Association of tumor budding with clinicopathological features and prognostic value in stage III-IV colorectal cancer

BACKGROUND Tumor budding(TB)has emerged as a promising independent prognostic biomarker in colorectal cancer(CRC).The prognostic role of TB has been extensively studied and currently affects clinical decision making in patients with stage I and II CRC.However,existing prognostic studies on TB in stage III CRC have been confined to small retrospective cohort studies.Consequently,this study investigated the correlation among TB categories,clinicopathological features,and prognosis in stage III-IV CRC to further enhance the precision and individualization of treatment through refined prognostic risk stratification.AIM To analyze the relationship between TB categories and clinicopathological characteristics and assess their prognostic value in stage III-IV CRC to further refine the prognostic risk stratification of stage III-IV CRC.METHODS The clinical data of 547 CRC patients were collected for this retrospective study.Infiltration at the front edge of the tumor buds was counted according to the 2016 International Tumor Budding Consensus Conference guidelines.RESULTS Multivariate Cox proportional hazards regression analysis demonstrated that chemotherapy(P=0.004),clinical stage IV(P<0.001),≥4 regional lymph node metastases(P=0.004),left-sided colonic cancer(P=0.040),and Bd 2-3(P=0.002)were independent prognostic factors in patients with stage III-IV CRC.Moreover,the density of tumor infiltrating lymphocytes was higher in Bd 1 than in Bd 2-3,both in the tumor stroma and its invasive margin.CONCLUSION TB has an independent predictive prognostic value in patients with stage III-IV CRC.It is recommended to complete the TB report of stage III-IV CRC cases in the standardized pathological report to further refine risk stratification.

Mathematical Modeling of Cell Polarity Establishment of Budding Yeast

The budding yeast Saccharomyces cerevisiae is a powerful model system for studying the cell polarity establishment.The cell polarization process is regulated by signaling molecules,which are initially distributed in the cytoplasm and then recruited to a proper location on the cell membrane in response to spatial cues or spontaneously.Polarization of these signaling molecules involves complex regulation,so the mathematical models become a useful tool to investigate the mechanism behind the process.In this review,we discuss how mathematical modeling has shed light on different regulations in the cell polarization.We also propose future applications for the mathematical modeling of cell polarization and morphogenesis.

Summer Warming Limited Bud Output Drives a Decline in Daughter Shoot Biomass through Reduced Photosynthetis of Parent Shoots in Leymus chinensis Seedlings

Understanding how summer warming influences the parent and daughter shoot production in a perennial clonal grass is vital for comprehending the response of grassland productivity to global warming.Here,we conducted a simulated experiment using potted Leymus chinensis,to study the relationship between the photosynthetic activ-ity of parent shoots and the production of daughter shoots under a whole(90 days)summer warming scenario(+3°C).The results showed that the biomass of parents and buds decreased by 25.52%and 33.45%,respectively,under warming conditions.The reduction in parent shoot biomass due to warming directly resulted from decreased leaf area(18.03%),chlorophyll a(18.27%),chlorophyll b(29.21%)content,as well as a reduction in net photosynthetic rate(7.32%)and the maximum quantum efficiency of photosystem II(PSII)photochemistry(4.29%).The decline in daughter shoot biomass was linked to a decrease in daughter shoot number(33.33%)by warming.However,the number of belowground buds increased by 46.43%.The results indicated that long-term summer warming reduces biomass accumulation in parent shoot by increasing both limitation of stoma and non-stoma.Consequently,the parent shoot allocates relatively more biomass to the belowground organs to maintain the survival and growth of buds.Overall,buds,as a potential aboveground population,could remedy for the cur-rent loss of parent shoot density by increasing the number of future daughter shoots if summer warming subsides.

Peculiarity of transcriptional and H3K27me3 dynamics during peach bud dormancy

Bud dormancy facilitates the survival of meristems under harsh environmental conditions.To elucidate how molecular responses to chilling accumulation controlling dormancy in peach buds,chromatin immunoprecipitation sequencing to identify the H3K27me3 modifications and RNA sequencing of two peach cultivars with pronounced differences in chilling requirement were carried out,the results showed that genes associated with abscisic acid and gibberellic acid signal pathways play key roles in dormancy regulation.The results demonstrated that peach flower bud differentiation occurred continuously in both cultivars during chilling accumulation,which was correlated with the transcript abundance of key genes involved in phytohormone metabolism and flower bud development under adverse conditions.The more increased strength in high chillingrequirement cultivar along with the chilling accumulation at the genome-wide level.The function of the dormancy-associated MADS-box gene PpDAM6 was identified,which is involved in leaf bud break in peach and flower development in transgenic Nicotiana tabacum(NC89).In addition,PpDAM6 was positively regulated by PpCBF,and the genes of putative dormancy-related and associated with metabolic pathways were proposed.Taken together,these results constituted a theoretical basis for elucidating the regulation of peach bud dormancy transition.

Prognostic significance of tumor budding,desmoplastic reaction,and lymphocytic infiltration in patients with gastric adenocarcinoma

BACKGROUND Recent studies have shown that the tumor microenvironment significantly influences the behavior of solid tumors.In this context,Accumulated data suggests that pathological evaluation of tumor budding(TB),desmoplastic reaction(DR),and tumor-infiltrating lymphocytes(TILs)may be crucial in determining tumor behavior in the gastrointestinal tract.Regarding gastric adenocarcinoma(GAC),although some results suggest that TB and TILs may be effective in determining the course of the disease,the data do not agree.Moreover,very few studies have investigated the relationship between DR and survival.At present,the associations between tumor TB,DR and TILs in GAC patients have not been determined.AIM To establish the relationships between TB,DR,and TILs in patients with GAC and to assess their influence on prognosis.METHODS Our study group comprised 130 patients diagnosed with GAC.The definition of TB was established based on the International TB Consensus Conference.The DR was categorized into three groups according to the level of tumor stroma maturation.The assessment of TILs was conducted using a semiquantitative approach,employing a cutoff value of 5%.The statistical analysis of the whole group and 100 patients with an intestinal subtype of GAC was performed using SPSS version 27.RESULTS A significant correlation between peritumoral budding(PTB)and intratumoral budding(ITB)was noted(r=0.943).Tumors with high PTBs and ITBs had a greater incidence of immature DRs and low TILs(P<0.01).PTB and ITB were associated with histological subtype,lymph node metastasis(LNM),and stage(P<0.01).ITB,PTB,LNM,DR,and stage were significant risk factors associated with poor prognosis.The multivariate Cox regression analysis identified ITB,PTB,and LNM as independent prognostic variables(P<0.05).In intestinal-type adenocarcinomas,a positive correlation between PTB and ITB was noted(r=0.972).While univariate analysis revealed that LNM,stage,PTB,ITB,and DR were strong parameters for predicting survival(P<0.05),only PTB and ITB were found to be independent prognostic factors(P<0.001).CONCLUSION TB may be a potential prognostic marker in GAC.However,further studies are needed to delineate its role in pathology reporting protocols and the predictive effects of DR and TILs.

Artificial intelligence-based comprehensive analysis of immune-stemness-tumor budding profile to predict survival of patients with pancreatic adenocarcinoma

Objective:Pancreatic ductal adenocarcinoma(PDAC)is an aggressive malignancy.CD8^(+)T cells,cancer stem cells(CSCs),and tumor budding(TB)have been significantly correlated with the outcome of patients with PDAC,but the correlations have been independently reported.In addition,no integrated immune-CSC-TB profile for predicting survival in patients with PDAC has been established.Methods:Multiplexed immunofluorescence and artificial intelligence(AI)-based comprehensive analyses were used for quantification and spatial distribution analysis of CD8^(+)T cells,CD133^(+)CSCs,and TB.In vivo humanized patient-derived xenograft(PDX)models were established.Nomogram analysis,calibration curve,time-dependent receiver operating characteristic curve,and decision curve analyses were performed using R software.Results:The established‘anti-/pro-tumor’models showed that the CD8^(+)T cell/TB,CD8^(+)T cell/CD133^(+)CSC,TB-adjacent CD8^(+)T cell,and CD133^(+)CSC-adjacent CD8^(+)T cell indices were positively associated with survival of patients with PDAC.These findings were validated using PDX-transplanted humanized mouse models.An integrated nomogram-based immune-CSC-TB profile that included the CD8^(+)T cell/TB and CD8^(+)T cell/CD133^(+)CSC indices was established and shown to be superior to the tumor-nodemetastasis stage model in predicting survival of patients with PDAC.Conclusions:‘Anti-/pro-tumor’models and the spatial relationship among CD8^(+)T cells,CSCs,and TB within the tumor microenvironment were investigated.Novel strategies to predict the prognosis of patients with PDAC were established using AI-based comprehensive analysis and machine learning workflow.The nomogram-based immune-CSC-TB profile can provide accurate prognosis prediction for patients with PDAC.

Tumor budding as a potential prognostic marker in determining the behavior of primary liver cancers

Hepatocellular(HCC)and intrahepatic cholangiocarcinoma(ICC),the most common primary tumors of the liver,are among the most important causes of cancer deaths worldwide.Because patients with primary liver tumors are frequently diagnosed at an advanced stage and have high mortality,many efforts have been made to identify new markers to determine their behavior and treatment,similar to those in other solid organ tumors.Recently,morphological assessment of tumor budding(TB)has been revealed as a promising prognostic finding to predict tumor behavior and survival across several different tumor types.Currently,the TB score in colorectal cancer has been revealed as an important parameter in pathology report protocols to determine the course of the disease.Regarding the liver,despite enormous data showing that many mechanisms involved in TB are associated with tumor behavior in both HCC and ICC,studies focusing on the role of TB in predicting the behavior and prognosis of these tumors have started to be investigated very recently.The purpose of this review is to present data about TB in primary tumors of the liver,pointing out the potential role of this parameter in determining the course of the disease,and emphasize the need to increase the number of further studies focusing on the evaluation of this parameter with an overview of the mechanisms involved in TB.

Tumor budding in gastric cancer

The tumor,nodes,metastasis(TNM)staging system has long been the gold standard for the classification and prognosis of solid tumors.However,the TNM staging system is not without limitations.Prognostic heterogeneity exists within patients at the same stage.Therefore,the pursuit of other biomarkers with the potential to classify patients with cancer has never stopped.One of them,tumor budding(TB),has gained much success in colorectal cancer.In recent years,TB in gastric cancer has attracted much attention from researchers,beginning to reveal the molecular and biological aspects of this phenomenon in gastric cancer,and has emerged as a promising prognostic biomarker in gastric cancer,predicting disease progression and unfavorable survival.Therefore,it is time and essential to provide a holistic overview of TB in gastric cancer,which has not been achieved and is the aim of this review.

Brassinosteroid Biosynthetic Gene CmDWF4 Regulates Bud Outgrowth in Chrysanthemum morifolium

Brassinosteroids(BRs),a class of steroid phytohormones,play a critical role in plant growth and development.The DWF4 gene encodes a cytochrome P450 enzyme(CYP90B1),which is considered a rate-limiting enzyme in BR biosynthesis.Here,we identified a homologous gene of DWF4 in chrysanthemum,CmDWF4.This gene was predicted to encode 491 amino acid residues with a molecular weight of 56.2 kDa and an isoelectric point(pI)of 9.10.Overexpression of CmDWF4 in chrysanthemum was found to significantly increase growth rate,number,and length of lateral buds.Transcriptome analysis showed that multiple xyloglucan endotransglycosylase/hydrolase(XTH)family encoding genes associated with cell wall modification were up-regulated in CmDWF4-overexpressing lines.qRT-PCR assay confirmed the up-regulation of CmXTH6,CmXTH23,and CmXTH28 in CmDWF4-overexpression line.Overall,this work establishes a mechanism by which BR biosynthetic gene CmDWF4 promotes lateral bud outgrowth in chrysanthemum,possibly through regulating cell elongation and expansion.

Research Progress of Flower Bud Differentiation of Apple

Flowering is a prerequisite for apple fruiting,and apple flower buds are mixed buds,that is,the vegetative organs and flower structure exist in the same terminal bud simultaneously,which are formed in the year before flowering and fruiting,mainly including spur terminal buds and axillary buds.The infrequent formation of flower buds during its growth and biennial bearing are closely related to flower bud differentiation.Therefore,this paper reviews the research progress of flower bud differentiation of apple from the morphological differentiation,plant hormones and flowering-related genes,in order to provide a theoretical reference for efficient cultivation and stable yield of apple.

Effect of Shoot Control on Flower Bud Differentiation,Flowering,and Fruit Setting in Zanthoxylum armatum DC.

In this study,newly sprouted shoots of Zanthoxylum armatum(Z.armatum),which were collected after the harvesting period,were used as the primary experimental specimens.A randomized block design and paraffin sectioning method were used to investigate the flower bud differentiation process and the quantity and vitality of buds.Furthermore,the study examined the response of flowering and fruiting to cultivation methods for shoot growth,including layering and plant growth regulator application.The results showed that(a)layering and application of plant growth regulators for Z.armatum accelerated the process of flower bud differentiation by approximately 20 days compared to the control group.Additionally,both shoot control methods generated more and larger bud primordia and perianth primordia during the same differentiation phase.(b)The application of plant growth regulators resulted in well-developed buds,exhibiting higher levels of flower bud differentiation than the layering method.The quality of flower bud formation for both shoot control methods was superior to that of the control group.(c)The flowering phenological period was relatively consistent between the two cultivation methods,but the fruit maturity phase for shoot-controlled trees occurred 20 days earlier than the control group.(d)Both layering and the application of plant growth regulators significantly decreased the rates of unfertilized flower shedding and fruit shedding.However,no significant difference was noted in fruit setting per inflorescence and per flower between the two methods and the control.The effect of altitude for both methods on the fruit setting was not significant.Under both shoot control methods,the Z.armatum exhibited earlier morphological differentiation of flower buds,faster differentiation process,improved flower bud quality,and significantly decreased rates of flower and fruit shedding.Thus,these cultivation methods demonstrated the potential to promote flowering,improve fruit setting,and reduce fruit shedding in Z.armatum.

METTL3修饰的RNASEH1-AS1通过BUD13/ANXA2/Wnt/β-catenin轴调控结直肠癌SW480细胞的恶性生物学行为

目的:探究甲基转移酶样蛋白3(METTL3)修饰的RNASEH1-AS1通过BUD13/膜联蛋白A2/Wnt/β-连环蛋白(BUD13/ANXA2/Wnt/β-catenin)轴调控结直肠癌细胞SW480恶性生物学行为的分子机制。方法:选取2022年6月至2022年11月间在复旦大学附属中山医院厦门医院手术治疗的24例CRC患者,收集患者的CRC组织和对应的癌旁组织,用qPCR法检测其中METTL3、RNASEH1-AS1、BUD13、ANXA2、β-catenin、GSK-3β mRNA的表达,用Pearson法分析CRC组织中RNASEH1-AS1表达分别与METTL3和BUD13表达的相关性。常规培养结直肠癌细胞SW480,分为sh-NC组、sh-RNASEH1-AS1组、NC组、sh-METTL组、si-NC组、si-BUD13组、sh-RNASEH1-AS1+pc-NC组、sh-RNASEH1-AS1+pc-ANXA2组、sh-METTL+pc-NC组、sh-METTL+pc-ASEH1-AS1组,用Lipofectamine?2000转染试剂将sh-NC、sh-RNASEH1-AS1、sh-NC、sh-METTL、si-NC、si-BUD13、sh-RNASEH1-AS1+pc-NC、sh-RNASEH1-AS1+pc-ANXA2、sh-METTL+pc-NC、sh-METTL+pc-ASEH1-AS1分别转染SW480细胞,用qPCR法检测后SW480细胞中METTL3、RNASEH1-AS1、BUD13、ANXA2的表达,细胞克隆形成实验检测转染后各组SW480细胞的增殖能力,FCM术检测转染后各组SW480细胞的凋亡情况,细胞划痕实验检测转染后各组SW480细胞的迁移能力,WB法检测转染后各组SW480细胞中ANXA2、β-catenin、p-β-catenin、GSK-3β、p-GSK-3β、c-Myc、cyclinD1蛋白表达,RNA免疫沉淀(RIP)法检测RNASEH1-AS1与BUD1、BUD1与ANXA2的靶向关系。结果:数据库CRC数据分析和中国人CRC组织和癌旁组织的qPCR法检测结果均显示,与癌旁组织相比CRC组织中METTL3、RNASEH1-AS1、BUD13、ANXA2、β-catenin、GSK-3β均呈明显高表达(均P<0.01),且RNASEH1-AS1表达与METTL3(r=0.698,P<0.01)、BUD13(r=0.784,P<0.01)的表达呈正相关。在结直肠癌各细胞中METTL3、RNASEH1-AS1、BUD13、ANXA2 mRNA均呈高表达(均P<0.05);敲减RNASEH1-AS1或METTL3后SW480细胞中RNASEH1-AS1、BUD13、ANXA2表达显著降低(均P<0.05),而过表达RNASEH1-AS1后上述分子表达明显上调(均P<0.05);敲减RNASEH1-AS1或METTL3可抑制SW480的增殖、迁移和p-β-catenin、p-GSK-3β、c-Myc、cyclinD1蛋白的表达,促进其凋亡(均P<0.05),而过表达RNASEH1-AS1则可促进SW480增殖、迁移和p-β-catenin、p-GSK-3β、c-Myc、cyclinD1蛋白的表达和抑制其凋亡(均P<0.05);RNASEH1-AS1通过招募BUD13靶向促进ANXA2的表达(均P<0.05);过表达ANXA2可部分逆转敲减RNASEH1-AS1对SW480细胞的影响(均P<0.05)。结论:METTL3修饰的RNASEH1-AS1通过BUD13/ANXA2/Wnt/β-catenin轴调控SW480细胞的恶性生物学行为。

分体刀具式名优茶采摘末端执行器设计与试验优化

针对名优茶机械化采摘过程中侧芽无法采摘的问题,根据顶芽、侧芽及茶梗的相关参数并结合茶园环境设计了一种末端执行器,利用分体式刀具的刀齿弯曲变形适应茶梗的干扰从而采摘侧芽。通过有限元仿真刀具切割侧芽得到采摘成功率的影响因素为刀齿宽度、刀齿长度及刀具厚度;采用三因素三水平的中心组合设计与响应面分析法研究各因素对采摘成功率的交互影响;以采摘成功率为响应值建立二次回归模型,确定各因素对采摘成功率的影响显著性主次排序为:刀齿长度、刀齿宽度、刀具厚度。以采摘成功率为目标对各试验因素进行优化,得到优化后的刀齿宽度、刀具厚度、刀齿长度分别为2.6、0.9、20.0 mm。采用优化后的参数进行茶园采摘试验,结果表明,末端执行器能够有效完成茶叶采摘工作,顶芽、侧芽采摘成功率分别为93%、63%,试验值与预测值的相对误差小于5%,优化模型结果可靠。

甘蔗健康种苗双芽段槽带式种植机排种性能优化研究

甘蔗健康种苗种植技术是提高单产水平和品质、降低生产成本的有效措施之一,而目前国内甘蔗种植装备不成熟,直接限制了这一技术的推广和应用。为此,以有序排列的甘蔗健康种苗双芽段蔗种为研究对象,对团队研发的2CZD-2A型半自动双芽甘蔗种植机排种性能进行优化,设计了高频电磁振动自动喂入器与仿形排种同步驱动器。利用Solid Edge ST5三维软件建模进行仿真分析,建立试验台进行多因素正交组合试验,采集数据并利用SPSS进行处理建立回归方程,运用Design Expert绘制响应曲面,分析因素之间交互作用,利用MatLab进行参数优化,最终进行田间试验验证。研究结果表明:同步驱动机构增加了排种均匀度,当带轮转速为10r/s、振动幅度为18.5mm、行进速度为0.65m/s时,排种均匀度达到94.18%,与优化结果偏差小于5%,满足设计要求;高频振动与动力源振动无干涉,验证了振动器梳理方案的可行性,可为全自动种植机的研发提供参考。

软枣猕猴桃“奇异莓6号”无芽茎段离体再生技术研究

取无芽茎段为外植体进行离体培养,具有成本低、取材方便、材料充足等优点。为克服软枣猕猴桃无芽茎段诱导再生率低的问题,以“奇异莓6号”软枣猕猴桃无菌苗无芽茎段为外植体,探究了不同植物生长调节剂、光照强度、温度、苗龄对不定芽诱导的影响,以及不同浓度IBA对生根的影响。结果表明,最佳外植体为苗龄30 d的无芽茎段,在光照12 h/d、光照强度50 lx、20℃下不定芽诱导的最适培养基为MS+2 mg/L ZT,不定芽以间接途径发生,培养40 d无芽茎段两端开始形成淡绿色愈伤组织,培养45 d愈伤组织表面出现红色小点,开始形成不定芽,培养55 d愈伤组织诱导率、愈伤组织分化率及不定芽数均到最大,分别为100%、100%及18.87个/块。待苗长至3 cm左右时转到MS+0.4 mg/L IBA中进行生根培养,培养30 d生根率可达100%,平均根数为8.53条/株,根长1.68 cm,根粗0.14 cm。

基于顶芽智能识别的棉花化学打顶系统研究

设计了基于顶芽智能识别的棉花化学打顶系统,为实现精准作业,合理高效使用棉花化学打顶药剂,以减少因化学打顶剂的过度使用造成的环境污染。该系统主要由棉花顶芽识别系统、控制系统和喷施系统组成。采用YOLO v5s算法构建棉花顶芽识别模型。控制系统采用STM32F407单片机,负责接收识别系统的信号,并对各个棉花打顶剂管道进行控制。同时,显示界面能够实时显示机具行驶速度、药液流量、打顶剂液位等参数。试验结果表明,在田间全天光照试验中,上午和下午时间段识别效果最优;在速度0.4 m/s下,平均识别率约为94%;信号发送区间为100 mm时,成功向下位机发送信号的成功率达到92%;田间对靶喷施试验表明,有效喷施率为94%,满足作业要求。

天红2号苹果花芽分化期枝条和叶片碳水化合物含量和C/N变化

以天红2号苹果为试材,研究不同砧木短枝和中枝在花芽分化期间叶片和枝条中碳水化合物含量和C/N变化情况。结果表明,稳产期天红2号苹果成花率不受砧木影响。整个花芽分化期,无论嫁接在SH40中间砧还是八棱海棠乔砧上,在同一枝类中,天红2号苹果叶片可溶性糖、蔗糖、果糖和氮含量高于枝条,淀粉含量和C/N低于枝条。嫁接在SH40中间砧上的天红2号苹果成花率高的短枝叶片淀粉和果糖含量低于成花率低的中枝叶片,可溶性糖、蔗糖含量和C/N于花芽分化初期至花瓣原基分化期高于中枝叶片,短枝枝条可溶性糖、果糖含量和C/N低于中枝枝条,短枝枝条淀粉含量于花瓣原基分化期前高于中枝枝条;嫁接在八棱海棠乔砧上的天红2号苹果成花率高的短枝叶片可溶性糖、淀粉、果糖含量和C/N低于成花率低的中枝叶片,短枝枝条可溶性糖、果糖含量和C/N低于中枝枝条,短枝枝条淀粉含量于转化期低于中枝枝条。说明碳水化合物含量和C/N的高低对苹果成花不起决定性作用。在整个花芽分化期,叶片中可溶性糖含量呈上升趋势,枝条中淀粉含量和C/N呈波动性上升趋势,说明天红2号苹果花芽形态分化需要碳水化合物和C/N的积累。

一种优化的桑树花芽石蜡切片制作方法

针对常规石蜡切片方法无法获得完整桑树花芽切片的问题,以“无籽大十”品种桑树花芽为供试材料,在常规石蜡切片技术基础上,对石蜡切片样品制作过程中固定、软化、脱水、透明及染色等环节进行了优化。结果表明,使用15%氢氟酸软化后,采用优化后的系列脱水、透明等步骤进行制片,可以使切片连续性、完整性得到明显提高。通过切片显微观察,可见细胞轮廓明显、裂痕较少、结构较完整,染色较清晰,并且对发育后期的花芽效果更为明显。优化后的制样流程解决了常规制片出现浸蜡不彻底、组织变脆、蜡带不连续、内部结构不完整等一系列问题。该研究可以从解剖学上为桑树花芽发育形态和花芽分化机制研究提供技术参考。

广东番茄巨芽病植原体的分子鉴定

2022年,对在广东省湛江市廉江市田间发现的疑似番茄巨芽病病株,利用分子生物学方法对其相关植原体进行了鉴定。以番茄病株叶片总DNA为模板,利用植原体16S rRNA基因通用引物R16mF2/R16mR1进行PCR扩增,获得了广东番茄巨芽病植原体(TBB-GD-2022)16S rRNA基因片段(1 430 bp, GenBank登录号为ON102780)。16S rRNA基因序列相似性分析显示,TBB-GD-2022与16SrⅡ组植原体菌株的相似性较高,为96.82%~100%,其中与隶属于16SrⅡ-V亚组的6个植原体株系相似性为100%。系统进化分析显示,TBB-GD-2022与16SrⅡ组各植原体株系聚类在一个大分支,并与16SrⅡ-V亚组成员聚类在一个小分支,亲缘关系较近。16S rRNA基因相似系数分析表明,TBB-GD-2022与16SrⅡ-V亚组的参照株系‘Praxelis clematidea’ phyllody phytoplasma (GenBank登录号:KY568717)的相似系数为1.00。上述研究结果表明,广东番茄巨芽病植原体隶属16SrⅡ-V亚组成员。本文首次报道在广东发现番茄巨芽病,通过其16S rRNA序列分析进一步确定了其相关植原体的分类地位,为该病害的防控提供了科学依据。

短期超低氧处理抑制花生芽常温物流褐变作用的研究

探究不同超低氧处理时间对常温物流中花生芽褐变的抑制效果及作用机制,为实际物流包装应用提供理论依据。采用包装袋中充100%N2方式实现超低氧处理,然后分别在超低氧4、8、12 h后将包装袋打微孔,实现自发式气调,以不充氮直接微孔组为对照,于23℃下贮藏并测定相关指标。结果表明,直接微孔组因包装内含氧量相对较高对抑制常温下花生芽采后褐变无法起到积极作用。超低氧12 h微孔组由于在超低氧环境中处理时间过长,会引发无氧呼吸,从而产生过量的乙醇、乙醛对细胞造成毒害作用,导致花生芽生理代谢紊乱。而超低氧4、8 h微孔组均能形成花生芽适应的自发气调环境,有效降低呼吸强度,通过提高与活性氧代谢有关的超氧化物歧化酶、过氧化氢酶、过氧化物酶的活性,增强自由基清除能力,抑制超氧阴离子的积累,减弱了膜脂过氧化,其相对电导率和丙二醛含量的上升得到抑制,细胞膜的完整性得以更好地保护;同时超低氧4、8 h还抑制了多酚氧化酶活性的上升,保持花生芽良好的色泽,进而延缓花生芽的褐变;其中超低氧8 h处理的效果最佳。