α-酮戊二酸及其钠盐对雨生红球藻生长和虾青素积累的促进作用

雨生红球藻是已知虾青素(astaxanthin,AST)含量最高的生物,是理想的细胞制备工厂。尽管研究表明添加α-酮戊二酸(OG,α-oxoglutarate)能有效促进混养条件下雨生红球藻AST积累,但在自养条件下是否也有类似效果不清楚。研究以自养雨生红球藻为对象,在正常(CK)、高光(HL)、缺氮(DN)和高光-缺氮双重逆境(HL-DN)下从细胞生长和AST积累两方面评估OG及其钠盐(OG-2Na)的促进作用。结果显示,添加OG或OG-2Na显著缓解HL、DN和HL-DN胁迫对细胞生长的抑制作用,培养至6d的生物量分别为0.58、0.53和0.38g/L,约是未添加组的2.0倍。添加OG或OG-2Na显著促进AST积累。培养至6d,在HL、DN和HL-DN下,AST含量分别达到13.62、19.51和28.29mg/g,是未添加组的2.39、1.16和1.35倍。同时在胁迫条件下,添加OG或OG-2Na有效提高单位细胞中AST含量。针对OG和OG-2Na添加,最大单位细胞AST含量分别出现在HL和HL-DN条件下,达到53.72和60.58pg/cell,是对照的3.09和2.83倍。在CK下,添加10.0mg/L的OG或OG-2Na,其AST含量显著高于单独的胁迫条件。上述结果证实OG或OG-2Na不但可减少HL、DN和HL-DN胁迫对红球藻细胞生长的抑制、显著提高其AST含量,是一种在提高AST产量的有效途径

Phenotypic Characterization of Blue Photoreceptor Plant Type Cryptochrome CRY Mutant in Chlamydomonas reinhardtii

The phenotypic differences of Chlamydomonas reinhardtii wild strain(CC5325)and CRY mutant strain(crcry)under normal CK(Control)and Blue BL(Blue light)cultures were investigated. The PCR verification showed that the crcry mutant was inserted with paromomycin resistance gene AphVIII expression box in the coding region. AphVIII resistance gene was inserted into crcry mutant and successfully expressed in plate and liquid culture system with paromomycin as screening condition. Phenotypic identification showed that there were no significant differences in growth, pigment, photosynthesis and lipid synthesis between wild strain CC5325 and mutant strain crcry under CK culture condition. However, under BL condition, the growth of mutant crcry was significantly inhibited, and the color of algae liquid turned yellow. Chlorophyll a, chlorophyll b and total pigment contents of unit cells decreased significantly, while total carotenoid contents increased significantly. The photosynthetic system was severely suppressed and the total lipid content significantly reduced. In conclusion, plant cry is involved in the blue light response of C. reinhardtii

Identification of blue light receptor phototropin (PHOT) interacting protein from Haematococcus pluvialis and physiological effect of its heterologous expression in tobacco

Photropin (PHOT) is a unique blue light receptor in plants and green algae.Identification of PHOT interacting proteins and their functions will lay a foundation for elucidating PHOT-mediated signaling pathways and physiological functions.In this study,the yeast two-hybridization (Y2H) was used to screen the candidate interacting proteins of HaePHOT from the cDNA library of Haematococcus pluvialis.A total of 23 positive clones were obtained,of which four clones were annotated as DnaJ.The expression correlation of HaePHOT and DnaJ in H.pluvialis showed a strong positive model basing on RNA-Seq data.Further analysis of the expression correlation between HaePHOT or DnaJ and astaxanthin synthetic genes showed that HaePHOT and DnaJ were positively correlated with LYCB,BKT,BCH and CYP97B,but negatively correlated with PSY,PDS,KAS and FAD,respectively.Transient expression assay in tobacco showed that there was no significant difference in chlorophyll a,chlorophyll b and carotenoids contents between wildtype tobacco and HaePHOT-overexpressing tobacco under normal light (white light).However,under blue light,the contents of those pigments were higher in the transient-expression plants than that in the wildtype tobacco.qRT-PCR analysis showed that the expression of genes encoding chlorophyll a oxygenase(CAO),protochlorophyllide oxidoreductase (POR),phytoene synthase (PSY),phytoene desaturase (PDS) and lycopene beta-cyclase (LYCB) were significantly increased under blue light irradiation in the transient-expression tobacco plants,which was consistent with the change pattern of chlorophylls and carotenoids contents.These findings provide a theoretical basis for further revealing the regulatory mechanisms mediated by HaePHOT and its interacting proteins

α-酮戊二酸及其钠盐对雨生红球藻生长和虾青素积累的促进作用

雨生红球藻是已知虾青素(astaxanthin,AST)含量最高的生物,是理想的细胞制备工厂。尽管研究表明添加α-酮戊二酸(OG,α-oxoglutarate)能有效促进混养条件下雨生红球藻AST积累,但在自养条件下是否也有类似效果不清楚。研究以自养雨生红球藻为对象,在正常(CK)、高光(HL)、缺氮(DN)和高光-缺氮双重逆境(HL-DN)下从细胞生长和AST积累两方面评估OG及其钠盐(OG-2Na)的促进作用。结果显示,添加OG或OG-2Na显著缓解HL、DN和HL-DN胁迫对细胞生长的抑制作用,培养至6d的生物量分别为0.58、0.53和0.38g/L,约是未添加组的2.0倍。添加OG或OG-2Na显著促进AST积累。培养至6d,在HL、DN和HL-DN下,AST含量分别达到13.62、19.51和28.29mg/g,是未添加组的2.39、1.16和1.35倍。同时在胁迫条件下,添加OG或OG-2Na有效提高单位细胞中AST含量。针对OG和OG-2Na添加,最大单位细胞AST含量分别出现在HL和HL-DN条件下,达到53.72和60.58pg/cell,是对照的3.09和2.83倍。在CK下,添加10.0mg/L的OG或OG-2Na,其AST含量显著高于单独的胁迫条件。上述结果证实OG或OG-2Na不但可减少HL、DN和HL-DN胁迫对红球藻细胞生长的抑制、显著提高其AST含量,是一种在提高AST产量的有效途径

JUNO Sensitivity on Proton Decay p→νˉK+p\to \bar\nu K^+ Searches

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this paper, the potential on searching for proton decay in $p\to \bar\nu K^+$ mode with JUNO is investigated.The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits to suppress the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar\nu K^+$ is 36.9% with a background level of 0.2 events after 10 years of data taking. The estimated sensitivity based on 200 kton-years exposure is $9.6 \times 10^{33}$ years, competitive with the current best limits on the proton lifetime in this channel

JUNO sensitivity on proton decay p → ν K + searches*

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this study, the potential of searching for proton decay in the $p\to \bar{\nu} K^+$ mode with JUNO is investigated. The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits suppression of the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar{\nu} K^+$ is 36.9% ± 4.9% with a background level of $0.2\pm 0.05({\rm syst})\pm$$0.2({\rm stat})$ events after 10 years of data collection. The estimated sensitivity based on 200 kton-years of exposure is $9.6 \times 10^{33}$ years, which is competitive with the current best limits on the proton lifetime in this channel and complements the use of different detection technologies