Cloning and characterisation of a Δ9 fatty acyl desaturase-like gene from the red claw crayfish (Cherax quadricarinatus) and its expression analysis under cold stress.

Desaturase is one of the key enzymes in the unsaturated fatty acid synthesis pathway. Δ9 desaturase catalyzes the synthesis of oleic acid from stearic acid by introducing double bonds in the 9th and 10th carbon chains, thereby increasing the content of MUFAs in the body. In order to explore the main function of the Δ9 desaturase gene under low temperature stress, RACE-PCR technology was used in this study to clone the full-length sequence of the CqFAD9-like from the hepatopancreas of red claw crayfish, Cherax quadricarinatus. The full length of the sequence is 1236 bp, and the open reading frame is 1041 bp, encoding 346 amino acid residues. The 5 'UTR is 116 bp, the 3' UTR is 79 bp, and the 3 'UTR contains a PloyA tail. The predicted theoretical isoelectric point and molecular weight are 8.68 and 40.28 kDa, respectively. Homology analysis showed that the sequence had the highest similarity with FAD9 from crustaceans. The results of real-time PCR showed that the expression level of this gene was highest in the hepatopancreas, which was significantly higher than other tissues, followed by the ovaries, brain ganglion and stomach. At the same time, the expression of the CqFAD9-like in hepatopancreas of crayfish cultured at 25, 20, 15 and 9 °C for four weeks was detected. The results showed that expression of the FAD9 gene increased gradually with decreasing temperature, indicating that metabolic desaturation might play a regulatory role during cold stress.

Membrane fluidization by alcohols inhibits DesK-DesR signalling in Bacillus subtilis.

After cold shock, the Bacillus subtilis desaturase Des introduces double bonds into the fatty acids of existing membrane phospholipids. The synthesis of Des is regulated exclusively by the two-component system DesK/DesR; DesK serves as a sensor of the state of the membrane and triggers Des synthesis after a decrease in membrane fluidity. The aim of our work is to investigate the biophysical changes in the membrane that are able to affect the DesK signalling state. Using linear alcohols (ethanol, propanol, butanol, hexanol, octanol) and benzyl alcohol, we were able to suppress Des synthesis after a temperature downshift. The changes in the biophysical properties of the membrane caused by alcohol addition were followed using membrane fluorescent probes and differential scanning calorimetry. We found that the membrane fluidization induced by alcohols was reflected in an increased hydration at the lipid-water interface. This is associated with a decrease in DesK activity. The addition of alcohol mimics a temperature increase, which can be measured isothermically by fluorescence anisotropy. The effect of alcohols on the membrane periphery is in line with the concept of the mechanism by which two hydrophilic motifs located at opposite ends of the transmembrane region of DesK, which work as a molecular caliper, sense temperature-dependent variations in membrane properties.

Heavy ion mutagenesis combined with triclosan screening provides a new strategy for improving the arachidonic acid yield in Mortierella alpina.

BACKGROUND: Arachidonic acid (ARA), which is a ω-6 polyunsaturated fatty acid, has a wide range of biological activities and is an essential component of cellular membranes in some human tissues. Mortierella alpina is the best strain for industrial production of ARA. To increase its yield of arachidonic acid, heavy ion beam irradiation mutagenesis of Mortierella alpina was carried out in combination with triclosan and octyl gallate treatment. RESULTS: The obtained mutant strain F-23 ultimately achieved an ARA yield of 5.26 g L- 1, which is 3.24 times higher than that of the wild-type strain. In addition, quantitative real-time PCR confirmed that the expression levels of fatty acid synthase (FAS), Δ5-desaturase, Δ6-desaturase, and Δ9-desaturase were all significantly up-regulated in the mutant F-23 strain, especially Δ6- and Δ9-desaturase, which were up-regulated 3- and 2-fold, respectively. CONCLUSIONS: This study confirmed a feasible mutagenesis breeding strategy for improving ARA production and provided a mutant of Mortierella alpina with high ARA yield.

mfat-1 transgene protects cultured adult neural stem cells against cobalt chloride-mediated hypoxic injury by activating Nrf2/ARE pathways.

Ischemic stroke is a devastating neurological disorder and one of the leading causes of death and serious disability in adults. Adult neural stem cell (NSC) replacement therapy is a promising treatment for both structural and functional neurological recovery. However, for the treatment to work, adult NSCs must be protected against hypoxic-ischemic damage in the ischemic penumbra. In the present study, we aimed to investigate the neuroprotective effects of the mfat-1 transgene on cobalt chloride (CoCl2 )-induced hypoxic-ischemic injury in cultured adult NSCs as well as its underlying mechanisms. The results show that in the CoCl2 -induced hypoxic-ischemic injury model, the mfat-1 transgene enhanced the viability of adult NSCs and suppressed CoCl2 -mediated apoptosis of adult NSCs. Additionally, the mfat-1 transgene promoted the proliferation of NSCs as shown by increased bromodeoxyuridine labeling of adult NSCs. This process was related to the reduction of reactive oxygen species. Quantitative real-time polymerase chain reaction and Western blot analysis revealed a much higher expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and its downstream genes (HO-1, NQO-1, GCLC). Taken together, our findings show that the mfat-1 transgene restored the CoCl2 -inhibited viability and proliferation of NSCs by activating nuclear factor erythroid 2-related factor 2 (Nrf2)/antioxidant response elements (ARE) signal pathway to inhibit oxidative stress injury. Further investigation of the function of the mfat-1 transgene in adult protective mechanisms may accelerate the development of adult NSC replacement therapy for ischemic stroke.

How did nature engineer the highest surface lipid accumulation among plants? Exceptional expression of acyl-lipid-associated genes for the assembly of extracellular triacylglycerol by Bayberry (Myrica pensylvanica) fruits.

Bayberry (Myrica pensylvanica) fruits are covered with a remarkably thick layer of crystalline wax consisting of triacylglycerol (TAG) and diacylglycerol (DAG) esterified exclusively with saturated fatty acids. As the only plant known to accumulate soluble glycerolipids as a major component of surface waxes, Bayberry represents a novel system to investigate neutral lipid biosynthesis and lipid secretion by vegetative plant cells. The assembly of Bayberry wax is distinct from conventional TAG and other surface waxes, and instead proceeds through a pathway related to cutin synthesis (Simpson and Ohlrogge, 2016). In this study, microscopic examination revealed that the fruit tissue that produces and secretes wax (Bayberry knobs) is fully developed before wax accumulates and that wax is secreted to the surface without cell disruption. Comparison of transcript expression to genetically related tissues (Bayberry leaves, M. rubra fruits), cutin-rich tomato and cherry fruit epidermis, and to oil-rich mesocarp and seeds, revealed exceptionally high expression of 13 transcripts for acyl-lipid metabolism together with down-regulation of fatty acid oxidases and desaturases. The predicted protein sequences of the most highly expressed lipid-related enzyme-encoding transcripts in Bayberry knobs are 100% identical to the sequences from Bayberry leaves, which do not produce surface DAG or TAG. Together, these results indicate that TAG biosynthesis and secretion in Bayberry is achieved by both up and down-regulation of a small subset of genes related to the biosynthesis of cutin and saturated fatty acids, and also implies that modifications in gene expression, rather than evolution of new gene functions, was the major mechanism by which Bayberry evolved its specialized lipid metabolism. This article is part of a Special Issue entitled: Plant Lipid Biology edited by Kent D. Chapman and Ivo Feussner.

Cytoprotective Effects and Mechanisms of Δ-17 Fatty Acid Desaturase in Injured Human Umbilical Vein Endothelial Cells (HUVECs).

BACKGROUND The beneficial effect of Δ-17 FAD is poorly understood. The aim of this study was to investigate the protective mechanism of fatty acids against atherosclerotic (AS) damage induced by oxidized low-density lipoprotein (ox-LDL) in human umbilical vein endothelial cells (HUVECs), and to identify the molecular mechanisms involved. MATERIAL AND METHODS The ox-LDL was used to induce lipotoxicity in HUVECs to establish a model of oxidative injury. HUVECs were transfected with Δ-17FAD lentivirus to induce cytoprotective effects. We evaluated the alterations in cell proliferation and apoptosis, and oxidative stress index, including levels of nitric oxide (NO), malonyldialdehyde (MDA), SOD enzyme, LDH, GSH-PX, and vascular endothelial growth factor (VEGF) expression. RESULTS The ox-LDL-induced excessive cellular apoptosis of HUVECs was abrogated by upregulation of Δ-17 FAD. Importantly, Δ-17 FAD converted ω-3 polyunsaturated fatty acid ARA into ω-6 polyunsaturated fatty acid EPA. Further, Δ-17 FAD overexpression promoted the proliferation of HUVECS, and inhibited ox-LDL-induced lipid peroxidation of HUVECs. The levels of nitric oxide, GSH-PX, and SOD enzyme were increased, and the activity of MDA and LDH was suppressed by the upregulation of Δ-17 FAD. In addition, upregulation of Δ-17 FAD significantly increased VEGF expression. In vitro tube formation assay showed that Δ-17 FAD significantly promoted angiogenesis. CONCLUSIONS These results suggest that Δ-17 fatty acid desaturase plays a beneficial role in the prevention of ox-LDL-induced cellular damage.

Biosynthetic mechanism of very long chain polyunsaturated fatty acids in Thraustochytrium sp. 26185.

Thraustochytrium, a unicellular marine protist, has been used as a commercial source of very long chain PUFAs (VLCPUFAs) such as DHA (22:6n-3). Our recent work indicates coexistence of a Δ4-desaturation-dependent pathway (aerobic) and a polyketide synthase-like PUFA synthase pathway (anaerobic) to synthesize the fatty acids in Thraustochytrium sp. 26185. Heterologous expression of the Thraustochytrium PUFA synthase along with a phosphopantetheinyl transferase in Escherichia coli showed the anaerobic pathway was highly active in the biosynthesis of VLCPUFAs. The amount of Δ4 desaturated VLCPUFAs produced reached about 18% of the total fatty acids in the transformant cells at day 6 in a time course of the induced expression. In Thraustochytrium, the expression level of the PUFA synthase gene was much higher than that of the Δ4 desaturase gene, and also highly correlated with the production of VLCPUFAs. On the other hand, Δ9 and Δ12 desaturations in the aerobic pathway were either ineffective or absent in the species, as evidenced by the genomic survey, heterologous expression of candidate genes, and in vivo feeding experiments. These results indicate that the anaerobic pathway is solely responsible for the biosynthesis for VLCPUFAs in Thraustochytrium.

A Caenorhabditis elegans model for ether lipid biosynthesis and function.

Ether lipids are widespread in nature, and they are structurally and functionally important components of membranes. The roundworm, Caenorhabditis elegans, synthesizes numerous lipid species containing alkyl and alkenyl ether bonds. We isolated C. elegans strains carrying loss-of-function mutations in three genes encoding the proteins required for the initial three steps in the ether lipid biosynthetic pathway, FARD-1/FAR1, ACL-7/GNPAT, and ADS-1/AGPS. Analysis of the mutant strains show that they lack ether lipids, but possess the ability to alter their lipid composition in response to lack of ether lipids. We found that increases in de novo fatty acid synthesis and reduction of stearoyl- and palmitoyl-CoA desaturase activity, processes that are at least partially regulated transcriptionally, mediate the altered lipid composition in ether lipid-deficient mutants. Phenotypic analysis demonstrated the importance of ether lipids for optimal fertility, lifespan, survival at cold temperatures, and resistance to oxidative stress.Caenorhabditis.

Compensatory induction of Fads1 gene expression in heterozygous Fads2-null mice and by diet with a high n-6/n-3 PUFA ratio.

In mammals, because they share a single synthetic pathway, n-6/n-3 ratios of dietary PUFAs impact tissue arachidonic acid (ARA) and DHA content. Likewise, SNPs in the human fatty acid desaturase (FADS) gene cluster impact tissue ARA and DHA. Here we tested the feasibility of using heterozygous Fads2-null-mice (HET) as an animal model of human FADS polymorphisms. WT and HET mice were fed diets with linoleate/α-linolenate ratios of 1:1, 7:1, and 44:1 at 7% of diet. In WT liver, ARA and DHA in phospholipids varied >2× among dietary groups, reflecting precursor ratios. Unexpectedly, ARA content was only <10% lower in HET than in WT livers, when fed the 44:1 diet, likely due to increased Fads1 mRNA in response to reduced Fads2 mRNA in HET. Consistent with the RNA data, C20:3n-6, which is elevated in minor FADS haplotypes in humans, was lower in HET than WT. Diet and genotype had little effect on brain PUFAs even though brain Fads2 mRNA was low in HET. No differences in cytokine mRNA were found among groups under unstimulated conditions. In conclusion, differential PUFA profiles between HET mice and human FADS SNPs suggest low expression of both FADS1 and 2 genes in human minor haplotypes.

Fads1 and 2 are promoted to meet instant need for long-chain polyunsaturated fatty acids in goose fatty liver.

Global prevalence of non-alcoholic fatty liver disease (NAFLD) constitutes a threat to human health. Goose is a unique model of NAFLD for discovering therapeutic targets as its liver can develop severe steatosis without overt injury. Fatty acid desaturase (Fads) is a potential therapeutic target as Fads expression and mutations are associated with liver fat. Here, we hypothesized that Fads was promoted to provide a protection for goose fatty liver. To test this, goose Fads1 and Fads2 were sequenced. Fads1/2/6 expression was determined in goose liver and primary hepatocytes by quantitative PCR. Liver fatty acid composition was also analyzed by gas chromatography. Data indicated that hepatic Fads1/2/6 expression was gradually increased with the time of overfeeding. In contrast, trans-C18:1n9 fatty acid (Fads inhibitor) was reduced. However, enhanced Fads capacity for long-chain polyunsaturated fatty acid (LC-PUFA) synthesis was not sufficient to compensate for the depleted LC-PUFAs in goose fatty liver. Moreover, cell studies showed that Fads1/2/6 expression was regulated by fatty liver-associated factors. Together, these findings suggest Fads1/2 as protective components are promoted to meet instant need for LC-PUFAs in goose fatty liver, and we propose this is required for severe hepatic steatosis without liver injury.

Efficient generation of sFat-1 transgenic rabbits rich in n-3 polyunsaturated fatty acids by intracytoplasmic sperm injection.

N-3 polyunsaturated fatty acids (n-3 PUFAs) have their first double bond at the third carbon from the methyl end of the fatty-acid chain and had been proven to be beneficial to human health. However, mammals cannot produce n-3 PUFAs by themselves because they lack the n-3 fatty-acid desaturase (Fat-1) gene. Thus, the possibility of producing sFat-1 transgenic rabbits was explored in this study. The transgenic cassette of pPGK1-sFat-1-CMV-EGFP was constructed and transgenic rabbit embryos were produced by intracytoplasmic sperm injection (ICSI). When 123 EGFP-positive embryos at the 2-8-cell stage were transplanted into the oviduct of four oestrous-synchronised recipients, two of them became pregnant and gave birth to seven pups. However, transfer of embryos into the uterus of oestrous-synchronised recipients and oviduct or uterus of oocyte donor rabbits did not result in pregnancy. The integration of the sFat-1 gene was confirmed in six of the seven live pups by PCR and Southern blot. The expression of the sFat-1 gene in the six transgenic pups was also detected by reverse transcription polymerase chain reaction (RT-PCR). Gas chromatography-mass spectrometry analysis revealed that transgenic rabbits exhibited an ~15-fold decrease in the ratio of n-6:n-3 PUFAs in muscle compared with wild-type rabbits and non-transgenic rabbits. These results demonstrate that sFat-1 transgenic rabbits can be produced by ICSI and display a low ratio of n-6:n-3 PUFAs.

Metabolic engineering of Pichia pastoris to produce ricinoleic acid, a hydroxy fatty acid of industrial importance.

Ricinoleic acid (12-hydroxyoctadec-cis-9-enoic acid) has many specialized uses in bioproduct industries, while castor bean is currently the only commercial source for the fatty acid. This report describes metabolic engineering of a microbial system (Pichia pastoris) to produce ricinoleic acid using a "push" (synthesis) and "pull" (assembly) strategy. CpFAH, a fatty acid hydroxylase from Claviceps purpurea, was used for synthesis of ricinoleic acid, and CpDGAT1, a diacylglycerol acyl transferase for the triacylglycerol synthesis from the same species, was used for assembly of the fatty acid. Coexpression of CpFAH and CpDGAT1 produced higher lipid contents and ricinoleic acid levels than expression of CpFAH alone. Coexpression in a mutant haploid strain defective in the Δ12 desaturase activity resulted in a higher level of ricinoleic acid than that in the diploid strain. Intriguingly, the ricinoleic acid produced was mainly distributed in the neutral lipid fractions, particularly the free fatty acid form, but with little in the polar lipids. This work demonstrates the effectiveness of the metabolic engineering strategy and excellent capacity of the microbial system for production of ricinoleic acid as an alternative to plant sources for industrial uses.

Transcriptional and antioxidative responses to endogenous polyunsaturated fatty acid accumulation in yeast.

Pathophysiology of polyunsaturated fatty acids (PUFAs) is associated with aberrant lipid and oxygen metabolism. In particular, under oxidative stress, PUFAs are prone to autocatalytic degradation via peroxidation, leading to formation of reactive aldehydes with numerous potentially harmful effects. However, the pathological and compensatory mechanisms induced by lipid peroxidation are very complex and not sufficiently understood. In our study, we have used yeast capable of endogenous PUFA synthesis in order to understand the effects triggered by PUFA accumulation on cellular physiology of a eukaryotic organism. The mechanisms induced by PUFA accumulation in S. cerevisiae expressing Hevea brasiliensis Δ12-fatty acid desaturase include down-regulation of components of electron transport chain in mitochondria as well as up-regulation of pentose-phosphate pathway and fatty acid ß-oxidation at the transcriptional level. Interestingly, while no changes were observed at the transcriptional level, activities of two important enzymatic antioxidants, catalase and glutathione-S-transferase, were altered in response to PUFA accumulation. Increased intracellular glutathione levels further suggest an endogenous oxidative stress and activation of antioxidative defense mechanisms under conditions of PUFA accumulation. Finally, our data suggest that PUFA in cell membrane causes metabolic changes which in turn lead to adaptation to endogenous oxidative stress.

Insights into the novel members of the FAD2 gene family involved in high-oleate fluxes in peanut.

The FAD2 gene family is functionally responsible for the conversion of oleic acid to linoleic acid in oilseed plants. Multiple members of the FAD gene are known to occur in several oilseed species. In this study, six novel full-length cDNA sequences (named as AhFAD2-1, -2, -3, -4, -5, and -6) were identified in peanut (Arachis hypogaea L.), an analysis of which revealed open reading frames of 379, 383, 394, or 442 amino acids. Sequence comparisons showed that AhFAD2-1 and AhFAD2-2 shared 76% identity, while AhFAD2-2, -3, and -4 displayed highly significant homology. There was only 27% identity overlap between the microsomal ω-6 fatty acid desaturase and the chloroplast ω-6 fatty acid desaturase encoded by AhFAD2-1, -2, -3, -4, and AhFAD2-5, -6, respectively. The phylogeny tree of FAD2 transcripts showed five major groups, and AhFAD2-1 was clearly separated from other groups. Analysis of AhFAD2-1 and AhFAD2-2 transcript distribution in different peanut tissues showed that the AhFAD2-1 gene showed upward of a 70-fold increase in expression of fatty acid than the AhFAD2-2 gene in peanut developing seeds, while the AhFAD2-2 gene expressed most abundantly in peanut flowers. Because the AhFAD2-1 gene played a major role in the conversion of oleic to linoleic acid during seed development, the identification of this novel member in this study would facilitate the further genetic manipulation of peanut oil quality. The implications of overall results also suggest that there may be more candidate genes controlling levels of oleate acid in developing seeds. Results also may be due to the presence of complex gene networks controlling the fluxes between the endoplasmic reticulum and the chloroplast within the peanut cells.

Diversity of Δ12 fatty acid desaturases in santalaceae and their role in production of seed oil acetylenic fatty acids.

Plants in the Santalaceae family, including the native cherry Exocarpos cupressiformis and sweet quandong Santalum acuminatum, accumulate ximenynic acid (trans-11-octadecen-9-ynoic acid) in their seed oil and conjugated polyacetylenic fatty acids in root tissue. Twelve full-length genes coding for microsomal Δ12 fatty acid desaturases (FADs) from the two Santalaceae species were identified by degenerate PCR. Phylogenetic analysis of the predicted amino acid sequences placed five Santalaceae FADs with Δ12 FADs, which include Arabidopsis thaliana FAD2. When expressed in yeast, the major activity of these genes was Δ12 desaturation of oleic acid, but unusual activities were also observed: i.e. Δ15 desaturation of linoleic acid as well as trans-Δ12 and trans-Δ11 desaturations of stearolic acid (9-octadecynoic acid). The trans-12-octadecen-9-ynoic acid product was also detected in quandong seed oil. The two other FAD groups (FADX and FADY) were present in both species; in a phylogenetic tree of microsomal FAD enzymes, FADX and FADY formed a unique clade, suggesting that are highly divergent. The FADX group enzymes had no detectable Δ12 FAD activity but instead catalyzed cis-Δ13 desaturation of stearolic acid when expressed in yeast. No products were detected for the FADY group when expressed recombinantly. Quantitative PCR analysis showed that the FADY genes were expressed in leaf rather than developing seed of the native cherry. FADs with promiscuous and unique activities have been identified in Santalaceae and explain the origin of some of the unusual lipids found in this plant family.

Metabolic engineering of Phaeodactylum tricornutum for the enhanced accumulation of omega-3 long chain polyunsaturated fatty acids.

We have engineered the diatom Phaeodactylum tricornutum to accumulate the high value omega-3 long chain polyunsaturated fatty acid docosahexaenoic acid (DHA). This was achieved by the generation of transgenic strains in which the Δ5-elongase from the picoalga Ostreococcus tauri was expressed to augment the endogenous fatty acid biosynthetic pathway. Expression of the heterologous elongase resulted in an eight-fold increase in docosahexaenoic acid content, representing a marked and valuable change in the fatty acid profile of this microalga. Importantly, DHA was shown to accumulate in triacylglycerols, with several novel triacylglycerol species being detected in the transgenic strains. In a second iteration, co-expression of an acyl-CoA-dependent Δ6-desaturase with the Δ5-elongase further increased DHA levels. Together, this demonstrates for the first time the potential of using iterative metabolic engineering to optimise omega-3 content in algae.

Glycine betaine protects tomato (Solanum lycopersicum) plants at low temperature by inducing fatty acid desaturase7 and lipoxygenase gene expression.

Cold stress is among the environmental stressors limiting productivity, yield and quality of agricultural plants. Tolerance to cold stress is associated with the increased unsaturated fatty acids ratio in the plant membranes which are also known to be substrates of octadecanoid pathway for jasmonate and other oxylipins biosynthesis. Accumulation of osmoprotectant, glycine betaine (GB) is well known to be effective in the protecting membranes and mitigating cold stress effects but, the mode of action is poorly understood. We studied the role of GB in cold stress responses of two tomato cultivated varieties; Gerry (cold stress sensitive) and T47657 (moderately cold stress tolerant) and compared the differences in lypoxygenase-13 (TomLOXF) and fatty acid desaturase 7 (FAD7) gene expression profiles and physiological parameters including relative growth rates, relative water content, osmotic potential, photosynthetic efficiency, membrane leakage, lipid peroxidation levels. Our results indicated that GB might have a role in inducing FAD7 and LOX expressions for providing protection against cold stress in tomato plants which could be related to the desaturation process of lipids leading to increased membrane stability and/or induction of other genes related to stress defense mechanisms via octadecanoid pathway or lipid peroxidation products.

Genome-wide identification and expression profiling of the fatty acid desaturase gene family in the silkworm, Bombyx mori.

Fatty acid desaturases exist in all living organisms and play important roles in many different biologic processes, such as fatty acid metabolism, lipid biosynthetic processes, and pheromone biosynthetic processes. Using the available silkworm genome sequence, we identified 14 candidate fatty acid desaturase genes. Eleven genes contain 3 conserved histidine cluster motifs and 4 transmembrane domains, but their N-terminal residues exhibit obvious diversity. Phylogenetic analysis revealed that there are 6 groups; Bmdesat1 and Bmdesat5-8 were clustered into group 2, which is involved in Δ11 desaturation activity, and Bmdesat3-4 were grouped in group 1, which is involved in Δ9 desaturation activity. Twelve of the 14 genes have expressed sequence tag evidence. Microarray data and reverse transcription polymerase chain reaction analysis demonstrated that Bmdesat3-4 and Bmdesat10 were expressed from the larval to moth stages and in multiple tissues on day 3 of 5th instar larvae. Bmdesat9, Bmdesat11, and Bmdesat14 were expressed during the pupal and late-embryonic stage, suggesting that they may take part in fatty acid metabolism to provide energy. These results provide some insights into the functions of individual fatty acid desaturases in silkworm.

[Morphophysiological and biochemical characteristics of potato plants with various expression rates of the Δ12 acyl-lipid desaturase gene].

This paper reports on morphophysiological and biochemical characteristics of control and potato plants (Solarium tuberosum L., Skoroplodnyi cultivar) transformed with the Δ12 acyl-lipid desaturase gene (desA) grown long-term in vitro. The transformed plants showed faster growth and faster ontogenesis as compared to controls, which was accompanied with changes in the accumulation of photosynthetic pigments (chlorophylls a and b, carotenoids) and phenolic compounds, including flavonoids in the leaves. These characteristics were pronounced to a high degree in Line II plants with high expression rates of the desA gene, whereas Line I plants (moderate expression rate) were similar to control plants in many parameters.

Fat-1 transgenic mice with elevated omega-3 fatty acids are protected from allergic airway responses.

Omega-3 polyunsaturated fatty acids (n-3 PUFA) have been implicated in the alleviation of asthma. Recent studies have demonstrated that the n-3 PUFA derived lipid mediators, protectin D1 and resolvin E1, may act as potent resolution agonists in airway inflammation. The effects of the n-3 PUFA tissue status itself on asthma pathogenesis remains to be further investigated. In this study allergic airway inflammation induced by allergen sensitization and aerosol challenge in Fat-1 and wild-type mice was investigated. Fat-1 transgenic mice displayed increased endogenous lung n-3 PUFA. When allergen-sensitized and aerosol-challenged, these animals had decreased airway inflammation with decreased leukocyte accumulation in bronchoalveolar lavage fluid and lung parenchyma. The Fat-1 mice had a shift to the right in the dose-response relationship for methacholine induced bronchoconstriction with a significant increase in the log ED200. The Fat-1 mice had lower BALF concentrations of the pro-inflammatory cytokines IL-1α, IL-2, IL-5, IL-9, IL-13, G-CSF, KC and RANTES. Furthermore, increased lung tissue amounts of the counter-regulatory mediators protectin D1 and resolvin E1 were found in Fat-1 mice after bronchoprovocative challenge. These results therefore demonstrate a direct protective role for lung n-3 PUFA in allergic airway responses and an increased generation of protectin D1 and resolvin E1 in this context.