bluuebunny/crossref_metadata_2025 huggingface dataset:
Cloning and expression of an alpha-acetolactate decarboxylase gene from Streptococcus lactis subsp. diacetylactis in Escherichia coli
Authors: Goelling D , Stahl U
Published: January 2020

The Streptococcus lactis gene coding for alpha-acetolactate decarboxylase (ADC) was cloned in Escherichia coli. Subsequent subcloning in E. coli showed that the ADC gene was located within a 1.3-kilobase DNA fragment. The ADC gene was controlled by its own promoter. Gas chromatography showed that S. lactis and the transformed E. coli strains produced the two optical isomers of acetoin in different ratios.
Polysaccharide Production by Propionibacteria during Lactose Fermentation
Authors: Crow Vaughan L.
Published: January 2020

The fermentation products from 10 strains of propionibacteria accounted for only 72% (average value) of the lactose carbon utilized. The balance of the carbon was accounted for by the production of a polysaccharide containing methylpentose (the major component), glucose, and galactose. The presence of methylpentose explained the low ratios of propionate to acetate (<2:1).
Some Changes in Gut Bacterial Flora of Field-Grown
Peridroma saucia
(Lepidoptera: Noctuidae) When Brought into the Laboratory
Authors: Lighthart Bruce
Published: January 2020

Removal of
Peridroma saucia
from the field to the laboratory caused little change in the quantity of facultative and aerobic bacteria in the gut but produced significant qualitative and quantitative changes in distinguishable groups of the family
Enterobacteriaceae
in the gut.
Nodulation and Nitrogen Fixation Efficacy of
Rhizobium fredii
with
Phaseolus vulgaris
Genotypes
Authors: Sadowsky Michael J. , Cregan Perry B. , Keyser Harold H.
Published: January 2020

Phaseolus
plant introduction (PI) genotypes (consisting of 684
P. vulgaris
, 26
P. acutifolius
, 39
P. lunatus
, and 5
P. coccineus
accessions) were evaluated for their ability to form effective symbioses with strains of six slow-growing (
Bradyrhizobium
) and four fast-growing (
Rhizobium fredii
) soybean rhizobia. Of the 684
P. vulgaris
genotypes examined, three PIs were found to form effective nitrogen-fixing symbioses with the
R. fredii
strains. While none of the
Bradyrhizobium
strains nodulated any of the genotypes tested, some produced large numbers of undifferentiated root proliferations (hypertrophies). A symbiotic plasmid-cured
R. fredii
strain failed to nodulate the
P. vulgaris
PIs and cultivars, suggesting that
P. vulgaris
host range genes are Sym plasmid borne in the fast-growing soybean rhizobia.
Esterase activities in Butyrivibrio fibrisolvens strains
Authors: Hespell R B , O'Bryan-Shah P J
Published: January 2020

Thirty strains of Butyrivibrio fibrisolvens isolated in diverse geographical locations were examined for esterase activity by using naphthyl esters of acetate, butyrate, caprylate, laurate, and palmitate. All strains possessed some esterase activity, and high levels of activity were observed with strains 49, H17c, S2, AcTF2, and LM8/1B. Esterase activity also was detected in other ruminal bacteria (Bacteroides ruminicola, Selenomonas ruminantium, Ruminobacter amylophilus, and Streptococcus bovis). For all B. fibrisolvens strains tested, naphthyl fatty acid esterase activity paralleled culture growth and was predominantly cell associated. With strains 49, CF4c, and S2, the activity was retained by protoplasts made from whole cells. Esterase activity was detected with all strains when grown on glucose, and some strains showed higher activity levels when grown on other substrates (larchwood xylan or citrus pectin). When nitrophenyl esters of fatty acids were used to measure esterase activity, generally four- to sevenfold-higher activity levels were detected, and with a number of strains substantial levels were found in the culture fluid. Cultures of these strains (H17c, NOR37, D1, and D30g) contained xylanase and acetyl xylan esterase activities, neither of which was associated to any great extent with the cells. Acetyl xylan esterase has not been previously detected in ruminal bacteria and may be important to overall digestion of forage by these organisms.
Concomitant Conjugal Transfer of Reduced-Bacteriophage-Sensitivity Mechanisms with Lactose- and Sucrose-Fermenting Ability in Lactic Streptococci
Authors: Murphy Maeve C. , Steele James L. , Daly Charles , McKay Larry L.
Published: January 2020

Ten previously reported lactose-positive (Lac
+
) transconjugants from
Streptococcus lactis, S. cremoris
, and
S. lactis
subsp.
diacetylactis
and one sucrose-positive (Suc
+
) transconjugant from
S. lactis
were examined for their sensitivity to prolate- and small isometric-headed bacteriophages. Four of the Lac
+
transconjugants showed a 10- to 100-fold reduction in the efficiency of plating (EOP) as well as a reduced plaque size for the prolate phage c2 and were insensitive to the small isometric phage 712. A fifth Lac
+
transconjugant demonstrated a similar reduced sensitivity to phage c2; however, this transconjugant was able to plaque phage 712, but with a reduced plaque size and EOP. The other five Lac
+
transconjugants were sensitive to both c2 and 712 phages. The Suc
+
transconjugant plaqued phage 712 with a reduced plaque size and EOP, but no reduction in plaque size or EOP was observed for phage c2. The Lac
+
and reduced bacteriophage sensitivity (Rbs
+
) phenotypes were correlated with specific plasmids in the Lac
+
transconjugants. As four of the Lac
+
transconjugants exhibited a phenotypically indistinguishable Rbs
+
, one (AB001) was selected for further study. The Rbs
+
in AB001 for both small isometric- and prolate-headed phages was not related to adsorption, and the reduced EOP for phage c2 was not related to the presence of a restriction and modification system. The latent period for phage c2 was unchanged, but the burst size was reduced 80%. The presence of the plasmid coding for Rbs
+
retarded the lysis of a mitomycin C-induced prophage-containing strain. The Rbs
+
mechanism appears to be abortive phage infection. This study supports previous observations that Rbs
+
and conjugal transfer ability are physically linked among some group N streptococci. The results presented have implications in the identification of plasmids coding for Rbs
+
and may also aid in explaining the dissemination of Rbs
+
genes among lactic streptococci.
Stress- and Growth Phase-Associated Proteins of
Clostridium acetobutylicum
Authors: Terracciano Joseph S. , Rapaport Eliezer , Kashket Eva R.
Published: January 2020

The response of
Clostridium acetobutylicum
ATCC 4259 to the stresses produced by a temperature upshift from 28°C to 45°C and by exposure of the organisms to 0.1%
n
-butanol or to air was examined by analysis of pulse-labeled proteins. The stress response was the induction of the synthesis of a number of proteins, some of which were elicited by the three forms of stress. Eleven heat shock proteins were identified by two-dimensional electrophoresis, as were two proteins whose synthesis was heat sensitive. In the absence of applied stress, the synthesis of four proteins was found to be associated with the growth phase in batch culture; three of these proteins had a higher rate of de novo synthesis when the cells entered the solvent production phase. One of the stress-induced proteins, hsp74, was partially purified an found to be immunologically related to
Escherichia coli
heat shock protein Dnak. The similarities of the proteins induced at the onset of solventogenesis and by stress suggest a relationship between the two processes.
Control of the Life Cycle of
Methanosarcina mazei
S-6 by Manipulation of Growth Conditions
Authors: Xun Luying , Boone David R. , Mah Robert A.
Published: January 2020

The morphology of
Methanosarcina mazei
was controlled by magnesium, calcium, and substrate concentrations and by inoculum size; these factors allowed manipulation of the morphology and interconversions between pseudosarcinal aggregates and individual, coccoid cells.
M. mazei
grew as aggregates in medium with a low concentration of catabolic substrate (either 50 mM acetate, 50 mM methanol, or 10 mM trimethylamine) unless Ca
2+
and Mg
2+
concentrations were high. Growth in medium high in Ca
2+
, Mg
2+
, and substrate (i.e., 150 mM acetate, 150 mM methanol, or 40 mM trimethylamine) converted pseudosarcinal aggregates to individual cocci. In such media, aggregates separated into individual cells which continued to grow exclusively as single cells during subsequent transfers. Conversion of single cells back to aggregates was complicated, because conditions which supported the aggregated morphology (e.g., low calcium or magnesium concentration) caused lysis of coccoid inocula. We recovered aggregates from coccoid cells by inoculating serial dilutions into medium high in calcium and magnesium. Cells from very dilute inocula grew into aggregates which disaggregated on continued incubation. However, timely transfer of the aggregates to medium low in calcium, magnesium, and catabolic substrates allowed continued growth as aggregates. We demonstrated the activity of the enzyme (disaggregatase) which caused the dispersion of aggregates into individual cells; disaggregatase was produced not only during disaggregation but also in growing cultures of single cells. Uronic acids, the monomeric constituents of the
Methanosarcina
matrix, were also produced during disaggregation and during growth as coccoids.
Averaging of TNTC counts
Authors: Haas C N , Heller B
Published: January 2020

When plate count methods are used for microbial enumeration, if too-numerous-to-count results occur, they are commonly discarded. In this paper, a method for consideration of such results in computation of an average microbial density is developed, and its use is illustrated by example.
Comparison of bacterial indicators and sampling programs for drinking water systems
Authors: Collin J F , Zmirou D , Ferley J P , Charrel M
Published: January 2020

A total of 48 French villages were selected for a survey of water quality from February 1983 to June 1984 as part of an epidemiological study conducted in the rural area of the Rhône-Alpes region. Water samples were collected and analyzed on a weekly basis in each village. Bacteriological analysis of each water sample included enumeration of standard plate count bacteria, total and thermotolerant coliforms, and fecal streptococci. The water quality regulations are examined as to the analysis frequency, the volume of samples, and the relationship between the various bacterial indicators. Analyzing 300-ml, instead of 100-ml, samples tends to generate better information on single water samples. However, if many samples are analyzed over time from the same community, the value of using large volumes of water samples is diminished. The comparisons between bacterial indicators showed that the information obtained from the various indicators was very similar. However, fecal streptococci had a better predictive value of a negative test than coliforms with respect to the French standards.
Characterization of the Adhesive Holdfast of Marine and Freshwater Caulobacters
Authors: Merker Robert I. , Smit John
Published: January 2020

Caulobacters are prosthecate (stalked) bacteria that elaborate an attachment organelle called a holdfast at the tip of the cellular stalk. We examined the binding of lectins to the holdfasts of 16 marine
Caulobacter
strains and 10 freshwater species or strains by using a panel of fluorescein-conjugated lectins and fluorescence microscopy. The holdfasts of all the marine isolates bound to only wheat germ agglutinin (WGA) and other lectins that bind
N
-acetylglucosamine (GlcNac) residues. The freshwater caulobacters showed more variability in holdfast composition. Some bound only to WGA and comparable lectins as the marine strains did. Others bound additional or other lectins, and some did not bind to the lectins tested. The binding of WGA appeared to involve the regions of the holdfast involved with adhesion; a holdfast bound to WGA was significantly less adhesive to glass. Competition experiments with WGA-binding holdfasts and oligomers of GlcNac demonstrated that trimers of GlcNac (the preferred substrate for WGA binding) were more effective than dimers or monomers in preventing WGA binding to holdfasts, suggesting that stretches of contiguous GlcNac residues occur in the WGA-binding holdfasts. In addition, differences between freshwater and marine holdfasts in the strength of WGA binding were noted. The effect of a number of proteolytic and glycolytic enzymes on holdfast integrity was examined; the proteases had no effect for all caulobacters. None of the glycolytic enzymes had an effect on marine caulobacter holdfasts, but chitinase and lysozyme (both attack oligomers of GlcNac) disrupted the holdfasts of those freshwater caulobacters that bound WGA. Despite some similarity to chitin, holdfasts did not bind Calcofluor and no measurable effects on holdfast production were detectable after cell growth in the presence of diflubenzuron or polyoxin D, inhibitors of chitin synthesis in other systems. Finally, the holdfasts of all caulobacters bound to colloidal gold particles, without regard to the coating used to stabilize the gold particles. This binding was stronger or more specific than WGA binding; treatment with colloidal gold particles prevented WGA binding, but the reverse was not the case.
Biosynthetic relationship among aflatoxins B1, B2, G1, and G2
Authors: Yabe K , Ando Y , Hamasaki T
Published: January 2020

Aspergillus parasiticus NIAH-26, a UV-irradiated mutant of A. parasiticus SYS-4 (NRRL 2999), produces neither aflatoxins nor precursors. When sterigmatocystin (ST) or O-methylsterigmatocystin was fed to this mutant in YES medium, aflatoxins B1 (AFB1) and G1 (AFG1) were produced. When dihydrosterigmatocystin (DHST) or dihydro-O-methylsterigmatocystin was fed to this mold, aflatoxins B2 (AFB2) and G2 (AFG2) were produced. The reactions from ST to AFB1 and DHST to AFB2 were also observed in the cell-free system and were catalyzed stepwise by the methyltransferase and oxidoreductase enzymes. In the feeding experiments of strain NIAH-26, the convertibility from ST to AFB1-AFG1 was found to be remarkably suppressed by the coexistence of DHST in the medium, and the convertibility from DHST to AFB2-AFG2 was also suppressed by the presence of ST. When some other mutants which endogenously produce a small amount of aflatoxins (mainly AFB1 and AFG1) were cultured with DHST, the amounts of AFB1 and AFG1 produced were significantly decreased, whereas AFB2 and AFG2 were newly produced. In similar feeding experiments in which 27 kinds of mutants including these mutants were used, most of the mutants which were able to convert exogenous ST to AFB1-AFG1 were also found to convert exogenous DHST to AFB2-AFG2. These results suggest that the same enzymes may be involved in the both biosynthetic pathways from ST to AFB1-AFG1 and DHST to AFB2-AFG2. The reactions described herein were not observed when the molds had been cultured in the YEP medium.
Cloning of nisin resistance determinant and replication origin on 7.6-kilobase EcoRI fragment of pNP40 from Streptococcus lactis subsp. diacetylactis DRC3
Authors: Froseth B R , Herman R E , McKay L L
Published: January 2020

The nisin resistance determinant and an origin of replication on pNP40, a plasmid of about 60 kilobases that is present in Streptococcus lactis subsp. diacetylactis DRC3, was cloned on a 7.6-kilobase EcoRI fragment. When self-ligated, this fragment existed as an independent replicon (pFM011) and contained a 2.6-kilobase EcoRI-XbaI fragment encoding nisin resistance.
Oxidation of Manganese and Formation of Mn
3
O
4
(Hausmannite) by Spore Coats of a Marine
Bacillus
sp
Authors: Mann S. , Sparks N. H. C. , Scott G. H. E. , de Vrind-de Jong E. W.
Published: January 2020

Isolated spore coats of a marine
Bacillus
species were incubated in 25 mM MnCl
2
at pH 7.5. Manganese precipitates, formed on the coat surfaces, were analyzed by transmission electron microscopy, electron diffraction, and energy-dispersive X-ray spectroscopy. Initially, an amorphous manganese oxide was observed on the coats which recrystallized to hausmannite after prolonged incubation in the MnCl
2
solution. The spore coats catalyze the oxidation of Mn(II) and have no structural influence on the final mineral phase precipitated.
Isolation from a coastal fish of Vibrio hollisae capable of producing a hemolysin similar to the thermostable direct hemolysin of Vibrio parahaemolyticus
Authors: Nishibuchi M , Doke S , Toizumi S , Umeda T , Yoh M , Miwatani T
Published: January 2020

A vibrio isolated from the intestine of a coastal fish was identified as Vibrio hollisae by its biochemical characteristics. The isolate reacted with the gene probe for the thermostable direct hemolysin of Vibrio parahaemolyticus. The hemolysin produced by the isolate from the fish had traits identical to those of the thermostable direct hemolysin-like hemolysin produced by a clinical strain of V. hollisae.
Response in Soil of
Cupriavidus necator
and Other Copper-Resistant Bacterial Predators of Bacteria to Addition of Water, Soluble Nutrients, Various Bacterial Species, or
Bacillus thuringiensis
Spores and Crystals
Authors: Casida L. E.
Published: January 2020

Soil was incubated with various species of bacteria,
Bacillus subtilis
, or
Bacillus thuringiensis
spores and crystals. These were added to serve as potential prey for indigenous, copper-resistant, nonobligate bacterial predators of bacteria in the soil. Alternatively, the soil was incubated with soluble nutrients or water only to cause potential indigenous prey cells to multiply so the predator cells would multiply. All of these incubation procedures caused excessive multiplication of some gram-negative bacteria in soil. Even greater multiplication, however, often occurred for certain copper-resistant bacterial predators of bacteria that made up a part of the gram-negative response. Incubation of the soil with copper per se did not give these responses. In most cases, the copper-resistant bacteria that responded were
Cupriavidus necator,
bacterial predator L-2, or previously unknown bacteria that resembled them. As was the case for
C. necator
and L-2, these new bacteria did not use glucose, had white colonies, produced copper-related growth initiation factor (GIF), and attacked
B. thuringiensis
spores on laboratory media. The results were different, however, when
B. thuringiensis
spores and crystals per se were added to the soil. The copper-resistant bacterial response in the soil did not, to any extent, include
C. necator
-like bacteria. Instead, the main copper-resistant bacterial predators that developed had yellow colonies and did not resemble
C. necator
or L-2 in other ways. They were not seen before, and they did not develop on the addition of
B. subtilis
spores to soil. Apparently, they could not produce a
C. necator
-like GIF. Nevertheless, they did respond very quickly to
B. thuringiensis
spores and crystals in soil, as if a GIF of some sort were involved. These results suggest that, under various conditions of soil incubation, gram-negative bacterial predators of bacteria multiply and that several copper-resistant types among them can be detected, counted, and isolated by plating dilutions of the soil onto media containing excess copper.
Influence of metabolic and physical factors on production of diacetoxyscirpenol by Fusarium sambucinum Fuckel
Authors: Monnet D , Vidal D , Créach O
Published: January 2020

Fusarium sambucinum Fuckel 8099-1 was grown on Czapek-Dox peptone-supplemented medium at 15 degrees C for 14 days, and the cultures were investigated for diacetoxyscirpenol (DAS) production by liquid-liquid extraction and gas chromatography. The addition of 150 mg of sorbic acid, a tricarboxylic acid cycle inhibitor, per liter stimulated both fungal growth and DAS production. Among the beta-hydroxy-beta-methylglutaryl coenzyme A precursors tested, isovaleric acid completely inhibited fungal growth and DAS production, ethyl isovalerate did not support a significant increase in DAS production, and L-leucine partially inhibited DAS production, showing that L-leucine and isovaleric acid catabolisms do not induce trichothecene biosynthesis. Solid particles (cork powder) were necessary for DAS production in stationary cultures but did not influence DAS production in shaken cultures. Shaking strongly stimulated DAS production and fungal growth.
Effect of Pentoses and Pentitols on Fermentation of Hay by Mixed Populations of Ruminal Microorganisms
Authors: Gascoyne Deborah J. , Theodorou Michael K. , Bazin Michael J.
Published: January 2020

Consecutive batch culture, a technique which involves sequential transfer of cultures to fresh medium at regular intervals, was used to establish mixed ruminal-microbial populations in an anaerobic medium containing highly digestible hay. Once volatile fatty acid production was stable, perturbations were imposed in consecutive cultures by the addition of one of each of the following pentoses or analogous pentitols:
l
-arabinose,
d
-lyxose,
d
-ribose,
d
-xylose,
l
-arabitol,
d
-arabitol (lyxitol), ribitol, and xylitol. With the exception of
d
-lyxose, the addition of pentoses caused marked increases in propionate and valerate production, and except for
d
-arabitol, pentitol addition caused increases in butyrate and valerate production. On transfer to and continued incubation in the control medium, volatile fatty acid production reverted to preperturbed levels. The presence of pentitols and pentoses significantly reduced the endpoint pH of cultures and the proportion of hay that was fermented. With all added substrates, the response to the perturbation was at its maximum within one incubation (i.e., within 48 h). Similarly, the variables being monitored all returned to control levels within one incubation. On the basis of these results, it is suggested that changes were related to the need to maintain a redox balance within anaerobic cultures rather than any significant changes in the microbial population that was present.
Effects of Lactic Acid Bacteria and Organic Acids on Growth and Germination of
Bacillus cereus
Authors: Wong Hin-Chung , Chen Ya-Lei
Published: January 2020

Growth and germination of vegetative cells and endospores of
Bacillus cereus
were affected by
Streptococcus lactis, Streptococcus thermophilus, Lactobacillus acidophilus
, and
Lactobacillus bulgaricus
in nonfat milk medium and by salts of organic acids in broth medium. Growth of the lactic acid bacteria was not affected by
B. cereus. B. cereus
increased rapidly to about 10
8
CFU/ml when cells were added at the beginning of growth of lactic acid bacteria; it was inactivated slowly when added after 24 h and rapidly when added after 72 h of lactic acid bacterial growth. Streptococci were more inhibitory to the growth of
B. cereus
than lactobacilli were at 24 h. Spore germination was not affected after 24 h, but it was inhibited after 48 and 72 h of lactic acid bacterial growth. Acetate was more inhibitory to the growth of vegetative cells, while formate was more inhibitory to spore germination. Acetate, formate, and lactate (all at 0.1 M) completely inactivated multiplication of
B. cereus
at pH 6.1, 6.0, and 5.6, respectively. Spores of
B. cereus
were more resistant to these organic acids compared with the resistance of vegetative cells. Formate, lactate, and acetate (all at 0.1 M) caused 50% inhibition of spore germination at pH 4.4, 4.3, and 4.2, respectively.
Escherichia coli
Spheroplast-Mediated Transfer of pBR322 Carrying the Cloned
Ruminococcus albus
Cellulase Gene into Anaerobic Mutant Strain FEM29 by Protoplast Fusion
Authors: Chen Wei , Ohmiya Kunio , Shimizu Shoichi
Published: January 2020

Intergeneric protoplast fusion between
Escherichia coli
HB101 with pBR322 carrying the cloned
o
-(carboxymethyl)cellulase (CMCase) gene of
Ruminococcus albus
(Pro
-
Leu
-
Ap
r
Km
s
) and an anaerobic mutant strain, FEM29 (Trp
-
His
-
Ap
s
Km
r
), with dehydrodivanillin-degrading activity was performed in the presence of 40% polyvinyl alcohol 300 under aerobic and anaerobic conditions to transfer the cloned cellulase gene into the mutant. The mutant FEM29 had a unique property. When it was incubated in liquid medium with 1% glucose and sucrose, protoplasts could be produced autogenously and regenerated on the agar slant.
E. coli
spheroplasts formed from a plasmid-amplified overnight culture after 10 min of treatment with lysozyme (20 μg/ml) in a hypertonic solution (0.01 M Tris hydrochloride [pH 7.5], 0.4 M mannitol). Protoplast regeneration rates of FEM29 and HB101 were 30 and 83%, respectively, on the agar-yeast extract medium. Ap
r
Km
r
fusants were obtained at high frequency: 1.7 × 10
−2
anaerobically and 8.2 × 10
−3
aerobically. These fusants showed 23 to 57% of CMCase and dehydrodivanillin-degrading activities, respectively, as compared with parental strains. All the fusants isolated were gram-negative rods with main phenotypes such as urease and catalase activities as in HB101 and esterase and chymotrypsin activities as in FEM29. Southern hybridization experiments suggested that pBR322 with the cloned CMCase gene existed autonomously in the fusant cells. This is the first report describing transfer of pBR322 with a cloned cellulase gene into an anaerobic mutant by polyvinyl alcohol-mediated fusion with an
E. coli
spheroplast.
Effect of Calcium Cation on Plating Efficiency of the Sulfate-Reducing Bacterium
Desulfovibrio vulgaris
Authors: Singleton Rivers , Ketcham Robert B. , Campbell L. Leon
Published: January 2020

The presence of Ca
2+
(concentration, ca. 0.4 mM) in the growth medium causes cells of
Desulfovibrio vulgaris
(Hildenborough) to aggregate, leading to a decrease in plating efficiency. When the Ca
2+
concentration in the medium was reduced 20-fold, cell aggregation did not occur and the plating efficiency increased from an initial value of 34% to a final value of 56%.
Production and characterization of monoclonal antibodies to the macrocyclic trichothecene roridin A
Authors: Hack R , Märtlbauer E , Terplan G
Published: January 2020

Two murine monoclonal antibodies to the macrocyclic trichothecene roridin A are described. Screening for antibody production was performed on absorbed anti-mouse immunoglobulin serum as double-antibody solid phase, and further characterization was done on affinity-purified anti-mouse IgG serum. The antibodies, designated 5G11 and 4H10, had affinity constants for roridin A of 9.25 X 10(7) and 1.7 X 10(7) liters/mol, respectively. In monoclonal antibody-based direct enzyme immunoassays, these IgG1 antibodies had detection limits for roridin A of 0.4 ng/ml (0.02 ng per assay) and 1.8 ng/ml (0.09 ng per assay), respectively. Both antibodies were most specific for the tested macrocyclic trichothecenes. The relative cross-reactivities of antibody 5G11 with roridin A, roridin J, verrucarin A, satratoxin G, and satratoxin H were 100.0, 43.8, 16.7, 3.7, and 18.9%, respectively; for antibody 4H10 they were 100.0, 6.3, 64.0, 4.4, and 4.9%, respectively.
Agarose soy casein digest medium for replacement of blood agar for potency determinations of live Pasteurella vaccines
Authors: Rebers P A , Christianson G G , Laird G A , Symanowski J
Published: January 2020

Blood agar, prepared with Trypticase (BBL Microbiology Systems, Cockeysville, Md.) soy agar and 5% defibrinated bovine blood, is used for testing the potency of live Pasteurella multocida and Pasteurella haemolytica vaccines, but its potential for variation makes it undesirable to use in a standard assay method. Tests done with RPMI 1640 and Trypticase soy medium indicated that the benefits obtained by adding defibrinated blood to the Trypticase soy agar medium were more likely due to neutralization of toxic components than to the presence of transferrin or iron as growth factors. Reduction of toxic components in the Trypticase soy agar medium was accomplished by replacing agar with agarose and by autoclaving glucose as a separate solution to produce the replacement medium. The replacement medium was prepared by autoclaving three separate solutions--Trypticase soy broth without glucose; glucose; and agarose--cooling to 55 degrees C, and mixing and then pouring the mixtures into petri dishes. The growth obtained with this medium as judged by determination of the number of CFU and the colony sizes of P. multocida or P. haemolytica was equal to or better than those obtained with blood agar.
Diversity within Serogroups of
Rhizobium leguminosarum
biovar
viceae
in the Palouse Region of Eastern Washington as Indicated by Plasmid Profiles, Intrinsic Antibiotic Resistance, and Topography
Authors: Brockman F. J. , Bezdicek D. F.
Published: January 2020

Serology, plasmid profiles, and intrinsic antibiotic resistance (IAR) were determined for 192 isolates of
Rhizobium leguminosarum
biovar
viceae
from nodules of peas (
Pisum sativum
L.) grown on the south slope and bottomland topographic positions in eastern Washington State. A total of 3 serogroups and 18 plasmid profile groups were identified. Nearly all isolates within each plasmid profile group were specific for one of the three serogroups. Cluster analysis of IAR data showed that individual clusters were dominated by one serogroup and by one or two plasmid profile groups. Plasmid profile analysis and IAR analysis grouped 72% of the isolates similarly. Most plasmid profile groups and several IAR clusters favored either the south slope or the bottomland topographic position. These findings show that certain intraserogroup strains possess a greater competitiveness for nodulation and/or possess a greater ability to survive in adjacent soil environments.
Bacterial hydrophobicity, an overall parameter for the measurement of adhesion potential to soil particles
Authors: Stenström T A
Published: January 2020

The adhesion of Salmonella typhimurium to the mineral particles quartz, albite, feldspar, and magnetite was shown to correlate with the hydrophobicity of the cell surface as measured by hydrophobic interaction chromatography. The same effects were also seen for seven other selected test strains, including Streptococcus faecalis, Streptococcus faecium, Escherichia coli, Citrobacter freundii, Shigella sonnei, and Shigella boydii. When the test strain of Salmonella typhimurium, was repeatedly cultivated in Luria broth, thus selecting for different degrees of fimbriation and roughness of the cell surface, varied cell hydrophobicity but constant negative and positive charge values were obtained. High hydrophobicity values always coincided with enhanced adhesion to the mineral particles. The negative charge of the bacterial surface as measured by electrostatic interaction chromatography appeared to play no role in the adhesion event. However, the positive charges on the cell surface contributed to the adhesion process. This was especially evident for cells exhibiting a high degree of hydrophobicity. Alteration of the pH between 4 and 9 did not significantly affect the adhesion process.
Characterization of Xylose Uptake in the Yeasts
Pichia heedii
and
Pichia stipitis
Authors: Does Amy L. , Bisson Linda F.
Published: January 2020

The kinetics of xylose uptake were investigated in the efficient xylose fermenter
Pichia stipitis
and in the more readily genetically manipulated, strictly respiratory yeast
Pichia heedii.
Both yeasts demonstrated more than one xylose uptake system, differing in substrate affinity. The

K
m

of high-affinity xylose uptake in both organisms was similar to that of the efficient high-affinity glucose uptake system of
Saccharomyces cerevisiae.
In
P. heedii
, low-affinity xylose uptake was enhanced with growth on 2% but not 0.05% xylose and high-affinity uptake was reduced. In contrast to glucose uptake, xylose uptake in
P. heedii
was inhibited by dinitrophenol. Dinitrophenol inhibited both glucose and xylose uptake by
P. stipitis.
Glucose uptake was not inhibited by a 100-fold molar excess of xylose in
P. heedii.
It is suggested that xylose uptake in
P. heedii
is via a carrier system(s) distinct from those for glucose uptake.
Construction of a lactococcal expression vector: expression of hen egg white lysozyme in Lactococcus lactis subsp. lactis
Authors: van de Guchte M , van der Vossen J M , Kok J , Venema G
Published: January 2020

A pair of vectors for expression of heterologous genes in Lactococcus lactis was constructed. In addition to an origin of replication that has a broad host range, these vectors contain a multiple cloning site flanked by gene expression signals originating from L. lactis subsp. cremoris Wg2. The two vectors, about 3.7 kilobase pairs in size, differ only in the type of antibiotic resistance they confer to their hosts. pMG36 carries a kanamycin resistance marker, which was replaced by an erythromycin resistance marker in pMG36e. As an example of the use of these vectors, the hen egg white lysozyme-coding sequence was inserted. A fusion protein of the expected size was detected in a transformed L. lactis subsp. lactis strain by using Western blotting (immunoblotting).
Immunoelectron microscopic demonstration of an esterase on the outer membrane of Xanthomonas maltophilia
Authors: Debette J , Prensier G
Published: January 2020

Xanthomonas maltophilia (later synonym of Pseudomonas maltophilia), an ubiquitous species, is known to show proteolytic and lipolytic activities. A cell-bound esterase which hydrolyzes beta-naphthyl acetate during growth has been extracted from a strain isolated from soil. Because of its strongly hydrophobic character, the enzyme could be efficiently solubilized only by Triton X-100. This nonionic detergent must be added in polyacrylamide gels to permit migration. Polyclonal rabbit antibodies raised against the Triton-soluble esterase complex were used to localize the enzyme at the ultrastructural level. Electron microscopy of cell sections of this organism and immunogold labeling demonstrated that the enzyme was located on the outer membrane. Such an envelope-bound esterase may produce assimilable substrates for X. maltophilia which can grow in various environments.
Lasalocid-catalyzed proton conductance in Streptococcus bovis as affected by extracellular potassium
Authors: Schwingel W R , Bates D B , Denham S C , Beede D K
Published: January 2020

The effect of extracellular potassium on lasalocid-catalyzed proton conductance in Streptococcus bovis 24 was measured by using the fluorescent probe 9-aminoacridine. Increasing external potassium concentration resulted in decreased proton flux into S. bovis cells exposed to the ionophore. These results suggest that lasalocid catalyzes K+/H+ exchange diffusion in S. bovis cells.
Chemokinetic Motility Responses of the Cyanobacterium
Oscillatoria terebriformis
Authors: Richardson Laurie L. , Castenholz Richard W.
Published: January 2020

Oscillatoria terebriformis,
a gliding, filamentous, thermophilic cyanobacterium, exhibited an inhibition of gliding motility upon exposure to fructose. The observed response was transient, and the duration of nonmotility was directly proportional to the concentration of fructose. Upon resumption of motility, the rate of motility was also inversely proportional to the concentration of fructose. Sulfide caused a similar response. The effect of sulfide was specific and not due to either anoxia or negative redox potential. Exposure to glucose, acetate, lactate, or mat interstitial water did not elicit any motility response.
Use of nutrient response techniques to assess the effectiveness of chlorination of rapid sand filter gravel
Authors: Lytle M S , Adams J C , Dickman D G , Bressler W R
Published: January 2020

A direct viable counting method was used to rapidly assess the effectiveness of chlorination of biofilms on rapid sand filter gravel. A total of 50% of the cells were nutrient responsive after exposure to 0.5 mg of chlorine per liter, while this value was 25% after exposure to 25 mg of chlorine per liter. A large variation was seen in the numbers of nutrient-responsive cells on different rocks. More cells attached to the sandblasted side of marbles than to the smooth side, but there was no difference in eight of nine cases in the proportion of survival to chlorination between the two different sides. The effectiveness of chlorination appeared to be influenced by the species of bacterium in the biofilm.
Comparison of methods for enumeration of selected coliforms exposed to ozone
Authors: Adams J C , Lytle M S , Dickman D G , Foster D H , Connell J P , Bressler W R
Published: January 2020

mT7 medium performed no better than m-Endo medium in enumerating cells of Escherichia coli and Citrobacter freundii exposed to ozone. Also, there was no difference in the plate count of heterotrophic bacteria in ozonated raw water determined on modified Henrici agar or R2A agar. Statistically significant differences were seen between bacteria and the type of water in which they were suspended during ozonation.
Photodynamic Production of Superoxide In Vitro by Altertoxins in the Presence of Reducing Agents
Authors: Hartman Philip E. , Suzuki Carolyn K. , Stack Michael E.
Published: January 2020

Superoxide production by the three 4,9-dihydroxyperylene-3,10-quinone fungal toxins, altertoxins I, II, and III, was stimulated on illumination with broad-spectrum light. As determined previously for cercosporin, superoxide production by illuminated altertoxins was increased by the addition of the reducing substances ergothioneine or urate; ascorbate also effectively increased superoxide production. Illuminated urate alone engendered some superoxide production.
Stochastic Models of Soil Denitrification
Authors: Parkin T. B. , Robinson J. A.
Published: January 2020

Soil denitrification is a highly variable process that appears to be lognormally distributed. This variability is manifested by large sample coefficients of variation for replicate estimates of soil core denitrification rates. Deterministic models for soil denitrification have been proposed in the past, but none of these models predicts the approximate lognormality exhibited by natural denitrification rate estimates. In this study, probabilistic (stochastic) models were developed to understand how positively skewed distributions for field denitrification rate estimates result from the combined influences of variables known to affect denitrification. Three stochastic models were developed to describe the distribution of measured soil core denitrification rates. The driving variables used for all the models were denitrification enzyme activity and CO
2
production rates. The three models were distinguished by the functional relationships combining these driving variables. The functional relationships used were (i) a second-order model (model 1), (ii) a second-order model with a threshold (model 2), and (iii) a second-order saturation model (model 3). The parameters of the models were estimated by using 12 separate data sets (24 replicates per set), and their abilities to predict denitrification rate distributions were evaluated by using three additional independent data sets of 180 replicates each. Model 2 was the best because it produced distributions of denitrification rate which were not significantly different (
P
> 0.1) from distributions of measured denitrification rates. The generality of this model is unknown, but it accurately predicted the mean denitrification rates and accounted for the stochastic nature of this variable at the site studied. The approach used in this study may be applicable to other areas of ecological research in which accounting for the high spatial variability of microbiological processes is of interest.
Evaluation of the Autoanalysis Colilert test for detection and enumeration of total coliforms
Authors: Covert T C , Shadix L C , Rice E W , Haines J R , Freyberg R W
Published: January 2020

The Autoanalysis Colilert (AC) test was compared with the membrane filter (MF), 10-tube multiple-tube fermentation (MTF) technique, and the presence-absence test as described in Standard Methods for the Examination of Water and Wastewater for the detection and enumeration of total coliforms in water. The methods were evaluated with 31 samples from seven different sources. Each sample was analyzed by each of the techniques, using replicate 100-ml sample volumes. A total of 582 confirmed tubes were positive by the MTF test, and 533 tubes were positive by the AC test. Statistical analysis of the most-probable-number comparability data showed a statistically significant difference in the number of positive tubes, with the MTF test resulting in more positive tubes. There were no statistically significant differences in precision between the two methods. All the methods were comparable in detection of total coliforms. Levels of heterotrophic bacteria generally encountered in drinking water did not interfere with detection or enumeration of coliforms by the AC test.
Purification and characterization of endoglucanase C of Cellulomonas fimi, cloning of the gene, and analysis of in vivo transcripts of the gene
Authors: Moser B , Gilkes N R , Kilburn D G , Warren R A , Miller R C
Published: January 2020

Two nonglycosylated endoglucanases which bind to Sephadex were purified from culture supernatants of Cellulomonas fimi grown on microcrystalline cellulose. Their Mrs were 120,000 and 130,000. The N-terminal amino acid sequences of the enzymes were identical, suggesting that the enzymes were related. A DNA fragment encoding this N-terminal sequence was cloned in Escherichia coli. The nucleotide sequence corresponding to the N-terminal amino acid sequence was preceded by a sequence encoding a typical leader peptide. Transcripts hybridizing to the cloned fragment were detected in total RNA isolated from C. fimi cells grown on carboxymethyl cellulose but not from cells grown on glycerol or glucose. Transcription started at a cluster of sites 53 to 59 nucleotides upstream of a GUG translation initiation codon and terminated at either of two closely spaced C residues immediately downstream of a region of potential secondary structure. The size of the transcript was approximately 3.5 kilobases, sufficient to encode a polypeptide of 130 kilodaltons. The 130-kilodalton polypeptide is designated endoglucanase C (CenC), and the gene encoding it is designated cenC.
Production of
Leuconostoc oenos
Biomass under pH Control
Authors: Champagne Claude P. , Gardner Nancy , Doyon Gilles
Published: January 2020

Leuconostoc oenos
was grown on apple juice-based media. The effect of pH control on metabolism and biomass production was studied. Without pH control,
L. oenos
acidified the apple juice media to approximately pH 3.6. More than 75% of the malic acid was used under these conditions, but less than half of the carbohydrates was assimilated. Under pH control, biomass yields increased by 60%; most of the malic acid was used, but high levels of unfermented carbohydrates remained. The addition of tomato juice, vitamins, nucleotides, Mn
+
, and malic acid did not permit further increases in the cell counts; however, malic acid did induce further acidification. Growth without pH control favored a more homofermentative metabolism. Biomass production was higher in filter-sterilized apple juice media compared with that in the autoclaved media.
Transformation of Bacillus polymyxa with plasmid DNA
Authors: Mallonee D H , Speckman R A
Published: January 2020

A plasmid transformation system was developed for Bacillus polymyxa ATCC 12321 and derivatives of this strain. The method utilizes a penicillin-treated-cell technique to facilitate uptake of the plasmid DNA. Low-frequency transformation (10(-6) per recipient cell) of plasmids pC194, pBD64, and pBC16 was accomplished with this method. Selection for the transformants was accomplished on both hypertonic and nonhypertonic selective media, with the highest rates of recovery occurring on a peptone-glucose-yeast extract medium containing 0.25 M sucrose. Several additional plasmids were shown to be capable of transferring their antibiotic resistance phenotypes to B. polymyxa through the use of a protoplast transformation procedure which allowed for a more efficient transfer of the plasmid DNA. However, cell walls could not be regenerated on the transformed protoplasts, and the transformants could not be subcultured from the original selective media.
Use of degenerate oligonucleotides for amplification of the nifH gene from the marine cyanobacterium Trichodesmium thiebautii
Authors: Zehr J P , McReynolds L A
Published: January 2020

Trichodesmium spp. are marine filamentous, nonheterocystous, nitrogen-fixing cyanobacteria which are an important component of marine ecosystems. This organism has never been maintained in axenic culture, and there has remained some doubt as to the identity of the organism responsible for nitrogen fixation in Trichodesmium aggregates. By using degenerate oligonucleotide primers, it has been possible to amplify, clone, and sequence a segment of the nifH gene from a natural assemblage of Trichodesmium thiebautii. Examination of the DNA and presumed amino acid sequence shows that the gene is most closely related to that of Anabaena spp. and therefore is most likely a cyanobacterial nifH gene. The use of degenerate oligonucleotides, in concert with the polymerase chain reaction, can be a powerful tool for the cloning and sequencing of a variety of genes from microorganisms in the environment.
Reductive dehalogenation of dichloroanilines by anaerobic microorganisms in fresh and dichlorophenol-acclimated pond sediment
Authors: Struijs J , Rogers J E
Published: January 2020

We investigated the transformation of 2,4-dichloroaniline (2,4-DiCA) and 3,4-DiCA to monochloroanilines (CA) in anaerobic pond sediment. Dechlorination of 3,4-DiCA to 3-CA started after a lag period of 3 weeks and was complete after an additional 5 weeks. Although 2,4-DiCA disappeared over 8 weeks, the appearance of a CA product could not be detected. In contrast, anaerobic bacteria in pond sediment acclimated to dehalogenate 2,4-dichlorophenol (2,4-DiCP) or 3,4-DiCP rapidly dechlorinated 2,4-DiCA and 3,4-DiCA without any lag time. By comparison, anaerobic sediment bacteria acclimated to 3,4-DiCA rapidly degraded 3,4-DiCP without a lag. In all cases, the CA products were stable for the duration of the experiments. It is concluded that cross-acclimation occurred.
Development of a Solid Medium for Growth and Isolation of Axenic
Microcystis
Strains (Cyanobacteria)
Authors: Shirai Makoto , Matumaru Katsumi , Ohotake Akio , Takamura Yoshichika , Aida Tokujiro , Nakano Masayasu
Published: January 2020

Solid media on a base of B-12 or CB medium with agarose or agarose of low melting temperature were developed for the cultivation of
Microcystis
species. The media with 0.4% gel showed the highest number of CFU, and increasing the gel concentration resulted in a reduction of the number of CFU. There was no difference in the numbers of CFU between pour and spread plates made of the solid media. By using the solid media, 31 clones of
Microcystis
species were isolated from natural blooms in Lake Kasumigaura, and 5 axenic strains (1 of
M. wesenbergii
and 4 of
M. aeruginosa
) were established from the clones.