Experience

Publications

• Halocins: Protein Antibiotics from Hypersaline Environments. In, Microbiology and Biogeochemistry of Hypersaline Environments, A. Oren, Ed.

  CRC Press

  To see text on Google Books: https://books.google.com/books?id=rBk1hHU1zx8C&lpg=PA297&ots=SLmV-ojmFp&dq=Halocins%3A%20Protein%20Antibiotics%20from%20Hypersaline%20Environments&pg=PA296#v=onepage&q&f=true

• Halocins: Protein Antibiotics from Hypersaline Environments. In, Microbiology and Biogeochemistry of Hypersaline Environments, A. Oren, Ed.

  CRC Press

  To see text on Google Books: https://books.google.com/books?id=rBk1hHU1zx8C&lpg=PA297&ots=SLmV-ojmFp&dq=Halocins%3A%20Protein%20Antibiotics%20from%20Hypersaline%20Environments&pg=PA296#v=onepage&q&f=true

• Genome Sequence of a Sulfate-Reducing Thermophilic Bacterium, Thermodesulfobacterium commune DSM 2178T (Phylum Thermodesulfobacteria)

  Genome Announcements

  Here, we present the complete 2,003,803-bp genome of a sulfate-reducing thermophilic bacterium, Thermodesulfovibrio yellowstonii strain DSM 11347T.

• Halocins: Protein Antibiotics from Hypersaline Environments. In, Microbiology and Biogeochemistry of Hypersaline Environments, A. Oren, Ed.

  CRC Press

  To see text on Google Books: https://books.google.com/books?id=rBk1hHU1zx8C&lpg=PA297&ots=SLmV-ojmFp&dq=Halocins%3A%20Protein%20Antibiotics%20from%20Hypersaline%20Environments&pg=PA296#v=onepage&q&f=true

• Genome Sequence of a Sulfate-Reducing Thermophilic Bacterium, Thermodesulfobacterium commune DSM 2178T (Phylum Thermodesulfobacteria)

  Genome Announcements

  Here, we present the complete 2,003,803-bp genome of a sulfate-reducing thermophilic bacterium, Thermodesulfovibrio yellowstonii strain DSM 11347T.

• Halocins and Sulfolobicins: The Emerging Story of Archaeal Protein and Peptide Antibiotics

  Journal of Industrial Microbiology and Biotechnology

  Production of antibiotic peptides and proteins is a near-universal feature of living organisms regardless of phylogenetic classification. Bacteriocins (proteinaceous antimicrobials from the domain Bacteria) have been studied for over 75 years, and the eucaryocins (proteinaceous antimicrobials from the domain Eucarya) since the early 1960s. However, one domain of organisms, the Archaea, containing hyperthermophiles, extreme halophiles and the methanogens, is just beginning to be scrutinized for the production of peptide antibiotics. Production of archaeal proteinaceous antimicrobials (archaeocins) from extreme halophiles (halocins) is a nearly universal feature of the rod-shaped haloarchaea. Halocin activity is first detectable in culture supernatants at the beginning of the transition into stationary phase, concomitant with an induction of transcription of the structural gene. Halocins are diverse in size, consisting of proteins as large as 35 kDa and peptide "microhalocins" as small as 3.6 kDa. The 36 amino acids of microhalocin HalS8 are located in the interior of a 311-residue pro-protein from which they are liberated by an unknown mechanism. Microhalocins are hydrophobic and robust, withstanding heat, desalting and exposure to organic solvents. Unlike the peptide bacteriocins and the eucaryocins, microhalocins possess a large number of neutral residues and are not cationic, leaving their mechanism(s) of action mostly a mystery. While microhalocins affect a variety of haloarchaeal genera (kingdom Euryarchaeota), they also exhibit cross-kingdom toxicity, inhibiting or killing Sulfolobus species (kingdom Crenarchaeota). Finally, archaeocins also are produced by the hyperthermophile "Sulfolobus islandicus". These 20-kDa protein antibiotics are not excreted into the environment, but are associated with small particles apparently derived from the cell's S-layer.

• Halocins: Protein Antibiotics from Hypersaline Environments. In, Microbiology and Biogeochemistry of Hypersaline Environments, A. Oren, Ed.

  CRC Press

  To see text on Google Books: https://books.google.com/books?id=rBk1hHU1zx8C&lpg=PA297&ots=SLmV-ojmFp&dq=Halocins%3A%20Protein%20Antibiotics%20from%20Hypersaline%20Environments&pg=PA296#v=onepage&q&f=true

• Genome Sequence of a Sulfate-Reducing Thermophilic Bacterium, Thermodesulfobacterium commune DSM 2178T (Phylum Thermodesulfobacteria)

  Genome Announcements

  Here, we present the complete 2,003,803-bp genome of a sulfate-reducing thermophilic bacterium, Thermodesulfovibrio yellowstonii strain DSM 11347T.

• Halocins and Sulfolobicins: The Emerging Story of Archaeal Protein and Peptide Antibiotics

  Journal of Industrial Microbiology and Biotechnology

  Production of antibiotic peptides and proteins is a near-universal feature of living organisms regardless of phylogenetic classification. Bacteriocins (proteinaceous antimicrobials from the domain Bacteria) have been studied for over 75 years, and the eucaryocins (proteinaceous antimicrobials from the domain Eucarya) since the early 1960s. However, one domain of organisms, the Archaea, containing hyperthermophiles, extreme halophiles and the methanogens, is just beginning to be scrutinized for the production of peptide antibiotics. Production of archaeal proteinaceous antimicrobials (archaeocins) from extreme halophiles (halocins) is a nearly universal feature of the rod-shaped haloarchaea. Halocin activity is first detectable in culture supernatants at the beginning of the transition into stationary phase, concomitant with an induction of transcription of the structural gene. Halocins are diverse in size, consisting of proteins as large as 35 kDa and peptide "microhalocins" as small as 3.6 kDa. The 36 amino acids of microhalocin HalS8 are located in the interior of a 311-residue pro-protein from which they are liberated by an unknown mechanism. Microhalocins are hydrophobic and robust, withstanding heat, desalting and exposure to organic solvents. Unlike the peptide bacteriocins and the eucaryocins, microhalocins possess a large number of neutral residues and are not cationic, leaving their mechanism(s) of action mostly a mystery. While microhalocins affect a variety of haloarchaeal genera (kingdom Euryarchaeota), they also exhibit cross-kingdom toxicity, inhibiting or killing Sulfolobus species (kingdom Crenarchaeota). Finally, archaeocins also are produced by the hyperthermophile "Sulfolobus islandicus". These 20-kDa protein antibiotics are not excreted into the environment, but are associated with small particles apparently derived from the cell's S-layer.

• Purification and Characterization of Microhalocin R1 from Halobacterium salinarum GN101

  Ph.D. Dissertation, Northern Arizona University

• Halocins: Protein Antibiotics from Hypersaline Environments. In, Microbiology and Biogeochemistry of Hypersaline Environments, A. Oren, Ed.

  CRC Press

  To see text on Google Books: https://books.google.com/books?id=rBk1hHU1zx8C&lpg=PA297&ots=SLmV-ojmFp&dq=Halocins%3A%20Protein%20Antibiotics%20from%20Hypersaline%20Environments&pg=PA296#v=onepage&q&f=true

• Genome Sequence of a Sulfate-Reducing Thermophilic Bacterium, Thermodesulfobacterium commune DSM 2178T (Phylum Thermodesulfobacteria)

  Genome Announcements

  Here, we present the complete 2,003,803-bp genome of a sulfate-reducing thermophilic bacterium, Thermodesulfovibrio yellowstonii strain DSM 11347T.

• Halocins and Sulfolobicins: The Emerging Story of Archaeal Protein and Peptide Antibiotics

  Journal of Industrial Microbiology and Biotechnology

  Production of antibiotic peptides and proteins is a near-universal feature of living organisms regardless of phylogenetic classification. Bacteriocins (proteinaceous antimicrobials from the domain Bacteria) have been studied for over 75 years, and the eucaryocins (proteinaceous antimicrobials from the domain Eucarya) since the early 1960s. However, one domain of organisms, the Archaea, containing hyperthermophiles, extreme halophiles and the methanogens, is just beginning to be scrutinized for the production of peptide antibiotics. Production of archaeal proteinaceous antimicrobials (archaeocins) from extreme halophiles (halocins) is a nearly universal feature of the rod-shaped haloarchaea. Halocin activity is first detectable in culture supernatants at the beginning of the transition into stationary phase, concomitant with an induction of transcription of the structural gene. Halocins are diverse in size, consisting of proteins as large as 35 kDa and peptide "microhalocins" as small as 3.6 kDa. The 36 amino acids of microhalocin HalS8 are located in the interior of a 311-residue pro-protein from which they are liberated by an unknown mechanism. Microhalocins are hydrophobic and robust, withstanding heat, desalting and exposure to organic solvents. Unlike the peptide bacteriocins and the eucaryocins, microhalocins possess a large number of neutral residues and are not cationic, leaving their mechanism(s) of action mostly a mystery. While microhalocins affect a variety of haloarchaeal genera (kingdom Euryarchaeota), they also exhibit cross-kingdom toxicity, inhibiting or killing Sulfolobus species (kingdom Crenarchaeota). Finally, archaeocins also are produced by the hyperthermophile "Sulfolobus islandicus". These 20-kDa protein antibiotics are not excreted into the environment, but are associated with small particles apparently derived from the cell's S-layer.

• Purification and Characterization of Microhalocin R1 from Halobacterium salinarum GN101

  Ph.D. Dissertation, Northern Arizona University

• Isolation, sequence and expression of the gene encoding halocin H4, a bacteriocin from the halophilic archaeon, Haloferax mediterranei R4

  Journal of Bacteriology

  The first gene to encode a haloarchaeal bacteriocin (halocin H4) has been cloned and sequenced from Haloferax mediterranei R4. Both the signal sequence in the halocin H4 preprotein and the monocistronic halH4 gene have some unusual features. The physiology of halH4 expression reveals that although halH4 transcripts are present at low basal levels during exponential growth, halocin H4 activity first appears as the culture enters stationary phase. As halocin activity levels increase, so do transcript levels, but then activity levels decrease precipitously while transcript levels remain elevated.

• Halocins: Protein Antibiotics from Hypersaline Environments. In, Microbiology and Biogeochemistry of Hypersaline Environments, A. Oren, Ed.

  CRC Press

  To see text on Google Books: https://books.google.com/books?id=rBk1hHU1zx8C&lpg=PA297&ots=SLmV-ojmFp&dq=Halocins%3A%20Protein%20Antibiotics%20from%20Hypersaline%20Environments&pg=PA296#v=onepage&q&f=true

• Genome Sequence of a Sulfate-Reducing Thermophilic Bacterium, Thermodesulfobacterium commune DSM 2178T (Phylum Thermodesulfobacteria)

  Genome Announcements

  Here, we present the complete 2,003,803-bp genome of a sulfate-reducing thermophilic bacterium, Thermodesulfovibrio yellowstonii strain DSM 11347T.

• Halocins and Sulfolobicins: The Emerging Story of Archaeal Protein and Peptide Antibiotics

  Journal of Industrial Microbiology and Biotechnology

  Production of antibiotic peptides and proteins is a near-universal feature of living organisms regardless of phylogenetic classification. Bacteriocins (proteinaceous antimicrobials from the domain Bacteria) have been studied for over 75 years, and the eucaryocins (proteinaceous antimicrobials from the domain Eucarya) since the early 1960s. However, one domain of organisms, the Archaea, containing hyperthermophiles, extreme halophiles and the methanogens, is just beginning to be scrutinized for the production of peptide antibiotics. Production of archaeal proteinaceous antimicrobials (archaeocins) from extreme halophiles (halocins) is a nearly universal feature of the rod-shaped haloarchaea. Halocin activity is first detectable in culture supernatants at the beginning of the transition into stationary phase, concomitant with an induction of transcription of the structural gene. Halocins are diverse in size, consisting of proteins as large as 35 kDa and peptide "microhalocins" as small as 3.6 kDa. The 36 amino acids of microhalocin HalS8 are located in the interior of a 311-residue pro-protein from which they are liberated by an unknown mechanism. Microhalocins are hydrophobic and robust, withstanding heat, desalting and exposure to organic solvents. Unlike the peptide bacteriocins and the eucaryocins, microhalocins possess a large number of neutral residues and are not cationic, leaving their mechanism(s) of action mostly a mystery. While microhalocins affect a variety of haloarchaeal genera (kingdom Euryarchaeota), they also exhibit cross-kingdom toxicity, inhibiting or killing Sulfolobus species (kingdom Crenarchaeota). Finally, archaeocins also are produced by the hyperthermophile "Sulfolobus islandicus". These 20-kDa protein antibiotics are not excreted into the environment, but are associated with small particles apparently derived from the cell's S-layer.

• Purification and Characterization of Microhalocin R1 from Halobacterium salinarum GN101

  Ph.D. Dissertation, Northern Arizona University

• Isolation, sequence and expression of the gene encoding halocin H4, a bacteriocin from the halophilic archaeon, Haloferax mediterranei R4

  Journal of Bacteriology

  The first gene to encode a haloarchaeal bacteriocin (halocin H4) has been cloned and sequenced from Haloferax mediterranei R4. Both the signal sequence in the halocin H4 preprotein and the monocistronic halH4 gene have some unusual features. The physiology of halH4 expression reveals that although halH4 transcripts are present at low basal levels during exponential growth, halocin H4 activity first appears as the culture enters stationary phase. As halocin activity levels increase, so do transcript levels, but then activity levels decrease precipitously while transcript levels remain elevated.

• Genome Sequence of the Sulfate-Reducing Thermophilic Bacterium Thermodesulfovibrio yellowstonii Strain DSM 11347T (Phylum Nitrospirae)

  Genome Announcements

  Here, we present the complete 2,003,803-bp genome of a sulfate-reducing thermophilic bacterium, Thermodesulfovibrio yellowstonii strain DSM 11347T.

• Halocins: Protein Antibiotics from Hypersaline Environments. In, Microbiology and Biogeochemistry of Hypersaline Environments, A. Oren, Ed.

  CRC Press

  To see text on Google Books: https://books.google.com/books?id=rBk1hHU1zx8C&lpg=PA297&ots=SLmV-ojmFp&dq=Halocins%3A%20Protein%20Antibiotics%20from%20Hypersaline%20Environments&pg=PA296#v=onepage&q&f=true

• Genome Sequence of a Sulfate-Reducing Thermophilic Bacterium, Thermodesulfobacterium commune DSM 2178T (Phylum Thermodesulfobacteria)

  Genome Announcements

  Here, we present the complete 2,003,803-bp genome of a sulfate-reducing thermophilic bacterium, Thermodesulfovibrio yellowstonii strain DSM 11347T.

• Halocins and Sulfolobicins: The Emerging Story of Archaeal Protein and Peptide Antibiotics

  Journal of Industrial Microbiology and Biotechnology

  Production of antibiotic peptides and proteins is a near-universal feature of living organisms regardless of phylogenetic classification. Bacteriocins (proteinaceous antimicrobials from the domain Bacteria) have been studied for over 75 years, and the eucaryocins (proteinaceous antimicrobials from the domain Eucarya) since the early 1960s. However, one domain of organisms, the Archaea, containing hyperthermophiles, extreme halophiles and the methanogens, is just beginning to be scrutinized for the production of peptide antibiotics. Production of archaeal proteinaceous antimicrobials (archaeocins) from extreme halophiles (halocins) is a nearly universal feature of the rod-shaped haloarchaea. Halocin activity is first detectable in culture supernatants at the beginning of the transition into stationary phase, concomitant with an induction of transcription of the structural gene. Halocins are diverse in size, consisting of proteins as large as 35 kDa and peptide "microhalocins" as small as 3.6 kDa. The 36 amino acids of microhalocin HalS8 are located in the interior of a 311-residue pro-protein from which they are liberated by an unknown mechanism. Microhalocins are hydrophobic and robust, withstanding heat, desalting and exposure to organic solvents. Unlike the peptide bacteriocins and the eucaryocins, microhalocins possess a large number of neutral residues and are not cationic, leaving their mechanism(s) of action mostly a mystery. While microhalocins affect a variety of haloarchaeal genera (kingdom Euryarchaeota), they also exhibit cross-kingdom toxicity, inhibiting or killing Sulfolobus species (kingdom Crenarchaeota). Finally, archaeocins also are produced by the hyperthermophile "Sulfolobus islandicus". These 20-kDa protein antibiotics are not excreted into the environment, but are associated with small particles apparently derived from the cell's S-layer.

• Purification and Characterization of Microhalocin R1 from Halobacterium salinarum GN101

  Ph.D. Dissertation, Northern Arizona University

• Isolation, sequence and expression of the gene encoding halocin H4, a bacteriocin from the halophilic archaeon, Haloferax mediterranei R4

  Journal of Bacteriology

  The first gene to encode a haloarchaeal bacteriocin (halocin H4) has been cloned and sequenced from Haloferax mediterranei R4. Both the signal sequence in the halocin H4 preprotein and the monocistronic halH4 gene have some unusual features. The physiology of halH4 expression reveals that although halH4 transcripts are present at low basal levels during exponential growth, halocin H4 activity first appears as the culture enters stationary phase. As halocin activity levels increase, so do transcript levels, but then activity levels decrease precipitously while transcript levels remain elevated.

• Genome Sequence of the Sulfate-Reducing Thermophilic Bacterium Thermodesulfovibrio yellowstonii Strain DSM 11347T (Phylum Nitrospirae)

  Genome Announcements

  Here, we present the complete 2,003,803-bp genome of a sulfate-reducing thermophilic bacterium, Thermodesulfovibrio yellowstonii strain DSM 11347T.

• Structural Comparison of Protein Phosphoserine and Phosphotyrosine Phosphatases

  Masters Thesis

• Halocins: Protein Antibiotics from Hypersaline Environments. In, Microbiology and Biogeochemistry of Hypersaline Environments, A. Oren, Ed.

  CRC Press

  To see text on Google Books: https://books.google.com/books?id=rBk1hHU1zx8C&lpg=PA297&ots=SLmV-ojmFp&dq=Halocins%3A%20Protein%20Antibiotics%20from%20Hypersaline%20Environments&pg=PA296#v=onepage&q&f=true

• Genome Sequence of a Sulfate-Reducing Thermophilic Bacterium, Thermodesulfobacterium commune DSM 2178T (Phylum Thermodesulfobacteria)

  Genome Announcements

  Here, we present the complete 2,003,803-bp genome of a sulfate-reducing thermophilic bacterium, Thermodesulfovibrio yellowstonii strain DSM 11347T.

• Halocins and Sulfolobicins: The Emerging Story of Archaeal Protein and Peptide Antibiotics

  Journal of Industrial Microbiology and Biotechnology

  Production of antibiotic peptides and proteins is a near-universal feature of living organisms regardless of phylogenetic classification. Bacteriocins (proteinaceous antimicrobials from the domain Bacteria) have been studied for over 75 years, and the eucaryocins (proteinaceous antimicrobials from the domain Eucarya) since the early 1960s. However, one domain of organisms, the Archaea, containing hyperthermophiles, extreme halophiles and the methanogens, is just beginning to be scrutinized for the production of peptide antibiotics. Production of archaeal proteinaceous antimicrobials (archaeocins) from extreme halophiles (halocins) is a nearly universal feature of the rod-shaped haloarchaea. Halocin activity is first detectable in culture supernatants at the beginning of the transition into stationary phase, concomitant with an induction of transcription of the structural gene. Halocins are diverse in size, consisting of proteins as large as 35 kDa and peptide "microhalocins" as small as 3.6 kDa. The 36 amino acids of microhalocin HalS8 are located in the interior of a 311-residue pro-protein from which they are liberated by an unknown mechanism. Microhalocins are hydrophobic and robust, withstanding heat, desalting and exposure to organic solvents. Unlike the peptide bacteriocins and the eucaryocins, microhalocins possess a large number of neutral residues and are not cationic, leaving their mechanism(s) of action mostly a mystery. While microhalocins affect a variety of haloarchaeal genera (kingdom Euryarchaeota), they also exhibit cross-kingdom toxicity, inhibiting or killing Sulfolobus species (kingdom Crenarchaeota). Finally, archaeocins also are produced by the hyperthermophile "Sulfolobus islandicus". These 20-kDa protein antibiotics are not excreted into the environment, but are associated with small particles apparently derived from the cell's S-layer.

• Purification and Characterization of Microhalocin R1 from Halobacterium salinarum GN101

  Ph.D. Dissertation, Northern Arizona University

• Isolation, sequence and expression of the gene encoding halocin H4, a bacteriocin from the halophilic archaeon, Haloferax mediterranei R4

  Journal of Bacteriology

  The first gene to encode a haloarchaeal bacteriocin (halocin H4) has been cloned and sequenced from Haloferax mediterranei R4. Both the signal sequence in the halocin H4 preprotein and the monocistronic halH4 gene have some unusual features. The physiology of halH4 expression reveals that although halH4 transcripts are present at low basal levels during exponential growth, halocin H4 activity first appears as the culture enters stationary phase. As halocin activity levels increase, so do transcript levels, but then activity levels decrease precipitously while transcript levels remain elevated.

• Genome Sequence of the Sulfate-Reducing Thermophilic Bacterium Thermodesulfovibrio yellowstonii Strain DSM 11347T (Phylum Nitrospirae)

  Genome Announcements

  Here, we present the complete 2,003,803-bp genome of a sulfate-reducing thermophilic bacterium, Thermodesulfovibrio yellowstonii strain DSM 11347T.

• Structural Comparison of Protein Phosphoserine and Phosphotyrosine Phosphatases

  Masters Thesis

• The Complete Genome Sequence of Hyperthermophile Dictyoglomus turgidum DSM6724™ Reveals a Specialized Carbohydrate Fermentor

  Frontiers in Microbiology

  The complete genome sequence of the chemoorganotrophic, extremely thermophilic bacterium, Dictyoglomus turgidum, which is a Gram negative, strictly anaerobic bacterium. D. turgidum and D. thermophilum together form the Dictyoglomi phylum. The two Dictyoglomus genomes are highly syntenic, and both are distantly related to Caldicellulosiruptor spp. D. turgidum is able to grow on a wide variety of polysaccharide substrates due to significant genomic commitment to glycosyl hydrolases, 16 of which were cloned and expressed in our study. The GH5, GH10, and GH42 enzymes characterized in this study suggest that D. turgidum can utilize most plant-based polysaccharides except crystalline cellulose. The DNA polymerase I enzyme was also expressed and characterized. The pure enzyme showed improved amplification of long PCR targets compared to Taq polymerase. The genome contains a full complement of DNA modifying enzymes, and an unusually high copy number (4) of a new, ancestral family of polB type nucleotidyltransferases designated as MNT (minimal nucleotidyltransferases). Considering its optimal growth at 72°C, D. turgidum has an anomalously low G+C content of 39.9% that may account for the presence of reverse gyrase, usually associated with hyperthermophiles As part of my role as a bacterial physiologist on the Tree of Life Project, I received special acknowledgment for Dictyoglomus turgidum DSM6724™ culture and cell preparation for sequencing DNA.

• Halocins: Protein Antibiotics from Hypersaline Environments. In, Microbiology and Biogeochemistry of Hypersaline Environments, A. Oren, Ed.

  CRC Press

  To see text on Google Books: https://books.google.com/books?id=rBk1hHU1zx8C&lpg=PA297&ots=SLmV-ojmFp&dq=Halocins%3A%20Protein%20Antibiotics%20from%20Hypersaline%20Environments&pg=PA296#v=onepage&q&f=true

• Genome Sequence of a Sulfate-Reducing Thermophilic Bacterium, Thermodesulfobacterium commune DSM 2178T (Phylum Thermodesulfobacteria)

  Genome Announcements

  Here, we present the complete 2,003,803-bp genome of a sulfate-reducing thermophilic bacterium, Thermodesulfovibrio yellowstonii strain DSM 11347T.

• Halocins and Sulfolobicins: The Emerging Story of Archaeal Protein and Peptide Antibiotics

  Journal of Industrial Microbiology and Biotechnology

  Production of antibiotic peptides and proteins is a near-universal feature of living organisms regardless of phylogenetic classification. Bacteriocins (proteinaceous antimicrobials from the domain Bacteria) have been studied for over 75 years, and the eucaryocins (proteinaceous antimicrobials from the domain Eucarya) since the early 1960s. However, one domain of organisms, the Archaea, containing hyperthermophiles, extreme halophiles and the methanogens, is just beginning to be scrutinized for the production of peptide antibiotics. Production of archaeal proteinaceous antimicrobials (archaeocins) from extreme halophiles (halocins) is a nearly universal feature of the rod-shaped haloarchaea. Halocin activity is first detectable in culture supernatants at the beginning of the transition into stationary phase, concomitant with an induction of transcription of the structural gene. Halocins are diverse in size, consisting of proteins as large as 35 kDa and peptide "microhalocins" as small as 3.6 kDa. The 36 amino acids of microhalocin HalS8 are located in the interior of a 311-residue pro-protein from which they are liberated by an unknown mechanism. Microhalocins are hydrophobic and robust, withstanding heat, desalting and exposure to organic solvents. Unlike the peptide bacteriocins and the eucaryocins, microhalocins possess a large number of neutral residues and are not cationic, leaving their mechanism(s) of action mostly a mystery. While microhalocins affect a variety of haloarchaeal genera (kingdom Euryarchaeota), they also exhibit cross-kingdom toxicity, inhibiting or killing Sulfolobus species (kingdom Crenarchaeota). Finally, archaeocins also are produced by the hyperthermophile "Sulfolobus islandicus". These 20-kDa protein antibiotics are not excreted into the environment, but are associated with small particles apparently derived from the cell's S-layer.

• Purification and Characterization of Microhalocin R1 from Halobacterium salinarum GN101

  Ph.D. Dissertation, Northern Arizona University

• Isolation, sequence and expression of the gene encoding halocin H4, a bacteriocin from the halophilic archaeon, Haloferax mediterranei R4

  Journal of Bacteriology

  The first gene to encode a haloarchaeal bacteriocin (halocin H4) has been cloned and sequenced from Haloferax mediterranei R4. Both the signal sequence in the halocin H4 preprotein and the monocistronic halH4 gene have some unusual features. The physiology of halH4 expression reveals that although halH4 transcripts are present at low basal levels during exponential growth, halocin H4 activity first appears as the culture enters stationary phase. As halocin activity levels increase, so do transcript levels, but then activity levels decrease precipitously while transcript levels remain elevated.

• Genome Sequence of the Sulfate-Reducing Thermophilic Bacterium Thermodesulfovibrio yellowstonii Strain DSM 11347T (Phylum Nitrospirae)

  Genome Announcements

  Here, we present the complete 2,003,803-bp genome of a sulfate-reducing thermophilic bacterium, Thermodesulfovibrio yellowstonii strain DSM 11347T.

• Structural Comparison of Protein Phosphoserine and Phosphotyrosine Phosphatases

  Masters Thesis

• The Complete Genome Sequence of Hyperthermophile Dictyoglomus turgidum DSM6724™ Reveals a Specialized Carbohydrate Fermentor

  Frontiers in Microbiology

  The complete genome sequence of the chemoorganotrophic, extremely thermophilic bacterium, Dictyoglomus turgidum, which is a Gram negative, strictly anaerobic bacterium. D. turgidum and D. thermophilum together form the Dictyoglomi phylum. The two Dictyoglomus genomes are highly syntenic, and both are distantly related to Caldicellulosiruptor spp. D. turgidum is able to grow on a wide variety of polysaccharide substrates due to significant genomic commitment to glycosyl hydrolases, 16 of which were cloned and expressed in our study. The GH5, GH10, and GH42 enzymes characterized in this study suggest that D. turgidum can utilize most plant-based polysaccharides except crystalline cellulose. The DNA polymerase I enzyme was also expressed and characterized. The pure enzyme showed improved amplification of long PCR targets compared to Taq polymerase. The genome contains a full complement of DNA modifying enzymes, and an unusually high copy number (4) of a new, ancestral family of polB type nucleotidyltransferases designated as MNT (minimal nucleotidyltransferases). Considering its optimal growth at 72°C, D. turgidum has an anomalously low G+C content of 39.9% that may account for the presence of reverse gyrase, usually associated with hyperthermophiles As part of my role as a bacterial physiologist on the Tree of Life Project, I received special acknowledgment for Dictyoglomus turgidum DSM6724™ culture and cell preparation for sequencing DNA.

• Halocins as Reporters for Identifying Stationary-specific Factors Involved in Transcription Initiation

  Gordon Research Conference on Archaea: Ecology, Metabolism and Molecular Biology, Proctor Academy, Andover, NH

  8/1-5/1999: Poster presenter and attendee