RESUMO
SARS-CoV-2 has a zoonotic origin and was transmitted to humans via an undetermined intermediate host, leading to infections in humans and other mammals. To enter host cells, the viral spike protein (S-protein) binds to its receptor, ACE2, and is then processed by TMPRSS2. Whilst receptor binding contributes to the viral host range, S-protein:ACE2 complexes from other animals have not been investigated widely. To predict infection risks, we modelled S-protein:ACE2 complexes from 215 vertebrate species, calculated changes in the energy of the complex caused by mutations in each species, relative to human ACE2, and correlated these changes with COVID-19 infection data. We also analysed structural interactions to better understand the key residues contributing to affinity. We predict that mutations are more detrimental in ACE2 than TMPRSS2. Finally, we demonstrate phylogenetically that human SARS-CoV-2 strains have been isolated in animals. Our results suggest that SARS-CoV-2 can infect a broad range of mammals, but few fish, birds or reptiles. Susceptible animals could serve as reservoirs of the virus, necessitating careful ongoing animal management and surveillance.
Assuntos
Peptidil Dipeptidase A/química , Filogenia , Glicoproteína da Espícula de Coronavírus/química , Enzima de Conversão de Angiotensina 2 , Animais , Betacoronavirus/classificação , Betacoronavirus/genética , Humanos , Mamíferos , Simulação de Acoplamento Molecular , Mutação , Peptidil Dipeptidase A/classificação , Peptidil Dipeptidase A/genética , Peptidil Dipeptidase A/metabolismo , Ligação Proteica , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus/metabolismoRESUMO
A novel myb-like gene (Atmyb5) has been isolated from a genomic library of Arabidopsis thaliana. The gene contains a single intron in the region coding for the Myb domains. The Myb domains are highly homologous to other animal and plant Myb proteins. Arabidopsis plants transgenic for a chimeric Atmyb5 promoter/GUS gene expressed the enzyme in a developmentally controlled and tissue specific manner. The GUS activity was detected in developing leaf trichomes, stipules, epidermal cells on the margins of young rosette and cauline leaves, and in immature seeds. Atmyb5 mRNA appears between fertilization and the 16 cell stage of embryo development and persists beyond the heart stage.
Assuntos
Proteínas de Arabidopsis , Arabidopsis/genética , Genes de Plantas , Oncogenes , Proteínas de Plantas/biossíntese , Sequência de Aminoácidos , Animais , Arabidopsis/citologia , Arabidopsis/fisiologia , Sequência de Bases , Sequência Conservada , Primers do DNA , Biblioteca Genômica , Glucuronidase/biossíntese , Dados de Sequência Molecular , Folhas de Planta , Proteínas de Plantas/química , Proteínas de Plantas/genética , Reação em Cadeia da Polimerase , Regiões Promotoras Genéticas , Proteínas Proto-Oncogênicas/química , Proteínas Proto-Oncogênicas c-myb , RNA Mensageiro/análise , RNA Mensageiro/biossíntese , Proteínas Recombinantes de Fusão/biossíntese , Sequências Repetitivas de Ácido Nucleico , Mapeamento por Restrição , Sementes , Homologia de Sequência de Aminoácidos , Transativadores/químicaRESUMO
O suprimento de nutrientes constitui-se em importante fator na nutrição da plantaforrageira, refletindo no aumento de produtividade de massa seca (PMS) e melhoria da qualidade.A correta aplicação de fertilizantes em áreas de pastagens degradadas, ao fornecer nutrientes paraatender as necessidades metabólicas, promove o desenvolvimento das plantas forrageiras, e porconsequência, restabelece a cultura. Objetivou-se com esse trabalho avaliar o efeito de combinaçõesde calagem, adubação e sobressemeadura na recuperação do capim-braquiária (Brachiaria decumbensStapf cv. Basilisk), em estágio avançado de degradação. O delineamento experimental utilizadofoi em blocos casualizados com seis tratamentos e quatro repetições. Os tratamentos avaliadoscorrespondem a testemunha; calagem; calagem + NPK; calagem + NPK + FTE (fritted trace elements);calagem + NPK + Zn; e calagem + NPK + FTE + sobressemeadura de capim-marandu (Brachiariabrizantha cv. Marandu). As combinações de calagem e adubação não influenciaram a composiçãoquímica da pastagem. O tratamento com calagem + NPK + FTE + sobressemeadura foi superior naPMS em relação ao tratamento testemunha, não diferindo dos demais. As concentrações médias deN, P, Ca e Mg da parte aérea do capim-braquiária, não foram influenciadas pelas combinações deadubação. Na avaliação da exportação total de N pelas plantas, houve efeito significativo, sendoo tratamento com calagem + NPK + FTE + sobressemeadura superior (75,76%) aos tratamentostestemunha e calagem, que não diferiram entre si. A utilização de calagem e adubação, em únicaaplicação, não é suficiente para a completa recuperação e aumento da produtividade e qualidadedo capim-braquiária. O uso da sobressemeadura do capim-marandu, sobre pastagens de capimbraquiária,em conjunto com a calagem e a adubação, é uma boa alternativa para o aumento daprodutividade e melhoria na qualidade de pastagens em estado avançado de degradação...
The supply of nutrients is an important factor for pasture nutrition, increasing biomass productivity and improving forage quality. The correct application of fertilizers to degraded pasture areas promotes the development of forage plants and the consequent reestablishment of the culture by providing nutrients to meet the metabolic requirements of the plant. The objective of this study was to evaluate the effect of combinations of liming, fertilization and overseedingon the recovery of Brachiaria grass (Brachiaria decumbens Stapf cv. Basilisk) in an advanced stageof degradation. A randomized block design consisting of six treatments and four repetitions was used. The following treatments were evaluated: control; liming; liming + NPK; liming + NPK+ FTE (fritted trace elements); liming + NPK + Zn, and liming + NPK + FTE + overseeding of Marandu grass (Brachiaria brizantha cv. Marandu). The combinations of liming and fertilization did not influence the chemical composition of the pasture. Liming + NPK + FTE + overseeding was superior in terms of biomass productivity when compared to the control treatment and did not differ from the other treatments. The mean concentrations of N, P, Ca and Mg in the aerial part of Brachiaria grass were not influenced by the fertilization combinations. Evaluation of total N export by the plant revealed a significant effect, with the liming + NPK + FTE + overseeding treatmentbeing superior (75.76%) to the control and liming treatments, which did not differ from one another. The use of liming and fertilization, in a single application, is not sufficient to completely recover or to increase the productivity and quality of Brachiaria grass. Overseeding of Marandu grass onBrachiaria pastures, in conjunction with liming and fertilization, is a good alternative to increase the productivity and to improve the quality of pastures in an advanced stage of degradation...
Assuntos
24444 , Pastagens , Produtos Agrícolas , EstercoRESUMO
O suprimento de nutrientes constitui-se em importante fator na nutrição da plantaforrageira, refletindo no aumento de produtividade de massa seca (PMS) e melhoria da qualidade.A correta aplicação de fertilizantes em áreas de pastagens degradadas, ao fornecer nutrientes paraatender as necessidades metabólicas, promove o desenvolvimento das plantas forrageiras, e porconsequência, restabelece a cultura. Objetivou-se com esse trabalho avaliar o efeito de combinaçõesde calagem, adubação e sobressemeadura na recuperação do capim-braquiária (Brachiaria decumbensStapf cv. Basilisk), em estágio avançado de degradação. O delineamento experimental utilizadofoi em blocos casualizados com seis tratamentos e quatro repetições. Os tratamentos avaliadoscorrespondem a testemunha; calagem; calagem + NPK; calagem + NPK + FTE (fritted trace elements);calagem + NPK + Zn; e calagem + NPK + FTE + sobressemeadura de capim-marandu (Brachiariabrizantha cv. Marandu). As combinações de calagem e adubação não influenciaram a composiçãoquímica da pastagem. O tratamento com calagem + NPK + FTE + sobressemeadura foi superior naPMS em relação ao tratamento testemunha, não diferindo dos demais. As concentrações médias deN, P, Ca e Mg da parte aérea do capim-braquiária, não foram influenciadas pelas combinações deadubação. Na avaliação da exportação total de N pelas plantas, houve efeito significativo, sendoo tratamento com calagem + NPK + FTE + sobressemeadura superior (75,76%) aos tratamentostestemunha e calagem, que não diferiram entre si. A utilização de calagem e adubação, em únicaaplicação, não é suficiente para a completa recuperação e aumento da produtividade e qualidadedo capim-braquiária. O uso da sobressemeadura do capim-marandu, sobre pastagens de capimbraquiária,em conjunto com a calagem e a adubação, é uma boa alternativa para o aumento daprodutividade e melhoria na qualidade de pastagens em estado avançado de degradação...(AU)
The supply of nutrients is an important factor for pasture nutrition, increasing biomass productivity and improving forage quality. The correct application of fertilizers to degraded pasture areas promotes the development of forage plants and the consequent reestablishment of the culture by providing nutrients to meet the metabolic requirements of the plant. The objective of this study was to evaluate the effect of combinations of liming, fertilization and overseedingon the recovery of Brachiaria grass (Brachiaria decumbens Stapf cv. Basilisk) in an advanced stageof degradation. A randomized block design consisting of six treatments and four repetitions was used. The following treatments were evaluated: control; liming; liming + NPK; liming + NPK+ FTE (fritted trace elements); liming + NPK + Zn, and liming + NPK + FTE + overseeding of Marandu grass (Brachiaria brizantha cv. Marandu). The combinations of liming and fertilization did not influence the chemical composition of the pasture. Liming + NPK + FTE + overseeding was superior in terms of biomass productivity when compared to the control treatment and did not differ from the other treatments. The mean concentrations of N, P, Ca and Mg in the aerial part of Brachiaria grass were not influenced by the fertilization combinations. Evaluation of total N export by the plant revealed a significant effect, with the liming + NPK + FTE + overseeding treatmentbeing superior (75.76%) to the control and liming treatments, which did not differ from one another. The use of liming and fertilization, in a single application, is not sufficient to completely recover or to increase the productivity and quality of Brachiaria grass. Overseeding of Marandu grass onBrachiaria pastures, in conjunction with liming and fertilization, is a good alternative to increase the productivity and to improve the quality of pastures in an advanced stage of degradation...(AU)
Assuntos
24444 , Pastagens , Produtos Agrícolas , EstercoRESUMO
Kulp et al. (Reports, 15 August 2008, p. 967) described a bacterium able to photosynthetically oxidize arsenite [As(III)] via arsenate [As(V)] reductase functioning in reverse. Based on their phylogenetic analysis of As(V) reductase, they proposed that this enzyme was responsible for the anaerobic oxidation of As(III) in the Archean. We challenge this proposition based on paleogeochemical, bioenergetic, and phylogenetic arguments.
Assuntos
Arseniato Redutases/metabolismo , Arsenitos/metabolismo , Bactérias/metabolismo , Biofilmes , Fontes Termais/microbiologia , Fotossíntese , California , Oxirredução , FilogeniaRESUMO
The mechanisms by which gene products inhibit the conjugal transfer of IncP plasmids (e.g., RP1) have been little studied. We have isolated and characterized one such gene, fipA (624 nucleotides), from the SmaI (14.8 kb)-AatII (15.6 kb) region of pKM101(IncN). This gene, which is also conserved in other IncN plasmids, is transcribed in an anticlockwise direction, probably as part of a transfer operon that includes traHI. The FipA protein (24 kDa) appears to be cytoplasmic and, when expressed from a multicopy plasmid, retards the growth of Escherichia coli WP2. The mode of action of fipA was compared with that of the apparently unrelated pifC gene from F(IncFI). Both genes inhibit the transfer of IncPalpha and IncPbeta plasmids but to different degrees. They also inhibit the mobilization of RSF1010 (which requires the RP1 pilus genes and traG) but not of CloDF13 (which encodes a traG homolog). Evidence that traG was the specific target of inhibition was obtained in an artificial system in which cloned traG was used to enhance RSF1010 mobilization via the N pilus system. Such enhancement did not occur in the presence of fipA or pifC. The availability of an in vivo assay of PifC enabled us to show that F pif operon expression increased in cells carrying F'lac and traG, but only if the traG coding sequence was intact. This finding suggested that conjugal inhibition of RP1 was most likely due to a PifC-TraG protein interaction. On phenotypic grounds inhibition of traG by fipA is also likely to occur posttranscriptionally. Whether or not the selection of traG as the inhibition target is an evolutionary tactic to limit the spread of P plasmids, we anticipate that fipA and pifC will prove useful in further investigation of the conjugal roles of traG and its homologs.
Assuntos
Proteínas de Bactérias/genética , Conjugação Genética , Proteínas de Escherichia coli , Escherichia coli/genética , Fator F/genética , Proteínas de Membrana , Fatores de Iniciação de Peptídeos/genética , Fatores R/genética , Clonagem Molecular , Escherichia coli/metabolismo , Fator de Iniciação 3 em Eucariotos , Genes Bacterianos , Fatores de Iniciação de Peptídeos/metabolismoRESUMO
A previously unknown chemolithoautotrophic arsenite-oxidizing bacterium has been isolated from a gold mine in the Northern Territory of Australia. The organism, designated NT-26, was found to be a gram-negative motile rod with two subterminal flagella. In a minimal medium containing only arsenite as the electron donor (5 mM), oxygen as the electron acceptor, and carbon dioxide-bicarbonate as the carbon source, the doubling time for chemolithoautotrophic growth was 7.6 h. Arsenite oxidation was found to be catalyzed by a periplasmic arsenite oxidase (optimum pH, 5.5). Based upon 16S rDNA phylogenetic sequence analysis, NT-26 belongs to the Agrobacterium/Rhizobium branch of the alpha-Proteobacteria and may represent a new species. This recently discovered organism is the most rapidly growing chemolithoautotrophic arsenite oxidizer known.
Assuntos
Alphaproteobacteria/isolamento & purificação , Arsenitos/metabolismo , Ouro , Bactérias Gram-Negativas Quimiolitotróficas/isolamento & purificação , Mineração , Alphaproteobacteria/classificação , Alphaproteobacteria/fisiologia , Meios de Cultura , DNA Bacteriano/genética , DNA Ribossômico/genética , Bactérias Gram-Negativas Quimiolitotróficas/classificação , Bactérias Gram-Negativas Quimiolitotróficas/fisiologia , Dados de Sequência Molecular , Oxirredução , Filogenia , Reação em Cadeia da Polimerase , RNA Ribossômico 16S/genética , Análise de Sequência de DNARESUMO
Arsenate [As(V)]-respiring bacteria affect the speciation and mobilization of arsenic in the environment. This can lead to arsenic contamination of drinking water supplies and deleterious consequences for human health. Using molecular genetics, we show that the functional gene for As(V) respiration, arrA, is highly conserved; that it is required for As(V) reduction to arsenite when arsenic is sorbed onto iron minerals; and that it can be used to identify the presence and activity of As(V)-respiring bacteria in arsenic-contaminated iron-rich sediments. The expression of arrA thus can be used to monitor sites in which As(V)-respiring bacteria may be controlling arsenic geochemistry.
Assuntos
Archaea/metabolismo , Arseniatos/metabolismo , Bactérias/metabolismo , Bombas de Íon/genética , Complexos Multienzimáticos/genética , Shewanella/genética , Shewanella/metabolismo , Archaea/genética , ATPases Transportadoras de Arsenito , Arsenitos/metabolismo , Bactérias/genética , Sequência Conservada , Compostos Férricos/metabolismo , Genes Bacterianos , Bombas de Íon/metabolismo , Complexos Multienzimáticos/metabolismo , Oxirredução , Reação em Cadeia da PolimeraseRESUMO
Two sulfate-reducing bacteria, which also reduce arsenate, were isolated; both organisms oxidized lactate incompletely to acetate. When using lactate as the electron donor, one of these organisms, Desulfomicrobium strain Ben-RB, rapidly reduced (doubling time = 8 h) 5.1 mM arsenate at the same time it reduced sulfate (9.6 mM). Sulfate reduction was not inhibited by the presence of arsenate. Arsenate could act as the terminal electron acceptor in minimal medium (doubling time = 9 h) in the absence of sulfate. Arsenate was reduced by a membrane-bound enzyme that is either a c-type cytochrome or is associated with such a cytochrome; benzyl-viologen-dependent arsenate reductase activity was greater in cells grown with arsenate/sulfate than in cells grown with sulfate only. The second organism, Desulfovibrio strain Ben-RA, also grew (doubling time = 8 h) while reducing arsenate (3.1 mM) and sulfate (8.3 mM) concomitantly. No evidence was found, however, that this organism is able to grow using arsenate as the terminal electron acceptor. Instead, it appears that arsenate reduction by the Desulfovibrio strain Ben-RA is catalyzed by an arsenate reductase that is encoded by a chromosomally-borne gene shown to be homologous to the arsC gene of the Escherichia coli plasmid, R773 ars system.