501
|
Tornow J, Zeng X, Gao W, Santangelo GM. GCR1, a transcriptional activator in Saccharomyces cerevisiae, complexes with RAP1 and can function without its DNA binding domain. EMBO J 1993; 12:2431-7. [PMID: 8508768 PMCID: PMC413478 DOI: 10.1002/j.1460-2075.1993.tb05897.x] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
In Saccharomyces cerevisiae, efficient expression of glycolytic and translational component genes requires two DNA binding proteins, RAP1 (which binds to UASRPG) and GCR1 (which binds to the CT box). We generated deletions in GCR1 to test the validity of several different models for GCR1 function. We report here that the C-terminal half of GCR1, which includes the domain required for DNA binding to the CT box in vitro, can be removed without affecting GCR1-dependent transcription of either the glycolytic gene ADH1 or the translational component genes TEF1 and TEF2. We have also identified an activation domain within a segment of the GCR1 protein (the N-terminal third) that is essential for in vivo function. RAP1 and GCR1 can be co-immunoprecipitated from whole cell extracts, suggesting that they form a complex in vivo. The data are most consistent with a model in which GCR1 is attracted to DNA through contact with RAP1.
Collapse
Affiliation(s)
- J Tornow
- Department of Biological Sciences, University of Southern Mississippi, Hattiesburg 39406-5018
| | | | | | | |
Collapse
|
502
|
|
503
|
Zeng X, Farrenkopf B, Hohmann S, Dyda F, Furey W, Jordan F. Role of cysteines in the activation and inactivation of brewers' yeast pyruvate decarboxylase investigated with a PDC1-PDC6 fusion protein. Biochemistry 1993; 32:2704-9. [PMID: 8448127 DOI: 10.1021/bi00061a031] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Possible roles of the Cys side chains in the activation and inactivation mechanisms of brewers' yeast pyruvate decarboxylase were investigated by comparing the behavior of the tetrameric enzyme pdc1 containing four cysteines/subunit (positions 69, 152, 221, and 222) with that of a fusion enzyme (pdc1-6, a result of spontaneous gene fusion between PDC1 and PDC6 genes) that is 84% identical in sequence with pdc1 and has only Cys221 (the other three Cys being replaced by aliphatic side chains). The two forms of the enzyme are rather similar so far as steady-state kinetic parameters and substrate activation are considered, as tested for activation by the substrate surrogate pyruvamide. Therefore, if a cysteine is responsible for substrate activation, it must be Cys221. The inactivation of the two enzymes was tested with several inhibitors. Methylmethanethiol sulfonate, a broad spectrum sulfhydryl reagent, could substantially inactivate both enzymes, but was slightly less effective toward the fusion enzyme. (p-Nitrobenzoyl)formic acid is an excellent alternate substrate, whose decarboxylation product p-nitrobenzaldehyde inhibited both enzymes possibly at a Cys221, the only one still present in the fusion enzyme. Exposure of the fusion enzyme, just as of pdc1, to (E)-2-oxo-4-phenyl-3-butenoic acid type inhibitors/alternate substrates enabled detection of the enzyme-bound enamine intermediate at 440 nm. However, unlike pdc1, the fusion enzyme was not irreversibly inactivated by these substrates. These substrates are now known to cause inactivation of pdc1 with concomitant modification of one Cys of the four [Zeng, X.; Chung, A.; Haran, M.; Jordan, F. (1991) J. Am. Chem. Soc. 113, 5842-49].(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- X Zeng
- Department of Chemistry, Rutgers, the State University, Newark, New Jersey 07102
| | | | | | | | | | | |
Collapse
|
504
|
Zhang Y, Zheng Z, Zeng X, Tan J, Wu J. [Antisteatotic effects of four kinds of dietary fibers in rats fed on high cholesterol diet: a preliminary morphometric analysis]. Hua Xi Yi Ke Da Xue Xue Bao 1992; 23:75-8. [PMID: 1328028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The hypolipidaemic and antisteatotic effects of the Konnyaku Powder (KP) have been reported before. In order to evaluate further the antisteatotic role played by KP, the effects of KP on the levels of liver lipid and on the hepatic histopathology and morphometry in comparison with those of pectin, algin and agar were studied. Sixty Wistar strain rats were divided into 6 groups: a normal diet group, a high cholesterol diet group (HC), and 4 test groups, in which the animals were fed on a diet similar to that of the high cholesterol diet group with addition of KP, pectin, algin or agar at a dosage of 5%, respectively. All the animals were killed at the end of the diet treatment for 9 weeks. The results showed that relative liver weights were lower in four experimental groups than in the HC group. The levels of total and free cholesterol, and triglyceride in the liver were lower in KP group than in HC group and in the other three experimental groups. Hepatic histopathology and morphometric examination indicated that antisteatotic effects of KP appeared to be much more significant than those of the other fibers.
Collapse
|
505
|
Zeng X. [Observation of T cells and T-cell subsets in mycosis fungoides]. Zhongguo Yi Xue Ke Xue Yuan Xue Bao 1992; 14:75-7. [PMID: 1534285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Skin lesions from 14 patients with mycosis fungoides (MF) were studied immunohistochemically with monoclonal antibodies that identify pan T (Leu4), T-helper/inducer (TH), T-suppressor/cytotoxic (Ts) (Leu3a, Leu2a) and pan B (Leu12) cells. Lymphoid cell reactivity was diverse among these cases. Among 12 cases of MF, TH cells were predominant over Ts cells, and one case featured nonreactive Ts cells in the dermis. In one case of MF, Ts cells were predominant. One case of MF showed strong reactivity for both T cell subset markers. The intraepidermal lymphoid cellularity was Leu4-reactive in 14 cases of MF. Among these 14 cases, the intraepidermal cellularity was Leu3a-reactive in 11 and Leu2a-reactive in 4. The use of such studies of T cell subsets may demonstrate a correlation of MF with cytomorphology, clinical stage, and disease prognosis.
Collapse
Affiliation(s)
- X Zeng
- Institute of Dermatology, Nanjing
| |
Collapse
|
506
|
Castelfranco PA, Zeng X. Regulation of 5-Aminolevulinic Acid Synthesis in Developing Chloroplasts : IV. An Endogenous Inhibitor from the Thylakoid Membranes. Plant Physiol 1991; 97:1-6. [PMID: 16668354 PMCID: PMC1080955 DOI: 10.1104/pp.97.1.1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
5-Aminolevulinic acid synthesis in isolated, intact, developing chloroplasts from greening cucumber (Cucumis sativus) cotyledons was inhibited by broken chloroplast fragments. It was shown that the inhibitory constituent was associated with the thylakoid membrane system. The inhibitor was resistant to boiling, was not a form of ribonuclease, and did not inhibit Mg-chelatase, indicating that massive organelle destruction was not involved. The inhibitor was also found in etioplast and mature chloroplasts; and it was found in barley as well as cucumber. 5-Aminolevulinate synthesis in the dark with exogenous ATP and NADPH, or in the light without added cofactors, were inhibited approximately equally. In the dark, 5-aminolevulinate synthesis and protochlorophyllide synthesis from glutamate were inhibited to about equal extent. The inhibition was decreased when the membranes were washed with aqueous acetone prior to incubation. The inhibition by the unknown factor was compared to the inhibition by gabaculine, 4-amino-5-hexynoic acid, protoheme, and glutathione. The unknown inhibitor appeared to have a number of similarities with protoheme.
Collapse
Affiliation(s)
- P A Castelfranco
- Department of Botany, University of California, Davis, California 95616-8537
| | | |
Collapse
|
507
|
Luo D, Li Y, Deng S, Zeng X. [Prophylactic effect of refined amorphophallus konjac on MNNG-induced lung cancers in mice]. Hua Xi Yi Ke Da Xue Xue Bao 1991; 22:287-91. [PMID: 1748413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Three hundred and seventy LACA mice of seven weeks old were used in 2 batches for studying the prophylactic effect of Konjaku powder on MNNG-induced lung cancers. These mice (within each batch) were randomly allocated to four groups, namely positive control (MNNG), refined Amorphophallus Konjac (R.A.K.), complex (MNNG + R.A.K.), and blank control (C). In MNNG group, MNNG (250 micrograms) was injected intravenously once five days for seven times in each mouse, the total dosage of MNNG was 1.75 mg. In R.A.K. group, according to w/w, 8% R.A.K. was well mixed into 92% common diet for long-term term breeding. In complex group, MNNG was given as that in MNNG group and the mice were reared as those in R.A.K. group. The mice in MNNG group and in C group were all reared by common diet. The results of experiments showed different degrees of preventive effect of R.A.K. on MNNG-induced lung cancers in LACA mice. R.A.K. not only exerted effect on the number of induced cancer, causing a drop of the cancerous rate from 79.75% to 20.00% and the mean number of cancer in each animal, but also prolonged the survival time of animals. At the same time, the constituent ratio of the kinds of tumor denoted a decrease in malignancy (adenoma with malignant change), an absence of adenocarcinoma and relative increase in benign adenoma. The results of experiments also exhibited good duplication as well as absence of adverse reactions to Konjaku powder.
Collapse
|
508
|
Zeng X, Yi X. [Nursing care of acute infection of the biliary tract in the aged. Report of 50 cases]. Zhonghua Hu Li Za Zhi 1991; 26:393-5. [PMID: 1959152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
|
509
|
You JQ, Zeng X, Xie T, Yan JR. Quantum Heisenberg-Ising models on generalized Fibonacci lattices. Phys Rev B Condens Matter 1991; 44:713-720. [PMID: 9999172 DOI: 10.1103/physrevb.44.713] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
|
510
|
Zeng X, Eykholt R, Pielke RA. Estimating the Lyapunov-exponent spectrum from short time series of low precision. Phys Rev Lett 1991; 66:3229-3232. [PMID: 10043734 DOI: 10.1103/physrevlett.66.3229] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
|
511
|
Li H, Zhen Z, Zeng X, Zeng L, Ke F, Yang H. [Small-airway lesions induced by inhalation of asbestos dust in dogs--pathological and aetiological studies]. Hua Xi Yi Ke Da Xue Xue Bao 1991; 22:46-50. [PMID: 1774036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
This paper presents the pathological changes of the small airways of dogs inhaling asbestos dust in the workshop of Xin Kong Asbestos Mine for 1 to 3 years. Dogs of the experimental group showed that variable degrees of dust deposition and fibrous tissue reaction were found in all the three types of the small airways-respiratory bronchioles, alveolar ducts and membranous bronchioles of both lungs. The lesions in the lung increased with the duration of exposure. These changes in the canine small airways resulting from asbestos dust were very much similar to those of the humans. In addition, deposited dust collected from the workshop of the asbestos mine, and 50 dust particles selected randomly in foci were identified in situ by energy dispersive X-ray analysis. Findings demonstrated that the majority of the dust particles in the foci was principally mixed silicate dust. Among them asbestos dust predominated absolutely, and there were more amphiboles than chrysotiles. Therefore, it is concluded that the small airway lesions induced in the dogs are mainly due to mixed asbestos dust, and that there appears to exist a dose-response relationship.
Collapse
Affiliation(s)
- H Li
- School of Public Health, Xin Kang Chrysotile Mine
| | | | | | | | | | | |
Collapse
|
512
|
Zeng X, Fang Z, Ma J. [Chemical constituents of Osbeckia chinensis L]. Zhongguo Zhong Yao Za Zhi 1991; 16:99-101, 127. [PMID: 1872973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Five constituents, 2-furoic acid, succinic acid, ursolic acid, quercetin and daucosterol were isolated and identified from Osbeckia chinensis. All of them are reported to have been found from this plant for the first time.
Collapse
Affiliation(s)
- X Zeng
- Jiangxi Institute of Materia Medica, Nanchang
| | | | | |
Collapse
|
513
|
Isayev AI, Wong CM, Zeng X. Effect of oscillations during extrusion on rheology and mechanical properties of polymers. Adv Polym Technol 1990. [DOI: 10.1002/adv.1990.060100104] [Citation(s) in RCA: 82] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
514
|
Zafiropulos V, Kleiber PD, Sando KM, Zeng X, Lyyra AM, Stwalley WC. Energy-dependent photodissociation dynamics probed by fluorescence polarization. Phys Rev Lett 1988; 61:1485-1488. [PMID: 10038810 DOI: 10.1103/physrevlett.61.1485] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
|
515
|
|
516
|
Calaprice FP, Happer W, Schreiber DF, Lowry MM, Miron E, Zeng X. Nuclear alignment and magnetic moments of 133Xe, 133Xem, and 131Xem by spin exchange with optically pumped 87Rb. Phys Rev Lett 1985; 54:174-177. [PMID: 10031432 DOI: 10.1103/physrevlett.54.174] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
|
517
|
Zeng X, Wu Z, Call T, Miron E, Schreiber D, Happer W. Experimental determination of the rate constants for spin exchange between optically pumped K, Rb, and Cs atoms and 129Xe nuclei in alkali-metal-noble-gas van der Waals molecules. Phys Rev A Gen Phys 1985; 31:260-278. [PMID: 9895475 DOI: 10.1103/physreva.31.260] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
|
518
|
Wang HY, Sun GX, Lin JZ, Liu TH, Wang SX, Zhou L, Li GR, Hu Y, Hu SS, Zeng X. [Coxsackie B4 virus murine myocarditis]. Zhongguo Yi Xue Ke Xue Yuan Xue Bao 1984; 6:300-2. [PMID: 6098385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
|
519
|
|