A rapid procedure for detecting and isolating plasmids of various sizes (2.6 to 350 Mdal) from bacteria such as Agrobacterium, Rhizobium, Escherichia, Salmonella, Erwinia, Pseudomonas, and Xanthomonas is described. The method uses the molecular characteristics of covalently closed circular DNA released from cells under alkaline conditions (pH 12.6) at elevated temperatures, which denature chromosomal DNA. Proteins and cell debris are removed by phenol-chloroform extraction, reducing or eliminating chromosomal DNA. The clarified extract is directly used for electrophoresis, allowing the selective isolation of plasmid DNA for use in various experiments. To detect plasmids, DNA is isolated by lysing cells with SDS and phenol-chloroform, followed by heat treatment to remove chromosomal DNA. The plasmid DNA is then resolved by electrophoresis in agarose gels. The procedure allows for the detection of plasmids within 3-4 hours from a small broth culture or a single colony. The method is efficient, reproducible, and applicable to many bacteria. The procedure involves lysing cells with SDS and phenol-chloroform, heating to denature chromosomal DNA, and extracting plasmid DNA. The plasmid DNA is then precipitated and resuspended for use in experiments. The method is suitable for restriction enzyme digestion, transformation, and nick translation. It is also applicable for the isolation of plasmid DNA from various bacteria, including those previously untested. The method is efficient, requiring less than 2 hours for plasmid isolation. It allows for the detection of plasmids ranging from 2.6 to 350 Mdal. The procedure is applicable to various bacteria, including Agrobacterium, Rhizobium, and Pseudomonas species. The method is also applicable for the isolation of plasmid DNA from yeast cells, facilitating rapid screening of genetically modified yeasts. The procedure is efficient, reproducible, and suitable for various applications, including restriction analysis, cloning, and transformation. The method is supported by references to previous studies and is applicable to a wide range of bacteria.A rapid procedure for detecting and isolating plasmids of various sizes (2.6 to 350 Mdal) from bacteria such as Agrobacterium, Rhizobium, Escherichia, Salmonella, Erwinia, Pseudomonas, and Xanthomonas is described. The method uses the molecular characteristics of covalently closed circular DNA released from cells under alkaline conditions (pH 12.6) at elevated temperatures, which denature chromosomal DNA. Proteins and cell debris are removed by phenol-chloroform extraction, reducing or eliminating chromosomal DNA. The clarified extract is directly used for electrophoresis, allowing the selective isolation of plasmid DNA for use in various experiments. To detect plasmids, DNA is isolated by lysing cells with SDS and phenol-chloroform, followed by heat treatment to remove chromosomal DNA. The plasmid DNA is then resolved by electrophoresis in agarose gels. The procedure allows for the detection of plasmids within 3-4 hours from a small broth culture or a single colony. The method is efficient, reproducible, and applicable to many bacteria. The procedure involves lysing cells with SDS and phenol-chloroform, heating to denature chromosomal DNA, and extracting plasmid DNA. The plasmid DNA is then precipitated and resuspended for use in experiments. The method is suitable for restriction enzyme digestion, transformation, and nick translation. It is also applicable for the isolation of plasmid DNA from various bacteria, including those previously untested. The method is efficient, requiring less than 2 hours for plasmid isolation. It allows for the detection of plasmids ranging from 2.6 to 350 Mdal. The procedure is applicable to various bacteria, including Agrobacterium, Rhizobium, and Pseudomonas species. The method is also applicable for the isolation of plasmid DNA from yeast cells, facilitating rapid screening of genetically modified yeasts. The procedure is efficient, reproducible, and suitable for various applications, including restriction analysis, cloning, and transformation. The method is supported by references to previous studies and is applicable to a wide range of bacteria.