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1.
Int J Mol Sci ; 25(9)2024 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-38732217

RESUMO

The Euganean Thermal District, situated in North-East Italy, is one of Europe's largest and oldest thermal centres. The topical application of its therapeutic thermal muds is recognised by the Italian Health System as a beneficial treatment for patients suffering from arthro-rheumatic diseases. Polysaccharides produced by the mud microbiota have been recently identified as anti-inflammatory bioactive molecules. In this paper we analysed the efficacy of Microbial-Polysaccharides (M-PS) derived from mature muds obtained at different maturation temperatures, both within and outside the codified traditional mud maturation range. M-PSs were extracted from six mature muds produced by five spas of the Euganean Thermal District and investigated for their chemical properties, monosaccharide composition and in vivo anti-inflammatory potential, using the zebrafish model organism. Additionally, mature muds were characterized for their microbiota composition using Next-Generation Sequencing. The results showed that all M-PSs exhibit similar anti-inflammatory potential, referable to their comparable chemical composition. This consistency was observed despite changes in cyanobacteria populations, suggesting a possible role of the entire microbial community in shaping the properties of these biomolecules. These findings highlight the importance of scientific research in untangling the origins of the therapeutic efficacy of Euganean Thermal muds in the treatment of chronic inflammatory conditions.


Assuntos
Anti-Inflamatórios , Peixe-Zebra , Animais , Anti-Inflamatórios/farmacologia , Anti-Inflamatórios/química , Itália , Polissacarídeos Bacterianos/farmacologia , Polissacarídeos Bacterianos/química , Microbiota/efeitos dos fármacos , Polissacarídeos/farmacologia , Polissacarídeos/química , Polissacarídeos/isolamento & purificação , Peloterapia
2.
Physiol Plant ; 173(3): 805-817, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34171145

RESUMO

Eukaryotic algae are photosynthetic organisms capable of exploiting sunlight to fix carbon dioxide into biomass with highly variable genetic and metabolic features. Information on algae metabolism from different species is inhomogeneous and, while green algae are, in general, more characterized, information on red algae is relatively scarce despite their relevant position in eukaryotic algae diversity. Within red algae, the best-known species are extremophiles or multicellular, while information on mesophilic unicellular organisms is still lacunose. Here, we investigate the photosynthetic properties of a recently isolated seawater unicellular mesophilic red alga, Dixoniella giordanoi. Upon exposure to different illuminations, D. giordanoi shows the ability to acclimate, modulate chlorophyll content, and re-organize thylakoid membranes. Phycobilisome content is also largely regulated, leading to almost complete disassembly of this antenna system in cells grown under intense illumination. Despite the absence of a light-induced xanthophyll cycle, cells accumulate zeaxanthin upon prolonged exposure to strong light, likely contributing to photoprotection. D. giordanoi cells show the ability to perform cyclic electron transport that is enhanced under strong illumination, likely contributing to the protection of Photosystem I from over-reduction and enabling cells to survive PSII photoinhibition without negative impact on growth.


Assuntos
Complexo de Proteína do Fotossistema II , Rodófitas , Aclimatação , Clorofila , Luz , Fotossíntese , Complexo de Proteína do Fotossistema II/metabolismo , Rodófitas/metabolismo
3.
Plant Physiol ; 176(3): 2305-2314, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29284743

RESUMO

Photosynthetic organisms use sunlight as the primary source of energy to support their metabolism. In eukaryotes, reactions responsible of the conversion of light into chemical energy occur in specific organelles, the chloroplasts. In this study, we showed that mitochondria also have a seminal influence on cells' energy metabolism and on photosynthetic reactions. This is illustrated by the observation that the strong photosensitivity of Chlamydomonas reinhardtii cells depleted of the chloroplast protein PGRL1 was rescued by the introduction of a mitochondrial mutation affecting respiratory complex I. Functional analysis showed that such a reduced respiratory activity influenced chloroplast electron transport with consequent overreduction of plastoquinone and donor-side limitation of photosystem I (PSI). As a consequence, damage due to excess light affected more photosystem II (PSII) rather than PSI. Double mutant cells are able to grow under excess illumination, while single pgrl1 are not, thanks to the presence of an efficient repair mechanism of PSII. These results also underline the seminal biological relevance of the regulation of electron transport reactions within the photosynthetic complexes. Photosynthetic organisms evolved a strategy to respond to excess light where damage is targeting preferentially to a specific complex, PSII. Cells are able to endure extensive damage targeting this complex thanks to an efficient repair mechanisms, while if PSI is affected, there are drastic consequences on growth.


Assuntos
Chlamydomonas reinhardtii/fisiologia , Mitocôndrias/metabolismo , Fotossíntese/fisiologia , Cloroplastos/genética , Cloroplastos/metabolismo , Transporte de Elétrons/genética , Luz , Mutação , NADH Desidrogenase/genética , NADH Desidrogenase/metabolismo , Complexo de Proteína do Fotossistema I/metabolismo , Complexo de Proteína do Fotossistema II/metabolismo , Plastoquinona/metabolismo
4.
Photosynth Res ; 129(3): 291-305, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27448115

RESUMO

Nannochloropsis is an eukaryotic alga of the phylum Heterokonta, originating from a secondary endosymbiotic event. In this work, we investigated how the photosynthetic apparatus responds to growth in different light regimes in Nannochloropsis gaditana. We found that intense illumination induces the decrease of both photosystem I and II contents and their respective antenna sizes. Cells grown in high light showed a larger capacity for electron transport, with enhanced cyclic electron transport around photosystem I, contributing to photoprotection from excess illumination. Even when exposed to excess light intensities for several days, N. gaditana cells did not activate constitutive responses such as nonphotochemical quenching and the xanthophyll cycle. These photoprotection mechanisms in N. gaditana thus play a role in acclimation to fast changes in illumination within a time range of minutes, while regulation of the electron flow capacity represents a long-term response to prolonged exposure to excess light.


Assuntos
Complexo de Proteína do Fotossistema I/metabolismo , Complexo de Proteína do Fotossistema II/metabolismo , Estramenópilas/fisiologia , Aclimatação , Transporte de Elétrons/efeitos da radiação , Luz , Fotossíntese/efeitos da radiação , Estramenópilas/efeitos da radiação , Xantofilas/metabolismo
5.
J Exp Bot ; 66(19): 5753-67, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26093144

RESUMO

The fdl1-1 mutation, caused by an Enhancer/Suppressor mutator (En/Spm) element insertion located in the third exon of the gene, identifies a novel gene encoding ZmMYB94, a transcription factor of the R2R3-MYB subfamily. The fdl1 gene was isolated through co-segregation analysis, whereas proof of gene identity was obtained using an RNAi strategy that conferred less severe, but clearly recognizable specific mutant traits on seedlings. Fdl1 is involved in the regulation of cuticle deposition in young seedlings as well as in the establishment of a regular pattern of epicuticular wax deposition on the epidermis of young leaves. Lack of Fdl1 action also correlates with developmental defects, such as delayed germination and seedling growth, abnormal coleoptile opening and presence of curly leaves showing areas of fusion between the coleoptile and the first leaf or between the first and the second leaf. The expression profile of ZmMYB94 mRNA-determined by quantitative RT-PCR-overlaps the pattern of mutant phenotypic expression and is confined to a narrow developmental window. High expression was observed in the embryo, in the seedling coleoptile and in the first two leaves, whereas RNA level, as well as phenotypic defects, decreases at the third leaf stage. Interestingly several of the Arabidopsis MYB genes most closely related to ZmMYB94 are also involved in the activation of cuticular wax biosynthesis, suggesting deep conservation of regulatory processes related to cuticular wax deposition between monocots and dicots.


Assuntos
Proteínas de Plantas/genética , Fatores de Transcrição/genética , Zea mays/genética , Cotilédone/genética , Cotilédone/crescimento & desenvolvimento , Cotilédone/metabolismo , Mutação , Organogênese Vegetal , Proteínas de Plantas/metabolismo , Brotos de Planta/genética , Brotos de Planta/crescimento & desenvolvimento , Brotos de Planta/metabolismo , Plântula/genética , Plântula/crescimento & desenvolvimento , Plântula/metabolismo , Sementes/genética , Sementes/crescimento & desenvolvimento , Sementes/metabolismo , Fatores de Transcrição/metabolismo , Zea mays/embriologia , Zea mays/metabolismo
6.
Physiol Plant ; 153(4): 654-67, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25186023

RESUMO

Antarctic algae play a fundamental role in polar ecosystem thanks to their ability to grow in an extreme environment characterized by low temperatures and variable illumination. Here, for prolonged periods, irradiation is extremely low and algae must be able to harvest light as efficiently as possible. On the other side, at low temperatures even dim irradiances can saturate photosynthesis and drive to the formation of reactive oxygen species. Colonization of this extreme environment necessarily required the optimization of photosynthesis regulation mechanisms by algal organisms. In order to investigate these adaptations we analyzed the time course of physiological and morphological responses to different irradiances in Koliella antarctica, a green microalga isolated from Ross Sea (Antarctica). Koliella antarctica not only modulates cell morphology and composition of its photosynthetic apparatus on a long-term acclimation, but also shows the ability of a very fast response to light fluctuations. Koliella antarctica controls the activity of two xanthophyll cycles. The first, involving lutein epoxide and lutein, may be important for the growth under very low irradiances. The second, involving conversion of violaxanthin to antheraxanthin and zeaxanthin, is relevant to induce a fast and particularly strong non-photochemical quenching, when the alga is exposed to higher light intensities. Globally K. antarctica thus shows the ability to activate a palette of responses of the photosynthetic apparatus optimized for survival in its natural extreme environment.


Assuntos
Aclimatação/efeitos da radiação , Fotossíntese/efeitos da radiação , Estreptófitas/efeitos da radiação , Adaptação Fisiológica , Temperatura Baixa , Meio Ambiente , Luz , Luteína/metabolismo , Estreptófitas/fisiologia , Estreptófitas/ultraestrutura , Xantofilas/metabolismo , Zeaxantinas/metabolismo
7.
J Phycol ; 51(6): 1172-88, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26987011

RESUMO

The family Scenedesmaceae is a taxonomically complicated group due to its simple morphology, high phenotypic plasticity, and the presence of cryptic taxa. Over the years several taxonomic revisions, based on molecular data, affected the family. Here, we describe a new scenedesmacean species from Antarctica, Chodatodesmus australis, based on phylogenetic analyses of data from nuclear (ITS2 spacer, 18S rDNA), and plastid (rbcL, tufA) markers. Morphological (LM and SEM) and ultrastructural (TEM) observations, carried out both on the holotype of C. australis and on the generitype of Chodatodesmus, allow us to emend the original generic description of this genus. Our molecular and phylogenetic data also reveal the existence of a new monotypic genus, Flechtneria, inside the family Scenedesmaceae and lead to the taxonomic reassignment of some microalgal strains available in International Culture Collections to new taxa. Of the considered genomic regions, the tufA gene was the easiest to amplify and sequence and it showed the highest phylogenetic signal, even if the number of sequences already available for this marker in the public databases was considerably lower than for the other chosen loci. The rbcL gene also provided good phylogenetic signal, but its amplification and sequencing were generally more problematic. The nuclear markers gave lower phylogenetic signals, but the 18S rDNA allowed distinction at the genus level and the ITS2 spacer had the advantage that secondary structures could be considered in the analyses. The use of more than one molecular locus is suggested to obtain reliable results in the characterization of scenedesmacean strains.

8.
Proc Natl Acad Sci U S A ; 109(27): 11043-8, 2012 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-22711813

RESUMO

A potassium channel (SynK) of the cyanobacterium Synechocystis sp. PCC 6803, a photoheterotrophic model organism for the study of photosynthesis, has been recently identified and demonstrated to function as a potassium selective channel when expressed in a heterologous system and to be located predominantly to the thylakoid membrane in cyanobacteria. To study its physiological role, a SynK-less knockout mutant was generated and characterized. Fluorimetric experiments indicated that SynK-less cyanobacteria cannot build up a proton gradient as efficiently as WT organisms, suggesting that SynK might be involved in the regulation of the electric component of the proton motive force. Accordingly, measurements of flash-induced cytochrome b(6)f turnover and respiration pointed to a reduced generation of ΔpH and to an altered linear electron transport in mutant cells. The lack of the channel did not cause an altered membrane organization, but decreased growth and modified the photosystem II/photosystem I ratio at high light intensities because of enhanced photosensitivity. These data shed light on the function of a prokaryotic potassium channel and reports evidence, by means of a genetic approach, on the requirement of a thylakoid ion channel for optimal photosynthesis.


Assuntos
Proteínas de Bactérias/fisiologia , Fotossíntese/fisiologia , Canais de Potássio/fisiologia , Synechocystis/fisiologia , Tilacoides/fisiologia , Proteínas de Bactérias/genética , Clorofila/metabolismo , Transporte de Elétrons , Técnicas de Inativação de Genes , Potenciais da Membrana/fisiologia , Oxigênio/metabolismo , Complexo de Proteínas do Centro de Reação Fotossintética/genética , Complexo de Proteínas do Centro de Reação Fotossintética/fisiologia , Complexo de Proteína do Fotossistema I/fisiologia , Complexo de Proteína do Fotossistema II/fisiologia , Canais de Potássio/genética , Prótons , Synechocystis/genética
9.
Eukaryot Cell ; 12(5): 665-76, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23457191

RESUMO

Microalgae of the genus Nannochloropsis are capable of accumulating triacylglycerols (TAGs) when exposed to nutrient limitation (in particular, nitrogen [N]) and are therefore considered promising organisms for biodiesel production. Here, after nitrogen removal from the medium, Nannochloropsis gaditana cells showed extensive triacylglycerol accumulation (38% TAG on a dry weight basis). Triacylglycerols accumulated during N deprivation harbored signatures, indicating that they mainly stemmed from freshly synthesized fatty acids, with a small proportion originating from a recycling of membrane glycerolipids. The amount of chloroplast galactoglycerolipids, which are essential for the integrity of thylakoids, decreased, while their fatty acid composition appeared to be unaltered. In starved cells, galactolipids were kept at a level sufficient to maintain chloroplast integrity, as confirmed by electron microscopy. Consistently, N-starved Nannochloropsis cells contained less photosynthetic membranes but were still efficiently performing photosynthesis. N starvation led to a modification of the photosynthetic apparatus with a change in pigment composition and a decrease in the content of all the major electron flow complexes, including photosystem II, photosystem I, and the cytochrome b(6)f complex. The photosystem II content was particularly affected, leading to the inhibition of linear electron flow from water to CO(2). Such a reduction, however, was partially compensated for by activation of alternative electron pathways, such as cyclic electron transport. Overall, these changes allowed cells to modify their energetic metabolism in order to maintain photosynthetic growth.


Assuntos
Cloroplastos/metabolismo , Galactolipídeos/metabolismo , Nitrogênio/metabolismo , Complexo de Proteína do Fotossistema II/metabolismo , Estramenópilas/metabolismo , Triglicerídeos/biossíntese , Carotenoides/metabolismo , Clorofila/metabolismo , Cloroplastos/ultraestrutura , Ácidos Graxos/metabolismo , Metabolismo dos Lipídeos , Microalgas/metabolismo , Microalgas/ultraestrutura , Oxirredução , Fotossíntese , Estramenópilas/ultraestrutura
10.
Plant Physiol Biochem ; 213: 108793, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38870681

RESUMO

Recently, cyanobacteria have gained attention in space exploration to support long-term crewed missions via Bioregenerative Life Support Systems. In this frame, cyanobacteria would provide biomass and profitable biomolecules through oxygenic photosynthesis, uptaking CO2, and releasing breathable O2. Their growth potential and organic matter production will depend on their ability to photoacclimate to different light intensities and spectra, maximizing incident light harvesting. Studying cyanobacteria responses to different light regimes will also benefit the broader field of astrobiology, providing data on the possibility of oxygenic photosynthetic life on planets orbiting stars with emission spectra different than the Sun. Here, we tested the acclimation and productivity of Synechococcus sp. PCC7335 (hereafter PCC7335), capable of Far-Red Light Photoacclimation (FaRLiP) and type III chromatic acclimation (CA3), in an anoxic, CO2-enriched atmosphere and under a spectrum simulating the low energetic light regime of an M-dwarf star, also comparable to a subsuperficial environment. When exposed to the light spectrum, with few photons in the visible (VIS) and rich in far-red (FR), PCC7335 did not activate FaRLiP but acclimated only via CA3, achieving a biomass productivity higher than expected, considering the low VIS light availability, and a higher production of phycocyanin, a valuable pigment, with respect to solar light. Its growth or physiological responses of PCC7335 were not affected by the anoxic atmosphere. In these conditions, PCC7335 efficiently produced O2 and scavenged CO2. Results highlight the photosynthetic plasticity of PCC7335, its suitability for astrobiotechnological applications, and the importance to investigate biodiversity of oxygenic photosynthesis for searching life beyond Earth.


Assuntos
Fotossíntese , Synechococcus , Synechococcus/metabolismo , Synechococcus/efeitos da radiação , Synechococcus/crescimento & desenvolvimento , Atmosfera/química , Exobiologia , Luz , Dióxido de Carbono/metabolismo , Aclimatação , Oxigênio/metabolismo
11.
Animals (Basel) ; 13(8)2023 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-37106838

RESUMO

The nutraceutical supplementation of Spirulina (Arthrospira platensis) in dogs and cats has not yet been investigated. The aim of this study was to evaluate if the dietary supplementation of increasing amounts of Spirulina for 6 weeks is palatable to pets and to assess the owner's perception of such supplementation. The owners of the 60 dogs and 30 cats that participated in this study were instructed to daily provide Spirulina tablets starting with a daily amount of 0.4 g, 0.8 g, and 1.2 g for cats as well as small dogs, medium dogs, and large dogs, respectively, and allowing a dose escalation of 2× and 3× every 2 weeks. The daily amount (g/kg BW) of Spirulina ranged from 0.08 to 0.25 for cats, from 0.06 to 0.19 for small-sized dogs, from 0.05 to 0.15 for medium-sized dogs, and from 0.04 to 0.12 for large-sized dogs. Each owner completed a questionnaire at the time of recruitment and the end of each 2-week period. No significant effect on the fecal score, defecation frequency, vomiting, scratching, lacrimation, general health status, and behavioral attitudes was detected by the owners' reported evaluations. Most animals accepted Spirulina tablets either administrated alone or mixed with food in the bowl. Daily supplementation of Spirulina for 6 weeks in the amounts provided in this study is therefore palatable and well tolerated by dogs and cats.

12.
Life (Basel) ; 13(8)2023 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-37629498

RESUMO

Oxygenic photosynthetic organisms (OPOs) are primary producers on Earth and generate surface and atmospheric biosignatures, making them ideal targets to search for life from remote on Earth-like exoplanets orbiting stars different from the Sun, such as M-dwarfs. These stars emit very low light in the visible and most light in the far-red, an issue for OPOs, which mostly utilize visible light to photosynthesize and grow. After successfully testing procaryotic OPOs (cyanobacteria) under a simulated M-dwarf star spectrum (M7, 365-850 nm) generated through a custom-made lamp, we tested several eukaryotic OPOs: microalgae (Dixoniella giordanoi, Microchloropsis gaditana, Chromera velia, Chlorella vulgaris), a non-vascular plant (Physcomitrium patens), and a vascular plant (Arabidopsis thaliana). We assessed their growth and photosynthetic efficiency under three light conditions: M7, solar (SOL) simulated spectra, and far-red light (FR). Microalgae grew similarly in SOL and M7, while the moss P. patens showed slower growth in M7 with respect to SOL. A. thaliana grew similarly in SOL and M7, showing traits typical of shade-avoidance syndrome. Overall, the synergistic effect of visible and far-red light, also known as the Emerson enhancing effect, could explain the growth in M7 for all organisms. These results lead to reconsidering the possibility and capability of the growth of OPOs and are promising for finding biosignatures on exoplanets orbiting the habitable zone of distant stars.

13.
Tree Physiol ; 43(6): 893-908, 2023 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-36738252

RESUMO

Leaves are the most important photosynthetic organs in most woody plants, but chloroplasts are also found in organs optimized for other functions. However, the actual photosynthetic efficiency of these chloroplasts is still unclear. We analyzed bark and wood chloroplasts of Fraxinus ornus L. saplings. Optical and spectroscopic methods were applied to stem samples and compared with leaves. A sharp light gradient was detected along the stem radial direction, with blue light mainly absorbed by the outer bark, and far-red-enriched light reaching the underlying xylem and pith. Chlorophylls were evident in the xylem rays and the pith and showed an increasing concentration gradient toward the bark. The stem photosynthetic apparatus showed features typical of acclimation to a low-light environment, such as larger grana stacks, lower chlorophyll a/b and photosystem I/II ratios compared with leaves. Despite likely receiving very few photons, wood chloroplasts were photosynthetically active and fully capable of generating a light-dependent electron transport. Our data provide a comprehensive scenario of the functional features of bark and wood chloroplasts in a woody species and suggest that stem photosynthesis is coherently optimized to the prevailing micro-environmental conditions at the bark and wood level.


Assuntos
Fraxinus , Árvores , Árvores/metabolismo , Madeira/metabolismo , Clorofila A/metabolismo , Secas , Casca de Planta/metabolismo , Cloroplastos/metabolismo , Fotossíntese , Clorofila/metabolismo , Luz , Folhas de Planta/metabolismo , Complexo de Proteína do Fotossistema II
14.
Front Plant Sci ; 14: 1070359, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36824196

RESUMO

Introduction: The search for life on distant exoplanets is expected to rely on atmospheric biosignatures detection, such as oxygen of biological origin. However, it is not demonstrated how much oxygenic photosynthesis, which on Earth depends on visible light, could work under spectral conditions simulating exoplanets orbiting the Habitable Zone of M-dwarf stars, which have low light emission in the visible and high light emission in the far-red/near-infrared. By utilizing cyanobacteria, the first organisms to evolve oxygenic photosynthesis on our planet, and a starlight simulator capable of accurately reproducing the emission spectrum of an M-dwarf in the range 350-900 nm, we could answer this question. Methods: We performed experiments with the cyanobacterium Chlorogloeopsis fritschii PCC6912, capable of Far-Red Light Photoacclimation (FaRLiP), which allows the strain to harvest far-red in addition to visible light for photosynthesis, and Synechocystis sp. PCC6803, a species unable to perform this photoacclimation, comparing their responses when exposed to three simulated light spectra: M-dwarf, solar and far-red. We analysed growth and photosynthetic acclimation features in terms of pigment composition and photosystems organization. Finally, we determined the oxygen production of the strains directly exposed to the different spectra. Results: Both cyanobacteria were shown to grow and photosynthesize similarly under M-dwarf and solar light conditions: Synechocystis sp. by utilizing the few photons in the visible, C. fritschii by harvesting both visible and far-red light, activating the FaRLiP response. Discussion: Our results experimentally show that an M-dwarf light spectrum could support a biological oxygen production similar to that in solar light at the tested light intensities, suggesting the possibility to discover such atmospheric biosignatures on those exoplanets if other boundary conditions are met.

15.
Front Plant Sci ; 14: 1322052, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38304456

RESUMO

Introduction: Cyanobacteria appeared in the anoxic Archean Earth, evolving for the first time oxygenic photosynthesis and deeply changing the atmosphere by introducing oxygen. Starting possibly from UV-protected environments, characterized by low visible and far-red enriched light spectra, cyanobacteria spread everywhere on Earth thanks to their adaptation capabilities in light harvesting. In the last decade, few cyanobacteria species which can acclimate to far-red light through Far-Red Light Photoacclimation (FaRLiP) have been isolated. FaRLiP cyanobacteria were thus proposed as model organisms to study the origin of oxygenic photosynthesis as well as its possible functionality around stars with high far-red emission, the M-dwarfs. These stars are astrobiological targets, as their longevity could sustain life evolution and they demonstrated to host rocky terrestrial-like exoplanets within their Habitable Zone. Methods: We studied the acclimation responses of the FaRLiP strain Chlorogloeopsis fritschii sp. PCC6912 and the non-FaRLiP strain Synechocystis sp. PCC6803 to the combination of three simulated light spectra (M-dwarf, solar and far-red) and two atmospheric compositions (oxic, anoxic). We first checked their growth, O2 production and pigment composition, then we studied their transcriptional responses by RNA sequencing under each combination of light spectrum and atmosphere conditions. Results and discussion: PCC6803 did not show relevant differences in gene expression when comparing the responses to M-dwarf and solar-simulated lights, while far-red caused a variation in the transcriptional level of many genes. PCC6912 showed, on the contrary, different transcriptional responses to each light condition and activated the FaRLiP response under the M-dwarf simulated light. Surprisingly, the anoxic atmosphere did not impact the transcriptional profile of the 2 strains significantly. Results show that both cyanobacteria seem inherently prepared for anoxia and to harvest the photons emitted by a simulated M-dwarf star, whether they are only visible (PCC6803) or also far-red photons (PCC6912). They also show that visible photons in the simulated M-dwarf are sufficient to keep a similar metabolism with respect to solar-simulated light. Conclusion: Results prove the adaptability of the cyanobacterial metabolism and enhance the plausibility of finding oxygenic biospheres on exoplanets orbiting M-dwarf stars.

16.
Cladistics ; 28(4): 357-374, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34872194

RESUMO

Cyanobacteria (phylum Cyanophyta/Cyanobacteria, class Cyanophyceae) are among the most widespread organisms and are able to adapt themselves to different extreme environments. These micro-organisms have an important ecological role, given their ability to perform oxygenic photosynthesis, and are employed in different fields based on their ability to produce several bioactive compounds. Their prokaryotic nature, the presence of many cryptic species, and the coexistence of different nomenclature systems make the taxonomic identification of cyanobacteria particularly difficult. Moreover, for several species, the original reference strains (holotypes) are lacking. Increasingly, authors are using a polyphasic approach to characterize cyanobacteria, while typification is a recent trend that is being used to solve the problem of missing holotypes in other micro-organisms. Here we focus on a filamentous cyanobacterium, isolated from the Euganean Thermal District (Padova, Italy) and temporarily named strain ETS-02, using a polyphasic approach that includes morphological, ultrastructural, biochemical (pigment and fatty acid content), physiological (nitrogen fixation), and genetic (16S rRNA, 16S-23S ITS, cpcB-IGS-cpcA, rpoC1, gyrB, rbcL, nifD loci) analyses. The description of Phormidium cf. irriguum CCALA 759 as the epitype of Phormidium irriguum was also used to complete the characterization of strain ETS-02.

17.
Int J Biol Macromol ; 209(Pt B): 1710-1719, 2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35483514

RESUMO

Therapeutic thermal mud produced by spas of the Euganean Thermal District (Italy) is used as a treatment for arthro-rheumatic diseases. Its production involves the growth of a specific microbiota embedded in a polysaccharidic matrix. Polysaccharides (Microbial-PolySaccharides, M-PS) released in the mud by the resident microorganisms were extracted and analyzed. The monosaccharidic composition analysis showed the presence of galacturonic acid, mannose, xylose, ribose and glucose and a high percentage of sulfated groups in the polymers. To assess their involvement in the therapeutic efficacy of the mud, the M-PS were tested using the model organism zebrafish (Danio rerio). The anti-inflammatory and antioxidant activities were evaluated after confirming the lack of toxic effects during development. Inflammatory state was induced chemically with copper sulfate, or through tail fin amputation procedure and UVB exposure. Recovery from inflammatory condition after exposure to M-PS was always observed with specific morphometric analyses, and further supported by qPCR. Genes linked with the inflammatory and oxidative stress response were investigated confirming the M-PS treatment's efficacy.


Assuntos
Antioxidantes , Peixe-Zebra , Animais , Anti-Inflamatórios/farmacologia , Antioxidantes/farmacologia , Sulfato de Cobre , Estresse Oxidativo , Polissacarídeos/farmacologia , Polissacarídeos/uso terapêutico
18.
Biochim Biophys Acta ; 1793(2): 239-52, 2009 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19000718

RESUMO

The endoplasmic-reticulum chaperone Grp94 is required for the cell surface export of molecules involved in the native immune response, in mesoderm induction and muscle development, but the signals responsible for Grp94 recruitment are still obscure. Here we show for the first time that Grp94 undergoes Tyr-phosphorylation in differentiating myogenic C2C12 cells. By means of phospho-proteomic and immunoprecipitation analyses, and the use of Src-specific inhibitors we demonstrate that the Src-tyrosine-kinase Fyn becomes active early after induction of C2C12 cell differentiation, in parallel with the recruitment and the Tyr-phosphorylation of Grp94, which peaks at 6-hour differentiation. Grp94 is Tyr-phosphorylated inside the endoplasmic reticulum by a lumenal Fyn, as indicated by fluorescence and electronmicroscopy immunolocalization, co-immunoprecipitation after chemical cross-linking and by treatment of intact endoplasmic-reticulum vesicles with proteinase K. Furthermore, fractionation of cellular membrane compartments and double-immunofluorescence studies showed that Tyr-phosphorylation of Grp94 is necessary for the protein translocation from the endoplasmic reticulum to the Golgi apparatus. These results indicate that Fyn-catalyzed Tyr-phosphorylation of Grp94 is an event required to promote the chaperone export from the endoplasmic reticulum occurring in the early phase of myoblast differentiation.


Assuntos
Diferenciação Celular , Retículo Endoplasmático/metabolismo , Complexo de Golgi/metabolismo , Glicoproteínas de Membrana/metabolismo , Mioblastos/citologia , Fosfotirosina/metabolismo , Proteínas Proto-Oncogênicas c-fyn/metabolismo , Animais , Linhagem Celular , Proliferação de Células , Retículo Endoplasmático/ultraestrutura , Complexo de Golgi/ultraestrutura , Camundongos , Mioblastos/enzimologia , Mioblastos/ultraestrutura , Fosforilação , Ligação Proteica , Transporte Proteico , Ratos , Especificidade por Substrato , Quinases da Família src/metabolismo
19.
Biochim Biophys Acta ; 1787(7): 947-54, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-19366603

RESUMO

Human T-cell leukemia virus type-1 (HTLV-1) expresses an 87-amino acid protein named p13 that is targeted to the inner mitochondrial membrane. Previous studies showed that a synthetic peptide spanning an alpha helical domain of p13 alters mitochondrial membrane permeability to cations, resulting in swelling. The present study examined the effects of full-length p13 on isolated, energized mitochondria. Results demonstrated that p13 triggers an inward K(+) current that leads to mitochondrial swelling and confers a crescent-like morphology distinct from that caused by opening of the permeability transition pore. p13 also induces depolarization, with a matching increase in respiratory chain activity, and augments production of reactive oxygen species (ROS). These effects require an intact alpha helical domain and strictly depend on the presence of K(+) in the assay medium. The effects of p13 on ROS are mimicked by the K(+) ionophore valinomycin, while the protonophore FCCP decreases ROS, indicating that depolarization induced by K(+) vs. H(+) currents has different effects on mitochondrial ROS production, possibly because of their opposite effects on matrix pH (alkalinization and acidification, respectively). The downstream consequences of p13-induced mitochondrial K(+) permeability are likely to have an important influence on the redox state and turnover of HTLV-1-infected cells.


Assuntos
Vírus Linfotrópico T Tipo 1 Humano , Mitocôndrias/metabolismo , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Potássio/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Cálcio/farmacologia , Carbonil Cianeto p-Trifluormetoxifenil Hidrazona/farmacologia , Vírus Linfotrópico T Tipo 1 Humano/genética , Vírus Linfotrópico T Tipo 1 Humano/metabolismo , Humanos , Ionóforos/farmacologia , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/ultraestrutura , Poro de Transição de Permeabilidade Mitocondrial , Dilatação Mitocondrial/efeitos dos fármacos , Modelos Biológicos , Permeabilidade , Canais de Potássio/metabolismo , Valinomicina/farmacologia
20.
Front Plant Sci ; 11: 182, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32210991

RESUMO

Oxygenic photosynthetic microorganisms are a focal point of research in the context of human space exploration. As part of the bioregenerative life-support systems, they could have a key role in the production of breathable O2, edible biomasses and in the regeneration of CO2 rich-atmospheres and wastewaters produced by astronauts. The test of the organism's response to simulated physico-chemical parameters of planetary bodies could also provide important information about their habitability potential. It is believed that the success of future planetary and space missions will require innovative technologies, developed on the base of preliminary experiments in custom-made laboratory facilities. In this context, simulation chambers will play a pivotal role by allowing the growth of the microorganisms under controlled conditions and the evaluation in real-time of their biomass productivity and impact on atmosphere composition. We here present a system capable of addressing these requirements with high replicability and low costs. The setup is composed by three main parts: 1) a Star Light Simulator, able to generate different light intensities and spectra, including those of non-solar stars; 2) an Atmosphere Simulator Chamber where cultures of photosynthetic microorganisms can be exposed to different gas compositions; 3) a reflectivity detection system to measure from remote the Normalized Difference Vegetation Indexes (NDVI). Such a setup allows us to monitor photosynthetic microorganism's growth and gas exchange performances under selected conditions of light quality and intensity, temperature, pressure, and atmospheres simulating non-terrestrial environments. All parameters are detected by remote sensing techniques, thus without interfering with the experiments and altering the environmental conditions set. We validated the setup by growing cyanobacteria liquid cultures under different light intensities of solar illumination, collecting data on their growth rate, photosynthetic activity, and gas exchange capacity. We utilized the reflectivity detection system to measure the reflection spectra of the growing cultures, obtaining their relative NDVI that was shown to correlate with optical density, chlorophyll content, and dry weight, demonstrating the potential application of this index as a proxy of growth.

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