A high efficiency technique for the generation of transgenic sugar beets from stomatal guard cells.

An optimized protocol has been developed for the efficient and rapid genetic modification of sugar beet (Beta vulgaris L.). A polyethylene glycol-mediated DNA transformation technique could be applied to protoplast populations enriched specifically for a single totipotent cell type derived from stomatal guard cells, to achieve high transformation frequencies. Bialaphos resistance, conferred by the pat gene, produced a highly efficient selection system. The majority of plants were obtained within 8 to 9 weeks and were appropriate for plant breeding purposes. All were resistant to glufosinate-ammonium-based herbicides. Detailed genomic characterization has verified transgene integration, and progeny analysis showed Mendelian inheritance.

Total colonic aganglionosis initially diagnosed in an adolescent.

A 12-yr-old girl was admitted for evaluation of a 5-wk history of increasing abdominal pain. She also reported a history of constipation since birth requiring chronic laxative use. Occasional bouts of abdominal distention and vomiting resulted in dehydration necessitating hospitalization. Two previous laparotomies had identified an apparent obstructing angulation of the ascending colon. Rectal biopsy specimens obtained on this admission failed to reveal any ganglion cells. Sequential biopsy specimens of the entire colon obtained at laparotomy also failed to reveal any ganglion cells. Ganglion cells were found in the distal ileum. A total colectomy was performed. Three previously reported cases of total colonic aganglionosis initially diagnosed in older patients are reviewed. Similarities included nonspecific radiographic findings, a history of constipation since birth, and initial laparotomies revealing spurious causes of bowel obstruction.