Pollen of a male-sterile mutant of Arabidopsis thaliana isolated from a T-DNA insertion pool is not effectively released from the anther locule.

We have isolated a male-sterile mutant from a pool of T-DNA insertional lines of Arabidopsis thaliana generated by an in planta transformation procedure [Chang et al. (1994) Plant J. 5: 551]. Pollen in this mutant is not effectively released from anther locules after cleavage of the stomium. Most mutant pollen grains are round, in contrast to the tricolpate wild-type pollen, and some pollen grains show an abnormal surface structure. Manually released mutant pollen grains are not fertile and show defects in pollen tube germination in vitro. Genetic analysis disclosed that this lesion is due to a single recessive nuclear mutation located on chromosome 3 closely linked to the gll locus. The mutation locus is tightly linked to the inserted T-DNA.

Antiulcerogenic compounds isolated from Chinese cinnamon.

Two active compounds that prevent serotonin-induced ulcerogenesis in rats were isolated from Chinese cinnamon (the stem bark of Cinnamomum cassia) and identified as 3-(2-hydroxyphenyl)-propanoic acid and its O-glucoside. The former compound, administered orally or parenterally to rats at a remarkably low dose (40 micrograms/kg body weight), also inhibited gastric ulcers induced by the other ulcerogens such as phenylbutazone, ethanol, and water immersion stress, although it failed to prevent indomethacin-induced ulcers. Pharmacological studies have shown that 3-(2-hydroxyphenyl)-propanoic acid hardly inhibited the secretion of gastric acid, but promoted the gastric blood flow. These results suggest that the antiulcerogenic effect of this compound is probably attributable to the potentiation of defensive factors through the improvement of the circulatory disorder and gastric cytoprotection.

Preclinical safety evaluation of the nadolol/bendroflumethiazide combination in mice, rats, and dogs.

Nadolol, a beta-adrenergic antagonist, and bendroflumethiazide, a thiazide diuretic, were administered orally alone and in combination to animals in acute and 6-month toxicity studies and in a rat teratology study. The two drugs in combination showed no evidence of potentiation of acute toxicity in mice. Nadolol and/or bendroflumethiazide were administered orally to rats at daily doses of 1000 or 160 mg/kg of nadolol and 125 or 20 mg/kg of bendroflumethiazide and to dogs at daily doses of 160 or 40 mg/kg of nadolol and 20 or 5 mg/kg of bendroflumethiazide for 6 months. The two drugs, alone and in combination, caused only minor changes in clinical-laboratory tests and no major gross or histopathologic changes. Many of the changes noted were expected pharmacologic effects of the individual agents. The drugs, alone or in combination, produced no evidence of embryotoxicity, fetotoxicity, or teratogenicity in rats. The results of these studies indicate that nadolol and bendroflumethiazide have a low order of toxicity individually, and when given in combination show no additional or potentiated toxicity.