Leszek Kauc - Academia.edu (original) (raw)

Papers by Leszek Kauc

Research paper thumbnail of Comparison of HP1c1 and S2 phages of Haemophilus influenzae

Acta microbiologica Polonica, 1986

Physical maps constructed by localization of the cleavage sites of several restriction endonuclea... more Physical maps constructed by localization of the cleavage sites of several restriction endonucleases have shown that the chromosome of Haemophilus influenzae bacteriophage S2 and HP1c1 can possess different types of molecular organization (Piekarowicz, Brzezinski, Smorawinska, Kauc, Skowronek, Lenarczyk & Gołembiewska, 1986). We have compared the physical maps of the HP1c1 and S2 phage DNAs of type B and the results led us to conclude that there are no differences between these two phages of the same type of molecular organization of the genomes, i.e. S2 and HP1c1 is the same phage. We also suggest that some of the fine differences between these two phages noted in some laboratories were induced only by different type of genome of the same phage.

Research paper thumbnail of Purification and Properties of a New Restriction Endonuclease from Haemophilus influenzae Rf

European Journal of Biochemistry, 1978

Huemophilus influenzue Rf 232, showing the phenomena of restriction and modification, contains an... more Huemophilus influenzue Rf 232, showing the phenomena of restriction and modification, contains an endonuclease that inactivates in vitvo the biological activity of DNAs lacking the strain-specific modification. This specific restriction endonuclease has been purified to near homogeneity by a procedure that includes DNA-agarose chromatography. This highly purified enzyme requires ATP and Mg2+ for activity and is stimulated by S-adenosylmethionine. The enzyme seems to cleave DNA at well-defined sites, since it produces a specific pattern of bands upon agarose gel electrophoresis. The enzyme has no ATPase activity. A methylase activity is observed in the course of the endonucleolytic reaction, which probably protects some of the DNA sites from cleavage.

Research paper thumbnail of Electroporation of Haemophilus influenzae is effective for transformation of plasmid but not chromosomal DNA

Nucleic Acids Research, 1991

Electroporation of plasmid and chromosomal DNAs were tested in Haemophilus influenzae because of ... more Electroporation of plasmid and chromosomal DNAs were tested in Haemophilus influenzae because of an interest in introducing DNA into mutants that are deficient in competence for transformation. The initial experiments were designed to investigate and optimize conditions for electroporation of H.influenzae. Plasmid DNA was introduced into the competence proficient strain Rd and its competence-deficient uptake mutants com-52, com-59, and com-88, and the recombination deficient mutant recl. Plasmid DNA could also be electroporated into the non-transforming strains Ra, Rc, Re and Rf. Plasmid DNA without sequences that are involved in tight binding (uptake) of DNA by competent cells of H.influenzae Rd was electroporated into both competent and non-competent cells.

Research paper thumbnail of An Haemophilus influenzae mutant which inhibits the growth of HP1c1 phage

MGG Molecular & General Genetics, 1975

A strain of Haemophilus influenzae, called hpm- inhibits the growth of phage HP1c1 but not S2. Th... more A strain of Haemophilus influenzae, called hpm- inhibits the growth of phage HP1c1 but not S2. This inhibition is overcome by HP1c1ph mutants. Phage HP1c1 adsorbs normally to hpm- cells but only a small fraction of infected cells produce phage with a normal burst size or become lysogenic. When hpm- strains lysogenic for HP1c1 are induced, 100 percent of the cells yield phage. There is no degradation of phage DNA after infection of hpm- cells and HP1c1 can normally grow when its DNA is introduced into hpm- by transfection. The most probable explanation is that in hpm- cells the penetration of phage DNA is blocked. The hpm- property behaves as as unstable mutation.

Research paper thumbnail of The size and a physical map of the chromosome of Haemophilus parainfluenzae

Gene, 1989

A variation of pulse-field electrophoresis, field-inversion gel electrophoresis, was used to dete... more A variation of pulse-field electrophoresis, field-inversion gel electrophoresis, was used to determine the size and physical map of the chromosome of Haemophilus influenzae. The DNA of H. influenzae had a low G+C content (39%) and no restriction sites for the enzymes NotI or Sfl. However, a number of restriction enzymes (SmaI, Apal, NaeI, and SacII) that recognized 6-base-pair sequences containing only G and C nucleotides were found to generate a reasonable number of DNA fragments that were separable in agarose gels by field-inversion gel electrophoresis. The sizes of the DNA fragments were calibrated with a lambda DNA ladder and lambda DNA restriction fragments. The sum of fragment sizes obtained with restriction digests yielded a value for the chromosome of 1,980 kilobase pairs. Hybridization of a labeled fragment with two or more fragments from a digest with a different restriction enzyme provided the information needed to construct a circular map of the H. influenzae chromosome.

Research paper thumbnail of Major spontaneous genomic rearrangements in Haemophilus influenzae S2 and HP1c1 bacteriophages

Gene, 1986

Physical maps constructed by the localization of the cleavage site of several restriction endonuc... more Physical maps constructed by the localization of the cleavage site of several restriction endonucleases have shown that the genomes of the Haemophilus bacteriophages S2 and HPlc 1 exist in variant forms which differ in the molecular organization of the genomes. At least three regions of different org~ization of the bacteriophage chromosomes have been identified.

Research paper thumbnail of The genome of Haemophilus influenzae Rd has a unique NotI site

Gene, 1990

Previous analysis of physical maps of Haemophilus influenzae, which is circular and 1.9 Mb in len... more Previous analysis of physical maps of Haemophilus influenzae, which is circular and 1.9 Mb in length [Lee and Smith, J. Bacteriol. 170 (1988) 4402-4405; Kauc et al., J. Bacteriol. 171 (1989) 2474-2479], did not detect any NotI (GCGGCCGC) restriction sites. A transposon, Tn916, was constructed to contain a NotI linker cloned into its NciI site and introduced into the H. influenzae chromosome. NotI digestion of chromosomes containing a Tn916-associated NotI site followed by separation of fragments by field-inversion gel electrophoresis revealed the presence of two fragments obtained by two NotI cuts, one in Tn916 and the other, a unique, 'natural' NotI site in the original chromosomal DNA. The examination of other Haemophilus strains demonstrated the presence of one or more NotI sites in all of those tested.

Research paper thumbnail of Host specificity of DNA in : Restriction and modification in strain R

Biochemical and Biophysical Research Communications, 1972

Research paper thumbnail of Major spontaneous genomic rearrangements in Haemophilus influenzae S2 and HP1c1 bacteriophages

Gene, 1986

Physical maps constructed by the localization of the cleavage site of several restriction endonuc... more Physical maps constructed by the localization of the cleavage site of several restriction endonucleases have shown that the genomes of the Haemophilus bacteriophages S2 and HPlc 1 exist in variant forms which differ in the molecular organization of the genomes. At least three regions of different org~ization of the bacteriophage chromosomes have been identified.

Research paper thumbnail of Host specificity of DNA in Haemophilus influenzae: similarity between host-specificity types of Haemophilus influenzae Re and Rf

Journal of general microbiology, 1974

Haemophilus inzuenzae Rf possesses two distinct host specificity systems FI and F2 each of which ... more Haemophilus inzuenzae Rf possesses two distinct host specificity systems FI and F2 each of which is able to restrict and modify Haemophilus phage HPICI, while strain ~b possesses only one system, B. Among restriction-deficient mutants isolated from strain ~f , the r-m+ as well as r-m-phenotypes for these two systems were obtained after either one or two mutational steps. The FI system was introduced into H. influenzae Rd by genetic transformation to show that the DI and FI systems are not allelic. Downloaded from www.microbiologyresearch.org by IP: 54.147.215.157 On: Fri, 16 Dec 2016 08:57:32

Research paper thumbnail of Comparison of HP1c1 and S2 phages of Haemophilus influenzae

Acta microbiologica Polonica

Physical maps constructed by localization of the cleavage sites of several restriction endonuclea... more Physical maps constructed by localization of the cleavage sites of several restriction endonucleases have shown that the chromosome of Haemophilus influenzae bacteriophage S2 and HP1c1 can possess different types of molecular organization (Piekarowicz, Brzezinski, Smorawinska, Kauc, Skowronek, Lenarczyk & Gołembiewska, 1986). We have compared the physical maps of the HP1c1 and S2 phage DNAs of type B and the results led us to conclude that there are no differences between these two phages of the same type of molecular organization of the genomes, i.e. S2 and HP1c1 is the same phage. We also suggest that some of the fine differences between these two phages noted in some laboratories were induced only by different type of genome of the same phage.

Research paper thumbnail of Purification and Properties of a New Restriction Endonuclease from Haemophilus influenzae Rf

European Journal of Biochemistry, 1978

Huemophilus influenzue Rf 232, showing the phenomena of restriction and modification, contains an... more Huemophilus influenzue Rf 232, showing the phenomena of restriction and modification, contains an endonuclease that inactivates in vitvo the biological activity of DNAs lacking the strain-specific modification. This specific restriction endonuclease has been purified to near homogeneity by a procedure that includes DNA-agarose chromatography. This highly purified enzyme requires ATP and Mg2+ for activity and is stimulated by S-adenosylmethionine. The enzyme seems to cleave DNA at well-defined sites, since it produces a specific pattern of bands upon agarose gel electrophoresis. The enzyme has no ATPase activity. A methylase activity is observed in the course of the endonucleolytic reaction, which probably protects some of the DNA sites from cleavage.

Research paper thumbnail of An Haemophilus influenzae mutant which inhibits the growth of HP1c1 phage

MGG Molecular & General Genetics, 1975

A strain of Haemophilus influenzae, called hpm- inhibits the growth of phage HP1c1 but not S2. Th... more A strain of Haemophilus influenzae, called hpm- inhibits the growth of phage HP1c1 but not S2. This inhibition is overcome by HP1c1ph mutants. Phage HP1c1 adsorbs normally to hpm- cells but only a small fraction of infected cells produce phage with a normal burst size or become lysogenic. When hpm- strains lysogenic for HP1c1 are induced, 100 percent of the cells yield phage. There is no degradation of phage DNA after infection of hpm- cells and HP1c1 can normally grow when its DNA is introduced into hpm- by transfection. The most probable explanation is that in hpm- cells the penetration of phage DNA is blocked. The hpm- property behaves as as unstable mutation.

Research paper thumbnail of The size and a physical map of the chromosome of Haemophilus parainfluenzae

Gene, 1989

A variation of pulse-field electrophoresis, field-inversion gel electrophoresis, was used to dete... more A variation of pulse-field electrophoresis, field-inversion gel electrophoresis, was used to determine the size and physical map of the chromosome of Haemophilus influenzae. The DNA of H. influenzae had a low G+C content (39%) and no restriction sites for the enzymes NotI or Sfl. However, a number of restriction enzymes (SmaI, Apal, NaeI, and SacII) that recognized 6-base-pair sequences containing only G and C nucleotides were found to generate a reasonable number of DNA fragments that were separable in agarose gels by field-inversion gel electrophoresis. The sizes of the DNA fragments were calibrated with a lambda DNA ladder and lambda DNA restriction fragments. The sum of fragment sizes obtained with restriction digests yielded a value for the chromosome of 1,980 kilobase pairs. Hybridization of a labeled fragment with two or more fragments from a digest with a different restriction enzyme provided the information needed to construct a circular map of the H. influenzae chromosome.

Research paper thumbnail of Major spontaneous genomic rearrangements in Haemophilus influenzae S2 and HP1c1 bacteriophages

Gene, 1986

Physical maps constructed by the localization of the cleavage site of several restriction endonuc... more Physical maps constructed by the localization of the cleavage site of several restriction endonucleases have shown that the genomes of the Haemophilus bacteriophages S2 and HPlc 1 exist in variant forms which differ in the molecular organization of the genomes. At least three regions of different org~ization of the bacteriophage chromosomes have been identified.

Research paper thumbnail of The genome of Haemophilus influenzae Rd has a unique NotI site

Gene, 1990

Previous analysis of physical maps of Haemophilus influenzae, which is circular and 1.9 Mb in len... more Previous analysis of physical maps of Haemophilus influenzae, which is circular and 1.9 Mb in length [Lee and Smith, J. Bacteriol. 170 (1988) 4402-4405; Kauc et al., J. Bacteriol. 171 (1989) 2474-2479], did not detect any NotI (GCGGCCGC) restriction sites. A transposon, Tn916, was constructed to contain a NotI linker cloned into its NciI site and introduced into the H. influenzae chromosome. NotI digestion of chromosomes containing a Tn916-associated NotI site followed by separation of fragments by field-inversion gel electrophoresis revealed the presence of two fragments obtained by two NotI cuts, one in Tn916 and the other, a unique, 'natural' NotI site in the original chromosomal DNA. The examination of other Haemophilus strains demonstrated the presence of one or more NotI sites in all of those tested.

Research paper thumbnail of Electroporation of Haemophilus influenzae is effective for transformation of plasmid but not chromosomal DNA

Nucleic Acids Research, 1991

Electroporation of plasmid and chromosomal DNAs were tested in Haemophilus influenzae because of ... more Electroporation of plasmid and chromosomal DNAs were tested in Haemophilus influenzae because of an interest in introducing DNA into mutants that are deficient in competence for transformation. The initial experiments were designed to investigate and optimize conditions for electroporation of H.influenzae. Plasmid DNA was introduced into the competence proficient strain Rd and its competence-deficient uptake mutants com-52, com-59, and com-88, and the recombination deficient mutant recl. Plasmid DNA could also be electroporated into the non-transforming strains Ra, Rc, Re and Rf. Plasmid DNA without sequences that are involved in tight binding (uptake) of DNA by competent cells of H.influenzae Rd was electroporated into both competent and non-competent cells.

Research paper thumbnail of Comparison of HP1c1 and S2 phages of Haemophilus influenzae

Acta microbiologica Polonica, 1986

Physical maps constructed by localization of the cleavage sites of several restriction endonuclea... more Physical maps constructed by localization of the cleavage sites of several restriction endonucleases have shown that the chromosome of Haemophilus influenzae bacteriophage S2 and HP1c1 can possess different types of molecular organization (Piekarowicz, Brzezinski, Smorawinska, Kauc, Skowronek, Lenarczyk & Gołembiewska, 1986). We have compared the physical maps of the HP1c1 and S2 phage DNAs of type B and the results led us to conclude that there are no differences between these two phages of the same type of molecular organization of the genomes, i.e. S2 and HP1c1 is the same phage. We also suggest that some of the fine differences between these two phages noted in some laboratories were induced only by different type of genome of the same phage.

Research paper thumbnail of Purification and Properties of a New Restriction Endonuclease from Haemophilus influenzae Rf

European Journal of Biochemistry, 1978

Huemophilus influenzue Rf 232, showing the phenomena of restriction and modification, contains an... more Huemophilus influenzue Rf 232, showing the phenomena of restriction and modification, contains an endonuclease that inactivates in vitvo the biological activity of DNAs lacking the strain-specific modification. This specific restriction endonuclease has been purified to near homogeneity by a procedure that includes DNA-agarose chromatography. This highly purified enzyme requires ATP and Mg2+ for activity and is stimulated by S-adenosylmethionine. The enzyme seems to cleave DNA at well-defined sites, since it produces a specific pattern of bands upon agarose gel electrophoresis. The enzyme has no ATPase activity. A methylase activity is observed in the course of the endonucleolytic reaction, which probably protects some of the DNA sites from cleavage.

Research paper thumbnail of Electroporation of Haemophilus influenzae is effective for transformation of plasmid but not chromosomal DNA

Nucleic Acids Research, 1991

Electroporation of plasmid and chromosomal DNAs were tested in Haemophilus influenzae because of ... more Electroporation of plasmid and chromosomal DNAs were tested in Haemophilus influenzae because of an interest in introducing DNA into mutants that are deficient in competence for transformation. The initial experiments were designed to investigate and optimize conditions for electroporation of H.influenzae. Plasmid DNA was introduced into the competence proficient strain Rd and its competence-deficient uptake mutants com-52, com-59, and com-88, and the recombination deficient mutant recl. Plasmid DNA could also be electroporated into the non-transforming strains Ra, Rc, Re and Rf. Plasmid DNA without sequences that are involved in tight binding (uptake) of DNA by competent cells of H.influenzae Rd was electroporated into both competent and non-competent cells.

Research paper thumbnail of An Haemophilus influenzae mutant which inhibits the growth of HP1c1 phage

MGG Molecular & General Genetics, 1975

A strain of Haemophilus influenzae, called hpm- inhibits the growth of phage HP1c1 but not S2. Th... more A strain of Haemophilus influenzae, called hpm- inhibits the growth of phage HP1c1 but not S2. This inhibition is overcome by HP1c1ph mutants. Phage HP1c1 adsorbs normally to hpm- cells but only a small fraction of infected cells produce phage with a normal burst size or become lysogenic. When hpm- strains lysogenic for HP1c1 are induced, 100 percent of the cells yield phage. There is no degradation of phage DNA after infection of hpm- cells and HP1c1 can normally grow when its DNA is introduced into hpm- by transfection. The most probable explanation is that in hpm- cells the penetration of phage DNA is blocked. The hpm- property behaves as as unstable mutation.

Research paper thumbnail of The size and a physical map of the chromosome of Haemophilus parainfluenzae

Gene, 1989

A variation of pulse-field electrophoresis, field-inversion gel electrophoresis, was used to dete... more A variation of pulse-field electrophoresis, field-inversion gel electrophoresis, was used to determine the size and physical map of the chromosome of Haemophilus influenzae. The DNA of H. influenzae had a low G+C content (39%) and no restriction sites for the enzymes NotI or Sfl. However, a number of restriction enzymes (SmaI, Apal, NaeI, and SacII) that recognized 6-base-pair sequences containing only G and C nucleotides were found to generate a reasonable number of DNA fragments that were separable in agarose gels by field-inversion gel electrophoresis. The sizes of the DNA fragments were calibrated with a lambda DNA ladder and lambda DNA restriction fragments. The sum of fragment sizes obtained with restriction digests yielded a value for the chromosome of 1,980 kilobase pairs. Hybridization of a labeled fragment with two or more fragments from a digest with a different restriction enzyme provided the information needed to construct a circular map of the H. influenzae chromosome.

Research paper thumbnail of Major spontaneous genomic rearrangements in Haemophilus influenzae S2 and HP1c1 bacteriophages

Gene, 1986

Physical maps constructed by the localization of the cleavage site of several restriction endonuc... more Physical maps constructed by the localization of the cleavage site of several restriction endonucleases have shown that the genomes of the Haemophilus bacteriophages S2 and HPlc 1 exist in variant forms which differ in the molecular organization of the genomes. At least three regions of different org~ization of the bacteriophage chromosomes have been identified.

Research paper thumbnail of The genome of Haemophilus influenzae Rd has a unique NotI site

Gene, 1990

Previous analysis of physical maps of Haemophilus influenzae, which is circular and 1.9 Mb in len... more Previous analysis of physical maps of Haemophilus influenzae, which is circular and 1.9 Mb in length [Lee and Smith, J. Bacteriol. 170 (1988) 4402-4405; Kauc et al., J. Bacteriol. 171 (1989) 2474-2479], did not detect any NotI (GCGGCCGC) restriction sites. A transposon, Tn916, was constructed to contain a NotI linker cloned into its NciI site and introduced into the H. influenzae chromosome. NotI digestion of chromosomes containing a Tn916-associated NotI site followed by separation of fragments by field-inversion gel electrophoresis revealed the presence of two fragments obtained by two NotI cuts, one in Tn916 and the other, a unique, 'natural' NotI site in the original chromosomal DNA. The examination of other Haemophilus strains demonstrated the presence of one or more NotI sites in all of those tested.

Research paper thumbnail of Host specificity of DNA in : Restriction and modification in strain R

Biochemical and Biophysical Research Communications, 1972

Research paper thumbnail of Major spontaneous genomic rearrangements in Haemophilus influenzae S2 and HP1c1 bacteriophages

Gene, 1986

Physical maps constructed by the localization of the cleavage site of several restriction endonuc... more Physical maps constructed by the localization of the cleavage site of several restriction endonucleases have shown that the genomes of the Haemophilus bacteriophages S2 and HPlc 1 exist in variant forms which differ in the molecular organization of the genomes. At least three regions of different org~ization of the bacteriophage chromosomes have been identified.

Research paper thumbnail of Host specificity of DNA in Haemophilus influenzae: similarity between host-specificity types of Haemophilus influenzae Re and Rf

Journal of general microbiology, 1974

Haemophilus inzuenzae Rf possesses two distinct host specificity systems FI and F2 each of which ... more Haemophilus inzuenzae Rf possesses two distinct host specificity systems FI and F2 each of which is able to restrict and modify Haemophilus phage HPICI, while strain ~b possesses only one system, B. Among restriction-deficient mutants isolated from strain ~f , the r-m+ as well as r-m-phenotypes for these two systems were obtained after either one or two mutational steps. The FI system was introduced into H. influenzae Rd by genetic transformation to show that the DI and FI systems are not allelic. Downloaded from www.microbiologyresearch.org by IP: 54.147.215.157 On: Fri, 16 Dec 2016 08:57:32

Research paper thumbnail of Comparison of HP1c1 and S2 phages of Haemophilus influenzae

Acta microbiologica Polonica

Physical maps constructed by localization of the cleavage sites of several restriction endonuclea... more Physical maps constructed by localization of the cleavage sites of several restriction endonucleases have shown that the chromosome of Haemophilus influenzae bacteriophage S2 and HP1c1 can possess different types of molecular organization (Piekarowicz, Brzezinski, Smorawinska, Kauc, Skowronek, Lenarczyk & Gołembiewska, 1986). We have compared the physical maps of the HP1c1 and S2 phage DNAs of type B and the results led us to conclude that there are no differences between these two phages of the same type of molecular organization of the genomes, i.e. S2 and HP1c1 is the same phage. We also suggest that some of the fine differences between these two phages noted in some laboratories were induced only by different type of genome of the same phage.

Research paper thumbnail of Purification and Properties of a New Restriction Endonuclease from Haemophilus influenzae Rf

European Journal of Biochemistry, 1978

Huemophilus influenzue Rf 232, showing the phenomena of restriction and modification, contains an... more Huemophilus influenzue Rf 232, showing the phenomena of restriction and modification, contains an endonuclease that inactivates in vitvo the biological activity of DNAs lacking the strain-specific modification. This specific restriction endonuclease has been purified to near homogeneity by a procedure that includes DNA-agarose chromatography. This highly purified enzyme requires ATP and Mg2+ for activity and is stimulated by S-adenosylmethionine. The enzyme seems to cleave DNA at well-defined sites, since it produces a specific pattern of bands upon agarose gel electrophoresis. The enzyme has no ATPase activity. A methylase activity is observed in the course of the endonucleolytic reaction, which probably protects some of the DNA sites from cleavage.

Research paper thumbnail of An Haemophilus influenzae mutant which inhibits the growth of HP1c1 phage

MGG Molecular & General Genetics, 1975

A strain of Haemophilus influenzae, called hpm- inhibits the growth of phage HP1c1 but not S2. Th... more A strain of Haemophilus influenzae, called hpm- inhibits the growth of phage HP1c1 but not S2. This inhibition is overcome by HP1c1ph mutants. Phage HP1c1 adsorbs normally to hpm- cells but only a small fraction of infected cells produce phage with a normal burst size or become lysogenic. When hpm- strains lysogenic for HP1c1 are induced, 100 percent of the cells yield phage. There is no degradation of phage DNA after infection of hpm- cells and HP1c1 can normally grow when its DNA is introduced into hpm- by transfection. The most probable explanation is that in hpm- cells the penetration of phage DNA is blocked. The hpm- property behaves as as unstable mutation.

Research paper thumbnail of The size and a physical map of the chromosome of Haemophilus parainfluenzae

Gene, 1989

A variation of pulse-field electrophoresis, field-inversion gel electrophoresis, was used to dete... more A variation of pulse-field electrophoresis, field-inversion gel electrophoresis, was used to determine the size and physical map of the chromosome of Haemophilus influenzae. The DNA of H. influenzae had a low G+C content (39%) and no restriction sites for the enzymes NotI or Sfl. However, a number of restriction enzymes (SmaI, Apal, NaeI, and SacII) that recognized 6-base-pair sequences containing only G and C nucleotides were found to generate a reasonable number of DNA fragments that were separable in agarose gels by field-inversion gel electrophoresis. The sizes of the DNA fragments were calibrated with a lambda DNA ladder and lambda DNA restriction fragments. The sum of fragment sizes obtained with restriction digests yielded a value for the chromosome of 1,980 kilobase pairs. Hybridization of a labeled fragment with two or more fragments from a digest with a different restriction enzyme provided the information needed to construct a circular map of the H. influenzae chromosome.

Research paper thumbnail of Major spontaneous genomic rearrangements in Haemophilus influenzae S2 and HP1c1 bacteriophages

Gene, 1986

Physical maps constructed by the localization of the cleavage site of several restriction endonuc... more Physical maps constructed by the localization of the cleavage site of several restriction endonucleases have shown that the genomes of the Haemophilus bacteriophages S2 and HPlc 1 exist in variant forms which differ in the molecular organization of the genomes. At least three regions of different org~ization of the bacteriophage chromosomes have been identified.

Research paper thumbnail of The genome of Haemophilus influenzae Rd has a unique NotI site

Gene, 1990

Previous analysis of physical maps of Haemophilus influenzae, which is circular and 1.9 Mb in len... more Previous analysis of physical maps of Haemophilus influenzae, which is circular and 1.9 Mb in length [Lee and Smith, J. Bacteriol. 170 (1988) 4402-4405; Kauc et al., J. Bacteriol. 171 (1989) 2474-2479], did not detect any NotI (GCGGCCGC) restriction sites. A transposon, Tn916, was constructed to contain a NotI linker cloned into its NciI site and introduced into the H. influenzae chromosome. NotI digestion of chromosomes containing a Tn916-associated NotI site followed by separation of fragments by field-inversion gel electrophoresis revealed the presence of two fragments obtained by two NotI cuts, one in Tn916 and the other, a unique, 'natural' NotI site in the original chromosomal DNA. The examination of other Haemophilus strains demonstrated the presence of one or more NotI sites in all of those tested.

Research paper thumbnail of Electroporation of Haemophilus influenzae is effective for transformation of plasmid but not chromosomal DNA

Nucleic Acids Research, 1991

Electroporation of plasmid and chromosomal DNAs were tested in Haemophilus influenzae because of ... more Electroporation of plasmid and chromosomal DNAs were tested in Haemophilus influenzae because of an interest in introducing DNA into mutants that are deficient in competence for transformation. The initial experiments were designed to investigate and optimize conditions for electroporation of H.influenzae. Plasmid DNA was introduced into the competence proficient strain Rd and its competence-deficient uptake mutants com-52, com-59, and com-88, and the recombination deficient mutant recl. Plasmid DNA could also be electroporated into the non-transforming strains Ra, Rc, Re and Rf. Plasmid DNA without sequences that are involved in tight binding (uptake) of DNA by competent cells of H.influenzae Rd was electroporated into both competent and non-competent cells.