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At least 199 records · Page 11Linked to original sources
PubMed1977

Pathogenic mycoplasmas: cultivation and vertebrate pathogenicity of a new spiroplasma.

A spiroplasma recovered from allantoic fluids of chick embryos infected with the tick-derived suckling mouse cataract agent was grown in continuous passage on a new artificial culture medium. The cultured organisms induced typical ocular and other disease symptoms in susceptible animals, and were reisolated from involved host tissues. Although spiroplasmas have been previously recognized as plant and insect pathogens, this is the first spiroplasma shown to multiply at 37 degrees C and to be pathogenic for vertebrates.

Animals↗
PubMed1976

Activity of four cephalosporin antibiotics in vitro against bovine udder pathogens and pathogenic bacteria isolated from newborn calves.

The in vitro activity of chephaloridine, cephalexin, cefatrizine (BL-S640), and cephapirin (BL-P-1322) was evaluated by the serial dilution method against pathogenic gram-positive and gram-negative bacteria isolated from bovine udders and neonatal calf diseases. Cephapirin showed the comparatively greatest activity against the most common streptococcal species associated with bovine mastitis, whereas cephaloridine exhibited the best activity against Staphylococcus aureus. Cefatrizine was more active than the other cephalosporins against the gram-negative bacteria studied. In general, the minimal bactericidal concentration of each cephalosporin was two- to fourfold lower than the comparative value reported in the literature against the same type of pathogen of human origin.

Animals↗
PubMed1990

The 96-kilodalton antigen as an integral membrane protein in pathogenic Entamoeba histolytica: potential differences in pathogenic and nonpathogenic isolates.

A surface antigen (EH-96) of Entamoeba histolytica was demonstrated to be a plasma membrane antigen by immunoprecipitation of metabolically 35S-labeled antigen from live trophozoites, Triton X-114 detergent extracts, and plasma membrane-enriched fractions prepared by concanavalin A membrane stabilization and differential centrifugation. In addition, the antigen was localized to the plasma membrane by electron microscopy with colloidal gold. Antigen from E. histolytica strains immunoprecipitated with specific immunoglobulin M (IgM) or IgG2b monoclonal antibody was identical by one-dimensional peptide mapping with N-chlorosuccinimide. Additionally, antigen from different axenically cultivated amebae was demonstrated to be identical by N-chlorosuccinimide peptide mapping, as were peptide maps of IgG and IgM monoclonal antibody-purified antigen. The 96-kilodalton (kDa) surface antigen was identified on four axenically cultivated pathogenic isolates and on three polyxenically cultivated pathogenic isolates (zymodeme II) of E. histolytica but was absent or present in lesser quantity on six nonpathogenic polyxenically cultivated isolates. The 96-kDa antigen was detected in liver abscess fluid from four patients with amebic abscesses by enzyme-linked immunosorbent assay (ELISA) and immunoprecipitation. Two-dimensional gel electrophoresis profiles of the 96-kDa antigen purified from abscess material or from polyxenically cultivated trophozoites demonstrated that the antigens were related to the 96-kDa antigen found in axenically cultivated organisms.

Animals↗
PubMed1993

Repeats in an extracellular protein of weakly pathogenic strains of Streptococcus suis type 2 are absent in pathogenic strains.

Streptococcus suis type 2 strains that are pathogenic for pigs produce a 110-kDa extracellular protein factor (EF). Nonpathogenic and weakly pathogenic strains do not produce EF or produce a protein (EF*) that is immunologically related to EF. To study the pathogenesis of S. suis type 2 in pigs and to develop tools and methods for the control of S. suis type 2 infections, we cloned and characterized the genes encoding EF and various EF* proteins. Analysis of the deduced amino acid sequences showed that the first 833 amino acids at the N terminus of the EF and EF* proteins were nearly identical. The proteins differed, however, at their C termini. Unlike the 110-kDa EF protein, the EF* proteins contained several repeated units of 76 amino acids. The number and arrangement of the repeats in the EF* proteins varied. The data suggest that the gene encoding EF could have evolved from an epf* gene by a specific deletion event. The lack of repeated amino acid units in the EF protein may be related to virulence.

Amino Acid Sequence↗
PubMed2006

The pap operon of avian pathogenic Escherichia coli strain O1:K1 is located on a novel pathogenicity island.

We have identified a 56-kb pathogenicity island (PAI) in avian pathogenic Escherichia coli strain O1:K1 (APEC-O1). This PAI, termed PAI I(APEC-O1), is integrated adjacent to the 3' end of the pheV tRNA gene. It carries putative virulence genes of APEC (pap operon), other E. coli genes (tia and ireA), and a 1.5-kb region unique to APEC-O1. The kps gene cluster required for the biosynthesis of polysialic acid capsule was mapped to a location immediately downstream of this PAI.

Animals↗
PubMed2003

The high-pathogenicity island is absent in human pathogens of Salmonella enterica subspecies I but present in isolates of subspecies III and VI.

In this study we tested 74 Salmonella strains of all eight Salmonella groups and were able to demonstrate the presence of two high-pathogenicity island types in strains of Salmonella groups IIIa, IIIb, and VI. Most high-pathogenicity island-positive isolates produced yersiniabactin under iron-limited conditions and were positive for the high-molecular-weight proteins HMWP1 and HMWP2.

3' Flanking Region↗
PubMed1975

An experimentally pathogenic Bacillus species. II. The pathogenicity of the organism for mice.

The pathogenic effects produced in mice by intraperitoneal (i.p.) injection of a Bacillus species (OSU 372) are presented. This organism belongs to group 3 of the genus, and members of this group have not heretofore been shown to be pathogenic for mice even under experimental conditions. However, this organism is capable of producing a fatal involvement in doses which are not considered to be overwhelming. The mean lethal dose (LD50) of the organism for 20-25 g mice by the i.p. route is about 1 times 10-8 bacteria/mouse. A rapid drop in body temperature along with severe dehydration were noted in infected animals, and hematologic studies indicated that leukopenia and hemoconcentration also occurred. Although a transient septicemia developed, the bacteria could not be recovered from the tissues of fatally infected mice after a certain point in time. Results prevented indicate that the animals died of hypovolemic shock. A possible parallel with human bacillary infection is drawn.

Animals↗
PubMed2006

Distinct expression profiles of TGF-beta1 signaling mediators in pathogenic SIVmac and non-pathogenic SIVagm infections.

BACKGROUND: The generalized T-cell activation characterizing HIV-1 and SIVmac infections in humans and macaques (MACs) is not found in the non-pathogenic SIVagm infection in African green monkeys (AGMs). We have previously shown that TGF-beta1, Foxp3 and IL-10 are induced very early after SIVagm infection. In SIVmac-infected MACs, plasma TGF-beta1 induction persists during primary infection 1. We raised the hypothesis that MACs are unable to respond to TGF-beta1 and thus cannot resorb virus-driven inflammation. We therefore compared the very early expression dynamics of pro- and anti-inflammatory markers as well as of factors involved in the TGF-beta1 signaling pathway in SIV-infected AGMs and MACs. METHODS: Levels of transcripts encoding for pro- and anti-inflammatory markers (tnf-alpha, ifn-gamma, il-10, t-bet, gata-3) as well as for TGF-beta1 signaling mediators (smad3, smad4, smad7) were followed by real time PCR in a prospective study enrolling 6 AGMs and 6 MACs. RESULTS: During primary SIVmac infection, up-regulations of tnf-alpha, ifn-gamma and t-bet responses (days 1-16 p.i.) were stronger whereas il-10 response was delayed (4th week p.i.) compared to SIVagm infection. Up-regulation of smad7 (days 3-8 p.i.), a cellular mediator inhibiting the TGF-beta1 signaling cascade, characterized SIV-infected MACs. In AGMs, we found increases of gata-3 but not t-bet, a longer lasting up-regulation of smad4 (days 1-21 p.i), a mediator enhancing TGF-beta1 signaling, and no smad7 up-regulations. CONCLUSION: Our data suggest that the inability to resorb virus-driven inflammation and activation during the pathogenic HIV-1/SIVmac infections is associated with an unresponsiveness to TGF-beta1.

Animals↗
PubMed2004

PathoGene: a pathogen coding sequence discovery and analysis resource.

PathoGene is a web-based resource that streamlines the process of predicting genes in microorganisms and designs PCR primers for amplification to facilitate sequence analysis and experimentation. PathoGene currently supports primer design for every complete microbial, viral, and fungal genome as cataloged in GenBank by the National Center for Biotechnology Information (NCBI; http://www.ncbi.nlm.nih.gov/). The resulting primers can then be subjected to a stand-alone Basic Local Alignment Search Tool (BLAST) system called PathoBLAST in which the predicted PCR product and/or primers can be compared against the genome of interest or a similar genome to find related genes or estimate primer quality.

Bacillus anthracis↗
PubMed1979

[Studies of the incidence of healthy carriers of "pathogenic strains" or potentially pathogenic strains in the hospital environment].

An investigation has been carried out on healthy carriers of "positive Staphylococcus coagulase" and "occasional pathogenic" strains among kitchen, canteen and dispensary staff in the IVth Geriatric Division and First Aid Clinic of the Bologna "M. Malpighi" Hospital. All stains of "positive Staphylococcus coagulase" and "occasional pathogens" considered (Pseudomonas aeruginosa and Citrobacter) were put through antibiotic and chemotherapeutic sensitivity tests. The results are reported in detail.

Anti-Bacterial Agents↗
PubMed1987

Pathogenic and non-pathogenic Naegleria and Acanthamoeba spp.: a new autochthonous isolate from an Italian thermal area.

We performed an epidemiological survey of 17 thermal baths and the same number of mud-basins. This study aimed to ascertain the presence and incidence of small free-living amoebae, particularly species and/or strains of Naegleria and Acanthamoeba spp., occasional etiological agents of fatal meningoencephalitis and/or ocular infections in man. Over 51 samples of water and mud incubated at 37 degrees C and at 45 degrees C, 34 (66.7%) became positive at 37 degrees C and 33 (64.7%) at 45 degrees C. We isolated 7 (6%) strains of Naegleria spp., 6 (5.2%) of Acanthamoeba spp., 39 (33.6%) of Vahlkampfia spp., 28 (24.1%) of Hartmannella spp. and 36 (31.1%) strains of other species of free-living amoebae. 4 strains of Naegleria spp. and 6 of Acanthamoeba spp. proved pathogenic both in vivo, after experimental infection (meningoencephalitis) in the albino mouse, and in vitro, having previously contaminated monolayers of Vero cell line (cytopathic effect). Within the isolated pathogenic strains of Naegleria spp., a new strain of N. australiensis s.sp. italica was typified from an immunochemical point of view. This should be added to previous isolations reported by us.

Amoeba↗
PubMed1978

[Aggravation of experimental dysentery in mice and acceleration of the process of multiplication of pathogenic and conditionally pathogenic bacteria under the effect of yeast RNA].

Simultaneous infection of mice with Sh. flexneri subtype 2a, culture, with various doses of RNA sodium salt (NaRNA) or administration of the preparation 3 hours prior to or 6, 12, and 18 hours after the infection was accompanied by aggravation of the experimental infection in mice. This was expressed in a greater number of animals which contracted the disease and died, and in increased blood and peritoneal exudate microbiol density. The same processes were noted in mice infected with equal doses of shigella cultures passaged four times through broth with NaRNA, in comparison with the animals infected with shigellae passaged through broth alone. Incubation of a number of pathogenic and conditionally pathogenic microbes in broth with NaRNA was accompanied by a significant increase in the bacterial biomass volume; at the same time other conditionally patoogenic microbes or even different strains of the same type of the microbes reacted to NaRNA but weakly. A possibility of realization of all of these processes in vivo and their influence on the origination of bacterial complications and development of the infection is supposed.

Animals↗
PubMedDate not supplied

Isoenzyme patterns of pathogenic and non-pathogenic Naegleria spp. using agarose isoelectric focusing.

Using agarose isoelectric focusing, the isoenzyme patterns of 7 different enzymes were compared in 52 Naegleria strains. The pathogenic N. fowleri was found the most homogeneous species. N. lovaniensis seems to be constituted of different types which form nevertheless a cohesive group. Within N. gruberi, large interstrain band variations were found in almost all enzyme systems. A re-examination of the taxonomic position of this species may therefore be taken into consideration. High temperature strains from Australia were confirmed to be different from N. lovaniensis. Members of a new pathogenic Naegleria sp., N. australiensis, seem to occur in Europe. Large thermophilic strains with many large pores in the cysts show identical zymograms and may constitute a new species or genus.

Acid Phosphatase↗
PubMedDate not supplied

[Value of antigen, antibody and pathogen-specific lymphocyte detection in diagnosis of pathogen-induced arthritis].

In the differential diagnosis of infection-related arthritis (infectious arthritis, viral arthritis, reactive arthritis or Reiter's syndrome, Lyme disease) various laboratory methods are applied for the detection of the inciting antigen, specific antibodies or microbe-specific T-lymphocytes. In infectious (septic) bacterial or fungal arthritis, the definitive diagnosis can be made only by recovering the organism from the synovial fluid or membrane. Also, in reactive arthritis following extraarticular infection with Yersinia, Salmonella, Shigella, Campylobacter, or Chlamydia, one of the major shifts in perception of disease pathogenesis has been the detection of bacterial determinants by immunological methods and polymerase chain reaction (PCR) actually within the joint. In sexually acquired reactive arthritis, the etiologic diagnosis should be based on the direct detection of the pathogen (mainly C. trachomatis) from the urogenital smear specimen. For clinical routine, serological tests for bacteria specific antibodies (IgM and IgA class) are often necessary to show recent or persistent infection with the triggering pathogen. However, a cautionary note regarding the diagnostic significance of antibacterial antibody profiles has been sounded in several studies because of the high prevalence of bacteria-specific antibodies in the healthy population. The same problem may arise in the interpretation of virus-specific antibodies in the differential diagnosis of acute polyarthritis. Antigen-specific proliferation of synovial fluid lymphocytes can confirm the clinical diagnosis in patients with reactive arthritis and Lyme disease, although unspecific proliferation to several bacteria can also be observed in reactive arthritis as well as in many other arthritis.

Antibodies↗
PubMed1994

Studies on the bacterial flora of fish which are potential pathogens for human. Isolation of various potential human pathogenic organisms from different parts of fish and their significance in initiating human diseases.

Freshwater fish of different categories, collected from market of Dhaka City of Bangladesh, were studied for the bacterial flora. Potential human pathogens were isolated from about eighty-five percent of the fish studied. Organisms isolated were Aeromonas spp., (69.2%), Vibrio spp., (42.3%), Plesiomonas shigelloides (35.9%) and Escherichia coli (16.7%). The high association of potential human pathogens among the freshwater fish suggest that if fish are handled improperly or if consumed undercooked or uncooked may cause various diseases to susceptible individual.

Animals↗
PubMed1997

Ecto-nucleotide triphosphatase activity in pathogenic and non-pathogenic Entamoeba: protection from the cytotoxic effects of extracellular ATP.

The nucleotide triphosphatase (NTPase) activity of Entamoeba species and of Entamoeba histolytica strains, was compared. In all cases, with the exception of Entamoeba moshkovskii, the enzyme was activated by Ca2+ and not by Mg2+ and preferentially hydrolysed UTP with decreasing activity for ATP and GTP. The NTPase activity was associated with both the intracellular and the plasma membrane sulphonylbenzoyl-adenosine (FSBA) of trophozoites in which the ATP-site was facing externally, as shown by fluoroinhibition of NTPase activity and protection by the substrate added prior to FSBA. The highest surface activity was found in Entamoeba invadens and in the virulent E. histolytica HM1-A clone (HM1-IMSS passaged thrice through hamster liver). Significant lower activity was observed in non-pathogenic Entamoeba spp. The addition of ATP to cultures of pathogenic amoebae resulted in cell growth inhibition and lysis. This deleterious effect of adding ATP to the cultures was reversed by the addition of Ca2+. ATP hydrolysis by the amoeba may alter extracellular ATP-dependent processes in the host, which may be important for the survival of the amoeba in vivo.

Acid Anhydride Hydrolases↗
PubMed2004

EST and microarray analyses of pathogen-responsive genes in hot pepper (Capsicum annuum L.) non-host resistance against soybean pustule pathogen (Xanthomonas axonopodis pv. glycines).

Large-scale single-pass sequencing of cDNA libraries and microarray analysis have proven to be useful tools for discovering new genes and studying gene expression. As a first step in elucidating the defense mechanisms in hot pepper plants, a total of 8,525 expressed sequence tags (ESTs) were generated and analyzed in silico. The cDNA microarray analysis identified 613 hot pepper genes that were transcriptionally responsive to the non-host soybean pustule pathogen Xanthomonas axonopodis pv. glycines ( Xag). Several functional types of genes, including those involved in cell wall modification/biosynthesis, transport, signaling pathways and divergent defense reactions, were induced at the early stage of Xag infiltration. In contrast, genes encoding proteins that are involved in photosynthesis, carbohydrate metabolism and the synthesis of chloroplast biogenetic proteins were down-regulated at the late stage of Xag infiltration. These expression profiles share common features with the expression profiles elicited by other stresses, such as fungal challenge, wounding, cold, drought and high salinity. However, we also identified several novel transcription factors that may be specifically involved in the defense reaction of the hot pepper. We also found that the defense reaction of the hot pepper may involve the deactivation of gibberellin. Furthermore, many genes encoding proteins with unknown function were identified. Functional analysis of these genes may broaden our understanding of non-host resistance. This study is the first report of large-scale sequencing and non-host defense transcriptome analysis of the hot pepper plant species. (The sequence data in this paper have been submitted to the dbEST and GenBank database under the codes 10227604-10236595 and BM059564-BM068555, respectively. Additional information is available at http://plant.pdrc.re.kr/ks200201/pepper.html).

Capsicum↗