Micrococci

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) IFO 3333, whose minimum growing unit is not a single cell, but a tetrad unlike the wild-type divides by binary fission of each monococcus, and then separates first into two daughter tetrads, second into four tetrads and third into eight tetrads . The three planes of either the cell division or the cell separation are equivalent to one another and oriented at right angles in three dimensions, respectively . The process of consecutive cell divisions and separations of the mutant tetrads was schematically illustrated.

Microbiol Immunol, 1978, 22(2), 67 - 80
Demonstration of the physiological role of autolysis by a comparative study with a wild-type and its non-autolytic mutant of Micrococcus lysodeikticus (luteus) cultivated with externally added proteolytic enzymes; Monodane T et al.; The log phase cells of autolytic Microccus lysodeikticus (luteus) IFO 3333 did not autolyze when grown in the presence of trypsin although the growth curve and morphology of the cells were not influenced . A non-autolytic mutant was obtained by subculture of the wild-type strain IFO 3333 on an agar slant containing 1% glucose . The mutant (strain MT) was wild-type IFO 3333 which occurred singly or in irregular masses . The mutant MT grown in a culture medium containing trypsin caused remarkable alteration in cell morphology: large cell packets consisting of a number of "unit tetrads" arranged regularly in three dimensions were formed by the addition of trypsin to the medium . The findings suggest that inhibition of the separation of divided cells is brought about by inactivation or suppression of a cell wall autolytic enzyme which plays an important role in the separation step and is accessible to externally added trypsin in the mutant cells but not in the wild-type cells . The possibility that there are two kinds or phases of autolytic enzymes "a physiological autolytic enzyme" and "a useless autolytic enzyme", is discussed.

Nucleic Acids Res, 1978 Jan, 5(1), 71 - 85
Proximity and accessibility studies of histones in nuclei and free nucleosomes; Bonner WM; Histone proximity in chromatin was studied with the cleavable crosslinking reagent, dithiobissuccinimidyl propionate . Crosslinks between H4 and H2a, H4 and H2b, H4 and H3, H2a and H2b, H2b and H3 were found . H1 is also crosslinked to the nucleosomal histones . In nuclei, unsheared chromatin, and H1 depleted chromatin, the four nucleosomal histones are crosslinked at similar relative rates both in 5 mM salt and 100 mM salt . After micrococcal nuclease treatment to generate nucleosomes, H2a and H2b are crosslinked faster than H4 and H3 . C14-NEM titration of thiopropionate residues bound to each histone shows that H2a and H2b are more accessible to this reagent after nuclease treatment but that the increased binding was not sufficient by itself to explain the increase in crosslinking . Bolton Hunter reagent was used to further study the accessibility of the four nucleosomal histones in whole chromatin and nuclease digested chromatin . These studies showed that salt increases the accessibility of all four histones while nuclease treatment decreases H4 accessibility.

Curr Top Radiat Res Q, 1978 Jan, 12(1-4), 369 - 88
Repair of the double-strand breaks produced by 125I disintegrations in the DNA of Micrococcus radiodurans; Myers DK; Wild-type M . radiodurans and two radiosensitive mutants were used to study the lethal effects of 125I disintegrations in their DNA . The relative sensitivities of these three strains to inactivation by gamma-radiation were reflected in their relative sensitivities to inactivation by 125I decay . The number of double-strand (ds) breaks in the DNA appeared to be similar at levels of gamma-radiation and of 125I decay that reduced survival to 10% . All three strains of M . radiodurans rapidly repaired ds breaks produced in their DNA by either gamma-radiation or 125I disintegrations . If one ds break per is a lethal event {Kirsch et al., 1975}, cells of the three strains tested would die only when they had left unrepaired one ds break out of an initial 45,600 or 1800 ds breaks per single cell.

J Clin Pathol, 1978 Jan, 31(1), 39 - 43
Complex nature of serum lysozyme activity: evidence of thermolability in inflammatory bowel disease; Ward M et al.; In patients with Crohn's disease and ulcerative colitis, alterations in serum storage temperature produced significant changes in serum lysozyme activity (SLA) as measured by the lysoplate method . This was not the case in healthy controls or in a group with other gastrointestinal disorders . Electrophoretic separation of serum revealed two components of lysozyme-type lytic activity but only one in extracts of gut mucosa, leucocytes, and egg white . The major lytic component of serum migrated towards the cathode and reacted with specific antilysozyme serum, but the minor component which migrated towards the anode did not . Although the cause of this anionic lytic activity is uncertain, it contributes to total serum activity as estimated by any method utilising the lysis of Micrococcus lysodeikticus, and may possibly be related to the observed thermolability.

Biophys Chem, 1978 Jan, 7(4), 317 - 23
Pulse fluorimetry study in polarized light of DNA-ethidium bromide complexes; Genest D et al.; In previous works, a quantitative analysis of the fluorescence anisotropy decay, based on a comparison of the experimental measurements with a Monte Carlo simulation of the excitation energy migration, has been shown to provide the value of the unwinding angle of the DNA helix, induced by an ethidium bromide (E.B.) molecule intercalation . In the present work some of the characteristics of the model used in the computation are reexamined: namely the influence of the direction of the E.B . electronic moment, and the influence of the dye distribution along the DNA helix are studied . The computations are compared with experimental results obtained with new experiments performed with calf thymus and micrococcus lysodeikticus DNA-E.B . complexes . It is found that the difference in base composition of these DNA does not influence the fluorescence properties of their E.B . complexes . Our study confirms the validity of the dye distribution obtained with the single adjacent excluded site principle . Reasonable values of the unwinding angle are obtained by assuming that the transition moment direction lies along the great axis of the E.B . molecule . The value of this unwinding angle is compared with other values proposed in the literature.

Appl Environ Microbiol, 1978 Jan, 35(1), 1 - 5
Upper boundary of the biosphere; Imshenetsky AA et al.; By using meterological rockets fitted with specially designed analyzers, samples for microbiological investigation have been taken . The analyzer design prevented extraneous microorganisms from penetrating into the analyzer . Before being used, the analyzers were sterilized with high gamma-ray doses . For the first time microorganisms have been detected in the mesosphere at an altitude of 48 to 77 km . The microorganisms are microscopic fungi having black conidia or spores (Circinella muscae, Aspergillus niger, Papulaspora anomala) and one species forming green conidia (Penicillium notatum) . Colonies of Mycobacterium luteum and Micrococcus albus have also grown . Five of the six species have synthesized pigments . The presence of pigmented microbial forms leads us to believe that natural selection is occurring in the mesosphere because cells possessing chromogenous pigments (carotenoids, melanins) are more resistant to ultraviolet-ray action . A greater number of microorganisms have been registered in the mesosphere during dust storms than in the absence of strong winds.

IARC Sci Publ, 1978, (24 Pt 1), 347 - 51
Cell-free systems for in vitro translation of herpes simplex virus messenger RNA; Preston CM; A cell-free system active in translation of HSV mRNA was obtained by fractionation of reticulocyte lysates . Endogenous protein synthesis was further reduced by preincubation with micrococcal nuclease, although this treatment did not affect the translation of infected (or uninfected) BHK cell RNA . Polypeptides synthesized by the fractionated reticulocyte cell-free system were very similar to those produced by unfractionated reticulocyte lysates.

J Virol, 1978 Jan, 25(1), 175 - 86
Comparison of nuclease digestion of polyoma virus nucleoprotein complex and mouse chromatin; Ponder BA et al.; We digested polyoma virus nucleoprotein complex, isolated from disrupted virions, with micrococcal nuclease and DNase I . The results were compared with digestions of chromatin from mouse nuclei . The nucleosome "core" structures were similar, but the spacing of the nucleosomes in the isolated polymoma nucleoprotein complexes was irregular, whereas in mouse chromatin it was regular . The average nucleosome repeat length in each case was 190 to 200 base pairs . This figure suggests that, unless there are substantial stretches of free DNA, the polyoma nucleoprotein complex contains about 26 nucleosomes . The commonly used method of preparing the nucleoprotein complex by disruption of virions at pH 10.2 may lead to significant damage to the structure . Such damage may be more clearly revealed by the susceptibility of the DNA to nuclease digestion than by the usual criteria of sedimentation velocity and buoyant density.

Microbiol Immunol, 1978, 22(2), 57 - 66
Cell wall autolysis in log phase cells of Micrococcus lysodeikticus (luteus); Monodane T et al.; Log phase cells of Micrococcus lysodeikticus (luteus) IFO 3333 autolyzed when incubated at 37 C in 0.01 M sodium-phosphate buffer pH 7.5 . The enzyme involved in the autolysis was recovered mainly in an aqueous phase from cytoplasmic membranes and cytoplasmic materials treated with n-butanol, and proved to be an N-acetylmuramyl-L-alanine amidase . The autolysis of log phase cells suspended in autolyzing buffer was depressed by the addition of trypsin to the buffer.

Rev Rhum Mal Osteoartic, 1977 Dec, 44(12), 741 - 7
{Synovectomy in the treatment of acute arthritis caused by Micrococcus pyogenes}; Gerard Y et al.; In addition to antibiotic therapy associated with immobilization in a plaster cast, effective in the majority of cases of acute arthritis caused by St . pyogenes and resection-arthrodesis which is necessary in the stage of osteoarthritis, synovectomy occupies an intermediate position . During a period--possibly not a short one--when the lesions are still purely synovial and do not regress under medical treatment, their ablation permits recovery from the infection with restoration of the functional activity of the joint . The experience is based on 26 observations (19 knees, 3 hips, 2 shoulders, 1 thumb, 1 metacarpo-phalangeal lesion) . In 2/3 of cases these arthritides were iatrogenic (13 after cortisone infiltration, 4 postoperative, 1 haematogenic from i.v . catheterization) . Synovectomy should be complete; haemostasis must be rigorous; an aspiration drain is left in place for 5 or 6 days; additional immobilization in plaster is not obligatory; antibiotic treatment is continued until the BSR has returned to normal . As regards control of the infection, this was obtained in 19 of 26 operations . As regards function, in 10 of these cases the results were very good, in 7 good (slight persistent restriction of movement), in only 2 cases the results were unsatisfactory . The factors that appear to affect the results are on the one hand rigorous technique and on the other sufficiently early operation before the lesions have become too fully established . However, a study of arthritides after cortisone infiltration of previously affected joints has shown that even relatively late operation can lead to satisfactory results (9 of 13).

Nucleic Acids Res, 1977 Dec, 4(12), 4077 - 89
Isolation and characterization of a spacerless dinucleosome from H1-deleted chromatin; Klevan L et al.; Calf thymus chromatin, depleted in histone H1, was digested with micrococcal nuclease and fractionated by column chromatography . 140 base pair nucleosome core particles were isolated along with an unusual particle containing 2 histone octamers and 240 base pairs of DNA . Evidence is presented that the spacer DNA region is absent from these modified dinucleosomes, which appear as stable products of the digestion process . The physical properties of both particles are presented along with brief speculation on their possible origin and function.

Biokhimiia, 1977 Dec, 42(12), 2099 - 104
{Variation of cell membrane lipid composition by means of lipid transfer proteins . Properties of the protoplast membrane of Micrococcus lysodeikticus after incorporation of phosphatidylcholine}; Barsukov LI et al.; After incorporation of phosphatidylcholine (PC) into the protoplast membrane of M . lysodeikticus by protein mediated transfer from PC liposomes, the activity of some membrane bound respiratory chain enzymes was studied . It was found that incorporation of PC decreases the rates of oxidation of exogenous substrates (NADH, malate) but the level of endogenous respiration was not changed . Ferricyanidreductase activity of ghosts of M . lysodeikticus was not dependent upon the PC content of protoplasts . PC containing protoplasts showed a higher osmotic stability than unmodified protoplasts . It is concluded that the incorporation of PC into the protoplasts results in resealing, i . e . in the repair of local defects in the protoplast membrane.

Antibiotiki, 1977 Dec, 22(12), 1063 - 5
{Biological characteristics of culture 6734-21 and the conditions for isolating the antiviral antibiotic it produces}; Fadeeva NP et al.; An actinomyceteous strain No . 6734-21 was isolated from a soil sample of Central Asia and classified as Actinomyces bottropensis . It inhibited the development of the phage of the lysogenic culture of Micrococcus lysodeicticus 53-40 (No . 5) and the variolovaccine DNA-containing virus . Actinomyces bottropensis, strain No . 6734-21 produced an antiviral antibiotic classified as one belonging to the actinorodine group.

Hoppe Seylers Z Physiol Chem, 1977 Dec, 358(12), 1591 - 603
Purification and characterization of the DNA-dependent RNA polymerase and its subunit sigma from Micrococcus luteus; Lill UI et al.; DNA-dependent RNA polymerase from Micrococcus luteus can be isolated from cell extracts after removal of an excess of nucleic acids by fractionation with ammonium sulfate, followed by two consecutive gel filtrations through agarose and chromatography on cellulose phospate . Either homogeneous holoenzyme or a mixture of core and holoenzyme is obtained in this way, as is indicated by electrophoresis in polyacrylamide gels in the absence of detergent, where core enzyme migrates ahead of holoenzyme . Homogeneous core enzyme can be isolated from holoenzyme by chromatography on DEAE-cellulose . Core enzyme contains the subunits alpha, beta and beta' previously described {U.I . Lill et al., (1975) Eur . J . Biochem . 52, 411-420} in a molar ratio of 2:1:1 . Holoenzyme contains an additional subunit sigma of 80 000 molecular weight (molar subunit composition alpha2 betabeta' sigma) and two relatively small polypeptides (molecular weight 14 000 and 25 000, respectively) . Subunit sigma may be isolated from holoenzyme by chromatography on DEAE-cellulose at pH 6.9 in the presence of low concentrations of glycerol . The behaviour of holoenzyme during sedimentation in a glycerol gradient at low ionic strength indicates its occurrence as a dimer of the alpha2betabeta'sigma-protomer, whereas the monomeric form is preferred by core enzyme . Holoenzyme is much more active than core enzyme in RNA synthesis on bacteriophage T4DNA as template . The activity of the latter is stimulated by isolated sigma . M . luteus sigma as well as holoenzyme enhances also the activity of core enzyme fro- Escherichia coli . The formation of a hybrid between micrococcal sigma and E . coli core polymerase is also suggested by the influence of sigma on the oligomerisation of the enzyme from E . coli.

Hoppe Seylers Z Physiol Chem, 1977 Dec, 358(12), 1605 - 8
Formation of a RNA polymerase sub-assembly composed of subunit alpha from Escherichia coli and of subunit beta from Micrococcus luteus; Lill UI et al.; Functionally equivalent subunits of RNA polymerase from Micrococcus luteus and Escherichia coli differ from each other in many molecular and antigenic properties . In spite of these differences, subunit alpha from E . coli and subunit beta from M . luteus form a complex alpha2beta, when incubated together . This complex binds rifampicin tightly, which the isolated subunits do not . The hybrid complex is very similar in its properties to the complex alpha2beta formed only from E . coli or M . luteus subunits . Since the sub-assembly alpha2beta from E . coli is reported to be an obligatory intermediate in the assembly process of complete RNA polymerase, the newly described hybrid sub-assembly may function similarly as an intermediate in the formation of the hybrid form of RNA polymerase described earlier.

Proc Natl Acad Sci U S A, 1977 Dec, 74(12), 5579 - 83
DNA degradation in terminally differentiating lens fiber cells from chick embryos; Appleby DW et al.; During the terminal differentiation of lens fiber cells, nuclear DNA is known to accumulate free 3'-OH ends and is progressively lost from the nucleus . Toward the end of this process, nuclei undergo pycnosis and disappear . The size of the DNA in the epithelia and in early and late stages of fiber cell development was examined by electrophoresis on nondenaturing agarose/polyacrylamide gels . Low molecular weight DNA of discrete sizes appears only at the final stages of nuclear degeneration in central fiber cells and persists after the disappearance of the nuclei . These low molecular weight DNA fragments appear as multiples of a monomeric unit and are similar to the fragments produced by the digestion of epithelial cell nuclei by micrococcal nuclease . The data indicate that in lens fiber nuclei the double-strand breaks in vivo affect the chromatin during nuclear degeneration, and the data suggest that the DNA of these cells is organized into chromatin composed of discrete subunits.

Proc Natl Acad Sci U S A, 1977 Dec, 74(12), 5492 - 5
Presence of protein A24 in rat liver nucleosomes; Goldknopf IL et al.; Two-dimensional gel profiles of the 0.2 M H2SO4-soluble proteins of monomer nucleosomal fractions were found to contain protein A24 . Protein A24 is of interest because it is composed of histone 2A and "ubiquitin", apparently joined by an isopeptide linkage {Goldknopf, I.L . & Busch, H . (1977) Proc . Natl . Acad . Sci . USA 74, 864-868; Hunt, L.T . & Dayhoff, M.O . (1977) Biochem . Biophys . Res . Commun . 74, 650-655} . Monomer nucleosomal fractions were obtained by sucrose density gradient centrifugation of micrococcal nuclease digests of rat liver nuclei . As shown by their DNA size, the monomer fractions were highly purified . Proteins A24 and Bu, another protein of unknown characteristics, were found along with histones 1, 2A, 2B, 3, and 4 in the monomer fractions in relative amounts similar to those found in extracts from whole nuclei and chromatin . Other acid-soluble proteins found in the nuclear and chromatin extracts were essentially absent from the monomer fraction . Inasmuch as protein A24 and Bu were found in lesser amounts than the histones, it is suggested that they are associated with specialized subsets of nucleosomes.

Nucleic Acids Res, 1977 Dec, 4(12), 4235 - 47
DNA-relaxing enzyme from Micrococcus luteus; Hecht R et al.; A DNA-relaxing enzyme which catalyzes the conversion of superhelical DNA to a non-superhelical covalently closed form has been purified from Micrococcus luteus to near homogeneity by two chromatographic steps . The enzyme is a single polypeptide chain . As determined by sodium dodecyl sulfate - polyacrylamide gel electrophoresis and gel filtration on Sephadex G 150, the molecular weight is 115,000 . The DNA-relaxing activity determined as a function of enzyme concentration follows a sigmoidal curve . The enzyme requires Mg++ for activity . In the presence of 4.5 mM Mg++ addition of 50-250 mM KCl yields incompletely relaxed DNA molecules (intermediates); intermediates are also observed in the absence of KCl, when the reaction is carried out at 0 degree C or at Mg++ concentrations exceeding 10 mM.

Biochemistry, 1977 Nov 29, 16(24), 5295 - 303
Reconstitution of chromatin core particles; Tatchell K et al.; Chromatin core particles, containing 140 base pairs (bp) of DNA plus the inner histones, can be nearly quantitatively formed either by reassociation from 2 M NaCl or by reconstitution from salt extracted histones and DNA . The reassociated or reconstituted particles appear to be identical with the native particles in all physical properties examined (sedimentation velocity, histone content, circular dichroism, and melting) as well as in their patterns of digestion by micrococcal nuclease, DNase I, and trypsin . In the presence of excess DNA, no "half-particles" are formed . In the presence of excess histone, aggregated structures are formed in addition to 11S core particles.

J Biol Chem, 1977 Nov 25, 252(22), 8269 - 77
Heterogeneity in nucleosome spacing; Martin DZ et al.; The organization of spacer DNA connecting 160 base-pair cores of bovine thymus polynucleosomes has been studied by a combination of biochemical and electron microscopic techniques . The results reveal that a major fraction of chromatin consists of a spectrum of repeating units; these differ from each other by up to 20 base-pairs due to variation in spacer DNA length . Those polynucleosomes which have larger spacer DNA lengths are processed by micrococcal nuclease to mononucleosomes more rapidly than those organized with shorter spacers . Although a distribution of spacer DNA lengths exists, a significant proportion of spacers that are nearest neighbors share common DNA lengths . These findings imply that functional roles may be related to the manners in which spacers are organized along chromatin fibers.

Eur J Biochem, 1977 Nov 15, 81(1), 103 - 9
F1-ATPase from Micrococcus sp . ATCC 398 . Purification by ion-exchange chromatography and further characterization . (Auto)proteolysis and dissociative effects; Risi S et al.; The preparation of highly purified F1-ATPase from Micrococcus sp . ATCC 398 by application of DEAE-Sepharose CL-6B chromatography as final step is described . This enzyme consists of five subunits of different molecular weight: alpha (65000), beta (55000),gamma (35000), delta (20000), and epsilon (17000) . Disc electrophoresis on 5% polyacrylamide gels removes the epsilon-polypeptide yielding an active ATPase complex with four different subunits: alpha, beta, gamma, delta . Additionally, by variation of the ionic strength delta can (partly) removed allowing the isolation by disc electrophoresis of an active ATPase complex which consists only of three different subunits alpha, beta, and gamma . If the DEAE-Sepharose chromatography is carried out in the absence of diisopropyl phosphofluoridate (auto)proteolysis yields both an active ATPase with the subunits alpha+ (mol . wt 61000), beta, gamma, and delta and an inactive protein complex with the subunits alpha+, beta, gamma, delta, and two additional polypeptides a (mol . wt 38000) and b (mol . wt 23000) . The latter two polypeptides are supposedly fragments of alpha+-chains which have become partially cleaved by (auto)proteolysis.

Eur J Biochem, 1977 Nov 1, 80(2), 453 - 9
Maintenance of the ratio of alpha and beta globin synthesis in rabbit reticulocytes; Stewart AG et al.; The synthesis of rabbit alpha and beta globins under various conditions was studied using intact reticulocytes and reticulocyte cell-free systems . Raising salt concentration of media in which reticulocytes were incubated with radioactive amino acids reduced the total protein synthesis but did not affect the ratio of alpha to beta globins produced . Using a reticulocyte lysate which had been incubated with micrococcal nuclease to remove the endogenous globin messenger RNA activity, it was found that unlike the intact cell or the untreated lysate very little alpha globin was synthesised on adding purified globin mRNA . These results are discussed in terms of their compatibility with some proposed models of coordination of alpha and beta globin production.

Biochemistry, 1977 Nov 1, 16(22), 4940 - 4
Histone composition of nucleosomes isolated from cultured Chinese hamster cells; Rall SC et al.; Nuclei isolated from cultured Chinese hamster cells were treated with micrococcal nuclease and lysed, and the resulting chromatin subunit classes (nucleosomes) were purified by sedimentation and resedimentation through isokinetic sucrose gradients . Nucleosomes isolated from {3H}thymidine-labeled cells were analyzed for DNA size using both polyacrylamide gel and electron microscopic techniques . Nucleosomes isolated from {14C}lysine-labeled cells were analyzed for protein content using a sodium dodecyl sulfate-polyacrylamide gel system . The results from monitoring the {14c}lysine in each protein indicate that, in the nucleosome classes (monomer through tetramer), the molar ratios of histones H2A, H2B, H3, and H4 are equivalent . Furthermore, in each population of the nucleosome classes monomer through tetramer, it was possible to demonstrate that this histone unit (H2A + H2B + H3 + H4) is present, on the average, in the amount of two for monomers, four for dimers, six for trimers, and eight for tetramers . This is direct experimental confirmation of the prediction of R.D . Kornberg {(1974) Science 184, 868} concerning the substructure of chromatin.

Proc Natl Acad Sci U S A, 1977 Nov, 74(11), 5126 - 30
Idiotypic regulation of the immune system by the induction of antibodies against anti-idiotypic antibodies; Urbain J et al.; Anticarbohydrate antibodies (Ab1) were isolated from a rabbit hyperimmunized with Micrococcus lysodeikticus and injected into allotype-matched rabbits in order to obtain specific anti-iodiotypic antibodies (Ab2) . Ab2 was isolated by means of a Sepharose column coupled to the anticarbohydrate antibodies and was injected into two allotype-matched rabbits . These latter rabbits produced specific anti-anti-idiotypic antibodies (Ab3) probably sharing idiotypic specificities with Ab1 . However, these Ab3 did not react with the antigenic carbohydrate moiety of bacteria . The two rabbits that had produced Ab3 were then immunized with M . lysodeikticus and synthesized anticarbohydrate antibodies (Ab1') bearing idiotypic specificities similar to those of Ab1 . The immune repertoire which is effectively expressed in one individual depends not only on the antigenic stimulation but also on the previous idiotypic history of the individual . These data support the concept that the immune system is a functional idiotypic network.

Biochemistry, 1977 Oct 18, 16(21), 4616 - 22
Solanesyl pyrophosphate synthetase from Micrococcus lysodeikticus; Sagami H et al.; Solanesyl pyrophosphate synthetase from extracts of Micrococcus lysodeikticus was purified by DEAE-Sephadex, hydroxylapatite, and Sephadex G-100 chromatography . This enzyme was found to catalyze the trans condensation of isopentenyl pyrophosphate with geranyl pyrophosphate to afford all-trans-octaprenyl (C40) and alltrans-nonaprenyl (C45) pyrophosphate without accumulation of prenyl pyrophosphate with chain length shorter than C40 . all-trans-Farnesyl and all-trans-geranylgeranyl pyrophosphate also were active as cosubstrates, though they were less effective than geranyl pyrophosphate . However, neither dimethylallyl nor cis,trans,trans-geranylgeranyl pyrophosphate was active . The molecular weight of this enzyme was estimated to be 78 000 by Sephadex G-100 filtration . An enzyme preparation from young shoots of potato was found to hydrolyze the polyprenyl pyrophosphates effectively to give the corresponding prenols.

Nucleic Acids Res, 1977 Oct, 4(10), 3617 - 26
DNA associated with nucleosomes in plants; Philipps G et al.; 50 to 55% of tobacco and barley nuclear DNA is accessible to micrococcal endonuclease digestion . The DNA fragments resulting from a mild endonuclease treatment are multiples of a basic unit of 194 +/- 6 base pairs in tobacco and 195 +/- 6 base pairs in barley . After extensive digestion, a DNA fragment of approximately 140 base pairs is predominant . Hence the "extra-core" or "linker"-DNA is 55 base pairs long . Other fragments having 158 and less than 140 base pairs are present as well . Treatment with DNase I results in multiples of 10 bases when analysed under denaturating conditions . These results show that the general organization of the DNA within the nucleosomes is about the same in higher plants as in other higher eukaryotes.

Nucleic Acids Res, 1977 Oct, 4(10), 3581 - 7
Highly efficient translation of messenger RNA in cell-free extracts prepared from L-cells; Skup D et al.; Micrococcal nuclease was used to eliminate endogenous protein synthesis in extracts prepared from L cells . The nuclease can be inhibited subsequently with 2'-deoxythymidine-3', 5'-diphosphate . Nuclease-treated extracts primed with exogenous reovirus mRNA, synthesized full length polypeptides with linear kinetics for almost two hours leading to stimulation of the order of 10(4) times over endogenous background . On the average, between 40 and 50 molecules of polypeptide were synthesized per molecule of mRNA.

Nucleic Acids Res, 1977 Oct, 4(10), 3281 - 301
Distribution of H1 histone in chromatin digested by micrococcal nuclease; Gaubatz JW et al.; The relative amount of H1 histone associated with isolated nucleosomes from calf thymus was determined as a function of the extent of DNA digestion by micrococcal nuclease . Generally the amount of H1 histone associated with mononucleosomes decreases with increasing digestion until 60% of the original H1 remains associated with DNA 150 base pirs or less in size . Coincidentally, H1 histone increases relative to the other histones in aggregated material that sediments through sucrose gradients to form a pellet . However, the level of H1 histone remains at control values for oligonucleosomes (dimer to hexamer) over the 30% digestion range studied . An increase in ionic strength to 0.3 M NaCl in the density gradient reveals a different pattern of H1 binding, whereby the amount of H1 reflects the average size of the DNA fragments with which it is associated . Although there is significant binding to nucleosomes per se, it appears that the major ionic involvement of H1 is with internucleosomal spacer DNA.

Cell, 1977 Oct, 12(2), 409 - 15
Selective release of chromosomal proteins during limited DNAase 1 digestion of avian erythrocyte chromatin; Vidali G et al.; Duck erythrocyte chromatin has been treated with DNAase 1 under conditions that are known to digest selectively the structural genes coding for globin mRNAs . This limited digestion releases specific sets of nonhistone chromosomal proteins that are not preferentially released during limited digestion with micrococcal nuclease, which does not selectively attack the globin sequences . Analysis of nucleosome monomer and multimer peaks separated on sucrose gradients after limited digestion with micrococcal nuclease shows that the proteins which are released by DNAase 1 digestion remain associated with the chromatin subunits and can be removed by extraction in 0.5 M NaCl . These proteins are tentatively identified as members of the high mobility group (HMG) proteins (originally described by Goodwin, Sanders and Johns, 1973) in terms of their extractability, electrophoretic characteristics and amino acid composition.

Mutat Res, 1977 Oct, 45(1), 13 - 20
Repair of pyrimidine dimers in radiation-sensitive mutants rad3, rad4, rad6 and rad9 of Saccharomyces cerevisiae; Prakash L; The ability to remove ultraviolet (UV)-induced pyrimidine dimers was examined in four radiation-sensitive mutants of Saccharomyces cerevisiae . The susceptibility of DNA from irradiated cells to nicking by either the T4 UV-endonuclease or an endonuclease activity found in crude extracts of Micrococcus luteus was used to measure the presence of dimers in DNA . The rad3 and rad4 mutants are shown to be defective in dimer excision whereas the rad6 and rad9 mutants are proficient in dimer excision.

J Biol Chem, 1977 Sep 25, 252(18), 6294 - 8
Micrococcus luteus correndonucleases . III . Evidence for involvement in repair in vivo of two endonucleases specific for DNA containing pyrimidine dimers; Riazuddin S et al.; Involvement of Py pyrimidine dimers Py correnconucleases I and II in repair of ultraviolet radiation damage in vivo by Micrococcus luteus has been demonstrated by their absence in the ultraviolet-sensitive mutant DB-7 derived by treatment of the wild type parent with N-methyl-N'-nitro-N-nitrosoguanidine . The necessity for their combined action in DNA repair in M . luteus is shown by: (a) reactivation of ultraviolet-damaged phiX174 RFI DNA in incision-defective hosts after in vivo treatment with both enzymes, (b) correlation between survival after ultraviolet irradiation and the level of the two enzymes, and (c) increased levels of repair synthesis after ultraviolet irradiation of toluenized cells DB-400 with wild type correndonuclease levels when compared with the transformant DB-200 and the mutant DB-7, which lack one or both enzymes.

J Biol Chem, 1977 Sep 25, 252(18), 6280 - 6
Micrococcus luteus correndonucleases . I . resolution and purification of two endonucleases specific for DNA containing pyrimidine dimers; Riazuddin S et al.; Five peaks of endonuclease activity showing a preference for ultraviolet-damaged DNA have been chromatographically identified from extracts of Micrococcus luteus . They are numerically designated as I to V in order of their elution from phosphocellulose (Whatman P-11) columns . The first two of these peaks have been highly purified by a combination of gel filtration and affinity chromatography and are catalytically homogeneous judging from their effect on transforming DNAs . Peak I, which has an isoelectric point of 4.7, is heat-stable, requires high ionic strength for optimal activity, acts with equal facility on ultraviolet-irradiated native and denatured DNA, and has been designated as Py pyrimidine dimer Py correndonuclease I . Peak II which has a pI value of 8.7, is heat-labile, is inhibited by high ionic strength, acts on ultraviolet-irradiated native but not denatured DNA, and has been designated as Py pyrimidine dimer Py correndonuclease II . Both enzymes are inhibited by Ca2+ and Zn2+, do not show any cofactor or sulfhydryl requirement, act optimally between pH 7.0 and 7.4, and have molecular weights between 11,000 and 15,000 . Py pyrimidine dimer Py correndonuclease I requires a dose about 1.6 times that for Py pyrimidine dimers Py correndonuclease II for incision saturation of irradiated phiX174 RFI DNA.

J Biol Chem, 1977 Sep 25, 252(18), 6287 - 93
Micrococcus luteus correndonucleases . II . Mechanism of action of two endonucleases specific for DNA containing pyrimidine dimers; Riazuddin S et al.; Py pyrimidine dimers Py correndonucleases I and II from Micrococcus luteus act exclusively on thymine-thymine, cytosine-cytosine, and thymine-cytosine cyclobutyl dimers in DNA, catalyzing incision 5' to the damage and generating 3'-hydroxyl and 5'-phosphoryl termini . Both enzymes initiate excision of pyrimidine dimers in vitro by correxonucleases and DNA polymerase I . The respective incised DNAs, however, differ in their ability to act as substrate for phage T4 polynucleotide ligase or bacterial alkaline phosphatase, suggesting that each endonuclease is specific for a conformationally unique site . The possibility that their respective action generates termini which represent different degrees of single strandedness is suggested by the unequal protection by Escherichia coli binding protein from the hydrolytic action of exonuclease VII.

J Biol Chem, 1977 Sep 10, 252(17), 5962 - 6
Chromatin subunits contain normal levels of major acetylated histone species; Davie JR et al.; Chromatin subunits or nucleosomes prepared by micrococcal nuclease digestion of nuclei from trout testis have been examined for the presence of in vivo modified histone species . Both monomers and multimers are labeled when testis cells are incubated in the presence of {14C}acetate, but the level of radioactivity in the monomer fraction is 10 to 20% higher than in the multimer fraction . This difference is attributed to the trimming of nucleotides from the monomer DNA, associated with the loss of H1 . The specific activities of the {14C}acetate label in histones H2A, H2B, H3, and H4 in monomer particles are similar to their respective values in whole chromatin . Starch gel electrophoresis of histone fractions derived from monomeric nucleosomes revealed the presence of monoacetylated and phosphorylated species of H2A, monoacetylated species of H2B and H3, and mono-, di-, tri-, and tetraacetylated species of H4 . No differences in the content of these species between monomeric nucleosomes and whole chromatin could be discerned.

Nucleic Acids Res, 1977 Sep, 4(9), 3097 - 108
Methylation of nucleosomal and nuclease sensitive DNA; Adams RL et al.; The proportion of cytosines methylated in the DNA of nucleosome oligomers and of core particles appears indistinguishable from that of total nuclear DNA from CHO cells . However the DNA in nucleoprotein which is initially released from nuclei by treatment with very low levels of micrococcal nuclease and the first 10% of material rendered acid soluble by treatment of nuclei with DNase I are enriched 2 fold in their content of 5 methylcytosine . (Cessation of hydrolysis by nuclease occurs concomitantly with precipitation of nucleosomal core particles).

Cancer Res, 1977 Sep, 37(9), 3243 - 8
Induction and persistence of pyrimidine dimers in the epidermal DNA of two strains of hairless mice; Ley RD et al.; The ultraviolet-light induction of DNA damage has been measured in the epidermis of hairless mice with the use of damage-specific endonucleases from Micrococcus luteus . The rates of induction of endonuclease-sensitive sites in HRS/J/Anl and Skh:hairless-1 mice were 6.1 +/- 0.5 X 10(-11) and 6.5 +/- 0.8 X 10(-11)/dalton/J/sq m from a FS40 fluorescent sun lamp (280 to 400 nm), respectively . Enzymatic photoreactivation with yeast photoreactivating enzyme showed that approximately 80% of the endonuclease-sensitive sites were cycloburyl pyrimidine dimers . In both strains of mice the pyrimidine dimers remained in high-molecular-weight DNA for 24 hr after irradiation . These data show that mouse epithelial cells in vivo have little or no capacity for the excision repair of pyrimidine dimers.

Mikrobiologiia, 1977 Sep-Oct, 46(5), 867 - 77
{The protective role of pigments against UV rays in fungi isolated from the mesosphere}; Lysenko SV et al.; Five among six species of microorganisms isolated from the mesosphere contained pigments which made them more resistant to the action of UV as compared to pigmentless microorganisms in the atmosphere of Earth . UV irradiation in the atmosphere is supposed to select resistant pigmented forms, so that they predominate in the mesosphere . To confirm this assumption, mutants of Aspergillus niger, Penicillium notatum and Circinella muscae were sported by irradiating them four times and then subjecting to stepwise selection . These mutants either synthesized pigments at a very low rate or did not produce them at all . No significant differences were found by studying the biomass, mycelium and sporeforming organs of the parent cultures and their mutants . However, their resistance to UV was not the same . Addition of the pigment apsergillin, isolated from the conidia of Aspergillus niger, to a suspension of the pigmentless (mutant) conidia of Penicillium notatum, the spores of Circinella muscae, and the vegetative cells of Micrococcus albus, before their irradiation with UV, considerably increased their resistance to this factor.

Cancer Res, 1977 Sep, 37(9), 3414 - 9
DNA repair in V-79 cells treated with combinations of ultraviolet radiation and N-acetoxy-2-acetylaminofluorene; Ahmed FE et al.; Earlier experiments on human cells showed that N-acetoxy-2-acetylaminofluorene mimics ultraviolet radiation in biological and repair characteristics and that the amount of repair from a combined treatment was additive . Chinese hamster V-79 cells are less proficient than human cells in excision repair of pyrimidine dimers resulting from irradiation . We therefore investigated the combined effects of both agents on repair in V-79 cells to see whether they follow the same pattern as in human cells . They did not . Measurements of unscheduled DNA synthesis and the photolysis of DNA repaired in the presence of bromodeoxyuridine gave information about repair due to both agents, and the use of an endonuclease in an extract of Micrococcus luteus allowed us to measure repair of only ultraviolet damage in the presence of N-acetoxy-2-acetylaminofluorene damage . Each technique indicated that the amount of repair from a combined treatment was less than additive and in some cases less than that due to either agent . We conclude that V-79 cells are different from human fibroblasts in the excision repair of both ultraviolet and N-acetoxy-2-acetylaminofluorene damage and suggest that both kinds of damages inhibit repair of damage due to the other agent.

Immunology, 1977 Sep, 33(3), 275 - 84
Restriction of the anti-bovine serum albumin response in rabbits immunized with Micrococcus lysodeikticus; De Baetselier P et al.; Rabbits capable of producing antibodies of restricted heterogeneity in response to Micrococcus lysodeikticus are equally capable of producing antibodies of restricted heterogeneity to bovine serum albumin . These antibodies are produced when animals are simultaneously injected with micrococcus and BSA and their specificity is restricted to a small number of epitopes . These results suggest that micrococcal vaccines can induce the restriction of heterogeneity in antibodies raised against totally unrelated antigens.

Mol Cell Biochem, 1977 Aug 19, 17(1), 17 - 23
Activation parameters and molecular changes induced by substrate hydrolysis of the adenosine triphosphatase of Micrococcus lysodeikticus . A comparison of three different soluble forms of the enzyme; Ayala J et al.; The Arrhenius plots for the active and low activity soluble forms of the ATPase purified from the membranes of Micrococcus lysodeikticus grown at 30 degrees C presented discontinuities at 30 and 33 degrees C, respectively . Their activation parameters differed, being highest for the low activity form of the enzyme . Both forms underwent changes in their molecular properties as a consequence of being enzymically active, i.e., upon incubation with substrates at an adequate temperature . These changes consisted of a decrease in the relative mobilities of some of their subunits in dodecyl sulphate polyacrylamide gel electrophoresis, and the temperature at which they occurred depended on the energy of activation of the particular form of the ATPase used . The low activity form required an incubation temperature of 50 degrees C, whereas for an active form 37 degrees C was sufficient.

Biochim Biophys Acta, 1977 Aug 2, 477(3), 288 - 94
Organization and transcriptional activity of brain chromatin subunits; Brown I et al.; Digestion of brain nuclei with micrococcal nuclease produces 11.2-S chromatin subunits which comprise up to 80% of the total nuclear DNA . Hybridization studies with excess subunit DNA demonstrate that subunits are distributed throughout the repeated and nonrepeated sequences of the genome . No class of nonrepeated DNA appears to be excluded from subunits . Transcribed DNA is present in chromatin subunits since in vitro labelled poly(A+)-mRNA hybridizes to excess subunit DNA with kinetics identical to that for total DNA.

Br J Dermatol, 1977 Aug, 97(2), 187 - 96
Evaluation of crew skin flora under conditions of a full quarantine lunar-exploration mission; Carmichael C et al.; Crew-members of the Apollo 14 lunar exploration mission underwent a pre-flight seclusion designed to stabilize their health by freeing them from exposure to potentially infectious agents . After the flight, the crew-members were quarantined to protect the biosphere from possible lunar contamination . These isolations, along with the complete isolation of the spaceflight itself, provided the opportunity for a skin flora survey which included the sampling of seven sites at five different times . Quantification and identification of all aerobic and anaerobic bacteria from each site were performed . The results indicated that the pre-flight quarantine measures resulted in a decrease in total numbers of isolates as well as a decrease in the anaerobes . This was followed by a continued decrease throughout the flight with a return to the pre-flight norm within 16 days after the flight . The quantitative load of aerobic bacteria increased during the flight, due largely to an increase in coryneforms and micrococcaceae . The quantitative load of anaerobic bacteria decreased before and during the flight . No instance of microbial shock or intercrew transfer of micro-organisms was demonstrated . These findings indicate that alterations in the skin flora do not pose any unusual problem during short duration space flights . Further, there are no indications that problems will arise on longer missions.

Nucleic Acids Res, 1977 Aug, 4(8), 2619 - 28
Nonuniform distribution of DNA repair in chromatin after treatment with methyl methanesulfonate; Bodell WJ; The distribution of methyl methanesulfonate induced DNA repair was measured in mouse mammary cell chromatin by digestion of "repair labeled" nuclei with micrococcal nuclease . The results indicate that there is a nonuniform distribution of DNA repair in chromatin . The chromatin fraction digested during the first 5 minutes of incubation with micrococcal nuclease appears to be a primary site of DNA repair after methyl methanesulfoante treatment . The observed nonuniform distribution of DNA repair in chromatin may be due to 1)a nonrandom alkylation of DNA in chromatin by methyl methanesulfonate or 2)areas in chromatin of increased accessibility for the repair enzymes to the DNA lesions.

Nucleic Acids Res, 1977 Jul, 4(7), 2169 - 80
Digestion of insect chromatin with micrococcal nuclease, DNase I and DNase I combined with single-strand specific nuclease S1; Schmidt ER; The chromatin of the lepidopteran Ephestia kuehniella was digested by micrococcal nuclease, DNase I and S1-nuclease combined with DNase I pretreatment . The resulting DNA fragments were analyzed by gel electrophoresis and compared with the DNA fragments of rat liver nuclei obtained by the same process . Extensive homology was revealed between insect and mammalian chromatin structure . The combined DNase I- S1-nuclease digestion yields double-stranded DNA fragments of lengths from 30 to 110 base-pairs . These DNA fragments are not obtained from nuclei predigested extensively with micrococcal nuclease . The results are discussed with respect to the internal structure of the chromatin subunit.

Can J Biochem, 1977 Jul, 55(7), 736 - 46
A thermal denaturation study of chromatin and nuclease-produced chromatin fragments; Lewis PN; Calf thymus chromatin and nuclease-produced chromatin fragments have been examined by thermal denaturation measurements . Native chromatin gave a series of distinct melting transitions at 64, 73,79, and 85 degrees C in 0.25 mM EDTA pH8 . Treatments such as dialysis, mechanical shearing, or sulfhydryl oxidation of histone H3 carried out on native chromatin significantly altered the derivative melting profiles by blurring the distinct transitions and shifting the highest melting transition to a lower temperature . Derivative melting profiles for electrophoretically purified chromatin fragments, monomer through hexamer, all resembled that obtained from dialyzed chromatin . These results suggest that higher order structures exist in chromatin that are easily disrupted . Since the products of micrococcal nuclease (EC3.1.4.7) digestion of the altered chromatins did not exhibit any major electrophoretic differences from those obtained from nuclei, than most likely the primary arrangements of histones along the DNA are the main determinant for cleavage sites.

J Histochem Cytochem, 1977 Jul, 25(7), 784 - 9
A high efficiency flow cytometer; Skogen-Hagenson MJ et al.; A flow chamber has been developed which collects about 60% of the total cell fluorescence for analysis compared to about 2.5% for conventional flow systems . The chamber, an ellipsoid of revolution, is gold-plated for increased reflectivity . Fluorochrome-stained cells enter the flow cell directly above the primary focus of the ellipsoid at the rate of 1000 cell/sec . A focused argon-ion laser beam enters the flow cell parallel to the semiminor axis and intersects the cell stream at the primary focus . Fluorescent light emanating from this point is reflected toward the secondary focus, where it exits the chamber for analysis . The high efficiency flow cytometer has been used to obtain nucleotide fluorescence distributions from samples of Micrococcus glutamicus bacteria stained with propidium iodide and of spermatozoa stained by the acriflavine-Feulgen procedure.

Proc Natl Acad Sci U S A, 1977 Jul, 74(7), 2810 - 4
Selective association of the trout-specific H6 protein with chromatin regions susceptible to DNase I and DNase II: possible location of HMG-T in the spacer region between core nucleosomes; Levy W B et al.; Nuclei and chromatin from trout testis cells were digested with three different nucleases (DNase I, DNase II, and micrococcal nuclease), and the acid-soluble proteins that were solubilized and those remaining bound to the nuclease-resistant DNA were compared electrophoretically . With the conditions described by H . Weintraub and M Groudine {(1976) science, 193, 848-856}, which we previously found to be selective in digesting actively transcribed regions in trout testis chromatin, a single chromosomal protein, H6, was solubilized . The nucleosomal histones and H1 remained insoluble, bound to the resistant DNA . In contrast, digestion with micrococcal nuclease led to a preferential solubilization of a second protein, HMG-T, together with the release of some nucleosomal histones and H1 into the soluble fraction . DNase II also discriminated between "active" and "inactive" chromatins; when a DNase II-solubilized "active" chromatin fraction was prepared, it too was enriched in H6 and HMG-T . Thus, both H6 and HMG-T, the two major low-salt extractable chromosomal nonhistone the two major low-salt extractable chromosomal nonhistone proteins from trout testis, are associated with chromatin regions selectively sensitive to nucleases . The preferential solubilization of HMG-T by micrococcal nuclease action suggests that it might be located at the internucleosomal "spacer" region.

Proc Natl Acad Sci U S A, 1977 Jul, 74(7), 2725 - 8
Distribution of 5-methylcytosine in chromatin; Razin A et al.; The content of 5-methylcytosine in eukaryotic DNA was measured by mass spectrometry . Almost equal amounts of methylated cytosine were found in the DNA of various tissues of the chicken . When chromatin or nuclei were digested with micrococcal nuclease, 50% of the DNA was found to be nuclease resistant . In contrast to this, over 75% of the 5-methylcytosine was protected from nuclease digestion by chromatin proteins . These results suggest that 5-methylcytosine is nonrandomly distributed with respect to the nucleoproteins.

Biokhimiia, 1977 Jul, 42(7), 1173 - 83
{Analysis of the activity of Micrococcus luteus endonucleases with respect to gamma-irradiated DNA}; Tomilin NV et al.; Endonucleases from Micrococcus luteus that induce single-strand breaks in gamma-irradiated DNA have been separated chromatographycally into two groups . The first group involves two different enzymes: AP-endonuclease II (mol . weight 30 000) and AP, UV-endonuclease I (mol . weight 15 000) that recognize alkali-labile lesions in gamma-irradiated DNA and apurinic sites in DNA heated at 70 degrees C, pH 6.08 AP-endonuclease II in cooperation with DNA polymerase from M . luteus and T4 phage-induced polynucleotide ligase is capable of carrying out in vitro complete excision repair of alkali-labile lesins in gamma-irradiated DNA . The second group involves gamma-endonucleases X and Y that act on alkalistable gamma-ray lesions . gamma-endonucleases X and Y can be separated by chromatography on DEAE-cellulose but possess similar properties . Activity of gamma-endonucleases toward gamma-irradiated DNA is inhibited by only heavily UV-irradiated DNA (15 000 ergs/mm2) . The data are consistent with the hypothesis that gamma-endonucleases are specific for thymine glycols (t' and tUV) in UV- and gamma-irradiated DNA.

Eur J Biochem, 1977 Jun 15, 76(2), 355 - 63
Binding of polylysine to chromatin subunits and cleavage by micrococcal nuclease . A comparison of accessible sites; Doenecke D; Native chromatin and chromatin subunits (nucleosomes) were titrated with polylysine and digested with micrococcal nuclease and deoxyribonuclease I at individual lysine/nucleotide ratios . In contrast to earlier reports, which had been obtained using mechanically sheared chromatin, a comparison of the sites accessible for micrococcal nuclease and polylysine reveals that polylysine does not preferentially protect the micrococcal-nuclease-susceptible sites in chromatin . Similar results were obtained in digestion experiments with DNase I . From the experimental data presented we conclude that polylysine does not preferentially bind to the internucleosomal DNA, which is the prime target site for micrococcal nuclease, but rather to the total nucleosomal DNA moiety.

Nucleic Acids Res, 1977 Jun, 4(6), 2039 - 55
Chromatin core particle unfolding induced by tryptic cleavage of histones; Lilley DM et al.; Chromatin 'core particles' have been digested with trypsin to varying extents . The resulting particles are homogeneous by the criterion of ultracentrifuge boundary analysis . Sedimentation coefficients are lowered as cleavages are introduced into the histones, showing that an unfolding of the core particle occurs . This unfolding is further characterised by a lower melting temperature together with a premelting phase, higher molar ellipticity in the circular dichroism spectra at 280 nm and increased kinetics of digestion by both micrococcal nuclease and DNase I . Differences are also observed in the products of nuclease digestion . The most consistent interpretation of the data involves an unfolding process whereby free rods of DNA are released to extend from a nucleoprotein core.

Biokhimiia, 1977 Jun, 42(6), 985 - 93
{Isolation and properties of Micrococcus luteus endonucleas acting in DNA depurinization but inactive with pyrimidine dimers}; Tomilin NV et al.; An endonuclease (AP-endonuclease II) that specifically attacks double stranded or single stranded depurinated DNA, resulting in single-strand nicks, has been purified 320-fold from Micrococcus luteus . The enzyme is not stimulated by 0.002 M MgCl2, it induces 3'OH-5'PO4 breaks on the 5' side of apurinic sites, it has no activity towards UV-irradiated DNA and has a molecular weight of about 30 000 . In cooperation with DNA-polymerase from M . luteus and T4 DNA ligase, AP-endonuclease II has been shown capable of carrying out complete excision repair of depurinated DNA in vitro.

Infect Immun, 1977 Jun, 16(3), 974 - 82
Role of lysozyme in the microbicidal activity of rat alveolar macrophages; Biggar WD et al.; Lysozyme release from alveolar macrophages is stimulated by exposure to particles, such as latex and zymosan, and to bacteria . Rat alveolar marcophages contain 10-fold-greater intracellualr concentrations of lysozyme and release more lysozyme after stimulation than rat blood neutrophils . During 30 min of incubation in vitro, alveolar macrophages kill more than 99% of Micrococcus lysodeikticus in the incubation mixture, whereas neutrophils kill approximately 50% of the bacteria . The bactericidal capacity of alveolar macrophages for M . lysodeikticus exceeds that of neutrophils at all bacteria-to-cell ratios tested . This bacterial killing by alveolar macrophages is inhibited when specific rabbit antirat lysozyme serum is added to the incubation mixture . Electron microscopy studies indicate that bacterial killing occurs extracellularly . Initial degradation of bacteria occurs within 5 min, and lysis is complete by 25 to 30 min . Phagocytosis of lysed bacteria is maximum after 25 to 30 min . The greater quantities of lysozyme, both intracellularly and released into the extracellular environment by alveolar macrophages, suggest that this factor may be a mechanism by which alveolar macrophages contribute to pulmonary defense.

Clin Chem, 1977 Jun, 23(6), 967 - 70
Immunochemical determination of human lysozyme by laser nephelometry; Goudswaard J et al.; The methods currently available for quantitative determination of lysozyme are based on the capacity of the enzyme to lyse Micrococcus lysodeikticus . Previous attempts to develop immunochemical assays have been reported, but the sensitivity was inferior to that of the most widely used lysoplate method . We describe the development of a sensitive immunochemical method for lysozyme assay in which the recently developed laser nephelometer is used . The sensitivity so achieved is at least comparable to that of the lysoplate method, and in some circumstances better . Results obtained by the lysoplate assay and the nephelometric assay correlate well . Among the advantages of our method are easier handling of larger numbers of samples, quicker results, and the possibility of assaying enzymatically inactive forms of the enzyme.

Br J Dermatol, 1977 Jun, 96(6), 623 - 6
Acne vulgaris: an investigation into the number of anaerobic diphtheroids and members of the Micrococcaceae in normal and acne skin; Holland KT et al.; A quantitative study was made of the microflora of 174 acne and 68 non-acne subjects . Two groups of organisms were investigated, the anaerobic diphtheroids and members of the Micrococcaceae . The results showed high numbers of both groups of bacteria in skin bearing blackheads, papules or pustules and in non-acne adolescent skin . There were significantly lower numbers of bacteria in the pilosebaceous ducts of normal looking skin in acne areas and in pre-adolescent skin when compared with non-acne adolescent skin . It is suggested that increased numbers of bacteria alone do not predispose to acne, but that their interaction with the skin, which is a function of the localized skin environment, may be important.

J Biol Chem, 1977 May 25, 252(10), 3460 - 5
Initial reactions in biosynthesis of teichuronic acid of Micrococcus lysodeikticus cell walls; Rohr TE et al.; The in vitro biosynthesis of teichuronic acid, the cell wall polysaccharide of Micrococcus lysodeikticus, occurs in two stages . In the initial stage, the particulate enzyme fraction utilizes uridine diphosphate N-acetylglucosamine (UDP-GlcNAc) and uridine diphosphate N-acetylmannosaminuronic acid (UDP-ManNAcUA) to form three intermediates . N-Acetylglucosamine is transferred from UDP-GlcNAc to a carrier lipid present in the particulate enzyme fraction to form the first intermediate, GlcNAc carrier lipid . N-Acetylmannosaminuronic acid is then transferred from UDP-ManNAcUA to the GlcNAc carrier lipid to form ManNAcUA-GlcNAc carrier lipid, the second intermediate . Finally, the transfer of an additional N-acetylmannosaminuronic acid residue from UDP-ManNAcUA yields the third intermediate, (ManNAcUA)2-GlcNAc carrier lipid . Reactions involving UDP-ManNAcUA release uridine diphosphate . Concomitant synthesis of peptidoglycan or membrane mannan inhibits the synthesis of the teichuronic acid intermediates, thereby providing indirect evidence that the carrier lipid is undecaprenol monophosphate.

Biochemistry, 1977 May 17, 16(10), 2231 - 5
L cell DNA ligase joins RNA to DNA on a DNA template; Bedows E et al.; L cell DNA ligase catalyzes a covalent linkage between 5'-hosphoryl oligodeoxyribonucleotides and 3'-hydroxyl oligoribonucleotides on a complementary polydeoxyribonucleotide template . This reaction occurs to a substantially lesser extent than does the sealing of DNA to DNA . The joining of {5'32P}d(pA)12-18 to (Ap)11A on poly{d(T)} or of {5'-32P}d(pG)12-18 to 5'-hydroxyl, 3'-hydroxyl oligo(I) ON POLY{D(C)} was demonstrated by the formation of alkaline phosphatase resistant radioactivity . The 32P of the hybrid reaction products became sensitive to the action of alkaline phosphatase after treatment with alkali . Furthermore, hydrolysis of the products of the linkage of {5'-32P}d(pG)12-18 to 5'-hydroxyl, 3'-hydroxyl oligo(I) on poly{d(C)} with micrococcal nuclease and spleen phosphodiesterase resulted in the formation of {3'-32P}IMP . Attempts to seal {5'-32p{-(pA)12 to d(Ap)11-17A on poly{d(T) or {5'-32P}oligo(pI) to d(Gp)11-17G on poly{d(C)} were unsuccessful.

Arch Microbiol, 1977 May 13, 113(1-2), 39 - 42
The photosensitivity of the malate oxidase system of a pigmented strain and a carotenoidless mutant of Sarcina lutea (Micrococcus luteus); Prebble J et al.; The effect of white light on the malate oxidase of Sarcina lutea (Micrococcus luteus) membranes has been examined using a carotenoid-containing and a carotenoidless mutant . At least three photosensitive sites have been detected . Two of these are associated with the malate dehydrogenase complex (malate-menaquinone reductase) and are unaffected by membrane carotenoid . A third site which has been detected beyond the dehydrogenase complex, is protected by carotenoid since it can only be demonstrated in carotenoidless systems . A repair mechanism has been found for one of the two sites in the dehydrogenase complex.

Biochim Biophys Acta, 1977 May 2, 466(3), 451 - 60
Phosphate transport in Micrococcus lysodeikticus; Friedberg I; Phosphate accumulates in Micrococcus lysodeikticus cells against a concentration gradient, by an energy-dependent process . The phosphate transport is derepressed during phosphate deprivation . The depression process is inhibited by chloramphenicol . The apparent Km of phosphate transport is 4.3 micronM . The activation energy of the transport is 21 kcal per mol in the temperature range of 0-29degrees C, and 4.9 kcal per mol between 29 and 40degrees C . The rate of the transport increases in presence of K+ and Mg2+ . Arsenate is a competitive inhibitor of phosphate transport, having an apparent Ki of 6.0 micronM . Sulfhydryl reagents, respiratory inhibitors and uncouplers of oxidative phosphorylation inhibit phosphate transport.

J Biochem (Tokyo), 1977 May, 81(5), 1181 - 6
The structure of the branching point between acidic polysaccharide and peptidoglycan in Micrococcus lysodeikticus cell wall; Hase S et al.; An acidic polysaccharide fraction composed of glucose and N-acetylmannosaminuronic acid with a small portion of peptidoglycan was isolated by enzymic digestion and subsequent ECTEOLA-cellulose chromatography from the cell walls of Micrococcus lysodeikticus . On mild acid treatment, the fraction became Morgan-Elson positive and formed the Morgan-Elson chromogen on heating with phosphate buffer (pH 7) . The product of mild acid treatment released inorganic phosphate on treatment with phosphomonoesterase . After gel-chromatography on Sephadex G-25 and DE-32, the acidic polysaccharide fraction contained less glucosamine than muramic acid . By reduction of this fraction with borohydride, a part of the glucosamine was converted into glucosaminitol . Based on these results, it is suggested that the acidic polysaccharide is linked to glucosamine by a (1-3) linkage, which is linked to the 6 position of a muramic acid residue by a phosphodiester linkage.

Appl Environ Microbiol, 1977 May, 33(5), 1129 - 33
Minimal requirements in defined media for improved growth of some radio-resistant pink tetracocci; Shapiro A et al.; Defined media permitting extensive growth of representative pink radio-resistant tetracocci (Micrococcus radiodurans, Micrococcus roseus, and Micrococcus radiophilus) and two controls (an ultraviolet-sensitive mutant of M . radiodurans and Micrococcus luteus) are described . Availability of Fe (especially Fe3+) proved essential for good growth, as evidenced by (i) favorable effects of hydroxamic acids, e.g., salicylhydroxamic acid, and (ii) the growth promotion by hemin when joined with elevated concentrations of Fe . Cobalamin (B12) and methionine were interchangeable as an absolute requirement for methionine not affected by B12 . M . luteus required neither . Pink radio-resistant micrococci may form a coherent group . Some divergences among them might be attributable to the method for isolating them, which for ordinary bacteria would be mutagenic to the point of total lethality . The ecology of these tetracocci vis-a-vis other pink-red radio-resistant organisms is discussed in relation to a question: can these bacteria be isolated without dependence on radiation as the cardinal selective factor?

J Gen Microbiol, 1977 May, 100(1), 43 - 8
A radioresistant Gram-positive asporogenous rod isolated from the faeces of a giant panda (Ailuropoda melanoleuca); Kobatake M et al.; A highly radioresistant bacterium was isolated from the faeces of a giant panda (Ailuropoda melanoleuca) . When the organism was subjected to gamma irradiation in phosphate buffer, the induction dose and D10 values were 846 and 345 krad, respectively, for cells grown on PCNZ agar, and 700 and 460 krad, respectively, for the enlarged cells grown on 5% (v/v) horse blood brain heart infusion agar . The D10 value of the former cells was about 1.8 times higher than that of Micrococcus radiodurans grown on PCNZ agar.

Prikl Biokhim Mikrobiol, 1977 May-Jun, 13(3), 365 - 70
{Non-ionogenic detergents with antibacterial activity and their effect on bacterial membrane systems}; Kofkina EP et al.; Certain new nonionogenic detergents which are hydroxy-polyethoxy-derivatives of dodecane show in vitro bacteriostatic action as related to gram-positive microorganisms . In this respect they are not inferior to chloride cetylpyridinium or sodium dodecyl sulphate . They are similar to chloride cetylpyridinium in their ability to disrupt the osmotic barrier of protoplasts and to inhibit NAD-H-oxidase of membrane fractions of Micrococcus lysodeikticus . Unlike chloride cetylpyridinium and sodium dodecyl sulphate, nonionogenic detergents do not inhibit membrane-bound ATPase of these bacteria.

Biotechnol Bioeng, 1977 May, 19(5), 631 - 48
The enzymatic conversion of L-histidine to urocanic acid by whole cells of Micrococcus luteus immobilized on carbodiimide activated carboxymethylcellulose; Jack TR et al.; Whole cells of Micrococcus luteus (formerly Sarcina lutea ATCC 9341) have been covalently linked to a carboxymethylcellulose support system, with the retention of histidine ammonia-lyase activity . The dependence of the rate of urocanic acid formation on pH, temperature, and added surfactant concentration was similar for the free and the immobilized cells . The immobilization procedure used is based on the carbodiimide activation of carboxymethylcellulose and has been optimized for the histidine ammonia-lyase activity of the immobilized cells on a given weight of cellulose . In a column reactor at 23 degrees C and superficial velocity of 0.044 cm/min, 5 g of cellulose with bound cells gave a 35% conversion of an L-histidine solution (0.25M, pH 9.0) to urocanic acid for 16 days of continuous operation . The scope of this carbodiimide assisted immobilization procedure has been investigated for a series of microorganisms and a variety of carboxylate functionalized supports.

Biochemistry, 1977 Apr 19, 16(8), 1690 - 5
Fractionation of purified nucleosomes on the basis of aggregation properties; Sanders MM et al.; Monomeric nucleosomes from micrococcal nuclease digest of rat liver nuclei have been purified on Sepharose columns in the presence of divalent cations and 0.6 M NaCl . The particles contain histones H2A, H2B, H3, H4, and a complement of nonhistone chromosomal proteins . In 0.6 M NaCl, the nucleosome mixture sedimented at 10 S; however, when the NaCl was removed approximately 30% of the particles aggregated and precipitated, and the remaining soluble fraction sedimented at 11 S . The aggregation phenomenon was divalent cation-dependent and reversible . Characterization of the macromolecular components of the subfractions of nucleosomes showed that the subfractions differed in composition of species of histone H3 as well as of several nonhistone chromosomal proteins but not in the size of the DNA fragment present . The aggregation properties of the isolated nucleosomes showed similarities to the divalent cation-dependent differences in the extent of chromatin condensation in the intact eukaryote nucleus.

Cell, 1977 Apr, 10(4), 633 - 40
Variation in chromatin structure in two cell types from the same tissue: a short DNA repeat length in cerebral cortex neurons; Thomas JO et al.; We have used micrococcal nuclease as a probe of the repeating structure of chromatin in four nuclear populations from three tissues of the rabbit . Neuronal nuclei isolated from the cerebral cortex contain about 160 base pairs of DNA in the chromatin repeat unit, as compared with about 200 base pairs for nonastrocytic glial cell nuclei from the same tissue, neuronal nuclei from the cerebellum and liver nuclei . All four types of nuclei show the same features of nucleosomal organization as other eucaryotic nuclei so far studied: nucleosomes liberated by digestion with micrococcal nuclease give a "core particle" containing 140 base pairs as a metastable intermediate on further digestion and a series of single-strand DNA fragments which are mutiples of 10 bases after digestion with DNAase I . Nuclei from cerebral cortex neurons, which have a short repeat, are distinct from the others in being larger, in having a higher proportion of euchromatin (dispersed chromatin) as judged by microscopy and in being more active in RNA synthesis in vitro.

Proc Natl Acad Sci U S A, 1977 Apr, 74(4), 1548 - 52
Different rate-limiting steps in excision repair of ultraviolet- and N-acetoxy-2-acetylaminofluorene-damaged DNA in normal human fibroblasts; Ahmed FE et al.; In normal human cells the amount of excision of ultraviolet damage to DNA saturates at high doses . In these cells some chemicals mimic ultraviolet damage as far as their biological and repair characteristics are concerned . One of these chemicals is N-acetoxy-2-acetylaminofluorene . We determined whether the limited repair capacity for ultraviolet damage was affected by treatment with N-acetoxy-2-acetylaminofluorene . To measure repair we determined unscheduled DNA synthesis and the number of sites sensitive to an ultraviolet endonuclease in an assay using an extract of Micrococcus luteus . The nuclease does not act on DNA treated with the chemical . The amount of unscheduled DNA synthesis due to a combined chemical and ultraviolet treatment was the sum of those observed from the separate treatments, even at saturation doses . The combined treatment did not affect the removal of nuclease-sensitive sites . We conclude that there are different rate-limiting steps in excision repair of the ultraviolet and the chemical damage and suggest a model involving a complex of enzymes to explain the data.

Acta Pathol Microbiol Scand {B}, 1977 Apr, 85(2), 174 - 6
The testing of the antibiotic sensitivity of bacteria on an agar medium: The problem of a double zone of inhibition; Korkela H et al.; When the sensitivity of Micrococcus luteus ATTC9341 to streptomycin, erythromycin, oleandomycin and spiramycin was tested by an agar diffusion method using antibiotic impregnated filter paper disks on unbuffered Penassay Seed Agar two zones of inhibition were observed around the disks after an incubation period of 24 hours at 30 degrees C . The pH of the M . luteus seeded Penassay Seed Agar was measured before and after 24 hours incubation at 30 degrees C and found to be 6.6 and 8.7, respectively . When the Penassay Seed Agar was buffered to pH 6.1 and the sensitivity of the microbe to the antibiotics was tested as before no double zones of inhibition could be observed . The phenomenon of the double zones of inhibition may possibly be due to the pH increase of the medium from a relatively low level to the optimum range of activities of the antibiotics during the incubation period.

Biochim Biophys Acta, 1977 Mar 18, 475(2), 241 - 53
Preparation and enzymatic hydrolysis of dinucleoside monophosphates and DNA modified with aromatic residues; Brown HS et al.; The following procedures have been used to prepare fifteen modified dinucleoside monophosphates: (a) bisulfite-catalyzed transamination with aniline to give an N4-phenylcytidine (CPh), (b) bisulfite-catalyzed transamination with beta-naphthylamine to give an N4-beta-naphthylcytidine (CbetaN), (c) alkylation with 7-bromomethylbenz{a} anthracene to afford a 7(benz{a}anthryl-7-methyl)guanosine (GMBA), and (d) reaction with N-acetoxy-2-acetylaminofluorene to give an 8-(N-2-fluorenylacetamido)guanosine (GAAF) . The compounds prepared were A-CPh, CPh-A, CPh-G, U-CPh, CPh-U, A-CbetaN, CbetaN-A, G-CbetaN, CbetaN-G, U-CbetaN, CbetaN-U, GMBA-U, U-GMBA, GAAF-U, and U-GAAF . All of the modified compounds were hydrolyzed to the expected monomers with venom and spleen exonucleases . Hydrolysis by micrococcal nuclease was inhibited in the following cases: A-CPh, A-CbetaN, U-GMBA, and U-GAAF . The first three reactions above were applied to denatured calf thymus DNA to prepare modified DNA samples containing from 0.3 to 2.0% bound aromatic residues . The modified nucleic acids were completely hydrolyzed to nucleosides by the combination of venom exonuclease, deoxyribonuclease I and alkaline phosphatase . The same results were obtained with a combination of spleen exonuclease, deoxyribonuclease II, and alkaline phosphatase . Hydrolysis of the modified nucleic acids by micrococcal nuclease and alkaline phosphatase afforded primarily nucleosides, with some dinucleoside monophosphates . The amount of the latter did not exceed that found in the hydrolysis of control DNA, however . Other workers have observed inhibition of enzymatic hydrolysis of nucleic acids modified by aromatic carcinogens . We postulated that their results may have been caused by cross-links, which were avoided in our studies.

Biochemistry, 1977 Mar 8, 16(5), 925 - 32
The photoaddition of trimethylpsoralen to Drosophila melanogaster nuclei: a probe for chromatin substructure; Wieshahn GP et al.; Derivatives of the furocoumarin, psoralen, can penetrate intact cells or nuclei and cross-link opposite strands of the chromosomal DNA under the influence of long wave-length ultraviolet light . The potential of trioxsalen (4,5',8-trimethylpsoralen) as a probe for chromatin structure has been investigated . The DNA in both embryo nuclei and tissue culture cells from Drosophila melanogaster was found to be about 90% protected from trioxsalen binding relative to purified DNA . Digestion of trioxsalen-treated nuclei by micrococcal nuclease and gel electrophoresis of the resulting DNA gave the same type of band pattern that is characteristic of native, untreated nuclei are digestion . Nuclease digestion was therefore used to examine the distribution of bound trioxsalen in the DNA . The resulting DNA fragments were analyzed both by radioactivity measurements and quantitative electron microscopy . The nuclease cleaved intact photoreacted nuclei in such a way that preferential excision of trioxsalen containing regions of the DNA occurred, but, when acting upon purified DNA that contained bount trioxsalen, it attacked the trioxsalen-free regions preferentially . It was thus concluded that trixosalen binds at the sites corresponding to the regular nuclease-sensitive regions of the chromatin in nuclei.

Biochim Biophys Acta, 1977 Mar 2, 475(1), 139 - 51
Developmental study of the structure of sea urchin embryo and sperm chromatin using micrococcal nuclease; Keichline LD et al.; Sea urchin embryo chromatin is hydrolyzed by micrococcal nuclease into a series of oligomers which are multiples of a monomer (repeating unit) containing 220 +/- 22 nucleotide pairs of DNA which accumulates during the initial phase of the digestion . Although the size of the chromatin monomers remains the same throughout early development, from the morula through the pluteus stage of embryogenesis, the rate and extent of solubilization of chromatin DNA by micrococcal nuclease decrease as development proceeds . Sea urchin spermchromatin is hydrolyzed by micrococcal nuclease into a series of oligomes which are multiples of a monomer containing 260 +/- 26 nucleotide pairs of DNA which accumulates during the initial phase of the digestion . Analysis of the sizes of oligomers which result form micrococcal nuclease digestion of mouse liver, sea urchin embryo, and sea urchin sperm chromatin in situ, suggests that the oligomers are nearly exact multiples of the respective monomers . These results are discussed in relation to those studies which have shown that the histone complement of the sea urchin embryo and sperm changes during development.

Biochim Biophys Acta, 1977 Mar 2, 475(1), 131 - 8
Nucleoprotein chromatin subunit from Physarum polycephalum; Staron K et al.; The nucleoproteins resulting from digestion of the nuclei of the true slime mold Pysarum polycephalum with micrococcal nuclease have been resolved according to the size classes in linear sucrose gradients containg 0.5 M NaCl, and analysed for DNA, RNA and protein content . The basic nucleoprotein subunit has been found to contain a DNA fragment of about 150--170 base pairs complexed with an approximately equal amount, on a weight basis, of basic proteins and a relatively small amount of non-histone proteins (about 35% of the amount of DNA) . Higher nucleoprotein oligomers were shown to contain spacer DNA fragments between adjacent subunits and a considerably higher ratio of non-histone proteins to DNA than the basic subunit . Both the basic subunit and higher nucleoprotein oligomers of Physarum chromatin contain some amount of tightly bound RNA . However, in contrast to the distribution of the non-histone proteins, the ratio of RNA to RNA is similar in both fractions.

Biochim Biophys Acta, 1977 Mar 2, 475(1), 23 - 31
Separation of DNA-dependent DNA polymerase activities in Micrococcus radiodurans; Kitayama S et al.; DNA polymerase activities in Micrococcus radiodurans were separated into two fractions after purification more than 2000 fold . They differ in pH optimum and residual activities in the absence of a full deoxyribonucleoside triphosphates complement . NAD partly inhibited one of the activities . Both activities were eluted as a single peak on gel filtration and sedimented at the same rate on glycerol gradient centrifugation . Molecular weight 140000 was calculated from Stokes radius and sedimentation constant . Deoxyribonuclease activity was detected on one of the polymerase activities which preferentially degraded double-stranded DNA . Priming activity of nicked DNA was reduced by gamma-irradiation . These results have been related to the possible rolls in repair synthesis in vivo or DNA synthesis in permeable cells of M . radiodurans.

Am J Gastroenterol, 1977 Mar, 67(3), 245 - 8
Serum lysozyme levels in inflammatory bowel disease; Manier JW et al.; Serum lysozyme levels were compared in patients with Crohn's disease (CD) and chronic ulcerative colitis (CUC) to determine if the two diseases could be differentiated by this parameter . The lysozyme concentrations were measured by three different methods: 1 . the turbidimetric clearance of Micrococcus lysodeikticus utilizing egg white lysozyme as a standard; 2 . the lysoplate assay of Osserman and Lawlor using a human lysozyme standard obtained from Dr . Osserman and 3 . the lysoplate assay obtained as a commercial kit using human lysozyme as a standard . A series of 19 CD and 23 CUC patients were compared . Contrary to the report of Falchuk, et al, the serum lysozyme levels by any of the three methods were not statistically significantly different in the two diseases . The serum levels of those with severe, moderate, or inactive disease were also not significant for CD or CUC nor in serially followed patients did levels always correspont to changes in clinical course.

J Bacteriol, 1977 Mar, 129(3), 1513 - 7
Interconversion of large packets and small groups of cells of Micrococcus rubens: dependence upon magnesium and phosphate; Yamada M et al.; Micrococcus rubens, a gram-positive occus, usually forms large, cubic packets of more than 500 cells that are regularly arranged in three-dimensional cell groups . In medium with extremely low concentration of Mg2+ and phosphate, in which the cells can only grow on a agar surface, it formed small groups of 2 to 20 cells . Irregularly arraged cell groups of intermediated size were obtained in culture media containing intermediated concentrations of Mg2+ and phosphate . Mutants that formed irregular cell groups of intermediate size under normal culture conditions were also obtained.

J Bacteriol, 1977 Mar, 129(3), 1415 - 23
Deoxyribonucleic acid repair in vitro by extracts of Escherichia coli; Masker WE; Deoxyribonucleic acid (DNA) from bacteriophage T7 has been used to monitor the capacity of gently lysed extracts of Escherichia coli to perform repair resynthesis after ultraviolet (UV) irradiation . Purified DNA damaged by up to 100 J of UV radiation per m2 was treated with an endonuclease from Micrococcus luteus that introduces single-strand breaks in irradiated DNA . This DNA was then used as a substrate to study repair resynthesis by extracts of E . coli . It was found that incubation with the extract and exogenous nucleoside triphosphates under suitable assay conditions resulted in removal of all pyrimidine dimers and restoration of the substrate DNA to its original molecular weight . Repair resynthesis, detected as nonconservative, UV-stimulated DNA synthesis, was directly proportional tothe number of pyrimidine dimers introduced by radiation . The repair mode described here appears to require DNA polymerase I since it does no occur at the restrictive temperature in polA12 mutants, which contain a thermolabile polymerase . The addition of purified DNA polymerase I to extracts made from a polA mutant restores the ability to complete repair at the restrictive temperature.

Lab Invest, 1977 Mar, 36(3), 321 - 8
The functional capacity of guinea pig megakaryocytes . II . The uptake of particles and macromolecules and the effect of rabbit antiguinea pig platelet antiserum; Fedorko ME; The capacity of megakaryocytes to take up particles and macromolecules was tested by exposing them to homologous erythrocytes, latex particles, Micrococcus lysodeikticus, and horseradish peroxidase . Uptake of particles 1.1 to 7 mum . in size was extensive under the experimental conditions employed . After uptake of each of the three particles the addition of tannic acid and calcium to the fixative produced electron-dense deposits within the vacuole surrounding the particle; therefore, the vacuole was not closed off . This finding indicates that many of the particles could be actually trapped within the preformed elements of the demarcating membrane system . Horseradish peroxidase was concentrated within cytoplasmic vacuoles after 2 hours of exposure to 0.1 mg . per ml . The presence of surface membrane receptors was determined by the sheep cell rosette method . The presence of the C3b receptor for complement was determined by the sheep cell rosette method . The presence of the C3b receptor for complement produced rosette formation . The functional capacity of megakaryocytes to react like platelets was also tested by observing cell lytic changes and determining that there was approximately 40% release of 3H-serotonin produced by specific rabbit antiguinea pig platelet antiserum in the presence of complement . These studies demonstrate several functional capacities of megakaryocytes: the uptake of particles, pinocytosis, and the cell lytic response to specific antibody.

Int J Radiat Biol Relat Stud Phys Chem Med, 1977 Mar, 31(3), 227 - 35
Endonuclease activities in extracts of Micrococcus luteus that act on gemma-irradiated DNA; Schon-Bopp A et al.; Several protein fractions containing endonuclease activity against gemma-irradiated DNA (gamma-endonuclease) were isolated from M . luteus . The crude extract was eluted on a phosphocellulose column and chromatographed on TEAE cellulose and subsequently on hydroxyapatite . Five peaks of gamma-endonuclease were obtained from each preparation . Repeated experiments showed comparable chromatographic behavior of the fractions . There was no detectable activity of U.V.-endonuclease in the fractions with gamma-endonuclease but a small contamination of endonuclease against unirradiated DNA and against DNA with apurinic sites . The gamma-endonuclease is stimulated by, but is not dependent on, magnesium . Several tests for endonuclease activity have been used: the analysis of strand breaks in calf-thymus DNA or in PM2 DNA, and the determination of end-groups formed by endonuclease, either 3'OH end-groups or phosphomonoester end groups . From the results obtained it can be assumed that the strand breaks induced by the gamma-endonuclease carry 3'OH and 5' phosphate end groups.

Biochemistry, 1977 Feb 8, 16(3), 506 - 13
Poly(adenosine diphosphate-ribose) polymerase: the distribution of a chromosome-associated enzyme within the chromatin substructure; Mullins DW Jr et al.; The distribution of a chromatin-bound, nuclear protein modifying enzyme, poly (adenosine diphosphate-ribose) polymerase, and its product, poly(ADP-ribose), among various fractions of sheared and nuclease-digested HeLa cell chromatin has been examined . Epichlorohydrin-tris(hydroxymethyl)aminomethane-cellulose and glycerol gradient fractionation of solubilized chromatin indicated that poly(ADP-ribose)polymerase activity was associated primarily with the template active regions (euchromatin), whereas the transcriptionally inert chromatin fractions were found to contain relatively low levels of ADP-ribosylating activity . When isolated HeLa cell nuclei were digested in situ with micrococcal nuclease and the resultant chromatin was fractionated into nucleosome monomers (v bodies) and oligomers by sucrose gradient centrifugation, only material sedimenting faster than the 11S monomers was found to contain appreciable poly(ADP-ribose) polymerase activity . If, on the other hand, isolated HeLa cell nuclei were first incubated with labeled NAD, the substrate for poly(ADP-ribose) polymerase, prior to the preparation and fractionation of nuclease-digested chromatin, it was found that those chromatin fractions which possess significant poly(ADP-ribose) polymerase activity (nucleosome oligomers) are relatively deficient in the labeled product of this enzyme, and that a considerable portion of the homopolymeric product is ultimately associated with the 11S v bodies . Additional evidence is presented which indicates that the absence of nucleosome monomer-associated poly(ADP-ribose) polymerase activity is not due to the absence of a suitable acceptor on these structures, and that the activity of this enzyme within the chromatin is most probably dependent upon the physical integrity of the oligomeric structures themselves.

Acta Pathol Microbiol Scand {C}, 1977 Feb, 85(1), 17 - 20
A simple procedure for determination of bacteriolytic activity in biological fluids; Bratlid D; A new procedure for spectrophotometric determination of bacteriolytic activity in biological fluids is described . The method uses Micrococcus lysodeikticus cells as substrate . By inactivation of the sample through pre-incubation in ice-water, a large number of samples can be prepared and analysed simultaneously . The necessity of performing the whole analysis in the photometer for one sample at the time is thus eliminated . By measuring the increase in transmission at 570 nm after incubation of the samples at 37 degrees C a relatively long reaction time and wide concentration range is obtained . This makes the results quite precise and reproducible . The method has been used to determine the bacteriolytic activity in serum of healthy adults . Men have significantly higher levels than women.

Cell, 1977 Feb, 10(2), 237 - 43
Assembly of SV40 chromatin in a cell-free system from Xenopus eggs; Laskey RA et al.; A cell-free system is described which assembles chromatin from purified DNA in 1 hr under physiological incubation conditions . It consists of a 145,000 x g (maximum) supernatant fraction from eggs of Xenopus laevis . It converts SV40 DNA to a nucleoprotein which co-sediments with naturally occurring SV40 chromatin and which can be cleaved by micrococcal nuclease to a highly ordered pattern of DNA fragments resembling those from digestion of liver chromatin . It inserts superhelical turns into relaxed, covalently closed DNA . The assembly process is not cooperative . Under limiting conditions, each DNA molecule becomes partially assembled . Assembly does not require replication of the DNA or protein synthesis, but occurs from a stored histone pool of at least 40 ng per egg . Under conditions of DNA excess, assembly becomes dependent upon the amount of exogenous histones added to the incubation . Apart from histones and a nicking-closing activity, chromatin assembly requires an additonal thermolabile factor which is present in the egg supernatant.

Biochem J, 1977 Feb 1, 161(2), 321 - 31
Optical properties and denaturation by guanidinium chloride and urea of the adenosine triphosphatase of Micrococcus lysodeikticus . A comparison of four molecular forms of the enzyme; Nieto M et al.; 1 . The fluorescence and circular dichroism of four homogeneous preparations of ATPase (adenosine triphosphatase) from Micrococcus lysodeikticus differing in molecular structure and enzymic properties were examined at pH 7.5 and 25 degrees . Emission was maximum at 325 and 335 nm and the relative intensities at these wavelengths may be used to characterize the different ATPase preparations . The circular-dichroism spectra exhibited negative extrema at 208 and 220 nm, and the relative value of the molar ellipticity at these wavelengths was also different for each molecular form of the enzyme . 2 . The four preparations undergo two consecutive major unfolding transitions in guanidinium chloride (midpoints at 0.94 and 1.5 M denaturant), with concomitant destruction of the quaternary structure of the protein . A comparatively minor alteration in the ATPase structure also occurred in 0.05-0.2M-guanidine and led to complete inactivation of the enzyme . The inactivation and the first unfolding transition were reversible by dilution of the denaturant; the transition with midpoint at 1.5M-guanidine was irreversible . 3 . Similar results were obtained in urea, except that the successive transitions had midpoints at concentrations of denaturant of 0.4, 2.0 and 4.5M . Low concentrations of urea caused a noticeable activation of the enzyme activity and alterations of the electrophoretic mobility of the ATPase . 4 . A model is proposed in which one of the major subunits, alpha, is first dissociated and unfolded reversibly by the denaturants, followed by the irreversible unfolding and dissociation of the other major subunit, beta, from subunit delta and/or the components of relative mobility 1.0 in dodecyl sulphate/polyacrylamide-gel electrophoresis (rho).

Biokhimiia, 1977 Feb, 42(2), 329 - 37
{Membranes of bacteria and mechanism of action of the antibiotic gramicidin S}; Kaprel'iants AS et al.; The cyclopeptide antibiotic gramicidin S taken at a concentration of 100--200 mkg/mg membrane protein rapidly increases the permeability of M . lysodeikticus protoplast membranes for substrates of respiratory chain and exogenous cytochromes c . Prolonged incubation of gramicidin S with protoplasts results in their lysis which is more fast at low temperatures . In contrast to natural gramicidin, a derivative of gramicidin S with acetylated amino groups does not inhibit either the micrococcus membrane dehydrogenase or the whole of respiratory chain and does not affect the osmotic barrier of protoplasts . Aliphatic diamines (at concentrations up to 0.1 M) and Ca2+ ions (10(-2) M) do not affect the functioning of the respiratory chain in isolated micrococcus membranes . Another derivative of the antibiotic with an increased distance of loaded amino groups from the cyclopeptide framework (diglycyl gramicidin S) affects the membrane in a way similar to that of natural gramicidin . Washing of gramicidin-treated membranes with NaCl enhances the inhibitory effect of the antibiotic on membrane enzymes . The data obtained suggest that in addition to ionic interactions some hydrophobic interactions also occur during gramicidin S binding to the bacterial membrane, probably at the expense of a hydrophobic peptide ring . It is assumed that gramicidin S, similar to Ca2+ and some other membranotropic agents provides for phase separation of negatively charged phospholipids from other groups of phospholipids, manifesting itself in an appearance of "frozen" sites on the membrane which destroys its barrier properties . This is due to the formation of ionic bonds of negatively charged phospholipids . Simultaneously, unlike Ca2+, gramicidin S, when interacting with membrane proteins, prevents their redistribution in more liquid parts of the membrane, which results in a situation when the respiratory enzymes become surrounded by alkyl chains with restricted motion.

J Biochem (Tokyo), 1977 Feb, 81(2), 389 - 94
Effects of polyamines on the degradation of ribonucleic acids by polynucleotide phosphorylase of Micrococcus luteus; Igarashi K et al.; The effects of polyamines on the breakdown of synthetic polynucleotides {poly(A), poly(C), and poly(U)} by polynucleotide phosphorylase {polyribonucleotide: orthophosphate nucleotidyltransferase, EC 2.7.7.8} from Micrococcus luteus have been studied . Although the breakdown of all the synthetic polynucleotides tested was stimulated by polyamines, the degree of stimulation by polyamines was in the order poly(C) greater than poly(A) greater than poly(U) at pH 7.5 . However, the difference in degree of stimulation among polynucleotides decreased as the pH or monovalent cation concentration was increased . In the presence of heparin, an inhibitor of polynucleotide phosphorylase hydrolysis of polynucleotides, spermidine clearly stimulated the breakdown of poly(C) and poly(A), while the breakdown of poly(U) was stimulated only slightly by the addition of spermidine . Although binding of {14C}spermine to polynucleotide phosphorylase was observed by gel filtration, the amount of spermine bound to the enzyme was much less than that to RNA.

Ann Immunol (Paris), 1977 Jan-Mar, 128(1-2), 345 - 9
{Evolution of the immune response against Micrococcus lysodeikticus}; Strosberg AD et al.; The immune response of rabbits immunized with Micrococcus lysodeikticus freeze-dried bacteria was studied by following the variation of the affinity and the heterogeneity of the antibodies during immunization . Partial or complete amino acid sequences were determined on the isolated light and heavy chains, and comparative studies were initiated in litter mates . No relationship between the affinity and the restriction in heterogeneity was observed . Sequences are indistinguishable from those reported for antibodies of other specificities.

Biokhimiia, 1976 Dec, 41(12), 2212 - 9
{Specific modification of free lysine amino groups of histidine decarboxylase from Micrococcus sp . n . by trinitrobenzene sulfonic acid}; Semina LA et al.; It has been found that 14 lysine residues are accessible for trinitrobenzene sulfonic acid (TNBS) in the molecule of histidine decarboxylase (HDC) . The other 62 lysine residues in the molecule of native HDC are masked and inaccessible for TNBS . It is demonstrated that the SH- and alpha-amino groups of methionine are not modified by TNBS . A correlation between the decarboxylase activity of the enzyme and the degree of its trinitrophenylation has been studied . HDC, whose molecule contains 3--9 TNP groups, retains up to 90--97% of its initial activity . Trinitrophenylation of 14 lysine residues induces inactivation of HDC by 33--34%, which probably depends on conformational changes or steric hindrances, occurring in the catalytic site of the modified active centre of HDC . Using circular dichroism and fluorescence methods as well as disc-electrophoresis in polyacrylamide gel, it has been shown that trinitrophenylation does not cause any significant changes in the enzyme structure . The TNP groups have been found to be localized in the large and small subunits of the HDC molecule.

Eur J Biochem, 1976 Dec, 71(1), 131 - 4
Quantitative determination of N-acetylglucosamine residues at the non-reducing ends of peptidoglycan chains by enzymic attachment of {14C}-D-galactose; Schindler M et al.; The ability of human milk galactosyltransferase to attach D-galactose residues quantitatively to the C-4 of N-acetylglucosamine moieties at the ends of oligosaccharides has been utilized for the specific labeling and quantitative determination of the chain length of the glycan moiety of the bacterial cell wall . The average polysaccharide chain length of the soluble, uncrosslinked peptidoglycan secreted by Micrococcus luteus cells on incubation with penicillin G was studied with this technique and found to be approximately 70 hexosamines long . Furthermore, the peptidoglycan chain length of Escherichia coli sacculi of different cell shapes and dimensions was determined both in rod-shaped cells and in filaments induced by temperature shift of a division mutant or by addition of cephalexin or nalidixic acid . The average chain length found in most of these sacculi was between 70 and 100 hexosamines long . Small spherical 'mini' cells had chain lengths similar to those of the isogenic rod-like cells.

Cell, 1976 Dec, 9(4 Pt 1), 627 - 32
A comparison of the structure of chicken erythrocyte and chicken liver chromatin; Morris NR; The structure of chicken erythrocyte and chicken liver chromatin has been studied by enzymatic digestion with micrococcal nuclease and DNAase I . Comparison of the fragments produced by brief digestion with micrococcal nuclease indicates that chicken erythrocyte chromatin has a longer nucleosome repeat than chicken liver chromatin, 212 base pairs as opposed to 200 base pairs (bp) . More extensive digestion with micrococcal nuclease demonstrates that both tissues have 140 bp mucleosome cores . The difference in the length of the nucleosome repeat must therefore result from a difference in the length of the DNA linker between cores . Chicken erythrocyte chromatin is known to contain a tissue-specific, H1-like histone, H5, and to be genetically dormant . A model is presented to explain how changes in histone H1 could cause changes in the nucleosome repeat length and thereby alter the genetic activity of chromatin.

Nucleic Acids Res, 1976 Dec, 3(12), 3271 - 91
Chromatin nu bodies: isolation, subfractionation and physical characterization; Olins AL et al.; Monomer chromatin subunit particles (nu1) have been isolated in gram quantities by large-scale zonal centrifugation of micrococcal nuclease digests of chicken erythrocyte nuclei . nu1 can be stored, apparently indefinitely, frozen in 0.2 mM EDTA (pH 7.0) at less than or equal to 25 degrees C . Aliquots of the stored monomers have been subfractionated by dialysis against 0.1 M KCl buffers into a soluble fraction containing equimolar amounts of H4, H3, H2A, H2B associated with a DNA fragment of approximately 130-140 nucleotide pairs, and a precipitated fraction containing all of the histones including H5 and H1 associated with DNA fragments . The total nu1 and the KCl-soluble fraction of nu1 have been examined by sedimentation, diffusion, sedimentation equilibrium ultracentrifugation, low-angle X-ray diffraction, and electron microscopy . Physical parameters from all of these techniques are presented and correlated in this study.

Biochim Biophys Acta, 1976 Dec 1, 454(2), 309 - 18
Interaction of a fluorescent reagent, fluorescein mercuric acetate, with nucleic acids; Takeuchi S et al.; Fluorescein mercuric acetate (fluorescein Hg Ac), which is a fluorescent thiol reagent, was shown to bind to various nucleic acids by measuring the changes in its absorption and fluorescence properties . Up to a critical concentration of free fluorescein Hg Ac (1-10(-7) M for calf thymus DNA, with 42% GC, and 2-10(-7) M for Micrococcus lysodeikticus DNA, with 72% GC) this reagent appears to bind selectively to single-stranded sections in DNA . Above this critical concentration, cooperative binding to double helical DNA occurs, and denatured DNA is obtained after removal of bound fluorescein Hg Ac by dialysis against 1 M KCl . These facts indicate that fluorescein Hg Ac causes the denaturation of double helical DNA prior to binding as has been shown in the case of methylmercuric hydroxide . The binding of fluorescein Hg Ac to DNA is much stronger than that of methylmercuric hydroxide . The number of total binding sites for fluorescein Hg Ac is close to the number of base pairs for both calf thymus DNA and M . lysodeikticus DNA . Furthermore, it was shown that fluorescein Hg Ac binds to thymidine, deoxyguanosine, poly(U) and poly(G) . Since fluorescence quenching of fluorescein Hg Ac accompanies its complex formation with DNA and the affinity is markedly high as indicated by the association constant of 6.8-10(7) M(-1) for single-stranded calf thymus DNA, fluorescein Hg Ac can be used for the structural studies of small amounts of nucleic acids.

Proc Natl Acad Sci U S A, 1976 Dec, 73(12), 4382 - 6
Biochemical evidence of variability in the DNA repeat length in the chromatin of higher eukaryotes; Compton JL et al.; Biochemical evidence is presented which confirms that the DNA repeat length in micrococcal nuclease (spleen endonuclease, nucleate 3'-oligonucleotidohydrolase, EC 3-1-4-7) digests of Chinese hamster ovary chromatin is shorter than that of rat liver chromatin {J.L . Compton, R . Hancock, P . Oudet, and P . Chambon (1976) Eur . J . Biochem., in press} . A survey of available cells has shown that the DNA repeat length of the chromatin of higher eukaryotes varies widely . A value of 196 base pairs was found for cells of all mature tissues, regardless of the source of the tissue, whereas smaller values were found for cells of actively dividing tissues and larger values were found for a genetically inactive cell . Although the DNA repeat length of the chromatin of cells in culture was usually shorter than 196 base pairs, there was no general correlation between the size of the chromatin DNA repeat length and the rate of cell division or the functional state of the cell in culture . Examination of extensive micrococcal nuclease digests suggests that the chromatin subunits of all of the higher eukaryotic cells we have studied contain a core with approximately 140 base pairs of DNA.

Can J Microbiol, 1976 Dec, 22(12), 1680 - 90
Sulfur amino acid auxotrophy in Micrococcus species isolated from human skin; Farrior JW et al.; Since methionine and (or) cysteine are required by a large percentage of natural auxotrophic Micrococcus strains isolated from human skin, investigations were directed to determine the specific enzymes affected in sulfur amino acid biosynthesis . Known intermediates in the interrelated cysteine and methionine biosynthetic pathways were tested as growth stimulants . Based on these growth studies, sulfur amino acid auxotrophs were grouped into three cysteine classes and five methionine classes . Selected auxotrophs of M . luteus had deficiencies in ATP sulfurylase (EC 2.7.7.4) and adenosine-5-sulfatophosphate (APS) kinase (EC 2.7.1.25), sulfite reductase (EC 1.8.1.2), serine transacetylase (EC 2.3.1.30), or beta-cystathionase (EC 4.4.1.8) activity; auxotrophs of M . lylae had deficiencies in sulfite reductase and serine transacetylase, beta-cystathionase, or N5, N10-methyltetrahydrofolate reductase (EC 1.1.1.68) activity; all auxotrophs of M . sedentarius tested had deficiencies in N5,N10-methyltetrahydrofolate reductase activity; auxotrophs of M . nishinomiyaensis had deficiencies in adenosine-3-phosphate-5-sulfatophosphate (PAPS) reductase, sulfite reductase, serine transacetylase, or N5,N10-methyltetrahydrofolate reductase activity; auxotrophs of M . varians had deficiencies in APS kinase, PAPS reductase, sulfite reductase, homoserine omicron-transsuccinylase, beta-cystathionase, or N5,N10-methyltetrahydrofolate reductase activity; auxotrophs of M . kristinae had deficiencies in serine transacetylase or cystathionine-gamma-synthase (EC 4.2.99.9) activity; auxotrophs of M . roseus had deficiencies in PAPS reductase, sulfite reductase, or serine transacetylase activity . Results of studies with various mutagens suggested that sulfur amino acid auxotrophy was primarily the result of a single base substitution in usually one or two of the genes controlling biosynthesis . A preliminary study of the amino acid composition of sweat suggested that this important source of nutrients does not contain adequate amounts of cysteine for the growth of cysteine auxotrophs but contains methionine that may be utilized in place of cysteine.

Eur J Biochem, 1976 Nov 15, 70(2), 555 - 68
Biochemical and electron-microscopic evidence that the subunit structure of Chinese-hamster-ovary interphase chromatin is conserved in mitotic chromosomes; Compton JL et al.; Biochemical and electron microscopic studies demonstrate that the subunit structure of Chinese hamster ovary cell interphase chromatin is conserved in mititic chromosomes . Digestion of purified chromosomes or nuclei with micrococcal nuclease produces DNA in discrete size classes, as visualized by polyacrylamide gel electrophoresis, which are common to the two materials . Early in digestion the DNA fragments are integral multiples of a monomer approximately 177 base pairs in length, whereas after extensive digestion the remaining DNA fragments migrate ahead of the monomer position . The size of the repeating DNA unit was confirmed as being smaller than that produced by micrococcal nuclease digestion of rat liver nuclei by direct comparison . Electron microscopy of partially unravelled chromosomes at low ionic strength shows tightly packed spheres (nucleosomes) approximately 12 nm in diameter which are often arranged as linear chains . Chromosomal material prepared for electron microscopy after varying extents of micrococcal nuclease digestion is composed of fragments containing pregressively fewer nucleosomes, which parallels the loss of high DNA multimer bands in gel electrophoresis . Material unravelled from chromosomes in the presence of NaCl consists of nucleosomes packed packed in a different configuration which suggests the origin of higher order structures in chromosomes.

Eur J Biochem, 1976 Nov 15, 70(2), 543 - 53
Subunit structure of simian-virus-40 minichromosome; Bellard M et al.; Electron microscopic evidence indicates that Simian virus 40 (SV40) minichromosomes extracted from infected cells consist of 20 +/- 2 nucleosomes, each containing 190 -- 200 base pairs of DNA . About 50% of the nucleosomes are not close together, but connected by segments of DNA of irregular lengths which correspond to about 15% of the viral genome, irrespective of the ionic strength . Micrococcal nuclease digestion studies show that there is about 200 base pairs of DNA in the biochemical unit of SV40 chromatin . Therefore, the visible internucleosomal DNA of the SV40 minichromosome does not arise from an unfolding of a fraction of the 190 - 200 base pairs of DNA initially wound in the nucleosome . These results support the chromatin model which proposes that the same DNA length is contained in the nucleosome and the biochemical unit . Results from extensive micrococcal nuclease digestion suggest that an SV40 nucleosome consists of a 'core' containing a DNA segment of about 135 base pairs associated to a DNA fragment more susceptible to nuclease attack . The addition of histone H1 results in a striking condensation of the SV40 minichromosome, which supports the assumption that histone H1 is involved in the folding of chromatin fibers.

Proc Natl Acad Sci U S A, 1976 Nov, 73(11), 3966 - 70
Selective digestion of transcriptionally active ovalbumin genes from oviduct nuclei; Garel A et al.; Analysis of the DNA of isolated nucleosomes suggests that virtually all genomic DNA sequences are organized in this basic chromatin subunit . In this report, we demonstrate that although histones reside on the transcriptionally active ovalbumin genes in the oviduct, the organization of proteins about this gene renders it highly sensitive to deoxyribonuclease I (deoxyribonucleate 5'-oligonucleotidohydrolase, EC 3.1.4.5) . Treatment of oviduct nuclei from the laying hen with pancreatic deoxyribonuclease I results in the preferential digestion of over 70% of the ovalbumin sequences when only 10% of the total nuclear DNA has been solubilized . Treatment of liver nuclei does not reveal selective sensitivity of these genes to DNase I . Furthermore, regions of DNA not actively transcribed, such as the endogenous leukosis virus genes in the oviduct, are not selectively degraded by this enzyme . Similar digestions with micrococcal nuclease, however, reveal no specific digestion of transcriptionally active chromatin . These data confirm the observations of H . Weintraub and M . Groudine {(1976) Science 193, 848-856} and suggest we are dealing with an aspect of structure that may be necessary to permit transcription of the chromatin complex.

Nucleic Acids Res, 1976 Nov, 3(11), 2879 - 93
Conformational state of DNA in chromatin subunits . Circular dichroism, melting, and ethidium bromide binding analysis; Lawrence JJ et al.; This study compares some physical properties of DNA in native chromatin and mono-, di-, trinucleosomes obtained after mild micrococcal nuclease digestion . Melting curves and derivatives are shown to be very similar from one sample to another although a shift from 79 to 82 degrees C is observed between the mainly monophasic peak of multimers and chromatin . Careful analysis of the positive band of the circular dichroism spectra shows the appearance of a shoulder at 275nm, the intensity of which increases from the mono- to the di- and trinucleosome . This shoulder is maximum for native chromatin . At the same time binding isotherms of ethidium - bromide are characterized by two highly fluorescent binding sites for all the samples but the product KN of the apparent binding constant of the higher affinity binding sites by the apparent number of those sites increases from the mono- to the di- and trinucleosome . There again the valus is maximum for native chromatin . Such results strongly suggest that the native state of chromatin requires something more than the indefinite repeat of an elementary subunit.

Cell, 1976 Nov, 9(3), 423 - 9
Studies on the mode of segregation of histone nu bodies during replication in HeLa cells; Seale RL; Two models were tested for the mode of distribution of histone nu bodies at the replication fork . The replication fork was labeled by brief incubation of cells with 3H-thymidine . Nuclei were isolated and digested with low levels of micrococcal nuclease, and the kinetics of cleavage of the pulse-labeled chromatin DNA were compared to the kinetics of clevage of perental chromatin DNA . In chromatin labeled for 30 sec to 10 min, the rate of cleavage of the pulse-labeled region into monomeric nu body-sized units exceeded the rate of cleavage of parental chromatin by a factor of 2, but did not approach the predicted value of 5-6 for random segregation . This value dropped to 1.6 in 15 min and was equivalent to perental chromatin in 20 min labeling experiments . DNA synthesized in the presence of cycloheximide was also digested at twice the rate of parental chromatin DNA . A Poisson analysis of the kinetics of cleavage by micrococcal nuclease further confirmed these observations . The predicted difference in the rate of production of monomeric, dimeric, and trimeric deoxyribonucleoprotein units was very similar to the experimental values of both total chromatin and nascent chromatin . Thus the nu body spacings in newly replicated chromatin closely approximate those in parental chromatin . These results agree well with a conservative or nondispersive model of nucleosome distribution in which the proteins are associated with one of the two daughter chromosomes during replication.

Nucleic Acids Res, 1976 Nov, 3(11), 2923 - 8
A deoxyadenylate kinase activity associated with polynucleotide phosphorylase from Micrococcus luteus; Craine JE et al.; We report here the presence of two enzymatic activities associated with highly purified preparations of polynucleotide phosphorylase from Micrococcus luteus . The first, a nuclease activity, which is not separated from the phosphorylase on hydroxylapatite, may be due to substitution of H2O for phosphate in the phosphorolysis reaction . The second activity, a deoxyadenylate kinase, the bulk of which is not resolved from the phosphorylase using gel filtration, sucrose density gradient centrifugation, DEAE-Sephadex, or hydroxylapatite chromatography, may represent a new activity of polynucleotide phosphorylase or be due to an enzyme which is tightly bound to the phosphorylase . Several properties of the kinase are described and its possible significance with respect to the overall enzyme mechanism is discussed.

Proc Natl Acad Sci U S A, 1976 Oct, 73(10), 3458 - 62
Identification of nonhistone chromatin proteins in chromatin subunits; Liew CC et al.; Rat liver chromatin was digested by micrococcal nuclease . More than 80% of the enzyme-digested chromatin could be recovered after centrifugation . Treatment with sodium deoxycholate and Triton X-100 at concentrations of 0.5% in the final chromatin suspension gave a higher recovery . Chromatin subunits were fractionated on a 5-30% linear sucrose density gradient . Approximately 35% of the chromatin subunits could be recovered from the gradient . Chromatin subunits and their DNA fragments were identified by gel electrophoresis and ultracentrifugation . The presence of nonhistone chromatin proteins (NHCP) in chromatin subunits was demonstrated by the following criteria: (i) Quantitative analysis showed that the mass ratio of histone to NHCP, in the presence or absence of detergents, was 1:0,25 or 1:0.1, respectively . (ii) After the removal of acid-soluble protein from the subunits, it was found that most of the phenol-soluble NHCP were similar to total chromatin NHCP . However, four major fractions of these phenol-soluble NHCP were found to be enriched in the subunits as identified by two-dimensional polyacrylamide gel electrophoresis . (iii) Experiments using an exchange of isotope-labeled and nonlabeled chromatin showed that NHCP were tightly bound to the chromatin subunits.

Biokhimiia, 1976 Oct, 41(10), 1810 - 8
{Application of phase partition method for the fractionation of hydrophobic membrane proteins}; Lukoianova MA et al.; Phase partition method in a two-phase polyethylene glycol-dextrane system has been applied to fractionation in Triton X-100 of hydrophobic membrane proteins from Micrococcus lysodeikticus . This method allowed to separate the cytochrome b556 from other cytochromes . Spectral and gel electrophoretic patterns of isolated cytochrome are given.

Biokhimiia, 1976 Oct, 41(10), 1760 - 5
{Amino acid sequence in tryptic peptides of maleylated Micrococcus sp . n . histidine decarboxylase beta-polypeptide chain}; Alekseeva AE et al.; Maleilated histidine decarboxylase beta-polypeptide chain, containing 3 arginine residue, was hydrolysed by trypsin . 4 non-overlapping homogenous peptides were isolated, 3 of them containing one arginine residue and the 4th peptide being C-terminal fragment of beta-chain . beta-Polypeptide chain is found to consist of 78 amino acid residues and to have molecular weight of 8456 . Primary structure of each peptide and their possible sequence in beta-chain are determined.

Nucleic Acids Res, 1976 Oct, 3(10), 2633 - 44
Nuclease digestion in between and within nucleosomes; Greil W et al.; In the course of digestions of rat liver nuclei with micrococcal nuclease the size of the nucleosomal DNA is shortened by 50-60 nucleotide pairs from starting lengths of about 200, 400, 600, 800, etc . nucleotide pairs in the monomeric and oligomeric nucleosomes, respectively . Acid soluble DNA material is created relatively slowly as compared to the rate of formation of subnucleosomal material . More DNA with lengths in between the 200, 400, etc . nucleotide pairs of nucleosomal DNA is formed when digestions with micrococcal nuclease are carried out at 0 to 10 degrees C compared to 40 degrees C . With DNAase II, on the other hand, formation of a 200 nucleotide pair pattern is favoured at the low temperatures . Apparently, the accessibility of potential cleavage sites in between and within nucleosomes depends strongly on the conditions of digestion . Possible reasons for this dependence are discussed.

Eur J Biochem, 1976 Oct 1, 69(1), 265 - 72
Substrate specificity of the ultraviolet-endonuclease from Micrococcus luteus . Endonucleolytic cleavage of depurinated DNA; Tomilin NV et al.; The ultraviolet-endonuclease isolated from Micrococcul luteus, specific for pyrimidine dimers, is able to attack not only ultraviolet-irradiated DNA (leading to 3'OH-5'PO4 single-strand breaks) but also superhelical covalently-closed circular DNA of phage lambda damaged by heating at 70 degrees C, pH 5.93 . The number of endonuclease-sensitive defects in the DNA corresponds to the number of alkalilabile bonds (apurinic sites) induced by heating . Competition between ultraviolet-induced lesions and apurinic sites for ultraviolet-endonuclease is demonstrated; the affinity of the enzyme for pyrimidine dimers is about three times that for apurinic sites . Both activities of the ultraviolet-endonuclease are inactivated at 50 degrees C at the same rate . The ultraviolet-endonuclease is able to reduce the infectious activity of depurinated lambda DNA towards Ca2+-treated uvr+ and uvr A Escherichia coli cells . It is concluded that both pyrimidine dimers and apurinic sites can be recognized by one and the same enzyme (the ultraviolet-endonuclease).

Biophys J, 1976 Oct, 16(10), 1155 - 64
Significance of dimers to the size of newly synthesized DNA in UV-irradiated Chinese hamster ovary cells; Clarkson JM et al.; DNA synthesized after UV irradiation is smaller than that in unirradiated cells even when pulse-labeling times are increased to compensate for the overall reduction in the rate of DNA replication . By isolating newly replicated DNA, incubating it with dimer-specific endonuclease from Micrococcus luteus, and analyzing it on alkaline sucrose gradients, we have been able to demonstrate that this DNA is synthesized in segments corresponding in size to the interdimer distance on the parental strand . In addition, the same DNA analyzed on neutral gradients shows no reduction in molecular weight as a result of UV irradiation and/or endonuclease digestion . Our data are thus inconsistent with the presence of "gaps" in newly synthesized DNA opposite the dimers on the parental strand . We suggest that if such gaps are produced as a result of delayed synthesis around dimers, they are filled before the growing point reaches the next dimer.

J Virol, 1976 Oct, 20(1), 142 - 56
Replicative bacteriophage DNA synthesis in plasmolyzed T4-infected cells: evidence for two independent pathways to DNA; Wovcha MG et al.; Bacteriophage T4-infected Escherichia coli rendered permeable to nucleotides by sucrose plasmolysis exhibited two apparently separate pathways or channels to T4 DNA with respect to the utilization of exogenously supplied substrates . By one pathway, individual labeled ribonucleotides, thymidine (tdR), and 5-hydroxymethyl-dCMP could be incorporated into phage DNA . Incorporation of each of these labeled compounds was not dependent upon the addition of the other deoxyribonucleotide precursors, suggesting that a functioning de novo pathway to deoxyribonucleotides was being monitored . The second pathway or reaction required all four deoxyribonucleoside triphosphates or the deoxyribonucleoside monophosphates together with ATP . However, in this reaction, dTTP was not replaced by TdR . The two pathways were also distinguished on the basis of their apparent Mg2+ requirements and responses to N-ethylmaleimide, micrococcal nuclease, and to hydroxyurea, which is a specific inhibitor of ribonucleoside diphosphate reductase . Separate products were synthesized by the two channels, as shown by density-gradient experiments and velocity sedimentation analysis . Each of the pathways required the products of the T4 DNA synthesis genes . Furthermore, DNA synthesis by each pathway appeared to be coupled to the functioning of several of the phage-induced enzymes involved in deoxyribonucleotide biosynthesis . Both systems represent replicative phage DNA synthesis as determined by CsCl density-gradient analysis . Autoradiographic and other studies provided evidence that both pathways occur in the same cell . Further studies were carried out on the direct role of dCMP hydroxymethylase in T4 DNA replication . Temperature-shift experiments in plasmolyzed cells using a temperature-sensitive mutant furnished strong evidence that this gene product is necessary in DNA replication and is not functioning by allowing preinitiation of DNA before plasmolysis.

J Virol, 1976 Oct, 20(1), 170 - 6
Polyadenylate sequences of human rhinovirus and poliovirus RNA and cordycepin sensitivity of virus replication; Nair CN et al.; The polyadenylate {poly(A)} content of the genome RNA of human rhinovirus type 14 (HRV-14) is nearly twice as large as that of the genome RNA of poliovirus type 2 . The poly(A) content of viral RNA was determined to be the RNase-resistant fraction of 32P-labeled viral RNA extracted from purified virions . Polyacrylamide gel electrophoresis indicated that the poly(A) sequences of HRV-14 are more heterogenous and on an average larger than those of poliovirus RNA . On the basis of susceptibility to micrococcal polynucleotide phosphorylase the rhinovirus genome terminates in poly(A) . Replication of both viruses is almost totally inhibited by cordycepin at 50 mug/ml . At lower concentrations, rhinovirus replication is more sensitive to cordycepin than poliovirus replication . Addition of cordycepin (75 mug/ml) to infected culture prior to or during viral RNA replication results in more or less complete inhibition of virus-specific RNA synthesis . The results do not indicate that cordycepin sensitivity of either virus is due to preferential inhibition of viral poly(A) synthesis by this antibiotic.

Biochemistry, 1976 Sep 21, 15(19), 4305 - 12
Histone compostion of chromatin subunits studied by immunosedimentation; Simpson RT et al.; Chromatin subunits were prepared from HeLa cells by in situ digestion of nuclear DNA with micrococcal nuclease followed by sucrose gradient sedimentation . These 11S chromosomal particles (nucleosomes) contain a DNA fragment 140--180 base pairs long and an equal mass of histones, H2A, H2B, H3, and h4 . nucleosomes were incubated with purified antibodies to histones H2A and H2B and to hemoglobin A, and the resulting complexes were analyzed by ultracentrifugation . Of these, only anti-H2B bound specifically to nucleosomes . When sufficient antibody was present, all (greater than 98%) the nucleosomes sedimented with increased velocities, indicating that all chromosomal particles contain H2B, as suggested by previous electron microscopic studies (Bustin, M., Goldblatt, D., and Sperling, R . (1976), Cell 7, 297) . The amount of antibody reacting with H2B in the nucleosome was quantitated by densitometric scanning of gel electrophoresis patterns of the proteins in various nucleosome-anti-H2B complexes separated by sedimentation on isokinetic sucrose gradients . Under conditions where all particles had increased sedimentation velocities, from 1 to 3 IgG molecules are bound to each nucleosome, the ratio increasing from top to bottom of the sedimenting peak . When nucleosomes are thus dispersed on the basis of reaction with anti-H2B, the ratios of H2A to H4 and of (H2B + H3) to H4 are identical (+/- 8%) for all fractions, suggesting that each nucleosome has an identical histone complement, two each of histones H2A, H2B, H3, and H4 . Confidence limits for exclusion of other possible octamers are presented . The variation in ratio of bound antibody to nucleosome probably reflects a normal distribution during the titration, although differential exposure of H2B antigenic determinants in several populations of nucleosomes cannot be excluded as an explanation . The method use should be generally applicable to further studies of the composition and function of nucleosomes.

Poult Sci, 1976 Sep, 55(5), 1749 - 56
Lysozyme in hen blood serum; Sato Y et al.; Hen blood serum (White Leghorn) possessed the lytic action against Micrococcus lysodeikticus which was less than one-thousandth of egg white obtained from hens of the same species, suggesting that lysozyme was present . The filter-sterilized hen blood serum also inhibited the growth of M . lysodeikticus in broth culture . The isolated lysozyme, purified by column chromatography and gel filtration, proved to be a basic protein with a low molecular weight (about 15,000), active against M . lysodeikticus, and more stable at acidic pH values than at alkaline pH values when heated . In amino acid composition, the isolated serum lysozyme had slightly higher proline and lower aspartic acid content than hen egg white lysozyme . The blood serum lysozyme was less heat stable at various pH values (4.5 to 8.4) than egg white lysozyme.

Biokhimiia, 1976 Sep, 41(9), 1628 - 35
{Isolation of cytochrome b556 from the membranes of Micrococcus lysodeikticus bacteria}; Lukoianova MA et al.; Proteins and cytochrome b556 were solubilized from Micrococcus lysodeikticus membranes using Triton X-100 treatment . Passing of this preparation through DEAE cellulose column in the presence of Triton X-100 made possible to isolate cytochrome b556 from other membrane cytochromes and to purify it up to the content of 2.3 nmol per mg of protein . The prostetic group of cytochrome b556 is determined to be protoheme for the spectrum of alkaline pyridinehemochrome.

Biokhimiia, 1976 Sep, 41(9), 1584 - 7
{Localization of pyruvic acid in the histidine decarboxylase of Micrococcus sp . n.}; Alekseeva AE et al.; A fragment containing the pyruvic acid residue is isolated from hymotryptic hydrolyzate of alpha-polypeptide chain of carboxymethylated histidine decarboxylase (HD) 14C-phenylhydrasone . The pyruvate residue is estimated to be bind with alpha-amino group of N-terminal phenylalanine in alpha-polypeptide chain . N-terminal alanine is found in HD alpha-polypeptide chain after its reductive amination . It makes possible to determine the estimation of N-terminal amino acid sequence in HD alpha-chain.

Nucleic Acids Res, 1976 Sep, 3(9), 2255 - 66
Preparation and physical characterization of a homogeneous population of monomeric nucleosomes from HeLa cells; Whitlock JP Jr et al.; We describe a method of isolating a homogeneous population of "trimmed" monomeric nucleosomes from Hela cells . These nucleoprotein particles contain a 140 +/- 5 base pair length of DNA and have a histone/DNA ratio of 1.2 . They lack H1 and contain equal amounts of the four smaller histones . The DNA contains no single strand nicks . The particles sediment with an S20,w of 11S in D2O density gradients . After formaldehyde fixation, they band at a density of 1.4370 in neutral CsCl . Digestion of nucleosomes with either micrococcal nuclease or DNase I generates the same pattern of DNA fragments observed when intact nuclei are digested . Circular dichroism spectra indicate that the 280 nm positive ellipticity maximum of nucleosomes is about one-half that of chromatin . In the presence of 6 M urea, nucleosomes sediment with an S20,w of 6S, have a multiphasic thermal denaturation profile, and exhibit a circular dichroic spectrum nearly identical to that of B-form DNA . Our yield of purified nucleosomes (10-15% of the input DNA) is similar to the yields of other methods; our nucleosome population is substantially more homogeneous than those previously reported.

J Assoc Off Anal Chem, 1976 Sep, 59(5), 1113 - 7
Improved microbiological procedure for determining bacitracin in premixes and mixed feeds; Fassbender CA et al.; An improved microbiological procedure is presented for determining bacitracin in premixes and mixed feeds . Premixes are extracted with acidic 50% aqueous methanol, and mixed feeds are extracted with 50% dimethylformamide after washing with acetone to remove fats and pigments . Extracts are diluted with pH 6.0 phosphate buffer and assayed by using a 2-point assay system with Micrococcus flavus as the test organism . The simpler extraction coupled with the 2-point assay system measured bacitracin levels as low as 10 g/ton . Accuracy and repeatability of the 2-point system were at least equivalent to those for official AOAC methods.

Can J Microbiol, 1976 Sep, 22(9), 1336 - 44
Respiratory activity as a determinant of radiation survival response; Bruce AK et al.; Respiration is depressed in irradiated bacteria reaching a minimum level in most strains at 1-3 h after exposure when incubated in growth medium . Since a delay in response is observed, direct action on respiratory enzymes is unlikely . The dosage response of respiration varies widely in the strains studied with Do's from 15 kR for Escherichia coli BS-1 to 1200 kR for Micrococcus radiodurans . All strains exhibit two-component dosage-response curves . Escherichia coli BS-1 uniquely possesses a positive-sloped second component suggesting a major disruption of respiratory control . A relationship exists between the responses of respiration and survival to a 50-kR exposure in the strains studied . When E . coli B/r is grown in 0.4% glucose reaching a pH of 5.3, a condition known to increase radiation survival considerably, a large increase in radioresistance of respiration is found . 2-Mercaptoethylamine (MEA), a radioprotective agent, also produces proportionate radioprotection of respiration and survival . In M . radiodurans protection is afforded to respiration at doses which produce no measurable effect on survival . These facts suggest that respiration is a major factor in influencing cell survival and may be the principal mechanism through which chemical agents modify radiation response.

Nucleic Acids Res, 1976 Sep, 3(9), 2277 - 91
Satellite DNA sequence content of polylysine-titratable and nuclease-resistant fractions of mouse liver hepatoma chromatin; Duerksen JD et al.; Micrococcal nuclease digestion of mouse TLT liver hepatoma chromatin proceeds rapidly to the point where approximately 35% of the DNA is recoverable by centrifugation of the chromatin DNA through 3M CsCl . The satellite DNA sequence content of this recoverable DNA is the same as whole chromatin DNA (10%) . The 11s (penultimate digestion product) monomer, as well as intermediate multiples and relatively undigested large chromatin segments are separable on steep hlycerol gradients . The DNA isolated from these fractions also contains the normal 10% satellite DNA content . Progressive polylysine titration of chromatin followed by nuclease digestion gives anomalous recoveries of DNA but, nonetheless, the satellite sequence content titration of chromatin, followed by pronase and then nuclease digestion, again gave recoverable DNA with a satellite sequence content of 10% . These results are discussed in terms of the conclusion that nucleosome (or upsilon-body) structures are distributed in a random fashion over the genome.

J Biol Chem, 1976 Aug 25, 251(16), 4833 - 8
Specific herpes simplex virus-induced incorporation of 5-iodo-5'-amino-2',5'-dideoxyuridine into deoxyribonucleic acid; Chen MS et al.; 5-Iodo-5'-amino-2',5'-dideoxyuridine (AIdUrd) is a novel thymidine analog which inhibits herpes simplex virus, type 1 (HS-1 virus) replication in the absence of detectable host toxicity . When murine, simian, or human cells in culture are treated with {125I}AIdUrd for up to 24 hours essentially none of the nucleoside becomes cell-associated . In contrast, upon HS-1 virus infection significant radiolabel is detected in both nucleotide pools and in DNA . The major acid-soluble metabolite has been shown by enzymic and chromatographic analysis to be the 5'-triphosphate of AIdUrd . DNA from HS-1 virus-infected Vero cells labeled with {14C}thymidine, 5-{125I}iodo-2'-deoxyuridine (IdUrd), or {125I}AIdUrd was isolated by buoyant density centrifugation and subjected to digestion by pancreatic DNase I, spleen DNase II, micrococcal nuclease, spleen, and venom phosphodiesterases . Analysis of the digestion products clearly indicate that AIdUrd is incorporated internally into the DNA structure . DNA containing AIdUrd therefore contains phosphoramidate (P-N) bonds, known to be extremely acid-labile . The selective HS-1 virus-induced phosphorylation of AIdUrd and its subsequent incorporation into DNA may account for the unique biological activity of the AIdUrd nucleoside.

Eur J Biochem, 1976 Aug 16, 67(2), 469 - 76
Membrane-bound F1 ATPase from Micrococcus Sp . ATCC 398E . Purificationa and characterization ny affinity chromatography; Hulla FW et al.; A chemically reactive ATP analogue, 6-{(3-carboxy-4-nitrophenyl)thio}-9-beta-D-ribofuranosylpurine 5'-triphosphate (Nbs6ITP) has been synthesized . It has the ability to form stable thioether bonds between the 6-position of the purine ring and aliphatic mercapto groups . The nucleotide moiety of the reagent has been covalently bound to agarose, via iminobispropylamine and N-acetyl-homocysteine as space with the purpose of producing an affinity chromatography material . The affinity matrix binds solubilized F1 ATPase from a crude extract of Micrococcus sp . membranes . Afterwards the enzyme can be selectively eluted from the column at a defined ATP concentration . This method is superior to the conventional purification with respect to speed and convenince of the preparation . The affinity chromatography leads in a one-step process to the same purity to enzyme, substituting several steps of the conventional method . In addition, the affinity matrix was used for binding studies . Although the presence of Mg2+ ions is a prerequisite for the hydrolysis of nucleoside 5'-triphosphates, evidence is presented indicating that the binding of the nucleoside triphosphates to highly purified F1 ATPase from Micrococcus sp . appears not to be influenced by Mg2+ ion concentrations so far examined.

Eur J Biochem, 1976 Aug 1, 67(1), 247 - 56
An efficient mRNA-dependent translation system from reticulocyte lysates; Pelham HR et al.; A simple method is described for converting a standard rabbit reticulocyte cell-free extract (lysate) into an mRNA-dependent protein synthesis system . The lysate is preincubated with CaCl2 and micrococcal nuclease, and then excess ethyleneglycol-bis(2-aminoethylether)-N,N'-tetraacetic acid is added to chelate the Ca2+ and inactivate the nuclease . Lysates treated in this way have neglibible endogenous amino acid incorporation activity, but 75% of the activity of the original lysate can be recovered by the addition of globin mRNA . The efficiency of utilisation of added mRNA and the sensitivity of the system are both very high . No residual nuclease activity could be detected, and the tRNA is functionally unimpaired . Several different species of mRNA have been shown to be translated efficiently into full-sized products of the expected molecular weight up to about 200000, and there is no detectable accumulation of incomplete protein products . The efficient translation of RNA from two plant viruses (tobacco mosaic virus and cowpea mosaic virus) required heterologous tRNA.

Biochemistry, 1976 Jul 27, 15(15), 3307 - 14
Removal of histone H1 exposes a fifty base pair DNA segment between nucleosomes; Whitlock JP Jr et al.; Micrococcal nuclease has been used to prepare chromatin from HeLa cells and to probe the structure of HeLa chromatin under various ionic conditions and after the removal of chromatin proteins by salt extraction . The results suggest that (1) HeLa chromatin DNA exists as 150-160 base pair beads interspersed with 40-50 base pair bridges;(2) the bead and bridge conformation exists at physiologic salt concentrations; and (3) removal of histone H1 renders the 40-50 base pair bridge, but not the 150-160 base pair bead, more nuclease susceptible.

J Biol Chem, 1976 Jul 25, 251(14), 4330 - 5
A transition state analog of lysozyme catalysis prepared from the bacterial cell wall tetrasaccharide; Schindler M et al.; Treatment of the cell wall tetrasaccharide GlcNAcbeta(1 leads to 4)-MurNAc-beta(1 leads to 4)-GlcNAc-beta(1 leads to 4)-MurNAc with alkali resulted in the formation of the unsaturated tetrasaccharide GlcNAc-beta(1 leads to 4)-MurNAc-beta(1 leads to 4)-GlcNAc-beta(1 leads to 4)-delta2,3-2-acetamido-2-deoxy-D-glucoseen . The same compound was also formed by transglycosylation upon incubation of the unmodified tetrasaccharide with the unsaturated disaccharide GlcNAc-beta(1 leads to 4)-delta2,3-2-acetamido-2-deoxy-D-glucoseen (Tipper, D . J . (1968) Biochemistry 7, 1441-1449) and hen egg white lysozyme . The unsaturated tetrasaccharide was further characterized by paper electrophoresis, amino sugar analysis, and NMR . From NMR analysis it is concluded that the delta2,3-2-acetamido-2-deoxy-D-glucoseen at the reducing end of the unsaturated tetrasaccharide has a half-chair conformation . This conformation is similar to the one proposed for the sugar at subsite D in the lysozyme-substrate complex in the transition state . Addition of the unsaturated tetrasaccharide to a solution of hen egg white lysozyme quenched the fluorescence of the enzyme and shifted the fluorescence maximum to the blue, similar to the effect produced by the parent compound . The association constant of the unsaturated tetrasaccharide and lysozyme was measured at pH 6.0 and 24 degrees by spectrofluorimetry and microcalorimetry and found to be 1.45 X 10(5) M-1 and 2.5 X 10(5) M-1, respectively . The average value is 100 times higher than that found for the binding of unmodified tetrasaccharide to the enzyme under the same conditions . The unsaturated tetrasaccharide proved to be a better inhibitor of the lysis of Micrococcus luteus cells than the parent compound by a factor of 35 . These results support the hypothesis that the active site of the enzyme is constructed so as to bind the transition state for the reaction it catalyzes more firmly than the substrate itself.

Eur J Biochem, 1976 Jul 15, 66(3), 535 - 42
Isolation and properties of structured chromatin from Guerin ascites tumour and rat liver; Yaneva M et al.; The method proposed by Hancock for isolation of structured chromatin from tissue culture cells is modified and used for isolation of chromatin from Guerin ascites tumour and rat liver . Micrococcal nuclease digestion patterns and thermal denaturation of these chromatins are studied and compared wiith those of chromatins prepared by precipitation and extraction with salts (salt chromatins) . In contrast to the multiphasic melting profiles and salt chromatins, the structured chromatins exhibit relatively homogeneous denaturation patterns under a variety of conditions, suggesting thhat their DNA is uniformly stabilized by histones and there are no free independently melting DNA stretches . Digestion of structure of the deoxyribonucleoprotein is intact . No discrete fragments are formed upon digestion of salt chromatin.

Eur J Biochem, 1976 Jul 15, 66(3), 579 - 82
The binding of glycoconjugates to human-milk D-galactosyltransferase; Prieels JP et al.; Through the use of affinity chromatography, a homogeneous preparation of human beta(1 leads to 4)-D-galactosyltransferase (the A protein of lactose synthase) was obtained . The specificity of this protein for glycoconjugates was studied in the presence and absence of human alpha-lactalbumin . A kinetic analysis of the transfer of D-galactose to N-acetyl-D-glucosamine and the beta(1 leads to 4) linked N-acetylglucosamine oligomers, suggested that the active site region of the enzyme contains more than one binding site for acceptor moleucles . Furthermore, experiments with Na-acetylglucosamine-beta(1 leads to4)-N-acetylmuramic-pentapeptide isolated from Micrococcus luteus indicated that the presence of a peptide chain does not enhance enzymic activity, as compared with the corresponding free disaccharide . Similar results were obtained using ovalbumin and the ovalbumin glycopeptide (which have similar apparent Km values for A protein) as galactose acceptors . In contrast to its ability to inhibit N-acetyllactosamine production, alpha-lactalbumin did not inhibit the transfer of D-galactose to the N-acetylglucosamine oligomers or the glycopeptides . Although alpha-lactalbumin can switch the specificity of A protein from N-acetyl-D-glucosamine to D-glucose resulting in the production of lactose, no transfer of galactose was observed to beta(1 leads to 4)-linked glycose oligomers or to a collagen glycopeptide, D-glycopyranosyl-alpha(1 leads to 2)-D-galactopyranosyloxy-beta(1 leads to 5)-lysine . IT therefore appears that alpha-lactalbumin can only modify human A protein for monosaccharide acceptors.

Nucleic Acids Res, 1976 Jul, 3(7), 1761 - 7
Persistence of the ten-nucleotide repeat in chromatin unfolded in urea, as revealed by digestion with deoxyribonuclease i; Yaneva M et al.; It is shown by enzymatic digestion of chromatin from rat liver or Guerin ascites tumour (GAT) that treatments, which abolish the 180 base pair repeat, as revealed by digestion with micrococcal nuclease (shearing in salt solutions of medium ionic strength, sonication, fixation with formaldehyde in the presence of 5 M urea), have little effect on the 10 nucleotide repeat, observed in deoxyribonuclease I digests.

Mol Biol Rep, 1976 Jul, 2(6), 479 - 86
Distribution of globin genes in chicken reticulocyte chromatin fractionated on urografin gradients; Willetts BC et al.; Buoyant density centrifugation in Urografin solutions resolved French Pressure Cell-sheared, and micrococcal nuclease-digested avian reticulocyte chromatin into a broad profile of two peaks . Hybridization experiments using a globin cDNA probe suggested minimal fractionation of transcriptionally active and inactive components with chromatin sheared at 6000 psi, while no evidence was obtained for any fractionation with chromatin sheared at lower or higher pressures, or with chromatin digested to various extents with micrococcal nuclease, despite a considerable spread of chromatin material across gradients.

Am J Dig Dis, 1976 Jul, 21(7), 547 - 52
The inhibition of lysozyme by bile acids; Vantrappen G et al.; The effect of bile acids on the bacteriolytic activity of lysozyme towards Micrococcus lysodeikticus was studied in vitro . All bile acids tested inhibited lysozyme activity . Conjugated bile acids were better inhibitors than their unconjugated homologs and sulfation resulted in still stronger inhibition . A study of UV-difference spectra of bile acid-lysozyme mixtures suggests that bile acids distort the tertiary structure of the enzyme . The inhibition-concentration curves of micelle-forming bile acids were bell-shaped, and peak inhibition was apparently related to the critical micellar concentration . The inhibition-concentration curves of sulfated bile acids, which do not form micelles, are characterized by a plateau of maximal inhibition . A mechanism of lysozyme activation by bile acid micelles is proposed . Our results illustrate the complex interactions between antibacterial compounds in the gut . As bile acids are known to inhibit lipase activity as well, these studies suggest that bile acids may have an important influence on intestinal enzyme activity in general.

J Bacteriol, 1976 Jul, 127(1), 319 - 26
Amidase activity involved in peptidoglycan biosynthesis in membranes of Micrococcus luteus (sodonensis); Jensen SE et al.; Membrane suspensions prepared from Micrococcus luteus (sodonensis) in both the exponential and stationary phases of growth contained a transglycosidase activity capable of synthesizing linear peptidoglycan . Exponential-phase membranes also contained an N-acetylmuramyl-L-alanine amidase activity which degraded the peptidoglycan as it was formed . The product of this amidase was purified and found to be free pentapeptide . The amidase was specific for peptidoglycan and could not attack lower-molecular-weight substrates even though the susceptible bond was present . Crude cell wall preparations isolated from exponential-phase cells also contained high levels of amidase . This cell wall-bound amidase would preferentially degrade in vitro-synthesized peptidoglycan over its own cell wall . Amidase activity could be solubilized from both cell walls and membranes by Triton X-100 treatment, butanol extraction, or LiCl extraction . Both membrane- and cell wall-derived amidases, solubilized by LiCl extraction, appeared to be of high molecular weight (greater than 150,000) . Once solubilized, these wall- and membrane-derived amidases could attack the cross-bridged peptidoglycan of purified native cell walls, whereas bound amidases could not.

Nucleic Acids Res, 1976 Jul, 3(7), 1659 - 70
Control of RNA synthesis by chromatin proteins; Cedar H et al.; The effect of chromatin proteins on template activity has been studied . Using both E . coli RNA polymerase and calf thymmus polymerase B we have measured the number of initiation sites on chromatin and various histone-DNA complexes . Chromatin can be reconstituted with histone proteins alone and this complex is still a restricted template for RNA synthesis . The removal of histone f1 causes a large increase in the template activity . Chromatin is then treated with Micrococcal nuclease and the DNA fragments protected from nuclease attack ("covered DNA") are isolated . Alternatively, the chromatin is titrated with poly-D-lysine, and by successive treatment with Pronase and nuclease, the DNA regions accessible to polylysine are isolated ("open DNA") . Both fractions were tested for template activity . It was found that RNA polymerase initiation sites are distributed equally in open and covered region DNA.

Cell, 1976 Jul, 8(3), 357 - 63
Nucleosome structure in Aspergillus nidulans; Morris NR; The structure of chromatin from Aspergillus nidulans was studied using micrococcal nuclease and DNAase I . Limited digestion with micrococcal nuclease revealed a nucleosomal repeat of 154 base pairs for Aspergillus and 198 base pairs for rat liver . With more extensive digestion, both types of chromatin gave a similar quasi-limit product with a prominent fragment at 140 base pairs . The similarity of the two limit digests suggests that the structure of the 140 base pair nucleosome core is conserved . This implies that the difference in nucleosome repeat lengths between Aspergillus and rat liver is caused by a difference in the length of the DNA between two nucleosome cores . Digestion of Aspergillus chromatin with DNAase I produced a pattern of single-stranded fragments at intervals of 10 bases which was similar to that produced from rat liver chromatin.

J Bacteriol, 1976 Jul, 127(1), 309 - 18
Peptidoglycan biosynthesis in Micrococcus luteus (sodonensis): transglycosidase and phosphodiesterase activities in membrane preparations; Jensen SE et al.; Two enzyme activities involved in the biosynthesis of peptidoglycan in Micrococcus luteus (sodonensis), a transglycosidase and a phosphodiesterase, have been demonstrated in isolated membrane preparations . The transglycosidase activity promotes the in vitro synthesis of an uncross-bridged peptidoglycan that is completely susceptible to lysozyme . This in vitro-synthesized peptidoglycan consists of 76% "soluble" and 24% "insoluble" material . The soluble peptidoglycan is primarily a single low-molecular-weight species of approximately 20 disaccharide peptide units . "Insoluble" peptidoglycan, which likely represents newly synthesized material incorporated into an existing cell wall, was solubilized by butanol extraction, and the two were compared . The phosphodiesterase activity demonstrated in this system cleaves uridine diphosphate-N-acetylmuramyl-L-alanyl-D-isoglutamyl-L-lysyl-D-alanyl-D-alanine to yield N-acetylmuramyl-L-alanyl-D-isoglutamyl-L-lysyl-D-alanyl-D-alanine plus uridine 5'-monophosphate plus inorganic phosphate . This phosphodiesterase activity, not detected under normal transglycosidase assay conditions, is a recycling mechanism and acts indirectly through formation and subsequent cleavage of a lipid-linked intermediate.

Eur J Biochem, 1976 Jun 15, 66(1), 43 - 7
Activation parameters of the adenosine triphosphatase of Micrococcus lysodeikticus . A comparison of the soluble and membrane-bound forms of the enzyme; Ayala J et al.; The Arrhenius plots for the membrane-bound ATPase and its soluble form purified from Micrococcus lysodeikticus, presented discontinuities near 30 degrees C at pH 7.5 . Glycerol-containing lipids were not responsible for these discontinuities . The values of the enthalpies of activation were 12 (soluble) and 22 (membrane-bound) kcal/mol (50.2 and 92.0 kJ/mol) above 30 degrees C and 42 (soluble) and 29 (membrane-bound) kcal/mol (175.7 and 121.3 kJ/mol) below that temperature . The results suggested that both molecular forms of the ATPase were able to adopt at least two different structures, above and below the critical temperature . Of the two, only the high-temperature structure seemed to be enzymically active . In the case of lipid-dependent ATPases, such as the Escherichia coli enzyme, the transition between both enzyme structures probably occurred with simultaneous "melting" of their lipid microenvironment.

Biochim Biophys Acta, 1976 Jun 4, 436(1), 183 - 9
Micrococcus lysodeikticus membrane ATPase . Effect of trypsin on stimulation of a purified form of the enzyme and idenfification of its natural inhibitor; Carreira J et al.; A soluble purified form of Micrococcus lysodeikticus ATPase (form BAT, from strain B, active, trypsin-stimulated) was stimulated 100% by trypsin and this stimulation was inhibited by preincubation of the protease with phenyl methyl sulphonylfluoride . This form of the enzyme was also stimulated 125-150% by filtration on Sephadex G-200 . Analysis by sodium dodecyl sulphate-gel electrophoresis showed that stimulation of this form of M . lysodeikticus ATPase was always accompanied by the disappearance of a subunit of mol . wt . 25000 (epsilon subunit) . It suggests that this subunit is the natural inhibitor of M . lysodeikticus ATPase . In the case of ATPase stimulation by trypsin, a partial and limited degradation of the alpha subunit was also observed . The interaction between the epsilon subunit and the rest of the ATPase complex was reversibly affected by pH, suggesting its non-covalent nature.

Cancer Res, 1976 Jun, 36(6), 2073 - 9
Nonrandom nature of in vivo methylation of dimethylnitrosamine and the subsequent removal of methylated products from rat liver chromatin DNA; Ramanathan R et al.; This investigation was designed to study whether methylation of liver chromatin DNA by dimethylnitrosamine (DMN) and the subsequent in vivo removal of DNA-bound methylated products are random . Liver chromatin DNA was fractionated into nuclease-digestible and nondigestible material 4 hr following the administration of {3H}DMN (0.5 mg/250 muCi/100 g body weight) . Digestion of such methylated liver chromatin with pancreatic DNase I or micrococcal nuclease and analysis of nuclease-digested acid-soluble products revealed a discrepancy between the radioactivity released (72%) and the nucleotides released (50%) as measured by the absorbance at 260 nm . This discrepancy disappeared, and the rate and extent of release of both the radioactivity and the absorbance at 260 nm were identical when the total purified DNA isolated from methylated chromatin was used as the substrate instead of chromatin DNA in the nuclease reaction . These results, together with the fact that guanine contents of the DNA of the two fractions of the chromatin isolated by nuclease digestion were identical, suggest that methylation of the nuclease-accessible region of hepatic chromatin DNA is relatively greater than that of the inaccessible region . The study of the removal of methylated products in the accessible region of the chromatin DNA further reveals that, of the methylated products present at 4 hr, 62% is lost by 3 days, 87% is lost by 1 week and 94% is lost by 2 weeks . However, loss from the nuclease-inaccessible region of chromatin DNA is only 27% by 3 days, 49% by 1 week, and 86% by 2 weeks, thereby suggesting that the removal of methylated products from this region of chromatin DNA is relatively slower compared with that from the nuclease-accessible region of chromatin-DNA . The results of this study thus indicated (a) an increased methylation and faster rate of removal of DMN-induced methylated products in nuclease-accessible regions of chromatin DNA and (b) decreased methylation and slower rate of removal from the nuclease-inaccessible regions of chromatin DNA . It is concluded that the distribution and removal of DMN-induced methylated products in liver chromatin DNA is nonrandom as measured by this technique.

Proc Natl Acad Sci U S A, 1976 Jun, 73(6), 1897 - 901
Solenoidal model for superstructure in chromatin; Finch JT et al.; Chromatin prepared by brief digestion of nuclei with micrococcal nuclease, and extracted in 0.2 mM EDTA, appears in the electron microscope as filaments of about 100 A diameter which coil loosely . In 0.2 mM Mg++ these "nucleofilaments" condense into a supercoil or solenoidal structure of pitch about 110 A corresponding to the diameter of a nucleofilament . It is proposed that the x-ray reflections at orders of 110 A observed in chromatin originate in the spacing between turns of the solenoid rather than that between nucleosomes along the nucleofilament . The solenoidal structure appears to need histone H1 for its stabilization . Under certain conditions, isolated nucleosomes can also aggregate into a similar structure . The solenoidal structure can be correlated with the "thread" of diameter about 300 A observed by other workers in nuclei.

Biochim Biophys Acta, 1976 May 13, 429(3), 1020 - 8
Me2+-(13 S) ATPase from Micrococcus sp . ATCC 398E . The effect of trypsin on the purified enzyme; Hockel M et al.; By trypsin treatment of highly purified ATPase (EC 3.6.1.3) from Micrococcus sp . ATCC 398E, two enzyme modifications have been obtained . (i) ATPase Ta, which has about the same activity as untreated ATPase . (ii) A protein complex Ti, which lacks ATPase activity, but nevertheless binds ATP as shown by affinity chromatography . Trypsin primarily shortens the alpha-chains of the "native" enzyme to alpha-chains and removes the gamma-subunit, thus yielding ATPase Ta . The formation of the protein complex Ti appears to be due to additional cleavage of one alpha-chain into at least two more fractions.

J Bacteriol, 1976 May, 126(2), 587 - 92
Repair of ultraviolet light-induced damage in Micrococcus radiophilus, an extremely resistant microorganism; Lavin MF et al.; Repair of ultraviolet radiation damage was examined in an extremely radioresistant organism, Micrococcus radiophilus . Measurement of the number of thymine-containing dimers formed as a function of ultraviolet dose suggests that the ability of this organism to withstand high doses of ultraviolet radiation (20,000 ergs/mm2) is not related to protective screening by pigments . M . radiophilus carries out a rapid excision of thymine dimers at doses of ultraviolet light up to 10,000 ergs/mm2 . Synthesis of deoxyribonucleic acid is reduced after irradiation, but after removal of photodamage the rate approaches that in unirradiated cells . A comparison is drawn with Micrococcus luteus and M . radiodurans . We conclude that the extremely high resistance to ultraviolet irradiation in M . radiophilus is at least partly due to the presence of an efficient excision repair system.

Cell, 1976 May, 8(1), 59 - 64
Cesium chloride gradients of chromatin after treatment with micrococcal nuclease; Doenecke D; Cesium chloride equilibrium density centrifugation shows that treatment of rat liver nuclei with low concentrations of micrococcal nuclease for extremely short periods of time results in the appearance of chromatin fractions of low protein/DNA ratio and even free DNA . The DNA of these chromatin fractions is shorter than the DNA moiety of one chromatin subunit . The amount of high buoyant density material is decreased with increasing digestion time . We conclude that this material belongs to the minor chromatin fraction which is not organized according to the subunit model.

Cell, 1976 May, 8(1), 19 - 31
Small RNA species of the HeLa cell: metabolism and subcellular localization; Zieve G et al.; The small molecular weight RNAs of the HeLa cell have been located in specific subcellular fractions . SnA is located in the nucleolus and is partially bonded to nucleolar 28S RNA . SnD, the most abundant of the small nuclear RNAs, is partially released from the nucleus when the nuclear preparation is briefly warmed . SnF is released from the nuclei when chromatin is digested with the micrococcal nuclease and not when pancreatic DNAase is used . The remainder of the small nuclear species remain in the nucleus following the digestion of chromatin and are concluded to be elements of the "nuclear skeleton." SnK is found predominantly in the cytoplasm, but migrates quantitatively to the nuclear fraction in the presence of high levels of actinomycin D . ScL is totally cytoplasmic and is partially bound to cell membranes . It is the 7S RNA found in oncornavirus virions . All the small nuclear RNAs appear initially in the cytoplasmic fraction before fixation in the nucleus . Two short-lived cytoplasmic species behave kinetically as precursors to the stable nuclear RNAs.

Nature, 1976 Apr 8, 260(5551), 495 - 500
Genomic transcriptional activity and the structure of chromatin; Reeves R et al.; Nucleic acid hybridisation has shown that micrococcal nuclease-derived chromatin subunits from the cells of Xenopus laevis contain fragments of ribosomal 28S, 18S and 5S RNAS within the population of 200 base-pair pieces of DNA . Subunits from cultured embryonic cells actively transcribing ribosomal RNA contain only 70-74% of the cistrons present in undigested wild-type DNA, while subunits from adult erythrocytes not active in RNA transcription contain close to 90% of the ribosomal cistrons in native chromatin.

Biochim Biophys Acta, 1976 Apr 8, 429(2), 331 - 41
Mechanism of action of putrescine oxidase . Binding characteristics of the active site of putrescine oxidase from Micrococcus rubens; Swain WF et al.; Putrescine oxidase (EC 1.4.3.4), putrescine: oxygen oxidoreductase (deaminating) (flavin containing), has been found to form complexes with a variety of amines . With few exceptions these compounds competitively inhibit putrescine oxidation and also perturb the visible absorption spectrum of the enzyme (i.e., the spectrum due to FAD) . Inhibition constants are reported for a number of amines; the presence of a cationic amino group in the inhibitors appears to be the structural feature essential for competitive inhibition . Inhibition constants for amino acids are larger than those for the analogous simple amines and the inhibition constants for alkyl mono- and diamines in a homologous series are inversely related to the length of the hydrocarbon chain . Amines containing unsaturated and aromatic substituents yield relatively low inhibition constants . The spectral changes observed upon complex formation are interpreted as indicating a less polar environment for FAD in the enzyme-inhibitor complex than in the uncomplexed enzyme . On the basis of the enzyme's substrate specificity and comparisons among inhibitor structures and the corresponding inhibition constants, a schematic model of the enzyme's active site is proposed.

Cell Tissue Res, 1976 Apr 2, 167(3), 407 - 24
Nucleolar DNA in oocytes of Salmo irideus (Gibbons); Vlad M; The amplification of ribosomal genes has been studied in oocytes from Salmo irideus . In situ nucleic acid hybridization showed that the synthesis of nucleolar DNA begins in oogonium and proceeds slowly through leptotene and zygotene when a small amount of extrachromosomal nucleolar DNA is produced . In early pachytene there is a rapid build-up of nucleolar DNA demonstrable by rapid incorporation of tritiated thymidine . Synthesis stops completely in early diplotene when nucleolar DNA becomes dispersed over the inner surface of the nuclear envelope in the form of small Feulgen-positive granules . Photometric measurements of Feulgen stained nuclei showed that the final amount of amplified nucleolar DNA synthesized in each oocyte is approximately 20 mug . The amplified DNA does not form a heterochromatic mass . The buoyant density of the amplified nucleolar DNA calculated from analytical centrifuge tracings in relation to DNA from Micrococcus luteus (rho = 1.731 g cm-3) is 1.715 g cm-3 and corresponds to a G+C content of 57% . There are indications that the buoyant density of the somatic nucleolar DNA is lower than that of amplified nucleolar DNA . Similarities and differences between ribosomal gene amplifications in oocytes of Salmo irideus and the corresponding process in Xenopus are discussed.

Arch Microbiol, 1976 Apr 1, 107(3), 313 - 20
The fine structure of Micrococcus radiophilus and Micrococcus radioproteolyticus; Sleytr UB et al.; The radiation resistant bacteria Micrococcus radiophilus and M . radioproteolyticus were studied by thin sectioning and freez-etching techniques and the two species were found to be similar in the fine structure . The only significant difference was in the appearance of the surfaces of the cell walls in freeze-etched preparations . Since the two species, together with M . radiodurans, possess a unique cell wall structure and a cell wall peptidoglycan, which is different from that of other micrococci and Gram-positive cocci, it is recommended that they be reclassified into a new genus.

Carbohydr Res, 1976 Apr, 47(2), 245 - 60
The chemical structure of a fragment of Micrococcus lysodeikticus cell-wall; Din NU et al.; A fragment of Micrococcus lysodeikticus cell-wall obtained by cetylpyridinium recipitation from the nondialyzable portion of the degradation products of egg-white lysozyme was studied by the periodate oxidation and methylation procedures . The fragment consists of a polysaccharide chain composed of about 40 repeating (1 leads to 4)-O-(2-acetamido-2-deoxy-beta-D-mannopyranosyluronic acid)-(1 leads to 6)-O-(alpha-D-glucopyranosyl) residues with D-glucopyranosyl residues at both ends . The alpha-D-glucopyranose residue at the reducing end is linked to a phosphate group that is also linked to C-6 of a 2-acetamido-3-O-(D-1-carboxyethyl)-2-deoxy-beta-D-glucopyranosyl residue of a peptidoglycan chain composed of four repeating (1 leads to 4)-O-{2-acetamido-3-O-(D-1-carboxyethyl)-2-deoxy-beta-D-glucopyranosyl} residues . The peptidoglycan chain has, as nonreducing group, a 2-acetamido-2-deoxy-beta-D-glucopyranosyl group, and, as reducing residue, a 2-acetamido-3-O-(D-1-carboxytheyl)-2-deoxy-beta-D-glucose residue.

J Gen Microbiol, 1976 Apr, 93(2), 272 - 7
Differentiation of Micrococcus luteus and Micrococcus varians on the basis of catalase isoenzymes; Fox RH; Crude extracts prepared from four Micrococcus varians strains, 11 M . luteus strains and four laboratory isolates subsequently classified with M . luteus were assayed for catalase activity following electrophoresis on polyacrylamide gels . The enzyme patterns produced from the M . varians strains exhibited three catalase isoenzymes which were distinguished into two types of patterns depending upon the location of the major band . The extracts from all the M . luteus strains produced the same pattern, composed of two catalase isoenzymes of similar electrophoretic mobility . For both species the isoenzyme patterns agreed with the differentiation based on biochemical properties . The catalase activity activity staining method was shown to be a restricted yet reliable assay in the intrageneric but not intraspecies differentiation of yellow-pigmented micrococci.

J Gen Microbiol, 1976 Apr, 93(2), 251 - 8
The rate of recombination repair and its relationship to the radiation-induced delay in DNA synthesis in Micrococcus radiodurans; Moseley BE et al.; The measurement of the time at which normal colony-forming ability returns in irradiated cultures of Micrococcus radiodurans tsI held at 30 degrees C can be used to estimate the time of completion of recombination repair . By comparing the times to complete such repair in populations given increasing radiation doses it is possible to calculate the rate of recombination repair . The rate was independent of the radiation dose; recombination could repair in one minute the damage caused either by 1-2 krad gamma radiation or 4 X 10(-6) J mm-2 u.v . radiation . The time taken for the normal rate of DNA synthesis to return in irradiated M . radiodurans tsI was measured under conditions identical to those used to measure recombination repair . The delay in DNA synthesis was 1-0 min per 1-2 krad gamma radiation and 1-0 min per 5-6 X 10(-6) J mm-2 u.v . radiation . The data suggest that the normal rate of DNA synthesis resumes immediately after the completion of recombination repair of gamma-induced damage, but before the completion of recombination repair of u.v.-induced damage . It is postulated that cell death at the lethal dose of u.v . radiation is caused by a second round of replication of DNA which is still being repaired by recombination.

Radiat Environ Biophys, 1976 Mar 30, 13(1), 13 - 8
Response of membrane-bound ATPase of Micrococcus luteus to heat and ultraviolet light; Volotovskij J et al.; It is shown that the properties of ATPase (EC 3.6.1.3) of Micrococcus luteus depend only to some extent on the state of the membrane to which it is attached . Its interaction with the membrane appears to be largely controlled by polar forces . It is shown, however, that the UV-sensitivity of the membrane-bound ATPase is also significantly influenced by the state of membrane lipids.

Biochemistry, 1976 Mar 9, 15(5), 1005 - 15
Synthesis and biological activity of pyrazolo{3,4,-d}pyrimidine nucleosides and nucleotides related to tubercidin, toyocamycin, and sangivamycin; Hecht SM et al.; The 6-aza analogues of toyocamycin and sangivamycin were prepared as potential cytotoxic agents . The toyocamycin analogue (4-amino-1-(beta-D-ribofuranosyl)pyrazolo{3,4-d}pyrimidine-3-carbonitrile) could not be obtained directly from its O-acetylated precursor but was accessible via 4-amino-1-(beta-D-ribofuranosyl)pyrazolo{3,4-d}pyrimidine-3-thiocarboxamide . The identity of the nitrile was verified by its ultraviolet, infrared, and mass spectra, and by its conversion to the corresponding 3-carboxamide and thiocarboxamide when treated with water or hydrogen sulfide, respectively . Bioassay of the synthetic compounds in comparison with 4-amino-1-(beta-D-ribofuranosyl)pyrazolo{3,4-d}pyrimidine (6-azatubercidin) and 4-amino-2-(beta-D-ribofuranosyl)pyrazolo{3,4-d}pyrimidine revealed that the 3-thiocarboxamido derivative was more cytotoxic to the growth of mouse fibroblasts than 6-azatubercidin, effecting killing of 3T6 cells at less than or equal to 1 mug/ml . 4-Amino-1-(beta-D-ribofuranosyl)pyrazolo{3,4-d}pyrimidine (but not its 2-ribofuranosyl isomer) was shown to act as a substrate for adenosine deaminase from calf intestinal mucosa with an apparent Km of 125 (vs . 20 for adenosine) and the corresponding 5'-diphosphate of 6-azatubercidin was polymerized by polynucleotide phosphorylase (Micrococcus luteus) in the presence of Mn2+ to afford a homopolymer and copolymers with adenosine . The copolymers directed the binding of {3H}lysyl-tRNA to the A-site of ribosomes from Escherichia coli, but could not be used for the synthesis of polylsine in a cellfree system . The copolymer consiting of adenosine and 6-azatubercidin in a 2:1 ratio was found to form a 1:1 complex with poly(uridylic acid) at 4degreesC.

Vet Med (Praha), 1976 Mar, 21(3), 175 - 85
{Residues of chloramphenicol in the calf organism following parenteral administration of the Czechoslovak preparation Chronicin inj}; Malikova M et al.; Using two biological methods the chloramphenicol content in various tissues of 11 calves aged 3--18 days was determined after a single-dose therapeutical administration of the Czechoslovak preparation of Chronicin inj . in the quantity of 12 mg kg-1 body mass . Of four test strains, solely Micrococcus flavus (ATCC 10240) strain proved suitable . Chloramphenicol was quantitatively determined by reading from transformed standard curves . An evalua tion of the two approximately equally sensitive methods yielded the following results: three days after the injection all calves were positive, at 5 and 10 days, one of three calves in each group was negativ similarly to both calves slaughtered 15 days post injection . The residues appeared most frequently in the liver, at the site of injection, and in the fore and hind musculature . Maximum detectable concentrations were recorded in the liver . Culinary and technological treatment of positive meat and liver samples revealed that 15 minutes' boiling and 30 minutes' roasting destroyed the microbiologically active chloramphenicol residues in the samples . Neither deep freezing nor salting was sufficient for residue inactivation, although in some samples a decrease in biological chloramphenicol activity by circa 20--30% was recorded . a preslaughter withdrawal time of 15 days is recommended.

Vet Med (Praha), 1976 Mar, 21(3), 161 - 6
{Persistance of penicillin residues in the calf organism after parenteral therapeutical administration of the preparation penicillin G, procaine inj ad usum vet}; Habrda J et al.; By means of two biological diffusion methods a penicillin content in various calf tissues was determined . For the injections PROKAIN Penicillin G Spofa, inj . adusum vet., was used in a single dose of 25 000 i . u . kg-1 body mass . For the tests three collection strains -- B . subtilis (ATCC 6633), Sarcina lutea (ATCC 9341), and Micrococcus flavus (ATCC 10240) were used . A quantitative determination of penicillin in the samples was accomplished by reading from the standard curves . Sensitivities of the two methods were approximately the same; Micrococcus flavus proved most suitable of the microorganisms employed . At 2, 3, 5 and 20 post-treatment days both test animals were positive; at 10 days three out of four calves examined were positive, whereas at 15 days two out of three calves examined were positive . The residues were most frequently found in the liver, kidney and at the injection sites . Maximum detectable concentrations were at the injections sites, minimum ones in the bone marrow . In the musculature (noninjection site) a small quantity of penicillin was found up to 20 days after the application . Current culinary and technological treatment of positive meat and liver samples did not always suffice for complete inactivation of the penicillin residues . For the tested preparation, a preslaughter withdrawal time of 30 days is recommended.

Infect Immun, 1976 Mar, 13(3), 704 - 11
Virulent Treponema pallidum: aerobe or anaerobe; Baseman JB et al.; Substrate degradation and protein synthesis served as indicators of metabolism in virulent Treponema pallidum . Opitmal metabolic activity in these spirochetes was observed at 10 to 20% O2 concentrations, with markedly reduced activity at higher or lower O2 levels or under anaerobiosis; alternate functioning electron acceptors that might substitute for O2 were not found . Carbon monoxide and cyanide at concentrations that inactivate cytochrome oxidase were not effective metabolic poisons for T . pallidum, although Micrococcus lutea, a strict aerobe with cytochrome-dependent respiration, was inhibited under similar experimental conditions . Motility of virulent T . pallidum was vigorous in the presence of O2 and sluggish or inhibited in its absence, reinforcing the role of O2 in T . pallidum metabolism.

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