bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interactions among Plant Species and Microorganisms in Salt Marsh Sediments
Authors: Burke David J. , Hamerlynck Erik P. , Hahn Dittmar 
Published: July 2002

ABSTRACT

The interactions among
Spartina patens
and sediment microbial populations and the interactions among
Phragmites australis
and sediment microbial populations were studied at monotypic sites in Piermont Marsh, a salt marsh of the Hudson River north of New York, N.Y., at key times during the growing season. Arbuscular mycorrhizal fungi (AMF) effectively colonized
S. patens
but not
P. australis
, and there were seasonal increases and decreases that coincided with plant growth and senescence (17 and 6% of the
S. patens
root length were colonized, respectively). In sediment samples from the
Spartina
site, the microbial community and specific bacterial populations were at least twice as large in terms of number and biomass as the microbial community and specific bacterial populations in sediment samples from the
Phragmites
site, and peak values occurred during reproduction. Members of the domain
Bacteria
, especially members of the α-, γ-, and δ-subdivisions of the
Proteobacteria
, were the most abundant organisms at both sites throughout the growing season. The populations were generally more dynamic in samples from the
Spartina
site than in samples from the
Phragmites
site. No differences between the two sites and no differences during the growing season were observed when restriction fragment length polymorphism analyses of
nifH
amplicons were performed in an attempt to detect shifts in the diversity of nitrogen-fixing bacteria. Differences were observed only in the patterns generated by PCR or reverse transcription-PCR for samples from the
Spartina
site, suggesting that there were differences in the overall and active populations of nitrogen-fixing bacteria. Regression analyses indicated that there was a positive interaction between members of the δ-subdivision of the
Proteobacteria
and root biomass but not between members of the δ-subdivision of the
Proteobacteria
and macroorganic matter at both sites. In samples from the
Spartina
site, there were indications that there were bacterium-fungus interactions since populations of members of the α-subdivision of the
Proteobacteria
were negatively associated with AMF colonization and populations of members of the γ-subdivision of the
Proteobacteria
were positively associated with AMF colonization.
Identification of Different States of Hepatitis B Virus Infection with a Quantitative PCR Assay
Authors: Kessler Harald H. , Preininger Sabine , Stelzl Evelyn , Daghofer Elisabeth , Santner Brigitte I. , Marth Egon , Lackner Herwig , Stauber Rudolf E. 
Published: July 2002

ABSTRACT

The level of hepatitis B virus (HBV) DNA in serum reflects the replicative activity of HBV. To compare serum HBV DNA levels in different states of hepatitis B, 47 sera of patients with HBeAg-positive chronic hepatitis B, 4 sera of patients with HBeAg-negative chronic hepatitis B, 40 samples of patients after HBeAg seroconversion during alpha interferon treatment, 57 sera of inactive HBsAg carriers, and 42 sera of patients who had recovered from chronic hepatitis B more than 12 months prior to blood collection were checked for the presence of HBV DNA with the Amplicor HBV Monitor Test. In patients with HBeAg-positive chronic hepatitis B, the median of serum HBV DNA levels (8.3 × 10
8
copies/ml) was significantly higher than that for patients after HBeAg seroconversion (6.2 × 10
3
copies/ml) and than that for inactive HBsAg carriers (5.6 × 10
3
copies/ml). None of the patients who had recovered from hepatitis B had detectable HBV DNA in serum. Quantitative PCR proved to be a valuable tool for identification of different states of HBV infection. This technique was found to be a good method for determination of serum HBV DNA levels both for patients with HBeAg seroconversion and for inactive carriers who showed low viremia not detectable by conventional hybridization assays.
Evaluation of Human FcγRIIA (CD32) and FcγRIIIB (CD16) Polymorphisms in Caucasians and African-Americans Using Salivary DNA
Authors: van Schie Rob C. A. A. , Wilson Mark E. 
Published: July 2002

ABSTRACTTwo classes of low-affinity receptors for the Fc region of immunoglobulin G (IgG) (FcγR) are constitutively expressed on resting human neutrophils. These receptors, termed FcγRIIa (CD32) and FcγRIIIb (CD16), display biallelic polymorphisms which have functional consequences with respect to binding and/or ingestion of targets opsonized by human IgG subclass antibodies. The H131-R131 polymorphism of CD32 influences binding of human IgG2 and, to a lesser extent, human IgG3 to neutrophils. The neutrophil antigen (NA1-NA2) polymorphism of CD16 influences the efficiency of phagocytosis of bacteria opsonized by human IgG1 and IgG3. These polymorphisms may influence host susceptibility to certain infectious and/or autoimmune diseases, prompting interest in the development of facile methods for determination of CD32 and CD16 genotype in various clinical settings. We previously reported that genomic DNA from saliva is a suitable alternative to DNA from blood in PCR-based analyses of CD32 and CD16 polymorphisms. In the present study, we utilized for the first time this salivary DNA-based methodology to define CD32 and CD16 genotypes in 271 Caucasian and 118 African-American subjects and to investigate possible linkage disequilibrium between certain CD32 and CD16 genotypes in these two ethnic groups. H131 and R131 gene frequencies were 0.45 and 0.55, respectively, among Caucasians and 0.59 among African-Americans. NA1 and NA2 gene frequencies were 0.38 and 0.62 among Caucasians and 0.39 and 0.61 among African-Americans. Since FcγRIIa and FcγRIIIb synergize in triggering neutrophils, we also assessed the frequency of different CD32 and CD16 genotype combinations in these two groups. In both groups, the R/R131-NA2/NA2 genotype combination was more common than the H/H131-NA1/NA1 combination (threefold for Caucasians versus sevenfold for African-Americans). Whether individuals with the combined R/R131-NA2/NA2 genotype are at greater risk for development of infectious and/or autoimmune diseases requires further investigation, which can be conveniently performed using DNA from saliva rather than blood.
Shipment Impairs Lymphocyte Proliferative Responses to Microbial Antigens
Authors: Betensky Rebecca A. , Connick Elizabeth , Devers Jennifer , Landay Alan L. , Nokta Mostafa , Plaeger Susan , Rosenblatt Howard , Schmitz John L. , Valentine Fred , Wara Diane , Weinberg Adriana , M. Lederman Howard 
Published: July 2002

ABSTRACTLymphocyte proliferation assays (LPAs) are widely used to assess T-lymphocyte function of patients with human immunodeficiency virus infection and other primary and secondary immunodeficiency disorders. Since these assays require expertise not readily available at all clinical sites, specimens may be shipped to central labs for testing. We conducted a large multicenter study to evaluate the effects of shipping on assay performance and found significant loss of LPA activity. This may lead to erroneous results for individual subjects and introduce bias into multicenter trials.
Evaluation of Primary Binding Assays for Presumptive Serodiagnosis of Swine Brucellosis in Argentina
Authors: Paulo P. Silva , Vigliocco A. M. , Ramondino R. F. , Marticorena D. , Bissi E. , Briones G. , Gorchs C. , Gall D. , Nielsen K. 
Published: July 2002

ABSTRACT

An indirect enzyme-linked immunosorbent assay (IELISA), a competitive ELISA (CELISA), and a fluorescence polarization assay (FPA) for the presumptive serological diagnosis of swine brucellosis were evaluated using two populations of swine sera: sera from brucellosis-free Canadian herds and sera from Argentina selected based on positive reactions in the buffered antigen plate agglutination test (BPAT) and the 2-mercaptoethanol (2-ME) test. In addition, sera from adult swine from which
Brucella suis
was isolated at least once for each farm of origin were evaluated. The IELISA, CELISA, and FPA specificity values were 99.9, 99.5, and 98.3%, respectively, and the IELISA, CELISA, and FPA sensitivity values relative to the BPAT and the 2-ME test were 98.9, 96.6, and 93.8%, respectively. Actual sensitivity was assessed by using 37 sera from individual pigs from which
B. suis
was cultured, and the values obtained were as follows: BPAT, 86.5%; 2-ME test, 81.1%; IELISA, 86.5%; CELISA, 78.5%; and FPA, 80.0%.
Anti-Trypanosoma cruziImmunoglobulin G1 Can Be a Useful Tool for Diagnosis and Prognosis of Human Chagas' Disease
Authors: Cordeiro Flávia Drumond , Martins-Filho Olindo Assis , Da Costa Rocha Manoel Otávio , Adad Sheila Jorge , Corrêa-Oliveira Rodrigo , Romanha Alvaro José 
Published: July 2002

ABSTRACTTwo functionally distinct antibodies, categorized as conventional serology antibodies (CSA) and lytic antibodies (LA) have been described in Chagas' disease, based on their ability to bind to fixed epimastigotes (EPI) or live trypomastigotes (TRYPO), respectively. In this study, the profile of immunoglobulin G (IgG) subclasses of CSA and LA were analyzed by flow cytometry using serum samples from chronic chagasic patients with the indeterminate (IND), cardiac (CARD), and digestive (DIG) clinical forms of the disease. The results were expressed as percentage of positive fluorescent parasites (PPFP) for each sample. CSA showed a higher PPFP than LA for all samples. At serum dilutions between 1:256 and 1:2,048, IgG1 anti-EPI was able to distinguish chagasic from nonchagasic individuals. Different profiles of IgG subclasses were observed for CSA and LA. IgG1 and IgG2 were the main subclasses in CSA, whereas IgG1 and IgG3 were the predominant ones in LA. The reactivity of IgG2 anti-EPI was greater in IND and CARD than in DIG patients. Furthermore, a low level of IgG1 and IgG3 LA was associated with most of the CARD patients. On the other hand, a high level of IgG1 LA was associated with most of the IND patients. In summary, our findings indicate the potential of IgG1 anti-EPI for serological diagnosis of Chagas' disease, providing further evidence for a protective role of LA, and show that IgG1 anti-liveTrypanosoma cruziTRYPO may be used to predict the risk of cardiac damage in Chagas' disease.
Effects of Calorie Restriction on Polymicrobial Peritonitis Induced by Cecum Ligation and Puncture in Young C57BL/6 Mice
Authors: Sun Dongxu , Muthukumar Alagar Raju , Lawrence Richard A. , Fernandes Gabriel 
Published: July 2002

ABSTRACTCalorie restriction (CR) is known to prolong the life span and maintain an active immune function in aged mice, but it is still not known if rodents under CR can respond optimally to bacterial infection. We report here on the influence of CR on the response of peritoneal macrophages to lipopolysaccharide, splenic NF-κB and NF–interleukin-6 (IL-6) activities, and mortality in polymicrobial sepsis induced by cecal ligation and puncture (CLP). Macrophages from 6-month-old C57BL/6 mice on a calorie-restricted diet were less responsive to lipopolysaccharide, as evidenced by lower levels of IL-12 and IL-6 protein and mRNA expression. Furthermore, in vitro lipopolysaccharide-stimulated macrophages from mice under CR also expressed decreased lipopolysaccharide receptor CD14 levels as well as Toll-like receptor 2 (TLR2) and TLR4 mRNA levels. In addition, the phagocytic capacity and class II (I-Ab) expression of macrophages were also found to be significantly lower in mice under CR. Mice under CR died earlier (P< 0.005) after sepsis induced by CLP, which appeared to be a result of increased levels in serum of the proinflammatory cytokines tumor necrosis factor alpha and IL-6 and splenic NF-κB and NF–IL-6 activation 4 h after CLP. However, mice under CR survived significantly (P< 0.005) longer than mice fed ad libitum when injected with paraquat, a free radical-inducing agent. These data suggest that young mice under CR may be protected against oxidative stress but may have delayed maturation of macrophage function and increased susceptibility to bacterial infection.
Identification of thepsaAGene, Coding for Pneumococcal Surface Adhesin A, in Viridans Group Streptococci other thanStreptococcus pneumoniae
Authors: Jado Isabel , Fenoll Asunción , Casal Julio , Pérez Amalia 
Published: July 2002

ABSTRACTThe gene encoding the pneumococcal surface adhesin A (PsaA) protein has been identified in three different viridans group streptococcal species. Comparative studies of thepsaAgene identified in different pneumococcal isolates by sequencing PCR products showed a high degree of conservation among these strains. PsaA is encoded by an open reading frame of 930 bp. The analysis of this fragment inStreptococcus mitis, Streptococcus oralis, andStreptococcus anginosusstrains revealed a sequence identity of 95, 94, and 90%, respectively, to the corresponding open reading frame of the previously reportedStreptococcus pneumoniaeserotype 6B strain. Our results confirm thatpsaAis present and detectable in heterologous bacterial species. The possible implications of these results for the suitability and potential use of PsaA in the identification and diagnosis of pneumococcal diseases are discussed.
Toxin Genes and Other Characteristics of
Staphylococcus aureus
Isolates from Milk of Cows with Mastitis
Authors: Akineden Ö. , Annemüller C. , Hassan A. A. , Lämmler C. , Wolter W. , Zschöck M. 
Published: July 2002

ABSTRACT

In the present study, 103
Staphylococcus aureus
strains isolated from milk samples from 60 cows with mastitis from eight different farms in seven different locations in one region of Germany were compared pheno- and genotypically and by identification of various toxins. On the basis of culture and hemolytic properties and by determination of the tube coagulase reaction, all of the isolates could be identified as
S. aureus
. This could be confirmed by PCR amplification of species-specific parts of the gene encoding the 23S rRNA. In addition, all of the
S. aureus
isolates harbored the genes encoding staphylococcal coagulase and clumping factor and the genes encoding the X region and the immunoglobulin G binding region of protein A. These four genes displayed size polymorphisms. By PCR amplification, the genes for the toxins staphylococcal enterotoxin A (SEA), SEC, SED, SEG, SEI, SEJ, and TSST-1 but not those for SEB, SEE, SEH, and the exfoliative toxins ETA and ETB could be detected. To analyze the epidemiological relationships, the isolates were subjected to DNA fingerprinting by macrorestriction analysis of their chromosomal DNAs. According to the observed gene polymorphisms, the toxin patterns, and the information given by macrorestriction analysis of the isolates by pulsed-field gel electrophoresis, a limited number of clones seemed to be responsible for the cases of bovine mastitis on the various farms.
Use of Recombinant Envelope Proteins for Serological Diagnosis of Dengue Virus Infection in an Immunochromatographic Assay
Authors: Cuzzubbo Andrea J. , Endy Timothy P. , Nisalak Ananda , Kalayanarooj Siripen , Vaughn David W. , Ogata Steven A. , Clements David E. , Devine Peter L. 
Published: July 2002

ABSTRACT
An immunochromatographic test that incorporates recombinant antigens (Dengue Duo Rapid Strip Test; PanBio, Brisbane, Australia) has recently become commercially available. This assay is performed in 15 min and detects both immunoglobulin M (IgM) and IgG in a capture format. The four recombinant proteins used represent the N-terminal 80% of the viral envelope glycoproteins of dengue viruses 1, 2, 3, and 4, respectively. The sensitivity and specificity of the recombinant-antigen-based assay were 90 and 86%, respectively. The similar diagnostic performance of these antigens to that of enzyme-linked immunosorbent assays using whole dengue virus suggests that they mimic whole dengue viruses in primary structure and epitope conformation. These results suggest that recombinant proteins can be used in diagnostic assays for dengue to overcome safety issues associated with the use of whole virus.
Construction and Characterization of aMycobacterium tuberculosisMutant Lacking the Alternate Sigma Factor Gene,sigF
Authors: Chen Ping , Ruiz Rafael E. , Li Qing , Silver Richard F. , Bishai William R. 
Published: July 2002

ABSTRACTThe alternate RNA polymerase sigma factor gene,sigF, which is expressed in stationary phase and under stress conditions in vitro, has been deleted in the virulent CDC1551 strain ofMycobacterium tuberculosis. The growth rate of the ΔsigFmutant was identical to that of the isogenic wild-type strain in exponential phase, although in stationary phase the mutant achieved a higher density than the wild type. The mutant showed increased susceptibility to rifampin and rifapentine. Additionally, the ΔsigFmutant displayed diminished uptake of chenodeoxycholate, and this effect was reversed by complementation with a wild-typesigFgene. No differences in short-term intracellular growth between mutant and wild-type organisms within human monocytes were observed. Similarly, the organisms did not differ in their susceptibilities to lymphocyte-mediated inhibition of intracellular growth. However, mice infected with the ΔsigFmutant showed a median time to death of 246 days compared with 161 days for wild-type strain-infected animals (P< 0.001). These data indicate thatM. tuberculosis sigFis a nonessential alternate sigma factor both in axenic culture and for survival in macrophages in vitro. While the ΔsigFmutant produces a lethal infection of mice, it is less virulent than its wild-type counterpart by time-to-death analysis.
Transforming Growth Factor β1 Ameliorates Intestinal Epithelial Barrier Disruption byCryptosporidium parvumIn Vitro in the Absence of Mucosal T Lymphocytes
Authors: Roche James K. , Martins Clovis A. P. , Cosme Rosana , Fayer Ronald , Guerrant Richard L. 
Published: July 2002

ABSTRACTExposure to oocysts of the protozoanCryptosporidium parvumcauses intestinal epithelial cell dysfunction in vivo and in vitro, but effective means by which mucosal injury might be prevented remain unclear. We examined the ability of transforming growth factor β1 (TGF-β1)—a cytokine synthesized and released by cells in the intestine—to preserve the barrier function of human colonic epithelia when challenged withC. parvumoocysts and then studied the mechanisms involved. Epithelial barrier function was monitored electrophysiologically, receptors for TGF-β1 were localized by confocal microscopy, and TGF-β1-induced protein kinase C activation was detected intracellularly by translocation of its α isozyme. TGF-β1 alone enhanced intestinal epithelial barrier function, while exposure toC. parvumoocysts (≥105/monolayer) markedly reduced barrier function to ≤40% of that of the control. When epithelial monolayers were pretreated with TGF-β1 at 5.0 ng/ml, the barrier-disrupting effect ofC. parvumoocysts was almost completely abrogated for 96 h. Further investigation showed that (i) the RI and RII receptors for TGF-β1 were present on 55 and 65% of human epithelial cell line cells, respectively, over a 1-log-unit range of receptor protein expression, as shown by flow cytometry and confirmed by confocal microscopy; (ii) only basolateral and not apical TGF-β1 exposure of the polarized epithelial monolayer resulted in a protective effect; and (iii) TGF-β1 had no direct effect on the organism in reducing its tissue-disruptive effects. In exploring mechanisms to account for the barrier-preserving effects of TGF-β1 on epithelium, we found that the protein kinase C pathway was activated, as shown by translocation of its 80-kDa α isozyme within 30 s of epithelial exposure to TGF-β1; the permeability of epithelial monolayers to passage of macromolecules was reduced by 42% with TGF-β1, even in the face of active protozoal infection; and epithelial cell necrosis monitored by lactate dehydrogenase release was decreased by 50% 70 h after oocyst exposure. Changes in epithelial function, initiated through an established set of surface receptors, likely accounts for the remarkable barrier-sparing effect of nanogram-per-milliliter concentrations of TGF-β1 when human colonic epithelium is exposed to an important human pathogen,C. parvum.
Systemic and Mucosal Immune Responses in Mice after Mucosal Immunization with Group B Streptococcus Type III Capsular Polysaccharide-Cholera Toxin B Subunit Conjugate Vaccine
Authors: Shen Xuzhuang , Lagergård Teresa , Yang Yonghong , Lindblad Marianne , Fredriksson Margareta , Holmgren Jan 
Published: July 2002

ABSTRACT
Group B streptococci (GBS) colonize the female genital and rectal tracts and can cause invasive infection in susceptible newborns. An optimally effective GBS vaccine should induce mucosal and systemic immunity. In this study, we investigate the local and systemic immune responses to GBS type III capsular polysaccharide (CPS) after mucosal vaccination of mice via intranasal, peroral, rectal, and vaginal routes, with GBS type III CPS conjugated with recombinant cholera toxin B subunit (GBS III CPS-rCTB). Cholera toxin (CT) was added as an adjuvant. Immunoglobulin G (IgG) and IgA antibodies to the CPS were tested in serum, lungs, and intestinal, rectal, and vaginal extracts by enzyme-linked immunosorbent assay. The conjugated CPS administered by intranasal, peroral, rectal, and vaginal routes was much more effective at inducing both mucosal and systemic antibody responses to GBS III CPS than was unconjugated CPS. The CPS-specific immune responses in various organs were dependent on the route of immunization. Generally, the highest levels of IgA and IgG were generated in the regions or sites of the conjugate exposure. Thus, intranasal vaccination elicited the highest anti-CPS IgA and IgG antibody levels in the lungs, whereas peroral administration in the intestinal site and vaginal vaccination elicited the highest antibody levels in the vagina. Rectal vaccination was superior to the other routes in inducing high antibody levels in the rectum. The four routes of mucosal vaccination also induced distant antibody responses to CPS. Rectal vaccination induced high specific IgA levels in the vagina and intestine, and oral administration induced high specific IgA levels in the lungs and rectum. All four routes of vaccination with the conjugate elicited similarly high levels of anti-CPS IgG in serum. Intranasal vaccination with different doses of the conjugate (10, 30, and 80 μg of CPS) did not have a significant influence on the anti-CPS specific antibody responses. Intranasal immunization induced better antibody responses when one dose of the conjugate was divided and given on three consecutive days compared to administration of the full dose on one occasion. In conclusion, rectal and vaginal vaccination may be the best way of stimulating anti-CPS immune responses in the rectal and vaginal tracts, while high levels of anti-CPS antibodies in the lungs can be achieved after intranasal administration. The vaccination regimen thus might influence the mucosal immune response to CPS. This conjugate may serve as an effective mucosal vaccine for preventing mucosal colonization and invasive infection caused by GBS.