bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of Airborne Actinomycete Spores with Fluorogenic Substrates
Authors: Gazenko S. V. , Reponen T. A. , Grinshpun S. A. , Willeke K. 
Published: December 2019

ABSTRACT

The reactions between seven fluorogenic substrates and different groups of enzymes, esterases, lipases, phosphatases, and dehydrogenases, were studied in a search for a new method for the detection of actinomycete spores. Fluorescence measurement was chosen as a fast and sensitive method for microbial analysis. The focus of the research was on the spores of important air contaminants:
Streptomyces albus
and
Thermoactinomyces vulgaris
. For the measurement of the enzymatic activity, the chosen fluorogenic substrate was added to a mixture of spores and nutrient media, and the resulting fluorescence was measured with a spectrofluorometer. Fluorogenic substrates were found to show enzymatic activities even for dormant spores. Comparison of the enzymatic activities of dormant spores with those of vegetative cells showed similarity of the enzymatic profiles but higher activity for vegetative cells. The increase of enzymatic activity from dormant spores to vegetative cells was not linear but fluctuating. The largest fluctuations were found after 4 to 5 h of incubation. The enzymatic activities of
S. albus
were 10 to 50 times lower than those of
T. vulgaris
, except for the dehydrogenase activity, which was seven times higher. These results indicate that analysis with fluorogenic substrates has the potential for becoming a fast and sensitive method for the enumeration and identification of airborne actinomycete spores.
Molecular Characterization and Expression of a Phytase Gene from the Thermophilic Fungus
Thermomyces lanuginosus
Authors: Berka Randy M. , Rey Michael W. , Brown Kimberly M. , Byun Tony , Klotz Alan V. 
Published: December 2019

ABSTRACT

The
phyA
gene encoding an extracellular phytase from the thermophilic fungus
Thermomyces lanuginosus
was cloned and heterologously expressed, and the recombinant gene product was biochemically characterized. The
phyA
gene encodes a primary translation product (PhyA) of 475 amino acids (aa) which includes a putative signal peptide (23 aa) and propeptide (10 aa). The deduced amino acid sequence of PhyA has limited sequence identity (ca. 47%) with
Aspergillus niger
phytase. The
phyA
gene was inserted into an expression vector under transcriptional control of the
Fusarium oxysporum
trypsin gene promoter and used to transform a
Fusarium venenatum
recipient strain. The secreted recombinant phytase protein was enzymatically active between pHs 3 and 7.5, with a specific activity of 110 μmol of inorganic phosphate released per min per mg of protein at pH 6 and 37°C. The
Thermomyces
phytase retained activity at assay temperatures up to 75°C and demonstrated superior catalytic efficiency to any known fungal phytase at 65°C (the temperature optimum). Comparison of this new
Thermomyces
catalyst with the well-known
Aspergillus niger
phytase reveals other favorable properties for the enzyme derived from the thermophilic gene donor, including catalytic activity over an expanded pH range.
Characterization of a Strain of Infectious Hepatitis E Virus Isolated from Sewage in an Area where Hepatitis E Is Not Endemic
Authors: Pina Sonia , Jofre Joan , Emerson Suzanne U. , Purcell Robert H. , Girones Rosina 
Published: December 2019

ABSTRACT
Raw sewage samples from an area where hepatitis E is not endemic (Barcelona, Spain) were analyzed by reverse transcriptase-PCR followed by nested PCR. One of the 37 tested samples showed a positive result for hepatitis E virus (HEV). The detected strain was amplified by inoculation into rhesus monkeys, and the course of the infection was studied by analyzing serological and biochemical parameters and by monitoring the presence of HEV in serum and feces. Fecal suspensions from the rhesus monkeys were used as the source of viral particles for sequence analysis. Eighty percent of the genome of the isolated strain, named BCN, was sequenced and found to be phylogenetically related to Asian (Indian) strains, with a 98% nucleotide identity with an isolate from Madras, India. Since this was a single isolation we cannot conclude that HEV is regularly present in the sewage. However, the finding of viable HEV in sewage has implications for contamination of the environment and shellfish by HEV and must be considered in the diagnosis of viral hepatitis in regions of nonendemic hepatitis.
Effect of Prior Exposure to Noninfected Ticks on Susceptibility of Mice to Lyme Disease Spirochetes
Authors: Richter Dania , Spielman Andrew , Matuschka Franz-Rainer 
Published: December 2019

ABSTRACT

To determine whether prior exposure to Nearctic
Ixodes
vector ticks protects native reservoir mice from tick-borne infection by Lyme disease spirochetes, we compared their infectivities for white-footed mice and laboratory mice that had been repeatedly infested by noninfected deer ticks. Nymphal ticks readily engorged on tick-exposed laboratory mice, but their feeding success on white-footed mice progressively declined. Tick-borne spirochetes readily infected previously tick-infested mice. Thus, prior infestation by Nearctic ticks does not protect sympatric reservoir mice or Palearctic laboratory mice from infection by sympatric tick-borne spirochetes.
Degradation of Polychlorinated Biphenyl Metabolites by Naphthalene-Catabolizing Enzymes
Authors: Barriault Diane , Durand Jacinthe , Maaroufi Halim , Eltis Lindsay D. , Sylvestre Michel 
Published: December 2019

ABSTRACT

The ability of the dehydrogenase and ring cleavage dioxygenase of the naphthalene degradation pathway to transform 3,4-dihydroxylated biphenyl metabolites was investigated. 1,2-Dihydro-1,2-dihydroxynaphthalene dehydrogenase was expressed as a histidine-tagged protein. The purified enzyme transformed 2,3-dihydro-2,3-dihydroxybiphenyl, 3,4-dihydro-3,4-dihydroxybiphenyl, and 3,4-dihydro-3,4-dihydroxy-2,2′,5,5′-tetrachlorobiphenyl to 2,3-dihydroxybiphenyl, 3,4-dihydroxybiphenyl (3,4-DHB), and 3,4-dihydroxy-2,2′,5,5′-tetrachlorobiphenyl (3,4-DH-2,2′,5,5′-TCB), respectively. Our data also suggested that purified 1,2-dihydroxynaphthalene dioxygenase catalyzed the
meta
cleavage of 3,4-DHB in both the 2,3 and 4,5 positions. This enzyme cleaved 3,4-DH-2,2′,5,5′-TCB and 3,4-DHB at similar rates. These results demonstrate the utility of the naphthalene catabolic enzymes in expanding the ability of the
bph
pathway to degrade polychlorinated biphenyls.
Geographic Risk for Lyme Disease and Human Granulocytic Ehrlichiosis in Southern New York State
Authors: Daniels Thomas J. , Boccia Theresa M. , Varde Shobha , Marcus Jonathan , Le Jianhua , Bucher Doris J. , Falco Richard C. , Schwartz Ira 
Published: December 2019

ABSTRACTIxodes scapularis, the tick vector of Lyme disease and human granulocytic ehrlichiosis (HGE), is prevalent in much of southern New York state. The distribution of this species has increased, as have reported cases of both Lyme disease and HGE. The unreliability of case reports, however, demonstrates the need for tick and pathogen surveillance in order to accurately define areas of high risk. In this study, a total of 89,550 m2at 34 study sites was drag sampled in 1995 and a total of 51,540 m2at 40 sites was sampled in 1996 to determine tick and pathogen distribution in southern New York state.I. scapulariswas collected from 90% of the sites sampled, and regionally, a 2.5-fold increase in nymphal abundance occurred from 1995 to 1996.I. scapularisindividuals from all sites were infected withBorrelia burgdorferiin 1995, while an examination of ticks for bothB. burgdorferiand the agent of HGE in 1996 confirmed that these organisms were present in all counties; the average coinfection rate was 1.9%. No correlation was found between estimated risk and reported cases of Lyme disease. The geographic disparity of risk observed among sites in this study underscores the need for vector and pathogen surveillance on a regional level. An entomologic risk index can help identify sites for targeted tick control efforts.
Isolation of Marine Polycyclic Aromatic Hydrocarbon (PAH)-Degrading
Cycloclasticus
Strains from the Gulf of Mexico and Comparison of Their PAH Degradation Ability with That of Puget Sound
Cycloclasticus
Strains
Authors: Geiselbrecht Allison D. , Hedlund Brian P. , Tichi Mary A. , Staley J. T. 
Published: December 2019

ABSTRACT

Phenanthrene- and naphthalene-degrading bacteria were isolated from four offshore and nearshore locations in the Gulf of Mexico by using a modified most-probable-number technique. The concentrations of these bacteria ranged from 10
2
to 10
6
cells per ml of wet surficial sediment in mildly contaminated and noncontaminated sediments. A total of 23 strains of polycyclic aromatic hydrocarbon (PAH)-degrading bacteria were obtained. Based on partial 16S ribosomal DNA sequences and phenotypic characteristics, these 23 strains are members of the genus
Cycloclasticus
. Three representatives were chosen for a complete phylogenetic analysis, which confirmed the close relationship of these isolates to type strain
Cycloclasticus pugetii
PS-1, which was isolated from Puget Sound. PAH substrate utilization tests which included high-molecular-weight PAHs revealed that these isolates had similar, broad substrate ranges which included naphthalene, substituted naphthalenes, phenanthrene, biphenyl, anthracene, acenaphthene, and fluorene. Degradation of pyrene and fluoranthene occurred only when the strains were incubated with phenanthrene. Two distinct partial PAH dioxygenase iron sulfur protein (ISP) gene sequences were PCR amplified from Puget Sound and Gulf of Mexico
Cycloclasticus
strains. Phylogenetic analyses of these sequences revealed that one ISP type is related to the
bph
type of ISP sequences, while the other ISP type is related to the
nah
type of ISP sequences. The predicted ISP amino acid sequences for the Gulf of Mexico and Puget Sound strains are identical, which supports the hypothesis that these geographically separated isolates are closely related phylogentically.
Cycloclasticus
species appear to be numerically important and widespread PAH-degrading bacteria in both Puget Sound and the Gulf of Mexico.
Purification and Characterization of Gallic Acid Decarboxylase from
Pantoea agglomerans
T71
Authors: Zeida Mitsuhiro , Wieser Marco , Yoshida Toyokazu , Sugio Tsuyoshi , Nagasawa Toru 
Published: December 2019

ABSTRACT

Oxygen-sensitive gallic acid decarboxylase from
Pantoea
(formerly
Enterobacter
)
agglomerans
T71 was purified from a cell extract after stabilization by reducing agents. This enzyme has a molecular mass of approximately 320 kDa and consists of six identical subunits. It is highly specific for gallic acid. Gallic acid decarboxylase is unique among similar decarboxylases in that it requires iron as a cofactor, as shown by plasma emission spectroscopy (which revealed an iron content of 0.8 mol per mol of enzyme subunit), spectrophotometric analysis (absorption shoulders at 398 and 472 nm), and inhibition of the enzyme activity by 2,2′-bipyridyl,
o
-phenanthroline, and EDTA. Another interesting feature of this strain is the fact that it contains a tannase, which is used together with the gallic acid decarboxylase in a two-enzyme resting cell bioconversion to synthesize valuable pyrogallol from readily available tannic acid.
Assessment of Changes in Microbial Community Structure during Operation of an Ammonia Biofilter with Molecular Tools
Authors: Sakano Y. , Kerkhof L. 
Published: December 2019

ABSTRACT

Biofiltration has been used for two decades to remove odors and various volatile organic and inorganic compounds in contaminated off-gas streams. Although biofiltration is widely practiced, there have been few studies of the bacteria responsible for the removal of air contaminants in biofilters. In this study, molecular techniques were used to identify bacteria in a laboratory-scale ammonia biofilter. Both 16S rRNA and ammonia monooxygenase (
amoA
) genes were used to characterize the heterotrophic and ammonia-oxidizing bacteria collected from the biofilter during a 102-day experiment. The overall diversity of the heterotrophic microbial population appeared to decrease by 38% at the end of the experiment. The community structure of the heterotrophic population also shifted from predominantly members of two subdivisions of the
Proteobacteria
(the beta and gamma subdivisions) to members of one subdivision (the gamma subdivision). An overall decrease in the diversity of ammonia monooxygenase genes was not observed. However, a shift from groups dominated by organisms containing
Nitrosomonas
-like and
Nitrosospira
-like
amoA
genes to groups dominated by organisms containing only
Nitrosospira
-like
amoA
genes was observed. In addition, a new
amoA
gene was discovered. This new gene is the first freshwater
amoA
gene that is closely affiliated with
Nitrosococcus oceanus
and the particulate methane monooxygenase gene from the methane oxidizers belonging to the gamma subdivision of the
Proteobacteria
.
Purification and Genetic Characterization of Enterocin I from
Enterococcus faecium
6T1a, a Novel Antilisterial Plasmid-Encoded Bacteriocin Which Does Not Belong to the Pediocin Family of Bacteriocins
Authors: Floriano Belén , Ruiz-Barba José L. , Jiménez-Díaz Rufino 
Published: December 2019

ABSTRACT

Enterocin I (ENTI) is a novel bacteriocin produced by
Enterococcus faecium
6T1a, a strain originally isolated from a Spanish-style green olive fermentation. The bacteriocin is active against many olive spoilage and food-borne gram-positive pathogenic bacteria, including clostridia, propionibacteria, and
Listeria monocytogenes
. ENTI was purified to homogeneity by ammonium sulfate precipitation, binding to an SP-Sepharose fast-flow column, and phenyl-Sepharose CL-4B and C
2
/C
18
reverse-phase chromatography. The purification procedure resulted in a final yield of 954% and a 170,000-fold increase in specific activity. The primary structure of ENTI was determined by amino acid and nucleotide sequencing. ENTI consists of 44 amino acids and does not show significant sequence similarity with any other previously described bacteriocin. Sequencing of the
entI
structural gene, which is located on the 23-kb plasmid pEF1 of
E. faecium
6T1a, revealed the absence of a leader peptide at the N-terminal region of the gene product. A second open reading frame, ORF2, located downstream of
entI
, encodes a putative protein that is 72.7% identical to ENTI.
entI
and ORF2 appear to be cotranscribed, yielding an mRNA of ca. 0.35 kb. A gene encoding immunity to ENTI was not identified. However, curing experiments demonstrated that both enterocin production and immunity are conferred by pEF1.
Species-Specific Oligonucleotides for Enumeration of
Pseudomonas putida
F1,
Burkholderia
sp. Strain JS150, and
Bacillus subtilis
ATCC 7003 in Biodegradation Experiments
Authors: DuTeau Nancy M. , Rogers Julia D. , Bartholomay Christian T. , Reardon Kenneth F. 
Published: December 2019

ABSTRACT

Species-specific sequences were identified within the V4 variable region of 16S rRNA of two bacterial species capable of aromatic hydrocarbon metabolism,
Pseudomonas putida
F1 and
Burkholderia
sp. strain JS150, and a third,
Bacillus subtilis
ATCC 7003, that can function as a secondary degrader. Fluorescent in situ hybridization (FISH) with species-specific oligonucleotides was used for direct counting of these species throughout a phenol biodegradation experiment in batch culture. Traditional differential plate counting methods could not be used due to the similar metabolism and interactions of the primary degraders and difficulties in selecting secondary degraders in mixed culture. In contrast, the FISH method provided reliable quantitative results without interference from those factors.
Effect of Metabolites Produced by
Trichoderma harzianum
Biotypes and
Agaricus bisporus
on Their Respective Growth Radii in Culture
Authors: Mumpuni A. , Sharma H. S. S. , Brown Averil E. 
Published: December 2019

ABSTRACT

Trichoderma harzianum
biotypes Th1, Th2, and Th3 produced volatile metabolites in vitro which had similar fungistatic effects on the growth of
Agaricus bisporus
. Metabolites present in agar colonized by these strains also inhibited mycelial growth of
A. bisporus
, although the reduction in growth was less in the presence of metabolites produced by biotype Th2 than that in the presence of metabolites produced by Th1 or Th3.
A. bisporus
produced metabolites in liquid culture that inhibited the growth of Th1 and Th3 but stimulated the growth of Th2. A compound(s) responsible for the inhibition and stimulation was extracted from
A. bisporus
culture filtrate and from compost-grown fruit bodies with
n
-butanol, but the identity of the compound(s) was not determined. We suggest that the stimulation of Th2 by metabolites produced by
A. bisporus
and the relatively low level of inhibition of
A. bisporus
by Th2 facilitate colonization of compost by both fungi. However, as compost colonization reaches a maximum, a change in the competitive balance in favor of Th2 results in the inhibition of fruit body production by
A. bisporus
and the devastating green mold epidemics affecting mushroom production.
Optimization of Bacteriocin Release Protein (BRP)-Mediated Protein Release by
Escherichia coli
: Random Mutagenesis of the pCloDF13-Derived BRP Gene To Uncouple Lethality and Quasi-Lysis from Protein Release
Authors: van der Wal Fimme J. , Koningstein G. , ten Hagen C. M. , Oudega Bauke , Luirink Joen 
Published: December 2019

ABSTRACT

Bacteriocin release proteins (BRPs) can be used for the release of heterologous proteins from the
Escherichia coli
periplasm into the culture medium. However, high-level expression of BRP causes apparent lysis of the host cells in liquid cultures (quasi-lysis) and inhibition of growth on broth agar plates (lethality). To optimize BRP-mediated protein release, the pCloDF13 BRP gene was subjected to random mutagenesis by using PCR techniques. Mutated BRPs with a strongly reduced capacity to cause growth inhibition on broth agar plates were selected, analyzed by nucleotide sequencing, and further characterized by performing growth and release experiments in liquid cultures. A subset of these BRP derivatives did not cause quasi-lysis and had only a small effect on growth but still functioned in the release of the periplasmic protein β-lactamase and the periplasmic K88 molecular chaperone FaeE and in the release of the bacteriocin cloacin DF13 into the culture medium. These BRP derivatives can be more efficiently used for extracellular production of proteins by
E. coli
than can the original BRP.
Lacticin 3147, a Broad-Spectrum Bacteriocin Which Selectively Dissipates the Membrane Potential
Authors: McAuliffe Olivia , Ryan Maire P. , Ross R. Paul , Hill Colin , Breeuwer Pieter , Abee Tjakko 
Published: December 2019

ABSTRACT

Lacticin 3147 is a broad-spectrum bacteriocin produced by
Lactococcus lactis
subsp.
lactis
DPC3147 (M. P. Ryan, M. C. Rea, C. Hill, and R. P. Ross, Appl. Environ. Microbiol. 62:612–619, 1996). Partial purification of the bacteriocin by hydrophobic interaction chromatography and reverse-phase fast protein liquid chromatography revealed that two components are required for full activity. Lacticin 3147 is bactericidal against
L. lactis
,
Listeria monocytogenes
, and
Bacillus subtilis
; at low concentrations of the bacteriocin, bactericidal activity is enhanced when target cells are energized. This finding suggests that the presence of a proton motive force promotes the interaction of the bacteriocin with the cytoplasmic membrane, leading to the formation of pores at these low lacticin 3147 concentrations. These pores were shown to be selective for K
+
ions and inorganic phosphate. The loss of these ions resulted in immediate dissipation of the membrane potential and hydrolysis of internal ATP, leading to an eventual collapse of the pH gradient at the membrane and ultimately to cell death. Our results suggest that lacticin 3147 is a pore-forming bacteriocin which acts on a broad range of gram-positive bacteria.
Alcaligenes eutrophus
as a Bacterial Chromate Sensor
Authors: Peitzsch Nicola , Eberz Günther , Nies Dietrich H. 
Published: December 2019

ABSTRACT

In
Alcaligenes eutrophus
CH34, determinants encoding inducible resistance to chromate (
chr
) and to cobalt and nickel (
cnr
) are located adjacent to each other on plasmid pMOL28. To develop metal-sensing bacterial strains, a cloned part of plasmid pMOL28, which contains both determinants, was mutated with Tn
5-lacZ
. The
chr
::
lacZ
fusions were specifically induced by chromium;
cnr
was induced best by Ni
2+
but was also induced by Co
2+
, Mn
2+
, chromate, Cu
2+
, Cd
2+
, and Zn
2+
. The broad-host-range IncP1 plasmid pEBZ141, which contains a
chr
::
lux
fusion, was constructed.
A. eutrophus
AE104(pEBZ141), carrying a
chr
::
lux
transcriptional fusion, could be used as a biosensor for chromate when cultivated in glycerol as an optimal carbon source. Chromate and bichromate were the best inducers; induction by Cr
3+
was 10 times lower, and other ions induced only a little or not at all. Interactions among induction of the
chr
resistance determinant, chromate reduction, chromate accumulation, and the sulfate concentration of the growth medium were demonstrated.
Characterization of Marine Temperate Phage-Host Systems Isolated from Mamala Bay, Oahu, Hawaii
Authors: Jiang Sunny C. , Kellogg Christina A. , Paul John H. 
Published: December 2019

ABSTRACT

To understand the ecological and genetic role of viruses in the marine environment, it is critical to know the infectivity of viruses and the types of interactions that occur between marine viruses and their hosts. We isolated four marine phages from turbid plaques by using four indigenous bacterial hosts obtained from concentrated water samples from Mamala Bay, Oahu, Hawaii. Two of the rod-shaped bacterial hosts were identified as
Sphingomonas paucimobilis
and
Flavobacterium
sp. All of the phage isolates were tailed phages and contained double-stranded DNA. Two of the phage isolates had morphologies typical of the family
Siphoviridae
, while the other two belonged to the families
Myoviridae
and
Podoviridae
. The head diameters of these viruses ranged from 47 to 70.7 nm, and the tail lengths ranged from 12 to 146 nm. The burst sizes ranged from 7.8 to 240 phage/bacterial cell, and the genome sizes, as determined by restriction digestion, ranged from 36 to 112 kb. The members of the
Siphoviridae
, T-φHSIC, and T-φD0, and the member of the
Myoviridae
, T-φD1B, were found to form lysogenic associations with their bacterial hosts, which were isolated from the same water samples. Hybridization of phage T-φHSIC probe with lysogenic host genomic DNA was observed in dot blot hybridization experiments, indicating that prophage T-φHSIC was integrated within the host genome. These phage-host systems are available for use in studies of marine lysogeny and transduction.