RESUMO
Ligustroflavone is one major compound contained in active fraction from Fructus Ligustri Lucidi (the fruit of Ligustrum lucidum), which could regulate parathyroid hormone (PTH) levels and improve calcium balance by acting on calcium-sensing receptors (CaSR). This study aimed to explore the potency of ligustroflavone as a CaSR antagonist and its protective effects against diabetic osteoporosis in mice. LF interacted well with the allosteric site of CaSR shown by molecular docking analysis, increased PTH release of primary parathyroid gland cells and suppressed extracellular calcium influx in HEK-293 cells. The serum level of PTH attained peak value at 2 h and maintained high during the period of 1 h and 3 h than that before treatment in mice after a single dose of LF. Treatment of diabetic mice with LF inhibited the decrease in calcium level of serum and bone and the enhancement in urinary calcium excretion as well as elevated circulating PTH levels. Trabecular bone mineral density and micro-architecture were markedly improved in diabetic mice upon to LF treatment for 8 weeks. LF reduced CaSR mRNA and protein expression in the kidneys of diabetic mice. Taken together, ligustroflavone could transiently increase PTH level and regulate calcium metabolism as well as prevent osteoporosis in diabetic mice, suggesting that ligustroflavone might be an effective antagonist on CaSR.
Assuntos
Apigenina/farmacologia , Complicações do Diabetes/complicações , Glicosídeos/farmacologia , Ligustrum/química , Osteoporose/etiologia , Osteoporose/prevenção & controle , Receptores de Detecção de Cálcio/antagonistas & inibidores , Animais , Apigenina/administração & dosagem , Apigenina/isolamento & purificação , Densidade Óssea/efeitos dos fármacos , Cálcio/metabolismo , Osso Esponjoso/metabolismo , Células Cultivadas , Expressão Gênica/efeitos dos fármacos , Glicosídeos/administração & dosagem , Glicosídeos/isolamento & purificação , Células HEK293 , Humanos , Rim/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Glândulas Paratireoides/citologia , Glândulas Paratireoides/metabolismo , Hormônio Paratireóideo/metabolismo , Receptores de Detecção de Cálcio/genética , Receptores de Detecção de Cálcio/metabolismo , Fatores de TempoRESUMO
A colistin-resistant Escherichia coli isolate from a commercial poultry farm in China carried two colistin resistance genes, mcr-1 and variant of mcr-3, in an IncP plasmid. The variant of the mcr-3 gene, named mcr-3.11, encoded two amino acid substitutions compared with the mcr-3 gene. A novel genetic structure, ISKpn40-mcr-3-dgkA-ISKpn40, might be the key element mediating the translocation of mcr-3 through the formation of a circular form. The mcr-1 and mcr-3 genes, which are colocated on a plasmid, might pose a huge threat to public health.
Assuntos
Colistina/farmacologia , Proteínas de Escherichia coli/metabolismo , Escherichia coli/efeitos dos fármacos , Escherichia coli/metabolismo , Plasmídeos/genética , Polimixinas/farmacologia , Animais , Antibacterianos , Galinhas , Farmacorresistência Bacteriana , Escherichia coli/genética , Proteínas de Escherichia coli/genética , Fazendas , Testes de Sensibilidade Microbiana , Transferases (Outros Grupos de Fosfato Substituídos)/genética , Transferases (Outros Grupos de Fosfato Substituídos)/metabolismoRESUMO
A novel 65.8-kb multidrug resistance transposon, designated Tn6450, was characterized in a Proteus mirabilis isolate from chicken in China. Tn6450 contains 18 different antimicrobial resistance genes, including cephalosporinase gene blaDHA-1 and fluoroquinolone resistance genes qnrA1 and aac(6')-Ib-cr It carries a class 1/2 hybrid integron composed of intI2 and a 3' conserved segment of the class 1 integron. Tn6450 is derived from Tn7 via acquisition of new mobile elements and resistance genes.
Assuntos
Elementos de DNA Transponíveis/genética , Farmacorresistência Bacteriana Múltipla/genética , Proteus mirabilis/genética , Animais , Antibacterianos/farmacologia , Galinhas , China , DNA Bacteriano/genética , Fluoroquinolonas/farmacologia , Integrons/genética , Proteus mirabilis/efeitos dos fármacosRESUMO
The novel 63,558-bp plasmid pSA-01, which harbors nine antibiotic resistance genes, including cfr, erm(C), tet(L), erm(T), aadD, fosD, fexB, aacA-aphD, and erm(B), was characterized in Staphylococcus arlettae strain SA-01, isolated from a chicken farm in China. The colocation of cfr and fosD genes was detected for the first time in an S. arlettae plasmid. The detection of two IS431-mediated circular forms containing resistance genes in SA-01 suggested that IS431 may facilitate dissemination of antibiotic resistance genes.
Assuntos
Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Farmacorresistência Bacteriana Múltipla/genética , Fosfomicina/farmacologia , Plasmídeos/química , Infecções Estafilocócicas/veterinária , Staphylococcus/genética , Animais , Proteínas de Bactérias/metabolismo , Galinhas , China/epidemiologia , Fazendas , Sequenciamento de Nucleotídeos em Larga Escala , Testes de Sensibilidade Microbiana , Plasmídeos/metabolismo , Doenças das Aves Domésticas/epidemiologia , Doenças das Aves Domésticas/microbiologia , Infecções Estafilocócicas/epidemiologia , Infecções Estafilocócicas/microbiologia , Staphylococcus/efeitos dos fármacos , Staphylococcus/isolamento & purificação , Staphylococcus/metabolismoRESUMO
IncC plasmids are of great concern as vehicles of broad-spectrum cephalosporins and carbapenems resistance genes blaCMY and blaNDM. The aim of this study was to sequence and characterize a multidrug resistance (MDR) IncC plasmid (pPm14C18) recovered from Proteus mirabilis. pPm14C18 was identified in a CMY-2-producing P. mirabilis isolate from chicken in China in 2014, and could be transferred to Escherichia coli conferring an MDR phenotype. Whole genome sequencing confirmed pPm14C18 was a novel type 1/2 hybrid IncC plasmid 165,992bp in size, containing fifteen antimicrobial resistance genes. It harboured a novel MDR mosaic region comprised of a hybrid Tn21tnp-pDUmer, in which blaCTX-M-65, dfrA32 and ereA were firstly reported in IncC plasmid. Phylogenetic relationship reconstruction based on the nucleotide sequences of the 52 IncC backbones showed all type 1 IncC plasmids were clustered into one clade, and then merged with pPm14C18 and finally with the type 2 IncC plasmids and another type 1/2 hybrid IncC plasmid pYR1. The MDR IncC plasmids in P. mirabilis of animal origin might threaten public health, which should be drawn more attention.
Assuntos
Proteínas de Bactérias/genética , Farmacorresistência Bacteriana Múltipla/genética , Genes Bacterianos/genética , Plasmídeos/genética , Proteus mirabilis/genética , Animais , Galinhas/microbiologia , China , Escherichia coli/genética , FilogeniaRESUMO
Recently, a novel variant of the CTX-M enzyme, CTX-M-98, was detected in Escherichia coli isolates from food animals. However, few plasmids carrying blaCTX-M-98 have been fully characterized. In this study, we sequenced the complete pHeBE7 plasmid, an 86,015-bp plasmid that contains the blaCTX-M-98b, blaTEM-1, rmtB, and traT genes, using whole-genome sequencing. The backbone of pHeBE7 shows a high similarity (>99%) to pMC-NDM, which carries the blaNDM-1 gene, however its mosaic regions remain relatively unique among sequenced plasmids. We discovered that a typical ISEcp1-blaCTX-M-IS903 element in the mosaic region harbors the blaCTX-M-98b gene. Conjugation and growth competition assays indicate that pHeBE7 can be easily transmitted and that it confers a limited fitness cost to the recipient cell. The genetic characterization of pHeBE7 may improve our knowledge of how antibiotic resistance disseminates in enterobacteria.
Assuntos
Escherichia coli/genética , Plasmídeos/genética , Animais , Antibacterianos/farmacologia , Galinhas/microbiologia , Conjugação Genética , Escherichia coli/isolamento & purificação , Genes Bacterianos , Fígado/microbiologia , Testes de Sensibilidade Microbiana , Doenças das Aves Domésticas/microbiologia , Virulência/genética , Resistência beta-Lactâmica/genética , beta-Lactamases/genética , beta-Lactamas/farmacologiaRESUMO
The mcr-1 gene was detected in 5.11% (58/1136) of Escherichia coli isolates of chicken origin from 13 provinces in China. A novel mcr-1 variant, named mcr-1.3, encoding an Ile-to-Val functional variant of MCR-1 was identified in a sequence type 155 (ST155) strain. An mcr-1.3-containing IncI2 plasmid, pHeN867 (60,757 bp), was identified. The transfer of pHeN867 led to a 32-fold increase in the MIC of colistin in the recipient, exhibiting an effect on colistin resistance that was similar to that of mcr-1.
Assuntos
Antibacterianos/farmacologia , Galinhas/microbiologia , Colistina/farmacologia , Proteínas de Escherichia coli/genética , Escherichia coli/genética , Doenças das Aves Domésticas/microbiologia , Animais , Sequência de Bases , China , Farmacorresistência Bacteriana/genética , Escherichia coli/efeitos dos fármacos , Escherichia coli/isolamento & purificação , Infecções por Escherichia coli/tratamento farmacológico , Infecções por Escherichia coli/veterinária , Transferência Genética Horizontal , Testes de Sensibilidade Microbiana , Plasmídeos/genética , Análise de Sequência de DNA , beta-Lactamases/genéticaRESUMO
Sixteen different sequence types (STs) of Escherichia coli isolates from a commercial swine farm in China were confirmed to coharbor the carbapenem resistance gene blaNDM-5 and the colistin resistance gene mcr-1 Whole-genome sequencing revealed that blaNDM-5 and mcr-1 were located on a 46-kb IncX3 plasmid and a 32-kb IncX4 plasmid, respectively. The two plasmids can transfer together with a low fitness cost, which might explain the presence of various STs of E. coli coharboring blaNDM-5 and mcr-1.
Assuntos
Farmacorresistência Bacteriana Múltipla/genética , Infecções por Escherichia coli/veterinária , Proteínas de Escherichia coli/genética , Escherichia coli/genética , Doenças dos Suínos/epidemiologia , beta-Lactamases/genética , Animais , Antibacterianos/farmacologia , Carbapenêmicos/farmacologia , China/epidemiologia , Colistina/farmacologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Escherichia coli/isolamento & purificação , Infecções por Escherichia coli/epidemiologia , Infecções por Escherichia coli/microbiologia , Proteínas de Escherichia coli/metabolismo , Expressão Gênica , Transferência Genética Horizontal , Aptidão Genética , Genótipo , Plasmídeos/química , Plasmídeos/genética , Plasmídeos/metabolismo , Suínos , Doenças dos Suínos/microbiologia , beta-Lactamases/metabolismoRESUMO
SXT/R391 integrative and conjugative elements (ICEs) were detected in 8 out of 125 Proteus mirabilis isolates from food-producing animals in China. Whole-genome sequencing revealed that seven ICEs were identical to ICEPmiJpn1, carrying the cephalosporinase gene blaCMY-2. Another one, designated ICEPmiChn1, carried five resistance genes. All eight ICEs could be transferred to Escherichia coli via conjugation. The results highlight the idea that animal farms are important reservoir of the SXT/R391 ICE-containing P. mirabilis.
Assuntos
Elementos de DNA Transponíveis/genética , Farmacorresistência Bacteriana Múltipla/genética , Escherichia coli/genética , Proteus mirabilis/genética , Proteus mirabilis/isolamento & purificação , beta-Lactamases/genética , Animais , Proteínas de Bactérias/genética , Sequência de Bases , Galinhas , China , Conjugação Genética/genética , DNA Bacteriano/genética , Escherichia coli/efeitos dos fármacos , Fazendas , Genoma , Testes de Sensibilidade Microbiana , Doenças das Aves Domésticas/microbiologia , Análise de Sequência de DNA , Suínos , Doenças dos Suínos/microbiologiaRESUMO
Four different Salmonella genomic island 1 (SGI1) variants, including two novel variants, were characterized in one Salmonella enterica serovar Rissen sequence type ST1917 isolate and three Proteus mirabilis isolates from swine farms in China. One novel variant was derived from SGI1-B with the backbone gene S021 disrupted by a 12.72-kb IS26 composite transposon containing the dfrA17-aadA5 cassettes and macrolide inactivation gene cluster mphA-mrx-mphR. The other one was an integron-free SGI1 and contained a 183-bp truncated S025 next to IS6100 and S044.
Assuntos
Ilhas Genômicas/genética , Proteus mirabilis/genética , Salmonella/genética , Animais , China , Elementos de DNA Transponíveis/genética , Variação Genética , Dados de Sequência Molecular , Família Multigênica/efeitos dos fármacos , Salmonella enterica/efeitos dos fármacos , Salmonella enterica/genética , Suínos/microbiologiaRESUMO
Six out of the 64 studied Proteus mirabilis isolates from 11 poultry farms in China contained Salmonella genomic island 1 (SGI1). PCR mapping showed that the complete nucleotide sequences of SGI1s ranged from 33.2 to 42.5 kb. Three novel variants, SGI1-W, SGI1-X, and SGI1-Y, have been characterized. Resistance genes lnuF, dfrA25, and qnrB2 were identified in SGI1 for the first time.
Assuntos
Farmacorresistência Bacteriana Múltipla/genética , Genes Bacterianos , Ilhas Genômicas , Doenças das Aves Domésticas/epidemiologia , Infecções por Proteus/epidemiologia , Proteus mirabilis/genética , Criação de Animais Domésticos , Animais , Antibacterianos/farmacologia , Sequência de Bases , Galinhas , China/epidemiologia , Mapeamento Cromossômico , Testes de Sensibilidade Microbiana , Dados de Sequência Molecular , Aves Domésticas , Doenças das Aves Domésticas/tratamento farmacológico , Doenças das Aves Domésticas/microbiologia , Infecções por Proteus/tratamento farmacológico , Infecções por Proteus/microbiologia , Proteus mirabilis/efeitos dos fármacos , Proteus mirabilis/isolamento & purificaçãoRESUMO
A laboratory experiment with orthogonal design was conducted to study the effects of factors salinity, temperature, and light intensity on the growth and toxin production of Chattonella marina. Three levels of salinity (22, 33, and 45), temperature (20 degrees C, 25 degrees C, and 30 degrees C) and light intensity (2000, 3000, and 4500 lx) were installed. In all treatments, the three factors had no significant effects on the growth of C. marina, but salinity significantly affected the toxin production of C. marina. Under salinity 45, temperature 30 degrees C and light intensity 2000 lx, C. marina had the maximal growth rate; under salinity 22, temperature 20 degrees C and light intensity 4500 lx, the toxin production of C. marina was the maximal. Low salinity was not favorable to the C. marina growth but favorable to its haemolytic toxin production. When the growth of C. marina was limited, its haemolytic toxin production increased.