Identification of genome-wide variations among three elite restorer lines for hybrid-rice

Rice restorer lines play an important role in three-line hybrid rice production. Previous research based on molecular tagging has suggested that the restorer lines used widely today have narrow genetic backgrounds. However, patterns of genetic variation at a genome-wide scale in these restorer lines remain largely unknown. The present study performed re-sequencing and genome-wide variation analysis of three important representative restorer lines, namely, IR24, MH63, and SH527, using the Solexa sequencing technology. With the genomic sequence of the Indica cultivar 9311 as the reference, the following genetic features were identified: 267,383 single-nucleotide polymorphisms (SNPs), 52,847 insertion/deletion polymorphisms (InDels), and 3,286 structural variations (SVs) in the genome of IR24; 288,764 SNPs, 59,658 InDels, and 3,226 SVs in MH63; and 259,862 SNPs, 55,500 InDels, and 3,127 SVs in SH527. Variations between samples were also determined by comparative analysis of authentic collections of SNPs, InDels, and SVs, and were functionally annotated. Furthermore, variations in several important genes were also surveyed by alignment analysis in these lines. Our results suggest that genetic variations among these lines, although far lower than those reported in the landrace population, are greater than expected, indicating a complicated genetic basis for the phenotypic diversity of the restorer lines. Identification of genome-wide variation and pattern analysis among the restorer lines will facilitate future genetic studies and the molecular improvement of hybrid rice.     

p53-mediated activation of the mitochondrial protease HtrA2/Omi prevents cell invasion

Oncogenic Ras induces cell transformation and promotes an invasive phenotype. The tumor suppressor p53 has a suppressive role in Ras-driven invasion. However, its mechanism remains poorly understood. Here we show that p53 induces activation of the mitochondrial protease high-temperature requirement A2 (HtrA2; also known as Omi) and prevents Ras-driven invasion by modulating the actin cytoskeleton. Oncogenic Ras increases accumulation of p53 in the cytoplasm, which promotes the translocation of p38 mitogen-activated protein kinase (MAPK) into mitochondria and induces phosphorylation of HtrA2/Omi. Concurrently, oncogenic Ras also induces mitochondrial fragmentation, irrespective of p53 expression, causing the release of HtrA2/Omi from mitochondria into the cytosol. Phosphorylated HtrA2/Omi therefore cleaves β-actin and decreases the amount of filamentous actin (F-actin) in the cytosol. This ultimately down-regulates p130 Crk-associated substrate (p130Cas)-mediated lamellipodia formation, countering the invasive phenotype initiated by oncogenic Ras. Our novel findings provide insights into the mechanism by which p53 prevents the malignant progression of transformed cells.     

马尾松雌球果的发生和早期发育研究

采用常规石蜡制片技术对马尾松雌球果的发生和早期发育进行了研究。结果表明：雌球果原基发生时间为10月中旬,不同的树龄和着生部位,其发生时间不同。雌球果原基与营养茎端在外部形态及内部细胞组织学分区结构有明显差异。营养茎端外形扁平,内部顶端分生组织结构有顶端原始细胞区、中央母细胞区、形成层状过渡区、周围分生组织区及肋状分生组织区5个明显的分区;而雌球果原基外形呈圆锥状,内部结构只有套层和髓区。12月初,最初的苞片原基在雌球果原基的鳞片的叶腋处产生,之后其由基部向顶部连续发生。翌年1月初,在苞片原基的叶腋处,珠鳞原基发生,发生方向亦为向顶发育。2月底,苞片体积不再发生变化,珠鳞膨大端的基部的近轴面分化出2个倒生胚珠。从雌球果原基发生到胚珠分化历时4个多月。亚热带的冬季气候对马尾松雌球果的生长发育没有明显的抑制作用。     

代谢性谷氨酸受体配体(s)-4C3HPG对大鼠脑缺血耐受性诱导的影响

目的：观察侧脑室注射代谢型谷氨酸受体1／5亚型（mGluR1/5)配体（s)-4C3HPG对海马脑缺血耐受（BIT）诱导的影响,以探讨mGLUR1/5在BIT诱导中的作用。方法：采用大鼠四血管闭塞全脑缺血模型（4－vessel occlusion,4VO),应用硫堇染色和GFAP免疫组化法。36只大鼠椎动脉凝闭后分为sham组、单纯缺血组、BIT组和（s)-4C3HPG组,其中（s)-4C3HPG组又按所给药物剂量不同,分为0．2、0．04和0．008mg三个亚组。所有动物均在手术后或末次缺血后7d处死取材观察。结果：（1）单纯8min缺血可使海马CA1区组织学分级升高、锥体神经元密度降低和胶质纤维酸性蛋白（glial fibrillary acidic protein,GFAP)阳性表达增加（P＜0．05vs sham）.(2)BIT组未见单纯缺血组的上述变化,表明CIP可防止后续8min缺血造成的神经元损伤。（3）CIP的这种保护作用可被（s)-4C3HPG阻断,表现为海马CA1区组织学分级升高和锥体神经元密度降低（P＜0．05 vs sham)。这种变化与（s)-4C3HPG的剂量呈现明显的相关性,即剂量越大,上述改变越明显。结论：（s)-4C3HPG可阻断CIP诱导BIT的作用,提示mGluR1/5参与BIT的诱导。     

抗人肺腺癌单克隆抗体重,轻链可变区基因的分离克隆和序列测定

根据鼠免疫球蛋白重。轻链可变区基因ＦＲ１和ＦＲ４的序列保守性,化学合成了适于体外扩增Ｉｇ重、轻链可变区基因（Ｖ_Ｈ和Ｖ_Ｌ）的数对引物。以分泌抗人肺腺癌单抗的杂交瘤细胞株ＷＬＡ－２Ｃ４的基因组ＤＮＡ为模板,ＰＣＲ扩增Ｖ_Ｈ和Ｖ_Ｌ基因,分别克隆人ｐＵＣ１９载体。转化子经蓝、白斑筛选,酶切鉴定,双脱氧测序证实确为鼠单抗可变区基因,其中Ｖ_Ｈ基因全长为３４８ｂｐ,编码１１６ａａ,属重链ⅡＢ亚类;Ｖ_Ｌ基因全长３１８ｂｐ,编码１０６ａａ,属Ｋ轻链Ⅵ亚类。     

阿加曲班对MCAO大鼠不同时间点血小板功能的影响

建立大脑中动脉闭塞(model of middle cerebral artery occlusion,MCAO)大鼠模型,研究阿加曲班对大鼠不同时间脑缺血再灌注损伤血小板功能的影响。将120只健康雄性SD大鼠随机分为假手术组(Sham)、模型组(Model)和阿加曲班给药组(Argatroban),其中Argatroban组分为4组:Argatroban+30 min组、Argatroban+1 h组、Argatroban+3 h组和Argatroban+7 h组,Sham组和Model组40只,其余各组每组10只。线栓法制备大鼠MCAO模型,术中输注Argatroban,剂量为0.3μg·kg^-1·min^-1,完成手术前5 min停止输注。手术完成后,Sham组和Model组分别于术后30 min、1 h、3 h和7 h处死10只取样;Argatroban给药组5个时间点处死取样。检测大鼠血浆血细胞数量,并计数骨髓有核细胞数的变化。采用流式细胞仪检测血小板-白细胞聚集体(platelet-leukocyte aggregates,PLA)表达水平,观察活化部分凝血活酶时间(activated partial thromboplastin time,APTT)、血小板计数变化,ELISA检测血浆D-二聚体和TAT。结果显示,与Sham组相比,Model组大鼠的红细胞(RBC)、白细胞(WBC)、血红蛋白含量(HGB)和中性粒细胞(GR)数都显著升高(p<0.05),且与给药组没有统计学差异。Sham组、Model组和Argatroban给药组的骨髓有核细胞数也没有统计学差异。与Sham组相比,Model组PLA表达水平极显著升高(p<0.01),Argatroban+30 min组PLA表达水平却低于Sham组,但没有统计学差异,Argatroban+1 h组高于Sham组和Argatroban+30 min组(p<0.05),Argatroban+3 h组和Argatroban+7 h组高于Argatroban+1 h组低于Sham组。术后各组的血小板计数均高于Sham组(p<0.05),Argatroban各组的血小板计数要低于Model组(p<0.05),并在30 min时达到最低,30 min以后血小板升高,但是1 h以后血小板不再升高,趋于稳定。Argatroban各组PT和APTT虽略有降低,但是与Sham组和Model组并没有统计学差异。造模后各组TAT、D-二聚体水平显著升高,Argatroban各组TAT水平较模型组明显降低(p<0.05),Argatroban+30 min组水平最低。MCAO模型大鼠血液呈现高凝状态,凝血功能和纤维蛋白溶解功能亢进,血小板活化增强,阿加曲班可对此起到改善作用。     

S-Nitrosated human serum albumin dimer is not only a novel anti-tumor drug but also a potentiator for anti-tumor drugs with augmented EPR effects

Macromolecules have been developed as carriers of low-molecular-weight drugs in drug delivery systems (DDS) to improve their pharmacokinetic profile or to promote their uptake in tumor tissue via enhanced permeability and retention (EPR) effects. In the present study, recombinant human serum albumin dimer (AL-Dimer), which was designed by linking two human serum albumin (HSA) molecules with the amino acid linker (GGGGS)(2), significantly accumulated in tumor tissue even more than HSA Monomer (AL-Monomer) and appearing to have good retention in circulating blood in murine colon 26 (C26) tumor-bearing mice. Moreover, we developed S-nitrosated AL-Dimer (SNO-AL-Dimer) as a novel DDS compound containing AL-Dimer as a carrier, and nitric oxide (NO) as (i) an anticancer therapeutic drug/cell death inducer and (ii) an enhancer of the EPR effect. We observed that SNO-AL-Dimer treatment induced apoptosis of C26 tumor cells in vitro, depending on the concentration of NO. In in vivo experiments, SNO-AL-Dimer was found to specifically deliver large amounts of cytotoxic NO into tumor tissue but not into normal organs in C26 tumor-bearing mice as compared with control (untreated tumor-bearing mice) and SNO-AL-Monomer-treated mice. Intriguingly, S-nitrosation improved the uptake of AL-Dimer in tumor tissue through augmenting the EPR effect. These data suggest that SNO-AL-Dimer behaves not only as an anticancer therapeutic drug, but also as a potentiator of the EPR effect. Therefore, SNO-AL-Dimer would be a very appealing carrier for utilization of the EPR effect in future development of cancer therapeutics.     

Detection of quantitative trait loci for growth- and fatness-related traits in a large-scale White Duroc × Erhualian intercross pig population

Growth and fatness are economically important traits in pigs. In this study, a genome scan was performed to detect quantitative trait loci (QTL) for 14 growth and fatness traits related to body weight, backfat thickness and fat weight in a large-scale White Duroc × Erhualian F(2) intercross. A total of 76 genome-wide significant QTL were mapped to 16 chromosomes. The most significant QTL was found on pig chromosome (SSC) 7 for fatness with unexpectedly small confidence intervals of ～2 cM, providing an excellent starting point to identify causal variants. Common QTL for both fatness and growth traits were found on SSC4, 5, 7 and 8, and shared QTL for fat deposition were detected on SSC1, 2 and X. Time-series analysis of QTL for body weight at six growth stages revealed the continuously significant effects of the QTL on SSC4 at the fattening period and the temporal-specific expression of the QTL on SSC7 at the foetus and fattening stages. For fatness traits, Chinese Erhualian alleles were associated with increased fat deposition except that at the major QTL on SSC7. For growth traits, most of White Duroc alleles enhanced growth rates except for those at three significant QTL on SSC6, 7 and 9. The results confirmed many previously reported QTL and also detected novel QTL, revealing the complexity of the genetic basis of growth and fatness in pigs.     

Effects of toxic β‐glucosides on carbohydrate metabolism in cotton bollworm,Helicoverpa armigera (Hübner)

The purpose of this study was to evaluate the effects of three toxic β‐glucosides, phlorizin, santonin, and amygdalin, on carbohydrate metabolism in the cotton bollworm, Helicoverpa armigera (Hübner), when diets mixed with β‐glucosides were fed to third‐instar larvae. The growth of the larvae was significantly inhibited by exposure to santonin after 96 hr but not obviously affected by phlorizin and amygdalin. The midgut trehalase activities were only 51.7%, 32%, and 42.5% of that of the control after treatment with phlorizin, santonin and amygdalin at 2 mg/ml, respectively. In the hemolymph and fat body, the amount of trehalose decreased in all cases. However, the effects of santonin on the alteration of the glycogen and glucose levels as well as the activities of glycogen phosphorylase, were different than those of the other two β‐glucosides. It appears that the three β‐glucosides have different influences on the carbohydrate metabolism of cotton bollworm.