RESUMO
A maltotriose-forming amylase (G3Amy) from Kitasatospora sp. MK-1785 was successfully isolated from a soil sample by inhibiting typical extracellular α-amylases using a proteinaceous α-amylase inhibitor. G3Amy was purified from the MK-1785 culture supernatant and characterized. G3Amy produced maltotriose as the principal product from starch and was categorized as an exo-α-amylase. G3Amy could also transfer maltotriose to phenolic and alcoholic compounds. Therefore, G3Amy can be useful for not only maltotriose manufacture but also maltooligosaccharide-glycoside synthesis. Further, the G3Amy gene was cloned and expressed in Escherichia coli cells. Analysis of its deduced amino acid sequence revealed that G3Amy consisted of an N-terminal GH13 catalytic domain and two C-terminal repeat starch-binding domains belonging to CBM20. It is suggested that natural G3Amy was subjected to proteolysis at N-terminal region of the anterior CBM20 in the C-terminal region. As with natural G3Amy, recombinant G3Amy could produce and transfer maltotriose from starch.
Assuntos
Amilases/genética , Amilases/metabolismo , Streptomycetaceae/enzimologia , Streptomycetaceae/genética , Trissacarídeos/metabolismo , Clonagem Molecular , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Escherichia coli/enzimologia , Escherichia coli/genética , Expressão Gênica , Hidrólise , Dados de Sequência Molecular , Estrutura Terciária de Proteína , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Microbiologia do Solo , Amido/metabolismo , Streptomycetaceae/classificação , Streptomycetaceae/isolamento & purificaçãoRESUMO
Prostaglandin (PG) E(2) promotes osteoclastic cell differentiation, but the physiological function of PGF(2alpha) remains unclear. We examined the physiological effects of PGF(2alpha) on osteoclast differentiation using a murine cell line, RAW264, and the column-purified murine bone marrow cells, both of which are differentiable into osteoclast-like multi-nuclear cells. Although PGF(2alpha) did not affect the number of differentiated osteoclasts, PGF(2alpha) reduced the bone resorption activity of osteoclasts developed from both cell types in a pit formation assay. Thus, PGF(2alpha) inhibits bone resorption without affecting the number of osteoclasts, providing a novel molecular mechanism underlying bone metabolism.
Assuntos
Reabsorção Óssea/metabolismo , Dinoprosta/farmacologia , Osteoclastos/efeitos dos fármacos , Osteoclastos/metabolismo , Animais , Células da Medula Óssea/efeitos dos fármacos , Células da Medula Óssea/metabolismo , Diferenciação Celular , Linhagem Celular , Núcleo Celular/metabolismo , Camundongos , Osteoclastos/citologia , Receptores de Prostaglandina/metabolismo , Transdução de Sinais/efeitos dos fármacosRESUMO
The solidification and stabilization of municipal solid waste (MSW) fly ash for the purpose of minimizing the geo-environmental impact caused by toxic heavy metals as well as ensuring engineering safety (strength and soaking durability) are experimentally evaluated. The mixtures of MSW fly ash stabilized with cement and fluidized bed combustion coal fly ash (FCA) were used for unconfined compressive strength tests, leachate tests, and soaking tests. The behavior of soluble salts contained in the MSW fly ash significantly affects strength development, soaking durability, and the hardening reaction of the stabilized MSW fly ash mixtures. The cement stabilization of the MSW fly ash does not have enough effect on strength development and soaking durability. The addition of cement only contributes to the containment of heavy metals due to the high level of alkalinity. When using FCA as a stabilizing agent for MSW fly ash, the mixture exhibits high strength and durability. However, the Cd leachate cannot be prevented in the early stages of curing. Using a combination of cement and FCA as a MSW fly ash stabilizer can attain high strength, high soaking durability, and the containment of heavy metals. The stabilized MSW fly ash with cement and FCA can be practically applied to embankments.