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1.
Annu Int Conf IEEE Eng Med Biol Soc ; 2017: 242-245, 2017 Jul.
Article in English | MEDLINE | ID: mdl-29059855

ABSTRACT

The purpose of this study is to verify the impact of a deterioration of the sound quality of voice by a telephone line on estimating Vitality as the extent of depressive tendency based on voice analysis using MIMOSYS. First, the voices of about 1,000 people recorded using a recorder were prepared. Next, each voice was coded and resampled in preparation for transmission over a phone line. Vitalities obtained by analyzing the voices before and after these processes were compared. The results showed high correlation between the Vitality after coding and Vitality before coding, revealing that using a telephone would be an effective way to obtain voices.


Subject(s)
Voice , Humans , Sound , Sound Spectrography , Telephone
2.
Acta Physiol Scand ; 182(2): 133-43, 2004 Oct.
Article in English | MEDLINE | ID: mdl-15450109

ABSTRACT

AIMS: Adenosine is involved in classic pre-conditioning (PC) in most species, acting through especially adenosine A1 and A3 receptors. We studied whether the adenosine A1 receptor (A1R) was important for remote, delayed adaptation to ischaemia using a mouse with targeted deletion of the A1R gene. METHODS: Remote, delayed adaptation was evoked by brain ischaemia (BIPC) through bilateral ligation of the internal carotid arteries. Through microdialysis probes placed in the brain and the abdominal aorta, we found that plasma adenosine increased following carotid artery ligation. Twenty-four hours after ligation, hearts were isolated, Langendorff perfused and subjected to 40 min global ischaemia and 60 min reperfusion. Hearts from sham operated and BIPC animals either with (A1R+/+) or without (A1R-/-) the gene for the adenosine A(1)R were compared with each other. RESULTS: In wild types, BIPC reduced infarct size and improved functional recovery during reperfusion, but BIPC did not protect hearts of A1R-/- mice. There were no significant differences between sham-operated A1R+/+ and A1R-/- in recovery of function or infarct size. The mitogen-activated protein kinases (MAPKs) extracellular signal-regulated protein kinase1/2 (ERK1/2), p38 and c-jun N-terminal kinase (JNK) were phosphorylated during reperfusion of sham treated hearts. The increase in ERK1/2 and p38 phosphorylation detected was attenuated in hearts of BIPC or A1R-/- animals. CONCLUSION: During BIPC adenosine acting on the A1R appears necessary for myocardial protection. MAPK signalling may possibly be involved in organ protection during the delayed phase of remote, delayed adaptation.


Subject(s)
Brain Ischemia/physiopathology , Heart/physiopathology , Receptor, Adenosine A1/physiology , Adaptation, Physiological , Adenosine/metabolism , Animals , Gene Deletion , JNK Mitogen-Activated Protein Kinases/metabolism , Male , Mice , Mice, Knockout , Microdialysis/methods , Mitogen-Activated Protein Kinase 1/metabolism , Mitogen-Activated Protein Kinase 3/metabolism , Myocardial Ischemia/physiopathology , Myocardial Reperfusion/methods , Phosphorylation , Receptor, Adenosine A1/genetics , Ventricular Function, Left/physiology , p38 Mitogen-Activated Protein Kinases/metabolism
3.
Acta Physiol Scand ; 175(4): 279-87, 2002 Aug.
Article in English | MEDLINE | ID: mdl-12167167

ABSTRACT

During the development of a Langendorff preparation of isolated mouse hearts, hitherto undescribed cyclic fluctuations in left ventricular pressure and coronary flow were independently observed in three laboratories. Isolated mouse hearts were perfused with crystalloid glucose-containing Krebs-Hensleit buffer in a constant pressure model, and left ventricular pressures were measured via an intraventricular balloon catheter. After acquiring technical skill in preparing the mouse hearts, the perfusionists observed that fluctuations in cardiac performance with a cycle period lasting 5-10 min occurred shortly after initiation of perfusion. Each fluctuation cycle consisted of a phase of increase and a phase of decrease. Synchronized with the fluctuations in left ventricular pressure, increases and decreases in dP/dt max took place. Analogous fluctuations in coronary flow occurred, with onset 1-2 min later than changes in left ventricular systolic pressure. In some preparations a gradual ST-segment elevation was seen on the electrocardiogram during the systolic pressure increase phase. The amplitude of the fluctuations could be augmented by increasing the perfusion pressure, and reduced, but not abolished, by lowering the pressure. Changes in buffer calcium, magnesium, or sodium concentration did not alter the fluctuations, nor did any change of anaesthetics, mouse strain, or left ventricular drainage. Altering the perfusion mode from constant pressure to constant flow did not prevent the occurrence of the cyclic fluctuations. The hearts became stable and the fluctuations disappeared when the buffer was supplemented with 2 mm pyruvate. In the present study, pyruvate given throughout stabilization and reperfusion also markedly attenuated the ischaemic insult, as evidenced by the delayed ischaemic contracture and a reduced magnitude of ischaemic contracture. A cardioprotective effect was only visible at early reperfusion, did not affect the final functional recovery. In conclusion, a phenomenon of cyclic fluctuations in left ventricular pressure followed by fluctuations in coronary flow was observed in isolated mouse hearts. These could be abolished by adding 2 mm pyruvate to the perfusion buffer. Pyruvate in the buffer also markedly attenuated the post-ischaemic deterioration of cardiac performance seen in this mouse model.


Subject(s)
Myocardial Contraction/physiology , Pyruvic Acid/pharmacology , Animals , Blood Pressure/drug effects , Blood Pressure/physiology , Calcium/analysis , Electrocardiography/methods , Female , Magnesium/analysis , Male , Mice , Mice, Inbred BALB C , Mice, Inbred C57BL , Myocardial Contraction/drug effects , Myocardial Reperfusion Injury/physiopathology , Pentobarbital/pharmacology , Perfusion , Sodium/analysis , Ventricular Function
4.
Life Sci ; 69(17): 2067-80, 2001 Sep 14.
Article in English | MEDLINE | ID: mdl-11589521

ABSTRACT

Nitric oxide (NO) may play an essential role for maintenance of cardiac function and perfusion, while endothelial dysfunction of atherosclerotic vessels may aggravate ischaemia/reperfusion injury. This paper investigates the role of nitric oxide in ischaemia/reperfusion injury in hearts with coronary atherosclerosis. Hearts of apolipoprotein E/LDL receptor double knockout (ApoE/LDLr KO) mice fed an atherogenic diet for 7-9 months were isolated and Langendorff-perfused with 40 minutes of global ischaemia and 60 minutes reperfusion, and funtion and infarction compared with hearts of C57BL/6 controls in the prescence or abscence of the NO-donor SNAP or the NOS inhibitor L-NAME. Hearts of animals with atherosclerosis were more susceptible to ischaemia/reperfusion injury than hearts of animals with healthy vessels, evident as more impaired left ventricular performance. SNAP protected function and reduced infarct size in atherosclerotic hearts, but the same concentration of SNAP was detrimental in normal hearts, perhaps due to NO-overproduction and peroxynitrite formation demonstrated immunohistochemically as increased formation of nitrosylated tyrosine. A low concentration of SNAP protected against ischaemia/reperfusion dysfunction in normal hearts. L-NAME decreased left ventricular performance in atherosclerotic hearts. These findings suggest that impaired endothelium dependent function contributes to reperfusion injury in coronary atherosclerosis.


Subject(s)
Arteriosclerosis/physiopathology , Nitric Oxide/physiology , Reperfusion Injury/physiopathology , Animals , Apolipoproteins E/genetics , Arrhythmias, Cardiac/physiopathology , Arteriosclerosis/enzymology , Arteriosclerosis/metabolism , Blotting, Western , Immunohistochemistry , In Vitro Techniques , Mice , Mice, Inbred C57BL , Mice, Knockout , NG-Nitroarginine Methyl Ester/pharmacology , Nitric Oxide Donors/pharmacology , Nitric Oxide Synthase/metabolism , Nitric Oxide Synthase Type II , Nitric Oxide Synthase Type III , Penicillamine/analogs & derivatives , Penicillamine/pharmacology , Receptors, LDL/genetics , Reperfusion Injury/enzymology , Reperfusion Injury/metabolism , Troponin T/metabolism
5.
Ann Thorac Surg ; 71(4): 1296-303; discussion 1303-4, 2001 Apr.
Article in English | MEDLINE | ID: mdl-11308177

ABSTRACT

BACKGROUND: Coronary atherosclerosis has profound effects on vascular and myocardial biology, and it has been speculated that the atherosclerotic heart does not benefit from ischemic preconditioning. METHODS: To investigate if atherosclerosis would influence the preconditioning response, Apolipoprotein E/low density lipoprotein (LDL) receptor double knockout mice (ApoE/LDLr-/-) were fed an atherogenic diet (21% fat, 0.15% cholesterol) for 6 to 8 months. At that time, extensive atherosclerotic lesions throughout the coronary tree were seen in transverse sections stained with Oil Red-O. Hearts of ApoE/LDLr-/- mice were Langendorff-perfused with 40 minutes of global ischemia and 60 minutes reperfusion, and compared with C57BL/6 controls. Preconditioning with two episodes of 2 minutes of ischemia and 5 minutes reperfusion, or exposing the mice to a hyperoxic environment (O2 > 98%) for 60 minutes before heart perfusion, was performed. RESULTS: Hearts of mice with coronary atherosclerosis had worse postischemic function, and increased infarct size and troponin T release compared to hearts of C57BL/6 mice. Ischemic preconditioning improved postischemic ventricular function, and reduced myocardial infarct size and troponin T release in both normal and ApoE/LDLr-/- mice. The effects were most pronounced in ApoE/LDLr-/- hearts. Exposure to hyperoxia exerted a similar protection of function and cell viability of ApoE/LDLr-/- mice hearts. CONCLUSIONS: These findings suggest that the severely atherosclerotic heart may be protected by preconditioning induced by ischemia or hyperoxia.


Subject(s)
Coronary Artery Disease/therapy , Diet, Atherogenic , Ischemic Preconditioning, Myocardial/methods , Myocardial Infarction/prevention & control , Analysis of Variance , Animals , Coronary Artery Disease/pathology , Disease Models, Animal , Female , Heart Function Tests , Hyperoxia , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Myocardial Infarction/pathology , Probability , Reference Values , Sensitivity and Specificity , Severity of Illness Index , Troponin T/analysis
6.
Br J Pharmacol ; 131(7): 1255-61, 2000 Dec.
Article in English | MEDLINE | ID: mdl-11090096

ABSTRACT

1. Mice lacking the apolipoprotein E and low density lipoprotein receptor genes (E degrees xLDLR degrees ) develop atherosclerosis and endothelial dysfunction. The aim of this study was to characterize the roles of L-arginine and tetrahydrobiopterin (BH(4)) for endothelium-dependent relaxation and the changes in the vasoconstrictor response to endothelin-1 (ET-1) in thoracic aortic rings of E degrees xLDLR degrees mice. 2. Histological examination revealed severe atherosclerosis of the thoracic aorta of E degrees xLDLR degrees mice. Relaxations induced by acetylcholine (Ach), but not that to sodium nitroprusside, were significantly impaired in E degrees xLDLR degrees mice compared to control mice indicating attenuated endothelium-dependent relaxations. 3. Preincubation with the nitric oxide (NO) substrate L-arginine did not affect, whereas the co-factor for NO synthase, BH(4), slightly improved the relaxations induced by Ach. Combined preincubation with L-arginine and BH(4) induced a pronounced enhancement of Ach-induced relaxations in E degrees xLDLR degrees mice. The relaxations induced by Ach in E degrees xLDLR degrees mice in the presence of L-arginine and BH(4) were not different from those observed in control mice. 4. Preincubation with superoxide dismutase did not affect Ach-induced relaxations in aorta from E degrees xLDLR degrees mice. 5. The contractile response to ET-1 was enhanced in E degrees xLDLR degrees mouse aorta. The contractions were abolished by the ET(A) receptor antagonist LU 135252. The ET(B) receptor agonist sarafotoxin 6c did not induce contractions or relaxations. 6. It is concluded that endothelial dysfunction of E degrees xLDLR degrees mouse aorta is reversed by combined administration of L-arginine and BH(4). In addition, the ET(A) receptor-mediated vasoconstriction by ET-1 is enhanced in E degrees xLDLR degrees mice.


Subject(s)
Arteriosclerosis/physiopathology , Biopterins/analogs & derivatives , Endothelium, Vascular/physiopathology , Acetylcholine/pharmacology , Animals , Arginine/administration & dosage , Arteriosclerosis/pathology , Biopterins/administration & dosage , Dietary Supplements , Dose-Response Relationship, Drug , Endothelins/pharmacology , Endothelium, Vascular/drug effects , Mice , Mice, Inbred C57BL , Nitroprusside/pharmacology , Superoxide Dismutase/pharmacology , Vasoconstriction/drug effects , Vasodilation/drug effects
7.
Nihon Kyobu Geka Gakkai Zasshi ; 43(7): 1039-43, 1995 Jul.
Article in Japanese | MEDLINE | ID: mdl-7561316

ABSTRACT

A 47-year-old male with pseudoaneurysm of the left ventricle secondary to mitral valve replacement was herein reported because of its unique etiology. The pseudoaneurysm was presumably resulted from the mitral valve dilator wound at the apex of the left ventricle, which was produced by closed mitral commissurotomy 23 years ago. To our knowledge, it seems to be a rare reported case with pseudoaneurysm of the left ventricle caused by closed transventricular mitral commissurotomy.


Subject(s)
Aneurysm, False/surgery , Catheterization , Heart Aneurysm/surgery , Heart Valve Prosthesis , Mitral Valve Stenosis/therapy , Aneurysm, False/etiology , Heart Aneurysm/etiology , Heart Ventricles/surgery , Humans , Male , Middle Aged , Mitral Valve/surgery
8.
Surg Today ; 25(4): 373-7, 1995.
Article in English | MEDLINE | ID: mdl-7633132

ABSTRACT

We report herein the case of a 22-year-old man with a history of Kawasaki disease who developed a giant calcified aneurysm of the left main coronary artery. The aneurysm was successfully resected and coronary bypass surgery was performed using the bilateral internal thoracic arteries. The resected aneurysm, the maximal diameter of which was 27 mm, showed heavy calcification of the inner layer and extended into the adjacent coronary arteries, producing a significant narrowing of the lumen of both the left main trunk (50%) and the anterior descending branch (50%). Extensive intimal calcification presumably prevented normal luminal development and produced a significant narrowing as the patient grew into adulthood. A cause for stenotic lesions developing in the coronary artery adjacent to a coronary aneurysm in adults with a history of Kawasaki disease is suggested here by the resected aneurysm seen in this patient. Thus, adult patients with giant coronary artery aneurysms and significant stenotic lesions of the coronary artery associated with Kawasaki disease may require aneurysmectomy in addition to bypass surgery.


Subject(s)
Coronary Aneurysm/surgery , Coronary Artery Bypass , Coronary Vessels/surgery , Mucocutaneous Lymph Node Syndrome/complications , Adult , Coronary Aneurysm/etiology , Coronary Aneurysm/pathology , Coronary Angiography , Coronary Vessels/pathology , Humans , Male
9.
Cancer Res ; 39(10): 4064-8, 1979 Oct.
Article in English | MEDLINE | ID: mdl-225015

ABSTRACT

The role of DNA repair in transformation was investigated by infecting repair-deficient xeroderma pigmentosum (XP) variant cells, XP variant heterozygous cells, and normal human fibroblasts with simian virus 40 which had been irradiated by ultraviolet light. The transformation frequencies obtained were compared to those observed for unirradiated virus. While normal and heterozygous cells showed no differences between transformation frequencies using either irradiated or untreated virus, two XP variant cell lines were transformed 2- to 7-fold more readily with irradiated virus than with unirradiated virus. XP variant cells were also found to produce lower than normal quantities of virus following infection with either damages or undamaged virus, suggesting that increased viral production was not contributing to the increased transformation seen for these cells. Finally, the proportion of cells which repair ultraviolet light-irradiated simian virus 40 was found to be similar for wild-type and XP variant cells, suggesting that enhanced transformation in the mutant cells was not associated with a reduction in the numbers of cells which repair damaged virus. Several possible mechanisms to account for the increased transformation of XP variant cells by ultraviolet light-irradiated simian virus 40 are proposed.


Subject(s)
Cell Transformation, Neoplastic , Cell Transformation, Viral , DNA Repair , Xeroderma Pigmentosum/metabolism , Cell Line , Humans , Mutation , Simian virus 40/radiation effects , Ultraviolet Rays , Xeroderma Pigmentosum/genetics
10.
Mol Gen Genet ; 153(2): 205-10, 1977 Jun 08.
Article in English | MEDLINE | ID: mdl-329118

ABSTRACT

The product of phage P22 gene c1 has two functions: (1) it promotes synthesis of repressor and (2) during the first minutes of infection it retards expression of some lytic genes. We call the second, negative function "c1 retardation". We investigated c1 retardation in a mutant host of Salmonella typhimurium that is resistant to rifampicin and carries an altered RNA polymerase. No c1 retardation of DNA synthesis was detectable in this host after infection with wild-type phages. This elimination of the normally detectable c1 function leads to the conclusion that the mutant RNA polymerase interferes with the expression of c1 gene activity. Wild-type genes form clear plaques on the mutant host. Mutants of P22 called cly were isolated by others. These mutants form turbid plaques on the altered RNA polymerase host. Infections with P22 cly in the mutant host resulted in detectable c1 retardation. The cly mutation therefore restores c1 activity in a host which wild-type c1 is not expressed. Two spontaneous mutants were isolated from the mutant host. These two strains allowed partial expression of c1 retardation, although they remained rifampicin resistant. We interpret our data to indicate that expression of the normal functions of the gene c1 product requires an interaction of that product with the host RNA polymerase.


Subject(s)
DNA-Directed RNA Polymerases/pharmacology , Genes , Mutation , Salmonella Phages/ultrastructure , Drug Resistance, Microbial , Lysogeny , RNA, Bacterial/biosynthesis , Rifampin/pharmacology , Salmonella typhimurium/drug effects , Salmonella typhimurium/enzymology
11.
J Virol ; 21(3): 956-64, 1977 Mar.
Article in English | MEDLINE | ID: mdl-321806

ABSTRACT

A rifampin-resistant mutant of Salmonella typhimurium carries an altered RNA polymerase. Wild-type (c+) phage P22 displays clear plaques and a reduced lysogenization frequency on this mutant host. The cly mutants of P22 were isolated on the basis of their ability to lysogenize such mutant hosts. Two classes of regulatory events, both of which are dependent on P22 gene c1 activity, are necessary for the establishment of lysogeny in P22. The positive events culminate in repressor synthesis; the negative events cause a retardation in phage DNA synthesis. Neither the positive nor the negative events are observed in P22c+ infections of the mutant host. Both effects are found in P22cly infections of the mutant host. Observable results of both the negative and the positive events are exaggerated in P22cly infections of wild-type hosts as compared to P22c+ infections. The cly mutation apparently increases the positive and negative regulatory events so that they are detectable in the mutant host and exaggerated in wild-type hosts. Possible mechanisms that result in the high frequency of lysogenization that characterizes the cly mutation and the nature of the cly mutation are discussed.


Subject(s)
DNA, Viral/biosynthesis , Genes, Regulator , Salmonella Phages/metabolism , Salmonella typhimurium , Drug Resistance, Microbial , Lysogeny , Molecular Biology , Mutation , Rifampin/pharmacology , Salmonella typhimurium/drug effects
12.
J Virol ; 18(1): 65-70, 1976 Apr.
Article in English | MEDLINE | ID: mdl-768525

ABSTRACT

The product of phage P22 gene c1 has two functions: it promotes synthesis of P22 repressor and it retards expression of some lytic genes. We present evidence that this product is inactivated in UV-irradiated hosts. The conditions for inactivation of c1 product include a functional DNA recombination system involving the host recA gene.


Subject(s)
Bacterial Proteins/radiation effects , Genes , Salmonella Phages/radiation effects , Salmonella typhimurium/radiation effects , Ultraviolet Rays , DNA, Viral/biosynthesis , Genes, Regulator , Mutation , Radiation Effects , Salmonella Phages/growth & development , Salmonella Phages/metabolism , Virus Replication
13.
Mol Gen Genet ; 144(2): 199-204, 1976 Mar 22.
Article in English | MEDLINE | ID: mdl-775292

ABSTRACT

Phage P22 mutation c27 defines a site required for establishment , but not maintenance of repressor synthesis. This study confirms that P22 c27 is able to synthesize repressor if active repressor is present. An interaction involving gene products of c1 and c3 and the site c27 retards expression of the lytic genes of P22. Mutations in gene c1 eliminate the retardation of lytic gene expression, but c27 does not alleviate the retardation. These results are used to construct a model that postulates that binding of c1 and c3 products to DNA at or near c27 is sufficient to cause retardation of lytic gene expression. The functioning of c27 is contrasted to that of the analogous cy mutants of lambda. The effect of the c27 mutation upon alleviation of "cl repression" was studied in a partial revertant of Salmonella typhimurium Pox-1 in which c1 repression is exaggerated. The higher frequency of lysogenization seen in the mutant host is related to enhanced cl repression.


Subject(s)
Genes, Regulator , Lysogeny , Mutation , Salmonella Phages , Salmonella typhimurium , Base Sequence , Chromosome Mapping , DNA, Viral
14.
J Virol ; 16(5): 1184-90, 1975 Nov.
Article in English | MEDLINE | ID: mdl-171449

ABSTRACT

A Polymyxin B-sensitive mutant of Salmonella typhimurium (Pox-1) channels all infecting wild-type P22 toward lysogenization. The efficiency of this channeling is sufficiently high that P22c+ (wild type) cannot form plaques on Pox-1; phage mutants defective in repressor synthesis (P22c1, c2, c3) or refractory toward repressor (P22vir B) can form plaques. The lytic growth of all phages which have a functional c1 gene is retarded in Pox-1; this retardation is seen even in phages which cannot make repressor. We present experiments which are consistent with the explanation that the retardation is an exaggeration of a normal regulatory event. In a wild-type host, P22 genes c1 and c3 products, host RNA polymerase, and other host factors (?) interact at a promotor site (c27) IN THE PHAGE DNA. This interaction promotes repressor synthesis and represses transcription of lytic genes. In the mutant Pox-1, a host product involved in viral DNA synthesis and transcription is altered. The altered host product results in stronger retardation of lytic gene transcription. The importance of this interaction in the decision between lysis and lysogeny is discussed. The mutant Pox-1 alters the expression or activity of another phage gene. Gene c3 product is absolutely required for lysogenization in this host, although it is not so required in wild-type S. typhimurium.


Subject(s)
Bacteriolysis , Genes , Lysogeny , Salmonella Phages/growth & development , Salmonella typhimurium , Drug Resistance, Microbial , Genes, Regulator , Models, Biological , Mutation , Polymyxins/pharmacology , Salmonella Phages/metabolism , Salmonella typhimurium/drug effects , Viral Proteins/biosynthesis
15.
Mol Gen Genet ; 138(1): 71-9, 1975.
Article in English | MEDLINE | ID: mdl-1102926

ABSTRACT

Mutants of P22 which have been located in the c2 repressor gene were examined. The most rightward "c2 mutation" was found to define a site that is necessary only for the establishment and not for the maintenance of repressor synthesis. We conclude that this site c27 is an analog of cy mutants in phage lambda which define a promotor for repression establishment (pre). The K5 mutation of P22 maps between c27 and all other c2 mutants. Examination of its biological behavior and direct measurement of repressor activity show that K5 does not affect c2 repression. A model to explain these findings implies that c27 and K5 affect transcripts of opposite directions. P22 c1 mutants do not allow c2 repressor synthesis and we conclude that the activity of c1 product (and presumably c3 product) at the site defined by c27 is necessary for repressor synthesis. The combined activity of c1 and c3 product at c27 is postulated to promote repressor synthesis and block transcription of vegatative phage genes to the right of K5. After repressor synthesis has been established, another site analogous to lambda prm is sufficient for repressor synthesis and c27 is no longer required. These observations and conclusions point to a very close analogy between repressor synthesis and control in phages P22 and lambda.


Subject(s)
Carrier Proteins/analysis , Coliphages , Genes, Regulator , Mutation , Salmonella Phages , Salmonella typhimurium , DNA/analysis , Genotype , Lysogeny
16.
J Bacteriol ; 119(2): 508-13, 1974 Aug.
Article in English | MEDLINE | ID: mdl-4368944

ABSTRACT

A slowly growing, polymyxin-sensitive mutant of Salmonella typhimurium was isolated. Wild-type phage P22 form plaques on the mutant at 5 x 10(-4), the frequency observed on wild-type hosts. All P22 clear mutants form plaques with near normal frequency. The inability of the mutant to form plaques is correlated with an increase in lysogenization frequency. The cause of the increased lysogenization frequency is not known, but it is not the result of overproduction of cyclic adenosine 5'-monophosphate.


Subject(s)
Lysogeny , Mutation , Salmonella Phages/growth & development , Salmonella typhimurium/growth & development , Cyclic AMP/biosynthesis , Drug Resistance, Microbial , Mutagens , Nitrosoguanidines , Polymyxins/pharmacology , Salmonella typhimurium/drug effects , Salmonella typhimurium/metabolism
17.
J Virol ; 6(3): 286-94, 1970 Sep.
Article in English | MEDLINE | ID: mdl-4320387

ABSTRACT

A temperature-sensitive simian virus 40 (SV40) mutant, tsTNG-1, has been isolated from nitrosoguanidine-treated and SV40-infected African green monkey kidney (CV-1) cultures. Replication of virus at the nonpermissive temperature (38.7 C) was 3,000-fold less than at the permissive temperature (33.5 C). Plaque formation by SV40tsTNG-1 deoxyribonucleic acid (DNA) on CV-1 monolayers occurred normally at 33.5 C but was grossly inhibited at 38.7 C. The time at which virus replication was blocked at 38.7 C was determined by temperature-shift experiments. In shift-up experiments, cultures infected for various times at 33.5 C were shifted to 38.7 C. In shift-down experiments, cultures infected for various times at 38.7 C were shifted to 33.5 C. All cultures were harvested at 96 hr postinfection (PI). No virus growth occurred when the shift-up occurred before 40 hr PI. Maximum virus yields were obtained at 96 hr PI when the shift-down occurred at 66 hr, but only about 15% of the maximum yield was obtained when the shift-down occurred at 76 hr PI. These results indicate that SV40tsTNG-1 contains a conditional lethal mutation in a late viral gene function. Mutant SV40tsTNG-1 synthesized T antigen, viral capsid antigens, and viral DNA, and induced thymidine kinase activity at either 33.5 or 38.7 C. The properties of the SV40 DNA synthesized in mutant-infected CV-1 cells at 33.5 or 38.7 C were very similar to those of SV40 DNA made in parental virus-infected cells, as determined by nitrocellulose column chromatography, cesium-chloride-ethidium bromide equilibrium centrifugation, and by velocity centrifugation in neutral sucrose gradients. Mutant SV40tsTNG-1 enhanced cellular DNA synthesis in primary cultures of mouse kidney cells at 33.5 and 38.7 C and also transformed mouse kidney cultures at 36.5 C. SV40tsTNG-1 was recovered from clonal lines of transformed cells after fusion with susceptible CV-1 cells and incubation of heterokaryons at 33.5 C, but not at 38.7 C.


Subject(s)
Mutation , Simian virus 40/growth & development , Temperature , Virus Replication , Animals , Cell Line , Centrifugation, Density Gradient , Complement Fixation Tests , Culture Techniques , DNA, Viral/biosynthesis , Fluorescent Antibody Technique , Haplorhini , Kidney , Mice , Parainfluenza Virus 1, Human , Simian virus 40/enzymology , Simian virus 40/immunology , Thymidine Kinase/metabolism , Transformation, Genetic , Tritium
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