Natural variation in the cytochrome c oxidase subunit 5B OsCOX5B regulates seed vigor by altering energy production in rice

Seed vigor is a crucial trait for the direct seeding of rice.Here we examined the genetic regulation of seed vigor traits in rice,including germination index(GI)and germination potential(GP),using a genome-wide association study approach.One major quantitative trait locus,qGI6/qGP6,was identified simultaneously for both GI and GP.The candidate gene encoding the cytochrome c oxidase subunit 5B(OsCOX5B)was validated for qGI6/qGP6.The disruption of OsCOX5B caused the vigor traits to be significantly lower in Oscox5b mutants than in the japonica Nipponbare wild type(WT).Gene co-expression analysis revealed that OsCOX5B influences seed vigor mainly by modulating the tricarboxylic acid cycle process.The glucose levels were significantly higher while the pyruvic acid and adenosine triphosphate levels were significantly lower in Oscox5b mutants than in WT during seed germination.The elite haplotype of OsCOX5B facilitates seed vigor by increasing its expression during seed germination.Thus,we propose that OsCOX5B is a potential target for the breeding of rice varieties with enhanced seed vigor for direct seeding.

The role of polymorphic cytochrome P450 gene(CYP2B6)in B-chronic lymphocytic leukemia(B-CLL)incidence and outcome among Egyptian patients

Cytochromes P450(CYPs)play a prominent role in catalyzing phase I xenobiotic biotransformation and account for about 75%of the total metabolism of commercially available drugs,including chemotherapeutics.The gene expression and enzyme activity of CYPs are variable between individuals,which subsequently leads to different patterns of susceptibility to carcinogenesis by genotoxic xenobiotics,as well as differences in the efficacy and toxicity of clinically used drugs.This research aimed to examine the presence of the CYP2B6*9 polymorphism and its possible association with the incidence of B-CLL in Egyptian patients,as well as the clinical outcome after receiving cyclophosphamide chemotherapy.DNA was isolated from whole blood samples of 100 de novo B-CLL cases and also from 100 sex-and age-matched healthy individuals.The presence of the CYP2B6*9(G516T)polymorphism was examined by PCR-based allele specific amplification(ASA).Patients were further indicated for receiving chemotherapy,and then they were followed up.The CYP2B6*9 variant indicated a statistically significant higher risk of B-CLL under different genetic models,comprising allelic(T-allele vs.G-allele,OR=4.8,p<0.001)and dominant(GT+TT vs.GG,OR=5.4,p<0.001)models.Following cyclophosphamide chemotherapy,we found that the patients with variant genotypes(GT+TT)were less likely to achieve remission compared to those with the wild-type genotype(GG),with a response percentage of(37.5%vs.83%,respectively).In conclusion,our findings showed that the CYP2B6*9(G516T)polymorphism is associated with B-CLL susceptibility among Egyptian patients.This variant greatly affected the clinical outcome and can serve as a good therapeutic marker in predicting response to cyclophosphamide treatment.

白藜芦醇通过ERK1/2和NF-κB通路调节NADPH氧化酶表达改善急性肺损伤

目的探讨白藜芦醇对急性肺损伤大鼠NADPH氧化酶的影响,并分析相关信号通路机制。方法将50只雄性SPF级SD大鼠随机分为对照组、模型组、地塞米松组、低剂量白藜芦醇组和高剂量白藜芦醇组,每组10只。对照组和模型组给予生理盐水干预,地塞米松组、低剂量白藜芦醇组和高剂量白藜芦醇组分别给予2 mg/kg地塞米松、100 mg/kg白藜芦醇、500 mg/kg白藜芦醇干预,1次/d,连续干预14 d。干预结束后,除对照组外,其余组别大鼠构建急性肺损伤模型。比较各组大鼠肺组织病理状态、肺湿重/干重比(W/D)、肺损伤评分,采用ELISA法检测肺泡灌洗液白细胞介素-6(IL-6)、白细胞介素-8(IL-8)、肿瘤坏死因子-α(TNF-α)水平;试剂盒检测丙二醛(MDA)、超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)水平;采用RT-PCR法检测各组NADPH氧化酶亚基p47^(phox)、p22^(phox),及ERK、NF-κB mRNA水平;采用Western bloting法检测各组p47^(phox)、p22^(phox)、p-ERK1/2、ERK1/2、p-NF-κB、NF-κB蛋白水平。结果模型组、地塞米松组、低剂量白藜芦醇组和高剂量白藜芦醇组W/D及肺损伤评分、MDA水平、p22^(phox)、p47^(phox)、ERK1/2、NF-κB mRNA、p47^(phox)蛋白、p-ERK/ERK、p-NF-κB/NF-κB、IL-6、IL-8、TNF-α水平高于对照组,而SOD、GSH-Px水平低于对照组(P<0.05)。结论白藜芦醇可改善LPS诱导的急性肺损伤大鼠NADPH氧化酶及氧化应激状态,其作用机制可能与ERK1/2-NF-κB通路有关。

川芎嗪对脑缺血再灌注小鼠脑损伤及NADPH氧化酶表达的影响

目的研究川芎嗪对脑缺血再灌注小鼠大脑氧化应激损伤的保护作用和还原型烟酰胺腺嘌呤二核苷酸磷酸(nicotinamide adenine dinucleotide phosphate,NADPH)氧化酶表达的影响。方法采用线栓法建立大脑中动脉闭塞/再灌注模型。造模后对小鼠进行Longa神经功能评分;采用HE和氯化三苯基四氮唑染色法(triphenyltetrazolium chloride staining,TTC)分别观察脑组织的病理改变和梗死情况;检测脑组织中超氧化物歧化酶(total antioxidative capacity,T-AOC)、过氧化物酶(superoxide dismutase,SOD)、乳酸脱氢酶(malondialdehyde,MDA)、过氧化氢(hydrogen peroxide,H_(2)O_(2))和髓过氧化物酶(myeloperoxidase,MPO)的变化,Western blot检测NADPH氧化酶活化蛋白p47抗体(NADPH oxidase activated protein p47 antibody,P47phox)和NADPH氧化酶(NADPH oxidase,Nox)4蛋白的表达,免疫组化检测肿瘤坏死因子(tumor necrosis factor,TNF)-α的表达。结果川芎嗪能显著减轻脑缺血再灌注小鼠的脑组织损伤、缩小脑梗死体积,升高脑缺血再灌注小鼠脑组织中T-AOC、SOD水平而降低MDA、H_(2)O_(2)和MPO的含量(P<0.05),同时降低其脑组织中P47phox、Nox4和TNF-α的蛋白表达(P<0.05)。结论川芎嗪对脑缺血再灌注小鼠大脑损伤具有明显的保护作用,其机制与降低NADPH氧化酶的表达进而抑制氧化应激及减轻炎症反应有关。

NADPH氧化酶4在心血管损伤中的作用机制

心血管结构和功能损伤是许多心血管疾病的重要病理基础,许多研究表明氧化应激在缺血性心脏病、动脉粥样硬化、高血压等诸多病理性心血管损伤中发挥重要作用。NADPH氧化酶(Nox)是调控氧化还原信号的关键酶,而血管内的活性氧主要来源于Nox4。随着研究的不断深入,发现Nox4在不同阶段或不同刺激下会发挥不同甚至截然相反的作用,如双向调节动脉粥样硬化的进展、双向作用影响血压等。现总结Nox4在不同心血管损伤中的不同影响及作用机制,为后续的研究提供一定的理论基础。

NADPH oxidase 4(NOX4)as a biomarker and therapeutic target in neurodegenerative diseases

Diseases like Alzheimer’s and Parkinson’s diseases are defined by inflammation and the damage neurons undergo due to oxidative stress. A primary reactive oxygen species contributor in the central nervous system, NADPH oxidase 4, is viewed as a potential therapeutic touchstone and indicative marker for these ailments. This in-depth review brings to light distinct features of NADPH oxidase 4, responsible for generating superoxide and hydrogen peroxide, emphasizing its pivotal role in activating glial cells, inciting inflammation, and disturbing neuronal functions. Significantly, malfunctioning astrocytes, forming the majority in the central nervous system, play a part in advancing neurodegenerative diseases, due to their reactive oxygen species and inflammatory factor secretion. Our study reveals that aiming at NADPH oxidase 4 within astrocytes could be a viable treatment pathway to reduce oxidative damage and halt neurodegenerative processes. Adjusting NADPH oxidase 4 activity might influence the neuroinflammatory cytokine levels, including myeloperoxidase and osteopontin, offering better prospects for conditions like Alzheimer’s disease and Parkinson’s disease. This review sheds light on the role of NADPH oxidase 4 in neural degeneration, emphasizing its drug target potential, and paving the path for novel treatment approaches to combat these severe conditions.

NADPH氧化酶4在1型糖尿病模型小鼠角膜病变中的致病作用及其机制

目的探讨还原型烟酰胺腺嘌呤二核苷酸氧化酶4(Nox4)在1型DM模型小鼠角膜病变中的致病作用及其可能机制。方法选择Nox4基因敲除(Nox4^(-/-))纯合子雄性小鼠40只,以鼠龄、性别匹配的野生型C57BL/6(Nox4^(+/+))小鼠120只作为对照。采用随机数字表法分别将2种小鼠随机分为DM组和非DM组,DM组小鼠采用链脲佐菌素腹腔内注射法构建1型DM模型。采用随机数字表法分别将Nox4^(+/+)小鼠DM组和非DM组分为普通饲料喂养小鼠和添加Nox4抑制剂GKT137831(GKT)饲料喂养小鼠。于DM造模后第16周采用酚红棉线法检测各组小鼠泪液分泌量;采用荧光素钠染色评分法评估角膜上皮完整性;采用激光扫描共聚焦显微镜观察角膜基质层神经纤维密度变化;采用CellROX荧光探针检测角膜上皮中活性氧簇(ROS)含量;采用免疫荧光染色法检测小鼠角膜上皮中E-Cadherin蛋白和核因子-κB(NF-κB)蛋白表达变化;采用角膜铺片TUBB3染色法检测角膜中央区神经纤维密度。结果Nox4^(+/+)小鼠DM组和非DM组泪液分泌量分别为(2.40±1.18)和(5.30±1.02)mm/min,差异有统计学意义(P<0.01);Nox4^(-/-)小鼠DM组泪液分泌量为(4.19±0.63)mm/min,明显多于Nox4^(+/+)小鼠DM组,差异有统计学意义(P<0.05);普通饲料喂养小鼠与GKT添加饲料喂养小鼠DM组泪液分泌量分别为(2.23±0.83)和(4.02±0.71)mm/min,差异有统计学意义(P<0.01)。与Nox4^(+/+)小鼠非DM组比较,Nox4^(+/+)小鼠DM组角膜荧光素染色评分显著升高,角膜神经纤维密度显著降低,角膜上皮中ROS荧光强度明显增强,E-Cadherin蛋白表达荧光强度减弱,NF-κB蛋白表达荧光强度增强。Nox4^(-/-)或GKT添加饲料喂养小鼠DM组与非DM组比较角膜上皮中ROS荧光增强,E-Cadherin蛋白表达荧光减弱。Nox4^(-/-)和GKT添加饲料喂养小鼠DM组角膜上皮细胞中NF-κB蛋白荧光强度均较弱,与非DM组强度一致。角膜铺片免疫荧光染色显示,Nox4^(+/+)小鼠DM组中TUBB3染色的神经纤维密度明显低于非DM组,Nox4^(-/-)或GKT添加饲料喂养小鼠DM组角膜基质层神经纤维与非DM组比较无明显减少。结论Nox4参与了糖尿病角膜病变的致病过程,其机制可能与氧化应激诱导ROS产物聚集,激活NF-κB介导的炎症反应有关。

Creation of cytochrome P450 catalysis depending on a non-natural cofactor for fatty acid hydroxylation

Cytochrome P450 enzymes catalyze diverse oxidative transformations at the expense of reduced nicotinamide adenine dinucleotide phosphate(NADPH),however,their applications remain limited largely because NADPH is cost-prohibitive for biocatalysis at scale yet tightly regulated in host cells.A highly challenging task for P450 catalysis has been to develop an alternative and biocompatible electrondonating system.Here we engineered P450 BM3 to favor reduced nicotinamide cytosine dinucleotide(NCDH)and created non-natural cofactor-dependent P450 catalysis.Two outstanding mutants were identified with over 640-fold NCDH preference improvement and good catalytic efficiencies of over15,000 M^(-1)s^(-1)for the oxidation of the fatty acid probe 12-(para-nitrophenoxy)-dodecanoate.Molecular docking analysis indicated that these mutants bear a compacted cofactor entrance.Upon fusing with an NCD-dependent formate dehydrogenase,fused proteins functioned as NCDH-specific P450catalysts by using formate as the electron donor.Importantly,these mutants and fusions catalyzed NCDH-dependent hydroxylation of fatty acids with similar chain length preference to those by natural P450 BM3 in the presence of NADPH and also similar regioselectivity for subterminal hydroxylation of lauric acid.As P450 BM3 and its variants are catalytically powerful to take diverse substrates and convey different reaction paths,our results offer an exciting opportunity to devise advanced cell factories that convey oxidative biocatalysis with an orthogonal reducing power supply system.

NADPH氧化酶对ROS和铁死亡在骨稳态作用中的研究进展

NADPH氧化酶(NADPH Oxidase,NOXs)是产生超氧化物的酶,在机体防御、生物合成途径以及细胞信号传导中发挥作用。NOXs作为活性氧(ROS)的主要来源,已成为抗氧化应激、炎症、纤维化和肿瘤的热门靶点。文献提示,NOXs及其相关的氧化还原反应与破骨细胞和成骨细胞密切相关,它驱动膜相关活性氧(reactive oxygen species,ROS)及启动铁死亡,影响骨形成和骨吸收。本文拟综述NOXs对ROS和铁死亡在骨稳态中的作用为NOXs治疗骨代谢相关疾病提供文献参考。

基于深度学习的NADPH为碳反应提供能量的探究

本文对还原型辅酶的类型与作用进行了介绍,NADPH本质是一种辅酶--还原型辅酶Ⅱ,在动植物细胞中有多种来源,可与NADH和ATP相互转化,也可转移到细胞的其他部位。NADPH的作用多种多样,其在多种疾病中发挥的作用,将为人类健康及新型药物的研究提供新思路。

利用不同方法将小分子NADPH转染进入细胞的比较

目的利用非代谢途径直接将外源小分子烟酰胺腺嘌呤二核苷酸磷酸(NADPH)转染进入细胞内的方法。方法对比3种不同转染试剂(X-tremeGENE TM HP DNA、Lipofectamine TM RNAiMAX和Lipofectamine TM 2000)将NADPH转染到人骨肉瘤细胞系U2OS和小鼠胚胎成纤维细胞系3T3L1中的效果,并通过油红O染色比较它们对脂肪细胞分化的影响。结果用X-tremeGENE HP DNA转染试剂转染NADPH可以有效提高细胞内NADPH水平(P<0.001)。随着NADPH转染浓度(10μmol/L NADPH与10μL转染试剂)的增加,细胞中的NADPH水平呈剂量依赖性增加。此外使用3种转染试剂在3T3L1前脂肪细胞中转染NADPH,只有使用X-tremeGENE HP DNA转染试剂转染NADPH的脂肪细胞分化更明显(P<0.001)。结论X-tremeGENE HP DNA转染试剂能够成功地将外源NADPH转染进入细胞内,并促进3T3L1脂肪细胞的分化和脂质积累。

Method for Detecting NADPH-Cytochrome P450 Reductase in Liver Microsomal Fractions by Using Native Polyacrylamide Gel Electrophoresis and NADPH-Diaphorase Staining

By combining native polyacrylamide gel electrophoresis (PAGE) and nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase staining, a simple method for detecting NADPH-cytochrome P450 reductase in tissue samples was established. When rat liver microsomal fractions were examined by this method, several bands with different mobility were visualized. Western blot analysis indicated that the band which appeared in the most anodal position among them represented NADPH-cytochrome P450 reductase. SDS-PAGE/Western blot analysis revealed that the molecular weight of the protein forming the band was around 80 kDa, which was identical to that of rat NADPH-cytochrome P450 reductase. The intensity level of NADPH-diaphorase staining assigned to this enzyme estimated by this method increased four times in microsomal fractions prepared from rat fed ethanol chronically compared to that from controls. When a dilution series of a rat liver microsomal fraction was examined by this method and SDS-PAGE/Western blot analysis, their staining intensities representing this enzyme were significantly correlated with each other. Using the naive PAGE/NADPH-diaphorase staining method, NADPH-cytochrome P450 reductase is detected in rat liver microsomes. This method is beneficial because compared with the conventional SDS-PAGE/Western blot analysis, the quantification of NADPH-cytochrome P450 reductase in tissue samples is allowed to be more easily done.

Cytochrome C在大鼠SAH后早期脑损伤的表达及意义

目的:本实验采用枕大池注血法建立大鼠蛛网膜下腔出血动物模型,通过研究细胞色素C(Cytochrome C)在动物体内和体外表达变化,探讨c-Jun氨基末端激酶(JNK)信号传导通路是否参与了蛛网膜下腔出血(SAH)后早期脑损伤(EBI)的发生、发展,并进一步探讨JNK在EBI中的作用及意义。方法:随机选取120只大鼠采用枕大池注血法建立标准SAH动物模型。随机将其分为6组:分别为正常组(n=20),假手术组(Sham组,n=20),SAH组(n=20),SAH+DMSO(二甲基亚砜)组(n=20),SAH+SP600125(10mg/kg)组(n=20)和SAH+SP600125(30mg/kg)组(n=20)。利用TUNEL显色法检测大脑皮层区域细胞凋亡现象情况;运用Western Blotting法动态检测脑组织Cytochrome C蛋白表达情况。结果:(1)蛛网膜下腔出血后大鼠神经行为功能异常;Western Blot法检测大脑皮质Cytochrome C表达增加;蛛网膜下腔出血后24h,通过TUNEL检测大脑皮层区脑组织细胞的异常染色、结构紊乱等凋亡征象。(2)SP600125干预后,大鼠神经行为功能异常有所好转;检测大脑皮质Cytochrome C值减少,实验组大脑皮层细胞凋亡征象减少。结论:神经元细胞凋亡途径是蛛网膜下腔出血后早期脑损伤过程中重要的病理生理机制;JNK信号传导通路可能通过诱导细胞凋亡而促进早期脑损伤的发生、发展;SP600125可能通过抑制JNK信号传导通路中Cytochrome C蛋白表达从而保护蛛网膜下腔出血后造成的早期脑损伤。

NADPH氧化酶导致糖尿病肾病病理改变机制的研究进展

烟酰胺腺嘌呤二核苷酸磷酸(NADPH)氧化酶是引发糖尿病肾病病理改变的重要因素,通过氧化应激反应作用于肾脏。对NADPH氧化酶的研究成为近年热点。本文对NADPH氧化酶导致糖尿病肾病病理改变机制进行综述。

Phylogenetic Relationships and Status Quo of Colonies for Gayal Based on Analysis of Cytochrome b Gene Partial Sequences

Thirty-three mutations and four different haplotypes were found when cytochrome b（Cytb） gene partial sequences of 12 gayals were analyzed. Together with sequences of Bos indicus, Bos taurus, Bos grunniens, and Bos gaurus with Bubalus bubalis as the out group, the partial sequences of Cytb gene of gayals were aligned and base composition and nucleotide variation of Cytb gene were analyzed. The phylogenetic trees were constructed by the NJ method and the MP method respectively, both supporting almost the same topology. Gayal is an independent species of Bos from Bos indicus, Bos taurus, and Bos gaurus. The results also indicate that a great proportion of gayal bloodline was invaded by other species, and the protection of gayal is facing a formidable situation.

Phylogeny of Apaturinae Butterflies (Lepidoptera: Nymphalidae) Based on Mitochondrial Cytochrome OxidaseⅠ Gene

The phylogenetic relationships of genera in the subfamily Apaturinae were examined using mtDNA sequence data from 1,471 bp of cytochrome oxidase subunit Ⅰ （COI）. The mitochondrial COI gene from a total of 16 species in 11 genera were sequenced to obtain mtDNA data, along with those of 4 species obtained from GenBank, to construct the MP and the NJ trees using Athyma jina, Penthema adelma, Polyura nepenthes, and Charaxes bernardus as outgroups. The transitions at the third codon positions of the COI data set were found saturated, but they were retained for analysis, because they contain the majority of the phylogenetic information. The impacts of equal weight assumptions for all characters in the parsimonious analysis were assessed by potential alternations in clades in response to different transition/transversion weighting schemes. The results indicated four distinct major groups in Apaturinae. Moreover, several well supported and stable clades were found in the Apaturinae. The study also identified undetermined taxon groups whose positions were weakly supported and were subject to changes under different weighting schemes. Within the Apaturinae, the clustering results are approximately identical to the classical morphological classification. The mtDNA data suggest the genus Mimathyma as a monophyletic group. Lelecella limenitoides and Dilipa fenestra have close relationship with very strong support in all phylogenetic trees. It also supports the taxonomic revision of removing several species from Apatura to other genera, namely Mimathyma schrenckii, M. chevana, M. nycteis, Chitoria subcaerulea, C. fasciola, C. pallas, and Helcyra subalba.

The Phylogenetic Relationships among Four Subspecies of the Genus Locusta Based on Sequences of Three Subunit of Cytochrome Oxidase

[Objective] The aim was to explore the phylogenetic relationships among four subspecies of the genus Locusta.[Method] The sequences of three subunits of cytochrome oxidase of Locusta migratoria tibetensis and Locusta migratoria manilensis were amplified and sequenced（COⅠ 1 539 bp,COⅡ 684 bp,CO Ⅲ 792 bp,with the total of 3 015 bp）.The corresponding sequenses of Locusta migratoria migratoria and Locusta migratoria migratorioides were obtained from GenBank and constructed a multiple alignment.Phylogenic trees of four subspecies of L.migratoria were constructed by Neighbor-Joining,Maximum-parsimony and Bayesian,respectively.[Result] The average content of A ＋ T in three subunits of four subspecies was 69.57%;the third site of codon showed the highest A ＋ T content,and the COⅠ had the highest A ＋ T content（87.6%）;The nucleotide substitution mainly occurred at the third site of codon,and the nucleotide replacement rate of CO Ⅱ was the highest.The second site of codon was conservative,so the replacement rate was in the range of 5.9%-15%.The start codon of COⅠ was CCG or ACG.Genetic distances among four subspecies were ranged from 0.001 to 0.076.The relationship between L.m.tibetensis and Locusta migratoria manilensis was the closest,followed by L.m.migratorioides and L.m.migratorioides,while the genetic distance between L.m.tibetensis and L.m.migratorioides was the largest.[Conclusion] The phylogenetic relationships among four subspecies of Locusta migratoria is L.m.tibetensis,L.m.manilensis,L.m.migratoria,L.m.migratorioides.

Identification of sika deer and red deer using partial cytochrome b and 12s ribosomal RNA genes

A study was conducted on the identifications of the degraded samples of sika deer （Cervus nippon） and red deer （Cervus elaphus） by phylogenetic and nucleotide distance analysis of partial Cytb and 12s rRNA genes sequences. 402 bp Cytb genes were achieved by PCR-sequencing using DNA extracted from 8 case samples, and contrasted with 27 sequences of Cytb gene downloaded from GenBank database. The values of three nucleotide distance between three suspected samples and sika deer were identical （0.026±0.006）, which was smaller than the smallest nucleotide distance between eastern red deer and sika deer （0.036）. Furthermore, phylogenetic analysis of sika deer and red deer indicated that the evidences located within the same cluster as sika deer. The evidences were sika deer materials. As the same way, other three suspected samples were derived from red deer. The results were further confirmed by phylogenetic and nucleotide distance analysis of 387 bp 12s rRNA gene. The method was powerful and less time-consuming and helpful to reduce the related cases with wildlife.

Bioinformatics Analysis of Cytochrome P450 Monooxygenase Family from Artemisia

Artemisinin, a sesquiterpene lactone endoperoxide derived from Artemisia annua L, forms the basis of the most important medicines for treating malaria in use today. In the study, a total of 41 full genes coded cytochrome P450 monooxygenases were identified from NCBI. These genes were classified into 11 families in 3 gene clans according to sequence similarity. One of the first interesting features in sequence alignment was that the CYP82, CYP83 and CYP716 families specific in Arabidopsis genome were present in Artemisia, and the CYP92 specific in rice was also present in Artemisia. The physical and chemical properties and structure characteristics of the identified P450s were studied. The results showed their secondary structures were very similar and their senior structures mainly contained α-helix.

Purification and Spectral Characteristics of Cytochrome b-559 from Oxygen-evolving Photosystem Ⅱ Core Complexes of Spinach and Rice

Cytochrome b_559 in photosystem Ⅱ reaction center was purified from spinach ( Spinacia oleracea L.) and rice ( Oryza sativa L.) by a rapid and simple procedure. Their low temperature fluorescence emission and excitation spectra, ultraviolet fluorescence spectra and absolute absorption spectra were presented. The author's purification methods, which enhanced the yield of pure protein and shorted the time for isolation, have several advantages: 1. use of oxygen_evolving PSⅡ core complexes as the starting material in order to avoid disturbing from other cytochromes; 2. isocratic elution of cytochrome b_559 from a DEAE_Sephacel column for eliminating the impurity and yielding the protein in pure state; 3. a simple column procedure for removal of excess Triton X_100. Purified cytochromes b_559 from these species have similar optical spectra and mobility during gel electrophoresis under native conditions. From the results of novel electrophoresis (Tricine_SDS_PAGE), cytochrome b_559 from both spinach and rice reveal two polypeptide bands (apparent molecular weight 9 kD and 4 kD, respectively). By measuring of 77 K fluorescence spectra, it was shown that for the purified cytochrome b_559 there were two excitation peaks at 439 nm and 413 nm, and two emission peaks at 563 nm and 668 nm. This is the first indication that Cyt b_559 is able to emit fluorescence and also transfer excited electrons to chlorophyll. By the use of ultraviolet fluorescence spectra, it was demonstrated for the first time that the location of Trp residue could be in the hydrophobic transmembrane region of cytochrome b_559.