Major QTLs associated with green stem disorder insensitivity of soybean (Glycine max (L.) Merr.).

Green stem disorder (GSD) is one of the most serious syndromes affecting soybean (Glycine max) cultivation in Japan. In GSD, stems remain green even when pods mature. When soybean plants develop GSD, seed surfaces are soiled by tissue fluid and seed quality is deteriorated during machine harvesting. We performed quantitative trait locus (QTL) analyses for GSD insensitivity using recombinant inbred lines (RILs; n = 154) derived from a cross between an insensitive line ('Touhoku 129') and a sensitive leading cultivar ('Tachinagaha') during a 6-year evaluation. Three effective QTLs were detected. The influences of these QTLs were in the following order: qGSD1 (LG_H) > qGSD2 (LG_F) > qGSD3 (LG_L). At these three QTLs, 'Touhoku 129' genotypes exhibited more GSD insensitivity than 'Tachinagaha' genotypes. The lower incidence of GSD for 'Touhoku129' was attributable primarily to these three QTLs because RILs harboring a 'Touhoku 129' genotype at the three QTLs exhibited a GSD incidence similar to that of 'Touhoku 129.' Although a limitation of this study is that only one mapping population was evaluated, this QTL information and the flanking markers of these QTLs would be effective tools for resolving GSD in soybean breeding programs.

Identification of 33 polymorphisms in the adipocyte-derived leucine aminopeptidase (ALAP) gene and possible association with hypertension.

Adipocyte-derived leucine aminopeptidase (ALAP) inactivates angiotensin II and/or generates bradykinin in the kidney, suggesting a possible role for ALAP in the regulation of blood pressure. We considered the hypothesis that genomic variants of the ALAP gene are associated with hypertension or individual variations in blood pressure. We screened for mutations in the ALAP gene in 48 unrelated Japanese individuals and identified 33 polymorphisms including 15 novel polymorphisms. We then performed a two-stage analysis. In the first stage, the eight missense polymorphisms were evaluated for associations with blood pressure in 96 apparently healthy individuals. In the second stage, only the most promising polymorphisms were evaluated for association with essential hypertension in 143 hypertensive and 348 normotensive subjects. Among the eight missense polymorphisms, the Ile276Met and Lys528Arg polymorphisms showed significant association with blood pressure. Subsequent analysis confirmed association between the Lys528Arg polymorphism and essential hypertension. The estimated odds ratio for essential hypertension was 2.3 for presence of the Arg allele at codon 528, in comparison with presence of the Lys/Lys genotype (P = 0.004). These findings support involvement of ALAP in the regulation of blood pressure.

Effects of hormone replacement therapy and hepatic lipase polymorphism on serum lipid profiles in postmenopausal Japanese women.

The purpose of this study was to evaluate the relationships among hepatic lipase (HL) polymorphism, serum lipids, lipoproteins, and remnant-like particle cholesterol (RLP-C) and to determine the effects of hormone replacement therapy (HRT). We assessed the HL polymorphism in 209 postmenopausal Japanese women. Levels of serum total cholesterol, low density lipoprotein (LDL) cholesterol, high density lipoprotein (HDL) cholesterol, triglycerides, apolipoprotein (Apo) AI, Apo B, Apo E, Apo CII, Apo CIII, and RLP-C were measured before and after 3 months of HRT. The frequency of each genotype was 32% for -514 C/C, 41% for C/T, and 27% for T/T. Subjects with the C/T and T/T genotypes had higher levels of HDL cholesterol and Apo AI than those with the C/C genotype. Those with the T/T genotype had higher levels of RLP-C than those with the C/C or C/T genotype. Serum total cholesterol, LDL cholesterol, Apo B, Apo E, and Apo CII were decreased, and HDL cholesterol and Apo AI were increased significantly in all genotypes after 3 months of HRT. There were no differences in these changes with genotype. The HL polymorphism was associated with higher levels of HDL cholesterol, Apo AI, and RLP-C, and the HL gene variation may contribute to HL activity and affect serum lipoprotein metabolism. Effects of HRT on serum lipids, lipoproteins, and remnant lipoprotein metabolism were unaffected by the HL polymorphism.

Relation of the -514C/T polymorphism in the hepatic lipase gene to serum HDL and LDL cholesterol levels in postmenopausal women under hormone replacement therapy.

Hepatic lipase (HL) is a lipolytic enzyme that catalyzes hydrolysis of triglycerides and phospholipids in all major classes of lipoproteins. Recently, a -514C/T polymorphism in the promoter region of the HL gene was found to be associated with variations in hepatic lipase activity and serum high density lipoprotein cholesterol (HDL-C) levels. Postmenopausal hormone replacement therapy (HRT) has known favorable effects on serum lipid and lipoprotein levels. In this study, we examined the relation between the -514C/T polymorphism and serum lipid and lipoprotein levels in postmenopausal women prior to and after 3 months of HRT. Significant associations between the -514 C/T polymorphism and HDL-C, low density lipoprotein cholesterol (LDL-C) and apolipoprotein A-I (apo A-I) levels were observed before and/or after 3 months of HRT. With HRT, serum total cholesterol (TC), LDL-C and apolipoprotein B (apo B) levels were reduced significantly (P=0.0001), and HDL-C and apo A-I levels were increased significantly (P=0.0001). However, the degrees of change in lipid and lipoprotein levels due to HRT did not differ significantly between the HL genotypes.

Associations between serum high-density lipoprotein cholesterol or apolipoprotein AI levels and common genetic variants of the ABCA1 gene in Japanese school-aged children.

ATP-binding cassette transporter A1 (ABCA1) plays an important role in apolipoprotein AI (apoAI)-mediated cholesterol efflux from peripheral cells. The mild changes in ABCA1 activity due to genomic variation might be associated with interindividual variations in serum high-density lipoprotein cholesterol (HDL-C) and apoAI levels, or primary hypoalphalipoproteinemia in the general population. In the present study, we analyzed the relationships between 5 single nucleotide polymorphisms (SNPs) and 2 insertion/deletion polymorphisms in the 5' flanking region and 5 missense polymorphisms of the ABCA1 gene and serum lipid levels in healthy school-aged children. We detected significant associations between the K219R and V771M polymorphisms, and HDL-C or apoAI levels. The present data support the proposition that the K219 allele is an anti-atherogenic allele with increased cholesterol efflux activity. Similarly, the M771 allele appears to be anti-atherogenic, although the frequency of the M771 allele is low.

Effects of hormone replacement therapy and methylenetetrahydrofolate reductase polymorphism on plasma folate and homocysteine levels in postmenopausal Japanese women.

OBJECTIVE: To evaluate the relationships among the methylenetetrahydrofolate reductase (MTHFR) polymorphism, plasma folate, total homocysteine (Hcy) levels, lipids, and the reduction of Hcy levels resulting from hormone replacement therapy (HRT). DESIGN: Clinical study. SETTING: Outpatient department of obstetrics and gynecology in a general hospital. PATIENT(S): Two hundred seventeen postmenopausal Japanese women. INTERVENTION(S): Of the 217 women, 172 patients were under continuous treatment with oral conjugated equine estrogen and medroxyprogesteron acetate. MAIN OUTCOME MEASURE(S): Fasting Hcy, folate, methionine, lipids, and apolipoproteins were measured before and after 3 months of HRT. RESULT(S): The plasma Hcy concentration was significantly higher in the low folate than in the high-folate group only in patients with the homozygous (T/T) mutant. Plasma Hcy concentrations were significantly correlated with age (R = 0.64, P=.02) or years since menopause (R = 0.73, P=.02) only in the low-folate group with T/T. The plasma Hcy concentration decreased significantly in all genotypes after 3 months of HRT, but the levels of serum folate and methionine remained unchanged. CONCLUSION(S): The MTHFR polymorphism was associated with a higher Hcy concentration, and this association was related to the serum folate level. Hormone replacement therapy reduced the plasma Hcy concentration independently of the MTHFR polymorphism.

Relationship between serum HDL-C levels and common genetic variants of the endothelial lipase gene in Japanese school-aged children.

Endothelial lipase (EL) is a new member of the triglyceride lipase family, the genes of which play a central role in dietary fat absorption, energy homeostasis, and plasma lipoprotein metabolism. One physiologic role of EL is thought to be hydrolysis of high-density lipoprotein (HDL) phospholipid, although the precise function of endothelial lipase has yet to be fully clarified. Furthermore, genetic variation in EL has been suggested to influence serum HDL-C levels. In the present study, we detected two common single nucleotide polymorphisms in the EL gene associated with serum HDL cholesterol levels in healthy school-aged children. Our data support the hypothesis that variations in the EL gene are one of the genetic determinants of serum HDL-C levels.