bluuebunny/crossref_metadata_2025 huggingface dataset:
Immunochemical study of triton X-100-soluble surface components of slime-forming, encapsulated Streptococcus cremoris from the fermented milk product viili
Authors: Kontusaari S I , Vuokila P T , Forsén R I
Published: January 2020

Crossed immunoelectrophoresis was used to study Triton X-100-soluble cell components of Streptococcus cremoris T5 from viili. The antiserum was raised against whole cells, and the antigens extracted gave a complex precipitate pattern with 16 prominent and reproducible precipitates. The results of immunoadsorption experiments with whole cells suggest that six antigens are expressed on the cell surface, and the exposure of cell surface antigens is greater on cells from the early stationary growth phase than on those from the late exponential phase.
Biochemical and Immunological Study of Cell Envelope Proteins in Sulfate-Reducing Bacteria
Authors: Norqvist Anders , Roffey Roger
Published: January 2020

The envelope proteins of 5 strains of the genus
Desulfotomaculum
and 12 strains of the genus
Desulfovibrio
were studied by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting. The
Desulfovibrio
strains exhibited a typical gram-negative cell envelope, whereas the cell envelope of
Desulfotomaculum
strains appeared to be gram-positive. A close relationship between strains of
Desulfotomaculum nigrificans
was observed. A comparison between different species of
Desulfotomaculum
revealed some degree of similarity between
Desulfotomaculum nigrificans
and
Desulfotomaculum ruminis,
whereas
Desulfotomaculum orientis
seemed unique. The strains of
Desulfovibrio salexigens
were quite different from the strains of the other species of
Desulfovibrio
. In two of the strains of
Desulfovibrio desulfuricans,
a species-specific antigen was observed. The strains of
Desulfovibrio vulgaris, Desulfovibrio africanus,
and
Desulfovibrio gigas
and one strain of
Desulfovibrio desulfuricans
exhibited a similar outer membrane protein profile and also showed very similar antigenic reactions.
Cloning and expression of a Streptococcus cremoris proteinase in Bacillus subtilis and Streptococcus lactis
Authors: Kok J , van Dijl J M , van der Vossen J M , Venema G
Published: January 2020

Previously, curing experiments suggested that plasmid pWV05 (17.5 megadaltons [Md]) of Streptococcus cremoris Wg2 specifies proteolytic activity. A restriction enzyme map of pWV05 was constructed, the entire plasmid was subcloned in Escherichia coli with plasmids pBR329 and pACYC184. A 4.3-Md HindIII fragment could not be cloned in an uninterrupted way in E. coli but could be cloned in two parts. Both fragments showed homology with the 9-Md proteinase plasmid of S. cremoris HP. The 4.3-Md HindIII fragment was successfully cloned in Bacillus subtilis on plasmid pGKV2 (3.1 Md). Crossed immunoelectrophoresis of extracts of B. subtilis carrying the recombinant plasmid (pGKV500; 7.4 Md) showed that the fragment specifies two proteins of the proteolytic system of S. cremoris Wg2. PGKV500 was introduced in a proteinase-deficient Streptococcus lactis strain via protoplast transformation. Both proteins were also present in cell-free extracts of S. lactis(pGKV500). In S. lactis, pGKV500 enables the cells to grow normally in milk with rapid acid production, indicating that the 4.3-Md HindIII fragment of plasmid pWV05 specifies the proteolytic activity of S. cremoris Wg2.
Studies on Cellulose Hydrolysis by
Acetivibrio cellulolyticus
Authors: MacKenzie C. Roger , Bilous Doris , Patel Girishchandra B.
Published: January 2020

Acetivibrio cellulolyticus
extracellular cellulase extensively hydrolyzed crystalline celluloses such as Avicel (FMC Corp., Food and Pharmaceutical Products Div., Philadelphia, Pa.) but only if it was desalted and supplemented with Ca
2+
. The Ca
2+
effect was one of increased enzyme stability in the presence of the ion. Although preincubation of the cellulase complex at 40°C for 5 h without added Ca
2+
had a negligible effect on endoglucanase activity or on the subseqent hydrolysis of amorphous cellulose, the capacity of the enzyme to hydrolyze crystalline cellulose was almost completely lost. Adsorption studies showed that 90% of the Avicel-solubilizing component of the total enzyme preparation bound to 2% Avicel at 40°C. Under these conditions, only 15% of the endoglucanase and 25% of the protein present in the enzyme preparation adsorbed to the substrate. The protein profile of the bound enzyme, as analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, was complex and distinctly different from the profile observed for total cellulase preparations. The specific activity of
A. cellulolyticus
cellulase with respect to Avicel hydrolysis was compared with that of commercially available
Trichoderma reesei
cellulase.

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Formation of Filaments by
Pseudomonas putida
Authors: Jensen Rodney H. , Woolfolk Clifford A.
Published: January 2020

When
Pseudomonas putida
40 was grown on a variety of liquid media in which oxygen became a limiting factor during growth, the latter stages of growth involved the elongation of cells without septation, which can result in the complete filamentation of the culture (up to several hundred micrometers long). The filaments appeared to consist of a chain of protoplasts within a common sacculus. Later these filaments were capable of a rapid fragmentation by septation to give a population of ordinary rods with a corresponding increase in the number of viable particles but no appreciable change in total bacterial mass. Filamentation did not occur if slow growth rates were maintained by restriction of oxygen availability from the beginning of growth. In complex media filaments were not formed during growth on 1% peptone alone, but the addition of 0.1 M phosphate or 6.6 � 10
−4
M EDTA induced extensive filamentation that was reversed by the addition of 6.6 � 10
−4
M Mg
2+
. In minimal media a much higher Mg
2+
concentration than that required for active growth or present in the complex media was usually required for filamentation. A very narrow range of Mg
2+
concentration promoted filamentation, and this optimum differed markedly depending on the carbon source used. Other medium variations which influenced the level of filamentation are reported. We found that most strains of
P. putida
(including the neotype strain) and
P. fluorescens
gave filaments under the conditions developed with strain 40, whereas several strains of
P. aeruginosa
failed to give filaments on the same media.
Microbial Penetration through Nutrient-Saturated Berea Sandstone
Authors: Jenneman Gary E. , McInerney Michael J. , Knapp Roy M.
Published: January 2020

Penetration times and penetration rates for a motile
Bacillus
strain growing in nutrient-saturated Berea sandstone cores were determined. The rate of penetration was essentially independent of permeabilities above 100 mdarcys and rapidly declined for permeabilities below 100 mdarcys. It was found that these penetration rates could be grouped into two statistically distinct classes consisting of rates for permeabilities above 100 mdarcys and rates for those below 100 mdarcys. Instantaneous penetration rates were found to be zero order with respect to core length for cores with permeabilities above 100 mdarcys and first order with respect to core length for cores with permeabilities below 100 mdarcys. The maximum observed penetration rate was 0.47 cm � h
−1
, and the slowest was 0.06 cm � h
−1
; however, these rates may be underestimates of the true penetration rate, since the observed rates included the time required for growth in the flask as well as the core. The relationship of penetration time to the square of the length of the core suggested that cells penetrated high-permeability cores as a band and low-permeability cores in a diffuse fashion. The motile
Enterobacter aerogenes
strain penetrated Berea sandstone cores three to eight times faster than did the nonmotile
Klebsiella pneumoniae
strain when cores of comparable length and permeability were used. A penetration mechanism based entirely on motility predicted penetration times that were in agreement with the observed penetration times for motile strains. The fact that nonmotile strains penetrated the cores suggested that filamentous or unrestricted growth, or both, may also be important.
Growth Kinetics of Attached Iron-Oxidizing Bacteria
Authors: Wichlacz Paul L. , Unz Richard F.
Published: January 2020

A model of growth and substrate utilization for ferrous-iron-oxidizing bacteria attached to the disks of a rotating biological contactor was developed and tested. The model describes attached bacterial growth as a saturation function in which the rate of substrate utilization is determined by a maximum substrate oxidation rate constant (
P
), a half-saturation constant (
K

s

), and the concentration of substrate within the rotating biological contactor (
S
1
). The maximum oxidation rate constant was proportional to flow rate, and the substrate concentration in the reactor varied with influent substrate concentration (
S
0
). The model allowed the prediction of metabolic constants and included terms for both constant and growth-rate-dependent maintenance energies. Estimates for metabolic constants of the attached population of acidophilic, chemolithotrophic, iron-oxidizing bacteria limited by ferrous iron were: maximum specific growth rate (μ
max
), 1.14 h
−1
; half-saturation constant (
K

s

) for ferrous iron, 54.9 mg/liter; constant maintenance energy coefficient (
m
1
), 0.154 h
−1
; growth-rate-dependent maintenance energy coefficient (m′), 0.07 h
−1
; maximum yield (
Y

g

), 0.063 mg of organic nitrogen per mg of Fe(II) oxidized.
Immobilized
Clostridium acetobutylicum
P262 Mutants for Solvent Production
Authors: Largier Susan T. , Long Susan , Santangelo Joseph D. , Jones David T. , Woods David R.
Published: January 2020

The production of acetone, butanol, and ethanol by two immobilized, sporulation-deficient
(spo) Clostridium acetobutylicum
P262 mutants which were held in the solventogenic phase was investigated. The
spoA2
mutant, which was an early-sporulation mutant and did not form a forespore septum, produced higher solvent yields than did the
spoB
mutant which was a late-sporulation mutant and was blocked at a stage after forespore septum formation. The
spoA2
mutant was also granulose and capsule negative. In a conventional batch fermentation, the wild-type strain produced 15.44 g of solvents per liter after 50 h at a productivity of 7.41 g of solvents per liter per day. The
spoA2
mutant produced 15.42 g of solvents per liter at a productivity of 72.4 g of solvents per liter per day, with a retention time of 2.4 h in a continuous immobilized cell system employing a fluidized bed reactor. This represents a major advance, since the immobilization of wild-type cells showed similar increases in productivity but a ca. fivefold reduction in final product concentrations.
Droplet enrichment factors of pigmented and nonpigmented Serratia marcescens: possible selective function for prodigiosin
Authors: Burger S R , Bennett J W
Published: January 2020

Drops produced by bursting bubbles provide a mechanism for the water-to-air transfer and concentration of matter. Bacteria can adsorb to air bubbles rising through bacterial suspensions and enrich the drops formed by the bubbles upon breaking, creating atmospheric biosols which function in dispersal. This bacterial enrichment can be quantified as an enrichment factor (EF), calculated as the ratio of the concentration of bacteria in the drop to that of the bulk bacterial suspension. Bubbles were produced in suspensions of pigmented (prodigiosin-producing) and nonpigmented cultures of Serratia marcescens. EFs for pigmented cultures were greater than EFs for nonpigmented cells. Pigmented cells appeared hydrophobic based on their partitioning in two-phase systems of polyethylene glycol 6000 and dextran T500. The surface hydrophobicity of pigmented cells may result from the hydrophobic nature of prodigiosin and could account for the greater ability of these bacteria to adsorb to air bubbles and enrich airborne droplets. Enhancement of the aerosolization of S. marcescens may be a selective function of the bacterial secondary metabolite prodigiosin.
Sulfate-Reducing Bacteria: Principal Methylators of Mercury in Anoxic Estuarine Sediment
Authors: Compeau G. C. , Bartha R.
Published: January 2020

Substrate-electron acceptor combinations and specific metabolic inhibitors were applied to anoxic saltmarsh sediment spiked with mercuric ions (Hg
2+
) in an effort to identify, by a direct approach, the microorganisms responsible for the synthesis of hazardous monomethylmercury. 2-Bromoethane sulfonate (30 mM), a specific inhibitor of methanogens, increased monomethylmercury synthesis, whereas sodium molybdate (20 mM), a specific inhibitor of sulfate reducers, decreased Hg
2+
methylation by more than 95%. Anaerobic enrichment and isolation procedures yielded a
Desulfovibrio desulfuricans
culture that vigorously methylated Hg
2+
in culture solution and also in samples of presterilized sediment. The Hg
2+
methylation activity of sulfate reducers is fully expressed only when sulfate is limiting and fermentable organic substrates are available. To date, sulfate reducers have not been suspected of Hg
2+
methylation. Identification of these bacteria as the principal methylators of Hg
2+
in anoxic sediments raises questions about the environmental relevance of previous pure culture-based methylation work.
Partial purification and characterization of a polymannuronic acid depolymerase produced by a mucoid strain of Pseudomonas aeruginosa isolated from a patient with cystic fibrosis
Authors: Dunne W M , Buckmire F L
Published: January 2020

An exopolysaccharide depolymerase was isolated from a mucoid strain of Pseudomonas aeruginosa of cystic fibrosis origin. Purified preparations of the depolymerase showed maximum activity against the unacetylated polymannuronic acid exopolysaccharide from the same strain and little activity against commercially prepared alginic acid. The evidence suggests that the enzyme is either periplasmic in location or associated with the outer cell membrane and is released extracellularly, in the absence of cell lysis, after a reduction of the culture magnesium (Mg2+) concentration below 3.0 mM. The depolymerase is also released after the addition of sublethal concentrations of EDTA to cultures containing 3.0 mM Mg2+. A survey of additional mucoid P. aeruginosa isolates recovered from patients with cystic fibrosis showed that nearly 60% demonstrated similar depolymerase activity while none of the nonmucoid revertants of the parent strains produced detectable depolymerase activity.
Rapid detection of salmonellae by immunoassays with titanous hydroxide as the solid phase
Authors: Ibrahim G F , Lyons M J , Walker R A , Fleet G H
Published: January 2020

Radioimmunometric and enzyme-immunometric assays were developed for the detection of salmonellae in pure and mixed cultures as well as in 59 food samples. The performances of titanous hydroxide suspension and microtiter plates as the solid phase for the immobilization of microorganisms were compared in these immunoassays. Detection of populations of salmonella cells in pure culture, diluted with saline, was 4- to 10-fold more sensitive with the microtiter plates. However, with mixed culture of salmonella and other enterobacterial species, the detection sensitivity with titanous hydroxide was 100- to 160-fold more sensitive than with microtiter plates. Good correlation existed between results of a standard cultural method for the detection of salmonellae in foods and those obtained from radioimmunometric and enzyme-immunometric assays utilizing titanous hydroxide. However, a high incidence of false-positive and false-negative results with food samples occurred with the enzyme-immunometric assay utilizing microtiter plates. The results provided strong evidence for the merits of substituting titanous hydroxide for microtiter plates as the solid phase for the immobilization of salmonellae for their detection by immunoassays. The immunoassays were rapid and enabled the analysis of a large number of selective enrichment cultures of food samples for salmonellae within 8 h.
Cellulose Decomposition and Associated Nitrogen Fixation by Mixed Cultures of
Cellulomonas gelida
and
Azospirillum
Species or
Bacillus macerans
Authors: Halsall Dorothy M. , Gibson Alan H.
Published: January 2020

Mixed cultures of
Cellulomonas gelida
plus
Azospirillum lipoferum
or
Azospirillum brasilense
and
C. gelida
plus
Bacillus macerans
were shown to degrade cellulose and straw and to utilize the energy-yielding products to fix atmospheric nitrogen. This cooperative process was followed over 30 days in sand-based cultures in which the breakdown of 20% of the cellulose and 28 to 30% of the straw resulted in the fixation of 12 to 14.6 mg of N per g of cellulose and 17 to 19 mg of N per g of g straw consumed.
Cellulomonas
species have certain advantages over aerobic cellulose-degrading fungi in being able to degrade cellulose at oxygen concentrations as low as 1% O
2
(vol/vol) which would allow a close association between cellulose-degrading and microaerobic diazotrophic microorganisms. Cultures inoculated with initially different proportions of
A. brasilense
and
C. gelida
all reached a stable ratio of approximately 1
Azospirillum
/3
Cellulomonas
cells.
Transmembrane pH gradient and membrane potential in Clostridium acetobutylicum during growth under acetogenic and solventogenic conditions
Authors: Huang L , Gibbins L N , Forsberg C W
Published: January 2020

The proton motive force and its electrical and chemical components were determined in Clostridium acetobutylicum, grown in a phosphate-limited chemostat, using [14C]dimethyloxazolidinedione and [14C]benzoic acid as transmembrane pH gradient (delta pH) probes and [14C]triphenylmethylphosphonium as a membrane potential (delta psi) indicator. The cells maintained an internal-alkaline pH gradient of approximately 0.2 at pH 6.5 and 1.5 at pH 4.5. The delta pH was essentially constant between pH 6.5 and 5.5 but increased considerably at lower extracellular pH values down to 4.5. Hence, the intracellular pH fell from 6.7 to 6.0 as the external pH was lowered from 6.5 to 5.5 but did not decrease further when the external pH was decreased to 4.5. The transmembrane electrical potential decreased as the external pH decreased. At pH 6.5, delta psi was approximately -90 mV, whereas no negative delta psi was detectable at pH 4.5. The proton motive force was calculated to be -106 mV at pH 6.5 and -102 mV at pH 4.5. The ability to maintain a high internal pH at a low extracellular pH suggests that C. acetobutylicum has an efficient deacidification mechanism which expresses itself through the production of neutral solvents.
Xylanolytic Activity of
Clostridium acetobutylicum
Authors: Lee Song F. , Forsberg Cecil W. , Gibbins L. N.
Published: January 2020

Of 20 strains of
Clostridium
spp. screened, 17 hydrolyzed larch wood xylan. Two strains of
Clostridium acetobutylicum,
NRRL B527 and ATCC 824, hydrolyzed xylan but failed to grow on solid media with larch xylan as the sole carbon source; however, strain ATCC 824 was subsequently found to grow on xylan under specified conditions in a chemostat. These two strains possessed cellulolytic activity and were therefore selected for further studies. In cellobiose-limited continuous cultures, strain NRRL B527 produced maximum xylanase activity at pH 5.2. Strain ATCC 824 produced higher xylanase, xylopyranosidase, and arabinofuranosidase activities in chemostat culture with xylose than with any other soluble carbon source as the limiting nutrient. The activities of these enzymes were markedly reduced when the cells were grown in the presence of excess glucose. The xylanase showed maximum activity at pH 5.8 to 6.0 and 65�C. The enzyme was stable on the alkaline side of pH 5.2 but was unstable below this pH value. The extracellular xylanolytic activity from strain ATCC 824 hydrolyzed 12% of the larch wood xylan during a 24-h incubation period, yielding xylose, xylobiose, and xylotriose as the major hydrolysis products. Strain ATCC 824, after being induced to grow in batch culture in xylan medium supplemented with a low concentration of xylose, failed to grow reproducibly in unsupplemented xylan medium. A mutant obtained by mutagenesis with ethyl methanesulfonate was able to grow reproducibly in batch culture on xylan. Both the parent strain and the mutant were able to grow with xylan as the sole source of carbohydrate in continuous culture with the pH maintained at either 5.2 or 6.0. Under these conditions, the cells utilized approximately 50% of the xylan.
Galactokinase activity in Streptococcus thermophilus
Authors: Hutkins R , Morris H A , McKay L L
Published: January 2020

ATP-dependent phosphorylation of [14C]galactose by 11 strains of Streptococcus thermophilus indicated that these organisms possessed the Leloir enzyme, galactokinase (galK). Activities were 10 times higher in fully induced, galactose-fermenting (Gal+) strains than in galactose-nonfermenting (Gal-) strains. Lactose-grown, Gal- cells released free galactose into the medium and were unable to utilize residual galactose or to induce galK above basal levels. Gal+ S. thermophilus 19258 also released galactose into the medium, but when lactose was depleted growth on galactose commenced, and galK increased from 0.025 to 0.22 micromol of galactose phosphorylated per min per mg of protein. When lactose was added to galactose-grown cells of S. thermophilus 19258, galK activity rapidly decreased. These results suggest that galK in Gal+ S. thermophilus is subject to an induction-repression mechanism, but that galK cannot be induced in Gal- strains.
Occurrence and properties of bacteriophages of Leuconostoc oenos in Australian wines
Authors: Davis C , Silveira N F , Fleet G H
Published: January 2020

Bacteriophages specific for Leuconostoc oenos were isolated from four red wines undergoing malolactic fermentation in one winery. Bacteriophages were not found in samples of 16 other wines. The morphology of the phages was examined by electron microscopy. The phages did not lyse all strains of L. oenos, and susceptibility correlated to some extent with the colony morphology of the strain. Phage survived in wines at pH values greater than 3.5 but was inactivated in wines of lower pH and by the addition of sulfur dioxide or bentonite. Phage did not affect the growth of a sensitive strain of L. oenos in filter-sterilized wine.
Identification of thermophilic bacteria in solid-waste composting
Authors: Strom P F
Published: January 2020

The thermophilic microbiota of solid-waste composting, with major emphasis on Bacillus spp., was examined with Trypticase soy broth (BBL Microbiology Systems) with 2% agar as the initial plating medium. Five 4.5-liter laboratory units at 49 to 69 degrees C were fed a mixture of dried table scraps and shredded newspaper. The composting plants treating refuse at Altoona, Pa., and refuse-sludge at Leicester, England, were also sampled. Of 652 randomly picked colonies, 87% were identified as Bacillus spp. Other isolates included two genera of unidentified nonsporeforming bacteria (one of gram-negative small rods and the other of gram-variable coccobacilli), the actinomycetes Streptomyces spp. and Thermoactinomyces sp., and the fungus Aspergillus fumigatus. Among the Bacillus isolates, the following, in order of decreasing frequency, were observed: B. circulans complex, B. stearothermophilus, B. coagulans types A and B, B. licheniformis, B. brevis, B. sphaericus, Bacillus spp. types i and ii, and B. subtilis. About 15% of the Bacillus isolates could be assigned to species only by allowing for greater variability in one or more characteristics than has been reported by other authors for their strains. In particular, growth at higher temperatures than previously reported was found for strains of several species. A small number of Bacillus isolates (less than 2%) could not be assigned to any recognized species.
Degradation of phenol by Pseudomonas putida ATCC 11172 in continuous culture at different ratios of biofilm surface to culture volume
Authors: Molin G , Nilsson I
Published: January 2020

Pseudomonas putida ATCC 11172 was grown in continuous culture with phenol as the only carbon and energy source; a culture practically without biofilm was compared with biofilm cultures of differing surface area/volume ratios. The biofilm did not significantly affect the maximal suspended cell concentration in the effluent, but it increased the maximal phenol reduction rate from 0.23 g/liter per h (without biofilm) to 0.72 g/liter per h at the highest biofilm level (5.5 cm2 of biofilm surface per ml of reactor volume). The increase in phenol reduction rate was linear up to the surface area/volume ratio of 1.4 cm2/ml. The continuous cultures with biofilms could tolerate a higher phenol concentration of the medium (3.0 g/liter) than the nonbiofilm system (2.5 g/liter). At higher dilution rates an intermediate product, 2-hydroxymuconic semialdehyde, accumulated in the culture. When the biomass of the effluent started to decrease, the concentration of 2-hydroxymuconic semialdehyde reached a peak value. We conclude that biofilms in continuous culture have the potential to enhance the aerobic degradation of aromatic compounds.
Isolation and characterization of butanol-resistant mutants of Clostridium acetobutylicum
Authors: Hermann M , Fayolle F , Marchal R , Podvin L , Sebald M , Vandecasteele J P
Published: January 2020

In a wild-type strain of Clostridium acetobutylicum isolated from soil, solvent production appeared limited by butanol toxicity. Butanol-resistant mutants have been obtained which produced significantly higher solvent concentrations (about 30%) than the wild-type strain. Some other physiological differences were observed between a selected resistant mutant and the wild-type strain at the level of solvent resistance and sporulation.
Interactions in Syntrophic Associations of Endospore-Forming, Butyrate-Degrading Bacteria and H
2
-Consuming Bacteria
Authors: Tomei Francisco A. , Maki James S. , Mitchell Ralph
Published: January 2020

Butyrate is an important intermediate in the anaerobic degradation of organic matter. In sulfate-depleted environments butyrate is oxidized to acetate and hydrogen by obligate proton reducers, in syntrophic association with hydrogen-consuming methanogens. This paper describes two enrichments of endospore-forming bacteria degrading butyrate in consortia with methanogens. The isolates are readily established in coculture with H
2
-consuming, sulfate-reducing bacteria by pasteurizing the culture. The two original enrichments differed in that one grew to an optically dense culture while the second grew in clumps. Examination by scanning electron microscopy showed that clumping resulted from the production of large amounts of extracellular polymer. Several H
2
-consuming methanogens were identified in the enrichments. Some of them grew closely associated to the butyrate degraders. This attachment to the hydrogen producer may permit some methanogens to compete for the growth substrate against other bacteria having higher substrate affinity.
Production of Ligninases and Degradation of Lignin in Agitated Submerged Cultures of
Phanerochaete chrysosporium
Authors: Jäger Alexander , Croan Suki , Kirk T. Kent
Published: January 2020

Research on the extracellular hemeprotein ligninases of
Phanerochaete chrysosporium
has been hampered by the necessity to produce them in stationary culture. This investigation examined the effects of detergents on development of ligninase activity in agitated submerged cultures. Results show that addition of Tween 80, Tween 20, or 3-[(3-colamidopropyl)dimethylammonio]1-propanesulfonate to the cultures permits development of ligninase activity comparable to that routinely obtained in stationary cultures. The detergent-amended cultures express the entire ligninolytic system, assayed as the complete oxidation of [
14
C]lignin to
14
CO
2
. The detergent effect is evidently not merely in facilitating release of extant enzyme. Development of ligninolytic activity in the agitated cultures, as in stationary cultures, is idiophasic. Ion-exchange fast protein-liquid chromatography indicated that the heme protein profiles in agitated and stationary cultures are very similar. These findings should make it possible to scale up production of ligninolytic enzymes in stirred tank fermentors.
Nutrient-Enhanced Production of Remarkably High Concentrations of Ethanol by
Saccharomyces bayanus
through Soy Flour Supplementation
Authors: Viegas Cristina A. , Sá-Correia Isabel , Novais Julio M.
Published: January 2020

The supplementation of a simple medium with soy flour led to an increase in the specific growth rate and viable cell concentration of
Saccharomyces bayanus
during fermentation. Increasing the amount of soy flour led to an increase in the maximum number of viable yeast cells and the percentage of glucose fermented. It was possible in 64 h to reach 12.8% (wt/vol) ethanol by adding 4% soy flour (wt/vol) to a simple medium with 300 g of glucose per liter. The aqueous extract from soy flour was nearly as effective as whole-soy flour, whereas the lipidic fraction had no positive effect.
Preparation and testing of an autolysate of fish viscera as growth substrate for bacteria
Authors: Clausen E , Gildberg A , Raa J
Published: January 2020

The aqueous soluble phase of acidified and autolyzed fish viscera was used as the nitrogen source in a growth medium for bacteria. The bacteria tested grew faster and produced higher yields of cell mass on this growth medium than on corresponding media with standard tryptone preparations as the nitrogen source.
Evidence for Plasmid Linkage of Raffinose Utilization and Associated α-Galactosidase and Sucrose Hydrolase Activity in
Pediococcus pentosaceus
Authors: Gonzalez Carlos F. , Kunka Blair S.
Published: January 2020

The ability to ferment the trisaccharide raffinose was linked with the presence of plasmid DNA in three strains of
Pediococcus pentosaceus.
Parental strains showed associated inducible α-galactosidase and sucrose hydrolase activities when grown in α-galactosides and sucrose, respectively. Derivative strains of PPE1.0, PPE2.0, and PPE5.0, which had lost 30-, 28-, and 23-megadalton plasmids, respectively, had no α-galactosidase or sucrose hydrolase activity.
Methods for Measuring Specific Rates of Mercury Methylation and Degradation and Their Use in Determining Factors Controlling Net Rates of Mercury Methylation
Authors: Ramlal Patricia S. , Rudd John W. M. , Hecky Robert E.
Published: January 2020

A method was developed to estimate specific rates of demethylation of methyl mercury in aquatic samples by measuring the volatile
14
C end products of
14
CH
3
HgI demethylation. This method was used in conjunction with a
203
Hg
2+
radiochemical method which determines specific rates of mercury methylation. Together, these methods enabled us to examine some factors controlling the net rate of mercury methylation. The methodologies were field tested, using lake sediment samples from a recently flooded reservoir in the Southern Indian Lake system which had developed a mercury contamination problem in fish. Ratios of the specific rates of methylation/demethylation were calculated. The highest ratios of methylation/demethylation were calculated. The highest ratios of methylation/demethylation occurred in the flooded shorelines of Southern Indian Lake. These results provide an explanation for the observed increases in the methyl mercury concentrations in fish after flooding.
Production of High-Viscosity Whey-Glucose Broths by a
Xanthomonas campestris
Strain
Authors: Schwartz Robert D. , Bodie Elizabeth A.
Published: January 2020

Crude broth viscosities, as high as 700 centipoise at a 12-s
−1
shear rate, were produced by fermenting a whey-glucose medium with a
Xanthomonas campestris
strain.
Large Plasmids from Soil Bacteria Enriched on Halogenated Alkanoic Acids
Authors: Hardman David J. , Gowland Peter C. , Slater J. Howard
Published: January 2020

Four
Pseudomonas
species and two
Alcaligenes
species were isolated from soil with a capacity to grow on halogenated alkanoic acids. They were shown to contain one of five large plasmids. The plasmids had molecular weights ranging from 98,800 to 190,000. They were associated with the ability to utilize the halogenated substrates 2-monochloropropionic acid and 2-monochloroacetic acid and with resistance towards one or more of the heavy metals mercury, selenium, and tellurium. The largest plasmid, pUU204, was shown to be unstable in continuous-flow culture when the organism was supplied with succinate as the sole carbon source. The dehalogenase gene associated with pUU204 appeared to be readily transferred to an incP group plasmid, R68-45.
Partial characterization of the genetic basis for sucrose metabolism and nisin production in Streptococcus lactis
Authors: Steele J L , McKay L L
Published: January 2020

We attempted to identify the genetic loci for sucrose-fermenting ability (Suc+), nisin-producing ability (Nip+), and nisin resistance (Nisr) in certain strains of Streptococcus lactis. To obtain genetic evidence linking the Suc+ Nip+ Nisr phenotype to a distinct plasmid, both conjugal transfer and transformation were attempted. A conjugation procedure modified to protect the recipients against the inhibitory action of nisin allowed the conjugal transfer of the Suc+ Nip+ Nisr marker from three Suc+ Nip+ Nisr donors to various recipients. The frequency of transfer ranged from 1.7 x 10(-4) to 5.6 x 10(-8) per input donor, depending on the mating pair. However, no additional plasmid DNA was apparent in these transconjugants. Transformation of S. lactis LM0230 to the Suc+ Nip+ Nisr phenotype by using the plasmid pool of S. lactis ATCC 11454 was not achieved, even though other plasmids present in the pool were successfully transferred. However, two results imply the involvement of plasmid DNA in coding for the Suc+ Nip+ Nisr phenotype. The Suc+ Nip+ Nisr marker was capable of conjugal transfer to a recipient deficient in host-mediated homologous recombination (Rec-), and the Suc+ Nip+ Nisr marker exhibited bilateral plasmid incompatibility with a number of lactose plasmids found in S. lactis. Although our results indicate that the Suc+ Nip+ Nisr phenotype is plasmid encoded, no physical evidence linking this phenotype to a distinct plasmid was obtained.
Generation and Characterization of Tn
5
Insertion Mutations in
Pseudomonas syringae
pv.
tomato
Authors: Cuppels Diane A.
Published: January 2020

Tn
5
-induced insertion mutations were generated in the
Pseudomonas syringae
pv.
tomato
genome by mating this plant pathogen with an
Escherichia coli
strain carrying the suicide plasmid vector for Tn
5
, pGS9. Km
r
transconjugants occurred at frequencies ranging from 2 × 10
−7
to 9 × 10
−6
; approximately 5.5% of these transconjugants were also Cm
r
, indicating the presence of additional pGS9 DNA sequences. Approximately 1% of the Km
r
Cm
s
mutants were auxotrophic. Southern blot analysis revealed that the Tn
5
element had inserted into one unique site on the chromosome for each Km
r
Cm
s
transconjugant examined. Physical and genetic tests of Tn
5
-induced auxotrophs showed that Tn
5
mutations in
P. syringae
pv.
tomato
were very stable and that secondary transposition of Tn
5
or its insertion sequence IS
50
was a rare event. Nine of 920 Km
r
Cm
s
transconjugants screened on tomato seedlings either were avirulent or produced very mild symptoms. Each of the virulence mutants was the result of a unique single-site Tn
5
insertion. Five mutants also failed to induce a hypersensitivity reaction on tobacco.
Transition from Anoxygenic to Oxygenic Photosynthesis in a
Microcoleus chthonoplastes
Cyanobacterial Mat
Authors: Jørgensen Bo Barker , Cohen Yehuda , Revsbech Niels Peter
Published: January 2020

Benthic cyanobacterial mats with the filamentous
Microcoleus chthonoplastes
as the dominant phototroph grow in oxic hypersaline environments such as Solar Lake, Sinai. The cyanobacteria are in situ exposed to chemical variations between 200 μmol of sulfide liter
−1
at night and 1 atm pO
2
during the day. During experimental H
2
S to O
2
transitions the microbial community was shown to shift from anoxygenic photosynthesis, with H
2
S as the electron donor, to oxygenic photosynthesis.
Microcoleus
filaments could carry out both types of photosynthesis concurrently. Anoxygenic photosynthesis dominated at high sulfide levels, 500 μmol liter
−1
, while the oxygenic reaction became dominant when the sulfide level was reduced below 100 to 300 μmol liter
−1
(25 to 75 μmol of H
2
S liter
−1
). An increasing inhibition of the oxygenic photosynthesis was observed upon transition to oxic conditions from increasing sulfide concentrations. Oxygen built up within the
Microcoleus
layer of the mat even under 5 mmol of sulfide liter
−1
(500 μmol of H
2
S liter
−1
) in the overlying water. The implications of such a localized O
2
production in a highly reducing environment are discussed in relation to the evolution of oxygenic photosynthesis during the Proterozoic era.
Restriction Endonuclease and
nif
Homology Patterns of
Bradyrhizobium japonicum
USDA 110 Derivatives With and Without Nitrogen Fixation Competence
Authors: Mathis James N. , Kuykendall L. David , Elkan Gerald H.
Published: January 2020

DNAs from
Bradyrhizobium japonicum
USDA 110 derivatives that differ in nitrogen-fixing ability produced similar electrophoretic patterns with five different restriction enzymes. Our data support the hypothesis of common ancestry for these derivatives. Derivatives I-110 and L1-110 differed as much as 100-fold in acetylene reduction activity when they were tested with several soybean cultivars in both greenhouse and field experiments. While possessing nodulating ability, derivative L1-110 is deficient in symbiotic nitrogen-fixing ability, whereas derivative I-110 is symbiotically competent. Hybridization of
nifDK
and
nifH
probes from
B. japonicum
to Southern blots of restricted DNAs from strain USDA 110 derivatives produced similar patterns. This finding indicates similar structural gene organization for both derivative I-110 and derivative L1-110 and implies that the difference in symbiotic nitrogen fixation is probably not due to structural gene rearrangements. However, our hybridization data do not rule out the possibility of differences in expression of structural
nif
genes or alterations in the structure or expression of other genes required for symbiotic nitrogen fixation.
Serotyping of Vibrio anguillarum
Authors: Sørensen U B , Larsen J L
Published: January 2020

A serotyping scheme based on the detection of O antigens by slide agglutination in fish-pathogenic strains of Vibrio anguillarum is presented. Over a period of 5 years 270 Vibrio strains from feral and cultured fish, 189 strains from the environment, and 36 strains from invertebrates were collected. The strains were divided into 10 distinct serotypes (O1 through O10). More than 90% of the fish-pathogenic strains, but only 40% of the environmental strains, were typable; 71% of the strains isolated from cultured rainbow trout were serotype O1, whereas 78% of the strains isolated from feral fish were serotype O2. No dominating environmental serotype was found. A serotyping system for V. anguillarum is proposed. A total of 90 strains received from culture collections and laboratories in different countries were typed according to the present system.
Mode of Action of Bipyramidal δ-Endotoxin of
Bacillus thuringiensis
subsp.
kurstaki
HD-1
Authors: Tojo Akihiko
Published: January 2020

The mode of action of the toxic fragment (P-59) derived from bipyramidal-shaped δ-endotoxin of
Bacillus thuringiensis
subsp.
kurstaki
HD-1 on the silkworm
Bombyx mori
was investigated. An enzyme-linked immunosorbent assay showed that there was no translocation of P-59 from the gut lumen to the hemocoel. When membrane vesicles prepared from silkworm midgut were incubated with P-59, normally smooth surface of vesicles became rough, and patch formation was observed on the surface. Vesicles treated with P-59 tended to agglutinate. The vesicle-denaturing activity of a 130,000-dalton subunit protein of bipyramidal toxin was enhanced by treatment with a gut juice protease of the silkworm. P-59 did not cause any uncoupling effect on mitochondria of the silkworm midgut. These results suggest that the attacking site of this toxin is not the mitochondrion but the cell membrane of the susceptible cell.
Adsorption of
Agrobacterium tumefaciens
to Susceptible Potato Tissues: a Physisorption Process
Authors: Kluepfel Daniel A. , Pueppke Steven G.
Published: January 2020

Adsorption of
Agrobacterium tumefaciens
cells to potato tuber disks reached equilibrium after coincubation for about 30 min. More than 10% of the number of bacteria bound at equilibrium were adsorbed within 30 s. Adsorption isotherms obtained at three temperatures showed that the heat of adsorption was nearly zero.
Growth of Pseudomonas aeruginosa on nitrous oxide
Authors: Bazylinski D A , Soohoo C K , Hollocher T C
Published: January 2020

Three strains of Pseudomonas aeruginosa were grown anaerobically on exogenous N2O in a defined medium under conditions that assured the maintenance of highly anaerobic conditions for periods of 1 week or more. The bacteria were observed reproducibly to increase their cell density by factors of 3 to 9, but not more, depending on the initial amount of N2O. Growth on N2O was cleanly blocked by acetylene. Cell yields, CO2 production, and N2O uptake all increased with initial PN2O at PN2O less than or equal to 0.1 atm. Growth curves were atypical in the sense that growth rates decreased with time. This is the first observation of growth of P. aeruginosa on N2O as the sole oxidant. N2O was shown to be an obligatory, freely diffusible intermediate during growth of strains PAO1 and P1 on nitrate. All three strains used this endogenous N2O efficiently for growth. For strains PAO1 and P1, it was confirmed that exogenous N2O had little effect on the cell yields of cultures growing with nitrate; thus, for these strains exogenous N2O neither directly inhibited growth nor was used significantly for growth. On the other hand, strain P2 grew abundantly on exogenous N2O when small and growth-limiting concentrations of nitrate or nitrate (2 to 10 mM) were included in the medium. The dramatic effect of these N-anions was realized in large part even when the exogenous N2O was introduced immediately after the quantitative conversion of anion-nitrogen to N2. No evidence was found for a factor in filter-sterilized spent medium that stimulated fresh inocula to grow abundantly on N2O.(ABSTRACT TRUNCATED AT 250 WORDS)
Isolation of Endoglucanase Genes from
Pseudomonas fluorescens
subsp.
cellulosa
and a
Pseudomonas
sp
Authors: Wolff Bruce R. , Mudry Terry A. , Glick Bernard R. , Pasternak J. J.
Published: January 2020

Endoglucanase genes from
Pseudomonas fluorescens
subsp.
cellulosa
and
Pseudomonas
sp. were cloned and characterized. DNA hybridization studies showed that these genes are homologous and that each species has one copy of the gene per genome. The DNA fragment from
Pseudomonas
sp. codes for, at most, a 23-kilodalton endoglucanase.
Improved immunological membrane filter method for detection of food-borne Salmonella strains
Authors: Cerqueira-Campos M L , Peterkin P I , Sharpe A N
Published: January 2020

An improved membrane filter method that involves the use of an enzyme-labeled antibody stain has been developed for the rapid detection of Salmonella species in foods. The procedure is carried out directly on a hydrophobic grid-membrane filter without requiring transfer by blotting to nitrocellulose. Pure cultures of 54 Salmonella species and 10 foods artificially contaminated with Salmonella colindale gave a positive reaction in which Salmonella colonies were visible as purple dots. Of 11 nonsalmonella organisms, only Citrobacter freundii reacted with Spicer-Edwards antiserum. Of 22 naturally contaminated food samples, 10 were positive for both the hydrophobic grid-membrane filter procedure of the Association of Official Analytical Chemists and the improved enzyme-labeled antibody stain method, and there was perfect agreement between the methods. Of these 10 positive samples, one was negative by the Health Protection Branch method; of the negative samples, two were positive by this latter method. The improved enzyme-labeled antibody stain method allows detection of Salmonella spp. in foods within 48 h, requires little equipment, and is inexpensive, easy to perform, and suitable for automated detection.
Intracellular Conditions Required for Initiation of Solvent Production by
Clostridium acetobutylicum
Authors: Terracciano Joseph S. , Kashket Eva R.
Published: January 2020

We investigated the intracellular physiological conditions associated with the induction of butanol-producing enzymes in
Clostridium acetobutylicum
. During the acidogenic phase of growth, the internal pH decreased in parallel with the decrease in the external pH, but the internal pH did not go below 5.5 throughout batch growth. Butanol was found to dissipate the proton motive force of fermenting
C. acetobutylicum
cells by decreasing the transmembrane pH gradient, whereas the membrane potential was affected only slightly. In growing cells, the switch from acid to solvent production occurred when the internal undissociated butyric acid concentration reached 13 mM and the total intracellular undissociated acid concentration (acetic plus butyric acids) was at least 40 to 45 mM. Similar values were obtained when cultures were supplemented with 50 mM butyric acid initially or when a phosphate-buffered medium was used instead of an acetate-buffered medium. To measure the induction of the enzymes involved in solvent synthesis, we determined the rates of conversion of butyrate to butanol in growing cells. The rate of butanol formation reached a maximum in the mid-solvent phase, when the butanol concentration was 50 mM. Although more solvent accumulated later, de novo enzyme synthesis decreased and then ceased.
Identification of Eubacteria Isolated from Leaf Cavities of Four Species of the N-Fixing
Azolla
Fern as
Arthrobacter
Conn and Dimmick
Authors: Wallace W. H. , Gates J. E.
Published: January 2020

The nutritional and physiological characteristics of 15 isolates from four species of the
Azolla
fern were determined. Although some minor variation existed in levels of urease activity, ability to utilize xylose, and formation of N
2
gas from NO
3
, all 15 isolates were rather similar and believed to represent a single species. These eubacteria exhibited aminopeptidase activity and became viscous when treated with KOH, similar to gram-negative organisms; however, the absence of lipopolysaccharide and 2-keto-3-deoxyoctonate in cell walls indicated that they are truly gram-positive organisms. They are unusual because peptidoglycan could not be detected during most of their growth cycle. The presence of lysine as the major diamino acid in cell wall hydrolysates, the inability to hydrolyze cellulose, and the distinctive developmental pattern with rods and “V” forms present during log phase, becoming progressively shorter until cocci dominated during stationary and death phases, indicated that these organisms belong to the genus
Arthrobacter
Conn and Dimmick. With the exception of the inability to hydrolyze gelatin, their characteristics are consistent with those of the type species,
Arthrobacter globiformis
Conn and Dimmick.