Development of user-friendly markers for disease resistance to black root rot of tobacco through genotyping by sequencing

Black root rot (BRR), a disease caused by the hemibiotrophic fungus Thielaviopsis basicola, seriously compromises yield and leaf quality in tobacco (Nicotiana tabacum). Full resistance to black root rot, conferred by the resistance to BRR 1 (RBRR1) locus from Nicotiana debneyi Domin, was transferred to a burley tobacco cultivar through interspecific hybridization. Some undesirable traits potentially caused by linkage drag restrict wider application of RBRR1 in flue-cured tobacco. Therefore, user-friendly molecular markers are needed to assist selection for resistance to black root rot and to break the unfavorable linkage. Genotyping by sequencing (GBS) is a rapid and robust approach for reduced representation sequencing of multiplexed genomic DNA samples that combines genome-wide molecular marker discovery with genotyping. In the present study, we used GBS to identify single-nucleotide polymorphisms (SNPs) linked to the RBRR1 locus, and PCR-based assays for detection of these SNPs were also developed. Sequence analysis of the SNP markers suggested that RBRR1 is located on chromosome 17, providing a basis for map-based cloning of this valuable gene. Co-dominant CAPS markers that co-segregate with the disease-resistant phenotype offer user-friendly tools for tobacco breeding and variety improvement. Furthermore, tested with diverse N. tabacum germplasm, SS192650 displayed 100% selection accuracy for resistance to BRR, suggesting that this marker can be used in diverse tobacco populations.     

CD155 knockdown promotes apoptosis via AKT/Bcl‐2/Bax in colon cancer cells

CD155, one of the nectin‐like molecule family members, is involved in cell adhesion and motility. CD155 is overexpressed in several human cancers, but its role in proliferation and apoptosis of colorectal cancer remains unclear. We found that CD155 was up‐regulated in colorectal cancer tissues. CD155 knockdown via shRNA lentiviruses inhibited colon cancers cell migration and invasion, with a reduction in the expression of FAK, Src and MMP‐2. CD155 down‐regulation also suppressed colon cancer cell proliferation, accompanied by changing expressions of some molecules related to cell cycle. Finally, CD155 knockdown increased the expression ratio between Bax and Bcl‐2, resulting in a significant increase in colon cancer cell apoptosis. Taken together, these results demonstrate that CD155 is involved in not only migration and invasion but also proliferation and survival abilities of colon cancer cells, suggesting that CD155 is one of key molecules promoting the growth and metastasis of colorectal cancer.     

SPOCK1 promotes the invasion and metastasis of gastric cancer through Slug‐induced epithelial‐mesenchymal transition

Metastasis is a crucial impediment to the successful treatment for gastric cancer. SPOCK1 has been demonstrated to facilitate cancer metastasis in certain types of cancers; however, the role of SPOCK1 in the invasion and metastasis of gastric cancer remains elusive. SPOCK1 and epithelial‐mesenchymal transition (EMT)‐related biomarkers were detected by immunohistochemistry and Western blot in gastric cancer specimens. Other methods including stably transfected against SPOCK1 into gastric cancer cells, Western blot, migration and invasion assays in vitro and metastasis assay in vivo were also performed. The elevated expression of SPOCK1 correlates with EMT‐related markers in human gastric cancer tissue, clinical metastasis and a poor prognosis in patients with gastric cancer. In addition, knockdown of SPOCK1 expression significantly inhibits the invasion and metastasis of gastric cancer cells in vitro and in vivo, inversely, SPOCK1 overexpression results in the opposite effect. Interestingly, SPOCK1 expression has no effect on cell proliferation in vitro and in vivo. Regarding the mechanism(s) of SPOCK1‐induced cells invasion and metastasis, we prove that Slug‐induced EMT is involved in SPOCK1‐facilitating gastric cancer cells invasion and metastasis. The elevated SPOCK1 expression is closely correlated with cancer metastasis and patient survival, and SPOCK1 promotes the invasion and metastasis of gastric cancer through Slug‐mediated EMT, thereby possibly providing a novel therapeutic target for gastric cancer.     

Irisin inhibits high glucose‐induced endothelial‐to‐mesenchymal transition and exerts a dose‐dependent bidirectional effect on diabetic cardiomyopathy

Emerging evidence indicates that irisin provides beneficial effects in diabetes. However, whether irisin influences the development of diabetic cardiomyopathy (DCM) remains unclear. Therefore, we investigated the potential role and mechanism of action of irisin in diabetes‐induced myocardial dysfunction in mice. Type 1 diabetes was induced in mice by injecting streptozotocin, and the diabetic mice were administered recombinant r‐irisin (low or high dose: 0.5 or 1.5 μg/g body weight/day, I.P.) or PBS for 16 weeks. Irisin treatment did not alter blood glucose levels in the diabetic mice. However, the results of echocardiographical and histopathological assays indicated that low‐dose irisin treatment alleviated cardiac fibrosis and left ventricular function in the diabetic mice, whereas high‐dose irisin failed to mitigate the ventricular function impairment and increased collagen deposition. The potential mechanism underlying the effect of low‐dose irisin involved irisin‐mediated inhibition of high glucose‐induced endothelial‐to‐mesenchymal transition (EndMT); conversely, high‐dose irisin treatment enhanced high glucose‐induced MMP expression by stimulating MAPK (p38 and ERK) signalling and cardiac fibroblast proliferation and migration. Low ‐ dose irisin alleviated DCM development by inhibiting high glucose‐induced EndMT. By contrast, high‐dose irisin disrupted normal MMP expression and induced cardiac fibroblast proliferation and migration, which results in excess collagen deposition. Thus, irisin can inhibit high glucose‐induced EndMT and exert a dose‐dependent bidirectional effect on DCM.     

Knockdown of LINC01614 inhibits lung adenocarcinoma cell progression by up‐regulating miR‐217 and down‐regulating FOXP1

We tried to identify the function of LINC01614 in lung adenocarcinoma (LUAD) and reveal its underlying mechanisms. qRT‐PCR was applied to assess the expression of LINC016014 in LUAD tissues, noncancerous tissues and cells. Through colony formation assay, MTT assay and apoptosis analysis, we examined the variation of cell proliferation and apoptosis ability after silencing LINC01614. Moreover, the targeting interactions among LINC01614, miR‐217 and FOXP1 were validated via luciferase reporter assay, and then, we regulated the expression of miR‐217 and FOXP1 to ascertain their importance in cell proliferation and apoptosis. LINC01614 and FOXP1 were found to be up‐regulated in LUAD tumours and cells, whereas miR‐217 was down‐regulated. The experiment showed that target‐specific selectivity exists between LINC01614‐miR‐217 and miR‐217‐FOXP1 3′UTR. Furthermore, we disclosed that inhibition of LINC01614 could activate miR‐217, which subsequently restrained FOXP1. It was proved that LINC01614 promoted FOXP1 by inhibiting miR‐217, which ultimately stimulated the development of LUAD.     

Cooperative nest‐defence behaviour and territory quality in a resident and socially monogamous passerine

Nest defence is a fundamental aspect of parental care in secondary cavity‐nesting birds, and predation or competition for nesting sites can involve different defensive behaviours. Because habitat quality determines breeding success, we were interested in whether breeding pairs of the Eurasian nuthatch, Sitta europaea, established in more favourable environment also manifest higher probability of cooperative behaviour during their nest‐site defence. To explore this relationship, we quantified behavioural displays of both parents and analysed activity budget ethogram data from simulated territorial intrusions performed in the chick‐feeding phase with one conspecific and two different heterospecific stimuli (dummies of nuthatch, starling and woodpecker). We found that paired individuals shared their roles during nest‐site defence to a considerable extent. Males had a significantly higher number of attacks on intruders than females, and females performed more threat displays and controls of the brood than males. Multinomial analysis of the cooperative behaviour suggested that pairs in a high‐quality territory had higher probability of reciprocal substitution of different roles towards a balance between attacks, threat displays and nest controls. Contrary to this, pairs in a low‐quality territory had less likely pairwise combinations of simultaneous behavioural states that are associated with effective nest‐site defence. The difference in response probability according to territory quality was, however, highly variable in view of the stimulus that was used in simulated territorial intrusion. Because individual roles and the complex behavioural repertoire of pairs altered in response to territory quality and potential nest‐site competitor or brood predator, our results suggest that the cooperative nest‐defence behaviour could be linked to the breeding success of this year‐round territorial species living in a heterogeneous forest habitat.     

层迭灵芝子实体的体外抗肿瘤及免疫活性

【背景】层迭灵芝Ganoderma lobatum是灵芝属中的一个种,在民间有药用历史,但缺乏对其化学成分和药理活性的科学研究。【目的】以赤芝Ganoderma lingzhi子实体为参照,研究对比层迭灵芝子实体的抗肿瘤及免疫活性的强弱,探讨层迭灵芝的药用价值。【方法】采用化学分析及仪器分析的方法,比较2种灵芝子实体中三萜及多糖含量差异,并进行体外抗肿瘤及免疫活性研究。【结果】层迭灵芝和赤芝的子实体中三萜含量差异不大,分别为1.14%和1.21%,但2种灵芝中三萜化合物的种类差异较大。层迭灵芝子实体中的多糖含量较赤芝稍高,分别为3.60%和2.67%,2种子实体中多糖的重均分子量分布特征有所差别。2种灵芝醇提物对肿瘤细胞K562及SW620的增殖均具有一定的抑制活性,其中,层迭灵芝对SW620细胞具有较强的抑制活性,其IC50值达到了52.5μg/mL。2种灵芝水提物可以促进RAW 264.7细胞释放NO,说明两者均具有一定的免疫活性。【结论】层迭灵芝具有较好的抗肿瘤及免疫活性,可以作为药用开发的原料来源。     

Sequential decline in fruit resource allocation within inflorescences of Sagittaria trifolia: a test of non‐uniform pollination hypothesis

Flowering plants often exhibit declining resource investment to floral organs, fruits and seeds temporally or spatially in an inflorescence. To account for such variances, non‐uniform pollination hypothesis, which highlights various mating environments each flower experiences, provides adaptive significance for allocation patterns but with controversial supports. Sagittaria trifolia (Alismataceae) was used to examine differences in seed number, seed weight and germination rate among sequential fruits within inflorescences. Ovule number was also investigated to evaluate allocation patterns in the floral stage. To test the non‐uniform pollination hypothesis, we used three polymorphic microsatellite loci of S. trifolia to estimate the seed outcrossing rate in proximal and distal fruits. The results showed that the seed number, average seed weight and seed germination rate of S. trifolia gradually decreased from proximal to distal fruits within inflorescences. The percent of decrease in seed number between two contiguous fruits was 14.68 ± 3.22%, which was much stronger than the percent of decrease in ovule number at 6.95 ± 1.60%. Both proximal and distal fruits within inflorescences had high outcrossing rates (81.5 ± 5.0%, proximal; 82.3 ± 6.9%, distal) and they did not differ significantly. Overall, there was an acropetal decline of resource allocation to fruits within inflorescences of S. trifolia. Allocation pattern to ovules was not a limiting factor for seed production. The lack of difference in outcrossing rate between proximal and distal fruits indicated that the allocation strategy was probably not caused by non‐uniform pollination, but more likely position effects.