Plants have evolved complex signaling pathways to coordinate responses to developmental and environmental Information. The oxylipin pathway Is one pivotal lipid-based signaling network, composed of several competing b...Plants have evolved complex signaling pathways to coordinate responses to developmental and environmental Information. The oxylipin pathway Is one pivotal lipid-based signaling network, composed of several competing branch pathways, that determines the plant＇s ability to adapt to various stimuli. Activation of the oxyllpln pathway Induces the de novo synthesis of biologically active metabolltes called ＂oxyllplns＂. The relative levels of these metabolltes are a distinct indicator of each plant species and determine the ability of plants to adapt to different stimuli. The two major branches of the oxyllpln pathway, allene oxide synthase （AOS） and hydroperoxlde lyase （HPL） are responsible for production of the signaling compounds, jasmonates and aldehydes respectively. Here, we compare and contrast the regulation of AOS and HPL branch pathways In rice and Arabidopsis as model monocotyledonous and dicotyledonous systems. These analyses provide new Insights Into the evolution of JAs and aldehydes signaling pathways, and the complex network of processes responsible for stress adaptations In monocots and dicots.展开更多
In this study, the activities of phenylalanine ammonia lyase （PAL）, polyphenoloxidase （PPO）, and peroxidase （POD） were assayed in cucumber seedlings （Cucumis sativus L.） at 0, 6, 12, 24, 48, 72, and 96 h after...In this study, the activities of phenylalanine ammonia lyase （PAL）, polyphenoloxidase （PPO）, and peroxidase （POD） were assayed in cucumber seedlings （Cucumis sativus L.） at 0, 6, 12, 24, 48, 72, and 96 h after they were infested by Bemisia tabaci （Gennadius） using spectrophotometric analysis. The results indicated that herbivore infestation increased the activities of PAL, PPO, and POD. The enzymes showed different activity levels at different times after the infestation. The PAL activity reached the first high peak by 23.1% at 6 h and the highest peak by 29.1% at 48 h compared to the control. The PPO activity reached the first high peak by 22.7% at 6 h and the highest peak by 52.6% at 24 h, and the POD activity reached the highest peak by 213.2% at 6 h and another higher peak value by 135.2% at 96 h. The results suggest that the enhanced activities of the enzymes may contribute to bioprotection of cucumber plants against B. tabaci infestation.展开更多
AIM: To investigate the association between endogenous hydrogen sulfide (H<sub>2</sub>S) and portal hypertension as well as its effect on vascular smooth muscle cells.
Background: Hepatocellular carcinoma(HCC) is one of the most highly malignant tumors. Liver tumor-initiating cells(LTICs) have been considered to contribute to HCC progression and metastasis. ATP-citrate lyase(ACLY), ...Background: Hepatocellular carcinoma(HCC) is one of the most highly malignant tumors. Liver tumor-initiating cells(LTICs) have been considered to contribute to HCC progression and metastasis. ATP-citrate lyase(ACLY), as a key enzyme for de novo lipogenesis, has been reported to be upregulated in various tumors. However, its expression and role in HCC and LTICs remain unknown. Methods: The expressions of ACLY in HCC tissues were detected by quantitative real-time PCR(q RT-PCR), Western blotting and immunohistochemistry. Kaplan-Meier curves and Chi-square test were used to determine the clinical significance of ACLY expression in HCC patients. A series of assays were performed to determine the function of ACLY on stemness, migration and invasion of HCC cells. Luciferase reporter assay, Western blotting and immunoprecipitation were used to study the regulation of the Wnt/β-catenin signaling by ACLY. Rescue experiments were performed to investigate whether β-catenin was the mediator of ACLY-regulated stemness and migration in HCC cells. Results: ACLY was highly expressed in HCC tissues and LTICs. Overexpression of ACLY was significantly correlated with poor prognosis, progression and metastasis of HCC patients. Knockdown of ACLY remarkably suppressed stemness properties, migration and invasion in HCC cells. Mechanistically, ACLY could regulate the canonical Wnt pathway by affecting the stability of β-catenin, and Lys49 acetylation of β-catenin might mediate ACLY-regulated β-catenin level in HCC cells. Conclusions: ACLY is a potent regulator of Wnt/β-catenin signaling in modulating LTICs stemness and metastasis in HCC. ACLY may serve as a new target for the diagnosis and treatment of HCC.展开更多
Sphingolipids, including sphingosine-l-phosphate （SIP）, have been shown to function as signaling mediators to regulate diverse aspects of plant growth, development, and stress response. In this study, we performed f...Sphingolipids, including sphingosine-l-phosphate （SIP）, have been shown to function as signaling mediators to regulate diverse aspects of plant growth, development, and stress response. In this study, we performed functional analysis of a rice （Oryza sativa） SlP lyase gene OsSPL1 in transgenic tobacco plants and explored its possible involvement in abiotic stress response. Overexpression of OsSPL1 in transgenic tobacco resulted in enhanced sensitivity to exogenous abscisic acid （ABA）, and decreased tolerance to salt and oxidative stress, when compared with the wild type. Furthermore, the expression levels of some selected stress-related genes in OsSPLl-overexpressing plants were reduced after application of salt or oxidative stress, indicating that the altered responsiveness of stress-related genes may be responsible for the reduced tolerance in OsSPLl.overexpressing tobacco plants under salt and oxidative stress. Our results suggest that rice OsSPL1 plays an important role in abiotic stress responses.展开更多
This review is concerned with the mechanisms controlling fruit softening.Master genetic regulators switch on the ripening programme and the regulatory pathway branches downstream,with separate controls for distinct qu...This review is concerned with the mechanisms controlling fruit softening.Master genetic regulators switch on the ripening programme and the regulatory pathway branches downstream,with separate controls for distinct quality attributes such as colour,flavour,texture,and aroma.Ethylene plays a critical role as a ripening hormone and is implicated in controlling different facets of ripening,including texture change,acting through a range of transcriptional regulators,and this signalling can be blocked using 1-methylcyclopropene.A battery of at least seven cell-wall-modifying enzymes,most of which are synthesized de novo during ripening,cause major alterations in the structure and composition of the cell wall components and contribute to the softening process.Significant differences between fruits may be related to the precise structure and composition of their cell walls and the enzymes recruited to the ripening programme during evolution.Attempts to slow texture change and reduce fruit spoilage by delaying the entire ripening process can often affect negatively other aspects of quality,and low temperatures,in particular,can have deleterious effects on texture change.Gene silencing has been used to probe the function of individual genes involved in different aspects of ripening,including colour,flavour,ethylene synthesis,and particularly texture change.The picture that emerges is that softening is a multi-genic trait,with some genes making a more important contribution than others.In future,it may be possible to control texture genetically to produce fruits more suitable for our needs.展开更多
PECTATE LYASE‐LIKE10（PLL10） was previously identified as one of the differentially expressed genes both in microspores during the late pollen developmental stages and in pistils during the fertilization process in ...PECTATE LYASE‐LIKE10（PLL10） was previously identified as one of the differentially expressed genes both in microspores during the late pollen developmental stages and in pistils during the fertilization process in Chinese cabbage（Brassica campestris ssp. chinensis）. Here, antisense‐RNA was used to study the functions of BcPLL10 in Chinese cabbage. Abnormal pollen was identified in the transgenic lines（bcpll10‐4, ‐5, and ‐6）. In fertilization experiments, fewer seeds were harvested when the antisense‐RNA lines were used as pollen donor. In vivo and in vitro pollen germination assays less germinated pollen tubes were observed in bcpll10 lines. Scanning electron microscopy observation verified that the tryphine materials were over accumulated around the pollen surface and sticked them together in bcpll10.Moreover, transmission electron microscopy observation revealed that the internal endintine was overdeveloped and predominantly occupied the intine, and disturbed thenormal proportional distribution of the two layers in the non‐germinal furrow region; and no obvious demarcation existed between them in the germinal furrow region in the bcpll10 pollen. Collectively, this study presented a novel PLL gene that played an important role during the pollen wall development in B. campestris, which may also possess potential importance for male sterility usage in agriculture.展开更多
Background Sphingosine-1-phosphate lyase insufficiency syndrome(SPLIS)or nephrotic syndrome type-14 is caused by biallelic mutations in SGPL1.Here,we conducted a systematic review to delineate the characteristics of S...Background Sphingosine-1-phosphate lyase insufficiency syndrome(SPLIS)or nephrotic syndrome type-14 is caused by biallelic mutations in SGPL1.Here,we conducted a systematic review to delineate the characteristics of SPLIS patients.Methods A literature search was performed in PubMed,Web of Science,and Scopus databases,and eligible studies were included.For all patients,demographic,clinical,laboratory,and molecular data were collected and analyzed.Results Fifty-five SPLIS patients(54.9%male,45.1%female)were identified in 19 articles.Parental consanguinity and positive family history were reported in 70.9%and 52.7%of patients,respectively.Most patients(54.9%)primarily manifested within the first year of life,nearly half of whom survived,while all patients with a prenatal diagnosis of SPLIS(27.5%)died at a median[interquartile(IQR)]age of 2(1.4–5.3)months(P=0.003).The most prevalent clinical feature was endocrinopathies,including primary adrenal insufficiency(PAI)(71.2%)and hypothyroidism(32.7%).Kidney disorders(42,80.8%)were mainly in the form of steroid-resistant nephrotic syndrome(SRNS)and progressed to end-stage kidney disease(ESKD)in 19(36.5%)patients at a median(IQR)age of 6(1.4–42.6)months.Among 30 different mutations in SGPL1,the most common was c.665G>A(p.Arg222Gln)in 11(20%)patients.Twenty-six(49.1%)patients with available outcome were deceased at a median(IQR)age of 5(1.5–30.5)months,mostly following ESKD(23%)or sepsis/septic shock(23%).Conclusion In patients with PAI and/or SRNS,SGPL1 should be added to diagnostic genetic panels,which can provide an earlier diagnosis of SPLIS and prevention of ESKD and other life-threatening complications.展开更多
Carbohydrases secreted by marine Vibrio sp. YKW-34 with strong Laminaria cell wall degrading ability were screened, and among them alginate lyase was found to be dominant. The effects of medium composition and culturi...Carbohydrases secreted by marine Vibrio sp. YKW-34 with strong Laminaria cell wall degrading ability were screened, and among them alginate lyase was found to be dominant. The effects of medium composition and culturing condition on the produc- tion of alginate lyase by marine Vibrio sp. YKW-34 in flask were investigated in this study. In the culture medium of marine broth, no alginate lyase was produced. The activity of the alginate lyase, after being induced, reached 5 UmL–1. The best inoculum volume and inoculum age were 10% and 12 h, respectively. The optimal temperature for alginate lyase production was 25℃. The fermentation medium was composed of 0.5% of Laminaria powder and 0.2% of KNO3 with an initial acidity of pH 8.0. Alginate could induce alginate lyase production but not as efficiently as Laminaria powder did. The addition of fucoidan, cellulose and glucose had nega- tive effect on the alginate lyase production. Other kinds of nitrogen sources, such as yeast extract, beef extract and peptone, had posi- tive effect on the growth of the microorganism and negative effect on alginate lyase production. In addition, the time course of algi- nate lyase production under the optimized condition was described. The optimal harvest time was 48 h.展开更多
Salicylic acid(SA),a vital endogenous hormone,plays a crucial role in plant growth and the response to abiotic and biotic stress.Isochorismate synthase(ICS)and phenylalanine ammonia lyase(PAL)are critical rate-limitin...Salicylic acid(SA),a vital endogenous hormone,plays a crucial role in plant growth and the response to abiotic and biotic stress.Isochorismate synthase(ICS)and phenylalanine ammonia lyase(PAL)are critical rate-limiting enzymes for SA synthesis.Fusarium head blight(FHB)seriously threatens the safety of wheat production,but increasing the content of SA can enhance FHB resistance.However,the pathway of SA synthesis and regulation in wheat remains unknown.In this study,three wheat ICS(TaICSA,TaICSB,and TaICSD)were identified,and their functions were validated in vitro for isomerizing chorismate to isochorismate.The mutation of one or two homoeoalleles of TaICSA,TaICSB,and TaICSD in the wheat variety‘Cadenza’reduced SA levels under ultraviolet treatment and Fusarium graminearum infection,further enhancing sensitivity to FHB.Overexpression of TaICSA can significantly enhance SA levels and resistance to FHB.To further study SA synthesis pathways in wheat and avoid interference with pathogenicity related genes,the leaves of wild-type Cadenza and different TaICS mutant lines were subjected to ultraviolet treatment for transcriptomic analysis.The results showed that 37 PALs might be involved in endogenous SA synthesis,and 82 WRKY and MYB family transcription factors may regulate the expression of ICS and PAL.These results were further confirmed by RT-PCR.In conclusion,this study expands our knowledge of SA biosynthesis and identifies TaICSA,as well as several additional candidate genes that encode transcription factors for regulating endogenous SA levels,as part of an efficient strategy for enhancing FHB resistance in wheat.展开更多
Phenylketonuria(PKU),a disease resulting in the disability to degrade phenylalanine(Phe)is an inborn error with a 1 in 10,000 morbidity rate on average around the world which leads to neurotoxicity.As an potential alt...Phenylketonuria(PKU),a disease resulting in the disability to degrade phenylalanine(Phe)is an inborn error with a 1 in 10,000 morbidity rate on average around the world which leads to neurotoxicity.As an potential alternative to a protein-restricted diet,oral intake of engineered probiotics degrading Phe inside the body is a promising treatment,currently at clinical stage II(Isabella,et al.,2018).However,limited transmembrane transport of Phe is a bottleneck to further improvement of the probiotic’s activity.Here,we achieved simultaneous degradation of Phe both intracellularly and extracellularly by expressing genes encoding the Phe-metabolizing enzyme phenylalanine ammonia lyase(PAL)as an intracellularly free and a cell surface-immobilized enzyme in Escherichia coli Nissle 1917(EcN)which overcomes the transportation problem.The metabolic engineering strategy was also combined with strengthening of Phe transportation,transportation of PAL-catalyzed trans-cinnamic acid and fixation of released ammonia.Administration of our final synthetic strain TYS8500 with PAL both displayed on the cell surface and expressed inside the cell to the Pah^(F263S)PKU mouse model reduced blood Phe concentration by 44.4%compared to the control Ec N,independent of dietary protein intake.TYS8500 shows great potential in future applications for PKU therapy.展开更多
Sphingosine-1-phosphate lyase （SPL） is involved in degrading the conserved sphingolipid signaling molecule sphingosine-1-phosphate. However, molecular studies on plant SPL have not been reported to date. Here, we pr...Sphingosine-1-phosphate lyase （SPL） is involved in degrading the conserved sphingolipid signaling molecule sphingosine-1-phosphate. However, molecular studies on plant SPL have not been reported to date. Here, we present bioinformatic, molecular and functional analyses of putative SPL proteins from Arabidopsis thaliana and rice （designated as AtSPL and OsSPL, respectively）. Amino acid sequence comparison revealed that plant SPL contalned the pyridoxal-dependent decarboxylase domain and the conserved residue that may be involved in substrate catalysis. When expressed in Saccharomyces cerevisiae, AtSPL and OsSPL corrected the hypersensitive phenotype of the yeast dpl1 deletion strain, which is deficient in endogenous SPL activity, to exogenous supplied sphingolipid long chain bases （LCBs）, suggesting that plant SPL protein is functional In vivo in degrading phosphorylated LCBs. In Arabidopsis, AtSPL transcripts were detected in roots, stems, leaves, flowers and siliques. In pAtSPL-AtSPL∷GUS transgenic lines, the AtSPL∷GUS fusion protein was found in a variety of vegetative and reproductive tissues. AtSPL expression level was dynamically regulated during leaf development and senescence, and was steadily and significantly increased in Arabidopsis seedlings treated with the cell death-inducing fungal toxin fumonisin B1. The potential function of SPL in Arabidopsis is discussed.展开更多
Background Isocitrate lyase （ICL） was previously demonstrated to play a pivotal role in the intracellular metabolism of Mycobacterium tuberculosis （MTB）. Presently several lines of evidence suggest that ICL from M...Background Isocitrate lyase （ICL） was previously demonstrated to play a pivotal role in the intracellular metabolism of Mycobacterium tuberculosis （MTB）. Presently several lines of evidence suggest that ICL from MTB （MTB-ICL） may play some roles in the interaction between MTB and host macrophage. However, there has been no research on the interaction between MTB-ICL and host macrophage.Methods MTB-icl and M. smegmatis （MS）-icl genes were amplified by polymerase chain reaction （PCR） and cloned into the E. coli-mycobacterium shuttle plasmid pUV15 to obtain recombinant shuttle plasmids pMTB-icl and pMS-icl. Following transformation into MS by electroporation, the expression of pMTB-icl and pMS-icl was verified by reverse transcriptase （RT）-PCR. The expression of recombinant plasmids derived from pUV15 when rMS was phagocytized by macrophage was also verified via fluorescence microscope. Ms 1-2c, rMS-pUV15, rMS-pMS-icl and rMS-pMTB-icl were used to infect RAW264.7 cells and the survival of intracellular MS was monitored by bacterial culture at 0, 24 and 48 hours after infection. The culture supernatants from macrophage infected by Ms 1-2c, rMS-pUV15, rMS-pMS-icl and rMS-pMTB-icl were collected and the interferon （IFN）-y and nitric oxide （NO） concentrations were measured by ELISA or by Griess assay, respectively. The apoptosis of macrophage was assayed by the in situ TUNEL technique.Results RT-PCR showed that both pMTB-icl and pMS-icl could be expressed in MS. Fluorescence microscopic observation showed that recombinant plasmids derived from pUV15 （pUV15-iG） could also be expressed in MS when MS were phagocytized by macrophage. Bacterial culture data demonstrated that rMS-pMTB-icl exhibited significantly increased intracellular survival in the murine macrophage cell line RAW264.7 compared with Ms 1-2c, rMS-pUV15 and rMS-pMS-icl. This increased intracellular survival was not accompanied by the upregulation of IFN-y and NO in host macrophage. But a lower apoptosis rate of macrophages 展开更多
基金Supported by UC discovery and NSF grants to KD. Publication of this paper is supported by the National Natural Science Foundation of China （30624808） and Science Publication Foundation of the Chinese Academy of Sciences.Acknowledgements The authors would like to acknowledge G. Raman for performing the jasmonate and aldehyde measurements.
文摘Plants have evolved complex signaling pathways to coordinate responses to developmental and environmental Information. The oxylipin pathway Is one pivotal lipid-based signaling network, composed of several competing branch pathways, that determines the plant＇s ability to adapt to various stimuli. Activation of the oxyllpln pathway Induces the de novo synthesis of biologically active metabolltes called ＂oxyllplns＂. The relative levels of these metabolltes are a distinct indicator of each plant species and determine the ability of plants to adapt to different stimuli. The two major branches of the oxyllpln pathway, allene oxide synthase （AOS） and hydroperoxlde lyase （HPL） are responsible for production of the signaling compounds, jasmonates and aldehydes respectively. Here, we compare and contrast the regulation of AOS and HPL branch pathways In rice and Arabidopsis as model monocotyledonous and dicotyledonous systems. These analyses provide new Insights Into the evolution of JAs and aldehydes signaling pathways, and the complex network of processes responsible for stress adaptations In monocots and dicots.
文摘In this study, the activities of phenylalanine ammonia lyase （PAL）, polyphenoloxidase （PPO）, and peroxidase （POD） were assayed in cucumber seedlings （Cucumis sativus L.） at 0, 6, 12, 24, 48, 72, and 96 h after they were infested by Bemisia tabaci （Gennadius） using spectrophotometric analysis. The results indicated that herbivore infestation increased the activities of PAL, PPO, and POD. The enzymes showed different activity levels at different times after the infestation. The PAL activity reached the first high peak by 23.1% at 6 h and the highest peak by 29.1% at 48 h compared to the control. The PPO activity reached the first high peak by 22.7% at 6 h and the highest peak by 52.6% at 24 h, and the POD activity reached the highest peak by 213.2% at 6 h and another higher peak value by 135.2% at 96 h. The results suggest that the enhanced activities of the enzymes may contribute to bioprotection of cucumber plants against B. tabaci infestation.
基金Supported by Specialized Research Fund for the Doctoral Program of Higher Education of China,No.20120142120048Natural Science Foundation of Hubei Province,China,No.2012FFB02308
文摘AIM: To investigate the association between endogenous hydrogen sulfide (H<sub>2</sub>S) and portal hypertension as well as its effect on vascular smooth muscle cells.
基金supported by grants from the National Natu-ral Science Foundation of China (81972779)Ministry of Education (MOE) Key Laboratory on signaling Regulation and Targeting Therapy of Liver Cancer,and Shanghai Key Laboratory of Hepato-biliary Tumor Biology,Chinese National Key Project (2018ZX10723204-006-003)。
文摘Background: Hepatocellular carcinoma(HCC) is one of the most highly malignant tumors. Liver tumor-initiating cells(LTICs) have been considered to contribute to HCC progression and metastasis. ATP-citrate lyase(ACLY), as a key enzyme for de novo lipogenesis, has been reported to be upregulated in various tumors. However, its expression and role in HCC and LTICs remain unknown. Methods: The expressions of ACLY in HCC tissues were detected by quantitative real-time PCR(q RT-PCR), Western blotting and immunohistochemistry. Kaplan-Meier curves and Chi-square test were used to determine the clinical significance of ACLY expression in HCC patients. A series of assays were performed to determine the function of ACLY on stemness, migration and invasion of HCC cells. Luciferase reporter assay, Western blotting and immunoprecipitation were used to study the regulation of the Wnt/β-catenin signaling by ACLY. Rescue experiments were performed to investigate whether β-catenin was the mediator of ACLY-regulated stemness and migration in HCC cells. Results: ACLY was highly expressed in HCC tissues and LTICs. Overexpression of ACLY was significantly correlated with poor prognosis, progression and metastasis of HCC patients. Knockdown of ACLY remarkably suppressed stemness properties, migration and invasion in HCC cells. Mechanistically, ACLY could regulate the canonical Wnt pathway by affecting the stability of β-catenin, and Lys49 acetylation of β-catenin might mediate ACLY-regulated β-catenin level in HCC cells. Conclusions: ACLY is a potent regulator of Wnt/β-catenin signaling in modulating LTICs stemness and metastasis in HCC. ACLY may serve as a new target for the diagnosis and treatment of HCC.
基金supported by the National Key Project for Research on Transgenic Plants (2009ZX08001-017B and 2011ZX08009-003-001)the National Natural Science Foundation of China (No. 30971880)+1 种基金the National High-tech R&D Program of China (No. 2 012AA101504)the Program for Changjiang Scholars and Innovative Research Team in the University of the Ministry of Education of China (No. IRT0943)
文摘Sphingolipids, including sphingosine-l-phosphate （SIP）, have been shown to function as signaling mediators to regulate diverse aspects of plant growth, development, and stress response. In this study, we performed functional analysis of a rice （Oryza sativa） SlP lyase gene OsSPL1 in transgenic tobacco plants and explored its possible involvement in abiotic stress response. Overexpression of OsSPL1 in transgenic tobacco resulted in enhanced sensitivity to exogenous abscisic acid （ABA）, and decreased tolerance to salt and oxidative stress, when compared with the wild type. Furthermore, the expression levels of some selected stress-related genes in OsSPLl-overexpressing plants were reduced after application of salt or oxidative stress, indicating that the altered responsiveness of stress-related genes may be responsible for the reduced tolerance in OsSPLl.overexpressing tobacco plants under salt and oxidative stress. Our results suggest that rice OsSPL1 plays an important role in abiotic stress responses.
文摘This review is concerned with the mechanisms controlling fruit softening.Master genetic regulators switch on the ripening programme and the regulatory pathway branches downstream,with separate controls for distinct quality attributes such as colour,flavour,texture,and aroma.Ethylene plays a critical role as a ripening hormone and is implicated in controlling different facets of ripening,including texture change,acting through a range of transcriptional regulators,and this signalling can be blocked using 1-methylcyclopropene.A battery of at least seven cell-wall-modifying enzymes,most of which are synthesized de novo during ripening,cause major alterations in the structure and composition of the cell wall components and contribute to the softening process.Significant differences between fruits may be related to the precise structure and composition of their cell walls and the enzymes recruited to the ripening programme during evolution.Attempts to slow texture change and reduce fruit spoilage by delaying the entire ripening process can often affect negatively other aspects of quality,and low temperatures,in particular,can have deleterious effects on texture change.Gene silencing has been used to probe the function of individual genes involved in different aspects of ripening,including colour,flavour,ethylene synthesis,and particularly texture change.The picture that emerges is that softening is a multi-genic trait,with some genes making a more important contribution than others.In future,it may be possible to control texture genetically to produce fruits more suitable for our needs.
基金supported by the National Program on Key Basic Research Projects (No.2012CB113900)Natural Science Foundation of China (No.31071805,31301790)+2 种基金Key Sci-Technology Project of Zhejiang Province (No.2010C12004)Guangdong Natural Science Foundation (S2013040016220)the China Postdoctoral Science Foundation (2013M530375)
文摘PECTATE LYASE‐LIKE10（PLL10） was previously identified as one of the differentially expressed genes both in microspores during the late pollen developmental stages and in pistils during the fertilization process in Chinese cabbage（Brassica campestris ssp. chinensis）. Here, antisense‐RNA was used to study the functions of BcPLL10 in Chinese cabbage. Abnormal pollen was identified in the transgenic lines（bcpll10‐4, ‐5, and ‐6）. In fertilization experiments, fewer seeds were harvested when the antisense‐RNA lines were used as pollen donor. In vivo and in vitro pollen germination assays less germinated pollen tubes were observed in bcpll10 lines. Scanning electron microscopy observation verified that the tryphine materials were over accumulated around the pollen surface and sticked them together in bcpll10.Moreover, transmission electron microscopy observation revealed that the internal endintine was overdeveloped and predominantly occupied the intine, and disturbed thenormal proportional distribution of the two layers in the non‐germinal furrow region; and no obvious demarcation existed between them in the germinal furrow region in the bcpll10 pollen. Collectively, this study presented a novel PLL gene that played an important role during the pollen wall development in B. campestris, which may also possess potential importance for male sterility usage in agriculture.
文摘Background Sphingosine-1-phosphate lyase insufficiency syndrome(SPLIS)or nephrotic syndrome type-14 is caused by biallelic mutations in SGPL1.Here,we conducted a systematic review to delineate the characteristics of SPLIS patients.Methods A literature search was performed in PubMed,Web of Science,and Scopus databases,and eligible studies were included.For all patients,demographic,clinical,laboratory,and molecular data were collected and analyzed.Results Fifty-five SPLIS patients(54.9%male,45.1%female)were identified in 19 articles.Parental consanguinity and positive family history were reported in 70.9%and 52.7%of patients,respectively.Most patients(54.9%)primarily manifested within the first year of life,nearly half of whom survived,while all patients with a prenatal diagnosis of SPLIS(27.5%)died at a median[interquartile(IQR)]age of 2(1.4–5.3)months(P=0.003).The most prevalent clinical feature was endocrinopathies,including primary adrenal insufficiency(PAI)(71.2%)and hypothyroidism(32.7%).Kidney disorders(42,80.8%)were mainly in the form of steroid-resistant nephrotic syndrome(SRNS)and progressed to end-stage kidney disease(ESKD)in 19(36.5%)patients at a median(IQR)age of 6(1.4–42.6)months.Among 30 different mutations in SGPL1,the most common was c.665G>A(p.Arg222Gln)in 11(20%)patients.Twenty-six(49.1%)patients with available outcome were deceased at a median(IQR)age of 5(1.5–30.5)months,mostly following ESKD(23%)or sepsis/septic shock(23%).Conclusion In patients with PAI and/or SRNS,SGPL1 should be added to diagnostic genetic panels,which can provide an earlier diagnosis of SPLIS and prevention of ESKD and other life-threatening complications.
文摘Carbohydrases secreted by marine Vibrio sp. YKW-34 with strong Laminaria cell wall degrading ability were screened, and among them alginate lyase was found to be dominant. The effects of medium composition and culturing condition on the produc- tion of alginate lyase by marine Vibrio sp. YKW-34 in flask were investigated in this study. In the culture medium of marine broth, no alginate lyase was produced. The activity of the alginate lyase, after being induced, reached 5 UmL–1. The best inoculum volume and inoculum age were 10% and 12 h, respectively. The optimal temperature for alginate lyase production was 25℃. The fermentation medium was composed of 0.5% of Laminaria powder and 0.2% of KNO3 with an initial acidity of pH 8.0. Alginate could induce alginate lyase production but not as efficiently as Laminaria powder did. The addition of fucoidan, cellulose and glucose had nega- tive effect on the alginate lyase production. Other kinds of nitrogen sources, such as yeast extract, beef extract and peptone, had posi- tive effect on the growth of the microorganism and negative effect on alginate lyase production. In addition, the time course of algi- nate lyase production under the optimized condition was described. The optimal harvest time was 48 h.
基金supported by the National Natural Science Foundation of China(3210170116)the Science and Technology Department of Sichuan Province(2022YFSY0035).
文摘Salicylic acid(SA),a vital endogenous hormone,plays a crucial role in plant growth and the response to abiotic and biotic stress.Isochorismate synthase(ICS)and phenylalanine ammonia lyase(PAL)are critical rate-limiting enzymes for SA synthesis.Fusarium head blight(FHB)seriously threatens the safety of wheat production,but increasing the content of SA can enhance FHB resistance.However,the pathway of SA synthesis and regulation in wheat remains unknown.In this study,three wheat ICS(TaICSA,TaICSB,and TaICSD)were identified,and their functions were validated in vitro for isomerizing chorismate to isochorismate.The mutation of one or two homoeoalleles of TaICSA,TaICSB,and TaICSD in the wheat variety‘Cadenza’reduced SA levels under ultraviolet treatment and Fusarium graminearum infection,further enhancing sensitivity to FHB.Overexpression of TaICSA can significantly enhance SA levels and resistance to FHB.To further study SA synthesis pathways in wheat and avoid interference with pathogenicity related genes,the leaves of wild-type Cadenza and different TaICS mutant lines were subjected to ultraviolet treatment for transcriptomic analysis.The results showed that 37 PALs might be involved in endogenous SA synthesis,and 82 WRKY and MYB family transcription factors may regulate the expression of ICS and PAL.These results were further confirmed by RT-PCR.In conclusion,this study expands our knowledge of SA biosynthesis and identifies TaICSA,as well as several additional candidate genes that encode transcription factors for regulating endogenous SA levels,as part of an efficient strategy for enhancing FHB resistance in wheat.
基金supported by the National Natural Science Foundation of China(21825804,31921006)the National Science&Technology Major Project“Key New Drug Creation and Manufacturing Program”,China(2018ZX09711002-019)the Shanghai Municipal Science and Technology Major Project and the National Key Research and Development Program of China(2018YFA0800603)。
文摘Phenylketonuria(PKU),a disease resulting in the disability to degrade phenylalanine(Phe)is an inborn error with a 1 in 10,000 morbidity rate on average around the world which leads to neurotoxicity.As an potential alternative to a protein-restricted diet,oral intake of engineered probiotics degrading Phe inside the body is a promising treatment,currently at clinical stage II(Isabella,et al.,2018).However,limited transmembrane transport of Phe is a bottleneck to further improvement of the probiotic’s activity.Here,we achieved simultaneous degradation of Phe both intracellularly and extracellularly by expressing genes encoding the Phe-metabolizing enzyme phenylalanine ammonia lyase(PAL)as an intracellularly free and a cell surface-immobilized enzyme in Escherichia coli Nissle 1917(EcN)which overcomes the transportation problem.The metabolic engineering strategy was also combined with strengthening of Phe transportation,transportation of PAL-catalyzed trans-cinnamic acid and fixation of released ammonia.Administration of our final synthetic strain TYS8500 with PAL both displayed on the cell surface and expressed inside the cell to the Pah^(F263S)PKU mouse model reduced blood Phe concentration by 44.4%compared to the control Ec N,independent of dietary protein intake.TYS8500 shows great potential in future applications for PKU therapy.
基金Supported by the National Natural Science Foundation of China （30521001） and the Chinese Academy of Sciences （KSCX2-SW-304）.Acknowledgments The authors are grateful to Drs Lu Liang and Yiping Tong for helpful discussion on this work and the writing of the manuscript.
文摘Sphingosine-1-phosphate lyase （SPL） is involved in degrading the conserved sphingolipid signaling molecule sphingosine-1-phosphate. However, molecular studies on plant SPL have not been reported to date. Here, we present bioinformatic, molecular and functional analyses of putative SPL proteins from Arabidopsis thaliana and rice （designated as AtSPL and OsSPL, respectively）. Amino acid sequence comparison revealed that plant SPL contalned the pyridoxal-dependent decarboxylase domain and the conserved residue that may be involved in substrate catalysis. When expressed in Saccharomyces cerevisiae, AtSPL and OsSPL corrected the hypersensitive phenotype of the yeast dpl1 deletion strain, which is deficient in endogenous SPL activity, to exogenous supplied sphingolipid long chain bases （LCBs）, suggesting that plant SPL protein is functional In vivo in degrading phosphorylated LCBs. In Arabidopsis, AtSPL transcripts were detected in roots, stems, leaves, flowers and siliques. In pAtSPL-AtSPL∷GUS transgenic lines, the AtSPL∷GUS fusion protein was found in a variety of vegetative and reproductive tissues. AtSPL expression level was dynamically regulated during leaf development and senescence, and was steadily and significantly increased in Arabidopsis seedlings treated with the cell death-inducing fungal toxin fumonisin B1. The potential function of SPL in Arabidopsis is discussed.
基金This work was supported by a grant from the National Natural Science Foundation of China （No. 30600528）.
文摘Background Isocitrate lyase （ICL） was previously demonstrated to play a pivotal role in the intracellular metabolism of Mycobacterium tuberculosis （MTB）. Presently several lines of evidence suggest that ICL from MTB （MTB-ICL） may play some roles in the interaction between MTB and host macrophage. However, there has been no research on the interaction between MTB-ICL and host macrophage.Methods MTB-icl and M. smegmatis （MS）-icl genes were amplified by polymerase chain reaction （PCR） and cloned into the E. coli-mycobacterium shuttle plasmid pUV15 to obtain recombinant shuttle plasmids pMTB-icl and pMS-icl. Following transformation into MS by electroporation, the expression of pMTB-icl and pMS-icl was verified by reverse transcriptase （RT）-PCR. The expression of recombinant plasmids derived from pUV15 when rMS was phagocytized by macrophage was also verified via fluorescence microscope. Ms 1-2c, rMS-pUV15, rMS-pMS-icl and rMS-pMTB-icl were used to infect RAW264.7 cells and the survival of intracellular MS was monitored by bacterial culture at 0, 24 and 48 hours after infection. The culture supernatants from macrophage infected by Ms 1-2c, rMS-pUV15, rMS-pMS-icl and rMS-pMTB-icl were collected and the interferon （IFN）-y and nitric oxide （NO） concentrations were measured by ELISA or by Griess assay, respectively. The apoptosis of macrophage was assayed by the in situ TUNEL technique.Results RT-PCR showed that both pMTB-icl and pMS-icl could be expressed in MS. Fluorescence microscopic observation showed that recombinant plasmids derived from pUV15 （pUV15-iG） could also be expressed in MS when MS were phagocytized by macrophage. Bacterial culture data demonstrated that rMS-pMTB-icl exhibited significantly increased intracellular survival in the murine macrophage cell line RAW264.7 compared with Ms 1-2c, rMS-pUV15 and rMS-pMS-icl. This increased intracellular survival was not accompanied by the upregulation of IFN-y and NO in host macrophage. But a lower apoptosis rate of macrophages
