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PubMed1986

Decreased autolysis of dead cells in adriamycin-resistant lines of the sarcoma 180 of mouse.

Adriamycin-resistant cell lines of the sarcoma 180 of mouse reveal, besides the known resistance mechanism, a decrease in cellular autolysis compared with the original line. This decrease has been demonstrated by comparative analysis of cell-free supernatants isolated from 7-day-old sensitive and resistant ascites tumors in mice. In order to demonstrate these changes we isolated and quantified the DNA, detecting higher amounts within the supernatants of resistant lines. Furthermore, unspecific DNA-cleaving activity within raw homogenates of the cells is substantially lower in the resistant lines. Residual parts of chromatin may trap the drug and in this way lower its effective concentration. However, the results may also reflect changes in enzymatic complement playing a hitherto unknown role within living cells.

Animals↗
PubMed1980

Scanning electron microscopy of the human cochlea--postmortem autolysis artefacts.

Changes in the ultrastructure of the cochlea due to postmortem autolysis make the assessment of the normal or damaged anatomy difficult. Three methods of preserving the human cochlea were compared on the basis of the state of preservation of the sensory cell hairs of the organ of Corti as seen in the scanning electron microscope. Perfusion of the perilymphatic space with a glutaraldehyde-formaldehyde fixative within 40 min of death gave preservation as good as that seen in animal studies. Injecting formalin into the middle ear within 40 min of death allowed artefacts to develop when compared with the control ear which had been perfused with fixative. Refrigeration and early removal of the temporal bone gave poor preservation of surface structures.

Autolysis↗
PubMed1986

Autolysis of the granular layer of the cerebellar cortex in brain death.

In a study of duration of brain death, granular layer autolysis (GLA) of the cerebellar cortex was analyzed in 45 patients who died of acute cerebrovascular diseases (CVDs). Twelve patients who died of causes other than intracranial disease served as controls. Tonsillar herniation occurred in all who died of acute CVDs. More advanced GLA was seen in the central folia adjacent to the central white medullary body of the cerebellum as compared with the peripheral folia. Widespread GLA involving the most of the peripheral folia was found solely in patients in whom brain death had been present over 18 h. Of the 12 control patients, 4 showed GLA only in the central folia. Although GLA of the central folia might develop during immersion fixation of the brain, the alteration of the peripheral folia is assumed to develop in the period of brain death. Widespread GLA extending to the peripheral folia could be a pathological finding characteristic of brain death, where intracranial blood flow could be absent or significantly reduced. Brain death for little less than 1 day would be necessary for GLA to develop.

Adult↗
PubMedDate not supplied

Comparative biochemistry and fine structure of atrial and ventricular myocardium during autolysis in vitro.

In a previous study we found that the development of fine structural alteration in atrial myocardium made ischaemic in vivo was slower than has been observed for ventricular myocardium. To explore possible reasons for this, parallel samples of atrial (A) and ventricular (V) myocardium undergoing autolysis (ischaemic necrosis) in vitro at 37 degrees C were studied for up to 2 hours. At 15-minute intervals tissue was snap-frozen for measurement of pH, lactate, and adenine metabolites by HPLC. In half the experiments comparable specimens were taken for electron microscopic examination as well. Fine structural alteration developed less uniformly and more slowly in A than in V. The most striking metabolic differences between A and V were: A had a consistently higher tissue pH and lower lactate level The sum of the adenine + hypoxanthine metabolites was essentially constant but significantly different for each (A = 5.04 +/- 0.12 (s.e.m.), V = 7.71 +/- 0.15 (s.e.m.) mumol/g wet tissue weight) Initial ATP levels were lower (40% less) in A The maximum accumulation of AMP was higher in A, despite its smaller pool of adenine metabolites Both adenosine and inosine showed slower rates of change in A. These results suggest that during early, severe ischaemic injury A and V show differing activities of 5'-nucleotidase.

Adenosine Diphosphate↗
PubMed1981

Studies on the pathogenesis of ischemic cell injury. VI. Mitochondrial flocculent densities in autolysis.

Flocculent densities in the matrix of mitochondria have become quite important in cell pathology since, when prominent, they indicate irreversible cell injury. The morphology and chemical nature of these flocculent densities have been studied in Kidney after various periods of autolysis in vitro in whole tissue samples and in isolated mitochondria. After 30 to 60 min of ischemia, flocculent densities were seen only occasionally and they were most prominent in samples subjected to mechanical damage during isolation. However, in 2- and 4-h samples numerous densities were seen. The size of the densities increased with time, being about 1,400 A in diameter at 4 h. Densities were also seen in mitochondria isolated in medium containing EDTA. They were seen only in the mitochondrial matrix, and could occasionally be found in condensed mitochondria. Small densities were generally round but larger one varied in shape and often appeared as aggregates of smaller densities. Digestion of the densities from water-soluble glycol methacrylate embedded samples was successful with pronase, but neither acid nor lipid solvents were effective. calcium or inorganic phosphate content of isolated mitochondria did not show an increase parallel to the occurrence of flocculent densities. The results suggest that the densities consist predominantly of protein and are probably formed through denaturation of proteins of the mitochondrial matrix and/or the inner membrane.

Animals↗
PubMed1981

Effects of postmortem autolysis on the lipids of rat spinal cord.

The lipid composition of rat spinal cord undergoing postmortem autolysis for 3 min and for 4 h at 38 degrees C was investigated as a model for lipid changes in total spinal cord ischemia. The only change in cords incubated for 3 min was an 11.7% decrease in cholesterol/g fresh weight. The cords incubated for 4 h showed a similar 11.6% decrease in cholesterol/g fresh weight as well as a 5.6% increase in water content and a 22% decrease in phosphatidyl serine. Changes of marginal statistical significance included a 15% increase in lipid phosphorus/g dry wt. and a 15% decrease in G4 (GM1)1 in the 4 h incubated cords. Therefore, autolytic processes are of little consequence in total spinal cord ischemia and attention should now be focused on exogenous pathogenetic factors to explain such ischemic changes in spinal cord. We also report discovery of an alkali-labile ganglioside, G1a in rat spinal cord.

Animals↗
PubMed1990

Autolysis of isolated adipocytes by endogenously produced fatty acids.

Isolated rat adipocytes, in which lipolysis was maximally stimulated by isoproterenol, continued to produce fatty acids in excess of the high-affinity binding capacity of the fatty acid acceptor bovine serum albumin in the incubation medium. At an average of 17 mol fatty acids/mol serum albumin, there was a burst of lactate dehydrogenase activity recovered in the incubation medium, indicating cell lysis. It is concluded that endogenously produced fatty acids will cause autolysis of adipocytes in vitro. Actively lipolysing adipocytes were more fragile than resting cells, since increasing amounts of lactate dehydrogenase activity was recovered in the medium during active lipolysis.

Adipose Tissue↗
PubMed1991

Differential antigen preservation during tissue autolysis.

Immediate fixation or snap freezing of tissue is ordinarily done to maximize antigen preservation for immunocytochemistry; however, delay in tissue allocation or spontaneous lymph node infarction can render tissue suboptimal for immunostaining. To test the effects of tissue autolysis/necrosis on the preservation of various lymphoid, epithelial, and mesenchymal markers, two lymph nodes (one with reactive lymphoid hyperplasia and one with metastatic ductal breast carcinoma) were evaluated for immunocytochemically demonstrated antigen preservation at 0-, 4-, 8-, 12-, 24-, 48-, and 72-hour intervals of autolysis at 37 degrees C. All specimens were stained by frozen section and formalin-fixed paraffin section immunocytochemical reactions with antibodies against CLA (CD45), UCHL-1 (CD45RO), L-26, kappa, lambda, anti-epithelial keratins (AE-1 and AE-3), epithelial membrane antigen, and vimentin. Frozen sections were additionally stained for Leu-1 (CD5), Leu-2a (CD8), Leu-3a+b (CD4), Leu-4 (CD3), and Leu-14 (CD22). The most resilient lymphoid antigen preservation was observed with CLA and UCHL-1, both exhibiting immunoreactivity at 72 hours in both frozen and fixed preparations. L-26 showed similar reactivity in frozen sections, but detectable antigen was observed only up to 24 hours in formalin-fixed tissue. Leu-2a proved to be the most labile antigen, persisting for only 12 hours in frozen sections. The epithelial markers epithelial membrane antigen and AE-1 exhibited excellent antigenic preservation in both frozen and fixed preparations; AE-3 persisted well in frozen section but was not demonstrated in fixed tissue. Vimentin immunoreactivity was vastly superior in frozen, as compared with fixed, tissue sections. Most antigens showed remarkable preservation despite morphologic degradation; however, differential antigenic resilience was demonstrated. Knowledge of this variation in antigen decay is critical for evaluation of immunoperoxidase phenotypic studies of autolyzed or necrotic tissue.

Antigens↗
PubMed1979

Alanine aminopeptidase activity and autolysis in the tails of Rana catesbeiana larvae during metamorphosis.

1. Alanine aminopeptidase activity and autolysis increase concomitantly in tail tissue of Rana catesbeiana tadpoles during metamorphosis. 2. significant increases first appear at Taylor and Kollros state XX and coincide with the beginning of tail regression as determined by the tail wt body wt ration. 3. The results suggest a role of alanine aminopeptidase in the mechanism of tail resorption.

Aminopeptidases↗
PubMed1992

Comparative studies on heat stability and autolysis of scallop (Patinopecten yessoensis) calpain II-like proteinase and rabbit calpain II.

1. The scallop calpain-like proteinase is about five times more labile than the rabbit calpain II upon heat treatment at 35 degrees C. 2. By autolysis of the scallop proteinase of two 100 kDa subunits, 90, 45 and 30 kDa fragments were formed. Thereby the activity decreased monophasically in the presence of millimolar order of Ca2+, but did not increase in the presence of micromolar order of Ca2+ unlike the rabbit calpain II.

Animals↗
PubMed1988

Intravascular "mulberry-like" bodies: morphological, immunohistochemical, and ultrastructural observations of an incidental finding caused by autolysis?

Intravascular "mulberry-like" bodies in a stillborn female infant with moderate maceration are reported. The histogenesis of these structures is discussed based on light-microscopic, immunohistochemical and ultrastructural findings. No demonstrable causal relation between the intravascular lesions and fetal death was found, the cause of death being attributed to intrauterine asphyxia. It is concluded, that intravascular "mulberry-bodies" most likely represent artifacts due to red blood cell autolysis.

Adult↗
PubMed1970

Autolysis of cell walls of Bacillus stearothermophilus B65 and the chemical structure of the peptidoglycan.

1. The cell walls of Bacillus stearothermophilus B65 contain glucosamine, muramic acid, alanine, alphain-diaminopimelic acid (Dap), glutamic acid, aspartic acid, glycine, and serine in the molecular proportions 0.60:0.64:2.30:0.85:1.00:0.11:0.13:0.31. 2. Both d- and l-alanine are present, but glutamic acid and diaminopimelic acid are present only as the d- and meso-isomers respectively. 3. The peptide fragments Ala-Dap, Dap-Ala, and Dap-Ala-Dap have been isolated from a partial acid hydrolysate of the cell walls. 4. The major products of autolysis of the cell wall were d-alanine, a peptide mixture, peptidoglycan material and a peptidoglycan-teichoic acid complex. 5. Separation of the peptide mixture into ten major peptides was achieved by DEAE-Sephadex and paper chromatography, and paper electrophoresis. 6. The structures of these peptides have been determined and they fall into four groups, the individual members of each group differing only in number or position of carboxamide substituents. 7. The structures are I, a tripeptide l-Ala-d-Glu-meso-Dap; II, a pentapeptide made up by the tripeptide (I) linked through the in-amino group of its diaminopimelic acid residue to the carboxyterminal of the dipeptide meso-Dap-d-Ala; III, a heptapeptide made up by a similar linkage between the tripeptide (I) and the tetrapeptide l-Ala-d-Glu-meso-Dap-d-Ala; IV, a possible undecapeptide made up by a further tetrapeptide similarly linked to the heptapeptide (III) structure. 8. The structure of the peptidoglycan and the actions of the autolytic enzymes are discussed in terms of these peptide structures.

Amino Acids↗
PubMed1970

Analytical study of the degradation of nucleohistone during calf thymus chromatin autolysis.

The mechanism of nucleohistone degradation in calf thymus chromatin during autolysis of the latter involves a release of lysine-rich histone fractions, followed by degradation of the thus-exposed DNA portions; the latter portions are richest in adenine-thymine sequences. After this degradation process, residual nucleohistone fragments of low molecular weight (10(5)) remain. Their chemical composition is special, in that the DNA contains a larger proportion of guanine-cytosine sequences than does the initial DNA and it is combined with arginine-rich histones.

Adenine↗
PubMed1969

Promotion of the autolysis of alpha-chymotrypsin by Evans blue.

Evans blue has been demonstrated to promote the autolysis of alpha-chymotrypsin at low dye-to-protein ratios in alkaline solution. This effect has been attributed to the stabilization of less tightly folded conformers of the protein by the dye. The effect is specific. Of 20 other strongly acidic dyes tested, only trypan red showed activity comparable to that of Evans blue. A general discussion of the influence of ligand binding on the stability of proteins is presented.

Autolysis↗
PubMed1957

Staphylococcal virolysin, a phage-induced lysin; its differentiation from the autolysis of normal cells.

Virolysin is a lysin which appears in Staphylococcus aureus K(1) cells infected with phage P(14); together with phage, virolysin is released from phage-infected cells at the time of lysis. Autolysin is a lysin formed by uninfected cells of the K(1) strain; autolysin is released from uninfected cells by autolysis. They show the following similarities: Both agents act within the genus Micrococcus. They lyse cells only after the cell has been subjected to a damaging or "sensitizing" treatment, such as heat, bacteriophage, acetone, or ultraviolet irradiation. The course of lysis of heated cells by both lysins has been found to proceed in a similar manner. A constant percentage of cells is lysed, independent of the concentration of lysin; the residual cells remain resistant to either lysin. Lysis proceeds logarithmically with time, and the velocity constants K are proportional to the lysin concentration. K increases with increasing temperature. Both lysins are unaffected by antiserum to the phage. They are inhibited alike by a number of chemicals, including known enzyme inhibitors. Both agents are destroyed by proteolytic enzymes and are precipitated by 40 per cent saturation with (NH(4))(2)SO(4). Both lysins are very thermolabile. The two lysins differ with respect to their pH optimum, antigenic relationship and specificity for Micrococcus lysodeikticus. These results suggest that (1) both lysins have many properties associated with enzymes, (2) the lysis of heated cells, which they produce, has some of the characteristics of a chemical reaction, (3) the lysin from the phage-infected cell is clearly different from the lysin of the uninfected cell.

Autolysis↗
PubMed2004

Blocking of human immunodeficiency virus type-1 virion autolysis by autologous p2(gag) peptide.

Our previous study suggested that the p2(gag) peptide, AEAMSQVTNTATIM, inhibits human immunodeficiency virus type 1 (HIV-1) protease (PR) activity in vitro. In this study, Ala substitutions (Met4Ala and Thr8Ala) and deletion of amino acid Asn9 within the nona p2(gag) peptide (AEAMSQVTN) were found to decrease the inhibitory effect on HIV-1 PR activity. Furthermore, treatment of PMA-activated latently infected T lymphocytes, ACH-2 cells, with the p2(gag) peptide (100 and 250 micro M) resulted in a decrease in the amount of p24(gag )in the resultant viral lysates derived from the cell-free supernatant. In addition, the HIV-1-Tat-p2(gag) fusion peptide was synthesized to effectively deliver the p2(gag) peptide into the cells. The fusion peptide was incorporated into chronically infected T lymphocytes, CEM/LAV-1 cells, as detected on indirect immunofluorescence analysis using anti-p2(gag) peptide monoclonal antibodies, which recognize the nona peptide (AEAMSQVTN) derived from the N-terminus of the p2(gag) peptide, and cleaved by HIV-1 PR in vitro. Treatment of CEM/LAV-1 cells with the fusion peptide also resulted in a decrease in the amount of p24(gag )in the resultant viral lysate derived from the cell-free supernatant. Taken together, these data suggest that the p2(gag) peptide consequently blocks the autolysis of HIV-1 virions for the conservation of viral species.

Amino Acid Sequence↗
PubMed1990

Isolation and characterization of autolysis-defective mutants of Escherichia coli that are resistant to the lytic activity of seminalplasmin.

Two temperature-sensitive autolysis-defective mutants of Escherichia coli were isolated and shown to be resistant to lysis induced by seminalplasmin, an antimicrobial protein from bovine seminal plasma, as well as to lysis induced by ampicillin, D-cycloserine and nocardicin, at 37 or 42 degrees C but not at 30 degrees C. The mutants were, however, sensitive to inhibition of RNA synthesis by seminalplasmin even at the nonpermissive temperature. Temperature-resistant revertants of the mutants were sensitive to lysis induced by the various antibiotics at 37 or 42 degrees C. The mutations in both strains were mapped at 58 min on the E. coli linkage map. The lysis resistance of the mutants was phenotypically suppressed by the addition of NaCl. Partial suppression of the lysis-resistant phenotype was also observed in a relA genetic background.

Ampicillin Resistance↗
PubMed1994

The gene of the N-acetylglucosaminidase, a Bacillus subtilis 168 cell wall hydrolase not involved in vegetative cell autolysis.

lytD, the structural gene of the Bacillus subtilis 168 N-acetylglucosaminidase was localized at 310 degrees, next to the tagABC operon. Sequence analysis revealed a monocistronic operon encoding a 95.6 kDa protein endowed with an export signal, the cleavage of which yields the monomer polypeptide (92.8 kDa) of the dimeric active form of the enzyme. Transcription is initiated at a sigma-D (sigma D)-dependent promoter and ends at a terminator common to lytD and the divergently transcribed tagABC operon. In addition, we report the sequence of the adjacent upstream ORF, transcribed in the same direction as lytD, which shows significant homology to phosphomannose isomerase-encoding genes. Cell separation, motility, autolysis, cell wall turnover and growth were not affected in strains devoid of the N-acetylglucosaminidase. A mutant deficient in the two most abundant autolysins, i.e. the LytC amidase and the glucosaminidase, exhibited the phenotype of the amidase-deficient strains, revealing their non-requirement for growth. This conclusion raises two fundamental questions: how does the cell undo the highly cross-linked peptidoglycan so as to be able to grow, and what is the role of the considerable amount of autolysin normally present? Possible answers to these questions are discussed.

Acetylglucosaminidase↗