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1.
Molecules ; 25(18)2020 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-32899754

RESUMO

The emergence of the Coronavirus Disease 2019 (COVID-19) caused by the SARS-CoV-2 virus has led to an unprecedented pandemic, which demands urgent development of antiviral drugs and antibodies; as well as prophylactic approaches, namely vaccines. Algae biotechnology has much to offer in this scenario given the diversity of such organisms, which are a valuable source of antiviral and anti-inflammatory compounds that can also be used to produce vaccines and antibodies. Antivirals with possible activity against SARS-CoV-2 are summarized, based on previously reported activity against Coronaviruses or other enveloped or respiratory viruses. Moreover, the potential of algae-derived anti-inflammatory compounds to treat severe cases of COVID-19 is contemplated. The scenario of producing biopharmaceuticals in recombinant algae is presented and the cases of algae-made vaccines targeting viral diseases is highlighted as valuable references for the development of anti-SARS-CoV-2 vaccines. Successful cases in the production of functional antibodies are described. Perspectives on how specific algae species and genetic engineering techniques can be applied for the production of anti-viral compounds antibodies and vaccines against SARS-CoV-2 are provided.


Assuntos
Antivirais/farmacologia , Produtos Biológicos/farmacologia , Chlamydomonas reinhardtii/genética , Infecções por Coronavirus/tratamento farmacológico , Lectinas/farmacologia , Pneumonia Viral/tratamento farmacológico , Polifenóis/farmacologia , Polissacarídeos/farmacologia , Antivirais/química , Antivirais/isolamento & purificação , Betacoronavirus/efeitos dos fármacos , Betacoronavirus/patogenicidade , Produtos Biológicos/química , Produtos Biológicos/isolamento & purificação , Núcleo Celular/química , Núcleo Celular/genética , Núcleo Celular/metabolismo , Chlamydomonas reinhardtii/química , Chlamydomonas reinhardtii/metabolismo , Cloroplastos/química , Cloroplastos/genética , Cloroplastos/metabolismo , Infecções por Coronavirus/prevenção & controle , Engenharia Genética/métodos , Humanos , Lectinas/química , Lectinas/isolamento & purificação , Coronavírus da Síndrome Respiratória do Oriente Médio/efeitos dos fármacos , Coronavírus da Síndrome Respiratória do Oriente Médio/patogenicidade , Pandemias , Polifenóis/química , Polifenóis/isolamento & purificação , Polissacarídeos/química , Polissacarídeos/isolamento & purificação , Vírus da SARS/efeitos dos fármacos , Vírus da SARS/patogenicidade , Síndrome Respiratória Aguda Grave/tratamento farmacológico , Vacinas Virais/biossíntese , Vacinas Virais/farmacologia
3.
BMC Evol Biol ; 20(1): 96, 2020 07 31.
Artigo em Inglês | MEDLINE | ID: mdl-32736519

RESUMO

BACKGROUND: Chloroplast genome sequence data is very useful in studying/addressing the phylogeny of plants at various taxonomic ranks. However, there are no empirical observations on the patterns, directions, and mutation rates, which are the key topics in chloroplast genome evolution. In this study, we used Calycanthaceae as a model to investigate the evolutionary patterns, directions and rates of both nucleotide substitutions and structural mutations at different taxonomic ranks. RESULTS: There were 2861 polymorphic nucleotide sites on the five chloroplast genomes, and 98% of polymorphic sites were biallelic. There was a single-nucleotide substitution bias in chloroplast genomes. A â†’ T or T â†’ A (2.84%) and G â†’ C or C â†’ G (3.65%) were found to occur significantly less frequently than the other four transversion mutation types. Synonymous mutations kept balanced pace with nonsynonymous mutations, whereas biased directions appeared between transition and transversion mutations and among transversion mutations. Of the structural mutations, indels and repeats had obvious directions, but microsatellites and inversions were non-directional. Structural mutations increased the single nucleotide mutations rates. The mutation rates per site per year were estimated to be 0.14-0.34 × 10- 9 for nucleotide substitution at different taxonomic ranks, 0.64 × 10- 11 for indels and 1.0 × 10- 11 for repeats. CONCLUSIONS: Our direct counts of chloroplast genome evolution events provide raw data for correctly modeling the evolution of sequence data for phylogenetic inferences.


Assuntos
Calycanthaceae/genética , Evolução Molecular , Genoma de Cloroplastos , Mutação/genética , Nucleotídeos/genética , Polimorfismo de Nucleotídeo Único/genética , Alelos , Sequência de Bases , Cloroplastos/genética , Inversão Cromossômica/genética , Loci Gênicos , Mutação INDEL/genética , Repetições de Microssatélites/genética , Taxa de Mutação , Filogenia , Especificidade da Espécie
4.
Aquat Toxicol ; 226: 105585, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32763644

RESUMO

Although excess ammoniacal-nitrogen (NH4+-N) results in the disturbance of various important biochemical and physiological processes, a detailed study on the effects of NH4+-N stress on the photosynthesis and global changes in protein levels in submerged macrophytes is still lacking. Here, the changes of excess NH4+-N on physiological parameters in Hydrilla verticillata (L.f.) Royle, a submerged macrophyte were investigated, including the contents of photosynthetic pigments, soluble sugars, net photosynthesis and respiration, glutamine synthetase (GS) and glutamate synthase (GOGAT) activities, chloroplast ultrastructure, chloroplast reactive oxygen species (ROS) accumulation and protein levels. Our results showed that the net photosynthetic rate and pigment content reached maximum values when the plants were treated with 1 and 2 mg L-1 NH4+-N, respectively, and decreased at NH4+-N concentrations at 5, 10, 15 and 20 mg L-1. This decrease might be caused by ROS accumulation. Compared that in 0.02 mg L-1 NH4+-N as a control, ROS generation in chloroplasts significantly increased in the presence of more than 2 mg L-1 NH4+-N. Consistently, the damages caused by over-accumulated ROS were observed in chloroplast ultrastructure, showing a loose thylakoid membranes and swollen grana/stroma lamellae. Furthermore, through proteomic analysis, we identified 91 differentially expressed protein spots. Among them, six proteins involved in photosynthesis decreased in abundance in response to excess NH4+-N. Surprisingly, the abundance of all the identified proteins that were involved in nitrogen assimilation and amino acid metabolism tended to increase under excess NH4+-N compared with the control, suggestive of the imbalanced carbon and nitrogen (C-N) metabolisms. In support, activated GS and GOGAT cycle was observed, evidenced by higher activities of GS and GOGAT enzymes. To our knowledge, this work is the first description that excess NH4+-N results in chloroplast ultrastructural damages and the first proteomic evidence to support that excess NH4+-N can lead to a decline in photosynthesis and imbalance of C-N metabolism in submerged macrophytes.


Assuntos
Amônia/toxicidade , Cloroplastos/ultraestrutura , Hydrocharitaceae/efeitos dos fármacos , Nitrogênio/toxicidade , Fotossíntese/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Poluentes Químicos da Água/toxicidade , Amônia/metabolismo , Carbono/metabolismo , Cloroplastos/efeitos dos fármacos , Hydrocharitaceae/metabolismo , Nitrogênio/metabolismo , Proteômica , Poluentes Químicos da Água/metabolismo
5.
Ecotoxicol Environ Saf ; 202: 110955, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32800229

RESUMO

The effects of cadmium (Cd) have been investigated in an aquatic plant Ottelia alismoides grown under low CO2. Under low CO2, no Cd treated O. alismoides operated three carbon dioxide-concentrating mechanisms (CCMs) efficiently, including HCO3- acquisition, C4 and CAM photosynthesis. After 4 days of treatment with 200 µM and 2000 µM Cd, O. alismoides exhibited an elevated Cd accumulation along with the increasing Cd concentration. Both Cd treatments induced appreciable phytotoxicities in O. alismoides. The leaves showed chlorosis symptoms and the anatomy as well as chloroplast ultrastructure were obviously damaged. Significant decreases in the content of pigments, chlorophyll fluorescence (Fv/Fm and Yield of PS II) and carbon isotope ratio (δ13C) were measured in leaf extracts of O. alismoides grown with both concentrations of Cd. In addition, the pH-drift technique showed that both Cd-treated O. alismoides plants could not uptake HCO3-. The maximum and minimum acidity in Cd-exposed O. alismoides were greatly decreased and the diurnal change of acidity was absent in both Cd treated plants. Furthermore, significant decreases in ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), pyruvate phosphate dikinase (PPDK) and phosphoenolpyruvate carboxylase (PEPC) activities were also found at Cd treated O. alismoides plants, indicating the disturbance within C4 cycle. The alterations in the functionality of CCMs in O. alismoides induced by Cd might be related with the inhibition of the enzymes such as carbonic anhydrase (CA) and PEPC involved in inorganic carbon fixation, and the destruction of chloroplasts, as well as the re-allocation of energy and nutrients involved in CCMs and Cd detoxification.


Assuntos
Organismos Aquáticos/efeitos dos fármacos , Cádmio/toxicidade , Dióxido de Carbono/metabolismo , Hydrocharitaceae/efeitos dos fármacos , Fotossíntese/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Organismos Aquáticos/metabolismo , Anidrases Carbônicas/metabolismo , Cloroplastos/metabolismo , Hydrocharitaceae/metabolismo , Ribulose-Bifosfato Carboxilase/metabolismo
6.
Sheng Wu Gong Cheng Xue Bao ; 36(7): 1422-1430, 2020 Jul 25.
Artigo em Chinês | MEDLINE | ID: mdl-32748600

RESUMO

HSP21 gene is a key gene to respond high temperature stress in plant and plays an important role in preventing protein denaturation, protecting cell structure and maintaining normal growth and development. Therefore, cloning HSP21 gene is the basis for revealing the molecular mechanism of resistance to high temperature stress in cassava. To obtain cassava HSP21 homologous gene and analyze the properties of predicted protein, electronic cloning technology was used to assemble and derivate new gene in this study, and bioinformatics analysis method was used to analyze the primary to highest structure, hydrophilicity/hydrophobicity, signal peptide, protein homology and phylogenetic evolution of expressed protein. HSP21 gene was 969 bp, its open reading frame was 705 bp, and the predicted protein contains 234 amino acids. The predicted protein is a non-transmembrane protein that is alkaline and hydrophilic, and is mainly localized in the chloroplast. Through multiple sequence alignment and phylogenetic analysis, it was found that the cassava HSP21 protein has high homology with other plants such as Hevea brasiliensis, Ricinus communis, and Jatropha curcas. The results could provide reference for the study of cloning and transformation of this gene.


Assuntos
Biologia Computacional , Proteínas de Choque Térmico , Manihot , Filogenia , Cloroplastos , Clonagem Molecular , Simulação por Computador , Evolução Molecular , Proteínas de Choque Térmico/genética , Manihot/genética
8.
PLoS One ; 15(7): e0235354, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32609773

RESUMO

The Chinese chestnut (Castanea mollissima Bl.) was introduced into Japan about 100 years ago. Since then, a number of Chinese chestnut cultivars and Japanese-Chinese hybrid cultivars have been selected by farmers and plant breeders, but little information has been available about their origins and genetic relationships. A classification based on simple sequence repeat markers was conducted using 230 cultivars including Japanese chestnut (Castanea crenata Sieb. et Zucc.) cultivars originated in Japan, Japanese-Chinese hybrid cultivars, and Chinese chestnut cultivars originated in both Japan and China. First, a search for synonyms (cultivars with identical genotypes) revealed 23 synonym groups among the Chinese chestnut cultivars, and all but one cultivar from each synonym group was omitted from further analyses. Second, genetic structure analysis showed a clear division between Japanese and Chinese chestnut, and most of the Japanese and Chinese cultivars had a simple genetic structure corresponding to the expected species. On the other hand, most Japanese-Chinese hybrid cultivars had admixed genetic structure. Through a combination of parentage and chloroplast haplotype analyses, 16 of the 18 hybrid cultivars in this study were inferred to have parent-offspring relationships with other cultivars originated in Japan. Finally, Bayesian clustering and chloroplast haplotype analysis showed that the 116 Chinese chestnut cultivars could be divided into two groups: one originated in the Hebei region of China and the other originated in the Jiangsu and Anhui regions of China. The Chinese chestnut cultivars selected in Japan showed various patterns of genetic structure including Hebei origin, Jiangsu or Anhui origin, and admixed. The chestnut cultivar genetic classifications obtained in this study will be useful for both Japanese and Chinese chestnut breeding programs.


Assuntos
Cloroplastos/genética , Fagaceae/classificação , Fagaceae/genética , Repetições de Microssatélites/genética , China , Deriva Genética , Genótipo , Japão , Filogenia , Melhoramento Vegetal
9.
PLoS One ; 15(7): e0235622, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32614898

RESUMO

Volvox sect. Volvox is an interesting group of green algae; it comprises mostly monoicous species, but evidence suggests an evolution towards dioicy. Based on cultured strains originating from Thailand, we describe Volvox longispiniferus, a novel species in Volvox sect. Volvox. This species is distinguished from others in the section by the large number of sperm packets in its monoicous sexual spheroids and by the long spines on its zygote wall. Phylogenetic analyses indicate that V. longispiniferus is distinct from the other species of two monophyletic groups within Volvox sect. Volvox. In addition, the novel species produces more zygotes when different cultures are combined compared with a single culture, suggesting a preference for outcrossing.


Assuntos
Volvox/classificação , Cloroplastos/genética , DNA Ribossômico/classificação , DNA Ribossômico/genética , Complexo de Proteína do Fotossistema II/genética , Filogenia , Ribulose-Bifosfato Carboxilase/classificação , Ribulose-Bifosfato Carboxilase/genética , Tailândia , Volvox/genética
10.
Plant Cell ; 32(8): 2449-2450, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32605916
11.
Postepy Biochem ; 66(2): 134-142, 2020 06 27.
Artigo em Polonês | MEDLINE | ID: mdl-32700507

RESUMO

The light phase of photosynthesis is a key energy process in higher plants. Its purpose is to convert light energy into chemical one stored in ATP and NADPH molecules, which are then used to assimilate CO2 and in numerous metabolic processes. Maintaining optimal photosynthesis performance requires strict regulation of thylakoid membranes organization and rapid response to changing environmental conditions. The main factor affecting photosynthesis is light, which, if applied in excessive amounts, leads to a slowdown in the process. Therefore, plants have developed many protective mechanisms regulating the light reactions of photosynthesis and operating at the level of light energy absorption, electron transport, and the distribution and use of reducing power. These include, among others: (i) non-photochemical energy quenching regulating the amount of excitation energy delivered to the photosystems; (ii) 'state transition' process redistributing excitation energy between photosystems; (iii) redundant electron transport pathways responsible for maintaining redox balance in chloroplasts. All these mechanisms, in combination with antioxidant systems, are designed to maintain the function of the photosynthetic apparatus in adverse growth conditions.


Assuntos
Fotossíntese/efeitos da radiação , Plantas/metabolismo , Plantas/efeitos da radiação , Cloroplastos/metabolismo , Cloroplastos/efeitos da radiação , Transporte de Elétrons/efeitos da radiação , Oxirredução/efeitos da radiação
12.
PLoS Genet ; 16(6): e1008814, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32555650

RESUMO

The circadian clocks in chlorophyte algae have been studied in two model organisms, Chlamydomonas reinhardtii and Ostreococcus tauri. These studies revealed that the chlorophyte clocks include some genes that are homologous to those of the angiosperm circadian clock. However, the genetic network architectures of the chlorophyte clocks are largely unknown, especially in C. reinhardtii. In this study, using C. reinhardtii as a model, we characterized RHYTHM OF CHLOROPLAST (ROC) 75, a clock gene encoding a putative GARP DNA-binding transcription factor similar to the clock proteins LUX ARRHYTHMO (LUX, also called PHYTOCLOCK 1 [PCL1]) and BROTHER OF LUX ARRHYTHMO (BOA, also called NOX) of the angiosperm Arabidopsis thaliana. We observed that ROC75 is a day/subjective day-phase-expressed nuclear-localized protein that associates with some night-phased clock genes and represses their expression. This repression may be essential for the gating of reaccumulation of the other clock-related GARP protein, ROC15, after its light-dependent degradation. The restoration of ROC75 function in an arrhythmic roc75 mutant under constant darkness leads to the resumption of circadian oscillation from the subjective dawn, suggesting that the ROC75 restoration acts as a morning cue for the C. reinhardtii clock. Our study reveals a part of the genetic network of C. reinhardtii clock that could be considerably different from that of A. thaliana.


Assuntos
Chlamydomonas reinhardtii/fisiologia , Relógios Circadianos/genética , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/fisiologia , Fatores de Transcrição/fisiologia , Cloroplastos/fisiologia , Ritmo Circadiano/genética , Redes Reguladoras de Genes/fisiologia , Mutação , Fotoperíodo , Plantas Geneticamente Modificadas
13.
Nat Commun ; 11(1): 3238, 2020 06 26.
Artigo em Inglês | MEDLINE | ID: mdl-32591540

RESUMO

The challenge of monitoring in planta dynamic changes of NADP(H) and NAD(H) redox states at the subcellular level is considered a major obstacle in plant bioenergetics studies. Here, we introduced two circularly permuted yellow fluorescent protein sensors, iNAP and SoNar, into Arabidopsis thaliana to monitor the dynamic changes in NADPH and the NADH/NAD+ ratio. In the light, photosynthesis and photorespiration are linked to the redox states of NAD(P)H and NAD(P) pools in several subcellular compartments connected by the malate-OAA shuttles. We show that the photosynthetic increases in stromal NADPH and NADH/NAD+ ratio, but not ATP, disappear when glycine decarboxylation is inhibited. These observations highlight the complex interplay between chloroplasts and mitochondria during photosynthesis and support the suggestions that, under normal conditions, photorespiration supplies a large amount of NADH to mitochondria, exceeding its NADH-dissipating capacity, and the surplus NADH is exported from the mitochondria to the cytosol through the malate-OAA shuttle.


Assuntos
Arabidopsis/fisiologia , Arabidopsis/efeitos da radiação , Luz , Proteínas Luminescentes/metabolismo , NADP/metabolismo , NAD/metabolismo , Fotossíntese/efeitos da radiação , Respiração Celular/efeitos da radiação , Cloroplastos/metabolismo , Citosol/metabolismo , Transporte de Elétrons/efeitos da radiação , Malatos/metabolismo , Mitocôndrias/metabolismo , Modelos Biológicos , Oxirredução , Peroxissomos/metabolismo , Plântula/metabolismo , Plântula/efeitos da radiação
14.
Nat Commun ; 11(1): 2882, 2020 06 08.
Artigo em Inglês | MEDLINE | ID: mdl-32513940

RESUMO

Complex polyketides are typically associated with microbial metabolism. Here, we report that animals also make complex, microbe-like polyketides. We show there is a widespread branch of fatty acid synthase- (FAS)-like polyketide synthase (PKS) proteins, which sacoglossan animals use to synthesize complex products. The purified sacogolassan protein EcPKS1 uses only methylmalonyl-CoA as a substrate, otherwise unknown in animal lipid metabolism. Sacoglossans are sea slugs, some of which eat algae, digesting the cells but maintaining functional chloroplasts. Here, we provide evidence that polyketides support this unusual photosynthetic partnership. The FAS-like PKS family represents an uncharacterized branch of polyketide and fatty acid metabolism, encoding a large diversity of biomedically relevant animal enzymes and chemicals awaiting discovery. The biochemical characterization of an intact animal polyketide biosynthetic enzyme opens the door to understanding the immense untapped metabolic potential of metazoans.


Assuntos
Fotossíntese , Policetídeos/metabolismo , Acil Coenzima A/metabolismo , Animais , Cloroplastos/metabolismo , Escherichia coli/metabolismo , Ácido Graxo Sintases/química , Ácido Graxo Sintases/metabolismo , Gastrópodes/classificação , NADP/metabolismo , Filogenia , Policetídeo Sintases/química , Policetídeo Sintases/metabolismo , Policetídeos/química , Propionatos/química , Propionatos/metabolismo
15.
Plant Mol Biol ; 104(1-2): 39-53, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32564178

RESUMO

Plants are exposed to various environmental cues that lead to reactive oxygen species (ROS) accumulation. ROS production and detoxification are tightly regulated to maintain balance. Although studies of glucose (Glc) are always accompanied by ROS in animals, the role of Glc in respect of ROS in plants is unclear. We isolated gsm2 (Glc-hypersensitive mutant 2), a mutant with a notably chlorotic-cotyledon phenotype. The chloroplast-localized GSM2 was characterized as a transaldolase in the pentose phosphate pathway. With 3% Glc treatment, fewer or no thylakoids were observed in gsm2 cotyledon chloroplasts than in wild-type cotyledon chloroplasts, suggesting that GSM2 is required for chloroplast protection under stress. gsm2 also showed evaluated accumulation of ROS with 3% Glc treatment and was more sensitive to exogenous H2O2 than the wild type. Gene expression analysis of the antioxidant enzymes in gsm2 revealed that chloroplast damage to gsm2 cotyledons results from the accumulation of excessive ROS in response to Glc. Moreover, the addition of diphenyleneiodonium chloride or phenylalanine can rescue Glc-induced chlorosis in gsm2 cotyledons. This work suggests that GSM2 functions to maintain ROS balance in response to Glc during early seedling growth and sheds light on the relationship between Glc, the pentose phosphate pathway and ROS.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Homeostase , RNA Helicases/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Transaldolase/metabolismo , Ácido Abscísico/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Clorofila/metabolismo , Cloroplastos/genética , Cloroplastos/metabolismo , Cotilédone/metabolismo , Regulação da Expressão Gênica de Plantas , Germinação , Glucuronidase/metabolismo , Peróxido de Hidrogênio/metabolismo , Via de Pentose Fosfato/genética , Via de Pentose Fosfato/fisiologia , Fenótipo , RNA Helicases/genética , RNA de Plantas/genética , RNA de Plantas/isolamento & purificação , Plântula/genética , Plântula/metabolismo , Transaldolase/genética
16.
Zhongguo Zhong Yao Za Zhi ; 45(7): 1620-1626, 2020 Apr.
Artigo em Chinês | MEDLINE | ID: mdl-32489041

RESUMO

By analyzing the effects of light intensity on the growth, physiological and biochemical characteristics of Chrysanthemum indicum, the light intensity suitable for the growth of Ch. indicum was revealed, which provided a reference for the planting of Ch. indicum. There were five treatment groups of Ch. indicum, which was planted under 100%, 80%, 60%, 40% and 20% all natural light intensity conditions, respectively. In the meantime, these indicators of photosynthetic physiology, such as relative growth, photosynthetic pigment content, photosynthetic parameters, and chlorophyll fluorescence parameters etc. were measured in the peak period of growth of Ch. indicum as well as related indicators of the protective enzyme system, and the ultrastructure of chloroplast was observed with the use of transmission electron microscope technique. In our study, the results showed that the leaves of Ch. indicum occurred yellow phenomenon in different degrees when Ch. indicum was placed at more than 80% of the total natural light intensity condition, the height and stem diameter of plant reached the maximum at 60% of the total natural light intensity. More importantly, the number of branches of Ch. indicum was significantly increased under the total natural light intensity of more than 60%. Both the content of photosynthetic pigment and net photosynthetic rate were negatively correlated with light intensity, while photosynthetic parameters and chlorophyll fluorescence parameters showed a trend of rising first and then decreasing with the decrease of light intensity. The physiological indexes of Ch.indicum including stomatal conductivity, intracellular CO_2 concentration, transpiration rate, water use efficiency and actual photochemical quantum yield of PS Ⅱ had been determined, and the results showed that all of them were at the highest level under 60% total natural light intensity condition. The chloroplast structure of Ch. indicum was not obviously abnormal under 60% and 80% total natural light intensity treatments, but the stroma lamella was broken under 100% total natural light intensity, and not only the number of chloroplast, but also the number and volume of starch grains were decreased significantly under 20% and 40% total natural light intensity. With the decrease of light intensity, the enzymes activities of SOD and CAT decreased, the activity of POD increased in the early stage and decreased in the later stage, and the content of MDA showed a decreasing trend. The analysis of results indicated that the Ch. indicum can grow under 20%-100% total natural light intensity, but the best growth condition was under 60% total natural light intensity.


Assuntos
Chrysanthemum , Clorofila , Cloroplastos , Luz , Fotossíntese , Folhas de Planta
17.
PLoS One ; 15(6): e0227525, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32555586

RESUMO

The fossil record provides an invaluable insight into the temporal origins of extant lineages of organisms. However, establishing the relationships between fossils and extant lineages can be difficult in groups with low rates of morphological change over time. Molecular dating can potentially circumvent this issue by allowing distant fossils to act as calibration points, but rate variation across large evolutionary scales can bias such analyses. In this study, we apply multiple dating methods to genome-wide datasets to infer the origin of extant species of Isoetes, a group of mostly aquatic and semi-aquatic isoetalean lycopsids, which closely resemble fossil forms dating back to the Triassic. Rate variation observed in chloroplast genomes hampers accurate dating, but genome-wide nuclear markers place the origin of extant diversity within this group in the mid-Paleogene, 45-60 million years ago. Our genomic analyses coupled with a careful evaluation of the fossil record indicate that despite resembling forms from the Triassic, extant Isoetes species do not represent the remnants of an ancient and widespread group, but instead have spread around the globe in the relatively recent past.


Assuntos
Variação Genética , Genômica , Filogenia , Traqueófitas/genética , Evolução Biológica , Cloroplastos/genética , Fósseis , Perfilação da Expressão Gênica , Software
18.
Biol Bull ; 238(3): 154-166, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32597715

RESUMO

Sacoglossans, or "sap-sucking" sea slugs, are primarily algivorous, with many taxa exhibiting kleptoplasty, the feeding and retaining of photosynthetically active chloroplasts from algae. The Plakobranchus species complex exhibits some of the longest kleptoplast retention and survival times under starvation conditions, but the contributions of these kleptoplasts to their survival and overall fitness have been widely debated. In this study we assessed the effects of starvation and light on the fitness of Plakobranchus cf. ianthobaptus and its kleptoplasts by placing starved individuals in eight daily average light treatments, ranging from near dark (2 µmol photon m-2 s-1) to ambient light (470 µmol photon m-2 s-1). Slug weight was used as a metric of fitness, and kleptoplast photosynthetic activity was determined via maximum quantum yield (Fv/Fm) by pulse-amplitude modulated fluorometry as a proxy for kleptoplast health. Plakobranchus individuals in near-dark and high light treatments (>160 µmol photon m-2 s-1) experienced significantly greater weight loss than those in low light (65 µmol photon m-2 s-1) and moderate light treatments (95-135 µmol photon m-2 s-1). Additionally, individuals in high light treatments experienced a rapid decline in kleptoplast photosynthetic activity, while all other treatments experienced minimal decline. This relationship between kleptoplast degradation and weight loss suggests an important link between fitness and kleptoplasty. Given the significant negative effects of ambient conditions, regular refreshment and replenishment of kleptoplasts or physiological or behavioral adjustments are likely employed for the benefits of kleptoplasty to be maintained.


Assuntos
Gastrópodes , Animais , Aplysia , Cloroplastos , Ingestão de Alimentos , Luz , Fotossíntese
19.
Science ; 368(6491): 649-654, 2020 05 08.
Artigo em Inglês | MEDLINE | ID: mdl-32381722

RESUMO

Nature integrates complex biosynthetic and energy-converting tasks within compartments such as chloroplasts and mitochondria. Chloroplasts convert light into chemical energy, driving carbon dioxide fixation. We used microfluidics to develop a chloroplast mimic by encapsulating and operating photosynthetic membranes in cell-sized droplets. These droplets can be energized by light to power enzymes or enzyme cascades and analyzed for their catalytic properties in multiplex and real time. We demonstrate how these microdroplets can be programmed and controlled by adjusting internal compositions and by using light as an external trigger. We showcase the capability of our platform by integrating the crotonyl-coenzyme A (CoA)/ethylmalonyl-CoA/hydroxybutyryl-CoA (CETCH) cycle, a synthetic network for carbon dioxide conversion, to create an artificial photosynthetic system that interfaces the natural and the synthetic biological worlds.


Assuntos
Dióxido de Carbono/metabolismo , Cloroplastos/metabolismo , Cloroplastos/efeitos da radiação , Acil Coenzima A , Biocatálise , Biomimética , Ciclo do Carbono , Luz , Fotossíntese/efeitos da radiação , Spinacia oleracea
20.
PLoS One ; 15(4): e0232295, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32353023

RESUMO

In Rubiaceae phylogenetics, the number of markers often proved a limitation with authors failing to provide well-supported trees at tribal and generic levels. A robust phylogeny is a prerequisite to study the evolutionary patterns of traits at different taxonomic levels. Advances in next-generation sequencing technologies have revolutionized biology by providing, at reduced cost, huge amounts of data for an increased number of species. Due to their highly conserved structure, generally recombination-free, and mostly uniparental inheritance, chloroplast DNA sequences have long been used as choice markers for plant phylogeny reconstruction. The main objectives of this study are: 1) to gain insight in chloroplast genome evolution in the Rubiaceae (Ixoroideae) through efficient methodology for de novo assembly of plastid genomes; and, 2) to test the efficiency of mining SNPs in the nuclear genome of Ixoroideae based on the use of a coffee reference genome to produce well-supported nuclear trees. We assembled whole chloroplast genome sequences for 27 species of the Rubiaceae subfamily Ixoroideae using next-generation sequences. Analysis of the plastid genome structure reveals a relatively good conservation of gene content and order. Generally, low variation was observed between taxa in the boundary regions with the exception of the inverted repeat at both the large and short single copy junctions for some taxa. An average of 79% of the SNP determined in the Coffea genus are transferable to Ixoroideae, with variation ranging from 35% to 96%. In general, the plastid and the nuclear genome phylogenies are congruent with each other. They are well-resolved with well-supported branches. Generally, the tribes form well-identified clades but the tribe Sherbournieae is shown to be polyphyletic. The results are discussed relative to the methodology used and the chloroplast genome features in Rubiaceae and compared to previous Rubiaceae phylogenies.


Assuntos
Cloroplastos/genética , DNA de Cloroplastos/genética , Genoma de Cloroplastos/genética , Genoma de Planta/genética , Rubiaceae/genética , Coffea/genética , Evolução Molecular , Genômica/métodos , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Filogenia , Polimorfismo de Nucleotídeo Único/genética , Análise de Sequência de DNA/métodos
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