On the mode of biodegradation of cinnamic acids by Colletotrichum gloeosporoides: A direct access to 4-vinylphenol and 2-methoxy-4-vinylphenol

The mode of transformation by growing cultures of Colletotrichum gloeosporoides of C-6-C-3, unsaturated cinnamic acids 1, a-f depends upon the pattern of the oxygen substitution in the aromatic ring; from 1b and 1d are exclusively obtained upon decarboxylation the C-6-C-2 vinyl phenols 2b and 2d. whereas in the remaining instances the C-6-C-3 educts 3–5 formed by reduction are prevalent     

1,3,7-Trimethylxanthine,an allelochemical from seeds ofCoffea arabica: Some aspects of its mode of action as a natural herbicide

Summary Certain aspects of selective toxicity of 1,3,7-trimethylxanthine (1,3,7-T), a natural herbicide, were studied inPhaseolus mungo andAmaranthus spinosus. Treatment of seeds ofA. spinosus with 1,3,7-T (sub-lethal concentration) caused a marked decrease (29.5%) in amylase activity. Kinetic studies with respect to substrate saturation and Km values as well asin vitro treatments of the cell-free enzyme indicated no effect on its catalytic property. The inhibitory effect of 1,3,7-T on amylase activity could not be counteracted with treatments of GA₃. A general biochemical analysis revealed that the starch/sugar ratio increased in the seedlings grown from treated seeds. Analysis also showed a higher ratio for insoluble/soluble nitrogen. It is suggested that inhibition of germination is caused by reduced synthesis of amylase which is not mediated through gibberelic acid. Treatment of seeds ofPhaseolus mungo with, 1,3,7-T. caused no change in amylase activity,in vivo nitrate reductase activity, ethanol soluble and insoluble nitrogen and protein content.     

A structural study on the mode of action of CHATM Chemical Hybridizing Agent in wheat

Summary This study has compared mature pollen grains while still in the anther, as well as post-pollination responses, from untreated and CHA^TM Chemical Hybridizing Agent-treated wheat plants using light (bright-field, phase-contrast, and fluorescence), scanning, and transmission electron microscopy. The chemical, azetidine-3-carboxylic acid (A3C), was applied at three treatment levels of 0.75, 1.0 and 1.5 kg/ha for the mature pollen investigations. It was found that the major effect of A3C on mature pollen is an alteration of the wall precursor vesicles (wp-vesicles), which form a high proportion of the contents of the mature grass pollen grain. The degree of deformation of the wp-vesicles is dose dependent. There is some evidence that increased aggregations of ribosomes are formed in treated pollen cytoplasm. Pollination studies (all at a treatment level of 1.0 kg/ha) show that, in most cases, the treated pollen does not germinate, and a high percentage of the pollen grains burst (60% burst grains in treated material compared to 28% in controls). In about 20% of the cases from treated plants, a short pollen tube forms, but no tubes were seen to grow far enough to enter the stigma hairs of the pistil. Thus, A3C does not act by preventing pollen formation, but by the prevention of normal pollen tube growth. There appears to be a specific targeting of the wp-vesicles such that, even in cases where the ultra-structure of the vesicles is not altered, the normal course of events leading to the incorporation of their contents into the extending tube wall is arrested. Further studies must be undertaken to determine the significance of the effect of CHA^TM Chemical Hybridizing Agent on wp-vesicle composition.     

A-002 (Varespladib), a phospholipase A2 inhibitor, reduces atherosclerosis in guinea pigs

Background

High blood pressure (BP) is now an important public health problem in non-industrialised countries. The limited evidence suggests ethnic inequalities in BP in adults in some non-industrialised countries. However, it is unclear whether these ethnic inequalities in BP patterns in adults reflect on adolescents. Hence, we assessed ethnic differences in BP, and the association of BP with body mass index (BMI) among adolescents aged 12–17 years in Paramaribo, Suriname.

Methods

Cross-sectional study with anthropometric and blood pressure measurements. A random sample of 855 adolescents (167 Hindustanis, 169 Creoles, 128 Javanese, 91 Maroons and 300 mixed-ethnicities) were studied. Ethnicity was based on self-reported ethnic origin.

Results

Among boys, Maroons had a lower age- and height-adjusted systolic BP than Creoles, and a lower diastolic BP than other ethnic groups. However, after further adjustment for BMI, only diastolic BP in Maroons was significantly lower than in Javanese (67.1 versus 70.9 mmHg). Creole boys had a lower diastolic BP than Hindustani (67.3 versus 70.2 mmHg) and Javanese boys after adjustment for age, height and BMI. Among girls, there were no significant differences in systolic BP between the ethnic groups. Maroon girls, however, had a lower diastolic BP (65.6 mmHg) than Hindustani (69.1 mmHg), Javanese (71.2 mmHg) and Mixed-ethnic (68.3 mmHg) girls, but only after differences in BMI had been adjusted for. Javanese had a higher diastolic BP than Creoles (71.2 versus 66.8 mmHg) and Mixed-ethnicity girls. BMI was positively associated with BP in all the ethnic groups, except for diastolic BP in Maroon girls.

Conclusion

The study findings indicate higher mean BP levels among Javanese and Hindustani adolescents compared with their African descent peers. These findings contrast the relatively low BP reported in Javanese and Hindustani adult populations in Suriname and underscore the need for public health measures early in life to prevent high BP and its sequelae in later life.     

Chlorophyll in desiccated seeds of a euhalophyte, Suaeda physophora, and its significancy in plant adaptation to salinity during germination

The seed cotyledons of a euhalophyte, Suaeda physophora, were found to be dark green. The pigment extracted from the cotyledons was proved to be chlorophyll for the absorption spectra curve of extracts the same as that for leaves. Photosynthetic oxygen-exchanging could be detected after the seeds were moistened for 6 h. Microstructure of organelles in cotyledons of ungerminated seeds was detected by transmission electron microscopy. Histochemical pigmentation was used to investigate the degree of damage on the membrane of radicles. A xerophyte, Haloxylon persicum, whose cotyledons of desiccated seeds also contain chlorophyll was used as a comparative species. The results showed that S. physophora maintained the ultra-structure of chloroplasts, the integrity of plasma membranes of radicles kept much better than that of H. persicum, which showed the great adaptability to salinity of the euhalophyte even at the seed-germination stage. Seeds were incubated in 0 and 700 mmol/L NaCl for 10 days in darkness at 20 ℃ , then ungerminated seeds in NaCl solution were transferred to deionised water and reincubated for another 8 days and was recorded the germination recovery. Dry seeds moistened with deionised water germinated gradually in the dark and germination was maximal after 3 or 4 d. Seeds at 700 mmol/L NaCl for 10 d and transferred back to deionised water germinated abruptly, most seeds germinated in one day and photosynthesis was also detected. It is concluded that recovery germination of S. physophora ensured the seeds could germinate rapidly after salinity declines, for example under the mild but transitory favorable edaphic condition in early spring. Photosynthesis function in seeds might also promoted radicle growth and seedling establishment.     

Secretory leukocyte protease inhibitor (SLPI) is, like its homologue trappin-2 (pre-elafin), a transglutaminase substrate

Human lungs contain secretory leukocyte protease inhibitor (SLPI), elafin and its biologically active precursor trappin-2 (pre-elafin). These important low-molecular weight inhibitors are involved in controlling the potentially deleterious proteolytic activities of neutrophil serine proteases including elastase, proteinase 3 and cathepsin G. We have shown previously that trappin-2, and to a lesser extent, elafin can be linked covalently to various extracellular matrix proteins by tissue transglutaminases and remain potent protease inhibitors. SLPI is composed of two distinct domains, each of which is about 40% identical to elafin, but it lacks consensus transglutaminase sequence(s), unlike trappin-2 and elafin. We investigated the actions of type 2 tissue transglutaminase and plasma transglutaminase activated factor XIII on SLPI. It was readily covalently bound to fibronectin or elastin by both transglutaminases but did not compete with trappin-2 cross-linking. Cross-linked SLPI still inhibited its target proteases, elastase and cathepsin G. We have also identified the transglutamination sites within SLPI, elafin and trappin-2 by mass spectrometry analysis of tryptic digests of inhibitors cross-linked to mono-dansyl cadaverin or to a fibronectin-derived glutamine-rich peptide. Most of the reactive lysine and glutamine residues in SLPI are located in its first N-terminal elafin-like domain, while in trappin-2, they are located in both the N-terminal cementoin domain and the elafin moiety. We have also demonstrated that the transglutamination substrate status of the cementoin domain of trappin-2 can be transferred from one protein to another, suggesting that it may provide transglutaminase-dependent attachment properties for engineered proteins. We have thus added to the corpus of knowledge on the biology of these potential therapeutic inhibitors of airway proteases.     

A quantitative structure-activity relationship (QSAR) study on glycan array data to determine the specificities of glycan-binding proteins

Advances in glycan array technology have provided opportunities to automatically and systematically characterize the binding specificities of glycan-binding proteins. However, there is still a lack of robust methods for such analyses. In this study, we developed a novel quantitative structure-activity relationship (QSAR) method to analyze glycan array data. We first decomposed glycan chains into mono-, di-, tri- or tetrasaccharide subtrees. The bond information was incorporated into subtrees to help distinguish glycan chain structures. Then, we performed partial least-squares (PLS) regression on glycan array data using the subtrees as features. The application of QSAR to the glycan array data of different glycan-binding proteins demonstrated that PLS regression using subtree features can obtain higher R(2) values and a higher percentage of variance explained in glycan array intensities. Based on the regression coefficients of PLS, we were able to effectively identify subtrees that indicate the binding specificities of a glycan-binding protein. Our approach will facilitate the glycan-binding specificity analysis using the glycan array. A user-friendly web tool of the QSAR method is available at http://bci.clemson.edu/tools/glycan_array.     

Mutagenic properties of a nitrofuran, 7-methoxy-2-nitronaphtho[2, 1-b]furan (R7000), in lacI transgenic mice

The in vivo mutagenic properties of a 5-nitrofuran, the 7-methoxy-2-nitronaphtho[2,1-b]furan (R7000), already well known in bacteria, was evaluated in lacI transgenic mice (Big Blue). The mutation frequency was determined in various organs of i.p. - treated mice and the nature of induced mutations was determined for the target organs in which mutation induction was significant. It was found that R7000 is mutagenic in mice, although, on the basis of the number of induced mutants per unit mass in comparison with other known mutagenic chemicals, R7000 appears to be considerably less mutagenic in mice than in bacteria. The most affected organs, small intestine, caecum and colon organs belong to the digestive apparatus. The distribution of R7000-induced mutations in the lacI gene recovered from small intestine of transgenic mice was very similar to that which had been found in E. coli. The difference between mouse and E. coli in the R7000 induced mutational spectra are mainly in the proportion of single base frameshifts versus base substitutions. Since R7000 induced mutations seemed to arise in the population of stem cells and that the stem cells are important for carcinogenesis, our results are compatible with a possible carcinogenic effect of R7000 and other nitrofurans.     

A potent inhibitor of SIK2, 3, 3', 7-trihydroxy-4'-methoxyflavon (4'-O-methylfisetin), promotes melanogenesis in B16F10 melanoma cells

Flavonoids, which are plant polyphenols, are now widely used in supplements and cosmetics. Here, we report that 4'-methylflavonoids are potent inducers of melanogenesis in B16F10 melanoma cells and in mice. We recently identified salt inducible kinase 2 (SIK2) as an inhibitor of melanogenesis via the suppression of the cAMP-response element binding protein (CREB)-specific coactivator 1 (TORC1). Using an in vitro kinase assay targeting SIK2, we identified fisetin as a candidate inhibitor, possibly being capable of promoting melanogenesis. However, fisetin neither inhibited the CREB-inhibitory activity of SIK2 nor promoted melanogenesis in B16F10 melanoma cells. Conversely, mono-methyl-flavonoids, such as diosmetin (4'-O-metlylluteolin), efficiently inhibited SIK2 and promoted melanogenesis in this cell line. The cAMP-CREB system is impaired in A(y)/a mice and these mice have yellow hair as a result of pheomelanogenesis, while Sik2(+/-); A(y)/a mice also have yellow hair, but activate eumelanogenesis when they are exposed to CREB stimulators. Feeding Sik2(+/-); A(y)/a mice with diets supplemented with fisetin resulted in their hair color changing to brown, and metabolite analysis suggested the presence of mono-methylfisetin in their feces. Thus, we decided to synthesize 4'-O-methylfisetin (4'MF) and found that 4'MF strongly induced melanogenesis in B16F10 melanoma cells, which was accompanied by the nuclear translocation of TORC1, and the 4'-O-methylfisetin-induced melanogenic programs were inhibited by the overexpression of dominant negative TORC1. In conclusion, compounds that modulate SIK2 cascades are helpful to regulate melanogenesis via TORC1 without affecting cAMP levels, and the combined analysis of Sik2(+/-) mice and metabolites from these mice is an effective strategy to identify beneficial compounds to regulate CREB activity in vivo.     

A new species Megabruchidius sophorae (Coleoptera, Bruchidae), feeding on seeds of Styphnolobium (Fabaceae) new to Bruchidae

A new species Megabruchidiussophorae (Insecta, Coleoptera) is described from Japan (Honshu). The larval host of this bruchid is the seeds of the tree legume 'enju', or chinese scholar tree, Styphnolobium japonicum (a senior synonym of Sophora japonica), which is a new host genus to Bruchidae. Styphnolobium is positioned basally in molecular phylogeny of the leguminous subfamily Papilionoideae. Other members of Megabruchidius are known to feed on Gleditsia, the tree legumes that belong to the most ancestral subfamily Caesalpinioideae. Therefore, Megabruchidius utilizes ancestral groups of legumes as its host plants. Megabruchidius has been inferred to be ancestral, based on its behavior. The character state of the host for this third Megabruchidius species supports that the genus is ancestral, at least in the subfamily Bruchinae. We also reviewed the genera closely related to Megabruchidius, i.e., Bruchidius and Sulcobruchus in Bruchidini, and wrote a key to the species in the genus Megabruchidius.     

A quantitative structure-activity relationship study of novel, potent, orally active, selective VEGFR-2 and PDGFRalpha tyrosine kinase inhibitors: derivatives of N-phenyl-N'-{4-(4-quinolyloxy)phenyl}urea as antitumor agents

The tyrosine kinase inhibitory action of the derivatives of N-Phenyl-N'-{4-(4-quinolyloxy)phenyl}urea is quantitatively analyzed using multiple regression analysis. The analysis has helped to ascertain the role of different substituents in explaining the observed inhibitory actions of these compounds for two receptors, namely vascular endothelial growth factor receptor 2 (VEGFR-2) and platelet-derived growth factor receptor alpha (PDGFRalpha). From a derived significant correlation equation for inhibition of VEGFR-2, it was concluded that a less hydrophobic molecule with ortho-substituent(s), exerting less steric hindrance and para-substituent devoid of hydrogen-bond acceptor property augment the inhibition action. Besides, a 3-substituent transmitting a higher negative field effect is advantageous to improve the pIC(50) value of a compound. The correlation equation, derived for the inhibition of PDGFRalpha, has revealed that a less hydrophobic molecule, having a 3-substituent which transmits a more negative resonance effect, is helpful in raising its activity. Likewise, in the middle phenyl ring, absence of a fluoro substituent augments the inhibitory activity. Based on derived QSAR equations pertaining to VEGF-2 and PDGFalpha receptors, the drawn guidelines for selection of substituents, may be used to synthesize potent compounds in future.     

A role for chromogranin A (4-16), a vasostatin-derived peptide, on human colonic motility. An in vitro study

The hypothesis that CgA-derived peptides may be involved in mechanisms modulating motility was tested. Human colonic smooth muscles were studied using an organ bath technique. Acetic acid (AA) effects were characterized on spontaneous mechanical activities (SMA) and on responses to transmural nerve stimulation (NS). AA induced a significant decrease in tone and abolished SMA; this effect was insensitive to either TTX or L-NAME/apamin. The AA-induced inhibitory effects were significantly reduced in the presence of CgA4-16. This effect was insensitive to TTX or L-NAME/apamin. Furthermore, AA-induced effects were blocked in the presence of BAYK8644 and CgA4-16 together. The inhibitory effect of nifedipine was delayed in the presence of CgA4-16. NS induced a triphasic response. Only the excitatory components were reduced in the presence of AA. This effect was dose-related and remained unchanged in the presence of CgA4-16 alone, but was blocked in the presence of simultaneous administration of CgA4-16 and L-NAME/apamin. AA application induced inhibition of human colon motility in vitro. This effect may be mediated through an action on L-type calcium channels. CgA4-16 may display a protective role, which prevents the inhibition of motility due to AA to occur, by acting on both smooth muscle and afferent terminals.     

Development of a colorimetric assay for determining the amount of H2O2 generated in tobacco cells in response to elicitors and its application to study of the structure-activity relationship of flagellin-derived peptides

Plants exhibit various defense responses after recognizing elicitor molecules derived from pathogenic microorganisms and host plants. In this study, we developed an improved colorimetric assay for quantifying the generation of H2O2 in plant cells, one of the defense responses, to evaluate elicitor activity quantitatively. H2O2 is detected using a dye, N-(carboxymethylaminocarbonyl)-4,4'-bis(dimethylamino)-diphenylamine sodium salt (DA-64), which can be measured by conventional spectrometers in a highly sensitive and quantitative manner. Using this method, we successfully measured the elicitor activity of flagellin-derived peptides in cultured tobacco cells, and identified several structural features of the peptides important for the elicitor activity. The results suggest that the structural factors required for expression of the elicitor activity differ slightly among plant species. The efficient and sensitive assay developed in this study should be useful not only for studying structure-activity relationships, but also for the screening of novel compounds that can induce defense responses.     

High pO2-activated inhibitor of protein synthesis in rabbit reticulocytes: its relationship to glutathione disulfide-induced inhibitor and to a approximately 23,000-Mr sulfhydryl protein

Fibronectin is a large dimeric glycoprotein found in plasma, on cell surfaces and as a component of the extracellular matrix which has been implicated in a variety of adhesive processes. The role of fibronectin in platelet function has not been clarified. The present investigation demonstrates that an excess of exogenously added fibronectin inhibits platelet aggregation induced by either thrombin or A23187 at a step subsequent to platelet activation and secretion. Similar concentrations of fibrinogen or von Willebrand factor, both of which also bind to the surface of activated platelets, are not inhibitory. These results are consistent with the concept that fibronectin is one of the important mediators of platelet aggregation.