bluuebunny/crossref_metadata_2025 huggingface dataset:
Archaeoglobus fulgidus
Isolated from Hot North Sea Oil Field Waters
Authors: Beeder Janiche , Nilsen Roald Kåre , Rosnes Jan Thomas , Torsvik Terje , Lien Torleiv
Published: January 2020

A hyperthermophilic sulfate reducer, strain 7324, was isolated from hot (75°C) oil field waters from an oil production platform in the Norwegian sector of the North Sea. It was enriched on a complex medium and isolated on lactate with sulfate. The cells were nonmotile, irregular coccoid to disc shaped, and 0.3 to 1.0 μm wide. The temperature for growth was between 60 and 85°C with an optimum of 76°C. Lactate, pyruvate, and valerate plus H
2
were utilized as carbon and energy sources with sulfate as electron acceptor. Lactate was completely oxidized to CO
2
. The cells contained an active carbon monoxide dehydrogenase but no 2-oxoglutarate dehydrogenase activity, indicating that lactate was oxidized to CO
2
via the acetyl coenzyme A/carbon monoxide dehydrogenase pathway. The cells produced small amounts of methane simultaneously with sulfate reduction. F
420
was detected in the cells which showed a blue-green fluorescence at 420 nm. On the basis of morphological, physiological, and serological features, the isolate was classified as an
Archaeoglobus
sp. Strain 7324 showed 100% DNA-DNA homology with
A. fulgidus
Z, indicating that it belongs to the species
A. fulgidus. Archaeoglobus
sp. has been selectively enriched and immunomagnetically captured from oil field waters from three different platforms in the North Sea. Our results show that strain 7324 may grow in oil reservoirs at 70 to 85°C and contribute to hydrogen sulfide formation in this environment.
Galactose Expulsion during Lactose Metabolism in
Lactococcus lactis
subsp.
cremoris
FD1 Due to Dephosphorylation of Intracellular Galactose 6-Phosphate
Authors: Benthin Stig , Nielsen Jens , Villadsen John
Published: January 2020

In
Lactococcus lactis
subsp.
cremoris
FD1, galactose and lactose are both transported and phosphorylated by phosphotransferase systems. Lactose 6-phosphate (lactose-6P) is hydrolyzed intracellularly to galactose-6P and glucose. Glucose enters glycolysis as glucose-6P, whereas galactose-6P is metabolized via the tagatose-6P pathway and enters glycolysis at the tagatose diphosphate and fructose diphosphate pool. Galactose would therefore be a gluconeogenic sugar in
L. lactis
subsp.
cremoris
FD1, but since fructose 1,6-diphosphatase is not present in this strain, galactose cannot serve as an essential biomass precursor (glucose-6P or fructose-6P) but only as an energy (ATP) source. Analysis of the growth energetics shows that transition from N limitation to limitation by glucose-6P or fructose-6P gives rise to a very high growth-related ATP consumption (152 mmol of ATP per g of biomass) compared with the value in cultures which are not limited by glucose-6P or fructose-6P (15 to 50 mmol of ATP per g of biomass). During lactose metabolism, the galactose flux through the tagatose-6P pathway (
r
max
= 1.2 h
-1
) is lower than the glucose flux through glycolysis (
r
max
= 1.5 h
-1
) and intracellular galactose-6P is dephosphorylated; this is followed by expulsion of galactose. Expulsion of a metabolizable sugar has not been reported previously, and the specific rate of galactose expulsion is up to 0.61 g of galactose g of biomass
-1
h
-1
depending on the lactose flux and the metabolic state of the bacteria. Galactose excreted during batch fermentation on lactose is reabsorbed and metabolized when lactose is depleted from the medium. In vitro incubation of galactose-6P (50 mM) and permeabilized cells (8 g/liter) gives a supernatant containing free galactose (50 mM) but no P
i
(less than 0.5 mM). No organic compound except the liberated galactose is present in sufficient concentration to bind the phosphate. Phosphate is quantitatively recovered in the supernatant as P
i
by hydrolysis with alkaline phosphatase (EC 3.1.3.1), whereas inorganic pyrophosphatase (EC 3.6.1.1) cannot hydrolyze the compound. The results indicate that the unknown phosphate-containing compound might be polyphosphate.
Comparison of ribosomal DNA length and restriction site polymorphisms in Gremmeniella and Ascocalyx isolates
Authors: Bernier L , Hamelin R C , Ouellette G B
Published: January 2020

The small subunit (SSU) and the internal transcribed spacer (ITS) of nuclear ribosomal DNA genes from 27 specimens of the fungal genera Gremmeniella and Ascocalyx were amplified by PCR. Length polymorphisms were observed in the SSU and allowed the differentiation of four groups among the isolates tested: (i) Ascocalyx abietis; (ii) Gremmeniella isolates from Picea spp.; (iii) Gremmeniella isolates from Abies balsamea; and (iv) Gremmeniella isolates from Abies sacchalinensis, Larix spp., and Pinus spp. The amplified ITS was the same length for all Gremmeniella specimens and was 60 bp longer in A. abietis. Phylogenetic analysis of length polymorphisms and of 24 restriction sites in the SSU and ITS showed that Gremmeniella isolates were more related to each other than to the Ascocalyx isolate. Furthermore, seven groups were evident within the genus Gremmeniella. Our results confirm that Gremmeniella and Ascocalyx should be kept as different taxa and suggest that the taxonomy of the former could be revised to consider isolates from Abies balsamea and from Picea spp. to be two different varieties while incorporating Gremmeniella laricina into G. abietina, as a new variety.
Nutrient Effect on the Biological Leaching of a Black-Schist Ore
Authors: Niemelä Seppo I. , Riekkola-Vanhanen Marja , Sivelä Carita , Viguera Felipe , Tuovinen Olli H.
Published: January 2020

The purpose of the study was to examine the influence of inorganic N (NH
4
+
, NO
3
-
) and phosphate on the biological oxidation of a sulfidic black-schist ore which contained pyrrhotite as the main iron sulfide. Iron was initially solubilized as Fe
2+
from the ore and subsequently oxidized to Fe
3+
in shake flask experiments. Under these experimental conditions, iron dissolution from pyrrhotite was mainly a chemical reaction, with some enhancement by bacteria, whereas the subsequent Fe
2+
oxidation was bacterially mediated, with negligible contribution from chemical oxidation. Phosphate amendment did not enhance Fe
2+
oxidation. Chemical analysis of leach solutions with no exogenous phosphate revealed that phosphate was solubilized from the black-schist ore. Ammonium amendment (6 mM) enhanced Fe
2+
oxidation, whereas the addition of nitrate (6 and 12 mM) had a negative effect. An increase in the temperature from 30 to 35°C slightly enhanced Fe
2+
oxidation, but the effect was statistically not significant. The precipitation of potassium jarosite was indicative of Fe
2+
oxidation and was absent in nitrate-inhibited cultures because of the lack of Fe
2+
oxidation. The black-schist ore also contained phlogopite, which was altered to vermiculite in iron-oxidizing cultures.
Role of Anaerobic Ciliates in Planktonic Food Webs: Abundance, Feeding, and Impact on Bacteria in the Field
Authors: Massana Ramon , Pedrós-Alió Carlos
Published: January 2020

We studied the dynamics of two populations of anaerobic ciliates,
Plagiopyla
sp. and
Metopus
sp., and of their potential prey, heterotrophic and phototrophic purple bacteria, in Lake Cisó throughout a 1-year cycle. The abundance of both ciliates was very low (less than 2 individuals per ml). During mixing,
Plagiopyla
ciliates exhibited high clearance rates (about 100 nl ciliate
-1
h
-1
), its integrated abundance increased with a net doubling time of 47 days, and its potential doubling times, as calculated from the number of bacteria consumed, ranged between 5 and 8 days. During stratification, the activity of
Plagiopyla
ciliates was reduced and the population decreased; this was related to the higher amounts of sulfide present. The impact of predation by the
Plagiopyla
population on bacterioplankton was found to be insignificant, less than 0.1% of bacterial biomass consumed per day. Thus, anaerobic ciliates cannot control the bacterioplankton in Lake Cisó because of both the low abundance over the period studied and the low feeding rates during certain periods. A review of available field studies suggests that this conclusion can be extrapolated to most other anoxic systems.
Selective enumeration of Fusobacterium necrophorum from the bovine rumen
Authors: Tan Z L , Nagaraja T G , Chengappa M M
Published: January 2020

A culture medium containing lactate as the sole energy source and antibiotics (bacitracin, gentamicin, and streptomycin) was used for selection and enumeration of Fusobacterium necrophorum from bovine ruminal contents. F. necrophorum growth was determined by indole production, and enumeration was performed by the most-probable-number technique. The number of F. necrophorum cells in cattle fed a 100% forage diet was 7 x 10(5)/g of ruminal contents. The number increased (P < 0.05) 10-fold after the diet was changed to 85% corn grain.
Use of homologous expression-secretion signals and vector-free stable chromosomal integration in engineering of Lactobacillus plantarum for alpha-amylase and levanase expression
Authors: Hols P , Ferain T , Garmyn D , Bernard N , Delcour J
Published: January 2020

The genuine alpha-amylase gene from Bacillus licheniformis (amyL) is not expressed in Lactobacillus plantarum, but replacement of the amyL promoter by a strong L. plantarum promoter leads to efficient expression of the gene and secretion of more than 90% of the alpha-amylase into the culture supernatant. A series of L. plantarum genetic cassettes (transcription and translation with or without secretion) were cloned by translation fusion of random DNA fragments to the silent amyL coding frame in the pGIP212 probe vector (P. Hols, A. Baulard, D. Garmyn, B. Delplace, S. Hogan, and J. Delcour, Gene 118:21-30, 1992). Five different cassettes were sequenced and found to harbor genetic signals similar to those of other gram-positive bacteria. The functions of the cloned cassettes and the cassettes isolated previously from Enterococcus faecalis were compared in E. faecalis and L. plantarum, respectively. All signals were well recognized in L. plantarum, but cassettes isolated from L. plantarum led to a low level of amylase production in E. faecalis, suggesting that the L. plantarum signals are more species specific. Six transcriptional or translational fusions were constructed to express the Bacillus subtilis levanase gene (sacC) in L. plantarum. All of these constructions were capable of inducing levanase production and secretion in the culture supernatant, and, furthermore, L. plantarum strains harboring the most efficient fusions could grow in MRS medium containing inulin as the major carbon source. Finally, a two-step chromosomal integration procedure was used to achieve efficient stabilization of an amylase construction without any residual resistance marker or vector sequence.
PCR and restriction fragment length polymorphism of a pel gene as a tool to identify Erwinia carotovora in relation to potato diseases
Authors: Darrasse A , Priou S , Kotoujansky A , Bertheau Y
Published: January 2020

Using a sequenced pectate lyase-encoding gene (pel gene), we developed a PCR test for Erwinia carotovora. A set of primers allowed the amplification of a 434-bp fragment in E. carotovora strains. Among the 89 E. carotovora strains tested, only the Erwinia carotovora subsp. betavasculorum strains were not detected. A restriction fragment length polymorphism (RFLP) study was undertaken on the amplified fragment with seven endonucleases. The Sau3AI digestion pattern specifically identified the Erwinia carotovora subsp. atroseptica strains, and the whole set of data identified the Erwinia carotovora subsp. wasabiae strains. However, Erwinia carotovora subsp. carotovora and Erwinia carotovora subsp. odorifera could not be separated. Phenetic and phylogenic analyses of RFLP results showed E. carotovora subsp. atroseptica as a homogeneous group while E. carotovora subsp. carotovora and E. carotovora subsp. odorifera strains exhibited a genetic diversity that may result from a nonmonophyletic origin. The use of RFLP on amplified fragments in epidemiology and for diagnosis is discussed.
Aspergillus nidulans verA is required for production of the mycotoxin sterigmatocystin
Authors: Keller N P , Kantz N J , Adams T H
Published: January 2020

Aspergillus nidulans produces the carcinogenic mycotoxin sterigmatocystin (ST), the next-to-last precursor in the aflatoxin (AF) biosynthetic pathway found in the closely related fungi Aspergillus flavus and Aspergillus parasiticus. We identified and characterized an A. nidulans gene, verA, that is required for converting the AF precursor versicolorin A to ST. verA is closely related to several polyketide biosynthetic genes involved in polyketide production in Streptomyces spp. and exhibits extended sequence similarity to A. parasiticus ver-1, a gene proposed to encode an enzyme involved in converting versicolorin A to ST. By performing a sequence analysis of the region 3' to verA, we identified two additional open reading frames, designated ORF1 and ORF2. ORF2 is closely related to a number of cytochrome P-450 monooxygenases, while ORF1 shares identity with the gamma subunit of translation elongation factor 1. Given that several steps in the ST-AF pathway may require monooxygenase activity and that AF biosynthetic genes are clustered in A. flavus and A. parasiticus, we suggest that verA may be part of a cluster of genes required for ST biosynthesis. We disrupted the verA coding region by inserting the A. nidulans argB gene into the center of the coding region and transformed an A. nidulans argB2 mutant to arginine prototrophy. Seven transformants that produced DNA patterns indicative of a verA disruption event were grown under ST-inducing conditions, and all of the transformants produced versicolorin A but negligible amounts of ST (200-fold to almost 1,000-fold less than the wild type), confirming the hypothesis that verA encodes an enzyme necessary for converting versicolorin A to ST.
Optical biosensor for environmental on-line monitoring of naphthalene and salicylate bioavailability with an immobilized bioluminescent catabolic reporter bacterium
Authors: Heitzer A , Malachowsky K , Thonnard J E , Bienkowski P R , White D C , Sayler G S
Published: January 2020

An optical whole-cell biosensor based on a genetically engineered bioluminescent catabolic reporter bacterium was developed for continuous on-line monitoring of naphthalene and salicylate bioavailability and microbial catabolic activity potential in waste streams. The bioluminescent reporter bacterium, Pseudomonas fluorescens HK44, carries a transcriptional nahG-luxCDABE fusion for naphthalene and salicylate catabolism. Exposure to either compound resulted in inducible bioluminescence. The reporter culture was immobilized onto the surface of an optical light guide by using strontium alginate. This biosensor probe was then inserted into a measurement cell which simultaneously received the waste stream solution and a maintenance medium. Exposure under defined conditions to both naphthalene and salicylate resulted in a rapid increase in bioluminescence. The magnitude of the response and the response time were concentration dependent. Good reproducibility of the response was observed during repetitive perturbations with either naphthalene or salicylate. Exposure to other compounds, such as glucose and complex nutrient medium or toluene, resulted in either minor bioluminescence increases after significantly longer response times compared with naphthalene or no response, respectively. The environmental utility of the biosensor was tested by using real pollutant mixtures. A specific bioluminescence response was obtained after exposure to either an aqueous solution saturated with JP-4 jet fuel or an aqueous leachate from a manufactured-gas plant soil, since naphthalene was present in both pollutant mixtures.
Role of Neutral Metabolites in Microbial Conversion of 3β-Acetoxy-19-Hydroxycholest-5-Ene into Estrone
Authors: Madyastha K. M. , Shankar V. N.
Published: January 2020

Biotransformation of 3β-acetoxy-19-hydroxycholest-5-ene (19-HCA, 6 g) by
Moraxella
sp. was studied. Estrone (712 mg) was the major metabolite formed. Minor metabolites identified were 5α-androst-1-en-19-ol-3,17-dione (33 mg), androst-4-en-19-ol-3,17-dione (58 mg), androst-4-en-9α,19-diol-3,17-dione (12 mg), and androstan-19-ol-3,17-dione (1 mg). Acidic metabolites were not formed. Time course experiments on the fermentation of 19-HCA indicated that androst-4-en-19-ol-3,17-dione was the major metabolite formed during the early stages of incubation. However, with continuing fermentation its level dropped, with a concomitant increase in estrone. Fermentation of 19-HCA in the presence of specific inhibitors or performing the fermentation for a shorter period (48 h) did not result in the formation of acidic metabolites. Resting-cell experiments carried out with 19-HCA (200 mg) in the presence of α,α′-bipyridyl led to the isolation of three additional metabolites, viz., cholestan-19-ol-3-one (2 mg), cholest-4-en-19-ol-3-one (10 mg), and cholest-5-en-3β,19-diol (12 mg). Similar results were also obtained when
n
-propanol was used instead of α,α′-bipyridyl. Resting cells grown on 19-HCA readily converted both 5α-androst-1-en-19-ol-3,17-dione and androst-4-en-19-ol-3,17-dione into estrone. Partially purified 1,2-dehydrogenase from steroid-induced
Moraxella
cells transformed androst-4-en-19-ol-3,17-dione into estrone and formaldehyde in the presence of phenazine methosulfate, an artificial electron acceptor. These results suggest that the degradation of the hydrocarbon side chain of 19-HCA does not proceed via C
22
phenolic acid intermediates and complete removal of the C
17
side chain takes place prior to the aromatization of the A ring in estrone. The mode of degradation of the sterol side chain appears to be through the fission of the C
17
-C
20
bond. On the basis of these observations, a new pathway for the formation of estrone from 19-HCA in
Moraxella
sp. has been proposed.
Production of 26-deoxymonensins A and B by Streptomyces cinnamonensis in the presence of Metyrapone
Authors: Pospísil S , Sedmera P , Havlícek V , Tax J
Published: January 2020

Metyrapone, a potent cytochrome P-450 inhibitor, added at 9 mM to a submerged culture of Streptomyces cinnamonensis caused partial inhibition of total monensin biosynthesis and coproduction of new metabolites, 26-deoxymonensins A and B. The latter was isolated as its 25-O-methyl derivative. Metyrapone was simultaneously reduced to metyrapol. All of these compounds were identified by nuclear magnetic resonance spectroscopy and mass spectrometry.
Effect of the Squid Host on the Abundance and Distribution of Symbiotic
Vibrio fischeri
in Nature
Authors: Lee Kyu-Ho , Ruby Edward G.
Published: January 2020

Euprymna scolopes,
a Hawaiian species of bioluminescent squid, harbors
Vibrio fischeri
as its specific light organ symbiont. The population of symbionts grew inside the adult light organ with an average doubling time of about 5 h, which produced an excess of cells that were expelled into the surrounding seawater on a diurnal basis at the beginning of each period of daylight. These symbionts, when expelled into the ambient seawater, maintain or slightly increase their numbers for at least 24 h. Hence, locations inhabited by their hosts periodically receive a daily input of symbiotic
V. fischeri
cells and, as a result, become significantly enriched with these bacteria. As estimated by hybridization with a species-specific
luxA
gene probe, the typical number of
V. fischeri
CFU, both in the water column and in the sediments of
E. scolopes
habitats, was as much as 24 to 30 times that in similar locations where squids were not observed. In addition, the number of symbiotic
V. fischeri
CFU in seawater samples that were collected along a transect through Kaneohe Bay, Hawaii, decreased as a function of the distance from a location inhabited by
E. scolopes.
These findings constitute evidence for the first recognized instance of the abundance and distribution of a marine bacterium being driven primarily by its symbiotic association with an animal host.
Influence of temperature and plumbing material selection on biofilm formation and growth of Legionella pneumophila in a model potable water system containing complex microbial flora
Authors: Rogers J , Dowsett A B , Dennis P J , Lee J V , Keevil C W
Published: January 2020

Survival and growth of Legionella pneumophila in both biofilm and planktonic phases were determined with a two-stage model system. The model used filter-sterilized tap water as the sole source of nutrient to culture a naturally occurring mixed population of microorganisms including virulent L. pneumophila. At 20 degrees C, L. pneumophila accounted for a low proportion of biofilm flora on polybutylene and chlorinated polyvinyl chloride, but was absent from copper surfaces. The pathogen was most abundant on biofilms on plastics at 40 degrees C, where it accounted for up to 50% of the total biofilm flora. Copper surfaces were inhibitory to total biofouling and included only low numbers of L. pneumophila organisms. The pathogen was able to survive in biofilms on the surface of the plastic materials at 50 degrees C, but was absent from the copper surfaces at the same temperature. L. pneumophila could not be detected in the model system at 60 degrees C. In the presence of copper surfaces, biofilms forming on adjacent control glass surfaces were found to incorporate copper ions which subsequently inhibited colonization of their surfaces. This work suggests that the use of copper tubing in water systems may help to limit the colonization of water systems by L. pneumophila.
Expression of ovine gamma interferon in Escherichia coli and Corynebacterium glutamicum
Authors: Billman-Jacobe H , Hodgson A L , Lightowlers M , Wood P R , Radford A J
Published: January 2020

Bacteria of two species, Escherichia coli and Corynebacterium glutamicum, were used as hosts to express recombinant ovine gamma interferon as a fusion protein with glutathione S-transferase. The recombinant gamma interferon produced by both bacteria was biologically active in vitro and was recognized by anti-gamma interferon monoclonal antibodies. E. coli produced large amounts of soluble recombinant protein which could be purified by a simple affinity chromatography method. Only a small fraction of the recombinant protein made by C. glutamicum was recovered by this method. Expression of recombinant protein in C. glutamicum was unstable but could be controlled by increased regulation of the tac promoter. Both hosts expressed ovine gamma interferon at high levels, with the recombinant protein making up a significant proportion of the cellular protein content.
Cloning, expression, and nucleotide sequence of genes involved in production of lactococcin DR, a bacteriocin from lactococcus lactis subsp. lactis
Authors: Rince A , Dufour A , Le Pogam S , Thuault D , Bourgeois C M , Le Pennec J P
Published: January 2020

The partial nucleotide sequence of a Lactococcus lactis subsp. lactis ADRIA 85LO30 bacteriocin-producing operon was determined. The first two open reading frames of the operon are necessary to get bacteriocin expression in L. lactis IL1403R.
Comparison of respiratory activity and culturability during monochloramine disinfection of binary population biofilms
Authors: Stewart P S , Griebe T , Srinivasan R , Chen C I , Yu F P , deBeer D , McFeters G A
Published: January 2020

Biofilm bacteria challenged with monochloramine retained significant respiratory activity, even though they could not be cultured on agar plates. Microbial colony counts on agar media declined by approximately 99.9% after 1 h of disinfection, whereas the number of bacteria stained by a fluorescent redox dye experienced a 93% reduction. Integrated measures of biofilm respiratory activity, including net oxygen and glucose utilization rates, showed only a 10 to 15% reduction. In this biofilm system, measures of microbial respiratory activity and culturability yielded widely differing estimates of biocide efficacy.
Fumonisin production and other traits of Fusarium moniliforme strains from maize in northeast Mexico
Authors: Desjardins A E , Plattner R D , Nelson P E
Published: January 2020

Strains of Fusarium moniliforme from maize seed collected in four fields in northeast Mexico were tested for fumonisin production in culture, for sexual compatibility, and for vegetative compatibility by using non-nitrate-utilizing mutants. The test results indicate that a diverse population of fumonisin-producing strains of F. moniliforme (Gibberella fujikuroi) mating population A predominates and that a potential exists for production of fumonisins in Mexican maize.
Purification and characterization of the CelB endoglucanase from Streptomyces lividans 66 and DNA sequence of the encoding gene
Authors: Wittmann S , Shareck F , Kluepfel D , Morosoli R
Published: January 2020

The endoglucanase CelB isolated from culture filtrates of Streptomyces lividans IAF9 has an M(r) of 36,000. With carboxymethyl cellulose as the substrate, the Vmax and Km values are 110 IU/mg of enzyme and 1.3 mg/ml, respectively. Comparison of primary amino acid sequences classifies CelB in the H family of cellulases.
Catabolism of lysine in Penicillium chrysogenum leads to formation of 2-aminoadipic acid, a precursor of penicillin biosynthesis
Authors: Esmahan C , Alvarez E , Montenegro E , Martin J F
Published: January 2020

Penicillium chrysogenum L2, a lysine auxotroph blocked in the early steps of the lysine pathway before 2-aminoadipic acid, was able to synthesize penicillin when supplemented with lysine. The amount of penicillin produced increased as the level of lysine in the media was increased. The same results were observed in resting-cell systems. Catabolism of [U-14C]lysine by resting cells and batch cultures of P. chrysogenum L2 resulted in the formation of labeled saccharopine and 2-aminoadipic acid. Formation of [14C]saccharopine was also observed in vitro when cell extracts of P. chrysogenum L2 and Wis 54-1255 were used. Saccharopine dehydrogenase and saccharopine reductase activities were found in cell extracts of P. chrysogenum, which indicates that lysine catabolism may proceed by reversal of the two last steps of the lysine biosynthetic pathway. In addition, a high lysine:2-ketoglutarate-6-aminotransferase activity, which converts lysine into piperideine-6-carboxylic acid, was found in cell extracts of P. chrysogenum. These results suggest that lysine is catabolized to 2-aminoadipic acid in P. chrysogenum by two different pathways. The relative contribution of lysine catabolism in providing 2-aminoadipic acid for penicillin production is discussed.
Genotypic Diversity among
Bacillus cereus
and
Bacillus thuringiensis
Strains
Authors: Carlson Cathrine Rein , Caugant Dominique A. , Kolstø Anne-Brit
Published: January 2020

Twenty-four strains of
Bacillus cereus
were analyzed by pulsed-field gel electrophoresis (PFGE) and compared with 12
Bacillus thuringiensis
strains. In addition, the 36 strains were examined for variation in 15 chromosomal genes encoding enzymes (by multilocus enzyme electrophoresis [MEE]). The genome of each strain had a distinct
Not
I restriction enzyme digestion profile by PFGE, and the 36 strains could be assigned to 27 multilocus genotypes by MEE. However, neither PFGE nor MEE analysis could distinguish between the two species. Two of the
B. cereus
strains contained extrachromosomal DNA that hybridized to a
cryIA
insecticidal toxin probe, and seven strains contained DNA with homology to a Tn
4430
transposon probe derived from
B. thuringiensis.
The results strongly indicate that
B. cereus
and
B. thuringiensis
should be regarded as one species.
Agglutination, Adherence, and Root Colonization by Fluorescent Pseudomonads
Authors: Glandorf D. C. M. , van der Sluis I. , Anderson A. J. , Bakker P. A. H. M. , Schippers B.
Published: January 2020

Two fractions of agglutination activity towards fluorescent pseudomonads were detected in root washes of potato, tomato, wheat, and bean. High-molecular-mass (>10
6
Da) components in crude root washes agglutinated only particular saprophytic, fluorescent
Pseudomonas
isolates. Ion-exchange treatment of the crude root washes resulted in preparations of lower-molecular-mass (10
5
to 10
6
Da) fractions which agglutinated almost all
Pseudomonas
isolates examined. Also, components able to suppress agglutination reactions of pseudomonads with the lower-molecular-mass root components were detected in crude root washes of all crops studied.
Pseudomonas
isolates were differentially agglutinated by both types of root components. The involvement of these two types of root components in short-term adherence and in colonization was studied in potato, tomato, and grass, using
Pseudomonas
isolates from these crops. Short-term adherence of isolates to roots was independent of their agglutination with either type of root components. With agglutination-negative mutants, the high-molecular-mass components seemed to be involved in adherence of
Pseudomonas putida
Corvallis to roots of all crops studied. Short-term adherence to roots of four
Pseudomonas
isolates could be influenced by addition of both crude and ion-exchange-treated root washes, depending on their agglutination phenotype with these root wash preparations. Potato root colonization by 10 different isolates from this crop, over a period of 7 days, was not correlated with their agglutination phenotype. Agg
-
mutants of
P. putida
Corvallis were not impaired in root colonization. It is concluded that the root agglutinins studied can be involved in short-term adherence of pseudomonads to roots but do not play a decisive role in their root colonization.
A major Pseudomonas aeruginosa clone common to patients and aquatic habitats
Authors: Römling U , Wingender J , Müller H , Tümmler B
Published: January 2020

The genomic relatedness of 573 Pseudomonas aeruginosa strains from environmental and clinical habitats was examined by digesting the genome with the rare-cutting enzyme SpeI. Thirty-nine strains were collected from environmental habitats mainly of aquatic origin, like rivers, lakes, or sanitary facilities. Four hundred fifty strains were collected from 76 patients with cystic fibrosis (CF) treated at four different centers, and 25 additional clinical isolates were collected from patients suffering from other diseases. Twenty-nine P. aeruginosa isolates were collected from the environment of one CF clinic. Thirty strains from culture collections were of environmental and clinic origin. A common macrorestriction fingerprint pattern was found in 13 of 46 CF patients, 5 of 29 environmental isolates from the same hospital, in a single ear infection isolate from another hospital, and 8 of 38 isolates from aquatic habitats about 300 km away from the CF clinic. The data indicate that closely related variants of one major clone (called clone C) persisted in various spatially and temporally separated habitats. Southern analysis of the clonal variants with six gene probes and two probes for genes coding for rRNA revealed almost the same hybridization patterns. With the exception of the phenotypically rapidly evolving CF isolates, the close relatedness of the strains of the clone was also shown by their identical responses in pyocin typing, phage typing, and serotyping. Besides clone C, three other P. aeruginosa clones were isolated from more than one clinical or environmental source.
Genetic Structure and Symbiotic Characteristics of a
Bradyrhizobium
Population Recovered from a Pasture Soil
Authors: Bottomley Peter J. , Cheng Hsin-Hua , Strain Steven R.
Published: January 2020

We examined the genetic structure and symbiotic characteristics of
Bradyrhizobium
isolates recovered from four legume species (
Lupinus albus
[white lupine],
Lupinus angustifolius
[blue lupine],
Ornithopus compressus
[yellow serradella], and
Macroptilium atropurpureum
[sirato]) grown in an Oregon soil. We established that multilocus enzyme electrophoresis (MLEE) can provide insights into the genetic relatedness among
Bradyrhizobium
strains by showing a positive correlation (
r
2
= ≥0.90) between the relatedness of
Bradyrhizobium japonicum
strains determined by MLEE at 13 enzyme loci and that determined by other workers using either DNA-DNA hybridization or DNA sequence divergence estimates. MLEE identified 17 electrophoretic types (ETs) among 95
Bradyrhizobium
isolates recovered from the four hosts. Although the overall genetic diversity among the ETs (
H
= 0.69) is one of the largest measured to date in a local population of any soilborne bacterial species, there was no evidence of multilocus structure (linkage disequilibrium) within the population. The majority of the isolates (73%) were represented by two closely related ETs (2 and 3) which dominated the root nodules of white lupine, serradella, and siratro. In contrast, ET1 dominated nodules of blue lupine. Although representative isolates from all of the 17 ETs nodulated siratro, white lupine, blue lupine, and big trefoil (
Lotus pedunculatus
), they were either completely ineffective or poorly effective at fixing nitrogen on these hosts. Despite the widespread use of serradella as a surrogate host for lupine-nodulating bradyrhizobia, 7 of the 17 ETs did not nodulate this host, and the remaining 10 ETs were ineffective at fixing nitrogen.
Anaerobic Metabolism of Cyclohex-1-Ene-1-Carboxylate, a Proposed Intermediate of Benzoate Degradation, by
Rhodopseudomonas palustris
Authors: Perrotta Joseph A. , Harwood Caroline S.
Published: January 2020

Anaerobic benzoate degradation by the phototrophic bacterium
Rhodopseudomonas palustris
has been proposed to proceed via aromatic ring reduction reactions leading to cyclohex-1-ene-1-carboxyl-coenzyme A (CoA) formation. The alicyclic product is then proposed to undergo three β-oxidation-like modifications resulting in ring cleavage. Illuminated suspensions of benzoate-grown cells converted [7-
14
C]cyclohex-1-ene-1-carboxylate to intermediates that comigrated with cyclohex-1-ene-1-carboxyl-CoA, 2-hydroxycyclohexanecar-boxyl-CoA, 2-ketocyclohexanecarboxyl-CoA, and pimelyl-CoA by thin-layer chromatography. This set of intermediates was also formed by cells grown anaerobically or aerobically on cyclohex-1-ene-1-carboxylate, indicating that benzoate-grown and cyclohex-1-ene-1-carboxylate-grown cells degrade this alicyclic acid by the same catabolic route. Four enzymatic activities proposed to be required for conversion of cyclohex-1-ene-1-carboxylate to pimelyl-CoA were detected at 3- to 10-fold-higher levels in benzoate-grown cells than in succinate-grown cells. These were cyclohex-1-ene-1-carboxylate-CoA ligase, cyclohex-1-ene-1-carboxyl-CoA hydratase, 2-hydroxycyclohexanecarboxyl-CoA dehydrogenase, and 2-ketocyclohexanecarboxyl-CoA hydrolase (ring cleaving). Pimelyl-CoA was identified in hydrolase reaction mixtures as the product of alicyclic ring cleavage. The results provide a first demonstration of an alicyclic ring cleavage activity.
Anisaldehyde production and aryl-alcohol oxidase and dehydrogenase activities in ligninolytic fungi of the genus Pleurotus
Authors: Gutiérrez A , Caramelo L , Prieto A , Martínez M J , Martínez A T
Published: January 2020

A variety of simple aromatic compounds were identified in liquid cultures of the basidiomycetes Pleurotus cornucopiae, P. eryngii, P. floridanus, P. pulmonarius, P. ostreatus, and P. sajor-caju by using gas chromatography-mass spectrometry. Such compounds were detected in fungal cultures on lignin- and straw-containing media, but it was found that they were also produced in the absence of aromatic precursors. Anisylic and hydroxybenzylic compounds (such as alcohols, aldehydes, and acids) were identified, p-anisaldehyde being the most characteristic extracellular metabolite synthesized by these ligninolytic fungi. Small amounts of 3-chloro-p-anisaldehyde were also detected in several species. It is postulated that the balance between the more-or-less-oxidized aromatic compounds can be explained in terms of the activity of fungal enzymes, including aryl-alcohol oxidase and dehydrogenase. The former enzyme shows high affinity for p-anisyl alcohol, which is oxidized to p-anisaldehyde with production of H2O2. The aryl-alcohol dehydrogenase was detected only in the mycelium, where it reduces aromatic aldehydes in the presence of NADPH. Both enzymes could be involved in the redox cycling of these aromatic compounds, providing H2O2 to ligninolytic peroxidases.
Effect of Host Diet and Hindgut Microbial Composition on Cellulolytic Activity in the Hindgut of the American Cockroach,
Periplaneta americana
Authors: Gijzen Huub J. , van der Drift Chris , Barugahare Martin , op den Camp Huub J. M.
Published: January 2020

Cellulase activity measured as filter paper digesting activity (FPase) and carboxymethyl cellulase (CMCase) was demonstrated in hindgut extracts of the cockroach
Periplaneta americana.
The highest activities measured amounted to 0.89 and 0.12 U · ml
-1
for CMCase and FPase, respectively. The cellulolytic capacity of the hindgut population increased dramatically when protozoa were present, and the activities were found to vary depending on the feeding regimen. Cellulose-rich diets induced high protozoal numbers, resulting in a high cellulase activity. A close correlation was found between the number of
Nyctotherus ovalis
organisms, the major protozoans in the hindgut, and both FPase and CMCase activity. Since the numbers of this protozoan also correlated with the methane production of the insect, it appears that
N. ovalis
is responsible for the major part of cellulolytic and methanogenic activity found in the hindgut of
P. americana.
Substrate Preference in a Strain of
Megasphaera elsdenii
, a Ruminal Bacterium, and Its Implications in Propionate Production and Growth Competition
Authors: Hino Tsuneo , Shimada Kimiomi , Maruyama Takeshi
Published: January 2020

The NIAH 1102 strain of
Megasphaera elsdenii
utilized lactate in preference to glucose when the two substrates were present. Even when lactate was supplied to cells fermenting glucose, the cells switched substrate utilization from glucose to lactate and did not utilize glucose until lactate decreased to a low concentration (1 to 2 mM). Since substrate utilization was shifted gradually without intermittence, typical diauxic growth was not seen. The cyclic AMP content did not rise markedly with the shift in substrate utilization, suggesting that this nucleotide is not involved in the regulation of the shift. It was unlikely that propionate was produced from glucose, which was explicable by the fact that lactate racemase activity dropped rapidly with the exhaustion of lactate and cells actively fermenting glucose did not possess this enzyme. A coculture experiment indicated that
M. elsdenii
NIAH 1102 is overcome by
Streptococcus bovis
JB1 in the competition for glucose, mainly because
M. elsdenii
NIAH 1102 is obliged to utilize lactate produced by
S. bovis
JB1; i.e., glucose utilization by
M. elsdenii
NIAH 1102 is suppressed by the coexistence of
S. bovis
JB1.
Effect of dietary fiber on microbial activity and microbial gas production in various regions of the gastrointestinal tract of pigs
Authors: Jensen B B , Jørgensen H
Published: January 2020

The microbial activity, composition of the gas phase, and gas production rates in the gastrointestinal tract of pigs fed either a low- or a high-fiber diet were investigated. Dense populations of culturable anaerobic bacteria, high ATP concentrations, and high adenylate energy charges were found for the last third of the small intestine, indicating that substantial microbial activity takes place in that portion of the gut. The highest microbial activity (highest bacterium counts, highest ATP concentration, high adenylate energy charge, and low pH) was found in the cecum and proximal colon. Greater microbial activity was found in the stomach and all segments of the hindgut in the pigs fed the high-fiber diet than in the pigs fed the low-fiber diet. Considerable amounts of O2 were found in the stomach (around 5%), while the content of O2 in gas samples taken from all other parts of the gastrointestinal tract was < 1%. The highest concentrations and highest production rates for H2 were found in the last third of the small intestine. No methane could be detected in the stomach or the small intestine. The rate of production and concentration of methane in the cecum and the proximal colon were low, followed by a steady increase in the successive segments of the hindgut. A very good correlation between in vivo and in vitro measurements of methane production was found. The amount of CH4 produced by pigs fed the low-fiber diet was 1.4 liters/day per animal. Substantially larger amounts of CH4 were produced by pigs fed the high-fiber diet (12.5 liters/day)(ABSTRACT TRUNCATED AT 250 WORDS)
In situ detection of hepatitis A virus in cell cultures and shellfish tissues
Authors: Romalde J L , Estes M K , Szücs G , Atmar R L , Woodley C M , Metcalf T G
Published: January 2020

An in situ transcription method was developed to detect hepatitis A virus RNA in both cell cultures and shellfish tissues. Radiolabeled cDNA copies were synthesized in situ by reverse transcriptase-directed transcription after annealing with a specific primer to the viral RNA. Both tritium (3H) and 35S were useful in the in situ transcription reaction, but the use of 3H resulted in a lower background and finer detail in the localization of viral particles. Application of the method to different organs of oysters which had bioaccumulated hepatitis A virus allowed the first in situ localization of the virus, specifically in stomach and hepatopancreatic tissues.
Detection of hepatitis A virus in environmental samples by antigen-capture PCR
Authors: Deng M Y , Day S P , Cliver D O
Published: January 2020

The efficacy of the antigen-capture PCR (AC-PCR) method for the detection of hepatitis A virus (HAV) in environmental samples was demonstrated. HAV was captured from a seeded liquid waste or a shellfish sample with homologous antibody and then heat denatured and subjected to reverse transcription and the PCR, all in the same tube. Subsequently, the AC-PCR products were analyzed by oligonucleotide probe hybridization in solution, agarose gel electrophoresis, and autoradiography. The AC-PCR detected as little as 0.053 PFU of cell culture-adapted HAV strain HM175/18f. The results of cDNA-RNA hybridization indicated that the particle/PFU ratio of this virus strain is approximately 79:1. Therefore, the detection limit of the AC-PCR was estimated to be four virus particles. No amplified products were observed when poliovirus 1, coxsackievirus A9, coxsackievirus B3, echovirus 6, reovirus 1, adenovirus type 40, human rotavirus type 1, and bovine enterovirus type 2 were tested, confirming the specificity of the assay. There were no differences between the nucleotide sequences of AC-PCR products of HAV strain HM175/18f and the sequences of wild-type HAV strain HM175 derived from molecularly cloned cDNA. Of 121 waste and shellfish samples tested by both plaque assays (PA) in cell cultures and the AC-PCR, 81 (67%) were positive and 31 (26%) were negative as determined by both methods, whereas 9 (7%) were positive as determined by the AC-PCR and negative as determined by the PA, and none were positive as determined by the PA and negative as determined by the AC-PCR.
A Biological Sensor for Iron Available to Bacteria in Their Habitats on Plant Surfaces
Authors: Loper J. E. , Lindow S. E.
Published: January 2020

A sensor responsive to iron was constructed by fusing a promoterless ice nucleation activity gene (
inaZ
) to an iron-regulated promoter of a genomic region involved in pyoverdine (fluorescent siderophore) (
pvd
) production in
Pseudomonas syringae
. Cells of
Pseudomonas fluorescens
and
P. syringae
that contained the
pvd-inaZ
fusion expressed iron-responsive ice nucleation activity in the bean rhizosphere and phyllosphere, respectively, and in culture. Addition of Fe(III) to leaves or soil reduced the apparent transcription of the
pvd-inaZ
reporter gene, as shown by a reduction in the number of ice nuclei produced, indicating that Fe(III) was primarily responsible for mediating transcription of the
pvd-inaZ
gene even in natural environments. A
Pseudomonas
sp. strain having an intact
iceC
gene, which conferred Fe-insensitive expression of ice nucleation activity, was included in all studies to account for small strain- or environment-dependent differences in the ability of bacterial cells to produce ice nuclei. Thus, a comparison of the ice nucleation activity conferred by
pvd-inaZ
with the activity conferred by
iceC
revealed the bioavailability of iron in culture or natural habitats. The relative ice nucleation activities expressed by strains containing
iceC
or
pvd-inaZ
indicated that, while not abundant, Fe(III) is not present at extremely low concentrations at all microsites colonized by bacteria on plant surfaces. Biological sensors that are constructed by fusing
inaZ
to chemically responsive promoters provide a novel way to characterize chemical constituents of microbial habitats.
Evaluation of MK filters for recovery of enteroviruses from tap water
Authors: Ma J F , Naranjo J , Gerba C P
Published: January 2020

The MK filter is an electropositively charged filter that can be used to concentrate enteroviruses from large volumes (400 to 1,000 liters) of water. This filter is less expensive than the commonly used 1MDS electropositive filter. In this study, we compared the recovery of poliovirus 1 (PV1) and that of coxsackievirus B3 (CB3) from 378 liters of tap water, using both the MK and the 1MDS filters. Viruses were eluted from the filters with 3% beef extract buffered with 0.05 M glycine (pH 9.5) and reconcentrated via organic flocculation. At high virus inputs (approximately 10(6) PFU), the overall recovery (after elution and reconcentration) of PV1 and CB3 from tap water with the MK filter was less than that achieved with the 1MDS filter (P < 0.05). The recoveries of PV1 from tap water with the MK and 1MDS filters were 73.2% +/- 26% (n = 5 trials) and 90.2% +/- 5.9% (n = 5 trials), respectively. The recoveries of CB3 from tap water with the MK and 1MDS filters were 32.8% +/- 34.5% (n = 4 trials) and 95.8% +/- 12.0% (n = 4 trials), respectively. This study indicated that the MK filter consistently provided lower recovery, with wider variability, of PV1 and CB3 from tap water than the 1MDS filter.
Influence of temperature on growth rate and competition between two psychrotolerant Antarctic bacteria: low temperature diminishes affinity for substrate uptake
Authors: Nedwell D B , Rutter M
Published: January 2020

The growth kinetics of two psychrotolerant Antarctic bacteria, Hydrogenophaga pseudoflava CR3/2/10 (2/10) and Brevibacterium sp. strain CR3/1/15 (1/15), were examined over a range of temperatures in both batch culture and glycerol-limited chemostat cultures. The maximum specific growth rate (mu max) and Ks values for both bacteria were functions of temperature, although the cell yields were relatively constant with respect to temperature. The mu max values of both strains increased up to an optimum temperature, 24 degrees C for 2/10 and 20 degrees C for 1/15. Strain 1/15 might therefore be considered to be more psychrophilic than strain 2/10. For both bacteria, the specific affinity (mu max/Ks) for glycerol uptake was lower at 2 than at 16 degrees C, indicating a greater tendency to substrate limitation at low temperature. As the temperature increased from 2 to 16 degrees C, the specific affinity of 1/15 for glycerol increased more rapidly than it did for 2/10. Thus 1/15, on the basis of this criterion, was less psychrophilic than was 2/10. The steady-state growth kinetics of the two strains at 2 and 16 degrees C imply that 1/15 would be able to outgrow 2/10 only at relatively low substrate concentrations (< 0.32 g of glycerol.liter-1) and high temperatures (> 12 degrees C), which suggests that 1/15 has a less psychrotolerant survival strategy than does 2/10. Our data were compared with other data in the literature for bacteria growing at low temperatures. They also showed an increase of substrate-specific affinity with increasing temperature.(ABSTRACT TRUNCATED AT 250 WORDS)