Development and application of a molecular marker for TMV resistance based on <Emphasis Type="Italic">N</Emphasis> gene in tobacco (<Emphasis Type="Italic">Nicotiana tabacum</Emphasis>)

Tobacco mosaic virus (TMV) caused serious loss in yield and quality of tobacco every year. It is a long-term goal to improve the tobacco resistance against TMV by tobacco breeding. N gene was the firstly reported TMV-resistant gene, which showed resistance against all Tobamoviruses except the Ob stain and belonged to the toll-interleukin-1 receptor/nucleotide-binding site/leucine-rich repeat class of plant resistance (R) genes. At present, N gene had already been widely used in tobacco conventional breeding, but there is rare available molecular maker used in marker-assisted selection of TMV resistance. In this study, we designed a pair of primers that specific amplify N gene fragment based on the sequence of N gene intron III, named N-marker. Then, we identified TMV resistance by two selecting methods, PCR with N-marker and inoculated with the TMV-C strain. Results from the two method showed that (1) 13 varieties among 67 tobacco varieties displayed hypersensitive reaction when inoculated with the TMV-C strain, also contained N gene fragments screened by PCR with N-marker; (2) 105 strains of 200 BC1 strains showed resistance against TMV when inoculated with TMV-C strain, meanwhile, 103 of the 105 strains contained N gene fragment verified by PCR with N-marker. Therefore, the N-marker is reliable for high throughput screening of germplasm resources and tobacco breeding materials in selection of N-mediated TMV resistance. Our study not only developed a molecular marker for tobacco breeding, but also identified new germplasm resources that are resistant to TMV.     

Determining resistance to <Emphasis Type="Italic">Fusarium verticillioides</Emphasis> and fumonisin accumulation in African maize inbred lines resistant to <Emphasis Type="Italic">Aspergillus flavus</Emphasis> and aflatoxins

Fusarium verticillioides and Aspergillus flavus cause Fusarium ear rot (FER) and Aspergillus ear rot (AER) of maize, respectively. Both pathogens are of concern to producers as they reduce grain yield and affect quality. F. verticillioides and A. flavus also contaminate maize grain with the mycotoxins fumonisins and aflatoxins, respectively, which has been associated with mycotoxicosis in humans and animals. The occurrence of common resistance mechanisms to FER and AER has been reported. Hence, ten Kenyan inbred lines resistant to AER and aflatoxin accumulation were evaluated for resistance to FER, F. verticillioides colonisation and fumonisin accumulation; and compared to nine South African lines resistant to FER and fumonisin accumulation. Field trials were conducted at three localities in South Africa and two localities in Kenya. FER severity was determined by visual assessment, while F. verticillioides colonisation and fumonisin content were quantified by real-time PCR and liquid chromatography tandem mass spectrometry, respectively. Significant genotype x environment interactions was determined at each location (P ≤ 0.05). Kenyan inbred CML495 was most resistant to FER and F. verticillioides colonisation, and accumulated the lowest concentration of fumonisins across localities. It was, however, not significantly more resistant than Kenyan lines CML264 and CKL05015, and the South African line RO549 W, which also exhibited low FER severity (≤5%), fungal target DNA (≤0.025 ng μL^?1) and fumonisin levels (≤2.5 mg kg^?1). Inbred lines resistant to AER and aflatoxin accumulation appear to be promising sources of resistance to F. verticillioides and fumonisin contamination.     

Advances on studies of miR-21 in vascular endothelial function and angiogenesis

MicroRNAs (miRNAs)are a class of non-coding, endogenous, single-stranded small RNA molecules composed of 19~25 nucleotides. miRNAs are widely involved in the process of human life activities. Recent studies have shown that part of miRNAs regulate the vascular endothelial function and angiogenesis. High expression of miRNA-21 is found to play important roles in the cell proliferation, cell apoptosis, cell growth and death of vascular endothelial cells. This review will focus on the recent progress related to miRNAs in vascular endothelial function and angiogenesis, providing a new insight in cardiovascular disease prevention, clinical diagnosis, prognosis and target therapeutics.     

绿皮苦瓜新品种冠春5号的选育

冠春5号是以高代自交系327作母本,以自交系186作父本配制而成的苦瓜一代杂种。植株生长势旺盛,早熟,从播种至始收82 d(天)。主侧蔓均可结果,主蔓第1雌花节位为第7~8节。瓜长棒形,瓜长25~35 cm,横径5~7 cm,肉厚0.9~1.0 cm,单瓜质量420 g左右。果表皮浅绿色,点状突起与短条状突起相间瘤状物,尾部钝,果肉脆,苦味淡。早春栽培一般每667 m~2产量约3 000 kg,田间对白粉病和疫病的抗性优于对照新农村油绿苦瓜。适宜四川、重庆等地种植。     

Inhibitory effect of AuNPs-Endostar on melanoma lung metastasis in mice

AIM: To observe the influence of gold nanoparticles combined with Endostar (AuNPs-Endostar) on the melanoma lung metastasis of mice and the underlying mechanism. METHODS: C57BL/6 mice (n=24) were selected for constructing the model of spontaneous lung metastasis of melanoma B16-F10 cells. Subsequently, the mice were randomly divided into Endostar group, AuNPs group, AuNPs-Endostar group and model group. After the formation of melanoma, the mice in each group were injected with different drugs through tail vein for 0.1 mL daily. After 9 d, the mice were narcotized for cutting the tumors in situ. After the operation, they were raised for 2 weeks before killed for obtaining the lung tissues to observe the situation of the metastasis. HE staining was utilized for observing the necrosis status of the tumors in situ, while immunostaining was applied for testing the expression of CD31, carbonic anhydrase-IX (CA-IX), vimentin and zonula occludens-1 (ZO-1) in the tumors. RESULTS: Compared with model group, the pulmonary metastasis in the groups with medical treatment was obviously reduced. In AuNPs-Endostar group, the metastasis inhibition rate was the highest, and the tumor necrosis was also decreased obviously, with the significant reduction of CD31, CA-IX and vimentin expression in the tumors and significant increase in ZO-1 expression. CONCLUSION: Compared with using Endostar or AuNPs alone, the combination of AuNPs with Endostar significantly improves the curative effect of inhibiting the pulmonary metastasis of melanoma in the mice. The mechanism may be related to reducing the tumor angiogenesis, norma-lizing the blood vessels and improving tumor hypoxia, thus inhibiting the tumor epithelial-mesenchymal transition, increasing the tight junctions between tumor cells and decreasing the invasiveness.     

Inhibitory effect of poncirin on viability of gastric cancer cells and underlying mechanism

AIM: To explore the effect of poncirin on the growth of AGS gastric cancer cells and the underlying mechanism.METHODS: The effect of poncirin on AGS cell viability was measure by MTT assay. The cell cycle distribution and cell apoptosis were analyzed by flow cytometry. Nuclear staining with DAPI was used to reflect the morphological change of the AGS cells treated with poncirin. The protein levels of extrinsic apoptosis pathway-related proteins such as FasL, caspase-8, caspase-3 and PARP, and mitochondria-mediated intrinsic apoptosis pathway-associated proteins such as Bak, Bcl-xL, Bax and caspase-9 were determined by Western blot.RESULTS: Poncirin inhibited the viability of AGS gastric cancer cells in a time-and concentration-dependent manner (P<0.05). Poncirin induced accumulation of G₁ DNA content and significantly increased total apoptosis in the AGS cells. Nuclear staining showed a dose-dependent increase in the number of apoptotic cells after treated with poncirin.The protein level of FasL was upregulated in a dose-dependent manner by treatment with poncirin. Poncirin significantly activated caspase-8 and caspase-3. Moreover, poncirin significantly induced the cleavage of PARP in a dose-dependent manner (P<0.05). In addition, the protein levels of Bcl-xL, Bax and Bak were unchanged after treated with different doses of poncirin. Furthermore, caspase-9 was not activated by poncirin treatment in the AGS cells.CONCLUSION: Poncirin has the anti-cancer effect via extrinsic apoptosis pathway to inhibit the growth of AGS gastric cancer cells, possibly making it a therapeutic agent for human gastric cancer treatment.     

溪荪新品种‘芭蕾女’

 ‘芭蕾女’是从溪荪（Iris sanguinea）田间自然杂交实生后代中选育出的新品种。2年生植株盛花期株高60 cm 左右,冠幅近52 cm,每株丛花葶数18 ~ 25,单葶花2 ~ 3朵。花形独特优美,盛开时外花被平展,内花被垂直向上,花色为蓝紫色,花径约9 cm,连续花期 20 d 左右。可在哈尔滨地区露地越冬,适宜推广应用到北方地区栽培。     

添加矿粉对农业废弃物育苗基质化学性质的影响

秸秆和畜禽粪便等农业废弃物代替草炭生产的育苗基质因存在小分子有机酸、铵态氮含量高等问题而影响到种子发芽和幼苗的生长。为改善这类育苗基质对种子发芽和幼苗生长的不良影响,以杨凌某公司生产的基质(该基质以菌糠、锯末、畜禽粪便等为主要原料)为材料,通过添加一种矿粉进行培养和育苗试验,研究矿粉添加比例对基质化学性质和小白菜(Brassica chinensis L.)发芽和生理指标的影响。结果表明:添加矿粉使基质的pH提高、NH_4~+-N/NO_3~--N比值和丁酸含量减小;与对照(不添加矿粉)相比,在矿粉添加比例为7%的条件下,小白菜发芽率、发芽势、发芽指数分别提高了35%、22.87%、34.6%;根际活力、叶绿素含量分别提高70.2%、32.1%,达到差异显著水平。     

NaCl胁迫对软枣猕猴桃幼苗生长发育的影响

以软枣猕猴桃幼苗为试材,研究了不同浓度NaCl胁迫处理对其幼苗生长发育及各项酶活性指标的影响。结果表明:软枣猕猴桃幼苗的株高、根长、株质量、根质量、胚轴长、胚轴质量均随NaCl胁迫浓度的升高而下降;过氧化物酶(POD)含量、超氧化物歧化酶(SOD)活性,均随NaCl胁迫浓度的增大而增大,而过氧化氢酶(CAT)活性、丙二醛(MDA)含量则随着NaCl胁迫浓度的增大而降低。