Evolution of North American PVYNTN Strain Tu 660 from Local PVYN by Mutation rather than Recombination

A North American (NA) isolate of tobacco veinal necrotic strain of Potato virus Y (PVY^N) (N-Jg) and a NA isolate of potato tuber necrotic strain of Potato virus Y (PVY^NTN) (Tu 660) were tested for their phenotypes by inoculation to potato plants of three potato cultivars. Upon inoculation with Tu 660, tubers of the cultivars Norchip and Ranger Russet developed potato tuber necrotic ringspot disease (PTNRD) but not the tubers of Russet Burbank. N-Jg failed to induce PTNRD in the tested cultivars. The genomic RNAs of both strains were completely sequenced and analysed. High homology (98% and 99% identity on nucleotide and polyprotein, respectively) was found between Tu 660 and N-Jg. When polyproteins were compared with other isolates, high identity was observed between Tu 660 and an European (Eu) PVY^N-605 (98%) and with an Eu-PVY^NTN-H (96%). However, when individual mature proteins were compared, much lower identities (86.5–94%) were found between Tu 660 and PVY^NTN-H compared to 98–99.5% between Tu 660 and PVY^N-605 in the P3, 6K1 and CI regions. Further sequence analysis indicated that the PVY^NTN-H is a hybrid molecule of the genomic RNA recombination of PVY^O and Eu-PVY^N as shown by Glais et al. (Arch Virol 147, 363–378), whereas NA-PVY^NTN Tu 660 is free of recombination points. Phylogenetic analysis confirmed this observation, and suggested that, in light of high homology, the Tu 660 might have evolved from NA-PVY^N by mutations rather than the genome recombinations. The non-recombinant nature of NA-PVY^NTN Tu 660 strongly suggests that the recombinant structure of genome is not a necessary prerequisite for the PTNRD phenotype.     

Tandem chromosome fusions in karyotypic evolution of Muntiacus: evidence from M. feae and M. gongshanensis

The muntjacs (Muntiacus, Cervidae) are famous for their rapid and radical karyotypic diversification via repeated tandem chromosome fusions, constituting a paradigm for the studies of karyotypic evolution. Of the five muntjac species with defined karyotypes, three species (i.e. Muntiacus reevesi, 2n = 46; M. m. vaginalis, 2n = 6/7; and M. crinifrons, 2n = 8/9) have so far been investigated by a combined approach of comparative chromosome banding, chromosome painting and BAC mapping. The results demonstrated that extensive centromere–telomere fusions and a few centric fusions are the chromosomal mechanisms underlying the karyotypic evolution of muntjacs. Here we have applied the same approach to two additional muntjac species with less well-characterized karyotypes, M. feae (2n = 14♂) and M. gongshanensis (2n = 8♀). High-resolution G-banded karyotypes for M. feae and M. gongshanensis are provided. The integrated analysis of hybridization results led to the establishment of a high-resolution comparative map between M. reevesi, M. feae, and M. gongshanensis, proving that all tandem fusions underpinning the karyotypic evolution of these two muntjac species are also centromere–telomere fusions. Furthermore, the results have improved our understanding of the karyotypic relationships of extant muntjac species and provided compelling cytogenetic evidence that supports the view that M. crinifrons, M. feae, and M. gongshanensis should each be treated as a distinct species.     

单侧外周伤害性刺激诱发大鼠脊髓中转录因子CREB的双侧磷酸化(英文)

c AMP反应成分结合蛋白 (c AMP response elem ent-binding protein,CREB)是一种转录因子 ,它在磷酸化之后可调节靶基因的转录。 CREB在 13 3位置的丝氨酸的磷酸化 ,与脊髓中伤害性传入的处理有关 ,本文作者等用特殊抗体对此进行了免疫细胞化学研究。在正常大鼠 ,虽然几乎所有脊髓神经元的核中都可见 CREB的轻度着色 ,但磷酸化的 CREB仅见于双侧腰段脊髓的 ～ 层 (75± 15 vs60± 18)和 层 (9± 3 )。用福尔马林注射引起一侧后脚掌出现炎症时 ,可在双侧腰段脊髓看到磷酸化CREB细胞核的快速 (小于 5 min)和节段性的显著增多 ;它们主要分布在双侧背角表层 ～ 层 (2 5 4± 2 0 vs 2 62± 2 3 )、 层(115± 13 )和双侧 ～ 层 (3 46± 2 0 vs3 2 8± 2 6) ;而在对照和炎症组大鼠的胸段脊髓中均未见磷酸化 CREB的增加。在注射CFA诱发一侧炎症或切断一侧坐骨神经的实验组大鼠 ,也可看到至少延续到第三天的强而双侧性的 CREB的磷酸化。这种由一侧后肢伤害性传入引致腰段脊髓中镜像式双侧 CREB磷酸化的出现 ,与一般看到的损伤传入只在同侧脊髓背角引起某些神经化学改变的结果不同 ,可能是人神经损伤后或在实验动物中出现对侧镜像式疼痛过敏现象的基础     

A Novel Deep Learning Model Based on Multi-Scale and Multi-View for Detection of Pulmonary Nodules

Journal of Digital Imaging - Lung cancer manifests as pulmonary nodules in the early stage. Thus, the early and accurate detection of these nodules is crucial for improving the survival rate of...     

自能源减速器称重动态过程的仿真研究

对自能源减速器称重过程的动态性能进行机理研究,建立了称重动态过程的数学模型,并进行了仿真计算,仿真结果与实测吻合.在此基础上分析了溜放速度、容腔及管路内油液的可压缩性对称重结果的影响.首次提出了"完全称重"、"部分称重"、"重复称重"的概念,为减速顶的设计提供新的理论依据.     

HPLC法测定阿奇霉素的血药浓度

目的 :建立阿奇霉素血药浓度的测定方法。方法 :采用HPLC紫外检测法 ,岛津CLC CN分析柱 ,流动相为 0 1mol·L-1磷酸二氢钠 甲醇 乙腈 ( 85∶7∶8,,V/V/V) ,pH 3 0～ 3 5 ,流速 1mL·min-1,柱温 4 0℃ ,检测波长 2 10nm ,灵敏度 0 0 0 3AUFS ,提取液为氯仿 正己烷 ( 3∶2 ,V/V) ,以峰面积外标法定量。结果 :阿奇霉素血药浓度线性范围 5 0～ 5 0 0 0 μg·L-1,平均回收率( 10 0 9± 2 7) % ,日内RSD 1 2 %～ 4 3% ,日间RSD 2 8%～ 6 8%。结论 :本法简便 ,分析速度快 ,灵敏度较高 ,重复性好 ,基本能适用于临床血药浓度测定及药动学研究。     

深圳市孕妇地中海贫血产前筛查及产前诊断

目的：调查深圳市孕妇地中海贫血发病率、基因突变类型，对高风险胎儿进行产前诊断。方法：1998年1月至2002年12月采用二步法对产前检查的4136例孕妇进行地中海贫血筛查。结果：检出地中海贫血阳性病例297例，发病率7．18％，其中。地中海贫血阳性病例172例，发病率4．16％；β地中海贫血阳性病例125例，发病率3．02％。229例被确定了基因型。对19对夫妇均为地中海贫血携带者胎儿进行产前基因诊断，确定正常胎儿3例，α1地中海贫血杂合子4例，β地中海贫血杂合子8例，Bart‘S水肿胎儿2例，β地中海贫血双重杂合子2例。结论：通过产前筛查地中海贫血，确诊重症患儿及时终止妊娠，可有效地避免重症患儿的出生。