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Carlos Hardisson - One of the best experts on this subject based on the ideXlab platform.

  • Nitrogen starvation‐induced glycogen synthesis depends on the developmental stage of Streptomyces antibioticus mycelium
    FEMS Microbiology Letters, 2006
    Co-Authors: Elisa M. Miguélez, Monica Fernandez, Carlos Hardisson
    Abstract:

    Experiments carried out to examine the ability of Streptomyces antibioticus to accumulate glycogen, when starved for nitrogen at different times during growth, revealed that nitrogen-starved hyphae, irrespective of the developmental time at which they were starved, accumulated glycogen only when they had acquired ultrastructural features typical of stationary-phase cultures. Oleandomycin production and trehalose accumulation were also examined during the starvation period. The observed pattern of oleandomycin production resembles that of glycogen. However, trehalose accumulates with no lag period after nitrogen starvation, regardless of the developmental phase of growth.

  • nitrogen starvation induced glycogen synthesis depends on the developmental stage of Streptomyces antibioticus mycelium
    Fems Microbiology Letters, 1997
    Co-Authors: Elisa M. Miguélez, Monica Fernandez, Carlos Hardisson
    Abstract:

    Experiments carried out to examine the ability of Streptomyces antibioticus to accumulate glycogen, when starved for nitrogen at different times during growth, revealed that nitrogen-starved hyphae, irrespective of the developmental time at which they were starved, accumulated glycogen only when they had acquired ultrastructural features typical of stationary-phase cultures. Oleandomycin production and trehalose accumulation were also examined during the starvation period. The observed pattern of oleandomycin production resembles that of glycogen. However, trehalose accumulates with no lag period after nitrogen starvation, regardless of the developmental phase of growth.

  • Structural changes induced by glycine on Streptomyces antibioticus
    FEMS microbiology letters, 1994
    Co-Authors: M.r. Rodicio, Carlos Hardisson
    Abstract:

    Germination and vegetative growth of Streptomyces antibioticus in liquid medium with different concentrations of glycine was examined. Both processes proved to be sensitive to the amino acid, being inhibited by 5 and 2.5% glycine, respectively. At concentrations of 5% or more, lysis of the vegetative mycelium occurred. Subinhibitory concentrations of glycine induced structural changes on germinating spores. These included an increase in the number of germ tubes produced by spore, in relation to the control. Moreover, soon after outgrowth the tubes bifurcate, giving rise to germinated spores with a characteristic aspect, and anomalous formation of cross-walls that appear both within the spores and in the newly formed germinative tubes, at or close to the region of outgrowth. The branching effect of glycine was also observed during vegetative growth of S. antibioticus.

  • Synchronous germination of Streptomyces antibioticus spores : tool for the analysis of hyphal growth in liquid cultures
    FEMS microbiology letters, 1993
    Co-Authors: Elisa M. Miguélez, Carlos Hardisson, Cruz Martín, Manuel B. Manzanal
    Abstract:

    We have devised a method for obtaining synchronous and dispersed growth of Streptomyces antibioticus in liquid cultures. After ultrasonic treatment, most of the spores germinated at the same time, yielding hyphae very similar in length. Dispersed growth was achieved in media without Ca2+ and in which the levels of Fe2+ and Mg2+ were carefully controlled. Studies on the kinetics of growth carried out with synchronous cultures of young hyphae revealed a multiphasic pattern of hyphal elongation, with successive periods of linear growth and changes in growth rate at defined intervals.

  • Research letterSynchronous germination of Streptomyces antibioticus spores: Tool for the analysis of hyphal growth in liquid cultures
    Fems Microbiology Letters, 1993
    Co-Authors: Elisa M. Miguélez, Carlos Hardisson, Cruz Martín, Manuel B. Manzanal
    Abstract:

    We have devised a method for obtaining synchronous and dispersed growth of Streptomyces antibioticus in liquid cultures. After ultrasonic treatment, most of the spores germinated at the same time, yielding hyphae very similar in length. Dispersed growth was achieved in media without Ca2+ and in which the levels of Fe2+ and Mg2+ were carefully controlled. Studies on the kinetics of growth carried out with synchronous cultures of young hyphae revealed a multiphasic pattern of hyphal elongation, with successive periods of linear growth and changes in growth rate at defined intervals.

Elisa M. Miguélez - One of the best experts on this subject based on the ideXlab platform.

Jesús Sánchez - One of the best experts on this subject based on the ideXlab platform.

  • A death round affecting a young compartmentalized mycelium precedes aerial mycelium dismantling in confluent surface cultures of Streptomyces antibioticus.
    Microbiology, 2005
    Co-Authors: Angel Manteca, Marisol Fernández, Jesús Sánchez
    Abstract:

    Development-associated cell-death processes were investigated in detail during the growth and differentiation of Streptomyces antibioticus ATCC 11891 on confluent surface cultures, by using fluorescent viability probes, membrane and activity fluorescence indicators, and electron microscopy analysis. A previously unsuspected complexity was revealed, namely the presence of a very young compartmentalized mycelium that dies following an orderly pattern, leaving alternating live and dead segments in the same hypha. This death round is followed by the growth of a second mycelium which develops rapidly from the live segments of the first mycelium and dies massively in a second death round, which extends over the phases of aerial mycelium formation and sporulation.

  • Cytological and biochemical evidence for an early cell dismantling event in surface cultures of Streptomyces antibioticus.
    Research in microbiology, 2005
    Co-Authors: Angel Manteca, Marisol Fernández, Jesús Sánchez
    Abstract:

    A process of programmed cell death taking place late in the aerial mycelium was previously reported in surface cultures of Streptomyces antibioticus ATCC11891. In this study, we present evidence for the occurrence of a similar process taking place early in the vegetative mycelium of surface cultures of the same strain. Several indicators, such as cell wall and membrane disruption, DNA degradation and release of the cytoplasmic content into the exocellular medium, support the existence of active, highly regulated cell suicide involving specific enzymes. Calcium-dependent proteolytic activation of a precursor of nucleases and the nucleolytic formation of a ladder of chromosomal bands are conspicuous events associated with the initiation of the death process.

  • Cloning and characterization of a Streptomyces antibioticus ATCC11891 cyclophilin related to Gram negative bacteria cyclophilins.
    FEBS Letters, 2004
    Co-Authors: Angel Manteca, Thilo Kamphausen, Jörg Fanghänel, Gunter Fischer, Jesús Sánchez
    Abstract:

    Abstract Cyclophilins are folding helper enzymes and represent a family of the enzyme class of peptidyl-prolyl cis–trans isomerases. Here, we report the molecular cloning and biochemical characterization of San Cyp18, an 18-kDa cyclophilin from Streptomyces antibioticus ATCC11891 located in the cytoplasm and constitutively expressed during development. Amino acid sequence analysis revealed a much higher homology to cyclophilins from Gram negative bacteria than to known cyclophilins from Streptomyces or other Gram positive bacteria. San Cyp18 is inhibited weakly by CsA, with a K i value of 21 μM, similar to cyclophilins from Gram negative bacteria. However, this value is more than 20-fold higher than the K i values reported for cyclophilins from other Gram positive bacteria, which makes San Cyp18 unique within this group. The presence of San Cyp18 in Streptomyces is likely due to horizontal gene transmission from Gram-negative bacteria to Streptomyces .

  • Interaction of the periplasmic dG-selective Streptomyces antibioticus nuclease with oligodeoxynucleotide substrates.
    Biochemistry, 1996
    Co-Authors: Santiago Cal, Rebeca G. Nicieza, Bernard A. Connolly, Jesús Sánchez
    Abstract:

    The interaction of a periplasmic nuclease, isolated from Streptomyces antibioticus, with several oligodeoxynucleotide substrates has been studied. Double-stranded oligonucleotides that contain sequences of four or more consecutive deoxyguanosine residues are preferentially hydrolyzed, with the strongest cutting site occurring at GGG↓G. The enzyme does not hydrolyze these sequences in single-stranded DNA. However the sequence selectivity of the nuclease is far from absolute. Other sequences can also be cut, albeit more poorly, and differences in cutting rates are observed for runs of dG bases that differ in their flanking sequences. An oligonucleotide, thirty-six bases in length, that contains a central run of five dG bases has been used to evaluate the importance of the individual deoxyguanosines in recognition and cleavage. With this oligonucleotide cutting takes place at GG▾G↓G▾G (↓, most prominent cut; ▾, less prominent cuts). The use of dG base analogues revealed that two bases, one and two steps remo...

  • A novel exocytoplasmic endonuclease from Streptomyces antibioticus.
    Biochemical Journal, 1995
    Co-Authors: Santiago Cal, C G De Los Reyes-gavilan, Jesús F. Aparicio, R G Nicieza, Jesús Sánchez
    Abstract:

    A new exocytoplasmic, nutritionally controlled endodeoxyribonuclease (EC 3.1.21.-) was purified to homogeneity from Streptomyces antibioticus. The enzyme showed an apparent molecular mass of 29 kDa (being active in the monomeric form) and a pI of approximately 7.8. The nuclease hydrolysed endonucleolytically double-stranded circular and linear DNA. The enzyme makes nicks in one strand of the DNA in G-rich regions, leaving either 5' or 3' short, single-stranded overhangs with 3'-hydroxy and 5'-phosphate termini. Breaks in the DNA occur when two nicks in opposite strands are close together. The enzyme had an optimum pH of 7.5 and an absolute requirement for bivalent cations and > or = 100 mM NaCl in the reaction buffer. Activity was greatly diminished in the presence of phosphate, Hg2+ or iodoacetate and was stimulated by dimethyl sulphoxide. Single-stranded DNA was a much poorer substrate than double-stranded DNA. The nuclease hydrolyses sequences of three or preferably more (dG).(dC) tracts in the DNA. The initial specificity shifts to other sequences (including sequences shorter than those initially hydrolysed) during the course of the reaction, giving the changing pattern of bands observed in agarose gels. 5-Methylcytosine-hemimethylated DNA is not hydrolysed by the nuclease. The properties of this novel enzyme suggest a relationship with class II restriction endonucleases and also with some eukaryotic nucleases.

George H. Jones - One of the best experts on this subject based on the ideXlab platform.

  • RNase III Is Required for Actinomycin Production in Streptomyces antibioticus
    Applied and environmental microbiology, 2013
    Co-Authors: Junghoon Lee, Marcha L. Gatewood, George H. Jones
    Abstract:

    Using insertional mutagenesis, we have disrupted the RNase III gene, rnc, of the actinomycin-producing streptomycete, Streptomyces antibioticus. Disruption was verified by Southern blotting. The resulting strain grows more vigorously than its parent on actinomycin production medium but produces significantly lower levels of actinomycin. Complementation of the rnc disruption with the wild-type rnc gene from S. antibioticus restored actinomycin production to nearly wild-type levels. Western blotting experiments demonstrated that the disruptant did not produce full-length or truncated forms of RNase III. Thus, as is the case in Streptomyces coelicolor, RNase III is required for antibiotic production in S. antibioticus. No differences in the chemical half-lives of bulk mRNA were observed in a comparison of the S. antibioticus rnc mutant and its parental strain.

  • Transcriptional analysis and regulation of the sigma-E gene of Streptomyces antibioticus.
    Biochimica et biophysica acta, 2001
    Co-Authors: Patricia Bralley, George H. Jones
    Abstract:

    We report here the mapping of the transcriptional start point and identification of the promoter for the sigE gene of Streptomyces antibioticus. Sequence analysis revealed a conserved genetic organization of five genes encompassing sigE in S. antibioticus and S. coelicolor. Upstream of sigE a number of direct repeats, while conserved in both species, are arranged differently. Gel shift analysis demonstrated binding of a component of both S. antibioticus and S. coelicolor crude protein extracts to a 30 bp sequence encompassing one repeat, the A-rich box. Deletion analysis in promoter probes showed that maximal activity of the S. antibioticus promoter depends upon the presence of the sequence surrounding the A-rich box, as well as the region further upstream carrying other direct repeats.

  • relA is required for actinomycin production in Streptomyces antibioticus.
    Journal of bacteriology, 1999
    Co-Authors: Shannan Hoyt, George H. Jones
    Abstract:

    The relA gene from Streptomyces antibioticus has been cloned and sequenced. The gene encodes a protein with an Mr of 93,653, which is 91% identical to the corresponding protein from Streptomyces coelicolor. Disruption of S. antibioticus relA produces a strain which grows significantly more slowly on actinomycin production medium than the wild type or a disruptant to which the intact relA gene was restored. Moreover, the disruptant was unable to accumulate ppGpp to the levels observed during the normal course of growth and actinomycin production in the wild type. The strain containing the disrupted relA gene did not produce actinomycin and contained significantly lower levels of the enzyme phenoxazinone synthase than the wild-type strain. Actinomycin synthetase I, a key enzyme in the actinomycin biosynthetic pathway, was undetectable in the relA disruptant. Growth of the disruptant on low-phosphate medium did not restore actinomycin production.

  • Sigma-E is required for the production of the antibiotic actinomycin in Streptomyces antibioticus.
    Molecular microbiology, 1997
    Co-Authors: George H. Jones, Mark S. B. Paget, Leony Chamberlin, Mark J. Buttner
    Abstract:

    The phsA gene encodes phenoxazinone synthase (PHS), which catalyses the penultimate step in the pathway for actinomycin biosynthesis in Streptomyces antibioticus. The phsA promoter strikingly resembles a putative Streptomyces s(E) cognate promoter, and purified Es(E) holoenzyme transcribed the phsA promoter in vitro. However, the phsA promoter was still active in an S. antibioticus sigE null mutant and the level of PHS activity was unaffected. Despite this, disruption of sigE blocked actinomycin production completely. The loss of actinomycin production correlated with a 10-fold decrease in the activity of actinomycin synthetase I, the enzyme which catalyses the activation of the precursor of the actinomycin chromophore.

  • Guanosine pentaphosphate synthetase from Streptomyces antibioticus is also a polynucleotide phosphorylase
    Journal of bacteriology, 1996
    Co-Authors: George H. Jones, M J Bibb
    Abstract:

    The gene for the enzyme guanosine pentaphosphate synthetase I (GPSI) from Streptomyces antibioticus has been cloned and sequenced. The cloned gene functioned as a template in the streptomycete coupled transcription-translation system and directed the synthesis of a protein with the properties expected for GPSI. Sequencing of the cloned gene identified an open reading frame of 740 amino acids whose amino terminal sequence corresponded to the N terminus of purified GPSI. The GPSI protein sequence was found to possess significant homology to polynucleotide phosphorylase from Escherichia coli. Indeed, like E. coli polynucleotide phosphorylase, purified GPSI was shown to catalyze the polymerization of ADP and the phosphorolysis of poly(A). However, the E. coli enzyme was unable to catalyze the synthesis of guanosine pentaphosphate under conditions in which GPSI was highly active in that reaction. Overexpression of the cloned gpsI gene in E. coli led to an increase in both polynucleotide phosphorylase and guanosine pentaphosphate synthetase activities in the cloning host. The polynucleotide phosphorylase activities of GPSI and of the E. coli enzyme were strongly inhibited by dCDP, but the pppGpp synthetase activity of GPSI was not inhibited and indeed was slightly stimulated by dCDP. These results strongly support the identity of GPSI as a bifunctional enzyme capable of both pppGpp synthesis and polynucleotide phosphorylase activities.

Manuel B. Manzanal - One of the best experts on this subject based on the ideXlab platform.