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Identification and isolation of mycoplasmas by immunobinding.

This laboratory has developed an immunobinding assay (IBA) to identify and detect mycoplasmas in a variety of specimens. The specimen is inoculated in volumes of 10 microliters onto nitrocellulose (NC) paper, which is then blocked, fixed, and incubated at room temperature. Specific antimycoplasma polyclonal or monoclonal antibody is first added, followed by peroxidase-labeled antibody directed toward the first immunoglobulin. Alternately, antimycoplasma IgG can be purified and conjugated to horseradish peroxidase for use in a direct assay. Addition of a developing solution results in the formation of purple color when mycoplasmas are present. Titers of rabbit antimycoplasma antisera range from 1:1,000 to 1:30,000. This assay can detect approximately 1 x 10(4) colony-forming units (CFU). This IBA has been used routinely to identify mycoplasmal isolates from 132 infected cell cultures. In addition, the procedure successfully detected Mycoplasma pneumoniae in throat swabs from patients with respiratory illness within 2 h. Perfect correlation was obtained with the IBA and microbiological culture of throat swabs for M. orale, M. salivarium and M. pneumoniae. The procedure was successfully used for other Mollicutes. It detected ureaplasmas in urogenital swabs and corn stunt spiroplasmas in infected corn plants and leafhoppers. A modification of the technique has been developed that identifies mycoplasma colonies on agar. It has also been used to assay for antimycoplasma antibodies in serum.

Animals↗

Characterization of some new insect-derived acholeplasmas.

Further analysis of three sterol-nonrequiring Mollicutes (strains PS-1, TAC, and YJS) isolated from gut fluids of insects confirms their similarity to Acholeplasma. They are serologically distinct from acholeplasmas of vertebrates and several other sterol nonrequiring Mollicutes isolated from plant surfaces. The PS-1 strain had a DNA G + C content of 31 mol % and a genome size of 1,030 megadaltons (MDa). Optimum temperature is in the range of 23 to 30 C. Thirty-two new nonhelical Mollicutes isolated from a much wider range of insect hosts were examined for acholeplasmas. Twenty-five of the insect isolates were grown consistently in serum-free broth, with or without Tween 80 supplements. Two of the acholeplasmas were serologically related to Acholeplasma florum, 13 strains were serologically identical to the TAC isolate reported earlier, and 10 of the putative acholeplasmas could not be identified with current reference antisera. Seven of the new nonhelical insect isolates appeared to be sterol-requiring Mollicutes. One sterol-requiring isolate (ELCN-1) was recovered from the hemolymph of a firefly, and is the first report of nonhelical Mollicutes in the insect hemocoel. Two of the seven sterol-requiring Mollicutes, which were nonhelical in earlier passages in broth, later reverted to typically helical spiroplasmas. Confirmation of sterol-requiring, nonhelical Mollicutes in insects would provide an important ecological finding that insects constitute an important reservoir for both acholeplasmas and mycoplasmas.

Acholeplasma↗

Exclusive occurrence of an extracellular protease capable of cleaving the hinge region of human immunoglobulin A1 in strains of Ureaplasma urealyticum.

The purpose of the study was to further investigate the occurrence of a specific immunoglobulin A1 (IgA1) protease among mycoplasmas of various origin. Fifty-two strains representing the genera Mycoplasma, Ureaplasma, Acholeplasma and Spiroplasma were examined. The ability to cause specific cleavage of human IgA1 in the hinge region resulting in intact Fab and Fc fragments was exclusively associated with strains of U. urealyticum. Thus, this trait may be used as a valuable differential characteristic of U. urealyticum. A more pronounced proteolytic activity capable of causing extensive degradation of both human and bovine IgA was demonstrated in the type strain of U. diversum.

Acholeplasma↗

Mycoplasmal ribosomal RNA genes and their use as probes for detection and identification of Mollicutes.

The number and organization of ribosomal RNA (rRNA) genes in the genome of Mycoplasma, Ureaplasma, Acholeplasma and Spiroplasma species were studied by the Southern hybridization technique. Restriction endonuclease-digested DNAs of the organisms were hybridized with nick-translated probes consisting of defined portions of the rrnB rRNA operon of Escherichia coli and with a recombinant plasmid pMC5 constructed of pBR325 and an insert containing M. capricolum genes for 23S, 5S and most of the 16S rRNA gene. The hybridization data indicate the presence of only one or two sets of rRNA genes in the mollicutes tested, a number lower than in eubacteria. The rRNA genes in mollicutes appear to be organized as clusters (acting apparently as operons) in the typical prokaryotic fashion, 5'-16S-23S-5S-3'. Despite the marked sequence homology shared by the rRNA operons of the different mollicutes and of E. coli, the operons are not identical. Thus, there is an EcoRI restriction site in the 16S rRNA genes in only 8 of the 13 species tested. The recombinant plasmid pMC5 has provided a sensitive probe for detection and identification of mollicutes in contaminated cell cultures. The purified DNA of the tested cell culture, or its supernatant fluid, was digested by EcoRI, and Southern blot hybridization of the products was performed with nick-translated pMC5. The probe did not hybridize with eukaryotic DNA. Each of the mollicutes species examinated exhibited a species-specific hybridization pattern. The hybridization tests enabled the identification of the four most prevalent mycoplasma contaminants of cell cultures, M. orale, M. hyorhinis, M. arginini and A. laidlawii. The test is capable of detecting 1 ng of mycoplasmal DNA, roughly equivalent to the DNA content of 10(5) mycoplasmas. The possibility of using this approach for detection and identification of noncultivable mycoplasmas in plant and insect tissues is under investigation.

Animals↗

Gliding mycoplasmas are inhibited by cytochalasin B and contain a polymerizable protein fraction.

Studies are presented on the effect of cytochalasin B (CB) on the growth of five Mycoplasma species, three Acholeplasma species, and one Spiroplasma species. The three gliding mycoplasma species (M gallisepticum, M pneumoniae and M pulmonis are the only mycoplasmas inhibited by CB. These are the only prokaryotes reported to be inhibited by CB. This suggested that these three mycoplasmas might have some sort of cytoskeletal structure. A protein fraction has been isolated from M gallisepticum which polymerizes in 0.6 M KCl and depolymerizes when KCl is removed. This fraction contains a major 58,000-dalton protein, a 46,000-dalton protein, and a minor 87,000-dalton protein.

Bacterial Proteins↗

Evaluation of the efficacy of zwitterionic dodecyl carboxybetaine surfactants for the extraction and the separation of mycoplasma membrane protein antigens.

The ability to extract mycoplasma membrane protein antigens using the alkyl carboxybetaine surfactants (N-dodecyl-N,N-dimethylammonio)butyrate (DDMAB, CMC = 4.3 mM) and (N-dodecyl-N,N-dimethylammonio)undecanoate (DDMAU, CMC = 0.13 mM) was assessed by protein titration and SDS-PAGE analysis. The maximum yields of membrane protein solubilization ranged from 20 to 90%, depending upon both the mycoplasma membrane investigated and the surfactant used. In five of six cases, the extraction was optimal for surfactant concentrations of ca. 25 mM. DDMAB displayed a higher efficiency in membrane protein extraction. The order of efficiency for both surfactants was Spiroplasma melliferum > Acholaplasma laidlawii > Mycoplasma gallisepticum. In contrast, DDMAU proved much more selective. The order of selectivity was M. gallisepticum > S. melliferum > A. laidlawii. The highest selectivity was recorded for the major proteins p67 and spiralin of M. gallisepticum and S. melliferum, respectively. For p67, notably, DDMAU proved superior to 10 other surfactants. Dot immunobinding and crossed immunoelectrophoresis analyses showed that both dodecyl carboxybetaines were suitable as membrane protein-solubilizing agents in immunological techniques. Furthermore, these surfactants did not exhibit effects adverse to the activity of A. laidlawii membrane NADH oxidase. One promising application of DDMAU is the separation of membrane proteins by ion-exchange HPLC as illustrated by the good resolution of M. gallisepticum membrane proteins and purification of p67 to almost homogeneity. These data show that dodecyl carboxybetaine surfactants are useful for the extraction of mycoplasma membrane antigens under mild conditions.(ABSTRACT TRUNCATED AT 250 WORDS)

Antigens, Bacterial↗

Sequence-specific methylation inhibits the activity of the Epstein-Barr virus LMP 1 and BCR2 enhancer-promoter regions.

We reported earlier that variable expression of the Epstein-Barr virus (EBV) encoded membrane protein LMP 1 in nasopharyngeal carcinoma and the host-cell-phenotype-dependent activity of the BCR2 promoter (one of the possible initiator sites for transcripts of Epstein-Barr nuclear antigens) in Burkitt's lymphoma (BL) lines can be related to the methylation status of the 5'-flanking regulatory regions of the BNLF 1 and BCR2 promoter, respectively. Here we report that clones of the BL line Mutu that differ in expression of LMP 1 also show a differential methylation pattern of the LMP 1 regulatory sequences: this region is hypomethylated in an LMP 1 expressing (group III) clone but methylated in a group I clone that does not express LMP 1. We introduced in vitro methylated reporter plasmids carrying BNLF 1 and BCR2 enhancer-promoter sequences into the BL line Raji and found that overall methylation of 5'-CG-3' sequences by the Spiroplasma methylase Sssl significantly reduced their activity compared to unmethylated or mock-methylated controls. Methylation of 5-CCGG-3' sequences by Hpall methyltransferase gave similar results. On the contrary, methylation of 5'GCGC-3' sequences by Hhall methyltransferase gave similar results. On the contrary, methylation of 5'-GCGC-3' sequences by Hpal methyltransferase resulted only in a moderate reduction of BNLF 1 enhancer-promoter activity. These data support the notion that methylation at discrete sites within control regions of latent, growth-transformation associated EBV genes may contribute to silencing their expression.

Burkitt Lymphoma↗

Comparative studies to determine the efficiency of 6 methylpurine deoxyriboside to detect cell culture mycoplasmas.

Studies were performed to compare three methods to detect mycoplasmal infection of cell cultures. The methods included microbiological assay by inoculation into broth and onto agar with anaerobic incubation, fluorescent DNA staining by Hoechst 33258, and mycoplasmal mediated cytotoxicity by 6 methylpurine deoxyriboside (6MPDR). Fluorescent DNA staining and 6MPDR assays were performed in an indicator cell culture system. A total of 2589 cell cultures were assayed. Mycoplasmas were detected in 174, an incidence of 6.7%. Species isolated were: Acholeplasma laidlawii, Mycoplasma orale, M. arginini, M. hyorhinis, M. fermentans, M. pirum, and M. pneumoniae. In separate studies, 6MPDR also detected infection with Spiroplasma mirum when this organism was deliberately inoculated into cell cultures. The efficiencies of microbiological testing, fluorescent DNA assays, and 6MPDR were 43.1, 98.8, and 97.1%, respectively.

Bisbenzimidazole↗

Sequencing of the intergenic 16S-23S rRNA spacer (ITS) region of Mollicutes species and their identification using microarray-based assay and DNA sequencing.

We have completed sequencing the 16S-23S rRNA intergenic transcribed spacer (ITS) region of most known Mycoplasma , Acholeplasma , Ureaplasma , Mesoplasma , and Spiroplasma species. Analysis of the sequence data revealed a significant interspecies variability and low intraspecies polymorphism of the ITS region among Mollicutes . This finding enabled the application of a combined polymerase chain reaction-microarray technology for identifying Mollicutes species. The microarray included individual species-specific oligonucleotide probes for characterizing human Mollicutes species and other species known to be common cell line contaminants. Evaluation of the microarray was conducted using multiple, previously characterized, Mollicutes species. The microarray analysis of the samples used demonstrated a highly specific assay, which is capable of rapid and accurate discrimination among Mollicutes species.

Animals↗

Synthesis and characterization of 6-O-(N-heptylcarbamoyl)-methyl-alpha-D-glucopyranoside, a new surfactant for membrane studies.

A new surfactant, 6-O-(N-heptylcarbamoyl)-methyl-alpha-D-glucopyranoside (HECAMEG, molar mass 335.38 g), was synthesized by a simple and low cost procedure from methyl-alpha-D-glucopyranoside. This surfactant is characterized by a high solubility in water (even at 0 degree C), ultraviolet light transparency in the region useful for protein detection, and a high critical micellar concentration (CMC = 19.5 mM), permitting fast elimination by dialysis. Furthermore, the surfactant is colorimetrically titratable by the anthrone technique and its weak interference in protein titration by the Lowry et al. procedure and the bicinchoninic method is easy to overcome. Two membrane proteins (NADH oxidase and succinate dehydrogenase) and a soluble enzyme (lactoperoxidase) retained full activity in the presence of HECAMEG below or above its CMC. The partial inhibition of beta-lactamase (soluble form) by HECAMEG above the CMC was probably only apparent and due to an interference of the surfactant with the substrate rather than a direct effect on the enzyme. HECAMEG was capable of extracting up to 75% of bacteriorhodopsin from the purple membrane of Halobacterium halobium in a nondenatured form as indicated by the spectral properties of the protein. It also solubilized spiralin from the Spiroplasma melliferum membrane with a great selectivity and efficiency, without detectable loss of antigenic properties. These data show that HECAMEG is a very mild surfactant, useful for membrane protein studies.

Bacteria↗

Search for eukaryotic motility proteins in spirochetes: immunological detection of a tektin-like protein in Spirochaeta halophila.

The serial endosymbiotic theory (SET) for the spirochete origin of undulipodia (cilia and eukaryotic flagella) predicts that a greater number of axonemal proteins will show homology to spirochete than to other bacterial proteins. To continue testing, the SET proteins associated with eukaryotic motility (tektin, centrin and calmodulin) were sought in Spirochaeta halophila. Western blot immunological detection techniques (for tektin and centrin) and two-dimensional gel analysis (for calmodulin) were used. Tektins are filamentous proteins extending the length of the axoneme in sperm tails and other undulipodia. Whole cell extracts of S. halophila were probed with antibodies made against three sea urchin (Lytechinus pictus) sperm axonemal tektins (tektins A, B, and C). In the spirochetes, one tektin-like protein was detected as a band on Western blots (a C tektin.) An antibody made against Lytechinus pictus sperm tail axonemes, affinity-purified against the C tektin of another sea urchin, Stronglyocentrotus purpuratus, bound to a 30 kDa protein from Spirochaeta halophila. The C tektin epitope was not detected in Escherichia coli. Both the poly- and monoclonal anti-centrin antibodies cross-reacted with multiple proteins in the control alga (Tetraselmis striata) and in the putatively negative control bacterium E. coli. No cross reaction was seen between any anti-centrin antibody and S. halophila. Neither did a two-dimensional gel analysis reveal the presence of calmodulin in these spirochetes or in the two other prokaryotes tested (Spiroplasma citri, Acholeplasma laidlawii). Although neither centrin nor calmodulin were detected, a 30 kDa tektin-like protein apparently is present in these spirochetes.

Biological Evolution↗

Effect of CpG methylation on gene expression in transfected plant protoplasts.

Activity of the cat gene driven by the cauliflower mosaic virus 35S promoter has been assayed by transfecting petunia protoplasts with the pUC8CaMVCAT plasmid. In vitro methylation of this plasmid with M.HpaII (methylates C in CCGG sites) and M.HhaI (methylates GCGC sites) did not affect bacterial chloramphenicol acetyltransferase (CAT) activity. It should be noted, however, that no HpaII or HhaI sites are present in the promoter sequence. In contrast, in vitro methylation of the plasmid with the spiroplasma methylase M.SssI, which methylates all CpG sites, resulted in complete inhibition of CAT activity. The promoter sequence contains 16 CpG sites and 13 CpNpG sites that are known to be methylation sites in plant DNA. In the light of this fact, and considering the results of the experiments presented here, we conclude that methylation at all CpG sites leaving CpNpG sites unmethylated is sufficient to block gene activity in a plant cell. Methylation of CpNpG sites in plant cells may, therefore, play a role other than gene silencing.

Blotting, Southern↗

Identification and characterization of the insertion element IS1070 from Leuconostoc lactis NZ6009.

A novel insertion sequence, designated IS1070, was identified on the lactose plasmid of Leuconostoc lactis NZ6009 by nucleotide sequence analysis. The 1027-bp sequence contains partially matched (24 of 28 bp) inverted repeats and has one long open reading frame. The deduced 305-amino-acid sequence demonstrated homology to transposases of IS30 from Escherichia coli, IS4351 from Bacteroides fragilis, IS1086 from Alcaligenes eutrophus, IS1161 from Streptococcus salivarius, ISAS2 from Aeromonas salmonicida and a putative protein encoded by ORF3 of virus SpV1-R8A2 B from Spiroplasma citri. At least fifteen IS1070-like sequences were detected in the genome of the parent Lc. lactis strain and five of these were situated on plasmids. Analysis of the direct repeats of two of these copies with that of IS1070 revealed differences in the target duplication lengths.

Amino Acid Sequence↗

Correlation of mollicutes and their viruses with multiple sclerosis and other demyelinating diseases.

To identify infectious diseases likely involved in MS, the author previously correlated the geographical distribution of MS with the global distribution of tick-borne diseases. Tick-borne infectious agents include mollicutes or mycoplasmas. The current paper reviews evidence that mollicutes, especially spiroplasmas, or their viruses could be the initial exposure that causes MS. Mollicute infections, including the effects of their toxins, can be treated or prevented with gold salts or tetracyclines. If further research recommended by this review finds a role of mycoplasmas in MS, treatment of MS with gold with tetracycline should be evaluated.

Animals↗

Sequences and antimycoplasmic properties of longibrachins LGB II and LGB III, two novel 20-residue peptaibols from Trichoderma longibrachiatum.

Longibrachins are members of the class of natural Aib-containing peptides designated as peptaibols. Six longibrachins, LGA I-IV and LGB II and III, were purified from a Trichoderma longibrachiatum strain by a procedure employing several chromatography steps including reversed-phase HPLC. The amino acid sequence determination was based on a combination of liquid secondary ion mass spectrometry (LSIMS) and two-dimensional 1H and 13C NMR spectroscopy. Longibrachins are 20-residue peptaibols with a C-terminal phenylalaninol and either neutral (LGA; Gln18) or acidic (LGB; Glu18) character. Longibrachins LGB II and III have novel sequences. Both longibrachins LGA and LGB show significant bactericidal activity against mycoplasmas (Acholeplasma, Mycoplasma, and Spiroplasma), with minimal inhibitory concentrations in the range 1.56-12.5 microM (3-25 micrograms/mL), and also perturb the permeability of membrane bilayers. Longibrachin LGA IV is the most potent of the presently known 18-20-residue peptaibols. The antimicrobial and membrane-perturbing properties of longibrachins, which are described here for the first time, were shown to be correlated.

Amino Acid Sequence↗

Isolation, molecular characterisation and genome sequence of a bacteriophage (Chp3) from Chlamydophila pecorum.

Chlamydiae are obligate intracellular pathogens that have a unique developmental cycle. Thirty nine viable isolates representing all nine currently recognised chlamydial species were screened by immunofluorescence with a cross-reacting chlamydiaphage monoclonal antibody. A novel chlamydiaphage (Chp3) was detected in C. pecorum, a chlamydial species not previously known to carry bacteriophages. Chp3 belongs to the Microviridae, members of this virus family are characterised by circular, single-stranded DNA genomes and small T = 1 icosahedral capsids. Double-stranded replicative form Chp3 DNA was purified from elementary bodies and used as a template to determine the complete genome sequence. The genome of Chp3 is 4,554 base pairs and encodes eight open reading frames organised in the same genome structure as other chlamydiaphages. An unrooted phylogenetic tree was constructed based on the major coat proteins of 11 members of the Microviridae and Chp3. This showed that the Microviridae are clearly divided into two discrete sub-families; those that infect the Enterobacteriaceae e.g. ØX174 and the bacteriophages that infect obligate intracellular bacteria or mollicutes including SpV4 (Spiroplasma melliferum), ØMH2K (Bdellovibrio bacteriovorus) and the chlamydiaphages. Comparative analyses demonstrate that the chlamydiaphages can be further subdivided into two groupings, one represented by Chp2/Chp3 and the other by ØCPG1/ØCPAR39.

Base Sequence↗

Late male-killing phenomenon found in a Japanese population of the oriental tea tortrix, Homona magnanima (Lepidoptera: Tortricidae).

A female-biased sex ratio was found in the oriental tea tortrix, Homona magnanima (Lepidoptera: Tortricidae), in Tsukuba, Ibaraki, Japan. There was no difference in mean egg hatch between the all-female and normal strains. Greater than 50% mortality was observed in the all-female strain larvae, suggesting that female-only broods are produced as a result of late male-killing. The female-biased sex ratio was maternally inherited and maintained, even when females were backcrossed with males of the normal strain, thus implicating cytoplasmic parasitism as its cause. The phenomenon was persistent in the presence of antibiotics, and was not due to infection by agents that cause other male-killing phenomena, such as Rickettsia, Wolbachia, Spiroplasma, or protozoan parasites. When a homogenate of dead male larvae of the all-female strain was inoculated in normal-strain larvae, this male-killing trait was transmitted to the next generation; thus, its causative agent is probably transmitted horizontally as well.

Animals↗

Broad-range PCR-TTGE for the first-line detection of bacterial pathogen DNA in ticks.

Ticks are known or suspected vectors for a wide range of bacterial pathogens. One of the first steps for tick-borne risk assessment is the detection of these pathogens in their vectors. In the present study, a broad-range PCR amplification of the eubacterial gene encoding the 16S rRNA gene combined with Temporal Temperature Gradient gel Electrophoresis (TTGE) was evaluated as a method allowing the one-step detection of bacterial pathogen DNA in ticks. Firstly, DNA extracts from bacteria known to be tick-borne pathogens, i.e., Borrelia burgdorferi lato sensu, Anaplasma phagocytophilum, Spotted Fever Group (SFG) Rickettsia spp., were used to establish a TTGE pathogen DNA reference marker. Secondly, we used broad-range PCR-TTGE to detect the presence of DNA from these three pathogens in 55 DNA extracts from pools of 10 nymphal Ixodes ricinus ticks, which have been previously shown to carry DNA from at least one of those bacteria by specific PCR. Among the 20 B. burgdorferi specific-PCR samples, 15 (75%) were also found to be positive using PCR-TTGE. Sixteen of the seventeen (94%) Rickettsia spp. PCR-specific samples were positive using PCR-TTGE detection and all PCR-specific positive extracts (11/11, 100%) for A. phagocytophilum were also positive using PCR-TTGE. Moreover, we identified unexpected bacterial sequences that were not related to any of the three pathogens such as a sequence related to Spiroplasma sp. Thus, broad-range PCR-TTGE allowed the single step detection of DNA from up to 3 pathogens in the same co-infected samples as well as detection of DNA from unexpected bacteria.

Anaplasma phagocytophilum↗