151
|
Zeligman BE, Howard RB, Marcell T, Chu H, Rossi RP, Mulvin D, Johnston MR. Chest roentgenographic techniques for demonstrating human lung tumour xenografts in nude rats. Lab Anim 1992; 26:100-6. [PMID: 1518275 DOI: 10.1258/002367792780745878] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Roentgenographic techniques were investigated for imaging orthotopic lung tumours in anaesthetized nude rats endobronchially implanted with human lung cancer cells. A conventional radiographic unit with a dual-screen, double-emulsion film mammographic receptor produced images preferable to those from a mammographic unit because of superior resolution. Typical exposure factors were 300 mA, 29 kVp, and 17 ms at a focus-film distance of 76 cm with a 2.11 by 2.41 mm effective focal spot and inherent filtration of 1.2 mm aluminium. Sensitivity for tumour detection was 0.93 for 59 animals with pathologically proved tumours and 0.96 for 54 animals with tumours larger than 4 mm or 50 mg. For 24 pathologically tumour-free animals, specificity was 1.00. For 55 animals radiographically judged to have tumours, positive predictive value was 1.00. For all 83 animals, accuracy was 0.95. This technique effectively demonstrates orthotopic human lung tumours in nude rats and should be useful for noninvasive monitoring of tumour presence, location, size, and changes in size.
Collapse
|
152
|
Chiou SH, Lee HJ, Chu H, Lai TA, Chang GG. Screening and kinetic analysis of delta-crystallins with endogenous argininosuccinate lyase activity in the lenses of vertebrates. BIOCHEMISTRY INTERNATIONAL 1991; 25:705-13. [PMID: 1815504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Screening of lens homogenates from the representative species of five major classes of vertebrates was undertaken to search for delta-crystallin with argininosuccinate lyase activity. Purification and biochemical characterization of delta-crystallins from the avian and reptilian species revealed differences in their electrophoretic and kinetic properties in spite of their similar tetrameric structure of about 200 kDa in the native forms. Chicken delta-crystallin, in contrast to those obtained from duck, goose and caiman, is almost devoid of the enzymatic activity. Two-dimensional gel electrophoresis of lens homogenates indicated that in the chicken lens delta-crystallin is composed of a subunit with an isoelectric point of 5.9 and a subunit mass of 50 kDa whereas that of goose lenses possesses heterogeneous subunits with isoelectric points spreading in a range of 5.9 to 6.8. Immunological comparison of inactive and active delta-crystallins from the chicken, duck and caiman lenses established the apparent structural similarity of all delta-crystallins to the authentic enzyme regarding some of common surface epitopes, yet they are not completely identical. Kinetic constants for two of the active delta-crystallins, i.e. those from the duck and goose of the Anatidae family, were also determined and their catalyzed reaction was shown to conform to a random Uni-Bi kinetic mechanism similar to that of the argininosuccinate lyase from the bovine liver.
Collapse
|
153
|
Snedecor B, Chu H, Chen E. Selection, expression, and nucleotide sequencing of the glutamate dehydrogenase gene of Peptostreptococcus asaccharolyticus. J Bacteriol 1991; 173:6162-7. [PMID: 1917850 PMCID: PMC208366 DOI: 10.1128/jb.173.19.6162-6167.1991] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The gene for the catabolic NAD-linked glutamate dehydrogenase of Peptostreptococcus asaccharolyticus was cloned by selection of Escherichia coli for complementation of a biosynthetic defect. Cloned fragments containing the gene and the P. asaccharolyticus transcription and translation signals are very highly expressed in E. coli. The nucleotide sequence of the cloned gene was determined. It codes for a polypeptide of 421 amino acids, the sequence of which is similar to those of the NADP-accepting glutamate dehydrogenases. The sequence similarity of this protein to the mammalian glutamate dehydrogenases, which accept both NADP and NAD, is greater than its similarity to the bacterial NADP-specific dehydrogenases, suggesting that this NAD-specific bacterial glutamate dehydrogenase and the NADP-specific bacterial dehydrogenases diverged separately from the line leading to the dual-specificity mammalian glutamate dehydrogenases.
Collapse
|
154
|
Howard RB, Chu H, Zeligman BE, Marcell T, Bunn PA, McLemore TL, Mulvin DW, Cowen ME, Johnston MR. Irradiated nude rat model for orthotopic human lung cancers. Cancer Res 1991; 51:3274-80. [PMID: 2040002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The development of improved animal models for biological and preclinical studies of human lung cancer is important because lung cancer is the leading cause of cancer death in the United States. To determine whether the Rowett nude rat could serve as an orthotopic (organ-specific) model of this disease, nude rats (CR: NIH-RNU), with and without 500 rads of prior gamma-irradiation, were implanted intrabronchially with 10(7) cultured cells from 3 human lung cancer lines. Without irradiation, the NCI-H460 large-cell undifferentiated carcinoma had a 54% take-rate, whereas the NCI-H125 adenosquamous carcinoma and A549 adenocarcinoma had take-rates of 7 and 33%, respectively; irradiation increased the respective take-rates to 100, 83, and 90%. In irradiated rats, tumor age versus weight measurements showed progressive growth for all three tumors, with growth rates in the order: NCI-H460 greater than A549 greater than NCI-H125, requiring approximately 3, 5, and 9 weeks, respectively, for average tumor sizes to exceed 500 mg. The small-cell carcinoma cell line NCI-H345 was implanted only into irradiated rats and resulted in more slowly growing tumors. Histopathological study showed all model tumor types to have histological characteristics consistent with the clinical tumors from which the cell lines were derived. Each tumor type had a different growth pattern, with some of the the A549- and NCI-H125-derived tumors metastasizing to contralateral lung and/or regional lymph nodes. There was no evidence for immunological rejection in irradiated, tumor-bearing rats. Nonirradiated, implanted rats without gross tumor exhibited peribronchiolar mononuclear cell infiltration with or without fibrosis, suggesting prior immunological rejection. The successful orthotopic growth of these 4 human lung cancer cell lines in irradiated nude rats suggests that this model could be useful for biological and preclinical studies of human lung cancer, both in intact rats and via ex vivo perfusion of their tumor-bearing lungs.
Collapse
|
155
|
Chu H. [Fibronectin and laminin changes in rat lungs with interstitial fibrosis]. ZHONGHUA YI XUE ZA ZHI 1991; 71:87-9. [PMID: 1711922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
|
156
|
Abstract
Diffuse, cutaneous mastocytosis is a rare variant of cutaneous mast cell infiltration that can arise in neonates or infants as a generalized bullous eruption. The mode of transmission is suggested as autosomal dominant. We report four infants from two unrelated families with diffuse cutaneous mastocytosis whose cutaneous disease was not controlled by initial therapies. Treatment of the four infants with photochemotherapy dramatically reduced or eliminated symptoms. One course of therapy resulted in improvement, and retreatment has not been required two to six years later.
Collapse
|
157
|
Chu H, Fenton EW. Cooper-pairing interaction due to magnetic fluctuations near the spin-density-wave phase transition. PHYSICAL REVIEW. B, CONDENSED MATTER 1990; 42:6408-6415. [PMID: 9994723 DOI: 10.1103/physrevb.42.6408] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
158
|
Chu H. Effect of the nearest-neighbor Coulomb interaction on d-wave Cooper pairing on a square lattice. PHYSICAL REVIEW. B, CONDENSED MATTER 1990; 42:6196-6199. [PMID: 9994696 DOI: 10.1103/physrevb.42.6196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
|
159
|
Chu H, Fenton EW. d-wave Cooper pairing near or in the spin-density-wave state. PHYSICAL REVIEW. B, CONDENSED MATTER 1990; 41:7264-7266. [PMID: 9993003 DOI: 10.1103/physrevb.41.7264] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
160
|
Deveaud B, Chomette A, Clérot F, Regreny A, Maan JC, Romestain R, Bastard G, Chu H, Chang YC. Miniband dispersion and excitonic effects on the optical spectra of GaAs/AlxGa1-xAs superlattices. PHYSICAL REVIEW. B, CONDENSED MATTER 1989; 40:5802-5805. [PMID: 9992625 DOI: 10.1103/physrevb.40.5802] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
|
161
|
Chu H, Chang YC. Line-shape theory of magnetoabsorption in semiconductor superlattices. PHYSICAL REVIEW. B, CONDENSED MATTER 1989; 40:5497-5506. [PMID: 9992581 DOI: 10.1103/physrevb.40.5497] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
|
162
|
Gu YS, Zheng XL, Cui SG, Chu H, Xu ZZ. Clinical observations on weight reduction by pressing auricular points with semen vaccariae--a report of 473 cases. J TRADIT CHIN MED 1989; 9:166. [PMID: 2615444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
|
163
|
Ren SF, Chu H, Chang YC. Phonon dispersion curves of GaAs-AlAs superlattices grown in the. PHYSICAL REVIEW. B, CONDENSED MATTER 1989; 40:3060-3065. [PMID: 9992241 DOI: 10.1103/physrevb.40.3060] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
|
164
|
Chu H, Chang YC. Theory of line shapes of exciton resonances in semiconductor superlattices. PHYSICAL REVIEW. B, CONDENSED MATTER 1989; 39:10861-10871. [PMID: 9947896 DOI: 10.1103/physrevb.39.10861] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
|
165
|
Song JJ, Jung PS, Yoon YS, Chu H, Chang YC, Tu CW. Excitons associated with subband dispersion in GaAs/AlxGa1-xAs superlattices. PHYSICAL REVIEW. B, CONDENSED MATTER 1989; 39:5562-5565. [PMID: 9948963 DOI: 10.1103/physrevb.39.5562] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
|
166
|
Chu H, Chang YC. Phonon-polariton modes in superlattices: The effect of spatial dispersion. PHYSICAL REVIEW. B, CONDENSED MATTER 1988; 38:12369-12376. [PMID: 9946177 DOI: 10.1103/physrevb.38.12369] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/11/2023]
|
167
|
Sung RJ, Huycke EC, Lai WT, Tseng CD, Chu H, Keung EC. Clinical and electrophysiologic mechanisms of exercise-induced ventricular tachyarrhythmias. Pacing Clin Electrophysiol 1988; 11:1347-57. [PMID: 2460842 DOI: 10.1111/j.1540-8159.1988.tb03999.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
|
168
|
Chu H, Ren SF, Chang YC. Long-wavelength optical phonons in polar superlattices. PHYSICAL REVIEW. B, CONDENSED MATTER 1988; 37:10746-10755. [PMID: 9944528 DOI: 10.1103/physrevb.37.10746] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/11/2023]
|
169
|
Ren SF, Chu H, Chang YC. Anisotropy of optical phonons and interface modes in GaAs-AlAs superlattices. PHYSICAL REVIEW. B, CONDENSED MATTER 1988; 37:8899-8911. [PMID: 9944260 DOI: 10.1103/physrevb.37.8899] [Citation(s) in RCA: 62] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/11/2023]
|
170
|
Chu H, Zhao SZ, Huang YY. Application of acupuncture to gastroscopy using a fibreoptic endoscope. J TRADIT CHIN MED 1987; 7:279. [PMID: 3449710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
|
171
|
Chu H, Sanders GD, Chang YC. Long-lived excitons in InAs quantum wells under uniaxial stress. PHYSICAL REVIEW. B, CONDENSED MATTER 1987; 36:7955-7963. [PMID: 9942593 DOI: 10.1103/physrevb.36.7955] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/11/2023]
|
172
|
Ren SF, Chu H, Chang YC. Anisotropy of optical phonons in GaAs-AlAs superlattices. PHYSICAL REVIEW LETTERS 1987; 59:1841-1844. [PMID: 10035345 DOI: 10.1103/physrevlett.59.1841] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
|
173
|
Lee LA, Coulter S, Erner S, Chu H. Cardiac immunoglobulin deposition in congenital heart block associated with maternal anti-Ro autoantibodies. Am J Med 1987; 83:793-6. [PMID: 3314497 DOI: 10.1016/0002-9343(87)90918-1] [Citation(s) in RCA: 116] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Isolated congenital complete heart block is frequently found in offspring of mothers who have IgG anti-Ro/SSA autoantibodies. IgG deposition was reported in the heart of a baby who died from heart block and heart failure. The pattern of antibody deposition observed was the same as that reproduced in animal models for anti-Ro/SSA binding. The IgG deposition was present in, but not limited to, the conduction system. Scattered small infiltrates of mononuclear cells and a limited, patchy deposition of complement were also observed. These findings support the possibility that isolated congenital heart block may be causally related to autoantibodies.
Collapse
|
174
|
Chu H, Chang YC. Saddle-point excitons in solids and superlattices. PHYSICAL REVIEW. B, CONDENSED MATTER 1987; 36:2946-2949. [PMID: 9943196 DOI: 10.1103/physrevb.36.2946] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/11/2023]
|
175
|
Chu H. [106 cases of chronic gastritis treated mainly by replenishing qi (vital energy) and reducing blood stasis]. ZHONG XI YI JIE HE ZA ZHI = CHINESE JOURNAL OF MODERN DEVELOPMENTS IN TRADITIONAL MEDICINE 1985; 5:267-8, 258. [PMID: 3159493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
|
176
|
Abstract
Distinctive intracytoplasmic tubular complexes have been identified occasionally by electron microscopy in a wide variety of hematologic and nonhematologic disorders. The mechanism of induction and significance of these tubular complexes are unknown. Tubular complexes were identified in the majority of bone marrow lymphoma-leukemia cells in a patient with documented lymphoblastic lymphoma in lymph node. These complexes varied in size but in general ranged from 800--1500 nm, and consisted of masses of nonparallel, twisted, smooth, 40-nm tubules. Continuity with adjacent endoplasmic reticulum was evident in some of the complexes. Cytochemical characteristics of the malignant cells included strong, focal, paranuclear acid phosphatase reactivity and strong, stippled nuclear terminal deoxynucleotidyl transferase positivity. Flow cytometric analysis showed a DNA-RNA content pattern consistent with acute lymphoblastic leukemia and typical of T-cell lymphoma. This represents the first report of such tubular complexes in a presumed T-cell malignancy.
Collapse
|
177
|
Abstract
Distinctive intracytoplasmic tubular complexes have been identified occasionally by electron microscopy in a wide variety of hematologic and nonhematologic disorders. The mechanism of induction and significance of these tubular complexes are unknown. Tubular complexes were identified in the majority of bone marrow lymphoma-leukemia cells in a patient with documented lymphoblastic lymphoma in lymph node. These complexes varied in size but in general ranged from 800--1500 nm, and consisted of masses of nonparallel, twisted, smooth, 40-nm tubules. Continuity with adjacent endoplasmic reticulum was evident in some of the complexes. Cytochemical characteristics of the malignant cells included strong, focal, paranuclear acid phosphatase reactivity and strong, stippled nuclear terminal deoxynucleotidyl transferase positivity. Flow cytometric analysis showed a DNA-RNA content pattern consistent with acute lymphoblastic leukemia and typical of T-cell lymphoma. This represents the first report of such tubular complexes in a presumed T-cell malignancy.
Collapse
|
178
|
Henson JM, Chu H, Irwin CA, Walker JR. Isolation and characterization of dnaX and dnaY temperature-sensitive mutants of Escherichia coli. Genetics 1979; 92:1041-59. [PMID: 391641 PMCID: PMC1214054 DOI: 10.1093/genetics/92.4.1041] [Citation(s) in RCA: 40] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Escherichia coli mutants with temperature-sensitive (ts) mutations in dnaX and dnaY genes have been isolated. Based on transduction by phage P1, dnaX and Y have been mapped at minutes 10.4--10.5 and 12.1, respectively, in the sequence dnaX purE dnaY. Both dna Xts36 and Yts10 are recessive to wild-type alleles present on episomes. F13 carries both dnaX+ and Y+; the shorter F210 carries dnaY+, but not X+. Lambda tranducing phages that carry dnaX+ or Y+ have been isolated, and hybrid plasmids of Col E1 and E. coli DNA from the Clarke and Carbon (1976) collection also carry portions of the dnaX purE dnaY region. Results obtained with the lambda transducing phages and the hybrid plasmids suggest that dnaX is a different gene from the previously characterized dnaZ gene, which is also near minute 10.5--The dnaXts36 mutant, after a shift to 42 degrees, stopped DNA synthesis gradually, and the total amount of DNA increased two-fold. When this mutant was shifted to 44 degrees, the rate of DNA synthesis dropped immediately and the final increment of DNA was only 10% of the initial amount. Replicative DNA synthesis in toluene-treated cells was completely inhibited at 42 degrees and was partially inhibited even at 30 degrees.--When the dnaYts10 mutant was shifted to 42 degrees, DNA synthesis gradually stopped, and the amount of DNA increased 3.6-fold. At 44 degrees, residual DNA synthesis amounted to a two-fold increase. Replicative DNA synthesis in vitro in toluene-treated cells was inactivated after 20 minutes at 42 degrees or by "preincubation" of cells at 42 degrees before toluene treatment.--The dnaX and dnaY products probably function in polymerization of DNA, although participation also in initiation cannot be excluded.
Collapse
|
179
|
Chu H, Klemp A, Stille G. Effects of furosemide and spironolactone on the behavior of morphine-tolerant rats. Psychopharmacology (Berl) 1978; 59:309-10. [PMID: 104336 DOI: 10.1007/bf00426640] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
In morphine-tolerant rats, a reappearance of morphine catalepsy and a disappearance of the turning behavior characteristic of brain-lesioned tolerant animals were observed under the influence of furosemide and spironolactone. The administration of spironolactone together with daily morphine treatment resulted first in an intensification of the morphine symptoms as measured by catalepsy and a retarded appearance of tolerance, typically characterized by a shift from catalepsy to turning movements in animals with single-sided brain lesions. Nontoxic doses of spironolactone raised the sensitivity of morphine-tolerant rats so that previously tolarated morphine doses become lethal.
Collapse
|
180
|
Abstract
Lambda tp mutants, selected for their ability to form turbid plaques on lon hosts, overproduce repressor. The tp1 and tp2 mutations have been located within (or adjacent to) the cIII gene. The tp1 mutation reduced late gene expression, as measured by endolysin synthesis (in the absence of functional cI repressor) and progeny phage yield. The tp4 mutation was mapped in the cY-cII region, and complementation tests indicated that tp4 affects the diffusible product of the cII gene. The tp4 mutation also reduced progeny production, but did not markedly affect endolysin synthesis.
Collapse
|
181
|
Chu H, Malone MM, Haldenwang WG, Walker JR. Physiological effects of growth of an Escherichia coli temperature-sensitive dnaZ mutant at nonpermissive temperatures. J Bacteriol 1977; 132:151-8. [PMID: 334720 PMCID: PMC221839 DOI: 10.1128/jb.132.1.151-158.1977] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The physiological effects of incubation at nonpermissive temperatures of Escherichia coli mutants that carry a temperature-sensitive dnaZ allele [dnaZ(Ts)2016] were examined. The temperature at which the dnaZ(Ts) protein becomes inactivated in vivo was investigated by measurements of deoxyribonucleic acid (DNA) synthesis at temperatures intermediate between permissive and nonpermissive. DNA synthesis inhibition was reversible by reducing the temperature of cultures from 42 to 30 degrees C; DNA synthesis resumed immediately after temperature reduction and occurred even in the presence of chloramphenicol. Inasmuch as DNA synthesis could be resumed in the absence of protein synthesis, we concluded that the protein product of the dnaZ allele (Ts)2016 is renaturable. Cell division, also inhibited by 42 degrees C incubation, resumed after temperature reduction, but the length of time required for resumption depended on the duration of the period at 42 degrees C. Replicative synthesis of cellular DNA, examined in vitro in toluene-permeabilized cells, was temperature sensitive. Excision repair of ultraviolet light-induced DNA lesions was partially inhibited in dnaZ(Ts) cells at 42 degrees C. The dnaZ(+) product participated in the synthesis of both Okazaki piece (8-12S) and high-molecular-weight DNA. During incubation of dnaZ(Ts)(lambda) lysogens at 42 degrees C, prophage induction occurred, and progeny phage were produced during subsequent incubation at 30 degrees C. The temperature sensitivity of both DNA synthesis and cell division in the dnaZ(Ts)2016 mutant was suppressed by high concentrations of sucrose, lactose, or NaCl. Incubation at 42 degrees C was neither mutagenic nor antimutagenic for the dnaZ(Ts) mutant.
Collapse
|
182
|
Chu H, Norris DM, Carlson SD. Ultrastructure of the compound eye of the diploid female beetle, Xyleborus ferrugineus. Cell Tissue Res 1975; 165:23-36. [PMID: 1203972 DOI: 10.1007/bf00222797] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The compound eye of female (diploid) Xyleborus ferrugineus beetles was examined with scanning and transmission electron microscopy. The eye is emarginate, and externally consists of roughly 70-100 facets. Each ommatidium is composed of a thickly biconvex lenslet with about 50 electron dense and rare layers. The lens facet overlies a crystalline cone of the acone type which is roughly hourglass-shaped. Pigment cells envelop the entire ommatidium, and pigment granules also are abundant throughout the cytoplasm of the 8 retinular cells. The rhabdomeres of 2 centrally situated photoreceptor cells effectively fuse into a rhabdom that extends from the base of the crystalline cone deeply into the ommatidium. Six distal peripheral retinular cells encircle the 2 central cells, and their rhabdomeres join laterally to form a rhabdomeric ring around the central rhabdom. The rhabdom and rhabdomeric ring are effectively separated by the cytoplasm of the two central retinular cells which contains the usual organelles and an abundance of shielding pigment granules. Eight axons per ommatidium gather in a tracheae-less fascicle before exiting the eye through the fenestrate basement membrane. No tracheation was observed among the retinular cells. Each Semper cell of each observed crystalline cone contained an abundance of virus-like particles near the cell nucleus. The insect is laboratory reared, and the visual system seems very amenable to photoreceptor investigations.
Collapse
|
183
|
Norris DM, Chu H. Morphology and ultrastructure of the antenna of male Periplaneta americana as related to chemoreception. Cell Tissue Res 1974; 150:1-9. [PMID: 4847086 DOI: 10.1007/bf00220376] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
|
184
|
Chu H, Opitz K. [On the effect of isopropoxamine and butoxamine on respiratory metabolism]. ARCHIVES INTERNATIONALES DE PHARMACODYNAMIE ET DE THERAPIE 1970; 183:224-34. [PMID: 5457463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
|
185
|
Chu H, Tso TC. Fatty Acid composition in tobacco I. Green tobacco plants. PLANT PHYSIOLOGY 1968; 43:428-33. [PMID: 16656780 PMCID: PMC1086856 DOI: 10.1104/pp.43.3.428] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The major fatty acids (16 and 18 carbons) in leaves, flowers, and seeds of Nicotiana tabacum L. cv. Catterton have been analyzed at various intervals during the growth period. From the pattern of their accumulation and relative distribution, it was found that A) the amount of fatty acids in upper young leaves attained a maximum about 75 days after transplanting which is the time of early flowering, while in older leaves the fatty acids continuously declined; B) the relative amount of linolenic acid (18:3) increased progressively with leaf development, from 30% at an early stage to 60% at maturity, while other fatty acids (18:2, 18:1, 18:0, and 16:0) decreased during the same period, indicating a progressive desaturation; and C) a rapid increase of fatty acids was found as flowers developed into seedpods, particularly of linoleic acid (18:2), which comprises 75% of tobacco seed oil.Air-curing resulted in a loss of fatty acids, especially the unsaturated ones.
Collapse
|