Comparison of the Δ^(12) fatty acid desaturase gene between high-oleic and normal-oleic peanut genotypes

△^12 fatty acid desaturase gene has been targeted as a logical candidate controlling the high oleate trait in peanut seeds. By RT-PCR method, the full-length cDNAs of △^12 fatty acid desaturase gene were isolated from peanut （Arachis hypogaea L.） genotypes with normal and high ratio of oleic to linoleic acid, which were designated AhFAD2B and AhFAD2B＇, respectively. Sequence alignment of their coding regions revealed that an extra A was inserted at the position ＋442 bp of AhFAD2B＇ sequence of high oleic acid genotypes, which resulted in the shift of open reading frame and a truncated protein AhFAD2B＇, with the loss of one histidine box involved in metal ion complex required for the reduction of oxygen. Analysis of transcript level showed that the expression of △^12 fatty acid desaturase gene in high oleic acid genotype was slightly lower than that in normal genotype. The enzyme activity experiment of yeast （Saccharomyces cerevisiae） cell transformed with AhFAD2B or AhFAD2B＇ proved that only AhFAD2B gene product showed significant △^12 fatty acid desaturase activity, but AhFAD2B＇ gene product did not. These results suggested that the change of AhFAD2B＇ gene sequence resulted in lower activity or deactivation of △^12 fatty acid desaturase in high oleic acid genotype.

Identification and Functional Characterization of a NovelΔ12 Fatty Acid Desaturase Gene from Haematococcus pluvialis

The freshwater microalga Haematococcus pluvialis accumulates large amounts of fatty acids in response to adverse conditions.However,the key fatty acid desaturase genes in H.pluvialis remain unknown.In this study,we cloned and functionally characterized aΔ12 fatty acid desaturase gene,and designated it as HpFAD2.The open reading frame of HpFAD2 consisted of 1137 base pairs and encoded 378 amino acids.The deduced polypeptide showed 70%identity to other endoplasmic reticulumΔ12 fatty acid desaturases,whereas it had only 44%identity to plastidΔ12 fatty acid desaturases.The PSORT algorithm and phylogenetic analysis further confirmed its affiliation to the endoplasmic reticulumΔ12 fatty acid desaturases.Heterologous expression was performed in Saccharomyces cerevisiae cells transformed with the recombinant plasmid pYES2-HpFAD2.Two additional fatty acids(C16:2 and C18:2)were detected in the yeast transformants.The results indicatedΔ12 desaturation activity and substrate preference for C18:1 over C16:1.The transcriptional levels of H.pluvialis HpFAD2 at different growth stages were measured by quantitative polymerase chain reaction(PCR),indicating that the HpFAD2 transcriptional levels were significantly higher in red cells than those in green cells.Our study brings more insight into the fatty acid biosynthetic pathway of H.pluvialis.

Production of γ-linolenic acid and stearidonic acid by Synechococcus sp.PCC7002 containing cyanobacterial fatty acid desaturase genes

Genetic modifi cation is useful for improving the nutritional qualities of cyanobacteria. To increase the total unsaturated fatty acid content, along with the ratio of ω-3/ω-6 fatty acids, genetic engineering can be used to modify fatty acid metabolism. S ynechococcus sp. PCC7002, a fast-growing cyanobacterium, does not contain a Δ6 desaturase gene and is therefore unable to synthesize γ-linolenic acid(GLA) and stearidonic acid(SDA), which are important in human health. In this work, we constructed recombinant vectors Syd6 D, Syd15 D and Syd6Dd15 D to express the Δ15 desaturase and Δ6 desaturase genes from Synechocystis PCC6803 in Synechococcus sp. PCC7002, with the aim of expressing polyunsaturated fatty acids. Overexpression of the Δ15 desaturase gene in S ynechococcus resulted in 5.4 times greater accumulation of α-linolenic acid compared with the wild-type while Δ6 desaturase gene expression produced both GLA and SDA. Co-expression of the two genes resulted in low-level accumulation of GLA but much larger amounts of SDA, accounting for as much to 11.64% of the total fatty acid content.

Identification and characterization of a delta-12 fatty acid desaturase gene from marine microalgae Isochrysis galbana

The cDNA of the delta-12 fatty acid desaturase gene, IgFAD2, was cloned from the marine microalgae Isochrysis galbana, a species capable of producing docosahexaenoic acid. Sequence analysis indicated that the open reading frame measured a length of 1 158 bp and encoded 386 amino acids with a predicted molecular weight of 42.8 kDa and an isoelectric point of 9.2. Computational analysis of the protein sequence of IgFAD2 showed typical features of membrane-bound desaturase such as three conserved histidine boxes along with four membranespanning regions that were universally present among plant desaturases. Quantitative real-time PCR results showed that the abundance of IgFAD2 transcript was significantly upregulated under different environmental stresses including low temperature(15℃), high salinity(salinity of 62 and 93), and nitrogen starvation(220 μmol/L). Heterologous expression indicated that yeast cells transformed with a plasmid construct containing IgFAD2 could convert endogenous oleic acid(18:1^(?9), OA) into linoleic acid(18:2^(?9, 12), LA). These findings confirm that I. galbana IgFAD2 plays important roles in the biosynthetic pathways of unsaturated fatty acids.

Functional characterization of a Δ6 fatty acid desaturase gene and its 5′-upstream region cloned from the arachidonic acid-rich microalga Myrmecia incisa Reisigl(Chlorophyta)

It is suggested that Δ6 fatty acid desaturase(FAD) plays a critical role in the biosynthesis of polyunsaturated fatty acids in plants and microalgae. But why does it adapt to the changed environments such as nitrogen starvation is seldom understood. One Δ6 FAD gene( MiD6 fad) from an arachidonic acidrich microalga M yrmecia incisa Reisigl(Chlorophyta) was first heterologously expressed in S accharomyces cerevisiae for the identification of function. The fatty acid profile of transgenic yeast detected by gas chromatography-mass spectrometry illustrated that the enzyme MiD6 FAD could convert linoleic and ?-linolenic acids to γ-linolenic and stearidonic acids, respectively, demonstrating that M iD6 fad encoded a Δ6 FAD. A 1 965-bp fragment of the cloned 2 347-bp 5′-upstream region of M iD6 fad was next subcloned and fused upstream with green fluorescent protein(GFP) gene to replace the GAL1 promoter of the vector pYES2. The generated construct was transformed into S. cerevisiae for function determination. Confocal microscopic images of the transformed line illustrated that this inserted fragment could drive GFP expression, which was further verified by fluorescence intensity quantification and Western blot analysis using antiGFP antibody. The conversion efficiency(approximately 2%-3%) of MiD6 FAD was much lower than the reported ? 3 FAD and Δ6 elongase in this microalga, suggesting that MiD6 FAD catalysed the possible ratelimiting step for ArA biosynthesis. The presence of several putative c is-acting regulatory elements in this identified promoter sheds new light on the regulation mechanism research of Δ6 FAD transcription for the ArA production in M. incisa in changing environmental factors.

Cloning and molecular characterization of△^(12)-fatty acid desaturase gene from Mortierella isabellina

瞄准：克隆三角洲(12 ) Mortierella isabellina 并且到的丰满的酸 desaturase 基因机能上地描绘这基因在试管内和在活体内。方法：反向的 transcriptional 聚合酶链反应(RT-PCR ) 被用来克隆三角洲(12 ) 的开的读物框架 Mortierella isabellina 的丰满的酸 desaturase 基因(D12D ) 。Plasmids pEMICL12 和 pYMICL12 与它被构造。pEMICL12 被转变成埃希氏杆菌属关口 i (E.coli ) 为在有 IPTG 的正式就职以后的表示的紧张 BL21 使用 CaCl (2 ) 方法。pTMICL12 在半乳糖的正式就职下面为表示用锂醋酸盐方法被转变成酿酒酵母紧张 INVSc1。北弄污方法被用来在 S.cerevisiae 紧张 INVSc1 在这基因的 transcriptional 水平上调查温度的效果。结果：Recombinant 原生质标志 pEMICL12 和 pTMICL12 成功地被构造并且与适当方法独立转变了成 E.coli 和 S.cerevisiae。在有 IPTG 和半乳糖的正式就职以后，它被发现三角洲(12 ) 的那表情在 E.coli 和 S 的丰满的酸 desaturase 基因。在导致的适当条件下面的啤酒活跃三角洲(12 ) 的生产丰满的酸 desaturase，它能由 GCMS 察觉在试管内和在活体内分别地把 17.876% 油酸和 17.604% 变换成亚油酸。结论：克隆并且在 E.coli 和 S.cerevisiae 的 M.isabellina D12D 基因的表示成功地被完成。

Association of Bovine Fatty Acid Desaturase 2 Gene Single-Nucleotide Polymorphisms with Intramuscular Fatty Acid Composition in Japanese Black Steers

Beef from Japanese Black cattle (JBK), is popular in Japan and valued for its highly marbled fat content. In JBK, genes affecting oleic acid content in meat have been studied mainly to lower the fat melting point and improve tenderness;however, there has been no direct correlation demonstrated between beef taste and oleic acid. To investigate genes affecting other fatty acids other than oleic acid, polymorphisms of the fatty acid desaturase 2 (FADS2) gene were genotyped and associations with fatty acid profile in JBK beef were investigated. Amplifications of 5’-flanking regions, 12 exons, and 3’-untranslated regions of the FADS2 gene in three Japanese and five Western cattle breeds via PCR, were amplified, sequenced and SNPs were identified using specific TaqMan genotyping assay. Fatty acid composition of intramuscular adipose tissue of the Trapezius muscle was analyzed in JBK steers. Six of the 15 identified SNPs are novel and have never been registered in any public bovine SNP database. A non-synonymous SNP (rs211580559;C > T;294 Ala > Val) in exon 7 was examined in order to evaluate its association with fatty acid profiles. The data showed that highly significant association existed between rs211580559 and C18:2 (n-6) composition, and accounted for 22.3% of the variation. There were no significant relationships between rs2115-80559 and the other fatty acids. It was concluded that rs211580559 of the FADS2 gene may be a useful selection marker for reducing unfavorable volatiles generated from linoleic acid in JBK beef during the cooking process.

Origin and evolution of fatty acid desaturase genes in oil crop Brassica napus

Fatty acid(FA)desaturases,as the key enzymes in lipid metabolism,are responsible for biosynthesis of the unsaturated fatty FAs,which play important roles in maintaining cell membrane integrity and multiple stress responses.Although attention has been drawn to some plant FA desaturase genes,their global landscape in oil crops is still lacking.Here,we performed systematic characterization and phylogenomic synteny network analyses of the FA desaturase gene family in polyploid oil crop B.napus and other 54 species covering major streptophyte lineages.A total of 1653 FA desaturase genes were identified from these plant genomes.Based on the broad-scale family phylogeny and functional domains,we proposed a unified eight-group classification system for angiosperm FA desaturases,and found that the origin of genes responsible for FA desaturation evolved early and some genes were absent in different species.Phylogenomic analyses revealed deeply conserved syntenic relationships within each of the eight FA desaturase groups.B.napus contains up to 93 FA desaturase genes from the eight groups.Recurrent duplication events in Brassicaceae contributed to the expansion of FA desaturase genes in B.napus,leading to further functional diversification.These FA desaturase genes exhibited spatio-temporal specific expression patterns in different tissues of B.napus,and a set of FA desaturase genes seem to be orchestrated by key transcriptional factors during seed development,such as zf-HD,B3,GATA3,PEI1,NFYA7,YAB1 and YAB2.Altogether,our data have inferred the evolutionary trajectory of this important gene family across distinct plant lineages,providing theoretical basis for future manipulation of FA desaturase genes to improve the seed oil quality of B.napus.

血清H-FABP、GDF-15表达对STEMI患者PCI后不良心血管事件的预测价值

目的:探究血清心型脂肪酸结合蛋白(heart-type fatty acid binding protein,H-FABP)、生长分化因子-15(growth and differentiation factor-15,GDF-15)表达对ST段抬高型心肌梗死(ST-segment elevation myocardial infarction,STEMI)患者经皮冠状动脉介入治疗(percutaneous coronary intervention,PCI)后不良心血管事件发生的预测价值。方法:采用前瞻性研究,选择2020年6月—2023年6月于赣州市人民医院接受PCI的140例STEMI患者作为研究对象,术前检测患者血清H-FABP、GDF-15,行PCI,术后随访3个月,统计患者术后不良心血管事件发生情况,分析血清H-FABP、GDF-15与STEMI患者术后不良心血管事件发生的关系,同时绘制受试者工作特征(receiver operating characteristic,ROC)曲线,探究血清H-FABP、GDF-15对STEMI患者PCI后不良心血管事件发生的预测价值。结果:随访3个月期间,140例患者均无脱落病例;随访期间,140例STEMI患者PCI后发生不良心血管事件占比为23.57%(33/140),未发生不良心血管事件占比为76.43%(107/140)。两组心肌梗死面积、高血压、既往吸烟史比较,差异均有统计学意义(P<0.05);两组性别、年龄、病变支数、既往饮酒史、肌红蛋白(myoglobin,Myo)、心肌肌钙蛋白I(cardiac troponin I,cTnI)、肌酸激酶同工酶(creatine kinase-MB,CK-MB)、心室舒张末期内径(left ventricular end diastolic dimension,LVEDD)比较,差异均无统计学意义(P>0.05)。发生组血清H-FABP、GDF-15均高于未发生组,差异均有统计学意义(P<0.05)。点二列相关性分析显示,血清H-FABP、GDF-15与STEMI患者PCI后不良心血管事件发生呈正相关(r>0,P<0.05)。ROC曲线结果显示,血清H-FABP、GDF-15单独预测的AUC>0.7,联合预测的AUC>0.8,联合预测价值更高。结论:STEMI患者PCI前血清H-FABP、GDF-15水平越高,术后不良心血管事件发生风险越大,且临床可以将血清H-FABP、GDF-15作为STEMI患者PCI后不良心血管事件发生的有效预测指标。

Cloning and characterization of a stearoyl-ACP desaturase gene from Jatropha curcas

Using degenerate primers and RT-PCR, RACE techniques, a 1491 bp cDNA segment of stearoyl-acyl carrier protein desaturase （SAD） is cloned from developing seeds of Jatropha curcas L. The segment contains a 1191 bp of complete open reading frame （ORF）. Analysis in the BLAST on NCBI shows that Jatropha curcas SAD （JSAD） gene encodes a protein precursor composed of a signal peptide of 33 amino acids and a mature peptide of 363 amino acids. The homological analysis shows that JSAD has high level of homology both in nucleotide sequence and in amino acid sequence to other plants SADs. The nucleotide and peptide identity of JSAD to Ricinus communis SAD （RSAD） is up to 89% and 96.2% respectively. Molecular modeling of JSAD indicates that its three-dimensional structure strongly resembled the crystal structure of RSAD.

Improved method for measuring the δ15N compound-specific amino acids: Application on mesopelagic fishes in the South China Sea

Compound-specific stable isotope analysis of individual amino acids(CSIA-AA)has been widely used in ecological and biogeochemical studies.It has been proven to be powerful in tracing the diet sources and trophic interactions.However,assessing the N sources of mesopelagic fishes has been inconclusive because the mesopelagic fishes’unique domain(water depth ranged from 0 to 1000 m)and unresolved nitrogen isotopes of various forms.This study proposes a new method for coupling instruments(ion chromatography and PreconIRMS)and chemical method of oxidation-reduction of amino acids,and also combinedδ15N of AAs withδ13C of fatty acids(FAs)to analyze the trophic interactions of mesopelagic fishes in the South China Sea(SCS).AAs were isolated by ion chromatography with high peak resolution and collected by an automated fraction collector.The chemical method then converted the AAs into N2 O with a robust oxidation yields and suitable molar ratio of NH2 OH to.Finally,theδ15N of AAs at 20 nmol were measured with a reasonable precision(<0.6‰).With this method,this study report the first batch high precisionδ15N of AAs andδ13C of FAs of mesopelagic fishes collected from SCS.Diaphus luetkeni,Chauliodus minimus and Bathygadus antrodes showed similarδ13C values of 20:4 n-6(~-28‰),while Argyropelecus affinis and Stomias had similar values(~-32‰).These results reflect that mesopelagic fishes had complex diet sources.An increase of 4‰inδ15N of glutamic acid(Glu)was found between piscivorous and planktivorous fishes,which might suggest a trophic discrimination factor of mesopelagic fishes in the SCS.This study usedδ13C of 20:4 n-6 to reveal the diet sources of mesopelagic fishes andδ15N of Glu to clarify trophic level between piscivorous and planktivorous fishes.Thus,this combinative method could therefore ultimately be applied in a variety of deep-sea ecosystem.

Effect of Dietary Lipid on the Growth, Fatty Acid Composition and Δ5 Fads Expression of Abalone(Haliotis discus hannai Ino) Hepatopancreas

This study investigated the effect of dietary lipid on the growth, fatty acid composition and Δ5 fatty acyl desaturase genes(Fads) expression of juvenile abalone(Haliotis discus hannai Ino) hepatopancreas. Six purified diets were formulated to contain tripalmitin(TP), olive oil(OO, 72.87% 18:1n-9), grape seed oil(GO, 68.67% 18:2n-6), linseed oil(LO, 70.48% 18:3n-3), ARA oil(AO, 41.81% ARA) or EPA oil(EO, 44.09% EPA and 23.67% DAH). No significant difference in survival rate was observed among abalone fed with different diets. Weight gain rate(WGR) and daily growth rate of shell length(DGRSL) were significantly increased in abalone fed with diets containing OO, AO and EO, but decreased in abalone fed with LO diet(P < 0.05) in comparison with those fed with TP. High level of dietary 18:2n-6 resulted in higher content of n-6 polyunsaturated fatty acids(PUFAs) in abalone fed with GO than those fed with TP, OO, LO and EO(P < 0.05). n-3 PUFAs in abalone fed with LO was significantly higher than those in abalone fed with TP, OO, GO and AO(P < 0.05). The highest contents of 20:1n-9 and 22:1n-9 were observed in abalone fed with OO. The expression of Δ5 Fads in hepatopancreas of abalone was enhanced by high concentration of 18:3n-3 and suppressed by dietary LC-PUFAs; however it was not affected by dietary high concentration of 18:1n-9 or 18:2n-6. These results provided valuable information for understanding the synthesis of LC-PUFAs and nutritional regulation of Δ5 Fads expression in abalone.

Roles of vitamin A in the regulation of fatty acid synthesis

Dietary macronutrients and micronutrients play important roles in human health.On the other hand,the excessive energy derived from food is stored in the form of triacylglycerol.A variety of dietary and hormonal factors affect this process through the regulation of the activities and expression levels of those key player enzymes involved in fatty acid biosynthesis such as acetyl-CoA carboxylase,fatty acid synthase,fatty acid elongases,and desaturases.As a micronutrient,vitamin A is essential for the health of humans.Recently,vitamin A has been shown to play a role in the regulation of glucose and lipid metabolism.This review summarizes recent research progresses about the roles of vitamin A in fatty acid synthesis.It focuses on the effects of vitamin A on the activities and expression levels of mRNA and proteins of key enzymes for fatty acid synthesis in vitro and in vivo.It appears that vitamin A status and its signaling pathway regulate the expression levels of enzymes involved in fatty acid synthesis.Future research directions are also discussed.

血清H-FABP、GDF-15、sICAM-1与PCI后心肌损伤的关系分析

目的分析冠心病相关血清指标心型脂肪酸结合蛋白(H-FABP)、生长分化因子15(GDF-15)、可溶性细胞间黏附分子-1(sICAM-1)与经皮冠状动脉介入术(PCI)后心肌损伤的关系。方法回顾性选取2020年3月至2022年3月在本院接受PCI治疗的200例冠心病患者为研究对象,根据术后3个月是否出现心肌损伤,将其分为心肌损伤组(n=42)和心肌未损伤组(n=158)。比较2组各项临床资料及血清H-FABP、GDF-15、sICAM-1等实验室指标水平,并采用受试者工作特征(ROC)曲线分析以上指标与冠心病患者PCI后心肌损伤的关系。结果心肌损伤组患者从发病到治疗时间明显长于心肌未损伤组,血清H-FABP、GDF-15、sICAM-1水平均高于心肌未损伤组(P<0.05)。建立相关性模型,结果显示,PCI后心肌受损与从发病到治疗时间相关性较弱(r=0.168,P<0.05),与血清H-FABP、GDF-15、sICAM-1均存在中等程度相关(r=0.424、0.403、0.442,P<0.05)。ROC曲线模型显示,血清H-FABP、GDF-15、sICAM-1均对PCI后心肌损伤具有一般诊断效能,三项联合检测具有较高准确性,其诊断AUC、约登指数、灵敏度、特异性分别为0.912、0.585、95.24%、63.29%。结论血清H-FABP、GDF-15、sICAM-1与冠心病患者PCI后心肌损伤的发生密切相关,三项血液指标联合检测对心肌损伤具有较高诊断和预测价值。

GDF-15基因多态性、膳食与中心性肥胖的相关性研究

目的:探究GDF-15基因多态性与膳食因素的交互作用及其与中心性肥胖的关联。方法:采用Sequenom MassArray系统对GDF-15基因多态性分型。使用食物频率问卷(FFQ)法调查膳食摄入情况。应用Logistic回归分析SNP位点、膳食因素及两者间交互作用与中心性肥胖的关联。结果:Logistics回归分析显示,携带GDF-15基因rs1059519CG基因型人群患中心性肥胖的风险高于携带GDF-15基因rs1059519GG基因型人群,OR为1.986(95%CI:1.011~3.900,P<0.05)。饱和脂肪酸、多不饱和脂肪酸的中等摄入量与中心性肥胖的风险相关,OR分别为1.983(95%CI:1.139~3.451,P<0.05)和2.146(95%CI:1.238~3.719,P<0.05)。rs1059519CG基因型与饱和脂肪酸、多不饱和脂肪酸中等摄入量的交互作用会增加中心性肥胖的风险,OR分别为2.737(95%CI:1.241~4.536,P<0.05)和2.852(95%CI:1.540~5.281,P<0.05)。结论:GDF-15基因多态性、饱和脂肪酸、多不饱和脂肪酸摄入及两者间交互作用与中心性肥胖相关。

西农萨能羊乳腺脂肪酸合酶基因exon 9-15的克隆与序列分析

【目的】山羊FAS基因exon 9-15编码的乙酰/丙二酸单酰基转移酶(acetyl-CoA and malonyl-CoA transacylases,AT/MT)区域对山羊乳短、中链脂肪酸的合成起重要调控作用。本研究针对西农萨能羊乳腺FAS基因exon 9-15进行克隆和序列分析。【方法】以处于泌乳期28d的西农萨能羊乳腺组织mRNA反转录的cDNA为模板,通过RT-PCR方法首次扩增出西农萨能羊乳腺FAS基因exon 9-15的cDNA序列全长及exon 8的3′端和exon 16的5′端部分cDNA序列(GenBank收录号为DQ915966),并对其进行了同源性分析和功能预测。【结果】克隆片段全长1449bp,其中包括exon 9-15共1388bp、exon 8的3′端9bp和exon 16的5′端52bp,编码483个氨基酸,包含编码的AT/MT区域951bp(454～1404nt);西农萨能羊乳腺FAS基因exon 9-15与牛(NM_001012669),人(NM_004104),大鼠(NM_017332)和鸡(NM_205155)核苷酸序列相似度分别为95%、85.7%、82.7%、73.2%,氨基酸相似度分别为92.9%、77.7%、82.3%、64.7%;exon 10较其它物种缺失1个氨基酸。【结论】克隆获得西农萨能羊FAS基因片段全长1449bp,外显子9-15大小分别为463、185、190、95、135、204和116bp;核苷酸及氨基酸序列与牛相应序列的同源性均高于其它物种;AT/MT区域的活性位点在各物种间均为高度保守的丝氨酸,但西农萨能羊exon 10较其它物种缺失1个氨基酸,这可能对AT/MT区域的空间构象及其生理功能产生重要影响。本研究为西农萨能羊FAS基因cDNA全长克隆以及基因功能研究奠定了重要基础。

过表达去饱和酶基因对大肠杆菌脂肪酸合成的影响

为获得高效产油脂工程菌株,在大肠杆菌(Escherichia coli)BL21(DE3)中表达了来自产油核桃内生菌枯草芽孢杆菌(Bacillus subtilis)HB1310的去饱和酶基因,构建了单基因表达菌株BL21(DE3)/pET-de1、BL21(DE3)/pET-de2及共表达菌株BL21(DE3)/pET-de。结果表明,去饱和酶基因在E.coliBL21(DE3)中实现了高水平的表达,3株工程菌的酶活性在60 h诱导过程中均高于野生菌株,尤以24 h的酶活性最高,分别为同时刻野生菌株的1.38、1.48倍和1.75倍。外源去饱和酶基因的过表达可引起E.coli中油脂产量和脂肪酸组分的变化,与野生菌相比,3株工程菌的油脂产量有较大提高,其发酵24 h的油脂产量分别可达0.57、0.58、0.72 g/L,其中,饱和脂肪酸含量分别提高72.26%、66.93%、123.21%,不饱和脂肪酸含量分别提高112.18%、44.18%、134.30%。本研究可为产油脂工程菌的开发和应用提供有价值的菌种来源。

H-FABP、miRNA-21、GDF15对急性胸痛的预测价值研究

目的分析心型脂肪酸结合蛋白(heart type-fatty acid binding protein,H-FABP)、微小RNA-21(microRNA-21,miRNA-21)、生长分化因子15(growth differentiation factor 15,GDF15)对急性胸痛的预测价值。方法选取急性胸痛患者600例作为观察组,同期选取体检人员600例作为对照组,采用酶联免疫吸附实验检测2组受试者血清H-FABP、miRNA-21、GDF15,受试者特征曲线(receiver operator characteristics curve,ROC)分析H-FABP、miRNA-21、GDF15对急性胸痛的预测价值。结果急性胸痛组H-FABP、GDF15、miRNA-21水平高于对照组(P<0.05);与轻度相比,中、重度患者H-FABP、miRNA-21、GDF15水平升高(P<0.05),与中度相比,重度患者H-FABP、miRNA-21、GDF15水平升高(P<0.05)。改良的早期预警评分(modified early warning score,MEWS)评分≥7、HEART评分≥5、肾功能下降患者H-FABP、miRNA-21、GDF15表达水平较高(P<0.05)。ROC分析H-FABP、miRNA-21、GDF15诊断急性胸痛灵敏度低于三项联合(0.692、0.726、0.785、0.867)。结论H-FABP、miRNA-21、GDF15在急性胸痛患者血清中高表达,测定H-FABP、miRNA-21、GDF15变化对急性胸痛患者病情预测具有意义。

湘油15号芥酸合成酶基因fae1的克隆与序列分析

根据GenBank中脂肪酸延长酶基因fae1序列(AY888037)设计了PCR扩增引物,以甘蓝型油菜品种湘油15号总DNA为模板进行扩增,得到了扩增产物。测序结果表明,该片段长度为1 642 bp,经序列分析表明,其氨基酸编码序列为1 425 bp,共编码475个氨基酸。BLAST分析结果表明,湘油15号中的fae1基因与其他芸薹属品系的fae1基因核苷酸同源性在66%～99%之间。氨基酸序列比对结果表明,高芥酸油菜品种fae1在第206位缺失了1个Thr,且甘蓝型油菜比白菜型油菜在羧基末端要多出7～16个氨基酸,这些核苷酸序列差异以及某些关键氨基酸的改变有可能是导致不同油菜品种中芥酸含量变异的原因。

Δ12/Δ15脂肪酸脱饱和酶在发酵食品中应用的研究进展

Δ12/Δ15脂肪酸脱饱和酶在多不饱和脂肪酸合成中起重要作用,是生物体参与脂肪酸代谢途径的关键脱饱和酶类。脂肪酸在发酵食品中益生作用分析成为功能性脂质研究领域的热点话题,调控脂肪酸合成的Δ12/Δ15脂肪酸脱饱和酶应用的研究意义重大。本文首先介绍了Δ12/Δ15脂肪酸脱饱和酶及其参与的脂肪酸代谢途径,其次从植物、动物、细菌、酵母菌、霉菌和藻类6个方面简述Δ12/Δ15脂肪酸脱饱和酶来源,综述了Δ12/Δ15脂肪酸脱饱和酶在发酵食品应用中的研究,旨在为Δ12/Δ15脂肪酸脱饱和酶研究提供一定的理论参考,为Δ12/Δ15脂肪酸脱饱和酶在发酵食品工业的应用提供新思路。