bluuebunny/crossref_metadata_2025 huggingface dataset:
Biodelignification of Lemon Grass and Citronella Bagasse by White-Rot Fungi
Authors: Rolz C. , de Leon R. , de Arriola M. C. , de Cabrera S.
Published: January 2020

Twelve white-rot fungi were grown in solid-state culture on lemon grass (
Cymbopogon citratus
) and citronella (
Cymbopogon winterianus
) bagasse. The two lignocellulosic substrates had 11% permanganate lignin and a holocellulose fraction of 58%. After 5 to 6 weeks at 20°C, nine fungi produced a solid residue from lemon grass with a higher in vitro dry matter enzyme digestibility than the original bagasse; seven did the same for citronella. The best fungus for both substrates was
Bondarzewia berkeleyi
; it increased the in vitro dry matter enzyme digestibility to 22 and 24% for lemon grass and citronella, respectively. The increases were correlated with weight loss and lignin loss. All fungi decreased lignin contents: 36% of the original value for lemon grass and 28% for citronella. Practically all fungi showed a preference for hemicellulose over cellulose.
Method for flow cytometric detection of Listeria monocytogenes in milk
Authors: Donnelly C W , Baigent G J
Published: January 2020

This report describes a method for the detection of Listeria monocytogenes in raw milk by flow cytometric analysis of fluorescently labeled bacterial populations. The use of immunofluorescence in combination with measures of DNA content by propidium iodide labeling and size by light scattering enabled specific identification of L. monocytogenes from Streptococcus faecalis, Streptococcus agalactiae, Streptococcus uberis, Staphylococcus epidermidis, and Staphylococcus hyicus. Additional specific resolution of L. monocytogenes populations was achieved through selective enrichment of raw milk in Listeria enrichment broth. These procedures should permit the rapid screening of milk and other food samples for L. monocytogenes and eliminate many of the short-comings associated with conventional fluorescent-antibody procedures.
Effect of nutrient deprivation on lipid, carbohydrate, DNA, RNA, and protein levels in Vibrio cholerae
Authors: Hood M A , Guckert J B , White D C , Deck F
Published: January 2020

The response of Vibrio cholerae to low nutrient levels was determined by measuring the concentrations of lipids, carbohydrates, DNA, RNA, and proteins over a 30-day starvation period. Ultrastructural integrity was observed by transmission electron microscopy. Total lipids and carbohydrates declined rapidly within the first 7 days, while DNA and protein exhibited a more constant decline over the 30 days of starvation. In contrast, RNA showed little decrease upon starvation. Although neutral lipids were lost, the percentage of neutral lipids did not decline as rapidly as the phospholipids. Detectable levels of poly-beta-hydroxybutyrate disappeared completely by 7 days. Carbohydrate profiles revealed the relative loss of the five-carbon sugar ribose and N-acetylglucosamine and a relative increase in the total six-carbon sugars, especially glucose. Morphologically, ribosomes appeared to exhibit no structural change, while inclusion bodies and mesosomelike structures disappeared completely, and cell wall and membrane integrity was lost. The data suggest that V. cholerae differs somewhat from other marine vibrios in its response to low nutrients but shares some characteristics in common with them. The data also suggest that certain lipids and carbohydrates may provide the endogenous energy sources needed for dormancy preparation and cell maintenance under nutrient starvation.
Phospholipid ester-linked fatty acid profile changes during nutrient deprivation of Vibrio cholerae: increases in the trans/cis ratio and proportions of cyclopropyl fatty acids
Authors: Guckert J B , Hood M A , White D C
Published: January 2020

The phospholipid ester-linked fatty acids of 0-day-, 7-day-, and 30-day-starved cultures of Vibrio cholerae were compared. Statistically significant trends were noted in the fatty acid profiles as the cells starved. The amount of the cis-monoenoic fatty acids declined (e.g., 16:1 omega 7c: 0 day, 39%; 7 day, 18%; 30 day, 11%). In contrast, the saturated fatty acids, the cyclopropyl derivatives of the cis-monoenoic fatty acids, and trans-monoenoic fatty acids increased during starvation. For instance, the amounts of 16:1 omega 7t were: 0 day, 1%; 7 day, 13%; 30 day, 17%; which increased the trans/cis ratio for 16:1 omega 7 from 0.02 (0 day) to 0.70 (7 day) to 1.56 (30 day). This may be due to the reported high turnover rates of cis-monoenoic fatty acids of membrane phospholipids and the availability of enzymes for the metabolism of these isomers. During starvation-induced phospholipid loss, the cis-monoenoic fatty acids would, therefore, be preferentially utilized. The ability to either synthesize trans-monoenoic acids (which are not easily metabolized by bacteria) or modify the more volatile cis-monoenoic acids to their cyclopropyl derivatives may be a survival mechanism which helps maintain a functional (although structurally altered) membrane during starvation-induced lipid utilization. In addition, a trans/cis fatty acid ratio significantly greater than that reported for most bacterial cultures and environmental samples (less than 0.1) may be used as a starvation or stress lipid index. Such a ratio could help determine the nutritional status of ultramicrobacteria and other reported dormant cells in natural aquatic environments.(ABSTRACT TRUNCATED AT 250 WORDS)
Large-Scale Production of
Rhizobium meliloti
on Whey
Authors: Bissonnette N. , Lalande R. , Bordeleau L. M.
Published: January 2020

Whey, a by-product of the cheese industry, can sustain the growth of fast-growing rhizobia. To avoid any latency of growth, rhizobial inoculum must be prepared under inducing conditions. In unsupplemented whey, the number of cells of
Rhizobium meliloti
Balsac reached 5 × 10
9
CFU/ml in 48 h of incubation. This is comparable to the yield obtained with yeast-mannitol broth, the standard medium for the growth of rhizobia. In raw whey supplemented with yeast extract (1.0 g/liter) and phosphate (0.5 g/liter), the number of cells reached 10
10
CFU/ml in 48 h of incubation. This is a twofold increase compared with the population normally obtained in industrial production. Whey represents a relatively inexpensive and efficient substrate medium for the large-scale production of fast-growing rhizobia.
Alteration of a Salt Marsh Bacterial Community by Fertilization with Sewage Sludge
Authors: Hamlett Nancy V.
Published: January 2020

The effects of long-term fertilization with sewage sludge on the aerobic, chemoheterotrophic portion of a salt marsh bacterial community were examined. The study site in the Great Sippewissett Marsh, Cape Cod, Mass., consisted of experimental plots that were treated with different amounts of commercial sewage sludge fertilizer or with urea and phosphate. The number of CFUs, percentage of mercury- and cadmium-resistant bacteria, and percentage of antibiotic-resistant bacteria were all increased in the sludge-fertilized plots. Preliminary taxonomic characterization showed that sludge fertilization markedly altered the taxonomic distribution and reduced diversity within both the total heterotrophic and the mercury-resistant communities. In control plots, the total heterotrophic community was fairly evenly distributed among taxa and the mercury-resistant community was dominated by
Pseudomonas
spp. In sludge-fertilized plots, both the total and mercury-resistant communities were dominated by a single
Cytophaga
sp.
Comparative analysis of different Pseudomonas strains that degrade cinnamic acid
Authors: Andreoni V , Bestetti G
Published: January 2020

Strains of Pseudomonas stutzeri (CINNS) and Pseudomonas putida (CINNP and CINNW) isolated from soil with cinnamic acid as the sole carbon source were found to be simultaneously adapted to grow on phenylpropionic and p-hydroxybenzoic acids. In cinnamic acid-grown cultures, phenylpropionic acid was isolated. A catabolic plasmid of approximately equal to 75 kilobase pairs encoding the metabolism of cinnamic acid was found in strains CINNP and CINNS.
Growth of Fast- and Slow-Growing Rhizobia on Ethanol
Authors: Sadowsky Michael J. , Bohlool B. Ben
Published: January 2020

Free-living soybean rhizobia and
Bradyrhizobium
spp. (lupine) have the ability to catabolize ethanol. Of the 30 strains of rhizobia examined, only the fast- and slow-growing soybean rhizobia and the slow-growing
Bradyrhizobium
sp. (lupine) were capable of using ethanol as a sole source of carbon and energy for growth. Two strains from each of the other
Rhizobium
species examined (
R. meliloti, R. loti
, and
R. leguminosarum
biovars
phaseoli, trifolii
, and
viceae
) failed to grow on ethanol. One
Rhizobium fredii
(fast-growing) strain, USDA 191, and one (slow-growing)
Bradyrhizobium japonicum
strain, USDA 110, grew in ethanol up to concentrations of 3.0 and 1.0%, respectively. While three of the
R. fredii
strains examined (USDA 192, USDA 194, and USDA 205) utilized 0.2% acetate, only USDA 192 utilized 0.1%
n
-propanol. None of the three strains utilized 0.1% methanol, formate, or
n
-butanol as the sole carbon source.
Associative Nitrogen Fixation by
Klebsiella
spp.: Adhesion Sites and Inoculation Effects on Grass Roots
Authors: Haahtela Kielo , Laakso Tuula , Korhonen Timo K.
Published: January 2020

Adhesion sites on grass roots for
Klebsiella
strains carrying type 3 or type 1 fimbriae or both were determined. Adhesion of the strains to the roots of
Poa pratensis
and
Festuca rubra
was highly localized; the bacteria adhered strongly to root hairs and with a markedly lower efficiency to the surface of the zone of elongation and to the root cap mucilage. No adhesion to the epidermal cells between root hairs was observed. The adhesion sites were identical for the type 3- and 1-fimbriated bacteria and for
P. pratensis, F. rubra
, and
Trifolium pratense.
Inoculation of
P. pratensis
seedlings with
Klebsiella pneumoniae
strain As resulted in morphological changes in plant roots. The roots of infected plants were heavily covered with root hairs, which often were deformed and branched.
Manganese Oxidation by Spores and Spore Coats of a Marine
Bacillus
Species
Authors: de Vrind Johannes P. M. , de Vrind-de Jong Elisabeth W. , de Voogt Jan-Willem H. , Westbroek Peter , Boogerd Fred C. , Rosson Reinhardt A.
Published: January 2020

Bacillus
sp. strain SG-1 is a marine bacterial species isolated from a near-shore manganese sediment sample. Its mature dormant spores promote the oxidation of Mn
2+
to MnO
2
. By quantifying the amounts of immobilized and oxidized manganese, it was established that bound manganese was almost instantaneously oxidized. When the final oxidation of manganese by the spores was partly inhibited by NaN
3
or anaerobiosis, an equivalent decrease in manganese immobilization was observed. After formation of a certain amount of MnO
2
by the spores, the oxidation rate decreased. A maximal encrustment was observed after which no further oxidation occurred. The oxidizing activity could be recovered by reduction of the MnO
2
with hydroxylamine. Once the spores were encrusted, they could bind significant amounts of manganese, even when no oxidation occurred. Purified spore coat preparations oxidized manganese at the same rate as intact spores. During the oxidation of manganese in spore coat preparations, molecular oxygen was consumed and protons were liberated. The data indicate that a spore coat component promoted the oxidation of Mn
2+
in a biologically catalyzed process, after adsorption of the ion to incipiently formed MnO
2
. Eventually, when large amounts of MnO
2
were allowed to accumulate, the active sites were masked and further oxidation was prevented.
Azolla filiculoides
Nitrogenase Activity Decrease Induced by Inoculation with
Chlamydomonas
sp
Authors: Habte Mitiku
Published: January 2020

Experiments were conducted to determine the influence of
Chlamydomonas
sp. on nitrogen fixation (C
2
H
2
→ C
2
H
4
) in
Azolla filiculoides
and on the nitrogen fixation and growth of free-living
Anabaena azollae
2B organisms. Inoculation of azolla medium with
Chlamydomonas
sp. was associated with decreased nitrogenase activity in
A. filiculoides
and with increases in the density of a fungal population identified as
Acremonium
sp. Subsequent inoculation of azolla medium with this fungus was also accompanied by a significant decrease in nitrogenase activity of
A. filiculoides
. However, the extent of depression of nitrogenase activity was significantly higher when azolla medium was inoculated with
Chlamydomonas
sp. than when it was inoculated with
Acremonium
sp. Inoculation of nitrogen-free Stanier medium with either
Acremonium
sp. or
Chlamydomonas
sp. did not adversely affect the growth or nitrogenase activity of free-living
A. azollae
. Decreased nitrogenase activity in
A. filiculoides
is apparently related to the adverse influence of the green alga and the fungus on the macrosymbiont. The mechanisms that might be involved are discussed.
Bacteriocinlike Activity within the Genus
Thermus
Authors: Becker Richard J. , Becker Deborah A. , Starzyk Marvin J.
Published: January 2020

Members of the genus
Thermus
were examined for the presence of bacteriocinlike inhibitory activity. Testing was done by the deferred antagonism technique. Antagonistic activity, as evidenced by zones of inhibition, was expressed by
Thermus rubens
against all other
Thermus
strains tested.
T. rubens
itself was immune to this activity. Plasmid analysis of
T. rubens
revealed the presence of one plasmid of approximately 64 megadaltons.
Novel Actinomycete Isolated from Bulking Industrial Sludge
Authors: White Johanna M. , Labeda David P. , Lechevalier Mary P. , Owens James R. , Jones Daniel D. , Gauthier Joseph J.
Published: January 2020

A novel actinomycete was the predominant filamentous microorganism in bulking activated sludge in a bench-scale reactor treating coke plant wastewater. The bacterium was isolated and identified as an actinomycete that is biochemically and morphologically similar to
Amycolatopsis orientalis
; however, a lack of DNA homology excludes true relatedness. At present, the isolate (NRRL B 16216) cannot be assigned to the recognized taxa of actinomycetes.
Isolation from swine feces of a bacterium which decarboxylates p-hydroxyphenylacetic acid to 4-methylphenol (p-cresol)
Authors: Ward L A , Johnson K A , Robinson I M , Yokoyama M T
Published: January 2020

An obligate anaerobe has been isolated from swine feces which decarboxylates p-hydroxyphenylacetic acid to 4-methylphenol (p-cresol). The bacterium was an ovoid rod, gram positive, nonsporeforming, and nonmotile. Lactate and acetate were major end products of glucose fermentation. Based on its characteristics, the bacterium is tentatively assigned to the genus Lactobacillus.
Identification of environmental Vibrio vulnificus isolates with a DNA probe for the cytotoxin-hemolysin gene
Authors: Morris J G , Wright A C , Roberts D M , Wood P K , Simpson L M , Oliver J D
Published: January 2020

We screened 44 lactose-positive Vibrio strains isolated from the marine environment for homology with a 3.2-kilobase DNA fragment encoding the Vibrio vulnificus cytotoxin-hemolysin gene. All 29 marine isolates identified as V. vulnificus on the basis of numerical taxonomy and DNA-DNA hybridization studies hybridized with the cytotoxin gene probe, as did all V. vulnificus reference strains. Homologous gene sequences were identified in no other lactose-positive marine vibrio isolates nor in 10 other Vibrio species.
Role of Carbon Dioxide in Catabolism of Propane by “
Nocardia paraffinicum
” (
Rhodococcus rhodochrous
)
Authors: MacMichael Gregory J. , Brown Lewis R.
Published: January 2020

The catabolism of propane by “
Nocardia paraffinicum
” (
Rhodococcus rhodochrous
) has been shown to involve CO
2
fixation after its oxidation to propionic acid. “
N. paraffinicum
” failed to grow on either propane or 1-propanol in the absence of CO
2
. The rate of propane utilization was directly related to the initial CO
2
concentration, and Warburg respirometry suggested that CO
2
was required for the catabolism of 1-propanol, propionaldehyde, and propionate but not for 2-propanol. These data also suggested that the predominant pathway for the utilization of propane by “
N. paraffinicum
” was through 1-propanol. The use of [2-
14
C]propane and
14
CO
2
confirmed the catabolism of propane and the fixation of CO
2
. Through the use of these isotopes and the pyruvate carboxylase inhibitor sodium arsenite, the labeled 2,4-dinitrophenylhydrazine derivative of pyruvate was trapped and isolated via thin-layer chromatography. The trapping of [
14
C]pyruvate in this manner was considered to be indicative of the presence of the methylmalonyl coenzyme A pathway for CO
2
fixation.
Effect of extracellular pH on growth and proton motive force of Bacteroides succinogenes, a cellulolytic ruminal bacterium
Authors: Russell J B
Published: January 2020

The utilization of cellulose or cellobiose by Bacteroides succinogenes S85 was severely inhibited at pH values of less than 5.7. Since low pH inhibited the utilization of both cellobiose and cellulose, changes in cellulase activity could not explain the effect. At an extracellular pH of 6.9, the pH gradient (delta pH) across the cell membrane was only 0.07 U. As extracellular pH declined from 6.9 to 5.7, intracellular pH decreased to a smaller extent than extracellular pH and delta pH increased. Below pH 5.7, there was a linear and nearly proportional decrease in intracellular pH. B. succinogenes took up the lipophilic cation tetraphenylphosphonium ion (TPP+) in the presence of cellobiose, and uptake was sensitive to the ionophore valinomycin. As pH was decreased with phosphoric acid, the cells lost TPP+ and electrical potential, delta psi, decreased. From extracellular pH 6.9 to 5.7, the decrease in delta psi was compensated for by an increase in delta pH, and the proton motive force ranged from 152 to 158 mV. At a pH of less than 5.7, there was a large decrease in proton motive force, and this decrease corresponded to the inhibition of cellobiose utilization.
Initial Steps in the Pathway for Bacterial Degradation of Two Tetrameric Lignin Model Compounds
Authors: Jokela Jouni , Pellinen Jukka , Salkinoja-Salonen Mirja
Published: January 2020

We investigated the metabolic route by which a lignin tetramer-degrading mixed bacterial culture degraded two tetrameric lignin model compounds containing β—O—4 and 5—5 biphenyl structures. The α-hydroxyl groups in the propane chain of both phenolic and nonphenolic tetramers were first oxidized symmetrically in two successive steps to give monoketones and diketones. These ketone metabolites were decomposed through C
α
(=O)—C
β
cleavage, forming trimeric carboxyl acids which were further metabolized through another C
α
(=O)—C
β
cleavage. Dehydrodiveratric acid, which resulted from the cleavage of the carbon bonds of the nonphenol tetramer, was demethylated twice. Four metabolites of the phenolic tetramer were purified and identified. All of these were stable compounds in sterile mineral medium, but were readily degraded by lignin tetramer-degrading bacteria along the same pathway as the phenol tetramer. No monoaromatic metabolites accumulated. All metabolites were identified by mass and proton magnetic resonance spectrometry. The metabolic route by which the mixed bacterial culture degraded tetrameric lignin model compounds was different from the route of the main ligninase-catalyzed C
α
—C
β
cleavage by
Phanerochaete chrysosporium.
The glycoprotein toxin of Bacillus thuringiensis subsp. israelensis indicates a lectinlike receptor in the larval mosquito gut
Authors: Muthukumar G , Nickerson K W
Published: January 2020

The mosquito-active protein crystals produced by Bacillus thuringiensis subsp. israelensis contain covalently attached aminosugars which are critical for their larvicidal activity. The 50% lethal concentrations toward Aedes aegypti larvae were increased up to 10-fold by mild periodate treatment, up to 40-fold by forming the protein crystals in the presence of tunicamycin, and up to 7-fold by the presence during the mosquito bioassays of N-acetylglucosamine or its trimer, triacetylchitotriose. Periodate-treated crystals and crystals formed in the presence of tunicamycin had greatly reduced binding capacities for wheat germ agglutinin, an N-acetylglucosamine-specific lectin. These results suggest that the B. thuringiensis subsp. israelensis glycoprotein toxin binds to a lectinlike receptor in the larval mosquito gut. Furthermore, the distinct lectin-binding patterns exhibited by diptera-active versus lepidoptera-active B. thuringiensis crystals suggest that host specificity for the microbial insecticides is determined, in part, by the carbohydrate portion of their glycoprotein crystals.
Complementary Methodologies To Identify Specific
Agrobacterium
Strains
Authors: Bouzar Hacene , Moore Larry W.
Published: January 2020

Serological techniques and restriction enzyme cleavage patterns of total DNA were used to differentiate strains of
Agrobacterium
spp. Forty-five wild-type and plasmid-cured
Agrobacterium
strains were tested by immunodiffusion and immunofluorescence against polyclonal antisera to a crude ribosome preparation from
Agrobacterium
strains K84, U11, B6, A323, NT1, and C58. In immunodiffusion gels, these antisera reacted only with water-phenol extracts of the homologous strain, producing a single, strain-specific precipitin line. In contrast, when the same antisera were used in immunofluorescence staining, cross-reactions occurred with a limited number of heterologous
Agrobacterium
strains. However, the cross-reacting heterologous cells fluoresced generally less brightly than the homologous cells. When the
Eco
RI-digested DNA profiles from the same
Agrobacterium
strains were compared, 34 distinct cleavage patterns were observed. The DNA profiles were the same for all strains sharing a common chromosomal background and correlated with the strain-specific serological reaction. The presence or absence of plasmid DNA did not alter the strain-specific serological reaction or the DNA cleavage patterns. Both the serological reaction and the restriction enzyme digestion of total DNA were complementary to each other. These methods were used successfully to identify
A. radiobacter
K84 strains which were recovered 6 months after being inoculated to young trees in the field.

Images
Adaptation of Aquatic Microbial Communities to Hg
2+
Stress
Authors: Barkay Tamar
Published: January 2020

The mechanism of adaptation to Hg
2+
in four aquatic habitats was studied by correlating microbially mediated Hg
2+
volatilization with the adaptive state of the exposed communities. Community diversity, heterotrophic activity, and Hg
2+
resistance measurements indicated that adaptation of all four communities was stimulated by preexposure to Hg
2+
. In saline water communities, adaptation was associated with rapid volatilization after an initial lag period. This mechanism, however, did not promote adaptation in a freshwater sample, in which Hg
2+
was volatilized slowly, regardless of the resistance level of the microbial community. Distribution of the
mer
operon among representative colonies of the communities was not related to adaptation to Hg
2+
. Thus, although volatilization enabled some microbial communities to sustain their functions in Hg
2+
-stressed environments, it was not mediated by the genes that serve as a model system in molecular studies of bacterial resistance to mercurials.
Increased production of aspartase in Escherichia coli K-12 by use of stabilized aspA recombinant plasmid
Authors: Nishimura N , Komatsubara S , Kisumi M
Published: January 2020

Recombinant plasmid pYT471, which consists of the aspartase gene (aspA) and the multicopy vector pBR322, was lost from cells of Escherichia coli K-12 at high frequencies in medium in which aspartase was abundantly formed due to release from catabolite repression. This plasmid loss was not completely prevented by the selective pressure of antibiotic addition. To increase the stability of the aspA plasmid, pNK101 (pBR322::aspA-par) was constructed by using the partition locus (par) derived from the low-copy vector pSC101. In E. coli K-12 cells, pNK101 was lost at a frequency as low as 0.4% per cell generation in nonselective medium, whereas pYT471 was lost at a frequency as high as 8.5%. Cells harboring this stable plasmid produced ca. 30-fold more aspartase than did cells harboring the unstable plasmid after 30 cell generations. Thus, we could increase aspartase production by stabilizing the aspA recombinant plasmid.
A Phosphate-Bond-Driven Dipeptide Transport System in
Streptococcus cremoris
Is Regulated by the Internal pH
Authors: van Boven A. , Konings W. N.
Published: January 2020

The uptake of amino acids and peptides by
Streptococcus cremoris
is mediated by different highly specific transport systems. The leucine transport system has a high affinity only for leucine, isoleucine, and valine and no affinity for leucyl-peptides. The transport system for leucyl-leucine is strongly inhibited by several dipeptides with hydrophobic, neutral, N-terminal amino acids but not by leucine. The leucyl-leucine transport system has a high affinity for dipeptides containing β-methyl groups in the side chain; the C terminus of the dipeptide affects the affinity to a much lower extent. Leucyl-leucine transport in whole cells was studied as a function of the internal pH at different external pH values in the presence and absence of nigericin. The internal pH was shown to be an important controlling factor in leucyl-leucine uptake, but the ΔpH was not involved as a driving force. At increasing external pH values, the affinity of the transport system for leucyl-leucine decreased. Uptake of leucyl-leucine was also studied in the presence of arsenate, which inhibited ATP synthesis by substrate-level phosphorylation. The rate of leucyl-leucine transport appeared to be dependent on the intracellular ATP concentrations. These results indicate that the energy for the leucyl-leucine transport is directly supplied by ATP.
Inactivation of Legionella pneumophila by hypochlorite and an organic chloramine
Authors: Swango L J , Wilt G R , Killen A D , Williams D E , Worley S D
Published: January 2020

The susceptibility of a strain of Legionella pneumophila to disinfection by an organic halamine, free chlorine, and a mixture of the organic halamine and free chlorine was assessed. The organic halamine was found to have superior stability in solution and to exhibit adequate disinfectant potential over a period of 1 month of repeated reinoculations of fresh bacteria. The combined halamine exhibited great potential for use in maintaining closed-cycle cooling water systems free of L. pneumophila.
Expression Vector for
Zymomonas mobilis
Authors: Conway T. , Byun M. O.-K. , Ingram L. O.
Published: January 2020

This study describes the construction of several useful cloning vectors which can be conjugated from
Escherichia coli
into
Zymomonas mobilis
at high frequency, approaching 10
−2
per donor or recipient. These vectors contain a broad-host-range replicon and
mob
site from RSF1010, a chloramphenicol acyltransferase gene under the control of an enteric consensus promoter, and a second
mob
site (originally derived from RP4). The addition of this second
mob
site appears to be responsible for a 2-order-of-magnitude increase in the efficiency of transfer into
Z. mobilis.
Such vectors may be useful for other gram-negative bacteria in which conjugation efficiencies are low. These vectors are stably maintained in
Z. mobilis
with no detectable loss of plasmid after 50 generations in the absence of selective pressure. One of these, pLOI193, contains the tetracycline gene from pBR322 and associated cloning sites for insertional inactivation. Another, pLOI204, contains a
Z. mobilis
promoter immediately upstream from a
Bam
HI site which can be used for cloning. This promoter has been shown to efficiently drive the expression of beta-galactosidase in both
Z. mobilis
and
E. coli.
This promoter fragment from
Z. mobilis
has been sequenced, and the site for transcriptional initiation in
E. coli
and
Z. mobilis
has been identified.
Production of Microbial Biomass Protein from Potato Processing Wastes by
Cephalosporium eichhorniae
Authors: Stevens Coleen A. , Gregory Kenneth F.
Published: January 2020

The use of
Cephalosporium eichhorniae
152 (ATCC 38255) (reclassified as
Acremonium alabamense
; see Addendum in Proof), a thermophilic, acidophilic, amylolytic fungus, for the conversion of potato processing wastes into microbial protein for use as animal feed was studied. The fungus was not inhibited by α-solanine or β-2-chaconine, antimicrobial compounds in potatoes, or by morpholine or cyclohexylamine (additives to steam used in the peeling process) at levels likely to be encountered in this substrate. Mixed effluent from holding tanks at a potato-processing plant contained about 10
9
bacteria per ml and inhibited fungal growth. The fungus grew well on fresh potato wastes containing up to 5% total carbohydrate and utilized both starch and protein at 45°C and pH 3.75. On potato homogenate medium containing 2% carbohydrate (about 14% fresh potato) supplemented with monoammonium phosphate (0.506 g/liter) and ferric iron (0.1 g/liter), with pH control (at 3.75) and additional nitrogen supplied by the automatic addition of ammonium hydroxide, typical yields were 0.61 g (dry weight) of product and 0.3 g of crude protein per g of carbohydrate supplied. An aerobic, spore-forming bacterium, related to
Bacillus brevis
, commonly contaminated nonsterilized batch cultures but was destroyed by heating for 15 min at 100°C.
Lactobacilli as effectors of host functions: no influence on the activities of enzymes in enterocytes of mice
Authors: Whitt D D , Savage D C
Published: January 2020

Preparations of lactobacilli are often used as dietary supplements to improve the growth and efficiency in utilizing food of animals of commercial value. We tested in an experimental model whether the effects of lactobacilli on growth of and food utilization by animals may be due to alteration of the activities of absorptive enzymes in the small bowel. Germfree mice housed in isolators under tightly controlled conditions were monoassociated with one of four strains of indigenous Lactobacillus spp. From 1 to 5 weeks later, the activity of alkaline phosphatase was assayed in homogenates of segments of the upper small intestines of the associated animals and of matched germfree controls. The specific activity of the enzyme was the same in the mice in the two groups. In other experiments, epithelial cells were isolated from the upper small intestines of mice associated with eight Lactobacillus strains (octa-associated) and from those of matched germfree mice and assayed for alkaline phosphatase, phosphodiesterase, and thymidine kinase activities. The epithelial cells were harvested sequentially from the tips of the villi toward the crypts of Lieberkühn of the intestines. In all preparations, mice of both types yielded an equivalent mass (wet weight) of cells. The protein content of the cells reflected the mass. The activities of the microvillous membrane enzymes alkaline phosphatase and phosphodiesterase and the cytosol enzyme thymidine kinase were the same whether or not the animals contained the bacteria. Therefore, any effects on animal growth and food utilization observed when lactobacilli are used as dietary supplements may not be due to a direct alteration by the bacteria of the absorptive enzymes of the host animal.(ABSTRACT TRUNCATED AT 250 WORDS)
Rhizobium
Population Genetics: Enzyme Polymorphism in
Rhizobium leguminosarum
from Plants and Soil in a Pea Crop
Authors: Young J. P. W. , Demetriou L. , Apte R. G.
Published: January 2020

A population of
Rhizobium leguminosarum
biovar
viceae
symbiotic on the roots of a commercial pea (
Pisum sativum
cv. Maro) crop was sampled by extracting a total of 249 isolates from root nodules on nine plants. Another 104 isolates were obtained by using soil from the same site to inoculate test plants, and a further 86 isolates were similarly obtained from soil 20 m distant within the crop. Each isolate was characterized for mobility variants of the enzymes glucose-6-phosphate dehydrogenase, superoxide dismutase, and β-galactosidase by polyacrylamide gel electrophoresis. All three enzymes were polymorphic, and there was a strong disequilibrium among them. Of the 15 observed combinations of alleles (electrophoretic types [ETs]), 12 were indistinguishable from those previously described for isolates from a site 25 km distant. ET frequencies were significantly different among isolates from nodules on primary roots as opposed to lateral roots. The population on each individual plant was very diverse, but ET frequencies were similar from plant to plant. The ETs nodulating the primary roots were almost, although not perfectly, mixed, since the incidence of the same ETs in adjacent nodules was only about twice that expected by chance. The two samples derived from soil had the same ET frequencies but were significantly different from the field nodule sample, although the level of diversity was similar and there were no new ETs.
Toxic Trypsin Digest Fragment from the
Bacillus thuringiensis
Parasporal Protein
Authors: Aronson John N. , Arvidson Harold C.
Published: January 2020

Enzymatic digestion in vitro of the
Bacillus thuringiensis
protoxin presumably releases and activates the toxin in a manner analogous to that which occurs when a
B. thuringiensis
sporulated fermentation preparation passes through the midgut of a lepidopteran larva. Therefore, a sporulated culture of
B. thuringiensis
subsp.
kurstaki
(serotype 3a3b) HD-263 was treated with trypsin to release an activated toxin soluble in bicarbonate buffer. A 63-kilodalton protein, toxic to cabbage looper larvae (
Trichoplusia ni
) and to lepidopteran cells in culture, was purified to homogeneity from this trypsin digest. The larvicide, a glycoprotein containing 5% carbohydrate (wt/wt), was purified from the soluble
B. thuringiensis
trypsin digest by using ammonium sulfate precipitation, anion-exchange chromatography, and hydrophobic-interaction chromatography. Its amino acid composition was high in nonpolar residues and unusually low in lysine and histidine. The isoelectric point was 6.5, and the amino acid on the N terminus was identified as isoleucine. The toxin was only slightly soluble in aqueous buffers unless the chaotropic agent potassium thiocyanate was added. Partial characterization of the toxin indicated that it corresponds well with reported sequences deduced from cloned genes.
Transport of lactate and other short-chain monocarboxylates in the yeast Saccharomyces cerevisiae
Authors: C�ssio F , Le�o C , van Uden N
Published: January 2020

Saccharomyces cerevisiae IGC4072 grown in lactic acid medium transported lactate by an accumulative electroneutral proton-lactate symport with a proton-lactate stoichiometry of 1:1. The accumulation ratio measured with propionate increased with decreasing pH from ca. 24-fold at pH 6.0 to ca. 1,400-fold at pH 3.0. The symport accepted the following monocarboxylates (Km values at 25 degrees C and pH 5.5): D-lactate (0.13 mM), L-lactate (0.13 mM), pyruvate (0.34 mM), propionate (0.09 mM), and acetate (0.05 mM), whereas apparently a different proton symport accepted formate (0.13 mM). The lactate system was inducible and was subject to glucose repression. Undissociated lactic acid entered the cells by simple diffusion. The permeability of the plasma membrane for undissociated lactic acid increased exponentially with pH, and the diffusion constant increased 40-fold when the pH was increased from 3.0 to 6.0.
Identification of major common extracellular proteins secreted by Aeromonas salmonicida strains isolated from diseased fish
Authors: Fyfe L , Coleman G , Munro A L
Published: January 2020

Ten different strains of Aeromonas salmonicida that were isolated from diseased fish were grown under identical conditions (24 h at 25 degree C) in 3% (wt/vol) tryptone soya broth medium supplemented with vitamins and inorganic ions. In each case the extracellular proteins that were formed were compared by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and it was found that there were two significant common components, one with a molecular weight of 70,000 and the other with a weight of 56,000. Application of enzyme purification techniques to the supernatant fraction proteins of a culture of one of the strains resulted in the isolation of a 70-kilodalton (kDa) component, which was found to be a serine protease, and a 56-kDa component, which was hemolytic to trout erythrocytes. Rocket immunoelectrophoresis with rabbit antibodies to the isolated protease and hemolysin showed the same antigenic components in the supernatant fractions of all the cultures. These activities were assayed, and protease activity was found to vary by a factor of three, from 59 to 195 U/ml, while the range of hemolytic activity was over a narrow band, from 28 to 43 U/ml. There was an inconsistency between the immunoelectrophoretic and direct assay data in only one case. This indicated the presence of additional hemolytic activity, in addition to the 56-kDa component. The detection of large amounts of the same protease and hemolysin, two potent degradative activities, in a random series of strains of A. salmonicida suggests that they may be obligatory virulence factors in the development of furunculosis.
Cross-Reaction of Predominant Nitrogen-Fixing Bacteria with Enveloped, Round Bodies in the Root Interior of Kallar Grass
Authors: Reinhold Barbara , Hurek Thomas , Fendrik Istvan
Published: January 2020

Diazotrophic rods occurring in high numbers (about 10
8
rods per g [dry weight] of root) in the root interior of Kallar grass were localized by indirect immunofluorescence in cross sections of the same roots. Specifically stained round bodies which were apparently covered by a nonantigenic envelope were found in the aerenchymatic tissue.
Isolation of a Cellodextrinase from
Bacteroides succinogenes
Authors: Huang Li , Forsberg Cecil W.
Published: January 2020

An enzyme which released the cellobiose group from
p
-nitrophenyl cellobioside was isolated from the periplasmic space of
Bacteroides succinogenes
grown on Avicel crystalline cellulose in a continuous cultivation system and separated from endoglucanases by column chromatography. The molecular weight of the enzyme was approximately 40,000, as estimated by gel filtration. The enzyme has an isoelectric point of 4.9. The enzyme exhibited low hydrolytic activity on acid-swollen cellulose and practically no activity on carboxymethyl cellulose, Avicel cellulose, and cellobiose, but it hydrolyzed
p
-nitrophenyl lactoside and released cellobiose from cellotriose and from higher cello-oligosaccharides. These data demonstrate that the enzyme is a cellodextrinase with an exotype of function.
Isolation and characterization of an s-ethyl-N,N-dipropylthiocarbamate-degrading Arthrobacter strain and evidence for plasmid-associated s-ethyl-N,N-dipropylthiocarbamate degradation
Authors: Tam A C , Behki R M , Khan S U
Published: January 2020

Arthrobacter sp. strain TE1 isolated from s-ethyl-N,N-dipropylthiocarbamate (EPTC)-exposed soil degraded this herbicide effectively and could grow on EPTC as the sole carbon source. TE1 harboured four plasmids of 65.5, 60, 50.5, and 2.5 megadaltons. Spontaneous mutants unable to degrade EPTC arose at a high frequency, and this was further increased by treatment of the culture with acridine orange or incubation at high temperature. All EPTC degradation-deficient (E-) mutants lacked the 50.5-megadalton plasmid. This plasmid could be transferred from TE1 to E- mutants by conjugation, resulting in the restoration of EPTC-degrading ability to the mutants.
Environmental Factors Influencing Numbers of
Rhizobium leguminosarum
biovar
trifolii
and Its Bacteriophages in Two Field Soils
Authors: Lawson Kerrie A. , Barnet Yvonne M. , McGilchrist Clyde A.
Published: January 2020

Fluctuations in numbers of
Rhizobium leguminosarum
biovar
trifolii
and its bacteriophages in two fields with different soil types were followed during a 17-month period in 1981 and 1982. Mean levels of both phage and rhizobia varied significantly (
P
< 0.05) on different occasions, with rhizobial levels varying from 1.6 × 10
2
to 2.0 × 10
4
cell per g of soil and phage from 0 to 1.7 × 10
4
PFU/g of soil. Multivariate regression analysis showed rhizobial levels to be significantly and positively related to vegetation height and solar radiation, but not to mean temperature, precipitation, soil matric potential, or soil type. Rhizobiophage concentrations were significantly and positively related to soil matric potential and vegetation height. They were reduced in the silty clay loam soil, although the presence of 34% clay did not prevent phage multiplication and the occurrence of high phage levels.
Influence of Alginate on Attachment of
Vibrio
spp. to Stainless Steel Surfaces in Seawater
Authors: Gordon Andrew S.
Published: January 2020

The influence of alginate on the attachment of
Vibrio alginolyticus
and
Vibrio pelagius
biovar II to stainless steel was investigated. When the bacteria were in stationary phase, alginate decreased the number of attached bacteria in the case of each
Vibrio
sp. In contrast, when
V. pelagius
biovar II was grown on alginate and harvested in log phase, attachment was increased. This effect may be due to nutrient availability at the surface or to receptors on the bacterial surface which interact with alginate adsorbed to the metal.
Separation of
Syntrophomonas wolfei
from
Methanospirillum hungatii
in Syntrophic Cocultures by Using Percoll Gradients
Authors: Beaty P. Shawn , Wofford Neil Q. , McInerney Michael J.
Published: January 2020

Percoll gradient centrifugation effectively separated
Syntrophomonas wolfei
cells from
Methanospirillum hungatii
cells, resulting in a 70- to 80-fold enrichment of
S. wolfei
cells relative to
M. hungatii
cells. The separated
S. wolfei
cells were viable. Gram quantities of cellular protein which was enzymatically active and had low levels of contamination by the methanogenic cofactor, factor
420
, were obtained.
Direct Colony Thin-Layer Chromatography and Rapid Characterization of
Serratia marcescens
Mutants Defective in Production of Wetting Agents
Authors: Matsuyama Tohey , Sogawa Masakazu , Yano Ikuya
Published: January 2020

A bacterial mass (ca. 1 mg) was placed directly on a thin-layer chromatography plate and developed shortly in chloroform-methanol (2:1, vol/vol). After being dried, the bacterial mass was developed in chloroform-methanol-5 M ammonia (80:25:4, vol/vol). The obtained chromatogram indicated the characteristic lipid compositions of the bacteria. So, it became possible to examine bacterial colonies at once for the identification of mutants defective in the production of specific lipids.
Evaluation of the multitest medium for rapid presumptive identification of Vibrio cholerae from environmental sources
Authors: Nair G B , Misra S , Bhadra R K , Pal S C
Published: January 2020

The multitest V. cholerae medium (VC medium) for rapid presumptive identification of Vibrio cholerae was evaluated. On the basis of reactions in the VC medium, 379 strains recovered during a yearlong ecological study in Calcutta were presumptively identified as V. cholerae. Further phenotypic characterization of these strains revealed that the reactions of 371 (97.9%) isolates were consistent with that of V. cholerae. False-positive reactions were exhibited by eight (2.1%) strains, three of which were identified as Vibrio fluvialis biotype 1. By slightly varying the basic formulation of the VC medium, we could eliminate some false-positive reactions. On the basis of the present evaluation, we recommend the routine use of the VC medium.
Plasmid-Determined Systems for Restriction and Modification Activity and Abortive Infection in
Streptococcus cremoris
Authors: Gautier Michel , Chopin Marie-Christine
Published: January 2020

Streptococcus cremoris
strain IL964 possessed a restriction and modification (R/M) activity which resulted in a bacteriophage efficiency of plating of 5 × 10
−6
. Phage sensitivity of protoplast-induced plasmid-cured derivatives indicated that two plasmids called pIL103 (5.7 kilobases) and pIL107 (15.2 kilobases) were each coding for one R/M system. Plasmid pIL103-encoded R/M was ascertained by transfer into the plasmid-free, R
−
/M
−
strain IL1403 of
S. lactis
, using protoplast cotransformation. This procedure failed for pIL107 because of some degree of incompatibility between pIL107 and the indicator plasmid pHV1301 used in cotransformation experiments. We also observed that plasmid pIL105 (8.7 kilobases) which showed no incidence on phage sensitivity in the parental strain IL964, mediated abortive infection in strain IL1403. In 97% of the infected cells, the phage infection was abortive, while in the remaining 3% phages were produced with a decreased burst size (50 instead of 180).
Maintenance and stability of introduced genotypes in groundwater aquifer material
Authors: Jain R K , Sayler G S , Wilson J T , Houston L , Pacia D
Published: January 2020

Three indigenous groundwater bacterial strains and Pseudomonas putida harboring plasmids TOL (pWWO) and RK2 were introduced into experimentally contaminated groundwater aquifer microcosms. Maintenance of the introduced genotypes was measured over time by colony hybridization with gene probes of various specificity. On the basis of the results of colony hybridization quantitation of the introduced organisms and genes, all introduced genotypes were stably maintained at approximately 10(5) positive hybrid colonies g-1 of aquifer microcosm material throughout an 8-week incubation period. Concomitant removal of the environmental contaminants, viz., toluene, chlorobenzene, and styrene, in both natural (uninoculated) and inoculated aquifer microcosms was also demonstrated. The results indicate that introduced catabolic plasmids, as well as indigenous organisms, can be stably maintained in groundwater aquifer material without specific selective pressure for the introduced genotypes. These results have positive implications for in situ treatment and biodegradation in contaminated aerobic groundwater aquifers.
Annual Bacterioplankton Biomasses and Productivities in a Temperate West Coast Canadian Fjord
Authors: Albright L. J. , McCrae S. K.
Published: January 2020

Bacterioplankton numbers, biomasses, and productivities, as well as chlorophyll
a
concentrations and phytoplankton productivities, were assayed from 1 March 1984 to 12 August 1985 through a 250-m-deep seawater column in Howe Sound, a temperate fjord-sound on the southern coast of British Columbia, Canada. Primary production during this 18-month period was 845 g of C m
−2
. Bacterial production was assayed over this same period as 193 g of C m
−2
(thymidine incorporation) and 77 g of C m
−2
(frequency of dividing cells). Bacterial productivities per cubic meter were usually greater in the euphotic zone than in deeper aphotic water, but when integrated through the water column, approximately half of the bacterial production occurred in the deeper aphotic portion. Bacterial production occurred throughout the year, although at reduced rates in late fall and early winter; primary production almost ceased during late fall and early winter. Because of this heterotrophic bacterioplankton production was a very large portion of the microbial (bacterial plus phyto-plankton) production at this time. In mid-summer bacterial production was a small proportion of the microbial production. Because of this asynchrony in peaks and troughs of bacterial and phytoplankton production through the year, data comparison is best done over an annual cycle. On this basis the bacterial production in the Howe Sound water column was between 23 and 9% of the phytoplankton production when a bacterial C to biovolume ratio of 0.107 pg of C μm
−3
was assumed; the corresponding values were 64 and 29% when a ratio of 0.300 pg of bacterial C μm
−3
was assumed.