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1.
Science ; 369(6499)2020 07 03.
Artigo em Inglês | MEDLINE | ID: mdl-32631870

RESUMO

Microbial communities are essential to fundamental processes on Earth. Underlying the compositions and functions of these communities are nutritional interdependencies among individual species. One class of nutrients, cobamides (the family of enzyme cofactors that includes vitamin B12), is widely used for a variety of microbial metabolic functions, but these structurally diverse cofactors are synthesized by only a subset of bacteria and archaea. Advances at different scales of study-from individual isolates, to synthetic consortia, to complex communities-have led to an improved understanding of cobamide sharing. Here, we discuss how cobamides affect microbes at each of these three scales and how integrating different approaches leads to a more complete understanding of microbial interactions.


Assuntos
Cobamidas/metabolismo , Meio Ambiente , Interações Microbianas , Microbiota , Complexo Vitamínico B/metabolismo , Animais , Archaea/metabolismo , Bactérias/metabolismo , Cobamidas/química , Planeta Terra , Eucariotos/metabolismo , Modelos Biológicos , Complexo Vitamínico B/química
2.
Biosens Bioelectron ; 159: 112214, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32364936

RESUMO

Recent advances in electrochemical biosensors for pathogen detection are reviewed. Electrochemical biosensors for pathogen detection are broadly reviewed in terms of transduction elements, biorecognition elements, electrochemical techniques, and biosensor performance. Transduction elements are discussed in terms of electrode material and form factor. Biorecognition elements for pathogen detection, including antibodies, aptamers, and imprinted polymers, are discussed in terms of availability, production, and immobilization approach. Emerging areas of electrochemical biosensor design are reviewed, including electrode modification and transducer integration. Measurement formats for pathogen detection are classified in terms of sample preparation and secondary binding steps. Applications of electrochemical biosensors for the detection of pathogens in food and water safety, medical diagnostics, environmental monitoring, and bio-threat applications are highlighted. Future directions and challenges of electrochemical biosensors for pathogen detection are discussed, including wearable and conformal biosensors, detection of plant pathogens, multiplexed detection, reusable biosensors for process monitoring applications, and low-cost, disposable biosensors.


Assuntos
Bactérias/isolamento & purificação , Técnicas Biossensoriais/instrumentação , Técnicas Eletroquímicas , Eucariotos/isolamento & purificação , Técnicas Microbiológicas/instrumentação , Vírus/isolamento & purificação , Animais , Betacoronavirus/isolamento & purificação , Infecções por Coronavirus/diagnóstico , Infecções por Coronavirus/virologia , Eletrodos , Humanos , Técnicas Microbiológicas/normas , Técnicas Microbiológicas/tendências , Pandemias , Pneumonia Viral/diagnóstico , Pneumonia Viral/virologia
3.
4.
Parasitol Res ; 119(7): 2005-2023, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32394001

RESUMO

The focus of this review is a group of structures/organelles collectively known as extracellular vesicles (EVs) that are secreted by most, if not all, cells, varying from mammalian cells to protozoa and even bacteria. They vary in size: some are small (100-200 nm) and others are larger (> 200 nm). In protozoa, however, most of them are small or medium in size (200-400 nm). These include vesicles from different origins. We briefly review the biogenesis of this distinct group that includes (a) exosome, which originates from the multivesicular bodies, an important component of the endocytic pathway; (b) ectosome, formed from a budding process that takes place in the plasma membrane of the cells; (c) vesicles released from the cell surface following a process of patching and capping of ligand/receptor complexes; (d) other processes where tubules secreted by the parasite subsequently originate exosome-like structures. Here, special emphasis is given to EVs secreted by parasitic protozoa such as Leishmania, Trypanosoma, Plasmodium, Toxoplasma, Cryptosporidium, Trichomonas, and Giardia. Most of them have been characterized as exosomes that were isolated using several approaches and characterized by electron microscopy, proteomic analysis, and RNA sequencing. The results obtained show clearly that they present several proteins and different types of RNAs. From the functional point of view, it is now clear that the secreted exosomes can be incorporated by the parasite itself as well as by mammalian cells with which they interact. As a consequence, there is interference both with the parasite (induction of differentiation, changes in infectivity, etc.) and with the host cell. Therefore, the EVs constitute a new system of transference of signals among cells. On the other hand, there are suggestions that exosomes may constitute potential biotechnology tools and are important players of what has been designated as nanobiotechnology. They may constitute an important delivery system for gene therapy and molecular-displaying cell regulation capabilities when incorporated into other cells and even by interfering with the exosomal membrane during its biogenesis, targeting the vesicles via specific ligands to different cell types. These vesicles may reach the bloodstream, overflow through intercellular junctions, and even pass through the central nervous system blood barrier. There is evidence that it is possible to interfere with the composition of the exosomes by interfering with multivesicular body biogenesis.


Assuntos
Membrana Celular/metabolismo , Eucariotos/metabolismo , Vesículas Extracelulares/metabolismo , Interações Hospedeiro-Parasita/fisiologia , Proteínas de Protozoários/metabolismo , Animais , Transporte Biológico , Exossomos/metabolismo , Vesículas Extracelulares/fisiologia , Humanos , Microscopia Eletrônica , Proteômica
5.
Biol Res ; 53(1): 24, 2020 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-32471519

RESUMO

BACKGROUND: BMPR-1B is part of the transforming growth factor ß super family and plays a pivotal role in ewe litter size. Functional loss of exon-8 mutations in the BMPR-1B gene (namely the FecB gene) can increase both the ewe ovulation rate and litter size. RESULTS: This study constructed a eukaryotic expression system, prepared a monoclonal antibody, and characterized BMPR-1B/FecB protein-protein interactions (PPIs). Using Co-immunoprecipitation coupled to mass spectrometry (Co-IP/MS), 23 proteins were identified that specifically interact with FecB in ovary extracts of ewes. Bioinformatics analysis of selected PPIs demonstrated that FecB associated with several other BMPs, primarily via signal transduction in the ovary. FecB and its associated interaction proteins enriched the reproduction process via BMP2 and BMP4 pathways. Signal transduction was identified via Smads proteins and TGF-beta signaling pathway by analyzing the biological processes and pathways. Moreover, other target proteins (GDF5, GDF9, RhoD, and HSP 10) that interact with FecB and that are related to ovulation and litter size in ewes were identified. CONCLUSIONS: In summary, this research identified a novel pathway and insight to explore the PPi network of BMPR-1B.


Assuntos
Receptores de Proteínas Morfogenéticas Ósseas Tipo I/genética , Eucariotos/genética , Ovário/metabolismo , Mapas de Interação de Proteínas/genética , Animais , Receptores de Proteínas Morfogenéticas Ósseas Tipo I/metabolismo , Biologia Computacional , Eucariotos/metabolismo , Feminino , Genótipo , Espectrometria de Massas , Mutação , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição , Ovinos , Transdução de Sinais
6.
BMC Bioinformatics ; 21(1): 220, 2020 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-32471343

RESUMO

BACKGROUND: The first step in understanding ecological community diversity and dynamics is quantifying community membership. An increasingly common method for doing so is through metagenomics. Because of the rapidly increasing popularity of this approach, a large number of computational tools and pipelines are available for analysing metagenomic data. However, the majority of these tools have been designed and benchmarked using highly accurate short read data (i.e. Illumina), with few studies benchmarking classification accuracy for long error-prone reads (PacBio or Oxford Nanopore). In addition, few tools have been benchmarked for non-microbial communities. RESULTS: Here we compare simulated long reads from Oxford Nanopore and Pacific Biosciences (PacBio) with high accuracy Illumina read sets to systematically investigate the effects of sequence length and taxon type on classification accuracy for metagenomic data from both microbial and non-microbial communities. We show that very generally, classification accuracy is far lower for non-microbial communities, even at low taxonomic resolution (e.g. family rather than genus). We then show that for two popular taxonomic classifiers, long reads can significantly increase classification accuracy, and this is most pronounced for non-microbial communities. CONCLUSIONS: This work provides insight on the expected accuracy for metagenomic analyses for different taxonomic groups, and establishes the point at which read length becomes more important than error rate for assigning the correct taxon.


Assuntos
Metagenômica/métodos , Simulação por Computador , Eucariotos/genética , Sequenciamento de Nucleotídeos em Larga Escala , Sequenciamento por Nanoporos , Análise de Sequência de DNA
7.
PLoS One ; 15(4): e0232046, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32352996

RESUMO

Advancements in the field of synthetic biology have been possible due to the development of genetic tools that are able to regulate gene expression. However, the current toolbox of gene regulatory tools for eukaryotic systems have been outpaced by those developed for simple, single-celled systems. Here, we engineered a set of gene regulatory tools by combining self-cleaving ribozymes with various upstream competing sequences that were designed to disrupt ribozyme self-cleavage. As a proof-of-concept, we were able to modulate GFP expression in mammalian cells, and then showed the feasibility of these tools in Drosophila embryos. For each system, the fold-reduction of gene expression was influenced by the location of the self-cleaving ribozyme/upstream competing sequence (i.e. 5' vs. 3' untranslated region) and the competing sequence used. Together, this work provides a set of genetic tools that can be used to tune gene expression across various eukaryotic systems.


Assuntos
Engenharia Genética/métodos , RNA Catalítico/fisiologia , Biologia Sintética/métodos , Animais , Drosophila/genética , Eucariotos/genética , Eucariotos/metabolismo , Células Eucarióticas/metabolismo , Expressão Gênica/genética , Expressão Gênica/fisiologia , Regulação da Expressão Gênica/genética , Regulação da Expressão Gênica/fisiologia , Conformação de Ácido Nucleico , Estudo de Prova de Conceito , RNA Catalítico/genética , RNA Mensageiro/metabolismo
8.
Phytochemistry ; 175: 112370, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32289597

RESUMO

Peptidoglycan has been retained in chloroplasts that have evolved from cyanobacteria along some evolutionary tracks, but has seemingly been quickly eliminated during evolution of others. It has been eliminated in Rhodophyta, Chlorophyta, Pteridophyta and Spermatophyta, but has been retained in streptophyte algae, Glaukophyta, and Lycophyta. In this article questions emerging from this are raised, and for some of them answers are suggested.


Assuntos
Clorófitas , Eucariotos , Parede Celular , Cloroplastos , Peptidoglicano , Filogenia
9.
Mar Pollut Bull ; 154: 111102, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32319925

RESUMO

Increased exploitation of resources in sensitive marine ecosystems emphasizes the importance of knowledge regarding ecological impacts. However, current bio-monitoring practices are limited in terms of target-organisms and temporal resolution. Hence, developing new technologies is vital for enhanced ecosystem understanding. In this study, we have applied a prototype version of a phylogenetic microarray to assess the eukaryote community structures of marine sediments from an area with ongoing oil and gas drilling activity. The results were compared with data from both sequencing (metabarcoding) and morphology-based monitoring to evaluate whether microarrays were capable of detecting ecosystem disturbances. A significant correlation between microarray data and chemical pollution indicators, as well as sequencing-based results, was demonstrated, and several potential indicator organisms for pollution-associated parameters were identified, among them a large fraction of microorganisms not covered by traditional morphology-based monitoring. This suggests that microarrays have a potential in future environmental monitoring.


Assuntos
Ecossistema , Eucariotos , Biodiversidade , Monitoramento Ambiental , Sedimentos Geológicos , Filogenia
10.
Nat Microbiol ; 5(5): 655-667, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32341569

RESUMO

The discovery of Asgard archaea, phylogenetically closer to eukaryotes than other archaea, together with improved knowledge of microbial ecology, impose new constraints on emerging models for the origin of the eukaryotic cell (eukaryogenesis). Long-held views are metamorphosing in favour of symbiogenetic models based on metabolic interactions between archaea and bacteria. These include the classical Searcy's and Hydrogen hypothesis, and the more recent Reverse Flow and Entangle-Engulf-Endogenize models. Two decades ago, we put forward the Syntrophy hypothesis for the origin of eukaryotes based on a tripartite metabolic symbiosis involving a methanogenic archaeon (future nucleus), a fermentative myxobacterial-like deltaproteobacterium (future eukaryotic cytoplasm) and a metabolically versatile methanotrophic alphaproteobacterium (future mitochondrion). A refined version later proposed the evolution of the endomembrane and nuclear membrane system by invagination of the deltaproteobacterial membrane. Here, we adapt the Syntrophy hypothesis to contemporary knowledge, shifting from the original hydrogen and methane-transfer-based symbiosis (HM Syntrophy) to a tripartite hydrogen and sulfur-transfer-based model (HS Syntrophy). We propose a sensible ecological scenario for eukaryogenesis in which eukaryotes originated in early Proterozoic microbial mats from the endosymbiosis of a hydrogen-producing Asgard archaeon within a complex sulfate-reducing deltaproteobacterium. Mitochondria evolved from versatile, facultatively aerobic, sulfide-oxidizing and, potentially, anoxygenic photosynthesizing alphaproteobacterial endosymbionts that recycled sulfur in the consortium. The HS Syntrophy hypothesis accounts for (endo)membrane, nucleus and metabolic evolution in a realistic ecological context. We compare and contrast the HS Syntrophy hypothesis to other models of eukaryogenesis, notably in terms of the mode and tempo of eukaryotic trait evolution, and discuss several model predictions and how these can be tested.


Assuntos
Archaea/metabolismo , Evolução Biológica , Eucariotos/metabolismo , Células Eucarióticas/metabolismo , Filogenia , Archaea/genética , Bactérias/genética , Núcleo Celular , Eucariotos/genética , Genoma Arqueal , Hidrogênio/metabolismo , Membranas/metabolismo , Mitocôndrias/metabolismo , Oxirredução , Enxofre/metabolismo , Simbiose/fisiologia
11.
Nat Commun ; 11(1): 1710, 2020 04 06.
Artigo em Inglês | MEDLINE | ID: mdl-32249765

RESUMO

The discovery of eukaryotic giant viruses has transformed our understanding of the limits of viral complexity, but the extent of their encoded metabolic diversity remains unclear. Here we generate 501 metagenome-assembled genomes of Nucleo-Cytoplasmic Large DNA Viruses (NCLDV) from environments around the globe, and analyze their encoded functional capacity. We report a remarkable diversity of metabolic genes in widespread giant viruses, including many involved in nutrient uptake, light harvesting, and nitrogen metabolism. Surprisingly, numerous NCLDV encode the components of glycolysis and the TCA cycle, suggesting that they can re-program fundamental aspects of their host's central carbon metabolism. Our phylogenetic analysis of NCLDV metabolic genes and their cellular homologs reveals distinct clustering of viral sequences into divergent clades, indicating that these genes are virus-specific and were acquired in the distant past. Overall our findings reveal that giant viruses encode complex metabolic capabilities with evolutionary histories largely independent of cellular life, strongly implicating them as important drivers of global biogeochemical cycles.


Assuntos
Carbono/metabolismo , Genoma Viral , Vírus Gigantes/genética , Asfarviridae/genética , Ciclo do Ácido Cítrico/genética , Citoplasma/virologia , Eucariotos/virologia , Evolução Molecular , Vírus Gigantes/enzimologia , Vírus Gigantes/metabolismo , Glicólise/genética , Família Multigênica , Nitrogênio/metabolismo , Processos Fototróficos/genética , Processos Fototróficos/efeitos da radiação , Filogenia , Poxviridae/genética
12.
Chemosphere ; 254: 126810, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32334259

RESUMO

Anaerobic membrane bioreactor (AnMBR) is used for the treatment of organic solid waste. Clogging of filtration membrane pores, called membrane fouling, is one of the most serious issues for the sustainable operation of AnMBR. Although the physical and chemical mechanisms of the membrane fouling have been widely studied, the biological mechanisms are still unclear. The biofilm formation and development on the membrane might cause the membrane fouling. In this study, the prokaryotic and eukaryotic microbiomes of the membrane-attached biofilms in an AnMBR treating a model slurry of organic solid waste were investigated by non-destructive microscopy and high-throughput sequencing of 16S and 18S rRNA genes. The non-destructive visualization indicated that the biofilm was layered with different structures. The lowermost residual fouling layer was mesh-like and composed of filamentous microorganisms, while the upper cake layer was mainly the non-dense and non-cell region. The principal coordinate and phylogenetic analyses of the sequence data showed that the biofilm microbiomes were different from the sludge. The lowermost layer consisted of operational taxonomic units that were related to Leptolinea tardivitalis and Methanosaeta concilii (9.53-10.07% and 1.14-1.64% of the total prokaryotes, respectively) and Geotrichum candidum (30.22-82.31% of the total eukaryotes), all of which exhibited the filamentous morphology. Moreover, the upper layer was inhabited by the presumably cake-degrading bacteria and predatory eukaryotes. The biofilm microbiome features were consistent with the microscope-visualized structure. These results demonstrated that the biofilm structure and microbiome were the layer specific, which provides better understanding of biological mechanisms of membrane fouling in the AnMBR.


Assuntos
Reatores Biológicos/microbiologia , Eliminação de Resíduos Líquidos/métodos , Anaerobiose , Bactérias , Biofilmes/crescimento & desenvolvimento , Eucariotos , Sequenciamento de Nucleotídeos em Larga Escala , Membranas , Membranas Artificiais , Microbiota , Microscopia , Filogenia , Células Procarióticas , Esgotos , Resíduos Sólidos
13.
Sci Total Environ ; 719: 137463, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-32112950

RESUMO

Since the capacity of river biofilms to degrade glyphosate has been proven to increase when the availability of dissolved phosphorus (P) in water decreases, the present study investigates the diversity responses of bacterial and eukaryotic microbial communities from biofilms in a search for glyphosate-degrader candidates. Glyphosate and P interactions were observed for eukaryotic communities, the highest community richness and diversity being preserved at low concentrations of glyphosate and P. This trend marked by glyphosate was also observed in the structure of eukaryotic communities. Therefore, phosphorus and glyphosate had a synergistic effect in decreasing the richness and diversity of eukaryotes species in biofilms. However, species richness and diversity in bacterial communities were not affected by glyphosate, though shifts in the structure of these communities were concomitant with the degradation of the herbicide. Bacterial communities capable of using glyphosate as P source were characterized by increases in the relative abundance of certain Bacteroidetes, Chloroflexi, Cyanobacteria, Planctomycetes and alpha-Proteobacteria members. Glyphosate-degrader candidates found in natural river biofilms can be further isolated for better understanding of glyphosate degradation pathways, and used as bioremediation strategies in heavily contaminated sites.


Assuntos
Eucariotos , Rios , Biofilmes , Glicina/análogos & derivados , Fósforo
14.
PLoS Genet ; 16(3): e1008584, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32176685

RESUMO

Progression through the cell cycle in eukaryotes is regulated on multiple levels. The main driver of the cell cycle progression is the periodic activity of cyclin-dependent kinase (CDK) complexes. In parallel, transcription during the cell cycle is regulated by a transcriptional program that ensures the just-in-time gene expression. Many core cell cycle regulators are widely conserved in eukaryotes, among them cyclins and CDKs; however, periodic transcriptional programs are divergent between distantly related species. In addition, many otherwise conserved cell cycle regulators have been lost and independently evolved in yeast, a widely used model organism for cell cycle research. For a better understanding of the evolution of the cell cycle regulation in opisthokonts, we investigated the transcriptional program during the cell cycle of the filasterean Capsaspora owczarzaki, a unicellular species closely related to animals. We developed a protocol for cell cycle synchronization in Capsaspora cultures and assessed gene expression over time across the entire cell cycle. We identified a set of 801 periodic genes that grouped into five clusters of expression over time. Comparison with datasets from other eukaryotes revealed that the periodic transcriptional program of Capsaspora is most similar to that of animal cells. We found that orthologues of cyclin A, B and E are expressed at the same cell cycle stages as in human cells and in the same temporal order. However, in contrast to human cells where these cyclins interact with multiple CDKs, Capsaspora cyclins likely interact with a single ancestral CDK1-3. Thus, the Capsaspora cyclin-CDK system could represent an intermediate state in the evolution of animal-like cyclin-CDK regulation. Overall, our results demonstrate that Capsaspora could be a useful unicellular model system for animal cell cycle regulation.


Assuntos
Ciclo Celular/genética , Quinases Ciclina-Dependentes/genética , Eucariotos/genética , Transcriptoma/genética , Células Cultivadas , Ciclinas/genética , Expressão Gênica/genética , Saccharomyces cerevisiae/genética , Transcrição Genética/genética
15.
Ann Parasitol ; 66(1): 3-12, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32198990

RESUMO

Parasites are transferred between domestic and wild animals, when host animals come in contact with each other, particularly while grazing the same pastures, or when using same water bodies for drinking. Chances of parasite transmission and adaptation are high when hosts are genetically related. Afghan urial (Ovis vignei blanfordi), Suleiman markhor (Capra falconeri jerdoni) and Chiltan wild goat (C. aegagrus chialtanensis) are wild kin of domestic sheep and goats, sharing numerous parasitic diseases with each other. The present study was conducted in 2014­2015, to determine parasitic infections of Suleiman markhor and Afghan urial of Torghar Game Reserve, and the endemic wild goat of Chiltan National Park. For comparison, parasites of domestic small ruminants of these areas were also studied. A total of 11 species of helminth and 20 species of protozoa were recorded. Highly prevalent helminth among wild ruminants were Trichuris spp., Nematodirus spp., Protostrongylus rufescens and Moniezia benedeni, while highly prevalent Eimeria were E. arloingi and E. ninakohlyakimovae in caprines and E. ovinoidalis in urial. Chiltan wild goats were also found infected with Entamoeba spp. A short tabulated review of the helminth and protozoan parasites of wild sheep and goats of Pakistan, India, Iran and Turkey has been presented.


Assuntos
Doenças das Cabras , Cabras/parasitologia , Helmintíase Animal , Parasitos , Infecções Protozoárias em Animais , Animais , Eucariotos/classificação , Eucariotos/isolamento & purificação , Doenças das Cabras/parasitologia , Helmintíase Animal/parasitologia , Helmintos/classificação , Helmintos/isolamento & purificação , Índia , Irã (Geográfico) , Paquistão , Parasitos/classificação , Parasitos/isolamento & purificação , Infecções Protozoárias em Animais/parasitologia
16.
Nat Commun ; 11(1): 1591, 2020 03 27.
Artigo em Inglês | MEDLINE | ID: mdl-32221299

RESUMO

Replicative DNA polymerases (DNAPs) have evolved the ability to copy the genome with high processivity and fidelity. In Eukarya and Archaea, the processivity of replicative DNAPs is greatly enhanced by its binding to the proliferative cell nuclear antigen (PCNA) that encircles the DNA. We determined the cryo-EM structure of the DNA-bound PolD-PCNA complex from Pyrococcus abyssi at 3.77 Å. Using an integrative structural biology approach - combining cryo-EM, X-ray crystallography, protein-protein interaction measurements, and activity assays - we describe the molecular basis for the interaction and cooperativity between a replicative DNAP and PCNA. PolD recruits PCNA via a complex mechanism, which requires two different PIP-boxes. We infer that the second PIP-box, which is shared with the eukaryotic Polα replicative DNAP, plays a dual role in binding either PCNA or primase, and could be a master switch between an initiation and a processive phase during replication.


Assuntos
DNA Polimerase Dirigida por DNA/química , DNA Polimerase Dirigida por DNA/metabolismo , Antígeno Nuclear de Célula em Proliferação/química , Antígeno Nuclear de Célula em Proliferação/metabolismo , Archaea , Proteínas Arqueais/química , Proteínas Arqueais/metabolismo , Clonagem Molecular , Microscopia Crioeletrônica , Cristalografia por Raios X , DNA/metabolismo , Proteínas de Ligação a DNA/química , DNA Polimerase Dirigida por DNA/genética , Eucariotos , Modelos Moleculares , Ligação Proteica , Conformação Proteica , Domínios e Motivos de Interação entre Proteínas , Pyrococcus abyssi/genética , Pyrococcus abyssi/metabolismo , Proteínas Recombinantes de Fusão
17.
Cytogenet Genome Res ; 160(3): 111-117, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32146465

RESUMO

B chromosomes (Bs) are enigmatic accessory genomic elements extensively characterized in diverse eukaryotes. Since their discovery in the beginning of the 20th century, B chromosomes have been the subject of investigation in laboratories all around the world. As a consequence, scientific meetings have dealt with B chromosomes, including the most specific and important conference in the field, "The B Chromosome Conference." The 4th B Chromosome Conference (4BCC) took place in Botucatu, Brazil, in 2019 and was an excellent opportunity to discuss the latest developments in the B chromosome research field. B chromosome science has advanced from classical and molecular cytogenetics to genomics and bioinformatics approaches. The recent advances in next-generation sequencing technologies and high-throughput molecular biology protocols have led Bs to be the subject of massive data analysis, thus enabling the investigation of structural and functional issues not considered before. Although extensive progress has been made, questions are still remaining to be answered. The advances in functional studies based on RNA, epigenetics, and gene ontologies open the perspective to a better understanding of the complex biology of B chromosomes.


Assuntos
Cromossomos/genética , Citogenética , Eucariotos/genética , Evolução Molecular , Brasil , Epigenômica , Genômica , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , RNA/genética
18.
Nat Commun ; 11(1): 1362, 2020 03 13.
Artigo em Inglês | MEDLINE | ID: mdl-32170101

RESUMO

Horizontal transfer of transposable elements (HTT) is an important process shaping eukaryote genomes, yet very few studies have quantified this phenomenon on a large scale or have evaluated the selective constraints acting on transposable elements (TEs) during vertical and horizontal transmission. Here we screen 307 vertebrate genomes and infer a minimum of 975 independent HTT events between lineages that diverged more than 120 million years ago. HTT distribution greatly differs from null expectations, with 93.7% of these transfers involving ray-finned fishes and less than 3% involving mammals and birds. HTT incurs purifying selection (conserved protein evolution) on all TEs, confirming that producing functional transposition proteins is required for a TE to invade new genomes. In the absence of HTT, DNA transposons appear to evolve neutrally within genomes, unlike most retrotransposons, which evolve under purifying selection. This selection regime indicates that proteins of most retrotransposon families tend to process their own encoding RNA (cis-preference), which helps retrotransposons to persist within host lineages over long time periods.


Assuntos
Elementos de DNA Transponíveis , Evolução Molecular , Transferência Genética Horizontal , Vertebrados/genética , Animais , Biologia Computacional , Eucariotos/genética , Genoma , Mamíferos/genética , Taxa de Mutação , Retroelementos
19.
Sheng Wu Gong Cheng Xue Bao ; 36(1): 122-132, 2020 Jan 25.
Artigo em Chinês | MEDLINE | ID: mdl-32072787

RESUMO

Signaling lymphocyte activation family 7 (SLAMF7/CS1) is a cell surface glycoprotein that is highly expressed in multiple myeloma cells. CS1 is a sensitive and specific biomarker for multiple myeloma. CAR-T cell immunotherapy is a new method for the treatment of multiple myeloma. CS1 CAR-T cell immunotherapy has good effect on relapsed refractory multiple myeloma. To detect the expression efficiency of CS1 CAR on CS1 CAR-T cells and to find an auxiliary means to CAR-T cell immunotherapy, we prepared a CS1-Fc fusion protein. First, the extracellular domain of CS1 was amplified from the existing plasmid by PCR and ligated with human IgG1-Fc fragment by overlap extension PCR. The recombinant fragment was ligated into pMH3 eukaryotic expression vector. After restriction enzyme digestion and DNA sequencing, the pMH3-CS1-Fc-his recombinant plasmid was successfully constructed. The recombinant plasmid was transfected into Chinese hamster ovary cell (CHO-S) by liposome. The expression of the CS1-Fc fusion protein in CHO-S cells was identified by flow cytometry after G418 pressure screening. Next, the CS1-Fc fusion protein was purified by nickel column. Western-blot analysis showed that molecular weight of the fusion protein was about 70 kDa was identified by Western blotting. The CS1-Fc fusion protein couldeffectively detect the expression rate of CS1 CAR and promote the activation, proliferation andcytokines secretion of the CS1 CAR-T cells. The results will lay the experimental foundation for the in vitro detection and potentiation of CAR-T cells in multiple myeloma treated with CS1 CAR-T cell.


Assuntos
Eucariotos , Mieloma Múltiplo , Animais , Células CHO , Cricetinae , Cricetulus , Humanos , Proteínas Recombinantes de Fusão , Proteínas Recombinantes
20.
Eur J Protistol ; 73: 125686, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32109646

RESUMO

The life cycle of the centrohelid heliozoan Raphidiophrys heterophryoidea Zlatogursky, 2012 was studied with light and electron microscopy in clonal cultures from the type locality. The alternation of two types of trophozoites, having contrastingly different morphology, was observed. Type 1 trophozoites morphology matched the original description. Type 2 trophozoites tended to form colonies usually of 6-8 individuals, connected with cytoplasmic bridges and their cell size was noticeably bigger, namely 43-45 µm compared to 24.5 µm on average in type 1 trophozoites. Some colonies were forming stalks composed of three or four axopodia covered with scales. Spicules were lacking completely, while plate-scales differed from those of type 1 trophozoites: they had oblong-elliptical shape, larger (5.9-14.1 × 2.4-5.8 µm) size, non-branching septa always reaching scale centre, solid upper plate. The conspecificity of the two trophozoite types was confirmed with the comparison of SSU rDNA gene sequence data. Both types of trophozoites were capable of encystment and excysted individuals always were type 1 trophozoites. A new type of cyst-scales (cup-scales) was described. Transitions between cysts and the two trophozoites types were documented. The diagnosis of R. heterophryoidea was improved accordingly. The possible functions, driving forces, and taxonomic consequences of the polymorphism were discussed.


Assuntos
Eucariotos/classificação , Eucariotos/crescimento & desenvolvimento , Estágios do Ciclo de Vida , Eucariotos/genética , Eucariotos/ultraestrutura , Encistamento de Parasitas/fisiologia , RNA Ribossômico 18S/genética , Especificidade da Espécie , Trofozoítos/fisiologia
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