bluuebunny/crossref_metadata_2025_split huggingface dataset:
Genes Required for Plasmid R64 Thin-Pilus Biogenesis: Identification and Localization of Products of thepilK,pilM,pilO,pilP,pilR, andpilTGenes
Authors: Sakai Daisuke , Komano Teruya 
Published: July 2002

ABSTRACTWe have previously shown that thepilL,pilN,pilQ,pilS,pilU, andpilVgenes of plasmid R64 encode outer membrane lipoprotein, secretin, cytoplasmic ATPase, major pilin, prepilin peptidase, and minor pilin, respectively, which are required for thin-pilus formation. In this work, we characterized the products of the remaining essential genes,pilK,pilM,pilO,pilP,pilR, andpilT,with regard to their localization and processing. Overexpression systems containingpilM,pilO, andpilPgenes fused with N-terminal glutathioneS-transferase (GST) or a His tag were constructed. Overproduced proteins were purified and used to raise specific antibodies. Localization of PilM, PilO, and PilP proteins was performed by Western blot analysis with anti-GST-PilM, anti-PilO, and anti-PilP antibodies, respectively. ThepilK,pilR, andpilTproducts were produced with a C-terminal His tag and then detected by anti-His tag antibody. Subcellular fractionation experiments withEscherichia colicells producing R64 thin pili revealed that PilK, PilM, and PilR are inner membrane proteins, and PilP and PilT are periplasmic proteins. PilO protein was localized to the outer membrane in the presence of other Pil proteins, whereas it was localized to the cytoplasm in the absence of these proteins. Furthermore, the cleavage site of PilP protein was determined by N-terminal amino acid sequencing of purified mature PilP protein. We predict that PilK, PilM, PilO, PilP, and PilT proteins function as the components of the pilin transport apparatus and thin-pilus basal body.
The IntI-Like Tyrosine Recombinase ofShewanella oneidensisIs Active as an Integron Integrase
Authors: Drouin François , Mélançon Josiane , Roy Paul H. 
Published: July 2002

ABSTRACTWe have found an integron-like integrase gene and anattIsite inShewanella oneidensisas part of a small chromosomal integron. We have cloned this gene and tested the ability of the integrase to excise cassettes from various integrons. Most cassettes flanked by twoattCsites are readily excised, while cassettes in the “first” position, with anattI1orattI3site on one end, are not excised. An exception is a cassette withattI2on one end. TheattI2site, from Tn7, has greater similarity to theattIsite adjacent to the integrase ofS. oneidensisthan doattI1orattI3. We cloned theattIsite ofS. oneidensisand observed the integration of two different cassettes. We have, therefore, demonstrated the function of this integron-like integrase.
Bacillus subtilis
168 Contains Two Differentially Regulated Genes Encoding
l
-Asparaginase
Authors: Fisher Susan H. , Wray Lewis V. 
Published: July 2002

ABSTRACT

Expression of the two
Bacillus subtilis
genes encoding
l
-asparaginase is controlled by independent regulatory factors. The
ansZ
gene (formerly
yccC
) was shown by mutational analysis to encode a functional
l
-asparaginase, the expression of which is activated during nitrogen-limited growth by the TnrA transcription factor. Gel mobility shift and DNase I footprinting experiments indicate that TnrA regulates
ansZ
expression by binding to a DNA site located upstream of the
ansZ
promoter. The expression of the
ansA
gene, which encodes the second
l
-asparaginase, was found to be induced by asparagine. The
ansA
repressor, AnsR, was shown to negatively regulate its own expression.
A Conserved C-Terminal Region in Gp71 of the Small Isometric-Head Phage LL-H and ORF474 of the Prolate-Head Phage JCL1032 Is Implicated in Specificity of Adsorption of Phage to Its Host,
Lactobacillus delbrueckii
Authors: Ravin Victor , Räisänen Liisa , Alatossava Tapani 
Published: July 2002

ABSTRACT

Thirty-five phage-resistant mutants of
Lactobacillus delbrueckii
subsp.
lactis
ATCC 15808 were selected. Thirty-three of these mutants were assigned to the Bes group, while the remaining two were grouped under the Ads designation. Bes group mutants adsorbed phage LL-H but did not allow efficient phage development. Preliminary evidence suggests that these strains exhibit a mutation that changes the DNA specificity of a restriction-modification system. The Ads group mutants did not adsorb the small isometric-head phage LL-H. The results suggest that there are at least three different types of phage receptors in
L. delbrueckii
: two that are specific for small isometric-head phages and one that is specific for prolate-head phage JCL1032. Five LL-H host-range mutants which could overcome the adsorption block (a-type mutants) were selected and investigated by sequencing the genes
g71
and
g17
, which encode minor and major tail proteins, respectively. Each of the a-type mutants carried a nucleotide change at the 3′ end of gene
g71
. No mutations were observed in gene
g17
. Comparison of the gene product of
g71
of phage LL-H with its homolog in JCL1032 (ORF474) showed that these proteins had very similar C-terminal regions. No similarities were found at the N-terminal part of the proteins. We conclude that the C-terminal portion of the protein encoded by
g71
of phage LL-H and its homolog in phage JCL1032 determines the adsorption specificities of these phages on
L. delbrueckii
.
High Levels of Resistance to Metronidazole and Clarithromycin in
Helicobacter pylori
Strains in Children
Authors: Kalach Nicolas , Bergeret Michel , Benhamou Pierre Henri , Dupont Christophe , Raymond Josette 
Published: July 2002

ABSTRACT

The aim of the study was to evaluate the prevalence of resistance to amoxicillin, metronidazole, and clarithromycin before treatment of
Helicobacter pylori
infection in children and to assess the evolution of resistance with time. The study was carried out between 1994 and 1999 with 150
H. pylori
-positive children through gastric culture (antimicrobial susceptibility) and histology. All cultured
H. pylori
strains were sensitive to amoxicillin, 64 (43%) were resistant to metronidazole, 32 (21%) were resistant to clarithromycin, and 14 (9%) were resistant to both metronidazole and clarithromycin. The overall prevalence of resistance to metronidazole and clarithromycin did not change significantly with time. The study highlights the generalized high-level and stable metronidazole and clarithromycin resistance of
H. pylori
strains from children.
Cutaneous Infection Caused by
Aspergillus ustus
, an Emerging Opportunistic Fungus in Immunosuppressed Patients
Authors: Gené Josepa , Azón-Masoliver Antoni , Guarro Josep , De Febrer Gabriel , Martı́nez Angels , Grau Cristina , Ortoneda Montserrat , Ballester Frederic 
Published: July 2002

ABSTRACT

We report a case of primary cutaneous infection by the emerging fungus
Aspergillus ustus
in an immunosuppressed patient after a domestic accident. The patient failed to respond to itraconazole and died before receiving a new treatment with amphotericin B. There have been eight other cases reported since 1973, and only two patients survived the infection. In vitro susceptibility testing of seven antifungal drugs showed that terbinafine and the new azole derivative UR-9825 were the most active against this fungus.
Presence of
icaA
and
icaD
Genes and Slime Production in a Collection of Staphylococcal Strains from Catheter-Associated Infections
Authors: Arciola Carla Renata , Baldassarri Lucilla , Montanaro Lucio 
Published: July 2002

ABSTRACT

Both
Staphylococcus epidermidis
and
Staphylococcus aureus
are important causes of infections associated with catheters and other medical devices. It has recently been shown that not only
S. epidermidis
but also
S. aureus
can produce slime and carries the
ica
operon responsible for slime production. In the operon, coexpression of
icaA
and
icaD
is required for full slime synthesis. In this study, the presence of
icaA
and
icaD
was determined in a collection of 91 staphylococcal (68
S. epidermidis
and 23
S. aureus
) strains from intravenous catheter-associated infections, in 10 strains from the skin and mucosa of healthy volunteers, and in two reference strains by a PCR method. Slime-forming ability was tested on Congo red agar plates; 49% of
S. epidermidis
strains from catheters and, surprisingly, 61% of
S. aureus
strains were
icaA
and
icaD
positive and slime forming. All the saprophytic strains turned out to be negative for both
icaA
and
icaD
and also non-slime forming. Two
S. aureus
and one
S. epidermidis
strain from catheters, detected as
icaA
and
icaD
positive by PCR analysis and as slime forming (black colonies) at 24 h on Congo red agar, at 48 h exhibited tiny red spikes at the center of black colonies. The onset of these variants could not be ascribed to a mutagenic potential of Congo red, which, in the Ames test, was devoid of mutagenicity. PCR analysis showed that these red variants were negative for both
icaA
and
icaD
and even lacking the entire
icaADBC
operon. The data reported indicate an important role of
ica
genes as a virulence marker in staphylococcal infections from intravenous catheters.
Two Different Extended-Spectrum β-Lactamases (ESBLs) in One of the First ESBL-Producing Salmonella Isolates in Poland
Authors: Baraniak Anna , Sadowy Ewa , Hryniewicz Waleria , Gniadkowski Marek 
Published: July 2002

ABSTRACT

Two extended-spectrum β-lactamase (ESBL)-producing salmonella isolates,
Salmonella
enterica
serovar Enteritidis and
Salmonella
enterica
serovar Typhimurium, were analyzed. Both isolates produced the CTX-M-3 ESBL; however, their
bla
CTX-M-3
genes were located on different plasmids. The serovar Typhimurium isolate also expressed another ESBL, SHV-2a, and probably the two ESBL genes had been acquired independently by the strain.
Detection by Reverse Transcription-PCR and Genetic Characterization of Field Isolates of Swine Hepatitis E Virus from Pigs in Different Geographic Regions of the United States
Authors: Huang F. F. , Haqshenas G. , Guenette D. K. , Halbur P. G. , Schommer S. K. , Pierson F. W. , Toth T.E. , Meng X. J. 
Published: July 2002

ABSTRACT
Hepatitis E virus (HEV) is an important public health concern in many developing countries. HEV is also endemic in some industrialized counties, including the United States. With our recent discovery of swine HEV in pigs that is genetically closely related to human HEV, hepatitis E is now considered a zoonotic disease. Human strains of HEV are genetically heterogenic. So far in the United States, only one strain of swine HEV has been identified and characterized from a pig. To determine the extent of genetic variations and the nature of swine HEV infections in U.S. pigs, we developed a universal reverse transcription-PCR (RT-PCR) assay that is capable of detecting genetically divergent strains of HEV. By using this universal RT-PCR assay, we tested fecal and serum samples of pigs of 2 to 4 months of age from 37 different U.S. swine farms for the presence of swine HEV RNA. Thirty-four of the 96 pigs (35%) and 20 of the 37 swine herds (54%) tested were positive for swine HEV RNA. The sequences of a 348-bp region within the ORF2 gene of 27 swine HEV isolates from different geographic regions were determined. Sequence analyses revealed that the 27 U.S. swine HEV isolates shared 88 to 100% nucleotide sequence identities with each other and 89 to 98% identities with the prototype U.S. strain of swine HEV. These U.S. swine HEV isolates are only distantly related to the Taiwanese strains of swine HEV, with about 74 to 78% nucleotide sequence identities; to most known human strains of HEV worldwide, with <79% sequence identities; and to avian HEV, with 54 to 56% sequence identities. Phylogenetic analysis showed that all the U.S. swine HEV isolates identified in this study clustered in the same genotype with the prototype U.S. swine HEV and the two U.S. strains of human HEV. The data from this study indicated that swine HEV is widespread and enzoonotic in U.S. swine herds and that, as is with human HEV, swine HEV isolates from different geographic regions of the world are also genetically heterogenic. These data further raise potential concerns for zoonosis, xenozoonosis, and food safety.
Serratia ficaria
Endophthalmitis
Authors: Badenoch P. R. , Thom A. L. , Coster D. J. 
Published: July 2002

ABSTRACT

We report a case of
Serratia ficaria
endophthalmitis in a 73-year-old man. The patient's ocular history included a chemical burn, glaucoma, and corneal transplantation.
S. ficaria
is part of the fig tree ecosystem and is rarely isolated from clinical specimens. When it has been previously implicated as an agent of disease, the patients have been treated successfully and there have been no complications. In our patient, however, the infection resulted in the loss of the infected eye. This case illustrates that
S. ficaria
infection in a compromised patient can have serious consequences.
Vancomycin Susceptibility of Oxacillin-Resistant
Staphylococcus aureus
Isolates Causing Nosocomial Bloodstream Infections
Authors: Tallent Sandra M. , Bischoff Tammy , Climo Michael , Ostrowsky Belinda , Wenzel Richard P. , Edmond Michael B. 
Published: July 2002

ABSTRACT

Nosocomial oxacillin-resistant
Staphylococcus aureus
(ORSA) bloodstream isolates were tested to determine the prevalence of vancomycin heteroresistance. We screened 619 ORSA nosocomial bloodstream isolates from 36 hospitals between 1997 and 2000. Only one isolate exhibiting heterotypic resistance was detected. Thus, vancomycin heteroresistance in clinical bloodstream isolates remains rare in the United States.
The Role of CD8+T Cells and Major Histocompatibility Complex Class I Expression in the Central Nervous System of Mice Infected with Neurovirulent Sindbis Virus
Authors: Kimura Takashi , Griffin Diane E. 
Published: July 2002

ABSTRACTLittle is known about the role of CD8+T cells infiltrating the neural parenchyma during encephalitis induced by neurovirulent Sindbis virus (NSV). NSV preferentially infects neurons in the mouse brain and spinal cord; however, it is generally accepted that neurons can express few if any major histocompatibility complex (MHC) class I molecules. We evaluated the possible roles and interactions of CD8+T cells during NSV encephalitis and demonstrated that MHC class I antigen (H2K/D) was expressed on endothelial cells, inflammatory cells, and ependymal cells after intracerebral inoculation of NSV. No immunoreactivity was observed in neurons. On the other hand, in situ hybridization with probes for MHC class I heavy chain, β2 microglobulin, and TAP1 and TAP2 mRNAs revealed increased expression in a majority of neurons, as well as in inflammatory cells, endothelial cells, and ependymal cells in the central nervous system of infected mice. NSV-infected neurons may fail to express MHC class I molecules due to a posttranscriptional block or may express only nonclassical MHC class I genes. To better understand the role CD8+T cells play during fatal encephalitis induced by NSV, mice lacking functional CD8+T cells were studied. The presence or absence of CD8 did not alter outcome, but absence of β2 microglobulin improved survival. Interestingly, the intracellular levels of viral RNA decreased more rapidly in immunocompetent mice than in mice without functional CD8+T cells. These observations suggest that CD8+T cells may act indirectly, possibly via cytokines, to contribute to the clearance of viral RNA in neurons.
Characterization of the Influenza A Virus Gene Pool in Avian Species in Southern China: Was H6N1 a Derivative or a Precursor of H5N1?
Authors: Hoffmann Erich , Stech Juergen , Leneva Irina , Krauss Scott , Scholtissek Christoph , Chin Po San , Peiris Malik , Shortridge Kennedy F. , Webster Robert G. 
Published: July 2002

ABSTRACT
In 1997, an H5N1 influenza virus outbreak occurred in chickens in Hong Kong, and the virus was transmitted directly to humans. Because there is limited information about the avian influenza virus reservoir in that region, we genetically characterized virus strains isolated in Hong Kong during the 1997 outbreak. We sequenced the gene segments of a heterogeneous group of viruses of seven different serotypes (H3N8, H4N8, H6N1, H6N9, H11N1, H11N9, and H11N8) isolated from various bird species. The phylogenetic relationships divided these viruses into several subgroups. An H6N1 virus isolated from teal (A/teal/Hong Kong/W312/97 [H6N1]) showed very high (>98%) nucleotide homology to the human influenza virus A/Hong Kong/156/97 (H5N1) in the six internal genes. The N1 neuraminidase sequence showed 97% nucleotide homology to that of the human H5N1 virus, and the N1 protein of both viruses had the same 19-amino-acid deletion in the stalk region. The deduced hemagglutinin amino acid sequence of the H6N1 virus was most similar to that of A/shearwater/Australia/1/72 (H6N5). The H6N1 virus is the first known isolate with seven H5N1-like segments and may have been the donor of the neuraminidase and the internal genes of the H5N1 viruses. The high homology between the internal genes of H9N2, H6N1, and the H5N1 isolates indicates that these subtypes are able to exchange their internal genes and are therefore a potential source of new pathogenic influenza virus strains. Our analysis suggests that surveillance for influenza A viruses should be conducted for wild aquatic birds as well as for poultry, pigs, and humans and that H6 isolates should be further characterized.
Profilin Is Required for Optimal Actin-Dependent Transcription of Respiratory Syncytial Virus Genome RNA
Authors: Burke Emily , Mahoney Nicole M. , Almo Steven C. , Barik Sailen 
Published: July 2002

ABSTRACT

Transcription of human respiratory syncytial virus (RSV) genome RNA exhibited an obligatory need for the host cytoskeletal protein actin. Optimal transcription, however, required the participation of another cellular protein that was characterized as profilin by a number of criteria. The amino acid sequence of the protein, purified on the basis of its transcription-optimizing activity in vitro, exactly matched that of profilin. RSV transcription was inhibited 60 to 80% by antiprofilin antibody or poly-
l
-proline, molecules that specifically bind profilin. Native profilin, purified from extracts of lung epithelial cells by affinity binding to a poly-
l
-proline matrix, stimulated the actin-saturated RSV transcription by 2.5- to 3-fold. Recombinant profilin, expressed in bacteria, stimulated viral transcription as effectively as the native protein and was also inhibited by poly-
l
-proline. Profilin alone, in the absence of actin, did not activate viral transcription. It is estimated that at optimal levels of transcription, every molecule of viral genomic RNA associates with approximately the following number of protein molecules: 30 molecules of L, 120 molecules of phosphoprotein P, and 60 molecules each of actin and profilin. Together, these results demonstrated for the first time a cardinal role for profilin, an actin-modulatory protein, in the transcription of a paramyxovirus RNA genome.
Varicella-Zoster Virus Gene Expression in Latently Infected and Explanted Human Ganglia
Authors: Kennedy Peter G. E. , Grinfeld Esther , Bell Jeanne E. 
Published: July 2002

ABSTRACT
A consistent feature of varicella-zoster virus (VZV) latency is the restricted pattern of viral gene expression in human ganglionic tissues. To understand further the significance of this gene restriction, we used in situ hybridization (ISH) to detect the frequency of RNA expression for nine VZV genes in trigeminal ganglia (TG) from 35 human subjects, including 18 who were human immunodeficiency virus (HIV) positive. RNA for VZV gene 21 was detected in 7 of 11 normal and 6 of 10 HIV-positive subjects, RNA for gene 29 was detected in 5 of 14 normal and 11 of 11 HIV-positive subjects, RNA for gene 62 was detected in 4 of 10 normal and 6 of 9 HIV-positive subjects, and RNA for gene 63 was detected in 8 of 17 normal and 12 of 15 HIV-positive subjects. RNA for VZV gene 4 was detected in 2 of 13 normal and 4 of 9 HIV-positive subjects, and RNA for gene 18 was detected in 4 of 15 normal and 5 of 15 HIV-positive subjects. By contrast, RNAs for VZV genes 28, 40, and 61 were rarely or never detected. In addition, immunocytochemical analysis detected the presence of VZV gene 63-encoded protein in five normal and four HIV-positive subjects. VZV RNA was also analyzed in explanted fresh human TG and dorsal root ganglia from five normal human subjects over a period of up to 11 days in culture. We found a very different pattern of gene expression in these explants, with transcripts for VZV genes 18, 28, 29, 40, and 63 all frequently detected, presumably as a result of viral reactivation. Taken together, these data provide further support for the notion of significant and restricted viral gene expression in VZV latency.
The Human Immunodeficiency Virus Type 1 Tat Protein Up-Regulates the Promoter Activity of the Beta-Chemokine Monocyte Chemoattractant Protein 1 in the Human Astrocytoma Cell Line U-87 MG: Role of SP-1, AP-1, and NF-κB Consensus Sites
Authors: Lim Siew Pheng , Garzino-Demo Alfredo 
Published: July 2002

ABSTRACTIt has been shown that the human immunodeficiency virus type 1 (HIV-1) Tat protein can specifically enhance expression and release of monocyte chemoattractant protein 1 (MCP-1) from human astrocytes. In this study, we show evidence that Tat-induced MCP-1 expression is mediated at the transcriptional level. Transient transfection of an expression construct encoding the full-length Tat into the human glioblastoma-astrocytoma cell line U-87 MG enhances reporter gene activity from cotransfected deletion constructs of the MCP-1 promoter. HIV-1 Tat exerts its effect through a minimal construct containing 213 nucleotides upstream of the translational start site. Site-directed mutagenesis studies indicate that an SP1 site (located between nucleotides −123 and −115) is critical for both constitutive and Tat-enhanced expression of the human MCP-1 promoter, as mutation of this SP1 site significantly diminished reporter gene expression in both instances. Gel retardation experiments further demonstrate that Tat strongly enhances the binding of SP1 protein to its DNA element on the MCP-1 promoter. Moreover, we also observe an increase in the binding activities of transcriptional factors AP1 and NF-κB to the MCP-1 promoter following Tat treatment. Mutagenesis studies show that an upstream AP1 site and an adjacent NF-κB site (located at −128 to −122 and −150 to −137, respectively) play a role in Tat-mediated transactivation. In contrast, a further upstream AP1 site (−156 to −150) does not appear to be crucial for promoter activity. We postulate that a Tat-mediated increase in SP1 binding activities augments the binding of AP1 and NF-κB, leading to synergistic activation of the MCP-1 promoter.