Ankrd17, an ubiquitously expressed ankyrin factor, is essential for the vascular integrity during embryogenesis

Ankyrin repeat domain 17 (Ankrd17) encodes an ubiquitously expressed protein with two clusters of ankyrin repeats. We have used gene targeting strategy to ablate the Ankrd17 gene in mouse. The Ankrd17-deficient mice died between embryonic day (E) 10.5 and E11.5 due to cardiovascular defects. Serious hemorrhages were detected and the vascular smooth muscle cells (vSMCs) surrounding the vessels were drastically reduced in the Ankrd17-deficient embryos, suggesting that the vascular maturation was not completed. Interestingly, vSMC differentiation marker genes were up-regulated in the mutant embryos. Our data have demonstrated the indispensability of Ankrd17 functioning for vascular maturation during early development. The Ankrd17-deficient mice also provide a new animal model for the analysis of the regulatory pathways of the differentiation of vSMC precursor cells.     

Ubiquitin ligase Cbl-b sensitizes leukemia and gastric cancer cells to anthracyclines by activating the mitochondrial pathway and modulating Akt and ERK survival signals

The present study reported that the ubiquitin ligase Cbl-b was up-regulated during anthracycline-induced apoptosis in two cell lines, RBL-2H3 leukemia cells and MGC803 gastric cancer cells. Overexpression of Cbl-b strongly promoted the cytotoxic and apoptosis-inducing effects of anthracyclines, while a dominant negative (DN) Cbl-b mutation abolished these effects in both cell lines. Further investigation revealed that mitochondrial depolarization was enhanced by Cbl-b and decreased by Cbl-b (DN) in RBL-2H3 cells. Moreover, overexpression of Cbl-b significantly suppressed ERK activation, and Cbl-b (DN) strongly enhanced both ERK and Akt activation. Altogether, these results indicate that Cbl-b sensitized both leukemia and gastric cancer cells to anthracyclines by activating the mitochondrial apoptotic pathway and modulating the ERK and Akt survival pathways.     

Lophodermium pini-mugonis sp. nov. on needles of Pinus mugo from the Alps based on morphological and molecular data

Lophodermium pini-mugonis, collected on needles of Pinus mugo from German Alps, is described as a species new to science. It is characterized by subcuticular ascomata with a wrinkled surface and a somewhat untidy outline, a complex structure of lip cells, and ellipsoidal conidia. An analysis of the internal transcribed spaces of rDNA showed that Lophodermium pini-mugonis is, sister to Lophodermium autumnale and distantly related to other Lophodermium species on pines. The hypothesis of cospeciation of Lophodermium species with members of the Pinaceae is discussed.     

Interaction between a dark septate endophytic isolate from Dendrobium sp. and roots of D. nobile seedlings

Interactions between an isolate of dark septate endophytas (DSE) and roots of Dendroblum nobile Lindl.seedlings are reported in this paper.The isolate was obtained from orchid mycorrhizas on Dendrobium sp.in subtropical forest.The fungus formed typical orchid mycorrhiza in aseptic co-culture with D.nobile seedlings on modified Murashige-Skoog (MMS)medium.Anatomic observations of the infected roots showed that the DSE hyphae invaded the velamen layer,passed through passage cells in exodermis,entered the cortex cells,and then formed fungal pelotons of orchid mycorrhiza.D.nobile seedlings' plant height,stem diameter,new roots number and biomass were greatly enhanced by inoculating the fungus to seedlings.The fungus was identified as Leptodontidium by sequencing the polymerase chain reaction-amplified rDNA ITSt-5.8S-ITS2 (internal transcribed spacer (ITS)) regions and comparison with similar taxa.     

The construction of a genetic linkage map of non-heading Chinese cabbage （Brassica campestris ssp. chinensis Makino）

Non-heading Chinese cabbage （Brassica carnpestris ssp. chinensis Makino） is one of the most important vegetables in eastern China. A genetic linkage map was constructed using 127 doubled haploid （DH） lines, and the DH population was derived from a commercial hybrid ＂Hanxiao＂ （lines SW-13 x L-118）. Out of the 614 polyrnorphic markers, 43.49% were not assigned to any of the linkage groups （LGs）. Chi-square tests showed that 42.67% markers were distorted from expected Mendelian segregation ratios, and the direction of distorted segregation was mainly toward the paternal parent L-118. After sequentially removing the markers that had an interval distance smaller than 1 cM from the upper marker, the overall quality of the linkage map was increased. Two hundred and sixty-eight molecular markers were mapped into 10 LGs, which were anchored to the corresponding chromosome of the B. rapa reference map based on com- mon simple sequence repeat （SSR） markers. The map covers 973.38 cM of the genome and the average interval distance between markers was 3.63 cM. The number of markers on each LG ranged from 18 （R08） to 64 （R07）, with an average interval distance within a single LG from 1.70 cM （R07） to 6.71 cM （R06）. Among these mapped markers, 169 were sequence-related amplified polymorphism （SRAP） molecular markers, 50 were SSR markers and 49 were random amplification polymorphic DNA （RAPD） markers. With further saturation to the LG9 the current map offers a genetic tool for loci analysis for important agronomic traits.     

拟南芥 MeIAA 抗性突变体的筛选和初步图位克隆分析

生长素是最重要的植物激素之一, 参与了植物生长发育的各个方面。植物体内游离的IAA是生长素的主要活性形式, 在IAA甲基转移酶1(IAMT1)的作用下, IAA可以转变为IAA甲酯 (MeIAA)。MeIAA本身没有活性, 在植物体内的MeIAA酯解酶作用下可以重新转变为IAA。 MeIAA是非极性分子, 能够在植物体内自由扩散。利用MeIAA的这种特殊性质筛选突变体, 可以分离到MeIAA代谢途径或者IAA途径中新的成分。我们对拟南芥种子进行EMS诱变, 通过观察黑暗下下胚轴的生长情况, 筛选MeIAA的抗性突变体。我们成功分离到了8株可能的抗性突变体, 并对其中的一个Methyl -IAA resistant 1 (mir1) 突变体进行了深入分析。MeIAA抗性突变体的筛选将为进一步了解MeIAA的代谢、IAA稳态调控和响应机理提供新的材料。     

Effect of slow-release urea on soil nematode community structure in a Chinese soybean field

The effect of slow-release urea on soil nematode community structure was investigated in a soybean field in northeast China.Three treatments,no urea (CK),conventional urea (U) and slow-release urea (SRU),were arranged in a completely random design.The results show that the abundance of total nematodes was significantly higher in SRU than in CK and U.Significant differences in the abundance of bacterivores with colonizer-persister (cp) values 2-3,fungivores with cp 2 and herbivores with cp 3 were found among different treatments.Forty-one genera were identified,of which Acrobeloides,Aphelenchus and Heterodera were dominant.Soil nematode guilds and genera exhibited different responses to slow-release urea.The most trophic groups and genera had greater abundances in SRU than in CK and U.Slow-release urea had a positive effect on soil nematode community structure.