bluuebunny/crossref_metadata_2025_split huggingface dataset:
Heat Shock Treatment Increases the Frequency of Lossof an Erythromycin Resistance-Encoding Transposable Element from theChromosome of
Lactobacillus crispatus
CHCC3692
Authors: Strøman Per , Müller Christina C. , Sørensen Kim I. 
Published: December 2003

ABSTRACT

A
3,165-bp chromosomally integrated transposon, designatedTn
3692
, of the gram-positive strain
Lactobacillus
crispatus
CHCC3692 contains an
erm
(B) gene
conferring resistance to erythromycin at concentrations of up to 250μ
g/ml. Loss of this resistance can occur spontaneously, but the
rate is substantially increased by heat shock treatment. Heat shock
treatment at 60°C resulted in an almost 40-fold increase in the
frequency of erythromycin-sensitive cells (erythromycin MIC, 0.047μ
g/ml). The phenotypic change was followed by a dramatic
increase in transcription of the transposase gene and the concomitant
loss of an approximately 2-kb DNA fragment carrying the
erm
(B)
gene from the 3,165-bp
erm
transposon. In cells that were not
subjected to heat shock, transcription of the transposase gene was not
detectable. The upstream sequence of the transposase gene did not show
any homology to known heat shock promoters in the gene data bank.
Significant homology (>99%) was observed between the
erythromycin resistance-encoding gene from
L. crispatus
CHCC3692 and the
erm
(B) genes from other gram-positive
bacteria, such as
Streptococcus agalactiae
,
Streptococcus
pyogenes
,
Enterococcus faecium
, and
Lactobacillus
reuteri
, which strongly indicates a common origin of the
erm
(B) gene for these species. The transposed DNA element was
not translocated to other parts of the genome of CHCC3692, as
determining by Southern blotting, PCR analysis, and DNA sequencing. No
other major aberrations were observed, as judged by colony morphology,
growth performance of the strain, and pulsed-field gel electrophoresis.
These observations suggest that heat shock treatment could be used as a
tool for the removal of unwanted antibiotic resistance genes harbored
in transposons flanked by insertion sequence elements or transposases
in lactic acid bacteria used for animal and human food
production.
Assessment of an Enterovirus Sewage SurveillanceSystem by Comparison of Clinical Isolates with Sewage Isolatesfrom Milwaukee, Wisconsin, Collected August 1994 toDecember2002
Authors: Sedmak Gerald , Bina David , MacDonald Jeffrey 
Published: December 2003

ABSTRACT
The
quantity and serotypes of enteroviruses (EVs) in the influent of a
local sewage treatment plant were compared to local clinical EV cases
to determine if testing of sewage is adequate for an EV surveillance
system. The study was carried out from August 1994 to December 2002.
Monthly influent specimens were processed by organic flocculation, and
dilutions of concentrate were inoculated onto a number of different
cell types for virus isolation. EVs were detected in 88 of 100 monthly
influent samples. Sewage EV titers were calculated by using software
provided by the U.S. Environmental Protection Agency for
most-probable-number determination. All 1,068 sewage EV isolates were
further grouped (echovirus, coxsackievirus B, coxsackievirus A, or
poliovirus) by cell culture host range analysis (growth pattern of
isolates on passage to seven cell lines), and 39.0% of the 1,022
EV isolates categorized as non-poliovirus EVs were specifically
serotyped. For clinical cases, primary virus isolation tests were
performed on specimens submitted by local hospitals and EV isolates
submitted by hospitals were serotyped. Clinical EVs were documented for
81 of the 100 months studied. In all, 694 EV isolates from clinical
cases were serotyped. Annually, between 4 and 11 different serotypes of
non-poliovirus EVs were identified in sewage and from 9 to 19 different
non-poliovirus EV serotypes were identified from clinical specimens.
Usually, the most commonly detected sewage EV serotypes were similar to
the most commonly detected clinical serotypes; e.g., for 1997,
echovirus 6 accounted for 53.1% of the typed sewage isolates and
39.4% of the clinical infections, while in 1998, echovirus 30
accounted for 50.0 and 46.1%, respectively. In 1999,
60.3% of the EVs from clinical cases and 79.7% of the
sewage isolates were echovirus 11; in 2000, 33.3% of the EVs
from clinical cases and 40.7% of the sewage isolates were
coxsackievirus B5; and in 2001, 44.1% of the EVs from clinical
cases and 36.2% of the sewage isolates were echovirus 13. Annual
peaks of both sewage EV titers and clinical cases occurred in late
summer or early fall. In some years, early spring sewage EVs
portended some of the EVs that would predominate clinically
during the following
summer.
Inoculum Size Influences Bacterial CrossContamination betweenSurfaces
Authors: Montville R. , Schaffner D. W. 
Published: December 2003

ABSTRACT

Many
factors have been shown to influence bacterial transfer between
surfaces, including surface type, bacterial species, moisture level,
pressure, and friction, but the effect of inoculum size on bacterial
transfer has not yet been established. Bacterial cross contamination
rates during performance of common food service tasks were previously
determined in our laboratory using nalidixic acid-resistant
Enterobacter aerogenes
. Eight different transfer rates were
determined, each involving a minimum of 30 volunteers. The influence of
source inoculum level on the percentage of bacteria transferred
(percent transfer rates) and log
10
CFU per recipient surface
was determined using statistical analysis. The effect of inoculum size
on transfer rate was highly statistically significant (
P
< 0.0001) for all transfer rate data combined (352
observations) and for each individual cross contamination rate, except
for data on contamination via transfer from chicken to hand through a
glove barrier (
P
= 0.1643). Where inoculum size on the
source was greater, transfer rates were lower, and where inoculum size
on the source was less, transfer rates were higher. The negative linear
trend was more obvious for activities that had a larger range of
inoculum sizes on the source surface. This phenomenon has serious
implications for research seeking to determine bacterial cross
contamination rates, since the different transfer efficiencies that
were previously shown to be associated with certain activities may
actually be the result of differing initial inoculum levels. The
initial inoculum size on the source and the amount of bacteria
transferred must both be considered to accurately determine bacterial
transfer
rates.
Functional Characterization of a Composite BacteriocinLocus from Malt Isolate
Lactobacillus sakei
5
Authors: Vaughan Anne , Eijsink Vincent G. H. , van Sinderen Douwe 
Published: December 2003

ABSTRACT

Lactobacillus
sakei
5, isolated from malted barley, produces three bacteriocins.
Genetic and functional analysis of the purified bacteriocins showed
that this strain produces a plasmid-encoded bacteriocin that is
identical to sakacin P, as well as two novel, chromosomally encoded
bacteriocins, which were designated sakacin T and sakacin X. The
structural genes specifying sakacin T and sakacin X are part of the
sakacin TX
locus, which consists of two adjacent but
divergently oriented gene clusters. The first gene cluster includes
stxP
,
stxR
,
stxK
, and
stxT
, which,
based on functional and comparative sequence analysis, are believed to
encode an inducing peptide and proteins involved in regulation and
secretion of these bacteriocins. The second gene cluster includes the
structural and immunity genes for sakacin T, a class IIb two-peptide
bacteriocin composed of SakT
α
and
SakT
β
, and sakacin X, a class IIa bacteriocin.
Interestingly, a so-called transport accessory protein was absent from
the locus, and based on our results it appears that a dedicated
accessory protein is not required for processing and transport of
sakacin T and sakacin
X.
BacterialSynergism or Antagonism in a Gel CassetteSystem
Authors: Tsigarida Eirini , Boziaris Ioannis S. , Nychas George-John E. 
Published: December 2003

ABSTRACT

The
growth and the metabolic activity of
Shewanella putrfaciens
,
Brochothrix thermosphacta
, and
Pseudomonas
sp., when
cultured individually or in all possible combinations in gel cassettes
system supplemented with 0.1% glucose at 5°C, were
investigated. The overall outcome was that the coexistence of the
above-mentioned microorganisms affected not only each growth rate but
also their type of metabolic end products compared to the control
cultures. These effects were varied and depended on the selection of
the combination of the tested bacteria. For example, the growth of
Pseudomonas
sp. strains cocultured with either
B.
thermosphacta
or
S. putrefaciens
strains resulted in
different effects: a promoting one for the first and an inhibitory one
for the second. Moreover, the production of formic acid and two
unidentified organic acids (peaks a and b) was characteristic in all
cases in which
S. putrefaciens
was
cultured.
Laboratory Cultivation of Widespread and PreviouslyUncultured SoilBacteria
Authors: Joseph Shayne J. , Hugenholtz Philip , Sangwan Parveen , Osborne Catherine A. , Janssen Peter H. 
Published: December 2003

ABSTRACT

Most
soil bacteria belong to family-level phylogenetic groups with few or no
known cultivated representatives. We cultured a collection of 350
isolates from soil by using simple solid media in petri dishes. These
isolates were assigned to 60 family-level groupings in nine bacterial
phyla on the basis of a comparative analysis of their 16S rRNA genes.
Ninety-three (27%) of the isolates belonged to 20 as-yet-unnamed
family-level groupings, many from poorly studied bacterial classes and
phyla. They included members of subdivisions 1, 2, 3, and 4 of the
phylum
Acidobacteria
, subdivision 3 of the phylum
Verrucomicrobia
, subdivision 1 of the phylum
Gemmatimonadetes
, and subclasses
Acidimicrobidae
and
Rubrobacteridae
of the phylum
Actinobacteria
. In
addition, members of 10 new family-level groupings of subclass
Actinobacteridae
of the phylum
Actinobacteria
and
classes
Alphaproteobacteria
,
Betaproteobacteria
, and
Gammaproteobacteria
of the phylum
Proteobacteria
were
obtained. The high degree of phylogenetic novelty and the number of
isolates affiliated with so-called unculturable groups show that simple
cultivation methods can still be developed further to obtain laboratory
cultures of many phylogenetically novel soil
bacteria.
Microbial Communities Associated with GeologicalHorizons in Coastal Subseafloor Sediments from the Sea ofOkhotsk
Authors: Inagaki Fumio , Suzuki Masae , Takai Ken , Oida Hanako , Sakamoto Tatsuhiko , Aoki Kaori , Nealson Kenneth H. , Horikoshi Koki 
Published: December 2003

ABSTRACT

Microbial
communities from a subseafloor sediment core from the southwestern Sea
of Okhotsk were evaluated by performing both cultivation-dependent and
cultivation-independent (molecular) analyses. The core, which extended
58.1 m below the seafloor, was composed of pelagic clays with
several volcanic ash layers containing fine pumice grains. Direct cell
counting and quantitative PCR analysis of archaeal and bacterial 16S
rRNA gene fragments indicated that the bacterial populations in the ash
layers were approximately 2 to 10 times larger than those in the clays.
Partial sequences of 1,210 rRNA gene clones revealed that there were
qualitative differences in the microbial communities from the two
different types of layers. Two phylogenetically distinct archaeal
assemblages in the
Crenarchaeota
, the miscellaneous
crenarchaeotic group and the deep-sea archaeal group, were the most
predominant archaeal 16S rRNA gene components in the ash layers and the
pelagic clays, respectively. Clones of 16S rRNA gene sequences from
members of the gamma subclass of the class
Proteobacteria
dominated the ash layers, whereas sequences from members of the
candidate division OP9 and the green nonsulfur bacteria dominated the
pelagic clay environments. Molecular (16S rRNA gene sequence) analysis
of 181 isolated colonies revealed that there was regional proliferation
of viable heterotrophic mesophiles in the volcanic ash layers, along
with some gram-positive bacteria and actinobacteria. The porous ash
layers, which ranged in age from tens of thousands of years to hundreds
of thousands of years, thus appear to be discrete microbial habitats
within the coastal subseafloor clay sediment, which are capable of
harboring microbial communities that are very distinct from the
communities in the more abundant pelagic
clays.
Targeting Methanopterin Biosynthesis ToInhibitMethanogenesis
Authors: Dumitru Razvan , Palencia Hector , Schroeder Scott D. , DeMontigny Bree A. , Takacs James M. , Rasche Madeline E. , Miner Jess L. , Ragsdale Stephen W. 
Published: December 2003

ABSTRACT

This
paper describes the design, synthesis, and successful employment of
inhibitors of
4-(β-
d
-ribofuranosyl)aminobenzene-5′-phosphate
(RFA-P) synthase, which catalyzes the first committed step in the
biosynthesis of methanopterin, to specifically halt the growth of
methane-producing microbes. RFA-P synthase catalyzes the first step in
the synthesis of tetrahydromethanopterin, a key cofactor required for
methane formation and for one-carbon transformations in methanogens. A
number of inhibitors, which are N-substituted derivatives of
p
-aminobenzoic acid (pABA), have been synthesized and their
inhibition constants with RFA-P synthase have been determined. Based on
comparisons of the inhibition constants among various inhibitors, we
propose that the pABA binding site in RFA-P synthase has a relatively
large hydrophobic pocket near the amino group. These enzyme-targeted
inhibitors arrest the methanogenesis and growth of pure cultures of
methanogens. Supplying pABA to the culture relieves the inhibition,
indicating a competitive interaction between pABA and the inhibitor at
the cellular target, which is most likely RFAP synthase. The inhibitors
do not adversely affect the growth of pure cultures of the bacteria
(acetogens) that play a beneficial role in the rumen. Inhibitors added
to dense ruminal fluid cultures (artificial rumena) halt
methanogenesis; however, they do not inhibit volatile fatty acid (VFA)
production and, in some cases, VFA levels are slightly elevated in the
methanogenesis-inhibited cultures. We suggest that inhibiting
methanopterin biosynthesis could be considered in strategies to
decrease anthropogenic methane emissions, which could have an
environmental benefit since methane is a potent greenhouse
gas.
Transduction of Porcine Enteropathogenic
Escherichia coli
with a Derivative of a Shiga Toxin 2-EncodingBacteriophage in a Porcine Ligated Ileal LoopSystem
Authors: Tóth István , Schmidt Herbert , Dow Mohamed , Malik Anna , Oswald Eric , Nagy Béla 
Published: December 2003

ABSTRACT

In
this study, we have investigated the ability of detoxified Shiga toxin
(Stx)-converting bacteriophages Φ3538
(Δ
stx
2
::
cat
)
(H. Schmidt et al., Appl. Environ. Microbiol. 65:3855-3861,
1999) and H-19B::Tn
10d-bla
(D.
W. Acheson et al., Infect. Immun. 66:4496-4498, 1998) to
lysogenize enteropathogenic
Escherichia coli
(EPEC) strains in
vivo. We were able to transduce the porcine EPEC strain 1390 (O45) withΦ
3538
(Δ
stx
2
::
cat
)
in porcine ligated ileal loops but not the human EPEC prototype strain
E2348/69 (O127). Neither strain 1390 nor strain E2348/69 was
lysogenized under these in vivo conditions when
E. coli
K-12
containing H-19B::Tn
10d-bla
was used as
the
stx1
phage donor. The repeated success in the in vivo
transduction of an Stx2-encoding phage to a porcine EPEC strain in pig
loops was in contrast to failures in the in vitro trials with these and
other EPEC strains. These results indicate that in vivo conditions are
more effective for transduction of Stx2-encoding phages than in vitro
conditions.
Molecular andCulture-Based Analyses of Aerobic Carbon Monoxide OxidizerDiversity†
Authors: King Gary M. 
Published: December 2003

ABSTRACT

Isolates
belonging to six genera not previously known to oxidize CO were
obtained from enrichments with aquatic and terrestrial plants. DNA from
these and other isolates was used in PCR assays of the gene for the
large subunit of carbon monoxide dehydrogenase (
coxL
).
CoxL
and putative
coxL
fragments were amplified from
known CO oxidizers (e.g.,
Oligotropha carboxidovorans
and
Bradyrhizobium japonicum
), from novel CO-oxidizing isolates
(e.g.,
Aminobacter
sp. strain COX,
Burkholderia
sp.
strain LUP,
Mesorhizobium
sp. strain NMB1,
Stappia
strains M4 and M8,
Stenotrophomonas
sp. strain LUP, and
Xanthobacter
sp. strain COX), and from several well-known
isolates for which the capacity to oxidize CO is reported here for the
first time (e.g.,
Burkholderia fungorum
LB400,
Mesorhizobium loti
,
Stappia stellulata
, and
Stappia aggregata
). PCR products from several taxa, e.g.,
O. carboxidovorans
,
B. japonicum
, and
B.
fungorum
, yielded sequences with a high degree
(>99.6%) of identity to those in GenBank or genome
databases. Aligned sequences formed two phylogenetically distinct
groups. Group OMP contained sequences from previously known
CO oxidizers, including
O. carboxidovorans
and
Pseudomonas
thermocarboxydovorans
, plus a number of closely
related sequences. Group BMS was dominated by putative
coxL
sequences from genera in the
Rhizobiaceae
and otherα
-
Proteobacteria
. PCR analyses revealed that many CO
oxidizers contained two
coxL
sequences, one from each group.
CO oxidation by
M. loti
, for which whole-genome
sequencing has revealed a single BMS-group putative
coxL
gene,
strongly supports the notion that BMS sequences represent functional CO
dehydrogenase proteins that are related to but distinct from previously
characterized aerobic CO
dehydrogenases.
Uptake ofCarbon Monoxide and Hydrogen at Environmentally Relevant Concentrationsby Mycobacteria†
Authors: King Gary M. 
Published: December 2003

ABSTRACT

Liquid
culture assays revealed a previously unreported capacity
for
Mycobacterium bovis
BCG,
M. gordonae
,
and
M. marinum
to oxidize CO and for
M
.
smegmatis
to consume molecular hydrogen.
M
.
bovis
BCG,
M. gordonae
,
M
.
smegmatis
, and
M. tuberculosis
H37Ra oxidized CO at
environmentally relevant concentrations (<50 ppm);
H
2
oxidation by
M. gordonae
and
M. smegmatis
also occurred at environmentally
relevant concentrations (<10 ppm). CO was not consumed by
M. avium
or
M. microti
, although
the latter appeared to possess CO dehydrogenase (CODH) genes based on
PCR results with primers designed for the CODH large subunit,
coxL. M. smegmatis
and
M
.
gordonae
oxidized CO under suboxic (10 and 1%
atmospheric oxygen) and anoxic conditions in the presence of nitrate;
no oxidation occurred under anoxic conditions without nitrate. Similar
results were obtained for H
2
oxidation by
M
.
smegmatis
. Phylogenetic analyses of
coxL
PCR products
indicated that mycobacterial sequences form a subclade distinct from
that of other bacterial
coxL
, with limited differentiation
among fast- and slow-growing
strains.
Characterization of the
argA
Gene Requiredfor Arginine Biosynthesis and Syringomycin Production by
Pseudomonas syringae
pv.syringae
Authors: Lu Shi-En , Soule Jonathan D. , Gross Dennis C. 
Published: December 2003

ABSTRACT

Two
types of necrosis-inducing lipodepsipeptide toxins, called syringomycin
and syringopeptin, are major virulence factors of
Pseudomonas
syringae
pv. syringae strain B301D. A previous study showed that a
locus, called
syrA
, was required for both syringomycin
production and plant pathogenicity, and the
syrA
locus was
speculated to encode a regulator of toxin production. In this study,
sequence analysis of the 8-kb genomic DNA fragment that complements the
syrA
phenotype revealed high conservation among a broad
spectrum of fluorescent pseudomonads. The putative protein encoded by
open reading frame 4 (ORF4) (1,299 bp) in the
syrA
locus
region exhibited 85% identity to ArgA, which is involved in
arginine biosynthesis in
Pseudomonas aeruginosa
. Growth of
strain W4S2545, the
syrA
mutant, required supplementation of N
minimal medium with arginine. Similarly, syringomycin production of
syrA
mutant W4S2545 was restored by the addition of arginine
to culture media. Furthermore, the insertion of Tn
5
in the
genome of the
syrA
mutant W4S2545 was localized between
nucleotides 146 and 147 in ORF4, and syringomycin production was
complemented in
trans
with the wild-type DNA fragment
containing intact ORF4. These results demonstrate that the
syrA
locus is the
argA
gene of
P. syringae
pv. syringae and that
argA
is directly involved in arginine
biosynthesis and therefore indirectly affects syringomycin production
because of arginine
deficiency.
Abilityof
Lactococcus lactis
To Export Viral CapsidAntigens: a Crucial Step for Development of LiveVaccines
Authors: Dieye Yakhya , Hoekman Arjan J. W. , Clier Florence , Juillard Vincent , Boot Hein J. , Piard Jean-Christophe 
Published: December 2003

ABSTRACT

Thefood grade bacterium
Lactococcus lactis
is a
potential vehicle for protein delivery in the gastrointestinal tract.
As a model, we constructed lactococcal strains producing antigens of
infectious bursal disease virus (IBDV). IBDV infects chickens and
causes depletion of B-lymphoid cells in the bursa of Fabricius and
subsequent immunosuppression, morbidity, or acute mortality. The two
major IBDV antigens, i.e., VP2 and VP3, that form the viral capsid were
expressed and targeted to the cytoplasm, the cell wall, or the
extracellular compartment of
L. lactis
. Whereas VP3
was successfully targeted to the three compartments by the use of
relevant expression and export vectors, VP2 was recalcitrant to export,
thus confirming the difficulty of translocating naturally nonsecreted
proteins across the bacterial membrane. This defect could be partly
overcome by fusing VP2 to a naturally secreted protein (the
staphylococcal nuclease Nuc) that carried VP2 through the membrane.
Lactococcal strains producing Nuc-VP2 and VP3 in various bacterial
compartments were administered orally to chickens. The chickens did not
develop any detectable immune response against VP2 and VP3 but did
exhibit an immune response against Nuc when Nuc-VP2 was anchored to the
cell wall of
lactococci.
Quantitative Real-Time PCR for Determination ofMicrocystin Synthetase E Copy Numbers forMicrocystisandAnabaenainLakes
Authors: Vaitomaa Jaana , Rantala Anne , Halinen Katrianna , Rouhiainen Leo , Tallberg Petra , Mokelke Lena , Sivonen Kaarina 
Published: December 2003

ABSTRACTCyanobacterial mass occurrences in freshwater lakes are generally formed byAnabaena,Microcystis, andPlanktothrix, which may produce cyclic heptapeptide hepatotoxins, microcystins. Thus far, identification of the most potent microcystin producer in a lake has not been possible due to a lack of quantitative methods. The aim of this study was to identify the microcystin-producing genera and to determine the copy numbers of microcystin synthetase gene E (mcyE) in Lake Tuusulanjärvi and Lake Hiidenvesi in Finland by quantitative real-time PCR. The microcystin concentrations and cyanobacterial cell densities of these lakes were also determined. The microcystin concentrations correlated positively with the sum ofMicrocystisandAnabaena mcyEcopy numbers from both Lake Tuusulanjärvi and Lake Hiidenvesi, indicating thatmcyEgene copy numbers can be used as surrogates for hepatotoxicMicrocystisandAnabaena. The main microcystin producer in Lake Tuusulanjärvi wasMicrocystisspp., since averageMicrocystis mcyEcopy numbers were >30 times more abundant than those ofAnabaena. Lake Hiidenvesi seemed to contain both nontoxic and toxicAnabaenaas well as toxicMicrocystisstrains. Identifying the most potent microcystin producer in a lake could be valuable for designing lake restoration strategies, among other uses.