bluuebunny/crossref_metadata_2025 huggingface dataset:
The K1 Toxin of
Saccharomyces cerevisiae
Kills Spheroplasts of Many Yeast Species
Authors: Zhu Hong , Bussey Howard
Published: January 2020

The
Saccharomyces cerevisiae
K1 toxin killed spheroplasts from the genera
Candida, Kluyveromyces
, and
Schwanniomyces.
Cells of these organisms were toxin insensitive. The toxin bound poorly to
Kluyveromyces lactis
cells. In contrast,
Candida albicans
bound the toxin to an extent similar to that seen with
S. cerevisiae.
Thus, wall receptors can define toxin specificity and are necessary but not sufficient for toxin action on intact cells.
Degradation of pentachlorophenol by polyurethane-immobilized Flavobacterium cells
Authors: O'Reilly K T , Crawford R L
Published: January 2020

Polyurethane-immobilized Flavobacterium cells (ATCC 39723) degraded pentachlorophenol (PCP) at initial concentrations as high as 300 mg liter-1. The reversible binding of PCP to the polyurethane was shown to be important in the protection of the cells from inhibition of PCP degradation. The degradation activity of the bacteria was monitored for 150 days in semicontinuous batch reactors. The degradation rate dropped by about 0.6% per day. PCP was degraded in a continuous-culture bioreactor at a rate of 3.5 to 4 mg g of foam-1 day-1 for 25 days. Electron micrographs of the polyurethane suggested that the cells were entrapped within 50- to 500-microns-diameter pockets in the foam.
Continuous-Culture Responses of
Candida shehatae
to Shifts in Temperature and Aeration: Implications for Ethanol Inhibition
Authors: Alexander M. A. , Chapman T. W. , Jeffries T. W.
Published: January 2020

Temperature and aeration shifts were used to perturb steady-state continuous cultures to determine the effects of ethanol on xylose metabolism by
Candida shehatae.
The accumulation of ethanol exerted a delayed inhibitory effect on the specific rate of substrate utilization. A second effect was also observed in which the specific rate of xylitol production increased at the expense of the specific rate of ethanol production. Both effects were enhanced at higher temperature. Inhibitory effects also occurred in glucose metabolism.
Physiological, chemical, morphological, and plant infectivity characteristics of Frankia isolates from Myrica pennsylvanica: correlation to DNA restriction patterns
Authors: Bloom R A , Lechevalier M P , Tate R L
Published: January 2020

The filter exclusion method was used to isolate Frankia strains from Myrica pennsylvanica (bayberry) root nodules collected at diverse sites in New Jersey. A total of 16 isolates from five locations were cultured. The isolates were characterized by morphological, chemical, physiological, and plant infectivity criteria and compared with genomic DNA restriction pattern data, which were used to assign the isolates into gel groups (see accompanying paper). The isolates from M. pennsylvanica evaluated in this study were characteristic of Frankia physiological group B strains and were indistinguishable on the basis of whole-cell wall chemistry and diaminopimelic acid isomer analysis. Distinct differences in the spectrum of utilized organic acids and carbohydrates were observed among the isolates and were the only phenotypic criteria by which the isolates could be separated and assigned into separate groups. In general, isolates within a restriction pattern gel group had identical utilization patterns, whereas intragroup isolates had different utilization patterns. Correlation of these phenotypic characteristics with the results of molecular analysis revealed an exclusive carbohydrate and organic acid utilization pattern for each gel group as established by restriction pattern analysis.
Bacterial secondary production on vascular plant detritus: relationships to detritus composition and degradation rate
Authors: Moran M A , Hodson R E
Published: January 2020

Bacterial production at the expense of vascular plant detritus was measured for three emergent plant species (Juncus effusus, Panicum hemitomon, and Typha latifolia) degrading in the littoral zone of a thermally impacted lake. Bacterial secondary production, measured as tritiated thymidine incorporation into DNA, ranged from 0.01 to 0.81 microgram of bacterial C mg of detritus-1 day-1. The three plant species differed with respect to the amount of bacterial productivity they supported per milligram of detritus, in accordance with the predicted biodegradability of the plant material based on initial nitrogen content, lignin content, and C/N ratio. Bacterial production also varied throughout the 22 weeks of in situ decomposition and was positively related to the nitrogen content and lignin content of the remaining detritus, as well as to the temperature of the lake water. Over time, production was negatively related to the C/N ratio and cellulose content of the degrading plant material. Bacterial production on degrading plant material was also calculated on the basis of plant surface area and ranged from 0.17 to 1.98 micrograms of bacterial C cm-2 day-1. Surface area-based calculations did not correlate well with either initial plant composition or changing composition of the remaining detritus during decomposition. The rate of bacterial detritus degradation, calculated from measured production of surface-attached bacteria, was much lower than the actual rate of weight loss of plant material. This discrepancy may be attributable to the importance of nonbacterial organisms in the degradation and loss of plant material from litterbags or to the microbially mediated solubilization of particulate material prior to bacterial utilization, or both.
Characterization of the temperate bacteriophage phi adh and plasmid transduction in Lactobacillus acidophilus ADH
Authors: Raya R R , Kleeman E G , Luchansky J B , Klaenhammer T R
Published: January 2020

Lactobacillus acidophilus ADH is lysogenic and harbors an inducible prophage, phi adh. Bacteriophage were detected in cell lysates induced by treatment with mitomycin C or UV light. Electron microscopy of lysates revealed phage particles with a hexagonal head (62 nm) and a long, noncontractile, flexible tail (398 nm) ending in at last five short fibers. Phage phi adh was classified within Bradley's B1 phage group and the Siphoviridae family. The phi adh genome is a linear double-stranded DNA molecule of 41.7 kilobase pairs with cohesive ends: a physical map of the phi adh genome was constructed. A prophage-cured derivative of strain ADH, designated NCK102, was isolated from cells that survived UV exposure. NCK102 did not exhibit mitomycin C-induced lysis, but broth cultures lysed upon addition of phage. Phage phi adh produced clear plaques on NCK102 in media containing 10 mM CaCl2 at pH values between 5.2 and 5.5. A relysogenized derivative (NCK103) of NCK102 was isolated that exhibited mitomycin C-induced lysis and superinfection immunity to phage phi adh. Hybridization experiments showed that the phi adh genome was present in the ADH and NCK103 chromosomes, but absent in NCK102. These results demonstrated classic lytic and lysogenic cycles of replication for the temperate phage phi adh induced from L. acidophilus ADH. Phage phi adh also mediates transduction of plasmid DNA. Transductants of strain ADH containing pC194, pGK12, pGB354, and pVA797 were detected at frequencies in the range of 3.6 x 10(-8) to 8.3 x 10(-10) per PFU. Rearrangements or deletions were not detected in these plasmids as a consequence of transduction. This is the first description of plasmid transduction in the genus Lactobacillus.
Cloning of a gene encoding a major secreted polypeptide of Listeria monocytogenes and its potential use as a species-specific probe
Authors: Flamm R K , Hinrichs D J , Thomashow M F
Published: January 2020

A gene, designated msp, that encodes a major secreted polypeptide with a molecular mass of approximately 60 kilodaltons (kDa) was cloned from Listeria monocytogenes 10403. DNA hybridization analysis indicated that the msp gene was highly conserved among 15 independent L. monocytogenes isolates and that each of 5 isolates tested secreted a 60-kDa polypeptide that was immunologically related to the msp gene product. DNA sequences related to msp were not detected in any other Listeria species or in strains of Bacillus cereus, Bacillus thuringiensis, Streptococcus pyogenes, or Streptococcus pneumoniae when standard stringent DNA hybridization conditions were used. Under nonstringent conditions, related sequences were detected in Listeria ivanovii, Listeria seeligeri, and Listeria innocua, and immunoblot analysis indicated that these strains secreted polypeptides of about 60 kDa that were immunologically related to the msp gene product. The possibility of using the msp gene as a probe for the detection of L. monocytogenes and the potential functions of the msp gene product are discussed.
Degradation of Acetonitrile by
Pseudomonas putida
Authors: Nawaz Mohamed S. , Chapatwala Kirit D. , Wolfram James H.
Published: January 2020

A bacterium capable of utilizing high concentrations of acetonitrile as the sole source of carbon and nitrogen was isolated from soil and identified as
Pseudomonas putida.
This bacterium could also utilize butyronitrile, glutaronitrile, isobutyronitrile, methacrylonitrile, propionitrile, succinonitrile, valeronitrile, and some of their corresponding amides, such as acetamide, butyramide, isobutyramide, methacrylamide, propionamide, and succinamide as growth substrates. Acetonitrile-grown cells oxidized acetonitrile with a

K
m

of 40.61 mM. Mass balance studies with [
14
C]acetonitrile indicated that nearly 66% of carbon of acetonitrile was released as
14
CO
2
and 14% was associated with the biomass. Metabolites of acetonitrile in the culture medium were acetic acid and ammonia. The acetate formed in the early stages of growth completely disappeared in the later stages. Cell extracts of acetonitrile-grown cells contained activities corresponding to nitrile hydratase and amidase, which mediate the breakdown of actonitrile into acetic acid and ammonia. Both enzymes were intracellular and inducible and hydrolyzed a wide range of substrates. The specific activity of amidase was at least 150-fold higher than the activity of the enzyme nitrile hydratase.
Identification of a novel metabolite in phenanthrene metabolism by the fungus Cunninghamella elegans
Authors: Cerniglia C E , Campbell W L , Freeman J P , Evans F E
Published: January 2020

The metabolism of phenanthrene by the fungus Cunninghamella elegans was investigated. Kinetic experiments using [9-14C]phenanthrene showed that after 72 h, 53% of the total radioactivity was associated with a glucoside conjugate of 1-hydroxyphenanthrene (phenanthrene 1-O-beta-glucose). This metabolite was isolated by reversed-phase high-performance liquid chromatography and characterized by the application of UV absorption, 1H nuclear magnetic resonance, and mass spectral techniques. The results show that aromatic ring oxidation followed by glucosylation is a predominant pathway in the metabolism of the polycyclic aromatic hydrocarbon phenanthrene by C. elegans.
Antibiotic resistance of gram-negative enteric bacteria from pigs in three herds with different histories of antibiotic exposure
Authors: Gellin G , Langlois B E , Dawson K A , Aaron D K
Published: January 2020

The antibiotic resistance patterns of gram-negative fecal bacteria from pigs in three herds with different histories of antibiotic exposure were examined. In general, smaller proportions of antibiotic-resistant or multiply resistant fecal isolates (P less than 0.05) were obtained from pigs in a herd not exposed to antimicrobial agents for 154 months than from pigs in a herd continuously exposed to antimicrobial agents at subtherapeutic doses or from pigs in a herd exposed only to therapeutic doses of antimicrobial agents. The proportions of antibiotic-resistant and multiply resistant strains were greater among isolates from pigs in the therapeutic herd than in the non-antibiotic-exposed herd (P less than 0.05). The proportion of antibiotic-resistant isolates in the non-lactose-fermenting population was greater than that in the lactose-fermenting population, regardless of herd. The results suggest that any form of antimicrobial exposure will increase the prevalence of antimicrobial resistance and multiple resistance of fecal bacteria.
Selenate Reduction to Elemental Selenium by Anaerobic Bacteria in Sediments and Culture: Biogeochemical Significance of a Novel, Sulfate-Independent Respiration
Authors: Oremland Ronald S. , Hollibaugh James T. , Maest Ann S. , Presser Theresa S. , Miller Laurence G. , Culbertson Charles W.
Published: January 2020

Interstitial water profiles of SeO
4
2−
, SeO
3
2−
, SO
4
2−
, and Cl
−
in anoxic sediments indicated removal of the seleno-oxyanions by a near-surface process unrelated to sulfate reduction. In sediment slurry experiments, a complete reductive removal of SeO
4
2−
occurred under anaerobic conditions, was more rapid with H
2
or acetate, and was inhibited by O
2
, NO
3
−
, MnO
2
, or autoclaving but not by SO
4
2−
or FeOOH. Oxidation of acetate in sediments could be coupled to selenate but not to molybdate. Reduction of selenate to elemental selenium was determined to be the mechanism for loss from solution. Selenate reduction was inhibited by tungstate and chromate but not by molybdate. A small quantity of the elemental selenium precipitated into sediments from solution could be resolublized by oxidation with either nitrate or FeOOH, but not with MnO
2
. A bacterium isolated from estuarine sediments demonstrated selenate-dependent growth on acetate, forming elemental selenium and carbon dioxide as respiratory end products. These results indicate that dissimilatory selenate reduction to elemental selenium is the major sink for selenium oxyanions in anoxic sediments. In addition, they suggest application as a treatment process for removing selenium oxyanions from wastewaters and also offer an explanation for the presence of selenite in oxic waters.
Epiphytic Occurrence of
Azorhizobium caulinodans
and Other Rhizobia on Host and Nonhost Legumes
Authors: Adebayo A. , Watanabe I. , Ladha J. K.
Published: January 2020

A large population of
Azorhizobium caulinodans
was present on
Sesbania rostrata
; up to 5 × 10
−5
cm
−2
were found on leaves and fewer were found on flowers. Although
A. caulinodans
was also present on the leaves of
Sesbania aculeata
(nonhost), the populations were much smaller than that observed on
S. rostrata
. The population of
S. aculeata
rhizobia on host leaves was less than 30 cm
−2
, and their presence on host flowers was sporadic.
Aeschynomene afraspera
and
Aeschynomene aspera
rhizobia, which are profusely stem nodulating, were found on the leaves of host and nonhost plants and on the flowers of host plants, but,
Aeschynomene pratensis
and
Aeschynomene sensitiva
rhizobia were not found on the leaves and flowers of host plants.
Fungal Catabolism of Crown Gall Opines
Authors: Beauchamp Chantal Jeanne , Chilton William Scott , Dion Patrice , Antoun Hani
Published: January 2020

This study was conducted to determine the capacities of 37 fungi to utilize various crown gall opines as their sole carbon and nitrogen source. One strain of
Fusarium solani,
two of
Cylindrocarpon destructans,
and six of
Cylindrocarpon heteronema
catabolized octopine, mannopine, octopinic acid, succinamopine, or a combination of these opines. One
C. heteronema
and one
Fusarium dimerum
strain grew only on succinamopine. None of the fungal isolates had the ability to grow on nopaline. The catabolism of opines by fungi was confirmed by the disappearance of the opine from the growth medium and by an increase in final mycelial dry weight with rising initial concentration of test substrate. This study thus shows that the catabolism of opines is not restricted to bacteria.
Selective plating medium for quantitative recovery of food-borne Listeria monocytogenes
Authors: Lachica R V
Published: January 2020

A new plating medium (lithium chloride-ceftazidime agar [LCA]) was designed to quantitatively recover food-borne Listeria monocytogenes in the form of large colonies while inhibiting most other food-borne microorganisms. This medium included brain heart infusion agar as the nutritive agar base and a combination of selective agents (LiCl, glycine anhydride, and ceftazidime). Comparison of LCA and lithium chloride-phenylethanol-moxalactam agar (LPM) indicated that both were equally effective for the enumeration of the cold-tolerant pathogen in artificially and naturally contaminated foods. However, LCA was more effective than LPM in the recovery of sublethally heat-injured cells. Moreover, Listeria colonies on LCA exhibited a more distinct bluish hue than those on LPM when viewed by the Henry oblique transillumination technique.
Characterization of pXV10A, a Copper Resistance Plasmid in
Xanthomonas campestris
pv.
vesicatoria
Authors: Bender Carol L. , Malvick Dean K. , Conway Kenneth E. , George Steven , Pratt Phillip
Published: January 2020

The efficacy of copper bactericides for control of
Xanthomonas campestris
pv.
vesicatoria
in eastern Oklahoma tomato fields was evaluated. Copper bactericides did not provide adequate control, and copper-resistant (Cu
r
) strains of the pathogen were isolated. The Cu
r
genes in these strains were located on a large indigenous plasmid designated pXV10A. The host range of pXV10A was investigated; this plasmid was efficiently transferred into 8 of 11
X. campestris
pathovars. However, the transfer of pXV10A to other phytopathogenic genera was not detected. DNA hybridization experiments were performed to characterize the Cu
r
genes on pXV10A. A probe containing subcloned Cu
r
genes from
X. campestris
pv.
vesicatoria
E3C5 hybridized to pXV10A; however, a subclone containing Cu
r
genes from
P. syringae
pv.
tomato
PT23 failed to hybridize to pXV10A. Further DNA hybridization experiments were performed to compare pXV10A with pXvCu plasmids, a heterogenous group of Cu
r
plasmids present in strains of
X. campestris
pv.
vesicatoria
from Florida. These studies indicated that the Cu
r
genes on pXV10A and pXvCu plasmids share nucleotide sequence homology and may have a common origin. Further experiments showed that these plasmids are distinctly different because pXV10A did not contain sequences homologous to IS
476
, an insertion sequence present on pXvCu plasmids.
pAMβ1-Associated Mobilization of Proteinase Plasmids from
Lactococcus lactis
subsp.
lactis
UC317 and
L. lactis
subsp.
cremoris
UC205
Authors: Hayes Finbarr , Caplice Elizabeth , McSweeney Anne , Fitzgerald Gerald F. , Daly Charles
Published: January 2020

A combination of plasmid curing and DNA-DNA hybridization data facilitated the identification of proteinase plasmids of 75 (pCI301) and 35 kilobases (pCI203) in the multi-plasmid-containing strains
Lactococcus lactis
subsp.
lactis
UC317 and
L. lactis
subsp.
cremoris
UC205, respectively. Both plasmids were transferred by conjugation to a plasmid-free background only after introduction of the conjugative streptococcal plasmid, pAMβ1. All Prt
+
transconjugants from matings involving either donor contained enlarged recombinant Prt plasmids. UC317-derived transconjugants were separable into different classes based on the presence of differently sized cointegrate plasmids and on segregation of the pCI301-derived Lac and Prt markers. All UC205-derived transconjugants harbored a single enlarged plasmid that was a cointegrate between pCI203 and pAMβ1. The identification of
prt
genes on pCI301 and pCI203 derivatives was achieved by a combination of restriction enzyme and hybridization analyses.
Oxidation of Lignin-Related Aromatic Alcohols by Cell Suspensions of
Methylosinus trichosporium
Authors: Mountfort Douglas O. , White David , Asher Rodney A.
Published: January 2020

Cell suspensions of
Methylosinus trichosporium
oxidized the aromatic alcohols benzyl alcohol, vanillyl alcohol, and veratryl alcohol to the corresponding aldehydes, and with the exception of vanillyl alcohol, the aldehydes were further oxidized to the corresponding aromatic acids. No other transformation was observed, and the methoxyl moieties attached to the aromatic nucleus remained intact. More than 70% of the alcohol oxidized could be accounted for by aldehyde and/or acid. Investigation of the inhibitor kinetics of EDTA or
p
-nitrophenylhydrazine (specific for NAD
+
-independent methanol dehydrogenase in methylotrophs) on aromatic alcohol oxidation revealed noncompetitive inhibition in which the
V
max
was decreased but the
K

m

remained unchanged. The pattern of inhibition of aromatic alcohol oxidation matched that of methanol oxidation, and the
K

m

values for all of the substrates were similar (12 to 16 mM). The results indicate that the initial step in the oxidation of aromatic alcohols was similar to that for methanol, and because oxidation was incomplete (i.e., only the corresponding aldehyde or acid was produced), there may be some biotechnological advantages in using whole cells of methylotrophs to facilitate aromatic biotransformations.
Model for inactivation and disposal of infectious human immunodeficiency virus and radioactive waste in a BL3 facility
Authors: Stinson M C , Galanek M S , Ducatman A M , Masse F X , Kuritzkes D R
Published: January 2020

A method is described for autoclaving low levels of solid infectious, radioactive waste. The method permits steam penetration to inactivate biologic waste, while any volatile radioactive compounds generated during the autoclave process are absorbed. Inactivation of radiolabeled infectious waste has been problematic because the usual sterilization techniques result in unacceptable radiation handling practices. If autoclaved under the usual conditions, there exists a high probability of volatilization or release of radioisotopes from the waste. This results in the radioactive contamination of the autoclave and the laboratory area where steam is released from the autoclave. Our results provide a practical method to inactivate and dispose of infectious radioactive waste. For our research, Bacillus pumilus spore strips and vaccinia virus were used as more heat-resistant surrogates of the human immunodeficiency virus (HIV). These surrogates were used because HIV is difficult to grow under most conditions and is less heat tolerant than the surrogates. In addition, B. pumilus has defined cell death values, whereas such values have not been established for HIV. Both B. pumilus and vaccinia virus are less hazardous to work with. The autoclave method is time efficient and can be performed by laboratory personnel with minimal handling of the waste. Furthermore, waste site handlers are able to visually inspect the solid waste containers and ascertain that inactivation procedures have been implemented.
Transient-State Analysis of Metabolic Fluxes in Crabtree-Positive and Crabtree-Negative Yeasts
Authors: Van Urk Hendrik , Voll W. S. Leopold , Scheffers W. Alexander , Van Dijken Johannes P.
Published: January 2020

In bakers' yeast, an immediate alcoholic fermentation begins when a glucose pulse is added to glucose-limited, aerobically grown cells. The mechanism of this short-term Crabtree effect was investigated via a comparative enzymic analysis of eight yeast species. It was established that the fermentation rate of the organisms upon transition from glucose limitation to glucose excess is positively correlated with the level of pyruvate decarboxylase (EC 4.1.1.1). In the Crabtree-negative yeasts, the pyruvate decarboxylase activity was low and did not increase when excess glucose was added. In contrast, in the Crabtree-positive yeasts, the activity of this enzyme was on the average sixfold higher and increased after exposure to glucose excess. In Crabtree-negative species, relatively high activities of acetaldehyde dehydrogenases (EC 1.2.1.4 and EC 1.2.1.5) and acetyl coenzyme A synthetase (EC 6.2.1.1), in addition to low pyruvate decarboxylase activities, were present. Thus, in these yeasts, acetaldehyde can be effectively oxidized via a bypass that circumvents the reduction of acetaldehyde to ethanol. Growth rates of most Crabtree-positive yeasts did not increase upon transition from glucose limitation to glucose excess. In contrast, the Crabtree-negative yeasts exhibited enhanced rates of biomass production which in most cases could be ascribed to the intracellular accumulation of reserve carbohydrates. Generally, the glucose consumption rate after a glucose pulse was higher in the Crabtree-positive yeasts than in the Crabtree-negative yeasts. However, the respiratory capacities of steady-state cultures of Crabtree-positive yeasts were not significantly different from those of Crabtree-negative yeasts. Thus, a limited respiratory capacity is not the primary cause of the Crabtree effect in yeasts. Instead, the difference between Crabtree-positive and Crabtree-negative yeasts is attributed to differences in the kinetics of glucose uptake, synthesis of reserve carbohydrates, and pyruvate metabolism.
Influence of water activity and temperature on survival of and colony formation by heat-stressed Chrysosporium farinicola aleuriospores
Authors: Beuchat L R , Pitt J I
Published: January 2020

The ability of sublethally heat-stressed aleuriospores of Chrysosporium farinicola to form colonies on yeast extract-glucose agar (YGA) supplemented with sufficient glucose, sorbitol, glycerol, and NaCl to achieve reduced water activity (aw) in the range of 0.88 to 0.95 was determined. The effects of the aw of diluent and incubation temperature during recovery and colony formation were also investigated. Aleuriospores harvested from 14-day-old cultures grown at 25 degrees C were less resistant to heat inactivation compared with aleuriospores from 20-day-cultures. Increased populations of heat-stressed aleuriospores were recovered as the aw of YGA was decreased from 0.95 (glucose and glycerol) and 0.94 (sorbitol) to 0.89 and 0.88, respectively. In NaCl-supplemented YGA, populations recovered at an aw of 0.94 were greatly reduced compared with populations detected at an aw of 0.92; no colonies were formed on NaCl-supplemented YGA at an aw of 0.88. Tolerance to aw values above 0.88 to 0.89 as influenced by solute type was in the order of glucose greater than sorbitol greater than glycerol greater than NaCl. Incubation at 20 degrees generally resulted in an increase in recoverable aleuriospores compared with incubation at 25 degrees C or at 30 degrees C for 14 days followed by 20 degrees C for 10 days. The lethal effect of NaCl on heat-stressed aleuriospores was enhanced at 30 degrees C. The retention of viability of aleuriospores held in sucrose-peptone water diluent (aw, 0.936) for 20 min was essentially the same as that observed when aleuriospores were held in peptone water (aw, 0.997).(ABSTRACT TRUNCATED AT 250 WORDS)
Distribution of Legionella longbeachae serogroup 1 and other legionellae in potting soils in Australia
Authors: Steele T W , Moore C V , Sangster N
Published: January 2020

Legionella longbeachae serogroup 1 and other Legionella spp. were isolated from 73% of 45 potting soils made in Australia by 13 manufacturers but were not detected in 19 potting soils made in Greece, Switzerland, and the United Kingdom examined between March 1989 and May 1990. Several Legionella species were isolated from a small number of samples of uncomposted pine sawdusts, but it is not known whether sawdust was the source of some of the legionellae found in potting soils. Legionella spp. persisted for periods ranging from 3 to 10 months in a potting soil held at temperatures between -20 and 35 degrees C. Isolates of L. longbeachae serogroup 1 from soil did not grow at 43 degrees C, a temperature which was also lethal for this species in soil. Most Legionella spp. isolated from potting and natural soils belonged to one distinct group according to analysis of ubiquinones and were serologically related to several known species in this group. A small number of potting soils contained L. pneumophila and L. micdadei.
Anaerobic Aryl Reductive Dehalogenation of Halobenzoates by Cell Extracts of “
Desulfomonile tiedjei
”
Authors: DeWeerd Kim A. , Suflita Joseph M.
Published: January 2020

We studied the transformation of halogenated benzoates by cell extracts of a dehalogenating anaerobe, “
Desulfomonile tiedjei
.” We found that cell extracts possessed aryl reductive dehalogenation activity. The activity was heat labile and dependent on the addition of reduced methyl viologen, but not on that of reduced NAD, NADP, flavin mononucleotide, flavin adenine dinucleotide, desulfoviridin, cytochrome
c
3
, or benzyl viologen. Dehalogenation activity in extracts was stimulated by formate, CO, or H
2
, but not by pyruvate plus coenzyme A or by dithionite. The pH and temperature optima for aryl dehalogenation were 8.2 and 35°C, respectively. The rate of dehalogenation was proportional to the amount of protein in the assay mixture. The substrate specificity of aryl dehalogenation activity for various aromatic compounds in “
D. tiedjei
” cell extracts was identical to that of whole cells, except differences were observed in the relative rates of halobenzoate transformation. Dehalogenation was 10-fold greater in “
D. tiedjei
” extracts prepared from cells cultured in the presence of 3-chlorobenzoate, suggesting that the activity was inducible. Aryl reductive dehalogenation in extracts was inhibited by sulfite, sulfide, and thiosulfate, but not sulfate. Experiments with combinations of substrates suggested that cell extracts dehalogenated 3-iodobenzoate more readily than either 3,5-dichlorobenzoate or 3-chlorobenzoate. Dehalogenation activity was found to be membrane associated. This is the first report characterizing aryl dehalogenation activity in cell extracts of an obligate anaerobe.
Biomass and Biological Activity during the Production of Compost Used as a Substrate in Mushroom Cultivation
Authors: Derikx Piet J. L. , Op Den Camp Huub J. M. , van der Drift Chris , Van Griensven Leo J. L. D. , Vogels Godfried D.
Published: January 2020

The production of a suitable substrate for the cultivation of the common white button mushroom,
Agaricus bisporus
, is referred to as composting. High microbiological activity causes temperatures of the composting material to rise as high as 80°C. At stacking, an optimal oxygen consumption rate of 140 μmol of O
2
h
−1
g (dry weight)
−1
was found in the compost at 50°C, whereas the oxygen consumption rate of the end product was lower at all temperatures tested. No significant differences were observed between biomass content and mineralization rate of
14
C-labeled glutamate of the two composts. Biomass content was shown to be a major function of both temperature and the sampling site position in the stack. On the basis of the results reported here, a minimal composting time of 3.3 days for the phase I process was calculated. Further suggestions are made to reduce the time necessary for the production of a substrate for
A. bisporus
considerably.
Subcellulosome preparation with high cellulase activity from Clostridium thermocellum
Authors: Kobayashi T , Romaniec M P , Fauth U , Demain A L
Published: January 2020

We have prepared a much simpler cellulase preparation than that of cellulosomes from the extracellular broth of Clostridium thermocellum. This "subcellulosome" preparation from C. thermocellum was obtained by column chromatography on CM-Bio-Gel A and then on a lectin-affinity material (Jacalin). The subcellulosome preparation is a macromolecular complex, composed of six main protein subunits (molecular weight, 210,000 to 58,000) revealed on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The specific activities of carboxymethylcellulase (CMCase) and Avicelase are 15- and 8-fold-higher, respectively, than those of crude extracellular cellulase. We could not further fractionate this preparation without denaturing it. The optimum pH and temperature of the subcellulosome preparation are 5.5 to 7.0 and 70 degrees C for CMCase and 5.5 to 7.0 and 65 degrees C for Avicelase. The subcellulosome preparation acted on various types of carboxymethyl cellulose, cellulose, and p-nitrophenyl-beta-D-cellobioside but not on p-nitrophenyl-beta-D-glucoside. Sulfhydryl reagents and N-bromosuccinimide inhibited both CMCase and Avicelase activities, whereas EDTA and o-phenanthroline inhibited Avicelase activity only.
Genetic Transformation of the Biocontrol Fungus
Gliocladium virens
to Benomyl Resistance
Authors: Ossanna Nina , Mischke Sue
Published: January 2020

Methodology was developed to isolate and regenerate protoplasts from the biocontrol fungus
Gliocladium virens
and to transform them to benomyl resistance with a
Neurospora crassa
β-tubulin gene. Southern blots demonstrated that multiple copies of the vector integrated into the chromosomal DNA of stable biotypes but not of abortive transformants. Analysis of nuclear condition in vegetative and asexual structures demonstrated that no structure of
G. virens
is dependably uninucleate and thus preferentially suitable for transformation.
Co-Occlusion and Persistence of a Baculovirus Mutant Lacking the Polyhedrin Gene
Authors: Hamblin Martha , Van Beek Nikolai A. M. , Hughes Patrick R. , Wood H. Alan
Published: January 2020

A co-occlusion process was evaluated as a commercially and ecologically acceptable strategy for the development of genetically improved baculovirus insecticides. Coinfection of
Spodoptera frugiperda
(IPLB-SF-21) tissue culture cells with
Autographa californica
nuclear polyhedrosis virus (AcMNPV) and an AcMNPV mutant (Ac-E10) lacking the polyhedrin gene resulted in occlusion of both virus types within polyhedra. The amount of occluded Ac-E10 virions in progeny polyhedra populations during serial passage in
Trichoplusia ni
larvae was evaluated. Maintenance of the mutant in progeny polyhedra required polyhedra inocula containing equal numbers of the two virus types at a high dose. A significant reduction in occluded mutant nucleocapsids occurs with inoculum levels below a 100% lethal dose. At inoculum levels below a 30% lethal dose, the majority of fourth-instar larvae were infected with only one type of virus. The commercial application and ecological advantages of the co-occlusion process are discussed.
Kinetics of the Methanogenic Fermentation of Acetate
Authors: Fukuzaki Satoshi , Nishio Naomichi , Nagai Shiro
Published: January 2020

Inhibition of the fermentation of acetate to methane and carbon dioxide by acetate was analyzed with an acetate-acclimatized sludge and with
Methanosarcina barkeri
Fusaro under mesophilic conditions. A second-order substrate inhibition model,
q

ch
4

=

q
m
S

/[

K
s

+
S
+ (
S
2
/

K
i

)], where
S
was the concentration of undissociated acetic acid, not ionized acetic acid, could be applicable in both cases. The analysis resulted in substrate saturation constants,

K
s

, of 4.0 μM for the acclimatized sludge and 104 μM for
M. barkeri.
The threshold concentrations of undissociated acetic acid when no further acetate utilization was observed were 0.078 μM (pH 7.50) for the acclimatized sludge and 4.43 μM (pH 7.45) for
M. barkeri.
These kinetic results suggested that the concentration of undissociated acetic acid became a key factor governing the actual threshold acetate concentration for acetate utilization and that the acclimatized sludge in which
Methanothrix
spp. appeared dominant could utilize acetate better and survive at a lower concentration of undissociated acetic acid than could
M. barkeri.
Increased Accumulation of Trehalose in Rhizobia Cultured under 1% Oxygen
Authors: Hoelzle Inger , Streeter John G.
Published: January 2020

The growth of rhizobia under 1% O
2
induced the accumulation of α,α-trehalose, and the effect of low O
2
was independent of medium composition and
Rhizobium
species. Trehalose concentration in cells declined rapidly when microaerobic cultures were supplied with 21% O
2
. Trehalose formation in nodules may be induced by the microaerobic environment.
Thermotolerance of Listeria monocytogenes and Salmonella typhimurium after sublethal heat shock
Authors: Bunning V K , Crawford R G , Tierney J T , Peeler J T
Published: January 2020

The effect of prior heat shock on thermotolerance of Listeria monocytogenes and Salmonella typhimurium in broth culture was determined. Bacteria were grown at the permissive temperature of 35 degrees C, sublethally heated at 35 (control), 42, 48, and 52 degrees C (nonpermissive control) for various times, and inactivated at either 57.8 or 52 degrees C. The induction of increased thermotolerance by heat shock, although consistent within each experiment, was generally not significant for L. monocytogenes; the increase was significant for S. typhimurium. Temperature shift experiments with L. monocytogenes suggested that induced thermotolerance was not long lived unless the shock temperature was maintained.
3-Phenylpropanoic Acid Improves the Affinity of
Ruminococcus albus
for Cellulose in Continuous Culture
Authors: Morrison Mark , Mackie Roderick I. , Kistner Albrecht
Published: January 2020

A continuous-culture device, adapted for use with solid substrates, was used to evaluate the effects of 3-phenylpropanoic acid (PPA) upon the ability of the South African strain
Ruminococcus albus
Ce63 to ferment cellulose. Steady states of fermentation were established with a dilution rate of 0.17 h
−1
, and the extent and volumetric rates of cellulose fermentation were determined over four consecutive days. When the growth medium contained no additions (control), 25 μM phenylacetate alone, 25 μM PPA alone, or 25 μM each of phenylacetate and PPA, the extent of cellulose hydrolysis was determined to be 41.1, 35.7, 90.2, and 86.9%, respectively, and the volumetric rate of cellulose hydrolysis was 103.0, 97.9, 215.5, and 230.4 mg liter
−1
h
−1
, respectively. To evaluate the effect of PPA availability on affinity for cellulose, the values for dilution rate and extent of cellulose hydrolysis were used in combination with values for maximum specific growth rate determined from previous studies of growth rates and kinetics of cellulose hydrolysis. The findings support the contention that PPA maintains a competitive advantage for
R. albus
when grown in a dynamic, fiber-rich environment.
Transformation of carbon tetrachloride by Pseudomonas sp. strain KC under denitrification conditions
Authors: Criddle C S , DeWitt J T , Grbić-Galić D , McCarty P L
Published: January 2020

A denitrifying Pseudomonas sp. (strain KC) capable of transforming carbon tetrachloride (CT) was isolated from groundwater aquifer solids. Major products of the transformation of 14C-labeled CT by Pseudomonas strain KC under denitrification conditions were 14CO2 and an unidentified water-soluble fraction. Little or no chloroform was produced. Addition of dissolved trace metals, notably, ferrous iron and cobalt, to the growth medium appeared to enhance growth of Pseudomonas strain KC while inhibiting transformation of CT. It is hypothesized that transformation of CT by this organism is associated with the mechanism of trace-metal scavenging.
Selective Medium for Isolation of
Mycoleptodiscus terrestris
from Soil Sediments of Aquatic Environments
Authors: Sneh Baruch , Stack James
Published: January 2020

A selective medium was developed for the dilution plate isolation of
Mycoleptodiscus terrestris
from natural soils and sediments from aquatic environments. The ingredients per liter of the selective medium are as follows: KH
2
PO
4
, 0.5 g; MgSO
4
7H
2
O, 0.5 g; dextrose, 10.0 g; peptone, 5.0 g; chloramphenicol, 0.25 g; rose bengal, 50 mg; oxgall, 5.0 g; Terraclor (pentachloronitrobenzene, 75% active ingredients), 0.5 g; agar, 15.0 g. After autoclaving, the following ingredients were aseptically added: sorbic acid (0.7% autoclave-sterilized aqueous solution), 5.0 ml; Subdue (25.1% emulsion of metalaxyl), 0.5 ml; Truban (40.7% suspension of etridiazol), 0.05 ml. The colony-restrictive properties of this medium enabled its use in the drop plate method, originally developed for viable counts of bacteria. Alfalfa sprouts as baits were not suitable for quantitative recovery of the fungus, although 5% of alfalfa sprouts were infected with
M. terrestris
when incubated on soil containing 1.5 × 10
2
CFU/g.
Sensitive enzyme-amplified electrical immunoassay for protein A-bearing Staphylococcus aureus in foods
Authors: Brooks J L , Mirhabibollahi B , Kroll R G
Published: January 2020

An amperometric electrochemical immunoassay specific for protein A-bearing Staphylococcus aureus was developed. The method was based on a sandwich immunosorbent assay and incorporated an enzyme amplification step, using a NAD-specific redox cycle generating NADH (C. H. Stanley, A. Johannsson, and C. H. Self, J. Immunol. Methods 83:89-95, 1985). Reduction of the mediator, ferricyanide, was dependent on the initial concentration of antigen. The final potential was measured by using a Pt disk electrode polarized at +0.8 V to the Ag/AgCl reference electrode. The assay was rapid (4 h) and generated protein A- and cell (S. aureus)-dependent signals. The system was highly sensitive and could detect 10 pg of protein A ml-1 and less than 100 CFU of S. aureus ml-1. Similar sensitivities were observed with S. aureus cultures inoculated into beef and milk, but the sensitivity was reduced slightly (ca. 10(3) g-1) with samples of Cheddar cheese.
Low-affinity, high-capacity system of glucose transport in the ruminal bacterium Streptococcus bovis: evidence for a mechanism of facilitated diffusion
Authors: Russell J B
Published: January 2020

The glucose phosphotransferase system (PTS) of Streptococcus bovis could not account for the glucose consumption of exponential cultures, and the kinetics of glucose transport were biphasic. A PTS-deficient mutant lost the high-affinity, low-capacity system but retained its ability to take up glucose at high substrate concentrations. The low-affinity, high-capacity system did not require a proton motive force or ATP and could not be driven by an artificial membrane potential in the presence or absence of sodium. Since low-affinity transport was directly proportional to the external substrate concentration and exhibited counterflow kinetics, it appeared that a facilitated-diffusion mechanism was responsible for glucose transport at high substrate concentrations.
Formation of polyesters consisting of medium-chain-length 3-hydroxyalkanoic acids from gluconate by Pseudomonas aeruginosa and other fluorescent pseudomonads
Authors: Timm A , Steinbüchel A
Published: January 2020

Pseudomonas aeruginosa PAO and 15 other strains of this species synthesized a polyester with 3-hydroxydecanoate as the main constituent (55 to 76 mol%) if the cells were cultivated in the presence of gluconate and if the nitrogen source was exhausted; 3-hydroxyhexanoate, 3-hydroxyoctanoate, and 3-hydroxydodecanoate were minor constituents of the polymer. The polymer was deposited in granules within the cell and amounted to 70% of the cell dry matter in some strains. Among 55 different strains of 41 Pseudomonas species tested, P. aureofaciens (21.6% of cellular dry matter), P. citronellolis (78.0%), P. chlororaphis (8.5%), P. marginalis (11.4%), P. mendocina (50.7%), P. putida (33.5%), and Pseudomonas sp. strain DSM 1650 (54.6%) accumulated this type of polymer at significant levels (greater than 5%) during cultivation on gluconate. In two strains of P. facilis and P. fluorescens, as well as in one strain of P. syringae, this polymer was detected as a minor constituent (much less than 5%). All other strains accumulated either poly(3-hydroxybutyrate) or a polymer consisting mainly of 3-hydroxyoctanoate with octanoate but no polyester with gluconate as the carbon source. Only a few species (e.g., P. stutzeri) were unable to accumulate poly(hydroxyalkanoic acids) (PHA) at all. These results indicated that the formation of PHA depends on a pathway which is distinct from all other known PHA-biosynthetic pathways. The polyesters accumulated by gluconate- or octanoate-grown cells of recombinant strains of P. aeruginosa and P. putida, which harbored the Alcaligenes eutrophus poly(3-hydroxybutyrate)biosynthetic genes, contained 3-hydroxybutyrate as an additional constituent.
Effect of Oxygenation on Xylose Fermentation by
Pichia stipitis
Authors: Skoog Kerstin , Hahn-Hägerdal Bärbel
Published: January 2020

The effect of oxygen limitation on xylose fermentation by
Pichia stipitis
(CBS 6054) was investigated in continuous culture. The maximum specific ethanol productivity (0.20 g of ethanol g dry weight
−1
h
−1
) and ethanol yield (0.48 g/g) was reached at an oxygen transfer rate below 1 mmol/liter per h. In the studied range of oxygenation, the xylose reductase (EC 1.1.1.21) and xylitol dehydrogenase (EC 1.1.1.9) activities were constant as well as the ratio between the NADPH and NADH activities of xylose reductase. No xylitol production was found. The pyruvate decarboxylase (EC 4.1.1.1) activity increased and the malate dehydrogenase (EC 1.1.1.37) activity decreased with decreasing oxygenation. With decreasing oxygenation, the intracellular intermediary metabolites sedoheptulose 7-phosphate, glucose 6-phosphate, fructose 1,6-diphosphate, and malate accumulated slightly while pyruvate decreased. The ratio of the xylose uptake rate under aerobic conditions, in contrast to that under anaerobic assay conditions, increased with increasing oxygenation in the culture. The results are discussed in relation to the energy level in the cell, the redox balance, and the mitochondrial function.
Rapid Methane Oxidation in a Landfill Cover Soil
Authors: Whalen S. C. , Reeburgh W. S. , Sandbeck K. A.
Published: January 2020

Methane oxidation rates observed in a topsoil covering a retired landfill are the highest reported (45 g m
−2
day
−1
) for any environment. This microbial community had the capacity to rapidly oxidize CH
4
at concentrations ranging from <1 ppm (microliters per liter) (first-order rate constant [
k
] = −0.54 h
−1
) to >10
4
ppm (
k
= −2.37 h
−1
). The physiological characteristics of a methanotroph isolated from the soil (characteristics determined in aqueous medium) and the natural population, however, were similar to those of other natural populations and cultures: the
Q
10
and optimum temperature were 1.9 and 31°C, respectively, the apparent half-saturation constant was 2.5 to 9.3 μM, and 19 to 69% of oxidized CH
4
was assimilated into biomass. The CH
4
oxidation rate of this soil under waterlogged (41% [wt/vol] H
2
O) conditions, 6.1 mg liter
−1
day
−1
, was near rates reported for lake sediment and much lower than the rate of 116 mg liter
−1
day
−1
in the same soil under moist (11% H
2
O) conditions. Since there are no large physiological differences between this microbial community and other CH
4
oxidizers, we attribute the high CH
4
oxidation rate in moist soil to enhanced CH
4
transport to the microorganisms; gas-phase molecular diffusion is 10
4
-fold faster than aqueous diffusion. These high CH
4
oxidation rates in moist soil have implications that are important in global climate change. Soil CH
4
oxidation could become a negative feedback to atmospheric CH
4
increases (and warming) in areas that are presently waterlogged but are projected to undergo a reduction in summer soil moisture.
Novel cloning vectors for Bacillus thuringiensis
Authors: Baum J A , Coyle D M , Gilbert M P , Jany C S , Gawron-Burke C
Published: January 2020

Seven replication origins from resident plasmids of Bacillus thuringienis subsp. kurstaki HD263 and HD73 were cloned in Escherichia coli. Three of these replication origins, originating from plasmids of 43, 44, and 60 MDa, were used to construct a set of compatible shuttle vectors that exhibit structural and segregational stability in the Cry- strain B. thuringiensis HD73-26. These shuttle vectors, pEG597, pEG853, and pEG854, were designed with rare restriction sites that permit various adaptations, including the construction of small recombinant plasmids lacking antibiotic resistance genes. The cryIA(c) and cryIIA insecticidal crystal protein genes were inserted into these vectors to demonstrate crystal protein production in B. thuringiensis. Introduction of a cloned cryIA(c) gene from strain HD263 into a B. thuringiensis subsp. aizawai strain exhibiting good insecticidal activity against Spodoptera exigua resulted in a recombinant strain with an improved spectrum of insecticidal activity. Shuttle vectors of this sort should be valuable in future genetic studies of B. thuringiensis as well as in the development of B. thuringiensis strains for use as microbial pesticides.