Triterpene glycosides from Schefflera octophylla.

In addition to 3-epi-betulinic acid, three triterpene glycosides were isolated from leaves of Schefflera octophylla. The structures of the glycosides have been determined as 28-O-[alpha-L-rhamnopyranosyl(1----4)-O-beta-D-glucopyranosyl(1----6)-be ta-D- glucopyranosides of 3 alpha-hydroxy-lup-20(29)-ene-23,28-dioic acid, 3 alpha,11 alpha- dihydroxy-lup20(29)-ene-23,28-dioic acid and 3-epi-betulinic acid by spectroscopic data and chemical transformations. The last two compounds were found for the first time in the plant kingdom.     

Canarion,ein neues naphthochinon aus Usnea canariensis

The structure of canarione, a new naphthoquinone from the lichens Usnea canariensis and U. hookeri was elucidated by UV, ¹H-NMR, ¹³C-NMR, mass spectrometry, and chemical degradation as 5,8-dihydroxy-2-methyl-4H-naphtho [2,3b]-pyran-4,6,9 (6H, 9H)- trione.     

Studies on the biosynthesis of 2-hydroxy-1,4-benzoxazin-3-one (HBOA) from 3-hydroxyindolin-2-one in Zea mays

The ring expansion of 3-hydroxyindolin-2-one to 2-hydroxy-1,4-benzoxazin-3-one (HBOA) was investigated by labelling experiments. Action of the cytochrome P450 enzyme BX4 from maize on 3-hydroxyindolin-2-one under an 18O2 atmosphere induced production of 2-hydroxy-1,4-benzoxazin-3-one in which the ring oxygen--but not the 2-hydroxy group of HBOA--is labelled. A mechanism for this transformation is proposed.     

8-Oxoerythrinine: An alkaloid from Erythrina brucei

The flowers of Erythrina brucei afforded, in addition to known compounds, a new erythrina alkaloid, 8-oxoerythrinine. Its structure was elucidated by spectroscopic investigations as well as by chemical transformations.     

The Intensity of Victimization: Associations with Children's Psychosocial Well-Being and Social Standing in the Classroom

The association between experienced victimization and students'' psychological and social adjustment depends on the intensity of victimization. We examined how frequency and multiplicity of victimization, and the number of bullies involved, account for differences in students’ psychosocial well-being and social standing in the classroom. Multilevel analyses were conducted on the control group of an intervention study among students in grades 3–6 of Dutch elementary schools (N = 2859 students from 124 classes and 33 schools; ages 8–12; 49.6% boys). It was found that victims of frequent and multiple victimization, and victims who were victimized by several bullies, had higher levels of psychosocial adjustment problems than victims of less frequent and non-multiple victimization, and victims with only one bully. Moreover, these more severe victims turned out to be least accepted and most rejected among their classmates. The findings illustrate that it can be fruitful to use several measures of victimization so that (differences in) adjustment problems can be better understood. Moreover, the results suggest that it is important to find out who is victimized, in what ways, and by whom. Anti-bullying interventions should provide resources to do this.     

Molecular and genetic characterization of an ornithine decarboxylase-deficient Chinese hamster cell line.

The ornithine decarboxylase (ODC)-deficient Chinese hamster ovary (CHO) cell line C55.7 has normal amounts of ODC mRNA with very low amounts of immunologically detectable ODC protein, suggesting a structural mutation; however, 5-azacytidine treatment leads to phenotypical reversion (Steglich, C., and Scheffler, I. E. (1985) Somat. Cell Mol. Genet. 11, 11-23). We have demonstrated by chemical cleavage a single base mismatch in DNA heteroduplexes composed of wild-type and mutant cDNA strands. DNA sequencing showed that the mutant phenotype results from an aspartate-glycine substitution at amino acid 381 of the protein. When 5-azacytidine-revertant cell lines were selected for resistance to alpha-difluoromethylornithine, the resulting amplified ODC gene was structurally indistinguishable from the wild type gene. These results suggested the existence of a single active ODC locus in CHO cells. Using the methylation-sensitive restriction endonucleases AvaI and HpaII, we found evidence for two differentially methylated alleles in wild type, ODC-deficient and alpha-difluoromethylornithine-resistant cells. One of the alleles appeared completely inactivated by hypermethylation but could be reactivated by demethylation in spontaneous or 5-azacytidine-induced revertants.     

Expression of mRNA for glucose transport proteins in jejunum, liver, kidney and skeletal muscle of pigs

Although pigs are adapted to starch-rich diets and have high turnover rates of glucose, very scarce information is available on the molecular basis of glucose transport. Therefore, the present study attempted a systematic screening for the presence of mRNA of glucose transport proteins in main organs of glucose absorption, production and conservation. From the members of the solute carrier family SLC5A (sodium glucose cotransporter), the porcine jejunum was positive for SGLT1 and SGLT3, but also contained detectable levels of SGLT5. Liver contained SGLT1, SGLT5, traces of SGLT3 and, in one of five pigs, SGLT2. Kidney contained SGLT1, SGLT2, SGLT3, SGLT5 and hardly detectable levels of SGLT4. Skeletal muscle showed weak signals for SGLT3 and SGLT5. Screening for members of the SLC2A family (facilitated glucose transporter) in intestine revealed the presence of mRNA for GLUT1, GLUT2, GLUT5, GLUT7 and GLUT8, while GLUT3, GLUT4, GLUT10 and GLUT11 were also detectable. The liver contained GLUT1, GLUT2 and GLUT8 mRNA, while GLUT3, GLUT4, GLUT5, GLUT10 and GLUT11 were poorly detectable. The kidney was positive for GLUT1, GLUT2, GLUT5, GLUT8 and GLUT11, but traces of GLUT3, GLUT4 and GLUT10 could also be detected. Skeletal muscle had the strongest signal for GLUT4, while GLUT1, GLUT3, GLUT5, GLUT8, GLUT10 and GLUT11 showed weak signals. A total of 12 unique partial cDNA sequences were submitted to GenBank. In conclusion, this study provides molecular insight into the organ-specific expression of glucose transporters in pigs and thus sheds light on the way of glucose handling in this omnivorous species.     

Schizonellin A and B,new glycolipids from Schizonella melanogramma

Two new glycolipids, schizonellin A and B, were isolated from cultures of the smut fungus Schizonella melanogramma. Their structures were elucidated by chemical degradation and spectroscopic methods. The schizonellins are active against Gram-positive bacteria, as well as against some Gram-negative bacteria and some fungi. DNA-, RNA- and protein-syntheses in Ehrlich carcinoma ascitic cells are inhibited simultaneously after addition of the schizonellins. Strong haemolytic action on bovine erythrocytes was observed.