Asymmetric bioreduction of γ- and δ-keto acids by native carbonyl reductases from Saccharomyces cerevisiae

Optically pure(R)-γ-and(R)-δ-lactones can be prepared by intramolecular cyclization of chiral hydroxy acids/esters reduced asymmetrically from γ-and δ-keto acids/esters using Saccharomyces cerevisiae(S.cerevisiae) as a whole-cell biocatalyst.However,some of the enzymes catalyzing these reactions in S.cerevisiae are still unknown up to date.In this report,two carbonyl reductases,OdCRl and OdCR2,were successfully discovered,and cloned from S.cerevisiae using a genome-mining approach,and overexpressed in Escherichia coli(E.coli).Compared with OdCR1,OdCR2 can reduce 4-oxodecanoic acid and 5-oxodecanoic acid asymmetrically with higher stereoselectivity,generating(R)-γ-decalactone(99% ee) and(R)-δ-decalactone(98% ee) in 85% and 92%yields,respectively.This is the first report of native enzymes from S.cerevisiae for the enzymatic synthesis of chiral γ-and δ-lactones which is of wide uses in food and cosmetic industries.

Pyruvate-Dependent Changes in Neutrophil Amino- and Alpha-Keto Acid Profiles or Immunity: Which Mechanisms Are Involved?

High current findings indicate that a substitution with pyruvate can lead to significant alterations or even improvement in neutrophil immunonutrition. However, it is still unknown which intra-cellular pathways might be involved here. Hence, in this study, we investigated whether preincu-bation with an inhibitor of ·NO-synthase (L-NAME), an ·NO donor (SNAP), an analogue of taurine (beta-alanine), an inhibitor of ornithine-decarboxylase (DFMO) as well as a glutamine-analogue (DON), is able to alter the intragranulocytic metabolic response to pyruvate, here for example studied for neutrophil intracellular amino- and α-keto acid concentrations or important neutrophil immune functions [released myeloperoxidase (MPO), the formation of superoxide anions O2- and hydrogen peroxide (H2O2)]. In summary, the interesting first results presented here showed, that any damage of specific metabolic pathways or mechanisms, which seem directly or indirectly to be involved in relevant pyruvate dependent granulocytic nutrient content or specific cellular tasks, could lead to therapeutically desired, but also to unexpected or even fatal consequences for the affected cells. We therefore continue to believe that pyruvate, irrespective of which exact biochemical mechanisms were involved, in neutrophils may satisfy the substantial metabolic demands for a potent intracellular nutrient.

Effects of keto acid supplements on Chinese patients receiving maintenance hemodialysis:a prospective,randomized,controlled,single-center clinical study

Background:The effects of keto acid(KA)supplements on Chinese patients receiving maintenance hemodialysis(MHD)are unclear.This study aimed to evaluate the effects of KA supplementation on nutritional status,inflammatory markers,and bioelectric impedance analysis(BIA)parameters in a cohort of Chinese patients with MHD without malnutrition.Methods:This was a prospective,randomized,controlled,single-center clinical study conducted in 2011 till 2014.Twenty-nine patients with MHD were randomly assigned to a control(n=14)or a KA(n=15)group.The control group maintained a dietary protein intake of 0.9 g/kg/day.The KA group received additional KA supplement(0.1 g/kg/day).BIA was used to determine the lean tissue mass,adipose tissue mass,and body cell mass.The patients,nutritional status,dialysis adequacy,and biochemical parameters were assessed at the ends of the third and sixth months with t test or Wilcoxon rank-sum test.Results:The daily total energy intake for both groups was about 28 kcal/kg/day.After 6 months,the Kt/V(where K is the dialyzer clearance of urea,t is the dialysis time,and V is the volume of the distribution of urea)was 1.33±0.25 in KA group,and 1.34±0.25 in the control group.The median triceps skin-fold thickness in KA group was 12.00 and 9.00 mm in the control group.In addition,the median hand-grip strength in KA group was 21.10 and 25.65 kg in the control group.There were no significant differences between the groups with respect to the anthropometry parameters,dialysis adequacy,serum calcium and phosphorus levels,inflammatory markers,and amino-acid profiles,or in relation to the parameters determined by BIA.Both groups achieved dialysis adequacy and maintained nutritional status during the study.Conclusions:In this cohort of Chinese patients with MHD,the patients in the control group whose dietary protein intake was 0.9 g/kg/day and total energy intake was 28 kcal/kg/day,maintained well nutritional status during study period.The KA supplement(0.1 g/kg/day)did not improve the essential amino acid/non-essential amino acid ratio,nor did it change the patients5 mineral metabolism,inflammatory parameters,or body compositions.

Decarboxylative Alkylation of β-Keto Acids with Isochromans under Oxidative Conditions

An unprecedented decarboxylative alkylation reaction of fl-keto acids with isochromans has been developed under oxidative conditions. A range of β-keto acids smoothly undergo decarboxylative alkylation with isochromans in the presence of 2,2,6,6-tetramethylpiperdine-1-oxoammonium hexafluorophosphate to give structurally diverse 1-acylmethylisochromans in moderate to excellent yields with extremely high regioselectivity.

Synthesis of the p-keto acids from benzimidazolium iodides and ethyl malonate

The reaction of benzhnidazole methiodide with ethyl malonate in the existence of base was studied,and a new convenient synthetic method of the β-keto acid was provided.

Acetyl-11-keto-β-boswellic acid extracted from Boswellia serrata promotes Schwann cell proliferation and sciatic nerve function recovery

Frankincense can promote blood circulation. Acetyl-11-keto-β-boswellic acid （AKBA） is a small molecule with anti-inflammatory properties that is derived from Boswellia serrata. Here, we hypothesized that it may promote regeneration of injured sciatic nerve. To address this hypothesis, we established a rat model of sciatic nerve injury using a nerve clamping method. Rats were administered AKBA once every 2 days at doses of 1.5, 3, and 6 mg/kg by intraperitoneal injection for 30 days from the 1st day after injury. Sciatic nerve function was evaluated using the sciatic functional index. Degree of muscle atrophy was measured using the triceps surae muscle Cuadros index.Neuropathological changes were observed by hematoxylin-eosin staining. Western blot analysis was used to detect expression of phospho-extracellular signal-regulated kinase 1 and 2 （p-ERK1/2） in injured nerve. S100 immunoreactivity in injured nerve was detected by immunohistochemistry. In vivo experiments showed that 3 and 6 mg/kg AKBA significantly increased sciatic nerve index, Cuadros index of triceps muscle, p-ERK1/2 expression, and S100 immunoreactivity in injured sciatic nerve of sciatic nerve injury model rats. Furthermore,for in vitro experiments, Schwann cells were treated with AKBA at 0–20 μg/mL. Proliferation of Schwann cells was detected by Cell Counting Kit-8 colorimetry assay. The results showed that 2 μg/mL AKBA is the optimal therapeutic concentration. In addition, ERK phosphorylation levels increased following 2 μg/mL AKBA treatment. In the presence of the ERK1/2 inhibitor, PD98059 （2.5 μL/mL）, the AKBA-induced increase in p-ERK1/2 protein expression was partially abrogated. In conclusion, our study shows that AKBA promotes peripheral nerve regeneration with ERK protein phosphorylation playing a key role in this process.

Ferric chloride-catalyzed decarboxylative alkylation of β-keto acids with benzylic alcohols

β-Keto acids are unstable to heat,acids,and bases,and have rarely been employed as carbon nucleophiles for the formation of carbon-carbon bonds.In this context,an efficient decarboxylative alkylation reaction of β-keto acids with benzylic alcohols has been developed,for the first time,through sequential cleavage of carbon-oxygen and carbon-carbon bonds.In the presence of 10 mol% of ferric chloride,a range of β-keto acids smoothly undergo decarboxylative alkylation with benzylic alcohols to give structurally diverse unsymmetric ketones in moderate to excellent yields and with extremely high regioselectivity.Preliminary mechanistic studies indicate that the reaction proceeds through an SN1 alkylation followed by decarboxylation.

硫胺素对体外瘤胃发酵参数及支链脂肪酸合成的影响

本试验旨在通过体外法评估硫胺素对瘤胃发酵参数及支链脂肪酸(BCFA)合成的影响。试验分为6个组,每组5个重复,共发酵2批。各组均以0.5 g全混合日粮(TMR)作为发酵底物,并分别添加0(对照)、15、30、60、120、240 mg/kg DM硫胺素。体外39℃恒温培养24 h后收集发酵液,测定瘤胃发酵参数、脂肪酸含量以及支链α酮酸脱氢酶(BCKD)活性。结果显示:1)30 mg/kg DM硫胺素组发酵液中总挥发性脂肪酸含量显著低于对照组和120、240 mg/kg DM硫胺素组(P<0.05),15、30 mg/kg DM硫胺素组发酵液中总支链挥发性脂肪酸含量显著低于对照组和120、240 mg/kg DM硫胺素组(P<0.05),15、30和60 mg/kg DM硫胺素组发酵液中微生物蛋白含量显著高于对照组和120、240 mg/kg DM硫胺素组(P<0.05)。2)60 mg/kg DM硫胺素组发酵液中饱和脂肪酸含量显著高于对照组和15、120、240 mg/kg DM硫胺素组(P<0.05),120和240 mg/kg DM硫胺素组发酵液中不饱和脂肪酸、单不饱和脂肪酸含量显著高于30和60 mg/kg DM硫胺素组(P<0.05),60 mg/kg DM硫胺素组发酵液中总脂肪酸含量显著高于对照组和15 mg/kg DM硫胺素组(P<0.05)。3)30和60 mg/kg DM硫胺素组发酵液中异构支链脂肪酸(Iso)、反式异构支链脂肪酸(Anteiso)和BCFA含量显著高于对照组(P<0.05)。4)15、30、60、120 mg/kg DM硫胺素组发酵液中BCKD活性显著高于240 mg/kg DM硫胺素组(P<0.05)。5)相关性分析结果显示,发酵液中乙酸(r=-0.59)、丁酸(r=-0.61)、异戊酸(r=-0.54)、总挥发性脂肪酸(r=-0.57)含量与BCFA含量具有中等强度的负相关关系(P<0.05)。综上所述,体外条件下,硫胺素会影响瘤胃发酵特性和脂肪酸的合成,且挥发性脂肪酸含量与BCFA含量存在相关性。当硫胺素添加水平为60 mg/kg DM时,BCFA的合成效果最佳。

低蛋白饮食联合复方α-酮酸对维持性腹膜透析的疗效

目的:探讨低蛋白饮食联合复方α-酮酸对维持性腹膜透析(CAPD)的疗效。方法:88例CAPD患者以随机数字表法分为对照组和观察组各44例。对照组予以低蛋白饮食干预,观察组在以上基础联合复方α-酮酸治疗,观察两组钙磷代谢、营养状况、肾功能、炎症因子及不良反应。结果:治疗后,两组P、Ca×P、iPTH、营养状况指标、肾功能指标、炎症因子水平较治疗前均下降,观察组优于对照组(P<0.05),两组Ca水平治疗前后变化不显著(P>0.05);两组不良反应发生率差异不显著(P>0.05)。结论:低蛋白饮食联合复方α-酮酸对CAPD患者疗效良好。

芳构化法合成2,5-二羟基对苯二甲酸反应机理的密度泛函理论研究

采用密度泛函理论(DFT)计算,研究了由1,4-环己二酮-2,5-二甲酸二甲酯(DMSS)制备2,5-二羟基对苯二甲酸(DHTA)的反应机理.其中,采用IEFPCM溶剂模型着重计算了DMSS由酮式互变异构为烯醇式的溶剂效应,并探究了碘在催化DMSS烯醇式氧化芳构化过程中的作用机制.计算结果表明,在溶剂分子的辅助下,DMSS酮-烯醇式互变异构反应的能垒显著降低;芳构化过程中,碘首先与过氧化氢反应生成活性物质次碘酸,其催化DMSS烯醇式发生碘代反应,并经过后续的消去和互变异构生成2,5-二羟基对苯二甲酸二甲酯(DMDHT),DMDHT进一步水解生成DHTA.同时,通过核磁共振氢谱测试验证了DMSS酮-烯醇式互变异构的溶剂效应;反应性能考评实验结果表明,相较于无催化剂,在碘的催化作用下,DMDHT产品的纯度和收率更高.

白藜芦醇苷对血栓形成及血浆TXB_2和6-keto-PGF_(1α)水平的影响(英文)

研究了白藜芦醇苷(polydatim,PD)的抗血栓形成作用及其作用机制。采用小鼠尾静脉注射花生四烯酸(arachidonicacid,AA)、电刺激大鼠颈动脉血栓形成方法评价PD的抗血栓形成作用;运用放射免疫法测定polydatin对兔血浆血栓素B2(thromboxaneB2,TXB2)及6酮前列腺素F1α(6ketoprostaglandinF1α,6ketoPGF1α)水平的影响。结果显示PD对AA、电刺激大鼠颈动脉引起的血栓形成具有明显的对抗作用;PD亦能降低兔血浆TXB2含量并升高6KetoPGF1α水平。本实验提示PD有明显的抗血栓形成作用,其机制可能与其降低血浆TXB2含量及升高6KetoPGF1α水平密切相关。

提高维生素C二步发酵种子质量的方法

通过在维生素C二步种液培养基中添加半胱氨酸或(和)氯化钙的方法,研究了这2种物质对二步菌种生长和产2-酮基-L-古龙酸(2-KLG)的影响。结果表明,在二步种子培养基中加入适量的半胱氨酸和(或)氯化钙能够促进普通生酮基古龙酸菌生长,提高菌体密度,协调混菌比例,提高种子质量,并提高后续发酵2-酮基-L-古龙酸生成速率,缩短发酵周期。在种子培养基中同时加入0.3 g/L半胱氨酸和0.6 g/L氯化钙培养效果最显著:种液中普通生酮基古龙酸菌浓度提高30.77%,发酵周期缩短8.33%,2-酮基-L-古龙酸生成速率提高9.31%。

低蛋白与酮酸饮食干预对糖尿病肾病小鼠肾脏功能的影响

目的 探讨低蛋白饮食与补充酮酸饮食对糖尿病肾病小鼠肾脏组织结构和功能的影响。方法 18只雄性db/db小鼠(2型糖尿病肾病模型小鼠)采用随机数字表法分为正常蛋白饮食组、低蛋白饮食组、低蛋白-酮酸饮食组,每组各6只。6只db/m小鼠(db/db小鼠的对照)为正常对照组,给予正常蛋白饮食。相应饮食干预12周,每2周测定小鼠体重。喂养结束后,小鼠当天禁食过夜,第2天记录小鼠的24 h饮水量、排尿量,而后取血测定血糖、肌酐、尿素氮、TG、TC,并处死小鼠取肾称重,测量肾脏横径以大体反映肾脏体积,计算肾重/体重比值,HE染色和PAS染色观察肾脏组织系膜细胞增生情况,免疫组化染色测定肾脏组织转化生长因子-β1、Ⅳ型胶原表达水平。结果 与正常对照组比较,正常蛋白饮食组小鼠体重均增加(均P<0.05),24 h饮水量、排尿量均增加(均P<0.05);血糖、血肌酐、尿素氮、TG、TC水平均升高(均P<0.05);肾脏周围组织脂肪增加,体积增大;染色结果显示肾脏组织内系膜细胞增生增加,转化生长因子-β1、Ⅳ型胶原表达水平均增加(均P<0.05)。与正常蛋白饮食组比较,低蛋白饮食组、低蛋白-酮酸饮食组小鼠体重均降低(均P<0.05),24 h饮水量、排尿量均减少(均P<0.05),血糖、血肌酐、尿素氮、TG、TC水平均下降(均P<0.05);肾脏周围组织脂肪减少,体积有所下降;染色结果显示肾脏组织内系膜细胞增生减轻,转化生长因子-β1、Ⅳ型胶原表达水平均降低(均P<0.05)。结论 低蛋白与酮酸饮食干预可改善糖尿病肾病小鼠肾功能生化指标,降低肾脏组织转化生长因子-β1、Ⅳ型胶原表达,从而改善肾脏功能。

乳香提取物调控Wnt/β-catenin信号通路抑制结直肠癌细胞侵袭转移的作用机制研究

目的研究乳香提取物对人结肠癌细胞HCT-116增殖和侵袭转移的影响及可能的作用机制。方法体外培养人结肠癌细胞珠HCT-116,使用不同浓度乳香提取物乙酰基-11-酮基-β-乳香酸(AKBA)分别作用于细胞相同时间后,以CCK-8实验、Transwell细胞侵袭实验、划痕实验检测其对细胞增殖和侵袭转移的影响,以Western blotting、荧光定量PCR等方法探究其对细胞侵袭转移相关蛋白、mRNA表达的影响。结果AKBA可抑制人结肠癌细胞HCT-116的增殖、迁移能力,且呈剂量依赖(P<0.05);AKBA可抑制C-Myc、β-catenin的蛋白和mRNA表达,且呈剂量依赖(P<0.05)。结论AKBA可以抑制人结肠癌细胞HCT-116的增殖和迁移,诱导细胞凋亡。这可能与其调控Wnt/β-catenin信号通路相关。

n-3多烯脂肪酸对血小板聚集、血栓形成、6-keto-PGF_(1α)/TXB_2比值的影响

国产马面鱼屯鱼油的ｎ－３多烯脂肪酸（ｎ－３ＰＵＦＡｓ）于１～３ｇ／Ｌ浓度能抑制ＡＡ、ＡＤＰ诱导的兔血小板聚集性，ｉｇ０．１５ｇ／ｋｇ能抑制大鼠体外血栓形成，并增加大鼠血浆６－ｋｅｔｏ－ＰＧＦ１α含量，提高６－ｋｅｔｏ－ＰＧＦ１α／ＴＸＢ２比值。

吡啶-2,6(1H,3H)二酮生物碱对兔血小板聚集和TXB_2,6-keto-PGF_(1α)产生的影响

目的 研究吡啶 - 2 ,6 (1H,3H)二酮生物碱 (SH1 )对二磷酸腺苷 (ADP) ,花生四烯酸 (AA)和胶原 (COL )诱导兔血小板聚集和 TXB2 和 6 - keto- PGF1α生成的影响 .方法 用比浊法和放射免疫法 .结果 SH1 0 .8～ 3.0 m mol·L- 1能显著地抑制 2 .0 μmol· L- 1 ADP,33.3μmol· L- 1 AA和 2 0 .0 g· L- 1 COL 诱导的兔血小板聚集并有良好的量效关系 .SH13 .0 mmol· L- 1 抑制 TXB2 产生 ,而增加 6 - keto- PGF1α产生 ,并因此 6 - keto- PGF1α和 TXB2 的比值增加 .结论 SH1 显著抑制血小板聚集和 TXB2 产生 ,同时增加 6 - keto- PGF1α产生 .

Oxalic acid catalyzed solvent-free one pot synthesis of coumarins

Oxalic acid was found to be an efficient catalyst for Pechmann condensation, which includes the reaction between phenols and β-keto esters leading to formation of coumarin derivatives. The advantages of present methods are the use of cheap and easy available catalyst, solvent-free reaction conditions, better yields and shorter reaction time.

Infant cholestasis patient with a novel missense mutation in the AKR1D1 gene successfully treated by early adequate supplementation with chenodeoxycholic acid: A case report and review of the literature

Steroid 5β-reductase [aldo-keto reductase family 1 member D1(AKR1D1)] is essential for bile acid biosynthesis. Bile acid deficiency caused by genetic defects in AKR1D1 leads to life-threatening neonatal hepatitis and cholestasis. There is still limited experience regarding the treatment of this disease. We describe an infant who presented with hyperbilirubinemia and coagulopathy but normal bile acid and γ-glutamyltransferase. Gene analysis was performed using genomic DNA from peripheral lymphocytes from the patient, his parents, and his elder brother. The patient was compound heterozygous for c.919C>T in exon 8 and exhibited a loss of heterozygosity of the AKR1D1 gene, which led to an amino acid substitution of arginine by cysteine at amino acid position 307(p.R307C). Based on these mutations, the patient was confirmed to have primary 5β-reductase deficiency. Ursodeoxycholic acid(UDCA) treatment did not have any effect on the patient. However, when we changed to chenodeoxycholic acid(CDCA) treatment, his symptoms and laboratory tests gradually improved. It is therefore crucial to supplement with an adequate dose of CDCA early to improve clinical symptoms and to normalize laboratory tests.

Silica-bonded S-sulfonic acid a recyclable catalyst for the synthesis of coumarins

Silica-bonded S-sulfonic acid （SBSSA） was prepared by the reaction of 3-mercaptopropylsilica （MPS） and chlorosulfonic acid in chloroform. This solid acid has been employed as a recyclable catalyst for the synthesis of coumarins from phenols and β-keto- esters at 80 ℃ under solvent-free conditions.

猪支链氨基酸的代谢、互作及理想模式

支链氨基酸是蛋白质中常见的氨基酸,包括亮氨酸、异亮氨酸和缬氨酸。由于支链氨基转移酶和支链α-酮酸脱氢酶是三种支链氨基酸代谢通路的共同酶,因此,支链氨基酸之间存在拮抗作用。这两种酶最有效的激活因子是亮氨酸及其代谢产物α-酮异己酸。日粮中过高的亮氨酸,会增加肌肉的分解代谢,影响猪的生长性能。因此,保育猪阶段,建议标准回肠可消化赖氨酸∶亮氨酸∶异亮氨酸∶缬氨酸的理想模式为100∶100~150∶50~60∶65~70;生长育肥猪阶段,建议标准回肠可消化赖氨酸∶亮氨酸∶异亮氨酸∶缬氨酸的理想模式为100∶110~150∶45~55∶65~75。