Degradation of Adsorbed Transforming DNA by Haemophilus influenzae

Streptococcus sanguis (Wicky) cells, strain WE4, developed little or no competence and failed to autolyze in permissive conditions when treated with competence factor (CF) below PH 7.0. This lack of activity was directly correlated with the inability of the cells to bind or take up CF at pH values of 5.5, 6.0, and 6.5. On the other hand, competent cells bound deoxyribonucleic acid molecules maximally below pH 7.0 and transformed maximally at pH 6.5. Deoxyribonucleic acid was optimally bound to cells in a deoxyribonuclease-resistant form at pH values between 7.0 and 8.5. Concomitant with this binding, undefined acid-soluble DNA fragments appeared in the culture menstrua. CF binding and uptake by cells was not only influenced by low pH but also by low temperature. At 0 C, WE4 cells bound only 4% of the input CF and took up less than 1% into a trypsin-insensitive state compared to cells treated at 37 C. Cells treated with CF at 0 C did not autolyze when transferred to permissive conditions. The results presented in this report extend earlier findings that showed that competence development and autolysis are related to the uptake of CF.

“…2) has not been previously demonstrated. In this regard, competent WE4 cells resemble other competent bacteria (2,8,18,19). Noncompetent cells do not produce acid-soluble fragments.…”

Section: Discussionmentioning

confidence: 88%

Effect of pH on competence development and deoxyribonucleic acid uptake in Streptococcus sanguis (Wicky)

Ranhand¹

1976

“…DNaseresistant DNA binding to both organisms demonstrated a brief lag (from 1 to 3 s), was saturated after 5 to 10 min of exposure to excess DNA (11,39), and occurred outside the cytoplasmic membrane (10,17). In both transformation systems, DNA uptake was not accompanied by the release of an equivalent amount of acid-soluble deoxyribonucleotides from the cell surface (40). Therefore, a nuclease such as that active in gram-positive transformation systems (19,27), which generates single-stranded DNA during uptake, does not have an equivalent role in A. vinelandii transformation.…”

Section: Discussionmentioning

confidence: 99%

Heat sensitivity of Azotobacter vinelandii genetic transformation

Doran¹,

Page²

1983

MATERIALS AND METHODSBacterial strains and growth conditions. The transformation recipient A. vinelandii OP strain UW1 (Nif capsule-) and the parental strain UW (Nif+ capsule-) were provided by W. Brill (University of Wisconsin, Madison). A. vinelandii ATCC 12837 strains 113 (Nif+ rifampin resistant) and 114 (Nif+ streptomycin resistant) and the diazotrophs Azotobacter chroococcum ATCC 7486, Azotobacterpaspali ATCC 23368, Azotobacter beierinckii ATCC 19360, Azomonas macrocytogenes ATCC 12335, Azomonas insignis, Beijerinckia indica ATCC 12523, Rhizobium meliloti 17A, Rhizobi-159 on August 2, 2020 by guest

“…The three main features that characterize in general terms the fate of H. influenzae transforming DNA after adsorption are (i) acid solubilization of about 25% (12,26), (ii) biological inactivation of about 75% (12,22,30), and (iii) integration (22) through single-strand insertion (19). It may be an attractive idea to combine these three processes in one model describing the whole transformation process.…”

Section: Discussionmentioning

confidence: 99%

“…MATERIALS Media and DNA isolation and transformation techniques. Media used have been described (21,26). Radioactive DNA was extracted from cells grown in Herriott chemically defined medium (11) without phosphate but with 3% of a 3.7% brain heart infusion (Difco) solution added.…”

mentioning

confidence: 99%

Acid-Soluble Breakdown of Homologous Deoxyribonucleic Acid Adsorbed by Haemophilus influenzae : Its Biological Significance

Stuy

1974

Competent bacteria of Haemophilus influenzae strain Rd were exposed to various kinds of radioactive deoxyribonucleic acid (DNA) for short periods of time and at relatively low temperature. The fate of phage HP1 DNA was studied most extensively. Adsorbed DNA was partially acid solubilized by lysogens and by nonlysogens with very similar kinetics. The biological activity of the DNA decreased extensively in both lysogenic and nonlysogenic recipients. 2,4-Dinitrophenol had no effect on the acid solubilization but largely abolished the biological inactivation. Inactivation kinetics for three different markers and for the triple combination were roughly the same. The presence of 2,4-dinitrophenol in the medium, or the HP1 prophage in the chromosome, did not alter this observation. This suggests that acid solubilization involves the destruction of whole DNA molecules. In view of the absence of DNA homology between phage and host, it is concluded that acid-soluble breakdown of adsorbed transforming DNA is not an integral part of the donor DNA integration process. Behavior of mutant bacteria indicates that neither exonuclease III nor exonuclease V is involved.