558 PATENT ABSTRACTS

having a density in the range of from 1.105 to 1.110 g/mL and the second layer having a density in the range of from 1.075 to 1.085 g/mL, and maternal granulocytes are collected at an inter- face between a gel layer having a density in the range of from 1.115 to 1.125 g/mL and a layer having a density in the range of from 1.105 to 1.110 g/mL. This allows separation of fetal cells for testing from the maternal blood rather than the placenta or amniotic fluid, reducing the risk of sample collection and facilitating routine testing of fetal cells for evidence of genetic defects.

5275940

P R O C E S S F O R P R O D U C I N G L - T R Y P T O P H A N B Y C U L T U R I N G

A C O R Y N E B A C T E R I U M G L U T A M I C U M M U T A N T

Kuniki Kino, Kazuhiro Furukawa, Yasuhir Tomiyoshi, Yoshiyuki Kuratsu, Hofu, Japan as- signed to Kyowa Hakko Kogyo Co Ltd

Disclosed is a process for producing L- tryptophan which comprises culturing in a medium a microorganism belonging to the genus Corynebacterium or Brevibacterium having resistance to an aminoquinoline derivative or a phenothiazine derivative and an ability to pro- duce L-tryptophan until L-tryptophan is ac- cumulated in the culture and recovering L- tryptophan therefrom.

5275942

M A M M A L I A N C E L L - B A S E D D N A L I B R A R I E S

Jean-Michel Vos assigned to The University of North Carolina at Chapel Hill

A recombinant plasmid useful for the produc- tion of large-insert, stably maintained, episomes in mammalian cells is disclosed, along with cells, DNA libraries, and methods of using the same. The plasmid comprises a lymphotrophic herpes virus segment (e.g., an Epstein-Barr virus seg- ment) containing an origin of plasmid replica- tion (oriP) and a heterologous insert segment linked to the lymphotrophic herpes virus seg- ment. The heterologous insert segment has a length of at least 100 kilobases. In a preferred embodiment, the lymphotrophic herpes virus segment is capable of producing infectious

virions in a suitable host cell, and the lympho- trophic herpes virus segment has regions deleted so that the recombinant plasmid retains the cap- ability of producing infectious virions in the host.

5276062

H P L C A V I D I N M O N O M E R A F F I N I T Y R E S I N

Ferdinand C Haase assigned to Rohm and Haas Company

Novel, improved ligand-containing media, a method of preparation and use in the production of peptides, proteins, and the like, by chromatographic separation, and more specifically media having permanently attached via a covalent bond to an inert solid substrate an avidin polypeptide ligand in the dissociated renatured form which reversibly binds to certain molecules such as proteins, peptide, nucleotides, oligonucleotides, and the like and to other molecules which bind to avidin via biotinylation or by way of their secondary/tertiary micro- molecular structures.

5276159

D Y N E M I C I N A N A L O G S : S Y N T H E S E S , M E T H O D S O F

P R E P A R A T I O N A N D U S E

Adrian Smith, Chan-Ko Hwang, Sebastian V Wendeborn, Kyriacos Nicolaou, Erwin P Schreiner, Wilhelm Stahl, Wei-Min Dai, Peter E Maligres, Toshi Suzuki, Bishops Stortford, CA, United Kingdom assigned to The Scripps Research Institute

A fused ring system compound is disclosed that contains an epoxide group on one side of the fused rings and an enediyne macroeyclic ring on the other side of the fused rings. The compounds have DNA-cleaving, antimicrobial and tumor growth-inhibiting properties. Chimeric com- pounds having the fused ring system compound as an aglycone bonded to (i) a sugar moiety as the oligosaccharide portion or (ii) a monoclonal antibody or antibody combining site portion thereof that immunoreacts with target tumor cells are also disclosed. Compositions containing a compound or a chimer are disclosed, as are methods of preparing a compound.