bluuebunny/crossref_metadata_2025 huggingface dataset:
Production and Fate of Methylated Sulfur Compounds from Methionine and Dimethylsulfoniopropionate in Anoxic Salt Marsh Sediments
Authors: Kiene Ronald P. , Visscher Pieter T.
Published: January 2020

Anoxic salt marsh sediments were amended with
dl
-methionine and dimethylsulfoniopropionate (DMSP). Microbial metabolism of methionine yielded methane thiol (MSH) as the major volatile organosulfur product, with the formation of lesser amounts of dimethylsulfide (DMS). Biological transformation of DMSP resulted in the rapid release of DMS and only small amounts of MSH. Experiments with microbial inhibitors indicated that production of MSH from methionine was carried out by procaryotic organisms, probably sulfate-reducing bacteria. Methane-producing bacteria did not metabolize methionine. The involvement of specific groups of organisms in DMSP hydrolysis could not be determined with the inhibitors used, because DMSP was hydrolyzed in all samples except those which were autoclaved. Unamended sediment slurries, prepared from
Spartina alterniflora
sediments, contained significant (1 to 10 μM) concentrations of DMS. Endogenous methylated sulfur compounds and those produced from added methionine and DMSP were consumed by sediment microbes. Both sulfate-reducing and methane-producing bacteria were involved in DMS and MSH consumption. Methanogenesis was stimulated by the volatile organosulfur compounds released from methionine and DMSP. However, apparent competition for these compounds exists between methanogens and sulfate reducers. At low (1 μM) concentrations of methionine, the terminal S-methyl group was metabolized almost exclusively to CO
2
and only small amounts of CH
4
. At higher (>100 μM) concentrations of methionine, the proportion of the methyl-sulfur group converted to CH
4
increased. The results of this study demonstrate that methionine and DMSP are potential precursors of methylated sulfur compounds in anoxic sediments and that the microbial community is capable of metabolizing volatile methylated sulfur compounds.
Construction of chlorobenzene-utilizing recombinants by progenitive manifestation of a rare event
Authors: Kr�ckel L , Focht D D
Published: January 2020

Separate continuous cultures of Pseudomonas putida R5-3, grown on toluene, and Pseudomonas alcaligenes C-O, grown on benzoate, were concentrated and continuously amalgamated on a ceramic bead column, which was subjected to a continuous stream of chlorobenzene vapors. A recombinant strain, P. putida CB1-9, was isolated in less than 1 month. P. alcaligenes C-0 grew on benzoate and 3-chlorobenzoate but not on toluene, P. putida R5-3 grew on benzoate and toluene but not on 3-chlorobenzoate, and neither strain grew on chlorobenzene or 1,4-dichlorobenzene; however, the recombinant P. putida CB1-9 grew on all of these substrates. Chlorobenzene-utilizing strains were not found in continuous cultures run at the lowest growth rate (0.05/h) or in the absence of the donor strain, P. alcaligenes C-0. Chloride was released in stoichiometric amounts when P. putida CB1-9 was grown on either chlorobenzene or 1,4-dichlorobenzene. The recombinant strain was related to P. putida R5-3, phenotypically and genetically. Restriction enzyme digests of the single 57-kilobase (kb) plasmid in R5-3 and of the single 33-kb plasmid in CB1-9 were similar, but also indicated rearrangement of plasmid DNA. Coincidental or causal to the loss of the 24-kb fragment was the observation that the recombinant--unlike its parent, R5-3--did not grow on xylenes or methylbenzoates. Although both ortho-pyrocatechase (OP) and meta-pyrocatechase (MP) were found in CB1-9 and R5-3, MP activity was 20- to 50-fold higher in R5-3 cells grown on 4-methylbenzoate than in the same cells grown on benzene.(ABSTRACT TRUNCATED AT 250 WORDS)
A Technique for Predicting the Solvent-Producing Ability of
Clostridium acetobutylicum
Authors: Adler Howard I. , Crow Weldon
Published: January 2020

Changes in colony morphology were associated with the degeneration of solvent-producing strains of
Clostridium acetobutylicum
. The most efficient solvent-producing strains gave rise exclusively to colonies with dense centers containing large numbers of spores. Many outgrowths of various morphologies developed from the perimeter of such colonies after several days of incubation. The most degenerate cultures did not produce solvents and gave rise to large diffuse colonies that did not contain spores. These diffuse colonies did not produce outgrowths. Intermediate colony types were also observed. These could be derived from liquid cultures that were relatively poor solvent producers or from the outgrowths of colonies of efficient solvent-producing strains. Some of these intermediate types produced spores but did so less frequently than the high-solvent-producing strains. The spores of the intermediate types could not be distinguished from those of the most efficient solvent producers on the basis of heat sensitivity. The relationship observed between colony morphology and solvent production provides a method for predicting the solvent-producing potential of
C. acetobutylicum
cultures.
Spontaneous Disaggregation of
Methanosarcina mazei
S-6 and Its Use in the Development of Genetic Techniques for
Methanosarcina
spp
Authors: Harris Jane E.
Published: January 2020

When monomethylamine was the growth substrate, spontaneous disaggregation of
Methanosarcina mazei
S-6 commenced at the mid-exponential phase and resulted in the formation of a suspension containing 10
8
to 10
9
free cells per ml. Free cells were osmotically fragile and amenable to extraction of DNA. Hypertonic media for the manipulation and regeneration of free cells into aggregates were developed, and plating efficiencies of 100% were achieved for
M. mazei
S-6 and LYC. Free cells of strain S-6 required MgCl
2
(10 mM) for growth, whereas aggregates did not. Specific growth rates of strains S-6 and LYC were increased by MgCl
2
. Treatment with pronase caused sphere formation and removal of the protein wall of cells of strain S-6, but protoplasts could not be regenerated. The disaggregating enzyme produced by strain S-6 facilitated the preparation of suspensions of free cells of some strains of
Methanosarcina barkeri
. Although this provided a means of extracting high-molecular-weight DNA from
M. barkeri
, less than 0.1% of free cells were viable.
Conserved Plasmid Hydrogen-Uptake (
hup
)-Specific Sequences within Hup
+
Rhizobium leguminosarum
Strains
Authors: Leyva Antonio , Palacios Jos� M. , Ruiz-Arg�eso Tom�s
Published: January 2020

Thirteen
Rhizobium leguminosarum
strains previously reported as H
2
-uptake hydrogenase positive (Hup
+
) or negative (Hup
−
) were analyzed for the presence and conservation of DNA sequences homologous to cloned
Bradyrhizobium japonicum hup
-specific DNA from cosmid pHU1 (M. A. Cantrell, R. A. Haugland, and H. J. Evans, Proc. Natl. Acad. Sci. USA 80:181-185, 1983). The Hup phenotype of these strains was reexamined by determining hydrogenase activity induced in bacteroids from pea nodules. Five strains, including H
2
oxidation-ATP synthesis-coupled and -uncoupled strains, induced significant rates of H
2
-uptake hydrogenase activity and contained DNA sequences homologous to three probe DNA fragments (5.9-kilobase [kb]
Hin
dIII, 2.9-kb
Eco
RI, and 5.0-kb
Eco
RI) from pHU1. The pattern of genomic DNA
Hin
dIII and
Eco
RI fragments with significant homology to each of the three probes was identical in all five strains regardless of the H
2
-dependent ATP generation trait. The restriction fragments containing the homology totalled about 22 kb of DNA common to the five strains. In all instances the putative
hup
sequences were located on a plasmid that also contained
nif
genes. The molecular sizes of the identified
hup-sym
plasmids ranged between 184 and 212 megadaltons. No common DNA sequences homologous to
B. japonicum hup
DNA were found in genomic DNA from any of the eight remaining strains showing no significant hydrogenase activity in pea bacteroids. These results suggest that the identified DNA region contains genes essential for hydrogenase activity in
R. leguminosarum
and that its organization is highly conserved within Hup
+
strains in this symbiotic species.
Flow microcalorimetry investigation of the influence of surfactants on a heterogeneous aerobic culture
Authors: Beaubien A , Keita L , Jolicoeur C
Published: January 2020

The influence of various surfactants on the biological activity of a mixed aerobic culture has been investigated by using flow microcalorimetry. The response of the culture to the addition of homologous n-alkylcarboxylates (C2 to C16) and n-alkylpyridinium bromides (C11 to C14) has been examined under endogenous and substrate saturation conditions, and inhibitory concentrations (MIC or the concentration which decreased the initial activity (heat flux) of the culture by 50%) were determined for each state. Under both conditions, the n-alkylpyridinium bromides were found to be more toxic than the n-alkylcarboxylates of identical chain length, thus confirming that the head group of the amphiphiles plays an important role in the microbial toxicity of surfactants. The relationship observed between the concentration at which 50% of the activity is lost and the chain length of the surfactant further confirms that cellular toxicity is also dependent on surfactant hydrophobicity. In relation to the biodegradability of surfactants in mixed aerobic cultures, the low concentration effects of n-alkylcarboxylates on endogenous culture were investigated in some detail. There appear to be compounded indications that these surfactants are rapidly metabolized by the microorganisms of the mixed culture, at least for homologs lower than C10.
Biogeochemical Conditions Favoring Magnetite Formation during Anaerobic Iron Reduction
Authors: Bell P. E. , Mills A. L. , Herman J. S.
Published: January 2020

Several anaerobic bacteria isolated from the sediments of Contrary Creek, an iron-rich environment, produced magnetite when cultured in combinations but not when cultured alone in synthetic iron oxyhydroxide medium. When glucose was added as a carbon source, the pH of the medium decreased (to 5.5) and no magnetite was formed. When the same growth medium without glucose was used, the pH increased (to 8.5) and magnetite was formed. In both cases, Fe
2+
was released into the growth medium. Geochemical equilibrium equations with E
h
and pH as master variables were solved for the concentrations of iron and inorganic carbon that were observed in the system. Magnetite was predicted to be the dominant iron oxide formed at high pHs, while free Fe
2+
or siderite were the dominant forms of iron expected at low pHs. Thus, magnetite formation occurs because of microbial alteration of the local E
h
and pH conditions, along with concurrent reduction of ferric iron (direct biological reduction or abiological oxidation-reduction reactions).
Methods for recovering poliovirus and rotavirus from oysters
Authors: Speirs J I , Pontefract R D , Harwig J
Published: January 2020

Polioviruses and rotaviruses are potential indicators of sewage pollution of water and shellfish. Several methods for detecting these viruses in oysters were assessed. Elution-precipitation involving Catfloc for clarification and skim milk for subsequent flocculation resulted in the recovery of an average of 79% of poliovirus type 1 and 37% of rotavirus SA-11 from oyster homogenates inoculated with low numbers of these viruses. Adsorption-elution-precipitation did not improve the recovery of poliovirus and was detrimental to the recovery of rotavirus. Ultrafiltration or ultracentrifugation resulted in improved recovery of rotavirus but also in higher toxicity of oyster extracts to cell cultures. We recommend the use of the described elution-precipitation method for detecting viral pollutants in sample of oysters.
Effects of Flow Cytometric Analysis on Morphology and Viability of Fragile Phytoplankton
Authors: Haugen Elin M. , Cucci Terry L. , Yentsch Clarice M. , Shapiro Lynda P.
Published: January 2020

We assessed damage done to especially delicate marine phytoplankton cells by passage through a Coulter Epics V flow cytometer. The cells did not distort or lyse after exposure to fluidics or to laser light to 1,000 mW. The cells did sustain damage evidenced by temporary growth rate depressions. The four clones tested eventually resumed control growth rates after growth lags to 48 h.
Conjugal transfer of plasmid pAM beta 1 in Lactobacillus reuteri and between lactobacilli and Enterococcus faecalis
Authors: Tannock G W
Published: January 2020

The broad-host-range plasmid pAM beta 1 (erythromycin resistance) was transferred conjugally from Streptococcus lactis to Lactobacillus reuteri, L. murinus, and L. fermentum. Transfer of pAM beta 1 between two L. reuteri strains occurred, and lactobacillus transconjugants could act as donors of pAM beta 1 in crosses with Enterococcus faecalis JH2-2.
Relative sensitivities of environmental legionellae to selective isolation procedures
Authors: Roberts K P , August C M , Nelson J D
Published: January 2020

A survey of water samples to determine the efficacy of standard procedures for the isolation of environmental legionellae was conducted. Marked variations in intraspecies resistance to selective agents and treatments were observed, and in experiments with one of the isolates, the response was modified by culture conditions. Five selective procedures incorporating acid (pH 2.2) and heat (50 degrees C, 30 min) treatments, with and without plating on buffered charcoal-yeast extract agar supplemented with vancomycin (5 micrograms/ml), polymyxin B (60 U/ml), and cycloheximide (80 micrograms/ml), caused 5 to 99% decreases in viable counts of pure cultures in water suspensions. The differences in the responses of the cultures to the five treatments were statistically significant. Cells in retained samples of naturally contaminated water from which the original cultures had been isolated were significantly less sensitive than artificially grown isolates. The sensitivities of the laboratory-grown cells to the treatments were affected by the length of incubation on buffered charcoal-yeast extract agar. Whereas acid resistance increased after 24 h of incubation, resistance to the antibiotic mixture decreased.
Isolation and characterization of a temperate bacteriophage from Streptomyces galilaeus
Authors: Kuhn S P , Lampel J S , Strohl W R
Published: January 2020

A new temperate actinophage from Streptomyces galilaeus ATCC 31133 was purified after that strain was crossed with S. peucetius ATCC 29050. Sensitive hosts became lysogenized and yielded turbid plaques of 2 to 3 mm in diameter. Host-range analysis indicated that 16 of 27 Streptomyces strains tested were sensitive to infection on solid medium. S. lividans and S. coelicolor A3(2) were among those not infected by this new actinophage. The new actinophage, designated phi SPK1, belongs to the Bradley group B morphological type, the pH optimum for infection is 6.75 to 7.0, it is not efficiently induced by mitomycin C or UV irradiation, it has a circular chromosome of 35.8 +/- 0.5 kilobase pairs in length containing overlapping (cohesive) ends, and the G+C content of its DNA was calculated from the buoyant density of 1.7240 to be 69 mol%. The DNA of phage phi SPK1 was cleaved by the restriction endonucleases ApaI, AluII, EcoRI, PvuII, and SalI, but, in all cases except that with EcoRI, treatment yielded greater than 20 restriction fragments. No sites were detected for BamHI, BclI, BglII, ClaI, HindIII, MluI, PstI, SmaI, SphI, SstI, XbaI, or XhoI.
Examination and characterization of distribution system biofilms
Authors: LeChevallier M W , Babcock T M , Lee R G
Published: January 2020

Investigations concerning the role of distribution system biofilms on water quality were conducted at a drinking water utility in New Jersey. The utility experienced long-term bacteriological problems in the distribution system, while treatment plant effluents were uniformly negative for coliform bacteria. Results of a monitoring program showed increased coliform levels as the water moved from the treatment plant through the distribution system. Increased coliform densities could not be accounted for by growth of the cells in the water column alone. Identification of coliform bacteria showed that species diversity increased as water flowed through the study area. All materials in the distribution system had high densities of heterotrophic plate count bacteria, while high levels of coliforms were detected only in iron tubercles. Coliform bacteria with the same biochemical profile were found both in distribution system biofilms and in the water column. Assimilable organic carbon determinations showed that carbon levels declined as water flowed through the study area. Maintenance of a 1.0-mg/liter free chlorine residual was insufficient to control coliform occurrences. Flushing and pigging the study area was not an effective control for coliform occurrences in that section. Because coliform bacteria growing in distribution system biofilms may mask the presence of indicator organisms resulting from a true breakdown of treatment barriers, the report recommends that efforts continue to find methods to control growth of coliform bacteria in pipeline biofilms.
Genetic and physical characterization of proBA genes of the marine bacterium Vibrio parahaemolyticus
Authors: Datta A R , Ostroff R , MacQuillan A M
Published: January 2020

Intracellular proline pools have been implicated in the halotolerance of many organisms. To examine this relationship in a moderately halotolerant marine bacterium, Vibrio parahaemolyticus, proline biosynthesis genes were cloned in various plasmids. Some genetic and structural properties of those genes were examined. Subcloning showed that about 3.1 kilobases of V. parahaemolyticus DNA could complement proA and proB but not proC mutations of Escherichia coli. The same fragment would also complement some Pro- mutants of V. parahaemolyticus. Gamma-delta insertion mutagenesis of this subcloned fragment indicated that proB and proA genes of V. parahaemolyticus might be transcribed from different promoters. Two other genes, phoE and gpt, which map closely to the proBA genes in E. coli, were also found to be in close proximity to the proBA genes of V. parahaemolyticus.
Annual Cycle of Bacterial Specific Biovolumes in Howe Sound, a Canadian West Coast Fjord Sound
Authors: Albright L. J. , McCrae S. K.
Published: January 2020

The mean specific biovolumes (biovolume cell
−1
) of the bacterioplankton within a 250-m-deep water column in Howe Sound, British Columbia, were determined for the period of 4 September 1984 to 23 October 1985. These bacteria had an annual cycle in mean specific biovolume; they were small (ca. 0.058 μm
3
) in mid-winter, larger in spring (ca. 0.076 μm
3
), larger again in summer (up to 0.102 μm
3
), and largest (ca. 0.133 μm
3
) in early fall (immediately after the decrease in phytoplankton production). The mean specific biovolumes changed coincidently through the water column with time, although the larger bacterioplankton tended to occur in the surface and deepest water. Although the mean specific biovolumes correlated better with in situ temperature (
r
= 0.65,
a
= 0.01) than with in situ chlorophyll
a
concentration (
r
= 0.34,
a
= 0.25), modeling experiments with batch cultures of the dinoflagellate
Prorocentrum minimum
(Pavillard) and the green alga
Dunaliella tertiolecta
(Butcher) indicated that the biomass and physiological condition of the phytoplankters may be more important than temperature in determining these bacterial specific biovolumes.
Effects of Temperature and pH on Survival of Free Nuclear Polyhedrosis Virus of
Autographa californica
Authors: Knittel M. D. , Fairbrother Anne
Published: January 2020

The effects of temperature and low pH on replication and survival of nonoccluded
Autographa californica
nuclear polyhedrosis virus were investigated. No virus replication or formation of polynuclear inclusion bodies occurred at 37°C. The virus was immediately inactivated upon exposure to pH 2.0 and was inactivated within 1 h at pH 4.0. The virus titer slowly declined, a 3-orders of magnitude reduction in virus titer, at pH 5.0 during a 4-h exposure. Virus survival at pH 6.0 was equal to that of the control in cell culture medium 199 MK (pH 7.12).
Qualitative assessment of vaginal microflora during use of tampons of various compositions
Authors: Onderdonk A B , Zamarchi G R , Rodriguez M L , Hirsch M L , Muñoz A , Kass E H
Published: January 2020

The effect of vaginal tampons on the microbial flora during menstruation has recently been studied by several investigators. However, little information regarding the qualitative effects attributable to particular tampon fibers is available. The purpose of the present study was to compare the effects of polyacrylate rayon tampons and cotton-viscose rayon blend tampons on the qualitative bacterial counts obtained from tampons and concomitant vaginal swabs and to determine whether either of these tampon types alters the qualitative makeup of the vaginal microflora when compared with the microflora in the same women using all-cotton tampons or external catamenial pads. Tampon and swab samples were obtained as described previously (A. B. Onderdonk, G. R. Zamarchi, M. L. Rodriguez, M. L. Hirsch, A. Muñoz, and E. H. Kass, Appl. Environ. Microbiol. 53:2774-2778). The genus and species of the six dominant bacterial species in each sample were identified, if possible. A statistical evaluation of the qualitative makeup of the microflora revealed that the same numerically dominant phenotypes were present regardless of sample type, sample time, or catamenial product. Predictable changes in total numbers among the dominant species were also noted when the data were evaluated by day of menstrual cycle. The correlation between the total numbers of each dominant species present was evaluated by day of cycle, and the findings are discussed.
Macromolecular Organization of the Cellulolytic Enzyme Complex of
Clostridium thermocellum
as Revealed by Electron Microscopy
Authors: Mayer Frank , Coughlan Michael P. , Mori Yutaka , Ljungdahl Lars G.
Published: January 2020

Clostridium thermocellum
JW20 and YM4 both synthesize cellulolytic enzyme complexes, cellulosomes, when grown on medium containing cellulose. Electron microscopic studies showed that, in the early stages of growth of strain JW20, clusters of tightly packed cellulosomes, i.e., polycellulosomes, were located on the cell surface and were bound to cellulose. The polycellulosome was estimated to have a particle mass of 50 × 10
6
to 80 × 10
6
daltons (Da), while that of the cellulosome was estimated to be 2 × 10
6
to 2.5 × 10
6
Da and to contain about 35 polypeptides ranging from 20 to 200 kDa. The cellulosome produced by strain YM4 was found to be somewhat larger, with the estimated particle mass being 3.5 × 10
6
Da, and the number of polypeptides was counted to be 45 to 50, ranging from 20 to 200 kDa. In the early stages of cultivation, the cellulosomes from both species exist as tightly packed complexes (tight cellulosomes). These subsequently decompose to loosely packed complexes (loose cellulosomes) and ultimately to free polypeptides. Examination of the loose cellulosomal particles showed that they contain rows of equidistantly spaced, similarly sized polypeptide subunits, with an apparently identical orientation arranged parallel to the major axis of the cellulosome. It is postulated that on binding of a cellulose chain alongside such a row of subunits a simultaneous multicutting event occurs that leads to the release of cellooligosaccharides of four cellobiose units in length (C
4
). Rows of smaller-sized subunits with lower center-to-center distances, which are also present in the cellulosome, subsequently cleave the C
4
fragments (or cellulose) to C
2
(cellotetraose) or C
1
(cellobiose). In this way the cellulosome can catalyze the complete hydrolysis of cellulose.
Conversion of a new metabolite to aflatoxin B2 by Aspergillus parasiticus
Authors: Cleveland T E , Bhatnagar D , Foell C J , McCormick S P
Published: January 2020

A new metabolite which could be converted to aflatoxin (AF) B2 was detected during cofermentation analysis of two nonaflatoxigenic strains (SRRC 2043 and SRRC 163) of Aspergillus parasiticus. SRRC 2043, which accumulates the xanthone O-methylsterigmatocystin (OMST), a late precursor in the AFB1 pathway, was observed to accumulate another chemically related compound (HOMST; molecular weight, 356); SRRC 163 is blocked early in the pathway and accumulates averantin. During cofermentation of the two strains, levels of OMST and HOMST were observed to be greatly reduced in the culture, with simultaneous production of AFB1, AFB2, and AFG1. Intact cells of SRRC 163 were able to convert pure OMST or its precursor, sterigmatocystin, to AFB1 and AFG1 without AFB2 accumulation; the same cells converted isolated HOMST to AFB2 with no AFB1 or AFG1 production. The results indicate that AFB2 is produced from a separate branch in the AF biosynthetic pathway than are AFB1 and AFG1; AFB2 arises from HOMST, and AFB1 and AFG1 arise from sterigmatocystin and OMST.
Production of Acetaldehyde by
Zymomonas mobilis
Authors: Wecker Matt S. A. , Zall Robert R.
Published: January 2020

Mutants of
Zymomonas mobilis
were selected for decreased alcohol dehydrogenase activity by using consecutively higher concentrations of allyl alcohol. A mutant selected by using 100 mM allyl alcohol produced acetaldehyde at a level of 4.08 g/liter when the organism was grown in aerated batch cultures on a medium containing 4.0% (wt/wt) glucose. On the basis of the amount of glucose utilized, this level of acetaldehyde production represents nearly 40% of the maximum theoretical yield. Acetaldehyde produced during growth was continuously air stripped from the reactor. Acetaldehyde present in the exhaust stream was then trapped as the acetaldehyde-bisulfite addition product in an aqueous solution of sodium bisulfite and released by treatment with base. Acetaldehyde was found to inhibit growth of
Z. mobilis
at concentrations as low as 0.05% (wt/wt) acetaldehyde. An acetaldehyde-tolerant mutant of
Z. mobilis
was isolated after both mutagenesis with nitrosoguanidine and selection in the presence of vapor-phase acetaldehyde. The production of acetaldehyde has potential advantages over that of ethanol: lower energy requirements for product separation, efficient separation of product from dilute feed streams, continuous separation of product from the reactor, and a higher marketplace value.
Metabolic activity of bacterial cells enumerated by direct viable count
Authors: Roszak D B , Colwell R R
Published: January 2020

The direct viable count (DVC) method was modified by incorporating radiolabeled substrates in microautoradiographic analyses to assess bacterial survival in controlled laboratory microcosms. The DVC method, which permits enumeration of culturable and nonculturable cells, discriminates those cells that are responsive to added nutrients but in which division is inhibited by the addition of nalidixic acid. The resulting elongated cells represent all viable cells; this includes those that are culturable on routine media and those that are not. Escherichia coli and Salmonella enteritidis were employed in the microcosm studies, and radiolabeled substrates included [methyl-3H]thymidine or [U-14C]glutamic acid. Samples taken at selected intervals during the survival experiments were examined by epifluorescence microscopy to enumerate cells by the DVC and acridine orange direct count methods, as well as by culture methods. Good correlation was obtained for cell-associated metabolic activity, measured by microautoradiography and substrate responsiveness (by the DVC method) at various stages of survival. Of the cells responsive to nutrients by the DVC method, ca. 90% were metabolically active by the microautoradiographic method. No significant difference was observed between DVC enumerations with or without added radiolabeled substrate.
Recovery of a marker strain of Escherichia coli from ozonated water by membrane filtration
Authors: Finch G R , Stiles M E , Smith D W
Published: January 2020

Selective and nonselective growth media were evaluated at two incubation temperatures, 35 and 44.5 degrees C, for the recovery of a nalidixic acid-resistant marker strain of Escherichia coli ATCC 11775 by membrane filtration from ozonated 0.05 M phosphate buffer (pH 6.9). There were significantly fewer bacteria recovered with the standard m-FC agar when compared with the same growth medium prepared without bile salts and rosolic acid. This effect was particularly noticeable at the elevated incubation temperature of 44.5 degrees C. These findings are contrary to previous work which concluded that the standard American Public Health Association membrane filtration procedure is suitable for recovery of fecal coliform indicator bacteria from ozonated wastewater.
Oxidation of Gaseous and Volatile Hydrocarbons by Selected Alkene-Utilizing Bacteria
Authors: van Ginkel C. G. , Welten H. G. J. , de Bont J. A. M.
Published: January 2020

Eleven strains of alkene-utilizing bacteria belonging to the genera
Mycobacterium, Nocardia,
and
Xanthobacter
were tested for their ability to grow with C
1
to C
6
alkanes, C
2
to C
6
alkenes, alkadienes, and monoterpenes furnished individually as sole sources of carbon and energy in a mineral salts medium. A limited number of alkenes and alkanes supported growth of the bacteria; some bacteria were unable to grow on any of the saturated hydrocarbons tested. Monoterpenes were frequently used as carbon and energy sources by alkene-utilizing bacteria belonging to the genera
Mycobacterium
and
Nocardia.
Washed cell suspensions of alkene-grown bacteria attacked the whole range of alkenes tested, whereas only three strains were able to oxidize alkanes as well. The alkenes tested were oxidized either to water and carbon dioxide or to epoxyalkanes. Few epoxides accumulated in stoichiometric amounts from the corresponding alkenes, because most epoxides formed were further converted to other compounds like alkanediols.
Chelating Properties of Extracellular Polysaccharides from
Chlorella
spp
Authors: Kaplan Drora , Christiaen Daniel , Arad Shoshana (Malis)
Published: January 2020

Chlorella stigmatophora
LB 993 was grown in artificial seawater under controlled conditions. The production of cell wall polysaccharides attached to the cells and dissolved in the growth medium was monitored during algal growth. Preliminary characterization of the dissolved polysaccharides of
C. stigmatophora
and other
Chlorella
species is presented. The capacity of dissolved polysaccharides of
C. stigmatophora
to bind toxic heavy metals was also studied and compared with that of polysaccharides produced by other marine
Chlorella
species. The differences in metal-complexing capacity observed for dissolved polysaccharides obtained from various
Chlorella
species is attributable to differences in the composition of the polysaccharides, notably the uronic acids content.
Distribution and significance of heterotrophic marine bacteria with antibacterial activity
Authors: Nair S , Simidu U
Published: January 2020

Bacteria with antibacterial activity were isolated from seawater, sediments, phytoplankton, and zooplankton of Suruga, Sagami, and Tokyo Bays and from soft corals and sponges collected from the Taiwan coast. Of the 726 strains isolated, 37 showed antibacterial activity against either Vibrio parahaemolyticus (ATCC 17802) or Staphylococcus aureus (P209). Sediment harbored the lowest number of these forms of bacteria, and those from Tokyo Bay did not show any activity. Attached isolates showed greater activity compared with free-living forms. Relatively high numbers of strains with antibacterial activity were associated with phytoplankton. Among the zooplankton isolates, cladocerans harbored the maximum number of antibacterial strains. Isolates were more inhibitory to gram-positive test cultures. Autoinhibition was observed only among 8% of the isolates. Marine nonproducers were more susceptible. Pseudomonas/Alteromonas species made up 81.0% of isolates, of which 30% were pigmented strains. The absence or reduction in number of bacteria with antibacterial activity in Tokyo Bay is attributed to its eutrophic nature, which may tend to moderate the production of antibacterial compounds.
Characteristics of Cyclic AMP Transport by Marine Bacteria
Authors: Ammerman James W. , Azam Farooq
Published: January 2020

Uptake and autoradiography experiments with natural populations of marine bacteria, seawater cultures, and cultured isolates showed that the high-affinity cyclic AMP transport system in marine bacteria has stringent structural requirements, is found in a minority of cells in mixed bacterial assemblages, and appears to be related to the culture growth state.
Production of cytopathology in FRhK-4 cells by BS-C-1-passaged hepatitis A virus
Authors: Nasser A M , Metcalf T G
Published: January 2020

Cytopathic effects were produced in fetal rhesus monkey kidney (FRhK-4) cells 7 days postinfection by a serially BS-C-1-passaged strain of hepatitis A virus. Typical enterovirus cytopathology was produced by the HM-175 strain after 15 passages at 7-day intervals in BS-C-1 cells. No cytopathic effects were obtained after neutralization of virus with human anti-hepatitis A virus immunoglobulin G. Normal human serum had no effect on development of cytopathology. Maximum antigen and cDNA probe-based hybridization activity were associated with a CsCl gradient fraction having a density of 1.34 g/cm3. Large quantities of 27- to 30-nm virions typical of hepatitis A virus were associated with the same fraction. These data led to the conclusion that the observed cytopathology was caused by hepatitis A virus.
Factors Affecting the Methanogenic Activity of
Methanothrix soehngenii
VNBF
Authors: Fathepure Babu Z.
Published: January 2020

Methane production by
Methanothrix soehngenii
VNBF grown on acetate (50 mM) as the sole carbon and energy source was influenced by the addition of Fe, trace elements, and pesticides. The addition of Fe and trace elements significantly enhanced the rate of CH
4
production. The addition of pesticides in the early growth phase caused complete inhibition. However, less inhibition was noted when pesticides were added during early exponential growth phase. Addition to culture tubes of Co, Ni, or Mo at 2 μM produced 64, 41, or 17%, respectively, more CH
4
than that produced in tubes lacking the corresponding trace element. A concentration of more than 5 μM of these trace elements in the medium resulted in decreased CH
4
production, presumably because of toxic effects.
Properties of Lactose Plasmid pLY101 in
Lactobacillus casei
Authors: Shimizu-Kadota Mariko
Published: January 2020

A starter strain,
Lactobacillus casei
C257, was found to carry a lactose plasmid, pLY101. Restriction mapping showed that pLY101 DNA was 68.2 kilobases long. Since a non-lactose-utilizing variant of C257, MSK248, lost phospho-β-galactosidase (P-β-gal) activity and pLY101 DNA had a sequence(s) homologous to the streptococcal fragment including a P-β-gal gene, pLY101 is likely to encode a P-β-gal gene required for lactose metabolism in C257. MSK248 grew in galactose medium at a rate identical to that of C257 and retained phosphoenolpyruvate-dependent phosphotransferase system activity for lactose similar to that of C257. Therefore, the C257 chromosome appears to encode a complete set of genes for the lactose-phosphotransferase system and the predominant galactose metabolic pathway in C257. pLY101 DNA had a sequence homologous to a lactobacillus insertion sequence, ISL
1
, which mapped more than 12 kilobases from the sequence homologous to the streptococcal P-β-gal fragment.
Metabolism of alkyl amines by the filamentous fungus Aspergillus versicolor
Authors: Lindley N D
Published: January 2020

A variety of monoalkyl-substituted amines were able to act as nitrogen sources for heterotrophically growing cultures of Aspergillus versicolor. Only amines whose alkyl chains were at least five carbon atoms long were capable of supporting significant growth in the absence of a separate carbon substrate. However, biomass yields were significantly higher during growth on glucose-amine than on glucose-ammonia, indicating that some energy-generating dissimilation of the amine to CO2 took place.
Penicillium viridicatum, Penicillium verrucosum, and production of ochratoxin A
Authors: Pitt J I
Published: January 2020

The taxonomy of the important mycotoxigenic species Penicillium viridicatum and P. verrucosum was reviewed to clarify disagreements relating to the three P. viridicatum groups erected by Ciegler and coworkers (A. Ciegler, D. I. Fennell, G. A. Sansing, R. W. Detroy, and G. A. Bennett, Appl. Microbiol. 26:271-278, 1973) and the mycotoxins produced by them. Cultures derived from the types of these two species and authentic cultures from each group and from many other sources were examined culturally, microscopically, and for mycotoxin production. It was concluded that P. viridicatum group II has affinities with P. verrucosum and not with P. viridicatum, as indicated by J. I. Pitt in the 1979 monograph (The Genus Penicillium and Its Teleomorphic States Eupenicillium and Talaromyces). As a result of this study it can now be unequivocally stated that the mycotoxins ochratoxin A and citrinin are not produced by P. viridicatum. Of species in subgenus Penicillium, only P. verrucosum is known to produce ochratoxin A.
Quantification and Removal of Some Contaminating Gases from Acetylene Used to Study Gas-Utilizing Enzymes and Microorganisms
Authors: Hyman Michael R. , Arp Daniel J.
Published: January 2020

Acetylene generated from various grades of calcium carbide and obtained from commercial- and purified-grade acetylene cylinders was shown to contain high concentrations of various contaminants. Dependent on the source of acetylene, these included, at maximal values, H
2
(0.023%), O
2
(0.779%), N
2
(3.78%), PH
3
(0.06%), CH
4
(0.073%), and acetone (1 to 10%). The concentration of the contaminants in cylinder acetylene was highly dependent on the extent of cylinder discharge. Several conventional methods used to partially purify cylinder acetylene were compared. A small-scale method for extensively purifying acetylene is described. An effect of acetylene quality on acetylene reduction assays conducted with purified nitrogenase from
Azotobacter vinelandii
was demonstrated.
Bacterial Communities in Acidic and Circumneutral Streams
Authors: Palumbo Anthony V. , Bogle Mary Anna , Turner Ralph R. , Elwood Jerry W. , Mulholland Patrick J.
Published: January 2020

The relationship between pH and the abundance and activity of bacteria in streams was examined as part of a study of the effect of acidification on stream communities. Of the bacterial communities examined, the epilithic community appeared to be the most significantly affected by acidification. Microbial biomass, as quantified by measuring the ATP level, on rock surfaces was significantly correlated with pH. Also, bacterial production by the epilithic bacteria, indicated by incorporation of tritiated thymidine into DNA, was always higher at high-pH sites than at low-pH sites of the same stream order and elevation. Bacterioplankton concentrations varied between 0.53 × 10
5
and 9.42 × 10
5
cells · ml
−1
in the first- to fourth-order streams examined. The bacterioplankton concentration in one sample from a spring was 0.17 × 10
5
cells · ml
−1
. Bacterioplankton concentrations were not correlated with pH but were significantly correlated with seston concentrations. The correlation with seston is a result of increases in particle-associated bacteria at high seston concentrations. The proportion of bacterioplankton attached to particles varied from 0 to 70%. Bacterial numbers and production in the sediments were significantly correlated with the organic content of the sediment rather than with the pH of the overlying water. Thus, reduced abundance and activity of bacteria as a result of acidification could be detected only for the relatively active community on rock surfaces; this community was exposed to the low pH because of the unbuffered nature of its environment.
Conjugal transfer of nisin plasmid genes from Streptococcus lactis 7962 to Leuconostoc dextranicum 181
Authors: Tsai H J , Sandine W E
Published: January 2020

Acriflavine-generated mutants of Streptococcus lactis 7962 with various combinations of plasmid molecular masses were screened for nisin production. Nisin was produced by both the wild type and mutants that contained a 17.5-megadalton plasmid, which was obscured by chromosomal fragments. No nisin was produced by plasmid-free mutants. Sucrose fermentation and nisin production were simultaneously expressed. A transconjugant obtained from nisin-producing donor S. lactis 7962 and recipient Leuconostoc dextranicum 181 was a "supernisin" producer. The L. dextranicum Nis+ transconjugant was resistant to S. lactis 7962 phage and vancomycin (greater than 1,000 micrograms/ml), and it contained an extra 17.5-megadalton plasmid.
Protease-deficient Bacillus subtilis host strains for production of Staphylococcal protein A
Authors: Fahnestock S R , Fisher K E
Published: January 2020

We constructed strains of Bacillus subtilis which produced very low levels of extracellular proteases. These strains carried insertion or deletion mutations in the subtilisin structural gene (apr) which were constructed in vitro by using the cloned gene. The methods used to construct the mutations involved the use of a plasmid vector which allowed the selection of chromosomal integrates and their subsequent excision by homologous recombination to effect replacement of the chromosomal apr gene by a derivative carrying an inactivating insert with a selectable marker (a cat gene conferring chloramphenicol resistance). The strains produced no subtilisin, no detectable extracellular metalloprotease activity, and residual extracellular serine protease levels as low as 0.5% of that of the standard strain from which they were derived. The strains proved to be superior host strains for the production of staphylococcal protein A, accumulating higher levels of intact protein than do previously available B. subtilis strains.
Bacteriophage Resistance Plasmid pTR2030 Inhibits Lytic Infection of r
1
t Temperate Bacteriophage but Not Induction of r
1
t Prophage in
Streptococcus cremoris
R1
Authors: Jarvis Audrey W. , Klaenhammer Todd R.
Published: January 2020

The effects of pTR2030 on the replication of four small isometric bacteriophages were examined in
Streptococcus cremoris
R1. Three lytic phages (652, 720, and 751), which were isolated independently over a 29-year period, were unable to form plaques on a pTR2030 transconjugant of
S. cremoris
R1. The fourth phage evaluated, phage r
1
t, was a temperate phage induced from
S. cremoris
R1 by treatment with mitomycin C. A prophage-cured derivative of
S. cremoris
R1, designated R1Cs, was isolated and served as a lytic indicator for phage r
1
t. Strain R1Cs and a derivative of this strain that was relysogenized with r
1
t, designated R1Cs(r
1
t), were used as conjugal recipients for transfer of the phage resistance plasmid pTR2030. pTR2030 transconjugants of strains R1Cs and R1Cs(r
1
t) were evaluated for sensitivity to r
1
t phage and induction of r
1
t prophage, respectively. The temperate phage r
1
t adsorbed eficiently but did not form plaques on the prophage-cured, pTR2030 transconjugant strain T-R1Cs. However, in the r
1
t lysogen [T-R1Cs(r
1
t)], pTR2030 did not inhibit prophage induction with mitomycin C, cell lysis, or production of infective r
1
t phage particles. The data demonstrated that pTR2030-induced resistance inhibited lytic infection by r
1
t phage from without but did not retard lytic development after prophage induction within the cell. It was suggested that pTR2030-encoded phage resistance to small isometric phages may, therefore, act at the cell surface or membrane to prevent phage DNA passage into the host cell or inhibit early events required for lytic replication of externally infecting phage.
Thermophilic Anaerobic Degradation of Butyrate by a Butyrate-Utilizing Bacterium in Coculture and Triculture with Methanogenic Bacteria
Authors: Ahring Birgitte K. , Westermann Peter
Published: January 2020

We studied syntrophic butyrate degradation in thermophilic mixed cultures containing a butyrate-degrading bacterium isolated in coculture with
Methanobacterium thermoautotrophicum
or in triculture with
M. thermoautotrophicum
and the TAM organism, a thermophilic acetate-utilizing methanogenic bacterium. Butyrate was β-oxidized to acetate with protons as the electron acceptors. Acetate was used concurrently with its production in the triculture. We found a higher butyrate degradation rate in the triculture, in which both hydrogen and acetate were utilized, than in the coculture, in which acetate accumulated. Yeast extract, rumen fluid, and clarified digestor fluid stimulated butyrate degradation, while the effect of Trypticase was less pronounced. Penicillin G,
d
-cycloserine, and vancomycin caused complete inhibition of butyrate utilization by the cultures. No growth or degradation of butyrate occurred when 2-bromoethanesulfonic acid or chloroform, specific inhibitors of methanogenic bacteria, was added to the cultures and common electron acceptors such as sulfate, nitrate, and fumarate were not used with butyrate as the electron donor. Addition of hydrogen or oxygen to the gas phase immediately stopped growth and butyrate degradation by the cultures. Butyrate was, however, metabolized at approximately the same rate when hydrogen was removed from the cultures and was metabolized at a reduced rate in the cultures previously exposed to hydrogen.
Salt tolerance of lactose-grown Vibrio parahaemolyticus carrying Escherichia coli lac genes
Authors: Datta A R , MacQuillan A M
Published: January 2020

Lac- strains of Vibrio parahaemolyticus were converted to Lac+ on receiving a hybrid plasmid containing the lactose utilization genes of Escherichia coli K-12. A V. parahaemolyticus strain containing this hybrid plasmid exhibited optimal growth rates on glucose and other carbon sources in the presence of 0.2 to 0.4 M NaCl. Growth of the same strain on lactose was inhibited at similar concentrations of NaCl. The altered growth rate responses in lactose medium appeared to be attributable to effects of NaCl on the activity of lactose permease, and possibly on that of beta-galactosidase, rather than on the levels of these enzymes in V. parahaemolyticus cells.