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We investigated five penicillin derivatives that are popularly used for transformation experiments with Agrobacterium rhizogenes?penicillin G, carbenicillin, ampicillin, amoxicillin and cephalexin?for their effects on the growth and morphology of Beta vulgaris, Capsicum annuum and Glehnia littoralis roots. Attention was given to the relationship between their chemical structures and functions. Ampicillin was found to stimulate root elongation but inhibit root branching, whereas carbenicillin inhibited root elongation but promoted root branching. Root cultures were also exposed to hydrolyzed products of these antibiotics?i.e. phenylmalonic acid (PM), phenylglycine and 6-aminopenicillanic acid (6-APA): PM inhibited root elongation the most, while root elongation was supported best by 6-APA. These results indicate that both the side chains and the major component of penicillin derivatives affect root development and that the nature of the side chains is responsible for the responses. Ampicillin but not carbenicillin was used in subsequent experiments described herein to eliminate bacteria and to support root growth of transformants of the recalcitrant plants. [ABSTRACT FROM AUTHOR]

In this article, we report the experimental synthesis of reactive polymer microspheres of poly( p-hydroxycinnamic acid). Enzyme-catalyzed polymerization of poly( p-hydroxycinnamic acid) using horseradish peroxidase as a catalyst and hydrogen peroxide as an oxidant took place in a mixture solution of methanol and phosphate buffer solution; it was found that the fraction of methanol in the mixture solution strongly affected the yield of powdery polymer materials. The chemical structure of the polymers was characterized by 1H-NMR and FT-IR spectroscopies, and the molecular weight was measured by gel permeation chromatography. The 1H-NMR chart of the obtained polymer was almost the same as that of the monomer; FT-IR spectra indicated the existence of carboxyl groups. The weight-average molecular weight of the soluble part in tetrahydrofuran was found to be 1,451. Dispersion polymerization of p-hydroxycinnamic acid was carried out in a mixture solution of methanol and phosphate buffer solution by adding a dispersion stabilizer. Of the several such polymers tested, poly(vinyl alcohol) was found to be the most effective in producing reactive poly( p-hydroxycinnamic acid) microspheres. [ABSTRACT FROM AUTHOR]

In order to explore a possibility that the custom of drinking green tea infusion is efficacious for reducing the carcinogenic risk of environmental exposure to pentachlorophenol (PCP), we examined the effects in a hepato- and cholangiocarcinogenesis model in mice exposed to diethylnitrosamine (DEN). In the first experiment, groups of 15 male mice were initially treated with DEN at a dose of 20 p.p.m. in the drinking water for the first 8 weeks followed by a 4 week recovery interval by PCP at concentrations of 0 (basal diet), 300 or 600 p.p.m. in the diet for 23 weeks. Further groups of animals were treated with DEN and PCP in the same manner and received 2% green tea infusion (GT) instead of the drinking water from week 10 until death. PCP exposure at the high dose promoted DEN-induced hepatocarcinogenesis, and also caused progression of cystic hyperplasias of the intrahepatic bile ducts to cholangiocellular tumors. Co-administration of GT was able to prevent the increases of incidences and multiplicities of DEN-induced hepatocellular tumors and also arrest the progression of cholangiocellular tumors. In the second experiment, co-treatment with GT in the drinking water from 1 week before 300 or 600 p.p.m. PCP treatment in the diet to the end of the experiment at week 3 in B6C3F1 male mice suppressed increases of serum ALT activities, 8-oxodeoxyguanosine levels in liver DNA and bromodeoxyuridine labeling indices of hepatocytes and intrahepatic biliary epithelial cells induced by PCP. These findings suggest that regular intake of green tea may reduce the carcinogenic risk posed by an environmental pollutant, PCP, presumably due to effects on oxidative stress. [ABSTRACT FROM AUTHOR]