bluuebunny/crossref_metadata_2025_split huggingface dataset:
Isolation and Characterization of a Gene Specific to Lager Brewing Yeast That Encodes a Branched-Chain Amino Acid Permease
Authors: Kodama Yukiko , Omura Fumihiko , Ashikari Toshihiko 
Published: July 2002

ABSTRACT

We found two types of branched-chain amino acid permease gene (
BAP2
) in the lager brewing yeast
Saccharomyces pastorianus
BH-225 and cloned one type of
BAP2
gene (Lg-
BAP2
), which is identical to that of
Saccharomyces bayanus
(by-
BAP2
-1). The other
BAP2
gene of the lager brewing yeast (cer-
BAP2
) is very similar to the
Saccharomyces cerevisiae BAP2
gene. This result substantiates the notion that lager brewing yeast is a hybrid of
S. cerevisiae
and
S. bayanus
. The amino acid sequence homology between
S. cerevisiae
Bap2p and Lg-Bap2p was 88%. The transcription of Lg-
BAP2
was not induced by the addition of leucine to the growth medium, while that of cer-
BAP2
was induced. The transcription of Lg-
BAP2
was repressed by the presence of ethanol and weak organic acid, while that of cer-
BAP2
was not affected by these compounds. Furthermore, Northern analysis during beer fermentation revealed that the transcription of Lg-
BAP2
was repressed at the beginning of the fermentation, while cer-
BAP2
was highly expressed throughout the fermentation. These results suggest that the transcription of Lg-
BAP2
is regulated differently from that of cer-
BAP2
in lager brewing yeasts.
In Vivo
23
Na Nuclear Magnetic Resonance Study of Maintenance of a Sodium Gradient in the Ruminal Bacterium
Fibrobacter succinogenes
S85
Authors: Schwaab Véronique , Matheron Christelle , Delort Anne-Marie , Gaudet Geneviève , Forano Evelyne 
Published: July 2002

ABSTRACT

Sodium gradients (ΔpNa) were measured in resting cells of
Fibrobacter succinogenes
by in vivo
23
Na nuclear magnetic resonance using Tm(DOTP)
5−
[thulium(III) 1,4,7,10-tetraazacyclododecane-
N
′,
N
′′,
N
′′′-tetramethylenephosphonate] as the shift reagent. This bacterium was able to maintain a ΔpNa of −55 to −40 mV for extracellular sodium concentrations ranging from 30 to 200 mM. Depletion of Na
+
ions during the washing steps led to irreversible damage (modification of glucose metabolism and inability to maintain a sodium gradient).
Identification and Characterization of a Putative Transcriptional Regulator Controlling the Expression of Fouling Inhibitors in
Pseudoalteromonas tunicata
Authors: Egan Suhelen , James Sally , Kjelleberg Staffan 
Published: July 2002

ABSTRACT

The dark green pigmented marine bacterium
Pseudoalteromonas tunicata
colonizes living surfaces and produces a range of extracellular compounds that inhibit common fouling organisms, including marine invertebrate larvae, algae, bacteria, and fungi. We have observed a positive correlation between the antifouling activity of
P. tunicata
strain D2 and the expression of pigmentation. To address the hypothesis that pigmentation and antifouling may be jointly regulated in this organism and to begin to identify potential regulatory elements, we used transposon mutagenesis to generate a strain of
P. tunicata
deficient in antifouling activity. The data presented here describe the phenotypic and molecular characterization of a nonpigmented transposon mutant strain of
P. tunicata
(D2W2). Analyses of the antifouling capabilities of D2W2 demonstrate that this strain is deficient in the ability to inhibit each of the target fouling organisms. Genetic analysis of D2W2 identified a gene, designated
wmpR
(white mutant phenotype), with high sequence similarity to transcriptional regulators ToxR from
Vibrio cholerae
and CadC from
Escherichia coli
. Two-dimensional polyacrylamide gel electrophoresis analysis revealed that WmpR is essential for the expression of a significant subset of stationary-phase-induced proteins likely to be important for the synthesis of fouling inhibitors. The identification of a gene involved in the regulation of expression of antifouling phenotypes will contribute to the understanding of the interactions between bacteria and other surface-colonizing organisms in the marine environment.
Genomic Subtraction To Identify and Characterize Sequences of Shiga Toxin-Producing
Escherichia coli
O91:H21
Authors: Pradel Nathalie , Leroy-Setrin Sabine , Joly Bernard , Livrelli Valérie 
Published: July 2002

ABSTRACT

To identify Shiga toxin-producing
Escherichia coli
genes associated with severe human disease, a genomic subtraction technique was used with hemolytic-uremic syndrome-associated O91:H21 strain CH014 and O6:H10 bovine strains. The method was adapted to the Shiga toxin-producing
E. coli
genome: three rounds of subtraction were used to isolate DNA fragments specific to strain CH014. The fragments were characterized by genetic support analysis, sequencing, and hybridization to the genome of a collection of Shiga toxin-producing
E. coli
strains. A total of 42 fragments were found, 19 of which correspond to previously identified unique DNA sequences in the enterohemorrhagic
E. coli
EDL933 reference strain, including 7 fragments corresponding to prophage sequences and others encoding candidate virulence factors, such a SepA homolog protein and a fimbrial usher protein. In addition, the subtraction procedure yielded plasmid-related sequences from
Shigella flexneri
and enteropathogenic and Shiga toxin-producing
E. coli
virulence plasmids. We found that lateral gene transfer is extensive in strain CH014, and we discuss the role of genomic mobile elements, especially bacteriophages, in the evolution and possible transfer of virulence determinants.
Development of Monoclonal Antibodies against
Ureaplasma urealyticum
Serotypes and Their Use for Serotyping Clinical Isolates
Authors: Echahidi Fedoua , Muyldermans Gaëtan , Lauwers Sabine , Naessens Anne 
Published: July 2002

ABSTRACT

Monoclonal antibodies (MAbs) against
Ureaplasma urealyticum
serotype 2, 5, 7, 8, 10, 11, 12, and 13 reference strains were developed. The reactivities of these MAbs with the 14 serotype reference strains was verified by colony immunofluorescence assay and Western blot assay. MAbs against serotypes 2, 7, 10, 11, and 12 were serotype specific, whereas MAbs against serotypes 5, 8, and 13 showed cross-reactivity. All MAbs against serotype 5 were cross-reactive with serotype 2, and one showed, in addition, cross-reactivity to serotypes 9 and 10. Mutual cross-reactivities were observed between MAbs against serotypes 8 and 13. The usefulness of the MAbs for the serotyping of
U. urealyticum
strains was evaluated by serotyping 21 selected clinical isolates. A complete set of MAbs (the newly developed MAbs and the previously described MAbs against serotypes 1, 3, 4, 6, 9, and 14) as well as a complete set of polyclonal antibodies (PAbs), PAbs 1 to 14, were used. MAbs were able to identify 18 of 21 isolates including 2 isolates with mixed serotypes. Polyreactivity, which occurred with 19 of the 21 isolates with PAbs, was not observed by the use of MAbs. MAbs seem to be a more valuable tool than PAbs for serotyping and could help in investigating a possible link between the expression or variability of the serotype-specific antigens and pathogenicity.
Molecular Investigation of Transmission of Human Immunodeficiency Virus Type 1 in a Criminal Case
Authors: Machuca Roberto , Jørgensen Louise B. , Theilade Peter , Nielsen Claus 
Published: July 2002

ABSTRACT

Very few criminal cases involving human immunodeficiency virus type 1 (HIV-1) transmission have been described. We report on an HIV-1 transmission case with a child being infected by an HIV-1-positive man. The objective was to determine through molecular epidemiology and phylogenetic analyses whether HIV-1 from the HIV-1-positive man could be the source of infection in the HIV-1-positive child, as claimed by the authorities. We conducted genetic analysis of three different parts of the HIV-1 genome (
gag, pol
, and
env
) by PCR, direct-sequencing, and phylogenetic analyses. We used maximum likelihood, maximum parsimony, and neighbor-joining methods for the phylogenetic analyses to investigate whether the sequences from the man and the child were related. We found that the viral sequences from the man and the child formed separate clusters in all of the phylogenetic analyses compared to the local controls. A unique amino acid deletion was identified in the C2-V3-C3 region of the
env
gene in the virus from the man and the child. These results were used in the criminal court to elucidate whether the virus from the man was related to the virus from the child. In summary, the results from the phylogenetic analyses, the sequence distances between the virus from the man and the virus from the child, and the identification of the unique molecular fingerprint in the
env
gene together indicated that the virus from the man and the virus from the child were epidemiologically linked.
Impaired Bactericidal Activity and Host Resistance toListeria monocytogenesandBorrelia burgdorferiin Rats Administered an Acute Oral Regimen of Ethanol
Authors: Pavia Charles S. , Harris Cynthia M. , Kavanagh Marie 
Published: July 2002

ABSTRACTA rat model was used to examine how ethanol ingestion may interfere with antimicrobial immunity both in vitro and in vivo. Nonimmune Long-Evans rats were given a short-course treatment orally with excessive amounts of ethanol. Their spleens were removed at the time of sacrifice, and separate spleen cell suspensions were prepared and tested in vitro for their ability to kill two bacterial pathogens,Listeria monocytogenesandBorrelia burgdorferi.After the bacteria were mixed separately with various concentrations of spleen cells, it was found that spleen cells from the ethanol-treated rats killed fewer bacteria than matching pair-fed controls, based on counts of the number of cultured CFU (forListeria) or based on microscopic examination (forBorrelia). For the in vivo studies, ethanol-treated and control rats were infected intraperitoneally withListeria, and then, 1 to 3 days later, they were assessed for systemic infection based on the numbers of organisms present in their livers and spleens. Numbers of bacterial CFU for both organs were significantly higher in the group fed ethanol for the first 2 days after listerial challenge. These results support the concept that acute exposure to high levels of ethanol can impair host defense mechanisms, especially those expressed at the cellular level, which could lead to increased susceptibility to certain types of infections.
Attachment ofToxoplasma gondiito a Specific Membrane Fraction of CHO Cells
Authors: Dutta Chaitali , Grimwood Jane , Kasper Lloyd H. 
Published: July 2002

ABSTRACTWe have observed previously that attachment ofToxoplasma gondiito synchronized host cells is considerably increased at the mid-S phase (4 h postrelease). Synchronized CHO host cells at the mid-S phase were fractionated by molecular weight, and the antigens were used to produce a panel of polyclonal mouse antisera. The polyclonal antisera raised against fraction 4 with molecular mass ranging approximately from 18 to 40 kDa significantly reduced attachment to mid-S-phase host cells. Immunofluorescence assays demonstrated strong reactivity to mid-S-phase host cells and identified a number of potential receptors on Western blots. These data indicate that there is a specific host membrane receptor for parasite attachment that is upregulated during the mid-S phase of the host cell cycle.
Cloning of the Gene Encoding a 22-Kilodalton Cell Surface Antigen ofMycobacterium bovisBCG and Analysis of Its Potential for DNA Vaccination against Tuberculosis
Authors: Lefèvre Philippe , Denis Olivier , De Wit Lucas , Tanghe Audrey , Vandenbussche Paul , Content Jean , Huygen Kris 
Published: July 2002

ABSTRACTUsing spleen cells from mice vaccinated with liveMycobacterium bovisBCG, we previously generated three monoclonal antibodies reactive against a 22-kDa protein present in mycobacterial culture filtrate (CF) (K. Huygen et al., Infect. Immun. 61:2687–2693, 1993). These monoclonal antibodies were used to screen anM. bovisBCG genomic library made in phage λgt11. The gene encoding a 233-amino-acid (aa) protein, including a putative 26-aa signal sequence, was isolated, and sequence analysis indicated that the protein was 98% identical with theM. tuberculosisLppx protein and that it contained a sequence 94% identical with theM. leprae38-mer polypeptide 13B3 recognized by T cells from killedM. leprae-immunized subjects. Flow cytometry and cell fractionation demonstrated that the 22-kDa CF protein is also highly expressed in the bacterial cell wall and membrane compartment but not in the cytosol. C57BL/6, C3H, and BALB/c mice were vaccinated with plasmid DNA encoding the 22-kDa protein and analyzed for immune response and protection against intravenousM. tuberculosischallenge. Whereas DNA vaccination induced elevated antibody responses in C57BL/6 and particularly in C3H mice, Th1-type cytokine response, as measured by interleukin-2 and gamma interferon secretion, was only modest, and no protection against intravenousM. tuberculosischallenge was observed in any of the three mouse strains tested. Therefore, the 22-kDa antigen seems to have little potential for a DNA vaccine against tuberculosis, but it may be a good candidate for a mycobacterial antigen detection test.
Construction and Characterization of aSalmonella entericaSerovar Typhimurium Clone Expressing a Salivary Adhesin ofStreptococcus mutansunder Control of the Anaerobically InduciblenirBPromoter
Authors: Huang Yan , Hajishengallis George , Michalek Suzanne M. 
Published: July 2002

ABSTRACTAttenuatedSalmonella entericaserovar Typhimurium has been used for targeted delivery of recombinant antigens to the gut-associated lymphoid tissues. One potential problem associated with this vaccine approach is the likelihood of in vivo instability of the plasmid constructs caused by constitutive hyperexpression of the heterologous immunogen. The aim of this study was to generate and characterize an expression system encoding the saliva-binding region (SBR) ofStreptococcus mutansantigen I/II adhesin, either alone or linked with the mucosal adjuvant cholera toxin A2/B subunits (CTA2/B), under the control of the induciblenirBpromoter. This promoter is activated in an anaerobic environment and within macrophages, which are the primary antigen-presenting cells involved in phagocytosis and processing ofSalmonella. The gene encoding the chimeric SBR-CTA2/B was amplified by PCR using primers containing appropriate restriction sites for subcloning into pTETnirB, which contains thenirBpromoter. The resulting plasmid was introduced into serovar Typhimurium by electroporation. Production of the SBR-CTA2/B chimeric protein under anaerobic conditions was verified by enzyme-linked immunosorbent assay of whole-cell lysates on plates coated with GM1ganglioside and developed with antibodies to SBR. Similar procedures were followed for cloning the gene encoding SBR in serovar Typhimurium undernirBcontrol. Anaerobic expression of SBR was confirmed by Western blotting of whole-cell lysates probed with anti-SBR antibodies. The resulting serovar Typhimurium strains were administered by either the oral or the intranasal route to mice, and colonization was assessed by microbiologic analysis of dissociated spleens, Peyer's patches (PP), and nasal tissues. High numbers of the recombinant strains persisted in PP and spleen for at least 21 days following oral challenge. A single intranasal administration of theSalmonellaclones to mice also resulted in the colonization of the nasal tissues by the recombinant bacteria. Salmonellae were recovered from nasal lymphoid tissues, superficial lymph nodes, internal jugular lymph nodes, PP, and spleens of mice for at least 21 days after challenge. This study provides quantitative evidence for colonization bySalmonellastrains expressing a recombinant protein under the control of the induciblenirBpromoter in PP or nasal tissues following a single oral or nasal administration of the bacteria, respectively.
Identification and Genetic Characterization of
Haemophilus influenzae
Genetic Island 1
Authors: Chang Chih-Ching , Gilsdorf Janet R. , DiRita Victor J. , Marrs Carl F. 
Published: July 2002

ABSTRACT

The type b capsule of pathogenic
Haemophilus influenzae
is a critical factor for
H. influenzae
survival in the blood and the establishment of invasive infections. Other pathogenic factors associated with type b strains may also play a role in invasion and sustained bacteremia, leading to the seeding of deep tissues. The gene encoding haemocin is the only noncapsular gene found to be specific to type b strains until now. Here we report the discovery of an approximately 16-kb genetic locus, HiGI1, that is present primarily in type b strains. Pulsed-field gel electrophoresis and Southern hybridization were used to map this new locus between
secG
(HI0445) and
fruA
(HI0446), which are contiguous in Rd, a nonpathogenic derivative of a serotype d strain. It is inserted at the 3′ end of tRNA
4
Leu
and has regions whose G+C content differs from the average genomic G+C content of
H. influenzae
. An integrase gene, which encodes a CP4-57 like integrase, is located downstream of tRNA
4
Leu
. Hybridization probes based on the sequences within the HiGI1 locus have been used to screen 61
H. influenzae
strains (2 type a, 22 type b, 2 type c, 1 type d, 3 type e, 7 type f, and 21 nontypeable
H. influenzae
[NTHi]) from our collection. This HiGI1 locus exists in all 22 type b strains and two NTHi strains and is likely to have been acquired by an ancestral type b strain.
The Metalloproteinase Inhibitor GI5402 Inhibits Endotoxin-Induced Soluble CD27 and CD16 Release in Healthy Humans
Authors: Dekkers Pascale E. P. , ten Hove Tessa , Lauw Fanny N. , Koene Harry R. , Lumley Philip , van Deventer Sander J. H. , van der Poll Tom 
Published: July 2002

ABSTRACTMetalloproteinases have been implicated in the cleavage of a number of cell surface immune receptors. Oral administration of the metalloproteinase inhibitor GI5402 attenuated the release of soluble CD27 and CD16 into the circulation after intravenous endotoxin injection in healthy humans.
Construction and Characterization of
Haemophilus ducreyi
Lipooligosaccharide (LOS) Mutants Defective in Expression of Heptosyltransferase III and β1,4-Glucosyltransferase: Identification of LOS Glycoforms Containing Lactosamine Repeats
Authors: Filiatrault Melanie J. , Gibson Bradford W. , Schilling Birgit , Sun Shuhua , Munson Robert S. , Campagnari Anthony A. 
Published: July 2002

ABSTRACT

To begin to understand the role of the lipooligosaccharide (LOS) molecule in chancroid infections, we constructed mutants defective in expression of glycosyltransferase genes. Pyocin lysis and immunoscreening was used to identify a LOS mutant of
Haemophilus ducreyi
35000. This mutant, HD35000R, produced a LOS molecule that lacked the monoclonal antibody 3F11 epitope and migrated with an increased mobility on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Structural studies indicated that the principal LOS glycoform contains lipid A, Kdo, and two of the three core heptose residues. HD35000R was transformed with a plasmid library of
H. ducreyi
35000 DNA, and a clone producing the wild-type LOS was identified. Sequence analysis of the plasmid insert revealed one open reading frame (ORF) that encodes a protein with homology to the WaaQ (heptosyltransferase III) of
Escherichia coli
. A second ORF had homology to the LgtF (glucosyltransferase) of
Neisseria meningitidis
. Individual isogenic mutants lacking expression of the putative
H. ducreyi
heptosyltransferase III, the putative glucosyltransferase, and both glycosyltransferases were constructed and characterized. Each mutant was complemented with the representative wild-type genes in
trans
to restore expression of parental LOS and confirm the function of each enzyme. Matrix-assisted laser desorption ionization mass spectrometry and SDS-PAGE analysis identified several unique LOS glycoforms containing di-, tri-, and poly-
N
-acetyllactosamine repeats added to the terminal region of the main LOS branch synthesized by the heptosyltransferase III mutant. These novel
H. ducreyi
mutants provide important tools for studying the regulation of LOS assembly and biosynthesis.
Antigen Specificity of T-Cell Response toMycobacterium aviumInfection in Mice
Authors: Pais Teresa F. , Cunha Joana Feijó , Appelberg Rui 
Published: July 2002

ABSTRACTT cells fromMycobacterium avium-infected C57BL/6 mice reacted to culture filtrate, envelope, and cytosol proteins and to fractions obtained from these proteins. Multiple targets were recognized, such as 29- to 45-kDa and <21-kDa antigens of the culture filtrate, antigens of around 30 kDa in the envelope and cytosol, and 45- to 116-kDa proteins in the envelope.
Role ofNramp1Deletion inChlamydiaInfection in Mice
Authors: Pal Sukumar , Peterson Ellena M. , de la Maza Luis M. 
Published: July 2002

ABSTRACTElicited macrophages from 129sv mice with a functional deletion of the natural-resistance-associated macrophage protein 1 gene (Nramp1) were shown to be as susceptible as wild-type mice to infection with theChlamydia trachomatismouse pneumonitis and L3 serovars and toChlamydia pneumoniae. Furthermore, the two groups of mice were shown to be similarly susceptible to an intranasal infection with these microorganisms. In conclusion, theNramp1gene does not appear to play a major role in the regulation of the susceptibility of mice to a chlamydial infection.
The Major Acute-Phase Protein, Serum Amyloid P Component, in Mice Is Not Involved in Endogenous Resistance against Tumor Necrosis Factor Alpha-Induced Lethal Hepatitis, Shock, and Skin Necrosis
Authors: Van Molle Wim , Hochepied Tino , Brouckaert Peter , Libert Claude 
Published: July 2002

ABSTRACTThe proinflammatory cytokine tumor necrosis factor alpha (TNF-α) induces lethal hepatitis when injected intod-(+)-galactosamine-sensitized mice on the one hand or systemic inflammatory response syndrome (SIRS) in normal mice on the other hand. We studied whether serum amyloid P component (SAP), the major acute-phase protein in mice, plays a protective role in both lethal models. For this purpose, we used SAP0/0mice generated by gene targeting. We studied the lethal response of SAP0/0or SAP+/+mice to both lethal triggers but found no differences in the sensitivity of both types of mice. We also investigated whether SAP is involved in establishing two types of endogenous protection: one using a single injection of interleukin-1β (IL-1β) for desensitization and clearly involving a liver protein, the other by tolerizing mice for 5 days using small doses of human TNF-α. Although after IL-1β or after tolerization the SAP levels in the serum had risen fourfold in the control mice and not in the SAP0/0mice, the same extents of desensitization and tolerization were achieved. Finally, we observed that the induction of hemorrhagic necrosis in the skin of mice by two consecutive local injections with TNF-α was not altered in SAP0/0mice. We conclude that the presence or absence of SAP has no influence on the sensitivity of mice to TNF-α-induced hepatitis, SIRS, and hemorrhagic necrosis or on the endogenous protective mechanisms of desensitization or tolerization.