bluuebunny/crossref_metadata_2025 huggingface dataset:
Production of Coenzyme A by a Mutant of
Brevibacterium ammoniagenes
Resistant to Oxypantetheine
Authors: Shimizu Sakayu , Esumi Akihiko , Komaki Ryohei , Yamada Hideaki
Published: January 2020

For improved production of coenzyme A (CoA), a mutant of
Brevibacterium ammoniagenes
IFO127071 resistant to oxypantetheine, the corresponding oxygen analog of pantetheine, was obtained. In the mutant, activity of pantothenate kinase (EC 2.7.1.33), the first-step enzyme for the biosynthesis of CoA from pantothenic acid,
l
-cysteine, and ATP, was about threefold higher than that in the parent strain. As the main regulation mechanism of CoA biosynthesis in this bacterium is negative feedback inhibition of pantothenate kinase by CoA, the mutant is very useful as a catalyst for practical production of CoA. When added to culture broth of the mutant, pantothenate,
l
-cysteine, and AMP gave 9.3 mg of CoA per ml. With pantetheine and AMP, 11.5 mg of CoA per ml accumulated. These values were about threefold higher than those with the parent strain, and more than 70% of the added AMP was converted to CoA.
Measurement and Study of Substrate Specificity of Exoglucosidase Activity in Eutrophic Water
Authors: Somville Martine
Published: January 2020

The α- and β-glucosidase activity in natural samples can be readily measured during short incubation times (20 min) by using the artificial substrates 4-methylumbelliferyl-α-
d
-glucoside and 4-methylumbelliferyl-β-
d
-glucoside. The apparent
K

m

of both α- and β-glucosidase for these respective substrates is 0.01 μM. The homologous disaccharides maltose and cellobiose competitively inhibit α- and β-glucosidase, respectively. Absolute substrate specificity of the α- and β-glucosidase is observed with respect to the configuration of carbon atoms 1 and 4. Enrichment cultures on either α- and β-glucoside result in increasing activity of the corresponding glucosidase, both in absolute terms and with respect to the other glucosidase.
Degassing of Pore Water Methane during Sediment Incubations
Authors: Kiene Ronald P. , Capone Douglas G.
Published: January 2020

Laboratory experiments were used to examine the degassing of CH
4
from a muddy sediment. Sediment containing dissolved CH
4
showed a hyperbolic time course of CH
4
release when allowed to degas in stoppered 20-ml vials. Equilibration required ca. 24 h for 5 ml of sediment. The rate of CH
4
release was found to be dependent on the ratio of exposed sediment surface area to sediment volume. The water content of the sediment was a factor in the total amount of CH
4
released but did not affect the rate of degassing. Addition of water to sediment samples (to form a slurry) accelerated CH
4
release, with a 1:1 dilution giving ca. 80% of maximum release after only 2 min. Shaking (vortexing) the sediments also facilitated CH
4
exchange, with 2 min of vigorous agitation giving 77% of maximum release. The organic content of the sediment did not affect either the amount or the rate of CH
4
degassing. Rubber stoppers exposed to CH
4
were found to absorb CH
4
rapidly and to subsequently release it in proportion to the concentration to which they were exposed. Artifacts may be associated with CH
4
production measurements if sediment and stopper degassing are not considered. It is recommended that any study of methane production or distribution include preliminary experiments to determine the degassing kinetics for the specific sediment system being used.
Incorporation of phenol carbon at trace concentrations by phenol-mineralizing microorganisms in fresh water
Authors: Chesney R H , Sollitti P , Rubin H E
Published: January 2020

The fate of phenol carbon at phenol concentrations ranging from 1 ng/ml to 1 microgram/ml was determined in freshwater samples. Approximately 20% of the parent phenol was incorporated into trichloroacetic acid-precipitable material by the microorganisms capable of mineralizing phenol. There was no apparent lag period before phenol incorporation commenced, and incorporation was complete within 2 h at all concentrations tested. A direct relationship was found between the initial phenol concentrations and both phenol mineralization and incorporation rates, indicating that cometabolism of phenol does not occur at concentrations that are environmentally significant. At all concentrations, approximately 80% of the initial phenol concentration was mineralized. This percentage plus the percentage of phenol incorporated at the various concentrations equaled approximately 100%. Therefore, the parent phenol does not remain in fresh water; it is either incorporated into cellular biomass or mineralized. However, the incorporated phenol carbon is subject to bioaccumulation in nature. There was no apparent lag period before thymidine was incorporated into biomass, and incorporation was complete within 4 to 8 h at all of the phenol concentrations tested. Thymidine incorporation was independent of phenol concentration at all levels tested. This is probably due to the small amount of thymidine incorporated by the phenol-mineralizing microorganisms in comparison with the amount of thymidine incorporated by the total microbial population.
Interaction between Streptococcus lactis and Aspergillus flavus on production of aflatoxin
Authors: Coallier-Ascah J , Idziak E S
Published: January 2020

The inoculation of Aspergillus flavus spores into a culture of Streptococcus lactis in Lablemco tryptone broth medium resulted in little or no aflatoxin accumulation even though the growth of the fungus was not hindered. The drop in pH and reduced nutrient levels in the medium as a result of the S. lactis growth were not the cause of the observed inhibition. The inhibition was not eliminated by the addition of carbohydrate equal to the amount used by the bacterium before the inoculation with the fungus. Aflatoxin levels were also markedly reduced when S. lactis was inoculated into a growing A. flavus culture. In addition to inhibiting the synthesis of aflatoxin, S. lactis also degraded preformed toxin. A. flavus, on the other hand, not only reduced the growth of S. lactis but also affected the morphology of the bacterial cell; the cells became elongated and formed long chains. S. lactis produced and excreted the inhibitor into the medium late in its growth phase. The inhibitor was a heat-stable low-molecular-weight compound. Chloroform extracts of A. flavus grown in the presence of S. lactis were toxic to Bacillus megaterium but did not exhibit mutagenic or carcinogenic activity in the Salmonella/mammalian microsome mutagenicity test.
Degradation of Dehydrodivanillin by Anaerobic Bacteria from Cow Rumen Fluid
Authors: Chen Wei , Ohmiya Kunio , Shimizu Shoichi , Kawakami Hidekuni
Published: January 2020

Dehydrodivanillin (DDV; 0.15 g/liter) was biodegradable at 37°C under strictly anaerobic conditions by microflora from cow rumen fluid to the extent of 25% within 2 days in a yeast extract medium. The anaerobes were acclimated on DDV for 2 weeks, leading to DDV-degrading microflora with rates of degradation eight times higher than those initially. Dehydrodivanillic acid and vanillic acid were detected in an ethylacetate extract of a DDV-enriched culture broth by thin-layer, gas, and high-performance liquid chromatographies and by mass spectrometry.
Ecology of Legionella pneumophila within water distribution systems
Authors: Stout J E , Yu V L , Best M G
Published: January 2020

The reservoir for hospital-acquired Legionnaires disease has been shown to be the potable water distribution system. We investigated the influence of the natural microbial population and sediment (scale and organic particulates) found in water systems as growth-promoting factors for Legionella pneumophila. Our in vitro experiments showed that: (i) water from hot-water storage tank readily supported the survival of L. pneumophila, (ii) the concentration of sediment was directly related to the survival of L. pneumophila, (iii) the presence of environmental bacteria improved the survival of L. pneumophila via nutritional symbiosis, (iv) the combination of sediment and environmental bacteria acted synergistically to improve the survival of L. pneumophila, and (v) the role of sediment in this synergistic effect was determined to be nutritional. Sediment was found to stimulate the growth of environmental microflora, which in turn stimulated the growth of L. pneumophila. These findings confirm the empiric observations of the predilection of L. pneumophila for growth in hot-water tanks and its localization to sediment. L. pneumophila occupies an ecological niche within the potable water system, with interrelationships between microflora, sediment, and temperature.
Control of Oxidative Sulfur Metabolism of
Chlorobium limicola
forma
thiosulfatophilum
Authors: Cork Douglas , Mathers Jeremy , Maka Andrea , Srnak Anna
Published: January 2020

A metered blend of anaerobic-grade N
2
, CO
2
, and H
2
S gases was introduced into an illuminated, 800-ml liquid volume, continuously stirred tank reactor. The system, described as an anaerobic gas-to-liquid phase fed-batch reactor, was used to investigate the effects of H
2
S flow rate and light energy on the accumulation of oxidized sulfur compounds formed by the photoautotroph
Chlorobium limicola
forma
thiosulfatophilum
during growth. Elemental sulfur was formed and accumulated in stoichiometric quantities when light energy and H
2
S molar flow rate levels were optimally adjusted in the presence of nonlimiting CO
2
. Deviation from the optimal H
2
S and light energy levels resulted in either oxidation of sulfur or complete inhibition of sulfide oxidation. Based on these observations, a model of sulfide and sulfur oxidases electrochemically coupled to the photosynthetic reaction center of
Chlorobium
spp. is presented. The dynamic deregulation of oxidative pathways may be a mechanism for supplying the photosynthetic reaction center with a continuous source of electrons during periods of varying light and substrate availability, as in pond ecosystems where
Chlorobium
spp. are found. Possible applications for a sulfide gas removal process are discussed.
Factors Involved in the Regulation of a Ligninase Activity in
Phanerochaete chrysosporium
Authors: Faison B. D. , Kirk T. K.
Published: January 2020

The regulation of an H
2
O
2
-dependent ligninolytic activity was examined in the wood decay fungus
Phanerochaete chrysosporium.
The ligninase appears in cultures upon limitation for nitrogen or carbohydrate and is suppressed by excess nutrients, by cycloheximide, or by culture agitation. Activity is increased by idiophasic exposure of cultures to 100% O
2
. Elevated levels of ligninase and, in some cases, of extracellular H
2
O
2
production are detected after brief incubation of cultures with lignins or lignin substructure models, with the secondary metabolite veratryl alcohol, or with other related compounds. It is concluded that lignin degradation (lignin → CO
2
) by this organism is regulated in part at the level of the ligninase, which is apparently inducible by its substrates or their degradation products.
Legionella anisa: a new species of Legionella isolated from potable waters and a cooling tower
Authors: Gorman G W , Feeley J C , Steigerwalt A , Edelstein P H , Moss C W , Brenner D J
Published: January 2020

Between March 1980 and June 1981, five strains of Legionella-like organisms were isolated from water. Four were recovered from potable water collected from hospitals in Chicago, Ill., and Los Angeles, Calif., during outbreaks of nosocomial legionellosis. The fifth strain was isolated from water collected from an industrial cooling tower in Jamestown, N.Y. The strains exhibited biochemical reactions typical of Legionella species and were gram-negative motile rods which grew on buffered charcoal-yeast extract agar but not on blood agar, required cysteine, and were catalase positive, urease negative, nitrate negative, hippurate negative, and nonfermentative. All strains were positive for oxidase and beta-lactamase and produced a brown, diffusible pigment. Of the five strains, four exhibited blue-white autofluorescence under long-wavelength UV light. The fatty-acid composition and ubiquinone content of these strains were consistent with those of other Legionella species. Direct fluorescent-antibody examination of the five strains with conjugates to previously described Legionella species demonstrated no cross-reactions except with the conjugates to L. longbeachae serogroup 2 and L. bozemanii serogroup 2. Four strains gave a 4+ reaction to the L. longbeachae serogroup 2 conjugate and the fifth strain gave a 1+ reaction. Each of the five strains gave a 4+ reaction with the conjugate to L. bozemanii serogroup 2. DNAs from the five strains were highly related (84 to 99%) and showed 5 to 57% relatedness to other Legionella species. These strains constitute a new species in the genus Legionella, and the name Legionella anisa sp. nov. is proposed. The type strain of L. anisa is WA-316-C3 (ATCC 35292).
Flocculation Effects on Bound Water in Sludges as Measured by Nuclear Magnetic Resonance Spectroscopy
Authors: Carberry Judith Bower , Prestowitz Robert A.
Published: January 2020

Nuclear magnetic resonance relaxation times (
T
1
and
T
2
) were measured for flocculated and unflocculated samples of activated sludge. The weight of water and solids in the sludge samples was found and related to
T
1
to find the relative percentage of bound water. The results suggest that the amount of bound water increases as the samples become more unflocculated. The values of
T
1
and
T
2
also indicate that unflocculated individual particles are characterized by loose packing of shorter molecules and that the addition of larger molecules may induce flocculation.
Antimicrobial activities of N-chloramines and diazolidinyl urea
Authors: Llabres C M , Ahearn D G
Published: January 2020

A combination of MICs of an N-chloramine, a simple chlorinated amino acid, and diazolidinyl urea gave synergistic activity against bacteria, but not fungi. The two compounds at a higher concentration, 0.1 and 0.3%, respectively, gave synergistic inhibition of fungi; kill times were 1 h for Trichophyton tonsurans, 3 h for Aspergillus niger and Fusarium moniliforme, and 6 h for Aspergillus fumigatus.
Assimilation of cholesterol by Lactobacillus acidophilus
Authors: Gilliland S E , Nelson C R , Maxwell C
Published: January 2020

Considerable variation was found among strains of Lactobacillus acidophilus isolated from the fecal flora of pigs with regard to the ability to grow well in the presence of bile and to assimilate cholesterol from a laboratory growth medium. The uptake of cholesterol occurred only when the culture(s) was growing in the presence of bile under anaerobic conditions. Consumption of L. acidophilus RP32, which was selected for its ability to grow well in the presence of bile and to assimilate cholesterol from the laboratory medium, significantly inhibited increases in serum cholesterol levels of pigs (P less than 0.05) fed a high-cholesterol diet. Consumption of L. acidophilus P47, which was selected for its ability to grow in the presence of bile and lack of ability to remove cholesterol from the growth medium, failed to have a similar effect. This indicates that certain strains of L. acidophilus act directly on cholesterol in the gastrointestinal tract, and thus may be beneficial in reducing serum cholesterol levels.
Quantitative studies of heat-stable proteinase from Pseudomonas fluorescens P1 by the enzyme-linked immunosorbent assay
Authors: Birkeland S E , Stepaniak L , Sørhaug T
Published: January 2020

Pseudomonas fluorescens P1 is a psychrotrophic bacterium isolated from milk. Proteinase P1, the main extracellular heat-stable proteinase fraction of P. fluorescens P1, has been purified to homogeneity. A procedure with a sandwich enzyme-linked immunosorbent assay, using microplates and alkaline phosphatase conjugate was shown to detect 0.25 ng of proteinase P1 in 1 ml of reconstituted skim milk or defatted cream. The method offers the combination of sensitivity and specificity for the detection of these enzymes in milk and dairy products. In reconstituted skim milk cultures proteinase P1 was detectable when the CFU approached 10(7)/ml. Cultures in milk diluted 1:10, 1:30, or 1:100 with water showed detectable proteinase at population densities close to 10(6) CFU/ml. Aeration stimulated proteinase production; thus, a skim milk culture with shaking at 5 degrees C had a proteinase level of 36,000 ng/ml after 7 days as compared to 80 ng/ml in a stationary culture. The rate of inactivation of proteinase P1 at 150 and 55 degrees C as expressed by residual antigenic activity determined by the enzyme-linked immunosorbent assay was somewhat different from the rate determined on the basis of residual proteolytic activity. The specificity of the enzyme-linked immunosorbent assay with proteinase P1 antibodies was identical for proteinase P1 and for enzymes from six other strains of P. fluorescens, one Chromobacterium strain, and one Flavobacterium strain. Some psychrotrophic strains produced immunologically unrelated proteinase(s). These preliminary observations indicate that proteinase P1-related enzymes are common among psychrotrophs appearing as spoilage bacteria in milk.
Influence of Naturally Occurring Humic Acids on Biodegradation of Monosubstituted Phenols by Aquatic Bacteria
Authors: Shimp Robert , Pfaender Frederic K.
Published: January 2020

Samples of the microbial community from Lake Michie, a mesotrophic reservoir in central North Carolina, were adapted to various levels (100 to 1,000 μg/liter) of natural humic acids in chemostats. The humic acids were extracted from water samples from Black Lake, a highly colored lake in the coastal plain of North Carolina. After adaptation, the microbial community was tested for its ability to degrade the monosubstituted phenols
m
-cresol,
m
-aminophenol, and
p
-chlorophenol. Adaptation to increasing levels of humic acids significantly reduced the ability of the microbial communities to degrade all three phenols. The decline in biodegradation was accompanied by a decrease in the number of specific compound degraders in the adapted communities. Short-term exposure of the community to increasing levels of humic acids had no significant effect on the ability of the community to degrade
m
-cresol. Thus the suppressive effect of humic acids on monosubstituted phenol metabolism was the result of long-term exposure to the humic materials. Increasing the levels of inorganic nutrients fed to the chemostats during the humic acid adaptation had little effect on the suppressive influence of the humic acids, indicating that nutrient limitation was probably not responsible for the metabolic suppression. The results of the study suggest that long-term exposure to humic acids can reduce the ability of microbial communities to respond to monosubstituted phenols.
Straw and Xylan Utilization by Pure Cultures of Nitrogen-Fixing
Azospirillum
spp
Authors: Halsall Dorothy M. , Turner Graham L. , Gibson Alan H.
Published: January 2020

Azospirillum
spp. were shown to utilize both straw and xylan, a major component of straw, for growth with an adequate combined N supply and also under N-limiting conditions. For most strains examined, a semisolid agar medium was satisfactory, but several strains appeared to be capable of slow metabolism of the agar. Subsequently, experiments were done with acid-washed sand supplemented with various carbon sources. In these experiments, authenticated laboratory strains, and all 16 recent field isolates from straw-amended soils, of both
A. brasilense
and
A. lipoferum
possessed the ability to utilize straw and xylan as energy sources for nitrogen fixation. Neither carboxymethyl cellulose nor cellulose was utilized. The strains and isolates differed in their abilities to utilize xylan and straw and in the efficiency of nitrogenase activity (CO
2
/C
2
H
2
ratio). Reasonable levels of activity could be maintained for at least 14 days in the sand cultures. Nitrogenase activity (acetylene reduction) was confirmed by
15
N
2
incorporation. The level of nitrogenase activity observed was dependent on the time of the addition of acetylene to the culture vessels.
Degradation of the Herbicide Mecoprop [2-(2-Methyl-4-Chlorophenoxy)Propionic Acid] by a Synergistic Microbial Community
Authors: Lappin Hilary M. , Greaves Michael P. , Slater J. Howard
Published: January 2020

A microbial community isolated from wheat root systems was capable of growth on mecoprop as the sole carbon and energy source. When exposed to fresh herbicide additions, the community was able to shorten the lag phase from 30 days to less than 24 h. The community comprised two
Pseudomonas
species, an
Alcaligenes
species, a
Flavobacterium
species, and
Acinetobacter calcoaceticus
. None of the pure cultures was capable of growing on mecoprop. Certain combinations of two or more community constituents were required before growth commenced. The mecoprop-degrading community could also degrade 2,4-dichlorophenoxyacetic acid and 2-methyl-4-chlorophenoxyacetic acid but not 2,4,5-trichlorophenoxyacetic acid.
Decomposition of [
14
C]Lignocelluloses of
Spartina alterniflora
and a Comparison with Field Experiments
Authors: Wilson John O.
Published: January 2020

Decomposition of lignocelluloses from
Spartina alterniflora
in salt-marsh sediments was measured by using
14
C-labeled compounds. Rates of decomposition were fastest in the first 4 days of incubation and declined later. Lignins labeled in side chains were mineralized slightly faster than uniformly labeled lignins; 12% of the [side chain-
14
C]lignin-labeled lignocellulose was mineralized after 816 h of incubation, whereas only 8% of the [U-
14
C]lignin-labeled lignocelluloses were degraded during this period. The carbohydrate moiety within the lignocellulose complex was degraded about four times faster than the lignin moiety; after 816 h of incubation, 29 to 37% of the carbohydrate moiety had been mineralized. Changes in concentration of lignin and cellulose in litter of
S. alterniflora
were followed over 2 years of decay. Cellulose disappeared from litter more rapidly than lignin; 50% of the initial content of cellulose was lost after 130 days, whereas lignin required 330 to 380 days for 50% loss. The slow loss of lignin compared with other litter components resulted in a progressive enrichment of litter in lignin content. The rates of mineralization of [
14
C]lignocelluloses in marsh sediments were similar to the rates of lignocellulose decomposition in litter on the marsh.
Primary and Bacterial Production in Two Dimictic Indiana Lakes
Authors: Lovell Charles R. , Konopka Allan
Published: January 2020

The relationship between primary and bacterial production in two dimictic Indiana lakes with different primary productivities was examined during the summer stratification period in 1982. Primary production rates were calculated from rates of H
14
CO
3
−
incorporation by natural samples, and bacterial production was calculated from rates of [
3
H-
methyl
]thymidine incorporation by natural samples. Both vertical and seasonal distributions of bacterial production in the more productive lake (Little Crooked Lake) were strongly influenced by primary production. A lag of about 2 weeks between a burst in primary production and the subsequent response in bacterial production was observed. The vertical distribution of bacterial production in the water column of the less productive lake (Crooked Lake) was determined by the vertical distribution of primary production, but no clear relationship between seasonal maxima of primary and bacterial production in this lake was observed. High rates of bacterial production in Crooked Lake during May indicate the importance of allochthonous carbon washed in by spring rains. Bacterial production accounted for 30.6 and 31.8% of total (primary plus bacterial) production in Crooked Lake and Little Crooked Lake, respectively, from April through October. High rates of bacterial production during late September and October were observed in both lakes. Calculation of the fraction of bacterial production supported by phytoplankton excretion implies an important role for other mechanisms of supplying carbon, such as phytoplankton autolysis. Several factors affecting the calculation of bacterial production from the thymidine incorporation rates in these lakes were examined.
Occurrence of Zearalenols (Diastereomeric Mixture) in Corn Stalk Rot and Their Production by Associated
Fusarium
Species
Authors: Bottalico Antonio , Visconti Angelo , Logrieco Antonio , Solfrizzo Michele , Mirocha Chester J.
Published: January 2020

Zearalenol was extracted from
Fusarium
-infected stems of corn from southern Italy. The toxin, which appeared as a single compound in various thin-layer chromatography systems, was resolved by high-pressure liquid chromatography into two components. A gas chromatography-mass spectrometry examination of a purified fraction confirmed the natural occurrence of zearalenol as a diastereomeric mixture and led to the identification of alpha (56 ng/g) and beta (27 ng/g) isomers. Among nine
Fusarium
species found associated with stalk rot in corn, only
Fusarium culmorum (F. roseum
`Culmorum') and
F. equiseti (F. roseum
`Gibbosum') produced zearalenol and always produced it in a diastereomeric mixture of alpha and beta isomers.
Methanosarcina mazei
LYC, a New Methanogenic Isolate Which Produces a Disaggregating Enzyme
Authors: Liu Yitai , Boone David R. , Sleat Robert , Mah Robert A.
Published: January 2020

A methanogenic coccoid organism,
Methanosarcina mazei
LYC, was isolated from alkaline sediment obtained from an oil exploration drilling site. The isolate resembled
M. mazei
S-6 by exhibiting different morphophases during its normal growth cycle. It differed from
M. mazei
S-6 by undergoint a spontaneous shift from large, irregular aggregates of cells to small, individual, irregular, coccoid units. In batch cultures at pH 7.0,
M. mazei
LYC grew as aggregates during the early growth stage. As the batch culture began exponential growth, the cell aggregates spontaneously dispersed: the culture liquid became turbid, and myriads of tiny (diameter, 1 to 3 μm) coccoid units were observed under phase-contrast microscopy. Disaggregation apparently was accomplished by the production of an enzyme which hydrolyzed the heteropolysaccharide component of the cell wall; the enzyme was active on other
Methanosarcina
strains as well. Although the enzyme was active when tested at pH 6.0, it apparently was not produced at that pH: when strain LYC was grown at pH 6.0, only cell aggregates were present throughout batch growth. Individual coccoid cells of
M. mazei
LYC were sensitive to sodium dodecyl sulfate, but the large aggregates of cells were not. Strain LYC rapidly used H
2
-CO
2
, in addition to methanol, and mono-, di-, and trimethylamine as methanogenic substrates; acetate was used very slowly. Its optimum growth temperature was 40°C, and its optimum pH was 7.2.
Bovine serum eliminates rapid nonspecific toxic reactions during bioassay of stored fish for Clostridium botulinum toxin
Authors: Solberg M , Post L S , Furgang D , Graham C
Published: January 2020

When stored fish or some fish products were tested for the presence of Clostridium botulinum toxin, nonspecific toxic reactions in mice often occurred, rendering the bioassay inconclusive. The nonspecific toxic reactions were mediated by the gram-negative microbiota, inherent to the fish, which were the source of lethal, heat-stable endotoxins. The treatment of assay samples with bovine serum eliminated nonspecific reactions through the interaction of constituent serum immunoglobulin M (IgM) with endotoxic material. Removal of IgM from bovine serum through treatment with protein A or concanavalin A resulted in a loss of protective activity.
Macrocyclic trichothecene toxins produced by Stachybotrys atra strains isolated in Middle Europe
Authors: Bata A , Harrach B , Ujszászi K , Kis-Tamás A , Lásztity R
Published: January 2020

A total of 17 strains of Stachybotrys atra isolated in Hungary and Czechoslovakia were cultured on Sabouraud agar, and the toxins produced by them were chemically analyzed by gas-liquid chromatography, high-pressure liquid chromatography, and mass spectroscopy. Furthermore, brine shrimp (Artemia salina) bioassay was used for the determination of toxicity of the compounds examined. Macrocyclic trichothecenes (satratoxins H and G, roridin E, and verrucarin J as well as two other unidentified macrocyclic trichothecenes) were found in all of the cultures tested. The identities of satratoxins H and G, roridin E, and verrucarin J were qualitatively determined by high-pressure liquid chromatography and gas-liquid chromatography. The ratio of satratoxins H and G and roridin E was found to be similar in each of the strains tested, but the amount of verrucarin J found was different in each of them. One of the unidentified macrocyclic trichothecenes was equivalent to the compound isolated by Harrach et al. (Harrach et al., Appl. Environ. Microbiol. 41:1428-1433, 1981). The other one proved to be a newly isolated macrocyclic trichothecene toxin. Stachybotryotoxicosis, one of the oldest mycotoxicoses known, and a serious problem in Middle Europe (Gy. Danko, Magy. Allatorv. Lapja 31:226-232, 1976), is believed to be caused by macrocyclic trichothecene toxins produced by Stachybotrys atra (R. M. Eppley, in Rodricks et al., ed., Mycotoxins in Human and Animal Health, p. 285-293, 1977). Forty years ago, the death of animals in the Soviet Union was associated with this fungus (C. U. Ruhliada, in Proceedings of the All-Union Sci. and Tech. Conf., p. 47-51, 1980).(ABSTRACT TRUNCATED AT 250 WORDS)
Preparation of a DNA gene probe for detection of mercury resistance genes in gram-negative bacterial communities
Authors: Barkay T , Fouts D L , Olson B H
Published: January 2020

A DNA gene probe was prepared to study genetic change mechanisms responsible for adaptation to mercury in natural bacterial communities. The probe was constructed from a 2.6-kilobase NcoI-EcoRI DNA restriction fragment which spans the majority of the mercury resistance operon (mer) in the R-factor R100. The range of specificity of this gene probe was defined by hybridization to the DNA of a wide variety of mercury-resistant bacteria previously shown to possess the mercuric reductase enzyme. All of the tested gram-negative bacteria had DNA sequences homologous to the mer probe, whereas no such homologies were detected in DNA of the gram-positive strains. Thus, the mer probe can be utilized to study gene flow processes in gram-negative bacterial communities.
Bacterial Fouling in a Model Core System
Authors: Shaw J. C. , Bramhill B. , Wardlaw N. C. , Costerton J. W.
Published: January 2020

We have used a sintered glass bead core to simulate the spaces and surfaces of reservoir rock in studies of the bacterial plugging phenomenon that affects waterflood oil recovery operations. The passage of pure or mixed natural populations of bacteria through this solid matrix was initially seen to promote the formation of adherent bacterial microcolonies on available surfaces. Bacteria within these microcolonies produced huge amounts of exopolysaccharides and coalesced to form a confluent plugging biofilm that eventually caused a >99% decrease in core permeability. Aerobic bacteria developed a plugging biofilm on the inlet face of the core, facultative anaerobes plugged throughout the core, and dead bacteria did not effectively plug the narrow (33-μm) spaces of this solid matrix because they neither adhered extensively to surfaces nor produced the extensive exopolysaccharides characteristic of living cells. The presence of particles in the water used in these experiments rapidly decreased the core permeability because they became trapped in the developing biofilm and accelerated the plugging of pore spaces. Once established, cells within the bacterial biofilm could be killed by treatment with a biocide (isothiazalone), but their essentially inert carbohydrate biofilm matrix persisted and continued to plug the pore spaces, whereas treatment with 5% sodium hypochlorite killed the bacteria, dissolved the exopolysaccharide biofilm matrix, and restored permeability to these plugged glass bead cores.
Influence of Calcium Addition on Growth of Highly Purified Syntrophic Cultures Degrading Long-Chain Fatty Acids
Authors: Roy Francis , Albagnac Guy , Samain Eric
Published: January 2020

Two highly purified syntrophic associations resulting in acetogenesis from stearate (SM) and oleate (OM) were obtained from the sludges of a sewage digestor. In both cases,
Methanospirillum hungatei
together with short, motile, gram-negative, nonfluorescent rods morphologically similar to
Syntrophomonas wolfei
were identified by microscopic examination. Besides growing on volatile fatty acids (butyrate through caproate), both cultures grew on oleate (C
18:1
) and numerous even-numbered, saturated long-chain fatty acids (LCFA [decanoate through stearate]). In addition, during growth on LCFA, supplementation of the culture media with calcium chloride was an absolute requirement. The sole difference between the associations was observed when SM and OM cultures were transferred from a stearate to an oleate medium. The SM culture needed 10 days before starting to degrade oleate, whereas the OM culture grew immediately, but the OM culture also grew immediately when transferred to stearate medium. Saturated LCFA degradation occurred in the presence of equinormal amounts of calcium (fatty acid/Ca ratio, 2). On the other hand, OM degradation only took place in the presence of an equimolar amount of calcium (fatty acid/Ca ratio, 1). These observations are discussed by considering the solubility constants of LCFA as calcium salts and the toxicity of the free acids against microorganisms.
Modification of the 14C most-probable-number method for use with nonpolar and volatile substrates
Authors: Somerville C C , Monti C A , Spain J C
Published: January 2020

A method was developed to allow the use of volatile and nonpolar substrates in 14C most-probable-number tests. Naphthalene or hexadecane was sorbed to filter paper disks and submerged in minimal medium. The procedure reduced the volatilization of the substrates while allowing them to remain available for microbial degradation.
Isolation of Noninhibitory Strains of
Zymomonas mobilis
Authors: Haffie Thomas L. , Louie Paul W. , Khachatourians George G.
Published: January 2020

Wild-type
Zymomonas mobilis
strains inhibit the growth of
Escherichia coli
. We report the first isolation of noninhibitory strains, called
Zymomonas
inhibition negative (Zin
−
), after treatment with
N
-methyl-
N
′-nitro-
N
-nitrosoguanidine. A standardized soft-agar overlay procedure for detecting
E. coli
growth inhibition was also developed.
Simplified Enzyme-Linked Immunosorbent Assay for Routine Identification of
Rhizobium japonicum
Antigens
Authors: Fuhrmann J. , Wollum A. G.
Published: January 2020

A simple, reliable, and flexible modification of the indirect enzyme-linked immunosorbent assay was developed for the identification of
Rhizobium japonicum
antigens from cultures and nodules. The procedure emphasizes efficient use of time and reagents, adaptability to variously equipped laboratories, and maintenance of sensitivity levels that are adequate for ecological studies.
Influence of pH on organic acid production by Clostridium sporogenes in test tube and fermentor cultures
Authors: Montville T J , Parris N , Conway L K
Published: January 2020

The influence of pH on the growth parameters of and the organic acids produced by Clostridium sporogenes 3121 cultured in test tubes and fermentors at 35 degrees C was examined. Specific growth rates in the fermentor maintained at a constant pH ranged from 0.20 h-1 at pH 5.00 to 0.86 h-1 at pH 6.50. Acetic acid was the primary organic acid in supernatants of 24-h cultures; total organic acid levels were 2.0 to 22.0 mumol/ml. Supernatants from pH 5.00 and 5.50 cultures had total organic acid levels less than one-third of those found at pH 6.00 to 7.00. The specific growth rates of the test tube cultures ranged from 0.51 h-1 at pH 5.00 to 0.95 h-1 at pH 6.50. The pH of the medium did not affect the average total organic acid content (51.5 mumol/ml) but did affect the distribution of the organic acids, which included formic, acetic, propionic, butyric, 3-(p-hydroxyphenyl)propionic, and 3-phenylpropionic acids. Butyric acid levels were lower, but formic and propionic acid levels were higher, at pH 5.00 than at other pHs.
Plasmid-borne Tn5 insertion mutation resulting in accumulation of gentisate from salicylate
Authors: Monticello D J , Bakker D , Schell M , Finnerty W R
Published: January 2020

Plasmid-borne Tn5 insertion mutants of a Pseudomonas species which accumulated 2,5-dihydroxybenzoate (gentisate) following growth on 2-hydroxybenzoate (salicylate) were obtained from a pool of mutants that were unable to grow on naphthalene. One such mutant was characterized further. The ability of this mutant to oxidize gentisate was 100-fold less than the ability of a Nah+ Sal+ strain harboring the unmutagenized plasmid, although both strains oxidized and grew on salicylate. These bacteria were presumably able to metabolize salicylate via catechol, since they possessed an inducible, plasmid-encoded catechol 2,3-dioxygenase. Our results suggest that there is an alternate, plasmid-encoded route of salicylate degradation via gentisate and that some plasmid-associated relationship between this pathway and naphthalene oxidation exists.
Detection, enumeration, and sizing of planktonic bacteria by image-analyzed epifluorescence microscopy
Authors: Sieracki M E , Johnson P W , Sieburth J M
Published: January 2020

Epifluorescence microscopy is now being widely used to characterize planktonic procaryote populations. The tedium and subjectivity of visual enumeration and sizing have been largely alleviated by our use of an image analysis system consisting of a modified Artek 810 image analyzer and an Olympus BHT-F epifluorescence microscope. This system digitizes the video image of autofluorescing or fluorochrome-stained cells in a microscope field. The digitized image can then be stored, edited, and analyzed for total count or individual cell size and shape parameters. Results can be printed as raw data, statistical summaries, or histograms. By using a stain concentration of 5 micrograms of 4'6-diamidino-2-phenylindole per ml of sample and the optimal sensitivity level and mode, counts by image analysis of natural bacterial populations from a variety of habitats were found to be statistically equal to standard visual counts. Although the time required to prepare slides, focus, and change fields is the same for visual and image analysis methods, the time and effort required for counting is eliminated since image analysis is instantaneous. The system has been satisfactorily tested at sea. Histograms of cell silhouette areas indicate that rapid and accurate estimates of bacterial biovolume and biomass will be possible with this system.
Enumeration and activity of cellulolytic bacteria from gestating swine fed various levels of dietary fiber
Authors: Varel V H , Pond W G
Published: January 2020

Cellulolytic bacteria were enumerated and cellulase activity was determined over a 98-day period from fecal samples of gestating swine fed various levels and sources of fiber. The diets, each fed to five pigs, were a corn-soybean control, 20% corn cobs, and 40 and 96% alfalfa meal. Fecal samples were collected from all pigs on days 0, 5, 14, 21, 35, 49, 70, and 98. Overall, the most probable number of cellulolytic bacteria from pigs fed the control, 20% corn cobs, and 40 and 96% alfalfa meal was 23.3 X 10(8), 15.2 X 10(8), 45.1 X 10(8), and 52.5 X 10(8) per g (dry weight) of fecal sample, respectively. Enumeration of cellulolytic bacteria by counting zones of clearing in roll tubes, as compared with the most probable number procedure, accounted for only 1.1 and 17.0% of the cellulolytic bacteria, respectively, from pigs fed the control or 96% alfalfa meal diet. Cellulolytic bacteria (most probable number) on days 70 and 98 accounted for 4.1 and 10.0% of the viable count for the pigs fed the control and 96% alfalfa meal diets, respectively. The viable count was not different between pigs fed the control and 96% alfalfa meal diets. The overall mean cellulolytic activity (milligrams of glucose released from carboxymethyl cellulose per gram [dry weight] fecal sample per 30 min was 17.0, 19.9, 23.8, and 20.6, respectively, for the control, 20% corn cobs, and 40 and 96% alfalfa meal diets. The results indicate that the cellulolytic flora can be increased by prolonged feeding of high-fiber diets and may represent 10% of the culturable flora.
A device for the nondestructive decontamination of large volumes of infected egg waste
Authors: Ackland N R , Tannock G A , Young I F
Published: January 2020

A device for the decontamination of large numbers of infected eggs which remain as by-products of vaccine production is described. Homogenates of infected eggs were heated to 60 degrees C and maintained at that temperature for 3 h in a specially constructed recirculation tank. The infectivity of all detectable influenza viruses and more than 99% of the bacteria associated with the homogenates was destroyed by this procedure. Eggshell material was separated from the proteins present in the homogenate at the end of the heating cycle by means of a cyclone separator. The proportions of all the amino acids, except cystine, in the proteins remaining in the suspension after the heating cycle were similar to that normally present in whole embryos.
Monensin-based medium for determination of total gram-negative bacteria and Escherichia coli
Authors: Petzel J P , Hartman P A
Published: January 2020

Plate count-monensin-KCl (PMK) agar, for enumeration of both gram-negative bacteria and Escherichia coli, is composed of (per liter) 23.5 g of plate count agar, 35 mg of monensin, 7.5 g of KCl, and 75 mg of 4-methylumbelliferyl-beta-D-glucuronide (MUG). Monensin was added after the medium was sterilized. The diluent of choice for use with PMK agar was 0.1% peptone (pH 6.8); other diluents were unsatisfactory. Gram-negative bacteria (selected for by the ionophore monensin) can be used to judge the general quality or sanitary history of a commodity. E. coli (differentiated by its ability to hydrolyze the fluorogenic compound MUG) can be used to assess the safety of a commodity in regard to the possible presence of enteric pathogens. Pure-culture studies demonstrated that monensin completely inhibited gram-positive bacteria and had little or no effect on gram-negative bacteria. When gram-negative bacteria were injured by one of several methods, a few species (including E. coli) became sensitive to monensin; this sensitivity was completely reversed in most instances by the inclusion of KCl in the medium. When PMK agar was tested with food and environmental samples, 96% of 535 isolates were gram negative; approximately 68% of colonies from nonselective medium were gram negative. PMK agar was more selective than two other media against gram-positive bacteria and was less inhibitory for gram-negative bacteria. However, with water samples, KCl had an inhibitory effect on gram-negative bacteria, and it should therefore be deleted from monensin-containing medium for water analysis.(ABSTRACT TRUNCATED AT 250 WORDS)
Nitrogen Fixation Associated with the New Zealand Mangrove (
Avicennia marina
(Forsk.) Vierh. var.
resinifera
(Forst. f.) Bakh.)
Authors: Hicks Brendan J. , Silvester Warwick B.
Published: January 2020

Nitrogenase activity in mangrove forests at two locations in the North Island, New Zealand, was measured by acetylene reduction and
15
N
2
uptake. Nitrogenase activity (C
2
H
2
reduction) in surface sediments 0 to 10 mm deep was highly correlated (
r
= 0.91,
n
= 17) with the dry weight of decomposing particulate organic matter in the sediment and was independent of light. The activity was not correlated with the dry weight of roots in the top 10 mm of sediment (
r
= −0.01,
n
= 13). Seasonal and sample variation in acetylene reduction rates ranged from 0.4 to 50.0 μmol of C
2
H
4
m
−2
h
−1
under air, and acetylene reduction was depressed in anaerobic atmospheres. Nitrogen fixation rates of decomposing leaves from the surface measured by
15
N
2
uptake ranged from 5.1 to 7.8 nmol of N
2
g (dry weight)
−1
h
−1
, and the mean molar ratio of acetylene reduced to nitrogen fixed was 4.5:1. Anaerobic conditions depressed the nitrogenase activity in decomposing leaves, which was independent of light. Nitrogenase activity was also found to be associated with pneumatophores. This activity was light dependent and was probably attributable to one or more species of
Calothrix
present as an epiphyte. Rates of activity were generally between 100 and 500 nmol of C
2
H
4
pneumatophore
−1
h
−1
in summer, but values up to 1,500 nmol of C
2
H
4
pneumatophore
−1
h
−1
were obtained.
Oxidation of acyclic terpenoids by Corynebacterium sp
Authors: Yamada Y , Seo C W , Okada H
Published: January 2020

Squalene analogs such as lycopersene, geranylfarnesyl, digeranyl, and 2-hydroxy-2,3-dihydrosqualene and terpene alcohol derivatives such as farnesyl benzyl ether, farnesyl pivalate, geranylgeranyl pivalate, geranyl pivalate, and geranyl benzyl ether were oxidized by Corynebacterium sp. strain SY-79, which was isolated from soil by using squalene as a carbon source. Lycopersene and geranylfarnesyl gave no major product. Digeranyl, geranyl benzyl ether, and geranyl pivalate gave terminal oxidation products, and 2-hydroxy-2,3-dihydrosqualene, farnesyl benzyl ether, farnesyl pivalate, and geranylgeranyl pivalate were degraded to give lower molecular carboxylic acids. Strain SY-79 showed promising oxidative activities toward acyclic terpenes, although the metabolites obtained were variable, depending upon the structure of the substrate.
Influence of
Azospirillum
Strains on the Nodulation of Clovers by
Rhizobium
Strains
Authors: Plazinski Jacek , Rolfe Barry G.
Published: January 2020

Mixed cultures of several
Azospirillum
and
Rhizobium trifolii
strains caused either an inhibition or stimulation of nodule formation on plant hosts as compared with nodulation of plants inoculated with
R. trifolii
alone.
Azospirillum
strains affected the nodulation process at a precise cell ratio (
R. trifolii/Azospirillum
cells) and time of inoculation. All
Azospirillum
strains used showed a variation in their ability to inhibit or enhance nodulation by
R. trifolii
strains. When nonviable cell preparations of
Azospirillum
strains were used for mixing experiments, no effect on nodulation was observed. A decrease in the effectiveness of normally Nod
+
Fix
+
R. trifolii
strains was observed when an
Azospirillum
strain caused an increase in nodule number.
Partial Purification and Characterization of a Polysaccharide Depolymerase Associated with Phage-Infected
Erwinia amylovora
Authors: Vandenbergh Peter A. , Wright Ann M. , Vidaver Anne K.
Published: January 2020

Erwinia amylovora
infected with bacteriophage ERA103 produced an enzyme which degraded the extracellular polysaccharide of noninfected cells. The depolymerase enzyme was purified 15-fold by a procedure which included ammonium sulfate precipitation, ultracentrifugation, CM-Sephadex batchwise separation, Sephadex G-50 column chromatography, and Sephacryl S-200 column chromatography. The enzyme had a molecular weight of approximately 21,000 and a pH optimum of 6.0. Activity was enhanced by supplements of 2-mercaptoethanol or dithiothreitol.