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1.
Int J Nanomedicine ; 18: 3325-3338, 2023.
Article in English | MEDLINE | ID: mdl-37361386

ABSTRACT

Purpose: Due to its competitive advantages such as small size, high stability, easy production, and good tissue penetration compared with monoclonal antibodies (mAb), nanobodies (Nbs) were considered the next generation of therapeutics. However, the absence of Fc fragments and Fc-triggered immune effectors limits their clinical applications. In order to overcome these limitations, we develop a novel approach by attaching an IgG binding domain (IgBD) to Nbs for recruiting endogenous IgG and recovering the immune effectors for tumor killing. Material and Methods: We linked a Streptococcal Protein G-derived IgBD, termed C3Fab, at the C-terminus of a CD70-specific Nb 3B6 to construct an endogenous IgG recruitment antibody (termed EIR). The recombinant Nb3B6-C3Fab was expressed in E. coli BL21 (DE3) and purified by nickel affinity chromatography. We further evaluated the binding, recruitment of IgG, and the serum half-life of Nb3B6-C3Fab. The tumor-killing effects on CD70 positive cells mediated by antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity were also detected. Results: We successfully constructed a IgBD fused Nb3B6-C3Fab with high affinity for CD70 and mouse IgG (mIgG). Nb3B6-C3Fab can specifically bind to CD70 positive tumor cells and recruit mIgG on the cell surface. Ligating of Nb3B6 with C3Fab increased its serum half-life in mice almost 39-fold from 0.96 h to 37.67 h. Moreover, we demonstrated remarkable cytotoxicity of Nb3B6-C3Fab to CD70 positive tumor cells via C3Fab by immune effector cells. Conclusion: Our study demonstrates that IgBD fusion endows Nbs with the ability for endogenous IgG recruitment and half-life promotion. Linking IgBD to Nbs is an effective strategy to recovering immune effectors for tumor killing.


Subject(s)
Antibodies, Monoclonal , Neoplasms , Single-Domain Antibodies , Animals , Mice , Antibodies, Monoclonal/pharmacology , Escherichia coli , Immunoglobulin G/metabolism , Phagocytosis , Single-Domain Antibodies/pharmacology
2.
Gene ; 865: 147332, 2023 May 20.
Article in English | MEDLINE | ID: mdl-36871675

ABSTRACT

As a universal adaptor used by most TLR members, the myeloid differentiation factor 88 (MyD88) plays essential roles in TLR-mediated inflammatory response of invertebrate and vertebrate animals, and functional features of MyD88 remain largely unknown in amphibians. In this study, a MyD88 gene named Xt-MyD88 was characterized in the Western clawed frog (Xenopus tropicalis). Xt-MyD88 and MyD88 in other species of vertebrates share similar structural characteristics, genomic structures, and flanking genes, suggesting that MyD88 is structurally conserved in different phyla of vertebrates ranging from fish to mammals. Moreover, Xt-MyD88 was widely expressed in different organs/tissues, and was induced by poly(I:C) in spleen, kidney, and liver. Importantly, overexpression of Xt-MyD88 triggered a marked activation of both NF-κB promoter and interferon-stimulated response elements (ISREs), implying that it may be play important roles in inflammatory responses of amphibians. The research represents the first characterization on the immune functions of amphibian MyD88, and reveals considerable functional conservation of MyD88 in early tetrapods.


Subject(s)
Myeloid Differentiation Factor 88 , NF-kappa B , Animals , Xenopus/genetics , Xenopus/metabolism , Myeloid Differentiation Factor 88/genetics , Myeloid Differentiation Factor 88/metabolism , Amino Acid Sequence , NF-kappa B/genetics , NF-kappa B/metabolism , Biological Evolution , Mammals/metabolism
3.
Dev Comp Immunol ; 141: 104648, 2023 04.
Article in English | MEDLINE | ID: mdl-36708793

ABSTRACT

As one of interferon-induced serine/threonine kinases, the protein kinase R (PKR) plays vital roles in antiviral defense, and functional features of PKR remain largely unknown in amphibians, which suffer from ranaviral diseases in the last few decades. In this study, a PKR gene named Xt-PKR was characterized in the Western clawed frog (Xenopus tropicalis). Xt-PKR gene was widely expressed in different organs/tissues, and was rapidly induced by poly(I:C) in spleen, kidney, and liver. Intriguingly, Xt-PKR could be up-rugulated by the treatment of type I and type III interferons, and the transcript level of Xt-PKR induced by type I interferon was much higher than that of type III interferon. Moreover, overexpression of Xt-PKR can suppress the protein synthesis and ranavirus replication in vitro, and the residue lysine required for the translation inhibition activity in mammalian PKR is conserved in Xt-PKR. The present study represents the first characterization on the functions of amphibian PKR, and reveals considerable functional conservation of PKR in early tetrapods.


Subject(s)
Xenopus , eIF-2 Kinase , Animals , eIF-2 Kinase/genetics , eIF-2 Kinase/metabolism , Xenopus/metabolism , Gene Expression , Organ Specificity
4.
J Plant Physiol ; 280: 153905, 2023 Jan.
Article in English | MEDLINE | ID: mdl-36580705

ABSTRACT

Rice microRNA168a (osa-miR168a) plays important roles in mediating flowering time, grain yield and vigor, seeding growth, and immunity by targeting the RNA-induced silencing complex component Argonaute 1 (AGO1). However, the functions of miR168a exerted by targeting other genes require further clarification before it could be used in rice molecular breeding. In this study, we identified a new target gene of osa-miR168a-5p (miR168a-5p) in rice called OsOFP3 (ovate family protein 3) and investigated the roles of miR168a-5p in response to brassinosteroids (BRs), salt stress, and nitrogen allocation. Up- and downregulated miR168a-5p expression respectively decreased and increased the expression of the BR-negative regulator OsOPF3. The results of RNA ligase-mediated rapid amplification of cDNA ends (5'RLM-RACE) revealed cleavage sites in OsOPF3 and OsNPF2.4 mRNAs. The phenotype of miR168a-5p transgenic rice was BR-associated and included the lamina bending response to BR, short seeds, and low 1000-grain weight. MicroRNA 168a-5p also regulated the expression of the nitrate transporter, OsNPF2.4, which affected nitrogen allocation, and regulated OsAGO1a expression in response to salt stress. Taken together, rice miR168a-5p regulates BR-associated pathways, nitrogen transport, and stress by targeting OsOFP3, OsNPF2.4, and OsAGO1a, respectively, resulting in a series of important agronomic traits for rice breeding.


Subject(s)
Oryza , Oryza/metabolism , Salt Tolerance/genetics , Brassinosteroids/metabolism , Nitrate Transporters , Edible Grain/metabolism , Gene Expression Regulation, Plant , Plant Proteins/genetics , Plant Proteins/metabolism
5.
Article in Chinese | WPRIM (Western Pacific) | ID: wpr-986245

ABSTRACT

@#[摘 要] 目的:构建靶向CD70分子的重组免疫毒素,通过表达、纯化制备PE38与抗CD70纳米抗体重组蛋白,体外抗肿瘤实验探究重组蛋白是否对高表达CD70分子的阳性肿瘤细胞具有杀伤活性。方法:通过基因工程手段,将CD70纳米抗体Nb 2B3基因片段通过一个连接子与pET21a-PE38基因片段相连,获得重组表达载体pET21a-Nb 2B3-PE38并转入BL21(DE3)感受态细胞中进行表达、纯化与鉴定。用间接ELISA及FACS法检测Nb 2B3-PE38与CD70分子的结合活性,MTT法检测Nb 2B3-PE38对高表达CD70分子的肾透明细胞癌786-O细胞的体外杀伤活性,Annexin Ⅴ-FITC/PI双染法检测Nb 2B3-PE38对786-O细胞凋亡的影响。结果:成功构建抗CD70纳米抗体重组免疫毒素Nb 2B3-PE38,纯化获得纯度>90%的重组蛋白,SDS-PAGE及WB检测结果表明目的蛋白正确表达,分子量为56 000。纯化后的Nb 2B3-PE38能与重组CD70抗原及786-O细胞表面的CD70分子特异性结合;25 µg/mL Nb 2B3-PE38即对786-O细胞产生极显著的杀伤作用(P<0.001),并且促进786-O细胞的细胞凋亡(P<0.01),其杀伤效应强于阳性对照顺铂(P<0.01)。结论:成功制备了特异性靶向CD70分子的免疫毒素Nb 2B3-PE38,其能够有效杀伤786-O细胞并诱导细胞凋亡且效果强于顺铂。

6.
Plant Biotechnol J ; 19(1): 98-108, 2021 01.
Article in English | MEDLINE | ID: mdl-32643247

ABSTRACT

l-Theanine is a specialized metabolite in the tea (Camellia sinensis) plant which can constitute over 50% of the total amino acids. This makes an important contribution to tea functionality and quality, but the subcellular location and mechanism of biosynthesis of l-theanine are unclear. Here, we identified five distinct genes potentially capable of synthesizing l-theanine in tea. Using a nonaqueous fractionation method, we determined the subcellular distribution of l-theanine in tea shoots and roots and used transient expression in Nicotiana or Arabidopsis to investigate in vivo functions of l-theanine synthetase and also to determine the subcellular localization of fluorescent-tagged proteins by confocal laser scanning microscopy. In tea root tissue, the cytosol was the main site of l-theanine biosynthesis, and cytosol-located CsTSI was the key l-theanine synthase. In tea shoot tissue, l-theanine biosynthesis occurred mainly in the cytosol and chloroplasts and CsGS1.1 and CsGS2 were most likely the key l-theanine synthases. In addition, l-theanine content and distribution were affected by light in leaf tissue. These results enhance our knowledge of biochemistry and molecular biology of the biosynthesis of functional tea compounds.


Subject(s)
Camellia sinensis , Plant Proteins , Camellia sinensis/genetics , Glutamates , Plant Leaves/genetics , Plant Proteins/genetics , Tea
7.
J Agric Food Chem ; 68(39): 10842-10851, 2020 Sep 30.
Article in English | MEDLINE | ID: mdl-32866009

ABSTRACT

l-Theanine has a significant role in the taste of tea (Camellia sinensis) infusions. Our previous research indicated that the lower l-theanine metabolism in ethylamine and l-glutamate is a key factor that explains the higher content of l-theanine in albino tea with yellow or white leaves, compared with that of normal tea with green leaves. However, the specific genes encoding l-theanine hydrolase in tea remains unknown. In this study, CsPDX2.1 was cloned together with the homologous Arabidopsis PDX2 gene and the recombinant protein was shown to catalyze l-theanine hydrolysis into ethylamine and l-glutamate in vitro. There were higher CsPDX2.1 transcript levels in leaf tissue and lower transcripts in the types of albino (yellow leaf) teas compared with green controls. The subcellular location of ethylamine in tea leaves was shown to be in the mitochondria and peroxisome using a nonaqueous fractionation method. This study identified the l-theanine hydrolase gene and subcellular distribution of ethylamine in tea leaves, which improves our understanding of the l-theanine metabolism and the mechanism of differential accumulation of l-theanine among tea varieties.


Subject(s)
Camellia sinensis/metabolism , Ethylamines/metabolism , Glutamates/metabolism , Hydrolases/metabolism , Plant Leaves/enzymology , Plant Proteins/metabolism , Amino Acid Sequence , Camellia sinensis/chemistry , Camellia sinensis/enzymology , Camellia sinensis/genetics , Glutamic Acid/metabolism , Hydrolases/chemistry , Hydrolases/genetics , Plant Leaves/genetics , Plant Leaves/metabolism , Plant Proteins/chemistry , Plant Proteins/genetics , Protein Transport , Sequence Alignment
8.
J Agric Food Chem ; 68(37): 10109-10117, 2020 Sep 16.
Article in English | MEDLINE | ID: mdl-32829629

ABSTRACT

Linalool is abundant in tea leaves and contributes greatly to tea aroma. The two isomers of linalool, (R)-linalool and (S)-linalool, exist in tea leaves. Our study found that (R)-linalool was the minor isomer in nine of Camellia sinensis var. sinensis cultivars. The (R)-linalool synthase of tea plant CsRLIS was identified subsequently. It is a chloroplast-located protein and specifically catalyzes the formation of (R)-linalool in vitro and in vivo. CsRLIS was observed to be a stress-responsive gene and caused the accumulation of internal (R)-linalool during oolong tea manufacture, mechanical wounding, and insect attack. Further study demonstrated that the catalytic efficiency of CsRLIS was much lower than that of (S)-linalool synthase CsSLIS, which might explain the lower (R)-linalool proportion in C. sinensis var. sinensis cultivars. The relative expression levels of CsRLIS and CsSLIS may also affect the (R)-linalool proportions among C. sinensis var. sinensis cultivars. This information will help us understand differential distributions of chiral aroma compounds in tea.


Subject(s)
Acyclic Monoterpenes/chemistry , Camellia sinensis/enzymology , Hydro-Lyases/metabolism , Plant Proteins/metabolism , Acyclic Monoterpenes/metabolism , Biocatalysis , Camellia sinensis/chemistry , Camellia sinensis/genetics , Camellia sinensis/metabolism , Chloroplasts/enzymology , Chloroplasts/genetics , Chloroplasts/metabolism , Hydro-Lyases/chemistry , Hydro-Lyases/genetics , Odorants/analysis , Plant Proteins/chemistry , Plant Proteins/genetics , Stereoisomerism , Tea/chemistry
9.
Biochem Biophys Res Commun ; 529(1): 91-96, 2020 08 13.
Article in English | MEDLINE | ID: mdl-32560825

ABSTRACT

As structural components of biological membranes, phytosterols are essential not only for a variety of cellular functions but are also precursors for brassinosteroid (BR) biosynthesis. Plant CYP51 is the oldest and most conserved obtusifoliol 14α-demethylase in eukaryotes and is an essential component of the sterol biosynthesis pathway. However, little is known about rice (Oryza sativa L.) CYP51G1. In this study, we showed that rice OsCYP51G1 shared high homology with obtusifoliol 14α-demethylase and OsCYP51G1 was strongly expressed in most of rice organs. Subcellular localization analysis indicated that OsCYP51G1 was localized to the endoplasmic reticulum. Knockdown and knockout of OsCYP51G1 resulted in delayed flowering, impaired membrane integrity, abnormal pollen, and reduced grain yield, whereas OsCYP51G1 overexpression led to increased grain yield. Knockdown of OsCYP51G1 also reduced the levels of end-products (sitosterol and stigmasterol) and increased those of upstream intermediates (24-methylene-cycloartenol and cycloeucalenol) of the OsCYP51G1-mediated sterol biosynthesis step. In contrast, overexpression of OsCYP51G1 increased the sitosterol and stigmasterol content and reduced that of cycloeucalenol. However, knockdown of OsCYP51G1 by RNAi did not elicit these BR deficiency-related phenotypes, such as dwarfism, erect leaves and small seeds, nor was the leaf lamina angle sensitive to brassinolide treatment. These results revealed that rice OsCYP15G1 encodes an obtusifoliol 14α-demethylase for the phytosterols biosynthesis and possible without affecting the biosynthesis of downstream BRs, which was different from its homolog, OsCYP51G3.


Subject(s)
Oryza/metabolism , Phytosterols/biosynthesis , Plant Proteins/metabolism , Sterol 14-Demethylase/metabolism , Brassinosteroids/biosynthesis , Gene Expression Regulation, Plant , Gene Knockdown Techniques , Gene Knockout Techniques , Genes, Plant , Germination/genetics , Oryza/genetics , Oryza/growth & development , Plant Proteins/genetics , Plants, Genetically Modified , Pollen/growth & development , Pollen/metabolism , RNA Interference , Seeds/growth & development , Seeds/metabolism , Sterol 14-Demethylase/genetics
10.
Front Plant Sci ; 11: 588, 2020.
Article in English | MEDLINE | ID: mdl-32582228

ABSTRACT

Enhancing nitrogen (N) use efficiency is a potential way to reduce excessive nitrogen application and increase yield. Autophagy is a conserved degradation system in the evolution of eukaryotic cells and plays an important role in plant development and stress response. Autophagic cores have two conjugation pathways that attach the product of autophagy-related gene 8 (ATG8) to phosphatidylethanolamine (PE) and ATG5 to ATG12, respectively, which then help with vesicle elongation and enclosure. Rice has six ATG8 genes, which have not been functionally confirmed so far. We identified the rice gene OsATG8b and characterized its role in N remobilization to affect grain quality by generating transgenic plants with its over-expression and knockdown. Our study confirmed the autophagy activity of OsATG8b through the complementation of the yeast autophagy-defective mutant scatg8 and by observation of autophagosome formation in rice. The autophagy activity is higher in OsATG8b-OE lines and lower in OsATG8b-RNAi than that in wild type (ZH11). 15N pulse-chase analysis revealed that OsATG8b-OE plants conferred higher N recycling efficiency to grains, while OsATG8b-RNAi transgenic plants exhibited lower N recycling efficiency and poorer grain quality. The autophagic role of OsATG8b was experimentally confirmed, and it was concluded that OsATG8b-mediated autophagy is involved in N recycling to grains and contributes to the grain quality, indicating that OsATG8b may be a potential gene for molecular breeding and cultivation of rice.

11.
Acta Chim Slov ; 67(4): 1281-1289, 2020 Dec.
Article in English | MEDLINE | ID: mdl-33533465

ABSTRACT

Two vanadium(V) complexes derived from the bromo and chloro-substituted hydrazones N'-(4-bromo-2-hydroxybenzylidene)- 2-chlorobenzohydrazide (H2L1) and N'-(3-bromo-5-chloro-2-hydroxybenzylidene)-3-methylbenzohydrazide (H2L2) with the formula [VOL1(OCH3)(CH3OH)] (1) and [VOL2(OCH3)(CH3OH)] (2) were newly synthesized and characterized by IR, UV-Vis and 1H NMR spectroscopy. The structures of H2L1 and the complexes were further confirmed by single crystal X-ray diffraction. Both vanadium complexes are mononuclear, with the metal atoms coordinated by the hydrazone ligands, methanol ligands, and methanolate ligands, and the oxo groups, forming octahedral geometry. The hydrazones and the vanadium complexes were assayed for the antimicrobial activities on Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Pseudomonas fluorescence, and the fungi Candida albicans and Aspergillus niger. The existence of the bromo and chloro groups in the hydrazone ligands may improve the antimicrobial property.


Subject(s)
Anti-Bacterial Agents/pharmacology , Antifungal Agents/pharmacology , Coordination Complexes/pharmacology , Hydrazones/pharmacology , Anti-Bacterial Agents/chemical synthesis , Antifungal Agents/chemical synthesis , Aspergillus niger/drug effects , Bacteria/drug effects , Candida albicans/drug effects , Coordination Complexes/chemical synthesis , Hydrazones/chemical synthesis , Ligands , Microbial Sensitivity Tests , Molecular Structure , Vanadium/chemistry
12.
Food Chem ; 305: 125440, 2020 Feb 01.
Article in English | MEDLINE | ID: mdl-31494496

ABSTRACT

Tea (Camellia sinensis) contains two active glutamate decarboxylases (CsGADs), whose unclear properties were examined here. CsGAD1 was 4-fold higher than CsGAD2 in activity. Their Km values for L-glutamate were around 5 mM. CsGAD1 and CsGAD2 performed best at 55 and 40 °C, respectively, and were both stimulated by calcium/calmodulin (Ca2+/CaM). Over 40 °C, their calmodulin-binding domains degraded. CsGADs were most active at pH 5.6, and were stimulated by Ca2+/CaM at pH 5.6-6.6, but inactivated at pH 3.6. Ca2+/CaM restored the CsGAD1 activity suppressed by inhibitors. CsGADs and CsCaM were localized to the cytosol. CsGAD1 was more highly expressed in most tissues, while CsGAD2 expression was more induced under stresses. The characteristics we first elucidated here revealed that CsGAD1 is the predominant isoform in tea plant, with CsGAD2 exhibiting a supplementary role under certain conditions. The information will contribute to regulation of GABA tea quality.


Subject(s)
Camellia sinensis/enzymology , Glutamate Decarboxylase/metabolism , Plant Proteins/metabolism , gamma-Aminobutyric Acid/metabolism , Droughts , Enzyme Stability , Glutamic Acid/metabolism , Hydrogen-Ion Concentration , Isoenzymes/metabolism , Kinetics , Temperature
13.
J Exp Bot ; 71(1): 168-177, 2020 01 01.
Article in English | MEDLINE | ID: mdl-31559427

ABSTRACT

LAZY1 family genes play important roles in both shoot and root gravitropism in plants. Here we report a Lotus japonicus mutant that displays negative gravitropic response in primary and lateral roots. Map-based cloning identified the mutant gene LAZY3 as a functional ortholog of the LAZY1 gene. Mutation of the LAZY3 gene reduced rootward polar auxin transport (PAT) in the primary root, which was also insensitive to the PAT inhibitor N-1-naphthylphthalamic acid. Moreover, immunolocalization of enhanced green fluorescent protein-tagged LAZY3 in L. japonicus exhibited polar localization of LAZY3 on the plasma membrane in root stele cells. We therefore suggest that the polar localization of LAZY3 in stele cells might be required for PAT in L. japonicus root. LAZY3 transcripts displayed asymmetric distribution at the root tip within hours of gravistimulation, while overexpression of LAZY3 under a constitutive promoter in lazy3 plants rescued the gravitropic response in roots. These data indicate that root gravitropism depends on the presence of LAZY3 but not on its asymmetric expression in root tips. Expression of other LAZY genes in a lazy3 background did not rescue the growth direction of roots, suggesting that the LAZY3 gene plays a distinct role in root gravitropism in L. japonicus.


Subject(s)
Gravitropism/genetics , Lotus/genetics , Plant Proteins/genetics , Plant Roots/physiology , Lotus/growth & development , Lotus/metabolism , Plant Proteins/metabolism , Plant Roots/growth & development
14.
PLoS One ; 14(9): e0221076, 2019.
Article in English | MEDLINE | ID: mdl-31509542

ABSTRACT

BACKGROUND: Obesity is highly prevalent worldwide. More and more studies have been conducted on the relationship between H. pylori infection and obesity or overweight. But the relationship between them is controversial in the literatures and there is no comprehensive evidence for the correlation. AIM: To evaluate the prevalence of H. pylori infection in Chinese adult subjects who received routine physical examinations and the relationship between H. pylori and obesity. METHODS: Literatures on H. pylori infection and obesity in Chinese population were searched in online databases. Relevant data were extracted independently by two researchers and meta-analysis was performed by using Review manager 5.3 software. RESULTS: 22 articles were selected with a total sample size of 178033. The pooled prevalence of H. pylori was 42% (95%CI: 37% to 47%) and mean difference of BMI between subjects with and without H. pylori infection was 0.94 (95%CI: -0.04 to 1.91). 9 eligible studies with 27111 subjects were used to calculated pooled OR value because they contained obesity groups. The OR value showed that H. pylori-positive subjects tended to be obese at a risk of 1.20 (95% CI: 1.13 to 1.28). CONCLUSION: In China, obesity has association with H. pylori infection. H. pylori infection may be one of the risk factors for obesity.


Subject(s)
Helicobacter Infections/complications , Helicobacter Infections/epidemiology , Helicobacter pylori , Obesity/epidemiology , Obesity/etiology , Adult , Age Factors , Aged , Biomarkers , Body Mass Index , China/epidemiology , Cross-Sectional Studies , Databases, Factual , Female , Helicobacter Infections/microbiology , Humans , Male , Middle Aged , Population Surveillance , Prevalence , Risk Factors
16.
J Agric Food Chem ; 67(23): 6541-6550, 2019 Jun 12.
Article in English | MEDLINE | ID: mdl-31125230

ABSTRACT

The enzymatic hydrolysis of glycosidically bound volatiles (GBVs) plays an important role in tea aroma formation during the tea manufacturing process. However, during the enzyme-active manufacturing process of oolong tea, most GBVs showed no reduction, while ( Z)-3-hexenyl-ß-glucopyranoside significantly enhanced at the turnover stage. This study aimed to determine the reason for this increase in ( Z)-3-hexenyl-ß-glucopyranoside. Continuous wounding stress in the turnover stage did not enhance the expression level of glycosyltransferase 1 ( CsGT1), while it induced a significant increase in the ( Z)-3-hexenol content ( p ≤ 0.05). Furthermore, observing the cell structures of tea leaves exposed to continuous wounding and subcellular localizations of CsGTs suggested that the interaction of ( Z)-3-hexenol (substrate) and CsGT1 (enzyme) was available. In conclusion, both continuous wounding and subcellular localizations led to a ( Z)-3-hexenyl-ß-glucopyranoside enhancement mechanism during the oolong tea's turnover stage. These results advance our understanding of GBV formation during the tea manufacturing process and their relationship with the stress from the tea manufacturing process. In addition, the information will help us further evaluate contribution of GBVs to enzymatic formation of oolong tea aroma compounds.


Subject(s)
Camellia sinensis/chemistry , Food Handling/methods , Glucosides/analysis , Camellia sinensis/enzymology , Camellia sinensis/genetics , Camellia sinensis/physiology , Glycosyltransferases/genetics , Glycosyltransferases/metabolism , Plant Leaves/chemistry , Plant Leaves/physiology , Plant Proteins/genetics , Plant Proteins/metabolism , Stress, Physiological , Volatile Organic Compounds/analysis
17.
Int J Mol Sci ; 21(1)2019 Dec 31.
Article in English | MEDLINE | ID: mdl-31906256

ABSTRACT

Attachment of glycosylphosphatidylinositols (GPIs) to the C-termini of proteins is one of the most common posttranslational modifications in eukaryotic cells. GPI8/PIG-K is the catalytic subunit of the GPI transamidase complex catalyzing the transfer en bloc GPI to proteins. In this study, a T-DNA insertional mutant of rice with temperature-dependent drooping and fragile (df) shoots phenotype was isolated. The insertion site of the T-DNA fragment was 879 bp downstream of the stop codon of the OsGPI8 gene, which caused introns retention in the gene transcripts, especially at higher temperatures. A complementation test confirmed that this change in the OsGPI8 transcripts was responsible for the mutant phenotype. Compared to control plants, internodes of the df mutant showed a thinner shell with a reduced cell number in the transverse direction, and an inhomogeneous secondary wall layer in bundle sheath cells, while many sclerenchyma cells at the tops of the main veins of df leaves were shrunken and their walls were thinner. The df plants also displayed a major reduction in cellulose and lignin content in both culms and leaves. Our data indicate that GPI anchor proteins play important roles in biosynthesis and accumulation of cell wall material, cell shape, and cell division in rice.


Subject(s)
Introns , Oryza , Phenotype , Plant Leaves , Plant Shoots , Temperature , Acyltransferases/genetics , Acyltransferases/metabolism , Cell Wall/genetics , Cell Wall/metabolism , Glycosylphosphatidylinositols/genetics , Glycosylphosphatidylinositols/metabolism , Mutagenesis, Insertional , Oryza/genetics , Oryza/metabolism , Plant Leaves/genetics , Plant Leaves/metabolism , Plant Proteins/genetics , Plant Proteins/metabolism , Plant Shoots/genetics , Plant Shoots/metabolism
18.
Food Chem ; 270: 17-24, 2019 Jan 01.
Article in English | MEDLINE | ID: mdl-30174031

ABSTRACT

Aromatic aroma compounds contribute to flavor of tea (Camellia sinensis (L.) O. Kuntze) and they are mostly derived from l-phenylalanine via trans-cinnamic acid or directly from l-phenylalanine. The objective of this study was to investigate whether an alternative pathway derived from l-phenylalanine via phenylpyruvic acid is involved in formation of aroma compounds in tea. Enzyme reaction with phenylpyruvic acid showed that benzaldehyde, benzyl alcohol, and methyl benzoate were derived from phenylpyruvic acid in tea leaves. Feeding experiments using [2H8]l-phenylalanine indicated that phenylpyruvic acid was derived from l-phenylalanine in a reaction catalyzed by aromatic amino acid aminotransferases (AAATs). CsAAAT1 showed higher catalytic efficiency towards l-phenylalanine (p ≤ 0.001) while CsAAAT2 showed higher catalytic efficiency towards l-tyrosine (p ≤ 0.001). Both CsAAATs were localized in the cytoplasm of leaf cells. In conclusion, an alternative pathway for the formation of aromatic aroma compounds derived from l-phenylalanine via phenylpyruvic acid occurred in tea leaves.


Subject(s)
Phenylalanine/analysis , Phenylpyruvic Acids/analysis , Plant Leaves/chemistry , Tea/chemistry , Camellia sinensis/chemistry
19.
Food Chem ; 276: 93-100, 2019 Mar 15.
Article in English | MEDLINE | ID: mdl-30409668

ABSTRACT

l-Theanine is a specialized metabolite in tea (Camellia sinensis) leaves that contributes to tea function and quality. Yellow tea leaves (albino) generally have higher l-theanine contents than green tea leaves (normal), but the reason is unknown. The objective of this study was to investigate why l-theanine is accumulated in yellow tea leaves. We compared original normal leaves (green) and light-sensitive albino leaves (yellow) of cv. Yinghong No. 9. The l-theanine content was significantly higher in yellow leaves than in green leaves (p ≤ 0.01). After supplementation with [2H5]-l-theanine, yellow leaves catabolized less [2H5]-l-theanine than green leaves (p ≤ 0.05). Furthermore, most plants contained the enzyme catalyzing l-theanine conversion to ethylamine and l-glutamic acid. In conclusion, l-theanine accumulation in albino-induced yellow tea leaves was due to weak l-theanine catabolism. The differential accumulation mechanism differed from the l-theanine accumulation mechanism in tea and other plants.


Subject(s)
Camellia sinensis/chemistry , Glutamates/analysis , Plant Leaves/chemistry , Camellia sinensis/metabolism , Ethylamines/analysis , Ethylamines/metabolism , Glutamates/metabolism , Glutamic Acid/analysis , Glutamic Acid/metabolism , Hydrolases/metabolism , Plant Leaves/metabolism
20.
Int J Mol Sci ; 19(8)2018 Aug 18.
Article in English | MEDLINE | ID: mdl-30126188

ABSTRACT

Jasmonic acid (JA) is reportedly involved in the interaction between insects and the vegetative parts of horticultural crops; less attention has, however, been paid to its involvement in the interaction between insects and the floral parts of horticultural crops. Previously, we investigated the allene oxide synthase 2 (AOS2) gene that was found to be the only JA synthesis gene upregulated in tea (Camellia sinensis) flowers exposed to insect (Thrips hawaiiensis (Morgan)) attacks. In our present study, transient expression analysis in Nicotiana benthamiana plants confirmed that CsAOS2 functioned in JA synthesis and was located in the chloroplast membrane. In contrast to tea leaves, the metabolite profiles of tea flowers were not significantly affected by 10 h JA (2.5 mM) treatment as determined using ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry, and gas chromatography-mass spectrometry. Moreover, JA treatment did not significantly influence ethylene formation in tea flowers. These results suggest that JA in tea flowers may have different functions from JA in tea leaves and other flowers.


Subject(s)
Camellia sinensis/metabolism , Cyclopentanes/metabolism , Ethylenes/metabolism , Intramolecular Oxidoreductases/metabolism , Oxylipins/metabolism , Plant Proteins/metabolism , Biosynthetic Pathways , Metabolome
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