Experimental assessment of the pathogenicity of H5N1 influenza A viruses isolated in Japan     

Mase M  Imada T  Nakamura K  Tanimura N  Imai K  Tsukamoto K  Yamaguchi S 《Avian diseases》2005,49(4):582-584

We examined the pathogenicity for chickens of two H5N1 avian influenza viruses isolated in Japan, A/chicken/ Yamaguchi/7/2004 (Ck/Yamaguchi/7/04) isolated from outbreaks in commercial layer chickens, and A/duck/Yokohama/aq10/ 2003 (Dk/Yokohama/aq10/03) isolated from duck meat imported from China. All chickens inoculated intranasally with either strain died, and the viruses were reisolated from all organs examined. However, both the mean time of onset of clinical signs and the mean death time of Ck/Yamaguchi/7/04 were shorter than those of Dk/Yokohama/aq10/03.  相似文献   

Advanced molecular immunoassay system for immunobiotic lactic acid bacteria using a transfectant of Toll-like receptor 2   总被引：1，自引：1，他引：1  

Masanori TOHNO  Takeshi SHIMOSATO  Yasushi KAWAI  Hisashi ASO  Shuji IKEGAMI  Naoki TAKETOMO  Tadao SAITO  Haruki KITAZAWA 《Animal Science Journal》2007,78(2):195-205

Toll‐like receptor 2 (TLR2) is a receptor for a variety of microbial components, and it also mediates activation signals in the cell relating to the innate immune system. In order to evaluate the precise molecular immunoregulation by various strains of lactic acid bacteria (LAB) via TLR2, the swine TLR2 (sTLR2)‐expressing transfectant was constructed using human embryonic kidney (HEK) 293 cells. It is demonstrated that intact immunobiotic LAB can induce immune responses through TLR2, and that different nuclear factor‐κB (NF‐κB) activities of various strains can be accurately detected by sTLR2‐expressing HEK293 cells. Furthermore, cellular activation of NF‐κB via TLR2 is reflected in enhanced binding and uptake of LAB. The sTLR2‐expressing HEK293 cells were also useful for characterizing the expression pattern of type I helper T (Th1) and type II helper T (Th2) cytokines by the stimulation of immunobiotic LAB. These results suggest that sTLR2‐expressing HEK293 cells may be useful in certain molecular immunoassay systems for producing new physiologically functional foods with intestinal immunomodulatory abilities, such as the maintenance of Th1/Th2 polarization.  相似文献   

Feed intake, lactation performance, blood metabolites and fertility in early lactation dairy cows grazing a timothy pasture   总被引：2，自引：0，他引：2  

Tsutomu OHGI  Satoshi HARA  Tadao OZEKI  Mamiko FUJITA  Osamu SAKAI  Hirotaka KASHUYA  Akira DOUKOSHI  Kazuyuki NISHIMURA 《Animal Science Journal》2006,77(2):215-222

The present study was conducted to investigate feed intake, milk yield, milk composition, blood metabolites and fertility in early lactation dairy cows grazing a timothy pasture. Fourteen multiparous Holstein cows that calved between 20 May and 19 July were used over a 3‐year period. The stocking rate was 3.6–4.3 cow/ha. Concentrates were fed separately at 9.5–11.5 kg/day per cow (dry matter basis) from 1 to 13 weeks postparturition. Herbage intake was estimated using chromium oxide as an indigestible marker. The mean contents of crude protein, total digestible nutrients and neutral detergent fiber of pasture during the 3‐year study period were 22.3%, 71.8% and 51.7%, and those of total diet were 18.9%, 77.3% and 40.3%, respectively. The mean herbage dry matter intake was 13.0 kg/day from 2 to 13 weeks postparturition during the study, total dry matter intake was 23.7 kg/day, the total digestible nutrients sufficiency rate was 105%, milk yield was 39.7 kg/day, and milk fat percentage was 3.30%. The decrease in bodyweight postparturition was slight. Urea nitrogen concentrations in serum were below 18.3 mg/dL. The mean days to first estrus and days open were 36 and 104 days, respectively. These results indicate that energy deficiency, decrease in bodyweight and fertility in early lactation barely occur when high producing dairy cows are fed enough grazing grass and suitable concentrates.  相似文献   

Identification of sialyl oligosaccharides including an oligosaccharide nucleotide in colostrum of an addax (Addax nasomaculatus) (Subfamily Antelopinae)          下载免费PDF全文

Khuukhenbaatar Ganzorig  Takuya Asakawa  Masashi Sasaki  Tadao Saito  Isao Suzuki  Kenji Fukuda  Tadasu Urashima 《Animal Science Journal》2018,89(1):167-175

Mammalian milk/colostrum usually contains milk oligosaccharides along with the predominant lactose. Although milk oligosaccharides of a variety of Bovidae species including cow, sheep and goat have been characterized, those of the addax, an Antelopinae species of the Bovidae, have not as yet been clarified. In this study, several sialyl oligosaccharides were purified from a sample of addax colostrum and characterized as follows: Neu5Ac(α2‐8)Neu5Ac(α2‐3)Gal(β1‐4)Glc, Neu5Gc(α2‐8)Neu5Gc(α2‐3)Gal(β1‐4)Glc, Neu5Ac(α2‐3)Gal(β1‐4)Glc, Neu5Ac(α2‐6)Gal(β1‐4)GlcNAc, Neu5Gc(α2‐3)Gal(β1‐4)Glc, Neu5Gc(α2‐6)Gal(β1‐4)Glc, Neu5Gc(α2‐6)Gal(β1‐4)GlcNAc. In addition, an oligosaccharide nucleotide Neu5Gc(α2‐6)Gal(β1‐4)GlcNAcα1‐UDP was characterized. Molecular species of a variety of sialyl oligosaccharides found in milk and colostrum of these Bovidae were compared.  相似文献   

Chemical characterization of milk oligosaccharides of the common wombat (Vombatus ursinus)          下载免费PDF全文

Kentaro Hirayama  Epi Taufik  Megumi Kikuchi  Tadashi Nakamura  Kenji Fukuda  Tadao Saito  Keith Newgrain  Brian Green  Michael Messer  Tadasu Urashima 《Animal Science Journal》2016,87(9):1167-1177

Previous structural characterizations of marsupial milk oligosaccharides have been performed in the tammar wallaby, red kangaroo, koala, common brushtail possum and the eastern quoll. To clarify the homology and heterogeneity of milk oligosaccharides among marsupial species, which could provide information on their evolution, the oligosaccharides of wombat milk carbohydrate were characterized in this study. Neutral and acidic oligosaccharides were isolated from the carbohydrate fractions of two samples of milk of the common wombat and characterized by ¹H‐nuclear magnetic resonance spectroscopy. The structures of six neutral saccharides were found to be Gal(β1‐4)Glc (lactose), Gal(β1‐3)Gal(β1‐4)Glc (3'‐galactosyllactose), Gal(β1‐3)Gal(β1‐3)Gal(β1‐4)Glc (3',3”‐digalactosyllactose), Gal(β1‐3)Gal(β1‐3)Gal(β1‐3)Gal(β1‐4)Glc, Gal(β1‐3)Gal(β1‐3)[Gal(β1‐4)GlcNAc(β1‐6)]Gal(β1‐4)Glc (galactosyl lacto‐N‐novopentaose I) and Gal(β1‐3)[Gal(β1‐4)GlcNAc(β1‐6)]Gal(β1‐3)[Gal(β1‐4)GlcNAc(β1‐6)]Gal(β1‐4)Glc (lacto‐N‐novooctaose), while those of six acidic saccharides were Neu5Ac(α2‐3)Gal(β1‐3)Gal(β1‐4)Glc. (sialyl 3'‐galactosyllactose), Neu5Ac(α2‐3)Gal(β1‐3)Gal(β1‐3)Gal(β1‐4)Glc (sialyl 3',3”‐digalactosyllactose), Neu5Ac(α2‐3)Gal(β1‐3)[Gal(β1‐4)GlcNAc(β1‐6)]Gal(β1‐4)Glc (sialyl lacto‐N‐novopentaose a), Gal(β1‐3)[Neu5Ac(α2‐3)Gal(β1‐4)GlcNAc(β1‐6)]Gal(β1‐4)Glc (sialyl lacto‐N‐novopentaose c), Neu5Ac(α2‐3)Gal(β1‐3)Gal(β1‐3)Gal(β1‐3)Gal(β1‐4)Glc,, Neu5Ac(α2‐3)Gal(β1‐3)Gal(β1‐3)[Gal(β1‐4)GlcNAc(β1‐6)]Gal(β1‐4)Glc and Gal(β1‐3)Gal(β1‐3)[Neu5Ac(α2‐3)Gal(β1‐4)GlcNAc(β1‐6)]Gal(β1‐4)Glc. In addition, small amounts of sulfated oligosaccharides but no oligosaccharides containing Neu5Gc or α(2–6) linked Neu5Ac were detected.  相似文献   

Development of molecular immunoassay system for probiotics via toll-like receptors based on food immunology   总被引：1，自引：1，他引：0  

Haruki KITAZAWA  Masanori TOHNO  Takeshi SHIMOSATO  Tadao SAITO 《Animal Science Journal》2008,79(1):11-21

Recent interest has focused on the importance of intestinal immunity for the host defense, but to date, not much is known about the underlying mechanisms. The toll‐like receptor (TLR) family plays an important role in host defense through recognizing bacterial pathogen‐associated molecular patterns. Our recent research on the physiological function of food products has investigated the immunoregulatory effects of probiotic lactic acid bacteria (LAB) via TLR. Studies of swine, which often substitute for a human model, have demonstrated intestinal immunoregulation by the probiotic LAB mediated by TLR in the gut. On the basis of our study, efforts have also been made to develop a molecular immunoassay system for probiotic LAB and find novel immunostimulatory DNA sequences from probiotics and high potential immunobiotic LAB strains via TLR signaling. These findings may provide important clues at the molecular level on TLR signal transduction pathways and recognition mechanisms for the ligands. They also provide impetus to further delineate the activation mechanism of the innate immune response. In addition to identifying immunoregulatory factor immunogenics from LAB, a better understanding of intestinal immune regulation through cytokine networks holds out promise for basic food immunology research and the development of immunobiotic foods to prevent specific diseases.  相似文献   

Bacteriocin production of probiotic Lactobacillus gasseri LA39 isolated from human feces in milk-based media     

Kensuke ARAKAWA  Yasushi KAWAI  Kenji FUJITANI  Junko NISHIMURA  Haruki KITAZAWA  Ken-ichi KOMINE  Kenzo KAI  Tadao SAITO 《Animal Science Journal》2008,79(5):634-640

The use of bacteriocins from Lactobacillus gasseri , a probiotic lactic acid bacterium, as bio-preservatives in the food industry and animal formulations has been limited because few strains of Lb. gasseri are cultivated and produce a bacteriocin in natural media such as milk and milk-based media. By the determination of the growth-supplements to milk among the 47 nutrients, Lb. gasseri JCM1131^T, LA39 and LA158 isolated from human feces were successfully cultured in reconstituted skim milk and cheese whey using proteose peptone as a nutrient supplement, where Lb. gasseri LA39 produced a useful bacteriocin, gassericin A, with effective growth-inhibiting activity against Gram-positive food-borne pathogens. The data suggest these developed low-cost safe media supporting enough production of bacteriocins by the probiotic Lb. gasseri LA39 could be used to improve the safe bio-preservation of foods and therapy of bovine mastitis, and extra cheese whey produced by cheese making industry is reused in the cultivation for probiotics effectively.  相似文献   

Selection of useful probiotic lactic acid bacteria from the Lactobacillus acidophilus group and their applications to functional foods     

Tadao SAITO 《Animal Science Journal》2004,75(1):1-13

In the present review, a new mass screening system for selecting probiotic strains from Lactobacillus (L) acidophilus group lactic acid bacteria (LAB) with strong adhesion to the human intestinal tract is described. Characteristics of antimicrobial peptides (bacteriocin), lactose‐hydrolyzing enzymes and immunostimulative oligo DNA motifs in L. gasseri strains are also described. Finally, the use of L. acidophilus LAB, selected by our screening method, that have strong adhesion to the human colonic mucosa in functional yogurt products is described. Adhesiveness to the human intestine is one of the most important characteristics of probiotic LAB. A new screening system that involves a combination of three methods is proposed: rat colonic mucin (RCM)‐micro plate assay, Carnoy's histochemical staining method and carbohydrate probe binding assay. By using an RCM‐coated poly‐vinylidene‐diflouride membrane that mimics the human colonic mucous layer, a new lectin was isolated and its structure was clarified by gene cloning. Furthermore, the structures and functions of a new cyclic bacteriocin (gassericin A), new lactose‐hydrolyzing enzymes, and new immunostimulating oligo DNA motifs from Lactobacillus gasseri (B₁ subgroup) were clarified. A new functional yogurt ‘Fit down’ is proposed, that is fermented by an adhesive strain of L. acidophilus LA67 selected by our screening and contains antihypertensive peptides derived from whey proteins by protease digestion. In the future, superior functional foods containing more effective probiotic LAB are expected to be developed by the use of the proposed mass screening system.  相似文献   

Chemical modification of a phenoxyfuranone‐type strigolactone mimic for selective effects on rice tillering or Striga hermonthica seed germination          下载免费PDF全文

Tadao Asami 《Pest management science》2016,72(11):2048-2053

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Insect growth regulators with hydrazide moiety inhibit strigolactone biosynthesis in rice     

Kojiro Kawada  Yasuyuki Sasaki  Tadao Asami  Shunsuke Yajima  Shinsaku Ito 《Journal of Pesticide Science》2022,47(1):43

Strigolactones (SLs) are carotenoid-derived plant hormones involved in several growth and developmental processes. Also, SLs are allelochemicals that induce the seed germination of root parasitic plants and the hyphal branching of arbuscular mycorrhizal fungi. In this study, to identify novel lead chemicals that inhibit SL biosynthesis, we evaluated the effect of agrochemicals on SL biosynthesis. We found that the diacylhydrazine insect growth regulator, chromafenozide, reduced the endogenous level of 4-deoxyorobanchol (4DO), a major SL in rice. Furthermore, treatment with the same class of insect growth regulator, methoxyfenozide, also resulted in the reduction of 4DO levels in rice root exudates. These results suggest that chromafenozide and methoxyfenozide are novel lead inhibitors of SL biosynthesis.  相似文献