Search

Auricularia auricula-judae is an edible nutrient-rich mushroom, which is a traditional medicinal resource in China. It is known that environment stimuli will affect the production of melanin by A. auricula-judae , but the mechanism of the effects of freezing treatment on melanin accumulation remains unknown. In the present study, the synthesis of melanin in A. auricula-judae was analyzed by physiological assays and a proteomics approach. Our findings showed that a longer freezing treatment causes a lighter color of A. auricula-judae fruiting bodies. The proteomic analysis showed that proteins involved in glycolysis/gluconeogenesis, tyrosine metabolism, ribosome, and arginine biosynthesis might contribute to the color differences in the A. auricula-judae after freezing treatment. This work will be expected to provide valuable information on the physiological and molecular mechanisms of freezing treatment on the color quality of A. auricula-judae. [ABSTRACT FROM AUTHOR]

Auricularia auricula is one of the most popular edible mushrooms in China. Limited information is available regarding genes and proteins related to A. auricula development from mycelium to mature fruiting body and response to environmental stimuli. With the development of proteomics, this technology platform for addressing this problem is available. A critical step of a good proteome is protein extraction which can gives the best quality and a wide coverage of total proteins. To establish an effective protein extraction protocol suitable for proteomics analysis in mycelium and fruiting body of A. auricula, four previously reported protein extraction protocols including direct extraction, trichloroacetic acid (TCA) precipitation, TCA/acetone precipitation and phenol-based extraction, were compared based on the protein yield and 2-DE patterns. The efficiency of the four methods was evaluated by comparing protein yield and 2-DE patterns. Of the four methods, both TCA precipitation and phenol-based extraction method for A. auricula mycelia protein extraction yielded the good protein separation pattern and higher number of protein spots in 2-DE analysis. Furthermore, phenol-based extraction is superior to the other tested methods for A. auricula fruiting body proteome analysis. [ABSTRACT FROM AUTHOR]

• Cotyledons and roots of castor have different adaptive mechanisms under alkali stress. • Roots could sequester a large amount of Na+, so that cotyledons can maintain physiological functions such as photosynthesis. • Cotyledons retain efficiency of photosynthetic electron transport and accumulation of osmolytes. • Roots enhance the transfer efficiency of the mitochondrial electron transport chain and promote PA biosynthesis Soil alkalinity is a major environmental problem influencing plant growth and productivity in northeastern China. Castor plant (Ricinus communis) is one of the most important oilseed crops worldwide, and has good salt tolerance. The early seedling stage is extremely vulnerable to abiotic stresses, but little is known about the physiological and molecular mechanisms involved in the cotyledons and roots of castor seedlings under alkali stress. In this study, biomass, photosynthesis, root vitality, inorganic ions, organic solutes and antioxidant enzyme activities were measured. Two-dimensional gel electrophoresis-based proteomic approaches were also applied to identify differentially abundant proteins in alkali-treated seedlings. The results showed that alkali stress strongly inhibited seedling growth, especially of the roots. Na+ content increased with increasing alkalinity, and the roots had much higher Na+ and lower K+ than cotyledons. The proline and soluble sugars were both increased in cotyledons, but kept unchanged in the roots under alkali stress. Moreover, proteomic analysis revealed a total of 15 and 25 alkali-responsive proteins in the cotyledons and roots, respectively. For cotyledons, most of the identified proteins were involved in photosynthesis, stress and defense (＞10 %), while those for roots were mainly involved in carbohydrate and energy metabolism, genetic information, stress and defense (＞10 %). These results suggest that cotyledons and roots respond differently to alkali stress. Cotyledons retain efficiency of photosynthetic electron transport and accumulation of osmolytes, while the roots enhance transfer efficiency of the mitochondrial electron transport chain, adjust fatty acid biosynthesis, and promote phosphatidic acid biosynthesis under alkali stress. Additionally, the co-increased abundance of chaperonins indicated that both cotyledons and roots maintained folding of proteins into their proper 3D structures in response to alkali stress. These findings provide new insights into different physiological mechanisms in cotyledon and root responses to alkali stress during the early seedling stage in castor. [ABSTRACT FROM AUTHOR]

Background: ω-3 polyunsaturated fatty acids (PUFAs) are synthesized from α-Linolenic acid (ALA, C18:3ω3) and play important roles in anti-inflammatory and antioxidant responses in mammal cells. ALA is an essential fatty acid which cannot be produced within the human body and must be acquired through diet. The purpose of this study was to evaluate the potential of a novel microalgal strain (HDMA-20) as a source of ω-3 PUFAs including ALA and eicosatetraenoic acid (ETA, C20:4ω3)., Method: Phylogenetic Neighbor-Joining analysis based on 18S ribosomal DNA sequence was used to identify the microalga strain HDMA-20. Autotrophic condition was chosen to cultivate HDMA-20 to reduce the cultivation cost. GC-MS was used to determine the fatty acid composition of HDMA-20 lipid., Results: A microalgal strain (HDMA-20) from Lake Chengfeng (Daqing, Heilongjiang province, China) was found to accumulate high content of ω-3 PUFAs (63.4% of total lipid), with ALA and eicosatetraenoic acid (ETA, C20:4ω3) accounting for 35.4 and 9.6% of total lipid, respectively. Phylogenetic analysis based on 18S ribosomal DNA sequences suggested that the HDMA-20 belonged to genus Monoraphidium (Selenastraceae, Sphaeropleales) and its 18S rDNA sequence information turned out to be new molecular record of Monoraphidium species. The biomass productivity and lipid content of HDMA-20 were also investigated under autotrophic condition. The biomass productivity of HDMA-20 reached 36.3 mg L - 1  day - 1 , and the lipid contents was 22.6% of dry weight., Conclusion: HDMA-20 not only represent an additional source of ALA, but also a totally new source of ETA. The high content of ω-3 PUFAs, especially ALA, of HDMA-20, makes it suitable as a source of nutrition supplements for human health. In addition, HDMA-20 exhibited good properties in growth and lipid accumulation, implying its potential for cost-effective ω-3 PUFAs production in future.