• 【微卫星标记显示,富士山主要演替性火山沙漠中嗜水球藻种群的遗传结构。】 复制标题 收藏 收藏
    DOI:10.1111/j.1469-8137.2004.01221.x 复制DOI
    作者列表:Wu B,Nara K,Hogetsu T
    BACKGROUND & AIMS: :Polymorphic simple sequence repeat (SSR) markers were used to investigate the genetic structure in a Cenococcum geophilum population associated with Salix reinii in an early successional volcanic desert at Gotenba, on the south-eastern slope of Mount Fuji in Japan, and in three other populations associated with the same host at more developed sites on the mountain, one at Fujinomiya and two at Subashiri. The genotype richness of C. geophilum tended to be higher in more developed vegetation patches as well as in more developed sites, suggesting that genotype richness increased with advanced succession because new genotypes might have been introduced into these sites over time. High genotypic similarity was observed between the Gotenba and Fujinomiya populations but not between the Gotenba and Subashiri populations, suggesting that C. geophilum genotypes in Gotenba were introduced from the direction of Fujinomiya. Genotypes in the Gotenba population were clearly distinguishable into two groups. The absence of any intermediate genotype suggests the absence of frequent recombination in this C. geophilum population associated with early successional vegetation.
    背景与目标: :多态性简单序列重复(SSR)标记用于研究御殿场,日本富士山东南坡以及其他三个地方的早期演替火山沙漠中与柳柳相关的土生白尾藻种群的遗传结构。与同一个寄主相关的种群位于山上较发达的地点,其中一个位于富士宫,两个位于Subashiri。在更发达的植被斑块和更发达的地点,地衣梭菌的基因型丰富度往往更高,这表明基因型丰富度随着高级演替的增加而增加,因为随着时间的流逝,新的基因型可能已被引入这些地点。在御殿场和富士宫族之间观察到高的基因型相似性,但御殿场和Subashiri种群之间没有观察到相似性,这表明御殿场的嗜地衣芽孢杆菌基因型是从富士宫方向引入的。 Gotenba人群中的基因型明显可分为两组。缺少任何中间基因型表明与早期演替植被相关的这种嗜地衣梭菌种群中没有频繁的重组。
  • 【干旱和空气变暖会影响与栎,栎和白藜相关联的嗜碱炭黑球菌的丰度和外酶谱。】 复制标题 收藏 收藏
    DOI:10.1111/j.1438-8677.2012.00614.x 复制DOI
    作者列表:Herzog C,Peter M,Pritsch K,Günthardt-Goerg MS,Egli S
    BACKGROUND & AIMS: :The present study aimed to elucidate the influence of drought and elevated temperature on relative abundance and functioning of the ectomycorrhizal fungus Cenococcum geophilum on three oak species differing in adaptation to a warm and dry climate. The experiment QUERCO comprised three Quercus species (Q. robur, Q. petraea, Q. pubescens) grown for 3 years under four treatments: elevated air temperature, drought, a combination of the two, and control. Fine root samples were analysed for relative abundance and potential extracellular enzyme activities of ectomycorrhizae of C. geophilum, a fungal species known to be drought resistant. The relative abundance of C. geophilum on the roots of the oak species was significantly increased by temperature, decreased by drought, but unchanged in the combined treatment compared to the control. Although the extent of treatment effects differed among oak species, no significant influence of tree species on relative abundance of C. geophilum was detected. Exoenzyme activities of C. geophilum on Q. robur and Q. petraea (but not Q. pubescens) significantly increased in the combined treatment, but for all oak species were reduced under drought and air warming alone compared to the control. There was a significant negative correlation between abundance of C. geophilum and its leucine aminopeptidase activity. As this enzyme is not frequent among ectomycorrhizal fungi, this emphasises the functional importance of C. geophilum in the ectomycorrhizal community. Our results indicate that increased temperature and drought will influence the relative abundance and enzyme activity of C. geophilum. However, both the Quercus species and C. geophilum tolerated warming and strong drought.
    背景与目标: :本研究旨在阐明干旱和高温对三种不同适应温暖干燥气候的橡树外生菌根真菌Cenococcum geophilum相对丰度和功能的影响。实验QUERCO包括3种在3年中生长的栎类(Q.robur,Q.petraea,Q.pubescens):升高的温度,干旱,二者的结合和控制。分析了细根样品的地衣芽孢杆菌(C.geophilum)的外生菌根的相对丰度和潜在的胞外酶活性,这是一种已知具有抗旱性的真菌。橡木树根上的地衣梭菌的相对丰度随着温度的升高而显着增加,由于干旱而降低,但与对照相比,联合处理中的相对丰度没有变化。尽管橡木树种的处理效果程度不同,但未检测到树木种对C.geophilum相对丰度的显着影响。与对照相比,组合处理中地衣梭菌对罗布氏菌和白屈菜的外酶活性显着增加,但对所有橡树种而言,仅在干旱和空气加热下,其外酶活性显着降低。嗜碱梭菌的丰度与其亮氨酸氨肽酶活性之间存在显着的负相关性。由于这种酶在外生菌根真菌中不常见,因此强调了C.geophilum在外生菌根群落中的功能重要性。我们的结果表明,温度升高和干旱会影响地衣梭菌的相对丰度和酶活性。但是,栎属物种和C.geophilum都可以忍受变暖和强烈干旱。
  • 【土生芽孢菌子囊菌的分泌组分析。】 复制标题 收藏 收藏
    DOI:10.3389/fmicb.2018.00141 复制DOI
    作者列表:de Freitas Pereira M,Veneault-Fourrey C,Vion P,Guinet F,Morin E,Barry KW,Lipzen A,Singan V,Pfister S,Na H,Kennedy M,Egli S,Grigoriev I,Martin F,Kohler A,Peter M
    BACKGROUND & AIMS: :Introduction Guidelines have been recommending the use of arteriovenous fistula among the hemodialysis population, but no clear conclusion has emerged with regard to the adequate access type in octogenarians. In this paper, the outcomes of arteriovenous fistula in octogenarian cohort were presented for death-censored cumulative patency rate, complications, and patients' survival rate. Methods A retrospective review of 88 consecutive arteriovenous fistula interventions in 70 octogenarian patients were performed at one referral institution between January 2010 and June 2014. The patients' records were analyzed and postoperative complications were documented. Death-censored cumulative arteriovenous fistula patency rates were calculated, and Kaplan-Meier method was used to analyze patient survival for 24 months. FINDINGS:Eighty-eight arteriovenous fistula constructions and six salvage procedures were performed in 70 octogenarians. Fifty-four (61.3%) forearm and 34 (38.7%) upper arm fistulas were created. All types of fistulas had 6-, 12-, 18-, and 24-month death-censored cumulative patency rates of 63.6%, 58.3%, 48.8%, and 41.4%, respectively. The primary failure rate was 40.9%. A total of 15 complications were documented as edema, hematoma/bleeding, infection, distal ischemia, and venous aneurysm, all of which had been treated. Patient survival rates for 12 and 24 months were 68.5% and 58.5%, respectively. DISCUSSION AND CONCLUSION:This analysis regarding arteriovenous fistula in octogenarian end-stage renal disease patients figured out equal death-censored cumulative patency compared to nonelderly, and two-year survival rate was acceptable. This study strengthens the argument that arteriovenous fistula should be the best proper choice in selected octogenarians; older age only should not be considered as an absolute contraindication for arteriovenous fistula creation in octogenarians; and patient-based approach should be applied.
    背景与目标: :指南已经建议在血液透析人群中使用动静脉瘘,但是对于八岁以上人群的适当进入方式尚无明确的结论。在本文中,针对死于死亡的累积通畅率,并发症和患者的存活率,提出了八十岁队列中动静脉瘘的结局。方法回顾性分析2010年1月至2014年6月在一家转诊机构对70例八岁以上患者进行的88例动静脉瘘的连续干预措施。分析了患者的病历并记录了术后并发症。计算死亡检查的累积动静脉瘘通畅率,并使用Kaplan-Meier方法分析患者24个月的存活率。
    研究结果:在70名高龄者中进行了88例动静脉瘘的构造和6例挽救程序。创造了五十四(61.3%)个前臂和34个(38.7%)的上臂瘘管。所有类型的瘘管的6个月,12个月,18个月和24个月死亡检查的累积通畅率分别为63.6%,58.3%,48.8%和41.4%。主要失败率为40.9%。总共记录了15种并发症,如水肿,血肿/出血,感染,远端缺血和静脉动脉瘤,所有这些均已得到治疗。 12和24个月的患者生存率分别为68.5%和58.5%。
    讨论与结论:这项关于八十岁末期肾脏疾病患者动静脉瘘的分析表明,与非老年人相比,死亡检查的累积通畅性相等,两年生存率是可以接受的。这项研究加强说法,动静脉瘘应在选定八旬老人中寻找最佳的选择;仅年龄较大的人不应被视为八岁老人动静脉瘘形成的绝对禁忌症;并且应采用基于患者的方法。
  • 【接种Pisolithus tinctorius和Cenococcum geophilum对铜污染土壤中的松树的影响可增强植物修复作用。】 复制标题 收藏 收藏
    DOI:10.1080/15226514.2016.1244155 复制DOI
    作者列表:Wen Z,Shi L,Tang Y,Shen Z,Xia Y,Chen Y
    BACKGROUND & AIMS: :Status epilepticus (SE) is a severe neurological condition with significant morbidity and mortality. A reliable tool for prognosis is needed to take decision regarding treatment strategies. We compared 2 available prognostic scores of outcome: the Status Epilepticus Severity Score (STESS) and the Epidemiology-based Mortality score in SE (EMSE). We included 46 patients with SE evaluated out the last 5years in our hospital. We excluded patients with postanoxic encephalopathy or incomplete data. Among the 46 patients with SE, in-hospital mortality was 28%. The receiver operating characteristic (ROC) curve for predicting of death by STESS had an area under the curve (AUC) of 0.80 with cutoff point ≥4. The best EMSE variable combination to predict mortality was EMSE-AEL using an optimized cutoff point of 34 (age/etiology/loss of consciousness) with an area under the ROC of 0.79. The STESS and EMSE would be useful tools to predict in-hospital mortality in SE.
    背景与目标: :癫痫持续状态(SE)是一种严重的神经系统疾病,发病率和死亡率均很高。需要可靠的预后工具来做出有关治疗策略的决策。我们比较了2种可用的预后结果评分:癫痫持续程度评分(STESS)和基于流行病学的SE死亡率评分(EMSE)。我们纳入了过去5年在我们医院评估过的46例SE患者。我们排除了缺氧性脑病或数据不完整的患者。在46例SE患者中,院内死亡率为28%。用于通过STESS预测死亡的接收器工作特性(ROC)曲线在曲线下(AUC)的面积为0.80,且截止点≥4。预测死亡率的最佳EMSE变量组合是EMSE-AEL,其最佳截断点为34(年龄/病因/意识丧失),ROC下面积为0.79。 STESS和EMSE将是预测SE住院死亡率的有用工具。
  • 【重新审视拉丁美洲的Cenococcum geophilum sensu lato的系统发育多样性和隐性物种。】 复制标题 收藏 收藏
    DOI:10.1007/s00572-016-0690-7 复制DOI
    作者列表:Obase K,Douhan GW,Matsuda Y,Smith ME
    BACKGROUND & AIMS: :Pseudoalteromonas is a genus of Gram-negative and is ubiquitously distributed in the ocean. Many Pseudoalteromonas species are capable of producing pigments, which can serve as an alternative source to replace synthetic pigments used in the food industry. Prodigiosins belong to a family of secondary metabolite characterized by a common pyrrolyl pyrromethane skeleton, and have been successfully applied to yogurt, milk and carbonated drinks as substitutes for synthetic additives. The strain Pseudoalteromonas rubra SCSIO 6842 can produce cycloprodigiosin and harbors a conjugative plasmid. Here we report the complete genome of P. rubra SCSIO 6842 for a better understanding of the molecular basis of cycloprodigiosin production and regulation.
    背景与目标: :Pseudoalteromonas是革兰氏阴性菌,在海洋中无处不在。许多假单胞菌属物种能够生产色素,可以用作替代食品工业中使用的合成色素的来源。 Prodigiosins属于次级代谢产物家族,其特征是具有常见的吡咯基吡咯甲烷骨架,并且已成功应用于酸奶,牛奶和碳酸饮料中,以替代合成添加剂。麻风假单胞菌SCSIO 6842菌株可产生环prodigiosin,并带有结合质粒。在这里,我们报告了P​​. rubra SCSIO 6842的完整基因组,以更好地了解环己酮的生产和调控的分子基础。
  • 【Cenococcum geophilum Fr.的综合蛋白质组分析。作为发现与干旱有关的蛋白质的工具。】 复制标题 收藏 收藏
    DOI:10.1016/j.jprot.2012.04.039 复制DOI
    作者列表:Kerner R,Delgado-Eckert E,Del Castillo E,Müller-Starck G,Peter M,Kuster B,Tisserant E,Pritsch K
    BACKGROUND & AIMS: :Cenococcum geophilum is a widely distributed ectomycorrhizal fungus potentially playing a significant role in resistance and resilience mechanisms of its tree hosts exposed to drought stress. In this study, we performed a large scale protein analysis in pure cultures of C. geophilum in order to gain first global insights into the proteome assembly of this fungus. Using 1-D gel electrophoresis coupled with ESI-MS/MS, we indentified 638 unique proteins. Most of these proteins were related to the metabolic and cellular processes, and the transport machinery of cells. In a second step, we examined the influence of water deprivation on the proteome of C. geophilum pure cultures at three time points of gradually imposed drought. The results indicated that 12 proteins were differentially abundant in mycelia subjected to drought compared to controls. The induced responses in C. geophilum point towards regulation of osmotic stress, maintainance of cell integrity, and counteracting increased levels of reactive oxygen species formed during water deprivation.
    背景与目标: :Cenococcum geophilum是一种广泛分布的外生菌根真菌,可能在暴露于干旱胁迫的树木宿主的抗性和复原力机制中发挥重要作用。在这项研究中,我们在纯净的嗜水梭状芽孢杆菌培养物中进行了大规模蛋白质分析,以初步了解这种真菌的蛋白质组学。使用一维凝胶电泳结合ESI-MS / MS,我们鉴定出638个独特的蛋白质。这些蛋白质大多数与代谢和细胞过程以及细胞的运输机制有关。在第二步中,我们研究了在逐渐施加干旱的三个时间点,缺水对C. geophilum纯培养物蛋白质组的影响。结果表明,与对照相比,干旱的菌丝体中12种蛋白质差异丰富。嗜水梭状芽胞杆菌的诱导反应指向调节渗透胁迫,维持细胞完整性和抵消在缺水期间形成的活性氧种类的增加水平。
  • 【蛇纹土中嗜水球藻分离株对镍的适应性耐受性证据。】 复制标题 收藏 收藏
    DOI:10.1007/s00572-008-0211-4 复制DOI
    作者列表:Gonçalves SC,Martins-Loução MA,Freitas H
    BACKGROUND & AIMS:
    背景与目标:
  • 【与推断嗜水球藻物种复合体内的种群结构有关的重大多样性和潜在问题。】 复制标题 收藏 收藏
    DOI:10.3852/mycologia.99.6.812 复制DOI
    作者列表:Douhan GW,Huryn KL,Douhan LI
    BACKGROUND & AIMS: :Cenococcum geophilum is perhaps the most widely distributed and most recognized ectomycorrhizal fungus with a host range of more than 200 tree species from 40 genera of both angiosperms and gymnosperms. We conducted a phylogenetic analysis on a large collection of isolates (n=74) from North America and Europe based on glyceraldehyde 3-phosphate dehydrogenase (gpd). A subset of isolates (n=22) also was analyzed with the more conservative LSU-rDNA locus. Significant nucleotide diversity was detected (approximately 20%) in the gpd region and the LSU-rDNA analysis supported that the C. geophilum isolates studied were monophyletic but distinct from two isolates, Am5-1 and N2-10, which previously were used in population genetic studies of this species. These results suggest that Am5-1 and N2-10 are likely two undescribed species or even genera. Our results suggest that C. geophilum sensu lato is a species complex and support previous molecular, physiological and morphological studies that have shown significant diversity in C. geophilum. This study also revealed that caution is advised when conducting population genetic studies in C. geophilum due to the possibility of pooling unrelated isolates. This potential problem also has implications for other fungal taxa because cryptic species routinely have been found in recent years based on molecular data.
    背景与目标: :Cenococcum geophilum可能是分布最广,最广为人知的外生菌根真菌,其寄主范围来自40属被子植物和裸子植物的200多种树种。我们基于3-磷酸甘油醛脱氢酶(gpd)对北美和欧洲的大量分离株(n = 74)进行了系统发育分析。还使用更保守的LSU-rDNA基因座分析了分离株的一个子集(n = 22)。在gpd区检测到显着的核苷酸多样性(约20%),LSU-rDNA分析支持所研究的嗜地衣芽孢杆菌分离株是单系分离的,但不同于以前在人群中使用的两个分离株Am5-1和N2-10。该物种的遗传研究。这些结果表明,Am5-1和N2-10可能是两个未描述的物种,甚至属。我们的结果表明,C。geophilum sensu lato是一个物种复合体,支持以前的分子,生理和形态学研究,这些研究显示Geophilum的显着多样性。这项研究还表明,由于可能合并无关的分离株,因此在进行嗜地梭状芽胞杆菌的种群遗传研究时,建议谨慎行事。这个潜在的问题也对其他真菌类群有影响,因为近年来基于分子数据通常发现了隐性物种。
  • 【铁铁蛋白-嗜水球藻的外生菌根铁载体。】 复制标题 收藏 收藏
    DOI:10.1023/a:1013188823076 复制DOI
    作者列表:Haselwandter K,Winkelmann G
    BACKGROUND & AIMS: :The ectomycorrhizal fungus Cenococcum geophilum was grown in low-iron medium and the excreted siderophores were extracted, purified and analyzed by HPLC. The principal hydroxamate siderophore produced, was identified as ferricrocin as confirmed by analytical HPLC, FAB-mass spectrometry and 1H- and 13C-NMR spectra. Although the occurrence of ferricrocin has been shown earlier to occur in the ericoid mycorrhizal fungi, this is the first report of ferricrocin in a true ectomycorrhizal fungus which is taxonomically related to the ascomycetes.
    背景与目标: :外生菌根真菌Cenococcum geophilum在低铁培养基中生长,提取的铁载体被提取,纯化并通过HPLC分析。产生的主要异羟肟酸酯铁载体经分析HPLC,FAB质谱,1H和13C-NMR光谱确认为铁三茂铁。尽管铁蛋白的发生早已显示在类固醇菌根真菌中,但这是铁锈菌在真正的外生菌根真菌中的第一个报道,该真菌在分类学上与子囊菌有关。
  • 【葡萄牙蛇纹石土壤中的Cenococcum geophilum分离物中对Ni的遗传多样性和体外体外响应差异。】 复制标题 收藏 收藏
    DOI:10.1007/s00572-007-0145-2 复制DOI
    作者列表:Gonçalves SC,Portugal A,Gonçalves MT,Vieira R,Martins-Loução MA,Freitas H
    BACKGROUND & AIMS: :Amplified fragment length polymorphism (AFLP) analysis was used to investigate the genetic diversity in isolates of the ectomycorrhizal fungus Cenococcum geophilum from serpentine and non-serpentine soils in Portugal. A high degree of genetic diversity was found among C. geophilum isolates; AFLP fingerprints showed that all the isolates were genetically distinct. We also assessed the in vitro Ni sensitivity in three serpentine isolates and one non-serpentine isolate. Only the non-serpentine isolate was significantly affected by the addition of Ni to the growth medium. At 30 microg g(-1) Ni, radial growth rate and biomass accumulation decreased to 73.3 and 71.6% of control, respectively, a highly significant inhibitory effect. Nickel at this concentration had no significant inhibitory effect on serpentine isolates, and so the fitness of serpentine isolates, as evaluated by radial growth rate and biomass yield, is likely unaffected by Ni in the field. In all isolates, the Ni concentration in the mycelia increased with increasing Ni concentration in the growth medium, but two profiles of Ni accumulation were identified. One serpentine isolate showed a linear trend of Ni accumulation. At the highest Ni exposure, the concentration of Ni in the mycelium of this isolate was in the hyperaccumulation range for Ni as defined for higher plants. In the remaining isolates, Ni accumulation was less pronounced and seems to approach a plateau at 30 microg g(-1) Ni. Because two profiles of Ni accumulation emerged among our Ni-insensitive serpentine isolates, this result suggests that different Ni detoxification pathways may be operating. The non-serpentine isolate whose growth was significantly affected by Ni was separated from the other isolates in the genetic analysis, suggesting a genetic basis for the Ni-sensitivity trait. This hypothesis is further supported by the fact that all isolates were maintained on medium without added Ni to avoid carry-over effects. However, because AFLP analysis failed to distinguish between serpentine and non-serpentine isolates, we cannot conclude that Ni insensitivity among our serpentine isolates is due to evolutionary adaptation. Screening a larger number of isolates, from different geographical origins and environments, should clarify the relationships between genetic diversity, morphology, and physiology in this important species.
    背景与目标: :扩增片段长度多态性(AFLP)分析用于研究葡萄牙蛇纹石和非蛇纹石土壤中的外生菌根真菌Cenococcum geophilum分离株的遗传多样性。在嗜水梭状芽孢杆菌分离物中发现了高度的遗传多样性。 AFLP指纹图谱显示所有分离株在基因上都是不同的。我们还评估了三种蛇形分离株和一种非蛇形分离株的体外镍敏感性。在生长培养基中添加镍只会显着影响非蛇纹石分离株。在30 microg g(-1)Ni下,放射状生长速率和生物量积累分别降至对照的73.3和71.6%,这是一个非常显着的抑制作用。此浓度的镍对蛇纹石分离物没有明显的抑制作用,因此,通过径向生长速率和生物量产量评估,蛇纹石分离物的适应性很可能不受田间镍的影响。在所有分离物中,菌丝体中的镍浓度随着生长培养基中镍浓度的增加而增加,但是鉴定出两种镍积累曲线。一种蛇形分离株显示出镍积累的线性趋势。在最高的Ni暴露水平下,此分离株菌丝体中的Ni浓度在高聚植物的累积范围内。在其余的分离物中,Ni的积累不那么明显,并且似乎在30 microg g(-1)Ni时接近平稳状态。由于在我们对镍不敏感的蛇形分离株中出现了两个镍积累曲线,因此该结果表明可能存在不同的镍解毒途径。在基因分析中,其生长受到镍显着影响的非蛇形分离株与其他分离株是分离的,这为镍敏感性特征提供了遗传基础。所有分离物均保持在不添加镍以避免残留效应的培养基上的事实进一步支持了该假设。但是,由于AFLP分析无法区分蛇纹石和非蛇纹石分离株,因此我们不能得出结论,我们的蛇纹石分离株中Ni不敏感是由于进化适应。筛选来自不同地理起源和环境的大量分离株,应阐明该重要物种的遗传多样性,形态和生理之间的关系。
  • 【使用推定的无性真菌Cenococcum geophilum作为模型,使用来自多个基因座的序列数据测试物种概念如何影响重组分析。】 复制标题 收藏 收藏
    DOI:10.1007/s00294-007-0150-1 复制DOI
    作者列表:Douhan GW,Martin DP,Rizzo DM
    BACKGROUND & AIMS: :Recent studies have found that three divergent lineages of the ectomycorrhizal fungus Cenococcum geophilum may co-occur within a single soil sample. To test how inference of population structure is affected by species concept, potential recombination in this putative asexual fungus was analyzed by sequencing 10 loci from 44 isolates from within one main lineage that is potentially sub-divisible into two phylogenetic species (A and B). Phylogenetic incongruence between these loci and recombination analyses using six different methods was consistent with recombination. However, most of the incongruence was caused by an apparently reciprocal recombination event between the actin locus and the other loci studied. Extreme divergence between the two types of actin loci suggests either an ancient recombination event or a more recent horizontal inheritance. We also found that random mating could not be rejected when A and B isolates were treated as members of a single species based on multilocus disequilibrium analyses, whereas random mating was rejected when all isolates were pooled. These results are significant and demonstrate that inferences of population structure can be confounded when isolates are pooled together based entirely on a morphological species concept.
    背景与目标: :最近的研究发现,在单个土壤样品中可能会同时存在三种外生菌根真菌Ceococcum geophilum的不同谱系。为了测试种群结构的推断如何受到物种概念的影响,通过对来自一个主要谱系中44个分离株的10个基因座进行测序,分析了该推定无性真菌中的潜在重组,该潜在株可能被细分为两个系统发育物种(A和B)。这些位点与使用六种不同方法进行的重组分析之间的系统发育不一致与重组是一致的。但是,大多数不一致之处是由肌动蛋白基因座和其他研究基因座之间的显然是相互的重组事件引起的。两种类型的肌动蛋白基因座之间的极端分歧暗示了古老的重组事件或更近的水平遗传。我们还发现,基于多基因座不平衡分析,当将A和B分离株视为单个物种的成员时,不能拒绝随机交配,而将所有分离株合并时,则拒绝随机交配。这些结果是有意义的,证明了当完全基于形态物种概念将分离株汇集在一起​​时,种群结构的推论可能会混淆。
  • 【由霉菌真菌球状芽孢杆菌产生的抗生素。】 复制标题 收藏 收藏
    DOI:10.1139/m64-049 复制DOI
    作者列表:KRYWOLAP GN,CASIDA LE Jr
    BACKGROUND & AIMS:
    背景与目标:
  • 【高寒针叶树针叶树定殖的变异性及其对针叶树的生态生理意义。】 复制标题 收藏 收藏
    DOI:10.1111/j.1469-8137.2005.01275.x 复制DOI
    作者列表:Hasselquist N,Germino MJ,McGonigle T,Smith WK
    BACKGROUND & AIMS: :* Plants establishing in environments that are marginal for growth could be particularly sensitive to mycorrhizal associations. We investigated ectomycorrhizal colonization and its significance for young conifers growing at, or above, their normal limits for growth, in the alpine-treeline ecotone. * Colonization of seedlings (<1 yr old) and juveniles (2- to 10-yr-old) of Picea engelmannii and Abies lasiocarpa by Cenococcum geophilum was determined in a field study, and effects of Cenococcum on Picea seedling ecophysiology were investigated in a glasshouse. * Colonization by Cenococcum was c. 20-fold greater for juveniles than seedlings, and approximately 4-fold greater adjacent compared with approximately 7 m away from trees. Juveniles of Picea were more colonized at timberline than Abies, and the opposite relationship was observed in forest. Colonization enhanced seedling water potential, but not phosphorus concentrations or photosynthesis. * These landscape and age-dependent variations in colonization correspond well with known variations in conifer physiology and establishment near timberline. Facilitation of seedling establishment by older trees at alpine-treeline may include a below-ground, mycorrhizal component that complements previously reported effects of trees on the microclimate and ecophysiology of seedlings.
    背景与目标: :*在生长边缘的环境中建立的植物可能对菌根协会特别敏感。我们调查了在高寒乔木过渡带中外生菌根定植及其对年轻针叶树达到或超过其正常生长极限的意义。 *在野外研究中确定了Cenococcum geophilum对青海云杉和小冷杉(Abies lasiocarpa)的幼苗(<1岁)和幼体(2至10岁)的定殖,并在A.温室。 * Cenococcum的殖民地为c。幼树比幼苗大约高20倍,而与之相比,相距树大约7 m,则其邻近部分大约大4倍。青云杉的幼虫在林线的居群多于冷杉,而在森林中则观察到相反的关系。定殖提高了幼苗的水势,但没有提高磷的浓度或光合作用。 *殖民地中这些与景观和年龄有关的变异与针叶林生理和林线附近树种的已知变异非常吻合。高龄树木在高山林木处促进幼苗生长可能包括地下的菌根成分,该成分补充了先前报道的树木对幼苗微气候和生态生理的影响。
  • 【外生菌根子囊孢子粒状葡萄糖利用葡萄糖期间甘露醇循环和海藻糖合成的C核磁共振研究。】 复制标题 收藏 收藏
    DOI:10.1104/pp.77.2.499 复制DOI
    作者列表:Martin F,Canet D,Marchal JP
    BACKGROUND & AIMS: :(13)C nuclear magnetic resonance spectroscopy has been used to follow the utilization of glucose for the synthesis of carbohydrates in the ectomycorrhizal ascomycete Cenococcum graniforme. The fate of (13)C label was analyzed in vivo and in mycelial extracts. The major carbohydrates produced from [1-(13)C]glucose and [6-(13)C]glucose were mannitol and trehalose. Mannitol was mainly synthesized via a direct route from glucose. Scrambling of the (13)C label was observed to occur in trehalose during glycolysis. From the analysis of the scrambling patterns, it is concluded that the mannitol cycle was operative and that a large part of the carbon of glucose was used to form trehalose after cycling through the mannitol pool. The activities of NAD-mannitol-l-P dehydrogenase (EC 1.1.1.17) and NADP-mannitol dehydrogenase (EC 1.1.1.138), which participate in the mannitol cycle relative to the activity of glycolytic enzymes, provide evidence that the cycle is important for NADPH production.
    背景与目标: :(13)C核磁共振波谱已被用于跟踪葡萄糖的利用,以在外生菌根的子囊Cenococcum graniforme中合成碳水化合物。 (13)C标签的命运在体内和菌丝体提取物中进行了分析。由[1-(13)C]葡萄糖和[6-(13)C]葡萄糖产生的主要碳水化合物是甘露醇和海藻糖。甘露醇主要通过直接途径由葡萄糖合成。观察到(13)C标记在糖酵解过程中发生在海藻糖中。通过对加扰模式的分析,可以得出结论,甘露醇循环是有效的,并且在循环通过甘露醇池后,葡萄糖的大部分碳用于形成海藻糖。相对于糖酵解酶的活性,参与甘露醇循环的NAD-甘露醇-1P脱氢酶(EC 1.1.1.17)和NADP-甘露醇脱氢酶(EC 1.1.1.138)的作用提供了证据,表明该循环对NADPH很重要生产。
  • 【外生菌根生态学被印在占优势的共生真菌Cenococcum geophilum的基因组中。】 复制标题 收藏 收藏
    DOI:10.1038/ncomms12662 复制DOI
    作者列表:
    BACKGROUND & AIMS: :The most frequently encountered symbiont on tree roots is the ascomycete Cenococcum geophilum, the only mycorrhizal species within the largest fungal class Dothideomycetes, a class known for devastating plant pathogens. Here we show that the symbiotic genomic idiosyncrasies of ectomycorrhizal basidiomycetes are also present in C. geophilum with symbiosis-induced, taxon-specific genes of unknown function and reduced numbers of plant cell wall-degrading enzymes. C. geophilum still holds a significant set of genes in categories known to be involved in pathogenesis and shows an increased genome size due to transposable elements proliferation. Transcript profiling revealed a striking upregulation of membrane transporters, including aquaporin water channels and sugar transporters, and mycorrhiza-induced small secreted proteins (MiSSPs) in ectomycorrhiza compared with free-living mycelium. The frequency with which this symbiont is found on tree roots and its possible role in water and nutrient transport in symbiosis calls for further studies on mechanisms of host and environmental adaptation.
    背景与目标: :在树根上最常遇到的共生菌是子囊夜蛾Cenococcum geophilum,它是最大的真菌类Dothideomycetes中唯一的菌根物种,该类真菌以破坏性植物病原体而闻名。在这里,我们显示外生菌根的担子菌的共生基因组特质也存在于地衣梭状芽胞杆菌中,具有共生作用诱导的,分类功能特异性基因,功能未知,植物细胞壁降解酶的数量减少。地衣梭状芽胞杆菌仍持有已知与发病机理有关的类别中的大量基因,并且由于转座因子的增殖而显示出增加的基因组大小。与自由活动菌丝体相比,转录物谱分析显示膜转运蛋白(包括水通道蛋白水通道和糖转运蛋白)以及菌根诱导的小生菌根中小分泌蛋白(MiSSPs)的膜上调显着上调。在树根上发现这种共生体的频率及其在共生中水和养分运输中的可能作用,要求进一步研究寄主和环境适应机制。

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