bluuebunny/crossref_metadata_2025_split huggingface dataset:
Targeting of
D
MinC/MinD and
D
MinC/DicB Complexes to Septal Rings in
Escherichia coli
Suggests a Multistep Mechanism for MinC-Mediated Destruction of Nascent FtsZ Rings
Authors: Johnson Jay E. , Lackner Laura L. , de Boer Piet A. J. 
Published: July 2002

ABSTRACT

The MinC protein is an important determinant of septal ring positioning in
Escherichia coli
. The N-terminal domain (
Z
MinC) suppresses septal ring formation by interfering with FtsZ polymerization, whereas the C-terminal domain (
D
MinC) is required for dimerization as well as for interaction with the MinD protein. MinD oscillates between the membrane of both cell halves in a MinE-dependent fashion. MinC oscillates along with MinD such that the time-integrated concentration of
Z
MinC at the membrane is minimal, and hence the stability of FtsZ polymers is maximal, at the cell center. MinC is cytoplasmic and fails to block FtsZ assembly in the absence of MinD, indicating that recruitment of MinC by MinD to the membrane enhances
Z
MinC function. Here, we present evidence that the binding of
D
MinC to MinD endows the MinC/MinD complex with a more specific affinity for a septal ring-associated target in vivo. Thus, MinD does not merely attract MinC to the membrane but also aids MinC in specifically binding to, or in close proximity to, the substrate of its
Z
MinC domain. MinC-mediated division inhibition can also be activated in a MinD-independent fashion by the DicB protein of cryptic prophage Kim. DicB shows little homology to MinD, and how it stimulates MinC function has been unclear. Similar to the results obtained with MinD, we find that DicB interacts directly with
D
MinC, that the
D
MinC/DicB complex has a high affinity for some septal ring target(s), and that MinC/DicB interferes with the assembly and/or integrity of FtsZ rings in vivo. The results suggest a multistep mechanism for the activation of MinC-mediated division inhibition by either MinD or DicB and further expand the number of properties that can be ascribed to the Min proteins.
Cloning and Analysis of the Telomere and Terminal Inverted Repeat of the Linear Chromosome of
Streptomyces griseus
Authors: Goshi Kohei , Uchida Tetsuya , Lezhava Alexander , Yamasaki Masayuki , Hiratsu Keiichiro , Shinkawa Hidenori , Kinashi Haruyasu 
Published: July 2002

ABSTRACT

Cloning and sequencing of the telomere of
Streptomyces griseus
revealed five palindromic sequences in the terminal 116 nucleotides, all of which can make a hairpin loop structure. However, the end sequence cannot form the foldback secondary structure that is common in
Streptomyces
telomeres and is suggested to be necessary for terminal replication. Both inside ends of the terminal inverted repeat (TIR) were also cloned and sequenced. The results confirmed the size of the TIR to be 24 kb and identified two almost identical open reading frames that might have been involved in the formation of the TIR.
Genetic Locus Encoding Functions Involved in Biosynthesis and Outer Membrane Localization of Xanthomonadin in
Xanthomonas oryzae
pv. oryzae
Authors: Goel Ajay Kumar , Rajagopal Lakshmi , Nagesh Narayana , Sonti Ramesh V. 
Published: July 2002

ABSTRACT

Xanthomonadins are membrane-bound, brominated, aryl-polyene pigments specific to the genus
Xanthomonas
. We have characterized a genetic locus (
pig
) from
Xanthomonas oryzae
pv. oryzae which contains four open reading frames (ORFs) that are essential for xanthomonadin production. Three of these ORFs are homologous to acyl carrier proteins, dehydratases, and acyl transferases, suggesting a type II polyketide synthase pathway for xanthomonadin biosynthesis. The fourth ORF has no homologue in the database. For the first time, we report that a putative cytoplasmic membrane protein encoded in the
pig
locus is required for outer membrane localization of xanthomonadin in
X. oryzae
pv. oryzae. We also report the identification of a novel 145-bp palindromic
Xanthomonas
repetitive intergenic consensus element that is present in two places in the
pig
locus. We estimate that more than 100 copies of this element might be present in the genome of
X. oryzae
pv. oryzae and other xanthomonads.
The
Rhizobium etli cyaC
Product: Characterization of a Novel Adenylate Cyclase Class
Authors: Téllez-Sosa Juan , Soberón Nora , Vega-Segura Alicia , Torres-Márquez María E. , Cevallos Miguel A. 
Published: July 2002

ABSTRACT

Adenylate cyclases (ACs) catalyze the formation of 3′,5′-cyclic AMP (cAMP) from ATP. A novel AC-encoding gene,
cyaC
, was isolated from
Rhizobium etli
by phenotypic complementation of an
Escherichia coli cya
mutant. The functionality of the
cyaC
gene was corroborated by its ability to restore cAMP accumulation in an
E. coli cya
mutant. Further, overexpression of a
malE
::
cyaC
fusion protein allowed the detection of significant AC activity levels in cell extracts of an
E. coli cya
mutant. CyaC is unrelated to any known AC or to any other protein exhibiting a currently known function. Thus, CyaC represents the first member of a novel class of ACs (class VI). Hypothetical genes of unknown function similar to
cyaC
have been identified in the genomes of the related bacterial species
Mesorhizobium loti
,
Sinorhizobium meliloti
, and
Agrobacterium tumefaciens
. The
cyaC
gene is cotranscribed with a gene similar to
ohr
of
Xanthomonas campestris
and is expressed only in the presence of organic hydroperoxides. The physiological performance of an
R. etli cyaC
mutant was indistinguishable from that of the wild-type parent strain both under free-living conditions and during symbiosis.
Two Opines Control Conjugal Transfer of anAgrobacteriumPlasmid by Regulating Expression of Separate Copies of the Quorum-Sensing Activator GenetraR
Authors: Oger Philippe , Farrand Stephen K. 
Published: July 2002

ABSTRACTConjugal transfer of Ti plasmids fromAgrobacteriumspp. is controlled by a hierarchical regulatory system designed to sense two environmental cues. One signal, a subset of the opines produced by crown gall tumors initiated on plants by the pathogen, serves to induce production of the second, an acyl-homoserine lactone quorum-sensing signal, the quormone, produced by the bacterium itself. This second signal activates TraR, and this transcriptional activator induces expression of thetraregulon. Opines control transfer because thetraRgene is a member of an operon the expression of which is regulated by the conjugal opine. Among the Ti plasmid systems studied to date, only one of the two or more opine families produced by the associated tumor induces transfer. However, two chemically dissimilar opines, nopaline and agrocinopines A and B, induce transfer of the opine catabolic plasmid pAtK84b found in the nonpathogenicAgrobacterium radiobacterisolate K84. In this study we showed that this plasmid contains two copies oftraR, and each is associated with a different opine-regulated operon. One copy,traRnoc, is the last gene of thenoxoperon and was induced by nopaline but not by agrocinopines A and B. MutatingtraRnocabolished induction of transfer by nopaline but not by the agrocinopines. A mutation inocd, an upstream gene of thenoxoperon, abolished utilization of nopaline and also induction of transfer by this opine. The second copy,traRacc, is located in an operon of four genes and was induced by agrocinopines A and B but not by nopaline. Genetic analysis indicated that this gene is required for induction of transfer by agrocinopines A and B but not by nopaline. pAtK84b with mutations in bothtraRgenes was not induced for transfer by either opine. However, expression of atraRgene intransto this plasmid resulted in opine-independent transfer. The association oftraRnocwithnoxis unique, but the operon containingtraRaccis related to thearcoperons of pTiC58 and pTiChry5, two Ti plasmids inducible for transfer by agrocinopines A-B and C-D, respectively. We conclude that pAtK84b codes for two independently functioning copies oftraR, each regulated by a different opine, thus accounting for the activation of the transfer system of this plasmid by the two opine types.
Rapid Detection of Methicillin Resistance in Coagulase-Negative Staphylococci by a Penicillin-Binding Protein 2a-Specific Latex Agglutination Test
Authors: Horstkotte Matthias A. , Knobloch Johannes K.-M. , Rohde Holger , Mack Dietrich 
Published: July 2002

ABSTRACT

The detection of PBP 2a by the MRSA-Screen latex agglutination test with 201 clinical coagulase-negative staphylococci had an initial sensitivity of 98% and a high degree of specificity for
Staphylococcus epidermidis
strains compared to PCR for
mecA
. Determination of oxacillin MICs evaluated according to the new breakpoint (0.5 μg/ml) of the National Committee for Clinical Laboratory Standards exhibited an extremely low specificity for this population.
Identification and Characterization of Phage Variants of a Strain of Epidemic Methicillin-Resistant
Staphylococcus aureus
(EMRSA-15)
Authors: O'Neill G. L. , Murchan S. , Gil-Setas A. , Aucken H. M. 
Published: July 2002

ABSTRACT

EMRSA-15 is one of the most important strains of epidemic methicillin-resistant
Staphylococcus aureus
(EMRSA) found in the United Kingdom. It was originally characterized by weak lysis with phage 75 and production of enterotoxin C but not urease. Two variant strains of EMRSA-15 which show a broader phage pattern than the progenitor strain have emerged. A total of 153 recent clinical isolates representing classical EMRSA-15 (55 isolates) or these phage variants (98 isolates) were compared by
Sma
I macrorestriction profiles in pulsed-field gel electrophoresis (PFGE) as well as by urease and enterotoxin C production. Eight of the 98 isolates were shown to be other unrelated strains by both PFGE and their production of urease, a misidentification rate of 8% by phage typing. Seventy-one EMRSA-15 isolates were enterotoxin C negative, and the majority of these were sensitive to phage 81. Examination of PFGE profiles and Southern blotting studies suggest that the enterotoxin C gene locus is encoded on a potentially mobile DNA segment of ca. 15 kb. After elimination of the eight non-EMRSA-15 isolates, the remaining 145 were characterized by PFGE, yielding 22 profiles. All profiles were within five band differences of at least one other profile. Classical EMRSA-15 isolates showed nine PFGE profiles, with the majority of isolates (68%) in profile B1. Six of these nine PFGE profiles were unique to the classical EMRSA-15 isolates. Among the phage variants of EMRSA-15, 16 profiles were seen, but the majority of isolates (83%) fell into 1 of 4 profiles (B2, B3, B4, and B7) which correlated well with phage patterns. The most divergent PFGE profiles among the EMRSA-15 isolates had as many as 12 band differences from one another, suggesting that in examining isolates belonging to such a temporally and geographically disseminated epidemic strain, the range of PFGE profiles must be regarded as a continuum and analyzed by relating the profiles back to the most common or progenitor profile.
Candida
Species Exhibit Differential In Vitro Hemolytic Activities
Authors: Luo Gang , Samaranayake Lakshman P. , Yau Joyce Y. Y. 
Published: July 2002

ABSTRACT

A total of 80
Candida
isolates representing 14 species were examined for their respective responses to an in vitro hemolytic test. A modification of a previously described plate assay system where the yeasts are incubated on glucose (3%)-enriched sheep blood agar in a carbon dioxide (5%)-rich environment for 48 h was used to evaluate the hemolytic activity. A group of eight
Candida
species which included
Candida albicans
(15 isolates),
C. dubliniensis
(2),
C. kefyr
(2),
C. krusei
(4),
C. zeylanoides
(1),
C. glabrata
(34),
C. tropicalis
(5), and
C. lusitaniae
(2) demonstrated both alpha and beta hemolysis at 48 h postinoculation. Only alpha hemolysis was detectable in four
Candida
species, viz.,
C. famata
(3),
C. guilliermondii
(4),
C. rugosa
(1), and
C. utilis
(1), while
C. parapsilosis
(5) and
C. pelliculosa
(1) failed to demonstrate any hemolytic activity after incubation for 48 h or longer. This is the first study to demonstrate the variable expression profiles of hemolysins by different
Candida
species.
Immunofluorescent Detection of Intraerythrocytic
Bartonella henselae
in Naturally Infected Cats
Authors: Rolain J. M. , La Scola B. , Liang Z. , Davoust B. , Raoult D. 
Published: July 2002

ABSTRACT

To determine the presence of
Bartonella henselae
bacteremia in six cats, we compared isolation using blood culture with direct immunofluorescence on blood smears. Three cats that were positive by blood culture were also positive by direct immunofluorescence, and laser confocal microscopy confirmed the intraerythrocytic location of
B. henselae
.
Quantitative Detection of
Streptococcus pneumoniae
in Nasopharyngeal Secretions by Real-Time PCR
Authors: Greiner Oliver , Day Philip J. R. , Bosshard Philipp P. , Imeri Fatime , Altwegg Martin , Nadal David 
Published: July 2002

ABSTRACT

Streptococcus pneumoniae
is an important cause of community-acquired pneumonia. However, in this setting the diagnostic sensitivity of blood cultures is below 30%. Since during such infections changes in the amounts of
S. pneumoniae
may also occur in the upper respiratory tract, quantification of these bacteria in nasopharnygeal secretions (NPSs) may offer a suitable diagnostic approach. Real-time PCR offers a sensitive, efficient, and routinely reproducible approach to quantification. Using primers and a fluorescent probe specific for the pneumolysin gene, we were able to detect DNA from serial dilutions of
S. pneumoniae
cells in which the quantities of DNA ranged from the amounts extracted from 1 to 10
6
cells. No difference was noted when the same DNA was mixed with DNA extracted from NPSs shown to be deficient of
S. pneumoniae
following culture, suggesting that this bacterium can be detected and accurately quantitated in clinical samples. DNAs from
Haemophilus influenzae
,
Moraxella catarrhalis
, or alpha-hemolytic streptococci other than
S. pneumoniae
were not amplified or were only weakly amplified when there were ≥10
6
cells per reaction mixture. When the assay was applied to NPSs from patients with respiratory tract infections, the assay performed with a sensitivity of 100% and a specificity of up to 96% compared to the culture results. The numbers of
S. pneumoniae
organisms detected by real-time PCR correlated with the numbers detected by semiquantitative cultures. A real-time PCR that targeted the pneumolysin gene provided a sensitive and reliable means for routine rapid detection and quantification of
S. pneumoniae
present in NPSs. This assay may serve as a tool to study changes in the amounts of
S. pneumoniae
during lower respiratory tract infections.
Type IV Longus Pilus of Enterotoxigenic
Escherichia coli
: Occurrence and Association with Toxin Types and Colonization Factors among Strains Isolated in Argentina
Authors: Pichel Mariana G. , Binsztein Norma , Qadri Firdausi , Girón Jorge A. 
Published: July 2002

ABSTRACT

The longus type IV pilus structural gene (
lngA
) was sought among 217 clinical enterotoxigenic
Escherichia coli
(ETEC) strains isolated in Argentina.
lngA
was present in 20.7% of the isolates and was highly associated with ETEC producing heat-stable toxin and the most common colonization factors. The prevalence of longus among ETEC strains in Argentina was comparable to that of colonization factor antigen I (CFA/I), CFA/II, and CFA/IV in other regions of the world.
GP5+/6+ PCR followed by Reverse Line Blot Analysis Enables Rapid and High-Throughput Identification of Human Papillomavirus Genotypes
Authors: van den Brule Adriaan J. C. , Pol René , Fransen-Daalmeijer Nathalie , Schouls Leo M. , Meijer Chris J. L. M. , Snijders Peter J. F. 
Published: July 2002

ABSTRACT

In this study, we developed a simple and fast typing procedure for 37 mucosotropic human papillomavirus (HPV) types using a nonradioactive reverse line blotting (RLB) procedure for general primer (GP5+/6+) PCR products. This system has the advantages not only that in a simple format, up to 42 PCR products can be simultaneously typed per membrane per day, but also that after stripping, the membranes can be easily rehybridized at least 15 times without a loss of signal. RLB appeared highly specific, and its sensitivity was identical to that of conventional typing performed with type-specific oligonucleotide probes in an enzyme immunoassay (EIA). The performance of RLB typing was evaluated with samples of HPV-positive cervical scrapings (
n
= 196) and biopsies of cervical premalignant lesions (
n
= 100). The distribution of HPV genotypes detected in these samples was in line with the distribution expected on the basis of literature data. In addition, RLB and EIA typing procedures were compared for the typing of high-risk HPV types in GP5+/6+ PCR products of 210 cervical scrapings from high-risk HPV-positive women who participated in a population-based screening program. The typing procedures had an excellent overall agreement rate of 96.5% (kappa value, 0.77). RLB was successful in detecting multiple HPV infections as well as single infections. In conclusion, the GP5+/6+ PCR-RLB procedure appeared to be a reliable and simple approach that may be of great value for large epidemiological studies, population-based cervical cancer screening programs, and vaccination trials that require high-throughput HPV typing.
Detection of Mammalian Reovirus RNA by Using Reverse Transcription-PCR: Sequence Diversity within the λ3-Encoding L1 Gene
Authors: Leary Thomas P. , Erker James C. , Chalmers Michelle L. , Cruz Andrea T. , Wetzel J. Denise , Desai Suresh M. , Mushahwar Isa K. , Dermody Terence S. 
Published: July 2002

ABSTRACTReoviruses infect virtually all mammalian species, and infection of humans is associated with mild gastrointestinal or upper respiratory illnesses. To improve reovirus detection strategies, we developed a reverse transcription-PCR technique to amplify a fragment of the reovirus L1 gene segment. This assay was capable of detecting 44 of 44 reovirus field isolate strains and was sufficiently sensitive to detect nearly a single viral particle (1.16 ± 0.13) per PCR of prototype strain type 3 Dearing. Pairwise comparisons of the 44 partial L1 gene sequences revealed that nucleotide variability ranged from 0 to 24.7%, with most of the nucleotide polymorphism occurring at synonymous positions. Phylogenetic trees generated from amplified L1 gene sequences suggest that multiple alleles of the L1 gene cocirculate in nature and that genetic diversity of the L1 gene is largely independent of the host species, geographic locale, or date of isolation. Phylogenetic trees constructed from the L1 gene sequences are distinct from those constructed from the four reovirus S-class gene segments, which supports the hypothesis that reovirus gene segments reassort in nature. This study establishes a new sensitive and specific technique for the identification of mammalian reoviruses and enhances our understanding of reovirus evolution.
Profile of
Salmonella enterica
subsp.
enterica
(Subspecies I) Serotype 4,5,12:i:− Strains Causing Food-Borne Infections in New York City
Authors: Agasan Alice , Kornblum John , Williams George , Pratt Chi-Chi , Fleckenstein Phylis , Wong Marie , Ramon Alex 
Published: July 2002

ABSTRACT

Strains of newly emerging
Salmonella enterica
subsp.
enterica
(subspecies I) serotype 4,5,12:i:− causing food-borne infections, including a large food poisoning outbreak (
n
= 86) characterized by persistent diarrhea (14% bloody), abdominal pain, fever, and headache, were examined. The organisms were found in the stool samples from the patients. The biochemical profile of the organisms is consistent with that of
S. enterica
subsp. I serotypes, except for decreased dulcitol (13%) and increased inositol (96%) utilization. Twenty-eight percent of the strains showed resistance to streptomycin, sulfonamides, or tetracycline only; all three antimicrobial agents; or these agents either alone or in combination with ampicillin, trimethoprim, and trimethoprim-sulfamethoxazole. None of the serotype 4,5,12:i:− strains showed resistance or decreased susceptibility to chloramphenicol or ciprofloxacin. On pulsed-field gel electrophoresis (PFGE), the strains showed 11 or 12 resolvable genomic fragments with 18 banding patterns and three PFGE profile (PFP) clusters (i.e., PFP/A, PFP/B, and PFP/C). Seventy-five percent of the isolates fingerprinted were closely related (zero to three band differences; similarity [Dice] coefficient, 86 to 100%); 63% of these were indistinguishable from each other (PFP/A
1
). PFP/A
1
was common to all strains from the outbreak and 11 hospital sources. Strains from six other hospitals shared clusters PFP/B and PFP/C. PFP/C
4
, of the environmental isolate, was unrelated to PFP/A and PFP/B. Nine band differences (similarity coefficient, 61%) were noted between PFP/A
1
and PFP/E of the multidrug-resistant
S. enterica
subsp.
enterica
serotype Typhimurium definitive type 104 strains. Whether these emerging
Salmonella
strains represent a monophasic, Dul
−
variant of serotype Typhimurium or
S. enterica
subsp.
enterica
serotype Lagos or a distinct serotype of
S. enterica
subsp. I is not yet known. Some of the phenotypic and genotypic properties of the serotype 4,5,12:i:− strains are described here.
In Vitro Activity of Caspofungin (MK-0991) against
Candida albicans
Clinical Isolates Displaying Different Mechanisms of Azole Resistance
Authors: Bachmann Stefano P. , Patterson Thomas F. , López-Ribot José L. 
Published: July 2002

ABSTRACT

Caspofungin inhibits the synthesis of 1,3-β-
d
-glucan, a key step in fungal cell wall biosynthesis. Here we report on its potent in vitro activity (MIC at which 90% of the isolates tested are inhibited = 1 μg per ml of RPMI medium) against 32
Candida albicans
fluconazole-susceptible and -resistant clinical isolates irrespective of the underlying resistance mechanism (alterations in
ERG11
and/or upregulation of
MDR
and
CDR
genes encoding efflux pumps) and provide further evidence that caspofungin is not a substrate for multidrug transporters.
A Novel Polyomavirus (Goose Hemorrhagic Polyomavirus) Is the Agent of Hemorrhagic Nephritis Enteritis of Geese
Authors: Guerin Jean-Luc , Gelfi Jacqueline , Dubois Luc , Vuillaume Aimé , Boucraut-Baralon Corine , Pingret Jean-Luc 
Published: July 2002

ABSTRACT

We have identified the etiological agent of hemorrhagic nephritis enteritis of geese (HNEG), a fatal disease of European geese. HNEG has been recognized in almost all goose breeding areas, with an epizootic pattern, and up to now, the infectious agent has remained unknown. In order to identify the causative agent, infected tissues from HNEG-affected geese were inoculated to 1-day-old goslings, which then developed clinical signs typical of HNEG. Tissue homogenates from these birds were subjected to Freon extraction followed by sucrose density gradient ultracentrifugation. The resulting main band was examined by electron microscopy and consisted of spherical, naked, papovavirus-like particles approximately 45 nm in diameter. The virus was isolated and propagated in goose kidney cell primary culture. Tissue- or culture-purified virus allowed the experimental reproduction of the disease in goslings. Random PCR amplification of viral nucleic acid produced a 1,175-bp fragment which was shown to be associated with field samples collected from geese affected by HNEG on commercial farms in France. Sequence analysis of the PCR product revealed a unique open reading frame, showing 63 to 72% amino acid similarity with the major capsid protein (VP1) of several polyomaviruses. Finally, based on phylogenetic analysis, we conclude that the causative agent of HNEG is closely related to but clearly distinct from other polyomaviruses; we thus have named this newly identified virus
Goose hemorrhagic polyomavirus
.