Yoko Yakabe

National Institute of Livestock and Grassland Science, Ibaragi, Ōsaka, Japan

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Publications (7)13.47 Total impact

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    ABSTRACT: 1. The aim of this work was to select lactic acid bacteria (LAB) strains from chicks and hens of egg-laying strains for potential use to control Salmonellae. 2. Nineteen LAB strains obtained from culture collections, and 24 strains isolated from excreta of laying hens and chicks, were evaluated for inhibitory capacities against two Salmonella serotypes using a "Spot-the-lawn" technique and other in vitro properties that could be predictive of antimicrobial activity. 3. The size of the inhibition zone differed slightly between Salmonella serotypes, however, the mean size of the Salmonella inhibition zone differed greatly among the LAB strains. Lactobacillus salivarius, L. plantarum, L. rhamnosus and L. reuteri exhibited powerful inhibitory effects to each Salmonella strain. 4. The result of the acid tolerance test showed that all L. salivarius, L. kitasatonis strains and each of L. ingluviei cannot survive in a low pH environment. In the bile acid tolerance assay, growth was inhibited in all strains, except L. kitasatonis HE4, and a large inhibition was observed in most of the L. salivarius and L. crispatus strains. 5. The results demonstrate that some LAB of poultry origin were able to inhibit the growth of Salmonella and survive simulated passage through the gastrointestinal tract. The selected LAB could act in the lower gastrointestinal tract to prevent salmonellosis in poultry.
    British Poultry Science 04/2012; 53(2):183-9. · 1.15 Impact Factor
  • The Journal of Poultry Science 01/2009; 46(2):116-122. · 0.68 Impact Factor
  • Kazuki Nakashima, Yoko Yakabe
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    ABSTRACT: In skeletal muscle, AMP-activated protein kinase (AMPK) is a metabolic master switch regulating glucose and lipid metabolism. Recently, AMPK has been implicated in the control of protein synthesis in skeletal muscle, but the effect of AMPK activation on myofibrillar protein degradation has yet to be elucidated. The present study was designed to examine the effect of 5-aminoimidazole-4-carboxamide-1-beta-D-ribonucleoside (AICAR)-induced AMPK signaling on effector mechanisms of myofibrillar protein degradation and the expression of atrophy-related genes (atrogin-1/MAFbx, MuRF1, proteasome C2 subunit, calpains, cathepsin B, and caspase-3) in C2C12 myotubes. AICAR stimulated myofibrillar protein degradation (as measured by N(tau)-methylhistidine release), while also increasing the levels of atrogin-1/MAFbx and MuRF1 mRNA, but the expression of other atrophy-related genes was not enhanced by AICAR treatment in C2C12 myotubes. AICAR also stimulated the level of FOXO transcription factors mRNA and protein in C2C12 myotubes. These results indicate that activation of AMPK stimulates myofibrillar protein degradation through the expression of atrogin-1/MAFbx and MuRF1 by increasing FOXO transcription factors in skeletal muscles.
    Bioscience Biotechnology and Biochemistry 02/2008; 72(6):2008E2. · 1.27 Impact Factor
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    ABSTRACT: We previously reported that L-leucine suppresses myofibrillar proteolysis in chick skeletal muscles. In the current study, we compared the effects of L- and D-enantiomers of leucine on myofibrillar proteolysis in skeletal muscle of chicks. We also assessed whether leucine itself or its metabolite, alpha-ketoisocaproate (alpha-KIC), mediates the effects of leucine. Food-deprived (24 h) chicks were orally administered 225 mg/100 g body weight L-leucine, D-leucine or alpha-KIC and were sacrificed after 2 h. L-Leucine administration had an obvious inhibitory effect on myofibrillar proteolysis (plasma N(tau)-methylhistidine concentration) in chicks while D-leucine and alpha-KIC were much more effective. We also examined the expression of the proteolytic-related genes (ubiquitin, proteasome, m-calpain and cathepsin B) by real-time PCR of cDNA in chick skeletal muscles. Ubiquitin mRNA expression was decreased by D-leucine and alpha-KIC but not L-leucine. Proteasome and m-calpain mRNA expressions as well as cathepsin B mRNA expression were likewise decreased by L-leucine, D-leucine and alpha-KIC. These results indicate that D-leucine and alpha-KIC suppress proteolytic-related genes, resulting in an decrease in myofibrillar proteolysis while L-leucine is much less effective in skeletal muscle of chicks, may be explain by conversion of D-leucine to alpha-KIC.
    Amino Acids 10/2007; 33(3):499-503. · 3.91 Impact Factor
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    ABSTRACT: We examined the effects of orally administered glycine on myofibrillar proteolysis in food-deprived chicks. Food-deprived (24 h) chicks were orally administered 57, 113, and 225 mg glycine/100 g body weight and killed after 2 h. The plasma N(tau)-methylhistidine concentration, used as myofibrillar proteolysis, was decreased by glycine. We also examined the expression of proteolytic-related genes by real-time PCR of cDNA from chick skeletal muscles. The mRNA expression of atrogin-1/MAFbx, proteasome C2 subunit, m-calpain large subunit, and cathepsin B was decreased by glycine in a dose-dependent manner. The plasma corticosterone concentration was also decreased by glycine, but the plasma insulin concentration was unaffected. These results indicate that orally administered glycine suppresses myofibrillar proteolysis and expression of proteolytic-related genes of skeletal muscle by decreasing the plasma corticosterone concentration in chicks.
    Amino Acids 08/2007; 35(2):451-6. · 3.91 Impact Factor
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    ABSTRACT: This experiment was conducted to study the effects of fasting and refeeding on expression of the atrogin-1 and Akt/FOXO signaling pathway in skeletal muscle of chicks. Chicks were fasted for 24 h and refed for 2 h. Atrogin-1 mRNA expression was increased by fasting, and their increment was reduced by refeeding. Phosphorylations of Akt and FOXO1 were not decreased by fasting, but, they were increased by refeeding. These results indicate that refeeding stimulates phosphorylation of Akt/FOXO, resulting in a decrease in atrogin-1 expression in skeletal muscle of chicks.
    Bioscience Biotechnology and Biochemistry 12/2006; 70(11):2775-8. · 1.27 Impact Factor
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    ABSTRACT: We examined the effects of orally administrated amino acids on myfibrillar proteolysis in food-deprived chicks. Plasma N(tau)-methylhistidine concentration, as an index of myofibrillar proteolysis, was decreased by the administration of Glu, Gly, Ala, Leu, Ile, Ser, Thr, Met, Trp, Asn, Gln, Pro, Lys and Arg but not by Asp, Val, Phe, Tyr or His to chicks. Orally administrated Cys was fatal to chicks. These results indicate that oral Glu, Gly, Ala, Leu, Ile, Ser, Thr, Met, Trp, Asn, Gln, Pro, Lys and Arg administration suppressed myofibrillar proteolysis in chicks.
    Bioscience Biotechnology and Biochemistry 09/2006; 70(8):1975-8. · 1.27 Impact Factor