[Lipoteichoic acid from Staphylococcus aureus: regulation of autolysis and killing of penicillin. I. Role of lipoteichoic acid as a regulator of autolysis].
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Autolysis↗
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[Autolysis in fungi. I. Autolysis of Coprinus and in fungal cultures].
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Agaricales↗
Influence of autolysis on rat gastric endocrine cells. Histochemical and electron microscopical study.
In the present study histochemical parameters of the rat gastric endocrine cells were followed up in the course of 24-h autolysis, and their ultrastructure was studied during autolysis lasting for 60 min. The autolysis occurred at 37 degrees C. In the light microscope, with the histochemical methods applied, only EC, ECL and G cells could be identified during the one-hour autolysis. With the autolysis proceeding for 6 and 12 h, only argyrophil method according to Grimelius (1968) enabled visualization of gastric argyrophilic cells. After 24 h of autolysis, none of the methods applied (not even the Grimelius method) proved to be adequate for successful demonstration of the gastric endocrine cells. In the course of 60-min autolysis, electron microscopic examination provided identification of the EC, ECL, AL, D1, and G cells with the characteristical ultrastructural appearance of granules. The granules of the endocrine cells (G cells included) were found to be considerably resistant to autolysis. The effect of 60-min autolysis did not induce granule "emiocytosis" or dissolution of granule content. Autolysis exceeding five minutes resulted in damage of the mitochondria of different degrees and in dilatation of the profiles of endoplasmic reticulum (particularly in G and AL cells). The results obtained in the present study demonstrate the feasibility of in vitro experimental stimulation since the endocrine granules have proved to be resistant to the effects of simultaneously developing autolysis.
Animals↗
Electron microscopical and enzyme histochemical changes in the rat myocardium during prolonged autolysis.
The effect on rat myocardium of autolysis at 19 degrees C, for up to 20 days, was studied by electron microscopy and enzyme histochemistry. The enzymes studied included monoamine oxidase (MAO), sytochrome oxidase (CytO), non-specific esterase ((Ns.E.), phosphorylase (P-ase), succinate dehydrogenase (SDH) and various NAD- and NADP-linked dehydrogenases. The myocardium lost its histochemical P-ase activity within a few hours of autolysis, whereas the activity of all other enzymes remained quite normal for at least about 4 days, except that of MAO and SDH, which were normal for about 8 and 12 days, respectively. The myocardial cells lost activity of various enzymes in a patchy manner during prolonged autolysis and practically all histochemical enzyme activity disappeared within 20 days. The early period of autolysis was accompanied by rapid ultrastructural changes of myocardial cells. During prolonged autolysis the gross architecture of the myocardium was lost gradually by the 12th to 20th days. Mitochondria were the organelles most resistant to the effects of autolysis, and numerous mitochondria with morphologically solid inner and outer membranes were seen among the totally disintegrated myocardium 20 days after death. The loss of P-ase activity coincided with the loss of glycogen. The loss of MAO, SDH and CytO activities was not closely related to the morphological preservation of mitochondria, but, in accordance with other enzymes, was more closely related to the disintegration of the over-all myocardial structure. The present results showed that the architecture of the myocardium, and especially that of the mitochondria, was surprisingly resistant to the effects of autolysis at room temperature. Also several enzymes of the myocardium other than those examined so far maintained quite stable histochemically demonstrable activity during prolonged autolysis. These observations give support to the possibility of making the diagnosis of myocardial infarction at postmortem more accurate than with the present morphological and histochemical routine methods.
Alcohol Oxidoreductases↗
Autolysis in strains of viridans streptococci.
Seven strains of viridans streptococci of the species Streptococcus sanguis, S. mutans and S. mitis were investigated for autolysis. The effect of pH, salt concentration and temperature on the autolytic process was studied in Na2HPO4/NaH2PO4 buffer. Whole cells and walls of all strains autolysed most rapidly at pH values above 7. Autolysis of whole cells of S. sanguis and one strain of S. mitis (ATCC15909) was maximal in 0-05 TO 0-2 M buffer, while the two S. mutans strains and S. mitis ATCC15912 showed maximal autolysis in 0-5 and 1-0 M buffers. Cultures harvested in the stationary phase of growth possessed only slightly decreased autolytic activity compared with those from the exponential phase. Whole cells autolysed more rapidly at 37 degrees C Than at 45 degrees C and 10 degrees C. Autolysis of isolated walls of three strains of S. mitis (ATCC903, ATCC15909 and ATCC15912) was maximal at pH 7-0 AND 7-5 and in 1-0 M buffers. Streptococcus mitis ATCC15909 also showed maximal lysis in 0-01 M and 0-5 M buffers. An endopeptidase action of the autolytic system of S. mitis ATCC15912 was indicated by the progressive release of soluble amino groups during autolysis of the walls. No release of reducing groups was observed. Several free amino acids were released during autolysis of these walls, alanine, lysine and glutamic acid being in greatest quanitity.
Amino Acids↗
Autolysis of Neisseria gonorrhoeae.
Physiological conditions that would provide maximal rates of autolysis of Neisseria gonorrhoeae were examined. Autolysis was found to occur over a broad pH range with the optimum at pH 9.0 IN 0.05 M tris(hydroxymethyl)amino-methane-maleate buffer. The temperature optimum was found to be 40 C. Potassium ions greatly stimulated autolysis at a concentration of 0.01 M. Exposure of growing N. gonorrhoeae cells to penicillin, vancomycin, or D-cycloserine influenced the susceptibility to the autolysis, whereas chloramphenicol afforded some protection against autolysis. The primary structure of the peptidoglycan is composed of muramic acid/glutamic acid/alanine/diaminopimelic acid/glucosamine in approximate molar ratios of 1:1:2:1:1, respectively. Exogenous radioactive diaminopimelic acid, D-glucosamine, and D-alanine were incorporated into peptidoglycan. During autolysis these radioactive fragments were released from cells.
Alanine↗
Investigation of the short-time autolysis of rat hearts by means of SDS. Polyacrylamide gel electrophoresis and electron microscopy.
The short-time autolysis of hearts was regarded as a model of ischaemic heart failure. Therefore, isolated rat hearts were subjected to 30--120 min autolysis in a Locke solution at 37 degrees C. Electron microscopic examinations and myofibrillar preparations were made from the autolysed heart ventricles. The myofibrillar proteins were resolved by SDS-polyacrylamide gel electrophoresis. After 30 min autolysis the amount of a protein of 192,000 daltons greatly increased. At the same time on the electron micrographs the focal destruction of filament destruction on the A filament area and the mitochondrial structure altered too. After 60 min autolysis another protein of 36,400 daltons appeared. On the electron micrographs the focal desintegration of Z membranes and the focal destruction of I filaments can be observed. After 120 min autolysis further proteolytic products could not be detected by gel electrophoresis but on the electron micrographs the destruction of Z membranes and I filaments became more pronounced.
Animals↗
Cell envelope of Neisseria gonorrhoeae: relationship between autolysis in buffer and the hydrolysis of peptidoglycan.
Neisseria gonorrhoeae readily underwent autolysis when suspended in N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid (HEPES) buffer at alkaline pH values. Autolysis was inhibited by the addition of Mg2+ or other divalent cations. Autolysis was also suppressed at acid pH (pH 6.0). Suspension of cells in buffer was accompanied by the hydrolysis of peptidoglycan. The rate of peptidoglycan hydrolysis in HEPES buffer was maximal at pH 8.5 and was similar in the presence or absence of Mg2+. Therefore, divalent cation stabilization against autolysis is not mediated by inhibition of peptidoglycan hydrolysis. Peptidoglycan hydrolysis occurred in HEPES buffer (pH 6.0), but at a rate that was 50% of the maximum. Incubation of cells with chloramphenicol or rifampin before suspension in HEPES buffer (pH 8.5) partially prevented autolysis; under these conditions, peptidoglycan hydrolysis still occurred, but at a reduced rate. Old and new peptidoglycans were hydrolyzed at similar rates. Peptidoglycan hydrolysis results in solubilization of both the peptide and glycan moieties.
Buffers↗
Ultrastructural nuclear changes of extranucleolar ribonucleoprotein structures during autolysis of normal liver cells.
The ultrastructural changes of extranucleolar nuclear ribonucleoprotein structures during autolysis of normal liver cells were studied by means of usual and cytochemical procedures. The results revealed that the earliest changes were characterized by the fragmentation of the perichromatin fibrils and disappearance of the perichromatin granules. This was followed by the formation of numerous dense granules among the altered perichromatin fibrils and by the disappearance of dense fibrillar structures from the remaining interchromatin areas. In the later stages of autolysis the altered perichromatin fibrils loosed their density and the dense granules located among them disappeared. In addition, fine filamentous and cross-striated bodies appeared in the nucleoplasm as well as in the cytoplasm of some hepatocytes. The results obtained by the EDTA treatment and digestion of the sections with Pronase and RNA-ase indicated that the altered perichromatin fibrils contained ribonucleoprotein which together with that of the perichromatin granules represent nuclear components most sensitive to the autolysis. The chemical nature of the dense granules located among the altered perichromatin fibrils was different from that of the latter as well as from that of the nuclear microspherules [6]. The dense fine filamentous and cross-striated nucleoplasmic and cytoplasmic bodies are considered to represent a nonspecific structural phenomenon accompanying regressive cellular alterations since these bodies were present only in the later stages of autolysis.
Animals↗
Autolysis of methicillin-resistant and -susceptible Staphylococcus aureus.
The autolytic activities, including unstimulated, Triton X-100-stimulated, and daptomycin-induced, of various sets of methicillin-resistant and related methicillin-susceptible strains were compared. Faster rates of autolysis were noted in two heterogeneous methicillin-resistant transductants than in their methicillin-susceptible parental recipients, in a heterogeneous resistant strain than in a susceptible derivative created by chemical mutagenesis, and in a homogeneous resistant strain than in a derivative that had decreased methicillin resistance and was created by transposon Tn551 mutagenesis. These results suggest that the presence of the methicillin resistance region, mec, either directly or indirectly through an interaction with other host genes, confers a faster rate of autolysis on strains. Various auxilliary genes are known to affect methicillin resistance expression, and one of these genes, femA, was necessary for the expression of this faster rate of autolysis. These differences in autolytic activities were not observed in isolated crude cell walls retaining autolytic activities, suggesting different modes of regulation of autolysins in intact cells and isolated walls. In contrast, one homogeneous, highly resistant strain, DU4916, had a lower autolytic activity than did derived heterogeneous resistant and susceptible strains created by chemical mutagenesis and a strain that had decreased resistance and was created by transposon mutagenesis. Our observations suggest that methicillin resistance expression is associated with an enhanced rate of autolysis, in heterogeneous resistant strains at least.
Autolysis↗
Role of teichuronic acid in Bacillus licheniformis: defective autolysis due to deficiency of teichuronic acid in a novobiocin-resistant mutant.
nov-12, a novobiocin-resistant mutant of Bacillus licheniformis ATCC 9945, grows as long chains of cells, a characteristic of autolytic-deficient (Lyt-) mutants. Isolated walls from nov-12 autolyzed at a rate equal to 5% of that displayed by wild-type walls, thus confirming the Lyt- phenotype. Protein-free nov-12 walls displayed marked resistance to, and also failure to bind, added autolysin solubilized from wild-type walls. Comparison of isolated cell walls revealed a deficiency in teichuronic acid in the mutant. Lesser differences were observed in walls of this strain, including a reduction in galactose, an increase in the proportion of peptidoglycan, and small quantitative differences in peptidoglycan composition though the proportions of protein and teichoic acid were similar in walls of both strains. Autolytic sensitivity was studied in walls in which protein, teichoic acid, and teichuronic acid were removed successively by selective extraction procedures. Autolysis of wild-type walls was unaffected by removal or protein or teichoic acid, but teichuronic acid removal rendered wild-type walls as insensitive to autolysis as mutant walls had been throughout. Therefore, in this mutant, deficiency in teichuronic acid alone leads to the Lyt- phenotype and, hence, activity and binding of autolysin(s) are dependent upon teichuronic acid but not teichoic acid. Also, the potential rate of autolysis of cell walls in this organism was correlated with the proportion of teichuronic acid in the wall. The possible significance of these findings with respect to control of autolysis and cell separation is discussed.
Acetylgalactosamine↗
[Influence of autolysis on the quantitative cytoarchitecture of rat hepatocytes. (An ultrastructural morphometric study) (author's transl)].
INTRODUCTION: Autolysis is very often a reason for cell damage and is also super-imposed on many other cell damages. Already one hour of autolysis causes serious changes in cell metabolism, which can be demonstrated morphometrically. MATERIAL AND METHODS: Experiments were made with 10 male adult Wistar rats. 5 animals were for control purposes and 5 animals had to undergo a 1-hour's autolysis. The morphometric analysis of the liver parenchymal cells was based on the information of Weibel et al. (1968) with the help of a computer program. RESULTS AND DISCUSSION: The consequence of the drop in energy caused by autolysis is an enlargement of the liver cell which is possibly due to a breakdown of the energy-dependent ionic pumps. One of the earliest observable cell changes is a so-called "Kernwandhyperchromatosis" and chromatin condensation within the nuclei, whereby the Kernwandhyperchromatosis is seen to be a direct consequence of the increase in lactate and decrease of pH. ATP-sufficiency causes a disturbed function of mitochondrial membranes. The microchondria are swollen, the number of mitochondrial grana is clearly reduced. An enlargement of the mitochondrial outer membrane takes place by folding while the surface of mitochondrial cristae remains unchanged. As a consequence of the altered membrane activities also the peroxisomes swell at reduced numerial density. At unchanged total volume of RER the surface of the granulated membranes of the RER decrease by 50%. This decrease caused by ribosome detachment of the granulated membranes corresponds to the enlargement of the degranulated membrane parts of the nedoplasmic reticulum. The vesiculation is caused by an unspecific damage of cytoplasm. While the density of its volume and the membrane surface remain unaltered, the SER also shows a tendency to small vesiculation caused by an unspecific damage of cytoplasm. The increase in number and volume of the lysosomes and vacuoles of unknown origin speaks for a lysosomal activity. The cell compartment responsible for protein synthesis shows the most impressive morphometric and morphologic changes, which eventually can be explained by a decrease of protein synthesis which is needed to obtain enough energy for a well operating physiological equilibrium.
Animals↗
[Course and modification of Hypomyces ochraceus m 359 autolysis].
Growth and natural autolysis of the ascomycete Hypomyces ochraceus were investigated in shake cultures by measuring dry weight, pH value, and uptake of carbohydrate. The alkaline autolysis resulted in maximum loss of 53% of dry weight during an incubation period of 35 days. Early autolysis was induced by limitation of oxygen, increasing temperature, addition of peracetic acid, and sodiumacide. Autolysis is discussed to be derived from deficiency of energy.
Azides↗
Lytic enzymes in the autolysis of filamentous fungi.
The degrees of autolysis attained by five different genera of filamentous fungi during an incubation period of 60 days, under the same culture conditions were: 87.3% for Penicillium oxalicum; 65.9% for Neurospora crassa; 62.7% for Polystictus versicolor; 51.7% for Aspergillus niger and 23.5% for Nectria galligena. N. crassa, A. niger and P. versicolor reached the end of the autolysis during this incubation period (60 days), whereas P. oxalicum and N. galligena did not. The excretion of the lytic enzymes beta-N-acetylglucosaminidase, beta -1-3 glucanase, chitinase, invertase and acid phosphatase into the culture medium during growth and autolysis was investigated. The excretion of these enzymes was consistent with the degree of autolysis reached, the maximum excretion belonging to P. oxalicum and the minimum to N. galligena. The N. crassa invertase was excreted into the culture liquid at levels very much higher than the other enzymes studied, and at levels very much higher than the invertases excreted by the other fungi.
Acetylglucosaminidase↗
Developmentally induced autolysis during fruiting body formation by Myxococcus xanthus.
The developmental events during fruiting body construction by the myxobacterium M. xanthus is an orderly process characterized by several sequential stages: growth leads to aggregation leads to formation of raised, darkened mounds of cells leads to autolysis leads to myxospore induction. The temporal sequence of autolysis followed by myxospore induction is consistent with the interpretation that developmental autolysis provides essential requirements for the surviving cells to induce to myxospores. At intermediate developmental times on agar plates a fraction of the cell population is irreversibly committed to lyse; i.e., lysis continues in liquid growth medium or in magnesium-phosphate buffer. Lysis is cell concentration independent and is therefore likely to be by an autolytic mechanism. The lysis sequence can be preliminarily characterized as having an early stage during which deoxyribonucleic acid synthesis continues and a later irreversible stage during which deoxyribonucleic acid synthesis does not occur. Irreversible lysis in liquid growth medium or in magnesium-phosphate buffer is initiated on agar plates during nutrient deprivation and such lysis results in the induction of a fraction of the population to myxospores. This induction is dependent upon the concentration of lysis products, thus providing evidence that developmentally induced autolysis is required for myxospore induction.
Bacteriolysis↗
Nuclear size and cytochemical changes during autolysis in free gingival autograft epithelium.
Karyometric and cytophotometric measurements of DNA and RNA have been evaluated in gingival graft epithelium. The study was conducted during the first 20 hours from the time of grafting when the graft epithelium undergoes a process of autolysis. Both basal cell and prickle cell layers were used. The results showed an increase in optical density for Feulgen-DNA according to the time of grafting. At the same time pentose nucleic acid (RNA) and nuclear size showed decreasing values. It was concluded that pycnosis was the usual course of nuclear autolysis in graft epithelium. In addition gingival graft epithelium was found to be an useful model for the study of cell autolysis in vivo.
Animals↗
Influence of osmotic pressure on transformable and non transformable variants of Neisseria meningitidis. 2. Growth and induction of autolysis.
The Neisseria meningitidis Strain M1 could grow in media made hypertonic with 0.7 M sucrose, but the growth rate was much reduced. The reduction was more pronounced in the competent (cp+) variant than in the incompetent (cp-) one. After exposure to increased osmotic pressure, growth was resumed after a pronounced lag which was regularly longer in the cp- variant. Cellular lysis took place during the lag. The lag could be shortened by the addition of MgCl2. N. meningitidis cells lysed slowly when suspended in various isotonic solutes, but rapid lysis was activated in exponential phase cells by exposure to hypotonic as well as to hypertonic conditions. This activation was more pronounced in the cp- variant than in the cp+ variant. In stationary phase cells there was very little activation of autolysis. The rate of autolysis was inhibited by MgCl2 and CaCl2 in low concentration. Osmotic fragility developed during autolysis in the presence of high concentrations of acetate or sucrose but not in the presence of high concentrations of NaCl or phosphate. MgCl2 increased the osmotic stabilization caused by acetate or sucrose, whereas CaCl2 in low concentration abolished the stabilizing effect of these solutes.
Acetates↗
[Degradation of transfer RNA from skeletal muscles of rats during autolysis].
sRNA were extracted from postmitochondrial fraction of rat sceletal muscles by the phenol method. Their yield, physico-chemical properties and acceptor activity during postmortal destruction were studied. Within 2 days after the death yield of sRNA was decreased by 18-20% with maintenance of the physico-chemical properties studied. At the same time the acceptor activity (towards 4 amino acids) was distinctly decreased. For various amino acids correlation between a decrease in the acceptor activity and the time of autolysis was different. Three peaks of radioactivity were observed when 14C-phenyl-alanine-sRNA was fractionated on DEAE-Sephadex A-25; two of them were distinctly decreased after 24 hrs autolysis but the third one was maintained almost without alterations. The data obtained suggest that separate types of sRNA are degraded selectively at early steps of postmortal autolysis.
Amino Acyl-tRNA Synthetases↗