Chromosoma, 1979 Jan 8, 70(2), 183 - 94 Studies in heterochromatin DNA: accessibility of late replicating heterochromatin DNA in chromatin to micrococcal nuclease digestion; Kuo MT; Heterochromatin DNA in cactus mouse (Peromyscus eremicus) replicates in the late S phase of cell cycle . A method of obtaining cells which contain DNA preferentially labeled at heterochromatic areas by a pulse-labeling of late replicating DNA is described . When the nuclei of P . eremicus cells containing radioactively labeled DNA in heterochromatin were digested with micrococcal nuclease and the resultant nucleosomal DNA was separated by gel electrophoresis, it was found that the repeat length of nucleosomal DNA in the heterochromatin DNA is not different from that of the bulk of the genomic DNA . Furthermore, there was no significant difference in the accessibility to digestion by micrococcal nuclease between the late replicating heterochromatin DNA and the total DNA under our digestion conditions . Two dimensional gel electrophoresis patterns of nucleosomal DNAs isolated from micrococcal nuclease digested nuclei from P . eremicus, P . collatus, and P . crinitus cells in culture were very similar . Cytogenetic data showed that these three species are different in heterochromatin but similar in euchromatin. J Bacteriol, 1979 Jan, 137(1), 69 - 72 Phosphate transport in arsenate-resistant mutants of Micrococcus lysodeikticus; Alfasi H et al.; Two types of arsenate-resistant mutants of Micrococcus lysodeikticus were found: (i) mutants that grow in the presence of 10 mM but not 1 mM phosphate (Pi) with low uptake rate for Pi and arsenate, and (ii) mutants able to grow in the presence of 10 mM and 1 mM Pi, with a near-normal uptake rate for Pi but a low one for arsenate . The Km values for Pi transport and the Ki values for its competitive inhibition by arsenate were similar for the mutants and the wild type . Similar to the wild type, the mutants also accumulated Pi to high concentrations . In all strains, the transport of Pi was subject to repression by Pi . Mutant types showed lower Vmax but unaltered Km values for arsenate as compared to the wild type, and they accumulated arsenate to markedly lower levels . The results suggest a two-component transport system common to Pi and arsenate. Folia Biol (Praha), 1979, 25(6), 380 - 8 Regular character of chromatin degradation in lymphoid tissues after treatment with biological alkylating agents in vivo; Matyasova J et al.; The aim of the present study was to reassume the chromatin changes occurring in lymphoid tissues of mice treated with alkylating agents of the nitrogen-mustard type in relation to recent evidence on the nucleosomal organization of chromatin and to our new data on the regular character of chromatin degradation in lymphoid tissues of irradiated mice . DNA was isolated from nuclei at various intervals (1-18 h) after treatment of mice and subjected to gel electrophoresis in polyacrylamide gels . Thymus chromatin from treated mice has been shown to degrade in a regular fashion and to yield discrete DNA fragments, resembling those that originate in lymphoid tissues of irradiated mice or in thymus nuclei digested with micrococcal nuclease in vitro . With increasing interval after treatment higher amounts of smaller DNA fragments appear . Chromatin in spleen cells responds to treatment in a similar way, whilst no degradation in vivo takes place in liver chromatin . Chromatin of LS/BL lymphosarcoma cells in mice treated with alkylating agents or with irradiation suffers from a similar regular degradation . The results stress the significance of the action of liberated or activated endogenous nuclease(s) in the development of chromatin damage in lymphoid cells after treatment with alkylating agents. Acta Biochim Pol, 1979, 26(4), 417 - 21 Isolation of chromatin subcore particles by chromatography on Biogel 1.5 m; Staron K et al.; The method is described for separation and purification by chromatography on Biogel 1.5 m of subnucleosomal nucleoprotein particles obtained by extensive digestion of calf thymus nuclei with micrococcal nuclease. Nucleic Acids Res, 1979, 6(6), 2339 - 53 DNA-binding properties of the major core protein of adenovirus 2; Black BC et al.; The major adenovirus core protein (P.VII) binds to various species of duplex and single-stranded DNA molecules as a linear function of P.VII concentration . P.VII progressively condenses 32S Ad2 DNA into rapidly sedimenting forms having an S value of around 2,280 . P.VII does not coat DNA like cytochrome C, instead DNA-protein beads are visualized in the electron microscope at low protein concentration . These beads appear to interact forming larger structures and at high P.VII concentrations the DNA molecule becomes highly compacted . Analysis of DNA fragments formed after digestion of P.VII-DNA complexes and isolated cores with micrococcal nuclease suggest that the organization of the DNA in the two structures is essentially identical . The initial P.VII and DNA interaction is sensitive to both ionic and hydrophobic environments, whereas the in vitro DNA-P.VII complexes are extremely stable and are not disrupted in the presence of 3 M NaCl, 1% sarcosyl or 5% deoxycholate . Properties of these in vitro DNA-protein VII complexes share striking similarities to isolated viral core particles. Nucleic Acids Res, 1979, 6(5), 1843 - 62 The effects of salt concentration and H-1 depletion on the digestion of calf thymus chromatin by micrococcal nuclease; Weischet WO et al.; We have removed histone H1 specifically from calf thymus nuclei by low pH treatment, and studied the digestion of such nuclei in comparison with undepleted nuclei . By a number of criteria the nuclei do not appear damaged . The DNA repeat-length in nuclear chromatin is found to be the same (192 +/- 4 bp) in the presence or absence of H1 . These experiments demonstrate that the core histone complex of H2A, H2B, H3, and H4 can itself protect DNA sequences as long as 168 bp from nuclease . Our interpretation is that this represents an important structural element in chromatin, carrying two full turns of superhelical DNA . Depending on conditions of digestion this 168 bp fragment may be metastable and is normally rapidly converted by exonucleolytic trimming to the well-known "core-particle" containing 145 bp . Larger stable DNA fragments observed indigestion of H-1 depleted nuclei appear to arise from oligomers assembled from 168 bp cores in close contact exhibiting trimming of 0-20 bp at the ends . Electrophorograms of undepleted nuclear digests reveal oligomer bands in several size classes, each corresponding to one or more combinations of 168 bp particles, H1-protected spacers of about 20 bp length, and particles with ends trimmed to varying degrees. Nucleic Acids Res, 1979, 6(5), 1805 - 16 Nucleosome cores reconstituted from poly (dA-dT) and the octamer of histones; Rhodes D; In this paper we describe a detailed investigation of the reconstitution of nucleosome cores from poly (dA-dT) and the octamer of histones . We also attempted the reconstitution from the copolymers poly dA.poly dT, poly dG.poly dC and poly (dG-dC) . The repeat of the reconstituted chromatin fibre is discussed . The micrococcal nuclease released poly (dA-dT) core particle is found to contain a considerably narrower DNA size distribution that of the native random DNA nucleosome core (12) . In addition we have succeeded in obtaining small crystals of the poly (dA-dT) nucleosome core . The DNAase I digestion pattern of the poly (dA-dT) containing nucleosome core is presented . The periodicity of DNAase I cutting sites is found to be about 10.5 bases and is similar to that of the native nucleosome core (12, 13). Nucleic Acids Res, 1979 Jan, 6(1), 359 - 70 The influence of chromatin structure on the distribution of DNA repair synthesis studied by nuclease digestion; Bodell WJ et al.; The influence of chromatin structure on the distribution of DNA repair synthesis was studied by enzymatic digestion of "repair labeled" nuclei of mouse mammary cells: "repair labeled" nuclei were isolated from pregnancy mammary tissue fragments, treated in vitro with methylmethanesulfonate (MMS) or methylnitrosourea (MNU), and pulse-labeled with 3H-thymidine in the presence of hydroxyurea in the culture medium . Micrococcal nuclease digestion of "repair labeled" nuclei indicates that at early hours after treatment with the alkylating agents 70-80% of the total repair synthesis is located in the linker portion of the nucleosome . However, 6-12 hours after treatment DNA repair synthesis is more evenly distributed throughout the core and linker portion of the nucleosome . "Repair labeled" mammary cell nuclei were also digested with DNase I under conditions selective for transcriptionally active chromatin . A two-fold higher level of repair synthesis was found in the transcriptionally active chromatin of "repair labeled" nuclei isolated from MMS or MNU treated mammary fragments, pulse-labeled at different times after treatment . The results indicate that structural constitution of the chromatin may influence the distribution of DNA repair synthesis both at the nucleosome level, and at higher levels of chromatin organization . This may be due to 1) nonrandom base alkylation in chromatin or 2) areas in chromatin with increased accessibility for the repair enzymes to the alkylated bases. Nucleic Acids Res, 1979 Jan, 6(1), 259 - 74 Multiacetylated forms of H4 are found in a putative transcriptionally competent chromatin fraction from trout testis; Levy-Wilson B et al.; We have examined the distribution of acetylated histones derived from various trout testis chromatin fractions of different composition . Our results indicate that a chromatin fraction, preferentially solubilized by micrococcal nuclease, containing the bulk of the HMG proteins and similar to a fraction released from intact trout nuclei and previously shown to be enriched in transcribed DNA sequences also possesses high levels of multiacetylated species of H4 . Histones 2A, 2B and 3 are also acetylated in this particular chromatin fraction . Monoacetylated species of the 4 inner nucleosomal histones appear to be characteristic of the nucleohistone portion of trout testis chromatin. Nucleic Acids Res, 1979 Jan, 6(1), 167 - 79 Studies on the association of the high mobility group non-histone chromatin proteins with isolated nucleosomes; Mathew CG et al.; Nucleosomes have been isolated from rabbit thymus by sucrose gradient centrifugation, and their high mobility group (HMG) protein content analysed by electrophoresis on polyacrylamide gels . The results suggest that proteins HMG 14 and HMG 17 are associated with the core particle of the nucleosome, and that there are two or more sub-populations of both HMG 1 and HMG 2 molecules . One sub-population appears to be fairly tightly bound to the nucleosome, while another is rapidly released from the chromatin by digestion with micrococcal nuclease . The latter fraction may participate in a higher order folding of the nucleosomes. Antonie Van Leeuwenhoek, 1979, 45(2), 177 - 84 Rate of drying and the survival of microorganisms; Antheunisse J et al.; The survival rate of cells of the genera Arthrobacter, Pseudomonas, Mycobacterium, Escherichia, Micrococcus and Saccharomyces when counted immediately after fast or slow drying (20 minutes and 24 hours, respectively) was rather similar . However, after prolonged periods of dry storage, the number of viable cells after slow drying was much higher as compared with the rapidly dried cells . Investigations with Escherichia coli demonstrated this phenomenon only when more than about 8 mg of water per 10(8) cells was available on a filter paper disc . In order to obtain optimum resistance to water loss the dessication period of 0.025 ml of suspension of E . coli must be longer than 13 hours. Med Pediatr Oncol, 1979, 7(4), 309 - 14 Micrococcus luteus pneumonia: a case report and review of the literature; Souhami L et al.; The clinical course of a 69-year-old male with acute myelogenous leukemia is described who, while extremely leukopenic (less than 100 neutrophils/microliter) from chemotherapy, developed a cavitating pneumonia due to a gram-positive coccus, Micrococcus luteus . Aggressive antibiotic management and attainment of complete remission of his leukemia resulted in a successful outcome . A review of the literature regarding the pathogenicity of this organism and, in particular, its occurrence as a cause of pneumonia is presented. Swed Dent J, 1979, 3(2), 63 - 7 Lysozyme activity in saliva from children with various degree of gingivitis; Modeer T et al.; The lysozyme activity was determined in paraffin stimulated whole saliva from 51 randomly selected children . The average age was 6.5 years . The children were divided into four groups according to their degree of gingival inflammation . An agardiffusion method was used with Micrococcus lysodeikticus as indicator of the lysozyme activity . The mean value of the lysozyme activity was determined to 48.4 microgram/ml . In the non-inflamed group the enzyme activity was 8.7 microgram/ml, whereas it was lower, 31.5 microgram/ml, in children with inflamed gingiva . The correlation coefficient (p less than 0.05) suggest that there is a negative relationship between saliva lysozyme and the degree of gingival inflammation . Furthermore this study indicates that lysozyme acts as one of the resistant-factors against gingival inflammation in young individuals. Mikrobiyol Bul, 1979 Jan, 13(1), 63 - 71 {The effect of sodium polyanethol sulfonate (SPS) on the growth of bacteria in blood cultures}; Baykal M; The effect of SPS on growth of bacteria in blood cultures were studied . For that reason, 752 blood cultures (in media with and without SPS) were detected and found that SPS may help to growth only micrococcus species. Nucleic Acids Symp Ser, 1979, (6), s163 - 6 Photobinding of 8-methoxypsoralen and changes in nuclease digestability of replicating SV40 chromatin; Oda T et al.; To analyze the structure of the replicating regions of simian virus 40 nucleoprotein complex (SV40 chromatin), photochemical binding of 8-methoxypsoralen (8-MOP) and changes in digestability with micrococcal nuclease were studied . 8-MOP bound preferentially to the linker DNA of nucleosomes and strongly inhibited nuclease digestion . Nuclease digestability of newly synthesized DNA in the replicating chromatin was markedly increased, but it was inhibited in the early time of nuclease reaction by photobinding of 8-MOP . The data suggest that the replicating regions of chromatin are more exposed than the bulk of mature chromatin. Z Allg Mikrobiol, 1979, 19(7), 489 - 95 Studies on the substrate specificity of the DNA methylase activity from Escherichia coli K-12; Schmidt A et al.; A partially purified extract of DNA methylases from E . coli K-12 containing DNA-adenine as well as DNA-cytosine methylase activities has been examined with respect to different DNA species as substrates . The results show that the natural content of 6-MAP) in the applied DNA represses the DNA-adenine methylase activity . On the other hand, 5-MC, already present in the substrate does not influence the activity of the DNA-cytosine methylase . DNA from Micrococcus radiodurans, which is completely free of methylated bases served as comparison . Since netropsin preferentially binds to AT-rich regions of DNA, the influence of this oligopeptide antibiotic on the methylation of DNA was investigated . As expected the antibiotic predominantly inhibits adenine methylation of DNA . The degree of inhibition depends on the molar ratio of netropsin to DNA phosphate. Microbiol Immunol, 1979, 23(8), 717 - 26 Cell wall-bridge maintaining three dimensional structure of cell packets formed by the localized suppression of cell separation of a Micrococcus lysodeikticus (luteus) mutant; Monodane T et al.; Cell packets of Micrococcus lysodeikticus (luteus) mutant strain MT grown in medium supplemented with trypsin consisted of a tetrad as the unit structure . An interstice was observed between the unit-tetrads, and a three dimensional structure of cell packets was maintained by the cell wall-bridge along the rim of the cell packets which linked each unit-tetrad . This unique structure of strain MT cell packets seemed to occur when the cell separation was suppressed locally, i.e., when the cross wall inside the initial site of cell separation was cut off, while the wall outside the initial site of separation was not cut off but remained as a joint of the daughter cells . The mechanism of cell wall-bridge formation is discussed in connection with cell separation. Biochim Biophys Acta, 1978 Dec 21, 521(2), 493 - 501 Effect of ethidium bromide on the digestion of chromatin DNA with micrococcal nuclease; Jerzmanowski A et al.; Intercalation of ethidium bromide into DNA influences the rate of its digestion with micrococcal nuclease in opposite directions depending on whether it is free DNA or DNA in chromatin . In the case of free DNA the binding of ethidium bromide, starting from a very low concentration, results in the inhibition of the rate of digestion (increasing constantly with the increase of the ethidium bromide/nucleotide ratio) . In contrast to free DNA the digestion rate as well as the overall amount of nuclease susceptible DNA is increased upon ethidium bromide binding to chromatin, with maximum enhancement around the saturation of intercalation sites . The saturation of intercalation sites in chromatin leads also to the disappearance of the typical micrococcal nuclease digestion pattern of DNA upon gel electrophoresis . Instead, a random cleavage pattern is observed . These data indicate that partial unwinding of chromatin DNA by ethidium bromide results in unmasking new sites for nuclease action . Interpretation of this finding in terms of the nucleosomal structure of chromatin and the mode of ethidium bromide binding to chromatin DNA indicates that newly unmasked sites are localized within the core particle DNA. Chromosoma, 1978 Dec 6, 69(3), 363 - 72 Higher order structure in metaphase chromosomes . I . The 250 A fiber; Rattner JB et al.; Metaphase chromosomes released from cells in the presence of Joklik's suspension media by vortex-mixing with 0.5 mm glass beads have been analyzed by electron microscopy . In these preparations the chromosomes are composed of series of loops (200-300 A in diameter) which are, in turn, composed of closely-apposed arrays of nucleosomes . Negative-staining of these preparations has allowed the identification of several distinct patterns within the loop which appear to arise from variations in nucleosome packing . Analogous patterns are also observed in chromatin fragments generated by brief micrococcal nuclease digestion . From these data we have deduced certain features of nucleosome-nucleosome interactions in higher-ordered chromatin fibers. Chromosoma, 1978 Dec 6, 69(3), 331 - 8 Responses of mammalian metaphase chromosomes to endonuclease digestion; Sahasrabuddhe CG et al.; Digestion of fixed metaphase chromosomes by endonucleases (micrococcal nuclease and DNase II) under optimal digestion conditions followed by Giemsa staining produces sharp banding patterns identical to G-bands . In 3H-thymidine labeled, synchronized metaphase cells of the chinese hamster (CHO line), the band induction is accompanied by the removal of DNA . The single strand specific nuclease S1 and DNase I do not produce such banding patterns. Biokhimiia, 1978 Dec, 43(12), 2163 - 74 {Has the respiratory chain of Micrococcus lysodeiktocus any redox components on the outer surface of cytomembrane?}; Tikhonova GV et al.; M . lysodeikticus protoplasts have catalyzed the reduction of 5.10(-4) M ferricianide by endogenous substrates if the respiratory chain is inhibited by cyanide or anaerobiosis . A disturbance of the protoplast permeability by osmotic shock or Triton X-100 treatment resulted in the decrease of the endogenous ferricianide reduction rate and in simultaneous stimulation of malate ferricianide reductase activity in dehydrogenase site of the inner membrane surface . Reactivation of endogenous ferricianide reduction by protoplasts and the loss of malate stimulating activity were observed in hyperosmotic medium . Unlike malate oxidation by osmotically shocked protoplasts, endogenous protoplast repiration was resistant to ferricianide 5.10(-4) M) . The latter, being added to protoplasts, induced the oxidation of anaerobically reduced cytochromes b556+560, and it practically did not affect cytochromes c552 and a601 . The data obtained suggest that at least one of the respiratory chain components is arranged on the outer side of the protoplast membrane . This component is probably located in the cytochrome region . The results obtained confirm the hypothesis on transmembrane organization of the respiratory chain in M . lysodeikticus. Chem Biol Interact, 1978 Dec, 23(3), 387 - 97 Evidence for alteration of the membrane-bound ribosomes in Micrococcus luteus cells exposed to lead; Barrow W et al.; Micrococcus luteus cell exposed to PB(NO3)2 contained cytosol ribosomal particles and disaggregated membranal ribosomal particles as determined by ultracentirifugation and spectral studies . Approx . 60% of the membrane ribosome fraction from lead exposed cells had a sedimentation value of 8.4S . Cytosol ribosomes from lead exposed cells as well as membranal and cytosol ribosomes from control cells were comparable by their contents of predominantly the 70S type with the 50S and 100S present in relatively small amounts . The lead content of the 8.4S component was more than 200 times higher than the components with higher sedimentation coefficients from lead exposed cells and approc . 650 times more than that of control cell ribosomes . The cells exposed to lead, however, showed no adverse effects from the lead in respect to their growth rates and cellular yields . These results indicate that lead is interacting only at specific sites of the membrane and is inducing events initiated only in strategic cellular regions . These data further substantiate that subtle changes do occur in lead exposed cells that show no obvious effects . It is assumed that these 'minor' alterations are, in toto, biologically significant. Aktuelle Gerontol, 1978 Dec, 8(12), 675 - 80 Age-dependent structural changes in human neuronal chromatin; Ermini M et al.; After partial digestion with micrococcal nuclease, DNA was extracted from nuclei of cerebral cortex neurons from young (23--36 y.) and old (78--85 y.) humans . The DNA fragments were subjected to gel electrophoresis, and their base-pair content determined . The nucleosomal DNA repeat length was found to increase from 170 (+/- 18) base-pairs in the young group to 199 (+/- 8) base-pairs in the old group . This increase of 29 base-pairs appears to be confined to the linker region of the nucleosomal DNA, since the core-DNA was always found to contain approx . 140 base-pairs . In addition, the amount of nuclear DNA digested by the micrococcal nuclease was observed to vary with age: after 30 min . of incubation at 37 degrees C hydrolysis of up to 80% of the nuclear DNA in the young but only up to 60% in the old neuronal nuclei was achieved . The age-dependent increase in chromosomal DNA repeat length is a direct proof of alterations in the basic chromatin structure with aging . It cannot be decided, however, whether the change in DNA digestibility is dependent on alterations of the chromatin basic structure, its superstructure, or both. Appl Environ Microbiol, 1978 Dec, 36(6), 966 - 8 Silica gel media for isolating and studying bacteria under hydrostatic pressure; Dietz AS et al.; Individual colonies of micrococcus euryhalis and of a marine bacterial isolate were grown in pour tubes under hydrostatic pressure . The medium was prepared in a silica sol, and gelation was effected at 4 degrees C by addition of salts to achieve concentrations found in seawater. Biochim Biophys Acta, 1978 Nov 22, 531(2), 179 - 86 The positional specificity of a desaturase in the psychrophilic bacterium Micrococcus cryophilus (ATCC 15174); Russell NJ; The positional specificity of the desaturase activity in the psychrophilic bacterium Micrococcus cryophilus (ATCC 15174) is shown to be delta9 . The desaturase is inhibited by sterculic acid . Small amounts of delta8, delta10 and delta11 isomers are present . The implications of these findings for fatty acid metabolism in M . cryophilus are discussed . It is suggested that the temperature-dependent chain length change, known to occur in the phospholipid fatty acids of this bacterium, is not mediated by either a temperature-dependent change in desaturase substrate specificity or the induction of new desaturase enzymes with novel positional specificity . It is concluded that the control by temperature of fatty acid chain length is mediated by either a temperature-dependent change in the products of fatty acid synthetase or a temperature-sensitive palmitate elongase. Biochemistry, 1978 Nov 14, 17(23), 4908 - 16 Nucleosome structure of Xenopus oocyte amplified ribosomal genes; Reeves R; The chromatin subunit or nucleosome structure of the amplified, extrachromosomal, ribosomal genes of oocytes of the amphibian Xenopus laevis has been investigated during stages of growth when these genes are markedly changing their rates of transcriptional activity . Nucleic acid hybridization studies involving micrococcal nuclease derived monomer nucleosome DNA fragments and purified ribosomal RNAs indicate that the apparent degree of accessibility of the ribosomal genes to short-term nuclease hydrolysis varies as a function of the rate of ribosomal RNA (rRNA) transcription . However, at no stage during oocyte development are all of the amplified ribosomal genes completely accessible to nuclease hydrolysis, even in those stages with maximal rates of rRNA transcriptional activity . These results suggest that the transcriptionally active ribosomal genes of oocytes are partially, or perhaps transiently, associated with histones in the form of nuclease releasable nucleosomes but that the degree of this association may change with varying rates of rRNA synthesis . Additionally, the present data indicate that the average size of the double-stranded ribosomal DNA associated with monomer nucleosomes is the same (about 200 base pairs) in all of the oocyte stages examined regardless of the rates of rRNA synthesis in these stages. Isr J Med Sci, 1978 Nov, 14(11), 1116 - 23 Absence of functional beta-globin messenger RNA in Kurdish Jews with beta0-thalassemia; Di Segni G et al.; Human globin messenger RNA was isolated from reticulocytes of four Jewish patients of Kurdish origin with homozygous beta0-thalassemia . On translation in the wheat-germ cell-free system, messenger RNA from these patients directed extensive synthesis of alpha- and gamma-globin chains, but synthesis of beta-globin chains was not detectable . In contrast, nonthalassemic human globin messenger RNA directed the synthesis of essentially equimolar amounts of alpha- and beta-globin . The patterns of globin synthesized by beta0-thalassemic messenger RNA in the cell-free system were virtually identical to the patterns of globin synthesized in peripheral blood cells of these patients . beta0-thalassemic messenger RNA similarly failed to direct any detectable beta-globin synthesis in a micrococcal nuclease-treated rabbit reticulocyte lysate, even in the presence of an excess of purified eukaryotic initiation factor 2 . These results strongly suggest that functional messenger RNA for beta-globin chains is absent in Kurdish Jews with homozygous beta0-thalassemia. Mikrobiologiia, 1978 Nov-Dec, 47(6), 1037 - 43 {Deuterated membranes of Micrococcus lysodeikticus: production and several biochemical properties}; Eremin VA et al.; A technique has been elaborated for preparation of deuterated membranes from deuterated cells of Micrococcus lysodeikticus containing 85--90% of deuterium according to the data of IR and PMR spectroscopy . Normal lysis of the deuterated cells of M . lysodeikticus requires a concentration of lysozyme which is eight times higher than for usual cells (8 mg per 1 g of wet deuterated cells) and an addition of the lytic enzymes E-2 (2 mg per 1 g of wet deuterated cells) . Preparations of deuterated membranes purified from ribosomes and proteins can be obtained by treating of the lysate with RNAase and washing in 0.5 M NaCl . The purity of the deuterated membranes was evaluated by the evidence of electron microscopy, IR spectra and enzyme activities . After hydrogen atoms were substituted by deuterium, the secondary structure of the total membrane protein, the ratio between the activities of the respiratory chain enzymes, and the relative content of the lipid and protein components of the deuterated membranes remain at the same level as in the protonated ones. Hoppe Seylers Z Physiol Chem, 1978 Nov, 359(11), 1579 - 89 Well-defined insoluble primers for the enzymatic synthesis of oligo- and polynucleotides; Koster H et al.; Two methods are described by which primer molecules like UpU and oligodeoxythymidylates can be coupled with high efficiency to an insoluble polymer, like hydroxypropylated Sephadex G-50, by one covalent linkage . In one procedure aliphatic dicarboxylic dichlorides (e.g . adipoyl dichloride) are used to serve as spacers of variable length and for anchoring the primer molecule UpU . The other method involves pU as an anchor for (pdT)3 and (pdT)6, which are coupled to the polymer using condensation reactions with 2,4,6-triisopropylphenylsulfonyl chloride . In both cases the homogeneous primer molecules are bound specifically to the polymer . The insoluble primers are tested for their priming efficiency using polynucleotide nucleotidyltransferase from Micrococcus luteus and DNA nucleotidylexotransferase from calf thymus . The primers and synthesized polynucleotides can be cleaved from the polymer under conditions which are not damaging to ribo- and deoxyribopolynucleotides. Br J Cancer, 1978 Nov, 38(5), 599 - 605 Influence of micrococcus, BCG and related polysaccharides on the proliferation of the L1210 leukaemia; Verloes R et al.; A comparative study of the effects of BCG, Micrococcus lysodeikticus, and a series of structurally related polysaccharides (complement triggers) on the non-specific and specific immune resistance against L1210 lymphoid leukaemia was carried out and commented on . In contrast with authors of earlier reports, we were unable to generate any effective non-specific or specific immunotherapy after the graft of 10(4) leukaemic cells to 8--10-week-old CDF1 mice . However, when mice were prevaccinated with irradiated (8 krad X-rays) cultured cells combined with 1 mg of bacterium or polysaccharide one month before grafting 10(4) cells, they were given an immunoprotection that was more pronounced with the i.p . than with the i.v . route . Prevaccinated mice were afforded a stronger immunoprotection when boosted repeatedly with 1mg injections of bacterium or polysaccharide after tumour challenge. Cancer Res, 1978 Nov, 38(11 Pt 2), 4229 - 32 Comparison between different forms of estrogen cytosol receptor and the nuclear receptor extracted by micrococcal nuclease; Rochefort H et al.; As an approach to the mechanism of the nuclear translocation of estrogen receptor, the estradiol nuclear receptor (RN) of lamb endometrium was extracted with micrococcal nuclease at 2--4 degrees and compared to the "native" 8S and to the Ca2+-transformed cytosol receptors . After extensive digestion of chromatin, giving up to 10% perchloric acid-soluble DNA and a majority of nucleosome monomers, up to 80% of the RN was extracted and under low ionic strength . This RN was found to be completely different from the partially proteolyzed Ca2+-transformed cytosol receptor . It migrated with a sedimentation constant of 4 and 6 S . The Stokes radius of the predominant form as determined by ACA 34 chromatography was 5.3 nm . The calculated apparent molecular weights were 130,000 and 90,000, respectively . The RN was able to bind DNA and was eluted from a diethylaminoethyl cellulose column at 0.23 and 0.30 M KCl . We conclude that the mechanism proposed by Puca et al., according to which the Ca2+-transformed cytosol receptor is split by a Ca2+ receptor-transforming factor into a smaller form able to cross the nuclear membrane, is very unlikely. Nucleic Acids Res, 1978 Nov, 5(11), 4155 - 63 Partial purification of transcriptionally active nucleosomes from trout testis cells; Levy B et al.; Mononucleosomes (MN1) enriched in structural non-histone proteins and transcribed DNA sequences were obtained by limited digestion of trout testis nuclei with micrococcal nuclease followed by selective solubilization in 0.1 M NaCl . These monosomes consist of the four inner histones plus stoichiometric amounts of the non-histone protein H6, of the HMG group, complexed with 140 base pairs of DNA . Hybridization experiments indicate that MN1 DNA is enriched in sequences complementary to cytoplasmic polyadenylated RNA. Nucleic Acids Res, 1978 Nov, 5(11), 4343 - 54 Incorporation of labelled degradation products of radioactive thymine into non DNA material; Anderson ML; When thymine auxotrophs are grown in the presence of methyl labelled {3H} or {14C} thymine which has been stored at 4 degrees C, two classes of material are labelled which are not DNA . One class sediments on neutral sucrose gradients with spontaneously single stranded Okazaki pieces, is unstable in alkali, migrates on alkaline gels as very small material and is digested by ribonucleases and micrococcal nuclease, but not by DNAase I . This class is presumably RNA . The second class sediments more slowly on both neutral and alkaline sucrose gradients than Okazaki pieces, but co-migrates on alkaline gels with DNA whose size is between 700 and 4000 nucleotides . It is not digested by alkali, ribonucleases or deoxyribonucleases . Its identity is unknown . The proportion of the total incorporated counts in these two classes depends on the time of storage of the thymine and is already sufficient to interfere with certain types of experiments when the thymine is only a few weeks old . Thymine is easily purified by paper chromatography and this purified thymine does not label the two non DNA classes of material . It is recommended that radioactive thymine be purified in this way before use. Proc Natl Acad Sci U S A, 1978 Nov, 75(11), 5525 - 8 Topographic study of the cell surface of micrococcus radiodurans; Baumeister W et al.; The paracrystalline outer membraneous layer (HPI layer) of Micrococcus radiodurans has been investigated by negative- and positive-staining electron microscopy and subsequent digital image processing . The subunit structure of the major HPI layer protein complex and the lipid-protein distribution in the plane of the membrane have been determined . The HPI layer was found to be highly asymmetric in a transmembrane direction, with the major protein complex only partly penetrating into a lipid-containing backing layer intimately associated with it. Z Naturforsch {C}, 1978 Nov-Dec, 33(11-12), 948 - 54 {Protein synthesis with cell extracts of Micrococcus radiodurans (author's transl)}; Widmann A et al.; Pure active ribosomes of cells of Micrococcus radiodurans could be obtained when cultivated in trypton, glucose and nutrient broth by adding natrium citrate . The optimal conditions for a cell-free protein synthesis were investigated at the (polyuridylic acid) dependent polyphenylalanine synthesis . When exchanging ribosomes and S100-fractions with the corresponding fractions of E . coli, we found that the enzyme fractions of M . radiodurans extremely inhibit the ribosomal activity . The incorporation rates in the cell-free system of M . radiodurans yield, at comparable conditions, in relation to E . coli under 10%. Cell, 1978 Nov, 15(3), 955 - 67 Mobility of histones on the chromosome of simian virus 40; Beard P; Linear simian virus 40 (SV40) chromosomes were prepared by Eco R1 nuclease cleavage of the circular SV40 chromosomes released from virions with dithiothreitol at pH 9,8 . Chromatin-DNA hybrids were constructed with segments of 3H-labeled, naked SV40 DNA covalently joined via the Eco R1-generated cohesive ends to segments of linear SV40 chromosome . Upon incubation of chromatin-DNA hybrids at 37 degrees C and moderate ionic strength, histones migrated onto the labeled DNA while retaining the nucleosome structure . This was shown first, by the pattern of micrococcal nuclease digestion of labeled DNA; second by nitrocellulose filter binding of labeled DNA after redigestion of the chromatin-DNA hybrids with Eco R1; and third, by examination of chromatin-DNA hybrids in the electron microscope . Migration was slow, being apparent after several hours . Parallel experiments in which naked DNA and chromosomes were mixed without joining showed no transfer of nucleosomal histones between DNA molecules . The kinetics of Eco R1 cleavage of the DNA in virion-derived SV40 chromosomes are also consistent with the notion that nucleosomal histones, in the absence of other proteins, can move on DNA. J Biol Chem, 1978 Oct 25, 253(20), 7124 - 6 Stimulation of protein synthesis by hemin in extracts of Friend erythroleukemia cells; Dabney BJ et al.; Extracts prepared from Friend erythroleukemia cells were highly active in translating endogenous mRNA and a consistent 2-fold stimulation by hemin was observed . When extracts were treated with micrococcal nuclease and incorporation was dependent on exogenous globin mRNA, there was more significant stimulation by 37.5 micron hemin and greater than 10-fold stimulation by 75 or 150 micron hemin . The effects of hemin were not strikingly different in extracts of dimethyl-sulfoxide-induced or uninduced cells . The results could reflect an effect on initiation of protein synthesis analogous to that in rabbit reticulocytes. Mol Biol Rep, 1978 Oct 16, 4(3), 177 - 80 The effect of the messenger RNA concentration on the competitive inhibition of translation by cap-analogues; Asselbergs FA et al.; Inhibition of translation of several mRNA species in a micrococcal nuclease treated reticulocyte lysate by cap analogues was compared with the competition between two mRNAs . Inhibition characteristics were very similar, only complete mRNA molecules inhibited at concentrations 150 times lower than m7 G5'ppp5'G . The inhibition of mRNA translation by cap analogues could be neutralized by the addition of extra mRNA in a manner predicted from the competitive nature of the inhibition by cap analogues. Mol Biol Rep, 1978 Oct 16, 4(3), 149 - 52 Effects of chloramphenicol on the postreplication repair and sister recombinational DNA exchanges in ultraviolet-irradiated Micrococcus luteus; Tomilin NV et al.; The filling of about one third of postreplication DNA gaps in u.v.-irradiated Micrococcus luteus ATCC 4698 is blocked by chloramphenicol (CA) added just before irradiation . Addition of CA 15 min after u.v.-irradiation does not prevent the complete repair of the gaps . U.v.-sensitive M . luteus mutants (ML 6 and ML 15) are identified as defective in different steps of inducible postreplication DNA repair (PRR) . PRR in unexcising M . luteus strain G7 is accompanied by the transfer of about 20% of pyrimidine dimers from parental to daughter DNA strands, which indicates the existance of recombinational pathway of PRR . Recombinational PRR in M . luteus is not inhibited by CA. Biochim Biophys Acta, 1978 Oct 4, 512(3), 461 - 71 A new assay system of phospholipid exchange activities using concanavalin A in the separation of donor and acceptor liposomes; Sasaki T et al.; A new assay system of phospholipid exchange activities is described . The exchange activities were quantitated by measuring the stimulation of phospholipid transfer between two separate populations of liposomes, which contained, as the major constituents, phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol, sphingomyelin, and cholesterol in molar ratios of 6 :2 : 1: 1: 5 . One population of the liposomes was made reactive to concanavalin A by the incorporation of 1.8 mol% alpha-D-mannosyl-(1 leads to 3)-alpha-D-mannosyl-sn-1, 2-diglyceride from Micrococcus lysodeikticus . The concanavalin A-reactive liposomes, a phospholipid donor, were doubly labelled with {6-3H} galactosylglucosyl ceramide and that class of 32P-labelled phospholipids whose exchange was being measured . The 3H-labelled glycolipid served as a non-exchangeable reference marker . The other population of the liposomes, a phospholipid acceptor, was concanavalin A nonreactive . These two populations of liposomes were incubated with the cytosol protein of rat liver in a total volume of 0.2 ml . After the incubation, two different procedures were used to separate the two liposomal populations . In one procedure concanavalin A was added to agglutinate the reactive liposomes; the flocculated lectin . liposome complex was separated from the non-reactive liposomes by brief centrifugation . In the other procedure the reactive liposomes were trapped by binding to concanavalin A covalently coupled to Sepharose 2B; the complex was separated from the non-reactive liposomes by filtration through a filter paper under suction . In both assay procedures the amount of phospholipid transferred from the donor to the acceptor liposomes was calculated from the decrease of 32P/3H ratio of the concanavalin A-reactive liposomes during the incubation . By the assasy system it is possible to determine phosphatidylcholine and phosphatidylinositol exchange activities in 100 micrograms of rat liver cytosol protein. Biochemistry, 1978 Oct 3, 17(20), 4311 - 7 Sequence of a rabbit anti-Micrococcus lysodeikticus antibody light chain; Van Hoegaerden M et al.; The complete sequence of rabbit antibody light-chain L 120 has been elucidated . The antibody was raised against Micrococcus lysodeikticus bacteria and is specific for the external part of the cell wall . All protein used in this work was obtained from a single 50-mL bleeding . The variable region of L 120 is compared to 13 other sequences of chains of different specificities . The constant region of this b4 k chain is identical to that of two other constant regions published earlier . The general structure of the rabbit light chain is compatible with the three-dimensional folding proposed for human myeloma chains. Nucleic Acids Res, 1978 Oct, 5(10), 3523 - 47 Effect of histone acetylation on structure and in vitro transcription of chromatin; Mathis DJ et al.; n-Butyrate treatment of growing Hela cells produces a dramatic increase in the levels of histone acetylation . We have exploited this system to study the effect of histone acetylation on chromatin structure . Chromatin containing highly acetylated histones is more rapidly digested to acid-soluble material by DNase I, but not by micrococcal nuclease . The same pattern of nuclease sensitivity was exhibited by in vitro-assembled chromatin consisting of SV40 DNA Form I and the 2 M salt-extracted core histones from butyrate-treated cells . Using this very defined system, it was possible to demonstrate that acetylated nucleosomes do not have a greatly diminished stability . Stability was measured in terms of exhange of histone cores onto competing naked DNA or sliding of histone cores along ligated naked DNA . Finally, it was shown that acetylated nucleosomes are efficient inhibitors of in vitro RNA synthesis by the E . coli holoenzyme as well as by the mammalian polymerases A and B. Eur J Biochem, 1978 Oct, 90(2), 331 - 6 Manipulation of phospholipid composition of membranes with the aid of lipid exchange proteins . Incorporation of phosphatidylcholine into protoplasts of Micrococcus lysodeikticus; Barsukov LI et al.; Incubation of Micrococcus lysodeikticus protoplasts with phosphatidylcholine liposomes and rat liver exchange proteins (pH 5.1 supernatant fraction) resulted in replacement of about one half of the bacterial total phospholipids by phosphatidylcholine . Protoplasts modified by phosphatidylcholine showed a decreased rate of oxidation of exogenous substrates (NADH, malate) and decreased ferricyanide reductase activity as compared to the initial protoplasts . At the same time incorporation of phosphatidylcholine had no influence on the level of endogeneous respiration . Protoplasts modified by phosphatidylcholine were osmotically more stable than the initial protoplasts . After osmotic lysis of the phosphatidylcholine protoplasts their NADH (malate) oxidase and ferricyanide reductase activities were restored . Incorporation of phosphatidylcholine into membrane ghosts, obtained by osmotic rupture of the initial protoplasts had only small if any effect on the malate and NADH oxidase and dehydrogenase activities . It is concluded that phosphatidylcholine in incorporated predominantly into the outer part of cytoplasmic membrane and that proteinmediated transfer of phosphatidylcholine results in restoration of the permeability barrier due to repair of local defects in the initial protoplast membrane. J Cell Biol, 1978 Oct, 79(1), 97 - 109 Fractionation of nucleosomes by salt elution from micrococcal nuclease-digested nuclei; Sanders MM; The solubilization of nucleosomes and histone H1 with increasing concentrations of NaCl has been investigated in rat liver nuclei that had been digested with micrococcal nuclease under conditions that did not substantially alter morphological properties with respect to differences in the extent of chromatin condensation . The pattern of nucleosome and H1 solubilization was gradual and noncoordinate and at least three different types of nucleosome packing interactions could be distinguished from the pattern . A class of nucleosomes containing 13--17% of the DNA and comprising the chromatin structures most available for micrococcal nuclease attack was eluted by 0.2 M NaCl . This fraction was solubilized with an acid-soluble protein of apparent molecular weight of 20,000 daltons and no histone H1 . It differed from the nucleosomes released at higher NaCl concentrations in content of nonhistone chromosomal proteins . 40--60% of the nucleosomes were released by 0.3 M NaCl with 30% of the total nuclear histone H1 bound . The remaining nucleosomes and H1 were solublized by 0.4 M or 0.6 M NaCl . H1 was not nucleosome bound at these ionic strengths, and these fractions contained, respectively, 1.5 and 1.8 times more H1 per nucleosome than the population released by 0.3 M NaCl . These fractions contained the DNA least available for micrococcal nuclease attach . The strikingly different macromolecular composition, availability for nuclease digestion, and strength of the packing interactions of the nucleosomes released by 0.2 M NaCl suggest that this population is involved in a special function. Proc Natl Acad Sci U S A, 1978 Oct, 75(10), 4759 - 63 Circular dichroism analysis of mononucleosome DNA conformation; Cowman MK et al.; Mononucleosomes were isolated from micrococcal nuclease digests of chicken erythrocyte nuclei . The circular dichroism properties of mononucleosome preparations, differing in average DNA length and in H1 and H5 content, demonstrate that the spectrum of chromatin is due only to the complete structure of its repeating subunits . The nucleoprotein spectra are all altered relative to protein-free DNA by the emergence of a single negative band at 275 nm, similar to the band observed for psi DNA . The intensity of the psi-type band depends on the proportion of DNA condensed in a specific manner . The psi-type band is proposed to be due to the compact DNA tertiary structure; i.e., the manner in which the DNA is wound around the histone core allowing interactions between adjacent turns of the superhelix . This interpretation attributes changes and variability in nucleoprotein circular dichroism spectra under different experimental conditions to alterations in DNA tertiary structure rather than secondary structure. Proc Natl Acad Sci U S A, 1978 Oct, 75(10), 4868 - 72 O4-(5'-uridylyl)tyrosine is the bond between the genome-linked protein and the RNA of poliovirus; Rothberg PG et al.; Virion RNA of poliovirus type 1 has been analyzed for the linkage between genome-protein VPg and the polyribonucleotide chain . Hydrolysis of the linkage with acid or alkali and enzymatic degradation lead to the conclusion that the bond is neither a phosphodiester such as nucleotidyl-(P-O)-serine (or threonine) nor a phosphoramidate such as nucleotidyl-(P-N)-amino acid . VPg-RNA can be iodinated by the Bolton and Hunter reagent {iodinated 3-(4-hydroxyphenyl)propionic acid N-hydroxysuccinimide ester} but not by the chloramine-T or lactoperoxidase procedures, an observation suggesting that VPg does not contain accessible tyrosine . However, VPg can be labeled with {3H}tyrosine in vivo . Hydrolysis of VPg-{32P}pUp with 5.6 M HCl at 110 degrees yielded 32P-labeled O4-(3'-phospho-5'-uridylyl)tyrosine that could be cleaved with micrococcal nuclease to O4-{32P}phosphotyrosine and uridine 3'-{32P}phosphate . These data establish that VPg is linked to the poliovirus genome by a bond between the O4 of tyrosine and the 5'-P atom of the terminal uridylic acid residue . The 5' end of polio genome RNA can now be described as VPg(Tyr-O)-pU-U-A-A-A-A-C-A-G. Mutat Res, 1978 Oct, 52(1), 137 - 49 Molecular mechanisms involved in the production of chromosomal aberrations . I . Utilization of Neurospora endonuclease for the study of aberration production in G2 stage of the cell cycle; Natarajan AT et al.; Chinese hamster ovary cells (CHO) were X-irradiated in G2 stage of the cell cycle and immediately treated, in the presence of inactivated Sendai virus, with Neurospora endonuclease (E.C . 3.1.4.), an enzyme which is specific for cleaving single-stranded DNA . With this treatment, the frequencies of all types of chromosome aberrations increased when compared to X-irradiated controls . These results are interpreted as due to the conversion of some of the X-ray induced single-stranded DNA breaks into double-strand breaks by this enzyme . Similar enhancement due to this enzyme was found following treatment with methyl methanesulfonate (MMS) and bleomycin, but not following UV and mitomycin C . Addition of Micrococcus endonuclease and Neurospora endonuclease to the cells did not alter the frequencies of aberrations induced by UV . The introduction of enzymes with specific DNA-repair function offers possibilities to probe into the molecular events involved in the formation of structural chromosome aberrations induced by different classes of physical and chemical mutagens. Biochim Biophys Acta, 1978 Sep 27, 520(2), 358 - 67 A study of an endogenous nucleolytic reaction and of the action micrococcal nuclease and DNAase I on a salt-soluble, compact form of chromatin; Krueger RC; The endogenous nucleolytic reaction occurring in rabbit thymus nuclear lysates has been studied at extended incubation times (up to 4 h) . Production of nucleosomal polymers containing multiples of 205 base pairs of DNA was observed . The stability of the bands and the low release (1%) of acid-soluble nucleotides indicated there was only a small fraction of sensitive DNA between the subunits . The salt-soluble chromatin formed in the endogenous reaction at short incubation times (14--24 min) and purified over Sephadex G-200 has been treated with micrococcal nuclease and DNAase I . With micrococcal nuclease, nucleosomal polymers containing multiples of 201 base pairs of DNA were formed . Extensive digestion reaveled a core subunit containing 145 base pairs of DNA . With DNAase I only random degradation was observed and nucleosomal complexes were not produced. Chromosoma, 1978 Sep 11, 68(4), 357 - 36 Characterization of restriction nuclease prepared chromatin by electron microscopy; Miller F et al.; Chromatin was solubilized from rat liver nuclei by digestion with the restriction nuclease EcoRI or HaeIII in the presence or absence of EDTA and sodium chloride . The samples were investigated by electron microscopy after positive and negative staining with uranyl acetate under a number of conditions . Depending on the salt concentration during solubilization the chromatin appeared as beads on the string or in more compact form . Solenoid- and superbead-like structures were seen as had been reported for chromatin solubilized with micrococcal nuclease. Rev Esp Fisiol, 1978 Sep, 34(3), 309 - 16 Effect of group specific reagents on the Mg2 +/- dependent activity of purified Micrococcus lysodeikticus ATPase; Carreira J et al.; A series of group specific reagents has been examined for their ability to inactivate Micrococcus lysodeikticus adenosine triphosphatase assayed with Mg2+ as activating divalent cation . The enzyme activity was not inhibited by sulphydryl, carboxyl, histidine, arginine and methionine specific reagents at inhibitor concentrations below 2 mM . However, the ATPase was inactivated by its chemical reaction with either one molecule of trinitrobenzenesulfonic acid or tetranitromethane, or two to four molecules of N-bromosuccinimide . These results suggest that at least one amino group, one tyrosine and two to four tryptophans are involved in the Mg2+-dependent binding or hydrolysis of ATP. Mikrobiologiia, 1978 Sep-Oct, 47(5), 911 - 4 {Comparative study of the action of different antibiotics on the membrane dehydrogenase activity in Micrococcus lysodeikticus}; Kuliash IuV et al.; The object of this work was to study the effect of antibiotics belonging to the groups of penicillin, tetracycline and aminoglycosides on the activity of lactate dehydrogenase, alcohol dehydrogenase and malate dehydrogenase in the membranes of Micrococcus lysodeikticus . Streptomycin, benzylpenicillin, carbenicillin and phenoxymethylpenicillin decreased the activity of the above dehydrogenases . Tetracycline and oxytetracycline activated lactate dehydrogenase and alcohol dehydrogenase in the membranes, but decreased their activity in the supernatant fraction of disintegrated membranes . The enzyme activity in the membranes was particularly inhibited by neomycin. Eur J Biochem, 1978 Sep 1, 89(2), 607 - 18 Purification and characterization of an endonuclease from Micrococcus luteus that acts on depurinated and carcinogen-modified DNA; Hecht R et al.; An endonuclease which is active with regard to depurinated, alkylated, arylated, and arylamidated DNA has been purified 500-fold from Micrococcus luteus . In this purification, separation from the pyrimidine-dimer-specific ultraviolet-endonuclease has been achieved . The enzyme has a molecular weight of 30000 on the basis of gel filtration; its activity is not absolutely dependent upon the presence of Mg2+, but 5--30 mM Mg2+ produces a five-fold stimulation . Potassium chloride concentrations of less than 100 mM are optimal, while concentrations exceeding 100 mM inhibit . The enzyme has no effect on native DNA, but introduces single-strand breaks into DNA containing apurinic/apyrimidinic sites produced by heating at an acidic pH . DNA treated with such carcinogens as N-alkyl-N-nitrosoureas, alkyl methanesulfonates, alkyl sulfates, nitrogen mustard, beta-propiolactone, 7-bromomethyl-benz{a}anthracene, N-acetoxy-2-acetylaminofluorene, and 7,12-dimethyl-benz{a}anthracene-5,6-oxide also becomes susceptible to enzymic action . The activity of the enzyme has been detected by making use of the difference in mobility between supercoiled closed-circular DNA of Pseudomonas phage PM2 and its nicked form in agarose gel elctrophoresis . Even depurinated or carcinogen-modified supercoiled PM2 DNA migrated faster than the respective relaxed nicked forms . A comparison of the number of enzyme-catalyzed single-strand breaks with the number of alkali-labile (i.e . apurinic) sites in carcinogen-modified PM2 DNA showed that the enzyme preparation introduced approximately twice as many breaks into the substrates as the number of apurinic sites present . We conclude that the enzyme preparation either recognizes both apurinic sites and DNA bases carrying carcinogenic residues or contains DNA glycosidase activity in addition to the endonuclease activity . Exposure of ultraviolet-irradiated PM2 DNA to the endonuclease preparation showed that pyrimidine dimers were not substrates . The yield of enzyme-catalyzed single-strand breaks found in ultraviolet-irradiated DNA was five times the number of alkali-labile sites present suggesting that minor photoproducts, possibly 5,6-saturated pyrimidine residues, were recognized in addition to apurinic sites. Eur J Biochem, 1978 Sep 1, 89(2), 567 - 74 The structure of chromatin replicated in vitro; Schlaeger EJ et al.; Nuclei from concanavalin-A-activated lymphocytes were used to study the replication of chromatin in vitro . Micrococcal nuclease was employed to obtain information about the structure of the replicated chromatin . The nuclease digestion products were examined by sucrose gradient sedimentation and by gel electrophoresis . Experiments are presented which indicate that DNA replicated in vitro is organized into chromatin whose structure is similar to that of bulk chromatin . This conclusion is based on the following observations: (a) DNA replicated in vitro is associated with typical chromatin subunits (nucleosomes) even after short replication times, when the newly replicated DNA consists almost entirely of Okazaki fragments; (b) the length of internucleosomal spacer DNA in part of the replicated chromatin corresponds to that in bulk chromatin . Evidence which suggests that the structure of nucleosomes is transiently altered in the vicinity of the replication fork is presented. Biofizika, 1978 Sep-Oct, 23(5), 768 - 74 {Quaternary structure of histidine decarboxylase according to small-angle x-ray diffraction and electron microscopic findings}; Gonchar NA et al.; The data on small angle X-ray scattering with histidine decarboxilase (HDC) from Micrococcus sp . n . were analysed and a line of succesively improving approximations of the molecule shape was found: by oblate ellipsoid a:b:c = 1:10.63, by continuous cylinder and hollow cylinder with H = 50 A, 2R = 76 A, 2r = 8A . Biochemical data and electron micrographs of HDC obtained made possible to distinguish subunits and thus to increase resolution of the model . The model of the enzyme molecule consisting of three subunits is suggested, whose X-ray small angle scattering curve well agrees with the experimental one up to value S = 0.21 A-1. Cell Biol Int Rep, 1978 Sep, 2(5), 495 - 9 Supranucleosomal structure of chromatin; Stratling WH et al.; Rat liver chromatin was moderately digested by micrococcal nuclease and analysed by centrifugation in isokinetic sucrose gradients and electron microscopy . Two classes of particles sedimenting with about 33S and 60S were characterized . Kinetics of their appearance and disappearance during progressive digestion suggests that they represent monomers and dimers cleaved from a higher order (supranucleosomal) structure of chromatin . Biochemical and electron microscopical results suggest that the monomers and dimers contain eight and sixteen nucleosomes, respectively, which are densely packed into 23 nm (monomer) and 29 nm (dimer) globules. Antibiotiki, 1978 Sep, 23(9), 797 - 802 {Action of egg lysozyme on representatives of the family Micrococcaceae . Its action on Micrococcus}; Safonova TB et al.; The results of the study of the effect of various concentrations of egg lysozyme on M . luteus and M . varians using 2 methods, i.e . serial dilutions in agar and turbidimetric are presented . It was found that the MIC of lysozyme for M . luteus ranged within wide limits, from less than 0.0003 to 1 mg/ml . M . varians was stable to lysozyme . The MIC for all the strains was 8 mg/ml . The turbidimetric method provided determination of general regularities in changes of the optical density in all the strains of M . luteus under the effect of various concentrations of lysozyme . On the basis of these data it was possible to consider the method as the most deep means for determining the intraspecies similarities in the surface structures of Micrococcus as compared to the method of serial dilutions in agar . The dynamics of the changes in the optical density of the M . luteus suspension markedly differed from that of M . varians. J Clin Microbiol, 1978 Sep, 8(3), 306 - 12 Neutralization of human serum lysozyme by sodium polyanethol sulfonate but not by sodium amylosulfate; Traub WH et al.; Sodium polyanethol sulfonate (SPS) at 500 microgram/ml, but not sodium amylosulfate (SAS) at 500 microgram/ml, precipitated egg white lysozyme (1 mg and 50 microgram of lysozyme per ml) as determined with the assay strain Micrococcus lysodeikticus ATCC 4698 . Fresh and heat-inactivated (56 degrees C, 30 min) human serum (80%, vol/vol) killed M . lysodeikticus (10(4) bacteria per ml at zero time) within 1 to 2 h after exposure . Addition of 250 to 500 microgram of SPS per ml to fresh human serum protected M . lysodeikticus for 22 h as effectively as absorption of either fresh or heat-inactivated human serum with bentonite (10 mg/ml of serum, 10 min, 37 degrees C); the latter procedure is known to remove serum lysozyme . In contrast, SAS at 250 and 500 microgram/ml of serum retarded killing of the assay bacteria for periods of 4 h; after overnight (22 h) incubation, however, the number of M . lysodeikticus survivors had decreased significantly . The finding that SPS, but not SAS, at 250 to 500 microgram/ml effectively neutralized serum lysozyme-mediated killing of a lysozyme-sensitive assay strain may be of relevance with respect to laboratory processing of human blood culture specimens. Vet Med (Praha), 1978 Sep, 23(9), 549 - 54 {Examination of market carps for residues of antimicrobial agents}; Malikova M et al.; The residues of inhibitory substances in the muscle, hepatopancreas, bile, and pyloric caeca of 30 carps from ponds south of Brno were examined by the microbiological diffusion method . The following testing micro-organisms were used: B . cereus var . mycoides (ATCC 11778), B . subtilis (ATCC 6633), Sarcina lutea (ATCC 9341), and Micrococcus flavus (ATCC 10240) . Residues of inhibitory substances were not found in any of the muscle samples tested . The rest of the tested tissues showed, in some cases, small inhibition zones which seem to be due to the presence of natural antimicrobially active substances in the bile and gastro-intestinal tract of the fish rather than to the persistence of the residues of drugs given to the fish during their life. Biochim Biophys Acta, 1978 Aug 23, 520(1), 122 - 30 An exonuclease activity associated with DNA polymerase I of Micrococcus radiodurans; Kitayama S et al.; An exonuclease activity is associated with one of three DNA polymerase in Micrococcus radiodurans . The nuclease activity co-sedimented with its DNA polymerase I of this bacterium on glycerol gradient centrifugation . Both activities show the same optimum pH and heat-inactivation kinetics . This nuclease hydrolyzes preferentially double-stranded DNA in an exonucleolytic manner from both ends of the duplex DNA . The products of hydrolysis are mostly deoxyribonucleoside 5'-monophosphate and no nucleosides are released into the acid-soluble fraction . Di- or other oligonucleotides are also produced but their relative amounts are constant during the time of incubation . The exonuclease activity requires Mg2+ and is inhibited by high concentrations of KCl as is DNA polymerase I of M . radiodurans. Biochem J, 1978 Aug 15, 174(2), 475 - 83 Chromatin structure through the cell cycle . Studies with regeneration rat liver; Caplan A et al.; Liver nuclei were prepared through the first cell cycle in partially hepatectomized young rats showing 30% parenchymal cell synchrony . To determine if nucleosome structure altered during this period, liver nuclei from sham-operated rats were compared with nuclei isolated at various times after partial hepatectomy . These nuclei were exposed to deoxyribonuclease I (EC 3.1.4.5), deoxyribonuclease II (EC 3.1.4.6) or micrococcal nuclease (EC 3.1.4.7) and the nucleosome-associated DNA length was ascertained . In no case was a difference in the DNA lengths associated with nucleosome structure observed . Differences were observed with regard to the histones and their relative association with nuclear material . When nuclei from normal rat livers were incubated in hypo-osmolar medium 9% of histone 1 and 4% of the other histones were released . These released histones, unlike those remaining bound to the nuclei, showed high {3H}adenosine and {3H}acetate uptakes in vivo . {32P}P1 uptake was also much greater into released than bound histones 1 and 3, but was not different for histone2A . At 3.5-4.5 h after partial hepatectomy, the release of histone 1 was trebled and that of histone 4 doubled . By 13.5 h, when phosphorylation of the bound forms of histones 2A and especially 1 was increased, no further changes in histone release in hypo-osmolar medium were found . The released histones from partially hepatectomized livers had indistinguishable {3H}adenosine uptakes from controls . The roles are discussed of phosphorylation and ADP-ribosylation in labilizing histone binding. J Biochem (Tokyo), 1978 Aug, 84(2), 337 - 42 Cellular factors for stimulation of nucleosomal template activity for in vitro DNA synthesis; Akiyoshi H et al.; Nucleosomes isolated from Yoshida sarcoma chromatin by micrococcal nuclease treatment were relatively inactive as templates for in vitro DNA synthesis . However, the template activity increased by trypsin digestion of nucleosomes or addition of heparin to the reaction mixture . This indicates that the nucleosomal template activity is masked . A crude extract of Yoshida sarcoma cells stimulated the nucleosomal template activity . The stimulatory factor was separated into three peaks by DEAE cellulose column chromatography . The same three peaks were observed in normal rat liver extract with much lower activities, but enhanced in regenerating liver . The factors seem to stimulate DNA synthesis by activating DNA template in nucleosomes without degrading histones or changing the primary structure of nucleosomal DNA. Nucleic Acids Res, 1978 Aug, 5(8), 2999 - 3012 Transcription of nucleosomes from human chromatin; Shaw PA et al.; Nucleosomes (chromatin subunits) prepared by micrococcal nuclease digestion of human nuclei are similar in histone content but substantially reduced in non-histone proteins as compared to undigested chromatin . Chromatin transcription experiments indicate that the DNA in the nucleosomes is accessible to DNA-dependent RNA polymerase in vitro . The template capacities of chromatin and nucleosomes are 1.5 and 10%, respectively, relative to high molecular weight DNA, with intermediate values for oligonucleosomes . Three distinct sizes of transcripts, 150, 120 and 95 nucleotides in length, are obtained when nucleosomes are used as templates . However, when nucleosomal DNA is used as a template, the predominant size of transcripts is 150 nucleotides . When oligonucleosomes are used as templates longer transcripts are obtained . This indicates that RNA polymerase can transcribe the DNA contained in the nucleosomes. Proc Natl Acad Sci U S A, 1978 Aug, 75(8), 3717 - 21 Ribonuclease P: an enzyme with an essential RNA component; Stark BC et al.; The activity of ribonuclease P on precursor tRNA substrates from Escherichia coli can be abolished by pretreatment of this enzyme with micrococcal nuclease or pancreatic ribonuclease A, as well as by proteases and by thermal denaturation . Highly purified RNase P exhibits one prominent RNA and one prominent polypeptide component when examined in polyacrylamide gels containing sodium dodecyl sulfate . The buoyant density in CsCl of RNase P, 1.71 g/ml, is characteristic of a protein-RNA complex . The activity of RNase P is inhibited by various RNA molecules . The presence of a discrete RNA component in RNase P appears to be essential for enzymatic function . A model is described for enzyme-substrate recognition in which this RNA component plays an important role. Proc Natl Acad Sci U S A, 1978 Aug, 75(8), 3583 - 7 Compact oligomers and nucleosome phasing; Tatchell K et al.; Micrococcal nuclease (EC 3.1.4.7) digestion of histone H1- and H5-depleted chicken erythrocyte chromatin yields, in addition to 140-base-pair (bp) core particles, a series of nucleosome oligomers containing about 260 bp (compact dimer), 380 bp (compact trimer), etc . of DNA . These are postulated to represent members of a class of oligomers in which the DNA is tightly wound on stacked protein cores . The physical properties (melting, circular dichroism) as well as DNase I (EC 3.1.4.5) digestion patterns support this view . DNase I digestion of tight oligomers in which the 5' ends of the DNA have been labeled yields results consistent with this model and inconsistent with some other possible models . Several classes of such particles are postulated to exist, differing in DNA length by 10-bp increments . This may be an explanation of the 10-bp nucleosome "phasing" that has been observed in some nuclei. J Protozool, 1978 Aug, 25(3 Pt 2), 385 - 7 Particle-based axenic media for tetrahymenids; Keenan K et al.; Autoclavable, natural particulate media simplify axenic cultivation of tetrahymenid ciliates and presumably favor selection for phagotrophy . Viability is at least 2 months at room temperature (24-26 C) for the lipid-sensitive tetrahymenids Tetrahymena setosa, T . corlissi, T . paravorax, T . limacis, and T . patula, also for T . rostrata and (at 12 C), for strains of the T . pyriformis complex and Glaucoma chattoni . A typical medium consists of crude soy "lecithin" + skim milk powder + Saccharomyces cerevisiae cells . Other useful particules readily available commercially are: whole liver powder, cells of Micrococcus lysodeikticus and Escherichia coli, and powdered residue of liver which had been extracted with 70% ethanol ("liver No . 2) . Preliminary experiments indicate that some of these media are suitable for the maintenance of Paramecium octaurelia stock 299S and Colpidium campylum . Such mixtures may serve as points of departure for devising media for more fastidious phagotrophs. Biochim Biophys Acta, 1978 Jul 25, 530(1), 1 - 8 Formation of spirodilactone of 4-(2'-carboxyphenyl)-4,4-dihydroxybutyrate from 2-succinylbenzoate in cell-free extracts of Micrococcus luteus; Hutson KG et al.; The enzyme mediated ATP- and, to a lesser extent, CoASH-dependent synthesis of the spirodilactone of 4-(2'-carboxyphenyl)-4,4-dihydroxybutyrate from 2-succinylbenzoate has been demonstrated in membrane-free extracts of Micrococcus luteus and Escherichia coli . The suggestion is made that the spirodilactone is the product of an aberrant reaction involving a compound that is normally an intermediate in the conversion of 2-succinylbenzoate to 1,4-dihydroxy-2-naphthoate. Eur J Biochem, 1978 Jul 17, 88(1), 253 - 7 8-Azido-adenosine 5'-triphosphate as a photoaffinity label for bacterial F1 ATPase; Scheurich P et al.; 1 . 8-Azido-adenosine 5'-triphosphate (n83ATP) is a suitable photoaffinity label for F1 ATPase from Micrococcus luteus . The nucleotide is a substrate in the presence of bivalent cations and inhibits the enzyme irreversibly upon irradiation with ultraviolet light above 300 nm . 2 . More than 80% of the label is covalently bound to the beta subunits in the presence of bivalent cations . Labeling and inactivation is decreased by protection with ADP, ATP or adenyl-5'-yl imidodiphosphate . To a much smaller degree the alpha subunits also become labeled . 3 . n83AMP does not specifically bind to the beta subunits upon irradiation . Like n83ATP and n83ADP, it also labels the alpha subunits to a small extent . 4 . The F1 ATPase is inactivated after a single beta subunit per F1 complex has become labeled . A cooperativity of the beta subunits carrying nucleotide binding sites is suggested. Biochemistry, 1978 Jul 11, 17(14), 2934 - 8 Organization of 5-methylcytosine in chromosomal DNA; Solage A et al.; The 5-methylcytosine residues of L-cells have been labeled with {methyl-3H}-L-methionine and their chromatin localization studied using deoxyribonucleases . The kinetics of micrococcal nuclease digestion showed that the methylated cytosine residues are concentrated within regions resistant to nuclease digestion and preferentially missing from those regions between nucleosomes which are nuclease sensitive . Using DNA hybridization kinetic analysis, it is shown that 5-methylcytosine is abundant in highly repeated sequences but is also present in middle repetitive and unique sequence DNA. Mikrobiologiia, 1978 Jul-Aug, 47(4), 629 - 36 {Growth of Micrococcus lysodeikticus bacteria on a deuterated medium}; Eremin VA et al.; The object of this work was to prepare deuterated growth media and to adapt Micrococcus lysodeikticus to a medium containing deuterated-substituted organic substances and deuterium oxide instead of water . M . lysodeikticus was grown on a medium prepared from the "deuterated-cells" of Chlorella, and was capable of absorbing selectively protons from such a medium containing high concentrations of deuterium . Its deuterated cells ("monsters") produced structures consisting of several (up to 8) smaller cells, angular in shape and having a thicker (2--3 times) cell wall . Apparently, adaptation to a deuterated medium is accompanied with changes in the cell wall biosynthesis as a result of which the separation of daughter cells is interfered with in the course of cell division, and the cells are more resistant to the action of lysozyme. Zentralbl Bakteriol {Orig A}, 1978 Jul, 241(1), 30 - 5 Serological investigations on the polylysogeny of micrococci; Peters G et al.; Specific antisera against 11 micrococcal phages could be produced by immunization of rabbits . Using the neutralisation test all antisera were tested against their homologous and heterologous phages . The corresponding K-values were calculated . It could be demonstrated that phages coming from the same micrococcal donor strain can be of different genetical relationship . Therefore it was concluded that micrococci can be not only lysogenic but also polylysogenic. Biochem J, 1978 Jul 1, 173(1), 115 - 28 Bifunctional intercalation and sequence specificity in the binding of quinomycin and triostin antibiotics to deoxyribonucleic acid; Lee JS et al.; Quinomycin C, triostin A and triostin C are peptide antibiotics of the quinoxaline family, of which echinomycin (quinomycin A) is also a member . They all remove and reverse the supercoiling of closed circular duplex DNA from bacteriophage PM2 in the fashion characteristic of intercalating drugs, and the unwinding angle at I 0.01 is, in all cases, almost twice that of ethidium . Thus, as with echinomycin, they can be characterized as bifunctional intercalating agents . For the triostins this conclusion has been confirmed by measurements of changes in the viscosity of sonicated rod-like DNA fragments; the helix extension was found to be almost double that expected for a simple monofunctional intercalation process . For triostin A, further evidence for bifunctionality was derived from the cross-over point of binding isotherms to nicked circular and closed circular bacteriophage-PM2DNA . Binding curves for the interaction of quinomycin C and triostin A with a variety of synthetic and naturally occurring nucleic acids were determined by solvent-partition analysis, but triostin C was too insoluble in aqueous solution to make this method applicable . For quinomycin C the highest binding constant was found with Micrococcus lysodeikticus DNA, and its pattern of specificity among natural DNA species was broadly similar to that of echinomycin, although the binding constants were 2--6 times as large . For triostin A the highest binding constant was again found for M . lysodeikticus DNA, but the specificity pattern was quite different from that of the quinomycins . In particular, triostin A bound better to poly(dA-dT) than to the poly(dG-dC) whereas this order was reversed for quinomycin C . There was also evidence that the binding to poly(dA-dT) might be co-operative in nature . No significant interaction could be detected with poly(dA).poly(dT) or with RNA from Escherichia coli . Poly(dG).poly(dC) gave variable results, depending on the source of the polymer . The different patterns of specificity displayed by the quinomycins and triostins are tentatively ascribed to differences in their conformations in solution. Hoppe Seylers Z Physiol Chem, 1978 Jul, 359(7), 857 - 62 Subunit structure of Micrococcus luteus catalase . Dissociation of M . luteus catalase induced by dodecylsulfate, citraconic and 2,3-dimethylmaleic anhydrides and urea; Marie AL et al.; M . luteus catalase dissociates upon treatment with urea, dodecylsulfate and anhydrides into monomers, the molecular weight of which appears to be 1/4 of that of the native enzyme . The urea-induced dissociation depends upon the incubation time, the urea concentration and the pH of the incubation mixture . Reassociation of the subunits proved to be unsuccessful . Native M . luteus catalase only contains 30% alpha-helix . When fully dissociated in presence of urea, it still retains 15% alpha-helix . Catalase from M . luteus was found to lack cysteine residues. Mutat Res, 1978 Jul, 51(1), 121 - 32 Increased sensitivity of UV-repair-deficient human cells to DNA bound platinum products which unlike thymine dimers are not recognized by an endonuclease extracted from Micrococcus luteus; Fraval HN et al.; We have studied the response of human cells in culture to cis platinum{II} diammine dichloride (cis Pt{II}) induced DNA damage . The survival data, measured as a function of cis Pt{II} dose were similar in a normal cell line (Human foetal lung) compared to a UV-sensitive, thymine dimer excision repair-deficient cell line (Xeroderma pigmentosum) . However, there was a marked difference between the two cell lines when binding to DNA was plotted against dose of cis Pt{II} given for 1 h . When these findings were expressed as cell survival versus binding to DNA, a 4.1--fold difference between the slopes of the survival curves for the two cell lines was obtained . These findings are consistent with the notion that normal cells are able to excise cis Pt{II} induced damage from their genome and thus increase their ability to survive as compared to excision-deficient cells . An endonuclease preparation from Micrococcus luteus is able to recognise UV damage in DNA, but did not recognise cis Pt{II} induced damage . These results possibly indicate differences in the pathways of repair of damage caused by the two agents. J Virol, 1978 Jul, 27(1), 127 - 35 Photochemical addition of the cross-linking reagent 4,5', 8-trimethylpsoralen (trioxaslen) to intracellular and viral simian virus 40 DNA-histone complexes; Hallick LM et al.; We demonstrated here that 4,5', 8-trimethylpsoralen (trioxsalen) is a valuable probe for the structure of SV40 DNA-histone complexes . Trioxsalen readily penetrated intact cells and, in the presence of 340- to 380-nm light, covalently cross-linked DNA preferentially at the sites available for micrococcal nuclease digestion . Histograms of the lengths of the regions of SV40 DNA protected from cross-linking, as visualized by electron microscopy, indicated a repeating pattern of base pairs in DNA from both infected cells and virus particles . The ability of the trioxsalen probe to act in vivo and to map the location of protected regions may provide a powerful tool for analyzing the role of nucleosomes in the structure of the virus particle and in intracellular complexes such as transcription templates and replication intermediates. J Biol Chem, 1978 Jun 25, 253(12), 4292 - 6 Kinetic studies on bacterial plasma membrane ATPase (F1) . Nucleotide-induced long term inactivation of ATP hydrolyzing activity is linked to the formation of multiple "tight" enzyme nucleotide complexes; Hockel M et al.; ADP and the ATP analogs Nb-S6ITP (6-{(3-carboxy-4-nitrophenyl)thio}-9-beta-D-ribofuranosylpurine 5'-triphosphate) and AMP-P(NH)P (adenyl-5'-yl imidodiphosphate) interact with soluble plasma membrane ATPase (F1) from Micrococcus species in two ways: (i) at short incubation times, these inhibitors exhibit the kinetics of competitive inhibition, (ii) at long incubation times, these inhibitors induce an inactivation of the ATPase which can be reversed only in the case of AMP-P(NH)P . Kinetic treatment of the long term inactivation by ADP or Nb-S6ITP reveals a pseudo-first order process via the formation of an enzyme-inhibitor complex for which a Km analogous constant is obtained that is identical with the corresponding Ki value of the competitive inhibition . The long term inactivation by ADP and Nb-S6ITP involves the successive "tight" binding of 6 +/- 1 nucleotides/F1 molecule . One additional ADP molecule/F1 complex which is also "tightly" bound has no effect on the ATPase activity . The long term inactivation by ADP and Nb-S6ITP is inhibited at higher inhibitor concentrations according to a kinetics analogous to a substrate excess inhibition . Evidence is presented indicating that the mechanism of ATP hydrolysis by F1 and the long term inactivation by ADP or Nb-S6ITP are related processes . The mechanism of long term inactivation by AMP-P(NH)P appears to be different from that of ADP or Nb-S6ITP. Biochim Biophys Acta, 1978 Jun 9, 524(2), 362 - 72 The radiation-releasable cell wall nuclease of Micrococcus radiodurans . Purification and properties of the native enzyme; Mitchel RE; Micrococcus radiodurans is known to possess a surface nuclease located in a mid-wall layer . Previous work showed that hydroxyl radicals, generated by sublethal doses of ionizing radiation, attack the cell wall and initiate release of the active enzyme into the external medium . The enzyme from unirradiated cells has now been purified to homogeneity by a simple 3-step process . The nuclease is a dimer of molecular weight about 260 000 and exonucleolytically degrades both DNA and RNA to 5'-mononucleotides . Single-stranded DNA is degraded at a rate about 200 times faster than double-stranded DNA . Oligonucleotides bearing a terminal 3'-phosphate are resistant to digestion . Dinucleotides must possess a 5'-terminal phosphate and a free 3'-terminal OH to be hydrolyzed . The enzyme has a pH optimum of about 9.0 . A metal ion, possibly Ca2+, appears to be tightly bound to the protein . Removal of this metal with EDTA inactivates the enzyme . Simple readdition of Ca2+ does not restore activity although partial function can be recovered by renaturation from urea in the presence of this ion . The availability of pure enzyme should aid in the detection of radiation induced alterations which may be involved in the mechanism of its release from the cell wall. Biochim Biophys Acta, 1978 Jun 2, 509(3), 410 - 8 Immunological properties of membrane-bound adenosine triphosphatase: immunological identification of rutamycin-sensitive F0.F1ATPase from Micrococcus luteus ATCC 4698 established by crossed immunoelectrophoresis; Schmitt M et al.; (1) F0.F1ATPase (EC 3.6.1.3) from Micrococcus luteus ATCC 4698 was solubilized from plasma membranes by the non-ionic detergent Triton X-100 in the presence of 0.05 M MgCl2 . (2) The antibiotics rutamycin, Dio-9, quercetin, oligomycin, botrycidin, efrapeptin, leucinostatin, valinomycin, and venturicidin as well as N,N'-dicyclohexylcarbodiimide and dinitrophenol are potent inhibitors of F0.F1ATPase activity.(3) F0.F1ATPase activity is completely inhibited by anti-F1ATPase antibodies . The inhibition is non-competitive . (4) Crossed immunoelectrophoresis reveals a reaction of immunological identity of F0.F1ATPase and F1ATPase indicating that both enzymes have in common antigenic sites. Cytobiologie, 1978 Jun, 17(1), 1 - 9 The structure of a periodic cell wall component (HPI-layer of Micrococcus radiodurans); Kubler O et al.; The hexagonally packed interlayer (HPI-layer) from Micrococcus radiodurans cell walls has been studied by electron microscopy and subsequent digital image processing . The most prominent feature in the average images is a "complex" shaped like a "toothed wheel", which is perforated by a central pore and interconnected by fine spokes . This basic structural element is tentatively interpreted to represent the bulk of HPI-layer protein, intercalated by the other constituents: lipids, carotenoids and carbohydrates . It is suggested that the "toothed wheel" structure is a quite common element of periodic bacterial surface layers and that the different spacings observed with various species are due to variable amounts of intercalating material. J Virol, 1978 Jun, 26(3), 817 - 21 Peptide mapping characterization of viral proteins generated in a cell-free coupled system for the transcription and translation of influenza virus mRNA; Content J et al.; In a coupled cell-free system for the transcription and translation of the influenza mRNA's, containing detergent-disrupted purified NWS influenza virion and a micrococcal nuclease-preincubated rabbit reticulocyte lysate, five unglycosylated viral proteins (NS1, M, NP, P1, and P3) were easily produced and isolated . Their identification was based on the electrophoretic separation of peptide fragments resulting from their partial digestion with proteases of restricted specificity (D.W . Cleveland, S . G . Fisher, N . W . Kirschner, and U . K . Laemmli, J . Biol . Chem . 252:1102-1106, 1977). J Clin Microbiol, 1978 Jun, 7(6), 546 - 9 Endocarditis associated with cardiac catheterization due to a Gram-positive coccus designated Micrococcus mucilaginosus incertae sedis; Rubin SJ et al.; A gram-positive coccus, presently named Micrococcus mucilaginosus incertae sedis, was isolated from 14 blood cultures from a patient with endocarditis . The first positive blood culture was drawn 5 days after the patient underwent cardiac catheterization. Can J Biochem, 1978 Jun, 56(6), 480 - 91 A study of the localization of high mobility group proteins in chromatin; Levy WB et al.; High mobility group (HMG) proteins from fetal calf thymus and mouse brain chromatin were purified and compared electrophoretically . The four major HMG proteins characteristic of fetal calf thymus chromatin (HMG's 1, 2, 14, and 17) were also found to be present in mouse brain chromatin . Nuclei from these two eucaryotic tissues were digested with DNase I and micrococcal nuclease and the acid-soluble proteins solubilized by the two nucleases in both tissues were analyzed on starch gels . Limited digestion of fetal calf thymus nuclei with DNase I led to the solubilization of a substantial fraction of proteins HMG-1 and HMG-2 together with smaller amounts of H1 . In addition, limited digestion with micrococcal nuclease released approximately 70% of HMG's 1 and 2 and variable amount of H1 into the soluble fraction . The observation that HMG proteins 1 and 2 are selectively solubilized under conditions in which active genes have been shown to be preferentially digested in various other cell types suggests their selective association with chromatin regions which are transcriptionally competent. Nucleic Acids Res, 1978 May, 5(5), 1675 - 87 Nucleosome-associated proteins and phosphoproteins of differentiating Friend erythroleukemia cells; Neumann J et al.; Mononucleosomes derived from brief digestion of uninduced Friend cell nuclei with micrococcal nuclease contain a set of non-histone chromosomal proteins which are partly or altogether missing in the oligomeric nucleosomes . On the other hand, the latter contain a protein of Mr 190,000 not seen in the mononucleosomes . Longer digestion removes most of these non-histone proteins, excepting the Mr 190,000 protein . Brief digestion of nuclei from Friend cells induced by DMSO or by n-butyrate removes most of the non-histone proteins from the nucleosomes, as did the prolonged digestion of uninduced nuclei . The Mr 190,000 protein remains, while a protein of Mr 27,000 is increased . The rate of phosphorylation of histone H1 associated with mononucleosomes was 3 to 4-fold greater in cells induced with DMSO . The major phosphoprotein and most of the other phosphorylated non-histones were modified at the same rate in control and induced cells . However, a Mr 95,000 protein was less phosphorylated in the induced cells. Proc Natl Acad Sci U S A, 1978 May, 75(5), 2130 - 4 Assembly of new nucleosomal histones and new DNA into chromatin; Hancock R; The assembly of chromatin from newly synthesized nucleosomal histones (labeled with {3H}arginine) and new DNA (density-labeled with {125I}iododeoxyuridine)was studied in growing cultured mouse cells . The nucleosomal histones were specifically examined by dissociating histone H1 and nonhistone proteins from unsheared chromatin either by incubation in 0.6 M NaCl or by digestion with micrococcal nuclease to release nucleosomes . In both cases, the four nucleosomal histones (H2A, H2B, H3, and H4) are essentially the only proteins that remain bound to DNA and that are labeled by {3H}arginine . After formaldehyde fixation, H1-depleted chromatin containing dense DNA can be completely resolved in CsCl buoyant density gradients from that containing unreplicated DNA; separation of nucleosomes is satisfactory although less complete . New DNA and new histones are already assembled into chromatin possessing characteristic nucleosomal structure after 3 min of synthesis (the shortest time studied), as shown by the kinetics of digestion of new DNA by micrococcal nuclease, by the distribution of new DNA and new histones in nucleosomes . However, after 3-30 min of synthesis most new nucleosomal histones are associated with unreplicated DNA rather than with new DNA . It is concluded that new nucleosomes are assembled on DNA at some distance from DNA replication sites, with concomitant migration of preexisting nucleosomes onto new DNA. Proc Natl Acad Sci U S A, 1978 May, 75(5), 2098 - 102 Micrococcus luteus DNA gyrase: active components and a model for its supercoiling of DNA; Liu LF et al.; Two active components alpha and beta of micrococcus luteus DNA gyrase, of peptide weights of 115,000 and 97,000, respectively, have been purified . Each individual component exhibits little DNA gyrase activity; the ATP-dependent negative supercoiling of a covalently closed circular DNA duplex is catalyzed by a combination of the two . Covalent closure by Escherichia coli ligase of a circular DNA containing single-chain scissions, when carried out in the presence of a combination of the DNA gyrase components alpha and beta, gives a positively supercoiled DNA upon removal of the bound protein molecules . ATP was not present during the ligase treatment; therefore the positive supercoiling of DNA observed is a result of the binding of gyrase molecules, presumably as multi-subunit oligomers, during the ligation step . This is in contrast to the negative supercoiling of DNA catalyzed by gyrase in the presence of ATP . A model in which negative supercoiling of DNA is achieved by ATP-modulated repetitive wrapping of the DNA around gyrase is described . The model also suggests a plausible mode of action by which translocation of a DNA along its helix axis can be actively driven by an ATPase. Chromosoma, 1978 Apr 25, 66(3), 259 - 68 Selective digestion of mouse metaphase chromosomes; Rattner JB et al.; Metaphase chromosomes prepared from colcemid-treated mouse L929 cells by non-ionic detergent lysis exhibit distinct heterochromatic centromere regions and associated kinetochores when viewed by whole mount electron microscopy . Deoxyribonuclease I treatment of these chromosomes results in the preferential digestion of the chromosomal arms leaving the centromeric heterochromatin and kinetochores apparently intact . Enrichment in centromere material after DNase I digestion was quantitated by examining the increase in 10,000 X g pellets of the 1.691 g/cc satellite DNA relative to main band DNA . This satellite species has been localized at the centromeres of mouse chromosomes by in situ hybridization . From our analysis it was determined that DNase I digestion results in a five to six-fold increase in centromeric material . In contrast to the effect of DNase I, micrococcal nuclease was found to be less selective in its action . Digestion with this enzyme solubilized both chromosome arms and centromeres leaving only a small amount of chromatin and intact kinetochores. Mol Cell Biochem, 1978 Apr 11, 19(2), 93 - 112 Periodicity and fragment size of DNA from mouse TLT hepatoma chromatin and chromatin fractions using endogenous and exogenous nucleases; Duerksen JD et al.; The action of micrococcal nuclease, DNase I and DNase II on mouse TLT hepatoma chromatin revealing the periodicity of its structure as visualized by denaturing and non-denaturing gel electrophoresis, was consistent with the action of these enzymes on other chromatins . Micrococcal nuclease showed a complex subnucleosome fragment pattern based on multiples of 10 base pairs with a prominant couplet at 140/160 base pairs and the absence of the 80 base pair fragment . This couplet of the core and minimal nucleosome fragments was conspicuously present in the mononucleosomes found in the 11S fractions of a glycerol gradient centrifugation . DNase I and II produced a fairly even distribution of a 10 base pair increasing series of fragments to about 180 base pairs, a pattern also repeated in the DNA of nucleosome glycerol-gradient fractions . In limited digestions by these nucleases multinucleosomic DNA fragments are pronounced . These fragment lengths are multiples of an estimated average repeat length of nucleosome DNA of 180 base pairs . The action of the endogenous Mg/Ca-stimulated endonuclease produced only limited cuts in the hepatoma chromatin resulting primarily in multi-nucleosomic DNA fragment lengths and only upon lengthy digestion limited subnucleosomic, 10-base-pair multiple fragments are produced . The putative euchromatin-enriched fractions (50-75S) of the glycerol gradient centrifugation of autodigested chromatin, similarly, contained primarily the multinucleosomic DNA fragment lengths . These results are consistent with our previous electron microscopic demonstration that autodigested chromatin as well as the putative euchromatin-enriched fractions were composed of multi-nucleosomic chromatin segments containing a full complement of histones. Nucleic Acids Res, 1978 Apr, 5(4), 1413 - 28 Enzymes from Micrococcus luteus involved in the initial steps of excision repair of spontaneous DNA lesions: uracil-DNA-glycosidase and apurinic-endonucleases; Tomlin NV et al.; Uracil-DNA-glycosidase that releases free uracil from single-stranded or double-stranded deaminated DNA and poly d(A-U) has been partially purified from Micrococcus luteus . The enzyme has a molecular weight of about 16,000 and can be separated from uracil-endonuclease and endonucleases (AP-endonucleases) specific for apurinic and apyrimidinic sites . Uracil-DNA-glycosidase does not act on guanine residues opposite uracil in double-stranded DNA and on xanthine in deaminated DNA . The glycosidase generates apyrimidinic sites which can serve as substrate sites for different AP-endonucleases from M . luteus. J Bacteriol, 1978 Apr, 134(1), 71 - 5 Multiplicity of genome equivalents in the radiation-resistant bacterium Micrococcus radiodurans; Hansen MT; The complexity of the genome of Micrococcus radiodurans was determined to be (2.0 +/- 0.3) X 10(9) daltons by DNA renaturation kinetics . The number of genome equivalents of DNA per cell was calculated from the complexity and the content of DNA . A lower limit of four genome equivalents per cell was approached with decreasing growth rate . Thus, no haploid stage appeared to be realized in this organism . The replication time was estimated from the kinetics and amount of residual DNA synthesis after inhibiting initiation of new rounds of replication . From this, the redundancy of terminal genetic markers was calculated to vary with growth rate from four to approximately eight copies per cell . All genetic material, including the least abundant, is thus multiply represented in each cell . The potential significance of the maintenance in each cell of multiple gene copies is discussed in relation to the extreme radiation resistance of M . radiodurans. Mutat Res, 1978 Apr, 50(1), 43 - 56 Removal of pyrimidine dimers from Saccharomyces cerevisiae nuclear DNA under nongrowth conditions as detected by a sensitive, enzymatic assay; Reynolds RJ; A sensitive and quantitative procedure for the detection of pyrimidine dimers in yesast nuclear DNA is described . The assay employs dimer-specific, endonuclease activities from Micrococcus luteus together with DNA sedimentation through calibrated, alkaline sucrose gradients to detect endonuclease-induced, single-strand breaks . Breaks were induced in a dose-dependent manner from 0 to 80 J m-2 at 254 nm and in numbers equivalent to the numbers of dimers induced by similar doses (Unrau et al., Biochim . Biophys . Acta, 312 (1973) 626--632) . This procedure also allows the use of {6-3H} uridine to label cellular nucleic acids, but dose not require extensive DNA purification to eliminate concomitantly labeled RNA . Endonuclease-sensitive sites in the wild-type, haploid strain S288C, after irradiation with 5 J m-2 (254 nm), were removed in less than 5 min when cells were incubated in buffer (pH 7.0) at 28 degrees C . After irradiation with doses from 30 to 100 Jm-2 site removal in S288C required longer postirradiation incubations and was about 90% complete . In a radiation-sensitive strain carrying the mutant allele rad4-3 the number of endonuclease-sensitive sites remained constant for 6 h after irradiation with 5 Jm-2 . The retention of sites in this strain indicates that it is defective in the excision of pyrimidine dimers. Nucleic Acids Res, 1978 Mar, 5(3), 723 - 38 Estrogen receptor in hen oviduct chromatin, digested by micrococcal nuclease; Massol N et al.; Nuclei from laying hen oviduct were prepared according to Hewish and Burgoyne i.e . in the presence of spermine and spermidine and in the absence of divalent cations and were then moderately digested by micrococcal nuclease . When the resulting chromatin was analysed by ultracentrifugation on a sucrose gradient, a peak of specific estradiol-binding sites was observed, sedimenting slightly faster (13-14 S) than the mononucleosomes (12 S) . When the chromatin was centrifuged on a gradient containing heparin (5 microngram/ml) the sedimentation coefficient of the estradiol receptor peak shifted to 7-8 S; it returned to the 13-14 S position in the absence of heparin, when target organ chromatin was also present in the gradient . The preparation of the chromatin is described and the validity of the method to explore receptor localisation is discussed, as is the specificity of the receptor-DNA interaction. J Biochem (Tokyo), 1978 Mar, 83(3), 639 - 46 Fractionation of unfixed chromatin by buoyant-density centrifugation in gradients containing 3-iodo-1,2-propanediol and metrizamide; Senshu T et al.; Buoyant-density centrifugation of unfixed chromatin has been performed in a newly devised medium containing 3-iodo-1,2-propanediol and metrizamide . Chromatins were obtained from isotopically labeled mouse hepatoma cells in suspension culture, either grown normally or density labeled in a medium containing bromodeoxyuridine, by mild digestion of isolated nuclei with micrococcal nuclease . When a mixture of normal and density labeled chromatin, marked with {14C}thymidine and {3H}bromodeoxyuridine, respectively, was centrifuged in the medium, chromatin peaks represented by labeled DNA were resolved to the extent expected from their separate banding profiles . Centrifugation of an equivalent chromatin mixture labeled with {14C} and {3H}lysine, respectively, also yielded resolution of chromatin peaks represented by labeled proteins . Only small amounts of labeled proteins were dissociated from chromatin in the gradient medium . Labeled proteins recovered from the gradient fractions were analyzed by electrophoresis on sodium dodecyl sulfate-polyacrylamide gels . The results suggested that most of the histones remained associated with the original stretches of DNA during the centrifual fractionation period . Essentially all of the dissociated proteins were found to be non-histone proteins. Eur J Biochem, 1978 Mar, 84(1), 95 - 102 Association of DNA polymerase with nucleosomes from mammalian cell chromatin; Schlaeger EJ et al.; More than half of the DNA polymerase beta in mouse ascites cell chromatin was found to be associated with monomeric nucleosomal particles (produced by micrococcal nuclease treatment of chromatin) . Almost all nuclear DNA polymerase activity in lymphocytes was found to be associated with nucleosomes . The nucleosome-associated enzyme was mainly DNA polymerase beta in chromatin from resting and mainly DNA polymerase alpha in chromatin from concanavalin-A-stimulated lymphocytes. Nucleic Acids Res, 1978 Mar, 5(3), 667 - 78 The structure of nucleolar chromatin in Physarum polycephalum; Butler MJ et al.; The nucleolar DNA of Physarum polycephalum has been differentially labelled with 3H-thymidine and the structure of the nucleolar chromatin investigated by digestion with micrococcal nuclease . Nucleolar chromatin which had been labelled in G2 phase of the cell cycle and then digested before mitosis had an identical DNA repeat length to main band DNA (165 +/- 5 base pairs) but there was a definite indication that the rate of digestion was faster for nucleolar DNA than for main band DNA . Nucleolar chromatin which had been labelled in G2 and the label chased through mitosis into G2 phase of the next cycle showed an identical DNA repeat length to main band DNA and was also digested at the same rate . We conclude that nucleolar chromatin, at least 25 per cent of which is maximally transcriptionally active in G2, has a nucleosome-like structure. J Biochem (Tokyo), 1978 Mar, 83(3), 893 - 903 Purification and characterization of lysozyme produced by Streptomyces erythraeus; Morita T et al.; A species of lysozyme (SE lysozyme) was purified from culture filtrate of Streptomyces erythraeus . The enzyme has a molecular weight of 18,500 as determined by ultracentrifugation . Its isoelectric point is 9.5, and it shows optimal activity at pH 4.0 with an optimal ionic strength of 0.1 . Investigation of the substrate specificity showed SE lysozyme to be an N-acetyl-muramidase . The simplest product in the digest of cell walls of Micrococcus lysodeikticus was identified as a disaccharide, {GlcNAcbeta(1 leads to 4) MurNAc} . While S . aureus as well as M . lysodeikticus was lysed by this lysozyme, chitin and its derivatives were not. Can J Microbiol, 1978 Feb, 24(2), 162 - 76 The envelope of Micrococcus radiodurans: isolation, purification, and preliminary analysis of the wall layers; Lancy P Jr et al.; Two methods are presented that separate the complex envelope of Micrococcus radiodurans, strain Sark, into its constituent layers . The first involved treating whole cells with 0.025 M Tris buffer (pH 7.5) containing 2 mM of calcium and 3 mM of magnesium, resulting in the degradation of an intermediate ('compartmentalized') layer and consequent sloughing of the outer subunit and interior layers to form vesicles . This treatment also appears to show that the interior layer may be connected with the peptidoglycan-containing 'holey' layer . The second method involves treating whole cells with benzene followed by sonication; the results suggested that this treatment only released the outer layers from the 'compartmentalized' layer and did not degrade layers . Following benzene treatment, digestion of the 'compartmentalized' layer with cold sodium dodecyl sulfate (SDS) released the 'holey' layer . Electrophoretic analysis of some of the isolated layer preparations suggested that the subunit layer consisted of three major proteins of 90 000, 92 000, and 94 000 molecular weight, one minor protein of 100 000, a small amount of carbohydrate associated with the 94 000 protein, and a small amount of a 55 000 lipoprotein . The interior layer contained at least 10 proteins and may be attached to the peptidoglycan-containing 'holey' layer by means of the 55 000 lipoprotein. Nucleic Acids Res, 1978 Feb, 5(2), 523 - 35 Superstructure and CD spectrum as probes of chromatin integrity; de Murcia G et al.; Two types of chromatin were extracted from the same stock of rat liver nuclei by a short exposure to micrococcal nuclease and by shearing respectively . These two materials which are identical in their protein/DNA content and by the presence of the five histones, were compared by means of circular dichroism and electron microscopy . Under the electron microscope and in absence of any divalent cation a superstructure of the unfixed chromatin fiber can be viewed only with native material but is no more present in sheared one . The increase of CD signal at 280 nm (from 2000 to about 4000 cm2 deg.dmole-1) in the case of sheared chromatin is not related to the loss of superstructure but to the structural changes of DNA inside the nucleosomal core which are always produced by shearing . These two correlated observations offer new sensitive probes of the integrity of any native or reconstituted chromatin. Nucleic Acids Res, 1978 Feb, 5(2), 349 - 62 Chromatin assembly in isolated mammalian nuclei; Shelton ER et al.; Cellular DNA replication was stimulated in confluent monolayers of CV-1 monkey kidney cells following infection with SV40 . Nuclei were isolated from CV-1 cells labeled with {3H}thymidine and then incubated in the presence of {alpha-32P}deoxyribonucleoside triphosphates under conditions that support DNA replication . To determine whether or not the cellular DNA synthesized in vitro was assembled into nucleosomes the DNA was digested in situ with either micrococcal nuclease or pancreatic DNase I, and the products were examined by electrophoretic and sedimentation analysis . The distribution of DNA fragment lengths on agarose gels following micrococcal nuclease digestion was more heterogeneous for newly replicated than for the bulk of the DNA . Nonetheless, the state of cellular DNA synthesized in vitro (32P-labeled) was found to be identical with that of the DNA in the bulk of the chromatin (3H-labeled) by the following criteria: (i) The extent of protection against digestion by micrococcal nuclease of DNase I . (ii) The size of the nucleosomes (180 base pairs) and core particles (145 base pairs) . (iii) The number and sizes of DNA fragments produced by micrococcal nuclease in a limit digest . (iv) The sedimentation behavior on neutral sucrose gradients of nucleoprotein particles released by micrococcal nuclease . (v) The number and sizes of DNA fragments produced by DNase I digestion . These results demonstrate that cellular DNA replicated in isolated nuclei is organized into typical nucleosomes . Consequently, subcellular systems can be used to study the relationship between DNA replication and the assembly of chromatin under physiological conditions. Eur J Biochem, 1978 Feb, 83(2), 615 - 28 Closely spaced nucleosome cores in reconstituted histone.DNA complexes and histone-H1-depleted chromatin; Steinmetz M et al.; It has been demonstrated by digestion studies with micrococcal nuclease that reconstitution of complexes from DNA and a mixture of the four small calf thymus histones H2A, H2B, H3, and H4 leads to subunits closely spaced in a 137 +/- 7-nucleotide-pair register . Subunits isolated from the reconstituted complex contain nearly equimolar amounts of the four histones and sediment at 11.6S . On DNase I digestion both the reconstituted complex and the separated subunits gave rise to series of single-stranded DNA fragments with a 10-nucleotide periodicity . This indicates that the reconstitution leads to subunits very similar to nucleosome cores . Nucleosome cores closely spaced in a 140-nucleotide-pair register were also obtained upon removal of histone H1 from chromatin by dissociation with 0.63 M NaCl and subsequent ultracentrifugation . In reconstitution experiments with all five histones (including histone H1) our procedure did not lead to tandemly arranged nucleosomes containing about 200 nucleotide pairs of DNA . In the presence of EDTA, DNase II cleaved calf thymus nuclei and chromatin at about 200-nucleotide-pair intervals whereas in the presence of Mg2+ cleavage at intervals of approximately half this size was observed . The change in the nature of the cleavage pattern, however, was no longer found after removal of histone H1 from chromatin . This indicates that H1 influences the accessibility of DNase II cleavage sites in chromatin . This finding is discussed with respect to the influence of histone H1 on chromatin superstructure. Biochem J, 1978 Feb 1, 169(2), 371 - 80 Thermal denaturation of Micrococcus lysodeikticus adenosine triphosphatase . Influence of temperature on the circular dichroism, fluroescence and enzymic activity of the protein; Ayala JA et al.; The soluble ATPase (adenosine triphosphatase) from Micrococcus lysodeikticus underwent a major unfolding transition when solutions of the enzyme at pH 7.5 were heated . The midpoint occurred at 46 degrees C when monitored by changes in enzymic activity and intrinsic fluorescence, and at 49 degrees C when monitored by circular dichroism . The products of thermal denaturation retained much secondary structure, and no evidence of subunit dissociation was detected after cooling at 20 degrees C . The thermal transition was irreversible, and thiol groups were not involved in the irreversibility . The presence of ATP, adenylyl imidodiphosphate, CaCl2 or higher concentrations of ATPase conferred stability against thermal denaturation, but did not prevent the irreversibility one denaturation had taken place . In the presence of guanidinium chloride, thermal denaturation occurred at lower temperatures . The midpoints of the transition were 45 degrees C in 0.25 M-, 38 degrees C in 0.5 M-and 30 degrees C in 0.75 M-denaturant . In the highest concentration of guanidinium chloride a similar unfolding transition induced by cooling was observed . Its midpoint was 9 degrees C, and the temperature of maximum stability of the protein was 20 degrees C . The discontinuities occurring the the Arrhenius plots of the activity of this enzyme had no counterpart in variations in the far-u.v . circular dichroism or intrinsic fluorescence of the protein at the same temperature. Eur J Biochem, 1978 Jan 2, 82(1), 199 - 209 Characteristics of a coupled cell-free transcription and translation system directed by vaccinia cores; Pelham HR et al.; 1 . A coupled transcription and translation system is described in which protein synthesis is directed by mRNA synthesised in situ by vaccinia virus cores . The cell-free system is based on a micrococcal-nuclease-treated reticulocyte lysate . 2 . The polypeptides made in vitro include many authentic early vaccinia proteins, but also other proteins which were not detected in infected cells . 3 . Concentrations of cores which inhibit host cell protein synthesis in vivo caused a delayed inhibition of translation in vitro; this was partly, but not entirely, due to dsRNA associated with the cores . 4 . The mRNA made was methylated by core enzymes . Inhibition of methylation reduced the rate of translation tenfold; unmethylated RNA bound ribosomes poorly, but was nevertheless translated faithfully. Zentralbl Bakteriol Naturwiss, 1978, 133(6), 533 - 6 Effect of antibiotics, non-ionic detergents, and vitamins on the osmotic barriers of Micrococcus glutamicus; Zaki D et al.; The production of amino acids by the mutant strain, homoserine methionine deficient, of Micrococcus glutamicus, was studied through the elucidation of the role of chemical agent affecting the osmotic barriers . Penicillin was found to affect the cell wall integrity and to increase greatly the total amino acid content, especially in presence of high biotin content . Non-ionic detergents were found to affect the integrity of cytoplasmic membrane . The effect was not similar with the different types of detergents and not proportional to the increase of its concentration. Microbiol Immunol, 1978, 22(8), 453 - 62 Process of consecutive cell divisions and separations in a regular tetrads-forming mutant of Micrococcus lysodeikticus (luteus); Monodane T et al.; A mutant MT of Micrococcus lysodeikticus (luteus) I