Hexanoic acid protects tomato plants against Botrytis cinerea by priming defence responses and reducing oxidative stress

Treatment with the resistance priming inducer hexanoic acid (Hx) protects tomato plants from Botrytis cinerea by activating defence responses. To investigate the molecular mechanisms underlying hexanoic acid‐induced resistance (Hx‐IR), we compared the expression profiles of three different conditions: Botrytis‐infected plants (Inf), Hx‐treated plants (Hx) and Hx‐treated + infected plants (Hx+Inf). The microarray analysis at 24 h post‐inoculation showed that Hx and Hx+Inf plants exhibited the differential expression and priming of many Botrytis‐induced genes. Interestingly, we found that the activation by Hx of other genes was not altered by the fungus at this time point. These genes may be considered to be specific targets of the Hx priming effect and may help to elucidate its mechanisms of action. It is noteworthy that, in Hx and Hx+Inf plants, there was up‐regulation of proteinase inhibitor genes, DNA‐binding factors, enzymes involved in plant hormone signalling and synthesis, and, remarkably, the genes involved in oxidative stress. Given the relevance of the oxidative burst occurring in plant–pathogen interactions, the effect of Hx on this process was studied in depth. We showed by specific staining that reactive oxygen species (ROS) accumulation in Hx+Inf plants was reduced and more restricted around infection sites. In addition, these plants showed higher ratios of reduced to oxidized glutathione and ascorbate, and normal levels of antioxidant activities. The results obtained indicate that Hx protects tomato plants from B. cinerea by regulating and priming Botrytis‐specific and non‐specific genes, preventing the harmful effects of oxidative stress produced by infection.     

Drug Effects on the Release of Endogenous Acetylcholine In Vivo: Measurement by Intracerebral Dialysis and Gas Chromatography–Mass Spectrometry

Intracerebral microdialysis was combined with a sensitive and specific gas chromatographic-mass spectrometric assay to measure the release of endogenous acetylcholine in the rat striatum in vivo. In rats anesthetized with urethane (1.2 g/kg i.p.), the levels of striatal acetylcholine dialyzed into a Ringer's perfusate were: (a) reliably measurable only in the presence of physostigmine; (b) stable at between 3 and 8 h of perfusion (30-75 pmol/20 min in the presence of 75 microM physostigmine); (c) reduced by calcium-free Ringer's solution, tetrodotoxin (0.1 microM), and vesamicol (1.0 microM); and (d) increased by elevated potassium (100 mM), atropine (3-300 microM), and haloperidol (0.75 mg/kg i.p.). In conscious unrestrained rats, the spontaneous release of striatal acetylcholine was not altered significantly following the administration of urethane. The changes in acetylcholine release observed in this study are consistent with the known actions of some drugs or ionic conditions on striatal cholinergic neurotransmission and are evident under the condition of urethane anesthesia. The present results demonstrate the sensitivity and suitability of this method for monitoring endogenous striatal acetylcholine release in vivo.     

Determination of Acidic Metabolites of Biogenic Amines in Human Aqueous Humour by Gas Chromatography-Negative Ion Chemical Ionisation Mass Spectrometry

The concentrations of acidic metabolites derived from the biogenic amines o-, m-, and p-tyramines (o-, m-, and p-hydroxyphenylacetic acids), p-octopamine/p-synephrine (p-hydroxymandelic acid), and dopamine (homovanillic acid and 3,4-dihydroxyphenylacetic acid) were measured in human aqueous humour obtained from patients undergoing elective surgery for cataract removal or for trabeculectomy as a treatment for chronic open-angle glaucoma. There were no clear differences in the pattern of metabolism of neurotransmitters between the two groups. An unexpected finding was that the o-tyramine metabolite, o-hydroxyphenylacetic acid, was present in aqueous humour.     

Auxins of non-flowering plants. I. Occurrence of 3-indoleacetic acid and phenylacetic acid in vegetative and fertile fronds of the ostrich fern (Matteucia struthiopteris)

Gas chromatography-mass spectrometry evidence is presented for the presence of both phenylacetic acid (PAA) and 3-indoleacetic acid (IAA) in vegetative and fertile tissues of the sporophyte of the ostrich fern [ Matteucia struthiopteris (L.) Todaro]. 3-Indolepropionic acid, tryptamine and 3-indoleacetonitrile were not found in tissue extracts, although small amounts of 3-indolebutyric acid and tryptophol may have been present. PAA was present in amounts higher than those found in flowering plants, while LAA levels fall within the angiosperm range. The levels of both auxins were higher in the younger vegetative tissues than in mature vegetative or fertile pinnae. Recent evidence for the occurrence of angiosperm growth hormones in ferns is discussed.     

Oxidative stress injury in tomato plants induced by supplemental UV-B radiation

Tomato (Lycopersicon esculentum Mill. cv. PKM 1) plants growing under field conditions were exposed for 15 d to solar radiation with UV-B component (280 - 320 nm) enhanced to 6.3 kJ m-2 d-1. This simulated a 15% stratospheric ozone depletion over Madurai (9° 50′ N latitude). Lipid peroxidation in the leaves of UV-B treated plants was 32% higher compared to the control. Superoxide dismutase (SOD) and catalase activities registered parallel promotion by 126 and 50 %, respectively, in the UV-B treated plants. Further, the contents of total phenols and anthocyanins in the leaves have also been enhanced by 40 and 156%, respectively. On the contrary, polyphenol oxidase activity demonstrated a 58 % inhibition in the leaves of UV-B treated plants. While anthocyanins and phenols are proposed to act as antioxidants, the reduction in polyphenol oxidase activity may maintain the turnover of phenols in the UV-B treated plants. This revised version was published online in July 2006 with corrections to the Cover Date.     

Identification and quantification of methyl jasmonate in leaf volatiles of Arabidopsis thaliana using solid-phase microextraction in combination with gas chromatography and mass spectrometry

Static headspace sampling with solid-phase microextraction has been used in combination with GC-FID and GC-MS for the specific enrichment, identification and quantification of volatile methyl jasmonate secreted by wounded leaves of Arabidopsis thaliana. The microsample method of analysis was found to be precise, accurate, sensitive and rapid. The detection limit of the procedure is 1.5 ppb (approximately 1.3 ng) per injection, which is of adequate sensitivity to detect the natural baseline levels of methyl jasmonate (approximately 10-100 ng/g) present in plant tissues. The method can be applied to most plants, requires a minimum of sample material, and shows the additional advantage that it is suitable for automation and could thus be used for high-throughput screening.     

Effects of co-existed proteins on measurement of pesticide residues in blood by gas chromatography-mass spectrometry

Accurate measurement of pesticides in biological fluids such as blood is important for quantifying environmental exposures. Beyond sample enrichment and separation, the method presented here is focused on studies of interactions between pesticides and co-existed proteins. It was experimentally demonstrated that entrapped or adsorbed pesticide residues within the folded native structures of proteins were poorly recovered using direct solvent extraction solely. We described here an effective approach termed Enzymatic Digestion-Organic Solvent Extraction (eDOSE) that utilizes the enzymatic approach to disrupt the folded structures of proteins and release entrapped or adsorbed pesticide residues. In this approach, samples were first reduced, alkylated, tryptically digested and then diluted 10 times before the subsequent extraction using an n-hexane solution. Resultant pesticide residues were determined by capillary gas chromatography coupled with a mass spectrometer. Mean recoveries of the 5 organophosphorus pesticides pre-spiked in fish blood including diazinon, parathion-methyl, malathion, parathion-ethyl and ethion were 85%, 95%, 84%, 103%, and 43% respectively using eDOSE strategy but only 24%, 45%, 40%, 27%, and 29% respectively using direct solvent extraction approach. The eDOSE approach was effective for demonstrating the critical role of folded native structure of serum albumin in adsorption of exogenous chemicals. It provides an alterative means for denaturation of proteins when the target analytes are not stable in acidic solution or entrapped within the protein aggregates caused by organic solvents such as acetone that have been applied for protein denaturation. The eDOSE approach should be able to combine with other advanced techniques of enrichment and separation for more efficient and accurate measurement of target compounds present in the context of complex biological systems. This approach can provide wide applications to the analysis of a variety of small molecules including environmental pesticide residues and metabolites as well as other toxins present in cells, tissues and biofluids.     

Induction of abiotic stress tolerance in plants by endophytic microbes

Endophytes are micro‐organisms including bacteria and fungi that survive within healthy plant tissues and promote plant growth under stress. This review focuses on the potential of endophytic microbes that induce abiotic stress tolerance in plants. How endophytes promote plant growth under stressful conditions, like drought and heat, high salinity and poor nutrient availability will be discussed. The molecular mechanisms for increasing stress tolerance in plants by endophytes include induction of plant stress genes as well as biomolecules like reactive oxygen species scavengers. This review may help in the development of biotechnological applications of endophytic microbes in plant growth promotion and crop improvement under abiotic stress conditions.

Significance and Impact of the Study

Increasing human populations demand more crop yield for food security while crop production is adversely affected by abiotic stresses like drought, salinity and high temperature. Development of stress tolerance in plants is a strategy to cope with the negative effects of adverse environmental conditions. Endophytes are well recognized for plant growth promotion and production of natural compounds. The property of endophytes to induce stress tolerance in plants can be applied to increase crop yields. With this review, we intend to promote application of endophytes in biotechnology and genetic engineering for the development of stress‐tolerant plants.     

Song learning as an indicator mechanism: modelling the developmental stress hypothesis

The ‘developmental stress hypothesis’ attempts to provide a functional explanation of the evolutionary maintenance of song learning in songbirds. It argues that song learning can be viewed as an indicator mechanism that allows females to use learned features of song as a window on a male's early development, a potentially stressful period that may have long-term phenotypic effects. In this paper we formally model this hypothesis for the first time, presenting a population genetic model that takes into account both the evolution of genetic learning preferences and cultural transmission of song. The models demonstrate that a preference for song types that reveal developmental stress can evolve in a population, and that cultural transmission of these song types can be stable, lending more support to the hypothesis.     

Health monitoring of plants by their emitted volatiles: trichome damage and cell membrane damage are detectable at greenhouse scale

Pathogen attack and herbivore infestation have a major impact on plant health. In a model study, these two plant health issues were simulated to study whether plant health can be monitored at greenhouse scale through the analysis of volatile organic compounds (VOCs) in greenhouse atmosphere. To simulate pathogen attack and herbivore infestation, we repeatedly stroked the stems of tomato plants ( Lycopersicon esculentum ) and repeatedly removed their side shoots. In addition, we studied the effect of fruit picking on the concentration of plant-emitted VOCs in greenhouse atmosphere. Analysis of air samples obtained before these treatments revealed up to 17 VOCs that are known to be released from tomato plants, of which the most dominant one was the monoterpene β-phellandrene. When plants were 7 weeks old, the concentration of this VOC was approximately 0.06 ppbv before treatment. When plants were 12 weeks old, this concentration was raised to approximately 0.14 ppbv. Stroking of the stems, removing the side shoots and fruit picking resulted in an increase in the concentrations of all mono- and most sesquiterpenes up to 60-fold, which was expected because these VOCs are well-known constituents of trichomes. The treatments did not result in substantially increased concentrations of the stress-related compounds α-copaene, methyl salicylate and ( E,E )-4,8,12-trimethyl-1,3,7,11-tridecatetraene. In contrast to stroking and fruit picking, shoot removal resulted in the emission of the lipoxygenase-derived product ( Z )-3-hexenol in greenhouse atmosphere expressing cell membrane degradation. The findings presented in this paper focus on the feasibility of monitoring plant health through the analysis of VOCs in greenhouse air, but findings might also be relevant for atmospheric chemistry.     

Bilateral asymmetry in skeletal growth and maturation as an indicator of environmental stress.

This study examined the efficacy of bilateral asymmetry in epiphyseal union as an indicator of environmental stress affecting the skeleton. We compared the extent of asymmetry in the postcranial skeleton between two cemetery samples excavated from Medieval Kulubnarti, Sudanese Nubia. Past studies have strongly suggested that these ancient Nubians experienced environmental stress-the early Christian period (550-750 AD) population to a greater extent than the late Christian period (750-1450 AD) population. We hypothesized that if bilateral asymmetry is a reflection of stress, then it should be present or greater in the more stressed population, the early Christian period population, while absent or found to a lesser extent in the less stressed population, the late Christian period population. We computed two mean values, representative of right-side and left-side epiphyseal union, for each individual in both cemetery samples, and tested for significant differences. Bilateral asymmetry was significant in the combined cemetery sample of 90 individuals (P < 0.019). When cemetery samples were tested separately, bilateral asymmetry was significant for the early Christian period sample (P < 0.001), but not for the late Christian period sample. There were no differences attributable to sex. Finally, we discuss why we conclude that environmental stress was favored over a biomechanic explanation as the cause for asymmetry. To the extent that our results support previous findings that early Christian period individuals were more affected by environmental stress than late Christian period individuals, it is reasonable to consider bilateral asymmetry in skeletal growth and maturation a good indicator of environmental stress.     

A fast and simple assay for busulfan in serum or plasma by liquid chromatography-tandem mass spectrometry using turbulent flow online extraction technology

Busulfan is used in myeloablative preparation regimens for hematopoietic bone marrow transplantation. Due to its narrow therapeutic range therapeutic drug monitoring of busulfan is recommended. In this study a fast and simple method for measuring busulfan in serum or plasma by liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been developed utilizing turbulent flow online extraction technology. Serum or plasma was mixed with acetonitrile containing d(8)-busulfan. After centrifugation the supernatant was injected onto a turbulent flow preparatory column then transferred to a C18 analytical column monitored by a tandem mass spectrometer set at positive electrospray ionization. The analytical cycle time was 4.0min. The method was linear from 0.15 to 41.90μmol/L with an accuracy of 87.9-103.0%. Inter- and intra-assay CVs across four concentration levels were 2.1-7.8%. No significant carryover or ion suppression was observed. No interference was observed from commercial control materials containing more than 100 compounds. Comparison with a well established LC-MS/MS method using patient specimens (n=45) showed a mean bias 1.3% with Deming regression of slope 1.02, intercept -0.02μmol/L, and a linear correlation coefficient 0.9883. The LC-MS/MS method coupled with turbulent flow online sample cleaning technology described here offers reliable busulfan quantitation in serum or plasma with minimum manual sample preparation and was fully validated for clinical use.     

气相色谱-质谱定量检测水产品腐败菌群体感应DKPs信号分子

【目的】为了分析水产品腐败菌群体感应的新型信号分子二酮哌嗪(DKPs)化合物,建立一种简便、灵敏的气相色谱-质谱(GC-MS)定量检测方法。【方法】通过优化气相色谱和质谱条件、培养基和提取溶剂建立定量检测方法,确定Cyclo-(L-Pro-L-Gly)、Cyclo-(L-Pro-L-Leu)、Cyclo-(L-Leu-L-Leu)和Cyclo-(L-Pro-L-Phe)4种DKPs标准品的特征离子,并检测水产品腐败菌荧光假单胞菌(Pseudomonas fluorescens)和波罗的海希瓦氏菌(Shewanella baltica)中的DKPs。【结果】4种DKPs化合物在1-200 mg/L范围内线性良好,检测限为0.06、0.10、0.06和0.04 mg/L,定量限为0.16、0.18、0.14和0.12 mg/L,回收率为51.8%-88.5%,标准偏差为1.4%-8.3%。以LB培养基为细菌培养基,氯仿作为萃取溶剂,检测的DKPs含量较高。两种水产品腐败菌都检测到DKPs活性,主要种类为Cyclo-(L-Pro-L-Leu)和Cyclo-(L-Pro-L-Phe)。随着两种细菌的生长,培养上清中DKPs含量显著增加,在12 h达到最高。【结论】建立了检测细菌DKPs的GC-MS定量方法,具有较高精密度、准确度,能够准确定量分析4种DKPs的含量。为探究水产品特定腐败菌DKPs的调控机制奠定基础。     

Progress and challenges for abiotic stress proteomics of crop plants

Plants are continually challenged to recognize and respond to adverse changes in their environment to avoid detrimental effects on growth and development. Understanding the mechanisms that crop plants employ to resist and tolerate abiotic stress is of considerable interest for designing agriculture breeding strategies to ensure sustainable productivity. The application of proteomics technologies to advance our knowledge in crop plant abiotic stress tolerance has increased dramatically in the past few years as evidenced by the large amount of publications in this area. This is attributed to advances in various technology platforms associated with MS‐based techniques as well as the accessibility of proteomics units to a wider plant research community. This review summarizes the work which has been reported for major crop plants and evaluates the findings in context of the approaches that are widely employed with the aim to encourage broadening the strategies used to increase coverage of the proteome     

植物根边缘细胞的抗逆性研究进展

综述了近几年来国内外有关植物根边缘细胞抗逆性方面的研究,重点概述植物根边缘细胞对生物与非生物胁迫的响应及其相应的抗性机理。在生物胁迫下,边缘细胞能吸引和固定病原根结线虫,排斥或约束致病性细菌,可作为真菌感染的假目标,减少或避免各种病原菌对根尖的伤害。在非生物胁迫下,边缘细胞通过分泌粘液、诱导ROS产生刺激细胞死亡以抵抗铝毒,并通过其数量的改变来调节高温、高浓度CO2等多种生理反应。最后在当前植物根边缘细胞研究的基础上,提出了今后的研究方向。     

Potassium-Induced Release of Endogenous Morphine from Rat Brain Slices

Abstract: Endogenous morphine has been clearly demonstrated by gas chromatography/mass spectrometry in the brain, spinal fluid, adrenal glands, and liver of mammals. To clarify the role of endogenous morphine, its release from rat brain slices was studied in vitro in the presence of high potassium concentrations, with and without calcium in the medium. The perfusate was hydrolyzed, solid phase-extracted, and then analyzed by gas chromatography/mass spectrometry. Depolarization due to high potassium concentrations increased the release of the alkaloid manyfold with respect to the basal value, and the release was dependent on the presence of calcium in the medium. These results suggest that endogenous morphine might act as a neurotransmitter or neuromodulator in the rat CNS.     

The Response of Haloferax volcanii to Salt and Temperature Stress: A Proteome Study by Label‐Free Mass Spectrometry

In‐depth proteome analysis of the haloarchaeal model organism Haloferax volcanii has been performed under standard, low/high salt, and low/high temperature conditions using label‐free mass spectrometry. Qualitative analysis of protein identification data from high‐pH/reversed‐phase fractionated samples indicates 61.1% proteome coverage (2509 proteins), which is close to the maximum recorded values in archaea. Identified proteins match to the predicted proteome in their physicochemical properties, with only a small bias against low‐molecular‐weight and membrane‐associated proteins. Cells grown under low and high salt stress as well as low and high temperature stress are quantitatively compared to standard cultures by sequential window acquisition of all theoretical mass spectra (SWATH‐MS). A total of 2244 proteins, or 54.7% of the predicted proteome, are quantified across all conditions at high reproducibility, which allowed for global analysis of protein expression changes under these stresses. Of these, 2034 are significantly regulated under at least one stress condition. KEGG pathway enrichment analysis shows that several major cellular pathways are part of H. volcanii’s universal stress response. In addition, specific pathways (purine, cobalamin, and tryptophan) are affected by temperature stress. The most strongly downregulated proteins under all stress conditions, zinc finger protein HVO_2753 and ribosomal protein S14, are found oppositely regulated to their immediate genetic neighbors from the same operon.