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1.
Sci Rep ; 12(1): 18988, 2022 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-36348043

RESUMO

Microalgae have recently emerged as a key research topic, especially as biological models. Among them, the green alga Klebsormidium nitens, thanks to its particular adaptation to environmental stresses, represents an interesting photosynthetic eukaryote for studying the transition stages leading to the colonization of terrestrial life. The tolerance to different stresses is manifested by changes in gene expression, which can be monitored by quantifying the amounts of transcripts by RT-qPCR. The identification of optimal reference genes for experiment normalization was therefore necessary. In this study, using four statistical algorithms followed by the RankAggreg package, we determined the best reference gene pairs suitable for normalizing RT-qPCR data in K. nitens in response to three abiotic stresses: high salinity, PEG-induced dehydration and heat shock. Based on these reference genes, we were able to identify marker genes in response to the three abiotic stresses in K. nitens.


Assuntos
Regulação da Expressão Gênica de Plantas , Estreptófitas , Estresse Fisiológico/genética , Estreptófitas/genética , Genes de Plantas , Salinidade , Reação em Cadeia da Polimerase em Tempo Real , Padrões de Referência , Perfilação da Expressão Gênica
2.
Curr Biol ; 32(20): 4473-4482.e7, 2022 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-36055238

RESUMO

The evolution of streptophytes had a profound impact on life on Earth. They brought forth those photosynthetic eukaryotes that today dominate the macroscopic flora: the land plants (Embryophyta).1 There is convincing evidence that the unicellular/filamentous Zygnematophyceae-and not the morphologically more elaborate Coleochaetophyceae or Charophyceae-are the closest algal relatives of land plants.2-6 Despite the species richness (>4,000), wide distribution, and key evolutionary position of the zygnematophytes, their internal phylogeny remains largely unresolved.7,8 There are also putative zygnematophytes with interesting body plan modifications (e.g., filamentous growth) whose phylogenetic affiliations remain unknown. Here, we studied a filamentous green alga (strain MZCH580) from an Austrian peat bog with central or parietal chloroplasts that lack discernible pyrenoids. It represents Mougeotiopsis calospora PALLA, an enigmatic alga that was described more than 120 years ago9 but never subjected to molecular analyses. We generated transcriptomic data of M. calospora strain MZCH580 and conducted comprehensive phylogenomic analyses (326 nuclear loci) for 46 taxonomically diverse zygnematophytes. Strain MZCH580 falls in a deep-branching zygnematophycean clade together with some unicellular species and thus represents a formerly unknown zygnematophycean lineage with filamentous growth. Our well-supported phylogenomic tree lets us propose a new five-order system for the Zygnematophyceae and provides evidence for at least five independent origins of true filamentous growth in the closest algal relatives of land plants. This phylogeny provides a robust and comprehensive framework for performing comparative analyses and inferring the evolution of cellular traits and body plans in the closest relatives of land plants.


Assuntos
Carofíceas , Embriófitas , Estreptófitas , Filogenia , Evolução Biológica , Embriófitas/genética , Carofíceas/genética , Plantas , Solo
3.
Plant Physiol ; 190(3): 1588-1608, 2022 10 27.
Artigo em Inglês | MEDLINE | ID: mdl-35993883

RESUMO

Charophytes (Streptophyta) represent a diverse assemblage of extant green algae that are the sister lineage to land plants. About 500-600+ million years ago, a charophyte progenitor successfully colonized land and subsequently gave rise to land plants. Charophytes have diverse but relatively simple body plans that make them highly attractive organisms for many areas of biological research. At the cellular level, many charophytes have been used for deciphering cytoskeletal networks and their dynamics, membrane trafficking, extracellular matrix secretion, and cell division mechanisms. Some charophytes live in challenging habitats and have become excellent models for elucidating the cellular and molecular effects of various abiotic stressors on plant cells. Recent sequencing of several charophyte genomes has also opened doors for the dissection of biosynthetic and signaling pathways. While we are only in an infancy stage of elucidating the cell biology of charophytes, the future application of novel analytical methodologies in charophyte studies that include a broader survey of inclusive taxa will enhance our understanding of plant evolution and cell dynamics.


Assuntos
Carofíceas , Clorófitas , Estreptófitas , Filogenia , Plantas/genética , Evolução Biológica
4.
Protoplasma ; 259(5): 1157-1174, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34939169

RESUMO

The streptophyte algal class Zygnematophyceae is the closest algal sister lineage to land plants. In nature, Zygnematophyceae can grow in both terrestrial and freshwater habitats and how they do this is an important unanswered question. Here, we studied what happens to the zygnematophyceaen alga Mougeotia sp., which usually occurs in permanent and temporary freshwater bodies, when it is shifted to liquid growth conditions after growth on a solid substrate. Using global differential gene expression profiling, we identified changes in the core metabolism of the organism interlinked with photosynthesis; the latter went hand in hand with measurable impact on the photophysiology as assessed via pulse amplitude modulation (PAM) fluorometry. Our data reveal a pronounced change in the overall physiology of the alga after submergence and pinpoint candidate genes that play a role. These results provide insight into the importance of photophysiological readjustment when filamentous Zygnematophyceae transition between terrestrial and aquatic habitats.


Assuntos
Mougeotia , Estreptófitas , Expressão Gênica , Mougeotia/genética , Fotossíntese/genética , Filogenia , Plantas/metabolismo , Estreptófitas/fisiologia
5.
BMC Plant Biol ; 21(1): 322, 2021 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-34225654

RESUMO

BACKGROUND: Flexibility of plant metabolism is supported by redox regulation of enzymes via posttranslational modification of cysteine residues, especially in plastids. Here, the redox states of cysteine residues are partly coupled to the thioredoxin system and partly to the glutathione pool for reduction. Moreover, several plastid enzymes involved in reactive oxygen species (ROS) scavenging and damage repair draw electrons from glutathione. In addition, cysteine residues can be post-translationally modified by forming a mixed disulfide with glutathione (S-glutathionylation), which protects thiol groups from further oxidation and can influence protein activity. However, the evolution of the plastid glutathione-dependent redox network in land plants and the conservation of cysteine residues undergoing S-glutathionylation is largely unclear. RESULTS: We analysed the genomes of nine representative model species from streptophyte algae to angiosperms and found that the antioxidant enzymes and redox proteins belonging to the plastid glutathione-dependent redox network are largely conserved, except for lambda- and the closely related iota-glutathione S-transferases. Focussing on glutathione-dependent redox modifications, we screened the literature for target thiols of S-glutathionylation, and found that 151 plastid proteins have been identified as glutathionylation targets, while the exact cysteine residue is only known for 17% (26 proteins), with one or multiple sites per protein, resulting in 37 known S-glutathionylation sites for plastids. However, 38% (14) of the known sites were completely conserved in model species from green algae to flowering plants, with 22% (8) on non-catalytic cysteines. Variable conservation of the remaining sites indicates independent gains and losses of cysteines at the same position during land plant evolution. CONCLUSIONS: We conclude that the glutathione-dependent redox network in plastids is highly conserved in streptophytes with some variability in scavenging and damage repair enzymes. Our analysis of cysteine conservation suggests that S-glutathionylation in plastids plays an important and yet under-investigated role in redox regulation and stress response.


Assuntos
Glutationa/metabolismo , Plastídeos/metabolismo , Embriófitas/metabolismo , Evolução Molecular , Oxirredução , Filogenia , Estreptófitas/metabolismo
6.
Plant J ; 107(4): 975-1002, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34165823

RESUMO

Land plants constantly respond to fluctuations in their environment. Part of their response is the production of a diverse repertoire of specialized metabolites. One of the foremost sources for metabolites relevant to environmental responses is the phenylpropanoid pathway, which was long thought to be a land-plant-specific adaptation shaped by selective forces in the terrestrial habitat. Recent data have, however, revealed that streptophyte algae, the algal relatives of land plants, have candidates for the genetic toolkit for phenylpropanoid biosynthesis and produce phenylpropanoid-derived metabolites. Using phylogenetic and sequence analyses, we here show that the enzyme families that orchestrate pivotal steps in phenylpropanoid biosynthesis have independently undergone pronounced radiations and divergence in multiple lineages of major groups of land plants; sister to many of these radiated gene families are streptophyte algal candidates for these enzymes. These radiations suggest a high evolutionary versatility in the enzyme families involved in the phenylpropanoid-derived metabolism across embryophytes. We suggest that this versatility likely translates into functional divergence, and may explain the key to one of the defining traits of embryophytes: a rich specialized metabolism.


Assuntos
Enzimas/metabolismo , Fenilpropionatos/metabolismo , Filogenia , Proteínas de Plantas/metabolismo , Oxirredutases do Álcool/genética , Oxirredutases do Álcool/metabolismo , Sistema Enzimático do Citocromo P-450/genética , Sistema Enzimático do Citocromo P-450/metabolismo , Enzimas/genética , Metiltransferases/genética , Metiltransferases/metabolismo , Família Multigênica , Fenilalanina Amônia-Liase/genética , Fenilalanina Amônia-Liase/metabolismo , Proteínas de Plantas/genética , Metabolismo Secundário , Estreptófitas/genética , Estreptófitas/metabolismo
7.
J Phycol ; 57(4): 1151-1166, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-33529378

RESUMO

Commercial cultivation of eukaryotic microalgae has so far employed a unicellular form of species only (e.g., Chlorella pyrenoidosa, Dunaliella salina, and Haematococcus pluvialis). In this study, we assessed the feasibility of using the filamentous eukaryotic microalga Klebsormidium sp. LGX80 as a new cultivar for biomass and lipid production. The effects of different forms and concentrations of nitrogen on growth and lipid production of Klebsormidium sp. LGX80 were studied by using a glass column (ø4.5 × 60 cm) photobioreactor under laboratory conditions. Growth and lipid production of the new strain were further evaluated in an outdoor pilot-scale tubular photobioreactor. The results showed that when supplied with urea as a source of nitrogen Klebsormidium sp. LGX80 yielded a final biomass concentration of 8.49 ± 0.10 g · L-1 in which a cellular lipid content was 59.2 ± 0.4% DW. Under such conditions, the biomass and lipid productivities were 471.7 ± 5.9 and 248.1 ± 0.0 mg · L-1  · d-1 , respectively. Fatty acid analysis revealed that the main fatty acids of Klebsormidium sp. LGX80 were palmitic acid (C16:0), linoleic acid (C18:2ω6), and linolenic acid (C18:3ω3), of which linoleic acid (C18:2ω6) accounted for up to 67.5 ± 0.1% of total fatty acids. When grown outdoors in a 13,000-L tubular photobioreactor with an initial nitrogen concentration of 3 mM urea, Klebsormidium sp. LGX80 reached the highest biomass concentration of 2.63 ± 0.09 g · L-1 with the cells containing 38.0 ± 0.5% lipids (% DW), resulting in the volumetric biomass and lipid productivities of 147.2 ± 3.6 and 37.9 ± 0.9 mg · L-1  d-1 , respectively. The results of light:dark cycle experiment showed that a durative and prolonged light irradiation hindered the biosynthesis of chlorophyll a and chlorophyll b in the cells, but promoted the carotenoid accumulation. These results suggested that Klebsormidium sp. LGX80 can be a potential oleaginous filamentous microalga for commercial production of microalgal oils.


Assuntos
Chlorella , Microalgas , Estreptófitas , Biomassa , Clorofila A , Ácidos Graxos , Lipídeos
8.
Plant Cell Physiol ; 62(3): 436-446, 2021 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-33416834

RESUMO

Land plants evolved from a single group of streptophyte algae. One of the key factors needed for adaptation to a land environment is the modification in the peripheral antenna systems of photosystems (PSs). Here, the PSs of Mesostigma viride, one of the earliest-branching streptophyte algae, were analyzed to gain insight into their evolution. Isoform sequencing and phylogenetic analyses of light-harvesting complexes (LHCs) revealed that M. viride possesses three algae-specific LHCs, including algae-type LHCA2, LHCA9 and LHCP, while the streptophyte-specific LHCB6 was not identified. These data suggest that the acquisition of LHCB6 and the loss of algae-type LHCs occurred after the M. viride lineage branched off from other streptophytes. Clear-native (CN)-polyacrylamide gel electrophoresis (PAGE) resolved the photosynthetic complexes, including the PSI-PSII megacomplex, PSII-LHCII, two PSI-LHCI-LHCIIs, PSI-LHCI and the LHCII trimer. Results indicated that the higher-molecular weight PSI-LHCI-LHCII likely had more LHCII than the lower-molecular weight one, a unique feature of M. viride PSs. CN-PAGE coupled with mass spectrometry strongly suggested that the LHCP was bound to PSII-LHCII, while the algae-type LHCA2 and LHCA9 were bound to PSI-LHCI, both of which are different from those in land plants. Results of the present study strongly suggest that M. viride PSs possess unique features that were inherited from a common ancestor of streptophyte and chlorophyte algae.


Assuntos
Complexos de Proteínas Captadores de Luz/metabolismo , Complexo de Proteínas do Centro de Reação Fotossintética/metabolismo , Estreptófitas/metabolismo , Centrifugação com Gradiente de Concentração , Eletroforese em Gel de Poliacrilamida , Complexos de Proteínas Captadores de Luz/genética , Complexos de Proteínas Captadores de Luz/isolamento & purificação , Espectrometria de Massas , Complexo de Proteínas do Centro de Reação Fotossintética/genética , Complexo de Proteínas do Centro de Reação Fotossintética/isolamento & purificação , Complexo de Proteína do Fotossistema I/genética , Complexo de Proteína do Fotossistema I/metabolismo , Complexo de Proteína do Fotossistema II/genética , Complexo de Proteína do Fotossistema II/metabolismo , Filogenia , Análise de Sequência de DNA , Estreptófitas/genética
9.
Nucleus ; 11(1): 330-346, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33161800

RESUMO

The functional organization of the plant nuclear envelope is gaining increasing attention through new connections made between nuclear envelope-associated proteins and important plant biological processes. Animal nuclear envelope proteins play roles in nuclear morphology, nuclear anchoring and movement, chromatin tethering and mechanical signaling. However, how these roles translate to functionality in a broader biological context is often not well understood. A surprising number of plant nuclear envelope-associated proteins are plant-unique, suggesting that separate functionalities evolved after the split of Opisthokonta and Streptophyta. Significant progress has now been made in discovering broader biological roles of plant nuclear envelope proteins, increasing the number of known plant nuclear envelope proteins, and connecting known proteins to chromatin organization, gene expression, and the regulation of nuclear calcium. The interaction of viruses with the plant nuclear envelope is another emerging theme. Here, we survey the recent developments in this still relatively new, yet rapidly advancing field.


Assuntos
Proteínas de Membrana/metabolismo , Membrana Nuclear/metabolismo , Proteínas de Plantas/metabolismo , Estreptófitas/metabolismo , Proteínas de Membrana/genética , Membrana Nuclear/genética , Proteínas de Plantas/genética , Estreptófitas/genética
10.
Protist ; 171(5): 125768, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-33126022

RESUMO

Microbial parasites have only recently been included in planktonic food web studies, but their functional role in conveying dietary energy still remains to be elucidated. Parasitic fungi (chytrids) infecting phytoplankton may constitute an alternative trophic link and promote organic matter transfer through the production of dissemination zoospores. Particularly, during proliferation of inedible or toxic algal species, such as large Cyanobacteria fostered by global warming, parasites can constitute an alternative trophic link providing essential dietary nutrients that support somatic growth and reproduction of consumers. Using phytoplankton-parasites associations grown under laboratory controlled conditions we assessed the fatty acids and biochemical composition of species with different nutritional quality and followed the metabolic pathway from the algal host and their parasites zoospores using compound-specific stable isotope analysis. This study demonstrated that chytrids are trophic upgraders able to retain essential nutrients that can be transferred to upper trophic levels both in terms of organic matter quantity and nutritional quality. Through the production of zoospores, nutritionally important long-chain polyunsaturated fatty acids that can be consequently assimilated by consumers. We conclude that parasitism at the base of aquatic food webs may represent a crucial trophic link for dietary nutrients and essential biomolecules alternative to herbivory or bacterivory, which can be particularly crucial during the proliferation of inedible or nutritionally inadequate algal species fostered by climate change.


Assuntos
Cadeia Alimentar , Plâncton/metabolismo , Quitridiomicetos/química , Quitridiomicetos/metabolismo , Diatomáceas/química , Diatomáceas/metabolismo , Ácidos Graxos/análise , Plâncton/parasitologia , Estreptófitas/química , Estreptófitas/metabolismo
11.
Pharm Res ; 37(8): 152, 2020 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-32700034

RESUMO

PURPOSE: Anthocyanins (ACNs) are polyphenols that might reduce pathological processes associated with type 2 diabetes mellitus and other chronic diseases, but their bioavailability is still controversial. In this study, the metabolic activity of oral delivery of ACN-loaded niosomes was investigated and evaluated in a diet-induced obesity (DIO) mice model. METHODS: ACNs extracted from Vaccinium Meridionale by the supercritical fluid extraction method were loaded in niosomes. The niosomal formulation was physically characterized and further administrated in drinking water to obese, insulin resistant mouse. We evaluated the effect of ACN loaded niosomes on hyperglycemia, glucose and insulin intolerance and insulin blood levels in C57BL/6 J mice fed with a high-fat diet. RESULTS: The ACN-loaded particles were moderately monodisperse, showed a negative surface charge and 57% encapsulation efficiency. The ACN-loaded niosomes ameliorated the insulin resistance and glucose intolerance in the DIO mice model. Additionally, they reduced animal weight and plasma insulin, glucose, leptin and total cholesterol levels in obese mice. CONCLUSION: ACN-loaded niosomes administration, as a functional drink, had a beneficial effect on the reversal of metabolic abnormalities associated with obesity.


Assuntos
Antocianinas/química , Diabetes Mellitus Tipo 2/tratamento farmacológico , Hipoglicemiantes/química , Lipossomos/química , Nanocápsulas/química , Extratos Vegetais/química , Estreptófitas/química , Animais , Antocianinas/administração & dosagem , Glicemia/efeitos dos fármacos , Peso Corporal/efeitos dos fármacos , Colesterol/sangue , Colesterol/metabolismo , Diabetes Mellitus Experimental , Dieta Hiperlipídica , Composição de Medicamentos , Liberação Controlada de Fármacos , Humanos , Hipoglicemiantes/administração & dosagem , Insulina/sangue , Insulina/metabolismo , Insulina/farmacologia , Resistência à Insulina , Leptina/sangue , Leptina/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Camundongos Obesos , Obesidade/tratamento farmacológico , Extratos Vegetais/administração & dosagem
13.
J Exp Bot ; 71(11): 3279-3286, 2020 06 11.
Artigo em Inglês | MEDLINE | ID: mdl-32270175

RESUMO

Land plants with elaborated three-dimensional (3D) body plans have evolved from streptophyte algae. The streptophyte algae are known to exhibit varying degrees of morphological complexity, ranging from single-celled flagellates to branched macrophytic forms exhibiting tissue-like organization. In this review, I discuss mechanisms by which, during evolution, filamentous algae may have gained 2D and eventually 3D body plans. There are, in principle, two mechanisms by which an additional dimension may be added to an existing algal filament or cell layer: first, by tip growth-mediated branching. An example of this mechanism is the emergence and polar expansion of root hairs from land plants. The second possibility is the rotation of the cell division plane. In this case, the plane of the forthcoming cell division is rotated within the parental cell wall. This type of mechanism corresponds to the formative cell division seen in meristems of land plants. This literature review shows that of the extant streptophyte algae, the Charophyceae and Coleochaetophyceae are capable of performing both mechanisms, while the Zygnematophyceae (the actual sister to land plants) show tip growth-based branching only. I finally discuss how apical cells with two or three cutting faces, as found in mosses, may have evolved from algal ancestors.


Assuntos
Embriófitas , Estreptófitas , Evolução Biológica , Filogenia , Plantas
14.
J Exp Bot ; 71(11): 3270-3278, 2020 06 11.
Artigo em Inglês | MEDLINE | ID: mdl-32107542

RESUMO

The present review summarizes the effects of desiccation in streptophyte green algae, as numerous experimental studies have been performed over the past decade particularly in the early branching streptophyte Klebsormidium sp. and the late branching Zygnema circumcarinatum. The latter genus gives its name to the Zygenmatophyceae, the sister group to land plants. For both organisms, transcriptomic investigations of desiccation stress are available, and illustrate a high variability in the stress response depending on the conditions and the strains used. However, overall, the responses of both organisms to desiccation stress are very similar to that of land plants. We highlight the evolution of two highly regulated protein families, the late embryogenesis abundant (LEA) proteins and the major intrinsic protein (MIP) family. Chlorophytes and streptophytes encode LEA4 and LEA5, while LEA2 have so far only been found in streptophyte algae, indicating an evolutionary origin in this group. Within the MIP family, a high transcriptomic regulation of a tonoplast intrinsic protein (TIP) has been found for the first time outside the embryophytes in Z. circumcarinatum. The MIP family became more complex on the way to terrestrialization but simplified afterwards. These observations suggest a key role for water transport proteins in desiccation tolerance of streptophytes.


Assuntos
Clorófitas , Embriófitas , Estreptófitas , Clorófitas/genética , Dessecação , Desenvolvimento Embrionário , Filogenia , Estreptófitas/genética
15.
J Exp Bot ; 71(11): 3296-3304, 2020 06 11.
Artigo em Inglês | MEDLINE | ID: mdl-32076703

RESUMO

The class of conjugating green algae, Zygnematophyceae (Conjugatophyceae), is extremely rich in species and has attracted the interest of phycologists for a long time. It is now widely accepted that this class of charophyte algae holds a key position in the phylogenetic tree of streptophytes, where they represent the closest relatives to all land plants (embryophytes). It is increasingly evident that robust model plants that can be easily cultivated and genetically transformed are necessary to better understand the process of terrestrialization and the related molecular, cellular, and physiological adaptations. Living algae collections play an important role, not only for phylogenomic-based taxonomy but also for screening for suitable model organisms. For this review, we screened six major public algae collections for Zygnematophyceae strains and established a cumulative list comprising 738 different taxa (including species, subspecies, varieties, and forms). From the described biodiversity with 8883 registered taxa (AlgaeBase) the cultured Zygnematophyceae taxa worldwide cover only ~8.3%. We review the past research on this clade of algae and discuss it from the perspective of establishing a model organism. We present data on the life cycle of the genera Micrasterias and Spirogyra, representing the orders Desmidiales and Zygnematales, and outline the current status of genetic transformation of Zygnematophyceae algae and future research perspectives.


Assuntos
Clorófitas , Embriófitas , Estreptófitas , Adaptação Fisiológica , Clorófitas/genética , Filogenia
16.
Philos Trans A Math Phys Eng Sci ; 378(2167): 20190447, 2020 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-32008452

RESUMO

Superhydrophobicity is a physical feature of surfaces occurring in many organisms and has been applied (e.g. lotus effect) in bionic technical applications. Some aquatic species are able to maintain persistent air layers under water (Salvinia effect) and thus become increasingly interesting for drag reduction and other 'bioinspired' applications. However, another feature of superhydrophobic surfaces, i.e. the adsorption (not absorption) and subsequent superficial transportation and desorption capability for oil, has been neglected. Intense research is currently being carried out on oil-absorbing bulk materials like sponges, focusing on oleophilic surfaces and meshes to build membranes for oil-water separation. This requires an active pumping of oil-water mixtures onto or through the surface. Here, we present a novel passive, self-driven technology to remove oil from water surfaces. The oil is adsorbed onto a superhydrophobic material (e.g. textiles) and transported on its surface. Vertical and horizontal transportation is possible above or below the oil-contaminated water surface. The transfer in a bioinspired novel bionic oil adsorber is described. The oil is transported into a container and thus removed from the surface. Prototypes have proven to be an efficient and environmentally friendly technology to clean oil spills from water without chemicals or external energy supply. This article is part of the theme issue 'Bioinspired materials and surfaces for green science and technology (part 3)'.


Assuntos
Adsorção , Biodegradação Ambiental , Técnicas de Química Analítica/métodos , Óleos/análise , Água/análise , Araceae , Materiais Biocompatíveis , Brassicaceae , Cistaceae , Cistus , Simulação por Computador , Elastômeros , Desenho de Equipamento , Química Verde , Interações Hidrofóbicas e Hidrofílicas , Poluição por Petróleo , Robótica , Estreptófitas , Propriedades de Superfície , Têxteis , Fatores de Tempo , Viscosidade
17.
J Phycol ; 56(3): 649-661, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-31957017

RESUMO

Members of the cosmopolitan streptophycean genus Klebsormidium live in various habitats, including sand dunes and polar/alpine environments. To survive in these harsh conditions they must possess an array of adaptive physiological and structural mechanisms, for example, to deal with chilling and photochilling stresses. Since these mechanisms have not been studied in detail, the objectives of this study were (i) to determine the physiological and biochemical responses of Klebsormidium cf. flaccidum (K. cf. flaccidum) to chilling (low temperature [LT]) and photochilling (LT in combination with high light [HL]) stresses; and (ii) to understand the cross-link between biochemical parameters and cellular ultrastructural changes. The results indicated that 5°C is a temperature threshold (i.e., at 5°C) but not at higher temperatures, physiological changes were observed (Fv /Fm and ETR decreased and energy-partitioning distribution changed, with an increase in Y[NPQ] under LT and an increase in Y[NO] under HL-LT). Also, pigment contents changed significantly, with increased concentrations of photoprotective pigments such as antheraxanthin, zeaxanthin, and total carotenes. All of these responses occurred under LT and, to a greater extent, under LT-HL, indicating that the two stresses (temperature and light) are additive. The cold treatment applied here induced the formation of spores under both LL and HL. The degree of photoinhibition was higher in spores than in vegetative cells, indicating that spores are less susceptible to photodamage. This study demonstrated a broad acclimation potential in different developmental stages of K. cf. flaccidum, which helps to explain the ecological success of this genus.


Assuntos
Estreptófitas , Temperatura Baixa , Ecossistema , Fotossíntese , Temperatura
19.
J Phycol ; 56(1): 217-232, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31610035

RESUMO

The green algal genus Cylindrocystis is widespread in various types of environments, including extreme habitats. However, very little is known about its diversity, especially in polar regions. In the present study, we isolated seven new Cylindrocystis-like strains from terrestrial and freshwater habitats in Svalbard (High Arctic). We aimed to compare the new isolates on a molecular (rbcL and 18S rDNA), morphological (light and confocal laser scanning microscopy), and cytological (Raman microscopy) basis. Our results demonstrated that the Arctic Cylindrocystis were not of a monophyletic origin and that the studied strains clustered within two clades (tentatively named the soil and freshwater/glacier clades) and four separate lineages. Morphological data (cell size, shape, and chloroplast morphology) supported the presence of several distinct taxa among the new isolates. Moreover, the results showed that the Arctic Cylindrocystis strains were closely related to strains originating from the temperate zone, indicating high ecological versatility and successful long-distance dispersal of the genus. Large amounts of inorganic polyphosphate (polyP) grains were detected within the chloroplasts of the cultured Arctic Cylindrocystis strains, suggesting effective luxury uptake of phosphorus. Additionally, various intracellular structures were identified using Raman microscopy and cytochemical and fluorescent staining. This study represents the first attempt to combine molecular, morphological, ecological, and biogeographical data for Arctic Cylindrocystis. Our novel cytological observations partially explain the success of Cylindrocystis-like microalgae in polar regions.


Assuntos
Clorófitas , Estreptófitas , Regiões Árticas , Filogenia , Polifosfatos , Svalbard
20.
Chin J Integr Med ; 26(3): 205-211, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30591962

RESUMO

OBJECTIVE: To observe the effect and molecular mechanism of ethyl acetate extract of Sceptridium ternatum (STE) on the monocrotaline (MCT)-induced pulmonary arterial hypertension (PAH). METHODS: The main chemical components of Sceptridium ternatum were determined, and the effects in PAH rats were observed. A total of 140 Sprague Dawley rats were randomly and equally divided into the normal group, the model group, the Bosentan group, and the STE groups (2.5, 5, 10 g/kg) by the random number table method. The characteristic indicators of PAH were measured, and immunohistochemistry was used to observe the lung tissue of rats. Morphological changes of the lung tissue were observed under the light microscope. RESULTS: Compared with the normal group, rats in the model group showed a significant increase in right ventricular free wall thickness (RVFWT), mean pulmonary arterial pressure (mPAP), mean right ventricular pressure (mRVP), max right ventricular pressure (max RVP), weight of right ventricle (RV), and lung index (LI), while a significant decrease in pulmonary artery acceleration time (PAAT, P<0.01). Compared with the model group, rats treated with STE had a significant decrease of RVFWT, mPAP, mRVP, max RVP, and RV, while a significant increase of PAAT (P<0.01). After injection of MCT, nuclear factor- κB (NF- κB) p65 and α -smooth muscle actin (α -SMA) expression levels were up-regulated, and on the contrary, the treatment groups showed a significant down-regulation without dose-dependent trend. CONCLUSIONS: STE can relieve the PAH in rats. STE may relieve pulmonary vascular disease and pulmonary injury by down-regulating the expression of NF- κB p65 and α -SMA.


Assuntos
Extratos Vegetais/farmacologia , Hipertensão Arterial Pulmonar/prevenção & controle , Estreptófitas/química , Acetatos , Animais , Modelos Animais de Doenças , Feminino , Pulmão/efeitos dos fármacos , Masculino , Monocrotalina , Extratos Vegetais/química , Ratos , Ratos Sprague-Dawley
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