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[学术文献 ] Role of terpenes in plant defense to biotic stress 进入全文
Biocontrol Agents and Secondary Metabolites 图书
Terpenes constitute a highly diverse class of chemical compounds produced by the plant and playing a role in many functions, both physiological and ecological. Plants constantly interact with other organisms, from beneficial to detrimental, and evolved sophisticated regulatory mechanisms to control these interactions. The role of terpenes, or more in general of terpenoids, as preformed or induced chemical deterrents to herbivores is known since long, and their complex role in plant defense against pathogens is increasingly present in the scientific literature. The synthesis of terpenes is one of the responses to attack in numerous plant-pathogen binomials, where terpenes act as specialized or generalized pathogen inhibitors. In this chapter, the involvement of terpenes and terpenoids in resistance to plant pathogens, such as fungi, bacteria, and viruses, and, where relevant, their vectors, is described.
[学术文献 ] Role of phenols and polyphenols in plant defense response to biotic and abiotic stresses 进入全文
Biocontrol Agents and Secondary Metabolites 图书
Crops represent an integral part of mankind. They produce a range of primary and secondary metabolites with different functions. A large and diverse group of secondary metabolites, represented by phenols and polyphenols, are synthesized by crops for physiological roles in its life cycle. The physiological roles include growth regulation, interactions with ethylene, lignin and pigment biosynthesis, etc. Among the various roles of the metabolites, they have also been known to be capable of scavenging harmful reactive oxygen species in various organisms. In plants, there has been an increased biosynthesis of phenol and polyphenol compounds to help them cope with the multifarious abiotic and biotic stresses such as salinity, heavy metal, drought, temperature, UV lights, disease progression, etc. This chapter focusses on the classification and of phenolic and polyphenolic compounds and its biosynthesis through various pathways in the crops. The specificity of the protection to crop stress conferred by each of these compounds and the role of the compounds in plant growth are also discussed in detail. Conclusively, the ability of the secondary metabolite will help us understand the different mechanisms adopted by the crops to survive and inhabit unfavorable environments.
[学术文献 ] Effects of baculovirus-killed cadavers on plant defenses and insect behavior 进入全文
Arthropod-Plant Interactions 期刊
Baculoviruses are a group of entomopathogenic viruses that are important natural enemies of insects, particularly lepidopteran larvae. An important component of baculovirus transmission efficiency is the frequency with which hosts encounter patchily distributed virions on plants. Little is known about the ecology and bacterial composition of virus-killed cadavers. We used a baculovirus and host Trichoplusia ni caterpillars to study the effects of virus-killed cadavers on tomato plant defenses and T. ni behavior. We also compared bacterial communities associated with virus-killed and uninfected (freeze-killed) cadavers and found that there was no significant difference in community composition and membership between tomato-fed virus-killed or freeze-killed cadavers. Comparison of virus-killed cadavers from two separate experiments revealed significant differences in bacterial community composition, suggesting that host plant could play a more important role in shaping bacterial communities than virus infection status. Culture-dependent plating indicated that virus-killed cadavers had significantly higher bacterial titers compared with uninfected cadavers. We found that virus-killed cadavers suppressed polyphenol oxidase activity, an important plant defense protein, in mechanically damaged plants, but not in plants damaged by herbivory. Although cadavers did not influence plant defenses induced by feeding damage inflicted by healthy or infected T. ni, this study provides the first evidence that baculoviruses could influence plant defenses through host cadavers. When applied to intact plants, neither virus-killed or freeze-killed cadavers influenced T. ni oviposition, larval choice, or larval consumption, indicating these insects did not discriminate cadaver cues. Virus-killed cadavers could play important roles in mediating interactions between plants, herbivores, and other trophic levels, with potential implications for viral transmission dynamics.
[学术文献 ] Sensitive Detection of Fungicide Folpet by Surface-Enhanced Raman Scattering: Experimental and Theoretical Approach 进入全文
Chemosensors 期刊
In this work, Surface-Enhanced Raman Spectroscopy (SERS) was employed as an effective detection technique for folpet, characterized by its notable specificity and sensitivity. The investigation involved the use of UV–Vis, Raman, and SERS spectroscopy of folpet at different concentrations for a comprehensive study of plasmon-driven effects such as plasmon resonance, plasmon hybridization, and electric field enhancement resulting in the SERS’ intensification. Specifically, SERS detection of folpet solutions at concentrations below 100 µM is presented in detail by using Ag nanoparticles prepared with hydroxylamine reduction. The experimentation encompassed diverse conditions to optimize the detection process, with Raman spectra acquired for both folpet powder and aqueous solution of folpet at the natural pH. SERS analyses were conducted across a concentration range of 9.5 × 10−8 to 1.61 × 10−4 M, employing 532 nm excitation. The differences in the spectral profiles observed for folpet Raman powder and SERS are ascribed to N–S cleavage; these changes are attributed to plasmon catalysis induced by the used Ag nanoparticles. Transmission electron microscopy (TEM) was also important in the present analysis to better understand which mechanism of nanoparticles aggregation is more favorable for the SERS detection regarding the formation of hot spots in the suspension. Complementing the experimental data, the molecular structure and theoretical Raman spectra of the folpet molecule were calculated through density functional theory (DFT) methods. The outcomes of these calculations were crucial in the elucidation of folpet’s vibrational modes. The culmination of this research resulted in the successful detection of folpet, achieving a notable limit of detection at 4.78 × 10−8 M. This comprehensive approach amalgamates experimental and theoretical methodologies, offering significant insights into the detection capabilities and molecular characteristics of folpet via SERS analysis.
[学术文献 ] Rapid and cost-effective detection of perchlorate in water using paper-based analytical devices 进入全文
Desalination and Water Treatment 期刊
This study aimed to develop and evaluate the performance of a microfluidic paper-based device for measuring perchlorate levels in water samples. Smartphone-based digital imaging was integrated with microfluidic paper-based analytical device to establish a reliable colorimetric method for detecting perchlorate contamination. The results demonstrated successful quantitative estimation of perchlorate levels in water samples using a colorimetric assay based on the methylene blue-perchlorate reaction. Real-time, on-site colorimetric data were collected using a digital smartphone, and image processing methods were used to detect the occurrence of perchlorate in water samples from digital images. The developed approach yielded a broad linear response ranging from 4 to 12 μg/L (R2 = 0.97) for perchlorate detection, with a limit of detection of 3.41 μg/L and a limit of quantification of 10.34 μg/L. The findings underscore the effectiveness of colorimetric analysis and digital imaging for paper-based analytical devices. The limitations of this method include the capability to detect only a single analyte and the requirement for additional steps in image processing to obtain analytical results. Future developments should focus on designing devices for simultaneous detection of multiple contaminants and exploring automated methods of image analysis.
[学术文献 ] Analysis and electroanalysis of perchlorate in water and food samples: a critical review 进入全文
Analytical Methods 期刊
Perchlorate, ClO4−, with diverse applications, has become one of the major contaminants in surface and groundwater sources. This highly soluble and stable anion poses a considerable threat to human health given that it contaminates drinking water, vegetables, milk, and other contaminated food products. ClO4− can impair the thyroid function; thus, drinking water with high levels of this anion is a severe problem worldwide. However, due to the high solubility, stability, and mobility of ClO4−, its remediation and monitoring remain a major challenge. Considering the various analytical methods, including electrochemistry, each method has advantages and disadvantages in terms of detection sensitivity, selectivity, analysis time, and cost. Also, sample preconcentration and clean-up must be performed for the analysis of more complex matrices such as food and biological samples to ensure a low detection limit and selectivity. Both ion chromatography (IC) and capillary electrophoresis (CE) coupled with electrochemical detection, in addition to liquid chromatography (LC)-mass spectrometry (MS), are expected to play key roles due to their lower detection limit with excellent sensitivities and selectivity. Herein, we also discuss the perspective on various electrode materials for the detection of ClO4− regarding whether ClO4− can be measured at the lowest levels with the highest selectivity.
