bluuebunny/crossref_metadata_2025_split huggingface dataset:
Can
Anopheles gambiae
Be Infected with
Wolbachia pipientis
? Insights from an In Vitro System
Authors: Rasgon Jason L. , Ren Xiaoxia , Petridis Michael 
Published: December 2006

ABSTRACT

Wolbachia pipientis
are maternally inherited endosymbionts associated with cytoplasmic incompatibility, a potential mechanism to drive transgenic traits into
Anopheles
populations for malaria control.
W. pipientis
infections are common in many mosquito genera but have never been observed in any
Anopheles
species, leading to the hypothesis that
Anopheles
mosquitoes are incapable of harboring infection. We used an in vitro system to evaluate the ability of
Anopheles gambiae
cells to harbor diverse
W. pipientis
infections. We successfully established
W. pipientis
infections (strains
w
Ri and
w
AlbB) in the immunocompetent
Anopheles gambiae
cell line Sua5B. Infection was confirmed by PCR, antibiotic curing, DNA sequencing, and direct observation using fluorescence in situ hybridization. The infections were maintained at high passage rates for >30 passages. Our results indicate that there is no intrinsic genetic block to
W. pipientis
infection in
A. gambiae
cells, suggesting that establishment of in vivo
W. pipientis
infections in
Anopheles
mosquitoes may be feasible.
Mercury Methylation by Dissimilatory Iron-Reducing Bacteria
Authors: Kerin E. J. , Gilmour C. C. , Roden E. , Suzuki M. T. , Coates J. D. , Mason R. P. 
Published: December 2006

ABSTRACT

The Hg-methylating ability of dissimilatory iron-reducing bacteria in the genera
Geobacter
,
Desulfuromonas
, and
Shewanella
was examined. All of the
Geobacter
and
Desulfuromonas
strains tested methylated mercury while reducing Fe(III), nitrate, or fumarate. In contrast, none of the
Shewanella
strains produced methylmercury at higher levels than abiotic controls under similar culture conditions.
Geobacter
and
Desulfuromonas
are closely related to known Hg-methylating sulfate-reducing bacteria within the
Deltaproteobacteria.
Mixed Pollutant Degradation by
Methylosinus trichosporium
OB3b Expressing either Soluble or Particulate Methane Monooxygenase: Can the Tortoise Beat the Hare?
Authors: Lee Sung-Woo , Keeney David R. , Lim Dong-Hee , Dispirito Alan A. , Semrau Jeremy D. 
Published: December 2006

ABSTRACT

Methanotrophs have been widely investigated for in situ bioremediation due to their ubiquity and their ability to degrade halogenated hydrocarbons through the activity of methane monooxygenase (MMO). It has been speculated that cells expressing the soluble form of MMO (sMMO) are more efficient in cleaning up sites polluted with halogenated hydrocarbons due to its broader substrate range and relatively fast degradation rates compared cells expressing the other form of MMO, the particulate MMO (pMMO). To examine this issue, the biodegradation of mixtures of chlorinated solvents, i.e., trichloroethylene (TCE),
trans
-dichloroethylene (
t
-DCE), and vinyl chloride (VC), by
Methylosinus trichosporium
OB3b in the presence of methane using either form of MMO was investigated over longer time frames than those commonly used, i.e., days instead of hours. Growth of
M. trichosporium
OB3b along with pollutant degradation were monitored and analyzed using a simple comparative model developed from the Ω model created for analysis of the competitive binding of oxygen and carbon dioxide by ribulose bisphosphate carboxylase. From these findings, it appears that at concentrations of VC,
t
-DCE, and TCE greater than 10 μM each, methanotrophs expressing pMMO have a competitive advantage over cells expressing sMMO due to higher growth rates. Despite such an apparent growth advantage, pMMO-expressing cells degraded less of these substrates at these concentrations than sMMO-expressing cells during active growth. If the concentrations were increased to 100 μM, however, not only did pMMO-expressing cells grow faster, they degraded more of these pollutants and did so in a shorter amount of time. These findings suggest that the relative rates of growth substrate and pollutant degradation are important factors in determining which form of MMO should be considered for pollutant degradation.
Population Dynamics of
Bifidobacterium
Species in Human Feces during Raffinose Administration Monitored by Fluorescence In Situ Hybridization-Flow Cytometry
Authors: Dinoto Achmad , Marques Tatiana M. , Sakamoto Kanta , Fukiya Satoru , Watanabe Jun , Ito Susumu , Yokota Atsushi 
Published: December 2006

ABSTRACT

The population dynamics of bifidobacteria in human feces during raffinose administration were investigated at the species level by using fluorescence in situ hybridization (FISH) coupled with flow cytometry (FCM) analysis. Although double-staining FISH-FCM using both fluorescein isothiocyanate (FITC) and indodicarbocyanine (Cy5) as labeling dyes for fecal samples has been reported, the analysis was interfered with by strong autofluorescence at the FITC fluorescence region because of the presence of autofluorescence particles/debris in the fecal samples. We circumvented this problem by using only Cy5 fluorescent dye in the FISH-FCM analysis. Thirteen subjects received 2 g of raffinose twice a day for 4 weeks. Fecal samples were collected, and the bifidobacterial populations were monitored using the established FISH-FCM method. The results showed an increase in bifidobacteria from about 12.5% of total bacteria in the prefeeding period to about 28.7 and 37.2% after the 2-week and 4-week feeding periods, respectively.
Bifidobacterium adolescentis
, the
Bifidobacterium catenulatum
group, and
Bifidobacterium longum
were the major species, in that order, at the prefeeding period, and these bacteria were found to increase nearly in parallel during the raffinose administration. During the feeding periods, indigenous bifidobacterial populations became more diverse, such that minor species in human adults, such as
Bifidobacterium breve
,
Bifidobacterium bifidum
,
Bifidobacterium dentium
, and
Bifidobacterium angulatum
, proliferated. Four weeks after raffinose administration was stopped, the proportion of each major bifidobacterial species, as well as that of total bifidobacteria, returned to approximately the original values for the prefeeding period, whereas that of each minor species appeared to differ considerably from its original value. To the best of our knowledge, these results provide the first clear demonstration of the population dynamics of indigenous bifidobacteria at the species level in response to raffinose administration.
Sec-Mediated Transport of Posttranslationally Dehydrated Peptides in
Lactococcus lactis
Authors: Kuipers Anneke , Wierenga Jenny , Rink Rick , Kluskens Leon D. , Driessen Arnold J. M. , Kuipers Oscar P. , Moll Gert N. 
Published: December 2006

ABSTRACT

Nisin is a lanthionine-containing antimicrobial peptide produced by
Lactococcus lactis
. Its (methyl)lanthionines are introduced by two posttranslational enzymatic steps involving the dehydratase NisB, which dehydrates serine and threonine residues, and the cyclase NisC, which couples these dehydrated residues to cysteines, yielding thioether-bridged amino acids called lanthionines. The prenisin is subsequently exported by the ABC transporter NisT and extracellularly processed by the peptidase NisP.
L. lactis
expressing the
nisBTC
genes can modify and secrete a wide range of nonlantibiotic peptides. Here we demonstrate that in the absence of NisT and NisC, the Sec pathway of
L. lactis
can be exploited for the secretion of dehydrated variants of therapeutic peptides. Furthermore, posttranslational modifications by NisB and NisC still occur even when the nisin leader is preceded by a Sec signal peptide or a Tat signal peptide 27 or 44 amino acids long, respectively. However, transport of fully modified prenisin via the Sec pathway is impaired. The extent of NisB-mediated dehydration could be improved by raising the intracellular concentration NisB or by modulating the export efficiency through altering the signal sequence. These data demonstrate that besides the traditional lantibiotic transporter NisT, the Sec pathway with an established broad substrate range can be utilized for the improved export of lantibiotic enzyme-modified (poly)peptides.
EhRho1, a RhoA-Like GTPase of
Entamoeba histolytica
, Is Modified by Clostridial Glucosylating Cytotoxins
Authors: Majumder Shubhra , Schmidt Gudula , Lohia Anuradha , Aktories Klaus 
Published: December 2006

ABSTRACT

Clostridial glucosylating cytotoxins inactivate mammalian Rho GTPases by mono-O glucosylation of a conserved threonine residue located in the switch 1 region of the target protein. Here we report that EhRho1, a RhoA-like GTPase from the protozoan parasite
Entamoeba histolytica
, is glucosylated by clostridial cytotoxins. Recombinant glutathione
S
-transferase-EhRho1 and EhRho1 from cell lysate of
Entamoeba histolytica
were glucosylated by
Clostridium difficile
toxin B and
Clostridium novyi
alpha-toxin. In contrast,
Clostridium difficile
toxin A, which shares the same mammalian protein substrates with toxin B, did not modify EhRho1. Change of threonine 52 of EhRho1 to alanine prevented glucosylation by toxin B from
Clostridium difficile
and by alpha-toxin from
Clostridium novyi
, which suggests that the equivalent threonine residues are glucosylated in mammalian and
Entamoeba
Rho GTPases. Lethal toxin from
Clostridium sordellii
did not glucosylate EhRho1 but labeled several other substrate proteins in lysates from
Entamoeba histolytica
in the presence of UDP-[
14
C]glucose.
Genetic Manipulation of
Prochlorococcus
Strain MIT9313: Green Fluorescent Protein Expression from an RSF1010 Plasmid and Tn
5
Transposition
Authors: Tolonen Andrew C. , Liszt Gregory B. , Hess Wolfgang R. 
Published: December 2006

ABSTRACT

Prochlorococcus
is the smallest oxygenic phototroph yet described. It numerically dominates the phytoplankton community in the mid-latitude oceanic gyres, where it has an important role in the global carbon cycle. The complete genomes of several
Prochlorococcus
strains have been sequenced, revealing that nearly half of the genes in each genome are of unknown function. Genetic methods, such as reporter gene assays and tagged mutagenesis, are critical to unveiling the functions of these genes. Here, we describe conditions for the transfer of plasmid DNA into
Prochlorococcus
strain MIT9313 by interspecific conjugation with
Escherichia coli
. Following conjugation,
E. coli
bacteria were removed from the
Prochlorococcus
cultures by infection with
E. coli
phage T7. We applied these methods to show that an RSF1010-derived plasmid will replicate in
Prochlorococcus
strain MIT9313. When this plasmid was modified to contain green fluorescent protein, we detected its expression in
Prochlorococcus
by Western blotting and cellular fluorescence. Further, we applied these conjugation methods to show that a mini-Tn
5
transposon will transpose in vivo in
Prochlorococcus
. These genetic advances provide a basis for future genetic studies with
Prochlorococcus
, a microbe of ecological importance in the world's oceans.
Immunogenicity of Eight Dormancy Regulon-Encoded Proteins of
Mycobacterium tuberculosis
in DNA-Vaccinated and Tuberculosis-Infected Mice
Authors: Roupie Virginie , Romano Marta , Zhang Lei , Korf Hannelie , Lin May Young , Franken Kees L. M. C. , Ottenhoff Tom H. M. , Klein Michèl R. , Huygen Kris 
Published: December 2006

ABSTRACT

Hypoxia and low concentrations of nitric oxide have been reported to upregulate in vitro gene expression of 48 proteins of the dormancy (DosR) regulon of
Mycobacterium tuberculosis
. These proteins are thought to be essential for the survival of bacteria during persistence in vivo and are targeted by the immune system during latent infection in humans. Here we have analyzed the immunogenicity of eight DosR regulon-encoded antigens by plasmid DNA vaccination of BALB/c and C57BL/6 mice, i.e., Rv1733c, Rv1738, Rv2029c (
pfkB
), Rv2031c/
hspX
(
acr
), Rv2032 (
acg
), Rv2626c, Rv2627c, and Rv2628. Strong humoral and/or cellular Th1-type (interleukin-2 and gamma interferon) immune responses could be induced against all but one (Rv1738) of these antigens. The strongest Th1 responses were measured following vaccination with DNA encoding Rv2031c and Rv2626c. Using synthetic 20-mer overlapping peptides, 11 immunodominant, predicted major histocompatibility complex class II-restricted epitopes and one K
d
-restricted T-cell epitope could be identified. BALB/c and (B6D2)F
1
mice persistently infected with
M. tuberculosis
developed immune responses against Rv1733c, Rv2031c, and Rv2626c. These findings have implications for proof-of-concept studies in mice mimicking tuberculosis (TB) latency models and their extrapolation to humans for potential new vaccination strategies against TB.
Oral Administration of a
Salmonella enterica
-Based Vaccine Expressing
Bacillus anthracis
Protective Antigen Confers Protection against Aerosolized
B. anthracis
Authors: Stokes Margaret G. M. , Titball Richard W. , Neeson Brendan N. , Galen James E. , Walker Nicola J. , Stagg Anthony J. , Jenner Dominic C. , Thwaite Joanne E. , Nataro James P. , Baillie Leslie W. J. , Atkins Helen S. 
Published: December 2006

ABSTRACT

Bacillus anthracis
is the causative agent of anthrax, a disease that affects wildlife, livestock, and humans. Protection against anthrax is primarily afforded by immunity to the
B. anthracis
protective antigen (PA), particularly PA domains 4 and 1. To further the development of an orally delivered human vaccine for mass vaccination against anthrax, we produced
Salmonella enterica
serovar Typhimurium expressing full-length PA, PA domains 1 and 4, or PA domain 4 using codon-optimized PA DNA fused to the
S. enterica
serovar Typhi ClyA and under the control of the
ompC
promoter. Oral immunization of A/J mice with
Salmonella
expressing full-length PA protected five of six mice against a challenge with 10
5
CFU of aerosolized
B. anthracis
STI spores, whereas
Salmonella
expressing PA domains 1 and 4 provided only 25% protection (two of eight mice), and
Salmonella
expressing PA domain 4 or a
Salmonella
-only control afforded no measurable protection. However, a purified recombinant fusion protein of domains 1 and 4 provided 100% protection, and purified recombinant 4 provided protection in three of eight immunized mice. Thus, we demonstrate for the first time the efficacy of an oral
S. enterica
-based vaccine against aerosolized
B. anthracis
spores.
Streptococcus pneumoniae
Pilus Subunits Protect Mice against Lethal Challenge
Authors: Gianfaldoni Claudia , Censini Stefano , Hilleringmann Markus , Moschioni Monica , Facciotti Claudia , Pansegrau Werner , Masignani Vega , Covacci Antonello , Rappuoli Rino , Barocchi Michèle Anne , Ruggiero Paolo 
Published: December 2006

ABSTRACT

Streptococcus pneumoniae
is a major public health threat worldwide. The recent discovery that this pathogen possesses pili led us to investigate their protective abilities in a mouse model of intraperitoneal infection. Both active and passive immunization with recombinant pilus subunits afforded protection against lethal challenge with the
S. pneumoniae
serotype 4 strain TIGR4.
Modification of the Structure of Peptidoglycan Is a Strategy To Avoid Detection by Nucleotide-Binding Oligomerization Domain Protein 1
Authors: Wolfert Margreet A. , Roychowdhury Abhijit , Boons Geert-Jan 
Published: December 2006

ABSTRACTNucleotide-binding oligomerization domain (NOD) protein 1 (NOD1) and NOD2 are pathogen recognition receptors that sense breakdown products of peptidoglycan (PGN) (muropeptides). It is shown that a number of these muropeptides can induce tumor necrosis factor alpha (TNF-α) gene expression without significant TNF-α translation. This translation block is lifted when the muropeptides are coincubated with lipopolysaccharide (LPS), thereby accounting for an apparently synergistic effect of the muropeptides with LPS on TNF-α protein production. The compounds that induced synergistic effects were also able to activate NF-κB in a NOD1- or NOD2-dependent manner, implicating these proteins in synergistic TNF-α secretion. It was found that a diaminopimelic acid (DAP)-containing muramyl tetrapeptide could activate NF-κB in a NOD1-dependent manner, demonstrating that an exposed DAP is not essential for NOD1 sensing. The activity was lost when the α-carboxylic acid of iso-glutamic acid was modified as an amide. However, agonists of NOD2, such as muramyl dipeptide and lysine-containing muramyl tripeptides, were not affected by amidation of the α-carboxylic acid of iso-glutamic acid. Many pathogens modify the α-carboxylic acid of iso-glutamic acid of PGN, and thus it appears this is a strategy to avoid recognition by the host innate immune system. This type of immune evasion is in particular relevant for NOD1.
Difference in the Cytotoxic Effects of Toxin B fromClostridium difficileStrain VPI 10463 and Toxin B from VariantClostridium difficileStrain 1470
Authors: Huelsenbeck Johannes , Dreger Stefanie , Gerhard Ralf , Barth Holger , Just Ingo , Genth Harald 
Published: December 2006

ABSTRACTGlucosylation of RhoA, Rac1, and Cdc42 byClostridium difficiletoxin B from strain VPI 10463 (TcdB) results in actin reorganization (cytopathic effect) and apoptosis (cytotoxic effect). Toxin B from variantC. difficilestrain 1470 serotype F (TcdBF) differs from TcdB with regard to substrate proteins, as it glucosylates Rac1 and R-Ras but not RhoA and Cdc42. In this study, we addressed the question of whether the cellular effects of the toxins depend on their protein substrate specificity. Rat basophilic leukemia (RBL) cells were synchronized using the thymidine double-block technique. We show that cells were most sensitive to the cytotoxic effect of TcdB in S phase, as analyzed in terms of phosphatidyl serine externalization, fragmentation of nuclei, and activation of caspase-3; in contrast, TcdBF induced only a marginal cytotoxic effect, suggesting that inactivation of RhoA (but not of Rac1) was required for the cytotoxic effect. The glucosylation of Rac1 was correlated to the cytopathic effect of either toxin, suggesting a close connection of the two effects. The cytotoxic effect of TcdB was executed by caspase-3, as it was responsive to inhibition by acetyl-Asp-Met-Gln-Asp-aldehyde (Ac-DMQD-CHO), an inhibitor of caspase-3. The viability of TcdB-treated RBL cells was reduced, whereas the viability of TcdBF-treated cells was unchanged, further confirming that inactivation of RhoA is required for the cytotoxic effect. In conclusion, the protein substrate specificity of the glucosylating toxins determines their biological activity.
Global Gene Expression Profiling of Asymptomatic Bacteriuria
Escherichia coli
during Biofilm Growth in Human Urine
Authors: Hancock Viktoria , Klemm Per 
Published: December 2006

ABSTRACT

Urinary tract infection (UTI) is an important health problem worldwide, with many millions of cases each year, and
Escherichia coli
is the most common organism causing UTI in humans. Also,
E. coli
is responsible for most infections in patients with chronic indwelling bladder catheter. The two asymptomatic bacteriuria (ABU)
E. coli
strains 83972 and VR50 are significantly better biofilm formers in their natural growth medium, human urine, than the two uropathogenic
E. coli
isolates CFT073 and 536. We used DNA microarrays to monitor the expression profile during biofilm growth in urine of the two ABU strains 83972 and VR50. Significant differences in expression levels were seen between the biofilm expression profiles of the two strains with the corresponding planktonic expression profiles in morpholinepropanesulfonic acid minimal laboratory medium and human urine; 417 and 355 genes were up- and down-regulated, respectively, during biofilm growth in urine of 83972 and VR50. Many genes involved in transcription and stress were up-regulated in biofilm-grown cells. The role in biofilm formation of four of the up-regulated genes, i.e.,
yceP
,
yqgA
,
ygiD
, and
aaeX
, was investigated by creating single-knockout mutant versions of 83972 and VR50; all mutants showed reduced biofilm formation in urine by 18 to 43% compared with the wild type (
P
< 0.05). Also, the expression profile of strain 83972 in the human urinary tract partially overlaps with the biofilm expression profile.
Hip resurfacing: a technology reborn
Authors: Cutts Steven , Carter Paul B 
Published: December 2006

AbstractIn recent years there has been a resurgence of interest in the concept of hip resurfacing. Much of this interest has stemmed from the work of McMinn in the West Midlands. Hip resurfacing is now emerging as a viable alternative to conventional hip replacement. In this article, we discuss the conceptual advantages offered by hip resurfacing and review the early clinical results and the ongoing clinical concerns regarding this technology.
Chagas disease
Authors: Teixeira A R L , Nitz N , Guimaro M C , Gomes C , Santos-Buch C A 
Published: December 2006

Abstract
Chagas disease is the clinical condition triggered by infection with the protozoan Trypanosoma cruzi. The infection is transmitted by triatomine insects while blood feeding on a human host. Field studies predict that one third of an estimated 18 million T cruzi-infected humans in Latin America will die of Chagas disease. Acute infections are usually asymptomatic, but the ensuing chronic T cruzi infections have been associated with high ratios of morbidity and mortality: Chagas heart disease leads to unexpected death in 37.5% of patients, 58% develop heart failure and die and megacolon or megaoesophagus has been associated with death in 4.5%. The pathogenesis of Chagas disease appears to be related to a parasite-induced mutation of the vertebrate genome. Currently, treatment is unsatisfactory.
Evidence-based medicine: assessment of knowledge of basic epidemiological and research methods among medical doctors
Authors: Novack L , Jotkowitz A , Knyazer B , Novack V 
Published: December 2006

Abstract

Background
An understanding of statistical methods and basic epidemiology are crucial for the practice of modern medicine.

Aims
To assess (1) the knowledge of basic methods of conducting research and data analysis among residents and practicing doctors and (2) the effect of country of medical school graduation, professional status, medical article reading and writing experience on the level of this knowledge.

Methods
Data were collected by means of a supervised self-administered questionnaire, which was distributed among doctors at Soroka Medical Center, Beer-Sheva, Israel. The questionnaire included 10 multiple-choice questions on basic epidemiology and statistics, and respondent demographical data.

Results
Of the 260 eligible doctors, 219 (84.2%) returned completed questionnaires. Of the 219 doctors, 50% graduated more than 8.5 years ago, 39.7% were specialists and the remaining were residents. The most frequent specialty was internal medicine (37.4%). Israel was the most frequent country of graduation (45.7%), followed by the former Soviet Union (Eastern medical education; 38.4%). The median total score of knowledge was 4 of 10 questions (interquartile range 2–6). A higher score was associated with a Western medical education, being a specialist, shorter elapsed time since graduation, higher number of publications and self-reported reading of “methods” and “discussion” sections in scientific articles.

Conclusion
This study found a low level of knowledge of basic principles of research methods and data analysis among doctors, and this knowledge considerably differed by country of medical school graduation.