Genetic diversity and geographical structure of the pitcher plant Nepenthes vieillardii in New Caledonia: A chloroplast DNA haplotype analysis

Among the many species that grow in New Caledonia, the pitcher plant Nepenthes vieillardii (Nepenthaceae) has a high degree of morphological variation. In this study, we present the patterns of genetic differentiation of pitcher plant populations based on chloroplast DNA haplotype analysis using the sequences of five spacers. We analyzed 294 samples from 16 populations covering the entire range of the species, using 4660 bp of sequence. Our analysis identified 17 haplotypes, including one that is widely distributed across the islands, as well as regional and private haplotypes. The greatest haplotype diversity was detected on the eastern coast of the largest island and included several private haplotypes, while haplotype diversity was low in the southern plains region. The parsimony network analysis of the 17 haplotypes suggested that the genetic divergence is the result of long-term isolation of individual populations. Results from a spatial analysis of molecular variance and a cluster analysis suggest that the plants once covered the entire serpentine area of New Caledonia and that subsequent regional fragmentation resulted in the isolation of each population and significantly restricted seed flow. This isolation may have been an important factor in the development of the morphological and genetic variation among pitcher plants in New Caledonia.     

Pancreatic α-Amylase Controls Glucose Assimilation by Duodenal Retrieval through N-Glycan-specific Binding,Endocytosis, and Degradation

α-Amylase, a major pancreatic protein and starch hydrolase, is essential for energy acquisition. Mammalian pancreatic α-amylase binds specifically to glycoprotein N-glycans in the brush-border membrane to activate starch digestion, whereas it significantly inhibits glucose uptake by Na⁺/glucose cotransporter 1 (SGLT1) at high concentrations (Asanuma-Date, K., Hirano, Y., Le, N., Sano, K., Kawasaki, N., Hashii, N., Hiruta, Y., Nakayama, K., Umemura, M., Ishikawa, K., Sakagami, H., and Ogawa, H. (2012) Functional regulation of sugar assimilation by N-glycan-specific interaction of pancreatic α-amylase with glycoproteins of duodenal brush border membrane. J. Biol. Chem. 287, 23104–23118). However, how the inhibition is stopped was unknown. Here, we show a new mechanism for the regulation of intestinal glucose absorption. Immunohistochemistry revealed that α-amylase in the duodena of non-fasted, but not fasted, pigs was internalized from the pancreatic fluid and immunostained. We demonstrated that after N-glycan binding, pancreatic α-amylase underwent internalization into lysosomes in a process that was inhibited by α-mannoside. The internalized α-amylase was degraded, showing low enzymatic activity and molecular weight at the basolateral membrane. In a human intestinal Caco-2 cell line, Alexa Fluor 488-labeled pancreatic α-amylase bound to the cytomembrane was transported to lysosomes through the endocytic pathway and then disappeared, suggesting degradation. Our findings indicate that N-glycan recognition by α-amylase protects enterocytes against a sudden increase in glucose concentration and restores glucose uptake by gradual internalization, which homeostatically controls the postprandial blood glucose level. The internalization of α-amylase may also enhance the supply of amino acids required for the high turnover of small intestine epithelial cells. This study provides novel and significant insights into the control of blood sugar during the absorption stage in the intestine.     

Characterization of the Polyamine Biosynthetic Pathways and Salt Stress Response in Brachypodium distachyon

Journal of Plant Growth Regulation - To characterize polyamine (PA) biosynthetic pathways in Brachypodium distachyon, we analyzed the gene-expression patterns and PA contents in various organs....     

WGEF is a novel RhoGEF expressed in intestine, liver, heart, and kidney

Rho family GTPases regulate multiple cellular processes through their downstream effectors, where their activities are stimulated by the guanine nucleotide exchange factors. Here, we report a new member of RhoGEF, WGEF, which has the classical structure of DH-PH domain and a C-terminal SH3 domain. WGEF was shown to activate RhoA, Cdc42, and Rac1 by pulldown assay, and forced expression of WGEF resulted in marked rearrangement of the actin cytoskeleton, which is typically seen by the activation of RhoA, Cdc42, and Rac1. WGEF was highly expressed in intestine and also in liver, heart and kidney, which may suggest the involvement of WGEF in the development and functions of these organs. The expression pattern may also suggest the possible importance of WGEF in the understanding of diseases based on metabolic disorder.     

Statins downregulate ATP-binding-cassette transporter A1 gene expression in macrophages

The ATP-binding-cassette transporter A1 (ABCA1) plays an essential role in cellular cholesterol efflux and helps prevent macrophages from becoming foam cells. The statins are widely used as cholesterol-lowering agents and have other anti-atherogenic actions. We tested the effects of four different statins (fluvastatin, atorvastatin, simvastatin, and lovastatin) on ABCA1 expression in macrophages in vitro. The statins suppressed ABCA1 mRNA expression in RAW246.7 and THP-1 macrophage cell lines and in mouse peritoneal macrophages. The effect was time- and dose-dependent and was abolished by the addition of the post-reductase product, mevalonate. These findings imply that there is a possible modulation of the well-known beneficial effects of the statins on the reverse cholesterol transport pathway.     

Decline of Supportive Attitudes among Husbands toward Female Genital Mutilation and Its Association to Those Practices in Yemen

Objectives

To elucidate the attitudes of women and their husband’s towards female genital mutilation (FGM) and their associations with the continuation of FGM upon their daughters.

Methods

Subjects were 10,345 (in 1997) and 11,252 (in 2003) ever married women aged 15 to 49 years from the Yemen Demographic Health Surveys. Performances of FGM on the most-recently-born daughters were investigated. Attitudes of women and their husbands were assessed by their opinions on the continuation of FGM. The association between the attitudes of women and their husbands and performance of FGM on the most-recently-born daughters were investigated after adjusting for age and education of the women.

Findings

The percentage among the most-recently-born daughters who received FGM of women who had undergone FGM declined from 61.9% in 1997 to 56.5% in 2003 (p<0.001). The percentages of women who had undergone FGM and who supported the continuation of FGM and of husbands who also supported its continuation decreased from 78.2% and 60.1% in 1997 to 70.9% and 49.5% in 2003, respectively (both p<0.001). When the women or the husbands did not agree with FGM, it was less likely to be performed on their daughter than when the women or the husbands agreed in 1997 (odds ratio=0.11, 95% confidence interval 0.07-0.16 and odds ratio=0.07, 95% confidence interval 0.04-0.12, respectively) and in 2003 (odds ratio=0.12, 95% confidence interval 0.09-0.16 and odds ratio=0.11, 95% confidence interval 0.07-0.16, respectively).

Conclusion

Non-supportive attitudes of women and their husbands towards the continuation of FGM have become common and were associated with their decision not to perform FGM upon their daughters.