Research advances in the Pyrenophora teres–barley interaction

Pyrenophora teres f. teres and P. teres f. maculata are significant pathogens that cause net blotch of barley. An increased number of loci involved in P. teres resistance or susceptibility responses of barley as well as interacting P. teres virulence effector loci have recently been identified through biparental and association mapping studies of both the pathogen and host. Characterization of the resistance/susceptibility loci in the host and the interacting effector loci in the pathogen will provide a path for targeted gene validation for better-informed release of resistant barley cultivars. This review assembles concise consensus maps for all loci published for both the host and pathogen, providing a useful resource for the community to be used in pathogen characterization and barley breeding for resistance to both forms of P. teres.     

基于低相干光干涉的眼睛光学生物参数测量研究

目的 眼睛的光学生物参数中的眼轴长度(AL)和角膜曲率半径(CR)可以作为预防和监测眼球近视的两个重要参数。为了提高测量眼轴长度的速度与精度和同步实现角膜曲率高精度动态测量,本文提出一种基于低相干光干涉技术眼睛光学生物参数测量的系统。方法 该系统使用旋转光学延迟线快速改变参考光的光程,利用曲率半径为8 mm的标准件标定人眼角膜顶点到靶环之间的距离,利用角膜的干涉信号对相机和数据采集卡进行触发实现同步采集,从而实现眼轴长度的快速测量和精准定位靶环到角膜顶点之间的距离,同时保证成像系统的放大倍率恒定和数据的实时采集。结果 实验结果表明,这种低相干光干涉测量系统,可以实时测量眼轴长度和角膜曲率半径,眼轴长度误差低于40μm,人眼角膜曲率半径方差为2.082 36×10^-2μm。结论 该系统能够快速、精准地测量AL和CR,可在近视的预防和监测中发挥重要作用。     

西安地区现代人前臂骨的人类学研究

关于桡骨和尺骨的研究,国外资料较多。Stewart(1952)、Martin(1959)分别集中并分析了世界不同地区、人种和民族的数值。然而,国内有关桡、尺骨的研究资料尚不多见,而较为系统地从人类学角度进行的研究,作者仅看到赵一清(1957)的系统资料。本文就西安地区现代人前臂骨的形态进行线性和有关角度的测量,并计算了桡骨、尺骨的有关指数,分析了这些数值的性差、侧差和地区差异。从而,一方面为国人体质人类学补充新资料,同时又为临床与法医学等方面的实际应用提供参考数据。     

Population genetics of two rare perennials in isolated wetlands: Sagittaria isoetiformis and S. teres (Alismataceae)

We investigated genetic structure in two closely related perennial plants that occur in isolated wetlands: Sagittaria isoetiformis, restricted to the southeastern Coastal Plain of North America, and S. teres, endemic to the northeastern Coastal Plain. Using horizontal starch-gel electrophoresis, we screened 527 individuals from 11 populations of S. isoetiformis and 367 individuals from seven populations of S. teres. A high proportion of the 16 loci were polymorphic (%P(S) = 93.8% in S. isoetiformis and %P(S) = 75.0% in S. teres), with higher mean numbers of alleles per polymorphic locus and effective alleles per locus in S. isoetiformis (AP = 3.27, A(E) = 1.90) than in S. teres (AP = 2.58, A(E) = 1.30). Species- and population-level expected heterozygosities were higher in S. isoetiformis (H(ES) = 0.399, H(EP) = 0.218) than in S. teres (H(ES) = 0.177, H(EP) = 0.101). Jackknife estimates of F statistics indicated moderate levels of inbreeding in S. teres (F(IS) = 23.1%). Strong differentiation characterized these geographically isolated populations (G(ST) = 39.9% in S. isoetiformis, and G(ST) = 26.1% in S. teres). Genetic identities varied substantially within (ī = 75%, range = 0.558-0.963 in S. isoetiformis; ī = 89%, range = 0.776-0.963 in S. teres) and among species (ī = 81%, range = 0.506-0.882), leading to the discrimination of four regional population clusters using nonmetric multidimensional scaling (NMDS). It appears that S. isoetiformis and S. teres are a progenitor-derivative species pair.     

Genotype‐by‐sequencing of the plant‐pathogenic fungi Pyrenophora teres and Sphaerulina musiva utilizing Ion Torrent sequence technology

Genetic and genomics tools to characterize host–pathogen interactions are disproportionately directed to the host because of the focus on resistance. However, understanding the genetics of pathogen virulence is equally important and has been limited by the high cost of de novo genotyping of species with limited marker data. Non‐resource‐prohibitive methods that overcome the limitation of genotyping are now available through genotype‐by‐sequencing (GBS). The use of a two‐enzyme restriction‐associated DNA (RAD)‐GBS method adapted for Ion Torrent sequencing technology provided robust and reproducible high‐density genotyping of several fungal species. A total of 5783 and 2373 unique loci, ‘sequence tags’, containing 16 441 and 9992 single nucleotide polymorphisms (SNPs) were identified and characterized from natural populations of Pyrenophora teres f. maculata and Sphaerulina musiva, respectively. The data generated from the P. teres f. maculata natural population were used in association mapping analysis to map the mating‐type gene to high resolution. To further validate the methodology, a biparental population of P. teres f. teres, previously used to develop a genetic map utilizing simple sequence repeat (SSR) and amplified fragment length polymorphism (AFLP) markers, was re‐analysed using the SNP markers generated from this protocol. A robust genetic map containing 1393 SNPs on 997 sequence tags spread across 15 linkage groups with anchored reference markers was generated from the P. teres f. teres biparental population. The robust high‐density markers generated using this protocol will allow positional cloning in biparental fungal populations, association mapping of natural fungal populations and population genetics studies.     

Mitochondrial DNA reveals different phylogeographic structures in the water shrews Neomys anomalus and N. fodiens (Insectivora: Soricidae) in Europe

We studied the intraspecific genetic variation of 17 Neomys anomalus (Cabrera, 1907) (eight localities) and 24 Neomys fodiens (Pennant, 1771) (nine localities) in Europe. As molecular marker, we used the sequences of the mtDNA gene for cytochrome b (1140 bp from 24 specimens; 272 bp from 15 specimens). The phylogenetic analysis of N. fodiens shows slight divergence among haplotypes, with only one supported clade including two geographically distant haplotypes from Calabria (southern Italy) and Pyrenees (France); these haplotypes diverge from the others by 2.9% and 2.1%, respectively. In N. anomalus , one haplotype from Spain is very different, diverging from all others by 8–10% of the sequence. This level of divergence is similar to that found between N. anomalus and another species, Neomys teres . There are two other supported clades in N. anomalus , an Italian subclade and an eastern subclade comprising haplotypes from Turkey and Slovenia. Moreover, we found a different genetic structure between the two species with greater divergence in N. anomalus than in N. fodiens. The phylogeographic patterns are discussed in a temporal framework and considering the different ecological characteristics of these two species.     

超薄前臂皮瓣在鼻部缺损的应用

目的：探讨超薄前臂皮瓣修复鼻部缺损的临床效果,为临床治疗提供依据。方法：回顾性分析我院于2007年1月~2010年12月收治鼻颌面部缺损患者16例,观察患者皮瓣的成活率和并发症发生等情况。结果：超薄前臂皮瓣移植组皮辫成活率为100％,住院天数为（21．5±6．5）d,无并发症发生。16例患者随访6个月~2年,无失访。皮瓣颜色与面部正常皮肤接近,厚度适中,鼻部外形满意。同时前臂切口瘢痕不明显,皮肤感觉无异常。结论：超薄前臂皮瓣在鼻部缺损修复中成活率更高,患者康复快,并发症较少,值得临床推广使用。