bluuebunny/crossref_metadata_2025_split huggingface dataset:
Campylobacter troglodytis
sp. nov., Isolated from Feces of Human-Habituated Wild Chimpanzees (
Pan troglodytes schweinfurthii
) in Tanzania
Authors: Kaur Taranjit , Singh Jatinder , Huffman Michael A. , Petrželková Klára J. , Taylor Nancy S. , Xu Shilu , Dewhirst Floyd E. , Paster Bruce J. , Debruyne Lies , Vandamme Peter , Fox James G. 
Published: January 2011

ABSTRACT

The transmission of simian immunodeficiency and Ebola viruses to humans in recent years has heightened awareness of the public health significance of zoonotic diseases of primate origin, particularly from chimpanzees. In this study, we analyzed 71 fecal samples collected from 2 different wild chimpanzee (
Pan troglodytes
) populations with different histories in relation to their proximity to humans.
Campylobacter
spp. were detected by culture in 19/56 (34%) group 1 (human habituated for research and tourism purposes at Mahale Mountains National Park) and 0/15 (0%) group 2 (not human habituated but propagated from an introduced population released from captivity over 30 years ago at Rubondo Island National Park) chimpanzees, respectively. Using 16S rRNA gene sequencing, all isolates were virtually identical (at most a single base difference), and the chimpanzee isolates were most closely related to
Campylobacter helveticus
and
Campylobacter upsaliensis
(94.7% and 95.9% similarity, respectively). Whole-cell protein profiling, amplified fragment length polymorphism analysis of genomic DNA,
hsp60
sequence analysis, and determination of the mol% G+C content revealed two subgroups among the chimpanzee isolates. DNA-DNA hybridization experiments confirmed that both subgroups represented distinct genomic species. In the absence of differential biochemical characteristics and morphology and identical 16S rRNA gene sequences, we propose to classify all isolates into a single novel nomenspecies,
Campylobacter troglodytis
, with strain MIT 05-9149 as the type strain; strain MIT 05-9157 is suggested as the reference strain for the second
C. troglodytis
genomovar. Further studies are required to determine whether the organism is pathogenic to chimpanzees and whether this novel
Campylobacter
colonizes humans and causes enteric disease.
Strong and Consistently Synergistic Inactivation of Spores of Spoilage-AssociatedBacillusandGeobacillusspp. by High Pressure and Heat Compared with Inactivation by Heat Alone
Authors: Olivier S. A. , Bull M. K. , Stone G. , van Diepenbeek R. J. , Kormelink F. , Jacops L. , Chapman B. 
Published: January 2011

ABSTRACTThe inactivation of spores of four low-acid food spoilage organisms by high pressure thermal (HPT) and thermal-only processing was compared on the basis of equivalent thermal lethality calculated at a reference temperature of 121.1°C (Fz121.1°C, 0.1 MPa or 600 MPa) and characterized as synergistic, not different or protective. In addition, the relative resistances of spores of the different spoilage microorganisms to HPT processing were compared. Processing was performed and inactivation was compared in both laboratory and pilot scale systems and in model (diluted) and actual food products. Where statistical comparisons could be made, at least 4 times and up to around 190 times more inactivation (log10reduction/minute atFTz121.1°C) of spores ofBacillus amyloliquefaciens,Bacillus sporothermodurans, andGeobacillus stearothermophiluswas achieved using HPT, indicating a strong synergistic effect of high pressure and heat.Bacillus coagulansspores were also synergistically inactivated in diluted and undiluted Bolognese sauce but were protected by pressure against thermal inactivation in undiluted cream sauce. Irrespective of the response characterization,B. coagulansandB. sporothermoduranswere identified as the most HPT-resistant isolates in the pilot scale and laboratory scale studies, respectively, andG. stearothermophilusas the least in both studies and all products. This is the first study to comprehensively quantitatively characterize the responses of a range of spores of spoilage microorganisms as synergistic (or otherwise) using an integrated thermal-lethality approach (FTz). The use of theFTzapproach is ultimately important for the translation of commercial minimum microbiologically safe and stable thermal processes to HPT processes.
Indirect Modulation of the Intracellular c-Di-GMP Level in
Shewanella oneidensis
MR-1 by MxdA
Authors: Rakshe Shauna , Leff Maija , Spormann Alfred M. 
Published: January 2011

ABSTRACT

The GGDEF domain protein MxdA, which is important for biofilm formation in
Shewanella oneidensis
MR-1, was hypothesized to possess diguanylate cyclase activity. Here, we demonstrate that while MxdA controls the cellular level of c-di-GMP in
S. oneidensis
, it modulates the c-di-GMP pool indirectly.
Proteomic and Transcriptomic Elucidation of the Mutant
Ralstonia eutropha
G
+
1 with Regard to Glucose Utilization
Authors: Raberg Matthias , Peplinski Katja , Heiss Silvia , Ehrenreich Armin , Voigt Birgit , Döring Christina , Bömeke Mechthild , Hecker Michael , Steinbüchel Alexander 
Published: January 2011

ABSTRACT

By taking advantage of the available genome sequence of
Ralstonia eutropha
H16, glucose uptake in the UV-generated glucose-utilizing mutant
R. eutropha
G
+
1 was investigated by transcriptomic and proteomic analyses. Data revealed clear evidence that glucose is transported by a usually
N
-acetylglucosamine-specific phosphotransferase system (PTS)-type transport system, which in this mutant is probably overexpressed due to a derepression of the encoding
nag
operon by an identified insertion mutation in gene H16_A0310 (
nagR
). Furthermore, a missense mutation in
nagE
(membrane component EIICB), which yields a substitution of an alanine by threonine in NagE and may additionally increase glucose uptake, was identified. Phosphorylation of glucose is subsequently mediated by NagF (cytosolic PTS component EIIA-HPr-EI) or glucokinase (GlK), respectively. The inability of the defined deletion mutant
R. eutropha
G
+
1 Δ
nagFEC
to utilize glucose strongly confirms this finding. In addition, secondary effects of glucose, which is now intracellularly available as a carbon source, on the metabolism of the mutant cells in the stationary growth phase occurred: intracellular glucose degradation is stimulated by the stronger expression of enzymes involved in the 2-keto-3-deoxygluconate 6-phosphate (KDPG) pathway and in subsequent reactions yielding pyruvate. The intermediate phosphoenolpyruvate (PEP) in turn supports further glucose uptake by the Nag PTS. Pyruvate is then decarboxylated by the pyruvate dehydrogenase multienzyme complex to acetyl coenzyme A (acetyl-CoA), which is directed to poly(3-hydroxybutyrate). The polyester is then synthesized to a greater extent, as also indicated by the upregulation of various enzymes of poly-β-hydroxybutyrate (PHB) metabolism. The larger amounts of NADPH required for PHB synthesis are delivered by significantly increased quantities of proton-translocating NAD(P) transhydrogenases. The current study successfully combined transcriptomic and proteomic investigations to unravel the phenotype of this hitherto-undefined glucose-utilizing mutant.
Prevalence, Development, and Molecular Mechanisms of Bacteriocin Resistance in
Campylobacter
Authors: Hoang Ky Van , Stern Norman J. , Saxton Arnold M. , Xu Fuzhou , Zeng Ximin , Lin Jun 
Published: January 2011

ABSTRACT

Bacteriocins (BCNs) are antimicrobial peptides produced by bacteria with narrow or broad spectra of antimicrobial activity. Recently, several unique anti-
Campylobacter
BCNs have been identified from commensal bacteria isolated from chicken intestines. These BCNs dramatically reduced
C. jejuni
colonization in poultry and are being directed toward on-farm control of
Campylobacter
. However, no information concerning prevalence, development, and mechanisms of BCN resistance in
Campylobacter
exists. In this study, susceptibilities of 137
C. jejuni
isolates and 20
C. coli
isolates to the anti-
Campylobacter
BCNs OR-7 and E-760 were examined. Only one
C. coli
strain displayed resistance to the BCNs (MIC, 64 μg/ml), while others were susceptible, with MICs ranging from 0.25 to 4 μg/ml. The
C. coli
mutants resistant to BCN OR-7 also were obtained by
in vitro
selection, but all displayed only low-level resistance to OR-7 (MIC, 8 to 16 μg/ml). The acquired BCN resistance in
C. coli
could be transferred at intra- and interspecies levels among
Campylobacter
strains by biphasic natural transformation. Genomic examination of the OR-7-resistant mutants by using DNA microarray and random transposon mutagenesis revealed that the multidrug efflux pump CmeABC contributes to both intrinsic resistance and acquired resistance to the BCNs. Altogether, this study represents the first report of and a major step forward in understanding BCN resistance in
Campylobacter
, which will facilitate the development of effective BCN-based strategies to reduce the
Campylobacter
loads in poultry.
Iodide Accumulation by Aerobic Bacteria Isolated from Subsurface Sediments of a
129
I-Contaminated Aquifer at the Savannah River Site, South Carolina
Authors: Li Hsiu-Ping , Brinkmeyer Robin , Jones Whitney L. , Zhang Saijin , Xu Chen , Schwehr Kathy A. , Santschi Peter H. , Kaplan Daniel I. , Yeager Chris M. 
Published: January 2011

ABSTRACT

129
I is of major concern because of its mobility in the environment, excessive inventory, toxicity (it accumulates in the thyroid), and long half-life (∼16 million years). The aim of this study was to determine if bacteria from a
129
I-contaminated oxic aquifer at the F area of the U.S. Department of Energy's Savannah River Site, SC, could accumulate iodide at environmentally relevant concentrations (0.1 μM I
−
). Iodide accumulation capability was found in 3 out of 136 aerobic bacterial strains isolated from the F area that were closely related to
Streptomyces
/
Kitasatospora
spp.,
Bacillus mycoides
, and
Ralstonia/Cupriavidus
spp. Two previously described iodide-accumulating marine strains, a
Flexibacter aggregans
strain and an
Arenibacter troitsensis
strain, accumulated 2 to 50% total iodide (0.1 μM), whereas the F-area strains accumulated just 0.2 to 2.0%. Iodide accumulation by FA-30 was stimulated by the addition of H
2
O
2
, was not inhibited by chloride ions (27 mM), did not exhibit substrate saturation kinetics with regard to I
−
concentration (up to 10 μM I
−
), and increased at pH values of <6. Overall, the data indicate that I
−
accumulation likely results from electrophilic substitution of cellular organic molecules. This study demonstrates that readily culturable, aerobic bacteria of the F-area aquifer do not accumulate significant amounts of iodide; however, this mechanism may contribute to the long-term fate and transport of
129
I and to the biogeochemical cycling of iodine over geologic time.
Functional and Structural Microbial Diversity in Organic and Conventional Viticulture: Organic Farming Benefits Natural Biocontrol Agents
Authors: Schmid Florian , Moser Gerit , Müller Henry , Berg Gabriele 
Published: January 2011

ABSTRACT

Statistically significant differences in the structure and function of above-ground grapevine-associated microorganisms from organically and conventionally managed vineyards were found.
Aureobasidium pullulans
, a copper-detoxifying fungus and biocontrol agent, plays a key role in explaining these differences. The black fungus was strongly enriched in the communities of organically managed plants and yielded a higher indigenous antiphytopathogenic potential.
LuxS Coexpression Enhances Yields of Recombinant Proteins in
Escherichia coli
in Part through Posttranscriptional Control of GroEL
Authors: Tsao Chen-Yu , Wang Liang , Hashimoto Yoshifumi , Yi Hyunmin , March John C. , DeLisa Matthew P. , Wood Thomas K. , Valdes James J. , Bentley William E. 
Published: January 2011

ABSTRACT

Cell-to-cell communication, or quorum sensing (QS), enables cell density-dependent regulation of bacterial gene expression which can be exploited for the autonomous-signal-guided expression of recombinant proteins (C. Y. Tsao, S. Hooshangi, H. C. Wu, J. J. Valdes, and W. E. Bentley, Metab. Eng. 12:291-297, 2010). Earlier observations that the metabolic potential of
Escherichia coli
is conveyed via the QS signaling molecule autoinducer-2 (AI-2) suggested that the capacity for protein synthesis could also be affected by AI-2 signaling (M. P. DeLisa, J. J. Valdes, and W. E. Bentley, J. Bacteriol. 183:2918-2928, 2001). In this work, we found that simply adding conditioned medium containing high levels of AI-2 at the same time as inducing the synthesis of recombinant proteins doubled the yield of active product. We have hypothesized that AI-2 signaling “conditions” cells as a natural consequence of cell-to-cell communication and that this could tweak the signal transduction cascade to alter the protein synthesis landscape. We inserted
luxS
(AI-2 synthase) into vectors which cosynthesized proteins of interest (organophosphorus hydrolase [OPH], chloramphenicol acetyltransferase [CAT], or UV-variant green fluorescent protein [GFPuv]) and evaluated the protein expression in
luxS
-deficient hosts. In this way, we altered the level of
luxS
in the cells in order to “tune” the synthesis of AI-2. We found conditions in which the protein yield was dramatically increased. Further studies demonstrated coincident upregulation of the chaperone GroEL, which may have facilitated higher yields and is shown for the first time to be positively regulated at the posttranscriptional level by AI-2. This report is the first to demonstrate that the protein synthesis capacity of
E. coli
can be altered by rewiring quorum sensing circuitry.
Epidemiological Association of Different
Campylobacter jejuni
Groups with Metabolism-Associated Genetic Markers
Authors: Zautner Andreas E. , Herrmann Sahra , Corso Jasmin , Tareen A. Malik , Alter Thomas , Groß Uwe 
Published: January 2011

ABSTRACT

In this study, multilocus sequence typing (MLST) was combined with the genetic detection of six genetic markers,
ansB
,
dmsA
,
ggt
,
cj1585c
,
cjj81176
-
1367/71
(
cj1365c
), and the two-gene marker
tlp7
(
cj0951c
plus
cj0952c
), to assess if their presence correlated with different
C. jejuni
clonal groups. Using a collection of 266
C. jejuni
isolates from (in decreasing order of sample size) humans, chickens, cattle, and turkeys, it was further investigated whether the resulting genotypes correlated with the isolation source. We found combinations of the six marker genes to be mutually exclusive, and their patterns of presence or absence correlated to some degree with animal source. Together with MLST results, the obtained genotypes could be segregated into six groups. An association was identified for
ansB
,
dmsA
, and
ggt
with the MLST-clonal complexes (MLST-CC) 22, 42, 45, and 283, which formed the most prominent group, in which chickens were the most prevalent animal source. Two other groups, characterized by the presence of
cj1585c
,
cjj81176
-
1367/71
, and the two-gene marker
tlp7
, associated with either MLST-CC 21 or 61, were overrepresented in isolates of bovine origin. Mutually exclusive marker gene combinations were observed for
ansB
,
dmsA
, and
ggt
, typically found in CC 45 and the related CC 22, 42, and 283, whereas the other three marker genes were found mostly in CC 21, 48, and 206. The presence of the two-gene marker
tlp7
, which is typical for MLST 21 and 53 as well as for MLST-CC 61, strongly correlates with a bovine host; this is interpreted as an example of host adaptation. In cases of
C. jejuni
outbreaks, these genetic markers could be helpful for more effective source tracking.
Ammonia-Oxidizing Bacteria in Biofilters Removing Trihalomethanes Are Related to
Nitrosomonas oligotropha
Authors: Wahman David G. , Kirisits Mary Jo , Katz Lynn E. , Speitel Gerald E. 
Published: January 2011

ABSTRACT

Ammonia-oxidizing bacteria (AOB) in nitrifying biofilters degrading four regulated trihalomethanes—trichloromethane, bromodichloromethane, dibromochloromethane, and tribromomethane—were related to
Nitrosomonas oligotropha. N. oligotropha
is associated with chloraminated drinking water systems, and its presence in the biofilters might indicate that trihalomethane tolerance is another reason that this bacterium is dominant in chloraminated systems.
Impact of Sorbic Acid on Germinant Receptor-Dependent and -Independent Germination Pathways in
Bacillus cereus
Authors: van Melis C. C. J. , Nierop Groot M. N. , Abee T. 
Published: January 2011

ABSTRACT

Amino acid- and inosine-induced germination of
Bacillus cereus
ATCC 14579 spores was reversibly inhibited in the presence of 3 mM undissociated sorbic acid. Exposure to high hydrostatic pressure, Ca-dipicolinic acid (DPA), and bryostatin, an activator of PrkC kinase, negated this inhibition, pointing to specific blockage of signal transduction in germinant receptor-mediated germination.
Deleterious Effect of the Q
o
Inhibitor Compound Resistance-Conferring Mutation G143A in the Intron-Containing Cytochrome
b
Gene and Mechanisms for Bypassing It
Authors: Vallières Cindy , Trouillard Martin , Dujardin Geneviève , Meunier Brigitte 
Published: January 2011

ABSTRACT

The mutation G143A in the inhibitor binding site of cytochrome
b
confers a high level of resistance to fungicides targeting the
bc
1
complex. The mutation, reported in many plant-pathogenic fungi, has not evolved in fungi that harbor an intron immediately after the codon for G143 in the cytochrome
b
gene, intron bi2. Using
Saccharomyces
cerevisiae
as a model organism, we show here that a codon change from GGT to GCT, which replaces glycine 143 with alanine, hinders the splicing of bi2 by altering the exon/intron structure needed for efficient intron excision. This lowers the levels of cytochrome
b
and respiratory growth. We then investigated possible bypass mechanisms that would restore the respiratory fitness of a resistant mutant. Secondary mutations in the mitochondrial genome were found, including a point mutation in bi2 restoring the correct exon/intron structure and the deletion of intron bi2. We also found that overexpression of nuclear genes
MRS2
and
MRS3
, encoding mitochondrial metal ion carriers, partially restores the respiratory growth of the G143A mutant. Interestingly, the
MRS3
gene from the plant-pathogenic fungus
Botrytis
cinerea
, overexpressed in an
S
.
cerevisiae
G143A mutant, had a similar compensatory effect. These bypass mechanisms identified in yeast could potentially arise in pathogenic fungi.
Variable Infection Frequency and High Diversity of Multiple Strains of
Wolbachia pipientis
in
Perkinsiella
Planthoppers
Authors: Hughes G. L. , Allsopp P. G. , Brumbley S. M. , Woolfit M. , McGraw E. A. , O'Neill S. L. 
Published: January 2011

ABSTRACT

This survey of
Wolbachia
infections in populations of the planthoppers
Perkinsiella saccharicida
and
Perkinsiella vitiensis
revealed variable frequencies, low-titer infections, and high phylogenetic diversities of strains. These observations add to the growing realization that
Wolbachia
infections may be extremely common within invertebrates and yet occur infrequently within populations and at low titer within individuals.
eIF2α Kinases Control Chalone Production in Dictyostelium discoideum
Authors: Bowman Robert L. , Xiong Yanhua , Kirsten Janet H. , Singleton Charles K. 
Published: January 2011

ABSTRACT

Growing
Dictyostelium
cells secrete CfaD and AprA, two proteins that have been characterized as chalones. They exist within a high-molecular-weight complex that reversibly inhibits cell proliferation, but not growth, via cell surface receptors and a signaling pathway that includes G proteins. How the production of these two proteins is regulated is unknown.
Dictyostelium
cells possess three GCN2-type eukaryotic initiation factor 2 α subunit (eIF2α) kinases, proteins that phosphorylate the translational initiation factor eIF2α and possess a tRNA binding domain involved in their regulation. The
Dictyostelium
kinases have been shown to function during development in regulating several processes. We show here that expression of an unregulated, activated kinase domain greatly inhibits cell proliferation. The inhibitory effect on proliferation is not due to a general inhibition of translation. Instead, it is due to enhanced production of a secreted factor(s). Indeed, extracellular CfaD and AprA proteins, but not their mRNAs, are overproduced in cells expressing the activated kinase domain. The inhibition of proliferation is not seen when the activated kinase domain is expressed in cells lacking CfaD or AprA or in cells that contain a nonphosphorylatable eIF2α. We conclude that production of the chalones CfaD and AprA is translationally regulated by eIF2α phosphorylation. Both proteins are upregulated at the culmination of development, and this enhanced production is lacking in a strain that possesses a nonphosphorylatable eIF2α.
Role of the Npr1 Kinase in Ammonium Transport and Signaling by the Ammonium Permease Mep2 in Candida albicans
Authors: Neuhäuser Benjamin , Dunkel Nico , Satheesh Somisetty V. , Morschhäuser Joachim 
Published: January 2011

ABSTRACT

The ammonium permease Mep2 induces a switch from unicellular yeast to filamentous growth in response to nitrogen limitation in
Saccharomyces cerevisiae
and
Candida albicans
. In
S. cerevisiae
, the function of Mep2 and other ammonium permeases depends on the protein kinase Npr1. Mutants lacking
NPR1
cannot grow on low concentrations of ammonium and do not filament under limiting nitrogen conditions. A G349C mutation in Mep2 renders the protein independent of Npr1 and results in increased ammonium transport and hyperfilamentous growth, suggesting that the signaling activity of Mep2 directly correlates with its ammonium transport activity. In this study, we investigated the role of Npr1 in ammonium transport and Mep2-mediated filamentation in
C. albicans
. We found that the two ammonium permeases Mep1 and Mep2 of
C. albicans
differ in their dependency on Npr1. While Mep1 could function well in the absence of the Npr1 kinase, ammonium transport by Mep2 was virtually abolished in
npr1
Δ mutants. However, the dependence of Mep2 activity on Npr1 was relieved at higher temperatures (37°C), and Mep2 could efficiently induce filamentous growth under limiting nitrogen conditions in
npr1
Δ mutants. Like in
S. cerevisiae
, mutation of the conserved glycine at position 343 in Mep2 of
C. albicans
to cysteine resulted in Npr1-independent ammonium uptake. In striking contrast, however, the mutation abolished the ability of Mep2 to induce filamentous growth both in the wild type and in
npr1
Δ mutants. Therefore, a mutation that improves ammonium transport by Mep2 under nonpermissible conditions eliminates its signaling activity in
C. albicans
.
Regulatable Ras Activity Is Critical for Proper Establishment and Maintenance of Polarity in Aspergillus fumigatus
Authors: Fortwendel Jarrod R. , Juvvadi Praveen R. , Rogg Luise E. , Steinbach William J. 
Published: January 2011

ABSTRACT
Here we show that expression of a constitutively activated RasA allele, as the sole source of Ras activity, revealed novel Ras-induced phenotypes, including excessive vacuolar expansion and spontaneous lysis of hyphal compartments. These findings highlight the requirement for balanced Ras activity in the establishment and maintenance of polarized growth in filamentous fungi.
Complete Genome Sequence of the Veterinary Pathogen
Staphylococcus pseudintermedius
Strain HKU10-03, Isolated in a Case of Canine Pyoderma
Authors: Tse Herman , Tsoi Hoi Wah , Leung Sze Pui , Urquhart Ian James , Lau Susanna K. P. , Woo Patrick C. Y. , Yuen Kwok Yung 
Published: January 2011

ABSTRACT

Staphylococcus pseudintermedius
is a member of the coagulase-positive staphylococci and is the commonest cause of canine pyoderma. We report the first genome sequence of
S. pseudintermedius
, which shows the presence of numerous virulence factors akin to those of the related human pathogen
Staphylococcus aureus
.