Search

Ganoderic acids (GAs) are well recognized as important pharmacological components of the medicinal species belonging to the basidiomycete genus Ganoderma. However, transcription factors directly regulating the expression of GA biosynthesis genes remain poorly understood. Here, the genome of Ganoderma lingzhi is de novo sequenced. Using DNA affinity purification sequencing, we identify putative targets of the transcription factor sterol regulatory element-binding protein (SREBP), including the genes of triterpenoid synthesis and lipid metabolism. Interactions between SREBP and the targets are verified by electrophoretic mobility gel shift assay. RNA-seq shows that SREBP targets, mevalonate kinase and 3-hydroxy-3-methylglutaryl coenzyme A synthetase in mevalonate pathway, sterol isomerase and lanosterol 14-demethylase in ergosterol biosynthesis, are significantly upregulated in the SREBP overexpression (OE::SREBP) strain. In addition, 3 targets involved in glycerophospholipid/glycerolipid metabolism are upregulated. Then, the contents of mevalonic acid, lanosterol, ergosterol and 13 different GAs as well as a variety of lipids are significantly increased in this strain. Furthermore, the effects of SREBP overexpression on triterpenoid and lipid metabolisms are recovered when OE::SREBP strain are treated with exogenous fatostatin, a specific inhibitor of SREBP. Taken together, our genome-wide study clarify the role of SREBP in triterpenoid and lipid metabolisms of G. lingzhi. An integration of genomic, DAP-seq, RNA-seq, metabolomic and genetic approaches identifies SREBP as a key transcription factor regulating triterpenoid and lipid metabolisms in the medicinal fungus Ganoderma lingzhi. [ABSTRACT FROM AUTHOR]

Cordyceps militaris is a famous traditional edible and medicinal fungus in Asia, and its fruiting body has rich medicinal value. The molecular mechanism of fruiting body development is still not well understood in C. militaris. In this study, phylogenetically analysis and protein domains prediction of the 14 putative chitinases were performed. The transcription level and enzyme activity of chitinase were significant increased during fruiting body development of C. militaris. Then, two chitinase genes (Chi1 and Chi4) were selected to construct gene silencing strain by RNA interference. When Chi1 and Chi4 genes were knockdown, the differentiation of the primordium was blocked, and the number of fruiting body was significantly decreased approximately by 50% compared to wild-type (WT) strain. The length of the single mature fruiting body was shortened by 27% and 38% in Chi1- and Chi4-silenced strains, respectively. In addition, the chitin content and cell wall thickness were significantly increased in Chi1- and Chi4-silenced strains. These results provide new insights into the biological functions of chitinase in fruiting body development of C. militaris. [ABSTRACT FROM AUTHOR]

In this paper, a thin-walled-microsphere air-cavity (TWMAC) F-P interferometric fiber temperature sensor is proposed for high-temperature measurement up to 400 °C. The TWMAC sensing structure, which is fabricated by discharging the structure of single-mode fiber splicing with hollow-core fiber to form an air-cavity with a three-beam interference. Its interferometric operation, temperature sensing principle, and sensitization by vernier effect were analyzed theoretically and fundamentally. The sensor is fabricated by a splice machine, packaged by a copper tube and tested in the temperature range of 50–400 °C. The TWMAC has a sensitivity of roughly 3 pm/°C, while the vernier effect can increase the sensitivity up to − 18.92 pm/°C, which is 5-times more sensitive. The proposed sensor can be utilized for high temperature measurements in environments with complicated production or life processes because it is lightweight, compact, and anti-electromagnetic interference. [Display omitted] • A thin-walled-microsphere air-cavity (TWMAC) fiber sensing structure for temperature was presented. • It could achieve a high-temperature sensitivity up to − 18.92 pm/℃ by Vernier effect under the temperature up to 400 ℃. • Its sensitivity was 5 times than that of a traditional fiber F-P sensor. [ABSTRACT FROM AUTHOR]