Philip Youderian . HYPERLINK

Department of Microbiology, Molecular Biology, and Biochemistry.University of Idaho.Moscow, Idaho 83844.(208) 885-0571 (office).(208) 885-7161 (lab).(208) 885-6518 (fax).
2. Recent publications:..Magrini, Vincent , Daniel Salmi, David Thomas, Stephen K. Herbert, Patricia L. Hartzell, and Philip Youderian. 1997. Temperate Myxococcus xanthus phage Mx8 encodes a DNA adenine methylase, Mox. J. Bacteriol. 179:.4254-4263...Salmi, Daniel, Vincent Magrini, Patricia L. Hartzell and Philip Youderian. 1998. Genetic determinants of immunity and integration of temperate Myxococcus xanthus phage Mx8. J. Bacteriol. 180: 614-621.
Salmi, Daniel, Chad Creighton, Michael L. Storms and Philip Youderian. 1998. Temperate Myxococcus xanthus phage Mx8 integrase catalyzes the reversible, covalent modification of its own coding sequence to regulate its specific activity. J. Bacteriol. submitted.

Weimer, Robby M., Chad Creighton, Angela Stassinopoulos, Philip Youderian, and Patricia Hartzell. 1998. A chaperone in the HSP70 family controls the production of extracellular fibrils in Myxococcus xanthus. J. Bacteriol, submitted...Creighton, Chad, Vincent Magrini, David White, Patricia L. Hartzell, and Philip Youderian. 1998. The aadA gene of plasmid R100 confers resistance to spectinomycin and streptomycin in Myxococcus xanthus. J. Bacteriol,.submitted.

Youderian, Philip. 1998. Bacterial motility: secretory secrets of gliding bacteria. Curr. Biol., in press.

Youderian, Philip, Matthew C. Lawes, Chad Creighton, Jessica C. Cook and Milton H. Saier, Jr. 1998. Mutations that confer resistance to 2-deoxyglucose reduce the specific activity of hexokinase from Myxococcus xanthus. Mol. Microbiol, submitted...3. Research interests:.
Mx8: The sequence of the Mx8 genome is now about 70% complete, and closure should occur within the year. We are completing studies on its mechanism of superinfection immunity, which appears to be regulated by a heterodimeric repressor in the b-ZIP family of DNA-binding proteins.

Hexose catabolism: We have identified a hexokinase in M. xanthus, and have initiated the detailed study of its kinetics, as well as those of E. coli glucokinase. Both enzymes are inhibited by glucosamine and N-acetylglucosamine, and we are investigating whether these hexoses may be alternate substrates. In addition, we have found that whereas the M. xanthus enzyme is inhibited by 2-deoxyglucose, the E. coli enzyme is stimulated by this hexose analogue, and we are exploring its allosteric regulation, oligomerization state, etc. Currently, we are in the process of purifying the M. xanthus enzyme to homogeneity from 40 liters of wild-type cells, so that we can clone its structural gene using reverse genetics, and overproduce and purify large amounts of the protein for detailed mechanistic studies.

Gluconeogenic anabolism: .We have cloned the M. xanthus genes for glutamine fructose-6-phosphate transamidase (gfaA and gfaB), the enzyme that catalyzes the first committed step in hexosamine biosynthesis, and are studying their differential regulation in response to development. This enzyme controls the flow of carbon into the major hexosamine building blocks of the spore-coat polysaccharides. Like R. meliloti, M. xanthus appears to make both vegetative and development-specific forms of this key enzyme. In collaboration with Bernard Badet, we are also exploring why this enzyme is the only glutamine-dependent transamidase that cannot use ammonia as an amido-donor.

Smaller puzzles: (Ion transport) Using the PCR, we have fortuitously cloned the helA gene from M. xanthus, and a portion of the arsenite antiporter/ATPase operon. We are exploring how these transport systems are important for the physiology of M. xanthus, which as a soil microorganism, must exclude these nasty chemicals it encounters in soil microenvironments.
(Secreted nuclease) As part of my continuing work with Trish on the sglK story, we are characterizing a gene nanA upstream of the two genes encoding histone-like repressors of fibril production, which, in turn, lie immediately upstream of the grpS-sglK operon. We would like to know what role the secreted nuclease it encodes plays in the M. xanthus pathway of nucleotide salvage.

The Myxococcus xanthus genome: In collaboration with Ron Gill, we have taken the cosmid library of M. xanthus, moved it into my beloved Salmonella typhimurium using phage P1, and have shown that we can cross cosmid inserts onto phage P22. We are in the process of developing a high-throughput strategy for the mutagenesis and sequencing of cosmid inserts, starting with two 35 kb P22 subclones of the dsp and rfb (O-antigen) loci, in collaboration with John Downard and Heidi Kaplan, and our sequencing support group led by Greg Buck and Greg Meyers at Commonwealth Biotechnologies, Inc. We expect to complete the ordered, overlap cosmid map of M. xanthus by mid-September. Also, we will have about 300 pools of mutant cosmids carrying selectable insertions in every M. xanthus gene that can be crossed onto the M. xanthus genome for functional analysis available for general use by October. We have obtained approval from the NIH to submit a $1.5 million proposal to complete the M. xanthus genome sequence, and with NIH support, we project a 3-year time-scale for completion. Sequence and mutant data will be posted monthly on the Myxo web site, starting in October, as we progress in our efforts.

4. Lab news:..a. Vince is looking for a post-doctoral position starting in June of 1999, and wants to stay in the Myxo field. He has produced 4 publications in the past four years, and is likely to have several more before he leaves..
b. Matthew Lawes has just joined our lab as a postdoctoral fellow. He comes with the training to use the awesome power of Salmonella and P22 genetics to sequence the M. xanthus genome.
.c. I am giving three talks at the Chilean Society for Microbiology meeting in July, and spreading the good news about Myxo in Santiago, where I look forward to spending a sabbatical in two years (after sequencing the Myxo genome, por supuesto.) .