bluuebunny/crossref_metadata_2025_split huggingface dataset:
Identification ofListeria monocytogenesGenes Expressed in Response to Growth at Low Temperature
Authors: Liu Siqing , Graham James E. , Bigelow Lance , Morse Philip D. , Wilkinson Brian J. 
Published: July 2002

ABSTRACTListeria monocytogenesis a food-borne bacterial pathogen that is able to grow at refrigeration temperatures. To investigate microbial gene expression associated with cold acclimation, we used a differential cDNA cloning procedure known as selective capture of transcribed sequences (SCOTS) to identify bacterial RNAs that were expressed at elevated levels in bacteria grown at 10°C compared to those grown at 37°C. A total of 24 different cDNA clones corresponding to open reading frames in theL. monocytogenesstrain EGD-e genome were obtained by SCOTS. These included cDNAs forL. monocytogenesgenes involved in previously described cold-adaptive responses (flaAandflp), regulatory adaptive responses (rpoN,lhkA,yycJ,bglG,adaB, andpsr), general microbial stress responses (groEL,clpP,clpB,flp, andtrxB), amino acid metabolism (hisJ,trpG,cysS, andaroA), cell surface alterations (fbp,psr, andflaA), and degradative metabolism (eutB,celD, andmleA). Four additional cDNAs were obtained corresponding to genes potentially unique toL. monocytogenesand showing no significant similarity to any other previously described genes. Northern blot analyses confirmed increased steady-state levels of RNA for all members of a subset of genes examined during growth at a low temperature. These results indicated thatL. monocytogenesacclimation to growth at 10°C likely involves amino acid starvation, oxidative stress, aberrant protein synthesis, cell surface remodeling, alterations in degradative metabolism, and induction of global regulatory responses.
Formation of Protoplasts from Cultured Tobacco Cells and
Arabidopsis thaliana
by the Action of Cellulosomes and Pectate Lyase from
Clostridium cellulovorans
Authors: Tamaru Yutaka , Ui Sadaharu , Murashima Koichiro , Kosugi Akihiko , Chan Helen , Doi Roy H. , Liu Bo 
Published: July 2002

ABSTRACT

The crude culture supernatants from
Clostridium cellulovorans
were tested for their ability to convert plant cells to protoplasts. The supernatants readily released protoplasts from cultured tobacco cells and
Arabidopsis thaliana
. The crude culture supernatant from pectin-grown cells was more active than supernatants from glucose-, cellobiose-, xylan-, and locust bean gum-grown cells. After removal of cellulosomes, the crude culture supernatant lost its protoplast formation activity. The protoplast formation activity of the crude culture supernatant from
C. cellulovorans
was more effective than those of commercial enzymes based on protein content.
Empirical and Theoretical Bacterial Diversity in Four Arizona Soils
Authors: Dunbar John , Barns Susan M. , Ticknor Lawrence O. , Kuske Cheryl R. 
Published: July 2002

ABSTRACT

Understanding patterns of biodiversity in microbial communities is severely constrained by the difficulty of adequately sampling these complex systems. We illustrate the problem with empirical data from small surveys (200-member 16S rRNA gene clone libraries) of four bacterial soil communities from two locations in Arizona. Among the four surveys, nearly 500 species-level groups (

Dunbar et al.,
Appl. Environ. Microbiol.
65
:
662
-1669,
1999

) and 21 bacterial divisions were documented, including four new candidate divisions provisionally designated SC1, SC2, SC3, and SC4. We devised a simple approach to constructing theoretical null models of bacterial species abundance. These null models provide, for the first time, detailed descriptions of soil bacterial community structure that can be used to guide experimental design. Models based on a lognormal distribution were consistent with the observed sizes of the four communities and the richness of the clone surveys. Predictions from the models showed that the species richness of small surveys from complex communities is reproducible, whereas the species composition is not. By using the models, we can now estimate the required survey scale to document specified fractions of community diversity. For example, documentation of half the species in each model community would require surveys of 16,284 to 44,000 individuals. However, quantitative comparisons of half the species in two communities would require surveys at least 10-fold larger for each community.
Antigenic and Genetic Characterization of Lipoprotein LppQ fromMycoplasma mycoidessubsp.mycoidesSC
Authors: Abdo El-Mostafa , Nicolet Jacques , Frey Joachim 
Published: July 2002

ABSTRACTLipoprotein LppQ, a predominant 48-kDa antigen, and its corresponding gene,lppQ, were characterized inMycoplasma mycoidessubsp.mycoidesSC, the etiological agent of contagious bovine pleuropneumonia. ThelppQgene is specific toM. mycoidessubsp.mycoidesSC and was found in the type strain and in field strains isolated in Europe, Africa, and Australia, as well as in vaccinal strains. LppQ is encoded as a precursor with a consensus sequence for prokaryotic signal peptidase II and a lipid attachment site. The leader sequence shows significant prominent transmembrane helix structure with a predicted outside-to-inside helix formation capacity. The N-terminal domain of the mature LppQ was shown to be surface exposed. It induced a strong, specific, early, and persistent immune response in naturally and experimentally infected animals. The C-terminal domain of LppQ possesses an integral membrane structure built up of repeated units, rich in hydrophobic and aromatic amino acids, which have a pore formation potential. A recombinant peptide representing the N-terminal domain of LppQ was obtained by site-directed mutagenesis of nineMycoplasma-specific TGA (Trp) codons into universal TGG (Trp) codons and expression inEscherichia colihosts. It was used for serodetection of cattle infected withM. mycoidessubsp.mycoidesSC, in which it was detected postinfection for significantly longer than conventional serological test reactions.
Helicobacter pylori
Intrafamilial Infections: Change in Source of Infection of a Child from Father to Mother after Eradication Therapy
Authors: Taneike Ikue , Tamura Yukiko , Shimizu Toshiaki , Yamashiro Yuichiro , Yamamoto Tatsuo 
Published: July 2002

ABSTRACT

Biopsy specimens of the antrum and corpus were obtained from four
Helicobacter pylori
-infected members of a family and from the same boy (son 1) in whom the infection reappeared after simultaneous successful eradication treatment of three family members, excluding the mother. A total of 18 to 60
H. pylori
isolates were obtained from each specimen and subjected to rRNA gene restriction pattern analysis. The father's isolates and the initial isolates from son 1 showed the same
Hin
dIII type, which was divided into three
Hae
III subtypes. Isolates from the mother and a brother (son 2) and posttreatment isolates from son 1 showed a distinct
Hin
dIII type (with one minor subtype), which was divided into six
Hae
III subtypes. All subtypes of the initial isolates from son 1 were present in the father's isolates, and all subtypes of the posttreatment isolates from son 1 were present in the mother's isolates but not in son 2's. Electron microscopic analysis of the biopsy specimens demonstrated extremely high levels of
H. pylori
colonization in the father's gastric mucosa.
H. pylori
adherence with a ruffle formation was also demonstrated. The findings suggest that son 1 was infected initially with the
H. pylori
strain of the father and son 2 was infected with the
H. pylori
strain of the mother and that after eradication therapy son 1 was reinfected with the
H. pylori
strain of the mother, who did not undergo eradication therapy.
Comparison of Chemicon SimulFluor Direct Fluorescent Antibody Staining with Cell Culture and Shell Vial Direct Immunoperoxidase Staining for Detection of Herpes Simplex Virus and with Cytospin Direct Immunofluorescence Staining for Detection of Varicella-Zoster Virus
Authors: Chan Edward L. , Brandt Ken , Horsman Greg B. 
Published: July 2002

ABSTRACT
A new rapid direct immunofluorescence assay, the SimulFluor direct fluorescent-antibody (DFA) assay, which can simultaneously detect herpes simplex virus types 1 and 2 (HSV-1 and -2) and varicella-zoster virus (VZV), was evaluated in comparison with our current standard procedures of (i) shell vial direct immunoperoxidase (shell vial IP) staining and cell culture for detection of HSV and (ii) cytospin DFA staining for VZV detection. A total of 517 vesicular, oral, genital, and skin lesion specimens were tested by all three procedures. For HSV detection, the SimulFluor DFA assay had an overall sensitivity, specificity, positive predictive value, and negative predictive value of 80.0, 98.3, 92.3, and 95.1%, respectively, when compared to culture. Shell vial IP staining had a sensitivity, specificity, positive predictive value, and negative predictive value of 87.6, 100, 100, and 96.9%, respectively, when compared with cell culture. The SimulFluor DFA assay, however, offers same-day, 1.5-hours results versus a 1- to 2-day wait for shell vial IP staining results and a 1- to 6-day wait for culture results for HSV. For VZV detection SimulFluor DFA staining detected 27 positive specimens as compared to 31 by our standard cytospin DFA technique—a correlation of 87.1%. A positive SimulFluor reaction for VZV is indicated by yellow-gold fluorescence compared to the bright apple-green fluorescence observed by cytospin DFA staining. There is no difference in turnaround time between the two assays. The SimulFluor DFA assay is a rapid immunofluorescence assay that can detect 80% of the HSV-positive specimens and 87% of the VZV-positive specimens with a 1.5-h turnaround time.
Selective In Vivo Depletion of CD4+T Lymphocytes with Anti-CD4 Monoclonal Antibody during Acute Infection of Calves withAnaplasma marginale
Authors: Valdez Reginald A. , McGuire Travis C. , Brown Wendy C. , Davis William C. , Jordan Jeffrey M. , Knowles Donald P. 
Published: July 2002

ABSTRACTTo investigate the in vivo role of CD4+T lymphocytes during acute anaplasmosis, thymectomized calves were selectively depleted of CD4+T lymphocytes by treatment with anti-CD4 monoclonal antibody (MAb) and were then infected with the Florida strain ofAnaplasma marginalein two sequential experiments (experiments 1 and 2). Treatment of thymectomized calves with a total of 5.0 mg of anti-CD4 MAb/kg of body weight during the 1st week followed by 0.3-mg/kg doses administered twice weekly for 7 weeks resulted in significant depletion of CD3+CD4+and CD4+CD45R+(naive) T lymphocytes from blood, spleen, and peripheral lymph nodes for the duration of the 8-week study, compared to the results for thymectomized control calves treated with a subclass-matched MAb. All calves became parasitemic and pyretic following experimental infection withA. marginale, and decreases in packed cell volume (PCV) coincided with peak parasitemia. No significant differences in PCV or parasitemia were observed between treatment groups. Thymectomized calves treated with anti-CD4 MAb were able to mount an anti-A. marginaleantibody response, although in experiment 2, anti-CD4 MAb-treated calves had four- to sixfold lower immunoglobulin G1 (IgG1) and no detectable IgG2 anti-A. marginalemajor surface protein 2-specific antibody titers compared to thymectomized control calves treated with a subclass-matched MAb. At the level of CD4+-T-lymphocyte depletion achieved and experimental anaplasmosis induced, thymectomized anti-CD4 MAb-treated calves were able to control acute anaplasmosis. This was in contrast to the prediction that significant depletion of CD4+T lymphocytes would abrogate resistance to acute infection.
Development, Evaluation, and Application of Lateral-Flow Immunoassay (Immunochromatography) for Detection of Rotavirus in Bovine Fecal Samples
Authors: Al-Yousif Yousif , Anderson Joe , Chard-Bergstrom Cindy , Kapil Sanjay 
Published: July 2002

ABSTRACTA lateral-flow immunoassay (LFT) was developed to detect bovine rotavirus in fecal samples. Using samples (n= 74) from diarrheic calves, a comparison of the LFT with a commercial latex agglutination test (LAT) and transmission electron microscopy (EM) was conducted. When EM was used as the reference method, initial studies of 29 samples indicated 70 and 80% sensitivities of the LFT and LAT, respectively, with both being 100% specific. When the LAT was the reference test, the LFT was 75% sensitive and 91% specific. Additional specimens (n= 45) were tested by the LFT and LAT alone, and results were identical for both methods.
Lung Infections Associated with Cystic Fibrosis
Authors: Lyczak Jeffrey B. , Cannon Carolyn L. , Pier Gerald B. 
Published: July 2002

SUMMARYWhile originally characterized as a collection of related syndromes, cystic fibrosis (CF) is now recognized as a single disease whose diverse symptoms stem from the wide tissue distribution of the gene product that is defective in CF, the ion channel and regulator, cystic fibrosis transmembrane conductance regulator (CFTR). Defective CFTR protein impacts the function of the pancreas and alters the consistency of mucosal secretions. The latter of these effects probably plays an important role in the defective resistance of CF patients to many pathogens. As the modalities of CF research have changed over the decades from empirical histological studies to include biophysical measurements of CFTR function, the clinical management of this disease has similarly evolved to effectively address the ever-changing spectrum of CF-related infectious diseases. These factors have led to the successful management of many CF-related infections with the notable exception of chronic lung infection with the gram-negative bacterium Pseudomonas aeruginosa. The virulence of P. aeruginosa stems from multiple bacterial attributes, including antibiotic resistance, the ability to utilize quorum-sensing signals to form biofilms, the destructive potential of a multitude of its microbial toxins, and the ability to acquire a mucoid phenotype, which renders this microbe resistant to both the innate and acquired immunologic defenses of the host.
Interleukin-4 (IL-4) and IL-13 Signaling Pathways Do Not RegulateBorrelia burgdorferi-Induced Arthritis in Mice: IgG1 Is Not Required for Host Control of Tissue Spirochetes
Authors: Potter Melissa R. , Noben-Trauth Nancy , Weis John H. , Teuscher Cory , Weis Janis J. 
Published: July 2002

ABSTRACTPrevious studies have suggested that interleukin-4 (IL-4) has a protective effect in host defense toBorrelia burgdorferiinfection, both in limiting the severity of arthritis and in controlling spirochete numbers in tissues, and a mapping study revealed suggestive linkage to a cluster of genes on mouse chromosome 11, including the genes for IL-4 and IL-13. In contrast, other studies have questioned the importance of IL-4. In this study the involvement of IL-4 in murine Lyme disease was examined in C57BL/6J and BALB/cJ mice with targeted disruptions in the IL-4 gene, the IL-4Rα chain gene, or both. A spectrum of arthritis severity was seen in BALB/cJ mice, and ablation of IL-4, IL-4Rα, or both had no effect on the overall severity of arthritis as determined by joint swelling and histopathology. Wild-type C57BL/6J mice exhibited mild to moderate arthritis, and ablation of IL-4 again had no effect on arthritis severity. IL-4- and IL-4Rα-deficient mice produced extremely low levels of immunoglobulin G1 (IgG1) and showed increased production of IgG2b. This shift in immunoglobulin isotype had no effect on the host's ability to control spirochete growth in either strain of mouse, as determined by PCR detection ofB. burgdorferiDNA from heart and ankle tissues. In summary, the IL-4-IL-4Rα pathway, including IL-13 signaling, neither limits arthritis severity nor is required for control of spirochete growth duringB. burgdorferiinfection of mice. Furthermore, the IgG1 isotype is not required to controlB. burgdorfericell numbers in tissues. These findings suggest the host defense againstB. burgdorferiinfection is not dependent on the Th1-Th2 paradigm of T-cell responses.
Interleukin-10 Modulates Proinflammatory Cytokines in the Human Monocytic Cell Line THP-1 Stimulated withBorrelia burgdorferiLipoproteins
Authors: Murthy P. K. , Dennis Vida A. , Lasater Barbara L. , Philipp Mario T. 
Published: July 2002

ABSTRACTWe determined previously that lipoproteins ofBorrelia burgdorferistimulate inflammatory and anti-inflammatory cytokines (interleukin-10 [IL-10]) in monocytes. IL-10 could have an effect on innate and acquired immune responses toB. burgdorferiand influence the magnitude of the infectious inoculum and disease outcome. To understand the mechanism(s) of IL-10 action during early infection, when innate immunity expressed chiefly by skin macrophages is key, we investigated the effect of exogenous and endogenous IL-10 on the production of the macrophage-derived cytokines IL-6, IL-1β, IL-12, and tumor necrosis factor alpha (TNF-α). We used the THP-1 human monocytic cell line and recombinant lipidated OspA (L-OspA) as the model target cell and stimulant, respectively. To determine the kinetics of cytokine production by THP-1 cells, we stimulated them with L-OspA and also with heat-killedB. burgdorfericells (HBb) and lipopolysaccharide (LPS). Exogenous IL-10 dampened production of inflammatory cytokines, as elicited by lipoproteins. The inhibition of endogenous IL-10 function by anti-IL-10 antibody reduced the production of IL-12 and IL-6 but not that of IL-1β and TNF-α. An inspection of the kinetics of cytokine production clarified this finding. TNF-α was produced prior to, and IL-β was produced at the same time as, IL-10, whereas IL-6 and IL-12 were produced later. HBb, LPS, and L-OspA yielded similar kinetics of cytokine production. This result reinforces the notion that lipoproteins are the functional molecules in HBb and perhaps in vivo. It indicates also that signaling pathways utilized by LPS and lipoproteins may be extensively shared. The results are consistent with a major role played by IL-10 in controlling the initial phase of infection with this spirochete.
Phagocytic Uptake ofEncephalitozoon cuniculiby Nonprofessional Phagocytes
Authors: Couzinet Sabine , Cejas Elisabeth , Schittny Johannes , Deplazes Peter , Weber Rainer , Zimmerli Stefan 
Published: July 2002

ABSTRACTEncephalitozoon cuniculiis an obligate intracellular, spore-forming parasite belonging to the microsporidia that can cause disseminated infection in immunocompromised persons.E. cuniculispores infect host cells by germination, i.e., by explosively everting the polar filament, through which the spore contents (sporoplasms) are subsequently injected into the cytoplasm. In addition, we observed intracellular, nongerminated spores in various nonprofessional phagocytes. In MRC5 cells, the number of internalized spores was approximately 10-fold higher than the number of injected sporoplasms. Compared to the rate of uptake by human monocyte-derived macrophages, internalization rates by A549 cells, MRC5 cells, and 293 cells were 0.6, 4.4, and 22.2%, respectively. The mechanism of uptake was studied in MRC5 cells. Killed spores were internalized at the same rate as live spores, indicating that nongerminated parasites do not actively participate in cell entry. Cytochalasin D inhibited uptake of spores by 95%, demonstrating an actin-dependent process. By electron and epifluorescence microscopy, intracellular spores were found in a tightly fitting membrane-bound compartment. The vacuole containing the spores was positive for the lysosomal membrane protein LAMP-1 and colocalized with the late endosomal-lysosomal content marker rhodamine dextran. Our results show that, in addition to the unique way in which microsporidia infect cells,E. cuniculispores enter nonprofessional phagocytes by phagocytosis and traffic into a late endosomal-lysosomal compartment.
Comparative Analysis of Antibody Responses against HSP60, Invariant Surface Glycoprotein 70, and Variant Surface Glycoprotein Reveals a Complex Antigen-Specific Pattern of Immunoglobulin Isotype Switching during Infection byTrypanosoma brucei
Authors: Radwanska Magdalena , Magez Stefan , Michel Alain , Stijlemans Benoît , Geuskens Maurice , Pays Etienne 
Published: July 2002

ABSTRACTDuringTrypanosoma bruceiinfections, the response against the variant surface glycoprotein (VSG) of the parasite represents a major interaction between the mammalian host immune system and the parasite surface. Since immune recognition of other parasite derived factors also occurs, we examined the humoral host response against trypanosome heat shock protein 60 (HSP60), a conserved antigen with an autoimmune character. During experimentalT. bruceiinfection in BALB/c mice, the anti-HSP60 response was induced when parasites differentiated into stumpy forms. This response was characterized by a stage-specific immunoglobulin isotype switching as well as by the induction of an autoimmune response. Specific recognition of trypanosome HSP60 was found to occur during the entire course of infection. Immunoglobulin G2a (IgG2a) and IgG2b antibodies, induced mainly in a T-cell-independent manner, were observed during the first peak of parasitemia, whereas IgG1 and IgG3 antibodies were found at the end of the infection, due to a specific T-cell-mediated response. Comparative analysis of the kinetics of anti-HSP60, anti-invariant surface glycoprotein 70 (ISG70), and anti-VSG antibody responses indicated that the three trypanosome antigens give rise to specific and independent patterns of immunoglobulin isotype switching.
Acquired Immunity toChlamydia pneumoniaeIs Dependent on Gamma Interferon in Two Mouse Strains That Initially Differ in This Respect after Primary Challenge
Authors: Vuola Jenni M. , Puurula Vuokko , Anttila Marjukka , Mäkelä P. Helena , Rautonen Nina 
Published: July 2002

ABSTRACTThe role of gamma interferon (IFN-γ) in aChlamydia pneumoniaemouse model was studied by in vivo neutralization in two inbred mouse strains. During primaryC. pneumoniaeinfection, neutralization of IFN-γ increased both the numbers of bacteria and the pneumonia score in the lungs of C57BL/6 mice but not BALB/c mice. During reinfection, the bacterial counts in the lungs were increased by IFN-γ neutralization in both mouse strains. Thus, the effect of IFN-γ neutralization was dependent on the genetic background in primary infection. However, IFN-γ appeared to be equally important in both mouse strains during reinfection.