An Intracellular Endonuclease of <i>Bacillus subtilis</i> Specific for Single‐Stranded DNA

Ciarrocchi, Giovanni; Fortunato, Adriana; Cobianchi, Fabio; Falaschi, Arturo

doi:10.1111/j.1432-1033.1976.tb10043.x

Cited by 10 publications

(9 citation statements)

References 21 publications

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“…Some of the enzymes have been implicated in the process of recombination, e.g. an ATP-dependent DNAase (Chestukhin et al, 1972;Doly & Anagnostopoulos, 1976) and an endonuclease specific for single-stranded DNA (Ciarrocchi et al, 1976). It was reported that mutants that were inhibited in recombination also possessed lower activities of these enzymes.…”

Section: Discussionmentioning

confidence: 99%

“…Similarly the heat-activated endonuclease (Burke & Spizizen, 1977) can hydrolyse native or denatured DNA, but also does not degrade the DNA to acid-soluble material. Apart from the endonuclease specific for single-stranded DNA (Ciarrocchi et al, 1976), most of the remaining well-characterized DNAases of B. subtilis are exonucleases (Kerr et al, 1965;Okazaki et al, 1966;Kanamori et al, 1974).…”

Section: Discussionmentioning

confidence: 99%

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Purification and properties of a manganese-stimulated deoxyribonuclease produced during sporulation of Bacillus subtilis

Akrigg¹

1978

Biochemical Journal

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A DNAase (deoxyribonuclease) was isolated from culture supernatants of sporulating Bacillus subtilis 168. The purified enzyme migrated as a single band during polyacrylamide-gel electrophoresis. The enzyme differs from other DNAases of B. subtilis in molecular weight, metal-ion requirement and mode of action. The enzyme was inactive in the absence of metal ions, and exhibited optimum activity with 10 mM-Mn2+, although Mg2+, Cd2+ and Co2+ could also permit some activity. The pH optimum for the enzyme was pH 7.5, and it degraded linear-duplex DNA or closed-circular-duplex DNA to acid-soluble material. There was little or no activity on single-stranded DNA or rRNA. Sucrose-gradient analysis of the products of DNAase action on bacteriophage T7 DNA showed that endonucleolytic cleavage had occurred by the introduction of single-strand breaks in both strands of the duplex. The molecular weight of the enzyme was determined, by gel filtration on Sephadex G-75, to be 12000.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Purification and properties of a manganese-stimulated deoxyribonuclease produced during sporulation of Bacillus subtilis

Akrigg¹

1978

Biochemical Journal

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“…The moving terrestrial/aquatic transition creates a great variety of environmental conditions conducive to biodiversity, whereas during high water period primary productivity is weaker because of dilution, shorter residence time, and increased depth (Ciarrocchi et al, 1976;Scho ngart & Junk, 2007;Thomaz et al, 2007;Junk et al, 2012). During the flushing period, decreasing depth and degradation of the autogenic organic material pro-motes a second peak in primary productivity (Ciarrocchi et al, 1976;Alcântara et al, 2011). During low water, floodplains present a smaller water volume profoundly stirred and turbid and remain or not connected to the main channel (Tockner et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

Interannual hydrological variations and ecological phytoplankton patterns in Amazonian floodplain lakes

et al. 2018

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Amazonian aquatic environments are complex, and their interaction promotes heterogeneous environments that turn difficult the development of patterns to describe them. We evaluated if interannual variation in the physical-chemical structure and the phytoplankton community promote environmental and biological contrasted conditions between similar hydrological periods. Amazonian floodplain lakes have different environmental and biological responses in similar water periods due to the interannual variation. Phytoplankton community structure has differences between periods, but these differences do not necessary promote dissimilarities. Most of the phytoplankton species belong to the same functional groups. The composition of species and functional groups between sample units inside lakes is variable and may have or not significant differences in dissimilarity, but both periods are equally heterogeneous. Beta diversity has shown that the replacement of species and functional groups causes a great level of variation between sites, which maintain a high heterogeneity between periods. These variations have different responses for different scales turning a difficult task the interpretation of patterns for these environments. Hence, scale and interannual variability are factors that need to be carefully considered when setting standards to describe the ecological dynamics of floodplain lakes in the Amazonian system.

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“…Protoplasts were suspended in 3 ml of 0.01 M Tris-hydrochloride buffer (pH 7.5), 1 mM dithiothreitol, and 1 mM CaCl2 and sonicated for 5 s at 0°C. The DNase activity was assayed using methods previously described (3). DNA polymerase I (Pol I) activity, defined as thep-chloromercuribenzoate-insensitive fraction of the total DNA polymerase activity, was assayed by the method of Ciarrocchi et al (2).…”

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confidence: 99%

Bacillus subtilis deoxyribonuclease activity specific for single-stranded deoxyribonucleic acid: cellular site and variations during germination and sporulation

Cobianchi¹,

Attolini²,

Falaschi³

et al. 1980

J Bacteriol

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The endonuclease of Bacillus subtilis specific for single-stranded deoxyribonucleic acid is absent in spores, appears during germination only after the start of deoxyribonucleic acid synthesis, and is located almost exclusively in the periplasm.The main DNase of Bacillus subtilis that degrades single-stranded DNA can be fractionated into two forms which account for most of the total activity: a very high-molecular-weight endonuclease (greater than 5 x 106) and a lowmolecular-weight endonuclease (36,000) (3). The higher-molecular-weight form can be converted almost quantitatively and irreversibly into the small enzyme by mild proteolytic treatment (4). A role for this sort of enzyme in physiological processes can be inferred from the observation that a recombination-deficient mutant of B. subtilis (rec3O) (6) is reduced in this activity to approximately 13% of the wild-type level. The study of the cellular site of this enzyme is therefore relevant to its possible function in the handling of the incoming DNA, whether in transformation or in transduction. We have therefore studied whether protoplast formation releases the DNase in question into the medium, and we measured the level of this activity in the spore and at different times after spore activation.Cells (1.3 g) of B. subtilis SB202 hisB2 tyrAl trpC2 aroB2 were treated with lysozyme to destroy the cell wall and remove the soluble periplasmic fraction. In this way 80% of the total activity as measured by the acid solubilization assay was released (see Table 1). The remainder was extracted by subsequent osmotic shock and sonication of protoplasts. Scher and Dubnau also described a B. subtilis endonuclease activity localized in the protoplast supernatant, but this activity is specific for double-stranded DNA (7). The DNase specific for single-stranded DNA released by lysozyme (and therefore probably located in the periplasm) is fractionable into two molecular weight species, like the enzyme activity extracted by less specific treatment (whether alumina grinding or sonication) of whole cells. DNA polymerase I activity was monitored to show that internal enzymes are not released by the procedure used to obtain protoplasts of vegetative B. subtilis cells.This observation raises the question whether the enzyme is present in the cell at a time when the cell wall is not yet formed, such as in the germinating spore.We have therefore measured the level of this activity in the spore and at different times after spore activation (Fig. 1). The spore is practically devoid of single-stranded DNAse activity (less than 1% of the log-phase value, expressed as units per genome). The level of the DNase begins to increase only after DNA synthesis has started, when the vegetative cell begins to emerge from the spore. The DNase level, corrected for DNA content, rises exponentially thereafter to reach a value of approximately 20 TABLE 1.

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An Intracellular Endonuclease of Bacillus subtilis Specific for Single‐Stranded DNA

Cited by 10 publications

References 21 publications

Purification and properties of a manganese-stimulated deoxyribonuclease produced during sporulation of Bacillus subtilis

Purification and properties of a manganese-stimulated deoxyribonuclease produced during sporulation of Bacillus subtilis

Interannual hydrological variations and ecological phytoplankton patterns in Amazonian floodplain lakes

Bacillus subtilis deoxyribonuclease activity specific for single-stranded deoxyribonucleic acid: cellular site and variations during germination and sporulation

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