bluuebunny/crossref_metadata_2025 huggingface dataset:
Bacterial growth in ground beef prepared from electrically stimulated and nonstimulated muscles
Authors: Butler J L , Smith G C , Savell J W , Vanderzant C
Published: January 2020

Ground beef samples prepared from electrically stimulated and nonstimulated biceps femoris and infraspinatus muscles were inoculated with Lactobacillus sp., Pseudomonas sp., Acinetobacter sp., or a mixture of Lactobacillus spp., Pseudomonas spp., Acinetobacter spp., Moraxella sp., Microbacterium thermosphactum, and Erwinia herbicola. There were no significant differences in growth of various bacteria in ground beef made from electrically stimulated and nonstimulated muscles.
Procedure for recovery of enteroviruses from the Japanese cockle Tapes japonica
Authors: Johnson K M , Cooper R C , Straube D C
Published: January 2020

The most likely shellfish to be harvested if sportfishing is reinstated in San Francisco Bay is the Japanese cockle Tapes japonica. The virus levels present in these shellfish are unknown and need to be evaluated before the shellfish beds are open. Towards this end, a procedure for recovering and concentrating enteric viruses from these clams has been evaluated. Effective elution of poliovirus from clam tissues was found to occur with pH 9.5 glycine-buffered saline rather than with the pH 7.5 fluid utilized by other investigators on oysters. Poliovirus desorption was combined with Cat-Floc clarification to remove cytotoxicity from clam tissue homogenates. For assay purpose, viruses were concentrated by mixing the glycine supernatant with a beef extract solution, lowering the pH, and suspending the resulting floc in a small volume of phosphate buffer. This simple technique successfully recovered an average of 73% of the poliovirus added to clam homogenates at levels of 93 and 660 plaque-forming units per 100 g. Coxsackievirus B2 was isolated from clams exposed to raw sewage.
Metabolism of 4-Chloronitrobenzene by the Yeast
Rhodosporidium
sp
Authors: Corbett Michael D. , Corbett Bernadette R.
Published: January 2020

The yeast
Rhodosporidium
sp. metabolized 4-chloronitrobenzene by a reductive pathway to give 4-chloroacetanilide and 4-chloro-2-hydroxyacetanilide as the major final metabolites. The intermediate production of 4-chloronitrosobenzene, 4-chlorophenylhydroxylamine, and 4-chloroaniline was demonstrated by high-pressure liquid chromatography. Additional studies with selected metabolites established that the metabolite 4-chloro-2-hydroxyacetanilide was produced by an initial Bamberger rearrangement of the hydroxylamine metabolite, followed by acetylation. Direct C hydroxylation of the aromatic ring was not observed in this species. No hydroxamic acid production was detected, even though significant concentrations of the nitroso and hydroxylamine precursors to this functional group were observed.
Characterization of the cecal bacteria of normal pigs
Authors: Robinson I M , Allison M J , Bucklin J A
Published: January 2020

One hundred ninety-two isolates from cecal contents of three normal weaned pigs were obtained by means of anaerobic roll tube methods and were characterized. Seventy-eight percent of the isolates were gram-negative. The most numerous species isolated from each of the pigs was Bacteroides ruminicola. This species accounted for 35% of the isolates that were characterized, and Selenomonas ruminantium accounted for 21% of the isolates. Other gram-negative bacteria isolated from all three pigs were Butyrivibrio fibrisolvens (6.0%) and Bacteroides uniformis (3.0%); predominant gram-positive isolates were Lactobacillus acidophilus (7.6%), Peptostreptococcus productus (3.0%), and Eubacterium aerofaciens (2.5%). The other 42 isolates were placed in 14 other species, and 5 additional isolates that did not fit well into existing species were not placed taxonomically. Fifteen of the isolates (representing nine species) produced urease.
Characterization of Extracellular β-
d
-Galactosidase from
Fusarium moniliforme
Grown in Whey
Authors: Macris B. J. , Markakis P.
Published: January 2020

Extracellular lactase (β-
d
-galactosidase, EC 3.2.1.23) was prepared as an ethanol precipitate from a culture of
Fusarium moniliforme
grown on whey. The enzyme functioned optimally at pH 3.8 to 5.0 and at 50 to 60°C on both
o
-nitrophenyl-β-
d
-galactopyranoside (ONPG) and lactose. The activation energy of the enzymic hydrolysis of ONPG and lactose in the range of 20 to 55°C was 8,500 and 7,200 cal (ca. 3.57 × 10
4
and 3.02 × 10
4
J)/mol, respectively. The

K
m

values were 4.4 and 12.4 mM for ONPG and lactose, respectively. At optimum pH, the enzyme lost half of its activity when it was heated at 50°C for 6 h; at the same pH, the loss was only 5% when the enzyme was heated at 37°C for 6 h. At optimum conditions, 50% of the lactose in whey was hydrolyzed by 10 U of this enzyme in 50 h.
Mutants of Saccharomyces cerevisiae and Candida utilis with increased susceptibility to digestive enzymes
Authors: Mehta R D , Gregory K F
Published: January 2020

Mutants of Candida utilis and a haploid strain of Saccharomyces cerevisiae were isolated, after ultraviolet light mutagenesis, which had increased sensitivities to snail gut enzymes (ses). Three of the five S. cerevisiae mutants tested had increased sensitivities to porcine pepsin, all were more susceptible to a sequential treatment with pepsin, lipase, peptidase, and trypsin, four were sensitive to osmotic shock, and two had increased glucan/mannan ratios in their cell walls. All combinations of mutants showed positive complementation in heterozygous diploids, although complementation between one pair, which had the same phenotype, was incomplete, indicating that four to five different cistrons were involved. All mutations were found to be recessive. Haploid strains bearing pairs of ses mutations were not markedly more sensitive to mammalian digestive enzymes than strains with single mutations. Rat-feeding experiments with three mutants and the parental strains indicated that the protein was efficiently utilized in all cases. Net protein ratios for the two mutants of S. cerevisiae tested were slightly higher than that for their parent, but the differences were of marginal significance.
Effect of solar radiation and predacious microorganisms on survival of fecal and other bacteria
Authors: McCambridge J , McMeekin T A
Published: January 2020

The effect of solar radiation and predacious microorganisms on the survival of bacteria of fecal and plant origin was studied. The decline in the numbers of Escherichia coli cells in estuarine water samples was found to be significantly greater in the presence of both naturally occurring microbial predators and solar radiation than when each of these factors was acting independently. The effect of solar radiation on microbial predators was negligible, whereas the susceptibility of bacteria to light-induced decay varied from one organism to another, as follows: Klebsiella pneumoniae greater than E. coli greater than Salmonella typhimurium, Streptococcus faecium, Enterobacter aerogenes, Erwinia herbicola.
Derivation of Aromatic Amino Acid Mutants from a Methanol-Utilizing Yeast,
Hansenula polymorpha
Authors: Denenu Emmanuel O. , Demain Arnold L.
Published: January 2020

Three classes of mutants, deregulated to enhance the flow of aromatic intermediates through the tryptophan biosynthetic branch, were obtained. 5-Fluorotryptophan, an antimetabolite of tryptophan, was employed to obtain one class of deregulated mutants. By sequential resistance development, three resistant mutants were isolated.
Hansenula polymorpha
strains showed greater sensitivity to 5-fluorotryptophan when growing on methanol than when growing on glucose. Yeast extract stimulated the production of total indole metabolites (indoles) by wild-type and mutant strains, with each 5-fluorotryptophan mutant producing higher amounts of these metabolites than its predecessor. Two other mutant classes were isolated: (i) a mutant resistant to anthranilate (an inhibitory intermediate in the tryptophan biosynthetic branch) and (ii) a phenylalanine-plus-tyrosine bradytroph. Each of these produced a higher extracellular titer of total indoles than its immediate parent. With respect to the overproduction of indoles, resistance to 5-fluorotryptophan was a more useful selection method than were anthranilate resistance and phenylalanine-plus-tyrosine bradytrophy.
Membrane filter method for enumerating Escherichia coli
Authors: Dufour A P , Strickland E R , Cabelli V J
Published: January 2020

A membrane filter procedure for enumerating Escherichia coli was developed and evaluated. The method quantifies E. coli within 24 h without requiring subculture and identification of isolates. It incorporates a primary selective-differential medium for gram-negative, lactose-fermenting bacteria; resuscitation of weakened organisms by incubation for 2 h at 35 degrees C before incubation at 44.5 degrees C for 18 to 22 h; and an in situ urease test to differentiate E. coli from other thermotolerant, lactose-positive organisms. The recovery of E. coli from marine, estuarine, and freshwater samples exceeded 90%. Of the presumptively positive colonies, 91% were verified as E. coli. Less than 1% of all of the verified E. coli colonies failed to react typically.
Methanol Inhibition in Continuous Culture of
Hansenula polymorpha
Authors: Swartz James R. , Cooney Charles L.
Published: January 2020

Growth inhibition of
Hansenula polymorpha
DL-1 by methanol, formaldehyde, formate, and formic acid was examined to determine the causes of unstable behavior observed during continuous cultures on methanol. The much greater inhibition of growth by formic acid than by formate and the effect of formic acid excretion and assimilation on pH helped to explain culture dynamics observed after transitory oxygen limitations. Oxygen limitation caused by temporary reduction of agitation in a continuous fermentation caused methanol to accumulate to inhibitory concentrations. Immediately after resumption of agitation, formic acid was produced and caused culture inhibition. To ensure the stability of
H. polymorpha
in continuous culture, it was therefore necessary to prevent transient methanol accumulation.
Fermentative Conversion of Cellulose to Acetic Acid and Cellulolytic Enzyme Production by a Bacterial Mixed Culture Obtained from Sewage Sludge
Authors: Khan A. W. , Wall Duncan , van den Berg L.
Published: January 2020

A simple procedure that uses a cellulose-enriched culture started from sewage sludge was developed for producing cellulolytic enzymes and converting cellulose to acetic acid rather than CH
4
and CO
2
. In this procedure, the culture which converts cellulose to CH
4
and CO
2
was mixed with a synthetic medium and cellulose and heated to 80°C for 15 min before incubation. The end products formed were acetic acid, propionic acid, CO
2
, and traces of ethanol and H
2
. Supernatants from 6- to 10-day-old cultures contained 16 to 36 mM acetic acid. Cellulolytic enzymes in the supernatant were stable at 2°C under aerobic conditions for up to 4 weeks and had the ability to hydrolyze carboxymethyl cellulose, a microcystalline cellulose, cellobiose, xylan, and filter paper to reducing sugars.
Carbohydrate Fermentation by
Streptococcus cremoris
and
Streptococcus lactis
Growing in Agar Gels
Authors: Thomas Terence D. , Turner Keith W.
Published: January 2020

When lactic streptococci were embedded in agar gels and incubated at 30°C, the end products of carbohydrate fermentation depended on the initial cell density, which determined the subsequent distribution and size of colonies in the gel. With high initial cell densities, microcolonies formed close together and lactose and glucose were converted almost entirely to lactate. However, inoculation with a small number of cells, which then grew to form widely spaced and comparatively large colonies, resulted in up to 30% diversion of end product, usually to formate, ethanol, and acetate. In these “low-colony-density” gel cultures, the initial rate of fermentation was exponential and only lactate was formed. However, this rate then became linear and fermentation became progressively more heterolactic.
Streptococcus lactis
ML
8
was the only strain among the 10 tested which remained homolactic. Incubation at temperatures either above or below the optimum for growth and metabolism decreased the diversion to end products other than lactate. The change from homo- to heterolactic fermentation appears to be caused by carbohydrate depletion in the vicinity of the colony, so that fermentation is then limited by the diffusion of substrate. Growth of cells on gel surfaces exposed to air resulted in up to 40% diversion of end product from lactate, mainly to CO
2
, acetoin, 2,3-butanediol, and acetate. Six of the 12
Streptococcus cremoris
strains tested remained homolactic under these aerobic conditions, whereas all 8 of the
S. lactis
strains tested, including ML
8
, were heterolactic.
Seasonal Rates of Methane Oxidation in Anoxic Marine Sediments
Authors: Iversen Niels , Blackburn T. Henry
Published: January 2020

Methane concentrations and rates of methane oxidation were measured in intact sediment cores from an inshore marine sediment at Jutland, Denmark. The rates of methane oxidation, determined by the appearance of
14
CO
2
from injected
14
CH
4
, varied with sediment depth and season. Most methane oxidation was anoxic, but oxygen may have contributed to methane oxidation at the sediment surface. Cumulative rates (0- to 12-cm depth) for methane oxidation at Kysing Fjord were 3.34, 3.48, 8.60, and 17.04 μmol m
−2
day
−1
for April (4°C), May (13°C), July (17°C), and August (21°C), respectively. If all of the methane was oxidized by sulfate, it would account for only 0.01 to 0.06% of the sulfate reduction. The data indicate that methane was produced, in addition to being oxidized, in the 0- to 18-cm sediment stratum.
Composting Process Control Based on Interaction Between Microbial Heat Output and Temperature
Authors: MacGregor S. T. , Miller F. C. , Psarianos K. M. , Finstein M. S.
Published: January 2020

Rational composting process control involves the interrelated factors of heat output, temperature, ventilation, and water removal. The heat is released microbially at the expense of organic material; temperature is an effect and, because it is a determinant of microbial activity, it is also a cause of heat output; ventilation supplies oxygen and removes heat, mainly through the vaporization of water; water removal results from heat removal. These relationships were implemented in a field-scale process of static-pile configuration, using a mixture of sewage sludge and wood chips. Heat removal was matched to heat output through a temperature feedback control system, thereby maintaining biologically favorable temperatures. The observations indicate that fundamentally there are two kinds of composting systems: those that are and those that are not temperature self-limiting. The self-limiting system reaches inhibitive temperatures (>60°C) which debilitate the microbial community, suppressing decomposition, heat output, and water removal. In contrast, non-self-limiting temperatures (<60°C) support a robust community, promoting decomposition, heat output, and water removal.
Bacterial survival in a dilute environment
Authors: Sjogren R E , Gibson M J
Published: January 2020

Bacteria were isolated from lake water, and their ability to remain viable in a dilute, nutrient-deficient environment was tested by a method that permits suspension of test bacteria between two appressed microporous membranes in an aqueous environment. This approach permitted separation of the lake isolates into two categories. Members of the tribe Klebsielleae were shown to have a prolonged survival rate of 40% or better after 24 h, whereas nonsurvivors were not viable for much longer than 24 h. These nonsurvivors belonged to the genera Acinetobacter, Aeromonas, Alcaligenes, Erwinia, Escherichia, Flavobacterium, and Pseudomonas. Differences in ribonuclease and adenosine triphosphatase levels between Escherichia coli (nonsurvivor) and Klebsiella (survivor) cells were detected. At pH 7.5, stressed E. coli cells contained 14% of the adenosine triphosphatase activity detected in the control, whereas at pH 5.5, in the presence of calcium ions, these same cells contained 50% of the control adenosine triphosphatase levels. At pH 7.2, E. coli cells were strongly inhibited by an adenosine triphosphatase inhibitor, bathophenanthroline (88%); oligomycin (64%); and the proton ionophore carbonyl- cyanide-m-chlorophenyl hydrazone (67%). Both sodium azide and valinomycin were only moderately inhibitory (15 and 28%, respectively). Although the ability to scavenge internal endogenous reserves seems important, we postulate that certain enteric bacteria are capable of utilizing acidic conditions (pH 5.5) as an electrochemical gradient to generate necessary high-energy intermediates for prolongation of survival beyond that possible in environments of near-neutraL pH.
Ethanol Production by Thermophilic Bacteria: Fermentation of Cellulosic Substrates by Cocultures of
Clostridium thermocellum
and
Clostridium thermohydrosulfuricum
Authors: Ng Thomas K. , Ben-Bassat Arie , Zeikus J. G.
Published: January 2020

The fermentation of various saccharides derived from cellulosic biomass to ethanol was examined in mono- and cocultures of
Clostridium thermocellum
strain LQRI and
C. thermohydrosulfuricum
strain 39E.
C. thermohydrosulfuricum
fermented glucose, cellobiose, and xylose, but not cellulose or xylan, and yielded ethanol/acetate ratios of >7.0.
C. thermocellum
fermented a variety of cellulosic substrates, glucose, and cellobiose, but not xylan or xylose, and yielded ethanol/acetate ratios of ∼1.0. At nonlimiting cellulosic substrate concentrations (∼1%),
C. thermocellum
cellulase hydrolysis products accumulated during monoculture fermentation of Solka Floc cellulose and included glucose, cellobiose, xylose, and xylobiose. A stable coculture that contained nearly equal numbers of
C. thermocellum
and
C. thermohydrosulfuricum
was established that fermented a variety of cellulosic substrates, and the ethanol yield observed was twofold higher than in
C. thermocellum
monoculture fermentations. The metabolic basis for the enhanced fermentation effectiveness of the coculture on Solka Floc cellulose included: the ability of
C. thermocellum
cellulase to hydrolyze α-cellulose and hemicellulose; the enhanced utilization of mono- and disaccharides by
C. thermohydrosulfuricum
; increased cellulose consumption; threefold increase in the ethanol production rate; and twofold decrease in the acetate production rate. The coculture actively fermented MN300 cellulose, Avicel, Solka Floc, SO
2
-treated wood, and steam-exploded wood. The highest ethanol yield obtained was 1.8 mol of ethanol per mol of anhydroglucose unit in MN300 cellulose.
Molecular Cloning of Genes for Cellobiose Utilization and Their Expression in
Escherichia coli
Authors: Armentrout Richard W. , Brown Ronald D.
Published: January 2020

The genes for cellobiose utilization in
Escherichia adecarboxylata
were cloned by using recombinant deoxyribonucleic acid techniques and transferred to
Escherichia coli
. Preliminary analysis of the β-glucosidase activity expressed in these host cells indicated that the enzyme is membrane bound and required magnesium ions, phosphate ions, and heat-stable, non-dialyzable factors from the bacterial cytoplasm.
Macrocyclic trichothecene toxins produced by a strain of Stachybotrys atra from Hungary
Authors: Harrach B , Mirocha C J , Pathre S V , Palyusik M
Published: January 2020

A strain of Stachybotrys atra isolated from a field case of stachybotryotoxicosis in Hungary was cultured in Hungary. All of the compounds toxic to brine shrimp were separated from the culture extract by solvent partition, column chromatography, and preparative thin-layer chromatography. Two of the toxic compounds were identified as verrucarin J and satratoxin H by comparison with pure standards resolved by high-pressure liquid chromatography and characterized by mass spectrometry. Two other toxic components were identified as roriden E and satratoxin G on the basis of their mass spectra. The fifth toxic compound was identified as a macrocyclic trichothecene based on the following findings: a positive 4-(p-nitrobenzyl)pyridine color reaction, hydrolysis resulting in verrucarol verified by combined gas chromatography-mass spectrometry, and a characteristic trichothecene proton-nuclear magnetic resonance spectrum. This macrocyclic trichothecene has a molecular ion (528) identical to satratoxin H, and its mass spectrum is similar; however, its Rf value on Silica Gel G differs.
Effect of Manual Brush Cleaning on Biomass and Community Structure of Microfouling Film Formed on Aluminum and Titanium Surfaces Exposed to Rapidly Flowing Seawater
Authors: Nickels Janet S. , Bobbie Ronald J. , Lott Dan F. , Martz Robert F. , Benson Peter H. , White David C.
Published: January 2020

Metals exposed to rapidly flowing seawater are fouled by microbes that increase heat transfer resistance. In this study, results of biochemical test methods quantitatively relating the biomass and community structure of the microfouling film on aluminum and titanium to heat transfer resistance across the metal surface during three cycles of free fouling and manual brushing showed that cleaning accelerates the rate of fouling measured as the loss of heat transfer efficiency and as microfouling film biomass. The results also showed that the rate of fouling, measured as an increase in heat transfer resistance, is faster on titanium than on aluminum but that the titanium surface is more readily cleaned. In three cycles of free fouling and cleaning with a stiff-bristle nylon brush, the free-fouling communities re-forming on aluminum became enriched in bacteria containing short-branched fatty acids as the cycling progressed. The free-fouling community on titanium revealed an increasingly diverse morphology under scanning electron microscopy that was enriched in a portion of the microeucaryotes. Brushing removed most of the biomass, but left a residual community that was relatively enriched in a portion of the bacterial assembly containing cyclopropane fatty acids on aluminum and in a more diverse community on the titanium surface. The residual communities left after cleaning of titanium revealed an increase in bacteria with short-branched fatty acids and in microeucaryotes as cleaning continued. No significant changes occurred in the residual microbial community structure left on aluminum with cleaning; it was, again, less diverse than that remaining on titanium. The residual communities secreted a twofold-larger amount of extracellular polymer, measured as the ratio of total organic carbon to lipid phosphate, than did the free-fouling community on both surfaces.
Growth Characteristics, Bile Sensitivity, and Freeze Damage in Colonial Variants of
Lactobacillus acidophilus
Authors: Klaenhammer T. R. , Kleeman E. G.
Published: January 2020

Rough (R) and smooth (S) colonial variants were isolated from a heterogeneous culture of
Lactobacillus acidophilus
RL8K. R and S types were stable upon repeated transfer on agar, but revertant colonies did appear after broth transfers. When propagated in commercial MRS broth, R and S cultures showed similar growth characteristics, and both cell types were insensitive to freezing and frozen storage at −20°C. Alternatively, during growth in scratch MRS broth, R cultures shifted to a reduced rate of growth during the late logarithmic phase. R cells grown under these conditions were susceptible to death by freezing and injury at −20°C. Microscopically, R cells were observed as long gram-positive rods with small nonstainable blebs protruding from the cell wall. In bile sensitivity studies of R and S cells plated on MRS agar plus oxgall, the S culture was resistant to 1% bile, whereas the R culture was sensitive to 0.6% bile. Differences in the bile resistance and freeze damage of R and S cells suggest that colonial and cellular morphologies are important considerations for the selection of
Lactobacillus
strains as dietary adjuncts and for the development of growth conditions for preparing frozen concentrated cultures from either cell type.
Distribution of
Clostridium botulinum
Around Fishing Areas of the Western Part of Indonesian Waters
Authors: Suhadi F. , Thayib S. S. , Sumarsono N.
Published: January 2020

A survey was carried out to determine the presence of
Clostridium botulinum
in samples of sediment and seafoods from the fishing areas of the western part of Indonesian waters. Among the 3,433 samples, 82 (2.4%) were positive for
C. botulinum.
Type E was not found.
Characteristics of environmental isolates of Legionella pneumophila
Authors: Orrison L H , Cherry W B , Fliermans C B , Dees S B , McDougal L K , Dodd D J
Published: January 2020

Thirty-eight cultures of Legionella pneumophila isolated from surface waters were characterized by their morphological, tinctorial, biochemical, and serological properties and by their ability to produce disease in guinea pigs. Their susceptibility to antimicrobial agents also was tested. When they were compared with clinical isolates, no important differences were found between cultures from the two sources. Sodium hippurate hydrolysis, gelatin liquefaction, pigment formation, and beta-lactamase and alkaline phosphatase activity were useful in differentiating the four described species of Legionella. Hydrolysis of diacetylfluorescein and the inability to reduce nitrate help to distinguish Legionella species from other gram-negative bacterial rods.
Effect of turbidity on chlorination efficiency and bacterial persistence in drinking water
Authors: LeChevallier M W , Evans T M , Seidler R J
Published: January 2020

To define interrelationships between elevated turbidities and the efficiency of chlorination in drinking water, experiments were performed to measure bacterial survival, chlorine demand, and interference with microbiological determinations. Experiments were conducted on the surface water supplies for communities which practice chlorination as the only treatment. Therefore, the conclusions of this study apply only to such systems. Results indicated that disinfection efficiency (log10 of the decrease in coliform numbers) was negatively correlated with turbidity and was influenced by season, chlorine demand of the samples, and the initial coliform level. Total organic carbon was found to be associated with turbidity and was shown to interfere with maintenance of a free chlorine residual by creating a chlorine demand. Interference with coliform detection in turbid waters could be demonstrated by the recovery of typical coliforms from apparently negative filters. The incidence of coliform masking in the membrane filter technique was found to increase as the turbidity of the chlorinated samples increased. the magnitude of coliform masking in the membrane filter technique increased from less than 1 coliform per 100 ml in water samples of less than 5 nephelometric turbidity units to greater than 1 coliform per 100 ml in water samples of greater than 5 nephelometric turbidity units. Statistical models were developed to predict the impact of turbidity on drinking water quality. The results justify maximum contaminant levels for turbidity in water entering a distribution system as stated in the National Primary Drinking Water Regulations of the Safe Drinking Water Act.
Carrageenan from
Eucheuma striatum
(Schmitz) in Media for Fungal and Yeast Cultures
Authors: Laserna E. C. , Uyenco F. , Epifanio E. , Veroy R. L. , Cajipe G. J. B.
Published: January 2020

Fungi and yeasts were cultivated on media prepared from
Eucheuma
carrageenan. The cultures were found to compare well with those grown on agar media.
Syntrophic Association by Cocultures of the Methanol- and CO
2
-H
2
-Utilizing Species
Eubacterium limosum
and Pectin-Fermenting
Lachnospira multiparus
During Growth in a Pectin Medium
Authors: Rode L. M. , Genthner B. R. Sharak , Bryant M. P.
Published: January 2020

Lachnospira multiparus
grew very well in an anaerobic 0.2% pectin medium, whereas
Eubacterium limosum
, which utilizes methanol, H
2
-CO
2
, and lactate, did not. Cocultures of the two species grew at a somewhat more rapid growth rate than did
L. multiparus
alone and almost doubled the amount of growth as measured by optical density. In model experiments with cultures transferred once a day with a 2-day retention time,
L. multiparus
produced mainly acetate, methanol, ethanol, formate, lactate, CO
2
, and H
2
from pectin. The coculture produced one-third more acetate, and butyrate and CO
2
were the only other significant end products. The results are discussed in relationship to microbial metabolic interactions and interspecies hydrogen transfer.
New waterborne bacteriophages active on Yersinia enterocolitica
Authors: Calvo C , Brault J , Alonso J M , Mollaret H H
Published: January 2020

Seven bacteriophages active on Yersinia enterocolitica (YE) were isolated from surface water samples collected in Granada, Spain. A comparison of the respective host ranges of these new phages and of reference phages used for YE phage typing showed that YE strains belonging to various phage types, grown at either 37 or 25 degrees C, expressed susceptibility to reference sewage water phages whereas susceptibility to new waterborne phages, as well as to reference phages from lysogenic YE, was only demonstrated in YE strains grown at 25 degrees C. A YE strain isolated by stool culture from a pig was lysogenic for a bacteriophage which behaved like waterborne phages and reference phages from lysogenic YE strains. The possibility that the isolation of waterborne bacteriophages might, in certain circumstances, reflect the presence of lysogenic YE was raised.
Serogrouping of motile Aeromonas species isolated from healthy and moribund fish
Authors: Leblanc D , Mittal K R , Olivier G , Lallier R
Published: January 2020

A total of 195 strains of motile Aeromonas isolated from fish were characterized as Aeromonas hydrophila and Aeromonas sobria. In view of the frequency of isolation and the importance of motile Aeromonas species as fish pathogens, a serological classificaton of these organisms was attempted. Antisera were prepared in rabbits against formalinized whole cell suspensions and against boiled cells of 12 different isolates. Seventy-six strains could be grouped by tube agglutination with whole cells as antigen and anti-whole cell antiserum. However, only 39 strains were typable with anti-O serum. Differentiation was made between heat-stable antigens and heat-labile antigens which did not block the O agglutination reaction. The same heat-labile antigen could be associated with different heat-stable particulate antigens, and a relationship was observed between the heat-stable particulate antigens and the virulence of A. hydrophila for fish. In addition to these two types of antigen, motile Aeromonas possessed heat-stable soluble antigens which could be detected by indirect hemagglutination. One strain seemed to possess various heat-stable soluble antigens; so far, however, it does not appear to be feasible to use these antigens for serology. Finally, we also observed cross-reactions between some A. hydrophila and A. sobria strains.
Novel metabolites from Penicillium crustosum, including penitrem E, a tremorgenic mycotoxin
Authors: Kyriakidis N , Waight E S , Day J B , Mantle P G
Published: January 2020

Two new indolic metabolites were isolated from Penicillium crustosum and separated from other penitrem mycotoxins by high-performance liquid chromatography. Penitrem D is a deoxy-penitrem A. Penitrem E is dechloro-penitrem A and was shown to be tremorgenic in mice, although it has only one-third of the activity of penitrem A. Roquefortine was also shown, for the first time, to be an important metabolic product of P. crustosum.
Heat sensitization of bacterial spores after exposure to ethidium bromide, acriflavine, or daunomycin
Authors: Hanlin J H , Cloutier M J , Slepecky R A
Published: January 2020

A 20-min exposure of 10(7) unmodified spores of either Bacillus subtilis NCTC 3610 (harvested from potato-dextrose agar plus manganese) or Bacillus megaterium ATCC 19213 (harvested from nutrient agar plus manganese) per ml to 5 microgram of ethidium bromide per ml did not kill the spores (recovered on TAM [thermoacidurans agar modified]-plus thymidine medium). However, in both cases, the ability to survive various heat treatments was reduced after exposure of the spores to ethidium bromide. With B. subtilis, a 10-min heat treatment at 85 degrees C of unexposed spores resulted in an 85% survival rate, whereas only 50% of the ethidium bromide-exposed spores survived. With B. megaterium similar results were obtained at 75 degrees C; 77% of the unexposed spores survived, whereas only 31% of the ethidium bromide-exposed spores survived. Similarly, a 10-min exposure of B. subtilis spores to 0.005 microgram of acriflavine per ml did not kill unheated spores; however, the ability of the spores to survive exposure at 85 degrees C for 10 min was reduced to 40%. After exposure to 10 microgram of daunomycin per ml, the survival rate was 35%. Binding studies with ethidium bromide showed strong binding to spores, but as yet, the site of binding is unknown.
Evaluation of Standard and Modified M-FC, MacConkey, and Teepol Media for Membrane Filtration Counting of Fecal Coliforms in Water
Authors: Grabow W. O. K. , Hilner C. A. , Coubrough P.
Published: January 2020

MacConkey agar, standard M-FC agar, M-FC agar without rosolic acid, M-FC agar with a resuscitation top layer, Teepol agar, and pads saturated with Teepol broth, were evaluated as growth media for membrane filtration counting of fecal coliform bacteria in water. In comparative tests on 312 samples of water from a wide variety of sources, including chlorinated effluents, M-FC agar without rosolic acid proved the medium of choice because it generally yielded the highest counts, was readily obtainable, easy to prepare and handle, and yielded clearly recognizable fecal coliform colonies. Identification of 1,139 fecal coliform isolates showed that fecal coliform tests cannot be used to enumerate
Escherichia coli
because the incidence of
E. coli
among fecal coliforms varied from an average of 51% for river water to 93% for an activated sludge effluent after chlorination. The incidence of
Klebsiella pneumoniae
among fecal coliforms varied from an average of 4% for the activated sludge effluent after chlorination to 32% for the river water. The advantages of a standard membrane filtration procedure for routine counting of fecal coliforms in water using M-FC agar without rosolic acid as growth medium, in the absence of preincubation or resuscitation steps, are outlined.
Comparison of Extracellular Cellulase Activities of
Clostridium thermocellum
LQRI and
Trichoderma reesei
QM9414
Authors: Ng Thomas K. , Zeikus J. G.
Published: January 2020

The crude extracellular cellulase of
Clostridium thermocellum
LQRI (virgin strain) was very active and solubilized microcrystalline cellulose at one-half the rate observed for the extracellular cellulase of
Trichoderma reesei
QM9414 (mutant strain).
C. thermocellum
cellulase activity differed considerably from that of
T. reesei
as follows: higher endoglucanase/exoglucanase activity ratio; absence of extracellular cellobiase or
β
-xylosidase activity; long-chain oligosaccharides instead of short-chain oligosaccharides as initial (15-min) hydrolytic products on microcrystalline cellulose; mainly cellobiose or xylobiose as long-term (24-h) hydrolysis products of Avicel and MN300 or xylan; and high activity and stability at 60 to 70°C. Under optimized reaction conditions, the kinetic properties (
V
max
, 0.4 μmol/min per mg of protein; energy of activation, 33 kJ; temperature coefficient, 1.8) of
C. thermocellum
cellulose-solubilizing activity were comparable to those reported for
T. reesei
, except that the dyed Avicel concentration at half-maximal velocity was twofold higher (182 μM). The cellulose-solubilizing activity of the two crude cellulases differed considerably in response to various enzyme inhibitors. Most notably, Ag
2+
and Hg
2+
effectively inhibited
C. thermocellum
but not
T. reesei
cellulase at <20 μM, whereas Ca
2+
, Mg
2+
, and Mn
2+
inhibited
T. reesei
but not
C. thermocellum
cellulase at >10 mM. Both enzymes were inhibited by Cu
2+
(>20 mM), Zn
2+
(>1.0 mM), and ethylene glycol-bis(
β
-aminoethyl ether)-
N,N
-tetraacetic acid (>10 mM).
T. reesei
but not
C. thermocellum
cellulose-solubilizing activity was 20% inhibited by glucose (73 mM) and cellobiose (29 mM). Both cellulases preferentially cleaved the internal glycosidic bonds of cellooligosaccharides. The overall rates of cellooligosaccharide degradation were higher for
T. reesei
than for
C. thermocellum
cellulase, except that the rates of conversion of cellohexaose to cellotriose were equivalent.
d
-Xylulose Fermentation to Ethanol by
Saccharomyces cerevisiae
Authors: Chiang Lin-Chang , Gong Cheng-Shung , Chen Li-Fu , Tsao George T.
Published: January 2020

We used commercial bakers' yeast (
Saccharomyces cerevisiae
) to study the conversion of
d
-xylulose to ethanol in the presence of
d
-xylose. The rate of ethanol production increased with an increase in yeast cell density. The optimal temperature for
d
-xylulose fermentation was 35°C, and the optimal pH range was 4 to 6. The fermentation of
d
-xylulose by yeast resulted in the production of ethanol as the major product; small amounts of xylitol and glycerol were also produced. The production of xylitol was influenced by pH as well as temperature. High pH values and low temperatures enhanced xylitol production. The rate of
d
-xylulose fermentation decreased when the production of ethanol yielded concentrations of 4% or more. The slow conversion rate of
d
-xylulose to ethanol was increased by increasing the yeast cell density. The overall production of ethanol from
d
-xylulose by yeast cells under optimal conditions was 90% of the theoretical yield.
Nutritional Regulation of Lignin Degradation by
Phanerochaete chrysosporium
Authors: Jeffries Thomas W. , Choi Suki , Kirk T. Kent
Published: January 2020

Previous studies have shown that a lignin-degrading system appears in cultures of the white rot fungus
Phanerochaete chrysosporium
in response to nitrogen starvation, apparently as part of secondary metabolism. We examined the influence of limiting carbohydrate, sulfur, or phosphorus and the effect of varying the concentrations of four trace metals, Ca
2+
, and Mg
2+
. Limitation of carbohydrate or sulfur but not limitation of phosphorus triggered ligninolytic activity. When only carbohydrate was limiting, supplementary carbohydrate caused a transient repression of activity. In carbohydrate-limited cultures, ligninolytic activity appeared when the supplied carbohydrate was depleted, and this activity was associated with a decrease in mycelial dry weight. The amount of lignin degraded depended on the amount of carbohydrate provided, which determined the amount of mycelium produced during primary growth. Carbohydrate-limited cultures synthesized only small amounts of the secondary metabolite veratryl alcohol compared with nitrogen-limited cultures.
l
-Glutamate sharply repressed ligninolytic activity in carbohydrate-starved cultures, but NH
4
+
did not. Ligninolytic activity was also triggered in cultures supplied with 37 μM sulfur as the only limiting nutrient. The balance of trace metals, Mg
2+
, and Ca
2+
was important for lignin degradation.
Microbial flora of in-use, display eye shadow testers and bacterial challenges of unused eye shadows
Authors: Dawson N L , Reinhardt D J
Published: January 2020

We surveyed 15 different brands of eye shadow on display for customer use in different retail stores for microbial contamination. This was the first reported microbial surveillance of in-use eye shadow display testers in retail establishments. Cultures were obtained at each retail store. Sterile dacron swabs were rolled and rubbed over the entire used surface of each shadow, and each inoculum was streaked onto the surfaces of blood agar plates. Of the 1,345 individual samples obtained, 67% were contaminated with one or more species of microorganisms representing the genera Staphylococcus, Micrococcus, Corynebacterium, Acinetobacter, Bacillus, and Moraxella. We also purchased two different brands of water-miscible eye shadows in replicate unit containers. Each brand was challenged separately with a few hundred to several thousand colony-forming units of Staphylococcus aureus, Pseudomonas aeruginosa, or Acinetobacter calcoaceticus. Both brands permitted growth of P. aeruginosa but not growth of S. aureus. A. calcoaceticus was inhibited after inoculation into one brand. With the other brand, the inoculum of Acinetobacter multiplied in one of the two different lots tested. This experimental challenge procedure can serve as a useful model system for studying the behavior of microbes in eye shadows and similar matrices.
Degradation of Softwood, Hardwood, and Grass Lignocelluloses by Two
Streptomyces
Strains
Authors: Antai Sylvester P. , Crawford Don L.
Published: January 2020

Two
Streptomyces
strains,
S. viridosporus
T7A and
S. setonii
75Vi2, were grown on softwood, hardwood, and grass lignocelluloses, and lignocellulose decomposition was followed by monitoring substrate weight loss, lignin loss, and carbohydrate loss over time. Results showed that both
Streptomyces
strains substantially degraded both the lignin and the carbohydrate components of each lignocellulose; however, these actinomycetes were more efficient decomposers of grass lignocelluloses than of hardwood or softwood lignocelluloses. In particular, these
Streptomyces
strains were more efficient decomposers of grass lignins than of hardwood or softwood lignins.
Microbial Changes in Sweet Sorghum (
Sorghum bicolor
) Juices
Authors: Daeschel Mark A. , Mundt J. Orvin , McCarty Ivon E.
Published: January 2020

Juice freshly expressed from
Sorghum bicolor
for making sweet sorghum syrup contained 10
8
microorganisms per ml. The dominant bacterium was
Leuconostoc mesenteroides
, followed by gram-negative rods. Lactobacilli, yeasts, and nonfecal coliform bacteria each comprised about 1% of the microbial population. Spoilage of juice, manifested by a sour odor, discoloration, and foaming, occurred between 5 and 12 h at ambient temperatures. Spoilage was correlated with a drop in pH from 4.9 to 4.5
L. mesenteroides
was the dominant spoiling agent at 20°C, and
Lactobacillus plantarum
was the dominant spoiling agent at 32°C, as determined by pure culture studies. Juice may be stored for 14 days at 4°C if promptly refrigerated.
Assessment of bifidobacteria as indicators of human fecal pollution
Authors: Resnick I G , Levin M A
Published: January 2020

The distribution of bifidobacteria in the environment has been examined by using YN-6 medium. Although feces of humans, chickens, cows, dogs, pigs, horses, cats, sheep, beavers, goats, and turkeys were examined, bifidobacteria were isolated only from the feces of humans and swine. The frequency and distribution of component species of human fecal isolates were as in isolates from raw sewage. Bifidobacterium longum and B. adolescentis were most often isolated and in the highest densities. The levels of bifidobacteria in raw sewage were in the range of 10(6) organisms/100 ml, and the effect of primary and secondary sewage treatment on the number of viable organisms present was not significant. High densities of bifidobacteria were found in all samples from septic tanks. It was found that bifidobacteria did not survive as well as Escherichia coli in either fresh or marine waters. The ratio of bifidobacteria to E. coli is an indication of the age and of the effectiveness of treatment of sewage effluent.
Microbial Transformation of Quercetin by
Bacillus cereus
Authors: Rao Koppaka V. , Weisner Nghe T.
Published: January 2020

Biotransformation of quercetin was examined with a number of bacterial cultures. In the presence of a bacterial culture (
Bacillus cereus
), quercetin was transformed into two crystalline products, identified as protocatechuic acid and quercetin-3-glucoside (isoquercitrin).
Mechanisms of sorbate inhibition of Bacillus cereus T and Clostridium botulinum 62A spore germination
Authors: Smoot L A , Pierson M D
Published: January 2020

The mechanism by which potassium sorbate inhibits Bacillus cereus T and Clostridium botulinum 62A spore germination was investigated. Spores of B. cereus T were germinated at 35 degrees C in 0.08 M sodium-potassium phosphate buffers (pH 5.7 and 6.7) containing various germinants (L-alanine, L-alpha-NH2-n-butyric acid, and inosine) and potassium sorbate. Spores of C. botulinum 62A were germinated in the same buffers but with 10 mM L-lactic acid, 20 mM sodium bicarbonate, L-alanine or L-cysteine, and potassium sorbate. Spore germination was monitored by optical density measurements at 600 nm and phase-contrast microscopy. Inhibition of B. cereus T spore germination was observed when 3,900 micrograms of potassium sorbate per ml was added at various time intervals during the first 2 min of spore exposure to the pH 5.7 germination medium. C. botulinum 62A spore germination was inhibited when 5,200 micrograms of potassium sorbate per ml was added during the first 30 min of spore exposure to the pH 5.7 medium. Potassium sorbate inhibition of germination was reversible for both B. cereus T and C. botulinum 62A spores. Potassium sorbate inhibition of B. cereus T spore germination induced by L-alanine and L-alpha-NH2-n-butyric acid was shown to be competitive in nature. Potassium sorbate was also a competitive inhibitor of L-alanine- and L-cysteine-induced germination of C. botulinum 62A spores.
Effects of Nickel, Cobalt, and Molybdenum on Performance of Methanogenic Fixed-Film Reactors
Authors: Murray William D. , van den Berg L.
Published: January 2020

The conversion of acetic acid to methane and carbon dioxide by a mixed methanogenic population from an anaerobic fixed-film digestor was stimulated by the addition of nickel (100 nM) and cobalt (50 nM) and especially by the addition of these elements in combination. Molybdenum addition (50 nM) was only slightly stimulatory when added in combination with both nickel and cobalt. The addition of these trace metals to anaerobic fixed-film digestors, which treat food processing waste, greatly enhanced reactor performance. Total gas and methane productions were increased 42%, greater volumes of waste could be effectively treated, and reactor residence time was shortened. However, the lag period for reactor start-up was not reduced. Tests showed that reactor performance was increased because trace nutrient addition allowed accumulation of a thicker methanogenic fixed film.
Microbiology of Wetwood: Importance of Pectin Degradation and
Clostridium
Species in Living Trees
Authors: Schink Bernhard , Ward James C. , Zeikus J. Gregory
Published: January 2020

Wetwood samples from standing trees of eastern cottonwood (
Populus deltoides
), black poplar (
Populus nigra
), and American elm (
Ulmus americana
) contained high numbers of aerobic and anaerobic pectin-degrading bacteria (10
4
to 10
6
cells per g of wood). High activity of polygalacturonate lyase (≤0.5 U/ml) was also detected in the fetid liquid that spurted from wetwood zones in the lower trunk when the trees were bored. A prevalent pectin-degrading obligately anaerobic bacterium isolated from these wetwoods was identified as
Clostridium butyricum
. Pectin decomposition by
C. butyricum
strain 4P1 was associated with an inducible polygalacturonate lyase and pectin methylesterase, the same types of pectinolytic activity expressed in the wetwood of these trees. The pH optimum of the extracellular polygalacturonate lyase was alkaline (near pH 8.5). In vitro tests with sapwood samples from a conifer (Douglas fir,
Pseudotsuga menziesii
) showed that tori in membranes of bordered pits are degraded by pure cultures of strain 4P1, polygalacturonate lyase enzyme preparations of strain 4P1, and mixed methanogenic cultures from the tree samples of wetwood. These results provide evidence that pectin in xylem tissue is actively degraded by
C. butyricum
strain 4P1 via polygalacturonate lyase activity. The importance of pectin degradation by bacteria, including
Clostridium
species, appears paramount in the formation and maintenance of the wetwood syndrome in certain living trees.