生长抑素受体2的小鼠时空组织表达谱

生长抑素(somatostatin, SST)作为一种抑制性多肽激素,在多种生物过程中发挥重要的功能。生长抑素受体2 (somatostatin receptor 2, SSTR2)作为生长抑素表达最广泛的受体在多种组织中表达,但其表达的具体细胞类型尚不清楚。本研究在小鼠不同发育阶段的多种组织中鉴定了SSTR2蛋白表达的细胞类型。通过多色免疫荧光在小鼠胚胎期15.5 d、出生后1 d、7 d、15 d、3个月和6个月的脑、骨、肺、肠道、皮肤、胃、脾和肾等组织中检测了Sstr2基因的表达。结果发现Sstr2在不同发育阶段的多种组织的特定细胞类型中表达,包括脑神经元和星形胶质细胞,骨的间充质基质细胞、造血细胞和B细胞,肺的巨噬细胞、Ⅱ型肺泡上皮细胞和气道纤毛细胞,肠道的上皮细胞和神经元,皮肤的毛囊细胞,胃体的上皮细胞,脾的造血干细胞、造血祖细胞和神经纤维,肾的肾小管上皮细胞等。本研究确定了小鼠多组织不同发育阶段Sstr2表达的细胞类型,为生长抑素与生长抑素受体2的生理功能研究提供了新的线索。     

A meta-analysis on morphological,physiological and biochemical responses of plants with PGPR inoculation under drought stress

Plant growth-promoting rhizobacteria (PGPR) can help plants to resist drought stress. However, the mechanisms of how PGPR inoculation affect plant status under drought remain incompletely understood. We performed a meta-analysis of plant response to PGPR inoculation by compiling data from 57 PGPR-inoculation studies, including 2, 387 paired observations on morphological, physiological and biochemical parameters under drought and well-watered conditions. We compare the PGPR effect on plants performances among different groups of controls and treatments. Our results reveal that PGPR enables plants to restore themselves from drought-stressed to near a well-watered state, and that C4 plants recover better from drought stress than C3 plants. Furthermore, PGPR is more effective underdrought than well-watered conditions in increasing plant biomass, enhancing photosynthesis and inhibiting oxidant damage, and the responses of C4 plants to the PGPR effect was stronger than that of C3 plants under drought conditions. Additionally, PGPR belonging to different taxa and PGPR with different functional traits have varying degrees of drought-resistance effects on plants. These results are important to improve our understanding of the PGPR beneficial effects on enhanced drought-resistance of plants.     

Comparative Transcriptome Analyses Reveal Genes Related to Spine Development in Cucumber (<i>Cucumis sativus</i>)

Fruit spine is an important quality trait of cucumber. To better understand the molecular basis of cucumber spine development and function, RNA-Seq was performed to identify differentially expressed genes (DEGs) in fruit spines of different development stages, namely, 8 days before anthesis (SpBA8), anthesis (SpA) and 8 days after anthesis (SpAA8). Stage-wise comparisons obtained 2,259 (SpBA8 vs. SpA), 4,551 (SpA vs. SpAA8), and 5,290 (SpBA8 vs. SpAA8) DEGs. All the DEGs were classified into eight expression clusters by trend analysis. Among these DEGs, in addition to the Mict, Tril, CsTTG1, CsMYB6, NS, and Tu genes that have been reported to regulate fruit spine formation, we found that the CsHDG11, CsSCL8, CsSPL8, CsZFP6 and CsZFP8 may also be involved in spine development in cucumber. Our study provides a theoretical basis for further research on molecular mechanisms of spine development in cucumber.     

By-Products of Zea mays L.: A Promising Source of Medicinal Properties with Phytochemistry and Pharmacological Activities: A Comprehensive Review

Zea mays (Z. mays) is one of the main cereal crops in the world, and it′s by-products have exhibited medicinal properties to explore. This article intends to review the chemical compositions and pharmacological activities of by-products of Z. mays (corn silks, roots, bract, stems, bran, and leaves) which support the therapeutic potential in the treatment of different diseases, with emphasis on the natural occurring compounds and detailed pharmacological developments. Based on this review, 231 natural compounds are presented. Among them, flavonoids, terpenes, phenylpropanoids, and alkaloids are the most frequently reported. The by-products of Z. mays possess diuretic effects, hepatoprotective, anti-diabetic, antioxidant, neuroprotective, anti-inflammatory, anti-cancer, plant protection activity, and other activities. This article reviewed the phytochemistry and pharmacological activities of Z. mays for comprehensive quality control and the safety and effectiveness to enhance future application.     

Comparative analysis of 343 plastid genomes of Solanum section Petota: Insights into potato diversity,phylogeny, and species discrimination

Common potato (Solanum tuberosum L.) and its wild relatives belong to Solanum section Petota. This section's phylogeny and species delimitation are complicated due to various ploidy levels, high heterozygosity, and frequent interspecific hybridization. Compared to the nuclear genome, the plastid genome is more conserved, has a haploid nature, and has a lower nucleotide substitution rate, providing informative alternative insights into the phylogenetic study of section Petota. Here, we analyzed 343 potato plastid genomes from 53 wild and four cultivated species. The diversity of sequences and genomes was comprehensively analyzed. A total of 24 species were placed in a phylogenetic tree based on genomic data for the first time. Overall, our results not only confirmed most existing clades and species boundaries inferred by nuclear evidence but also provided some distinctive species clade belonging and the maternally inherited evidence supporting the hybrid origin of some species. Furthermore, the divergence times between the major potato clades were estimated. In addition, the species discriminatory power of universal barcodes, nuclear ribosomal DNA, and whole and partial plastid genomes and their combinations were thoroughly evaluated; the plastid genome performed best but had limited discriminatory power for all survey species (40%). Overall, our study provided not only new insights into phylogeny and DNA barcoding of potato but also provided valuable genetic data resources for further systematical research of Petota.     

壳多糖酶研究的概况及最新进展

壳多糖酶专一性水解壳多糖中的β－1,4糖苷键,在自然界的碳循环中具有极其重要的意义．壳多糖酶分布广泛,功能多样,在真菌生长发育、植物抗真菌感染等生理过程中壳多糖酶均发挥重要作用．文章概述了壳多糖酶研究的现状及最新进展,介绍了壳多糖酶的分布、理化性质、催化性质、在细胞中的定位及其调控;简介了近年来真菌和植物壳多糖酶研究的动态及最新进展.     

心肌电兴奋传导速度对心律失常影响的仿真研究

心电场是由心肌的电活动产生的。心肌细胞的电特性及心肌细胞间的传导关系决定了体表电位的分布及心电图的变化。心肌电兴奋传导速度则是影响心肌间兴奋传导关系的重要参数之一。由于很难通过实验方法来人为改变电兴奋传导速度,因而临床上有关该参数对心律影响的定量知识相当缺乏。本文采用真实三雏躯干模型及心脏模型,对心肌电兴奋传导速度与心律变化的关系进行定量仿真研究。结果表明,兴奋传导速度决定了整个心电图的变化,而局部普通心肌的传导速度在相当范围内变化似乎对心电图影响不明显,但传导速度超过一定范围后可能产生突变。