United States Biochemical New Source for T4 Polynucleotide Kinase

USB now uses an overproducing clone of the T4 gene to produce Polynucleotide Kinase. The purification is simplified, yielding larger quantities of enzyme than traditional methods, and the enzyme produced isvirtu- ally 100% pure, with no contaminating RNAase or DNAase. For more information contact: United States Biochemical Co. at (800) 321-9322.

Oncor Probe Count

Oncor, Inc. announces a new product for probe tech- nology. Probe Count *m is a small bench top instru- ment for counting 32P-labeled DNA or RNA probes. The low cost counter uses standard plastic tubes, does not require counting reagents, and exhibits reproduc- ible counts at lOs-10s dpmlug. For more information contact: Oncor, Box 870, Gaithersburg, MD 20877, (301) 983-3500.

Bethesda Research Labs New Frozen Competent pUC Host

E. coli DH5a (recAL,endAL,cp80dlacZAMl5) produces blue-white colonies for clone selection following trans- formation by pUC plasmids. BRL Frozen Competent Cells, E. coli DHSa, transform at much higher effi- ciency (>l x 108 transformantslug monomer pUCl9 DNA) than the traditional pUC hosts JM83 and TBl and are readily transformed by large plasmids with en- donuclease l-free background. Simply thaw and use; unused cells can be refrozen without loss of efficiency. For more information contact: Bethesda Research Laboratories, 8717 Grovemont Circle, PO. Box 8009, Gaithersburg, Maryland 20877, (301) 840-8000 or (800) 838-8992.

Genzyme Enzymes for Glycoprotein Research

Genzyme announces Endoglycosidase F and CMP: NANA-Gal8 (1,4)GIcNAcaP,bSialyltransferase. a-2-8- sialyltransferase adds sialic acid to the Gal 8 (1,4)- GlcNAc structure found on asparagine-linked com- plex oligosaccharides. The enzyme can be used as a probe for this structure on purified glycoproteins or on the surface of intact cells. For more information con- tact: Genzyme, 75 Kneeland Street, Boston, MA 02111, (800) 332-1042.