Innate immune memory in plants

The plant innate immune system comprises local and systemic immune responses. Systemic plant immunity develops after foliar infection by microbial pathogens, upon root colonization by certain microbes, or in response to physical injury. The systemic plant immune response to localized foliar infection is associated with elevated levels of pattern-recognition receptors, accumulation of dormant signaling enzymes, and alterations in chromatin state. Together, these systemic responses provide a memory to the initial infection by priming the remote leaves for enhanced defense and immunity to reinfection. The plant innate immune system thus builds immunological memory by utilizing mechanisms and components that are similar to those employed in the trained innate immune response of jawed vertebrates. Therefore, there seems to be conservation, or convergence, in the evolution of innate immune memory in plants and vertebrates.     

植物抗体及其应用

20世纪80年代末科学家将抗体基因转入烟草表达,标志着植物抗体的诞生.人类既可以以植物为生物反应器异源表达和生产具有药用及商业价值的蛋白质;也可用抗体在植物体中进行免疫调节,以研究植物生理代谢机制,或增加植物抵抗病虫害的能力.本文旨对植物抗体的优越性、表达生产及其在医药学、植物抗病及代谢等领域的进展进行综述和讨论.     

Development-dependent inheritance of 5-azacytidine-induced epimutations in triticale: analysis of rDNA expression patterns

Genomic imprinting of rye origin rDNA sequences in triticale is modulated by DNA methylation responsible for ontogenic expression patterns of those sequences. Considering the dynamic nature of these phenomena, we evaluated the influence of plant development on the inheritance of modified rye rDNA expression patterns. DNA hypomethylation was induced in triticale by 5-azacytidine (5AC) treatments at distinct developmental stages of M₁ plants, and expression patterns were analysed in M₂. The activity of rye origin rRNA genes in progeny of untreated and 5AC-treated plants was evaluated by silver staining in meristematic root tip cells and in meiocytes at diplotene. In the progeny of 5AC-treated plants, a significant increase in rye rDNA expression was observed, contrasting with the residual activity in untreated plants. Significant differential effects of 5AC treatments were observed in M₂ plants and correlated with the M₁ plant developmental stage in which DNA hypomethylation was induced. Hypotheses to explain the origin of those differences are discussed here.This revised version was published online in November 2005 with corrections to the Cover Date.     

Cross-reactivity between obeche wood (Triplochiton scleroxylon) and natural rubber latex

BACKGROUND: Several studies have shown that allergy to natural rubber latex is associated with cross reactivity to other plants. We have investigated a possible cross reactivity with a tree belonging to the Sterculiaceae family, Tryplochiton scleroxylon, in a patient allergic to obeche wood, that began to suffer symptoms of allergy in contact with latex. METHODS: Determinations of specific IgE by CAP to obeche, natural rubber latex (NRL) and recombinant allergens of latex were done. Immunoblotting was performed to study allergens detected by serum of our patient. CAP-inhibition methods were used to study cross-reactive between NRL and obeche wood. RESULTS: In obeche extract, 4 bands were found of an apparent molecular weight of 18, 38, 75 and 199 kDa. In NRL extract the allergens have a molecular weight around 18, 21, 32, 38, 60, 70 and 199 kDa. IgE to latex was almost completely inhibited (96%) by the obeche extract in CAP-inhibition studies. Using obeche extract as inhibitor, IgE binding to native hevein (nHevb 6.02) was reduced by 25%. CONCLUSIONS: The results obtained in CAP-inhibition demonstrate the existence of cross-reactivity between proteins in NRL and obeche wood. In our patient, a band of apparent molecular weight of 38 kDa could be the most important allergen.     

几种具有抗疲劳、抗缺氧作用的藏药植物资源

由于藏民族主要生活在高海拔地区,因此在藏药中有许多著名的抗疲劳、抗缺氧药用植物资源,如红景天、沙棘等。本文整理了沙棘、冬虫夏草、蕨麻和红景天等几种(类)具有抗疲劳、抗缺氧作用藏药植物资源及其目前有关这些植物资源的开发利用研究状况,以期为开发运动员专用保健饮料和保健食品提供参考。     

Targeting impaired nutrient sensing with repurposed therapeutics to prevent or treat age-related cognitive decline and dementia: A systematic review

BackgroundDementia is a debilitating syndrome that significantly impacts individuals over the age of 65 years. There are currently no disease-modifying treatments for dementia. Impairment of nutrient sensing pathways has been implicated in the pathogenesis of dementia, and may offer a novel treatment approach for dementia.AimsThis systematic review collates all available evidence for Food and Drug Administration (FDA)-approved therapeutics that modify nutrient sensing in the context of preventing cognitive decline or improving cognition in ageing, mild cognitive impairment (MCI), and dementia populations.MethodsPubMed, Embase and Web of Science databases were searched using key search terms focusing on available therapeutics such as ‘metformin’, ‘GLP1’, ‘insulin’ and the dementias including ‘Alzheimer’s disease’ and ‘Parkinson’s disease’. Articles were screened using Covidence systematic review software (Veritas Health Innovation, Melbourne, Australia). The risk of bias was assessed using the Cochrane Risk of Bias tool v 2.0 for human studies and SYRCLE’s risk of bias tool for animal studies.ResultsOut of 2619 articles, 114 were included describing 31 different ‘modulation of nutrient sensing pathway’ therapeutics, 13 of which specifically were utilized in human interventional trials for normal ageing or dementia. Growth hormone secretagogues improved cognitive outcomes in human mild cognitive impairment, and potentially normal ageing populations. In animals, all investigated therapeutic classes exhibited some cognitive benefits in dementia models. While the risk of bias was relatively low in human studies, this risk in animal studies was largely unclear.ConclusionsModulation of nutrient sensing pathway therapeutics, particularly growth hormone secretagogues, have the potential to improve cognitive outcomes. Overall, there is a clear lack of translation from animal models to human populations.     

Effect of plant phenolic compounds on biofilm formation by Pseudomonas aeruginosa

In the natural environment, bacteria predominantly exist in matrix‐enclosed multicellular communities associated with various surfaces, referred to as biofilms. Bacteria in biofilms are extremely resistant to antibacterial agents thus causing serious problems for antimicrobial therapy. In this study, we showed that different plant phenolic compounds, at concentrations that did not or weakly suppressed bacterial growth, increased the capacity of Pseudomonas aeruginosa PAO1 to form biofilms. Biofilm formation of P. aeruginosa PAO1 was enhanced 3‐ to 7‐fold under the action of vanillin and epicatechin, and 2‐ to 2.5‐fold in the presence of 4‐hydroxybenzoic, gallic, cinnamic, sinapic, ferulic, and chlorogenic acids. At higher concentrations, these compounds displayed an inhibiting effect. Similar experiments carried out for comparison with Agrobacterium tumefaciens C58 showed the same pattern. Vanillin, 4‐hydroxybenzoic, and gallic acids at concentrations within the range of 40 to 400 μg/mL increased the production of N–3‐oxo‐dodecanoyl‐homoserine lactone in P. aeruginosa PAO1 which suggests a possible relationship between stimulation of biofilm formation and Las Quorum Sensing system of this bacterium. Using biosensors to detect N‐acyl‐homoserine lactones (AHL), we demonstrated that the plant phenolics studied did not mimic AHLs.     

Allium sativum‐derived allitridin inhibits treg amplification in cytomegalovirus infection

This study investigated the effects of allitridin compound on murine cytomegalovirus (MCMV)‐induced regulatory T cell (Treg; CD4⁺CD25⁺Foxp3⁺) amplification in vivo and in vitro. One hundred twenty MCMV‐infected mice were allocated at random into two groups for treatment with allitridin or placebo. Another 120 mock‐infected mice were randomly allocated as controls for the allitridin treatment and placebo treatment groups. The mice were euthanized at various time points after infection (out to 120 days) to evaluate the effects of treatment on Treg presence and function, as well as MCMV infective load. Co‐culture with mouse embryo fibroblasts (MEF) and MCMV was performed to evaluate allitridin‐mediated Treg and anti‐CMV effects. The maximum tolerance concentration (MTC) of allitridin was used to treat cells for 3 days. Changes in Foxp3 mRNA and protein levels, percentages of T cell subsets, and Treg‐related cytokines (IL‐10 and TGF‐β) were measured. Allitridin treatment did not influence Foxp3 expression and Treg proportion in uninfected mice, but did down‐regulate each in infected mice during the chronic infection period. Additionally, allitridin treatment reduced the MCMV load in salivary glands. MTC allitridin treatment of co‐cultures partially blocked MCMV induction of Foxp3 mRNA and protein expression. In vitro treatment with allitridin also increased significantly the percentages of Tc1, Tc2, and Th1, reduced the secreted levels of IL‐10 and TGF‐β1, and significantly suppressed viral loads. In conclusion, allitridin can promote MCMV‐induced Treg expansion and Treg‐mediated anti‐MCMV immunosuppression. Therefore, allitridin may be useful as a therapeutic agent to enhance the specific cellular immune responses against CMV. J. Med. Virol. 85:493–500, 2013. © 2013 Wiley Periodicals, Inc.     

三枚中空螺纹加压钉+髂骨块植骨治疗股骨颈骨折的生物力学研究与临床应用

目的：对作者设计的三枚中空螺纹加压钉＋髂骨块植骨（ＨＳＩ）治疗股骨颈（头下型）骨折,进行生物力学分析。为临床应用提供科学依据。方法：利用新鲜尸股骨标本进行实验应力分析。比较三枚中空螺纹加压钉＋髂骨块植骨与单纯应用三枚中空螺纹加压钉固定（ＨＳ）比较,观察两者在内固定上的生物力学性能指标变化。结果;实验结果表明采用螺纹钉＋髂骨植骨固定（ＨＳＩ）与单纯采用螺纹钉固定（ＨＳ）治疗股骨颈（头下型）骨折,其生物力学性能无显著性差异。临床１３例实践证明。采用螺纹钉＋髂骨植骨术式符合生物力学模型。是治疗股骨颈（头下型）骨折一种有效的新方法。