Integrative analysis in Pinus revealed long-term heat stress splicing memory.

Due to the current climate change, many studies have described main drivers in abiotic stress. Recent findings suggest that alternative splicing (AS) has a critical role in controlling plant responses to high temperature. AS is a mechanism that allows organisms to create an assortment of RNA transcripts and proteins using a single gene. However, the most important roles of AS in stress could not be rigorously addressed because research has been focused on model species, covering only a narrow phylogenetic and lifecycle spectrum. Thus, AS degree of diversification among more dissimilar taxa in heat response is still largely unknown. To fill this gap, the present study employs a systems biology approach to examine how the AS landscape responds to and 'remembers' heat stress in conifers, a group which has received little attention even though their position can solve key evolutionary questions. Contrary to angiosperms, we found that potential intron retention may not be the most prevalent type of AS. Furthermore, our integrative analysis with metabolome and proteome data places splicing as the main source of variation during the response. Finally, we evaluated possible acquired long-term splicing memory in a diverse subset of events, and although this mechanism seems to be conserved in seed plants, AS dynamics are divergent. These discoveries reveal the particular way of remembering past temperature changes in long-lived plants and open the door to include species with unique features to determine the extent of conservation in gene expression regulation.

New Insights into the Medieval Hispano-Muslim Panel Painting: The Alfarje Found in a Balearic Casal (Spain).

Hispano-Muslim culture flourished during the Middle Ages in the Iberian Peninsula and Balearic Islands. During the restoration of a Balearic nobiliary building (casal), several panels with polychrome decoration on the back side were found. They were part of an old Muslim wooden ceiling (alfarje). A multi-technique strategy including optical microscopy, infrared and µRaman spectroscopies, field emission scanning electron microscopy-X-ray microanalysis (FESEM-EDX), focused ion beam (FIB-FESEM-EDX), atomic force microscopy nanoindentation (AFM-NI), and gas chromatography-mass spectrometry (GC-MS) has been applied in the analysis of these panel paintings and has provided morphological and compositional data that have led to the identification of the materials and artistic technique as well as the alteration mechanisms due to the natural aging and the adverse conditions of conservation. As a novelty, this study has confirmed the use of indigo as a blue pigment, an unusual material in Hispano-Muslim panel painting. Apart from the notable change in the visual appearance observed in the paintings, the study has also confirmed a change in the mechanical resistance in the paint layers. These changes have been induced by the combination of the chemical and microbiological alteration mechanisms identified.

Cation and anion electrochemically assisted solid-state transformations of malachite green.

The possibility of the electrochemical promotion of different solid-to-solid transformations including the performance of successive cation and anion insertion processes has been tested using malachite green, a triphenylmethane dye, in contact with aqueous NaCl electrolyte. Electrochemical data using the voltammetry of microparticles methodology reveal significant differences with the solution phase electrochemistry of the dye. Voltammetric data, combined with atomic force microscopy, focusing ion beam-field emission scanning electron microscopy, and high-resolution field emission scanning electron microscopy permit characterization of the oxidative dissolution, oxidation with anion insertion, reduction with cation insertion and reduction with anion issue processes, whose thermochemical aspects, involving separate ion and electron transport contributions, are discussed.

Voltammetric analysis of Pinus needles with physiological, phylogenetic, and forensic applications.

Polyphenolic compounds are electrochemically active components of vegetal matter which were targeted under simple experimental conditions to produce voltammetric profiles characterizing the metabolite composition. Application to bivariate and multivariate chemometric techniques permits to discriminate the species and age of plant leaves, illustrated here for the case of six Pinus species from two different subgenera. Such responses, associated with the electrochemical oxidation of polyphenolic compounds (quercetin, gallic acid, ellagic acid, among others), define a voltammetric profile which varies systematically with the age of the leaves for the different species. The application of this methodology for phylogenetic studies, plant physiology, forensic science, and chemoecology is discussed. Graphical Abstract Image of Pinus in a typical Mediterranean forest; Courtesy of the Botanic Garden of the University of Valencia.

Screening and mapping of pigments in paintings using scanning electrochemical microscopy (SECM).

The use of the scanning electrochemical microscopy (SECM) technique for identifying and mapping of both organic and inorganic pigments in sub-microsamples from pictorial specimens is described. This methodology, inspired by the voltammetry of immobilized particles technique, permits the study of textural properties of paint layers and mapping the distribution of pigment grains upon application of different potentials to the substrate. A combination of the redox competition SECM strategy with voltammetry yields a local identification methodology for different organic and inorganic pigments in paint samples.

Dating archaeological copper/bronze artifacts by using the voltammetry of microparticles.

A method for dating copper/bronze archaeological objects aged in atmospheric environments is proposed based on the specific signals for cuprite and tenorite corrosion products measured through the voltammtry of microparticles method. The tenorite/cuprite ratio increased with the corrosion time and fitted to a potential law that yielded a calibration curve usable for dating purposes.

Ferroptosis is the key cellular process mediating Bisphenol A responses in Chlamydomonas and a promising target for enhancing microalgae-based bioremediation.

Microplastics are one of the major pollutants in aquatic environments. Among their components, Bisphenol A (BPA) is one of the most abundant and dangerous, leading to endocrine disorders deriving even in different types of cancer in mammals. However, despite this evidence, the xenobiotic effects of BPA over plantae and microalgae still need to be better understood at the molecular level. To fill this gap, we characterized the physiological and proteomic response of Chlamydomonas reinhardtii during long-term BPA exposure by analyzing physiological and biochemical parameters combined with proteomics. BPA imbalanced iron and redox homeostasis, disrupting cell function and triggering ferroptosis. Intriguingly, this microalgae defense against this pollutant is recovering at both molecular and physiological levels while starch accumulation at 72 h of BPA exposure. In this work, we addressed the molecular mechanisms involved in BPA exposure, demonstrating for the first time the induction of ferroptosis in a eukaryotic alga and how ROS detoxification mechanisms and other specific proteomic rearrangements reverted this situation. These results are of great significance not only for understanding the BPA toxicology or exploring the molecular mechanisms of ferroptosis in microalgae but also for defining novel target genes for microplastic bioremediation efficient strain development.

Electrochemical Approximation to Bronze Age Chronology via Multiple Scan Voltammetry.

Insert A multiple-scan voltammetry strategy is described and applied to a set of 107 Bronze Age and later copper/bronze objects, mainly from sites in Central Europe. This methodology allows the study of the compositional and textural properties (compactness, crystallinity, degree of hydration) of the patina to be studied from the accumulated peak current values for the characteristic signals corresponding to the reduction of cuprite and tenorite to metallic copper. A new model for the relationship between peak current and the depth reached in successive scans is presented and used to discriminate samples of different provenance and manufacturing technique, as well as their ascription to different Bronze Age periods.

Spot tests: past and present.

Microchemistry, i.e., the chemistry performed at the scale of a microgram or less, has its roots in the late eighteenth and early nineteenth centuries. In the first half of the twentieth century a wide range of spot tests have been developed. For didactic reasons, they are still part of the curriculum of chemistry students. However, they are even highly important for applied analyses in conservation of cultural heritage, food science, forensic science, clinical and pharmacological sciences, geochemistry, and environmental sciences. Modern pregnancy tests, virus tests, etc. are the most recent examples of sophisticated spot tests. The present ChemTexts contribution aims to provide an overview of the past and present of this analytical methodology.

Interplay of plastic pollution with algae and plants: hidden danger or a blessing?

In the era of plastic pollution, plants have been discarded as a system that is not affected by micro and nanoplastics, but contrary to beliefs that plants cannot absorb plastic particles, recent research proved otherwise. The presented review gives insight into known aspects of plants' interplay with plastics and how plants' ability to absorb plastic particles can be utilized to remove plastics from water and soil systems. Microplastics usually cannot be absorbed by plant root systems due to their size, but some reports indicate they might enter plant tissues through stomata. On the other hand, nanoparticles can enter plant root systems, and reports of their transport via xylem to upper plant parts have been recorded. Bioaccumulation of nanoplastics in upper plant parts is still not confirmed. The prospects of using biosystems for the remediation of soils contaminated with plastics are still unknown. However, algae could be used to degrade plastic particles in water systems through enzyme facilitated degradation processes. Considering the amount of plastic pollution, especially in the oceans, further research is necessary on the utilization of algae in plastic degradation. Special attention should be given to the research concerning utilization of algae with restricted algal growth, ensuring that a different problem is not induced, "sea blooming", during the degradation of plastics.

Dating archeological lead artifacts from measurement of the corrosion content using the voltammetry of microparticles.

A methodology for dating archeological lead artifacts based on the voltammetry of microparticles is described. This methodology is based on the comparison of the height of specific voltammetric features from PbO(2) and PbO corrosion products formed under long-term alteration conditions. Calibration of the method was performed with the help of a series of well-documented lead pieces from the funds of different museums of the Comunitat Valenciana (Spain) covering from the fifth century B.C. to present day. The variation of peak currents with the time of corrosion can be fitted to the same potential rate law as that found by Reich (α = 0.070 ± 0.005), using measurements on the Meissner fraction in the superconducting state of lead. The proposed electrochemical methodology enables the dating of archeological lead artifacts with a time-dependent uncertainty estimated to be ±150 years for the most ancient samples in this study.

Study of behaviour on simulated daylight ageing of artists' acrylic and poly(vinyl acetate) paint films.

This work proposes a multi-method approach that combines advanced microscopy (SEM/EDX, AFM) and spectroscopy (UV-vis and FTIR) techniques. This approach not only characterises the behaviour of the additives of two commercial poly(vinyl acetate) (PVAc) and acrylic emulsion paints but also simultaneously characterises the changes in chemical composition and morphology observed in the paint films as a result of ageing due to the paints being exposed to an intense source of simulated daylight. In parallel, a series of mechanical tests were performed that correlate the chemical changes in composition and the changes observed in the films' mechanical properties. This work was a comparative study between both types of acrylic and PVAc paints. The results obtained are of great interest for the modern paint conservation field as they provide valuable information on the mid- and long-term behaviours of these synthetic paints.

Multimethod analysis of Iranian Ilkhanate ceramics from the Takht-e Soleyman palace.

The present work describes an analytical study performed on several pieces of Iranian Ilkhanate glazed ceramics from the Takht-e Soleyman palace (Iran, thirteenth century). Several advanced instrumental techniques, including pyrolysis-gas chromatography-mass spectrometry, Fourier transform IR spectroscopy, light microscopy, X-ray diffraction, scanning electron microscopy-X-ray microanalysis and voltammetry of microparticles, were used. The results obtained led to identification of the chemical and mineralogical composition of the pastes and glazes and the colouring agents. Corrosion processes associated with the extreme burial conditions in which the pieces remained for centuries were characterized in some areas of the glazes. A drying oil was identified as the main component of the organic material that was used as the adhesive for the decorative gold sheets applied on the glazes. This finding is in good agreement with traditional recipes. Interestingly, this drying oil exhibits an unusual composition as the gold sheet preserved it from external ageing agents (light, atmosphere, etc.).

Identification of additives in poly(vinylacetate) artist's paints using PY-GC-MS.

Commercial poly(vinyl acetate) (PVAc) paint formulations for artists include a number of compounds in addition to the PVAc polymer and pigments to improve the physical and chemical properties of the resulting product. Among the most common additives are surfactants, coalescing agents, defoamers, freeze-thaw agents and thickeners. These products significantly influence the behaviour of the dried film. Nevertheless, they are usually difficult to detect with conventional analytical methods given their low concentration. In order to identify these additives, present in the dried film as minor components, an analytical method based on in situ thermally assisted pyrolysis-silylation gas chromatography-mass spectrometry (GC-MS) using hexamethyldisilazane as a derivatisation reagent is proposed. This method improves the conventional GC-MS analysis performed by direct pyrolysis and enables the simultaneous identification of the PVAc binding medium and the additives included by the manufacturer in the commercial paint. Five different commercial PVAc paints have been analysed, namely, armour green, burnt umber, oriental red, raw umber and white from Flashe. Internal plasticiser VeoVa consisting of C(10) fatty acids with highly branched chains has been recognised from the MS spectra. On the other hand, the differences found in the additive content of the studied paints, in particular the poly(ethylene glycol)-type surfactant, are in good agreement with their mechanical properties.

Low UV-C stress modulates Chlamydomonas reinhardtii biomass composition and oxidative stress response through proteomic and metabolomic changes involving novel signalers and effectors.

BACKGROUND: The exposure of microalgae and plants to low UV-C radiation dosages can improve their biomass composition and stress tolerance. Despite UV-C sharing these effects with UV-A/B but at much lower dosages, UV-C sensing and signal mechanisms are still mostly unknown. Thus, we have described and integrated the proteometabolomic and physiological changes occurring in Chlamydomonas reinhardtii-a simple Plantae model-into the first 24 h after a short and low-intensity UV-C irradiation in order to reconstruct the microalgae response system to this stress. RESULTS: The microalgae response was characterized by increased redox homeostasis, ROS scavenging and protein damage repair/avoidance elements. These processes were upregulated along with others related to the modulation of photosynthetic electron flux, carbon fixation and C/N metabolism. These changes, attributed to either direct UV-C-, ROS- or redox unbalances-associated damage, trigger a response process involving novel signaling intermediaries and effectors such as the translation modulator FAP204, a PP2A-like protein and a novel DYRK kinase. These elements were found linked to the modulation of Chlamydomonas biomass composition (starch accumulation) and proliferation, within an UV-C response probably modulated by different epigenetic factors. CONCLUSION: Chosen multiomics integration approach was able to describe many fast changes, including biomass composition and ROS stress tolerance, as a response to a low-intensity UV-C stress. Moreover, the employed omics and systems biology approach placed many previously unidentified protein and metabolites at the center of these changes. These elements would be promising targets for the characterization of this stress response in microalgae and plants and the engineering of more productive microalgae strains.

Multiple Biomolecule Isolation Protocol Compatible with Mass Spectrometry and Other High-Throughput Analyses in Microalgae.

Microalgae are gaining attention in industry for their high value-added biomolecules and biomass production and for studying fundamental processes in biology. The introduction of novel approaches for understanding and modeling molecular networks at different omic levels is paramount for increasing the productivity of these organisms. However, the construction of these networks requires high quality datasets with, if possible, perfectly overlapping datasets. The employ of different materials for different biomolecule isolation protocols, even if they come from the same homogenate, is one of the commonest issues affecting quality. Hence, a new method has been developed, allowing for the combined extraction of different levels including total metabolites, or their pigments or lipid fractions along nucleic acids (DNA and RNA) and/or proteins from the same sample reducing biological and time variation between levels data.

Genome-wide identification and characterization of CKIN/SnRK gene family in Chlamydomonas reinhardtii.

The SnRK (Snf1-Related protein Kinase) gene family plays an important role in energy sensing and stress-adaptive responses in plant systems. In this study, Chlamydomonas CKIN family (SnRK in Arabidopsis) was defined after a genome-wide analysis of all sequenced Chlorophytes. Twenty-two sequences were defined as plant SnRK orthologs in Chlamydomonas and classified into two subfamilies: CKIN1 and CKIN2. While CKIN1 subfamily is reduced to one conserved member and a close protein (CKIN1L), a large CKIN2 subfamily clusters both plant-like and algae specific CKIN2s. The responsiveness of these genes to abiotic stress situations was tested by RT-qPCR. Results showed that almost all elements were sensitive to osmotic stress while showing different degrees of sensibility to other abiotic stresses, as occurs in land plants, revealing their specialization and the family pleiotropy for some elements. The regulatory pathway of this family may differ from land plants since these sequences shows unique regulatory features and some of them are sensitive to ABA, despite conserved ABA receptors (PYR/PYL/RCAR) and regulatory domains are not present in this species. Core Chlorophytes and land plant showed divergent stress signalling, but SnRKs/CKINs share the same role in cell survival and stress response and adaption including the accumulation of specific biomolecules. This fact places the CKIN family as well-suited target for bioengineering-based studies in microalgae (accumulation of sugars, lipids, secondary metabolites), while promising new findings in stress biology and specially in the evolution of ABA-signalling mechanisms.

Quantitation from Tafel analysis in solid-state voltammetry. Application to the study of cobalt and copper pigments in severely damaged frescoes.

A novel method, using Tafel plots, for quantifying electroactive species in solid materials when their voltammetric signals are strongly overlapped is described. This is applied to the analysis of submicrosamples from the highly damaged frescoes painted by Palomino (1707) in the ceiling vault of the Sant Joan del Mercat church in Valencia, Spain. These paintings, which were fired in 1936, contained cobalt smalt plus azurite mixtures, this last being altered to tenorite (CuO). The reported method provides a quantitation of the cobalt smalt/azurite, tenorite/(azurite + smalt) relationships in samples, thus providing direct information on pigment dosage (smalt/azurite ratio) in pristine paintings, extent of alteration, and temperature experienced by the frescoes during the gunfire episode. Distinction between Palomino paintings and other painters was clearly obtained due to the presence of malachite in these last.

Characterization of polyvinyl resins used as binding media in paintings by pyrolysis-silylation-gas chromatography-mass spectrometry.

Polyvinyl resins, in particular poly(vinyl acetate) emulsions (PVA), are widely used in contemporary paintings as binding media, because of the optimum mechanical and optical properties these polymers confer on the paint layers. A study has been carried out to chemically characterize samples of PVA resins prepared as coating films from commercial products currently available from fine arts suppliers. For this purpose, a new method has been based on "on-line" silylation-pyrolysis using hexamethyldisilazane as derivatisation reagent in pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS). This proposed procedure leads to unambiguous identification of this type of binder and improves conventional direct Py-GC-MS. PVA media used in three contemporary paintings from a private collection and from the Museum of Fine Arts of Málaga (Spain) have been successfully identified with this procedure. As a second step of this work, a study devoted to the characterization of changes in the chemical composition of the PVA commercial products studied has been carried out. Effects induced in the specimens by three different types of artificial accelerated ageing process--thermal, UV light, and in an SO(2)-polluted chamber--were compared.

Study of ageing of ketone resins used as picture varnishes by FTIR spectroscopy, UV-Vis spectrophotometry, atomic force microscopy and scanning electron microscopy X-ray microanalysis.

This paper presents a study of thin films of the commercial ketone resins Laropal K80, Keton N and MS2A, attempting to reproduce the pictorial layers and protective finishes commonly present in contemporary paintings. Chemical and morphological changes due to the degradation effect of environmental agents have been specially considered. For this purpose, three different accelerated ageing processes were applied to a series of specimens prepared from the studied commercial products: thermal, UV light and ageing in an SO(2)-polluted chamber. Spectroscopic techniques such as FTIR spectroscopy and UV-Vis spectrophotometry were applied in combination with microscopic examination techniques, namely, AFM and scanning electron microscopy energy dispersive X-ray microanalysis (SEM-EDX). Chemical changes due to UV light and thermal ageing are in good agreement with those previously reported in the literature. Bleaching exhibited by the three commercial products after exposure to a SO(2)-saturated atmosphere has been related to the diffusion of SO(2)-rich water vapour into the film. This effect was particularly strong in the MS2A resin due to the higher content of hydroxyl groups in this product.