A maize ADP‐ribosylation factor ZmArf2 increases organ and seed size by promoting cell expansion in Arabidopsis

ADP‐ribosylation factors (ARFs) are small GTP‐binding proteins that regulate a wide variety of cell functions. Previously, we isolated a new ARF, ZmArf2, from maize (Zea mays). Sequence and expression characteristics indicated that ZmArf2 might play a critical role in the early stages of endosperm development. In this study, we investigated ZmArf2 function by analysis of its GTP‐binding activity and subcellular localization. We also over‐expressed ZmArf2 in Arabidopsis and measured organ and cell size and counted cell numbers. The expression levels of five organ size‐associated genes were also determined in 35S::ZmArf2 transgenic and wild‐type plants. Results showed that the recombinant ZmArf2 protein purified from Escherichia coli exhibited GTP‐binding activity. Subcellular localization revealed that ZmArf2 was localized in the cytoplasm and plasma membrane. ZmArf2 over‐expression in Arabidopsis showed that 35S::ZmArf2 transgenic plants were taller and had larger leaves and seeds compared to wild‐type plants, which resulted from cell expansions, not an increase in cell numbers. In addition, three cell expansion‐related genes, AtEXP3, AtEXP5 and AtEXP10, were upregulated in 35S::ZmArf2 transgenic lines, while the expression levels of AtGIF1 and AtGRF5, were unchanged. Collectively, our studies suggest that ZmArf2 has an active GTP‐binding function, and plays a crucial role in growth and development in Arabidopsis through cell expansion mediated by cell expansion genes.     

Length‐weight relationships of five fish species from the Yalong and Wujiang rivers (tributaries of Yangtze River,China)

Length‐weight relationships (LWRs) were determined for five endemic fish species from the Yalong and Wujiang rivers (tributaries of the Yangtze River, China): Folifer brevifilis (Peters, 1881), Pelteobagrus ussuriensis (Dybowski, 1872), Schistura fasciolata (Nichols & Pope, 1927), Triplophysa daqiaoensis (Ding, 1993) and Triplophysa orientalis (Herzenstein, 1888). Samples were obtained between April 2004 and July 2014 using various fishing gear (set nets, drift gill nets, fish cages, hook and electro fishing). For each specimen from each species the sample size was recorded, total length and weight were measured and the LWR determined. Further, the 95% confidence intervals of a and b, and coefficient of correlation were estimated. Prior to this study, the LWRs for these five species were unknown.     

High‐throughput multiplex cpDNA resequencing clarifies the genetic diversity and genetic relationships among Brassica napus,Brassica rapa and Brassica oleracea

Brassica napus (rapeseed) is a recent allotetraploid plant and the second most important oilseed crop worldwide. The origin of B. napus and the genetic relationships with its diploid ancestor species remain largely unresolved. Here, chloroplast DNA (cpDNA) from 488 B. napus accessions of global origin, 139 B. rapa accessions and 49 B. oleracea accessions were populationally resequenced using Illumina Solexa sequencing technologies. The intraspecific cpDNA variants and their allelic frequencies were called genomewide and further validated via EcoTILLING analyses of the rpo region. The cpDNA of the current global B. napus population comprises more than 400 variants (SNPs and short InDels) and maintains one predominant haplotype (Bncp1). Whole‐genome resequencing of the cpDNA of Bncp1 haplotype eliminated its direct inheritance from any accession of the B. rapa or B. oleracea species. The distribution of the polymorphism information content (PIC) values for each variant demonstrated that B. napus has much lower cpDNA diversity than B. rapa; however, a vast majority of the wild and cultivated B. oleracea specimens appeared to share one same distinct cpDNA haplotype, in contrast to its wild C‐genome relatives. This finding suggests that the cpDNA of the three Brassica species is well differentiated. The predominant B. napus cpDNA haplotype may have originated from uninvestigated relatives or from interactions between cpDNA mutations and natural/artificial selection during speciation and evolution. These exhaustive data on variation in cpDNA would provide fundamental data for research on cpDNA and chloroplasts.     

Expression,purification, and breast cancer cell inhibiting effect of recombinant human lactoferrin C-lobe

Lactoferrin (LTF), a multifunctional glycoprotein of the transferrin family mainly found in exotic secretions in mammals, is an important defense molecule against not only microbial invasion but also tumors. It folds into two globular domains (N- and C-lobes) each containing an iron-binding site. The cationic antimicrobial peptide in N-lobe is known to exert anti-tumor effect via a non-receptor-mediated pathway. However, whether LTF C-lobe also contributes to its anti-tumor activity remains to be investigated. In this study, a human LTF fragment (amino acid residues 343–682) covering the C-lobe was expressed with a histidine tag in E. coli and the purified polypeptide refolded through a series of buffer changing procedure. The resultant recombinant protein caused significant growth arrest of breast carcinoma cells MDA-MB-231 in a dose- and time-dependent manner, evidently via induction of apoptosis of the cell. Our data suggest a positive role for the C-lobe of human LTF in controlling tumors in vitro.     

老年冠心病患者血清Lp-PLA2、hs-CRP、IL-27及MMP-9水平与Gensini积分的相关性研究*

目的:探讨老年冠心病患者血清脂蛋白相关磷脂酶A2(Lp-PLA2)、高敏C反应蛋白(hs-CRP)、白细胞介素-27(IL-27)及基质金属蛋白酶-9(MMP-9)水平与Gensini积分的相关性。方法:选取2015年10月至2018年2月我院收治的冠心病患者142例为研究对象,将所有患者按照不同的冠心病类型分为不稳定型心绞痛(UAP)组54例、稳定型心绞痛(SAP)组40例和急性心肌梗死(AMI)组48例。同时根据患者Gensini积分将其分为轻度47例、中度51例和重度44例。比较不同冠心病类型、不同严重程度的Lp-PLA2、hs-CRP、IL-27、MMP-9水平及Gensini积分,并分析冠心病患者上述指标水平与Gensini积分的相关性。结果:AMI组患者Lp-PLA2、hs-CRP、IL-27、MMP-9水平及Gensini积分均高于UAP组和SAP组,且UAP组高于SAP组(P0.05)。重度患者Lp-PLA2、hs-CRP、IL-27、MMP-9水平及Gensini积分均高于中度和轻度患者,且中度患者高于轻度患者(P0.05)。经Spearman相关性分析结果显示,冠心病患者Lp-PLA2、hs-CRP、IL-27、MMP-9水平与Gensini积分均呈正相关(P0.05)。结论:老年冠心病患者Lp-PLA2、hs-CRP、IL-27及MMP-9水平与患者冠状动脉病变Gensini积分均呈正相关。临床根据Lp-PLA2、hs-CRP、IL-27及MMP-9水平的变化,有助于评估老年冠心病患者的病情严重程度。     

Macular retinal thickness and flow density change by optical coherence tomography angiography after posterior scleral reinforcement

Optical coherence tomography angiography(Angio-OCT) has introduced a new non-invasive, quantitative method to assess superficial and deep capillary networks of the retina. In this study, we investigated macular retinal thickness and flow density change following posterior scleral reinforcement(PSR) surgery, using an RTVue XR Avanti Angio-OCT, in patients with pathological myopia. A total of 13 patients with pathological myopia were recruited and all patients completed the 6 months follow-up visit. Data from 22 eyes were used in this study. The mean age was 36.23±15.29 years, and 43%(n=6) were men.Spherical equivalent refractive error(SE) ranged from –8.0 to –24.0 D. Postoperative axial length, best-corrected visual acuity and SE did not change significantly at each follow-up, compared with pre-operative measures(P0.05). Postoperative flow density of superficial and deep retinal layers at each sector did not change significantly at each follow-up, compared with preoperative measures(P0.05). However, we found significant decrease in retinal thickness of parafovea-inferior sector after PSR surgery(P0.01), indicating potential relaxation of vitreofoveal traction after PSR surgery.