Search PubMed⌕ Search

Biomedical subjects

J C Hong

Publications and source records attributed to J C Hong.

33 records · Page 2Linked to original sources
PubMed1994

Isolation and characterization of three soybean extensin cDNAs.

We have characterized three different soybean (Glycine max) mRNAs that encode apoproteins of extensins, a family of cell wall hydroxyproline-rich glycoproteins (HRGPs). These transcripts encoded distinctive Tyr-rich proteins containing characteristic Ser-Pro4 sequences organized in higher-order repetitive units. The first transcript encoded an extensin SbHRGP-1 containing the 16-amino acid repeat Ser-Pro4-Ser-Pro-Ser-Pro4-Tyr-Val-Tyr-Lys, with Val occasionally replaced by Ile or Tyr. The second transcript encoded the SbHRGP-2 protein containing the 16-amino acid repeat Ser-Pro4-Ser-Pro-Ser-Pro4-Tyr-Tyr-Tyr-Lys/His. The third transcript encoded the SbHRGP-3 protein containing a variant of 9- or 10-amino acid canonical repeats: Ser-Pro4-Tyr-Lys-Tyr-Pro, Ser-Pro5-Tyr-Lys-Tyr-Pro, and Ser-Pro4-Val-Tyr-Lys-Tyr-Lys, respectively. The dramatic amino acid substitutions in the Tyr-rich blocks (Tyr-X-Tyr-Lys) among these HRGPs indicate that each SbHRGP may have a different function in cell wall architecture.

Amino Acid Sequence↗
PubMed1993

Identification of protein-binding DNA sequences in an auxin-regulated gene of soybean.

The promoter region of a soybean auxin-responsive gene, GmAux28, was analyzed to identify protein-binding DNA sequences that may be involved in regulation of expression. Using DNase I footprinting and gel mobility shift assays, multiple regions of interaction, including eight major protein-binding sites, were observed in the GmAux28 gene. Two sequence motifs, TGACGACA and TCCACGTGTC, related to as-1/Hex and G-box elements, respectively, found in several plant promoters, were identified. Four distinct A/T-rich domains were identified; such A/T-rich domains appear to modulate, but not to specify, the expression of many genes. Two new sequence motifs, delta-1 (D1) and delta-4 (D4) were also identified. D1 and D4 share a very similar core sequence, TAGTxxCTGT and TAGTxCTGT, respectively. In gel mobility shift analyses, D1 and D4 elements exhibit a complex interaction of binding proteins. The GmAux22 promoter also contains D1-related elements which compete with the GmAux28 elements. Sequence comparisons have identified D1/D4-like sequences in several other auxin-responsive genes suggesting the possible importance of D1/D4 and the respective binding proteins in the regulation of expression of these genes.

Base Sequence↗
PubMed1993

Production and characterization of monoclonal antibodies against alpha and beta spectrin subunits.

Twenty monoclonal antibodies against human erythrocyte spectrin were generated using purified native spectrin as the immunogen. Thirteen out of 20 monoclonal antibodies reacted to the alpha subunit, and the remaining seven monoclonal antibodies reacted to the beta subunit in Western blot analysis. One anti-beta subunit and two anti-alpha subunit monoclonal antibodies cross-reacted with the cell lysate of the non-erythroid T. lymphoma, J. Jhan, cell line. Identification of 20 monoclonal antibodies to the respective tryptic domains was also achieved. The specificity of these antibodies to respective tryptic domains of spectrin confirms the alignments and uniqueness of each of the previously identified five domains in the alpha subunit and four domains in the beta subunit, and establishes the identity of proteolytic daughter peptide fragments.

Animals↗
PubMed1993

Overproduction of indole acetic acid in Azospirillum lipoferum using the Escherichia coli trp operon.

A recombinant plasmid carrying the trp operon from Escherichia coli, which synthesizes tryptophan from chorismate, was constructed by using a broad host range plasmid vector pRK290; a mutant trp plasmid for tryptophan overproduction was then selected. The physiological, biochemical, and genetic properties of the Azospirillum lipoferum KY6, a potential nitrogen fixer of rice, harbouring the recombinant trp plasmid pMJC1 and its mutant pMJC101, were compared with those of the wild-type bacteria. Anthranilate synthetase is known to be the trpE gene product which plays a key role in the regulatory step in the feedback control of tryptophan biosynthesis. The enzyme activity of the Azospirillum lipoferum KY6 carrying pMJC1 or pMJC101 was respectively 7- and 30-fold higher than that of the wild type in the presence of 10(-4)M tryptophan. As expected, the amount of tryptophan biosynthesis in A. lipoferum KY6 (pMJC101) was increased approximately 100-fold as compared with the wild type, which led to overproduction of indole acetic acid even without addition of exogenous tryptophan. Moreover, the recombinant trp plasmid was fairly stable in A. lipoferum KY6 host, showing only 25% loss of the plasmid itself or the trp insert after 40 generations.

Azospirillum↗
PubMed1990

Characterization of a proline-rich cell wall protein gene family of soybean. A comparative analysis.

Further characterization of a proline-rich cell wall protein gene family from soybean (Glycine max (L.) Merr) has been accomplished by the isolation and sequence analysis of two additional genes, SbPRP2 and SbPRP3, which encode mRNAs of 1050 and 650 nucleotides in length, respectively. Like the proline-rich protein gene, SbPRP1, which was previously reported (Hong, J. C., Nagao, R. T., and Key, J. L. (1987) J. Biol. Chem. 262, 8367-8376), these two SbPRP genes encode proteins having a signal peptide sequence and repeats of Pro-Pro-Val-Tyr-Lys. The SbPRP2 gene encodes a protein of 26 kDa which contains a perfect alternating repeat of Pro-Pro-Val-Tyr-Lys and Pro-Pro-Val-Glu-Lys. The SbPRP3 encodes a 10-kDa protein which also contains Pro-Pro-Val-Tyr-Lys as a major amino acid repeat, but the overall amino acid sequence of this protein is more variable than that of SbPRP1 and SbPRP2. RNA blot analyses have demonstrated that there are marked differences in the pattern of expression of each SbPRP in various soybean tissues. In contrast, sequence analysis reveals that the SbPRP genes contain a high degree of sequence conservation. Nucleotide sequence homology extends 90 to 100 base pairs upstream of the transcription initiation site and includes typical CAT and TATA sequences. Approximately 80 base pairs of the 3'-noncoding sequence around the polyadenylation signal is also highly conserved. Therefore, the DNA sequence upstream of the 5'-conserved region is presumed to contain cis-elements accounting for the developmental and tissue specificity of gene expression. While the pentameric repeat structures occur in all SbPRP genes, the encoded proteins are predicted to be different in several features including basicity, substitutions of tyrosine and glutamic acid in the repeat, and the size of the mature protein.

Amino Acid Sequence↗
PubMed1989

Developmentally regulated expression of soybean proline-rich cell wall protein genes.

Previously, we reported the characterization of a developmentally regulated proline-rich cell wall protein (SbPRP1) gene of soybean; the encoded protein is represented by a consensus amino acid repeat structure of Pro-Pro-Val-Tyr-Lys [Hong, J.C., Nagao, R.T., and Key, J.L. (1987). J. Biol. Chem. 262, 8367-8376]. Two other closely related members of this family of proline-rich protein (PRP) genes (SbPRP2 and SbPRP3), which differ from the extensin family of cell wall proteins, have been characterized (J.C. Hong, R.T. Nagao, and J.L. Key, unpublished results). Here we report studies on the regulation of expression of this gene family during soybean development by analyzing various plant organs, including leaves, stems, and roots of etiolated seedlings and light-grown plants, as well as young and mature pods, seed coats, and cotyledons. These organs were tested at different stages of development (young and fully mature tissue). Although a high level of sequence homology is observed at the nucleotide and amino acid sequence level among these three PRP genes/proteins, there are marked differences in the patterns of expression of each gene in different plant organs and organ regions. SbPRP1 is highly expressed and is the predominant form of PRP transcript in the mature hypocotyl, root, and immature seed coat. SbPRP2 is the major form of PRP in the apical hypocotyl and young suspension culture cells. SbPRP3 is the major form of PRP gene expressed in aerial parts; it is highly expressed in leaves, although no expression is detected in the roots.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1989

Intraoperative antegrade colon irrigation--in the management of obstructing left-sided colon cancer.

The management of obstructing left-sided colon cancer remains controversial. The advent of intraoperative antegrade colonic irrigation (I.A.C.I.) has allowed primary anastomosis to be performed in the obstructed bowel. From July 1985 to Feb. 1989, there were eleven patients with obstructing left-sided colon cancer admitted to Changhwa Christian Hospital. Eight of these patients, five men and three women, age ranged from 31 to 80 years old, accepted the I.A.C.I. procedure and followed by the one-staged operations. The I.A.C.I. procedure was advocated by Dudley et al in 1980. Postoperatively, there was no case which suffered from clinical leakage or sepsis, except two cases with mild wound infection. Consequently, there was no operative mortality.

Adult↗
PubMed1989

Stercoraceous perforation of the colon.

Non-traumatic colon perforations are usually caused by malignancy, diverticulum and colitis. They rarely result from stool impaction. A 74-year-old woman with stercoracous perforation of the colon is reported. She had a long history of constipation and hypertension treated irregularly with cathartics, enemas, diuretics and beta-blockers. Resection of the perforated colon with a proximal diverting colostomy and Hartman's procedure was performed. The patient tolerated the operation and subsequent reanastomosis 6 weeks later. In the case of elderly patients with constipation, early management of the constipation is mandatory, although this condition of stercoraceous perforation is rare.

Aged↗
PubMed1987

Characterization and sequence analysis of a developmentally regulated putative cell wall protein gene isolated from soybean.

A cDNA clone, pTU04, which hybridizes to two different sizes of mRNA on Northern blots was isolated from soybean suspension culture cell poly(A) RNA. Northern analysis reveals that meristematic tissue produces a 1050-nucleotide mRNA while quiescent mature cells produce primarily a 1220-nucleotide mRNA homologous to pTU04. The cDNA and its corresponding genomic clone have been partially characterized. The nucleotide sequence of the gene predicts a proline-rich protein, designated SbPRP1, which contains a signal peptide sequence and 43 repeats of a sequence consisting primarily of Pro-Pro-Val-Tyr-Lys (CCA-CCA-GTT-TAC-AAG). From nuclease S1 and hybrid-select translation analyses, the cDNA clone pTU04 appears to represent the mRNA for the mature tissue 1220-nucleotide RNA observed on Northern blots. Although there is no direct proof that the encoded protein is a cell wall protein, it has the properties similar to previously isolated cell wall proteins: 1) it is very basic with a high content of Pro, Tyr, and Lys; 2) it has similar hydropathic properties; and 3) its repeating unit shares sequence homology with that of more highly characterized cell wall proteins, generally termed extensin (Chen, J., and Varner, J. E. (1985) EMBO J. 4, 2145-2151; Smith, J. J., Muldoon, E. P., Willard, J. J., and Lamport, D. T. A. (1986) Phytochemistry 25, 1021-1030.

Amino Acid Sequence↗
PubMed1986

Auxin-regulated gene expression.

During the 1960s a wide range of studies provided an information base that led to the suggestion that auxin-regulated cell processes--especially cell elongation--may be mediated by auxin-regulated gene expression. Indirect evidence from our work, based on the influence of inhibitors of RNA synthesis (e.g. actinomycin D) and of protein synthesis (e.g. cycloheximide) on auxin-induced cell elongation, coupled with correlations of the influence of auxin on RNA synthesis and cell elongation, provided the basis for this suggestion. With the availability of techniques for DNA-DNA and DNA-RNA hybridization, mRNA isolation-translation, in vitro 2D gel analysis of the translation products, and ultimately the cloning by recombinant DNA technologies of genomic DNA and copy DNAs (cDNAs) made to poly(A)+ mRNAs, we and others have provided direct evidence for the influence of auxin on the expression of a few genes (i.e. poly(A)+ RNA levels). Our laboratory has provided evidence for auxin's both down-regulating and up-regulating the level of a few poly(A)+ mRNAs out of a population of about 4 X 10(4) sequences that are not significantly affected by auxin. In our studies on auxin-regulated cell elongation, two cDNA clones (pJCW1 and pJCW2) were isolated which corresponded to poly(A)+ mRNAs that responded during growth transitions in a way consistent with a potential role of their protein products in cell elongation. These mRNAs are most abundant in the elongating zone of the soybean hypocotyl. Upon excision and incubation in the absence of auxin, these mRNAs deplete in concert with a decreasing rate of cell elongation. Addition of auxin to the medium results in both increased levels of these mRNAs and enhanced rates of cell elongation. These mRNAs do not deplete if auxin is added to the medium at the onset of excised incubation, and cell elongation rates remain high. We have isolated and sequenced genomic clones that are homologous to these cDNAs. Of the two genes sequenced, both genes are members of small multigene families. There are regions of high amino acid homology even though the nucleotide sequences are sufficiently different in these regions for cross-hybridization of the clones not to be observed. More recently others, especially Guilfoyle's laboratory, have shown that auxin selectively and rapidly influences the level of certain mRNAs and proteins. We have worked on other gene systems such as ribosomal proteins and possible cell wall proteins that are responsive to auxin; again the nature of regulation of expression of these genes is not known.(ABSTRACT TRUNCATED AT 400 WORDS)

DNA↗
PubMed1982

Antiarrhythmic and hemodynamic responses to adenosine triphosphate during infusion of epinephrine in dogs anesthetized with halothane.

The effects of adenosine triphosphate (ATP) on cardiovascular responses to epinephrine were evaluated in dogs anesthetized with halothane. The dose of epinephrine required to induce arrhythmias averaged 1.05 +/- 0.52 microgram/kg/min. The dose of ATP required to abolish these arrhythmias averaged 1.64 +/- 0.67 mg/kg/min. ATP had not only an antiarrhythmic effect but also antagonized epinephrine-induced increases in heart rate, systemic vascular resistance, mean arterial blood pressure, and further increased cardiac index. ATP had, however, no significant effect on epinephrine-induced increases in myocardial contractility.

Adenosine Triphosphate↗
PubMedDate not supplied

Retrospective comparison of photorefractive keratectomy and radial keratotomy.

BACKGROUND: The efficacy and predictability of photorefractive keratectomy and radial keratotomy become increasingly relevant. This retrospective study compares one surgeon's experience with photorefractive keratectomy and radial keratotomy over a 3-year period from 1990 to 1993. METHODS: Photorefractive keratectomy was performed on 103 eyes of 76 patients that met the inclusion criteria for the phase IIb, phase III, and phototherapeutic keratectomy studies as delineated by the United States Food and Drug Administration. Radial keratotomy was performed on 117 eyes of 81 patients with up to 9.00 diopters (D) of myopia. RESULTS: In the photorefractive keratectomy group, 83% of the eyes achieved uncorrected visual acuity of at least 20/40; 37% saw 20/20; 88% had a refraction within 1.00 D of emmetropia, and 63% within 0.50 D of emmetropia. For the radial keratotomy group, 85% of the eyes achieved an uncorrected visual acuity of 20/40 or better; 27% saw 20/20; 88% had a refraction within 1.00 D of emmetropia; and 55% within 0.50 D of emmetropia. There were no serious complications, and only one single eye in each of the photorefractive keratectomy and radial keratotomy groups lost two lines or more of spectacle-corrected visual acuity. CONCLUSION: Photorefractive keratectomy and radial keratotomy are both effective procedures, and result in similar refractive outcomes for myopia of -1.00 to -9.00 D.

Adult↗
PubMedDate not supplied

Anti-promotion effect of chlorophyllin in DMBA-TPA-induced mouse skin carcinogenesis.

This study aimed to elucidate the inhibitory effects of chlorophyllin (CHL) at different promotion stages in a DMBA-TPA-induced mouse skin carcinogenesis model. TPA promotion was undertaken for 6, 18 and 24 weeks, respectively. Proliferating activity was observed immunohistochemically and the ornithine decarboxylase (ODC) mRNA level was analyzed by reverse transcriptase-polymerase chain reaction. Messenger RNAs for c-fos, c-jun and jun-B were also observed. CHL treatment clearly reduced proliferating activity and the level of ODC mRNA at the 18-week-promotion stage. When promoted for 24 weeks, CHL was not effective in reducing proliferating activity and ODC mRNA expression. These results indicate that the promotion stage of each target tissue should be considered in a chemopreventive program.

9,10-Dimethyl-1,2-benzanthracene↗