bluuebunny/crossref_metadata_2025 huggingface dataset:
Rapid Degradation of Isolated Lignins by
Phanerochaete chrysosporium
Authors: Ulmer Duane C. , Leisola Matti S. A. , Schmidt Brigitte H. , Fiechter Armin
Published: January 2020

Phanerochaete chrysosporium
degraded purified Kraft lignin, alkali-extracted and dioxane-extracted straw lignin, and lignosulfonates at a similar rate, producing small-molecular-weight (∼1,000) soluble products which comprised 25 to 35% of the original lignins. At concentrations of 1 g of lignin liter
−1
, 90 to 100% of the acid-insoluble Kraft, alkali straw, and dioxane straw lignins were degraded by 1 g of fungal mycelium liter
−1
within an active ligninolytic period of 2 to 3 days. Cultures with biomass concentrations as low as 0.16 g liter
−1
could also completely degrade 1 g of lignin liter
−1
during an active period of 6 to 8 days. The absorbance at 280 nm of 2 g of lignosulfonate liter
−1
increased during the first 3 days of incubation and decreased to 35% of the original value during the next 7 days. The capacity of 1 g of cells to degrade alkali-extracted straw lignin under optimized conditions was estimated to be as high as 1.0 g day
−1
. This degradation occurred with a simultaneous glucose consumption rate of 1.0 g day
−1
. When glucose or cellular energy resources were depleted, lignin degradation ceased. The ability of
P. chrysosporium
to degrade the various lignins in a similar manner and at very low biomass concentrations indicates that the enzymes responsible for lignin degradation are nonspecific.
Cyanide production by Pseudomonas fluorescens and Pseudomonas aeruginosa
Authors: Askeland R A , Morrison S M
Published: January 2020

Of 200 water isolates screened, five strains of Pseudomonas fluorescens and one strain of Pseudomonas aeruginosa were cyanogenic. Maximum cyanogenesis by two strains of P. fluorescens in a defined growth medium occurred at 25 to 30 degrees C over a pH range of 6.6 to 8.9. Cyanide production per cell was optimum at 300 mM phosphate. A linear relationship was observed between cyanogenesis and the log of iron concentration over a range of 3 to 300 microM. The maximum rate of cyanide production occurred during the transition from exponential to stationary growth phase. Radioactive tracer experiments with [1-14C]glycine and [2-14C]glycine demonstrated that the cyanide carbon originates from the number 2 carbon of glycine for both P. fluorescens and P. aeruginosa. Cyanide production was not observed in raw industrial wastewater or in sterile wastewater inoculated with pure cultures of cyanogenic Pseudomonas strains. Cyanide was produced when wastewater was amended by the addition of components of the defined growth medium.
Detection and activity of lactacin B, a bacteriocin produced by Lactobacillus acidophilus
Authors: Barefoot S F , Klaenhammer T R
Published: January 2020

A total of 52 strains of Lactobacillus acidophilus were examined for production of bacteriocins. A majority (63%) demonstrated inhibitory activity against all members of a four-species grouping of Lactobacillus leichmannii, Lactobacillus bulgaricus, Lactobacillus helveticus, and Lactobacillus lactis. Four L. acidophilus strains with this activity also inhibited Streptococcus faecalis and Lactobacillus fermentum, suggesting a second system of antagonism. Under conditions eliminating the effects of organic acids and hydrogen peroxide, no inhibition of other gram-positive or -negative genera was demonstrated by L. acidophilus. The agent produced by L. acidophilus N2 and responsible for inhibition of L. leichmannii, L. bulgaricus, L. helveticus, and L. lactis was investigated. Ultrafiltration studies indicated a molecular weight of approximately 100,000 for the crude inhibitor. The agent was sensitive to proteolytic enzymes and retained full activity after 60 min at 100 degrees C (pH 5). Activity against sensitive cells was bactericidal but not bacteriolytic. These characteristics identified the inhibitory agent as a bacteriocin, designated lactacin B. Examination of strains of L. acidophilus within the six homology groupings of Johnson et al. (Int. J. Syst. Bacteriol. 30:53-68, 1980) demonstrated that production of the bacteriocin lactacin B could not be used in classification of neotype L. acidophilus strains. However, the usefulness of employing sensitivity to lactacin B in classification of dairy lactobacilli is suggested.
Metabolism of Acetate, Methanol, and Methylated Amines in Intertidal Sediments of Lowes Cove, Maine
Authors: King Gary M. , Klug M. J. , Lovley D. R.
Published: January 2020

The fates and the rates of metabolism of acetate, trimethylamine, methylamine, and methanol were examined to determine the significance of these compounds as in situ methane precursors in surface sediments of an intertidal zone in Maine. Concentrations of these potential methane precursors were generally <3 μM, with the exception of sediments containing fragments of the seaweed
Ascophyllum nodosum
, in which acetate was 96 μM. [2-
14
C]acetate turnover in all samples was rapid (turnover time <2 h), with
14
CO
2
as the primary product. [
14
C]trimethylamine and methylamine turnover times were slower (>8 h) and were characterized by formation of both
14
CH
4
and
14
CO
2
. Ratios of
14
CH
4
/
14
CO
2
from [
14
C]trimethylamine and methylamine in uninhibited sediments indicated that a significant fraction of these substrates were catabolized via a non-methanogenic process. Data from inhibition experiments involving sodium molybdate and 2-bromoethanesulfonic acid supported this interpretation. [
14
C]methanol was oxidized relatively slowly compared with the other substrates and was catabolized mainly to
14
CO
2
. Results from experiments with molybdate and 2-bromoethanesulfonic acid suggested that methanol was oxidized primarily through sulfate reduction. In Lowes Cove sediments, trimethylamine accounted for 35.1 to 61.1% of total methane production.
Electron microscopic examination of wastewater biofilm formation and structural components
Authors: Eighmy T T , Maratea D , Bishop P L
Published: January 2020

This research documents in situ wastewater biofilm formation, structure, and physiochemical properties as revealed by scanning and transmission electron microscopy. Cationized ferritin was used to label anionic sites of the biofilm glycocalyx for viewing in thin section. Wastewater biofilm formation paralleled the processes involved in marine biofilm formation. Scanning electron microscopy revealed a dramatic increase in cell colonization and growth over a 144-h period. Constituents included a variety of actively dividing morphological types. Many of the colonizing bacteria were flagellated. Filaments were seen after primary colonization of the surface. Transmission electron microscopy revealed a dominant gram-negative cell wall structure in the biofilm constituents. At least three types of glycocalyces were observed. The predominant glycocalyx possessed interstices and was densely labeled with cationized ferritin. Two of the glycocalyces appeared to mediate biofilm adhesion to the substratum. The results suggest that the predominant glycocalyx of this thin wastewater biofilm serves, in part, to: (i) enclose the bacteria in a matrix and anchor the biofilm to the substratum and (ii) provide an extensive surface area with polyanionic properties.
Patulin biosynthesis: enzymatic and nonenzymatic transformations of the mycotoxin (E)-ascladiol
Authors: Sekiguchi J , Shimamoto T , Yamada Y , Gaucher G M
Published: January 2020

A mycotoxin, (E)-ascladiol, was established as a direct precursor of patulin in cell-free preparations of Penicillium urticae patulin-minus mutants J1 and S11, but not S15. Isomerization to a side product, (Z)-ascladiol, was nonenzymatically catalyzed by sulfhydryl compounds.
Adsorption of Bacteriophage eb7 on
Streptococcus cremoris
EB7
Authors: Keogh Barbara P. , Pettingill G.
Published: January 2020

When M17 broth was used as growth medium before preparation of cell walls, adsorption of phage eb7 on
Streptococcus cremoris
EB7 at pH 4.0 was stimulated. When preparation included treatment with trypsin, absorption of phage was 65%. Without trypsin treatment, absorption was 81%. Only 10 to 20% of the adsorption was irreversible. Treatment with pepsin or commercial rennet but not pure chymosin prevented adsorption on non-trypsin-treated cell walls.
d
-Galactosamine treatment of phage eb7 had an inactivating effect which was enhanced by
l
-rhamnose.
Simple Assay for Accurate Determination of [
35
S]sulfate Reduction Activity
Authors: Rosser H. Rick , Hamilton W. Allan
Published: January 2020

A method is described for the assay of [
35
S]sulfate reduction in which filter paper wicks are used to trap [
35
S]sulfide. The simplicity of the technique enables large numbers of samples to be conveniently processed. Enhanced sensitivity is achieved since all acid-volatile [
35
S]sulfides produced during the incubation period are counted. Recovery of radioactivity from added Na
2
35
S is excellent (mean, 100.1%; standard deviation, 1.81;
n
= 9) and is unaffected by sulfide concentrations of up to 400 μg per sample. Field trial results with anoxic sediment samples are presented.
Reuter Centrifugal Air Sampler: Measurement of Effective Airflow Rate and Collection Efficiency
Authors: Macher J. M. , First M. W.
Published: January 2020

Incorrect calculation of effective air sampling rate and disregard of differences in collection efficiency among samplers can lead to false conclusions about the usefulness of samplers for measuring concentrations of airborne microorganisms.
Predicting 2,4-Dichlorophenoxyacetic Acid Ester Transformation Rates in Periphyton-Dominated Ecosystems
Authors: Lewis David L. , Kollig Heinz P. , Hall Tom L.
Published: January 2020

Using batch cultures, we determined transformation rate coefficients for microbial transformation of 2,4-dichlorophenoxyacetic acid butoxyethyl ester (2,4-DBE) in periphyton-dominated ecosystems. Rates of 2,4-DBE loss were measured over short periods of time (usually less than 10 h), and first-order transformation rate coefficients (
k
1
) were determined under the specific conditions of low 2,4-DBE concentrations and no growth. Values for
k
1
were divided by total plate counts and by biomass measured as ash-free dry weight to give second-order rate coefficients (

k
b

and
k
AFDW
, respectively) for use in predictive models. Using periphyton attached to Teflon strips, we also determined second-order rate coefficients based on the ratio of colonized surface area to container volume (

k
A

). Mean second-order rate coefficients were used to predict 2,4-DBE transformation rates in microcosms having diverse chemical and biological environments. The observed transformation rates among the microcosms were most accurately predicted by using

k
A

.
Monensin-resistant bacteria in the rumens of calves on monensin-containing and unmedicated diets
Authors: Dawson K A , Boling J A
Published: January 2020

Total and monensin-resistant anaerobic bacterial populations and volatile fatty acid concentrations were examined in the rumens of steers fed monensin-containing (33 mg/kg) and unmedicated diets. Total anaerobic counts on a habitat-simulating medium ranged from 7.1 X 10(8) to 7.1 X 10(9) CFU/g of rumen ingesta and were not significantly different in animals fed the two diets. The mean percentage of the anaerobic population resistant to monensin (10 micrograms/ml) was significantly greater in animals receiving the monensin-supplemented diet for 33 days than in those receiving the unmedicated diet (63.6 and 32.8%, respectively). Treatment group differences in monensin resistance tended to develop later than characteristic differences in acetate/propionate ratios. Relative proportions of resistant organisms in monensin-fed animals remained significantly greater for at least 18 days after monensin was deleted from the ration, whereas acetate/propionate ratios increased to values comparable to those in the control within 10 days. These data suggest that monensin-resistant bacteria may be present in greater numbers in the rumens of animals fed monensin-supplemented diets. However, greater proportions of monensin-resistant organisms were not necessarily associated with altered fermentation patterns.
Production of Methyl Ketones from Secondary Alcohols by Cell Suspensions of C
2
to C
4
n
-Alkane-Grown Bacteria
Authors: Hou Ching T. , Patel Ramesh , Laskin Allen I. , Barnabe Nancy , Barist Irene
Published: January 2020

Nineteen new C
2
to C
4
n
-alkane-grown cultures were isolated from lake water from Warinanco Park, Linden, N.J., and from lake and soil samples from Bayway Refinery, Linden, N.J. Fifteen known liquid alkane-utilizing cultures were also found to be able to grow on C
2
to C
4
n
-alkanes. Cell suspensions of these C
2
to C
4
n
-alkane-grown bacteria oxidized 2-alcohols (2-propanol, 2-butanol, 2-pentanol, and 2-hexanol) to their corresponding methyl ketones. The product methyl ketones accumulated extracellularly. Cells grown on 1-propanol or 2-propanol oxidized both primary and secondary alcohols. In addition, the activity for production of methyl ketones from secondary alcohols was found in cells grown on either alkanes, alcohols, or alkylamines, indicating that the enzyme(s) responsible for this reaction is constitutive. The optimum conditions for in vivo methyl ketone formation from secondary alcohols were compared among selected strains:
Brevibacterium
sp. strain CRL56,
Nocardia paraffinica
ATCC 21198, and
Pseudomonas fluorescens
NRRL B-1244. The rates for the oxidation of secondary alcohols were linear for the first 3 h of incubation. Among secondary alcohols, 2-propanol and 2-butanol were oxidized at the highest rate. A pH around 8.0 to 9.0 was found to be the optimum for acetone or 2-butanone formation from 2-alcohols. The temperature optimum for the production of acetone or 2-butanone from 2-propanol or 2-butanol was rather high at 60°C, indicating that the enzyme involved in the reaction is relatively thermally stable. Metal-chelating agents inhibit the production of methyl ketones, suggesting the involvement of a metal(s) in the oxidation of secondary alcohols. Secondary alcohol dehydrogenase activity was found in the cell-free soluble fraction; this activity requires a cofactor, specifically NAD. Propane monooxygenase activity was also found in the cell-free soluble fraction. It is a nonspecific enzyme catalyzing both terminal and subterminal oxidation of
n
-alkanes.
Effects of nitric oxide and nitrogen dioxide on bacterial growth
Authors: Mancinelli R L , McKay C P
Published: January 2020

The effects of low concentrations of nitric oxide (NO) and nitrogen dioxide (NO2) on actively dividing cultures of Staphylococcus aureus, Micrococcus luteus, Micrococcus roseus, Serratia marcescens, Bacillus subtilis, Bacillus circulans, Bacillus megaterium, and Bacillus cereus were studied. Fresh cultures of each organism were incubated for 24 h at 25 degrees C on both nutrient agar and mineral salts glucose agar plates under atmospheres containing various low concentrations of NO in air (0 to 1.9 ppm [0 to 2.0 micrograms/g of air]), NO2 in air (0 to 5.5 ppm [0 to 8.8 micrograms/g of air]), or NO and NO2 in air. Bacteria grown under air only were used as controls. After incubation, the colonies that developed on the plates were counted. None of the bacteria tested was affected by NO or NO2 at the indicated concentrations while growing on nutrient agar. Serratia marcescens, B. circulans, B. subtilis, B. megaterium, and B. cereus grown on mineral salts glucose agar were not significantly affected by NO or NO2. Low concentrations (0 to 1.9 ppm) of NO were bacteriostatic to log-phase cultures of M. roseus, M. luteus, and Staphylococcus aureus grown on mineral salts glucose agar. Bacteriostatic activity over a 24-h interval was maximal at an initial NO concentration of 1 ppm. Appreciable amounts of NO2 were produced in 24 h at initial NO concentrations greater than 1 ppm. These results suggest that NO2 may reduce the bacteriostatic activity of NO. Low concentrations (0 to 5.5 ppm) of NO2 in air did not affect any of the bacteria tested. At these low concentrations, NO affected bacterial growth, although NO2, NO2-, and NO3- did not. In addition, it was determined that the bacteriostatic activity observed in this study was not due to an increase in the acidity of the medium.
Paper replication method for isolation of radiation-sensitive mutants
Authors: Tan S T , Maxcy R B , Thompson T L
Published: January 2020

A filter paper replication system particularly useful for isolation of radiation-sensitive mutants of pigmented bacteria was devised. The fidelity of replication was high. Adhesion between a paper disk and a properly dried master plate provided adequate contact pressure. The replicas arising from this technique constitute a convenient apparatus for general application in isolation of clones sensitive to a discriminating treatment.
Incidence and level of Vibrio parahaemolyticus associated with freshwater plankton
Authors: Sarkar B L , Nair G B , Sircar B K , Pal S C
Published: January 2020

We isolated Vibrio parahaemolyticus from plankton samples collected from different freshwater areas in the vicinity of Calcutta, India. Levels of this organism in association with freshwater plankton were low (less than 90 organisms per g). All of the 16 strains of V. parahaemolyticus isolated in this study were Kanagawa negative, and all except 1 were untypable. The occurrence of V. parahaemolyticus in association with freshwater plankton suggests that adsorption onto plankton may aid the survival of this moderately halophilic organism in freshwater milieus.
Production of 3-Hydroxypropionaldehyde from Glycerol
Authors: Slininger Patricia J. , Bothast Rodney J. , Smiley Karl L.
Published: January 2020

3-Hydroxypropionaldehyde is a precursor to acrolein, which can be used as an intermediate for making acrylic acid and a variety of other useful industrial chemicals. Conversion of glycerol, a renewable resource, to 3-hydroxypropionaldehyde was attempted via action of glycerol dehydrase isolated from
Lactobacillus
sp. strain NRRL B-1720. This method, however, was unsatisfactory because enzyme activity was lost within 60 to 90 min after the reaction initiation. Fermentation of glycerol by whole cells of
Klebsiella pneumoniae
NRRL B-199 in the presence of optimal semicarbazide hydrochloride proved more effective. Using this technique, glycerol solutions of 30 g/liter yielded 3-hydroxypropionaldehyde solutions of 13.1 g/liter. Thus, a conversion efficiency equal to 55% of the theoretical maximum was realized.
Effects of Fermentation and Its Control on the Sensory Characteristics of Conservolea Variety Green Olives
Authors: Balatsouras G. , Tsibri A. , Dalles T. , Doutsias G.
Published: January 2020

The various factors assumed to retard or even prevent the lactic acid fermentation of Conservolea variety green olives have been investigated. Of these, the sugar supplement along with the appropriate lactic starter culture supported a complete lactic acid fermentation. Acidification, particularly of starting brine, was shown to have little or no effect, whereas heat shock treatment improved the olive fermentability slightly without modifying the course of fermentation. These findings indicate that Conservolea olives do not contain phenolic compounds in concentrations inhibitory to lactic acid bacteria.
Surface thermodynamics of bacterial adhesion
Authors: Absolom D R , Lamberti F V , Policova Z , Zingg W , van Oss C J , Neumann A W
Published: January 2020

The adhesion of five strains of bacteria, i.e., Staphylococcus aureus (strain 049), Staphylococcus epidermidis (strain 047), Escherichia coli (strains 055 and 2627), and Listeria monocytogenes, to various polymeric surfaces was studied. The design of the experimental protocol was dictated by thermodynamic considerations. From the thermodynamic model for the adhesion of small particles from a suspension onto a solid substratum, it follows that the extent of adhesion is determined by the surface properties of all three phases involved, i.e., the surface tensions of the adhering particles, of the substrate, and of the suspending liquid medium. In essence, adhesion is more extensive to hydrophilic substrata (i.e., substrata of relatively high surface tension) than to hydrophobic substrata, when the surface tension of the bacteria is larger than that of the suspending medium. When the surface tension of the suspending liquid is larger than that of the bacteria, the opposite pattern of behavior prevails. Suspensions of bacteria at a concentration of 10(8) microorganisms per ml were brought into contact with several polymeric surfaces (Teflon, polyethylene, polystyrene, and acetal and sulfonated polystyrene) for 30 min at 20 degrees C. After rinsing, the number of bacteria adhering per unit surface area was determined by image analysis. The surface tension of the suspending medium. Hanks balanced salt solution, was modified through the addition of various amounts of dimethyl sulfoxide. It was found that the number of bacteria adhering per unit surface area correlates well with the thermodynamic predictions and that these data may be used to determine the surface tension of the different bacterial species. The surface tensions of the bacteria obtained in this fashion are in excellent agreement with those obtained by other methods.
Isolation of a
Pseudomonas
sp. Which Utilizes the Phosphonate Herbicide Glyphosate
Authors: Moore J. Kent , Braymer Hugh D. , Larson Alworth D.
Published: January 2020

A strain of bacteria has been isolated which rapidly and efficiently utilizes the herbicide glyphosate (
N
-phosphonomethylglycine) as its sole phosphorus source in a synthetic medium. The strain (PG2982) was isolated by subculturing
Pseudomonas aeruginosa
ATCC 9027 in a synthetic broth medium containing glyphosate as the sole phosphorus source. Strain PG2982 differs from the culture of
P. aeruginosa
in that it is nonflagellated, does not produce pyocyanin, and has an absolute requirement for thiamine. Strain PG2982 has been tentatively identified as a
Pseudomonas
sp. strain by its biochemical activities and moles percent guanine plus cytosine. Measurements of glyphosate with an amino acid analyzer show that glyphosate rapidly disappears from the medium during exponential growth of strain PG2982. In batch culture at 30�C, this isolate completely utilized 1.0 mM glyphosate in 96 h and yielded a cell density equal to that obtained with 1.0 mM phosphate as the phosphorus source. However, a longer lag phase and greater generation time were noted in the glyphosate-containing medium. Strain PG2982 can efficiently utilize glyphosate as an alternate phosphorus source.
Effect of H
2
-CO
2
on Methanogenesis from Acetate or Methanol in
Methanosarcina
spp
Authors: Ferguson Thomas J. , Mah Robert A.
Published: January 2020

Growth of
Methanosarcina
sp. strain 227 and
Methanosarcina mazei
on H
2
-CO
2
and mixtures of H
2
-CO
2
and acetate or methanol was examined. The growth yield of strain 227 on H
2
-CO
2
in complex medium was 8.4 mg/mmol of methane produced. Growth in defined medium was characteristically slower, and cell yields were proportionately lower. Labeling studies confirmed that CO
2
was rapidly reduced to CH
4
in the presence of H
2
, and little acetate was used for methanogenesis until H
2
was exhausted. This resulted in a biphasic pattern of growth similar to that reported for strain 227 grown on methanol-acetate mixtures. Biphasic growth was not observed in cultures on mixtures of H
2
-CO
2
and methanol, and less methanol oxidation occurred in the presence of H
2
. In
M. mazei
the aceticlastic reaction was also inhibited by the added H
2
, but since the cultures did not immediately metabolize H
2
, the duration of the inhibition was much longer.
Aspergillus fumigatus and other thermotolerant fungi generated by hospital building demolition
Authors: Streifel A J , Lauer J L , Vesley D , Juni B , Rhame F S
Published: January 2020

On 13 September 1981, a 51-year-old seven-story building within our hospital complex was demolished by explosives. The concern that this event might release large numbers of thermotolerant fungi (TF), potentially hazardous to immunosuppressed patients, led us to seal hospital windows and doors. The air-handling systems were also manipulated. Concentrations of airborne TF, especially Aspergillus fumigatus, were determined before and after demolition, using Andersen and Cassella air samplers with inhibitory mold agar plates. Two outdoor and two hospital ward locations were sampled. The plates were incubated at 37 degrees C; the CFU per cubic meter were counted at 72 h. The outdoor concentration of TF increased at one site by an average of 1.8 log10 (10(2) to 10(5] over the predemolition level. A. fumigatus increased 3.3 log10 (10(0) to 10(4] at the other outdoor site. The indoor TF concentrations increased about 1 log10 (10(1) to 10(2] after demolition. Counts on the hospital wards were not remarkable when compared with previous surveillance air sampling. Protective measures apparently minimized the infiltration of TF during explosive demolition.
Microbial growth associated with granular activated carbon in a pilot water treatment facility
Authors: Wilcox D P , Chang E , Dickson K L , Johansson K R
Published: January 2020

The microbial dynamics associated with granular activated carbon (GAC) in a pilot water treatment plant were investigated over a period of 16 months. Microbial populations were monitored in the influent and effluent waters and on the GAC particles by means of total plate counts and ATP assays. Microbial populations between the influent and effluent waters of the GAC columns generally increased, indicating microbial growth. The dominant genera of microorganisms isolated from interstitial waters and GAC particles were Achromobacter, Acinetobacter, Aeromonas, Alcaligenes, Bacillus, Chromobacterium, Corynebacterium, Micrococcus, Microcyclus, Paracoccus, and Pseudomonas. Coliform bacteria were found in small numbers in the effluents from some of the GAC columns in the later months of the study. Oxidation of influent waters with ozone and maintenance of aerobic conditions on the GAC columns failed to appreciably enhance the microbial growth on GAC.
Comparison of media for isolation of poultry intestinal bacteria
Authors: Kelley R W
Published: January 2020

The effects of medium composition, incubation temperature, and length of incubation were determined for recovery of the predominant intestinal bacteria from turkey poults. Incubation of recovery media at 41 degrees C resulted in significantly higher counts than at 37 degrees C. In 2- and 3-week-old turkey poults. RGCAP-30, RGCAP-10, and RGCA-30 gave the highest recoveries of cecal bacteria. M98-5 was less effective and brain heart infusion agar was definitely inadequate. However, there was no significant difference between RGCAP-30 and brain heart infusion agar for recovery of duodenal bacteria. In older birds (6 weeks of age), M98-5 was equal or superior to the RGCA-based media. The choice of a primary isolation medium is thus dependent on the site to be sampled and the age of the bird.
Purification and Characterization of α-Amylase from
Bacillus licheniformis
CUMC305
Authors: Krishnan T. , Chandra A. K.
Published: January 2020

α-Amylase produced by
Bacillus licheniformis
CUMC305 was purified 212-fold with a 42% yield through a series of four steps. The purified enzyme was homogeneous as shown by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and discontinuous gel electrophoresis. The purified enzyme showed maximal activity at 90�C and pH 9.0, and 91% of this activity remained at 100�C. The enzyme retained 91, 79, and 71% maximal activity after 3 h of treatment at 60�C, 3 h at 70�C, and 90 min at 80�C, respectively, in the absence of substrate. On the contrary, in the presence of substrate (soluble starch), the α-amylase enzyme was fully stable after a 4-h incubation at 100�C. The enzyme showed 100% stability in the pH range 7 to 9; 95% stability at pH 10; and 84, 74, 68, and 50% stability at pH values of 6, 5, 4, and 3, respectively, after 18 h of treatment. The activation energy for this enzyme was calculated as 5.1 � 10
5
J/mol. The molecular weight was estimated to be 28,000 by sodium dodecyl sulfate-gel electrophoresis. The relative rates of hydrolysis of soluble starch, amylose, amylopectin, and glycogen were 1.27, 1.8, 1.94, and 2.28 mg/ml, respectively.
V
max
values for hydrolysis of these substrates were calculated as 0.738, 1.08, 0.8, and 0.5 mg of maltose/ml per min, respectively. Of the cations, Na
+
, Ca
2+
, and Mg
2+
, showed stimulatory effect, whereas Hg
2+
, Cu
2+
, Ni
2+
, Zn
2+
, Ag
+
, Fe
2+
, Co
2+
, Cd
2+
, Al
3+
, and Mn
2+
were inhibitory. Of the anions, azide, F
−
, SO
3
2−
, SO
4
3−
, S
2
O
3
2−
, MoO
4
2−
, and Wo
4
2−
showed an excitant effect.
p
-Chloromercuribenzoic acid and sodium iodoacetate were inhibitory, whereas cysteine, reduced glutathione, thiourea, β-mercaptoethanol, and sodium glycerophosphate afforded protection to enzyme activity. α-Amylase was fairly resistant to EDTA treatment at 30�C, but heating at 90�C in presence of EDTA resulted in the complete loss of enzyme activity, which could be recovered partially by the addition of Cu
2+
and Fe
2+
but not by the addition of Ca
2+
or any other divalent ions.
Isolation and Characterization of
Methanomicrobium paynteri
sp. nov., a Mesophilic Methanogen Isolated from Marine Sediments
Authors: Rivard Christopher J. , Henson J. Michael , Thomas Michael V. , Smith Paul H.
Published: January 2020

A new mesophilic methanogenic bacterial species isolated from marine sediments collected in the Cayman Islands is described. Cells are small rods occuring singly without filaments, are not motile, and do not possess flagella. Colonies are semitransparent and off-white in color. After 2 weeks of incubation at 37°C colonies are 1 to 2 mm in size, circular, and have entire edges. Only hydrogen-carbon dioxide is a substrate for growth and methane formation. Cells can tolerate a variety of organic secondary buffers (bicarbonate-CO
2
being the primary buffer). Cells do not require yeast extract or Trypticase, but do require acetate, for growth. The optimum growth temperature is 40°C. The optimum sodium concentration is 0.15 M. The optimum pH for growth is 7.0. The minimum generation time is 4.8 h. The DNA base composition is 44.9 mol% guanine plus cytosine. The name
Methanomicrobium paynteri
is proposed in honor of M. J. B. Paynter. The type strain is G-2000 (=ATCC 33997, =DSM 2545).

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Effect of pyridazinone herbicides on growth and aflatoxin release by Aspergillus flavus and Aspergillus parasiticus
Authors: Bean G A , Southall A
Published: January 2020

The influence of pyridazinone herbicides on aflatoxin production by Aspergillus flavus and A. parasiticus was studied in liquid media. Mycelia production was not affected by 20, 40, or 60 micrograms of herbicide per ml; however, aflatoxin production by A. parasiticus was higher in media with herbicide, whereas A. flavus produced lower aflatoxin levels.
Prevention of Staphylococcus aureus lysis
Authors: Bhaduri S
Published: January 2020

Staphylococcus aureus S-6 cells grown in chemically defined media often lysed after exponential growth. Lysis could be prevented by the addition of alanine or proline before the culture reached stationary phase.
Isolation, Purification, and Some Properties of
Penicillium chrysogenum
Tannase
Authors: Rajakumar G. Suseela , Nandy S. C.
Published: January 2020

Tannase isolated from
Penicillium chrysogenum
was purified 24-fold with 18.5% recovery after ammonium sulfate precipitation, DEAE-cellulose column chromatography, and Sephadex G-200 gel filtration. Optimum enzyme activity was recorded at pH 5.0 to 6.0 and at 30 to 40�C. The enzyme was stable up to 30�C and within the pH range of 4.0 to 6.5. The

K
m

value was found to be 0.48 � 10
−4
M when tannic acid was used as the substrate. Metal salts at 20 mM inhibited the enzyme to different levels.
Wide-Host-Range Plasmids Function in the Genus
Thiobacillus
Authors: Davidson M. S. , Summers Anne O.
Published: January 2020

Plasmids S-a, RP4, R388, and several RP4 derivatives (pMD101, pDT387, and pDT566) were transmissible by conjugation to
Thiobacillus novellus
from
Escherichia coli
. Genetic markers were expressed in
T. novellus
, with the exception of chloramphenicol resistance and ampicillin resistance. Plasmids were not transmissible by conjugation from
E. coli
donors to
Thiobacillus intermedius, T. perometabolis, T. neapolitanus
, or
T. acidophilus
recipients, although they could be mated into these strains from
T. novellus
. All
Thiobacillus
species tested could transfer plasmids back to
E. coli
, with the exception of
T. acidophilus
. The donor-specific bacteriophages PRR1 and PRD1 were incapable of initiating the lytic cycle in RP4-bearing strains of
T. novellus
. The cosmid cloning vehicle pVK100 could be mobilized from
E. coli
to
T. novellus
with the aid of the “helper” plasmid pRK2013. pVK100 is stable in
T. novellus
, but pRK2013 is not maintained in this species. pRK2013 was also used to mobilize another cloning vector, R300B, to
T. novellus
. A previously unreported cryptic plasmid of approximately 24 megadaltons was observed in
T. intermedius
. No native plasmids were demonstrated in the other
Thiobacillus
species except in
T. acidophilus
, which contained cryptic plasmids ranging in size from 7.6 to 56 megadaltons (molecular mass).
Predicting coliform concentrations in upland impoundments: design and calibration of a multivariate model
Authors: Kay D , McDonald A
Published: January 2020

This paper reports on the calibration and use of a multiple regression model designed to predict concentrations of Escherichia coli and total coliforms in two upland British impoundments. The multivariate approach has improved predictive capability over previous univariate linear models because it includes predictor variables for the timing and magnitude of hydrological input to the reservoirs and physiochemical parameters of water quality. The significance of these results for catchment management research is considered.
Characterization of staphylococci
Authors: Hoover D G , Tatini S R , Maltais J B
Published: January 2020

A total of 158 Staphylococcus strains from various sources were characterized by biochemical, physiological, and morphological tests. Numerical taxonomy was applied by using these features. Taxonomic analysis was done with programs run under the MVS-TSO system of the IBM 370 complex and PDP-10 system of the National Institutes of Health. DNA-DNA hybridization with nitrocellulose filters was done to compare selected atypical cultures with American Type Culture Collection reference strains. We found that the use of the nomenclature of Bergey's Manual (8th edition) to identify these strains by species was not adequate. DNA homology values supported the formation of Staphylococcus hyicus subsp. hyicus separate from Staphylococcus aureus, Staphylococcus epidermidis, and Staphylococcus saprophyticus. The three tests that best separated these strains into four species were (i) tube coagulase (6-h or 24-h porcine plasma or 24-h Difco rabbit plasma), (ii) production of acetoin or acid aerobically from ribose, maltose, or trehalose, and (iii) growth in the presence of novobiocin. Four strains of S. hyicus subsp. hyicus (VII76, VII113, VII131, and VA519) gave typical enterotoxigenic responses in monkey-feeding tests but were negative for enterotoxins A through E, suggesting the presence of one or more new enterotoxins. Two coagulase-negative, heat-stable DNase-positive strains (D143 and ARM) could not be classified by either DNA-DNA hybridization or numerical taxonomy, and D143 was enterotoxigenic as measured by the monkey-feeding bioassay. DNA homology showed that strain FRI-698M was more closely related to S. epidermidis than to S. aureus, yet it produced enterotoxin D. These data suggest the occurrence of coagulase-negative enterotoxigenic strains that are not S. aureus; nonetheless, a positive tube coagulase test and heat-stable DNase test should together be useful for routine screening of most potentially enterotoxigenic staphylococci in foods.
Mutagenesis of Micromonospora rosaria by using protoplasts and mycelial fragments
Authors: Kim K S , Cho N Y , Pai H S , Ryu D D
Published: January 2020

Both mycelial fragments and protoplasts were successfully employed for mutagenesis of Micromonospora rosaria NRRL 3718, and the results were compared. The optimal conditions and effective procedures for mutagenesis of M. rosaria by a chemical mutagen, N-methyl-N'-nitro-N-nitrosoguanidine, have been determined. Mutation was efficiently induced when mycelial fragments were treated with N-methyl-N'-nitro-N-nitrosoguanidine at a concentration of 0.3 to 0.5 mg/ml in the reaction buffer of pH 7.0. Optimal treatment time was 20 to 40 min. Ampicillin treatment was very effective for enrichment of auxotrophs. Protoplasts showed much higher sensitivity to the lethal effect of N-methyl-N'-nitro-N-nitrosoguanidine. Although protoplasts have some advantage of single cell characteristics, the frequency of auxotrophs obtained was somewhat lower. Up to 4% of the colonies were shown to be auxotrophs under the well-defined conditions. This mutagenesis method with protoplasts or fragmented mycelia (or both) should be applicable to other actinomycetes that have limited or no sporulation.
N
2
Fixation by
Azospirillum brasilense
and Its Incorporation into Host
Setaria italica
Authors: Okon Yaacov , Heytler P. G. , Hardy R. W. F.
Published: January 2020

Growth and nitrogen fixation were followed during the life cycle of
Setaria italica
(foxtail millet) inoculated with
Azospirillum brasilense
in controlled-environment growth chambers. The plants were fertilized at seeding with a limiting amount of combined nitrogen and maintained with an N-free mineral solution. During maturation of the plants, substantial nitrogenase activity, measured by acetylene reduction, developed in the rhizosphere, with total fixation estimated to be equivalent to 20% of the N in the inoculated plants. The peak of this activity coincided with depletion of soluble nitrogen from the system, which in turn was reflected by a sharp decrease in the nitrate reductase activity of the leaves.
A. brasilense
was found in association with the root populations at 8 × 10
7
cells per gram of dry weight. An increase in shoot growth occurred at this time, but no significant increase in total plant nitrogen could be demonstrated.
15
N
2
enrichment experiments confirmed that fixation was occurring, but only about 5% of the nitrogen fixed by
A. brasilense
was incorporated into the plants within 3 weeks. There was thus no evidence of direct bacterium-to-plant transport of fixed nitrogen, but rather a slow transfer suggesting the gradual death of bacteria and subsequent mineralization of their nitrogen, at least under growth-room conditions.
Cyclopiazonic acid production by Aspergillus flavus and its effects on broiler chickens
Authors: Dorner J W , Cole R J , Lomax L G , Gosser H S , Diener U L
Published: January 2020

Cyclopiazonic acid (CPA) was purified from cultures of Aspergillus flavus, and ca. 14 g of the toxin was collected for use in feeding studies. Chicken rations were artificially contaminated with purified CPA at concentrations of 10, 50, and 100 ppm (microgram/g) and fed ad libitum to eight groups of chickens for 7 weeks. Chickens receiving feed with 100 ppm of CPA had high mortality, decreased weight gain, and poor feed conversion when compared with birds receiving other doses. Postmortem examination showed that chickens fed the two greatest doses of CPA had proventricular lesions characterized by mucosal erosion and hyperemia (100 ppm) and by thick mucosa and dilated proventricular lumens (50 ppm). Birds given 100 ppm of CPA in feed also had numerous yellow foci in their livers and spleens. Microscopic examination of tissues of birds that received 100 ppm of CPA revealed ulcerative proventriculitis, mucosal necrosis in the gizzard, and hepatic and splenic necrosis and inflammation. Birds given 50 ppm of CPA had hyperplasia of the proventricular mucosal epithelium. Birds given 10 ppm of CPA and control birds had no significant treatment-related lesions.
Kinetics of two subgroups of propionate-using organisms in anaerobic digestion
Authors: Heyes R H , Hall R J
Published: January 2020

A novel method for measuring the kinetics of a subgroup of organisms growing in mixed culture was used to measure the kinetics of propionate-using organisms in a mixed-population anaerobic digester. It was shown that there are at least two subgroups of propionate-using organisms with distinctly different growth kinetics. Both subgroups could grow without reducing sulfate. The slower-growing subgroup had a Ks of 11 mg/liter and a mumax of 0.0054 h-1 which is similar to the mumax reported for Syntrophobacter wolinii. The faster-growing group had a mumax of 0.050 h-1 and a Ks of 330 mg/liter. The slower-growing group was inhibited by a pH shock from 7.0 to 6.0, whereas the faster-growing group was less sensitive to the pH shock.
Effect of specific amino acids on growth and aflatoxin production by Aspergillus parasiticus and Aspergillus flavus in defined media
Authors: Payne G A , Hagler W M
Published: January 2020

Four amino acids were used as sole nitrogen sources or as supplements to ammonium sulfate, and casein and ammonium sulfate were used as sole nitrogen sources to examine their effects on aflatoxin production by Aspergillus parasiticus NRRL 2999 and Aspergillus flavus 3357 grown on synthetic liquid media. In general, when proline, asparagine, casein, and ammonium sulfate were used as sole nitrogen sources, they supported more growth and toxin production than tryptophan or methionine. However, proline stimulated more toxin production per gram of mycelium in stationary cultures than the other nitrogen sources, including the amino acid asparagine, which is generally recognized as supporting good aflatoxin production. The exact responses to individual nitrogen sources were influenced by the species of fungus and whether cultures were stationary or shaken. In shake cultures, but not in stationary cultures, increased growth was generally associated with increased toxin production.
Novel method for selective isolation of actinomycetes
Authors: Hirsch C F , Christensen D L
Published: January 2020

A new technique for the selective isolation of actinomycetes from natural mixed microbial populations is described. A nutrient agar medium was overlaid with a 0.22- to 0.45-microns-pore cellulose ester membrane filter, and the surface of the filter was inoculated. During incubation, the branched mycelia of the actinomycetes penetrated the filter pores to the underlying agar medium, whereas growth of nonactinomycete bacteria was restricted to the filter surface. The membrane filter was removed, and the agar medium was reincubated to allow the development of the isolated actinomycete colonies. This procedure selects actinomycetes on the basis of their characteristic mycelial mode of growth, offers a general method for their selective isolation, and does not rely on the use of special nutrient media or of antibacterial antibiotics.
Simple and rapid method for disruption of bacteria for protein studies
Authors: Bhaduri S , Demchick P H
Published: January 2020

A simple and rapid method was developed for the extraction of proteins from both pathogenic and nonpathogenic bacteria. The method involves the treatment of cells with acetone followed by sodium dodecyl sulfate extraction of cellular proteins. Polyacrylamide gel electrophoresis revealed that the protein composition of extracts made by this method was comparable to that of extracts made by established methods, namely, sonication and agitation with beads. This technique has been successfully applied to the extraction of proteins from a wide variety of bacteria, including pathogens.
Confirmation of Occurrence of Hydroxamate Siderophores in Soil by a Novel
Escherichia coli
Bioassay
Authors: Powell Paul E. , Szaniszlo Paul J. , Reid C. P. Patrick
Published: January 2020

The occurrence of ferrichrome-type hydroxamate siderophores in soil was confirmed. In the presence of the iron-scavenging chelator ethylenediamine[di(
o
-hydroxyphenylacetic)acid], soil extract stimulated the growth of an
Escherichia coli
strain possessing the ferrichrome transport protein (TonA) but did not stimulate growth of a strain lacking this protein (TonA
−
). The siderophore concentration in a 1:1 (soil-water) extract was estimated to be approximately 78 nM. Specificity of the assay was supported by the absence of significant differential strain responses to ferric citrate, ferric 2,3-dihydroxybenzoate, enterochelin, ferrioxamine B, coprogen, and triacetylfusigen.
Susceptibility of Legionella pneumophila to chlorine in tap water
Authors: Kuchta J M , States S J , McNamara A M , Wadowsky R M , Yee R B
Published: January 2020

A study was conducted to compare the susceptibility of legionellae and coliforms to disinfection by chlorine. The chlorine residuals used were similar to concentrations that might be found in the distribution systems of large public potable water supplies. The effects of various chlorine concentrations, temperatures, and pH levels were considered. A number of different Legionella strains, both environmental and clinical, were tested. The results indicate that legionellae are much more resistant to chlorine than are coliform bacteria. At 21 degrees C, pH 7.6, and 0.1 mg of free chlorine residual per liter, a 99% kill of L. pneumophila was achieved within 40 min, compared with less than 1 min for Escherichia coli. The observed resistance is enhanced as conditions for disinfection become less optimal. The required contact time for the removal of L. pneumophilia was twice as long at 4 degrees C than it was at 21 degrees C. These data suggest that legionellae can survive low levels of chlorine for relatively long periods of time.
DNA-DNA hybridization assay for detection of Salmonella spp. in foods
Authors: Fitts R , Diamond M , Hamilton C , Neri M
Published: January 2020

We have developed a DNA-DNA hybridization test for the presence of Salmonella spp. in foods. This test requires an initial pre-enrichment of food samples in nutrient broth but does not require selective enrichment. Samples of food cultures are collected on membrane filters and assayed by molecular hybridization to labeled probes. The probes consist of DNA sequences which are unique to the genus Salmonella and are widely distributed in the genus. A diverse panel of foods was assayed successfully by this methodology.
Growth of a Strictly Anaerobic Bacterium on Furfural (2-Furaldehyde)
Authors: Brune Gerhard , Schoberth Siegfried M. , Sahm Hermann
Published: January 2020

A strictly anaerobic bacterium was isolated from a continuous fermentor culture which converted the organic constituents of sulfite evaporator condensate to methane and carbon dioxide. Furfural is one of the major components of this condensate. This furfural isolate could degrade furfural as the sole source of carbon and energy in a defined mineral-vitamin-sulfate medium. Acetic acid was the major fermentation product. This organism could also use ethanol, lactate, pyruvate, or fumarate and contained cytochrome
c
3
and desulfoviridin. Except for furfural degradation, the characteristics of the furfural isolate were remarkably similar to those of the sulfate reducer
Desulfovibrio gigas.
The furfural isolate has been tentatively identified as
Desulfovibrio
sp. strain F-1.