bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of a Yellowstone hot spring microbial community by 5S rRNA sequences
Authors: Stahl D A , Lane D J , Olsen G J , Pace N R
Published: January 2020

The microorganisms inhabiting a 91 degrees C hot spring in Yellowstone National Park were characterized by sequencing 5S rRNAs isolated from the mixed, natural microflora without cultivation. By comparisons of these sequences with reference sequences, the phylogenetic relationships of the hot spring organisms to better characterized ones were established. Quantitation of the total 5S-sized rRNAs revealed a complex microbial community of three dominant members, a predominant archaebacterium affiliated with the sulfur-metabolizing (dependent) branch of the archaebacteria, and two eubacteria distantly related to Thermus spp. The archaebacterial and the eubacterial 5S rRNAs each constituted about half the examined population.
Inhibition by antimicrobial food additives of ochratoxin A production by Aspergillus sulphureus and Penicillium viridicatum
Authors: Tong C H , Draughon F A
Published: January 2020

The effects of antimicrobial food additives on growth and ochratoxin A production by Aspergillus sulphureus NRRL 4077 and Penicillium viridicatum NRRL 3711 were investigated. At pH 4.5, growth and toxin production by both A. sulphureus and P. viridicatum were completely inhibited by 0.02% potassium sorbate, 0.067% methyl paraben, 0.0667% methyl paraben, and 0.2% sodium propionate. At pH 5.5, 0.134% potassium sorbate and 0.067% methyl paraben completely inhibited growth and ochratoxin A production by both fungi. Sodium bisulfite at 0.1%, the maximum level tested, was found to inhibit growth of A. sulphureus and P. viridicatum by 45 and 89%, respectively. Toxin production was inhibited by 97 and 99%, respectively. Sodium propionate (0.64%) at pH 5.5 inhibited growth of A. sulphureus and P. viridicatum by 76 and 90%, respectively. Toxin production was inhibited by greater than 99% for each fungus. Antimicrobial agents were ranked as to effectiveness by comparing the level required for complete inhibition of ochratoxin A production to the highest antimicrobial agent level normally used in food. At pH 4.5, the most effective inhibitor of growth and toxin production was potassium sorbate, followed by sodium propionate, methyl paraben, and sodium bisulfite, respectively, for both fungi. However, at pH 5.5, the most effective antimicrobial agents for inhibiting ochratoxin production were methyl paraben and potassium sorbate, followed by sodium propionate. Sodium bisulfite was not highly inhibitory to these toxigenic fungi at the higher pH value tested.
Elimination of viruses and indicator bacteria at each step of treatment during preparation of drinking water at seven water treatment plants
Authors: Payment P , Trudel M , Plante R
Published: January 2020

Seven drinking water treatment plants were sampled twice a month for 12 months to evaluate the removal of indicator bacteria and cytopathogenic enteric viruses. Samples were obtained at each level of treatment: raw water, postchlorination, postsedimentation, postfiltration, postozonation, and finished (tap) water. Raw water quality was usually poor, with total coliform counts exceeding 105 to 106 CFU/liter and the average virus count in raw water of 3.3 most probable number of cytopathogenic units (MPNCU)/liter; several samples contained more than 100 MPNCU/liter. All plants distributed finished water that was essentially free of indicator bacteria as judged by analysis of 1 liter for total coliforms, fecal coliforms, fecal streptococci, coagulase-positive staphylococci, and Pseudomonas aeruginosa. The total plate counts at 20 and 35 degrees C were also evaluated as a measure of the total microbial population and were usually very low. Viruses were detected in 7% (11 of 155) of the finished water samples (1,000 liters) at an average density of 0.0006 MPNCU/liter the highest virus density measured being 0.2 MPNCU/liter. The average cumulative virus reduction was 95.15% after sedimentation and 99.97% after filtration and did not significantly decrease after ozonation or final chlorination. The viruses isolated from treated waters were all enteroviruses: poliovirus types 1, 2, and 3, coxsackievirus types B3, B4, and B5, echovirus type 7, and untyped picornaviruses.
Selective Isolation of
Bacillus sphaericus
from Soil by Use of Acetate as the Only Major Source of Carbon
Authors: Massie Julie , Roberts Graham , White Peter J.
Published: January 2020

A simple chemically defined medium containing sodium acetate (37 or 74 mM) as the only major source of carbon was inoculated with soil from various locations. The bacteria which grew most rapidly at 30°C were almost entirely strains of
Bacillus sphaericus
and
Arthrobacter
species. Pasteurization of the soils made the medium selective for
B. sphaericus.
Several new strains were isolated, and the peptidoglycans of their cell walls were examined.
Serotyping of Campylobacter jejuni, Campylobacter coli, and Campylobacter laridis from domestic and wild animals
Authors: Rosef O , Kapperud G , Lauwers S , Gondrosen B
Published: January 2020

By using 50 unabsorbed antisera, we were able to serotype 272 (65.7%) of 414 thermotolerant campylobacters from wild and domestic animals, on the basis of heat-stable antigens identified by means of passive hemagglutination. Forty-two serotypes were recognized. The pattern of serotypes detected in the various animal species was compared to human clinical isolates by using the Czekanowski index (proportional similarity index). The highest degree of similarity to the clinical isolates was observed for the poultry isolates, followed by strains from wild birds, flies, and pigs (in order of decreasing similarity). The serotypes recovered most frequently from poultry (LAU 1 and LAU 2) were also most prevalent in Norwegian patients. In contrast, serotype LAU 35/44, the predominant porcine serotype, was never recovered from human clinical specimens. Flies captured in chicken farms and in piggeries harbored serotypes which were also commonly seen in chickens and pigs, respectively. Nine of the strains included in this study could not be ascribed to any defined species. All of these were resistant to nalidixic acid and did not produce H2S.
Tatlockia micdadei (Pittsburgh pneumonia agent) growth kinetics may explain its infrequent isolation from water and the low prevalence of Pittsburgh pneumonia
Authors: Best M G , Stout J E , Yu V L , Muder R R
Published: January 2020

Sediment and indigenous microflora taken from water distribution systems has been shown to promote the survival of Legionella pneumophila. The effect of sediment and indigenous microflora on Tatlockia micdadei (Pittsburgh pneumonia agent, PPA) was evaluated by growth curve experiments. Symbiosis between PPA and environmental bacteria was demonstrated by satellitism experiments. Unlike L. pneumophila, the concentration of PPA remained stationary in test tube suspensions containing both microflora and sediment. The difference in the ecology between the two organisms may explain the infrequent environmental recovery of PPA and, ultimately, the epidemiologic differences between Legionnaires disease and Pittsburgh pneumonia.
Minimum Threshold for Hydrogen Metabolism in Methanogenic Bacteria
Authors: Lovley Derek R.
Published: January 2020

Methanogenic isolates did not consume hydrogen below partial pressures of 6.5 Pa. Thus, in contrast to a previous report, results from pure-culture studies do not invalidate the threshold model for methane production from hydrogen in sediments.
Selective Medium for Mosquito-Pathogenic Strains of
Bacillus sphaericus
Authors: Yousten Allan A. , Fretz Susan B. , Jelley Scott A.
Published: January 2020

A selective medium (BATS), which contains arginine as the sole carbon and nitrogen source and which also contains streptomycin, allowed growth of 18 mosquito-pathogenic strains of
Bacillus sphaericus
. It inhibited the growth of 68% of the nonpathogenic
B. sphaericus
strains tested as well as other
Bacillus
spp. and aquatic bacteria.
Effect of Photon Fluence Rate and Specific Growth Rate on Geosmin Production of the Cyanobacterium
Oscillatoria brevis
(Kütz.) Gom
Authors: Naes H. , Aarnes H. , Utkilen H. C. , Nilsen S. , Skulberg O. M.
Published: January 2020

The production of geosmin from the cyanobacterium
Oscillatoria brevis
was studied as a function of the photon fluence rate and appears to be related to the chlorophyll content.
Modified Medium for the Oxidation-Fermentation Test in the Identification of Marine Bacteria
Authors: Lemos Manuel L. , Toranzo Alicia E. , Barja Juan L.
Published: January 2020

Using the medium of ZoBell as a basal formulation, we developed a medium to determine the oxidative-fermentative metabolism in marine bacteria. Different oxidative and fermentative collection strains, as well as a group of unidentified marine bacteria, were tested on modified ZoBell medium and other conventional media. In general, superior results were obtained with the modified ZoBell medium since it supported good bacterial growth and gave more clear-cut oxidative reactions.
Genetic Rearrangement of Plasmids: In Vivo Recombination between a Dehalogenation Plasmid and Multiple-Resistance Plasmid RP4 in
Pseudomonas
sp
Authors: Kawasaki Haruhiko , Takao Makoto , Koiso Akiko , Tonomura Kenzo
Published: January 2020

When
Moraxella
plasmid pUO1 encoding haloacetate dehalogenase and mercury resistance coexisted with IncP-1 plasmid RP4 in
Pseudomonas
sp., genetic exchange between the plasmids often occurred, probably by site-specific recombination. The recombinant plasmids obtained were classified into four groups on the basis of phenotype. Representative plasmids for each group were analyzed for DNA composition and function, and the mechanism for the formation of these plasmids was sought. They were inherited stably in
Escherichia coli
and a
Pseudomonas
sp.
Effect of Reactor Turbulence on the Binding-Protein-Mediated Aspartate Transport System in Thin Wastewater Biofilms
Authors: Eighmy T. Taylor , Bishop P. L.
Published: January 2020

This research documents an effect of reactor turbulence on the ability of gram-negative wastewater biofilm bacteria to actively transport
l
-aspartate via a binding-protein-mediated transport system. Biofilms which were not preadapted to turbulence and which possessed two separate and distinct aspartate transport systems (systems 1 and 2) were subjected to a turbulent flow condition in a hydrodynamically defined closed-loop reactor system. A shear stress treatment of 3.1 N · m
−2
for 10 min at a turbulent Reynolds number (Re = 11,297) inactivated the low-affinity, high-capacity binding-protein-mediated transport system (system 2) and resolved the high-affinity, low-capacity membrane-bound proton symport system (system 1). The

K
t

and
V
max
values for the resolved system were statistically similar to
K
t
and
V
max
values for system 1 when system 2 was inactivated either by osmotic shock or arsenate, two treatments which are known to inactivate binding-protein-mediated transport systems. We hypothesize that shear stress disrupts system 2 by deforming the outer membranes of the firmly adhered gram-negative bacteria.
Seasonal changes in the ruminal microflora of the high-arctic Svalbard reindeer (Rangifer tarandus platyrhynchus)
Authors: Orpin C G , Mathiesen S D , Greenwood Y , Blix A S
Published: January 2020

The dominant rumen bacteria in high-arctic Svalbard reindeer were characterized, their population densities were estimated, and ruminal pH was determined in summer, when food quality and availability are good, and in winter, when they are poor. In summer the total cultured viable population density was (2.09 +/- 1.26) X 10(10) cells ml-1, whereas in winter it was (0.36 +/- 0.29) X 10(10) cells ml-1, representing a decrease to 17% of the summer population density. On culture, Butyrivibrio fibrisolvens represented 22% of the bacterial population in summer and 30% in winter. Streptococcus bovis represented 17% of the bacterial population in summer but only 4% in winter. Methanogenic bacteria were present at 10(4) cells ml-1 in summer and 10(7) cells ml-1 in winter. In summer and winter, respectively, the proportions of the viable population showing the following activities were as follows: starch utilization, 68 and 63%; fiber digestion, 31 and 74%; cellulolysis, 15 and 35%; xylanolysis, 30 and 58%; proteolysis, 51 and 28%; ureolysis, 40 and 54%; and lactate utilization, 13 and 4%. The principal cellulolytic bacterium was B. fibrisolvens, which represented 66 and 52% of the cellulolytic population in summer and winter, respectively. The results indicate that the microflora of the rumen of Svalbard reindeer is highly effective in fiber digestion and nitrogen metabolism, allowing the animals to survive under the austere nutritional conditions typical of their high-arctic habitat.
Construction of a cosmid clone library of Pseudomonas syringae pv. phaseolicola and isolation of genes by functional complementation
Authors: Ehrenshaft M , Mills D
Published: January 2020

A genomic library constructed from a wild-type strain of Pseudomonas syringae pv. phaseolicola in the broad-host-range cosmid vector pVK102 was used to isolate wild-type genes by complementation of Tn5-induced auxotrophic mutants. Selection pressure was required for maintenance of the vector and members of the library in strains of P. syringae.
Occurrence of Campylobacter jejuni and Giardia species in muskrat (Ondatra zibethica)
Authors: Pacha R E , Clark G W , Williams E A
Published: January 2020

A total of 189 muskrat fecal samples were surveyed for Campylobacter and Giardia species. Campylobacter jejuni was recovered from 47.5% of these samples, and Giardia species were detected in 82.5%. These findings indicate that muskrat may be of importance to the health both of humans and of domestic animals.
Carbohydrate Catabolism in
Azospirillum amazonense
Authors: Martínez-Drets G. , Fabiano E. , Cardona A.
Published: January 2020

The nitrogen fixer
Azospirillum amazonense
grew on the various disaccharides, hexoses, and pentoses tested in this study but not on polyols and on some tricarboxylic acid cycle intermediates. An active transport system was detected for sucrose and glucose but not for mannitol and 2-ketoglutarate. Six
A. amazonense
strains were examined for 16 carbon-metabolizing enzymes, and the results indicate that these strains employ the Entner-Doudoroff pathway to catabolize sucrose, fructose, and glucose. The hexose monophosphate and Embden-Meyerhof-Parnas pathways were not detectable.
Enhanced chlorine resistance of tap water-adapted Legionella pneumophila as compared with agar medium-passaged strains
Authors: Kuchta J M , States S J , McGlaughlin J E , Overmeyer J H , Wadowsky R M , McNamara A M , Wolford R S , Yee R B
Published: January 2020

Previous studies have shown that bacteria maintained in a low-nutrient "natural" environment such as swimming pool water are much more resistant to disinfection by various chemical agents than strains maintained on rich media. In the present study a comparison was made of the chlorine (Cl2) susceptibility of hot-water tank isolates of Legionella pneumophila maintained in tap water and strains passaged on either nonselective buffered charcoal-yeast extract or selective differential glycine-vancomycin-polymyxin agar medium. Our earlier work has shown that environmental and clinical isolates of L. pneumophila maintained on agar medium are much more resistant to Cl2 than coliforms are. Under the present experimental conditions (21 degrees C, pH 7.6 to 8.0, and 0.25 mg of free residual Cl2 per liter, we found the tap water-maintained L. pneumophila strains to be even more resistant than the agar-passaged isolates. Under these conditions, 99% kill of tap water-maintained strains of L. pneumophila was usually achieved within 60 to 90 min compared with 10 min for agar-passaged strains. Samples from plumbing fixtures in a hospital yielded legionellae which were "super"-chlorine resistant when assayed under natural conditions. After one agar passage their resistance dropped to levels of comparable strains which had not been previously exposed to additional chlorination. These studies more closely approximate natural conditions than our previous work and show that tap water-maintained L. pneumophila is even more resistant to Cl2 than its already resistant agar medium-passaged counterpart.
Influence of salts and temperature on the transfer of mercury resistance from a marine pseudomonad to Escherichia coli
Authors: Gauthier M J , Cauvin F , Breittmayer J P
Published: January 2020

Thirty-one strains of marine bacteria were examined for their ability to transfer mercury resistance to Escherichia coli in complex media; eight strains were able to transfer their resistance marker, with frequencies ranging from 10(-3) to 10(-8). Frequencies generally increased with the increase of the mating period. Additional mating experiments were carried out with one strain, belonging to the pseudomonads, to estimate the influence of temperature, salinity, and time on the conjugal transfer frequency of mercury resistance markers. The higher frequencies occurred at 30 degrees C, in a salt medium (37%), after 24 h of mating.
Evidence for plasmid- and chromosome-borne multiple nif genes in Rhizobium fredii
Authors: Barbour W M , Mathis J N , Elkan G H
Published: January 2020

Rhizobium fredii is a fast-growing rhizobium isolated from the primitive Chinese soybean cultivar Peking and from the wild soybean Glycine soja. This rhizobium harbors nif genes on 150- to 200-megadalton plasmids. By passage on acridine orange plates, we obtained a mutant of R. fredii USDA 206 cured of the 197-megadalton plasmid (USDA 206C) which carries both nif and nod genes. This strain, however, has retained its symbiotic effectiveness. Probing EcoRI digests of wild-type and cured plasmid DNA with a 2.2-kilobase nif DH fragment from Rhizobium meliloti has shown four homologous fragments in the wild-type strain (4.2, 4.9, 10, and 11 kilobases) and two fragments in the cured strain (4.2 and 10 kilobases). EcoRI digests of total DNA show four major bands of homology (4.2, 4.9, 5.8, and 13 kilobases) in both the wild-type and cured strains. The presence of major bands of homology in the total DNA not present in the plasmid DNA indicated chromosomal nif genes. Probing of HindIII digests of total and plasmid DNA led to the same conclusion. Hybridization to the smaller plasmids of USDA 206 and USDA 206C showed the presence of nif genes on at least one of these plasmids, explaining the nif homology in the USDA 206C plasmid digests.
Comparison of several control standard endotoxins to the National Reference Standard Endotoxin--an HIMA collaborative study
Authors: Pearson F C , Weary M E , Sargent H E , Novitsky T J , Lin H , Lindsay G , Berzofsky R N , Lane A L , Wilson J D , Cooper J F
Published: January 2020

A collaborative study, initiated under the auspices of the Health Industry Manufacturers Association (HIMA), was designed to establish the relationship of Escherichia coli O55:B5 endotoxin (the control standard endotoxin of HIMA and the Food and Drug Administration's Office of Medical Devices) to the U.S. National Reference Standard Endotoxin and to two internationally used control standard endotoxins. By using two Limulus amoebocyte lysate test systems, it was established that the E. coli O55:B5 endotoxin lot originally used by HIMA and the Office of Medical Devices to establish Limulus amoebocyte lysate release test criteria for pyrogen testing of medical devices contains approximately 4.5 endotoxin units (EU) per ng. Thus, the 1.0-ng/kg endotoxin dose limit currently established for medical devices is approximately the same as the 5.0-EU/kg endotoxin limit (on an activity basis) established by several other Food and Drug Administration agencies for human and animal parenteral drugs and biological products.
Marine Ammonia- and Nitrite-Oxidizing Bacteria: Serological Diversity Determined by Immunofluorescence in Culture and in the Environment
Authors: Ward B. B. , Carlucci A. F.
Published: January 2020

Immunofluorescence assays for marine ammonium- and nitrite-oxidizing bacteria were used to assess the diversity of nitrifying bacteria isolated from marine environments. The antisera show relatively broad specificity, in that each reacts with several strains of the same physiological type as the strain to which the antiserum was prepared. The antisera do not, however, react with any strains of differing physiological type. Seventy percent of the 30 unidentified ammonium-oxidizing isolates tested reacted with one or both of the antisera produced to marine ammonium-oxidizing strains, and 8 of the 9 unidentified nitrite-oxidizing strains tested reacted with 1 or more of the 3 nitrite oxidizer antisera used. Ammonium- and nitrite-oxidizing bacteria were enumerated in samples taken in a depth profile (to 750 m) in the Southern California Bight by immunofluorescence assays for two ammonium oxidizers and two nitrite oxidizers. Average abundances of the two types of nitrifiers were 3.5 � 10
5
and 2.8 � 10
5
cells liter
−1
, respectively. Nitrifiers constitute 0.1 to 0.8% of the total bacterial population in these samples.
Treponema saccharophilum sp. nov., a large pectinolytic spirochete from the bovine rumen
Authors: Paster B J , Canale-Parola E
Published: January 2020

A large, obligately anaerobic spirochete (strain PB) was isolated from bovine rumen fluid by a procedure involving rifampin as a selective agent. The helical cells measured 0.6 to 0.7 micron by 12 to 20 micron and possessed approximately 16 periplasmic flagella inserted near each end of the protoplasmic cylinder. The periplasmic flagella were arranged in a bundle wound around the cell body. Strain PB utilized as fermentable substrates various plant polysaccharides (e.g., pectin, arabinogalactan, starch, and inulin) as well as pentoses, hexoses, disaccharides, and uronic acids. Glucose was fermented to acetate, formate, and ethanol, whereas the fermentation of pectin or glucuronic acid yielded only acetate and formate as major end products. Determinations of radioactivity in end products and assays of enzymatic activities indicated that strain PB catabolized glucose via the Embden-Meyerhof pathway. Extracts of cells grown in pectin-containing media possessed relatively high levels of phospho-2-keto-3-deoxygluconate aldolase activity, an enzymatic activity typical of the Entner-Doudoroff pathway. The guanine-plus-cytosine content of the DNA of strain PB (54 mol%) was considerably higher than that of known host-associated anaerobic spirochetes. This study indicates that strain PB represents a new species of Treponema, for which we propose the name Treponema saccharophilum.
Phenotypic expression of Kluyveromyces lactis killer toxin against Saccharomyces spp
Authors: Panchal C J , Meacher C , Van Oostrom J , Stewart G G
Published: January 2020

The secretion of killer toxins by some strains of yeasts is a phenomenon of significant industrial importance. The activity of a recently discovered Kluyveromyces lactis killer strain against a sensitive Saccharomyces cerevisiae strain was determined on peptone-yeast extract-nutrient agar plates containing as the carbon source glucose, fructose, galactose, maltose, or glycerol at pH 4.5 or 6.5. Enhanced activity (50 to 90% increase) was found at pH 6.5, particularly on the plates containing galactose, maltose, or glycerol, although production of the toxin in liquid medium was not significantly different with either glucose or galactose as the carbon source. Results indicated that the action of the K. lactis toxin was not mediated by catabolite repression in the sensitive strain. Sensitivities of different haploid and polyploid Saccharomyces yeasts to the two different killer yeasts S. cerevisiae (RNA-plasmid-coded toxin) and K. lactis (DNA-plasmid-coded toxin) were tested. Three industrial polyploid yeasts sensitive to the S. cerevisiae killer yeast were resistant to the K. lactis killer yeast. The S. cerevisiae killer strain itself, however, was sensitive to the K. lactis killer yeast.
Inactivation of Norwalk virus in drinking water by chlorine
Authors: Keswick B H , Satterwhite T K , Johnson P C , DuPont H L , Secor S L , Bitsura J A , Gary G W , Hoff J C
Published: January 2020

Norwalk virus in water was found to be more resistant to chlorine inactivation than poliovirus type 1 (LSc2Ab), human rotavirus (Wa), simian rotavirus (SA11), or f2 bacteriophage. A 3.75 mg/liter dose of chlorine was found to be effective against other viruses but failed to inactivate Norwalk virus. The Norwalk virus inoculum remained infectious for five of eight volunteers, despite the initial presence of free residual chlorine. Infectivity in volunteers was demonstrated by seroconversion to Norwalk virus. Fourteen of 16 subjects receiving untreated inoculum seroconverted to Norwalk virus. Illness was produced in four of the eight volunteers and in 11 of 16 control subjects. A similar Norwalk virus inoculum treated with a 10 mg/liter dose of chlorine produced illness in only one and failed to induce seroconversion in any of eight volunteers. Free chlorine (5 to 6 mg/liter) was measured in the reaction vessel after a 30-minute contact period. Norwalk virus appears to be very resistant to chlorine which may explain its importance in outbreaks of waterborne disease.
Fungal metabolism of tert-butylphenyl diphenyl phosphate
Authors: Heitkamp M A , Freeman J P , McMillan D C , Cerniglia C E
Published: January 2020

The fungal metabolism of tert-butylphenyl diphenyl phosphate (BPDP) was studied. Cunninghamella elegans was incubated with BPDP for 7 days, and the metabolites formed were separated by thin-layer, gas-liquid, or high-pressure liquid chromatography and identified by 1H nuclear magnetic resonance and mass spectral techniques. C. elegans metabolized BPDP predominantly at the tert-butyl moiety to form the carboxylic acid 4-(2-carboxy-2-propyl)triphenyl phosphate. In addition, 4-hydroxy-4'-(2-carboxy-2-propyl)triphenyl phosphate, triphenyl phosphate, diphenyl phosphate, 4-(2-carboxy-2-propyl)diphenyl phosphate, 2-(4-hydroxyphenyl)-2-methyl propionic acid, and phenol were detected. Similar metabolites were found in the 28 fungal cultures which were examined for their ability to metabolize BPDP. Experiments with [14C]BPDP indicated that C. elegans metabolized 70% of the BPDP after 7 days and that the ratio of organic-soluble metabolites to water-soluble metabolites was 8:2. The results indicate that fungi preferentially oxidize BPDP at the alkyl side chain and at the aromatic rings to form hydroxylated derivatives. The trace levels of mono- and diaryl metabolites and the low level of phosphotriesterase activity measured in C. elegans indicate that phosphatase cleavage is a minor pathway for fungal metabolism of BPDP.
Inhibition of germinant binding by bacterial spores in acidic environments
Authors: Blocher J C , Busta F F
Published: January 2020

Commitment to germinate occurred in both Clostridium botulinum and Bacillus cereus spores during 0.5 min of exposure to 100 mM L-alanine or L-cysteine, measured by the inability of germination inhibitors (D form of amino acid) to inhibit germination. Spore germination at pH 4.5 was inhibited because the germinant did not bind to the trigger sites. C. botulinum spores exposed to 100 mM L-alanine or L-cysteine at pH 4.5 remained sensitive to D-amino acid inhibition at pH 7, indicating that no germinants had bound to the trigger site at pH 4.5. Inhibition of germinant binding at pH 4.5 was reversible but lagged in commitment to germinate upon transfer to pH 7. Spores sequentially exposed to pH 4.5 buffer and pH 7 buffer with the germinant also demonstrated a lag in commitment to germinate. The pH at which binding was inhibited was not significantly affected by composition of the buffer or by reduced germinant concentrations (10 mM). Nonspecific uptake of L-[3H]alanine by C. botulinum spores was not inhibited at pH 4.5. Inhibition of germinant binding in acidic environments appeared to be due to protonation of a functional group in or near the trigger site. This may represent a general mechanism for inhibition of spore germination in acidic environments.
Enteroviruses in sludge: multiyear experience with four wastewater treatment plants
Authors: Hamparian V V , Ottolenghi A C , Hughes J H
Published: January 2020

We describe our experience with the isolation of viruses from four treatment plants located in different geographic areas. Over a period of 3 years, 297 enteroviruses were isolated from 307 sludge samples. The highest frequency of viral isolation (92%), including multiple isolates from single samples, was obtained from a treatment plant serving the smallest population. Excluding the polioviruses, 22 different enterovirus serotypes were isolated. The methods used to isolate the viruses were relatively simple and included an elution procedure in which beef extract was used and a disinfection step. No concentration procedure was used. Of three cell culture systems used, the RD line of human rhabdomyosarcoma cells was by far the most useful for the isolation of echoviruses; BGM and HeLa cells were particularly useful for the isolation of group B coxsackieviruses. A seasonal effect on viral isolation rates from sludge was observed.
Possible role of streptomycin released from spore cell wall of Streptomyces griseus
Authors: Szab� I , Benedek A , Barab�s G
Published: January 2020

Vegetative mycelia and spores of the investigated high- and low-producer strains of Streptomyces griseus bound significant amounts (4%) of streptomycin, which could be removed by increasing ionic strength. The release of antibiotic from the spores was easier when the spores were germinating. This phenomenon is considered to play an ecological role. We suppose that the streptomycin released during the germination process may protect the young hyphae from the different bacteria growing in the microenvironment of the Streptomyces spores.
Microbial Manganese Reduction by Enrichment Cultures from Coastal Marine Sediments
Authors: Burdige David J. , Nealson Kenneth H.
Published: January 2020

Manganese reduction was catalyzed by enrichment cultures of anaerobic bacteria obtained from coastal marine sediments. In the absence of oxygen, these enrichment cultures reduced manganates when grown on either lactate, succinate, or acetate in both sulfate-free and sulfate-containing artificial seawaters. Sodium azide as well as oxygen completely inhibited microbial manganese reduction by these enrichment cultures, whereas molybdate had no effect on them. The addition of nitrate to the medium slightly decreased the rate of Mn
2+
production by these enrichment cultures. These findings are consistent with the hypothesis that the manganese-reducing organisms in these enrichment cultures use manganates as terminal electron acceptors and couple manganese reduction in some way to the oxidation of organic matter.
Membrane-associated viral complexes observed in stools and cell culture
Authors: Williams F P
Published: January 2020

Viral complexes observed to be membrane associated rather than clumped by antibody were detected in a rotavirus-containing stool specimen by negative-stain electron microscopy. These "viral packets" were also observed in cell culture fluids after repeated passaging and contained up to 100 virions. Other stool specimens have been observed to contain similar packets of parvovirus-like particles. Such complexes must be expected in fecally contaminated water.
Ethylene dibromide transformation under methanogenic conditions
Authors: Bouwer E J , McCarty P L
Published: January 2020

Ethylene dibromide present at a low concentration (less than 100 micrograms/liter) was transformed by reductive dehalogenation under methanogenic conditions in batch bacterial cultures and in a continuous-flow, methanogenic, fixed-film, laboratory-scale column.
Comparison of methods for isolating Campylobacter jejuni from raw milk
Authors: Hunt J M , Francis D W , Peeler J T , Lovett J
Published: January 2020

The method of Doyle and Roman (Appl. Environ. Microbiol. 43:1343-1353, 1982) was compared with that of Lovett et al. (Appl. Environ. Microbiol. 46:459-462, 1983) for the ability to recover Campylobacter jejuni strains inoculated into raw milk at a concentration of less than 1 cell per g. The method of Lovett et al. gave significantly greater recovery proportions.
Construction of cloning, promoter-screening, and terminator-screening shuttle vectors for Bacillus subtilis and Streptococcus lactis
Authors: van der Vossen J M , Kok J , Venema G
Published: January 2020

Shuttle vectors have been constructed which are suitable both for the selection of regulatory sequences and for gene cloning in Bacillus subtilis and Streptococcus lactis. The promoter screening vectors contain a promoterless chloramphenicol acetyltransferase gene; the insertion of suitable DNA fragments upstream of the gene restored the enzyme activity. With a related set of vectors, transcription termination signals can be selected.
Occurrence of β-Aminoglutaric Acid in Marine Bacteria
Authors: Henrichs Susan M. , Cuhel Russell
Published: January 2020

β-Aminoglutaric acid, a nonprotein amino acid isomer of glutamic acid, was found in the free amino acid pool of a marine bacterium,
Alteromonas luteoviolacea.
It was also found in a mixed culture of fermenting bacteria enriched from an anoxic marine sediment.
Comparison of Media for the Isolation of
Cryptococcus neoformans
Authors: Racicot Terry A. , Bulmer Glenn S.
Published: January 2020

Four media, Staib's
Guizotia abyssinica
, trypan blue, and Staib's with 2 and 10 mg of methyl violet per liter, were compared for the selective and differential isolation of
Cryptococcus neoformans
from environmental samples. Trypan blue medium allowed for the differentiation of
C. neoformans
colonies from
Candida albicans
colonies several days earlier than did Staib's medium. The addition of methyl violet to Staib's medium was found to be inhibitory to some strains of all species tested. Diphenyl in Staib's medium inhibited the growth of 30 strains of
C. neoformans
and
C. albicans.
Selective Delignification of Aspen Wood Blocks In Vitro by Three White Rot Basidiomycetes
Authors: Otjen Lewis , Blanchette Robert A.
Published: January 2020

Aspen wood blocks were selectively delignified in the laboratory by
Ischnoderma resinosum, Poria medulla-panis
, and
Xylobolus frustulatus.
After 8 weeks only the outer surfaces of wood blocks were selectively delignified. The percentages of weight loss obtained after 4, 8, and 12 weeks showed that decay occurred at a relatively constant rate. Selectively delignified wood could be identified by using scanning electron microscopy only when lignin had been extensively removed from cell walls.
X. frustulatus
was able to form pockets of delignified wood throughout blocks after 12 weeks.
Cloning and Expression of an Insecticidal k-73 Type Crystal Protein Gene from
Bacillus thuringiensis
var.
kurstaki
into
Escherichia coli
Authors: McLinden James H. , Sabourin Josanne R. , Clark Burton D. , Gensler Diana R. , Workman Wesley E. , Dean Donald H.
Published: January 2020

A 75-kilobase plasmid from
Bacillus thuringiensis
var.
kurstaki
(HD-244) was associated with the k-73 type insecticidal crystal protein production by mating into
B. cereus
and subsequent curing of excess plasmids. This plasmid was partially digested with endonuclease R ·
Sau
3A and the fragments were cloned into
Escherichia coli
(HB101) on vector pBR322. Candidate clones were screened for plasmid vectors which contained the expected insert size (at least 3 kilobases) and then with an enzyme-linked immunosorbent assay, using antisera prepared against electrophoretically purified, solubilized insecticidal crystal protein of 130,000 daltons. Several positive clones were isolated and were analyzed for expression, toxicity, and genetic content by restriction enzyme analysis. Electrophoretic transfer blots of proteins from a candidate
E. coli
clone, analyzed by enzyme-linked immunosorbent assay, demonstrated a predominant cross-reacting protein of about 140,000 daltons. Ouchterlony analysis also showed a single precipitin band. Extensive bioassays with
Manduca sexta
larvae revealed that the
E. coli
clones make toxin with a specific activity (50% lethal dose per microgram of cross-reacting protein) equivalent to that of the parental
B. thuringiensis
strain or a
B. cereus
trancipient carrying the toxin-encoding, 75-kilobase plasmid.
Effects of antimicrobial agents fed to chickens on some gram-negative enteric bacilli
Authors: Mamber S W , Katz S E
Published: January 2020

Total and antimicrobial agent-resistant aerobic and facultative anaerobic gram-negative enteric bacilli in fecal samples of broiler chickens fed growth-promotional levels of antimicrobial agents were determined quantitatively. Two 8-week studies were conducted utilizing groups of chickens fed antimicrobial-supplemented rations; the second study involved feed "pasteurization" as a means of minimizing colonization from the feed. Dilution/spread-plating/replica-plating techniques on selective media were used to obtain counts of total organisms and those resistant to tetracycline, chloramphenicol, streptomycin, ampicillin, or kanamycin. The predominant aerobic and facultative anaerobic gram-negative organism was Escherichia coli, which was detected in all samples at levels ranging from 10(5) to over 10(10) CFU/g of feces. Less common were Proteus mirabilis, Klebsiella pneumoniae, and Pseudomonas sp., which varied in occurrence and levels from group to group (range, less than 10(3) to 10(8) CFU/g). Resistance to all antimicrobials (except chloramphenicol in E. coli) was commonly observed at incidences exceeding 10(3) CFU/g in the total populations. Colonization of the chickens' intestinal tracts by susceptible and resistant strains of E. coli, K. pneumoniae, and Pseudomonas sp. appeared to result from their presence in the environment of the newly hatched chickens. Ration pasteurization did affect P. mirabilis, which appeared to colonize from the feed. The results suggest that colonization by, and proliferation of, antimicrobial-resistant aerobic and facultative anaerobic gram-negative enteric bacilli in chicken intestinal tracts may be less dependent on selection through antimicrobial supplementation of the ration than on their prevalence in environments from which they can colonize newborns.
Trichothecene Production in Liquid Stationary Cultures of
Fusarium tricinctum
NRRL 3299 (Synonym:
F. sporotrichioides
): Comparison of Quantitative Brine Shrimp Assay with Physicochemical Analysis
Authors: Bergers W. W. A. , van der Stap J. G. M. M. , Kientz C. E.
Published: January 2020

Stationary liquid cultures of
Fusarium tricinctum
NRRL 3299 (synonym:
F. sporotrichioides
) produce T-2 toxin, neosolaniol, diacetoxyscirpenol, and HT-2 toxin when cultured on peptone-enriched Czapek Dox medium. At 15 and 27°C, maximum T-2 toxin yield (265 and 50 μg/ml) was found after 10 to 14 and 7 days, respectively. The T-2 toxin in the culture medium was metabolized rapidly at 27°C and slowly at 15°C. Addition of 0.025% (wt/vol) sorbic acid to the medium resulted in an increased production of trichothecenes at 15°C (400 μg of T-2 per ml after 14 days). Trichothecenes in the culture liquid were determined by the brine shrimp bioassay and physicochemical analysis. The brine shrimp assay was improved by using modern bioassay equipment, including tissue culture trays and multipipettes, and by a standardized approach with positive and negative controls. The physicochemical analysis was based on adsorption of the trichothecenes onto Amberlite XAD-2 columns, derivatization with trifluoroacetic anhydride followed by capillary gas chromatography, and identification by mass spectrometry (as many as 17 trichothecenes were detected in the culture medium). The brine shrimp assay offers an interesting monitoring system for the quantitation of T-2 toxin and should be useful for studies on production of this toxin in culture. Specific information on less toxic trichothecenes, however, requires a more time-consuming chemical analysis.
Recovery of Saccharomyces cerevisiae from ethanol-induced growth inhibition
Authors: Walker-Caprioglio H M , Rodriguez R J , Parks L W
Published: January 2020

Ethanol caused altered mobility of the lipophilic probe 1,6-diphenyl-1,3,5-hexatriene in plasma membrane preparations of Saccharomyces cerevisiae. Because lipids had been shown to protect yeast cells against ethanol toxicity, sterols, fatty acids, proteins, and combinations of these were tested; however, protection from growth inhibition was not seen. Ethanol-induced, prolonged lag periods and diminished growth rates in S. cerevisiae were reduced by an autoconditioning of the medium by the inoculum.
Transport and processing of staphylococcal enterotoxin A
Authors: Christianson K K , Tweten R K , Iandolo J J
Published: January 2020

A larger-molecular-weight precursor of enterotoxin A was found in membranes of Staphylococcus aureus and was shown to be the kinetic precursor to the extracellular form of the toxin. Subcellular fractionation revealed that mature enterotoxin A was transiently associated with the cell wall before being released to the extracellular environment.
Response of
Sesbania grandiflora
to Inoculation of Soil with Vesicular-Arbuscular Mycorrhizal Fungi
Authors: Habte Mitiku , Aziz Taufiqul
Published: January 2020

A greenhouse experiment was conducted to determine the influence of two tropical isolates of
Glomus fasciculatum
and
Glomus mosseae
on the nutrient uptake and growth of
Sesbania grandiflora.
Inoculation of sterile soil with the fungi significantly improved growth and nutrient uptake by
S. grandiflora
, but the response of the legume was markedly better when the soil was inoculated with
G. fasciculatum
than when it was inoculated with
G. mosseae.
Nutrient uptake and growth of
S. grandiflora
in nonsterile soil was also significantly stimulated by inoculation, but the legume did not respond differently to the two endophytes under this condition.
Survival of Saccharomyces cerevisiae Y5 during starvation in the presence of osmotic supports
Authors: Peled O N
Published: January 2020

The viability of starved or dying Saccharomyces cerevisiae Y5 cells was extended for up to 1,500 h by adding osmotic supports (0.6 M sorbitol or mannitol) to the starvation media. Replacement of these polyols with 0.3 M KCl, 0.5 M MgSO4, or 0.2 M MgCl2 postponed the death of cells incubated in N-free medium, but accelerated it in distilled water.
Production and Regeneration of
Thiobacillus ferrooxidans
Spheroplasts
Authors: Barros M. E. C. , Rawlings D. E. , Woods D. R.
Published: January 2020

We investigated the production and regeneration of
Thiobacillus ferrooxidans
spheroplasts. Regeneration frequencies of up to 90% reversion were obtained. Attempts to transform
T. ferrooxidans
spheroplasts with a recombinant
T. ferrooxidans
plasmid were unsuccessful.
Serotypes of Vibrio parahaemolyticus isolates from hydrobiologically dissimilar aquatic environments
Authors: Nair G B , Sarkar B L , Abraham M , Pal S C
Published: January 2020

Serological analysis of the O and K antigens was performed on 324 isolates of Vibrio parahaemolyticus obtained from three hydrobiologically dissimilar aquatic environments. Only 50.9% of the strains could be serotyped. The largest number of untypable strains and the lowest serological diversity were observed from the freshwater collection. Three serotypes, O2:K28, O5:K17, and O2:K3, dominated among all biotopes. There appears to be some distinction between serotypes of environmental and clinical origins.
Stem and Root Nodulation in
Aeschynomene
spp
Authors: Alazard D.
Published: January 2020

Nodulation ability of 15
Rhizobium
strains isolated from root and stem nodules of tropical
Aeschynomene
species was studied on 20 different
Aeschynomene
species and four other legumes—
Arachis hypogaea, Stylosanthes guianensis, Macroptilium atropurpureum
, and
Sesbania rostrata.
The results of this investigation showed that
Aeschynomene
species could be divided into three groups according to the cross-inoculation group concept.
Starch-Ampicillin Agar for the Quantitative Detection of
Aeromonas hydrophila
Authors: Palumbo Samuel A. , Maxino Felicisima , Williams Aaron C. , Buchanan Robert L. , Thayer Donald W.
Published: January 2020

Interest in
Aeromonas hydrophila
as a food-borne and human pathogen is increasing. Isolation media from the clinical laboratory were evaluated for food use and either did not give quantitative recovery of
A. hydrophila
or did not permit ready differentiation of
A. hydrophila
from the background microflora. A new medium was developed which permitted quantitative recovery of
A. hydrophila
from foods. The medium consisted of phenol red agar base (Difco Laboratories), soluble starch (10 g/liter), and ampicillin (10 mg/liter). All foods surveyed contained
A. hydrophila.
Foods sampled included red meats, chicken, raw milk, and seafood (fish, shrimp, scallops, crab, and oysters). The count of
A. hydrophila
at the time of purchase ranged from 1 � 10
2
/g (lower limit of detection) to 5 � 10
5
/g. In most instances, the count of
A. hydrophila
increased during 1 week of storage at 5�C. The starch-ampicillin agar developed permitted rapid quantitative recovery of
A. hydrophila
from foods in the presence of very large numbers of competing microflora.
Significance of Extracellular Protease for Growth of a Heterotrophic Bacterium,
Aeromonas salmonicida
Authors: Sakai D. K.
Published: January 2020

The role of protease produced by a heterotrophic bacterium during growth was investigated with
Aeromonas salmonicida
, the pathogen of fish furunculosis, strain A-7301 and its protease-deficient mutant NTG-1 induced by mutagenesis. Strain A-7301 produced extracellular protease in a mixed amino acid medium (composed of Gly, Ala, Val, Ile, Leu, Thr, Ser, Cys, Met, Phe, Tyr, Lys, Arg, Pro, His, Try, Asp, Asn, Glu, and Gln at equal concentrations of 0.1 g/liter). Its multiplication rate was limited by the amounts of amino acids present, whereas strain NTG-1 showed no protease production despite considerable growth similar to that of A-7301. There was no difference between A-7301 and NTG-1 in amino acid requirements for growth, and seven amino acids (Gly, Ala, Val, Thr, Cys, Met, and His) were found to be indispensable. A defined level of the mixed amino acids (0.4 to 0.5 g/liter) was needed for A-7301 to initiate a large production of protease. Neither of the strains grew well in a casein medium, to which no amino acids were added. However, when a protease fraction obtained from extracellular products of A-7301 by DEAE-cellulose column chromatography was added, NTG-1 successfully reproduced in the casein medium. These results indicate that the extracellular protease plays an important role in supplying
A. salmonicida
cells with available amino acids as nutrients and that higher growth is closely associated with protease production which stimulates further reproduction.
Pyrazines Responsible for the Potatolike Odor Produced by Some
Serratia
and
Cedecea
Strains
Authors: Gallois Annie , Grimont Patrick A. D.
Published: January 2020

The pyrazines responsible for the potatolike odor produced by some
Serratia
and
Cedecea
cultures were identified by gas-liquid chromatography (with flame ionization and thermoionic ionization detectors) and mass spectrometry. Alkylpyrazines were produced by the six strains studied irrespective of their odors. The major alkyl-methoxypyrazine produced by
Cedecea davisae
was 3-
sec
-butyl-2-methoxypyrazine, and that produced by odoriferous
Serratia
strains (
S. rubidaea, S. odorifera
, and
S. ficaria
) was 3-isopropyl-2-methoxy-5-methyl-pyrazine. Other pyrazines produced by some strains were 3-isopropyl-2-methoxypyrazine, 3-isobutyl-2-methoxypyrazine, 3-
sec
-butyl-2-methoxy-5-methylpyrazine, and 3-isobutyl-2-methoxy-6-methylpyrazine. Some of these pyrazines had not previously been found as natural products or to be produced by bacteria.