bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cardioprotection of bradykinin at reperfusion involves transactivation of the epidermal growth factor receptor via matrix metalloproteinase‐8
Authors: Methner C. , Donat U. , Felix S. B. , Krieg T. 
Published: July 2009

AbstractAim:  The endogenous autacoid bradykinin (BK) reportedly reduces myocardial infarct size when given exogenously at reperfusion. Muscarinic and opioid G‐protein‐coupled receptors are equally protective and have been shown to couple through a matrix metalloproteinase (MMP)‐dependent transactivation of the epidermal growth factor receptor (EGFR). Here we test whether BK protects the rat heart through the EGFR by an MMP‐dependent pathway.Methods:  Infarct size was measured in isolated perfused rat hearts undergoing 30 min regional ischaemia followed by 120 min reperfusion. In additional studies HL‐1 cardiomyocytes were loaded with tetramethylrhodamine ethyl to measure their mitochondrial membrane potential (Ψm). Adding the calcium ionophore calcimycin, causes Ψm‐collapse presumably due to calcium‐induced mitochondrial permeability transition.Results:  As expected, BK (100 nmol L−1) started 5 min prior to reperfusion reduced infarct size from 38.9 ± 2.0% of the ischaemic zone in control hearts to 22.2 ± 3.3% (P < 0.001). Co‐infusing the EGFR inhibitor AG1478, the broad‐spectrum MMP‐inhibitor GM6001, or a highly selective MMP‐8 inhibitor abolished BK’s protection, thus suggesting an MMP‐8‐dependent EGFR transactivation in the signalling. Eighty minutes of exposure to calcimycin reduced the mean cell fluorescence to 37.4 ± 1.8% of untreated cells while BK could partly preserve the fluorescence and, hence, protect the cells (50.5 ± 2.3%, P < 0.001). The BK‐induced mitochondrial protection could again be blocked by AG1478, GM6001 and MMP‐8 inhibitor. Finally, Western blotting revealed that BK’s protection was correlated with increased phosphorylation of EGFR and its downstream target Akt.Conclusion:  These results indicate that BK at reperfusion triggers its protective signalling pathway through MMP‐8‐dependent transactivation of the EGFR.
Functions of glutamate transporters in cerebellar Purkinje cell synapses
Authors: Takayasu Y. , Iino M. , Takatsuru Y. , Tanaka K. , Ozawa S. 
Published: July 2009

AbstractGlutamate transporters play a critical role in the maintenance of low extracellular concentrations of glutamate, which prevents the overactivation of post‐synaptic glutamate receptors. Four distinct glutamate transporters, GLAST/EAAT1, GLT‐1/EAAT2, EAAC1/EAAT3 and EAAT4, are distributed in the molecular layer of the cerebellum, especially near glutamatergic synapses in Purkinje cells (PCs). This review summarizes the current knowledge about the differential roles of these transporters at excitatory synapses of PCs. Data come predominantly from electrophysiological experiments in mutant mice that are deficient in each of these transporter genes. GLAST expressed in Bergmann glia contributes to the clearing of the majority of glutamate that floods out of the synaptic cleft immediately after transmitter release from the climbing fibre (CF) and parallel fibre (PF) terminals. It is indispensable to maintain a one‐to‐one relationship in synaptic transmission at the CF synapses by preventing transcellular glutamate spillover. GLT‐1 plays a similar but minor role in the uptake of glutamate as GLAST. Although the loss of neither GLAST nor GLT‐1 affects cerebellar morphology, the deletion of both GLAST and GLT‐1 genes causes the death of the mutant animal and hinders the folium formation of the cerebellum. EAAT4 removes the low concentrations of glutamate that escape from uptake by glial transporters, preventing the transmitter from spilling over into neighbouring synapses. It also regulates the activation of metabotropic glutamate receptor 1 (mGluR1) in perisynaptic regions at PF synapses, which in turn affects mGluR1‐mediated events including slow EPSCs and long‐term depression. No change in synaptic function is detected in mice that are deficient in EAAC1.
Inhibition of Intracellular Growth of
Salmonella enterica
Serovar Typhimurium in Tissue Culture by Antisense Peptide-Phosphorodiamidate Morpholino Oligomer
Authors: Mitev Georgi M. , Mellbye Brett L. , Iversen Patrick L. , Geller Bruce L. 
Published: July 2009

ABSTRACT

Two types of phosphorodiamidate morpholino oligomers (PMOs) were tested for inhibition of growth of
Salmonella enterica
serovar Typhimurium. Both PMOs have the same 11-base sequence that is antisense to the region near the start codon of
acpP
, which is essential for lipid biosynthesis and viability. To the 3′ end of each is attached the membrane-penetrating peptide (RXR)
4
XB (R, X, and B indicate arginine, 6-aminohexanoic acid, and β-alanine, respectively). One peptide-PMO (AcpP PPMO) has no charge on the PMO moiety. The second PPMO has three cations (piperazine) attached to the phosphorodiamidate linkages (3+Pip-AcpP PPMO). A scrambled-sequence PPMO (Scr PPMO) was synthesized for each type of PMO. The MICs of AcpP PPMO, 3+Pip-AcpP PPMO, and either one of the Scr PPMOs were 1.25 μM (7 μg/ml), 0.156 μM (0.94 μg/ml), and >160 μM (>900 μg/ml), respectively. 3+Pip-AcpP PPMO at 1.25 or 2.5 μM significantly reduced the growth rates of pure cultures, whereas AcpP PPMO or either Scr PPMO had no effect. However, the viable cell count was significantly reduced at either concentration of 3+Pip-AcpP PPMO or AcpP PPMO, but not with either Scr PPMO. In other experiments, macrophages were infected intracellularly with
S. enterica
and treated with 3 μM 3+Pip-AcpP PPMO. Intracellular bacteria were reduced >99% with 3+Pip-AcpP PPMO, whereas intracellular bacteria increased 3 orders of magnitude in untreated or Scr PPMO-treated cultures. We conclude that either AcpP PPMO or 3+Pip-AcpP PPMO inhibited growth of
S. enterica
in pure culture and that 3+Pip-AcpP PPMO reduced intracellular viability of
S. enterica
in macrophages.
Contribution of
dfrA
and
inhA
Mutations to the Detection of Isoniazid-Resistant
Mycobacterium tuberculosis
Isolates
Authors: Ho Yu Min , Sun Yong-Jiang , Wong Sin-Yew , Lee Ann S. G. 
Published: July 2009

ABSTRACT

Screening of 127 isoniazid (INH)-resistant
Mycobacterium tuberculosis
isolates from Singapore for mutations within the
dfrA
and
inhA
genes revealed mutations in 0 and 5 (3.9%) isolates respectively, implying that mutations in
dfrA
do not contribute to the detection of INH-resistant
M. tuberculosis
and that mutations within
inhA
are rare. Thirty-seven (29%) of the 127 isolates had no mutations in any of the genes implicated in INH resistance (
katG
,
kasA
, and
ndh
;
inhA
and
ahpC
promoters), suggesting that there are new INH targets yet to be discovered.
Combination Chemotherapy against
Clonorchis sinensis
: Experiments with Artemether, Artesunate, OZ78, Praziquantel, and Tribendimidine in a Rat Model
Authors: Keiser Jennifer , Xiao Shu-Hua , Smith Thomas A. , Utzinger Jürg 
Published: July 2009

ABSTRACT

Caused by the Chinese liver fluke
Clonorchis sinensis
, clonorchiasis is of growing public health importance. Treatment and control of the disease rely on a single drug, praziquantel, and little information regarding combination chemotherapy is available. Here, we evaluated the in vivo efficacy of praziquantel combined with artemether, artesunate, OZ78, and tribendimidine, as well as an artesunate-tribendimidine combination against
C. sinensis
, in a rat model. Data from previous experiments were included, and negative binomial regression analyses were carried out to determine dose-response relationships and to study the effect of drug combination. All drugs given in monotherapy were efficacious in killing the worms; doses of 16 and 70 mg/kg of body weight of artesunate, for example, reduced worm burden by 50% and 95%, respectively. Artemether and OZ78 (12.5 to 50 mg/kg) showed dose-dependent killing of worms but no significant drug interactions when given with 150 mg/kg praziquantel, suggesting independent additive effects. In contrast, artesunate and tribendimidine (12.5 to 50 mg/kg) showed synergistic interactions with 150 mg/kg praziquantel. When low doses of 3.1 and 6.25 mg/kg OZ78 and artemether, respectively, were combined with praziquantel (150 mg/kg) an increased worm survival, above the level observed with praziquantel monotherapy, was noted. A similar antagonism was seen when praziquantel (75 mg/kg) was combined with several of the companion drugs at various doses. In conclusion, in vivo efficacy of praziquantel, the artemisinins, OZ78, and tribendimidine against
C. sinensis
is confirmed, and combination chemotherapy with praziquantel produces synergistic and antagonistic effects depending on the doses administered. Further preclinical investigations are warranted.
Intravenous Doripenem at 500 Milligrams versus Levofloxacin at 250 Milligrams, with an Option To Switch to Oral Therapy, for Treatment of Complicated Lower Urinary Tract Infection and Pyelonephritis
Authors: Naber K. G. , Llorens L. , Kaniga K. , Kotey P. , Hedrich D. , Redman R. 
Published: July 2009

ABSTRACT

The prospective, multicenter, double-blind study presented in this report evaluated whether or not intravenous (IV) administration of doripenem, a carbapenem with bactericidal activity against gram-negative and gram-positive uropathogens, is inferior to IV administration of levofloxacin in the treatment of complicated urinary tract infection (cUTI). Patients (
n
= 753) with complicated lower UTI or pyelonephritis were randomly assigned to receive IV doripenem at 500 mg every 8 h (q8h) or IV levofloxacin at 250 mg q24h. Patients in both treatment arms were eligible to switch to oral levofloxacin after 3 days of IV therapy to complete a 10-day treatment course if they demonstrated significant clinical and microbiological improvements. The microbiological cure rate (primary end point) was determined at the test-of-cure (TOC) visit occurring 5 to 11 days after the last dose of antibiotic. For the microbiologically evaluable patients (
n
= 545), the microbiological cure rates were 82.1% and 83.4% for doripenem and levofloxacin, respectively (95% confidence interval [CI] for the difference, −8.0 to 5.5%); in the microbiological modified intent-to-treat cohort (
n
= 648), the cure rates were 79.2% and 78.2%, respectively. Clinical cure rates at the TOC visit were 95.1% in the doripenem arm and 90.2% in the levofloxacin arm (95% CI around the difference in cure rates [doripenem cure rate minus levofloxacin cure rate], 0.2% to 9.6%). Both treatment regimens were generally well tolerated. Doripenem was found not to be inferior to levofloxacin in terms of therapeutics and is now approved for use in the United States and Europe for the treatment of adults with cUTI, including pyelonephritis. As fluoroquinolone resistance increases, doripenem may become a more important option for successful treatment of cUTIs, including treatment of pyelonephritis.
In Vitro Activities of Telavancin and Six Comparator Agents against Anaerobic Bacterial Isolates
Authors: Finegold Sydney M. , Bolanos Mauricio , Sumannen Paula H. , Molitoris Denise R. 
Published: July 2009

ABSTRACT

The antimicrobial activities of telavancin and six comparators were evaluated against 460 isolates of anaerobic bacteria. Telavancin demonstrated excellent activity against gram-positive anaerobes (MIC
90
, 2 μg/ml) and was the most potent agent tested against
Clostridium difficile
(MIC
90
, 0.25 μg/ml). As expected, gram-negative isolates were not inhibited by telavancin.
Impact of Therapeutic Treatment with β-Lactam on Transfer of the
bla
CTX-M-9
Resistance Gene from
Salmonella enterica
Serovar Virchow to
Escherichia coli
in Gnotobiotic Rats
Authors: Faure Stéphanie , Perrin-Guyomard Agnès , Delmas Jean-Michel , Laurentie Michel 
Published: July 2009

ABSTRACT

The conjugative transfer of the plasmid carrying the
bla
CTX-M-9
gene from
Salmonella enterica
serovar Virchow isolated from a chicken farm to a recipient
Escherichia coli
strain was evaluated in vitro and in axenic rats inoculated with both strains, with or without selective pressure due to therapeutic doses of cefixime. The transfer of the
bla
CTX-M-9
gene of
S. enterica
serovar Virchow to
E. coli
was confirmed in vitro, at a low frequency of 5.9 × 10
−8
transconjugants/donors. This transfer rate was higher in gnotobiotic rats and reached ∼10
−5
transconjugants/donors without selective pressure. This frequency was not affected by the addition of therapeutic doses of cefixime. Thus, estimates of in vitro transfer underestimated potential transfer in the digestive tract, and therapeutic doses of cefixime did not increase the selection for transconjugants.
Norovirus Distribution within an Estuarine Environment
Authors: Gentry Jennifer , Vinjé Jan , Guadagnoli Dominic , Lipp Erin K. 
Published: July 2009

ABSTRACT

Human norovirus (NoV) has been studied extensively as an important cause of gastroenteritis outbreaks worldwide. While oysters are a primary vehicle for infection, few studies have examined the wider distribution of NoV in the estuarine environment. Active shellfish-harvesting areas in Georgia were examined for the prevalence, genotype diversity, and concentrations of NoV in a variety of estuarine sample types over the course of 1 year. Of the 225 samples (9 oyster, 72 water, 72 63- to 200-μm plankton, and 72 >200-μm plankton) collected from 12 stations across two estuaries, 21 samples (9.3%) tested positive for NoV. By sample type, 55.0% (5/9) of oysters, 8.3% (6/72) of water samples, 11.1% (8/72) of 63- to 200-μm plankton samples, and 2.8% (2/72) of >200-μm plankton samples were positive for human NoV. The two NoV-positive >200-μm plankton samples, which contained mainly zooplankton, had the greatest quantity of NoV genomes (3.5 × 10
13
and 1.7 × 10
15
genomes g
−1
) of any sample tested. The majority, 90.5% (19/21), of the samples tested positive for genogroup I NoV, and only 9.5% (2/21) of the samples tested positive for genogroup II. The high concentrations of NoV in plankton samples compared to water and oyster samples were unexpected and provide new insights into the presence and distribution of human NoV in the water environment.
Establishment of
Agrobacterium tumefaciens
-Mediated Transformation of an Oleaginous Fungus,
Mortierella alpina
1S-4, and Its Application for Eicosapentaenoic Acid Producer Breeding
Authors: Ando Akinori , Sumida Yosuke , Negoro Hiroaki , Suroto Dian Anggraini , Ogawa Jun , Sakuradani Eiji , Shimizu Sakayu 
Published: July 2009

ABSTRACT

Gene manipulation tools for an arachidonic-producing filamentous fungus,
Mortierella alpina
1S-4, have not been sufficiently developed. In this study,
Agrobacterium tumefaciens
-mediated transformation (ATMT) was investigated for
M. alpina
1S-4 transformation, using the uracil-auxotrophic mutant (
ura5
−
strain) of
M. alpina
1S-4 as a host strain and the homologous
ura5
gene as a selectable marker gene. Furthermore, the gene for ω3-desaturase, catalyzing the conversion of n-6 fatty acid to n-3 fatty acid, was overexpressed in
M. alpina
1S-4 by employing the ATMT system. As a result, we revealed that the frequency of transformation surpassed 400 transformants/10
8
spores, most of the integrated T-DNA appeared as a single copy at a random position in chromosomal DNA, and most of the transformants (60 to 80%) showed mitotic stability. Moreover, the accumulation of n-3 fatty acid in transformants was observed under the conditions of optimal ω3-desaturase gene expression. In particular, eicosapentaenoic acid (20:5n-3), an end product of n-3 fatty acids synthesized in
M. alpina
1S-4, reached a maximum of 40% of total fatty acids. In conclusion, the ATMT system was found to be effective and suitable for the industrial strain
Mortierella alpina
1S-4 and will be a useful tool for basic mutagenesis research and for industrial breeding of this strain.
Characterization of Mundticin L, a Class IIa Anti-
Listeria
Bacteriocin from
Enterococcus mundtii
CUGF08
Authors: Feng Guoping , Guron Giselle K. P. , Churey John J. , Worobo Randy W. 
Published: July 2009

ABSTRACT

Enterococcus mundtii
CUGF08, a lactic acid bacterium isolated from alfalfa sprouts, was found to produce mundticin L, a new class IIa bacteriocin that has a high level of inhibitory activity against the genus
Listeria
. The plasmid-associated operons containing genes for the mundticin L precursor, the ATP binding cassette (ABC) transporter, and immunity were cloned and sequenced. The fifth residue of the conservative consensus sequence YGNGX in the mature bacteriocin is leucine instead of valine in the sequences of the homologous molecules mundticin KS (ATO6) and enterocin CRL35. The primary structures of the ABC transporter and the immunity protein are homologous but unique.
Tolerance of theRalstonia eutrophaClass I Polyhydroxyalkanoate Synthase for Translational Fusions to Its C Terminus Reveals a New Mode of Functional Display
Authors: Jahns Anika C. , Rehm Bernd H. A. 
Published: July 2009

ABSTRACTHere, the class I polyhydroxyalkanoate synthase (PhaC) fromRalstonia eutrophawas investigated regarding the functionality of its conserved C-terminal region and its ability to tolerate translational fusions to its C terminus. MalE, the maltose binding protein, and green fluorescent protein (GFP) were considered reporter proteins to be translationally fused to the C terminus. Interestingly, PhaC remained active only when a linker was inserted between PhaC and MalE, whereas MalE was not functional. However, the extension of the PhaC N terminus by 458 amino acid residues was required to achieve a functionality of MalE. These data suggested a positive interaction of the extended N terminus with the C terminus. To assess whether a linker and/or N-terminal extension is generally required for a functional C-terminal fusion, GFP was fused to the C terminus of PhaC. Both fusion partners were active without the requirement of a linker and/or N-terminal extension. A further reporter protein, the immunoglobulin G binding ZZ domain of protein A, was translationally fused to the N terminus of the fusion protein PhaC-GFP and resulted in a tripartite fusion protein mediating the production of polyester granules displaying two functional protein domains.
Cloning of a Novel Pyrethroid-Hydrolyzing Carboxylesterase Gene from
Sphingobium
sp. Strain JZ-1 and Characterization of the Gene Product
Authors: Wang Bao-zhan , Guo Peng , Hang Bao-jian , Li Lian , He Jian , Li Shun-peng 
Published: July 2009

ABSTRACT

A novel esterase gene,
pytH
, encoding a pyrethroid-hydrolyzing carboxylesterase was cloned from
Sphingobium
sp. strain JZ-1. The gene contained an open reading frame of 840 bp. Sequence identity searches revealed that the deduced enzyme shared the highest similarity with many α/β-hydrolase fold proteins (20 to 24% identities). PytH was expressed in
Escherichia coli
BL21 and purified using Ni-nitrilotriacetic acid affinity chromatography. It was a monomeric structure with a molecular mass of approximately 31 kDa and a pI of 4.85. PytH was able to transform
p
-nitrophenyl esters of short-chain fatty acids and a wide range of pyrethroid pesticides, and isomer selectivity was not observed. No cofactors were required for enzyme activity.
DYF-1 Is Required for Assembly of the Axoneme in
Tetrahymena thermophila
Authors: Dave Drashti , Wloga Dorota , Sharma Neeraj , Gaertig Jacek 
Published: July 2009

ABSTRACT

In most cilia, the axoneme can be subdivided into three segments: proximal (the transition zone), middle (with outer doublet microtubules), and distal (with singlet extensions of outer doublet microtubules). How the functionally distinct segments of the axoneme are assembled and maintained is not well understood. DYF-1 is a highly conserved ciliary protein containing tetratricopeptide repeats. In
Caenorhabditis elegans
, DYF-1 is specifically needed for assembly of the distal segment (G. Ou, O. E. Blacque, J. J. Snow, M. R. Leroux, and J. M. Scholey. Nature. 436:583-587, 2005). We show that
Tetrahymena
cells lacking an ortholog of DYF-1, Dyf1p, can assemble only extremely short axoneme remnants that have structural defects of diverse natures, including the absence of central pair and outer doublet microtubules and incomplete or absent B tubules on the outer microtubules. Thus, in
Tetrahymena
, DYF-1 is needed for either assembly or stability of the entire axoneme. Our observations support the conserved function for DYF-1 in axoneme assembly or stability but also show that the consequences of loss of DYF-1 for axoneme segments are organism specific.
Further Characterization of the
epa
Gene Cluster and Epa Polysaccharides of
Enterococcus faecalis
Authors: Teng Fang , Singh Kavindra V. , Bourgogne Agathe , Zeng Jing , Murray Barbara E. 
Published: July 2009

ABSTRACT

We previously identified a gene cluster,
epa
(for
e
nterocococcal
p
olysaccharide
a
ntigen), involved in polysaccharide biosynthesis of
Enterococcus faecalis
and showed that disruption of
epaB
and
epaE
resulted in attenuation in translocation, biofilm formation, resistance to polymorphonuclear leukocyte (PMN) killing, and virulence in a mouse peritonitis model. Using five additional mutant disruptions in the 26-kb region between
orfde2
and OG1RF_0163, we defined the
epa
locus as the area from
epaA
to
epaR
. Disruption of
epaA
,
epaM
, and
epaN
, like prior disruption of
epaB
and
epaE
, resulted in alteration in Epa polysaccharide content, more round cells versus oval cells with OG1RF, decreased biofilm formation, attenuation in a mouse peritonitis model, and resistance to lysis by the phage NPV-1 (known to lyse OG1RF), while mutants disrupted in
orfde2
and OG1RF_163 (the
epa
locus flanking genes) behaved like OG1RF in those assays. Analysis of the purified Epa polysaccharide from OG1RF revealed the presence of rhamnose, glucose, galactose, GalNAc, and GlcNAc in this polysaccharide, while carbohydrate preparation from the
epaB
mutant did not contain rhamnose, suggesting that one or more of the glycosyl transferases encoded by the
epaBCD
operon are necessary to transfer rhamnose to the polysaccharide. In conclusion, the
epa
genes, uniformly present in
E. faecalis
strains and involved in biosynthesis of polysaccharide in OG1RF, are also important for OG1RF shape determination, biofilm formation, and NPV-1 replication/lysis, as well as for
E. faecalis
virulence in a mouse peritonitis model.
A Transmembrane Domain-Containing Surface Protein fromToxoplasma gondiiAugments Replication in Activated Immune Cells and Establishment of a Chronic Infection
Authors: Pollard Angela M. , Skariah Sini , Mordue Dana G. , Knoll Laura J. 
Published: July 2009

ABSTRACTToxoplasma gondiimutants identified as defective in the establishment of chronic infection were screened to isolate those specifically impaired in their ability to replicate within activated macrophages. One of the identified mutants contains an insertion in the hypothetical gene TGME49_111670. Genetic complementation restores the ability of the mutant to replicate in immune cells and produce cysts in the brains of mice. While the mutant is more sensitive to nitric oxide than is its parental strain, it is not defective in its ability to suppress nitric oxide. The disrupted protein has no significant homology to proteins with known functions, but is predicted to have one transmembrane domain. Immunofluorescence shows the protein on the parasite surface, even in activated macrophages, colocalizing with a tachyzoite surface antigen, SAG1, and oriented with its C-terminal end external. Western analysis reveals that the protein is downregulated in bradyzoites. Despite the tachyzoite specificity of this protein, mice infected with the mutant succumb to acute infection similarly to those infected with the parent strain. Serum samples from mice with chronicT. gondiiinfection react to a polypeptide from TGME49_11670, indicating that the protein is seen by the immune system during infection. This study is the first to characterize aT. gondiisurface protein that contains a transmembrane domain and show that the protein contributes to parasite replication in activated immune cells and the establishment of chronic infection.