Protein arginine methyltransferase-6 regulates heterogeneous nuclear ribonucleoprotein-F expression and is a potential target for the treatment of neuropathic pain

Protein arginine methyltransferase-6 participates in a range of biological functions,particularly RNA processing,transcription,chromatin remodeling,and endosomal trafficking.However,it remains unclear whether protein arginine methyl transferase-6 modifies neuropathic pain and,if so,what the mechanisms of this effect.In this study,protein arginine methyltransferase-6 expression levels and its effect on neuropathic pain were investigated in the spared nerve injury model,chronic constriction injury model and bone cancer pain model,using immunohistochemistry,western blotting,immunoprecipitation,and label-free proteomic analysis.The results showed that protein arginine methyltransferase-6 mostly co-localized withβ-tubulinⅢin the dorsal root ganglion,and that its expression decreased following spared nerve injury,chronic constriction injury and bone cancer pain.In addition,PRMT6 knockout(Prmt6~(-/-))mice exhibited pain hypersensitivity.Furthermore,the development of spared nerve injury-induced hypersensitivity to mechanical pain was attenuated by blocking the decrease in protein arginine methyltransferase-6 expression.Moreover,when protein arginine methyltransferase-6 expression was downregulated in the dorsal root ganglion in mice without spared nerve injury,increased levels of phosphorylated extracellular signal-regulated kinases were observed in the ipsilateral dorsal horn,and the response to mechanical stimuli was enhanced.Mechanistically,protein arginine methyltransferase-6 appeared to contribute to spared nerve injury-induced neuropathic pain by regulating the expression of heterogeneous nuclear ribonucleoprotein-F.Additionally,protein arginine methyltransfe rase-6-mediated modulation of hete rogeneous nuclear ribonucleoprotein-F expression required amino atids 319 to 388,but not classical H3R2 methylation.These findings indicated that protein arginine methyltransferase-6 is a potential therapeutic target fo r the treatment of peripheral neuro pathic pain.

Expression and Characterization of ArgR, An Arginine Regulatory Protein in Corynebacterium crenatum

Objective Corynebacterium crenatum MT, a mutant from C. crenatum AS 1.542 with a lethal argR gene, exhibits high arginine production. To confirm the effect of ArgR on arginine biosynthesis in C. crenatum, an intact argR gene from wild-type AS 1.542 was introduced into C. crenatum MT, resulting in C. crenatum MT. sp, and the changes of transcriptional levels of the arginine biosynthetic genes and arginine production were compared between the mutant strain and the recombinant strain. Methods Quantitative real-time polymerase chain reaction was employed to analyze the changes of the related genes at the transcriptional level, electrophoretic mobility shift assays were used to determine ArgR binding with the argCJBDF, argGH, and carAB promoter regions, and arginine production was determined with an automated amino acid analyzer. Results Arginine production assays showed a 69.9% reduction in arginine from 9.01±0.22 mg/mL in C. crenatum MT to 2.71±0.13 mg/mL （P〈0.05） in C. crenatum MT. sp. The argC, argB, argD, argF, argJ, argG, and carA genes were down-regulated significantly in C. crenatum MT. sp compared with those in its parental C. crenatum MT strain. The electrophoretic mobility shift assays showed that the promoter regions were directly bound to the ArgR protein. Conclusion The arginine biosynthetic genes in C crenatum are clearly controlled by the regulator ArgR, and intact ArgR in C. crenatum MT results in a significant descrease in production. negative arginine production.

The optimal dietary arginine level of laying hens fed with low-protein diets

Background:Arginine(Arg)is an essential amino acid(EAA)in poultry,an important substrate for protein synthesis and a precursor of several molecules.Supplementation of EAAs with low protein(LP)diet increases the utilization efficiency of dietary crude protein(CP).However,if the EAA requirement is changed in hens fed a LP diet remains to be elucidated.The aim of the present study was to evaluate the optimal level of dietary Arg in the LP diet of hens.A total of 1350 Hy-Line Brown laying hens were randomly allocated to six dietary treatments:a basal diet(16%CP,positive control),or an isoenergetic LP diet(14%CP,0.80%Arg)supplemented 0,0.05%,0.10%,0.15%,and 0.20%L-Arg,corresponding to 0.80%,0.85%,0.90%,0.95%and 1.00%dietary Arg,respectively.Results:The feed efficiency was decreased(P<0.05)by 0.80%and 1.00%Arg-LP diets,compared to control.Within LP diets,dietary Arg level had significant quadratic effects(P<0.05)on laying rate,egg mass,and feed efficiency.Compared to control,the plasma CAT activity or T-AOC content were decreased by 0.80%(P<0.001).However,the hens offered 0.85%and 0.90%Arg-LP diets had higher CAT activity(P<0.001)than 0.80%Arg-LP diet.In contrast,1.00%Arg-LP group had the highest MDA and the lowest T-AOC content in plasma,liver,duodenal and jejunal mucosa(P<0.05).Compared to control,the villus height was decreased by 0.80%,0.95%and 1.00%Arg-LP diets,while the villus height to crypt depth(V/C)ratio was reduced by 0.95%and 1.00%Arg-LP diets in duodenum.Conclusion:The result demonstrates that LP diet(14%CP)deficient in Arg(0.80%Arg)result in augmented oxidative damage and impaired development of intestinal mucosa.According to the quadratic broken-line regression model,the optimal dietary arginine levels for Hy-Line Brown laying hens fed with low protein diet(14%CP)aged 33 to 40 weeks are 0.85%,0.86%,and 0.86%to obtained the maximum laying rate,egg mass,and feed efficiency,respectively.

Screening of Substrates of Protein Arginine Methyltransferase 1 in Glioma

Objective To screen the asymmetric dimethyl arginines (ADMA)-containing proteins which could combine with protein arginine methyltransferase 1 (PRMT1). Methods Western blot was adopted to identify the expression of PRMT1 and the proteins with ADMA in glioma cell lines and normal brain tissues, and then to detect the changes of ADMA level after knock-down of PRMT1 with RNAi transfection in U87MG cells. Co-Immunoprecipitation (Co-IP), western blot, and sliver staining were employed to screen the candidate binding proteins of PRMT1. Then liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to identify the binding proteins of PRMT1. Results The expression of PRMT1 and some levels of ADMA were higher in glioma cell lines than in normal brain tissues. After knocking down PRMT1, some ADMA levels were found declined. After screening the binding proteins of PRMT1 with Co-IP and LC-MS/MS, 26 candidate binding proteins were identified. Among them, 6 candidate proteins had higher ions scores (>38) and bioinformation analysis predicted that SEC23-IP, ANKHD1-EIF4EBP3 protein, and 1-phosphatidylinositol-3-phosphate 5-kinase isoform 2 had possible methylated aginine sites. Conclusions The high expression of PRMT1 in glioma may induce the change of ADMA levels. Altogether 26 candidate proteins were identified, which contain ADMA and specifically bind with PRMT1.

Combining protein arginine methyltransferase inhibitor and antiprogrammed death-ligand-1 inhibits pancreatic cancer progression

BACKGROUND Immunotherapy targeting programmed death-1(PD-1)or programmed deathligand-1(PD-L1)has been shown to be effective in a variety of malignancies but has poor efficacy in pancreatic ductal adenocarcinoma(PDAC).Studies have shown that PD-L1 expression in tumors is an important indicator of the efficacy of immunotherapy.Tumor cells usually evade chemotherapy and host immune surveillance by epigenetic changes.Protein arginine methylation is a common posttranslational modification.Protein arginine methyltransferase(PRMT)1 is deregulated in a wide variety of cancer types,whose biological role in tumor immunity is undefined.AIM To investigate the combined effects and underlying mechanisms of anti-PD-L1 and type I PRMT inhibitor in pancreatic cancer in vivo.METHODS PT1001B is a novel type I PRMT inhibitor with strong activity and good selectivity.A mouse model of subcutaneous Panc02-derived tumors was used to evaluate drug efficacy,toxic and side effects,and tumor growth in vivo.By flow cytometry,we determined the expression of key immune checkpoint proteins,detected the apoptosis in tumor tissues,and analyzed the immune cells.Immunohistochemistry staining for cellular proliferation-associated nuclear protein Ki67,TUNEL assay,and PRMT1/PD-L1 immunofluorescence were used to elucidate the underlying molecular mechanism of the antitumor effect.RESULTS Cultured Panc02 cells did not express PD-L1 in vitro,but tumor cells derived from Panc02 transplanted tumors expressed PD-L1.The therapeutic efficacy of anti-PD-L1 mAb was significantly enhanced by the addition of PT1001B as measured by tumor volume(1054.00±61.37 mm3 vs 555.80±74.42 mm3,P<0.01)and tumor weight(0.83±0.06 g vs 0.38±0.02 g,P<0.05).PT1001B improved antitumor immunity by inhibiting PD-L1 expression on tumor cells(32.74%±5.89%vs 17.95%±1.92%,P<0.05).The combination therapy upregulated tumorinfiltrating CD8+T lymphocytes(23.75%±3.20%vs 73.34%±4.35%,P<0.01)and decreased PD-1+leukocytes(35.77%±3.30%vs 6.48%±1.08%,P<0.001)in tumor tissue compared to the control.In addition,PT1001B amplified the inhibitory effect of anti-PD-L1 on tumor cell proliferation and enhanced the induction of tumor cell apoptosis.PRMT1 downregulation was correlated with PD-L1 downregulation.CONCLUSION PT1001B enhances antitumor immunity and combining it with anti-PD-L1 checkpoint inhibitors provides a potential strategy to overcome anti-PD-L1 resistance in PDAC.

Shrimp arginine kinase being a binding protein of WSSV envelope protein VP31

Viral entry into the host is the earliest stage of infection in the viral life cycle in which attachment proteins play a key role. VP31(WSV340/WSSV396), an envelope protein of white spot syndrome virus(WSSV), contains an Arg-Gly-Asp(RGD) peptide domain known as a cellular attachment site. At present, the process of VP31 interacting with shrimp host cells has not been explored. Therefore, the VP31 gene was cloned into p ET30a(+), expressed in Escherichia coli strain BL21 and purifi ed with immobilized metal ion affi nity chromatography. Four gill cellular proteins of shrimp( Fenneropenaeus c hinensis) were pulled down by an affi nity column coupled with recombinant VP31(r VP31), and the amino acid sequences were identifi ed with MALDI-TOF/TOF mass spectrometry. Hemocyanin, beta-actin, arginine kinase(AK), and an unknown protein were suggested as the putative VP31 receptor proteins. SDS-PAGE showed that AK is the predominant binding protein of VP31. An i n vitro binding activity experiment indicated that recombinant AK's(r AK) binding activity with r VP31 is comparable to that with the same amount of WSSV. These results suggested that AK, as a member of the phosphagen kinase family, plays a role in WSSV infection. This is the fi rst evidence showing that AK is a binding protein of VP31. Further studies on this topic will elucidate WSSV infection mechanism in the future.

Effect of Chronic Supplementation with L-Arginine on the Expression of Proteins that Regulate Muscle Protein Synthesis in Rats Trained in High-Intensity Exercise

Arginine is a conditionally essential amino acid that has been correlated with muscle protein synthesis. In order to investigate the effect of chronic supplementation of L-arginine on muscle protein synthesis via mTOR （mammalian target of rapamycin）, and contribute to the new scientific discussions on this amino acid in this context, adult male Wistar rats weighing about 200 g each were used, divided into four groups： TA （trained arginine）, SA （sedentary arginine）, CT （diet-control trained）, and CS （diet-control sedentary）. The diets were based on proposal A1N-93 （American Institute of Nutrition-1993）, in which one of them was enriched with 2% of arginine and the other with a mix of nonessential amino acids. Training of the animals consisted of sessions composed of four series of 10 jumps in a tank of water. Jumps were performed with a load of 50% of animals＇ body weight, five days a week for six weeks. Blood analyses done were insulin, glucose, amino acids, IGF-1 （insulin-like growth factor 1）, 1GFBP-3 （insulin-like growth factor-binding protein 3）, urea, and creatinine, as well as muscle and liver IGF-1. Molecular analyses were for IRS-1 （insulin receptor substrate 1）, PKB （protein kinase B）, also known as Akt, roTOR, 4E-BP1 （eukaryotic initiation factor 4E-binding protein 1） and p70S6K （p70 S6 kinase） by Western Blotting method. As a result, no statistically significant differences were found in the parameters evaluated except for creatinine, which was higher for the groups supplemented with arginine.

Protein arginine methyltransferase 6 is a novel substrate of protein arginine methyltransferase 1

BACKGROUND Post-translational modifications play key roles in various biological processes.Protein arginine methyltransferases(PRMTs)transfer the methyl group to specific arginine residues.Both PRMT1 and PRMT6 have emerges as crucial factors in the development and progression of multiple cancer types.We posit that PRMT1 and PRMT6 might interplay directly or in-directly in multiple ways accounting for shared disease phenotypes.AIM To investigate the mechanism of the interaction between PRMT1 and PRMT6.METHODS Gel electrophoresis autoradiography was performed to test the methyltranferase activity of PRMTs and characterize the kinetics parameters of PRMTs.Liquid chromatography-tandem mass spectrometryanalysis was performed to detect the PRMT6 methylation sites.RESULTS In this study we investigated the interaction between PRMT1 and PRMT6,and PRMT6 was shown to be a novel substrate of PRMT1.We identified specific arginine residues of PRMT6 that are methylated by PRMT1,with R106 being the major methylation site.Combined biochemical and cellular data showed that PRMT1 downregulates the enzymatic activity of PRMT6 in histone H3 methylation.CONCLUSION PRMT6 is methylated by PRMT1 and R106 is a major methylation site induced by PRMT1.PRMT1 methylation suppresses the activity of PRMT6.

Jugular arginine supplementation increases lactation performance and nitrogen utilization efficiency in lactating dairy cows

Background: Enhancing the post-ruminal supply of arginine(Arg), a semi-essential amino acid(AA), elicits positive effects on milk production. Our objective was to determine the effects of Arg infusion on milk production parameters and aspects of nitrogen(N) absorption and utilization in lactating dairy cows. Six lactating Chinese Holstein cows of similar body weight(508 ± 14 kg), body condition score(3.0 ± 0), parity(4.0 ± 0), milk yield(30.6 ±1.8 kg) and days in milk(20 ± 2 d) were randomly assigned to 3 treatments in a replicated 3 × 3 Latin square design with 21 d for each period(1 week for infusion and 2 weeks for washout). Treatments were 1) Control: saline;2) Arg group: saline + 9.42 g/L L-Arg;3) Alanine(Ala) group: saline + 19.31 g/L L-Ala(iso-nitrogenous to the Arg group). Milk production and composition, dry matter intake, apparent absorption of N, profiles of amino acids(AA) in blood,urea N in urine, milk, and blood, and gene expression of AA transporters were determined.Results: Compared with the Control or Ala group, the infusion of Arg led to greater expression of AA transporters(SLC7 A2 and SLC7 A8) and apparent uptake of free AA in the mammary gland, and was accompanied by greater milk yield, milk protein yield and milk efficiency(calculated by dividing milk yield over feed intake), together with lower concentration of urea N [regarded as an indicator of N utilization efficiency(NUE)] in blood and milk. Furthermore, in the cows infused with Arg, the NUE was higher and the concentration of urea N in urine was lower than those in the Ala group, although no differences were detected in NUE and urea N in urine between the Control and Arg group.The infusion of Ala had no effect on those indices compared with the Control.Conclusions: Overall, enhancing the post-ruminal supply of Arg via the jugular vein had a positive effect on the synthesis of milk protein at least in part by increasing gene expression of some AA transporters and uptake of free AA by mammary gland.

Nodulin 26-like intrinsic protein Cs NIP2;2 is a silicon influx transporter in Cucumis sativus L.

Nodulin 26-like intrinsic proteins(NIPs) are a family of channel-forming transmembrane proteins that function in the transport of water and other small molecules.Some NIPs can mediate silicon transport across plasma membranes and lead to silicon accumulation in plants,which is beneficial for the growth and development of plants.Cucumber is one of the most widely consumed vegetables;however,the functions of NIPs in this crop are still largely unknown.Here,we report the functional characteristics of Cs NIP2;2.It was found that Cs NIP2;2 is a tandem repeat of Cs NIP2;1,which had been demonstrated to be a silicon influx transporter gene.Cs NIP2;2 has a selectivity filter composed of cysteine,serine,glycine and arginine(CSGR),which is different from all previously characterized silicon influx transporters in higher plants at the second helix position.Xenopus laevis oocytes injected with Cs NIP2;2 c RNA demonstrated a higher uptake of silicon than the control,and the uptake remained unchanged under low temperature.Cs NIP2;2 was found to be expressed in the root,stem,lamina and petiole,and exogenous silicon treatment decreased its expression in the stem but not in other tissues.Transient expression of Cs NIP2;2-e GFP fusion sequence in onion epidermal cells showed that Cs NIP2;2 was localized to the cell nucleus,plasma membrane and an unknown structure inside the cell.The results suggest that Cs NIP2;2 is a silicon influx transporter in cucumber,and its subcellular localization and the selectivity filter are different from those of the previously characterized silicon influx transporters in other plants.These findings may be helpful for understanding the functions of NIPs in cucumber plants.

PRMT5和CDKN2B在宫颈癌组织的表达及临床意义

目的研究蛋白精氨酸甲基转移酶5(PRMT5)、细胞周期蛋白依赖性激酶抑制剂2B(CDKN2B)在宫颈癌中的表达及临床意义。方法收集2019年3月—2020年3月南京大学医学院附属鼓楼医院妇产科诊治宫颈癌患者88例。免疫组织化学法检测宫颈癌和癌旁组织中PRMT5、CDKN2B表达;采用Spearman相关分析PRMT5与CDKN2B表达的相关性;比较不同临床特征宫颈癌癌组织中PRMT5、CDKN2B表达的差异;Kaplan-Meier曲线评估PRMT5、CDKN2B表达对宫颈癌患者无进展生存预后的影响;多因素Cox回归分析宫颈癌患者无进展生存预后的影响因素。结果癌组织中PRMT5蛋白阳性率70.45%(62/88),高于癌旁组织6.82%(6/88)(χ^(2)=75.155,P<0.001)。宫颈癌组织中CDKN2B阳性率22.73%(20/88),低于癌旁组织79.55%(71/88)(χ^(2)=75.336,P<0.001)。宫颈癌中PRMT5与CDKN2B呈负相关(r=-0.734,P<0.001)。FIGOⅠB2~ⅡA期、有淋巴结转移宫颈癌组织中PRMT5阳性率高于FIGOⅠA~ⅠB1期、无淋巴结转移者,而CDKN2B阳性率则降低(χ^(2)/P=6.359/0.012、4.606/0.032、5.205/0.023、3.893/0.048)。PRMT5阳性组3年累积无进展生存率74.19%(46/62),低于PRMT5阴性组92.31%(24/26)(Log-Rankχ^(2)=4.386,P=0.017)。CDKN2B阴性组3年累积无进展生存率75.00%(51/68),低于CDKN2B阳性组95.00%(19/20)(Log-Rankχ^(2)=4.423,P=0.012)。FIGO分期ⅠB2~ⅡA期、合并淋巴结转移、PRMT5阳性、CDKN2B阴性是影响宫颈癌患者无进展生存预后的独立危险因素[OR(95%CI)=1.407(1.159~1.696),1.464(1.201~1.784),1.614(1.189~2.192),1.595(1.191~2.136)]。结论宫颈癌组织中PRMT5表达升高,CDKN2B表达降低,两者与宫颈癌患者的不良临床病理特征有关,是评估宫颈癌预后的标志物。

基于同位素标记的相对和绝对定量技术筛选双孢蘑菇采后开伞相关差异蛋白

目的筛选双孢蘑菇采后开伞相关差异蛋白,探究双孢蘑菇采后开伞的分子机制。方法选用贮藏前(0d)和刚破膜开伞(6d)的双孢蘑菇子实体为实验材料,通过同位素标记的相对和绝对定量(isobaric tags for relative and absolute quantitation,iTRAQ)蛋白质组学技术筛选与双孢蘑菇采后破膜开伞相关的差异表达蛋白,并通过GO分析、KEGG通路富集分析等生物信息学手段对差异表达蛋白进行分析鉴定。结果贮藏0 d和6 d的两组双孢蘑菇样品中共鉴定到差异表达蛋白808个,包括285个上调蛋白和523个下调蛋白。与基因组数据库比对发现,筛选到的差异蛋白仅有38个被注释,且注释蛋白主要与精氨酸代谢、核酸代谢、糖代谢和氧化反应等生物学过程密切相关。GO功能和KEGG通路富集显示开伞相关差异蛋白主要富集在质膜细胞结构中,参与氰基氨基酸代谢、苯丙烷生物合成、糖代谢、精氨酸与脯氨酸代谢等途径。结论差异蛋白涉及的信号途径和代谢过程,特别是精氨酸代谢过程,在双孢蘑菇采后开伞过程发挥重要的调控作用。

蛋白精氨酸甲基转移酶5表达与非M3型急性髓系白血病疗效关系的临床观察

目的讨论蛋白精氨酸甲基转移酶5(PRMT5)与急性髓系白血病(AML)患者低甲基化药物(HMA)治疗敏感性的关系。方法通过GEPIA和TCGA数据库分析AML患者PRMT5表达及其与AML患者生存的关系。收集2020年1月至2023年10月收治的81例AML患者,包括50例非M3型患者和31例M3型患者。采用实时荧光定量PCR(qPCR)检测骨髓样本中PRMT5表达。采用全基因组重亚硫酸盐测序(WGBS)检测基因组甲基化水平。结果TCGA数据库中AML患者PRMT5表达显著高于健康对照人群(P<0.01);PRMT5高表达组患者总生存期更短(P=0.036)。进一步分析TCGA数据库,巩固期给予HMA后,PRMT5表达对无事件生存率(EFS)和OS的有明显影响(P<0.010)。81例新诊断AML患者PRMT5表达显著高于23例健康志愿者[3.25(1.69,5.16)vs.1.00(0.72,1.35),P<0.001]。非M3型AML患者PRMT5表达高于M3型患者[4.51(2.05,7.25)vs.2.01(1.53,3.35),(P<0.001)]。在非M3型AML患者中,PRMT5高表达与BM原始细胞百分率以及不良基因突变和高危患者比例更高有关(P<0.05)。与未接受HMA治疗患者比较,接受HMA治疗的PRMT5高表达非M3型AML患者CR率显著增加(P=0.003)。通过WGBS测序,PRMT5高表达组CpG岛甲基化比率以及转录起始位点、转录终止位点CpG岛甲基化比率高于PRMT5低表达组(P<0.001)。结论在非M3型AML患者中PRMT5高表达,PRMT5高表达预示着更多非M3型AML患者从HMA治疗中获益。PRMT5可能是评估肿瘤甲基化富集和预测疾病预后的潜在生物标志物。

精氨酸甲基转移酶在肝细胞癌中作用的研究进展

肝细胞癌是一种异质性疾病,其发生的复杂性与表观遗传修饰有关。哺乳动物蛋白质精氨酸甲基转移酶(protein arginine methyltransferases,PRMTs)可介导细胞的表观遗传修饰,并在肝细胞癌的发生、发展、治疗及预后中发挥重要作用。PRMTs催化组蛋白和非组蛋白靶蛋白的精氨酸残基发生单甲基化和(对称的及不对称的)二甲基化。PRMT1、2、3、4、5、6、7、9等家族成员在肝细胞癌中的作用不同,涉及癌细胞生长、转移、治疗和预后等。选择性和特异性PRMTs抑制剂的研究开发有望为临床肝细胞癌的治疗和预后提供新思路和新靶点。本文重点概述PRMTs在肝细胞癌中作用的机制研究进展。

低蛋白饲料添加亮氨酸、精氨酸对大菱鲆幼鱼生长、消化、免疫及mTOR信号通路的影响

为探究亮氨酸和精氨酸作为信号分子参与调控mTOR信号通路对大菱鲆(Scophthalmus maximus)生长的作用,本研究以大菱鲆幼鱼(初始体质量(13.50±0.19)g)为实验对象,设置50%蛋白水平饲料作为阳性对照组,45%蛋白水平饲料作为阴性对照组,设置两个实验组,分别为在阴性对照组中添加1%亮氨酸的实验组和添加1%精氨酸的实验组,饲养周期为56 d,测量大菱鲆的生长性能和饲料利用水平。研究表明,添加亮氨酸、精氨酸均能一定程度提高因饲料蛋白水平不足导致的大菱鲆的特定生长率、蛋白质效率和增重率下降。添加1%亮氨酸和1%精氨酸均能在摄食后有效增强大菱鲆肌肉与肝脏mTOR信号通路中的雷帕霉素靶蛋白(mTOR)、核糖体蛋白S6和真核起始因子4E结合蛋白1(4E-BP1)的磷酸化。添加1%精氨酸还能够提高大菱鲆肠道淀粉酶和脂肪酶活性,显著提高血清过氧化氢酶和溶菌酶水平并增加血清总抗氧化能力。研究结果表明,在低蛋白饲料中添加1%亮氨酸、1%精氨酸能够激活大菱鲆mTOR信号通路,有效提高其生长性能和蛋白质效率;此外,添加1%精氨酸还能够提高大菱鲆的消化酶活性、增强非特异性免疫反应。

拟穴青蟹精氨酸激酶的重组表达及致敏性分析

为比较拟穴青蟹(Scylla paramamosain)重组精氨酸激酶(recombinant arginine kinase,rAK)和天然AK(native AK,nAK)的致敏性,并鉴定AK分子中的致敏优势区域,首先基于AK的抗原表位分布与空间结构,将AK分子分为AK-E1(氨基酸(amino acids,AA)1~92)、AK-E2(AA 87~187)、AK-E3(AA 172~265)和AK-E4(AA 276~357)4个片段,采用大肠杆菌原核表达系统对其进行分段表达,并分别分离纯化nAK、rAK及AK的4个分段表达产物。用BALB/c小鼠模型评价重组蛋白的致敏性,结果显示,rAK致敏小鼠血清中特异性抗体水平、脾脏淋巴细胞的Th2型细胞因子释放水平均显著升高,表明rAK可使机体致敏,但其免疫原性较nAK弱;AK的4个分段表达产物中AK-E2的免疫原性最强。同时,rAK能够刺激RBL-2H3细胞释放β-己糖苷酶,但rAK对效应细胞的刺激作用低于nAK;4个分段表达产物中AK-E2和AK-E4对效应细胞的刺激作用较强。综上,通过原核表达系统获得的rAK免疫原性较nAK弱,而AK分子中免疫原性较强的区域为AA 87~187,免疫反应性较强的区域为AA 276~357。

OsPRMT6a-mediated arginine methylation of OsJAZ1 regulates jasmonate signaling and spikelet development in rice

Although both protein arginine methylation(PRMT)and jasmonate(JA)signaling are crucial for regulating plant development,the relationship between these processes in the control of spikelet development remains unclear.In this study,we used the CRISPR/Cas9 technology to generate two OsPRMT6a loss-of-function mutants that exhibit various abnormal spikelet structures.Interestingly,we found that OsPRMT6a can methylate arginine residues in JA signal repressors OsJAZ1 and OsJAZ7.We showed that arginine methylation of OsJAZ1 enhances the binding affinity of OsJAZ1 with the JA receptors OsCOI1a and OsCOI1b in the presence of JAs,thereby promoting the ubiquitination of OsJAZ1 by the SCF^(OsCOI1a/OsCOI1b) complex and degradation via the 26S proteasome.This process ultimately releases OsMYC2,a core transcriptional regulator in the JA signaling pathway,to activate or repress JA-responsive genes,thereby maintaining normal plant(spikelet)development.However,in the osprmt6a-1 mutant,reduced arginine methylation of OsJAZ1 impaires the interaction between OsJAZ1 and OsCOI1a/OsCOI1b in the presence of JAs.As a result,OsJAZ1 proteins become more stable,repressing JA responses,thus causing the formation of abnormal spikelet structures.Moreover,we discovered that JA signaling reduces the OsPRMT6a mRNA level in an OsMYC2-dependent manner,thereby establishing a negative feedback loop to balance JA signaling.We further found that OsPRMT6a-mediated arginine methylation of OsJAZ1 likely serves as a switch to tune JA signaling to maintain normal spikelet development under harsh environmental conditions such as high temperatures.Collectively,our study establishes a direct molecular link between arginine methylation and JA signaling in rice.

精氨酸/低酯果胶对乳液热稳定性的影响

针对油脂蛋白多糖多重乳液体系在热力杀菌过程中因发生乳清蛋白变性团聚而引起的乳液不稳定现象,通过精氨酸(Arg)和低酯果胶(LMP)对蛋白胶束表面电荷和胶束结构的修饰作用,形成相应的精氨酸乳清蛋白复合物(Arg-whey protein complex,AWPC)和精氨酸乳清蛋白低酯果胶复合物(Arg-whey protein-low methoxyl pectin complex,AWPPC)。研究结果表明:通过Arg复合修饰、热力杀菌(121℃,15 min)后油脂蛋白多糖多重乳液体系的平均粒径减小39.1%,Zeta电位绝对值增加17.6%,乳化活性指数(EAI)提高18.7%,冻融和杀菌处理的冷热稳定性显著提高。当Arg和LMP的最佳质量比为0.15∶0.70时,AWPPC溶液的EAI达到最大值6.10 m 2/g。

精氨酸对豹纹鳃棘鲈肠道发育和饲料蛋白质利用效率的影响

为研究饲料中添加不同水平精氨酸对豹纹鳃棘鲈(Plectropomus leopardus)幼鱼[初始体重(9.30±0.02)g]生长性能、体成分、肠道和肝脏组织发育的影响,在基础饲料中,分别制作精氨酸水平为2.4%(Arg2.4,对照组),2.9%(Arg2.9组),3.4%(Arg3.4组),3.9%(Arg3.9组)和4.4%(Arg4.4组)5组等氮等脂(54%粗蛋白质,9%粗脂肪)饲料。投喂豹纹鳃棘鲈幼鱼试验饲料56 d后,Arg3.4、Arg3.9和Arg4.4组蛋白质效率和蛋白质沉积率分别较Arg2.4组提高9.88%、7.41%、5.56%和17.33%、12.68%、11.99%(P<0.05)。Arg3.4、Arg3.9和Arg4.4组增重率分别较Arg2.4组提高32.03%、20.26%、17.48%(P<0.05)。相较于Arg2.4组,Arg2.9和Arg3.4组粗蛋白质含量分别提高1.62%、1.87%(P<0.05)。饲料精氨酸水平对各组鱼体水分含量、肌肉中风味氨基酸的总量均无显著影响(P>0.05)。相较于Arg2.4组,Arg3.4和Arg3.9组肥满度分别提高8.70%、8.21%(P<0.05)。精氨酸对各组间肝体比、脏体比、肝脏空泡化面积、肠道绒毛宽度和肠壁厚度均无显著影响(P>0.05)。Arg2.9、Arg3.4和Arg3.9组肠道绒毛长度和隐窝深度分别较Arg2.4组提高16.33%、20.13%、17.66%和124.36%、138.09%、110.43%(P<0.05)。基于蛋白质效率进行二元拟合后获得豹纹鳃棘鲈幼鱼饲料精氨酸适宜水平为3.52%。综上所述,精氨酸可以改善肠道组织发育,有效地促进鱼体对饲料蛋白质的利用。

补喂大豆浓缩蛋白、精氨酸+赖氨酸对哺乳期羔羊生长和生长轴激素水平的影响

为研究补喂大豆浓缩蛋白(SPC)、精氨酸+赖氨酸(Arg+Lys)对哺乳期羔羊生长和生长轴激素水平的影响,试验选用平均体重为(6.02±0.45)kg的7日龄双胎湖羊羔羊24只,随机分为3组,每组8只羊(4公4母),分别为对照组、SPC组和AA组。对照组补喂生理盐水、SPC组补喂250 mg/kg BW大豆浓缩蛋白、AA组补喂50 mg/kg BW Arg+50 mg/kg BW Lys,试验期28 d。结果表明:(1)与对照组相比,SPC组羔羊35 d体重、7~35 d平均日增重提高了10.62%、23.25%(P> 0.05),AA组羔羊35 d体重、7~35 d平均日增重显著提高了21.06%、47.16%(P <0.05)。(2)与对照组相比,SPC组和AA组羔羊血浆谷氨酰胺浓度显著降低了17.65%、20.19%(P <0.05);AA组羔羊补喂前0 h血浆尿素氮浓度显著提高了46.48%(P <0.05),SPC组与AA组羔羊补喂后1.5 h血浆尿素氮浓度显著提高了24.46%、22.86%(P <0.05)。(3)与对照组相比,SPC组羔羊补喂后1 h血浆生长抑素(SS)提高了16.30%(P>0.05),AA组羔羊显著提高了21.84%(P <0.05);SPC组和AA组羔羊补喂后2 h血浆生长激素(GH)显著提高了9.98%、11.89%(P <0.05);AA组羔羊补喂前0 h血浆胰岛素样生长因子-I (IGF-I)显著提高了6.96%(P <0.05);SPC组羔羊补喂后2 h血浆葡萄糖显著降低了18.20%(P <0.05)。由此可见,补喂250 mg/kg BW的SPC、50 mg/kg Arg+50 mg/kg Lys可提高血浆GH、IGF-I水平,提高哺乳期羔羊增重。