bluuebunny/crossref_metadata_2025 huggingface dataset:
Preservation of Rhizobium viability and symbiotic infectivity by suspension in water
Authors: Crist D K , Wyza R E , Mills K K , Bauer W D , Evans W R
Published: January 2020

Three Rhizobium japonicum strains and two slow-growing cowpea-type Rhizobium strains were found to remain viable and able to rapidly modulate their respective hosts after being stored in purified water at ambient temperatures for periods of 1 year and longer. Three fast-growing Rhizobium species did not remain viable under the same water storage conditions. After dilution of slow-growing Rhizobium strains with water to 10(3) to 10(5) cells ml-1, the bacteria multiplied until the viable cell count reached levels of between 10(6) and 10(7) cells ml-1. The viable cell count subsequently remained fairly constant. When the rhizobia were diluted to 10(7) cells ml-1, they did not multiply, but full viability was maintained. If the rhizobia were washed and suspended at 10(9) cells ml-1, viability slowly declined to 10(7) cells ml-1 during 9 months of storage. Scanning electron microscopy showed that no major morphological changes took place during storage. Preservation of slow-growing rhizobia in water suspensions could provide a simple and inexpensive alternative to current methods for the preservation of rhizobia for legume inoculation.
Removal of enteric viruses from surface water at eight waterworks in The Netherlands
Authors: van Olphen M , Kapsenberg J G , van de Baan E , Kroon W A
Published: January 2020

Eight waterworks in The Netherlands, which use surface water as their raw water source, were sampled repeatedly between November 1978 and June 1981. At five waterworks , 30 of 45 samples of raw water contained viruses. Of 55 samples of partially purified water, 11 were virus positive, including 8 after coagulation, sedimentation, and rapid sand filtration, 2 after storage, coagulation, sedimentation, transport chlorination, and rapid sand filtration, and 1 after storage in open reservoirs for 5 months. No viruses were detected in 100 samples of drinking water of 500 liters each from six waterworks . Most isolated viruses were typed, and a great variety of human enteroviruses were found, reflecting both pollution of raw water sources with sewage and vaccination with oral polio vaccine in neighboring countries.
Biokinetic analyses of adaptation and succession: microbial activity in composting municipal sewage sludge
Authors: McKinley V L , Vestal J R
Published: January 2020

The interactions between temperature and the microbial communities in composting municipal sewage sludge were studied to determine the optimal temperature range for efficient decomposition (stabilization) of the sludge. Information concerning thermophilic successions in such communities was also obtained. Samples were taken from several different temperature areas in a production-scale composting pile throughout the 19-day processing run. Optimum temperatures for microbial activity, determined as the rate of [14C]acetate incorporation into microbial lipids, were determined for each sample. Biomass was determined from the lipid phosphate content of the sample. Maximal activities were generally found in samples coming from lower-temperature areas (25 to 45 degrees C), whereas samples from high temperatures (55 to 74 degrees C) usually had relatively little activity. The temperature giving the optimum activity in samples incubated at a variety of temperatures during the assay tended to increase as the composting time progressed, but never exceeded about 50 degrees C. Many of these temperature response curves were similar in nature to curves reported for purified enzyme systems and pure cultures of bacteria. Comparisons of the apparent energies of activation calculated for different temperature ranges over time also indicated that the overall community was better adapted to higher temperatures during the latter part of the composting run. It was also found that the relationship between the apparent energies of activation and the apparent energies of inactivation (apparent heats of denaturation) consistently changed with sample temperature throughout the composting run, suggesting that the microbial communities from hotter samples were better adapted to high temperatures than those from cooler samples, and vice versa.(ABSTRACT TRUNCATED AT 250 WORDS)
Larvicidal activity of Bacillus thuringiensis subsp. israelensis in the dipteran Haematobia irritans
Authors: Temeyer K B
Published: January 2020

A strain of Bacillus thuringiensis subsp. israelensis was found to be larvicidal to horn flies, Haematobia irritans (L. [Diptera:Muscidae]). The toxic activity was particulate, appeared during sporulation, and could be prevented by the addition of streptomycin before sporulation. Density gradient centrifugation in Renografin was used to separate endospores, crystals, and low-density particulate matter (fraction 3) from sporulated preparations. Larvicidal activity was restricted to purified crystals and fraction 3, indicating that delta-endotoxin of B. thuringiensis subsp. israelensis was active against horn fly larvae. Purified crystals produced mortality during larval feeding stages, but not pupal stages. Fraction 3 produced significant mortality during both larval and pupal stages. The mortality data indicated the presence of at least two dipteran-active toxins.
Peptostreptococcus productus strain that grows rapidly with CO as the energy source
Authors: Lorowitz W H , Bryant M P
Published: January 2020

Anaerobic bacteria were enriched with a sewage digestor sludge inoculum and a mineral medium supplemented with B-vitamins and 0.05% yeast extract and with a 50% CO-30% N2-20% CO2 (2 atm [202 kPa]) gas phase. Microscopic observation revealed an abundance of gram-positive cocci, 1.0 by 1.4 micron, which occurred in pairs or chains. The coccus, strain U-1, was isolated by using roll tubes with CO as the energy source. Based on morphology, sugars fermented, fermentation products from glucose (H2, acetate, lactate, and succinate), and other features, strain U-1 was identified as Peptostreptococcus productus IIb (similar to the type strain). The doubling time with up to 50% CO was 1.5 h; acetate and CO2 were the major products. In addition, no significant change in the doubling time was observed with 90% CO. Some stock strains were also able to use CO, although not as well. Strain U-1 produced acetate during growth with H2-CO2. Other C1 compounds did not support growth. Most probable numbers of CO utilizers morphologically identical with strain U-1 were 7.5 X 10(6) and 1.1 X 10(5) cells per g for anaerobic digestor sludge and human feces, respectively.
Methanosarcina acetivorans
sp. nov., an Acetotrophic Methane-Producing Bacterium Isolated from Marine Sediments
Authors: Sowers Kevin R. , Baron Stephen F. , Ferry James G.
Published: January 2020

A new acetotrophic marine methane-producing bacterium that was isolated from the methane-evolving sediments of a marine canyon is described. Exponential phase cultures grown with sodium acetate contained irregularly shaped cocci that aggregated in the early stationary phase and finally differentiated into communal cysts that released individual cocci when ruptured or transferred to fresh medium. The irregularly shaped cocci (1.9 ± 0.2 mm in diameter) were gram negative and occurred singly or in pairs. Cells were nonmotile, but possessed a single fimbria-like structure. Micrographs of thin sections showed a monolayered cell wall approximately 10 nm thick that consisted of protein subunits. The cells in aggregates were separated by visible septation. The communal cysts contained several single cocci encased in a common envelope. An amorphous form of the communal cyst that had incomplete septation and internal membrane-like vesicles was also present in late exponential phase cultures. Sodium acetate, methanol, methylamine, dimethylamine, and trimethylamine were substrates for growth and methanogenesis; H
2
-CO
2
(80:20) and sodium formate were not. The optimal growth temperature was 35 to 40°C. The optimal pH range was 6.5 to 7.0. Both NaCl and Mg
2+
were required for growth, with maximum growth rates at 0.2 M NaCl and 0.05 M MgSO
4
. The DNA base composition was 41 ± 1% guanine plus cytosine.
Methanosarcina acetivorans
is the proposed species. C2A is the type strain (DSM 2834, ATCC 35395).
Isolation of
Yersinia ruckeri
Bacteriophages
Authors: Stevenson R. M. W. , Airdrie D. W.
Published: January 2020

Eight bacteriophages effective against
Yersinia ruckeri
, the enteric redmouth disease bacterium, were isolated. Phage YerA41, a tailed icosahedral virus isolated from sewage enrichments, lysed 34 of 35 strains of
Y. ruckeri
serovar I, but was inactive against 15 strains belonging to three other serological groups. Six other phages lysed strains of serovars II, V, and I′, a subgroup of serovar I. YerL62, a phage obtained by mitomycin C induction, was specific for one of three serovar V strains. These bacteriophages, particularly YerA41, have potential value for fish disease diagnostic work.
Use of Gas-Liquid Chromatography to Determine the End Products of Growth of Lactic Acid Bacteria
Authors: Thornhill Patrick J. , Cogan Timothy M.
Published: January 2020

A simple gas-liquid chromatographic procedure for analyzing ethanol, acetic acid, acetoin, and racemic and
meso
-2,3-butylene glycol in broth media is described. Overnight broth cultures were filtered or centrifuged, and the filtrate or supernatant was treated with formic acid to aid separation of volatile fatty acids. Samples were then directly analyzed by gas-liquid chromatography on a 20% Tween 80-Chromosorb W-AW column and propionic acid as an internal standard. A complete analysis took ca. 8 min. The method can be used to distinguish homofermentative from heterofermentative lactic acid bacteria based on the level of ethanol produced and citrate-utilizing from non-citrate-utilizing lactic acid bacteria based on the levels of acetic acid produced. The method also has potential in distinguishing other bacterial fermentations. Of the 13 species of lactic acid bacteria tested,
Streptococcus lactis
subsp.
diacetylactis
was the major producer of 2,3-butylene glycol (total range, 0.3 to 3.5 mM), and, except for strain DRC1, both the racemic and
meso
isomers were produced in approximately equal amounts.
Seasonal Study of Methane Oxidation in Lake Washington
Authors: Lidstrom Mary E. , Somers Leslie
Published: January 2020

The distribution of methane and methane-oxidizing bacteria in the water column of Lake Washington was determined monthly for 1 year. The methane profiles were relatively constant, with little stratification and low concentrations (0.05 to 0.5 μM). The number of methane-oxidizing bacteria detected by a filter-plating method was routinely <1/ml throughout the water column, and no incorporation or oxidation of methane was detected by radioisotopic labeling, even after methane was added. However, samples taken from the sediment-water interface contained as much as 3 μM methane and 50 CFU of methane-oxidizing bacteria per ml and showed significant rates of methane oxidation and incorporation. To define the region of maximum activity more precisely, vertical profiles of the sediment were examined. The concentration of methane increased with depth to a maximum of 150 to 325 μM at 2.5 cm, and significant rates of methane oxidation were found within the top 2.5 cm. The apparent

K
m

s for methane and oxygen were determined for samples from the top 1.0 cm of the sediment and found to be ca. 10 and 20 μM, respectively. Projected values for methane oxidation rates suggested that maximum methane oxidation occurred in the top 0.5 cm of the sediment.
Production of Nitric Oxide in Loam Under Aerobic and Anaerobic Conditions
Authors: Johansson C. , Galbally I. E.
Published: January 2020

Measurements of gas flow through soil columns of loam from Kjettslinge, Uppland, Sweden, gave average NO production rates of 0.06 ± 0.01 ng of NO N g of soil
−1
min
−1
in aerobic conditions and 3.7 ± 0.6 ng of NO N g of soil
−1
min
−1
in anaerobic conditions at 25°C. Approximately 30% of the NO
3
−
loss in anaerobic conditions was as NO. In aerobic conditions an equilibrium concentration for NO was found. Above this concentration there was uptake of NO. Autoclaved samples indicated that less than 10% of the NO production was abiological, and there was no abiological NO uptake. The NO production reached anaerobic rates at soil O
2
levels between 0.5 and 0.05%.
Detection of enteric viruses in treated drinking water
Authors: Keswick B H , Gerba C P , DuPont H L , Rose J B
Published: January 2020

The occurrence of viruses in conventionally treated drinking water derived from a heavily polluted source was evaluated by collecting and analyzing 38 large-volume (65- to 756-liter) samples of water from a 9 m3/s (205 X 10(6) gallons [776 X 10(6) liters] per day) water treatment plant. Samples of raw, clarified, filtered, and chlorinated finished water were concentrated by using the filter adsorption-elution technique. Of 23 samples of finished water, 19 (83%) contained viruses. None of the nine finished water samples collected during the dry season contained detectable total coliform bacteria. Seven of nine finished water samples collected during the dry season met turbidity, total coliform bacteria, and total residual chlorine standards. Of these, four contained virus. During the dry season the percent removals were 25 to 93% for enteric viruses, 89 to 100% for bacteria, and 81% for turbidity. During the rainy season the percent removals were 0 to 43% for enteric viruses, 80 to 96% for bacteria, and 63% for turbidity. None of the 14 finished water samples collected during the rainy season met turbidity standards, and all contained rotaviruses or enteroviruses.
Models for mineralization kinetics with the variables of substrate concentration and population density
Authors: Simkins S , Alexander M
Published: January 2020

The rates of mineralization of [14C]benzoate by an induced population of Pseudomonas sp. were measured at initial substrate concentrations ranging from 10 ng/ml to 100 micrograms/ml. Plots of the radioactivity remaining in the culture were fit by nonlinear regression to six kinetic models derived from the Monod equation. These models incorporate only the variables of substrate concentration and cell density. Plots of the mineralization kinetics in cultures containing low, intermediate, and high initial substrate concentrations were well fit by first-order, integrated Monod, and logarithmic kinetics, respectively. Parameters such as maximum specific growth rate, half-saturation constant, and initial population density divided by yield agreed between cultures to within a factor of 3.4. Benzoate mineralization by microorganisms in acclimated sewage was shown to fit logistic (sigmoidal), Monod, and logarithmic kinetics when the compound was added at initial concentrations of 0.1, 1.0, and 10 micrograms/ml, respectively. The mineralization of 10 micrograms of benzoate per ml in sewage also followed logarithmic kinetics in the absence of protozoa. It is concluded that much of the diversity in shapes of mineralization curves is a result of the interactions of substrate concentration and population density. Nonlinear regression with models incorporating these variables is a valuable means for analysis of microbial mineralization kinetics.
Separation of Fungal Propagules by Partition in Aqueous Polymer Two-Phase Systems
Authors: Blomquist Göran K. , Ström Gunnar B. , Söderström Bengt
Published: January 2020

Conidia of
Penicillium chrysogenum
and
Penicillium frequentans
and sporangiospores of
Rhizopus rhizopodiformis, Rhizomucor pusillus
, and
Mucor racemosus
were subjected to partition in aqueous polymer two-phase systems. The partition behavior differed drastically between the conidia of the two
Penicillium
species and the sporangiospores of the three species of phycomycetes. This difference in partition behavior can be used for purification of fungi belonging to different taxonomical groups.
P. frequentans
was completely separated from
M. racemosus
by two extractions, whereas four extractions were needed to purify
M. racemosus.
This method was used on an air sample from a locality where wood fuel chips are handled. The conidia of the fungi
Trichoderma viride
and
Rhizopus rhizopodiformis
were removed completely by only two extractions.
Enzyme-linked immunosorbent assay for detection of Salmonella lipopolysaccharide in poultry specimens
Authors: Rigby C E
Published: January 2020

An enzyme-linked immunosorbent assay (ELISA) for detection of salmonellae was developed and evaluated by using artificially contaminated specimens of poultry feed, feces, litter, or carcass rinsings, and naturally contaminated water samples. Specimens containing salmonellae of serogroups B or C2 inhibited the binding of polyvalent anti-O serum to microtiter plate wells coated with lipopolysaccharide of Salmonella typhimurium (serogroup B) or Salmonella albany (serogroup C2), respectively. Treatment of specimens with Rhozyme 41 (a protease) inhibited nonspecific reactions. The ELISA detected 106 of 111 culture-positive specimens contaminated with salmonellae of serogroups B or C2. Nineteen of 20 specimens containing salmonellae of serogroup C1 and all of 36 culture-negative specimens were ELISA negative. All seven water samples that contained salmonellae of serogroups B or C2, including three that were culture positive only after delayed secondary enrichment, were ELISA positive. Seven of the nine water samples that contained salmonellae of other serogroups, and all 38 culture-negative samples, were ELISA negative. The ELISA was simple to perform, produced results in 48 h, and was more economical than culture methods.
Responses of
Sorghum
and
Pennisetum
Species to the N
2
-Fixing Bacterium
Azospirillum brasilense
Authors: Smith Rex L. , Schank S. C. , Milam J. R. , Baltensperger A. A.
Published: January 2020

Three field inoculation experiments, two in Florida and one in New Mexico, were conducted with
Azospirillum brasilense
Cd. Each of the Florida experiments evaluated two crop species. One species in each of the Florida experiments responded to inoculation with a significant dry matter yield increases of 11 to 24% and nitrogen yield increases of 9 to 39%. No inoculation response was noted in the New Mexico experiment. The responding species were
Sorghum bicolor
(L.) Moench (sorghum) and the interspecific hybrid between
Pennisetum americanum
(L.) K. Schum. (pearl millet) and
P. purpureum
Schumach. (napiergrass). Nonresponding species were pearl millet (Florida) and
Sorghum sudanense
(Piper) Staph. (New Mexico). Acetylene reduction activity of inoculated plots in Florida was low, showing no increase over the natural uninoculated background rates and, in one case, was negatively correlated with yield. Acetylene reduction activity was not measured in New Mexico. In Florida,
A. brasilense
populations were found to decline from 5 × 10
3
to 5 × 10
2
bacteria g of soil
−1
in about 3 weeks (quadratic regressions). Continued decline to less than 10
2
by week 5 indicated that the inoculated bacteria did not become established in the soil in high numbers. The
A. brasilense
population declined at about the same rate in the New Mexico experiment. The erractic inoculation responses in these experiments are similar to those observed in earlier work at the University of Florida. The lack of acetylene reduction activity response to inoculation and the rapid population decline of the inoculated bacteria suggest that N
2
fixation is not the major mechanism causing yield responses after inoculation.
Development and testing of a filter system for isolation of Giardia lamblia cysts from water
Authors: Hausler W J , Davis W E , Moyer N P
Published: January 2020

An inexpensive, practical, and reliable method for isolation of Giardia lamblia cysts from potable and environmental water has been developed from commercially available components. This system was successfully used to isolate cysts from well water associated with a family outbreak of giardiasis.
Naphtho-gamma-pyrone production by Aspergillus niger isolated from stored cottonseed
Authors: Ehrlich K C , DeLucca A J , Ciegler A
Published: January 2020

Aspergillus niger was found to be the predominant fungal contaminant of stored cottonseed. Seven strains were isolated and grown on rice. The hexane-insoluble material from methylene chloride extracts of 2-week-old cultures contained components toxic to mice. Based on high-pressure thin-layer and liquid chromatographic analyses, the major components in the mixture were eight different naphtho-gamma-pyrones. Of these, the hydrated dimeric naphthopyrones aurasperones B and C occurred in higher yield than aurasperones A, iso-A, and D and the monomeric naphthopyrones flavasperone and rubrofusarin, all of which were present in the mixture. In addition, fonsecin monomethyl ether was isolated. This metabolite may be a precursor in the biosynthesis of the hydrated aurasperones; it has not been identified previously as a metabolite of A. niger. The relative amounts of the different naphthopyrones were dependent on both the growth substrate and the fungal isolate.
Anaerobic degradation of 2-aminobenzoate (anthranilic acid) by denitrifying bacteria
Authors: Braun K , Gibson D T
Published: January 2020

In the presence of oxygen many aminoaromatic compounds polymerize to form recalcitrant macromolecules. To circumvent undesirable oxidation reactions, the anaerobic biodegradation of a simple member of this class of compounds was investigated. Two strains of bacteria were isolated which degrade 2-aminobenzoate anaerobically under denitrifying conditions, with nitrate as the terminal electron acceptor. Both organisms, which were assigned to the genus Pseudomonas, oxidized 2-aminobenzoate completely to CO2 and NH4+. Nitrate was reduced to nitrite. When nitrate was deplete from the growth medium the accumulated nitrite was reduced to nitrogen. The results establish a model system for the anaerobic, rapid, and complete oxidation of an aminoaromatic compound.
Identical 5S rRNA nucleotide sequence of Vibrio cholerae strains representing temporal, geographical, and ecological diversity
Authors: MacDonell M T , Colwell R R
Published: January 2020

Enzymatic determination of the nucleotide sequence of 5S rRNA prepared from a Vibrio cholerae non-O1 serovar isolated from a canal in Louisiana in 1978 revealed it to be identical to that of V. cholerae O1 isolated in 1905 from a pilgrim at the E1 Tor quarantine station. The two strains are associated with sharply contrasting habitats. Ranges of variation of 5 to 15% in procaryotic 5S rRNA sequences between species are typical; variation within species may be 2% or greater. Because the 5S rRNA sequences were identical, it is concluded that they have a common phylogenic origin.
Size of Suspended Bacterial Cells and Association of Heterotrophic Activity with Size Fractions of Particles in Estuarine and Coastal Waters
Authors: Palumbo Anthony V. , Ferguson Randolph L. , Rublee Parke A.
Published: January 2020

The size of bacteria and the size distribution of heterotrophic activity were examined in estuarine, neritic, and coastal waters. The data indicated the small size of suspended marine bacteria and the predominance of free-living cells in numerical abundance and in the incorporation of dissolved amino acids. The average per-cell volume of suspended marine bacteria in all environments was less than 0.1 μm
3
. Cell volume ranged from 0.072 to 0.096 μm
3
at salinities of 0 to 34.3‰ in the Newport River estuary, N.C., and from 0.078 to 0.096 μm
3
in diverse areas of the Gulf of Mexico. Thus, the free-living bacteria were too small to be susceptible to predation by copepods. In the Newport River estuary, ca. 93 to 99% of the total number of cells and 75 to 97% of incorporated tritium (from
3
H-labeled mixed amino acids) retained by a 0.2-μm-pore-size filter passed through a 3.0-μm-pore-size filter. Although the amino acid turnover rate per cell was higher for the bacteria in the >3.0-μm size fraction than in the <3.0-μm size fraction, the small number of bacteria associated with the >3.0-μm size particles resulted in the low relative contribution of attached bacteria to total heterotrophic activity in the estuary. For coastal and neritic samples, collected off the coast of Georgia and northeast Florida and in the plume of the Mississippi River, 56 to 98% of incorporated label passed through a 3.0-μm-pore-size filter. The greatest activity in the >3.0-μm fraction in the Georgia Bight was at nearshore stations and in the bottom samples. Our data were consistent with the hypothesis that resuspension of bottom material is an important factor in influencing the proportion of heterotrophic activity attributable to particle-associated bacteria.
Interaction of
Pseudomonas solanacearum
Lipopolysaccharide and Extracellular Polysaccharide with Agglutinin from Potato Tubers
Authors: Duvick Jonathan P. , Sequeira Luis
Published: January 2020

In vitro binding assays were used to study the possible role of a cell wall agglutinin in the attachment to plant cell walls of avirulent strains of the wilt pathogen,
Pseudomonas solanacearum.
In a nitrocellulose filter assay, radioactively labeled lipopolysaccharide (LPS) from the virulent strain, K60, and the avirulent strain, B1, and extracellular polysaccharide (EPS) from K60 were bound quantitatively by the agglutinin extracted from Katahdin potato tubers. The LPS from B1 had significantly greater agglutinin-binding affinity than that from K60 but not after treatment with deoxycholate, which improved solubility. Highly purified chitotetraose did not inhibit binding of K60 LPS to agglutinin, but binding was inhibited by EPS as well as by diverse anionic polymers (DNA, dextran sulfate, xanthan). Binding of agglutinin to EPS and LPS was inhibited at ionic strengths greater than 0.03 and 0.15 M, respectively. It was concluded that electrostatic charge-charge interactions could account for binding of LPS and EPS to potato agglutinin.
Invalidity of the Concept of Slow Growth and Alkali Production in Cowpea Rhizobia
Authors: Hernandez Blanca S. , Focht Dennis D.
Published: January 2020

A total of 103 rhizobial strains representing the cowpea miscellany and
Rhizobium japonicum
were studied with regard to growth rate, glucose metabolic pathways, and pH change in culture medium. Doubling times ranged from 1.4 ± 0.04 to 44.1 ± 5.2 h; although two populations of “fast-growing” and “slow-growing” rhizobia were noted, they overlapped and were not distinctly separated. Twenty-four strains which had doubling times of less than 8 h all showed NADP-linked 6-phosphogluconate dehydrogenase (6-PGD) activity, whereas only one slow-growing strain (doubling time, 10.8 ± 0.9 h) of all those tested showed 6-PGD activity. Doubling times among fast growers could not be explained solely by the presence or absence of 6-PGD activity (
r
2
= 0.14) because the tricarboxylic acid cycle and the Emden-Meyerhoff-Parnas pathway were operative in both 6-PGD-positive and 6-PGD-negative strains. Growth rate and pH change were unrelated to each other. Fast- or slow-growing strains were not associated with any particular legume species or group of species from which they were originally isolated, with the exception of
Stylosanthes
spp., all nine isolates of which were slow growers. We conclude that 6-PGD activity is a more distinctive characteristic among physiologically different groups of rhizobia than doubling times and that characterization of the cowpea rhizobia as slow-growing alkali producers is an invalid concept.
Effect of 3-Phenylpropanoic Acid on Capsule and Cellulases of
Ruminococcus albus
8
Authors: Stack Robert J. , Hungate Robert E.
Published: January 2020

The morphology and cellulases of
Ruminococcus albus
8 were markedly affected by the inclusion of 3-phenylpropanoic acid (PPA) in a defined growth medium. PPA-grown bacteria produced substantial quantities of cell-bound cellulase, as well as a very high-molecular-weight extracellular enzyme and lesser amounts of two low-molecular-weight enzymes. PPA-deprived bacteria produced greater total amounts of cellulase, but all of it exists in soluble, low-molecular-weight forms. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that the availability of PPA did not affect the kinds of proteins produced, but the distribution of two major proteins between cells and supernatant was PPA dependent. These two proteins (85 and 102 kilodaltons) were primarily associated with the cells of PPA-grown bacteria but were found chiefly in the supernatants of PPA-deprived cultures. Examination of thin sections of PPA-grown
R. albus
8 by transmission electron microscopy showed a lobed ruthenium red-staining capsule surrounding the cell wall, as well as small vesicular structures (diameter, 0.05 to 0.06 μm) which appeared to aggregate into larger spherical units (diameter, 0.2 to 0.3 μm). In contrast, thin sections of PPA-deprived cells were devoid of vesicles and showed little or no capsule surrounding the cells.
Production and Properties of Extracellular Endoxylanase from
Neurospora crassa
Authors: Mishra Chittra , Keskar Sulbha , Rao Mala
Published: January 2020

Neurospora crassa
870 produced 14 and 0.025 U of extracellular xylanase (1,4-β-
d
-xylan xylanohydrolase; EC 3.2.1.8) and β-xylosidase (1,4-β-xylan xylohydrolase; EC 3.2.1.37) per ml, respectively, in 4 days when commercial xylan was used as a carbon source. The effects of pH and carbon sources on xylanase production by
N. crassa
are discussed. Two xylanases (I and II) were purified and had pI values of 4.8 and 4.5 and molecular weights of 33,000 and 30,000. The maximum degree of hydrolysis of xylan by the extracellular culture broth was 66% in 4 h. The end products of xylan hydrolysis by xylanase I and II showed the presence of xylose, xylobiose, xylotriose, xylotetraose, xylopentose, and arabinose, indicating that they are endoxylanases capable of hydrolyzing 1,3-α-
l
-arabinofuranosyl branch points. Both xylanases showed activity toward carboxymethyl cellulose but no activity toward
para
-nitrophenyl-β-
d
-xyloside or laminarin. Xylanase I showed appreciable activity toward
para
-nitrophenyl-β-
d
-glucoside, whereas xylanase II was inactive.
Differences Between Lipopolysaccharide Compositions of Plant Pathogenic and Saprophytic
Pseudomonas
Species
Authors: Anderson A. J.
Published: January 2020

Lipopolysaccharides (LPS) were obtained by washing cells of plant pathogenic and saprophytic
Pseudomonas
species with saline (fraction 1) and then with saline-EDTA (fraction 2). The cells subsequently were extracted with phenol to yield a third aqueous preparation (fraction 3). Each fraction type contained the LPS components, lipid A, heptose, 2-keto-3-deoxy sugar, and neutral and amino sugars. The neutral sugar compositions of fractions 1, 2, and 3, although similar within a species, differed between the
Pseudomonas
species. The LPS of two pathovars (pv.) of
Pseudomonas syringae
had glucose and rhamnose as major components: 13 (±3)% glucose and 87 (±3)% rhamnose for
P. syringae
pv.
pisi
and 18 (±5)% glucose and 76 (±2)% rhamnose for
P. syringae
pv.
syringae
. Fucose was present in addition to glucose and rhamnose for
P. syringae
pv.
phaseolicola
(68 [±8]% rhamnose, 14 [±1]% fucose, and 14 [±5]% glucose) and
P. syringae
pv.
tabaci
(24 [±2]% rhamnose, 54 [±3]% fucose, and 17 [±1]% glucose). The LPS from different races of
P. syringae
pv.
pisi
and
P. syringae
pv.
phaseolicola
could not be distinguished by neutral sugar composition. Three saprophytic species,
P. aeruginosa, P. fluorescens
, and
P. putida
, also produced LPS which had different proportions of rhamnose, fucose, and glucose. The LPS from three isolates of
P. putida
were distinct in possessing a high proportion of amino sugar and containing glucose as the major neutral sugar component (86 to 100%). The LPS fractions from plant pathogenic and saprophytic
Pseudomonas
species did not elicit browning or phytoalexin production in treated dark red kidney bean cotyledons or red Mexican bean leaves. Rather, chlorosis of the LPS-treated leaf tissue was observed.
Conjugative Plasmid in
Corynebacterium flaccumfaciens
subsp.
oortii
That Confers Resistance to Arsenite, Arsenate, and Antimony(III)
Authors: Hendrick Carol A. , Haskins William P. , Vidaver Anne K.
Published: January 2020

Gene transfer systems for phytopathogenic corynebacteria have not been reported previously. In this paper we describe a conjugative 46-megadalton plasmid (pDG101) found in
Corynebacterium flaccumfaciens
subsp.
oortii
CO101 that mediates resistance to arsenite, arsenate, and antimony(III). Transfer of the plasmid from CO101 to four other strains from the
C. flaccumfaciens
group occurred between cells immobilized on nitrocellulose filters or on agar surfaces. Transconjugant strains expressed the same levels of metal resistance as the donor strain and were able to act as donor strains in subsequent matings. The physical presence of the plasmid was detected by agarose gel electrophoresis. Arsenite-sensitive derivatives of the donor and transconjugant strains were obtained after heat treatment; these were cured of pDG101.
Pectinolytic enzymes of oral spirochetes from humans
Authors: Weber F H , Canale-Parola E
Published: January 2020

Five strains of obligately anaerobic, pectin-fermenting spirochetes were isolated from the subgingival plaque of humans. The strains produced two extracellular enzymatic activities that functioned in pectin degradation. One of these enzymatic activities was pectin methylesterase (EC 3.1.1.11), and the other was pectate lyase (EC 4.2.2.2) of the endo type. The data indicate that the cumulative action of these two enzymatic activities brought about depolymerization of pectin in spirochete cultures. Pectin- or polygalacturonate-degrading hydrolases were not detected. A cell-associated lyase activity that catalyzed polygalacturonate breakdown was present in one of the spirochete strains. In addition to pectin, the isolates utilized polygalacturonic, glucuronic, or galacturonic acid as fermentable substrate but did not neutral sugars, amino acids, or other substrates tested. Although the oral spirochetes did not ferment hyaluronic acid, one of the strains grew in coculture with a hyaluronidase-producing Peptostreptococcus strain in a medium containing hyaluronic acid as fermentable substrate. Two of the isolates were identified as Treponema pectinovorum strains on the basis of their substrate utilization pattern, end products of fermentation, other phenotypic characteristics, and the guanine-plus-cytosine content of their DNA. Even though the pectinolytic isolates were specialized with respect to the fermentable substrates they utilized, they appeared to compete successfully with other microorganisms in their habitat.
Bacteriophage that can distinguish between wild-type Rhizobium japonicum and a non-nodulating mutant
Authors: Stacey G , Pocratsky L A , Puvanesarajah V
Published: January 2020

A bacteriophage (phage TN1) that lyses Rhizobium japonicum 3I1b110 was isolated from Tennessee soil. Structurally, this phage resembles the Escherichia coli phage T4, having an icosahedral head (47 by 60 nm) and a contractile tail (17 by 80 nm). An interesting feature of this phage is that it lyses all of the symbiotic defective mutants derived from R. japonicum 3I1b110 that were tested, except one, mutant strain HS123. Mutant strain HS123 is a non-nodulating mutant that is defective in attachment to soybean roots. Since Rhizobium attachment to host roots is thought to be mediated by a specific cell surface interaction, it is likely that mutant strain HS123 is defective in some way in its cell surface. Mutant strain HS123 bound soybean lectin to the same extent as the wild type as measured by the binding of tritium-labeled lectin. Phage TN1 did not attach to the surface of strain HS123, nor did cells of strain HS123 inactivate phage TN1. A hot phenol-water cell extract from the wild-type inactivated phage TN1, whereas a similar cell extract from mutant HS123 did not. Capsular polysaccharide isolated from mutant or wild type did not inactivate the phage. Capsular polysaccharide and exopolysaccharide from the mutant and wild type do not differ in sugar composition. These results indicate that capsular polysaccharide may not play a role in attachment to the plant root surface and that other cell wall components may be important.
Rapidly growing rumen methanogenic organism that synthesizes coenzyme M and has a high affinity for formate
Authors: Lovley D R , Greening R C , Ferry J G
Published: January 2020

Methanogenic bacteria with a coccobacillus morphology similar to Methanobrevibacter ruminantium were isolated from the bovine rumen. One isolate, 10-16B, represented a previously undescribed rumen population that, unlike M. ruminantium, synthesized coenzyme M, grew rapidly (mu = 0.24 h-1) on H2-CO2 in a complex medium, had simple nutritional requirements, and metabolized formate at reported rumen concentrations. H2 was metabolized to partial pressures 10-fold lower than those reported for the rumen. After H2 starvation for 26 h, strain 10-16B rapidly resumed growth when H2 was made available. The minimum concentrations of acetate (6 mM) and ammonia (less than 7 mM) that were required for optimal growth were lower than the reported acetate and ammonia concentrations in the rumen. Isoleucine and leucine stimulated growth, but only at concentrations (greater than 50 microM) higher than those reported for the rumen. Another coccobacillary methanogenic organism that synthesized coenzyme M was isolated from a different animal as were organisms that required an exogenous supply of coenzyme M. In general, methanogenic bacteria that required an exogenous supply of coenzyme M had lower maximum growth rates and more complex nutritional requirements than organisms that synthesized the cofactor. The ability of all isolates to metabolize formate below the detection limit of 10 microM indicated that, in contrast to previous reports, methanogenic bacteria have the potential to directly metabolize formate in the rumen. This study demonstrated that there are physiologically diverse populations of coccobacillary methanogenic bacteria in the rumen that can interact competitively and cooperatively.
Nitrogen Fixation and Carbon Dioxide Assimilation in
Rhizobium japonicum
Authors: Manian Sundaram S. , Gumbleton Robert , Buckley Anne M. , O'Gara Fergal
Published: January 2020

In free-living
Rhizobium japonicum
cultures, the stimulatory effect of CO
2
on nitrogenase (acetylene reduction) activity was mediated through ribulose bisphosphate carboxylase activity. Two mutant strains (CJ5 and CJ6) of
R. japonicum
defective in CO
2
fixation were isolated by mitomycin C treatment. No ribulose bisphosphate carboxylase activity could be detected in strain CJ6, but a low level of enzyme activity was present in strain CJ5. Mutant strain CJ5 also exhibited pleiotropic effects on carbon metabolism. The mutant strains possessed reduced levels of hydrogen uptake, formate dehydrogenase, and phosphoribulokinase activities, which indicated a regulatory relationship between these enzymes. The CO
2
-dependent stimulation of nitrogenase activity was not observed in the mutant strains. Both mutant strains nodulated soybean plants and fixed nitrogen at rates comparable to that of the wild-type strain.
Microbial models of mammalian metabolism: microbial reduction and oxidation of pentoxifylline
Authors: Davis P J , Yang S K , Smith R V
Published: January 2020

Fourteen microorganisms, including fungi, yeasts, and bacteria, were screened for their ability to metabolize the xanthine drug pentoxifylline. Thirteen cultures either reduced the drug to the alcohol metabolite or oxidatively cleaved the ketonic side chain to homologous carboxylic acid metabolites. The alcohol metabolite was the predominant or sole metabolite in all organisms, with conversions ranging from 6 to 91%. Preparative-scale production of the alcohol metabolite with Rhodotorula rubra (ATCC 20129) allowed for the isolation of this product with a 40% yield. Two organisms also produced the carboxylic acid metabolites at low levels (2 to 10%). The routes of metabolism in microbial cultures are the same as those reported in mammalian systems.
Transformation of Streptococcus sanguis Challis with Streptococcus lactis plasmid DNA
Authors: Harlander S K , McKay L L
Published: January 2020

Streptococcus lactis plasmid DNA, which is required for the fermentation of lactose (plasmid pLM2001), and a potential streptococcal cloning vector plasmid (pDB101) which confers resistance to erythromycin were evaluated by transformation into Streptococcus sanguis Challis. Plasmid pLM2001 transformed lactose-negative (Lac-) mutants of S. sanguis with high efficiency and was capable of conferring lactose-metabolizing ability to a mutant deficient in Enzyme IIlac, Factor IIIlac, and phospho-beta-galactosidase of the lactose phosphoenolpyruvate-phosphotransferase system. Plasmid pDB101 was capable of high-efficiency transformation of S. sanguis to antibiotic resistance, and the plasmid could be readily isolated from transformed strains. However, when 20 pLM2001 Lac+ transformants were analyzed by a variety of techniques for the presence of plasmids, none could be detected. In addition, attempts to cure the Lac+ transformants by treatment with acriflavin were unsuccessful. Polyacrylamide gel electrophoresis was used to demonstrate that the transformants had acquired a phospho-beta-galactosidase characteristic of that normally produced by S. lactis and not S. sanguis. It is proposed that the genes required for lactose fermentation may have become stabilized in the transformants due to their integration into the host chromosome. The efficient transformation into and expression of pLM2001 and pDB101 genes in S. sanguis provides a model system which could allow the development of a system for cloning genes from dairy starter cultures into S. sanguis to examine factors affecting their expression and regulation.
Role of resistance to starvation in bacterial survival in sewage and lake water
Authors: Sinclair J L , Alexander M
Published: January 2020

A study was conducted to determine the significance of starvation resistance to the ability of a species to survive in sewage and lake water. Tests were conducted for periods of up to 14 days. Rhizobium meliloti and one fluorescent and one nonfluorescent strain of Pseudomonas were resistant to starvation because their population sizes did not fall appreciably in buffer and sterile lake water, and the first two maintained high numbers after being added to sterile sewage. Cell densities of these bacterial species dropped slowly in nonsterile sewage, and more cells of these three organisms than of the other test organisms remained in nonsterile lake water. Rhizobium leguminosarum was moderately resistant to starvation because its numbers fell slowly in buffer and sterile lake water and did not change appreciably in sterile sewage. The abundance of Micrococcus flavus added to buffer and sterile lake water did not change, but the density of M. flavus declined in nonsterile lake water. The abundance of R. leguminosarum fell in nonsterile lake water and nonsterile sewage. Streptococcus faecalis, Staphylococcus aureus, an asporogenous strain of Bacillus subtilis, and Streptococcus sp. were susceptible to starvation because their populations were markedly reduced in buffer. Populations of the last three species declined rapidly in nonsterile and sterile samples of lake water and sewage. S. faecalis declined rapidly when added to nonsterile lake water and sewage and sterile lake water but not when added to sterile sewage, the persistence in the last instance probably being associated with the availability of organic nutrients.(ABSTRACT TRUNCATED AT 250 WORDS)
Improved bacterial recovery by membrane filters in the presence of food debris
Authors: Farber J M , Sharpe A N
Published: January 2020

In the absence of food debris, m-FC agar counts of Escherichia coli on Oxoid Nuflow membrane filters (Oxoid Canada Inc., Nepean, Ontario, Canada) were lower than the corresponding surface plate counts. For seven food types tested, recovery of E. coli improved with increasing thickness of food debris on the membrane filter, and mats thicker than 0.5 micron protected the organism completely.
Role of Ferrous Ions in Synthetic Cobaltous Sulfide Leaching of
Thiobacillus ferrooxidans
Authors: Sugio Tsuyoshi , Domatsu Chitoshi , Tano Tatsuo , Imai Kazutami
Published: January 2020

Microbiological leaching of synthetic cobaltous sulfide (CoS) was investigated with a pure strain of
Thiobacillus ferroxidans.
The strain could not grow on CoS-salts medium in the absence of ferrous ions (Fe
2+
). However, in CoS-salts medium supplemented with 18 mM Fe
2+
, the strain utilized both Fe
2+
and the sulfur moiety in CoS for growth, resulting in an enhanced solubilization of Co
2+
. Cell growth on sulfur-salts medium was strongly inhibited by Co
2+
, and this inhibition was completely protected by Fe
2+
. Cobalt-resistant cells, obtained by subculturing the strain in medium supplemented with both Fe
2+
and Co
2+
, brought a marked decrease in the amount of Fe
2+
absolutely required for cell growth on CoS-salts medium. As one mechanism of protection by Fe
2+
, it is proposed that the strain utilizes one part of Fe
2+
externally added to CoS-salts medium to synthesize the cobalt-resistant system. Since a similar protective effect by Fe
2+
was also observed for cell inhibition by stannous, nickel, zinc, silver, and mercuric ions, a new role of Fe
2+
in bacterial leaching in
T. ferrooxidans
is proposed.
Effect of proteins on reovirus adsorption to clay minerals
Authors: Lipson S M , Stotzky G
Published: January 2020

Organic matter in sewage, soil, and aquatic systems may enhance or inhibit the infectivity of viruses associated with particulates (e.g., clay minerals, sediments). The purpose of this investigation was to identify the mechanisms whereby organic matter, in the form of defined proteins, affects the adsorption of reovirus to the clay minerals kaolinite and montmorillonite and its subsequent infectivity. Chymotrypsin and ovalbumin reduced the adsorption of reovirus to kaolinite and montmorillonite homoionic to sodium. Lysozyme did not reduce the adsorption of the virus to kaolinite, but it did reduce adsorption to montmorillonite. The proteins apparently competed with the reovirus for sites on the clay. As lysozyme does not adsorb to kaolinite by cation exchange, it did not inhibit the adsorption of reovirus to this clay. The amount of reovirus desorbed from lysozyme-coated montmorillonite was approximately 38% less (compared with the input population) than that from uncoated or chymotrypsin-coated montmorillonite after six washings with sterile distilled water. Chymotrypsin and lysozyme markedly decreased reovirus infectivity in distilled water, whereas infectivity of the virus was enhanced after recovery from an ovalbumin-distilled water-reovirus suspension (i.e., from the immiscible pelleted fraction plus supernatant). The results of these studies indicate that the persistence of reovirus in terrestrial and aquatic environments may vary with the type of organic matter and clay mineral with which the virus comes in contact.