The presence of phytase activity was demonstrated in 26 strains of rabbit cecal bacteria. In 25 strains a low phytase activity, 0.10-0.62 micromol phosphate released per min per mg protein, was found. High activity (2.61 micromol/min per mg protein) was found in the strain PP2 identified as Enterococcus hirae. Phytase activity was cell-associated, being higher in the cell extract than in the cell walls. Extracellular phytase activity and cell-associated phosphatase activity were not detected. Phytase activity was optimal around pH 5.0, which is below the physiological cecal pH range. The K (m) determined using the Lineweaver-Burk plot was 0.19 micromol/mL. Cations Fe(3+), Cu(2+) and Zn(2+) at 0.5 mmol/L decreased phytase activity in sonicated cells of E. hirae by 99.4, 90.7 and 96.5 %, respectively. In contrast, Mg(2+) increased activity by 11.0 %. Characteristics of E. hirae phytase (pH optimum, K (m), cation sensitivity) were similar to those of other bacterial phytases reported in the literature. Other bacteria with a high phytase activity may be present in the rabbit cecum but remain to be identified.

• MeSH
• 6-fytasa chemie   metabolismus   MeSH
• Bacteria chemie   enzymologie   izolace a purifikace   MeSH
• bakteriální proteiny chemie   metabolismus   MeSH
• cékum mikrobiologie   MeSH
• Enterococcus chemie   genetika   izolace a purifikace   MeSH
• kinetika MeSH
• králíci MeSH
• stabilita enzymů MeSH
• zvířata MeSH
• Check Tag
• králíci MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 6-fytasa MeSH
• bakteriální proteiny MeSH

Serratia plymuthica strain IC1270 isolated from the rhizosphere, possessing antagonistic activity towards a wide range of plant-pathogenic fungi, is able to hydrolyze phytate. Phytase activity was found intracellularly, while no activity was detected in the culture liquid. Optimum activity was found at pH 4-5; it completely disappeared at pH > 7.0 and 2.5. Phytase production was practically absent in the exponential phase and reached a maximum in the late stationary phase. Mutations of genes grrA and grrS, encoding GacA/GacS-like 2-component global regulatory system, or in gene rpoS encoding the sigma factor RpoS subunit of RNA polymerase, led to a deficiency in phytase production. Introduction into mutants of the respective wild-type genes cloned into the wide-range plasmid pJFF224-NX under the control of the bacteriophage T4 gene 32 promoter complemented this deficiency. This is the first report implicating the GacA/GacS global regulators and RpoS factor in phytase production in bacteria.

• MeSH
• 6-fytasa chemie   genetika   metabolismus   MeSH
• bakteriální proteiny chemie   genetika   metabolismus   MeSH
• kořeny rostlin mikrobiologie   MeSH
• regulace genové exprese enzymů * MeSH
• regulace genové exprese u bakterií * MeSH
• Serratia chemie   enzymologie   genetika   MeSH
• sigma faktor genetika   metabolismus   MeSH
• stabilita enzymů MeSH
• Vitis mikrobiologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 6-fytasa MeSH
• bakteriální proteiny MeSH
• GacA protein, Bacteria MeSH Prohlížeč
• sigma faktor MeSH

Cryptococcus laurentii strain AL27 demonstrating significant potential for intracellular phytase production was selected by 2-step screening of Antarctic yeasts. The strain showed increased phytase activity in a culture medium with 40 g/L sucrose, KH2PO4 providing 5 mg/L phosphorus, and cultivation temperature of 24 degrees C, which relates it to psychrotrophic microorganisms. The enzyme kinetic characteristics according to sodium phytate were Km = 0.98 mmol/L, vlim = 33.3 micromol g(-1) min(-1). The enzyme had maximum activity at 40 degrees C and acted within a wide pH range: from 2.0 to 5.5, which is of positive significance for its direct inclusion into the feed of monogastric animals.

• MeSH
• 6-fytasa chemie   genetika   metabolismus   MeSH
• Cryptococcus enzymologie   genetika   izolace a purifikace   metabolismus   MeSH
• fungální proteiny chemie   genetika   metabolismus   MeSH
• kinetika MeSH
• půdní mikrobiologie * MeSH
• stabilita enzymů MeSH
• teplota MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Antarktida MeSH
• Názvy látek
• 6-fytasa MeSH
• fungální proteiny MeSH