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C J Su

Publications and source records attributed to C J Su.

33 records · Page 2Linked to original sources
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

Prevention of postlaminectomy membrane: experimental and clinical observations.

An animal experimental study was performed to investigate the prevention of scar formation after laminectomy by applying Gelfoam, a free-fat graft and steroids as interposing material between the dura and muscles. There were 52 adult guinea pigs equally divided into four groups. They were sacrificed 2 weeks, 4 weeks and 12 weeks respectively after surgery. In the control group, there was young fibrous tissue at 2 weeks, which became more mature at 4 weeks. At 12 weeks, it became mature with varying thickness and canal extension. In the steroid group, it showed the same picture as the control group. In the Gelfoam group, there was foreign body reaction with disintegration of Gelfoam at 2 to 4 weeks. At 12 weeks, however in the free-fat graft group, viable fat graft could be seen at the laminectomy site with little fibrous tissue overlying the dura. In the clinical part, from September 1981 to September 1984, one of the authors (PQC) performed 100 laminectomies on patients with various causes of low back pain. A piece of free subcutaneous fat was laid on dura before wound closure. At follow-up, there was no adverse effect pertaining to its application. Most patients had considerable pain relief after the surgery. From the above observation, we believe that a free-fat graft is a simple and effective way to prevent postlaminectomy membrane. Steroids and Gelfoam do not have such advantage.

Adipose Tissue↗
PubMed1988

Identification of P1 gene domain containing epitope(s) mediating Mycoplasma pneumoniae cytoadherence.

A genomic library of Mycoplasma pneumoniae was constructed by cloning sheared genomic DNA into the expression vector lambda gt11. Recombinant clones were screened using anti-M. pneumoniae mAbs reactive with adhesin P1 epitopes that mediate cytadherence. 10 clones with different size inserts were isolated. These clones possessed P1 sequences localized to the COOH terminus of the P1 gene. All clones produced fusion proteins that reacted with acute and convalescent sera of patients infected with M. pneumoniae. Interestingly, one clone, P1-7, contained an epitope that was confined to a region of 13 amino acids present in the M. pneumoniae genome as a single copy. The identification of this cytadherence-related epitope permits the production of a synthetic peptide that can be used as a rational vaccine candidate and serodiagnostic probe.

Adhesins, Bacterial↗
PubMed1988

Regions of Mycoplasma pneumoniae cytadhesin P1 structural gene exist as multiple copies.

The Mycoplasma pneumoniae cytadhesin P1 structural gene with flanking regions was labeled by nick translation and used as a probe to analyze gene copy number in M. pneumoniae. Multiple bands of genomic DNA were hybridized by the probe. To establish what part of the P1 gene existed as multiple copies, the P1 gene and regions adjacent to the 3' and 5' ends were divided with restriction enzymes into 14 segments ranging in size from 174 to 651 base pairs. These pieces were purified on agarose gels, subcloned into pUC19, purified, labeled by nick translation, and used to probe the entire M. pneumoniae genome. Several regions near the middle and carboxy end of the P1 structural gene hybridized to single copies. The remaining P1 subclones hybridized to multiple bands under stringent hybridization conditions, indicating extensive homology with other parts of the M. pneumoniae genome. The single- versus multiple-copy nature of P1 structural gene domains is discussed.

Adhesins, Bacterial↗
PubMed1988

Structure and evolution of somatostatin genes.

A bovine pancreatic preprosomatostatin cDNA clone has been isolated and sequenced. Although it encodes a predicted 116 amino acid preprosomatostatin that is very similar in primary structure to those deduced from other mammalian preprosomatostatin cDNAs, there are some differences in amino acid composition. Hybridization of this clone to Northern blots of fetal bovine pancreatic poly(A+) RNA reveals a mRNA of 700 nucleotides. Evolution of the preprosomatostatin genes was studied by statistical analysis of anglerfish, catfish, bovine, rat, and human cDNA sequences. The results suggest that the two somatostatin genes present in both anglerfish and catfish were the result of a gene duplication event in a common ancestor of anglerfish and catfish.

Animals↗
PubMed1987

Cloning and sequence analysis of cytadhesin P1 gene from Mycoplasma pneumoniae.

Mycoplasma pneumoniae cytadhesin P1 was purified by monoclonal antibody affinity chromatography followed by preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The N-terminal 18-amino-acid sequence of P1 was determined and used to design two synthetic oligonucleotides, a 14-mer corresponding to amino acids 1 to 5 and an 18-mer corresponding to amino acids 7 to 12. These oligonucleotides served as hybridization probes for the identification of the P1 gene by Southern blot analysis of M. pneumoniae DNA. The P1 gene was cloned into plasmid pUC19 and mapped by using appropriate restriction endonucleases. The DNA sequence of the entire P1 gene was determined by subcloning appropriate DNA fragments into bacteriophage M13 and sequencing the DNA by the dideoxy-chain-termination method. The P1 gene contains an open reading frame of 4,881 nucleotides coding for a protein of 1,627 amino acids with a calculated molecular weight of 176,288. Properties of the amino-terminal sequence suggest that protein P1 may be synthesized as a precursor with subsequent processing to a mature protein of a calculated molecular weight of 169,758. Potential antigenic sites were determined by hydrophilicity plots. A computer search revealed that part of the predicted P1 sequence is homologous to cytoskeletal keratin of mammalian species and human fibrinogen alpha chain precursor. These results demonstrate the uniqueness of P1 as a cytadhesin and virulence determinant.

Amino Acid Sequence↗
PubMed1987

Protein synthesis during encystment of Azotobacter vinelandii.

Proteins synthesized during the encystment of Azotobacter vinelandii were radiolabeled with [35S]methionine and analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Pulse labeling was used to demonstrate that early encystment-specific proteins were beginning to be synthesized at 2 h and reached peak levels about 12 h after initiation of encystment. One such protein was identified as a beta-ketoacyl acyl-carrier protein synthase. The concentration of early proteins began to decrease at 16 h, when intermediate proteins specific to the differentiation process began to be synthesized. The cessation of synthesis of intermediate proteins began at 20 h postinitiation, and the labeling pattern of proteins then remained constant throughout the remaining 4 days of encystment.

3-Oxoacyl-(Acyl-Carrier-Protein) Synthase↗
PubMed1983

Immunoelectron microscopic study of somatostatin biosynthesis in dog pancreas.

The biosynthesis of somatostatin has been studied at the ultrastructural level in pancreatic islets by using rabbit antiserum against synthetic somatostatin. To document that the antiserum specifically bound preprosomatostatin, we have tested the ability of the antiserum to precipitate the product synthesized in vitro. Poly(A) enriched RNA isolated from catfish islets was translated in both the wheat germ extract and nuclease-treated reticulocyte lysate systems. It was found that the in vitro translation product, preprosomatostatin, could be recognized by the antibody against synthetic somatostatin. The morphological study was then performed by immunoelectron microscopy by using the Fab-peroxidase conjugate technique. In dog pancreatic islets, somatostatin immunoreactive reaction product was seen only in the delta cells. In these cells, they were detected on bound ribosomes, in the cisternae of the rough endoplasmic reticulum (ER) and Golgi apparatus, in the Golgi associated vesicles, and in secretory vesicles. These findings suggest that somatostatin precursor molecules are synthesized on bound ribosomes and discharged into the cisternae of the rough ER. They are then transported to the Golgi apparatus and transferred to the secretory vesicles for secretion. The different staining intensities in the secretory vesicles would suggest that the processing of the precursor molecules of somatostatin probably takes place in the secretory vesicles.

Animals↗
PubMed1983

Mammalian pancreatic preproglucagon contains three glucagon-related peptides.

We have isolated cDNA clones encoding bovine pancreatic preproglucagon. Twenty-five putative preproglucagon clones were selected by screening 3,100 clones of a fetal bovine pancreas cDNA library with a synthetic oligodeoxynucleotide probe. The probe was a mixture of synthetic 17-base DNA oligomers constructed to correspond to the six carboxyl-terminal amino acids (residues 24-29) of mature glucagon. Restriction mapping of six of these clones suggested that they represented a single mRNA species. Primary sequence analysis of one clone containing a 1,200-base-pair DNA insert revealed that it contained an essentially full-length copy of glucagon mRNA. Analysis of the cDNA suggested a protein coding sequence of 540 nucleotides and 5'- and 3'-untranslated regions of 90 and 471 nucleotides, respectively. This cDNA sequence encoded a 20-amino acid signal sequence followed by one for glicentin, a 69-amino acid polypeptide containing an internal glucagon moiety that has been found in porcine intestines. Glicentin is followed by two additional glucagon-like peptides, each flanked by paired basic amino acids (Lys, Arg) characteristic of prohormone processing. These polypeptide sequences show striking homology with those for glucagon and other members of the glucagon family of peptides.

Amino Acid Sequence↗
PubMed1981

Isolation and characterization of several unique lipids from Azotobacter vinelandii cysts.

Unique cyclic compounds were found in the lipid fraction of Azotobacter vinelandii cysts. In addition to two major molecular species which had already been identified, 5-n-alkylresorcinol and its galactoside derivative, five other molecular species (two alkyl side chain homologs of each) were isolated, and their structures were established by infrared, ultraviolet, nuclear magnetic resonance, and mass spectroscopy. These 10 compounds were 6-n-heneicosylresorcylic acid methyl ester and 6-n-tricosylresorcylic acid methyl ester, 5-n-(2-hydroxy)heneicosylresorcinol and 5-n-(2-hydroxy-tricosylresorcinol, 5-n-heneicosyl-4-acetylresorcinol and 5-n-tricosyl-4-acetylresorcinol, 6-n-heneicosyl-4-hydroxypyran-2-one and 6-n-tricosyl-4-hydroxypyran-2-one, and 6-(2-oxotricosyl)-4-hydroxy-pyran-2-one and 6-(2-oxopentacosyl)-4-hydroxypyran-2-one.

Azotobacter↗
PubMed1981

Unique lipids in Azotobacter vinelandii cysts: synthesis, distribution, and fate during germination.

Unique lipids found in Azotobacter vinelandii cysts are derived primarily from beta-hydroxybutyrate used to induce encystment. Tracer studies with beta-[14C]hydroxybutyrate showed that the biosynthesis of these compounds during encystment began at 8 to 12 h after induction and reached maximal levels after 2 days, Seventy percent of these unique lipids were found in the central body of the cysts, and 23% were found in the exine. Pyronic compounds, which are located mostly in the central body, were degraded during germination of the cysts, but little change occurred in the phenolic compounds, which are more uniformly distributed in the cysts.

Azotobacter↗