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Plastidial Δ12 fatty acid desaturase (FAD6) is a key enzyme for linoleic acid (LA) and α-linolenic acid (ALA) biosynthesis. Chia (Salvia hispanica L.) is a revived omega-3 plant source that is richest in ALA level. In this study, based on the RACE method, one full-length cDNA sequence encoding FAD6, named ShFAD6, was isolated from chia. There exist three alternative transcription start sites and five alternative poly(A) tailing sites in ShFAD6. The 5′UTR of ShFAD6 contains a purine-stretch of 44 bp. ShFAD6 has an ORF of 1335 bp encoding a 444 aa protein of 51.33 kDa. ShFAD6 contains a conserved Delta12-FADS-like domain together with three strong trans-membrane helices and three histidine motifs. There also exists a chloroplast transmit peptide in ShFAD6 N-terminal. Phylogenetic analyses validated its identity of dicot FAD6 protein and suggested some critical evolutionary features of plant FAD6 genes. Heterologous yeast expression confirmed the catalytic activity of ShFAD6. The qRT-PCR assay showed that ShFAD6 is mainly expressed in leaves, stems, flowers, buds and early-stage seeds, and also responded to various stresses and hormone treatments. Under Sclerotinia infection, qRT-PCR and fluorescence imaging illustrated the possible correlation of ShFAD6 expression and photosynthesis. This study provides insight for further function study of ShFAD6 in oil quality improvement in staple oilseed crops as well as stress response and adaptation in plants. [ABSTRACT FROM AUTHOR]

The plastidial delta-12 fatty acid desaturase (FAD6) plays a key role in linoleic acid (LA) and α-linolenic acid (ALA) biosynthesis. Perilla (Perilla frutescens) is an important oilseed crop with the highest ALA level. Here, using RACE PCR, two FAD6 cDNAs were cloned from perilla: the 1726 bp PfFAD6 and the 1881 bp PfFAD6’. PfFAD6 encodes a 443 aa protein, while PfFAD6’ is a pseudogene caused by premature stop codon mutation. N-terminal of PfFAD6 has a chloroplast transit peptide. PfFAD6 harbors an omega-6 FAD conserved domain, 2 trans-membrane helices and 3 histidine boxes. Phylogenetic analysis revealed some important evolutionary features of PfFAD6 and other plant FAD6 genes. Heterologous yeast expression showed that protein encoded by PfFAD6 can catalyze the production of LA. PfFAD6 was expressed in various organs at different levels, and responded to multiple biotic/abiotic stresses. The qRT-PCR assay and fluorescence imaging showed the correlation of PfFAD6 transcripts and photosynthetic activity under Sclerotinia infection. This study will lay a foundation for further function study of PfFAD6 in quality improvement in oilseed crops and plant-stress response. [ABSTRACT FROM AUTHOR]

In this study, the semitendinosus of horse meat was used as the raw material. The study assessed the variation of the tenderness of horse meat during postmortem aging through the injection of papain, bromelain and fungal protease. The cooking loss of the horse meat became worse during postmortem aging. Low concentration of protease improved water retention properties of horse meat. Papain, bromelain and fungal protease had significant influence on MFI and shear force. MFI increased obviously but the shear force decreased significantly with the addition of more protease (p <0.05). During postmortem aging, many small molecules popeptide appeared in treatment group. Myosin light chain 2, 20 KDa, 32 KDa and 75 KDa bands appeared at first, however later they disappeared in the group with high concentration of protease treatment in addition to the disappearance of Desmin and Troponin I. The muscle fiber, perimysium and endomysium were degraded because of papain, bromelain and fungal protease treatment. More muscle fiber fragments appeared during postmortem aging.Thus, the tenderness and eating quality of horse meat were improved by adding three kinds of protease. [ABSTRACT FROM AUTHOR]

The production of protein by alkali-solution and acid-isolation method will lead to the increase of salt in the feed liquid and affect its quality. In order to simplify the production of protein by the alkali acid precipitation process and obtain protein with high content and quality, the cation exchange resin was used to separate the walnut dreg protein. The desalination rate, protein content and recovery rate were used as indicators. Single factor experiments and response surface method were used to optimize the time used to isolate the protein from the cation exchange resin, the speed and temperature of the water bath shaker. Our results showed that the optimal time was determined at 62 min; the optimal speed of the water bath shaker was 120 rpm, and the optimal temperature was 49 °C. Under these conditions, the optimal protein recovery was 95.22% and the optimal protein content was 78.12%. [ABSTRACT FROM AUTHOR]

Brassica juncea is one of important oilseed crops, and FA compositions determine quality of vegetable oil. Although fatty acid desaturases (FADs) are mainly responsible for modifying seed FA compositions, genome-wide analysis of FAD gene family in B. juncea (BjuFAD) is not reported. Here, we identified 57 BjuFAD genes in B. juncea genome using homology searches. These FAD genes were unevenly distributed in 16 chromosomes and 3 scaffolds. Phylogenetic analysis showed that BjuFAD genes were divided into seven subfamilies. Exon–intron organizations, intron patterns and MEME motifs were highly conserved within each of BjuFAD subfamilies. Moreover, subcellular locations of deduced BjuFAD proteins and cis-acting elements in BjuFAD promoters were predicted and analyzed using online software. In addition, 16 SSR loci were totally found in BjuFAD genes/promoters. This work provides a basis for further function study of BjuFAD genes in quality improvement of B. juncea seed oil and in plant development as well as stress response. [ABSTRACT FROM AUTHOR]

Rapeseed ( Brassica napus) is an important oilseed crop worldwide, and fatty acid (FA) compositions determine the nutritional and economic value of its seed oil. Fatty acid desaturases (FADs) play a pivotal role in regulating FA compositions, but to date, no comprehensive genome-wide analysis of FAD gene family in rapeseed and its parent species has been reported. In this study, using homology searches, 84, 45, and 44 FAD genes were identified in rapeseed, Brassica rapa, and Brassica oleracea genomes, respectively. These FAD genes were unevenly located in 17 chromosomes and 2 scaffolds of rapeseed, 9 chromosomes and 1 scaffold of B. rapa, and all the chromosomes of B. oleracea. Phylogenetic analysis showed that the soluble and membrane-bound FADs in the three Brassica species were divided into four and six subfamilies, respectively. Generally, the soluble FADs contained two conserved histidine boxes, while three highly conserved histidine boxes were harbored in membrane-bound FADs. Exon-intron structure, intron phase, and motif composition and position were highly conserved in each FAD subfamily. Putative subcellular locations of FAD proteins in three Brassica species were consistent with those of corresponding known FADs. In total, 25 of simple sequence repeat (SSR) loci were found in FAD genes of the three Brassica species. Transcripts of selected FAD genes in the three species were examined in various organs/tissues or stress treatments from NCBI expressed sequence tag (EST) database. This study provides a critical molecular basis for quality improvement of rapeseed oil and facilitates our understanding of key roles of FAD genes in plant growth and development and stress response. [ABSTRACT FROM AUTHOR]

FATTY ACID DESATURASE 2 (FAD2, EC 1.3.1.35), also known as delta-12 oleate desaturase, is a key enzyme for linoleic acid and α-linolenic acid biosynthesis. Chia ( Salvia hispanica) seeds contain the highest known proportion of α-linolenic acid in any plant sources. In this study, two full-length FAD2 genes, named as ShFAD2- 1 and ShFAD2- 2, were isolated from S. hispanica based on RACE method. Both ShFAD2-1 and ShFAD2-2 proteins possess strong transmembrane helices, three histidine motifs and a C-terminal ER-located signal (YNNKL). Phylogenetic analysis showed that both ShFAD2- 1 and ShFAD2- 2 are grouped with constitutive plant FAD2s. Heterologous expression in Saccharomyces cerevisiae indicated that ShFAD2- 1 and ShFAD2- 2 genes both encode a bio-functional delta-12 oleate desaturase. ShFAD2- 2 was mainly expressed in flowers and early-stage seeds while ShFAD2- 1 expression was almost constitutive in different organs. qRT-PCR results demonstrated that ShFAD2- 1 and ShFAD2- 2 show a cold-induced and heat-repressed expression pattern, whereas they also were differentially up-regulated or repressed by other abiotic stresses. This is the first cloning and function characterization of FAD2 from S. hispanica, which can provide insights into molecular mechanism of high ALA traits of S. hispanica and enrich our understanding of the roles of FAD2 genes in various abiotic stresses. [ABSTRACT FROM AUTHOR]

∆12 fatty acid desaturase (FAD2) is a key enzyme for linoleic acid and linolenic acid biosynthesis. Perilla frutescens is a special oil plant species with highest linolenic acid content. In this study, based on RACE, two alleles for one FAD2 gene were isolated from P. frutescens cultivar C2: the 3956 bp PfFAD2a and the 3959 bp PfFAD2b, both with a full-length cDNA of 1526 bp, and both encoding a 382aa basic protein. The alleles have identities of over 98%, and their encoded proteins differ only by substitution of a strongly similar residue. Saccharomyces cerevisiae heterologous expression suggested that PfFAD2a/b both encode a bio-functional FAD2 enzyme. Phylogenetic analyses indicated that PfFAD2 shows the highest homologies to FAD2 genes from dicots such as Boraginaceae and Burseraceae. PfFAD2a/ b expressions are mainly restricted to developing seeds. PfFAD2a/b expression in the seedling leaf is upregulated by cold (4 °C) and repressed by heat (42 °C). Each of the eight cultivars contains two alleles for one PfFAD2 and 40 SNP sites are found. One allelic gene in cultivars C1 and P1 is pseudogene because of premature stop codon mutation in 5′ coding region. All other normal PfFAD2 genes/allelic genes encode identical or very similar proteins. PfFAD2a/ b expression level in developing seeds also varies among the eight cultivars. This study provides systemic molecular and functional features of PfFAD2 and enables its application in the study of plant fatty acids traits. [ABSTRACT FROM AUTHOR]

Rich nitrogen-doped mesoporous graphene (NDMG) with a large specific surface area of 496.8 m g and high electrical conductivity of 327.2 S cm, and suitable pore size was synthesized by a facile co-thermal annealing of pre-prepared phenolic polymer and dicyandiamide. The NDMG has a high nitrogen content (7.9 wt%) and can act as promising electroactive materials for two-electrode symmetric supercapacitors. The NDMG cells displayed a high specific capacitance of ca. 316 F g at 0.5 A g, which is much higher than that of the pristine graphene devices (ca. 123 F g). Moreover, compared with the capacitance drop rate of pristine graphene devices (8.9 %), the specific capacitance of NDMG cells was decreased by only 3.2 % after 2000 cycles, exhibiting a good cycling performance and reversibility. In addition, the specific capacitance of the NDMG cells can reach 251 F g at 5.0 A g, revealing an excellent rate capability and implying the ability to deliver a high energy density at a high power density. The good electrochemical performances of NDMG can be attributed to its high surface area, suitable mesopore size, and high electrical conductivity. [ABSTRACT FROM AUTHOR]