bluuebunny/crossref_metadata_2025_split huggingface dataset:
Health Risk from the Use of Roof-Harvested Rainwater in Southeast Queensland, Australia, as Potable or Nonpotable Water, Determined Using Quantitative Microbial Risk Assessment
Authors: Ahmed W. , Vieritz A. , Goonetilleke A. , Gardner T. 
Published: September 2010

ABSTRACT

A total of 214 rainwater samples from 82 tanks were collected in urban Southeast Queensland (SEQ) in Australia and analyzed for the presence and numbers of zoonotic bacterial and protozoal pathogens using binary PCR and quantitative PCR (qPCR). Quantitative microbial risk assessment (QMRA) analysis was used to quantify the risk of infection associated with the exposure to potential pathogens from roof-harvested rainwater used as potable or nonpotable water. Of the 214 samples tested, 10.7%, 9.8%, 5.6%, and 0.4% were positive for the
Salmonella invA
,
Giardia lamblia
β-giardin,
Legionella pneumophila mip
, and
Campylobacter jejuni mapA
genes, respectively.
Cryptosporidium parvum
oocyst wall protein (COWP) could not be detected. The estimated numbers of
Salmonella
,
G. lamblia
, and
L. pneumophila
organisms ranged from 6.5 × 10
1
to 3.8 × 10
2
cells, 0.6 × 10° to 3.6 × 10° cysts, and 6.0 × 10
1
to 1.7 × 10
2
cells per 1,000 ml of water, respectively. Six risk scenarios were considered for exposure to
Salmonella
spp.,
G. lamblia
, and
L. pneumophila
. For
Salmonella
spp. and
G. lamblia
, these scenarios were (i) liquid ingestion due to drinking of rainwater on a daily basis, (ii) accidental liquid ingestion due to hosing twice a week, (iii) aerosol ingestion due to showering on a daily basis, and (iv) aerosol ingestion due to hosing twice a week. For
L. pneumophila
, these scenarios were (i) aerosol inhalation due to showering on a daily basis and (ii) aerosol inhalation due to hosing twice a week. The risk of infection from
Salmonella
spp.,
G. lamblia
, and
L. pneumophila
associated with the use of rainwater for showering and garden hosing was calculated to be well below the threshold value of one extra infection per 10,000 persons per year in urban SEQ. However, the risk of infection from ingesting
Salmonella
spp. and
G. lamblia
via drinking exceeded this threshold value and indicated that if undisinfected rainwater is ingested by drinking, then the incidences of the gastrointestinal diseases salmonellosis and giardiasis are expected to range from 9.8 × 10° to 5.4 × 10
1
(with a mean of 1.2 × 10
1
from Monte Carlo analysis) and from 1.0 × 10
1
to 6.5 × 10
1
cases (with a mean of 1.6 × 10
1
from Monte Carlo analysis) per 10,000 persons per year, respectively, in urban SEQ. Since this health risk seems higher than that expected from the reported incidences of gastroenteritis, the assumptions used to estimate these infection risks are critically examined. Nonetheless, it would seem prudent to disinfect rainwater for use as potable water.
The
Rhodococcus opacus
PD630 Heparin-Binding Hemagglutinin Homolog TadA Mediates Lipid Body Formation
Authors: MacEachran Daniel P. , Prophete M. E. , Sinskey A. J. 
Published: September 2010

ABSTRACT

Generally, prokaryotes store carbon as polyhydroxyalkanoate, starch, or glycogen. The Gram-positive actinomycete
Rhodococcus opacus
strain PD630 is noteworthy in that it stores carbon in the form of triacylglycerol (TAG). Several studies have demonstrated that
R. opacus
PD630 can accumulate up to 76% of its cell dry weight as TAG when grown under nitrogen-limiting conditions. While this process is well studied, the underlying molecular and biochemical mechanisms leading to TAG biosynthesis and subsequent storage are poorly understood. We designed a high-throughput genetic screening to identify genes and their products required for TAG biosynthesis and storage in
R. opacus
PD630. We identified a gene predicted to encode a putative heparin-binding hemagglutinin homolog, which we have termed
tadA
(
t
riacylglycerol
a
ccumulation
d
eficient), as being important for TAG accumulation. Kinetic studies of TAG accumulation in both the wild-type (WT) and mutant strains demonstrated that the
tadA
mutant accumulates 30 to 40% less TAG than the parental strain (WT). We observed that lipid bodies formed by the mutant strain were of a different size and shape than those of the WT. Characterization of TadA demonstrated that the protein is capable of binding heparin and of agglutinating purified lipid bodies. Finally, we observed that the TadA protein localizes to lipid bodies in
R. opacus
PD630 both
in vivo
and
in vitro
. Based on these data, we hypothesize that the TadA protein acts to aggregate small lipid bodies, found in cells during early stages of lipid storage, into larger lipid bodies and thus plays a key role in lipid body maturation in
R. opacus
PD630.
Cell Wall Anchoring of the 37-Kilodalton Oncofetal Antigen by
Lactobacillus plantarum
for Mucosal Cancer Vaccine Delivery
Authors: Fredriksen Lasse , Mathiesen Geir , Sioud Mouldy , Eijsink Vincent G. H. 
Published: September 2010

ABSTRACT

The 37-kDa oncofetal antigen (OFA), a tumor immunogen expressed on all mammalian cancers examined to date, was secreted and anchored to the cell wall of
Lactobacillus plantarum
using homologous signal peptides and LPxTG anchors. Orally administered
L. plantarum
expressing anchored OFA induced a specific immune response against OFA in mice.
Use of Cellular CRISPR (Clusters of Regularly Interspaced Short Palindromic Repeats) Spacer-Based Microarrays for Detection of Viruses in Environmental Samples
Authors: Snyder Jamie C. , Bateson Mary M. , Lavin Matthew , Young Mark J. 
Published: September 2010

ABSTRACT
It is currently difficult to detect unknown viruses in any given environment. The recent discovery of CRISPR (clusters of regularly interspaced short palindromic repeats) loci within bacterial and archaeal cellular genomes may provide an alternative approach to detect new viruses. It has been shown that the spacer sequences between the direct repeat units of the CRISPR loci are often derived from viruses and likely function as guide sequences to protect the cell from viral infection. The spacer sequences within the CRISPR loci may therefore serve as a record of the viruses that have replicated within the cell. We have cataloged the CRISPR spacer sequences from cellular metagenomic data from high-temperature (>80°C), acidic (pH < 4) hot spring environments located in Yellowstone National Park (YNP). We designed a microarray platform utilizing these CRISPR spacer sequences as potential probes to detect viruses present in YNP hot spring environments. We show that this microarray approach can detect viral sequences directly from virus-enriched environmental samples, detecting new viruses which have not been previously characterized. We further demonstrated that this microarray approach can be used to examine temporal changes in viral populations within the environment. Our results demonstrate that CRISPR spacer sequence-based microarrays will be useful tools for detecting and monitoring viruses from diverse environmental samples.
Salmonella entericain Commercial Swine Feed and Subsequent Isolation of Phenotypically and Genotypically Related Strains from Fecal Samples
Authors: Molla Bayleyegn , Sterman Allyson , Mathews Jennifer , Artuso-Ponte Valeria , Abley Melanie , Farmer William , Rajala-Schultz Päivi , Morrow W. E. Morgan , Gebreyes Wondwossen A. 
Published: September 2010

ABSTRACTThe purpose of this study was to determine the occurrence and genotypic relatedness ofSalmonella entericaisolates recovered from feed and fecal samples in commercial swine production units. Of 275 feed samples,Salmonellawas detected in 10 feed samples that originated from 8 of 36 (22.2%) barns, with a prevalence of 3.6% (10/275 samples). In fecal samples, a prevalence of 17.2% was found at the early finishing stage (1,180/6,880 samples), with a significant reduction in prevalence (7.4%) when pigs reached market age (392/5,321 samples). Of the 280Salmonellaisolates systematically selected for further characterization, 50% of the feed isolates and 55.3% of the isolates of fecal origin showed similar phenotypes based on antimicrobial resistance patterns and serogrouping. About 44% of the isolates were multidrug resistant. Pulsed-field gel electrophoresis (PFGE) genotyping grouped the 46 representative isolates into five genotypic clusters, of which four of the clusters consisted of genotypically related isolates recovered from feed and fecal samples. The occurrence of genotypically related and, in some cases, clonal strains, including multidrug-resistant isolates in commercially processed feed and fecal samples, suggests the high significance of commercial feed as a potential vehicle ofSalmonellatransmission.
Xyn10A, a Thermostable Endoxylanase from
Acidothermus cellulolyticus
11B
Authors: Barabote Ravi D. , Parales Juanito V. , Guo Ying-Yi , Labavitch John M. , Parales Rebecca E. , Berry Alison M. 
Published: September 2010

ABSTRACT

We cloned and purified the major family 10 xylanase (Xyn10A) from
Acidothermus cellulolyticus
11B. Xyn10A was active on oat spelt and birchwood xylans between 60°C and 100°C and between pH 4 and pH 8. The optimal activity was at 90°C and pH 6; specific activity and

K
m

for oat spelt xylan were 350 μmol xylose produced min
−1
mg of protein
−1
and 0.53 mg ml
−1
, respectively. Based on xylan cleavage patterns, Xyn10A is an endoxylanase, and its half-life at 90°C was approximately 1.5 h in the presence of xylan.
Evolutionary Relationships among Primary Endosymbionts of the Mealybug Subfamily Phenacoccinae (Hemiptera: Coccoidea: Pseudococcidae)
Authors: Gruwell Matthew E. , Hardy Nate B. , Gullan Penny J. , Dittmar Katharina 
Published: September 2010

ABSTRACT

Mealybugs (Coccoidea: Pseudococcidae) are sap-sucking plant parasites that harbor bacterial endosymbionts within specialized organs. Previous studies have identified two subfamilies, Pseudococcinae and Phenacoccinae, within mealybugs and determined the primary endosymbionts (P-endosymbionts) of the Pseudococcinae to be
Betaproteobacteria
(“
Candidatus
Tremblaya princeps”) containing
Gammaproteobacteria
secondary symbionts. Here, the P-endosymbionts of phenacoccine mealybugs are characterized based on 16S rRNA from the bacteria of 20 species of phenacoccine mealybugs and four outgroup
Puto
species (Coccoidea: Putoidae) and aligned to more than 100 published 16S rRNA sequences from symbiotic and free-living bacteria. Phylogenetic analyses recovered three separate lineages of bacteria from the Phenacoccinae, and these are considered to be the P-endosymbionts of their respective mealybug hosts, with those from (i) the mealybug genus
Rastrococcus
belonging to the
Bacteroidetes
, (ii) the subterranean mealybugs, tribe Rhizoecini, also within
Bacteroidetes
, in a clade sister to cockroach endosymbionts (
Blattabacterium
), and (iii) the remaining Phenacoccinae within the
Betaproteobacteria
, forming a well-supported sister group to “
Candidatus
Tremblaya princeps.” Names are proposed for two strongly supported lineages: “
Candidatus
Brownia rhizoecola” for P-endosymbionts of Rhizoecini and “
Candidatus
Tremblaya phenacola” for P-endosymbionts of Phenacoccinae excluding
Rastrococcus
and Rhizoecini. Rates of nucleotide substitution among lineages of
Tremblaya
were inferred to be significantly faster than those of free-living
Betaproteobacteria
. Analyses also recovered a clade of
Gammaproteobacteria
, sister to the P-endosymbiont lineage of aphids (“
Candidatus
Buchnera aphidicola”), containing the endosymbionts of Putoidae, the secondary endosymbionts of pseudococcine mealybugs, and the endosymbionts of several other insect groups.
lacZ
Reporter System for Use in
Borrelia burgdorferi
Authors: Hayes Beth M. , Jewett Mollie W. , Rosa Patricia A. 
Published: September 2010

ABSTRACT

Regulation of gene expression is critical for the ability of
Borrelia burgdorferi
to adapt to different environments during its natural infectious cycle. Reporter genes have been used successfully to study gene regulation in multiple organisms. We have introduced a
lacZ
gene into
B. burgdorferi
, and we show that
B. burgdorferi
produces a protein with detectable β-galactosidase activity in both liquid and solid media when
lacZ
is expressed from a constitutive promoter. Furthermore, when
lacZ
is expressed from the
ospC
promoter, β-galactosidase activity is detected only in
B. burgdorferi
clones that express
ospC
, and it accurately monitors endogenous gene expression. The addition of
lacZ
to the repertoire of genetic tools available for use in
B. burgdorferi
should contribute to a better understanding of how
B. burgdorferi
gene expression is regulated during the infectious cycle.
Isolation and Characterization of the Gene Cluster for Biosynthesis of the Thiopeptide Antibiotic TP-1161
Authors: Engelhardt Kerstin , Degnes Kristin F. , Zotchev Sergey B. 
Published: September 2010

ABSTRACT

Recently, we isolated a new thiopeptide antibiotic, TP-1161, from the fermentation broth of a marine actinomycete typed as a member of the genus
Nocardiopsis
. Here we report the identification, isolation, and analysis of the TP-1161 biosynthetic gene cluster from this species. The gene cluster was identified by mining a draft genome sequence using the predicted structural peptide sequence of TP-1161. Functional assignment of a ∼16-kb genomic region revealed 13 open reading frames proposed to constitute the TP-1161 biosynthetic locus. While the typical core set of thiopeptide modification enzymes contains one cyclodehydratase/dehydrogenase pair, paralogous genes predicted to encode additional cyclodehydratases and dehydrogenases were identified. Although attempts at heterologous expression of the TP-1161 gene cluster in
Streptomyces coelicolor
failed, its identity was confirmed through the targeted gene inactivation in the original host.
Genetic Transformation and Mutagenesis via Single-Stranded DNA in the Unicellular, Diazotrophic Cyanobacteria of the Genus
Cyanothece
Authors: Min Hongtao , Sherman Louis A. 
Published: September 2010

ABSTRACT

We describe a genetic system for producing specific gene knockouts in
Cyanothece
sp. strain PCC 7822 using a single-stranded DNA technique (B. Zorin, P. Hegemann, and I. Sizova, Eukaryot. Cell 4:1264-1272, 2005). The first fully segregated mutant was a Δ
nifK
mutant, and it was unable to grow on medium lacking combined nitrogen and produced virtually no hydrogen.
Covariation of Soil Bacterial Composition with Plant Rarity
Authors: Huguet Valérie , Rudgers Jennifer A. 
Published: September 2010

ABSTRACT
Rare and common plants are predicted to host different rhizospheric microbes. To evaluate this prediction, we used terminal restriction fragment length polymorphism (T-RFLP) analysis to compare rhizospheric bacteria from eight native grass species whose local abundances in their natural ecosystem spanned a 15-fold range. We observed that locally rare versus common plants are associated with divergent bacterial communities.
Novel Fluorescence-Assisted Whole-Cell Assay for Engineering and Characterization of Proteases and Their Substrates
Authors: Kostallas George , Samuelson Patrik 
Published: September 2010

ABSTRACTWe have developed a sensitive and highly efficient whole-cell methodology for quantitative analysis and screening of protease activityin vivo. The method is based on the ability of a genetically encoded protease to rescue a coexpressed short-lived fluorescent substrate reporter from cytoplasmic degradation and thereby confer increased whole-cell fluorescence in proportion to the protease's apparent activity in theEscherichia colicytoplasm. We demonstrated that this system can reveal differences in the efficiency with which tobacco etch virus (TEV) protease processes different substrate peptides. In addition, when analyzingE. colicells expressing TEV protease variants that differed in terms of theirin vivosolubility, cells containing the most-soluble protease variant exhibited the highest fluorescence intensity. Furthermore, flow cytometry screening allowed for enrichment and subsequent identification of an optimal substrate peptide and protease variant from a large excess of cells expressing suboptimal variants (1:100,000). Two rounds of cell sorting resulted in a 69,000-fold enrichment and a 22,000-fold enrichment of the superior substrate peptide and protease variant, respectively. Our approach presents a new promising path forward for high-throughput substrate profiling of proteases, engineering of novel protease variants with desired properties (e.g., altered substrate specificity and improved solubility and activity), and identification of protease inhibitors.
Moderate Temperature Fluctuations Rapidly Reduce the Viability of
Ralstonia solanacearum
Race 3, Biovar 2, in Infected Geranium, Tomato, and Potato Plants
Authors: Scherf Jacob M. , Milling Annett , Allen Caitilyn 
Published: September 2010

ABSTRACT

Most
Ralstonia solanacearum
strains are tropical plant pathogens, but race 3, biovar 2 (R3bv2), strains can cause bacterial wilt in temperate zones or tropical highlands where other strains cannot. R3bv2 is a quarantine pathogen in North America and Europe because of its potential to damage the potato industry in cooler climates. However, R3bv2 will not become established if it cannot survive temperate winters. Previous experiments showed that in water at 4°C, R3bv2 does not survive as long as native U.S. strains, but R3bv2 remains viable longer than U.S. strains in potato tubers at 4°C. To further investigate the effects of temperature on this high-concern pathogen, we assessed the ability of R3bv2 and a native U.S. strain to survive typical temperate winter temperature cycles of 2 days at 5°C followed by 2 days at −10°C. We measured pathogen survival in infected tomato and geranium plants, in infected potato tubers, and in sterile water. The population sizes of both strains declined rapidly under these conditions in all three plant hosts and in sterile water, and no culturable
R. solanacearum
cells were detected after five to seven temperature cycles in plant tissue. The fluctuations played a critical role in loss of bacterial viability, since at a constant temperature of −20°C, both strains could survive in infected geranium tissue for at least 6 months. These results suggest that even when sheltered in infected plant tissue, R3bv2 is unlikely to survive the temperature fluctuations typical of a northern temperate winter.
Novel Activity of
Rhodobacter sphaeroides
Spheroidene Monooxygenase CrtA Expressed in
Escherichia coli
Authors: Lee Pyung Cheon , Holtzapple Erik , Schmidt-Dannert Claudia 
Published: September 2010

ABSTRACT

The spheroidene monooxygenase CrtA of
Rhodobacter sphaeroides
introduces a keto group and/or hydroxy group at the ends of nonnative substrates in
Escherichia coli
, resulting in the production of novel oxocarotenoids. The heme-containing CrtA is not a P450 enzyme but a new type of oxygenase.
New Insights into the Fructosyltransferase Activity ofSchwanniomyces occidentalisβ-Fructofuranosidase, Emerging from Nonconventional Codon Usage and Directed Mutation
Authors: Álvaro-Benito Miguel , de Abreu Miguel , Portillo Francisco , Sanz-Aparicio Julia , Fernández-Lobato María 
Published: September 2010

ABSTRACTSchwanniomyces occidentalisβ-fructofuranosidase (Ffase) releases β-fructose from the nonreducing ends of β-fructans and synthesizes 6-kestose and 1-kestose, both considered prebiotic fructooligosaccharides. Analyzing the amino acid sequence of this protein revealed that it includes a serine instead of a leucine at position 196, caused by a nonuniversal decoding of the unique mRNA leucine codon CUG. Substitution of leucine for Ser196 dramatically lowers the apparent catalytic efficiency (kcat/Km) of the enzyme (approximately 1,000-fold), but surprisingly, its transferase activity is enhanced by almost 3-fold, as is the enzymes' specificity for 6-kestose synthesis. The influence of 6 Ffase residues on enzyme activity was analyzed on both the Leu196/Ser196 backgrounds (Trp47, Asn49, Asn52, Ser111, Lys181, and Pro232). Only N52S and P232V mutations improved the transferase activity of the wild-type enzyme (about 1.6-fold). Modeling the transfructosylation products into the active site, in combination with an analysis of the kinetics and transfructosylation reactions, defined a new region responsible for the transferase specificity of the enzyme.
Molecular Evidence for Multiple Infections as Revealed by Typing of
Asaia
Bacterial Symbionts of Four Mosquito Species
Authors: Chouaia Bessem , Rossi Paolo , Montagna Matteo , Ricci Irene , Crotti Elena , Damiani Claudia , Epis Sara , Faye Ingrid , Sagnon N'Fale , Alma Alberto , Favia Guido , Daffonchio Daniele , Bandi Claudio 
Published: September 2010

ABSTRACT

The recent increased detection of acetic acid bacteria (AAB) of the genus
Asaia
as symbionts of mosquitoes, such as
Anopheles
spp. and
Aedes
spp., prompted us to investigate the diversity of these symbionts and their relationships in different mosquito species and populations. Following cultivation-dependent and -independent techniques, we investigated the microbiota associated with four mosquito species,
Anopheles stephensi
,
Anopheles gambiae
,
Aedes aegypti
, and
Aedes albopictus
, which are important vectors of human and/or animal pathogens. Denaturing gradient gel electrophoresis (DGGE) analysis based on the 16S rRNA gene revealed the presence of several bacterial taxa, among which
Asaia
sequences were among the dominant in most of the samples. A collection of 281
Asaia
isolates in cell-free media was established from individuals belonging to the four species. The isolates were typed by internal transcribed spacer (ITS)-PCR, tRNA-PCR, BOX-PCR, and randomly amplified polymorphic DNA (RAPD)-PCR, revealing that different
Asaia
strains are present in different mosquito populations, and even in single individuals.
EseG, an Effector of the Type III Secretion System of
Edwardsiella tarda
, Triggers Microtubule Destabilization
Authors: Xie Hai Xia , Yu Hong Bing , Zheng Jun , Nie Pin , Foster Leonard J. , Mok Yu-Keung , Finlay B. Brett , Leung Ka Yin 
Published: September 2010

ABSTRACT

Edwardsiella tarda
is a Gram-negative enteric pathogen that causes hemorrhagic septicemia in fish and both gastrointestinal and extraintestinal infections in humans. A type III secretion system (T3SS) was recently shown to contribute to pathogenesis, since deletions of various T3SS genes increased the 50% lethal dose (LD
50
) by about 1 log unit in the blue gourami infection model. In this study, we report EseG as the first identified effector protein of T3SS. EseG shares partial homology with two
Salmonella
T3SS effectors (SseG and SseF) over a conserved domain (amino acid residues 142 to 192). The secretion of EseG is dependent on a functional T3SS and, in particular, requires the chaperone EscB. Experiments using TEM-1 β-lactamase as a fluorescence-based reporter showed that EseG was translocated into HeLa cells at 35°C. Fractionation of infected HeLa cells demonstrated that EseG was localized to the host membrane fraction after translocation. EseG is able to disassemble microtubule structures when overexpressed in mammalian cells. This phenotype may require a conserved motif of EseG (EseG
142-192
), since truncated versions of EseG devoid of this motif lose their ability to cause microtubule destabilization. By demonstrating the function of EseG, our study contributes to the understanding of
E. tarda
pathogenesis. Moreover, the approach established in this study to identify type III effectors can be used to identify and characterize more type III and possible type VI effectors in
Edwardsiella
.