植物生物反应器研究进展

植物生物反应器是近年来生物技术领域新的研究方向,利用农作物进行疫苗、药用蛋白的生产,具有广阔的市场前景和商业价值。研究证明,用各种农作物为载体的植物生物反应器产品可通过种子、果实或块茎表达,便于贮藏、运输和利用。它拓宽了传统农业概念,成为现代生物农业重要的研究方向之一,推动了生物经济快速健康的前进,促进农业可持续发展。综述植物生物反应器的研究与应用现状,并对转基因作物作为植物生物反应器的发展前景作分析和展望。     

Effects of Clinoptilolite on Growth Performance and Antioxidant Status in Broilers

The objective of this study was to compare the effects of natural clinoptilolite and modified clinoptilolite on growth performance and antioxidant capacity in broiler chicks. Two hundred forty 1-day-old commercial Arbor Acres broilers were randomly distributed into three treatments, each of which had eight replicates. Each replicate contains 10 chicks. Control (CON) group fed with the basal diets, natural clinoptilolite (NCLI) group fed basal diets with 2 % natural clinoptilolite, and modified clinoptilolite (MCLI) group fed basal diets with 2 % modified clinoptilolite for 42 days. The results showed that the 2 % supplementation of natural clinoptilolite and modified clinoptilolite had no adverse effect on growth performance of broilers at 42 days of age. Relative weights of organs were not influenced by dietary treatments at 21 and 42 days. The activity of total nitric oxide synthase was significantly (P?<?0.05) decreased in MCLI group than CON group at 21 days of age. At 21 and 42 days, the activities of glutathione peroxidase, catalase, total superoxide dismutase, total antioxidant capacity (T-AOC) were significantly (P?<?0.05) increased in NCLI and MCLI groups than the CON group while there was no difference in T-AOC between CON and NCLI groups. The malondialdehyde content was significantly (P?<?0.05) decreased in NCLI and MCLI groups than the CON group. It was concluded that the addition of 2 % natural clinoptilolite and modified clinoptilolite to diet can improve antioxidant capacity in broilers, although their effects on growth performance was negligible.     

链霉菌IMS002的分类鉴定及其抗真菌活性物质解析

【目的】对一株分离自植物根际土壤的具有抗真菌活性的链霉菌IMS002进行菌株分类鉴定,通过活性追踪分离纯化并鉴定有机相中的活性物质。【方法】通过16S rDNA和5个不同基因(atpD,gyrB,recA,rpoB,trpB)串联聚类分析以及生理生化实验分析,对链霉菌IMS002进行菌株分类鉴定,用扫描电子显微镜观察该株链霉菌的菌丝及孢子形态,以尖孢镰刀菌(Fusarium oxysporum)为指示菌进行生物活性追踪,通过硅胶柱层析、凝胶柱层析及高压液相色谱(HPLC)对活性物质进行分离和纯化,使用液质联用高分辨质谱仪、500 MHz核磁共振波谱仪以及圆二色光谱仪确定该物质的化学结构。【结果】IMS002经初步鉴定与产二素链霉菌(Streptomycesambofaciens)具有较近的亲缘关系,其发酵液对尖孢镰刀菌具有良好的抑菌效果,经分离和纯化以及现代波谱技术分析,确定有机相中的抑菌活性组分为Borrelidin。【结论】链霉菌IMS002能够产生化合物Borrelidin,该化合物对尖孢镰刀菌具有抑制活性。     

Quantitative Assessment of Common Genetic Variants on Chromosome 5p12 and Hormone Receptor Status with Breast Cancer Risk

Several genome-wide association studies on breast cancer (BC) have reported similar findings of a new susceptibility locus, 5p12. After that, a number of studies reported that the rs10941679, rs4415084, and rs981782 polymorphism in chromosome 5p12 has been implicated in BC risk. However, the studies have yielded contradictory results. To derive a more precise estimation of the relationship, a meta-analysis of 131,983 BC cases and 200,314 controls from 24 published case–control studies was performed. Overall, significantly elevated BC risk was associated with rs10941679, rs4415084, and rs981782 risk allele when all studies were pooled into the meta-analysis. In the subgroup analysis by ethnicity, significantly increased risks were found for the rs10941679 and rs4415084 polymorphism among Caucasians and East Asians, while no significant associations were observed for the two polymorphisms in African and other ethnic populations. For 5p12-rs981782, significant associations were only detected among Caucasians. In addition, we found that rs10941679 and rs4415084 on 5p12 confer risk, exclusively for estrogen receptor (ER)-positive tumors with per-allele OR of 1.16 (95% CI: 1.11–1.21; P<10⁻⁵) and of 1.14 (95% CI: 1.09–1.19; P<10⁻⁵) respectively. Ethnicity was identified as a potential source of between-study heterogeneity. In conclusion, this meta-analysis demonstrated that common variations are a risk factor associated with increased BC susceptibility, but these associations vary in different ethnic populations.     

Isolation and Identification of a Novel Antifungal Protein from a Rhizobacterium Bacillus subtilis Strain F3

Bacillus subtilis strain F3, isolated from peach rhizosphere soil, is an antifungal bacterium against many plant pathogens. In this study, the antifungal protein was isolated and purified by ammonium sulphate and chromatography, then identified by mass spectrum analysis. By sequential chromatography of Sephadex G‐50, DEAE‐Sephadex A‐25 anion exchange and Sephadex G‐100, a fraction designated as F3A was isolated to show a single protein band in SDS‐PAGE and be antagonistic towards Monilinia fructicola. The peptide mass fingerprinting of the protein band of F3A had high similarity with the amino acid sequences of several flagellin protein of B. subtilis. There were seven amino acid fragments matched with the protein having the highest score, and sequence coverage was 33%. F3A showed a strongly inhibitory effect to the growth and sporulation of M. fructicola. There were little aerial hyphae and conidia at the antifungal zone, and the hyphae were abnormal with some cell wall collapse and several vacuoles in cells.     

Production of the endocannabinoids anandamide and 2-arachidonoylglycerol by endothelial progenitor cells

Recent studies have highlighted the importance of paracrine growth factors as mediators of pro-angiogenic effects by endothelial progenitor cells (EPCs), but little is known about the release of lipid-based factors like endocannabinoids by EPCs. In the current study, the release of the endocannabinoids anandamide and 2-arachidonoylglycerol by distinct human EPC sub-types was measured using HPLC/tandem mass-spectrometry. Anandamide release was highest by adult blood colony-forming EPCs at baseline and they also demonstrated increased 2-arachidonoylglycerol release with TNF-alpha stimulation. Treatment of mature endothelial cells with endocannabinoids significantly reduced the induction of the pro-inflammatory adhesion molecule CD106 (VCAM-1) by TNF-alpha.     

A primary study on relationships between subfossil chironomids and the distribution of aquatic macrophytes in three lowland floodplain lakes,China

Aquatic macrophytes act as an important substrate for zoobenthos-supporting midge communities (chironomids) that can be used for reconstructing past environmental change. This study selected three macrophyte-dominated lakes in the middle reach of the Yangtze floodplain (central China), to identify relationships between macrophyte characteristics (i.e. communities, richness and biomass) and subfossil chironomid assemblages. One-way ANOSIM tests illustrated that there were significant differences in chironomid community compositions between lakes. Most chironomid taxa were not selective of dominant macrophyte species, but Corynoneura species were found to be associated with the development of Vallisneria as revealed by SIMPER analysis. Multivariate analyses indicate that submerged plant biomass, water depth and secchi depth, conductivity and the concentration of HCO₃ ^? were significantly correlated with midge compositions. Overall, this study corroborates the existing opinions that chironomid species show little selectivity to plant type but are significantly influenced by plant density. As an exception to this general trend, we found strong associations between Corynoneura chironomid larvae and Vallisneria macrophytes, prompting the need for future experimental studies to confirm this association.     

Inhibition of Angiotensin II-Induced Cardiac Hypertrophy and Associated Ventricular Arrhythmias by a p21 Activated Kinase 1 Bioactive Peptide

Cardiac hypertrophy increases the risk of morbidity and mortality of cardiovascular disease and thus inhibiting such hypertrophy is beneficial. In the present study, we explored the effect of a bioactive peptide (PAP) on angiotensin II (Ang II)-induced hypertrophy and associated ventricular arrhythmias in in vitro and in vivo models. PAP enhances p21 activated kinase 1 (Pak1) activity by increasing the level of phosphorylated Pak1 in cultured neonatal rat ventricular myocytes (NRVMs). Such PAP-induced Pak1 activation is associated with a significant reduction of Ang II-induced hypertrophy in NRVMs and C57BL/6 mice, in vitro and in vivo, respectively. Furthermore, PAP antagonizes ventricular arrhythmias associated with Ang II-induced hypertrophy in mice. Its antiarrhythmic effect is likely to be involved in multiple mechanisms to affect both substrate and trigger of ventricular arrhythmogenesis. Thus our results suggest that Pak1 activation achieved by specific bioactive peptide represents a potential novel therapeutic strategy for cardiac hypertrophy and associated ventricular arrhythmias.     

Effects of yeast antagonist in combination with UV-C treatment on postharvest diseases of pear fruit

The yeast antagonist Candida guilliermondii and ultraviolet-C (UV-C) treatment were investigated for controlling infection following artificial inoculation with Penicillium expansum or Botrytis cinerea, or natural infection in pear fruit stored at 20°C. Applied separately, both C. guilliermondii and UV-C (5 kJ m⁻²) effectively inhibited decay caused by P. expansum or B. cinerea, and natural infection. The combination of C. guilliermondii and UV-C showed better control efficacy. Application of UV-C did not affect the growth of C. guilliermondii in pear fruit wounds, while UV-C induced a significant increase in the activities of chitinase, β-1,3-glucanase, catalase and peroxidase in pear fruit. The mechanism by which UV-C enhanced the biocontrol efficacy of C. guilliermondii may be related to the elicitation of defense responses in pear fruit. The combination of C. guilliermondii and UV-C radiation could be a promising method for the control of P. expansum and B. cinerea in pear fruit.