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J B Baseman

Publications and source records attributed to J B Baseman.

At least 19 recordsLinked to original sources
PubMed1995

Molecular cloning and characterization of an adherence-related operon of Mycoplasma genitalium.

Adhesins and adhesin-related accessory proteins of pathogenic mycoplasmas are required for cytadherence and the subsequent development of disease pathology. The classic example has been Mycoplasma pneumoniae, which causes primary atypical pneumonia in humans. Mutants of M. pneumoniae defective in adhesins (P1 and P30) or in adherence-accessory proteins (HMW1 through HMW4) are unable to colonize host tissues and are avirulent. Mycoplasma genitalium, implicated in nongonococcal, nonchlamydial urethritis, pneumonia, arthritis, and AIDS progression, was found to encode a 140-kDa adhesin that shared both DNA and protein sequence similarities with P1, a major adhesin of M. pneumoniae. In this report, we show that M. genitalium possesses additional homolog sequences to well-characterized adherence-related genes and proteins of M. pneumoniae. The M. genitalium homologs are designated P32 and P69 and correspond to P30 and HMW3 of M. pneumoniae, respectively (J. B. Baseman, p. 243-259, in S. Rottem and I. Kahane, ed., Subcellular biochemistry, vol. 20. Mycoplasma cell membranes, 1993, and D. C. Krause, D. K. Leith, R. M. Wilson, and J. B. Baseman, Infect. Immun. 35:809-817, 1982). Interestingly, the operon-like organizations of P32 and P69 in the M. genitalium genome are similar to the organizations of P30 and HMW3 genes of M. pneumoniae, suggesting that the conservation of these adherence-related genes and proteins might have occurred through horizontal gene transfer events originating from an ancestral gene family.

Adhesins, Bacterial↗
PubMed1995

Mycoplasma pneumoniae and Mycoplasma genitalium mixture in synovial fluid isolate.

A mycoplasma cultured from synovial fluid specimens from a patient with pneumonia and subsequent polyarthritis was identified initially as Mycoplasma pneumoniae. In retrospective studies, the culture was shown also to contain Mycoplasma genitalium. In this paper, the laboratory techniques employed in the identification and separation of the two species are presented, and evidence to implicate postinfectious autoimmunity is provided. An increasing number of reports of M. genitalium in human tissue sites and difficulties in isolation and identification of the organism in the clinical laboratory suggest the need for more extensive application of rapid and specific detection systems for both M. genitalium and M. pneumoniae in the clinical laboratory.

Animals↗
PubMed1994

Identification of lactoferrin-binding proteins from Treponema pallidum subspecies pallidum and Treponema denticola.

Lactoferrin-binding or -associated proteins were identified in Treponema pallidum subspecies pallidum and Treponema denticola by affinity column chromatography using human lactoferrin and detergent-solubilized, radiolabelled spirochaetes. Two discrete polypeptides of T. pallidum with masses of 45 and 40 kDa and a broad band from 29-34 kDa exhibited association with human apo- and partially ferrated lactoferrin. T. denticola produced two proteins that associated with a lactoferrin affinity matrix (50 and 35 kDa). T. pallidum and T. denticola did not associate with soluble, human transferrin in parallel experiments. Soluble human lactoferrin competed with all lactoferrin-associated proteins from T. pallidum and T. denticola in competitive-binding assays. However, the T. denticola proteins dissociated from a lactoferrin-affinity matrix in the presence of differing concentrations of unlabelled, soluble lactoferrin competitor. Treatment with phospholipase D altered migration of the diffuse 29-34 kDa band of T. pallidum suggesting that the polypeptide was lipid-modified. Each of the lactoferrin-binding proteins from T. pallidum and T. denticola reacted with pooled rabbit syphilitic antisera. The lactoferrin-binding proteins of T. pallidum reacted with human sera from patients at all stages of syphilis. In addition, a monoclonal antibody generated against the 45 kDa polypeptide of T. pallidum crossreacted with the 29-34 kDa protein.

Antibodies, Bacterial↗
PubMed1993

Expression in Spiroplasma citri of an epitope carried on the G fragment of the cytadhesin P1 gene from Mycoplasma pneumoniae.

We have previously described the use of the replicative form (RF) of Spiroplasma citri virus SpV1 as a vector for cloning and expressing foreign genes in S. citri, an organism which reads UGA as a tryptophan codon (C. Stamburski, J. Renaudin, and J.M. Bové, J. Bacteriol. 173:2225-2230, 1991). We now report cloning and expression in S. citri of the G fragment of cytadhesin P1 gene from Mycoplasma pneumoniae. The G fragment was inserted in the SpV1 RF downstream of a synthetic ribosome binding site and introduced into S. citri by electroporation. Northern (RNA) blot analyses showed that in S. citri, the G fragment was transcribed from an SpV1 RF promoter as a 1.2-kb mRNA. The translation product was detected by Western blotting (immunoblotting) with a rabbit antiserum raised against total proteins from M. pneumoniae (strain FH) and was proved to be P1 specific by using monoclonal antibodies specific for the G region of the P1 protein. The apparent molecular mass of the polypeptide (24.5 kDa) indicates that in S. citri, the G fragment was fully translated in spite of the seven UGA codons present in the reading frame.

Adhesins, Bacterial↗
PubMed1991

Mycoplasma.

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Antigens, Bacterial↗
PubMed1991

Adhesin gene of Mycoplasma genitalium exists as multiple copies.

The structural gene of the 140 kDa adhesin of Mycoplasma genitalium was used to probe M. genitalium genomic DNA for gene copy number. Since multiple banding patterns were observed, the 140 kDa structural gene was subdivided into 10 contiguous fragments in size from 165 to 657 base pairs in order to determine which parts of the adhesin gene existed as multiple copies. Each fragment was labeled by nick translation and used to probe the entire M. genitalium genomic DNA. Approximately half the gene was present in single copy while the remaining sequences were multiple copied. Both single and multiple copy regions were interspersed throughout the structural gene.

Adhesins, Bacterial↗
PubMed1991

Distinctions in DNA and protein profiles among clinical isolates of Mycoplasma pneumoniae.

Clinical isolates of Mycoplasma pneumoniae previously shown to exhibit significant sequence divergency in a major 170 kDa adhesin, designated P1, were further characterized using restriction enzyme fingerprinting of genomic DNA and two-dimensional gel electrophoresis of total proteins. Numerous differences in DNA restriction patterns and protein profiles were found, possibly reflecting various degrees of virulence and antigenic potential.

Bacterial Proteins↗
PubMed1990

Cross-hybridization between the cytadhesin genes of Mycoplasma pneumoniae and Mycoplasma genitalium and genomic DNA of Mycoplasma gallisepticum.

Immunological cross-reactivity was observed between the cytadhesin proteins of Mycoplasma pneumoniae and Mycoplasma genitalium and a 155 kDa protein of Mycoplasma gallisepticum. Furthermore, the cytadhesin genes of M. pneumoniae and M. genitalium were used to demonstrate homology with M. gallisepticum genomic DNA under low stringency conditions suggesting that a family of adhesin-related genes exists among these pathogenic mycoplasmas.

Adhesins, Bacterial↗
PubMed1990

Characterization of the gene for a 30-kilodalton adhesion-related protein of Mycoplasma pneumoniae.

A previously identified trypsin-resistant surface protein of Mycoplasma pneumoniae clusters at the tip organelle of virulent mycoplasmas and appears to be essential for cytadherence and virulence. Monoclonal antibodies generated against this protein were used to identify positive recombinant clones from M. pneumoniae genomic DNA libraries. The structural gene was sequenced and contained an open reading frame of 825 nucleotides that encoded a protein of 275 amino acids with a calculated molecular mass of 29,743 Da. This protein (P30) contained three types of repeat sequences at the carboxy end, each consisting of six amino acids. In addition, the protein was proline rich (20.7%) and exhibited significant amino acid homology with the P1 cytadhesin of M. pneumoniae and with several matrix-associated eucaryotic proteins.

Adhesins, Bacterial↗
PubMed1990

Restriction fragment length polymorphism in the cytadhesin P1 gene of human clinical isolates of Mycoplasma pneumoniae.

Genomic DNA obtained from Mycoplasma pneumoniae clinical isolates spanning a 30-year period was analyzed for the presence of polymorphism in their P1 cytadhesin genes. All clinical isolates expressed a 170-kilodalton P1 protein that reacted with anti-P1 monoclonal antibodies. However, Southern blot analysis of specific M. pneumoniae isolates with subclones of the P1 structural gene revealed the presence of restriction fragment length polymorphism, permitting the classification of their P1 genes into two distinct categories.

Adhesins, Bacterial↗
PubMed1990

Sequence divergency of the cytadhesin gene of Mycoplasma pneumoniae.

The Mycoplasma pneumoniae cytadhesin P1 genes from two groups of clinical isolates that display restriction fragment length polymorphisms were cloned and sequenced. Within each group the nucleotide sequences were identical, but two major differences were detected between the groups. These two stretches of sequence divergence were located in multiple-copy regions of the P1 gene and resulted in considerable amino acid changes.

Adhesins, Bacterial↗
PubMed1990

Genome size of Mycoplasma genitalium.

The genome size of Mycoplasma genitalium was determined by using restriction enzymes that infrequently cut its DNA. The calculated value of 577 to 590 kilobases is one-fourth smaller than the genome of Mycoplasma pneumoniae, which is considered among the smallest genomes of self-replicating organisms.

DNA, Bacterial↗
PubMed1990

Molecular distinctions among clinical isolates of Mycoplasma pneumoniae.

Restriction enzyme fingerprinting of genomic DNA and Southern blots probed with subclones of the Mycoplasma pneumoniae cytadhesin P1 gene were used to characterize clinical isolates of M. pneumoniae. On the basis of the examination of 29 individual M. pneumoniae isolates, two distinct groups were established. Group 1, which displayed a 12-kilobase band following DNA digestion with HindIII, consisted of strain M129-B16 and three others obtained in the state of Washington during the 1960s. The remaining M. pneumoniae strains belonged to group 2, which lacked the 12-kilobase band and included samples from the 1940s, 1970s, and 1980s. This category also included the only M. pneumoniae strain isolated from the synovial fluid of an arthritic patient.

Adhesins, Bacterial↗
PubMed1989

Homologous regions shared by adhesin genes of Mycoplasma pneumoniae and Mycoplasma genitalium.

A lambda gt11 library of Mycoplasma genitalium genomic DNA was generated, and clones were identified using a pool of monoclonal antibodies directed against different epitopes of the 140 kDa adhesin protein. Because the 140 kDa protein of M. genitalium and the 170 kDa P1 adhesin of M. pneumoniae share biological properties such as a tip-associated location, cytadherence function and immunologic crossreactivity, we performed Southern blot analysis using these cloned partial 140 kDa gene fragments and 14 subclones that span the P1 structural gene of M. pneumoniae. Homologous regions of the two genes were identified.

Adhesins, Bacterial↗
PubMed1989

Spontaneous mutation results in loss of the cytadhesin (P1) of Mycoplasma pneumoniae.

The cytadhesin (P1) structural gene of a spontaneous mutant of Mycoplasma pneumoniae which displayed a P1-negative phenotype was analyzed. An extra adenine was discovered in a stretch of normally seven adenines near the N-terminal region of the mutant P1 structural gene. The frameshift mutation resulted in the early termination of protein translation. Possible causes of the mutation are discussed.

Adhesins, Bacterial↗
PubMed1989

DNA and protein sequence homologies between the adhesins of Mycoplasma genitalium and Mycoplasma pneumoniae.

Mycoplasma genitalium and Mycoplasma pneumoniae are morphologically and serologically related pathogens that colonize the human host. Their successful parasitism appears to be dependent on the product, an adhesin protein, of a gene that is carried by each of these mycoplasmas. Here we describe the cloning and determine the sequence of the structural gene for the putative adhesin of M. genitalium and compare its sequence to the counterpart P1 gene of M. pneumoniae. Regions of homology that were consistent with the observed serological cross-reactivity between these adhesins were detected at both DNA and protein levels. However, the degree of homology between these two genes and their products was much higher than anticipated. Interestingly, the A + T content of the M. genitalium adhesin gene was calculated as 60.1%, which is substantially higher tham that of the P1 gene (46.5%). Comparisons of codon usage between the two organisms revealed that M. genitalium preferentially used A- and T-rich codons. A total of 65% of positions 3 and 56% of positions 1 in M. genitalium codons were either A or T, whereas M. pneumoniae utilized A or T for positions 3 and 1 at a frequency of 40 and 47%, respectively. The biased choice of the A- and T-rich codons in M. genitalium could also account for the preferential use of A- and T-rich codons in conservative amino acid substitutions found in the M. genitalium adhesin. These facts suggest that M. genitalium might have evolved independently of other human mycoplasma species, including M. pneumoniae.

Amino Acid Sequence↗
PubMed1989

Serum lipoprotein binding by Treponema pallidum: possible role for proteoglycans.

Acquisition by the syphilis spirochaete, Treponema pallidum, of radioiodinated total human plasma lipoprotein and lipoprotein subfractions was examined. Time dependent and saturation binding kinetics were observed for total lipoproteins and subfractions, including high density lipoproteins, low density lipoproteins (LDL), and very low density lipoproteins. All subfractions competed equally well in binding iodinated total lipoproteins and individual subfractions, but apoproteins common to all subfractions were ineffective in inhibiting lipoprotein acquisition. The interaction of LDL with T pallidum was studied further and, interestingly, the presence of 17% sulphated dextran sulphate (DS) in the reaction mixture containing treponemes and LDL resulted in up to 172 times more LDL being bound by live treponemes. Biological variability was observed in the extent of increased LDL bound in the presence of 17% sulphated DS by preparations of T pallidum isolated from different infected rabbits. Saturation kinetics of iodinated LDL acquisition was obtained in the presence of 17% sulphated DS but not 1% sulphated DS. Other proteoglycan molecules, such as chondroitin sulphate, hyaluronic acid and heparin, and fibronectin, the extracellular matrix protein targeted by treponemes in parasitism of host cells and tissues neither diminished nor enhanced LDL binding by live treponemes. Only 5% and 10% of associated radioactivity was released from treponemal surfaces after T pallidum was incubated with iodinated LDL and 17% sulphated-DS for 15 and 30 minutes, respectively. These data show binding and possible internalisation of host lipoproteins by T pallidum, which may be mediated by sulphated proteoglycan. Sulphated proteoglycans accumulate during T pallidum infections of host cells.

Dextran Sulfate↗