A gas chromatography/mass spectrometry assay to measure estradiol, catecholestradiols, and methoxyestradiols in plasma

We have developed a gas chromatography/mass spectrometry (GC/MS) assay to measure 17beta-estradiol (E) and its biologically active metabolites 2-hydroxyestradiol (2OHE) and 4-hydroxyestradiol (4OHE), and 2-methoxyestradiol (2MEOE) and 4-methoxyestradiol (4MEOE) in rat plasma. All analytes are well separated and show a linear relationship between concentration (0.25-5 pg/microl) and signal, and coefficients of variation (CVs) are low. Intra-assay CV for the lowest quality control samples (QCs) (0.375 pg/microl) were on average for 17beta-estradiol 20.5%, for 2-hydroxyestradiol 15.6%, for 4-hydroxyestradiol 16.5%, for 2-methoxyestradiol 16.5%, and for 4-methoxyestradiol 11.5%. The inter-assay CVs for the lowest QCs were for 17beta-estradiol 12.1%, for 2-hydroxyestradiol 7.1%, for 4-hydroxyestradiol 15.5%, for 2-methoxyestradiol 16.7%, and for 4-methoxyestradiol 9.7%. The highest sensitivity for this assay was observed for hydroxyestradiols followed by the methoxyestradiols and 17beta-estradiol. In summary, we describe a convenient, sensitive, and specific assay to measure 17beta-estradiol and its biologically active metabolites.     

A new sensitive flow-injection chemiluminescence method for the determination of H(2)-receptor antagonists.

Based on the chemiluminescence (CL) intensity generated from the potassium ferricyanide [K(3)Fe(CN)(6)]-rhodamine 6G system in sodium hydroxide (NaOH) medium, a new sensitive flow-injection chemiluminescence (FI-CL) method has been developed, validated and applied for the determination of three kinds of H(2)-receptor antagonists: cimetidine (CIMT), ranitidine (RANT) hydrochloride and famotidine (FAMT). Under the optimum conditions, the linear range for the determination was 1.0 x 10(-9)-7.0 x 10(-5) g/ml for CIMT, 1.0 x 10(-9)-5.0 x 10(-5) g/mL for RANT hydrochloride and 5.0 x 10(-9)-7.0 x 10(-5) g/mL for FAMT. During 11 repeated measurements of 1.0 x 10(-6) g/mL sample solutions, the relative standard deviations (RSDs) were all <5%. The detection limit was 8.56 x 10(-10) g/mL for CIMT, 8.69 x 10(-10) g/mL for RANT hydrochloride and 2.35 x 10(-9) g/mL for FAMT (S:N = 3). This method has been successfully implemented for the analysis of H(2)-receptor antagonists in pharmaceuticals.     

Use of total dietary fiber across four lemur species (Propithecus verreauxi coquereli,Hapalemur griseus griseus,Varecia variegata,and Eulemur fulvus): Does fiber type affect digestive efficiency?

In vivo digestibility and transit of two experimental diets were compared across four lemur species for which gastrointestinal morphology and preliminary data on physiology differ:Varecia variegata (VV), Eulemur fulvus (EF), Propithecus verreauxi (PV), and Hapalemur griseus (HG). Since free-ranging groups consume varied amounts of slowly fermentable insoluble fiber (IF) and rapidly fermentable soluble fiber (SF), differences in digestibility may be related to variation in the fiber types consumed. To investigate this, two diets were designed to provide 28% of dry matter (DM) as total dietary fiber (TDF). The ratio of IF/SF (g/g) differed across the diets (12.15:1 for the IF diet, and 3.76:1 for the IF/SF diet). The DM digestibility (DMD) of both diets differed across species: DMD was lower for EF and VV (approximately 56-58%), and higher for PV (72%) and HG (76%). The fiber digestibility results were as follows: TDF digestibility was similar for VV and EF (23% and 28%), higher for PV (56%), and highest for HG (66%). IF digestibility was lower for VV and EF (20% and 28%), and higher for PV and HG (53% and 62%). The transit times (TTs) of the two markers Cr and Co were similar (approximately 3.5 hr for VV and EF, 25 hr for PV, and 30 hr for HG). The mean retention times (MRTs) showed the same trend. The results from these captive groups suggest there are large differences in digestive efficiency that are likely related to the varied fiber composition of the free-ranging diet, and the amount of time the digesta are retained in the gut.     

Neutralising antibodies for Mayaro virus in Pantanal, Brazil

The Pantanal hosts diverse wildlife species and therefore is a hotspot for arbovirus studies in South America. A serosurvey for Mayaro virus (MAYV), eastern (EEEV), western (WEEV) and Venezuelan (VEEV) equine encephalitis viruses was conducted with 237 sheep, 87 free-ranging caimans and 748 equids, including 37 collected from a ranch where a neurologic disorder outbreak had been recently reported. Sera were tested for specific viral antibodies using plaque-reduction neutralisation test. From a total of 748 equids, of which 264 were immunised with vaccine composed of EEEV and WEEV and 484 had no history of immunisation, 10 (1.3%) were seropositive for MAYV and two (0.3%) for VEEV using criteria of a ≥ 4-fold antibody titre difference. Among the 484 equids without history of immunisation, 48 (9.9%) were seropositive for EEEV and four (0.8%) for WEEV using the same criteria. Among the sheep, five were sero- positive for equine encephalitis alphaviruses, with one (0.4%) for EEEV, one (0.4%) for WEEV and three (1.3%) for VEEV. Regarding free-ranging caimans, one (1.1%) and three (3.4%), respectively, had low titres for neutralising antibodies to VEEV and undetermined alphaviruses. The neurological disorder outbreak could not be linked to the alphaviruses tested. Our findings represent strong evidence that MAYV and all equine encephalitis alphaviruses circulated in the Pantanal.     

A scale of metal ion binding strengths correlating with ionic charge, Pauling electronegativity, toxicity, and other physiological effects

Equilibrium constants for binding to plant plasma membranes have been reported for several metal ions, based upon adsorption studies and zeta-potential measurements. LogK values for the ions are these: Al(3+), 4.30; La(3+), 3.34; Cu(2+), 2.60; Ca(2+) and Mg(2+), 1.48; Na(+) and K(+), 0 M(-1). These values correlate well with logK values for ion binding to many organic and inorganic ligands. LogK values for metal ion binding to 12 ligands were normalized and averaged to produce a scale for the binding of 49 ions. The scale correlates well with the values presented above (R(2)=0.998) and with ion binding to cell walls and other biomass. The scale is closely related to the charge (Z) and Pauling electronegativity (PE) of 48 ions (all but Hg(2+)); R(2)=0.969 for the equation (Scale values)=-1.68+Z(1.22+0.444PE). Minimum rhizotoxicity of metal ions appears to be determined by binding strengths: log a(PM,M)=1.60-2.41exp[0.238(Scale values)] determines the value of ion activities at the plasma membrane surface (a(PM,M)) that will ensure inhibition of root elongation. Additional toxicity appears to be related to softness, accounting for the great toxicity of Ag(+), for example. These binding-strength values correlate with additional physiological effects and are suitable for the computation of cell-surface electrical potentials.     

New Coleoptera records from New Brunswick, Canada: Dryopidae, Elmidae, Psephenidae, and Ptilodactylidae

We report five new species records for New Brunswick, Canada from the Coleoptera families Dryopidae, Elimidae, Psephenidae, and Ptilodactylidae. Dryops viennensis (Heer) (Dryopidae) and Promoresia elegans (LeConte) (Elmidae) are added to the faunal list for New Brunswick and the Maritime provinces. Two Psephenidae species, Ectopria nervosa (Melsheimer) and Ectopria thoracica (Ziegler) are reported for the first time for New Brunswick, and the latter species is also new for the Maritime provinces. Anchytarsus bicolor (Melsheimer) and the family Ptilodactylidae are newly recorded for New Brunswick and the Maritime provinces. Collection, habitat data, and distribution maps are presented for all of these species.     

The role of factor XIa (FXIa) catalytic domain exosite residues in substrate catalysis and inhibition by the Kunitz protease inhibitor domain of protease nexin 2

To select residues in coagulation factor XIa (FXIa) potentially important for substrate and inhibitor interactions, we examined the crystal structure of the complex between the catalytic domain of FXIa and the Kunitz protease inhibitor (KPI) domain of a physiologically relevant FXIa inhibitor, protease nexin 2 (PN2). Six FXIa catalytic domain residues (Glu(98), Tyr(143), Ile(151), Arg(3704), Lys(192), and Tyr(5901)) were subjected to mutational analysis to investigate the molecular interactions between FXIa and the small synthetic substrate (S-2366), the macromolecular substrate (factor IX (FIX)) and inhibitor PN2KPI. Analysis of all six Ala mutants demonstrated normal K(m) values for S-2366 hydrolysis, indicating normal substrate binding compared with plasma FXIa; however, all except E98A and K192A had impaired values of k(cat) for S-2366 hydrolysis. All six Ala mutants displayed deficient k(cat) values for FIX hydrolysis, and all were inhibited by PN2KPI with normal values of K(i) except for K192A, and Y5901A, which displayed increased values of K(i). The integrity of the S1 binding site residue, Asp(189), utilizing p-aminobenzamidine, was intact for all FXIa mutants. Thus, whereas all six residues are essential for catalysis of the macromolecular substrate (FIX), only four (Tyr(143), Ile(151), Arg(3704), and Tyr(5901)) are important for S-2366 hydrolysis; Glu(98) and Lys(192) are essential for FIX but not S-2366 hydrolysis; and Lys(192) and Tyr(5901) are required for both inhibitor and macromolecular substrate interactions.     

Stereoselective biliary elimination of disopyramide and mono-N-desisopropyldisopyramide in humans.

The results of a previous pharmacokinetic study of disopyramide (DP) enantiomers in humans suggested that DP and/or mono-N-desisopropyldisopyramide (MND) may show stereoselective extrarenal elimination. Thus, the present study investigates the biliary elimination of DP and MND enantiomers in three patients who had undergone cholecystectomy for cholelithiasis. DP and MND enantiomers displayed biliary elimination. In both subjects, this elimination pathway showed the same characteristics: (1) biliary elimination of DP and MND was stereoselective, (2) the stereoselectivity was opposite to that observed for the metabolic and renal elimination pathways, i.e., the elimination of the (-)-(R)-enantiomer was higher than that of the (+)-(S)-enantiomer, and (3) biliary elimination of MND was higher than that of DP, for both enantiomers. Estimates of the relative contribution of the biliary clearance in the total clearance of DP and MND indicated that this elimination pathway was secondary, especially for DP. The biliary clearance (expressed as % of total clearance) was 1.9 to 4.0% for (-)-(R)-DP, 1.2 to 1.7% for (+)-(S)-DP, 7.8 to 22.9% for (-)-(R)-MND, and 5.2 to 10.5% for (+)-(S)-MND.     

Inorganic tripolyphosphate (PPP(i)) as a phosphate donor for human deoxyribonucleoside kinases

Inorganic tripolyphosphate (PPP(i)) and pyrophosphate (PP(i)) were examined as potential phosphate donors for human deoxynucleoside kinase (dCK), deoxyguanosine kinase (dGK), cytosolic thymidine kinase (TK1), mitochondrial TK2, and the deoxynucleoside kinase (dNK) from Drosophila melanogaster. PPP(i) proved to be a good phosphate donor for dGK, as well as for dCK with dCyd, but not dAdo, as acceptor substrate, illustrating also the dependence of donor properties on acceptor. Products of phosphorylation were shown to be 5(')-phosphates. In striking contrast to ATP, the phosphorylation reaction follows strict Michaelis-Menten kinetics, with K(m) values of 74 and 92 microM for dCK and dGK, respectively, and V(max) values 40-50% that for ATP. With the other three enzymes, as well as for dCK with dAdo as acceptor, no, or only low levels (相似文献   

Immobilization of bovine serum albumin as a sensitive biosensor for the detection of trace lead ion in solution by piezoelectric quartz crystal impedance

A biosensor based on bovine serum albumin (BSA) for the detection of lead (Pb(2+)) ion was developed and characterized. BSA was immobilized onto a colloidal Au-modified piezoelectric quartz crystal (PQC) as a biosensor for the detection of Pb(2+) ion by piezoelectric quartz crystal impedance (PQCI). Calibration curves for the quantification of Pb(2+) ion showed excellent linearity throughout the concentration range from 1.0 x 10(-7) to 3.0 x 10(-9)mol/L. The interaction between the Pb(2+) ions and the sensor chip is influenced significantly by the pH of the reaction buffer, and the optimal pH for the experiment was 5.4. Under the optimal conditions, the detection limit of 1.0 x 10(-9)mol/L for Pb(2+) was obtained. Kinetic parameters of the Pb(2+)-BSA interactions were also determined by using this chip. The sensor chip could be regenerated for use by dipping in the ethylenediaminetetraacetic acid (EDTA) solution for approximately 2h, and the chip was used to detect Pb(2+) ion for eight times without obvious signal attenuation.     

Re-evaluation of the allometry of wet thermal conductance for birds

Wet thermal conductance is an important thermoregulatory parameter for birds and mammals. It is generally calculated as C(wet) (ml O2 g(-1) h(-1) degrees C(-1)) = VO2/(T(b)-T(a)), where VO2 is metabolic rate measured in ml O2 g(-1) h(-1), T(b) is body and T(a) is ambient temperature measured in degrees C. Minimum C(wet) is measured at T(a) at or below the lower critical temperature (T(lc)) of the thermoneutral zone, and is strongly influenced by time of day (rest or activity phase) and body mass [J. Aschoff, Comp. Biochem. Physiol. 69A (1981) 611]. Allometric analyses indicate differences in C(wet) for passerine and non-passerine birds, in their rest and active phases (Aschoff, 1981). The allometric slope for non-passerine rest-phase (-0.583) is lower than that for non-passerine active-phase (-0.484), and passerine rest-phase (-0.461) and active-phase (-0.463), although none of these slopes are significantly different. This different-sloped relationship for non-passerine rest-phase C(wet) extrapolates to lower-than-expected values at high body mass, and so this allometric relationship may be inappropriate for predictive purposes. Consequently, we have reanalysed Aschoff's (1981) data, as well as more recent compilations, to determine a more useful allometric relationship for C(wet) of non-passerine rest-phase birds. Re-analyses of minimum thermal conductance data from Drent and Stonehouse [Comp. Biochem. Physiol. 40A (1971) 689], Aschoff (1981) and Gavrilov and Dolnik [Acta XVIII Congressus Internationalis Ornithologici Moscow (1982) 421] indicate that the most appropriate regressions for predicting C(wet) (ml O2 g(-1) h(-1) degrees C(-1)) of birds from body mass (M; g) are the pooled regressions for non-passerine and passerine birds, in the active (alpha) and resting (rho) phases, using data tabulated by Aschoff (1981): alpha, C(wet)=0.994M(-0.509); rho, C(wet)=0.702M(-0.519). C(wet) is approximately 40% higher in the active phase than the rest phase. Regressions of various data sets for C(wet) of birds and mammals indicate a similar slope of approximately -0.5 for the allometric relationship, but significantly higher elevations for mammals compared to birds. The approximately 50% higher C(wet) for mammals than birds indicates a better physical insulation for birds than mammals of the same body mass. The general scaling of C(wet) with M(-0.5) indicates that (T(b)-T(lc)) should scale with M(0.22), if mass-specific metabolic rate scales with M(-0.28) [Reynolds and Lee, Am. Nat. 147 (1996) 735]. The observed scaling for (T(b)-T(lc)) of M(0.183) (calculated from Gavrilov and Dolnik, 1985) is consistent with this expectation.     

Evaluation of bluetongue virus (BTV) decontamination techniques for caprine embryos produced in vivo

The objective of this study was to investigate methods of decontaminating early goat embryos that had been infected in vitro with bluetongue virus (BTV). Embryos were isolated from in vivo-fertilized BTV-free goats. Zona pellucida (ZP)-intact 8 to 16 cell embryos were cocultured for 36 h in an insert over a Vero cell monolayer infected with BTV serotype 8. The embryos were then treated with one of five different washing procedures. The treatment standard (TS) comprised phosphate-buffered saline (PBS) + 0.4% BSA (five times over for 10 s), Hank's +0.25% trypsin (twice for 45 s), and then PBS + 0.4% BSA again (five times for 10 s). The four other washing procedures all included the same first and last washing steps with PBS but without BSA (five times for 10 s) and with PBS + 0.4% BSA (five times for 10 s), respectively. The intermediate step varied for each washing procedure. Treatment 1 (T1): 0.25% trypsin (twice for 45 s). Treatment 2 (T2): 0.25% trypsin (twice for 60 s). Treatment 3 (T3): 0.5% trypsin (twice for 45 s). Treatment 4 (T4): 1% hyaluronidase (once for 5 min). After washing, the embryos were transferred and cocultured with BTV indicator Vero cell monolayers for 6 h, to detect any cytopathic effects (CPE). The effectiveness of the different washing techniques in removing the virus was evaluated by RT-qPCR analysis. The TS, T1, T3, and T4 trypsin or hyaluronidase treatments did not eliminate BTV; Treatment 2 eliminated the virus from in vitro infected goat embryos.     

New Coleoptera records for New Brunswick, Canada: Kateretidae, Nitidulidae, Cerylonidae, Endomychidae, Coccinellidae, and Latridiidae

We report 20 new species records for the Coleoptera fauna in New Brunswick, Canada, five of which are new records for the Maritime provinces, including one species that is new for Canada. One species of Kateretidae, Kateretes pusillus (Thunberg) is newly recorded for New Brunswick and the Maritime provinces. Stelidota octomaculata (Say), Phenolia grossa (Fabricius), andCryptarcha strigatula Parsons of the family Nitidulidae are added to the faunal list of New Brunswick; the latter species is new to the Maritime provinces. Two species of Cerylonidae, Philothermus glabriculus LeConte and Cerylon unicolor (Ziegler), are reported for the first time for New Brunswick. Philothermus glabriculus is new for the Maritime provinces. Two species of Endomychidae, Hadromychus chandleri Bousquet and Leschen and Danae testacea (Ziegler) are newly recorded for New Brunswick. Three species of Coccinelidae, Stethorus punctum punctum (LeConte), Naemia seriata seriata Melsheimer, and Macronaemia episcopalis (Kirby) are added to the provincial list. Macronaemia episcopalis (Kirby) is a species new to the Maritime provinces. Nine species of Latridiidae, Cartodere nodifer (Westwood), Dienerella ruficollis (Marsham), Enicmus aterrimus Motschulsky, Enicmus fictus Fall, Encimus histrio Jay and Tomlin, Lathridius minutus (Linnaeus), Stephostethus productus Rosenhauer, Corticaria elongata (Gyllenhal), and Corticarina longipennis (LeConte) are newly recorded for New Brunswick. Stephostehus productus is newly recorded from Canada. Collection and habitat data are presented for all these species.     

Some relations between different characteristics of selection

Consider the action of selection with fitness w(x) on a quantitative trait x. What selection, among those that produce the same value of selection differential, leads to minimal values of (a) genetic load, (b) variance of the relative fitness, and (c) variance of the trait after selection? We have shown that for (a) and (c) the answer is strict truncation, whereas for (b) the answer is linear selection. The results for (a) and (b) are true for any selection, while the result for (c) is true only for directional selection. Implications of these findings are discussed.     

Absorption of CO2 in algal mass culture systems: a different characterization approach

For the characterization of CO(2) absorption in aerated microalgal culture systems, a different approach based on K(L)a(O(2)) determination and transformation was studied. To confirm the validity of this method, the influence of reactions between CO(2) and compounds (OH(-), H(2)O, and NH(3)) present in the culture medium upon the absorption mechanism was evaluated under different physical and chemical culture conditions. Under these conditions, knowledge of the relative magnitudes of the diffusion and reaction kinetics permitted the evaluation of their relative importance. For the determination of the parameters required for the calculation of the CO(2) absorption constant, empirical correlations for K(L) (0) and a were used that had been previously verified with experimental data for O(2) absorption. Since, for the conditions studied, the absorption rate was shown to be independent of the chemical reactions taking place in the liquid phase, the K(L)a for CO(2) could be directly related to the K(L)a for O(2) by a simple factor that took into account the difference in aqueous diffusivity of the two gases. Thus, using methods developed for determining O(2) absorption in gas-liquid contactors, it is possible to adequately characterize CO(2) absorption for laboratory and pilot scale algal production systems.     

VITRIFICATION OF IN VIVO AND IN VITRO PRODUCED OVINE BLASTOCYSTS

Although cryopreservation of bovine embryo has made great progress in recent years, little achievement was obtained in ovine embryo freezing, especially in vitro produced embryos. However, a simple and efficient method for cryopreservation of sheep embryos will be important for application of ovine embryonic techniques such as in vitro fertilization, transgenic, cloning and etc. In this study ovine blastocysts, produced in vivo or in vitro, were cryopreserved by vitrification in EFS40 (40% ethylene glycol (EG), 18% ficoll and 0.5 M sucrose) or GFS40 (40% glycerol (GL), 18% ficoll and 0.5 Mol sucrose). In Vitro produced, early blastocysts were directly plunged into liquid nitrogen (LN₂) after preparation by one of the following procedures at 25°C: (A) equilibration in EFS40 for 1 min; (B) equilibration in EFS40 for 2 min; (C) equilibration in EFS40 for 30 s following pretreatment in 10% EG for 5 min; (D) equilibration in EFS40 for 30s following pretreatment in EFS20 for 2 min (E) equilibration in GFS30 for 30 s following pretreatment in 10% GL for 5 min. The survival rates observed after thawing and in vitro culture for 12 h were A 78.0% (39/50), B 50.0% (26/52), C 93.3% (70/75), D 92.0% (46/50) and E 68.0% (34/50). Survival rates were not significantly different for treatments C and D (p>0.05), but those for groups C and D were significantly higher than for A, B and E (p<0.05). After 24 h in vitro culture, hatched blastocyst rates were A 28.0% (14/50), B 21.1% (11/52), C 49.3% (37/75), D 48.0% (24/50), E 32.0% (16/50) and control 54.0% (27/50). The hatching rates for groups A, B and E were significantly lower than the control (p<0.05) in which early IVF blastocysts were cultured in fresh SOFaaBSA medium following treatment in PBS containing 0.3% BSA for 30 min, but for groups C and D it was similar to the control (p>0.05). The freezing procedures A, B and C were used to vitrify in vivo produced, early blastocysts recovered from superovulated ewes. The survival rates of frozen-thawed in vivo embryos were A 94.7% (72/76), B 75.0% (45/60) and C 96.4% (54/56) and for group B was significantly lower than for the other two treatment groups (p<0.05). Hatched blastocyst rates were A 46.0% (35/76), B 26.6% (16/60), C 51.8% (29/56) and the control 56.7% (34/60) in which early blastocysts from superovulation were cultured in fresh SOFaaBSA medium following treatment in PBS containing 0.3% BSA for 30 min. The hatching rate for treatment B was significantly lower than for the control (p<0.05) but did not differ between groups A, C and the control (p>0.05). Frozen-thawed embryos vitrified by procedure C were transferred into synchronous recipient ewes. Pregnancy and lambing rates were similar for embryos transferred fresh or frozen/thawed for both in vivo and in vitro produced embryos. These rates did not differ between in vivo and in vitro embryos transferred fresh (p>0.05). However, for frozen-thawed embryos, both rates were significantly lower for in vitro than for in vivo produced embryos (p<0.05).     

Comparative study of QTLs for agronomic traits of riceOriza sativa L.) between salt stress and nonstress environment

Genotype-by-environment interactions (GxE) are commonly observed for quantitative traits. In the present study, a doubled haploid (DH) population and its genetic linkage map were used to comparatively study QTLs in salt stress and nonstress environments. A total of 24 QTLs were detected for five agronomic traits, which were distributed on all the chromosomes except 9 and 11. Under the salt stress, nine (37.5%) QTLs were detected, including one for 1 000-grain weight (GW), two for heading date (HD), one for plant height (PH), two for grains per panicle (GPP), and three for effective tillers (ET), while in the nonstress environment, 17 QTLs (70.8%) were detected, including five for GW, six for HD, three for PH, two for GPP, and one for ET. Two QTLs (8.3%) were consistently detected in both environments. One was identified on chromosome 4 for HD and the other on Chr.6 for GPP. Furthermore, three regions carrying multiple QTLs were identified on chromosomes 1, 4 and 8 respectively. For example, on chromosome 8, three QTLs for HD, GW and PH, respectively were identified between RG885-GA408 in nonstress environment, but not in the stress environment. The comparative study of QTLs detected in extremely different (salt stress and nonstress) environments revealed that there existed several QTLs for important agronomic traits on chromosome 8 which were affected significantly by salt stress.     

Comparative study of QTLs for agronomic traits of rice (Oriza sativa L.) between salt stress and nonstress environment

Genotype-by-environment interactions (GxE) are commonly observed for quantitative traits. In the present study, a doubled haploid (DH) population and its genetic linkage map were used to comparatively study QTLs in salt stress and nonstress environments. A total of 24 QTLs were detected for five agronomic traits, which were distributed on all the chromosomes except 9 and 11. Under the salt stress, nine (37.5%) QTLs were detected, including one for 1 000-grain weight (GW), two for heading date (HD), one for plant height (PH), two for grains per panicle (GPP), and three for effective tillers (ET), while in the nonstress environment, 17 QTLs (70.8%) were detected, including five for GW, six for HD, three for PH, two for GPP, and one for ET. Two QTLs (8.3%) were consistently detected in both environments. One was identified on chromosome 4 for HD and the other on Chr.6 for GPP. Furthermore, three regions carrying multiple QTLs were identified on chromosomes 1, 4 and 8 respectively. For example, on chromosome     

Assigning stereodiversity of the 27-Me group of furostane-type steroidal saponins via NMR chemical shifts

Applicability of (13)C and (1)H NMR chemical shifts for the assignment of the 25R/25S configuration of the 27-methyl group in the case of furostane-type steroidal saponins has been investigated. A comparative study of (13)C NMR data suggest that chemical shift values for C-20, C-21, C-22, C-23, C-24, C-25, C-26 and C-27 resonances were not much influenced by R/S configuration of the 27-Me group, thus reflecting limited application of (13)C NMR chemical shifts for such stereochemical determinations. In contrast, (1)H NMR chemical shifts (delta(a), delta(b)) for geminal protons of glycosyloxy methylene (H(2)-26) exhibit pronounced dependence and the difference (Delta(ab)=delta(a)-delta(b)) among their chemical shifts [Delta(ab)= or <0.48 for 25R; Delta(ab)= or >0.57 for 25S] seems to be of general applicability for ascertaining 25R/25S orientation of the 27-methyl group of furostane-type steroidal saponins.     

Comparative study of QTLs for agronomic traits of riceOriza sativa L.) between salt stress and nonstress environment

Genotype-by-environment interactions (GxE) are commonly observed for quantitative traits. In the present study, a doubled haploid (DH) population and its genetic linkage map were used to comparatively study QTLs in salt stress and nonstress environments. A total of 24 QTLs were detected for five agronomic traits, which were distributed on all the chromosomes except 9 and 11. Under the salt stress, nine (37.5%) QTLs were detected, including one for 1 000-grain weight (GW), two for heading date (HD), one for plant height (PH), two for grains per panicle (GPP), and three for effective tillers (ET), while in the nonstress environment, 17 QTLs (70.8%) were detected, including five for GW, six for HD, three for PH, two for GPP, and one for ET. Two QTLs (8.3%) were consistently detected in both environments. One was identified on chromosome 4 for HD and the other on Chr.6 for GPP. Furthermore, three regions carrying multiple QTLs were identified on chromosomes 1, 4 and 8 respectively. For example, on chromosome 8, three QTLs for HD, GW and PH, respectively were identified between RG885-GA408 in nonstress environment, but not in the stress environment. The comparative study of QTLs detected in extremely different (salt stress and nonstress) environments revealed that there existed several QTLs for important agronomic traits on chromosome 8 which were affected significantly by salt stress.