Ethylene regulates mycelial growth, primordium formation, and postharvest mushroom maturation and senescence in the white button mushroom, Agaricus bisporus. However, it remains unknown how ethylene ...is detected by the mushroom. In this study, we found that two hybrid histidine kinases in the mushroom, designated
ETR1 and
ETR2, showed domain structures similar to those of plant ethylene receptors. The transmembrane helices of
ETR1 and
ETR2 were expressed in yeast cells and showed ethylene-binding activities. Mushroom strains with downregulated expressions of
ETR1 and
ETR2 showed reduced sensitivity to the ethylene inhibition of mycelial growth, ethylene regulation of their own synthesis, postharvest mushroom maturation, and senescence and expression of maturation- and senescence-related genes. Therefore,
ETR1 and
ETR2 are expected to be biologically functional ethylene receptors and exhibit a different mode of action from that of the receptors of plants. Here, we fill gaps in the knowledge pertaining to higher fungus ethylene receptors, discover a novel mode of action of ethylene receptors, confirm ethylene as a novel fungal hormone, and provide a facilitated approach for preventing the maturation and senescence of postharvest button mushrooms.
Ethylene regulates diverse physiological activities in bacteria, cyanobacteria, fungi, and plants, but how to perceive ethylene by fungi only remains unknown. In this study, we identify two biologically functional ethylene receptors in the basidiomycete fungus Agaricus bisporus, which fills the gaps of deficient fungal ethylene receptors. Furthermore, we found that decreased expression of the ethylene receptors facilitates preventing the maturation and senescence of postharvest button mushrooms, indicating that the two fungal ethylene receptors positively regulate the ethylene response, in contrast to that in plants.
1-aminocyclopropane-1-carboxylic acid (ACC) is a strong metabolism-dependent chemoattractant for the plant beneficial rhizobacterium
sp. UW4. It is unknown whether enhancing the metabolic rate of ACC ...can intensify the chemotaxis activity towards ACC and rhizocompetence. In this study, we selected four promoters to transcribe the UW4 ACC deaminase (AcdS) gene in the UW4 Δ
mutant. PA is the UW4
gene promoter, PB20, PB10 and PB1 are synthetic promoters. The order of the
gene expression level and AcdS activity of the four strains harboring the promoters were PB20 > PA > PB10 > PB1. Interestingly, the AcdS activity of the four strains and their parent strain UW4 was significantly positively correlated with their chemotactic activity towards ACC, rhizosphere colonization, roots elongation and dry weight promotion. The results released that enhancing the AcdS activity of PGPRenable them to achieve strong chemotactic responses to ACC, rhizocompetence and plant growth promotion.
The 11α-hydroxylation of 16α, 17-epoxyprogesterone (EP) catalyzed by Rhizopus nigricans is crucial for the steroid industry. However, lower conversion rate of the biohydroxylation restricts its ...potential industrial application. The 11α-steroid hydroxylase CYP509C12 from R. oryzae were reported to play a crucial role in the 11α-hydroxylation in recombinant fission yeast. In the present study, the CYP509C12 of R. oryzae (RoCYP) was introduced into R. nigricans using the liposome-mediated mycelial transformation. Heterologous expression of RoCYP resulted in increased fungal growth and improved intracellular reactive oxygen species content in R. nigricans. The H
2
O
2
levels in RoCYP transformants were approximately 2-folder that of the R. nigricans wild type (RnWT) strain, with the superoxide dismutase activities increased approximately 45% and catalase activities decreased approximately 68%. Furthermore, the 11α-hydroxylation rates of EP in RoCYP transformants (C4, C6 and C9) were 39.7%, 38.3% and 38.7%, which were 12.1%, 8.2% and 9.4% higher than the rate of the RnWT strain, respectively. This paper investigated the effect of heterologous expression of RoCYP in R. nigricans, providing an effective genetic method to construct the engineered strains for steroid industry.
The 11a-hydroxylation of 16a, 17-epoxyprogesterone (EP) catalyzed by Rhizopus nigricans is crucial for the steroid industry. However, lower conversion rate of the biohydroxylation restricts its ...potential industrial application. The 11a-steroid hydroxylase CYP509C12 from R. oryzae were reported to play a crucial role in the 11a-hydroxylation in recombinant fission yeast. In the present study, the CYP509C12 of R. oryzae (RoCYP) was introduced into R. nigricans using the liposome-mediated mycelial transformation. Heterologous expression of RoCYP resulted in increased fungal growth and improved intracellular reactive oxygen species content in R. nigricans. The H 2 O 2 levels in RoCYP transformants were approximately 2-folder that of the R. nigricans wild type (RnWT) strain, with the superoxide dismutase activities increased approximately 45% and catalase activities decreased approximately 68%. Furthermore, the 11a-hydroxylation rates of EP in RoCYP transformants (C4, C6 and C9) were 39.7%, 38.3% and 38.7%, which were 12.1%, 8.2% and 9.4% higher than the rate of the RnWT strain, respectively. This paper investigated the effect of heterologous expression of RoCYP in R. nigricans, providing an effective genetic method to construct the engineered strains for steroid industry.
To detect T cell immunoglobulin and mucin domain-containing molecule 3(Tim-3) expression on peripheral blood monocyts (PBMs) and explore its effect on inflammatory cytokines production of PBMs in ...patients with chronic hepatitis B (CHB).
The expression of Tim-3 protein and mRNA on PBM subsets was respectively determined using flow cytometry and real-time quantitative RT-PCR (qRT-PCR) in CHB patients at different phases. After PBMs were stimulated with both recombinant human galectin-9 and lipopolysaccharide (LPS) in active CHB patients, the supernatants were collected to measure the levels of proinflammatory factors including TNF-α, IL-1β and IL-6 by ELISA.
Compared with healthy controls and CHB patients at immune active (IA) phase, the expression of Tim-3 was significantly up-regulated in PBMs of CHB patients at immune tolerance (IT) phase (P<0.01). The level of Tim-3 expression on both CD14(+);CD16-; and CD14(+);CD16(+); monocyte subsets of CHB patients at IT phase was significantly higher than that of the C
•VHb expression promoted shiitake mycelial growth under hypoxic condition.•VHb expression promoted laccase and amylase production of the shiitake mycelia.•VHb expression enhanced β-glucan synthesis ...in shiitake mycelia.
Vitreoscilla hemoglobin (VHb), encoded by the Vitreoscilla hemoglobin gene (vgb), is highly effective at binding oxygen and delivering it to both prokaryotes and eukaryotes under hypoxic conditions. In this study, we introduced the vgb gene into shiitake mushrooms, and the mycelia of the transformatants grew faster. In particular, they spread into the solid substrate located in the lower part of the test tubes and bags where the oxygen was hypoxic and produced more β-glucan and plant biomass degrading enzymes compared to the original strain. The maximum growth rate of the transformants was 8.5%–15.9% higher than that of the original strain on sawdust-based cultures in plastic bags. The laccase and amylase activities were 17.7%–40.3% and 16.7%–37.9% higher than that of the original strain, respectively. In addition, the β-glucan contents of the transformant mycelia from the submerged fermentation were 12.9%–24.0% higher than that of the original strain. These results reveal that the expression of VHb in mushroom fungi promots the mycelial growth in solid-state cultures under the hypoxic condition as well as enhances β-glucan and plant biomass degrading enzymes production.
The 11a-hydroxylation of 16a, 17-epoxyprogesterone (EP) catalyzed by Rhizopus nigricans is crucial for the steroid industry. However, lower conversion rate of the biohydroxylation restricts its ...potential industrial application. The 11a-steroid hydroxylase CYP509C12 from R.
oryzae were reported to play a crucial role in the 11a-hydroxylation in recombinant fission yeast. In the present study, the CYP509C12 of R. oryzae (RoCYP) was introduced into R. nigricans using the liposome-mediated mycelial transformation. Heterologous expression of RoCYP resulted in increased fungal growth and improved intracellular reactive oxygen species content in R. nigricans. The H2O2 levels in RoCYP transformants were approximately 2-folder that of the R. nigricans wild type (RnWT) strain, with the superoxide dismutase activities increased approximately 45% and catalase activities decreased approximately 68%.
Furthermore, the 11a-hydroxylation rates of EP in RoCYP transformants (C4, C6 and C9) were 39.7%, 38.3% and 38.7%, which were 12.1%, 8.2% and 9.4% higher than the rate of the RnWT strain, respectively. This paper investigated the effect of heterologous expression of RoCYP in R. nigricans, providing an effective genetic method to construct the engineered strains for steroid industry. KCI Citation Count: 2
Dysfunction of dendritic cells (DCs) is considered one of the factors for chronic hepatitis B virus (HBV) infection. However the reason for impairment of DCs remains elusive. The aim of this study ...was to investigate the effect of telbivudine on number and function of DCs in patients with chronic hepatitis B (CHB). After 6 months of telbivudine treatment, the number of plasmacytoid DCs (pDCs) increased significantly, nearly to levels observed in normal controls. However the capacity of pDCs to produce interferon α (IFN-α) was not enhanced during treatment. Accordingly, monocyte-derived DCs (MoDCs) exhibited a markedly enhanced expression of HLA-DR, decreased expression of PD-L1, and increased capacity to produce interleukin (IL)-12. These findings suggest that the improved function of peripheral myeloid DCs (mDCs) with telbivudine therapy in CHB patients may be associated with up-regulated expression of HLA-DR and down-regulated expression of PD-L1.
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