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1.
Eur J Surg Oncol ; 42(10): 1576-83, 2016 Oct.
Article in English | MEDLINE | ID: mdl-27378158

ABSTRACT

BACKGROUND: Hepatocellular cancer (HCC) is a leading cause of mortality worldwide. Liver resection or transplantation offer the best chance of long-term survival. The aim of this study was to perform a survival and prognostic factor analysis on patients who underwent resection of HCC at two major tertiary referral hospitals, and to investigate a pre-operative prediction model for microvascular invasion (MVI). METHODS: Clinico-pathological and survival data were collected from all patients who underwent liver resection for HCC at two tertiary referral centres (Royal North Shore/North Shore Private Hospitals and Westmead Hospital) from 1998 to 2012. An overall and disease-free survival analysis was performed and a predictive model for MVI identified. RESULTS: The total number of patients in this series was 125 and the 5-year overall and disease-free survival rates were 56% and 37%, respectively. MVI was the only factor to be independently associated with a poor prognosis on both overall and disease-free survival. Age ≥64 years, a serum alpha-fetoprotein (AFP) ≥400 ng/ml (×40 above normal) and tumor size ≥50 mm were independently associated with MVI. An MVI prediction model using these three pre-operative factors provides a good assessment of the risk of MVI. CONCLUSION: MVI in the resected specimen of patients with HCC is associated with a poor prognosis. A preoperative MVI prediction model offers a useful way to identify patients at risk of relapse. However, more precise predictive models using molecular and genetic variables are needed to improve selection of patients most suitable for radical surgical treatment.


Subject(s)
Carcinoma, Hepatocellular/surgery , Hepatectomy , Liver Neoplasms/surgery , Aged , Carcinoma, Hepatocellular/mortality , Carcinoma, Hepatocellular/pathology , Female , Humans , Liver Neoplasms/mortality , Liver Neoplasms/pathology , Male , Microvessels/pathology , Middle Aged , Neoplasm Invasiveness , Retrospective Studies , Treatment Outcome
2.
Theriogenology ; 67(1): 178-84, 2007 Jan 01.
Article in English | MEDLINE | ID: mdl-17109945

ABSTRACT

This study compares the meat composition of the offspring from boars produced by somatic cell nuclear transfer (n=4) to that of the offspring from conventionally produced boars (n=3). In total, 89 commercial gilts were artificially inseminated and 61 progressed to term and farrowed. All of the resulting piglets were housed and raised identically under standard commercial settings and slaughtered upon reaching market weight. Loin samples were taken from each slaughtered animal and shipped offsite for meat composition analysis. In total, loin samples from 404 animals (242 from offspring of clones and 162 from controls) were analyzed for 58 different parameters generating 14,036 and 9396 data points from offspring of clones and the controls, respectively. Values for controls were used to establish a range for each parameter. Ten percent was then added to the maximum and subtracted from the minimum of the control range, and all results within this range were considered clinically irrelevant. Of the 14,036 data points from the offspring of clones, only three points were found outside the clinically irrelevant range, two of which were within the range established by the USDA National Nutrient Database for Standard Reference, Release 18, 2005; website: (www.nal.usda.gov/fnic/foodcomp/search/). The only outlier was the presence of Eicosadienoic acid (C20:2) in one sample which is typically present in minute quantities in pork; no reference data were found regarding this fatty acid in the USDA National Nutrient Database. In conclusion, these data indicated that meat from the offspring of clones was not chemically different than meat from controls and therefore supported the case for the safety of meat from the offspring of clones.


Subject(s)
Cloning, Organism/veterinary , Consumer Product Safety , Meat/analysis , Nuclear Transfer Techniques/veterinary , Swine/genetics , Animal Husbandry/methods , Animals , Case-Control Studies , Female , Male , Swine/physiology
3.
Cloning Stem Cells ; 8(3): 130-9, 2006.
Article in English | MEDLINE | ID: mdl-17009889

ABSTRACT

This study compares the reproductive performance of boars produced by somatic cell nuclear transfer versus conventional breeding. Two different genotypes were selected for comparison: terminal cross line 1 (TX1) and terminal cross line 2 (TX2). The boars selected for comparison from TX1 were three cloned boars, produced by somatic cell nuclear transfer and the conventionally produced progenitor of the clones. The boars selected for comparison from TX2 were a cloned boar produced by somatic cell nuclear transfer and two conventionally produced half sibling boars that were offspring of the progenitor of the clone. Semen from each boar was collected, extended, evaluated and shipped offsite. Upon arrival, the semen was reevaluated and utilized for artificial insemination of 89 commercial gilts, at least 12 gilts per boar, producing 625 piglets. Pregnancy rates were determined at day 30 and 110 of gestation; and farrowing rate and gestation length were recorded. Differences were observed in some of the semen characteristics analyzed with the clones usually possessing superior semen quality to the control, this likely being a result of age differences amongst the clones and controls. Additionally no differences were noted between the clones and controls (progenitor) or between individual boars within genetic line for pregnancy rates, gestation length or any of the litter parameters examined between the clones and controls. These data further support previous reports with limited numbers that the reproductive capabilities of cloned boars are equal to that of conventionally produced boars.


Subject(s)
Cloning, Organism/veterinary , Sus scrofa/physiology , Animals , Breeding , Cloning, Organism/methods , Female , Fertility/physiology , Insemination, Artificial/veterinary , Male , Nuclear Transfer Techniques , Pregnancy , Reproduction/physiology
4.
Bioconjug Chem ; 12(1): 84-91, 2001.
Article in English | MEDLINE | ID: mdl-11170370

ABSTRACT

This report describes the synthesis of two DTPA-conjugated cyclic peptides, cyclo(Arg-Gly-Asp-D-Phe-Lys)DTPA (SQ169) and [cyclo(Arg-Gly-Asp-D-Phe-Lys)](2)DTPA (SQ170), and a chromatographic study of their (90)Y complexes (RP762 and RP763, respectively). The goal is to study the solution structure and the possible isomerism of (90)Y-labeled DTPA-biomolecule conjugates at the tracer level (approximately 10(-10) M). RP762 was prepared in high radiochemical purity (RCP > 95%) by reacting 2 microg of SQ169 with 20 mCi of (90)YCl(3) (corresponding to a SQ169:Y ratio of approximately 4:1) in the 0.5 M ammonium acetate buffer (pH 8.0) at room temperature. RP763 was prepared in a similar fashion using SQ170. In both cases, the (90)Y-chelation was instantaneous. By a reversed-phase HPLC method, it was found that RP762 exists in solution as a mixture of two detectable isomers (most likely cis and trans isomers), which interconvert at room temperature. The interconversion of different isomeric forms of RP762 involves a rapid exchange of "wrapping isomers" via the "wagging" of the diethylenetriamine backbone, "shuffling" of the two NO(2) donor sets, and inversion at the ternimal amine-nitrogen atom. The inversion at a terminal nitrogen atom requires simultaneous dissociation of the NO(2) donor set. For RP763, the interconversion of different isomers is much faster than that for RP762 due to the weak bonding of two carbonyl-oxygen donors. Therefore, RP763 shows only one broad radiometric peak in its HPLC chromatogram. The rapid interconversion of different isomers is intramolecular via a partial dissociative mechanism. The results obtained in this study are consistent with the lack of kinetic inertness of (90)Y- and (111)In-labeled DTPA-biomolecule conjugates. Thus, the design of new BFCs should be focused on those which form lanthanide complexes with high thermodynamic stability and more importantly kinetic inertness.


Subject(s)
Organometallic Compounds/chemistry , Peptides, Cyclic/chemistry , Radiopharmaceuticals/chemistry , Yttrium , Chemical Phenomena , Chemistry, Physical , Chromatography, High Pressure Liquid , Isomerism , Molecular Conformation , Organometallic Compounds/chemical synthesis , Peptides, Cyclic/chemical synthesis , Radiopharmaceuticals/chemical synthesis , Solutions , Yttrium Radioisotopes
5.
J Eukaryot Microbiol ; 48(2): 147-60, 2001.
Article in English | MEDLINE | ID: mdl-12095102

ABSTRACT

This study asks two questions: 1) whether Hsp90 is involved in the regulation of cortical patterning in Tetrahymena, and 2) if it is, whether specific defects in this regulation can be attributed to functional insufficiency of the Hsp90 molecule. To address question 1, we compared the effects of a specific inhibitor of Hsp90, geldanamycin, on population growth and on development of the oral apparatus in two Tetrahymena species, T. pyriformis and T. thermophila. We observed that geldanamycin inhibits population growth in both species at very low concentrations, and that it has far more severe effects on oral patterning in T. pyriformis than in T. thermophila. These effects are parallel to those of high temperature in the same two species, and provide a tentative affirmative answer to the first question. To address question 2, we ascertained the base sequence of the genes that encode the Hsp90 molecules which are induced at high temperatures in both Tetrahymena species, as well as corresponding sequences in Paramecium tetraurelia. Extensive comparative analyses of the deduced amino acid sequences of the Hsp90 molecules of the two Tetrahymena species indicate that on the basis of what we currently know about Hsp90 both proteins are equally likely to be functional. Phylogenetic analyses of Hsp90 amino acid sequences indicate that the two Tetrahymena Hsp90 molecules have undergone a similar number of amino acid substitutions from their most recent common ancestor, with none of these corresponding to any known functionally critical region of the molecule. Thus there is no evidence that the Hsp90 molecule of T. pyriformis is functionally impaired; the flaw in the control of cortical patterning is more likely to be caused by defects in mechanism(s) that mediate the response to Hsp90, as would be expected from the "Hsp90 capacitor" model of Rutherford and Lindquist.


Subject(s)
HSP90 Heat-Shock Proteins/physiology , Tetrahymena pyriformis/growth & development , Tetrahymena thermophila/growth & development , Amino Acid Sequence , Animals , Benzoquinones , Cloning, Molecular , HSP90 Heat-Shock Proteins/chemistry , HSP90 Heat-Shock Proteins/genetics , Lactams, Macrocyclic , Molecular Sequence Data , Morphogenesis , Paramecium/genetics , Phylogeny , Quinones/pharmacology , Sequence Alignment , Temperature , Tetrahymena pyriformis/drug effects , Tetrahymena pyriformis/genetics , Tetrahymena pyriformis/physiology , Tetrahymena thermophila/drug effects , Tetrahymena thermophila/genetics , Tetrahymena thermophila/physiology
8.
Eur J Anaesthesiol ; 16(11): 796-8, 1999 Nov.
Article in English | MEDLINE | ID: mdl-10713875

ABSTRACT

An 86-year-old man on whom a transurethral resection of prostate was performed under spinal anaesthesia developed profound bradycardia and hypotension with disturbance of consciousness during transfer to the recovery room. Initial treatment with atropine produced rapid improvement in cardiovascular and cerebral function. A further hypotensive episode (without bradycardia) occurred approximately 1 h later but responded rapidly to methoxamine. The patient made a full recovery during an overnight stay on the High Dependency Unit. Possible mechanisms for this event are discussed, with the proposal that the concomitant administration of captopril and the relative unavailability of Angiotensin II may have significantly contributed to the problem.


Subject(s)
Anesthesia, Spinal/adverse effects , Angiotensin-Converting Enzyme Inhibitors/adverse effects , Bradycardia/chemically induced , Captopril/adverse effects , Hypotension/chemically induced , Adenocarcinoma/surgery , Aged , Aged, 80 and over , Drug Interactions , Humans , Male , Prostatic Neoplasms/surgery , Transurethral Resection of Prostate
9.
Biochem Pharmacol ; 55(10): 1573-84, 1998 May 15.
Article in English | MEDLINE | ID: mdl-9633993

ABSTRACT

In this study, we have compared the uptake of L-cysteine (L-CySH), D-cysteine (D-CySH), L-cysteine isopropyl ester (L-CIPE) and D-cysteine isopropyl ester (D-CIPE) in rat lung slices and tracheal sections and determined the effectiveness of glutathione (GSH), GSH isopropyl monoester, GSH isopropyl diester, gamma-glutamylcysteine (gamma-glu-cys) isopropyl monoester and gamma-glu-cys isopropyl diester to elevate and prolong intracellular GSH concentrations in rat lung slices. Lung slices were incubated with 1.0 mM of thiol and the concentrations determined intracellularly and extracellularly with time. Slices incubated with GSH, GSH isopropyl diester and gamma-glu-cys isopropyl diester had cellular GSH concentrations increased by up to 60%, 95% and 58%, respectively, whereas GSH isopropyl monoester and gamma-glu-cys isopropyl monoester did not increase the intracellular GSH concentration. Extracellularly, the GSH concentration had decreased by 15%, GSH isopropyl diester by 27%, gamma-glu-cys isopropyl diester by 66% and both isopropyl monoesters by over 90% at 120 min. Lung slices and tracheal sections incubated with L- or D-CySH at 37 degrees had increased cellular concentrations of L- and D-CySH which ranged between 0.88-1.25 nmol mg(-1) and 1.35-2.25 nmol mg(-1) , respectively. Reducing the incubation temperature to 4 degrees had little effect on the accumulation of D-CySH; however, L-CySH concentrations increased progressively in the trachea and lung to reach 2.73 and 2.63 nmol mg(-1) at 90 min, respectively. Lung slices incubated with L- or D-CIPE had increased L- or D-CySH concentrations up to a max of 13.7 and 11.1 nmol mg(-1) and tracheal sections up to a max of 5.56 and 11.09 nmol mg(-1). In the lung slice medium, L- and D-CIPE levels had decreased by 75.2% and 74.0% at 90 min, respectively, and from the tracheal section medium, L- and D-CIPE concentrations had decreased by 66.7% and 32.7%, respectively. Preincubation of lung slices and tracheal sections with the carboxylesterase inhibitor, bis (p-nitrophenyl) phosphate (BNPP), almost completely prevented the disappearance of L- and D-CIPE extracellularly and greatly reduced the appearance of cellular L- and D-CySH. GSH, GSH isopropyl diester and gamma-glu-cys isopropyl diester elevated and prolonged GSH concentrations in rat lung slices, but GSH isopropyl monoester and gamma-glu-cys isopropyl monoester did not increase GSH levels. The uptake of L-CySH, but not D-CySH, is temperature sensitive in rat lung slices and tracheal sections and carboxylesterases appear to have a major influence on the uptake and metabolism of L- and D-CIPE by rat lung slices and tracheal sections.


Subject(s)
Cysteine/analogs & derivatives , Glutathione/analogs & derivatives , Lung/drug effects , Sulfhydryl Compounds/metabolism , Animals , Anions , Cysteine/metabolism , Cysteine/pharmacology , Esters , Female , Glutathione/metabolism , Glutathione/pharmacology , In Vitro Techniques , Lung/metabolism , Rats , Rats, Wistar , Trachea/drug effects , Trachea/metabolism
10.
Eur J Anaesthesiol ; 14(4): 421-7, 1997 Jul.
Article in English | MEDLINE | ID: mdl-9253571

ABSTRACT

The effect of a single pre-operative oral dose of controlled release diclofenac sodium on post-operative pain after minor gynaecological surgery was investigated. Fifty-two women took part in a double-blind controlled study. Pain was assessed by visual analogue scale (VAS), a four-point verbal rating score, and the requirement for post-operative analgesia. Those patients who received diclofenac had significantly less post-operative pain than the placebo group up to 2 h after surgery.


Subject(s)
Analgesics, Non-Narcotic/therapeutic use , Diclofenac/therapeutic use , Genital Diseases, Female/surgery , Pain, Postoperative/prevention & control , Premedication , Analgesics, Non-Narcotic/administration & dosage , Anesthesia , Delayed-Action Preparations , Diclofenac/administration & dosage , Double-Blind Method , Female , Humans , Male , Pain Measurement
11.
J Cell Sci ; 110 ( Pt 14): 1665-72, 1997 Jul.
Article in English | MEDLINE | ID: mdl-9247200

ABSTRACT

We show in the present study that homologs of hsp90 and hsp70 are induced by heat shocks in Tetrahymena and appear to form a high molecular mass complex (approximately 700 kDa) with tubulin. Three members of the hsp70 family (hsp72, 73, and 78) and one member of the hsp90 family (hsp82) have been identified by immunological or by a combination of immunological and sequencing methods. The known components of the 700 kDa complex and the conditions under which it can be recovered suggest that it may be an induced protective assemblage rather than a normal processing intermediate. Immunoblotting and immunofluorescence studies suggest further that large amounts of hsp73 and lesser amounts of hsp82 are associated with mature microtubules in both cilia and the cortex in this cell type. Some site-specific localizations of the identified heat shock proteins were also noted in non-microtubular components of the cell cortex.


Subject(s)
Cilia/chemistry , HSP70 Heat-Shock Proteins/analysis , HSP90 Heat-Shock Proteins/analysis , Tetrahymena/chemistry , Tubulin/analysis , Animals , Antibody Specificity , Autoradiography , HSP70 Heat-Shock Proteins/immunology , HSP90 Heat-Shock Proteins/immunology , Hot Temperature , Microscopy, Fluorescence , Tetrahymena/ultrastructure , Tubulin/immunology
12.
J Eukaryot Microbiol ; 42(4): 422-7, 1995.
Article in English | MEDLINE | ID: mdl-7620468

ABSTRACT

Twelve monoclonal antibodies were raised that are specific for the membrane skeleton of Tetrahymena. Five were directed against T. pyriformis and seven were directed against T. thermophila. Some cross-reactivity between species was found. Each monoclonal antibody recognized one of the three major components of epiplasm, i.e. the bands A, B, and C identified in electrophoretic separations of epiplasmic proteins. It was found, using these antibodies, that the epiplasmic proteins A, B and C have overlapping but independent distributions within the cell.


Subject(s)
Membrane Proteins/analysis , Protozoan Proteins/analysis , Tetrahymena pyriformis/cytology , Tetrahymena thermophila/cytology , Animals , Antibodies, Monoclonal , Antibody Specificity , Cell Membrane/ultrastructure , Immunohistochemistry , Mice/immunology , Microscopy, Immunoelectron , Tetrahymena pyriformis/ultrastructure , Tetrahymena thermophila/ultrastructure
13.
Dev Biol ; 169(2): 644-61, 1995 Jun.
Article in English | MEDLINE | ID: mdl-7781905

ABSTRACT

Much of the cell surface on the ciliate Tetrahymena thermophila is covered by a polarized lattice of cytoskeletal structures that are associated with basal bodies of the ciliary rows. Unique structural landmarks, including an oral apparatus and contractile vacuole pores, develop before cell division in localized domains located, respectively, posterior and anterior to the transverse fission zone. All of these structures can be visualized by specific monoclonal antibodies. A single-locus recessive mutation, disorganized-A (disA), primarily affects the striated rootlets of the ciliary-row basal bodies and brings about a severe disorganization in the positioning and orientation of these basal bodies and associated cytoskeletal elements. Nonetheless, the new oral apparatus, contractile vacuole pores, and other unique structures appeared at or near their normal sites along the anteroposterior axis of disA cells, indicating that the positioning of these localized structures is not dependent on the integrity of the ciliary rows. Abnormalities were present in the details of construction of some of the localized structures and in aspects of cell shape that may be influenced by these details. In the main, however, analysis of disA mutant cells indicates that intracellular domains near the cell poles develop independently of the vectorial polarity of the ciliary rows.


Subject(s)
Cell Polarity/genetics , Cytoskeleton/ultrastructure , Tetrahymena thermophila/genetics , Alleles , Animals , Cell Division/genetics , Cilia/ultrastructure , Genes, Protozoan , Genes, Recessive , Microscopy, Electron , Microtubules/ultrastructure , Mutation , Tetrahymena thermophila/cytology
15.
J Eukaryot Microbiol ; 41(5): 483-95, 1994.
Article in English | MEDLINE | ID: mdl-7804251

ABSTRACT

Certain monoclonal antibodies interact with proteins of Tetrahymena thermophila found in the conjugation junction as well as around the gametic nuclei (pronuclei) of conjugating cells; they also react with the oral primordium and fission zone of vegetative cells and with the cytoproct and contractile vacuole pores of all cells. One of these (FXIX-3A7) was investigated in detail. Immunogold labelling suggests that the material labelled by the 3A7 monoclonal antibody, which we call "fenestrin," is located beneath the epiplasm (membrane skeleton). Immunoblots reveal that the major and perhaps sole antigen is a 64 kDa polypeptide, found in two isoelectric variants. Developmental studies implicate fenestrin in two processes involved in conjugation. The first is "tip transformation." During preliminary starvation ("initiation"), labelling of fenestrin first appeared as a spot at the anterior end of starved mature cells, then after mixing of different mating types ("costimulation") it extended posteriorly along the anterior suture. After pairing, this region spread to form a widened plate. The second process is pronuclear transfer. Fenestrations representing channels between the conjugating cells began to appear 0.5 to 1 h after the conjugants united, and eventually merged to form a small number of temporary large holes during exchange of the transfer pronuclei. A fenestrin envelope also enclosed both the transfer and resident pronuclei; a strand of fenestrin connected the two. Shortly after pronuclear transfer, both transfer and resident pronuclei were released from fenestrin caps and fused to produce a zygotic nucleus (synkaryon) not associated with fenestrin Fenestrin thus appears to be intimately involved in the process of pronuclear exchange.


Subject(s)
Protozoan Proteins/metabolism , Tetrahymena thermophila/genetics , Tetrahymena thermophila/metabolism , Animals , Antibodies, Monoclonal , Cell Nucleus/metabolism , Conjugation, Genetic , Immunohistochemistry , Protozoan Proteins/immunology
17.
J Protozool ; 39(4): 508-10, 1992.
Article in English | MEDLINE | ID: mdl-1403985

ABSTRACT

The four immobilization antigens controlled by the SerH locus in Tetrahymena thermophila have been isolated and partially characterized (Doerder, F.P. & Berkowitz, M.S. 1986. Purification and partial characterization of the H immobilization antigens of Tetrahymena thermophila. J. Protozool., 33:204-208). We show here, using immunoprecipitation and electrophoresis after labeling with 35S-methionine, 14C-mannose, 14C-glucosamine, and N-Acetyl-D-[l-3H]glucosamine, that these proteins are glycosylated. We suggest the immobilization antigens in Tetrahymena may be anchored to the surface membrane by phosphatidylinositol glycans.


Subject(s)
Antigens, Protozoan/chemistry , Antigens, Surface/chemistry , Glycoproteins/chemistry , Protozoan Proteins , Tetrahymena thermophila/chemistry , Animals , Autoradiography , Electrophoresis, Polyacrylamide Gel
18.
J Struct Biol ; 108(3): 187-94, 1992.
Article in English | MEDLINE | ID: mdl-1476826

ABSTRACT

There is a complex system of 2- to 5-nm filaments in the oral apparatus of Tetrahymena. Four major subunit proteins, called tetrins, have been isolated from the filaments. These proteins, showing apparent molecular weights in polyacrylamide gels of 79-89 kDa, will assemble in vitro into 2- to 5-nm filaments. Tetrin filaments in vivo show different packing arrangements in different regions of the oral apparatus. We sought to determine the distributions of tetrin polypeptides within the complex oral structure by obtaining monoclonal antibodies specific for individual tetrins, then mapping their distributions within the oral apparatus using standard fluorescence microscopy, confocal laser scanning fluorescence microscopy, and electron microscopy. The results indicate that the four tetrin polypeptides are colocalized everywhere within the oral apparatus of Tetrahymena. Tetrin-binding proteins or specific nucleating structures may need to be invoked to explain the complex organization of the tetrin network. The 16 monoclonal antibodies obtained were also used to search for evidence of immunological relationships between tetrin and cytoskeletal proteins in multicellular organisms. None was found.


Subject(s)
Microtubule-Associated Proteins/metabolism , Tetrahymena/metabolism , Animals , Antibodies, Monoclonal , Fluorescent Antibody Technique , Microscopy, Immunoelectron , Microtubule-Associated Proteins/chemistry , Microtubule-Associated Proteins/immunology , Molecular Weight , Protein Conformation , Tetrahymena/ultrastructure
19.
J Protozool ; 39(1): 54-8, 1992.
Article in English | MEDLINE | ID: mdl-1560420

ABSTRACT

Immunoblotting tests involving cytoskeletal protein arrays and fluorescence microscopical examinations of whole cells using monoclonal antibody 424A8 gave substantially different results in three evolutionary subgroups within the genus Tetrahymena. These responses are described and some implications of the evolutionary divergence indicated in this ciliated protozoan are discussed.


Subject(s)
Biological Evolution , Polymorphism, Genetic , Protozoan Proteins/genetics , Tetrahymena/genetics , Animals , Antibodies, Monoclonal , Electrophoresis, Polyacrylamide Gel , Immunoblotting , Microscopy, Fluorescence
20.
Exp Cell Res ; 197(2): 137-9, 1991 Dec.
Article in English | MEDLINE | ID: mdl-1835696

ABSTRACT

Biochemical evidence is presented for the presence of cyclin in Tetrahymena. Zeuthen previously postulated the existence of a heat-labile "division protein" to explain heat-shock-induced division synchrony in Tetrahymena [(1964) Synchrony in Cell Division and Growth (Zeuthen, E., Ed.), pp. 99-158, Interscience, New York]. We show that cyclin is heat-labile in Tetrahymena and suggest that cyclin may be Zeuthen's division protein. Cyclin and cell cycle control is of interest in Tetrahymena because the division mechanism drives macronuclear amitosis, closed and acentric micronuclear mitosis, and cortical differentiation in this cell type.


Subject(s)
Cyclins/physiology , Tetrahymena pyriformis/growth & development , Animals , Autoradiography , Cell Cycle , Cell Division , Kinetics , Methionine/metabolism , Protein Biosynthesis , Proteins/isolation & purification , Sulfur Radioisotopes , Tetrahymena pyriformis/cytology
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