacteria, which were then detected by the reaction with M467-PH and substrate. The sensitivity of the competitive solid-phase ELISA was 10(3) bacteria ml-1, whereas the filter membrane assay required the media containing the bacteria to be cultured in enrichment medium for 4 h before the assay to ensure detection. Either assay could be run within a typical 8-h work day. The filter membrane assay was not suitable for milk due to the high level of natural alkaline phosphatase activity in the liquid food.
Microbial Production of Optically Pure
l
-Iditol by Yeast Strains
Authors: Ogawa Mayumi , Sawada Toyoaki , Okuda Toru , Suhara Yasuji , Maruyama Hiromi B.
Published: January 2020

Several yeast strains belonging to genus
Candida
were found to selectively hydrogenate
l
-sorbose with enantiomeric specificity, yielding optically pure
l
-iditol in the culture broth. The most active strain, isolated from a commercial lemon, was identified as
Candida intermedia
, which produced 50 g of
l
-iditol per liter from 150 g of
l
-sorbose per liter during a 5-day fermentation period (35% yield).
Effects of nutrient deprivation on Vibrio cholerae
Authors: Baker R M , Singleton F L , Hood M A
Published: January 2020

Environmental and clinical strains of Vibrio cholerae were exposed to nutrient-free artificial seawater and filtered natural seawater microcosms for selected time intervals and examined for changes in cell morphology and number. Cells observed by transmission electron and epifluorescence microscopy were found to undergo gross alterations in cell morphology with time of exposure. The vibroid cells decreased in volume by 85% and developed into small coccoid forms surrounded by remnant cell walls. The initial number of cells inoculated into nutrient-free microcosms (culturable count and direct viable count) increased 2.5 log10 within 3 days, and even after 75 days the number of viable cells was still 1 to 2 log10 higher than the initial inoculum size. Nutrient-depleted coccoid-shaped cells were restored to normal size and assumed a bacillary shape within 3 h and began to divide within 5 h after nutrient supplementation. The increase in cell number and decrease in cell volume under nutrient-depleted conditions, as well as the rapid growth response after nutrient supplementation, may describe some of the survival mechanisms of V. cholerae in the aquatic environment.
Long-Term Changes in Chemostat Cultures of
Cytophaga johnsonae
Authors: Höfle Manfred G.
Published: January 2020

Long-term studies with a gliding, heterotrophic bacterium,
Cytophaga johnsonae
, were conducted in a glucose-limited chemostat at a high and a low dilution rate. To test the stability of the steady state during long-term experiments the following parameters were monitored: optical density, glucose concentration, glucose uptake potential, ATP content of the cells, and plate counts on two different agar media. Biomass remained relatively constant, although the observed changes could have been possible in both directions. During all steady states, glucose uptake showed a stepwise increase and the glucose concentration showed a corresponding decrease. Glucose uptake potential and glucose concentration in the chemostat were inversely proportional. The ATP content of the cells varied up to 33% during the steady state, but did not show a general trend. After long cultivation in all chemostats, plate counts on both agars dropped to values less than 20% of the original steady-state level. These decreases were due to an inability of the cells to grow on agar plates, not to a lack of vitality of the cells in the chemostat. This study showed that even during shorter chemostat runs, e.g., 1 week, changes in important parameters with the steady state must be expected, especially in the uptake potential and the concentration of the limiting substrate.
Inactivation of Naegleria gruberi cysts by chlorinated cyanurates
Authors: Engel J P , Rubin A J , Sproul O J
Published: January 2020

The resistance of Naegleria gruberi cysts to chlorine in the presence of cyanuric acid was compared at pH 5 and 7. An amperometric membrane electrode was used to measure HOCl concentrations independently of the chlorinated cyanurate species, thus permitting an analysis of the role of free chlorine versus chlorinated cyanurates in cyst inactivation. In the presence of cyanuric acid, the products of the HOCl residual and the contact time required for 99% cyst inactivation were 8.5 mg . min/liter and 13.9 mg . min/liter at pH 5 and 7, respectively. The Watson's Law coefficients of dilution (n) were 1.3 and 1.6 at pH 5 and 7, respectively. The results strongly suggest that HOCl is the predominant cysticide with no measurable cysticidal effect of the chlorinated cyanurate species.
Metabolism of 7,12-dimethylbenz[a]anthracene by Cunninghamella elegans
Authors: Wong L K , Dru J , Lin L S , Knapp J
Published: January 2020

The metabolites of 7,12-dimethylbenz[a]anthracene (DMBA), a carcinogenic polycyclic aromatic hydrocarbon, in cultures of Cunninghamella elegans were isolated by high-pressure liquid chromatography and characterized by UV spectroscopy and mass spectrometry. The major metabolites were DMBA-trans-8,9-dihydrodiol and DMBA-trans-3,4-dihydrodiol. The 7-hydroxymethyl and the 12-hydroxymethyl derivatives of these dihydrodiol metabolites were also formed. The metabolic profile described in this report contrasts with those obtained in our earlier experiments in which the incubation of DMBA with Pseudomonas aeruginosa and Penicillium notatum produced no dihydrodiol metabolites but only methyl-hydroxylated metabolites.
Comparison of Vogel-Johnson and Baird-Parker media for membrane filtration recovery of staphylococci in swimming pool water
Authors: Klapes N A
Published: January 2020

Previous studies have indicated that the coagulase-positive Staphylococcus (Staphylococcus aureus) has potential as a useful indicator of the infection hazard associated with the use of swimming pools and other recreational waters. However, before this indicator system can be used effectively, a recovery system that is sufficiently selective, accurate, and reliable for the enumeration of S. aureus must be developed. In this study, Vogel-Johnson (VJ) and Baird-Parker (BP) agars were compared for efficacy in the primary isolation and recovery of S. aureus from swimming pool water. For equal sample volumes of pool water containing adequate free chlorine residual, VJ agar was found to be more selective for staphylococcal species and less inhibitory to general cell growth than was BP agar. However, neither medium was found to be sufficiently differential to permit the accurate identification of S. aureus. In contrast, water samples obtained from a swimming pool containing very low levels of chlorine (none of which was in the free form) showed abundant growth of staphylococci on both test media, with both VJ and BP agars showing increased sensitivity for the detection of S. aureus. Thus, VJ and BP agars show increased sensitivity for the detection of coagulase-positive staphylococci from unchlorinated versus chlorinated waters.