Biosystematic studies onDisporum (Liliaceae-Polygonatae)

Both the floral biology and morphometrics of two Japanese species of AsianDisporum (sectionEudisporum) are presented. These two species,D. sessile andD. smilacinum, represent extremes in both floral morphology and divergence in pollination within the section. The inverted flowers ofD. sessile have an elongate floral tube formed by the imbrication of the oblanceolate tepals. The tepal bases are modified into well developed, saccate nectaries. The stamens have rigid, vertical filaments which tightly encircle the ovary-style axis, and extrorse anthers located within a floral cavity which can accommodate a large pollinator (cross-pollination). The stigma is exserted and the depth of its cleft formation constant.D. smilacinum, in contrast, has an open, nodding campanulate flower with lanceolate tepals which have only shallow nectaries at their bases. The stamens have widely divergent filaments with versatile anthers that have laterally introrse dehiscence (wind and/or self-pollination). The depth of the stigma cleft is variable. For both species, the pattern of differential UV absorption and reflectance is similar. It is suggested on morphological grounds and by pollinator observation, thatD. sessile with a high energy flower requiring specialized visitors represents a more advanced condition than that observed inD. smilacinum, which is more generalized and primitive. Seasonal herbivore pressure on the tepal nectaries ofD. sessile is discussed in relation to its pollination.     

Deterrent effect of soybean meal on feeding of the silkworm, Bombyx mori

The occurrence of a factor in soybean which deters feeding of the silkworm was demonstrated. The deterrent was not extractable with ether or ethanol, but was extracted with 90% ethanol or hot water. Preliminary experiments showed that the deterrent was adsorbed on charcoal, but neither on activated alumina nor in a steam distillate. Autoclaving did not inactivate the deleterious effect. A crude extract of the deterrent showed a marked negative feeding response by including 0·4 mg/g of the dry diet.Inclusion of the crude extract in the diet retarded the growth of larvae, whereas larvae grew well when receiving the 90% ethanol-washed meal. Feeding response for various soybean meals and proteins were compared, and better larval growth has generally obtained when the feeding response was more positive. It is, however, inconclusive whether or not the deleterious principle possesses some physiologically toxic effect.The feeding behaviour of newly hatched larvae was observed in the presence of favourable and/or unfavourable diets, and a brief discussion is made concerning the feeding behaviour of this insect.     

Biosystematic studies inErythronium (Liliaceae-Tulipeae)

The floral biology ofErythronium japonicum has been studied from two approaches: a reinvestigation of its floral morphology and a pollinator case history. The perianth, differentiated into a sepal and petal cycle, has a tubular, but free arrangement basally around a slightly stipitate ovary. The two cycles of stamens with dimorphic filaments are positioned by the differently lobed auricles of the mature sepals and petals. These auricles also form a trap-lid mechanism for the inverted nectary which also has passageways. The perianth parts are highly UV absorbant due to the presence of flavonoids. This pattern contrasts strikingly with the purple trident basal guide lines so prominent in the visible spectrum. The weakly protandrous flowers also have exserted styles, thus functioning to exclude its own pollen and insure outbreeding. These floral adaptations are related specifically to the pollination behavior ofXylocopa appendiculata, and in general to the floral evolution within the genusErythronium. This work was supported in part by the U.S.-Japan Cooperative Science Program Grant GF-41367 and Grant-in-Aid No. 934053 from the Ministry of Education, Japan.     

The design and synthesis of a new tumor-selective fluoropyrimidine carbamate, capecitabine

To identify an orally available fluoropyrimidine having efficacy and safety profiles greatly improved over those of parenteral 5-fluorouracil (5-FU: 1), we designed a 5-FU prodrug that would pass intact through the intestinal mucisa and be sequentially converted to 5-FU by enzymes that are highly expressed in the human liver and then in tumors. Among various N4-substituted 5'-deoxy-5-fluorocytidine derivatives, a series of N4-alkoxycarbonyl derivatives were hydrolyzed to 5'-deoxy-5-fluorocytidine (5'-DFCR: 8) specifically by carboxylesterase, which exists preferentially in the liver in humans and monkeys. Particularly, derivatives having an N4-alkoxylcarbonyl moiety with a C4-C6 alkyl chain were the most susceptible to the human carboxylesterase. Those were then converted to 5'-deoxy-5-fluorouridine (5'-DFUR: 4) by cytidine deaminase highly expressed in the liver and solid tumors and finally to 5-FU by thymidine phosphorylase (dThdPase) preferentially located in tumors. When administered orally to monkeys, a derivative having the N4-alkoxylcarbonyl moiety with a C5 alkyl chain (capecitabine: 6) The highest AUC and Cmax for plasma 5'-DFUR. In tests with various human cancer xenograft models, capecitabine was more efficacious at wider dose ranges than either 5-FU or 5'-DFUR and was significantly less toxic to the intestinal tract than the others in monkeys.     

Secretory and continuous expression of Aspergillus niger glucose oxidase gene in Pichia pastoris

We proposed a yeast transformant cell incorporating the Aspergillus niger glucose oxidase gene (GOX gene), which is capable of constitutively as well as secretory expression. The GOX gene has been cloned in this study. This conclusion is based on the following: first, the ligated DNA determined by electrophoresis, was a 1489-1882bp fragment, close to the size of glucose oxidase (GOD), which is 1818bp. Secondly, the single open reading frame encoded a protein of 605 amino acids. Thirdly, secreted GOD recombinant proteins in the culture supernatants of the GOX gene transformant migrated as a single band in SDS-PAGE with an apparent molecular mass of between 75,000 and 100,000 Da, which is glycosylated GOD by the Pichia pastoris X-33 host machinery during the secretion process. Finally, the clones were cultured and secreted a protein, which possessed the GOD activity of catalyzing beta-d-glucose oxidation. With regard to the pH characteristics, the activity was more than 80% of the maximum activity in the range between pH 5 and pH 7. As for the temperature characteristics, the activity was not less than 92% of the maximum in the temperature range between 10 and 45 degrees C. The GOX gene transformant was able to maintain the GOD enzyme activity and produce recombinant GOD continuously for at least 2 weeks.     

Ultrastructure of perivascular amyloid fibrils in Alzheimer’s disease

Perivascular amyloid fibrils in the brains of patients with Alzheimer's disease have been examined by electron microscopy. The amyloid fibrils showed a hollow rod structure and consisted of globular substances. Each turn appeared to be composed of five globular subunits. These findings coincide with the ultrastructure of amyloid fibrils obtained from replicas made by a rapid freezing method.     

Pyridoxine stimulates filaggrin production in human epidermal keratinocytes

Molecular Biology Reports - Pyridoxine (PN), one of the vitamers of vitamin B6, plays an important role in the maintenance of epidermal function and is used to treat acne and rough skin. Clinical...