376
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Wen J, Cheng J. [Image displacement elimination method in tomosynthesis]. ZHONGGUO YI LIAO QI XIE ZA ZHI = CHINESE JOURNAL OF MEDICAL INSTRUMENTATION 1999; 23:12-15. [PMID: 12583030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Computerized Tomography needs projected images from all directions, tomosynthesis doesn't need the information from all directions, but its reconstruction image is indistinct. In this paper, we introduce Frequency Domain Deconvolution Imaging(FDDI) which proposed recently. FDDI overcomes shortcoming of tomosynthesis, but FDDI's calculation is large, and its zero frequency will lose. We propose a new method-image displacement elimination method(IDEM), it overcome shortcomings of FDDI and can solve convolution equation set in space domain quickly.
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377
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Cong YS, Wen J, Bacchetti S. The human telomerase catalytic subunit hTERT: organization of the gene and characterization of the promoter. Hum Mol Genet 1999; 8:137-42. [PMID: 9887342 DOI: 10.1093/hmg/8.1.137] [Citation(s) in RCA: 353] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Telomerase, the enzyme that synthesizes telomeric DNA, is not expressed in most human somatic cells but is activated with in vitro immortalization and during tumorigenesis, and repressed by cell differentiation. Of the two components of the core enzyme, the catalytic protein hTERT is limiting for activity. To investigate mechanisms of hTERT gene regulation, we have cloned genomic sequences encompassing the complete hTERT transcription unit. The hTERT gene consists of 16 exons and 15 introns spanning approximately 35 kb. Transient transfections of immortal human cells with potential regulatory 5' sequences linked to a reporter, combined with deletion analysis of these sequences, indicated that elements responsible for promoter activity are contained within a region extending from 330 bp upstream of the ATG to the second exon of the gene. Assays in different cell types have shown that the hTERT promoter is inactive in normal and in transformed pre-immortal cells, but, like telomerase, it is activated with cell immortalization. Sequence analysis revealed that the hTERT promoter is GC-rich, lacks TATA and CAAT boxes but contains binding sites for several transcription factors that may be involved in its regulation. The abundance of these sites suggests the possibility that hTERT expression may be subject to multiple levels of control and be regulated by different factors in different cellular contexts.
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378
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Wu X, Wen J, Wong WH. Conditional entropy coding of VQ indexes for image compression. IEEE TRANSACTIONS ON IMAGE PROCESSING : A PUBLICATION OF THE IEEE SIGNAL PROCESSING SOCIETY 1999; 8:1005-1013. [PMID: 18267516 DOI: 10.1109/83.777082] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Block sizes of practical vector quantization (VQ) image coders are not large enough to exploit all high-order statistical dependencies among pixels. Therefore, adaptive entropy coding of VQ indexes via statistical context modeling can significantly reduce the bit rate of VQ coders for given distortion. Address VQ was a pioneer work in this direction. In this paper we develop a framework of conditional entropy coding of VQ indexes (CECOVI) based on a simple Bayesian-type method of estimating probabilities conditioned on causal contexts, CECOVI is conceptually cleaner and algorithmically more efficient than address VQ, with address-VQ technique being its special case. It reduces the bit rate of address VQ by more than 20% for the same distortion, and does so at only a tiny fraction of address VQ's computational cost.
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379
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Iwanaga Y, Wen J, Thollander MS, Kost LJ, Thomforde GM, Allen RG, Phillips SF. Scintigraphic measurement of regional gastrointestinal transit in the dog. THE AMERICAN JOURNAL OF PHYSIOLOGY 1998; 275:G904-10. [PMID: 9815018 DOI: 10.1152/ajpgi.1998.275.5.g904] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Scintigraphic techniques can measure sequentially gastric emptying, small bowel transit, and colonic transit in humans, and comparable methods for experimental studies in animals would be useful. We developed such a method in dogs and examined the effects of prokinetic drugs on regional transit. Two isotopes were given to fasting dogs. Polystyrene pellets labeled with 99mTc were mixed in a can of dog food and 111In- labeled pellets were given in a gelatin capsule coated with a pH-sensitive polymer, designed to dissolve in the distal bowel. Gamma camera images were obtained for up to 24 h. Prokinetic drugs were given by intravenous injection. Duplicate baseline studies showed good agreement in seven dogs. In a second group (n = 4), intra- and interanimal variabilities were established. Two novel prokinetic drugs (AU-116 and AU-130) accelerated small bowel and colonic transit. A simple noninvasive method for measuring whole gut transit in dogs was developed and validated. Two new prokinetics accelerated small bowel and colonic transit.
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380
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Li T, Narhi LO, Wen J, Philo JS, Sitney K, Inoue J, Yamamoto T, Arakawa T. Interactions between NFkappaB and its inhibitor ikappaB: biophysical characterization of a NFkappaB/ikappaB-alpha complex. JOURNAL OF PROTEIN CHEMISTRY 1998; 17:757-63. [PMID: 9988522 DOI: 10.1023/a:1020770000344] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The N-terminal domain (1-318 amino acids) of mouse NFkappaB (p65) has been purified to homogeneity from the soluble fraction of Escherichia coli cells expressing this protein. Its complex with a full-length ikappaB-alpha (MAD3, 1-317 amino acids) molecule was generated by binding the E. coli-derived ikappaB-alpha to the purified NFkappaB and purifying the complex by sequential chromatography. The stoichiometry of NFkappaB to ikappaB in the complex was determined to be 2 to 1 by light scattering and SDS-polyacrylamide gel electrophoresis. The secondary structure of the NFkappaB (p65) determined by Fourier-transform infrared (FTIR) spectroscopy is in good agreement with that of the p50 in the crystal structure of the p50/DNA complex, indicating that no significant structural change in NFkappaB occurs upon binding of DNA. The FTIR spectrum of the NFkappaB/ikappaB complex indicates that its secondary structure is composed of 17% alpha-helix, 39% beta-strand, 18% irregular structures, and 26% beta-turns and loops. By comparing these data to the FTIR data for NFkappaB alone, it is concluded that the ikappaB (MAD3) in the complex contains 35% alpha-helix, 27% beta-strand, 22% irregular structures, and 16% beta-turns and loops. Circular dichroism (CD) analysis of a shorter form of ikappaB (pp40) indicates that it contains at least 20% alpha-helix and that the ikappaB subunit accounts for nearly all of the alpha-helix present in the NFkappaB/ikappaB complex, consistent with the FTIR results. The stabilities of NFkappaB, ikappaB, and their complex against heat-induced denaturation were investigated by following changes in CD signal. The results indicate that the thermal stability of ikappaB is enhanced upon the formation of the NFkappaB/ikappaB complex.
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381
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Horan TP, Simonet L, Jacobsen R, Mann M, Haniu M, Wen J, Arakawa T, Kuwamoto M, Martin F. Coexpression of G-CSF with an unglycosylated G-CSF receptor mutant results in secretion of a stable complex. Protein Expr Purif 1998; 14:45-53. [PMID: 9758750 DOI: 10.1006/prep.1998.0942] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Previously, we have shown that the entire extracellular domain of the granulocyte-colony stimulating factor receptor (sG-CSFr) produced in Chinese hamster ovary (CHO) cells forms a stable complex with its ligand G-CSF, at a stoichiometry of 2:2. A truncated receptor molecule consisting of the cytokine receptor homology domain and N-terminus Ig-like domain (Ig CRH) behaves quite similarly. Both of these forms of the receptor are highly glycosylated. To address the importance of glycosylation toward receptor activity and stability, and possibly obtain nonglycosylated receptor for crystallization, mutations were made to replace four Asn residues which are N-glycosylated in the truncated receptor. Virtually no receptor was recovered from conditioned media of CHO cells transfected with this mutant construct, although a high-level of mRNA coding for receptor was detected; this mRNA was translated as determined by Western blots of cell lysates. These results indicate that the translated product is apparently not secreted from these cells. Cells transfected with mutant receptor cDNA were cotransfected with a cDNA construct expressing G-CSF in which the single O-glycosylation site was eliminated by mutation. Upon fermentation of the cotransfectants, we observed a large amount of receptor-ligand complex in the conditioned media. The purified unglycosylated complex appeared to be of the same binding stoichiometry and approximate binding affinity as that of complex formed by addition of purified ligand and unmutated receptor. These results show that while glycosylation of sG-CSFr is not necessary for ligand binding, it appears to be crucial in folding and export from the cell.
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Zhu Y, Aletta JM, Wen J, Zhang X, Higgins D, Rubin RP. Rat serum induces a differentiated phenotype in a rat parotid acinar cell line. THE AMERICAN JOURNAL OF PHYSIOLOGY 1998; 275:G259-68. [PMID: 9688653 DOI: 10.1152/ajpgi.1998.275.2.g259] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
To establish a continuous cell line, freshly prepared rat parotid acinar cells were stably transfected with a plasmid vector containing the SV40 large T antigen. The acinar origin of these cells was confirmed by Western blotting, enzyme analysis, and morphological analysis. Transformed cells grown in 10% rat serum showed a modest reduction in cell number after 7 days and a concentration- and time-dependent increase in amylase levels approximately 16 times greater than those observed in fetal bovine serum-treated cells. Ultrastructural analysis revealed that cells grown in rat serum harbored protein-filled secretory granules localized adjacent to the endoplasmic reticulum, and punctate amylase-specific immunofluorescence distributed throughout the cytoplasm was consistent with the presence of amylase in secretory organelles. Clonal cells express tissue-specific proline-rich proteins and the four protein kinase C isozymes present in primary culture. Carbachol and isoproterenol stimulated [3H]protein secretion and isoproterenol enhanced amylase secretion from cells grown in rat serum. Moreover, norepinephrine, carbachol, and substance P produced a time- and concentration-dependent rise in cytoplasmic Ca2+. This continuous cell line of parotid acinar cells, which after treatment with rat serum retains the basic structural and functional properties of primary culture cells, will be utilized as a model system for studying long-term biological processes that regulate parotid cell function.
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383
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Wen J, Cong YS, Bacchetti S. Reconstitution of wild-type or mutant telomerase activity in telomerase-negative immortal human cells. Hum Mol Genet 1998; 7:1137-41. [PMID: 9618172 DOI: 10.1093/hmg/7.7.1137] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Telomere shortening in human somatic cells and telomere maintenance in most human immortal cell lines and tumours correlate respectively with the absence and presence of telomerase, the enzyme that synthesizes telomeric DNA de novo . However, approximately 30% of in vitro immortalized human cell lines do not express this enzyme and maintain telomeres by an alternative pathway (ALT) that may also operate in some tumours. Human telomerase is a reverse transcriptase comprising minimally an RNA subunit (hTER) and a catalytic protein moiety (hTERT). Normal somatic cells retain expression of hTER but not of hTERT, and can be converted to a telomerase-positive phenotype by ectopic expression of the catalytic protein. We similarly have restored enzymatic activity to those ALT cell lines that retain hTER expression. We also report that in those ALT cells that are hTER negative, reintroduction of both hTER and hTERT is necessary and sufficient for conversion to telomerase positivity. Moreover, transfection of these cells with hTERT in conjunction with hTERs with a mutated template results in the expression of an enzyme with altered specificity. Reconstitution of telomerase activity in ALT cells, particularly an activity capable of synthesizing mutant telomeric DNA, may be exploited for the study of the ALT mechanism and its interaction with the telomerase-dependent pathway, and for assessing the effects of mutant telomeres on cell viability.
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384
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Wen J, Shi S, Jansen R, Zimmer E. Phylogeny and biogeography of Aralia sect. Aralia (Araliaceae). AMERICAN JOURNAL OF BOTANY 1998. [PMID: 21684970 DOI: 10.2307/2446422] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Aralia sect. Aralia (Araliaceae) consists of approximately eight species disjunctly distributed in Asia and North America. Phylogenetic and biogeographic analyses were conducted using sequences of the internal transcribed spacer regions of the nuclear ribosomal DNA. Aralia racemosa from eastern North America was sister to A. californica from western North America. Aralia cordata from eastern Asia did not form a species-pair relationship with the eastern North American A. racemosa. The two subspecies of A. racemosa formed a monophyletic group. Biogeographic analyses showed a close area relationship between eastern North America and western North America. The Himalayas were cladistically basal and eastern Asia was placed between the Himalayas and North America. The biogeographic analysis supported the origin of the eastern Asian and eastern North American disjunct pattern in Aralia sect. Aralia via the Bering land bridges. Comparisons with results of phylogenetic analyses of other genera suggested that (1) the floristic connection between eastern North America and western North America may be stronger than previously thought; and (2) the biogeographic patterns in the Northern Hemisphere are complex. Furthermore, a lack of correlation between sequence divergence values and phylogenetic positions was observed, suggesting the importance of a phylogenetic framework in biogeographic analyses.
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385
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Wen J, Liang F, Du F. [An etiological and serological study on Dengue epidemic in Guangdong Province]. ZHONGHUA SHI YAN HE LIN CHUANG BING DU XUE ZA ZHI = ZHONGHUA SHIYAN HE LINCHUANG BINGDUXUE ZAZHI = CHINESE JOURNAL OF EXPERIMENTAL AND CLINICAL VIROLOGY 1998; 12:165-8. [PMID: 12515199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Abstract
In 1978-1995, Dengue fever epidemics(serotype 1-4) occurred in Guangdong Province. Among 9 species of mosquitoes found in the epidemic areas, the positive rate of virus isolation in Aedes albopictus was 20.69%, in Aedes aegypti 18.95%, in Culex quinquefasciatus 10.29%, Dengue viruses were not isolated in other 6 species of mosquitoes. The positive rate of virus isolation in the three species showed no significant differences (chi 2 = 2.77 P > 0.05). Aedes aegypti was the main transmitting vector in Hainan Island and Zhanjiang District, whereas Aedes albopictus was in the other epidemic areas. The positive rate of virus isolation within 3 days of disease onset was between 73.58% and 82.05%, but the virus could still be isolated on the 8th day of disease onset. The highest antibody positive rate from the patients' paired-sera was 93.89% and the lowest was 33.71%. IgM antibody could be detected 5 days after the disease onset in some cases, even on the 33rd day of disease onset. These results suggest that virus isolation by collecting patient's blood within 1-4 days of disease onset, or IgM antibody detection after 5 days of disease onset can be used as method for early and rapid diagnosis of the disease.
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386
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Xue L, Wen J, Zhao G. [The characteristics and significance of oncogenes expression in oval cells cultivated in vitro]. ZHONGHUA BING LI XUE ZA ZHI = CHINESE JOURNAL OF PATHOLOGY 1998; 27:191-3. [PMID: 11244979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
OBJECTIVE To study the relationship between expression characteristics of oncogenes and transformation of the oval cells cultivated in vitro. METHODS Liver oval cells of SD rats induced by feeding with chemical carcinogen 3'-Me-DAB for four weeks were isolated using Percoll density gradient centrifugation. The cells were continuously cultivated in vitro and the dynamic characteristics of Ha-ras, Ki-ras and c-myc genes expression in the oval cells were detected using RNA-DNA slot blot hybridization. RESULTS During long term cultivation, the population doubling time of the cells became shorter and the percentage of aneuploidy chromosomes and colonies grown in soft agar increased. Ha-ras Ki-ras and c-myc were synchronically expressed in the oval cells from different passages. CONCLUSION The activation and synergistic over-expression of Ha-ras Ki-ras and c-myc had an important role in the proliferation and transformation of oval cells in vitro.
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387
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Webb DJ, Wen J, Karns LR, Kurilla MG, Gonias SL. Localization of the binding site for transforming growth factor-beta in human alpha2-macroglobulin to a 20-kDa peptide that also contains the bait region. J Biol Chem 1998; 273:13339-46. [PMID: 9582381 DOI: 10.1074/jbc.273.21.13339] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
alpha2-Macroglobulin (alpha2M) functions as a major carrier of transforming growth factor-beta (TGF-beta) in vivo. The goal of this investigation was to characterize the TGF-beta-binding site in alpha2M. Human alpha2M, which was reduced and denatured to generate 180-kDa subunits, bound TGF-beta1, TGF-beta2, and NGF-beta in ligand blotting experiments. Cytokine binding was not detected with bovine serum albumin that had been reduced and alkylated, and only minimal binding was detected with purified murinoglobulin. To localize the TGF-beta-binding site in alpha2M, five cDNA fragments, collectively encoding amino acids 122-1302, were expressed as glutathione S-transferase (GST) fusion proteins. In ligand blotting experiments, TGF-beta2 bound only to the fusion protein (FP3) that includes amino acids 614-797. FP3 bound 125I-TGF-beta1 and 125I-TGF-beta2 in solution, preventing the binding of these growth factors to immobilized alpha2M-methylamine (alpha2M-MA). The IC50 values were 33 +/- 5 and 26 +/- 6 nM for TGF-beta1 and TGF-beta2, respectively; these values were comparable with or lower than those determined with native alpha2M or alpha2M-MA. A GST fusion protein that includes amino acids 798-1082 of alpha2M (FP4) and purified GST did not inhibit the binding of TGF-beta to immobilized alpha2M-MA. FP3 (0.2 microM) neutralized the activity of TGF-beta1 and TGF-beta2 in fetal bovine heart endothelial (FBHE) cell proliferation assays; FP4 was inactive in this assay. FP3 also increased NO synthesis by RAW 264.7 cells, mimicking an alpha2M activity that has been attributed to the neutralization of endogenously synthesized TGF-beta. Thus, we have isolated a peptide corresponding to 13% of the alpha2M sequence that binds TGF-beta and neutralizes the activity of TGF-beta in two separate biological assays.
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388
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Xia X, Jiang Y, Huang P, Wu Z, Zeng Q, Wen J. [Cytotoxic effect of mitomycin C on the nonpigmented epithelium of ciliary body in rabbit eyes]. [ZHONGHUA YAN KE ZA ZHI] CHINESE JOURNAL OF OPHTHALMOLOGY 1998; 34:190-3, 12. [PMID: 11877186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
OBJECTIVE To observe pathomorphological changes of nonpigmented epithelial cells (NECs) of ciliary body after local single application of mitomycin C (MMC) during sclerectomy in rabbit eyes, and to explore cytotoxic effect of MMC on ciliary body. METHODS A single five minutes intraoperative exposure to the agent MMC (0.2 mg/ml, 0.1 ml) was used during sclerectomy in rabbit eyes. The treated area was rinsed with 20 ml normal saline. The NECs of ciliary body at the operated area were observed under light microscope and transmission electron microscope on the 7th and 28th day postoperatively. RESULTS On the 7th day postoperatively, the NECs were swollen, and the intracellular abundant mitochondria were swollen and vacuolized. String pearls-like membrane-encapsulated vacuoles were present in the intervals of beta-cell membrane of the NECs. On the 28th day postoperatively, these damages were gradually recovered. CONCLUSIONS These findings suggest a toxic effect of MMC on the NECs of ciliary body, possibly that can decrease the aqueous production and intraocular pressure, even causing persistent hypotony.
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389
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Wang YP, Kolb A, Buck M, Wen J, O'Gara F, Buc H. CRP interacts with promoter-bound sigma54 RNA polymerase and blocks transcriptional activation of the dctA promoter. EMBO J 1998; 17:786-96. [PMID: 9451003 PMCID: PMC1170427 DOI: 10.1093/emboj/17.3.786] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The cAMP receptor protein (CRP) is an activator of sigma70-dependent transcription. Analysis of the sigma54-dependent dctA promoter reveals a novel negative regulatory function for CRP. CRP can bind to two distant sites of the dctA promoter, sites which overlap the upstream activator sequences for the DctD activator. CRP interacts with Esigma54 bound at the dctA promoter via DNA loop formation. When the CRP-binding sites are deleted, CRP still interacts in a cAMP-dependent manner with the stable Esigma54 closed complex via protein-protein contacts. CRP is able to repress activation of the dctA promoter, even in the absence of specific CRP-binding sites. CRP affects both the final level and the kinetics of activation. The establishment of the repression and its release by the NtrC activator proceed via slow processes. The kinetics suggest that CRP favours a new form of closed complex which interconverts slowly with the classical closed intermediate. Only the latter is capable of interacting with an activator to form an open promoter complex. Thus, Esigma54 promoters are responsive to CRP, a protein unrelated to sigma54 activators, and the repression exerted is the direct result of an interaction between Esigma54 and the CRP-cAMP complex.
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390
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Wen J, Luque-de Leon E, Kost LJ, Sarr MG, Phillips SF. Duodenal motility in fasting dogs: humoral and neural pathways mediating the colonic brake. THE AMERICAN JOURNAL OF PHYSIOLOGY 1998; 274:G192-5. [PMID: 9458789 DOI: 10.1152/ajpgi.1998.274.1.g192] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
We have previously described a negative feedback loop that inhibits duodenal motility when nutrients are infused into the ileum and colon. In the present study, we examined the role of extrinsic innervation and plasma levels of peptide YY (PYY) in mediating this phenomenon. We perfused neurally intact (n = 5 dogs) or extrinsically denervated (n = 6 dogs) isolated loops of proximal colon with isomolar NaCl or a mixed-nutrient solution at 2 and 6 ml/min for 4 h during fasting or for 2 h beginning 15 min after a meal. Both rates of infusion with NaCl prolonged the cycle length of the duodenal migrating motor complex (MMC) in the group with neurally intact loops but not in the group with extrinsically denervated loops. Nutrient infusions increased the MMC cycle length in both groups. Integrated plasma concentrations of PYY were increased by nutrients but not by NaCl in both groups. These data suggest that increased volumes and unabsorbed nutrients in the proximal colon alter proximal small bowel motility. Volume-induced effects are mediated via extrinsic nerves, whereas nutrient-induced effects may be mediated by humoral factors, such as plasma PYY.
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392
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Wen J, Vanek-Krebitz M, Hoffmann-Sommergruber K, Scheiner O, Breiteneder H. The potential of Betv1 homologues, a nuclear multigene family, as phylogenetic markers in flowering plants. Mol Phylogenet Evol 1997; 8:317-33. [PMID: 9417891 DOI: 10.1006/mpev.1997.0447] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Betv1 homologues are a ubiquitous group of genes in flowering plants encoding a class of highly conserved defense-related proteins and containing open reading frames from 465 to 480 bp. Betv1-like genes consist of two exons interrupted by an intron of 76-359 bp, with the intron position highly conserved. The pairwise p distance ranged from 0 to 0.583 among flowering plants. Within plant families, the ranges of the p distance were 0-0.403, 0-0.253, and 0.011-0.369, for Apiaceae, Betulaceae, and Fabaceae, respectively. The most striking feature of the betv1 gene phylogeny was that the multiple sequences from each plant family formed a monophyletic group and sequences from each species were generally more similar to each other than those from other species. The almost exclusive paralogous relationships of genes from the same species suggested that the genes of the multigene family underwent strong concerted evolution. Phylogenies of Betulaceae and Fabaceae inferred from betv1 gene trees were generally congruent with those based on morphology and other molecules. Betv1 homologues constitute potential phylogenetic markers at the intrafamilial level or among closely related families in flowering plants.
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Hu Q, Marand E, Dhingra S, Fritsch D, Wen J, Wilkes G. Poly(amide-imide)/TiO2 nano-composite gas separation membranes: Fabrication and characterization. J Memb Sci 1997. [DOI: 10.1016/s0376-7388(97)00120-8] [Citation(s) in RCA: 178] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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394
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Wen J, Lu X, Wei Y, Zhou F. [Studies on the chemical constituent of Ephedra likiangensis]. ZHONG YAO CAI = ZHONGYAOCAI = JOURNAL OF CHINESE MEDICINAL MATERIALS 1997; 20:512-4. [PMID: 12572520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/20/2023]
Abstract
Six crystalline substances were isolated from the stem of Ephedra likiangensis Florin and were identified as ephedrine (I), beta-sitosterol (II), palmitic acid (IV), stearic acid (V), cerotic acid (III) and beta-daucosterol (VI).
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395
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Narhi LO, Rosenfeld R, Shimamoto G, Lee R, Hawkins N, Li T, Philo J, Wen J, Arakawa T. Comparison of solution properties of human and rat ciliary neurotrophic factor. THE JOURNAL OF PEPTIDE RESEARCH : OFFICIAL JOURNAL OF THE AMERICAN PEPTIDE SOCIETY 1997; 50:300-9. [PMID: 9352468 DOI: 10.1111/j.1399-3011.1997.tb01471.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The solution structure and stability of rat and human ciliary neurotrophic factor (CNTF) were examined by circular dichroism (CD), Fourier transform infrared (FTIR) and fluorescence spectroscopy and sedimentation equilibrium analyses. The secondary structure of both proteins, as assessed by CD and FTIR, consists primarily of alpha-helix, consistent with CNTF being a member of the four-helical bundle family of cytokines and neurokines, with rat CNTF containing slightly less helix (about 10% less) and slightly more disordered structure. The environment of the tyrosine and tryptophan residues, assessed by intrinsic fluorescence emission spectroscopy, appears to be the same in both proteins. Binding of anilinonaphthalene sulfonate is identical for both proteins, indicating that these two proteins have similar surface hydrophobicities in the native state. The thermal stability of the human CNTF is significantly less than that of the rat CNTF, yet their stabilities to guanidine HCl-induced denaturation are equivalent. This apparent discrepancy in stability between the two proteins may be explained by solubility differences upon thermal unfolding. Although the human protein precipitates as it is denatured by heat, the rat protein does not. It thus appears that the unfolded state of human CNTF is less soluble and more prone to aggregation than that of the rat protein upon heating, although their conformational stability is similar. Both proteins remain largely folded at pH 3.0. Sedimentation equilibrium analysis demonstrates that both rat and human CNTF exist primarily as monomers; however, significant dimer formation occurs as the protein concentrations are increased to greater than 3 mg/mL, particularly in the presence of ammonium sulfate.
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396
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Zhang X, Wen J, Bidasee KR, Besch HR, Rubin RP. Ryanodine receptor expression is associated with intracellular Ca2+ release in rat parotid acinar cells. THE AMERICAN JOURNAL OF PHYSIOLOGY 1997; 273:C1306-14. [PMID: 9357775 DOI: 10.1152/ajpcell.1997.273.4.c1306] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The ryanodine receptor mediates intracellular Ca2+ mobilization in muscle and nerve, but its physiological role in nonexcitable cells is less well defined. Like adenosine 3',5'-cyclic monophosphate and inositol 1,4,5-trisphosphate, cyclic ADP-ribose (0.3-5 microM) and ADP (1-25 microM) produced a concentration-dependent rise in cytosolic Ca2+ in permeabilized rat parotid acinar cells. Adenosine and AMP were less effective. Ryanodine markedly depressed the Ca2+-mobilizing action of the adenine nucleotides and forskolin in permeabilized cells and was likewise effective in depressing the action of forskolin in intact cells. Cyclic ADP-ribose-evoked Ca2+ release was enhanced by calmodulin and depressed by W-7, a calmodulin inhibitor. A fluorescently labeled ligand, 4,4-difluoro-1,3,5,7-tetramethyl-4-bora-3,4-diaza-s-indac ene-3-propionic acid-glycyl ryanodine, was synthesized to detect the expression and distribution of ryanodine receptors. In addition, ryanodine receptor expression was detected in rat parotid cells with a sequence highly homologous to a rat skeletal muscle type 1 and a novel brain type 1 ryanodine receptor. These findings demonstrate the presence of a ryanodine-sensitive intracellular Ca2+ store in rat parotid cells that shares many of the characteristics of stores in muscle and nerve and may mediate Ca2+-induced Ca2+ release or a modified form of this process.
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397
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Wen J, Xie D, Yao J. [Promotive effect of TNF-alpha and M-CSF on osteolysis induced by giant cell tumor of bone]. ZHONGHUA BING LI XUE ZA ZHI = CHINESE JOURNAL OF PATHOLOGY 1997; 26:273-6. [PMID: 10374334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
OBJECTIVE To explore the effect of cell components in giant cell tumor of bone (GCT) and cytokines expressed by them on osteolysis. METHODS Mononuclear stromal cells and multinucleated giant cells (MGCs) were isolated from 10 cases of GCT, and fibroblast-like stromal cells were obtained by long-term culture of mononuclear stromal cells. Osteolytic capability of above isolated cells were tested in an in vitro cell-bone resorption model. RESULTS All cell components isolated from GCT had capability to resorb bone matrix directly. Exogenous tumore necrosis factor-alpha (TNF-alpha) could significantly increase the bone resorption induced by both kinds of stromal cell. There were higher level of TNF-alpha and greater expression rate of macrophage colony stimulating factor (M-CSF) in GCT than in the osteosarcoma tissues or the normal serum. CONCLUSIONS The characteristic bone resorption behavior of GCT might be conducted by all it's three major cell components, and this bone resorption process could be promoted by both TNF-alpha and M-CSF they expressed.
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398
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Hoffmann-Sommergruber K, Vanek-Krebitz M, Radauer C, Wen J, Ferreira F, Scheiner O, Breiteneder H. Genomic characterization of members of the Bet v 1 family: genes coding for allergens and pathogenesis-related proteins share intron positions. Gene 1997; 197:91-100. [PMID: 9332353 DOI: 10.1016/s0378-1119(97)00246-1] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Bet v 1, the major birch pollen allergen, is a member of a multigene family; a number of isoforms and homologous proteins from closely related species (alder, hazel and hornbeam) has been isolated and their cDNAs cloned and characterized. Genomic clones coding for Bet v 1 and homologues from apple and hazel were isolated and sequenced. Some of these clones contained intervening sequences. The exon-intron formation is highly conserved throughout this family of pathogenesis-related proteins in dicot plants and is also found in Aopr1 (Asparagus officinalis), a monocol species. Phylogenetic analysis suggested a possible common origin of the intron position in these homologous proteins at codon 62 in various families of flowering plants, including Fagaceae, Rosaceae and Apiaceae. This conserved 'proto-splice site' may point to a structure/function relationship. A conserved sequence motif (P-loop) was also found in all members of this protein family. Moreover, there is a certain degree of sequence similarity among the proteins derived from various species throughout the dicots and the only monocot examined. This fact is reflected by cross-reactivity from monoclonal and polyclonal antibodies raised against Bet v 1.
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Qiu M, Liu W, Liu G, Wen J, Liu G, Chang S. [Thermoregulation under simulated weightlessness]. HANG TIAN YI XUE YU YI XUE GONG CHENG = SPACE MEDICINE & MEDICAL ENGINEERING 1997; 10:210-3. [PMID: 11540574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
The effect of simulated weightlessness on thermoregulation was studied in 5 subjects. The experiment consisted of 3d baseline measurements, 7d head-down bed rest and 2d recovery. Circadian rhythm was assessed by continuous measurements of rectal temperature and skin temperature with 2h intervals. Heat Stress Protein 70 (HSP70) was measured by Western-blot Dot method and the facial surface temperature distribution was measured by HR-2 infrared thermography. The results showed that rectal temperature keeps the wake-sleep variation, but the circadian rhythm changed during bed rest, and the change of rectum temperature rhythm appeared mainly in the early-days of bed rest; HSP70 and facial surface temperature increased during bed rest.
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