Stereochemical diversity in lignan biosynthesis of Arctium lappa L

The stereochemistry of lignan biosynthesis in Arctium lappa L. is regulated organ-specifically. (+)-Secoisolariciresinol [81% enantiomeric excess (e.e.)] was isolated from A. lappa petioles. In sharp contrast, lignans whose predominant enantiomers have the opposite absolute configuration to that of (+)-secoisolariciresinol [i.e., (-)-matairesinol (>99% e.e.), (-)-arctigenin (>99% e.e.), and (-)-secoisolariciresinol (65% e.e.)] were isolated from seeds of the species. The stereochemical diversity of secoisolariciresinol was demonstrated with enzyme preparations from A. lappa petioles and seeds. Thus, a petiole enzyme preparation catalyzed the formation of (+)-pinoresinol (33% e.e.), (+)-lariciresinol (30% e.e.), and (+)-secoisolariciresinol (20% e.e.) from achiral coniferyl alcohol in the presence of NADPH and H202, whereas that from ripening seeds catalyzed the formation of (-)-pinoresinol (22% e.e.), (-)-lariciresinol (>99% e.e.), and (-)-secoisolariciresinol (38% e.e.) under the same conditions. In addition, the ripening seed enzyme preparation mediated the selective formation of the optically pure (>99% e.e.) (-)-enantiomer of matairesinol from racemic (+/-)-secoisolariciresinols in the presence of NADP. These results indicate that the stereochemical mechanism for lignan biosynthesis in A. lappa varies with organs, suggesting that multiple lignan-synthesizing isozymes are involved in the stereochemical control of lignan formation in A. lappa.     

Preparative Biorganic Chemistry Part 10 Asymmetric Reduction of Bicyclo[2.2.2]Octane-2,6-Diones with Baker's Yeast

Reduction of bicyclo[2.2.2]octane-2,6-dione with baker's yeast gave (lR,4S,6S)-6-hydroxybi-cyclo[2.2.2]octan-2-one (95% e.e.) contaminated with 8% of its (1S,4R,6S)-isomer. Similarly, the yeast reduction of 1-methylbicyclo[2.2.2]octane-2,6-dione furnished (1R,4S,6S)-6-hydroxy-1-methylbi-cyclo[2.2.2.]octan-2-one (99.5% e.e.) in 59% yield. The yeast reduction of 4-methylbi-cyclo[2.2.2.]octane-2,6-dione afforded (1R,4S,6S)-6-hydroxy-4-methylbicyclo[2.2.2.]octan-2-one (98% e.e.) contaminated with 3% of its (1S,4R,6S)-isomer in 58% yield.     

Synthesis of Dihydrohelminthosporic Acids and their Plant Growth-promoting Activity

In the reduction of (?)-isomenthone with sodium in aqueous ammonia, it was found that the reduction product gives a mixture consisting of 75.5% of (?)-isomenthol (a,e,e), 9.5% of (+)-menthol (e,e,e) and 8.6% of (?)-neoisomenthol (a,a,e). From this fact, it might be concluded that this reduction is stereospecific for isomenthone and is mechanistically different from reduction with sodium and alcohol.     

Microbial production of optically active beta-phenylalanine through stereoselective degradation of racemic beta-phenylalanine

The ability to produce (R)- or (S)-beta-phenylalanine from racemic beta-phenylalanine through stereoselective degradation was screened for. Variovorax sp. JH2 and Arthrobacter sp. the faculty of Agriculture, Kyoto University (AKU) 638 were found to be potential catalysts for (R)- and (S)-beta-phenylalanine production respectively. On 192 h cultivation of Variovorax sp. in medium containing 1.0% (w/v) racemic beta-phenylalanine, 0.46% (w/v) (R)-beta-phenylalanine with an enantiomeric purity of 99% e.e. was obtained. The initial step of the (S)-isomer degradation was stereoselective transamination. On 312 h cultivation of Arthrobacter sp. in medium containing 1.0% (w/v) racemic beta-phenylalanine, 0.51% (w/v) (R)-beta-phenylalanine with an enantiomeric purity of 90% e.e. was obtained. The initial step of the (R)-isomer degradation was supposed to be oxidative deamination. Resting cell reaction with vigorous shaking, with cells of Arthrobacter sp. as the catalyst, resulted in production of 0.49% (w/v) of (S)-beta-phenylalanine with an enantiomeric purity of 99% e.e. from 1.0% (w/v) racemic beta-phenylalanine in 45 h.     

Effects of Different Levels of Intraocular Stray Light on Kinetic Perimetry Findings

PurposeTo evaluate the effect of different levels of intraocular stray light on kinetic perimetry findings.MethodsTwenty-five eyes of 25 healthy young participants were examined by automated kinetic perimetry (Octopus 900) using Goldmann stimuli III4e, I4e, I3e, I2e, and I1e. Each stimulus was presented with a velocity of 3°/s at 24 meridians with 15° intervals. Four levels of intraocular stray light were induced using non-white opacity filter (WOF) filters and WOFs applied to the clear plastic eye covers of the participants. The visual acuity, pupil diameter, isopter area, and kinetic sensitivity of each meridian were analyzed for each WOF density.ResultsVisual acuity deteriorated with increasing WOF densities (p < 0.01). With a visual acuity of 0.1 LogMAR units, the isopter areas for III4e, I4e, I3e, I2e, and I1e decreased by -32.7 degree² (-0.2%), -255.7 degree² (-2.6%), -381.2 degree² (-6.2%), -314.8 degree² (-12.8%), and -59.2 degree² (-15.2%), respectively; kinetic sensitivity for those stimuli decreased by -0.1 degree (-0.1%), -0.8 degree (-1.4%), -1.6 degree (-3.7%), -2.7 degree (-9.7%), and -1.7 degree (-16.2%), respectively. The pupil diameter with each WOF density was not significantly different.ConclusionKinetic perimetry measurements with a high-intensity stimulus (i.e., III4e) were unaffected by intraocular stray light. In contrast, measurements with the I4e, I3e, I2e, and I1e stimuli, especially I2e and I1e, were affected. Changes in the shape of the isopter resulting from opacity must be monitored, especially in cases of smaller and lower-intensity stimuli.     

Preparation of (<Emphasis Type="Italic">R</Emphasis>)-(−)-mandelic acid and its derivatives from racemates by enantioselective degradation with a newly isolated bacterial strain <Emphasis Type="Italic">Alcaligenes</Emphasis> sp. ECU0401

An enantioselective mandelate-degrading bacterium, Alcaligenes sp. ECU0401, was newly isolated from soil. By fed-batch culture, (R)-(-)-mandelic acid was successfully prepared in a 5-L fermenter with 32.8% isolated yield and >99.9% enantiomeric excesses (e.e.) from totally 3.04% (w/v) of racemic mandelic acid after 99 h of biotransformation. The optimal reaction pH and temperature were 6.5 and 30 degrees C, respectively. Using the resting cell as a biocatalyst for asymmetric degradation of racemic mandelic acid and chloro-substituted derivatives thereof, (R)-(-)-mandelic acid, (R)-(-)-o-chloromandelic acid, (S)-(+)-m-chloromandelic acid and (S)-(+)-p-chloromandelic acid were recovered with high analytic yields and excellent enantiomeric excesses (e.e. > 99.9%). (R)-(-)-Mandelic acid could also be obtained after 12 h of biotransformation with 41.5% isolated yield and >99.9% e.e.     

Biochemical approaches to the synthesis of ethyl 5-(s)-hydroxyhexanoate and 5-(s)-hydroxyhexanenitrile

Three different biochemical approaches were used for the synthesis of ethyl 5-(S)-hydroxyhexanoate 1 and 5-(S)-hydroxyhexanenitrile 2. In the first approach, ethyl 5-oxo-hexanoate 3 and 5-oxo-hexanenitrile 4 were reduced by Pichia methanolica (SC 16116) to the corresponding (S)-alcohols, ethyl (S)-5-hydroxyhexanoate 1 and 5-(S)-hydroxyhexanenitrile 2, with an 80-90% yield and >95% enantiomeric excess (e.e). In the second approach, racemic 5-hydroxyhexanenitrile 5 was resolved by enzymatic succinylation, leading to the formation of (R)-5-hydroxyhexanenitrile hemisuccinate and leaving the desired alcohol 5-(S)-hydroxyhexanenitrile 2 with a yield of 34% (50% maximum yield) and >99% e.e. In the third approach, enzymatic hydrolysis of racemic 5-acetoxy hexanenitrile 6 resulted in the hydrolysis of the R-isomer to provide 5-(R)-hydroxyhexanenitrile, leaving 5-(S)-acetoxyhexanenitrile 7 with a 42% yield (50% maximum yield) and >99% e.e.     

Ventilatory and cardiac responses to hypoxia at submaximal exercise are independent of altitude and exercise intensity

The hypoxic exercise test combining a 4,800-m simulated altitude and a cycloergometer exercise at 30% of normoxic maximal aerobic power (MAP) is used to evaluate the individual chemosensitivity to hypoxia in submaximal exercise conditions. This test allows the calculation of three main parameters: the decrease in arterial oxygen saturation induced by hypoxia at exercise (ΔSa(e)) and the ventilatory (HVR(e)) and cardiac (HCR(e)) responses to hypoxia at exercise. The aim of this study was to determine the influence of altitude and exercise intensity on the values of ΔSa(e), HVR(e), and HCR(e). Nine subjects performed hypoxic tests at three simulated altitudes (3,000 m, 4,000 m, and 4,800 m) and three exercise intensities (20%, 30%, and 40% MAP). ΔSa(e) increased with altitude and was higher for 40% MAP than for 20% or 30% (P < 0.05). For a constant heart rate, the loss in power output induced by hypoxia, relative to ΔSa(e), was independent of altitude (4,000-4,800 m) and of exercise intensity. HVR(e) and HCR(e) were independent of altitude (3,000-4,800 m) and exercise intensity (20%-40% MAP). Moreover, the intraindividual variability of responses to hypoxia was lower during moderate exercise than at rest (P < 0.05 to P < 0.001). Therefore, we suggest that HVR(e) and HCR(e) are invariant parameters that can be considered as intrinsic physiological characteristics of chemosensitivity to hypoxia.     

Lipase-catalyzed enantiotope selective acetylation of 2-acyloxypropane-1,3-diols. Influence of the acyl moiety on the selectivity

Preparation and lipase-catalyzed enantiotope selective acetylation of the prochiral 2-acyloxypropane-1,3-diols (1a–h) including sulfonic ester (1a–c) and carboxylic ester (1d–h) series is described. A strong influence of the acyl moiety in these diols on the enantiotope selectivity of the porcine pancreatic lipase (PPL)-catalyzed reaction with vinyl acetate was observed. The best results were achieved with the 2-(4-methylbenzoyl)oxy- and cyclohexanecarbonyloxypropane-1,3-diols (1g and 1h) resulting in acetylated products (2g) of ≥98% e.e. in 77% yield and (2h) of 95% e.e. in 66% yield, respectively.     

Cardiovascular Disease Rates,Outcomes, and Quality of Care in Ontario Métis: A Population-Based Cohort Study

Background

The burden of cardiovascular disease in the Métis, Canada’s fastest growing Aboriginal group, is not well studied. We determined rates of five cardiovascular diseases and associated outcomes in Ontario Métis, compared to the general Ontario population.

Methods

Métis persons were identified using the Métis Nation of Ontario Citizenship Registry. Métis citizens aged 20–105 were linked to Ontario health databases for the period of April 2006 to March 2011. Age- and sex-standardized prevalence and incidence of acute coronary syndromes (ACS), congestive heart failure (CHF), cerebrovascular disease (stroke), atrial fibrillation, and hypertension were compared between the Métis and the general population. Secondary outcome measures included one-year hospitalizations and mortality following the incident cardiovascular diagnosis, as well as quality-of-care measures.

Results

There were 12,550 eligible Métis persons and 10,144,002 in the general population. The adjusted prevalence of each disease was higher (p<0.05) among the Métis compared to the general population: ACS 5.3% vs. 3.0%; CHF 5.1% vs. 3.9%; stroke 1.4% vs. 1.1%; atrial fibrillation 2.1% vs. 1.4%; hypertension 34.9% vs. 29.8%. Incident ACS, stroke, and atrial fibrillation were also higher (p<0.05) among the Métis: ACS 2.4% vs. 1.5%; stroke 0.8% vs. 0.6%; atrial fibrillation 0.6% vs. 0.3%. One-year all-cause and cardiovascular-related mortality were not significantly different. Hospitalizations were higher for Métis persons with CHF (OR 1.93; 95% CI 1.34–2.78) and hypertension (OR 2.27; 95% CI 1.88–2.74). Métis with CHF made more emergency department (ED) visits in the year after diagnosis compared to non-Métis with CHF, while Métis aged ≥65 with ACS were more likely to be on beta-blockers following diagnosis.

Conclusions

The burden of cardiovascular disease was markedly higher in the Métis compared to the general population: prevalence rates for five cardiovascular conditions were 25% to 77% higher. Métis persons with CHF had more frequent hospitalizations and ED visits following their diagnosis.     

A genomic search approach to identify carbonyl reductases in Gluconobacter oxydans for enantioselective reduction of ketones

The versatile carbonyl reductases from Gluconobacter oxydans in the enantioselective reduction of ketones to the corresponding alcohols were exploited by genome search approach. All purified enzymes showed activities toward the tested ketoesters with different activities. In the reduction of 4-phenyl-2-butanone with in situ NAD(P)H regeneration system, (S)-alcohol was obtained with an e.e. of up to 100% catalyzed by Gox0644. Under the same experimental condition, all enzymes catalyzed ethyl 4-chloroacetoacetate to give chiral products with an excellent e.e. of up to 99%, except Gox0644. Gox2036 had a strict requirement for NADH as the cofactor and showed excellent enantiospecificity in the synthesis of ethyl (R)-4-chloro-3-hydroxybutanoate. For the reduction of ethyl 2-oxo-4-phenylbutyrate, excellent e.e. (>99%) and high conversion (93.1%) were obtained by Gox0525, whereas the other enzymes showed relatively lower e.e. and conversions. Among them, Gox2036 and Gox0525 showed potentials in the synthesis of chiral alcohols as useful biocatalysts.     

Kinetic resolution of alpha-acetoxy carboxylic acids with homochiral SuperQuats

Preliminary investigations focused on the kinetic resolution of (+/-)-alpha-acetoxy mandelic carboxylic acid chloride with isopropyl SuperQuat and isopropyl Evans' homochiral auxiliaries. The addition of 2 equiv. of the acid chloride to the lithium salts of the auxiliaries (SuperQuat and Evans') at -100 degrees C in the THF afforded the corresponding N-acyl auxiliaries in high chemical yields (95% and 89%) and d.e.'s of 66% and 40%, respectively. Using the same mandelic acid chloride but incorporating SuperQuat auxiliaries derived from (S)-phenylglycine and (S)-phenylalanine yielded the corresponding N-acyl SuperQuats in 86% and 90% and d.e. 's of 66% and 30%, respectively. Substituting the phenyl group within the alpha-acetoxy mandelic acid chloride for a n-butyl, tert-butyl and cyclohexyl group changed the d.e. significantly when kinetically resolved with isopropyl SuperQuat. The yields were all similar, i.e., approximately 90% but the d.e.'s varied considerably, with values of 20%, 50%, and 82%, respectively. Attempted kinetic resolution of alpha-methoxyphenylacetyl chloride using the lithium salt of isopropyl SuperQuat revealed a diasteroselectivity of 45%, significantly lower than that obtained with the corresponding alpha-acetoxy carboxylic acid chlorides.     

Association of apolipoprotein E phenotypes with late onset Alzheimer's disease: population based study.

OBJECTIVE--To determine the association between the e4 allele of apolipoprotein E and Alzheimer''s disease in a randomly selected population sample. DESIGN--Cross sectional population based study. SUBJECTS--980 people aged 69 to 78 (349 men, 631 women). SETTING--Population of Kuopio, eastern Finland. MAIN OUTCOME MEASURES--Presence of e4 allele and diagnosis of Alzheimer''s disease by detailed neurological and neurophysiological evaluation. RESULTS--46 (4.7%) subjects were classified as having probable or possible Alzheimer''s disease. The frequency of the apolipoprotein E e4 allele was 0.359 in patients with Alzheimer''s disease and 0.165 subjects without dementia (P < 0.0001). The prevalence of Alzheimer''s disease was 2.9% in subjects with no e4 alleles, 7.6% in subjects with one e4 allele, and 21.4% in subjects with two e4 alleles of apolipoprotein E. CONCLUSIONS--Allele e4 of apolipoprotein is associated with Alzheimer''s disease in a dose-response fashion in a randomly selected elderly population.     

Ecological impact on development of hemipterous bug (dysdercus koenigii) (hemiptera: pyrrhocoridae) and boll rot disease of cotton (gossypium hirsutum) grown in the diversified field

The experiment was conducted at Cotton Research Station, Multan to study the impact of weather factors and Hemipterous bug on development of cotton boll disease in cotton variety bt- 886 for three consecutive years i.e., 2012, 2013 and 2014. The results revealed that the population of Red Cotton Bug (RCB) per plant remain 0.50 and 0.34 during years 2012 and 2013, respectively but increased during 2014 i.e., 3.21 per plant. The number of unopened bolls (UOB) were more during 2012 i.e., 13.43% with yellowish lint (YL) 76.30% and whitish lint (WL) 23.70% at average maximum temperature of 34.73◦C, minimum temperature of 22.83◦C, RH of 77.43% and 11.08 mm rainfall. Similarly during 2013, the number of unopened bolls were less i.e., 0.34 per plant with YL 1.48 and WL 99.53 per plant when average maximum temperature 34.60^◦C, minimum temperature 23.37^◦C, RH 73.01% and 9.95 mm rainfall. During 2014, RCB population per plant was 3.22 with no UOB and YL was 0.00% and WL was 100% when average maximum temperature 23.70^◦C, minimum temperature 23.18◦C, RH 71.67% and 4.55 mm rainfall. So our results concluded that the cotton bolls rot disease was more during 2012 due to abrupt changes in environmental factors. The RCB may be the carrier of boll rot disease pathogen during more rainfall.     

Does the geographical gradient of ApoE4 allele exist in China? A systemic comparison among multiple Chinese populations

The allelic frequencies of apolipoprotein E (apoE) vary substantially around the world. There is a conspicuous south-to-north gradient of e4 frequencies in Europe, with the proportion of e4 carriers from only 10–15% in the south to 40–50% in the north. The mechanism may be related to the possibility that e4 carriers are less likely to develop vitamin D deficiency. In addition, Asian populations traditionally have lower e4 frequency than Europeans, which may be attributed in part to the scarce or irregular food supplies in Western world in the recent past. However, whether these geographical distribution gradients exist in China is yet unknown. ApoE genotypes of 200 children from Nanning City were determined by PCR-restriction fragment length polymorphism (RFLP) analysis. Allele frequency data of 18 other populations were collected from published sources and correlated with latitude and longitude information from different geographic resources. In our subjects, the frequencies of apoE genotypes were E3/E3: 73.0%, E3/E2: 15.0%, E4/E3: 5.0%, E4/E4: 5.0%, and E4/E2: 2.0%; the frequencies of apoE alleles were e2: 8.5%, e3: 83.0%, and e4: 8.5%, respectively. The total sample consisted of 3,679 individuals from 19 Chinese populations; the allelic frequencies were e2: 7.6%, e3: 85.5%, and e4: 6.9%, respectively; the proportion of e4 carriers was from 4.9% in Kunming to 17.5% in Harbin. Systemic comparison among multiple Chinese populations revealed that positive correlation existed between the e4 allele frequency distribution and latitude north (r = 0.586, P = 0.008), but no correlation of the e4 allele frequency distribution with longitude east was found (r = −0.018, P = 0.942). We conclude that there is a south-to-north, but not an east-to-west gradient for the apoE4 allele in China.     

Application of polymerase chain reaction for determination of toxins in Escherichia coli strains isolated from pigs with diarrhea.

The PCR method was used for the determination of LTI, STI, STII enterotoxins and Stx2e toxin genes in E. coli strains isolated from pigs with diarrhea. It was shown that most of the strains (77.3%) were enterotoxigenic, producing mainly LTI and STII (30.8%) or STI and STII (21.3%) toxins. It was found that 10.6% of isolates possessed the stx2e genes responsible for the elaboration of shiga toxin 2e.     

Enantioselectivitiy of the nitrile hydratase from Rhodococcus equi A4 towards substituted (R,S)-2-arylpropionitriles

Rhodococcus equi A4 cells containing a nitrile hydratase and an amidase converted (R,S)-2-(4-methoxyphenyl)-propionitrile into the corresponding (S)-acid (e.e. 87%) and (R)-nitrile (e.e. > 95%) in 49% yield. The same reaction using (R,S)-2-(4-chlorophenyl)-propionitrile gave the (S)-acid (e.e. > 95%) and (R)-nitrile (e.e. 52%) in 20 and 34% yield, respectively.     

Hippocampal slice (K+)e: depth profiles and changes induced by stimulation or anoxia

In an attempt to develop a technique which would allow early assessment of the functional state of explanted brain tissue, (K+)e was measured in the CA1 region of rat hippocampal slices using K+-selective microelectrodes. In slices (450 micron) maintained at the boundary between the incubation medium and 95% O2/5% CO2 atmosphere, (K+)e was highest (up to 25-30 mmol/l) immediately below the exposed surface and gradually decreased with depth to (K+) of the bathing fluid (5 mmol/l). (K+)e below the exposed surface remained high throughout the 2 h of incubation. In submersed slices, (K+)e was the highest in the center of the slice (200 micron, 10 mmol/l) and decreased towards both surfaces. During 2 h incubation, (K+)e decreased in the center of the slice to 6 mmol/l in viable preparations remaining high in the deteriorating ones. Electrical stimulation of Schaffer's collaterals (15 V; 0.2 ms; 10 Hz) increased (K+)e of viable slices 200 micron below the surface by 2-3 mmol/l. Similar but slower (K+)e changes were elicited by brief (3 min) anoxic episodes (perfusion with incubation medium equilibrated with 95% N2/5% CO2). It is concluded that submersed slices have a more uniform (K+)e profile as compared to the exposed ones and that low (K+)e in the early phase of incubation is a good predictor of slice viability.     

产碱杆菌ECU0401催化拆分扁桃酸及其衍生物

从土壤中分离的1株产碱杆菌Alcaligenes sp.ECU0401具有扁桃酸脱氢酶活性,可以以扁桃酸、苯甲酰甲酸或苯甲酸为唯一C源生长,并且具有较高的脱氢酶活力。以外消旋扁桃酸为C源,采用分批补料策略培养（或反应）99h,扁桃酸累计投入量为30.4g/L,（S）-（＋）-扁桃酸被完全降解,（R）-（-）-扁桃酸回收产率为32.8%,对映体过量值（e.e.）〉99.9%。利用静息细胞作为催化剂不对称降解外消旋扁桃酸的氯代衍生物,制备获得光学活性的（R）-（-）-邻氯扁桃酸、（S）-（＋）-间氯扁桃酸和（S）-（＋）-对氯扁桃酸,光学纯度均超过99.9%e.e.。     

Chiral synthesis of alpha-phenylpyridylmethanols with Rhizopus arrhizus

The bioreduction of 2-benzoylpyridine (1a) with Rhizopus arrhizus afforded (S)-(+)-alpha-phenyl-2-pyridylmethanol (2a) in 82% enantiomeric excess (e.e.) while the asymmetric hydrolysis of its racemic acetate resulted in the antipode (R)-(-)-2a with 24% optical purity.