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Query: UMLS:C0026936 (Mycoplasma)
 14,761 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The ultrastructure of agar-grown Acholeplasma laidlawii incubated with specific antiserum or IgM fractions of this antiserum has been investigated by the thin-sectioning technique. Antiserum treatment resulted in the development of giant cells along the colony circumferences and in the coating of normal-size mycoplasmas with a periodically arranged extramembranous layer, consisting of attached immunoglobulins as shown by indirect immunoferritin labelling. The regular structure of the coat was not influenced by changes in temperature or by fixation of the membrane antigens prior to reaction with antibody. Extracellular enveloped viruses were uniformly covered with antibody in these experiments. IgM fractions of antiserum in high concentrations produced a similarly uniform extramembranous layer both on mycoplasmas and viruses. Possible explanations of the difference demonstrated between the regular arrangement of antigenic determinants on A. laidlawii membranes and the previously observed uniform binding of immunoglobulins to Mycoplasma gallisepticum are discussed.
J Gen Microbiol 1980 Feb
PMID:Ultrastructural study of the interaction between Acholeplasma laidlawii and antibody. 737 82

Aminopeptidase activity was demonstrated in extracts of Acholeplasma laidlawii, Mycoplasma bovirhinis, M. bovis and M. dispar. The enzyme specificity, which differed amongst the mycoplasma species examined, was characterized using 19 aminoacyl-beta-naphthylamides as substrates. The differences were detected after 4 h incubation with the substrates and potentially could be employed to aid in the characterization of certain mycoplasma species.
J Gen Microbiol 1980 Jul
PMID:Aminopeptidase activity of Acholeplasma laidlawii, Mycoplasma bovirhinis, Mycoplasma dispar and Mycoplasma bovis. 741 Nov 15

The DNA sequence of the gene encoding the early and specific immunogenic protein P36 of Mycoplasma hyopneumoniae has been determined. Comparison of the DNA sequence and the deduced amino acid sequence of P36 with known genes and proteins in data banks indicated that P36 is a L-lactate dehydrogenase (LDH) (EC 1.1.1.27). Biochemical analysis of protein P36 expressed from the cloned gene in Escherichia coli confirmed that P36 has L-lactate dehydrogenase activity. Protein P36 of M. hyopneumoniae therefore is termed LDH and its gene ldh. M. hyopneumoniae LDH was shown to contain the typical domains of LDH of other bacterial species. Immunologically however, we have shown that polyclonal antibodies against M. hyopneumoniae LDH do not cross-react with related LDH and show high specificity for M. hyopneumoniae. The ldh gene is preceded by several typical -10 sequences found in promoters of prokaryotes, but lacks the -35 sequence. Sequences rich in A+T, however, precede the -10 boxes, suggesting that factors involved in transcription initiation and their regulation may be different in M. hyopneumoniae compared to other bacterial species, but the putative ribosome binding site seems to be conserved.
J Gen Microbiol 1993 Feb
PMID:DNA sequence determination and biochemical analysis of the immunogenic protein P36, the lactate dehydrogenase (LDH) of Mycoplasma hyopneumoniae. 767 20

The authors studied nursing home residents serologically to determine whether atypical organisms were causes of radiologic pneumonia. The study was conducted at the Wisconsin Veterans Home, a facility with on-site microbiology and x-ray. Over one year, serologic examinations for Legionella, Mycoplasma, and Chlamydia were conducted for the residents who had pneumonia. Cultures and mortality were reviewed. Fifty-six episodes were studied (mean resident age 78 years). There was no fourfold titer change. Seventeen quality sputum specimens revealed Streptococcus pneumoniae (5), normal flora (4), Hemophilus influenzae (4), Moraxella catarrhalis (3), Staphylococcus aureus (1), and beta-hemolytic Streptococcus, not group A (1). The two-month mortality was 21%. This study did not result in serologic confirmation of atypical organisms' causing pneumonia. Antibiotic choice should be based on coverage of prevalent organisms, including Hemophilus influenzae, Moraxella, and Staphylococcus, as well as clinical features.
J Gen Intern Med 1994 Nov
PMID:Pneumonia in a nursing home. 785 75

PCR primers corresponding to the adhesin genes of Mycoplasma pneumoniae and Mycoplasma genitalium were shown to detect the corresponding organisms specifically. Absence of cross-reaction with seven other mollicute species and six unrelated bacterial species commonly found in humans was demonstrated. Positive control primers directed against human mitochondrial DNA could be mixed with the Mycoplasma primers without loss of specificity or sensitivity. A detection level of 10 c.f.u. of either Mycoplasma species could be readily obtained, even in the presence of 10(4) human cells. The triplex PCR method developed is very simple and does not require hybridization or the use of radioisotopes and allows detection and differentiation of these mycoplasmas against the background of human DNA found in clinical specimens.
J Gen Microbiol 1993 Oct
PMID:Use of a triplex polymerase chain reaction for the detection and differentiation of Mycoplasma pneumoniae and Mycoplasma genitalium in the presence of human DNA. 825 13

Test systems for rapid detection of mycoplasmas in biological samples have been elaborated on the base of the polymerase chain reaction (PCR). Amplification of the conservative rDNA sequences was used for testing of cell cultures for mycoplasmal contamination. Mycoplasma pneumoniae detection system has been developed based on amplification of the species-specific DNA sequences. Inversions of some repeated sequences in the Mycoplasma pneumoniae genome make it possible to run the PCR with a single primer. The revealed spacer length polymorphism for 16S-23S rDNA operons can be used in the mycoplasmas identification.
Mol Gen Mikrobiol Virusol
PMID:[Diagnosis of mycoplasma infections using directed amplification]. 851 51

Mycoplasma pneumoniae is the causative agent of primary atypical pneumoniae, and two distinct groups (I and II) have been established. Serological tests are relatively insensitive and the diagnosis by culture is time-consuming. This study was therefore undertaken to detect and to identify M. pneumoniae on culture media and in throat swab specimens by using polymerase chain reaction (PCR) and hybridization probes conjugated to alkaline phosphatase (Alp). Primer pairs were selected for amplification of DNA fragments in the C to D, F, G and I to J regions of the M. pneumoniae cytadhesin P1 genes. Amplified DNA fragments were visualized by staining with ethidium bromide after 2% agarose gel electrophoresis and by Southern hybridization with Alp-labeled probes. No amplification of the P1 genes was seen with any of five related Mycoplasma species, the others from M. pneumoniae. In all of 30 clinical isolates on PPLO medium, M. pneumoniae was detected with the F and G primer pairs, giving 100% of sensitivity. Of 69 throat swab specimens, 25 were positive with the F primer pairs, and 23 positive with the Gen Probe test. From these results, we conclude that the PCR with F or G primer pairs can be adapted as a practical method for the rapid diagnosis of M. pneumoniae infections.
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PMID:[Detection of Mycoplasma pneumoniae by using polymerase chain reaction and nonradioactive DNA probes]. 856 36

A new and rapid IgM enzyme immunoassay (EIA)(Immuno Well, Gen-Bio, San Diego, CA) was evaluated for its ability to accurately establish a serodiagnosis for acute Mycoplasma pneumoniae infection. Case definitions were established with the combination of complement fixation (CF) serology, IgM anti-P1 immunoblotting, and clinical and other laboratory data. In an asymptomatic population of 52 children and adults, the EIA was positive for 3.9%. For 17 serum pairs for which there was evidence of a greater than or equal to 4-fold rise in CF titer, 5 acute sera (29.4%) and 14 convalescent sera (82.3%) were positive. In applying the assay to sera that were acquired from a prospective study of childhood infection where the positive case definition was maintained for 22.3% of patients, the sensitivity, specificity, positive predictive value, and negative predictive value for the EIA was 90.5%, 93.2%, 79.2%, and 97.1%, respectively. When the EIA results of a "low-positive," as defined by the manufacturer, were excluded from the positive group, the respective values were 81.0%, 97.3%, 89.5%, and 94.7%. The accuracy of this new assay will be influenced by the prevalence of true illness in the populations to which it may be applied.
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PMID:An assessment of a new diagnostic indirect enzyme immunoassay for the detection of anti-Mycoplasma pneumoniae IgM. 860 46

Mycoplasma hominis and Acholeplasma laidlawii cultures resistant to antibacterial fluoroquinolone drugs ciprofloxacin (Cpf), ofloxacin (Ofl), and lomefloxacin (Lmf) were prepared by selection in liquid nutrient medium with ascending concentrations of Cpf. Resistant mycoplasma clones contained point mutations in the gyrase. A gene region determining quinolone resistance (QRDR gyrA): M. hominis contained C-->T transition resulting in substitution of Ser(83) for Leu and A. laidlawii G-->A resulting in substitution of Asp (91) for Asn. The phenomena of mutation formation during mycoplasma culturing in the presence of fluoroquinolones is studied. In the presence of Cpf in culture medium in concentrations of up to 10 micrograms/ml (for M. hominis) and 1 microgram/ml (for A. laidlawii) the mycoplasma populations contained cells with both altered and wild genotype. Culturing in the presence of higher Cpf concentrations resulted in elimination of cells nonmutant for QRDR gyrA. Besides in vitro studies, we analyzed clinical strains of M. hominis in the presence of different Cpf concentrations. M. hominis clones resistant to Cpf varying in genotypes were detected. These data permit a conclusion that the mechanism of fluoroquinolone resistance formation in mycoplasma includes several stages.
Mol Gen Mikrobiol Virusol 1998
PMID:[Formation of M. hominis and A. laidlawii resistance to fluoroquinolones]. 981 21

An accidental intra- and interspecies transmission of scrapie occurred in Italy in 1997 and 1998 following exposure to a vaccine against Mycoplasma agalactiae. PrP(Sc) in affected sheep and goats, collected from a single flock exposed to vaccination 2 years earlier, was molecularly typed. In five animals with iatrogenic scrapie, a PrP(Sc) type with a 20 kDa core fragment was found in all areas of the brain investigated. In three sheep and one goat, this isoform co-occurred with a fully glycosylated isoform that had a protease-resistant backbone of 17 kDa, whereas in two sheep and four goats, the two PrP(Sc) types were detected in different regions of the brain. In sheep with natural field scrapie, a PrP(Sc) type with physico-chemical properties indistinguishable from the 20 kDa isoform was found. The present results suggest the co-presence of two prion strains in mammary gland and brain homogenates used for vaccination.
J Gen Virol 2003 Apr
PMID:Molecular analysis of iatrogenic scrapie in Italy. 1265 8


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