A 13-week oral dose subchronic toxicity study of gardenia yellow containing geniposide in rats.

Gardenia yellow powders A, B and C, containing geniposide at 0.284%, 0.938% and 2.783%, respectively, were administered orally to male and female SD rats as 3% feed admixtures for 13-weeks to evaluate any potential toxicity. Mean geniposide intake values were 5.72, 18.9 and 56.3mg/kg/day in groups receiving these feed admixtures, respectively. All animals survived the duration of the study. The following findings were evident in the gardenia yellow C group: chromatouria, slightly increased plasma total bilirubin, blackish brown discoloration of the kidneys and liver, brown pigments in the proximal tubular epithelium of the kidneys. Slightly increased plasma total bilirubin was considered to be due to interference of metabolite of geniposide with the system of measurement and not to be a toxic effect since there were no related changes in histopathology of the liver or in any blood chemistry parameters. Other findings were limited to pigmentations or discolorations attributable to metabolites of geniposide. No treatment-related effects were evident on body weight, food consumption, ophthalmology, hematology or organ weights in any group. Therefore, it was concluded that 3-month ingestion of the gardenia yellow powder containing geniposide at 2.783% (approximately 60 mg/kg/day as geniposide intake) does not cause any severe toxic effects.

Convulsant action of systemically administered glutamate and bicuculline methiodide in immature rats.

Developmental changes of transport of drugs into the brain play an important role in ontogenetic neuropharmacology. Two convulsant drugs with different mechanisms of action (glutamate and bicuculline methiodide) were chosen to demonstrate these changes in developing rats. High dose of glutamate (4 g/kg i.p.) induced both minimal (predominantly clonic) and generalized tonic-clonic seizures in rat pups 7, 12, and 18 days old. In contrast, seizures were only exceptionally observed in 25 and 90 days old animals. Bicuculline methiodide was administered in a dose of 2 or 20 mg/kg i.p. The first sign of bicuculline methiodide action in all age groups was represented by automatisms, a symptomatology never seen after bicuculline hydrochloride administration. Minimal seizures were induced in 12-day-old and in a few 18-day-old and adult rats. Generalized seizures were common after the higher dose of bicuculline methiodide in 7- and 12-day-old rat pups, seldom in 18-day-old ones and never seen in 25-day-old and adult animals. Both glutamate and bicuculline methiodide enter the brain in immature rats but the mechanisms are probably different - glutamate is transported actively through the blood-brain barrier whereas no similar system is known for bicuculline methiodide.

bor1-1, an Arabidopsis thaliana mutant that requires a high level of boron.

bor1-1 (high boron requiring), an Arabidopsis thaliana mutant that requires a high level of B, was isolated. When the B concentration in the medium was reduced to 3 microM, the expansion of rosette leaves was severely affected in bor1-1 but not in wild-type plants. In a medium containing 30 microM B the mutant grew normally but showed female sterility, whereas the wild type was able to set seeds. These defects of the bor1-1 mutant were not detected with supplementation of 100 microM B. In vivo concentrations of B in bor1-1 mutants were lower than those of the wild type, especially in the inflorescence stems. Tracer experiments using 10B suggested that the mutant has defects in uptake and/or translocation of B. The mutation was mapped on the lower arm of chromosome 2.

Expression of a gene specific for iron deficiency (Ids3) in the roots of Hordeum vulgare.

To clone genes required for the synthesis of mugineic acid (MA) or for the transport of Fe(III)-MA, a lambda ZAPII cDNA library was constructed from poly(A)(+)-RNA isolated from Fe-deficient barley roots. The cDNA library was then used for differential screening of barley roots that had been grown in the presence and absence of iron. Seven clones that hybridized specifically to the probe for Fe deficiency were selected. One clone, presumably encoding a full-length mRNA, as deduced from Northern hybridization, was sequenced. The clone consisting of 1685 nucleotides encoded a putative protein of 169 amino acids and an M(r) of 18704. The gene was specifically expressed in the roots of iron-deficient barley. A search for homologies in a protein database (NBRF) revealed that the predicted protein product has a functional peptide domain that resembles that of 2-oxoglutarate-dependent dioxygenases.