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关键词： 微生物分析   肠杆菌科   农产品   试验   微生物学   浓缩   计数   验证   测定   食品   定义  

标准号: NF V08-039-1-2004

摘要： La présente partie de l'ISO 21528 décrit une méthode pour la recherche des Enterobacteriaceae avec préenrichissement. Elle est applicable : - aux produits pour l'alimentation humaine et animale, et - aux échantillons d'environnement pour la production et la distribution des aliments. Le dénombrement est effectué par calcul du nombre le plus probable (NPP) après incubation à 37 oC (ou 30 oC) en milieu liquide. Cette méthode est pertinente : - lorsque les microorganismes recherchés nécessitent une revivification avant enrichissement, et - lorsque le nombre cherché est supposé être compris entre 1 et 100 par millilitre ou par gramme d'échantillon soumis à essai. Des limites sont imposées aux possibilités d'application de la présente partie de l'ISO 21528 du fait que ces méthodes sont sujettes à de grandes variations (voir l'Article 11).

关键词： 动物生产性能   生物学特性   母猪   日粮   无机铬   生物学利用率   微量元素   取出   GTF   巨大  

摘要： 长期以来，微量元素铬被认为是重要的化工原料，因其在印染、制革、冶金行业发挥了巨大作用。然而自从schwartz(1959)首次从啤酒酵母中提取出含有铬的葡萄糖耐量因子并证实Cr^3+是GTF的重要活性成分后，人们才开始认识到铬是动物所必需的微量元素。五十年代末期，美国科学家Bunding在母猪日粮中添加无机铬后，铬制剂在动物生产中的应用才悄然兴起。近年来，随着无机铬源生物学利用率低、毒性强、

关键词： 饲料   微生物分析   试验   微生物学   食品检验   食品试验   抽样方法   食品   验证   使用拭子取标本法   分析  

标准号: NF V08-035-2004

摘要： La présente Norme internationale spécifie des méthodes horizontales pour le prélèvement d'échantillons sur les surfaces se rencontrant dans l'environnement des industries agro-alimentaires (et d'autres transformateurs des produits alimentaires), en vue de rechercher ou de dénombrer des micro-organismes viables.

关键词： BIVALVES   SPAWNING   AQUATIC animals   MARINE biology   MARINE sciences  

摘要： The reproductive behaviour of 248 specimens comprising four size classes of the infaunal bivalve Abra alba ( Wood) was investigated between September 1994 and November 1995 in Kinsale Harbour. Small males returned a very small proportion of sexually mature and spawning animals. By contrast, no spawning females were found in this size class, suggesting that males develop and mature at a smaller size than females. Mean gonad maturity indices indicated that, except for the smallest size class, A. alba exhibits two spawning events in 1 year, i.e. a lesser spring and a major autumn spawning event. The spring event was well synchronised between males and females, while the autumn spawning was more broadly synchronised between the sexes. Only one spawning event was recorded for very large males and females, also occurring in spring. Spawning stages were recorded for both sexes over all size classes between February and November, indicating only a short period of sexual repose, if any. Oocyte diameters did not show a discrete size range from developing to spawning stages. All stages were seen to contain varying proportions of smaller, less mature oocytes, suggesting that large A. alba females do not develop and spawn en bloc, but release their gametes periodically. Maturity indices showed only a broad similarity with off-bottom temperatures.

关键词： 饮食   生物试验   试样制备   微生物分析   定义   饲料   悬浮液   农产品   稀释法   试验室   验证   稀释   微生物学   方法   食品   规范(验收)   微生物   试验  

标准号: BS EN ISO 21567-2004

摘要： This International Standard specifies a horizontal method for the detection of Shigella species. Subject to the limitations discussed in the Introduction, this International Standard is applicable to - products intended for human consumption and the feeding of animals, and - environmental samples in the area of food production and food handling.

关键词： evolutionary novelty   Hox genes   jaw   lamprey   neural crest   pharynx  

摘要： It is generally believed that the jaw arose through the simple transformation of an ancestral rostral gill arch. The gnathostome jaw differentiates from Hox-free crest cells in the mandibular arch, and this is also apparent in the lamprey. The basic Hox code, including the Hox-free default state in the mandibular arch, may have been present in the common ancestor, and jaw patterning appears to have been secondarily constructed in the gnathostomes. The distribution of the cephalic neural crest cells is similar in the early pharyngula of gnathostomes and lampreys, but different cell subsets form the oral apparatus in each group through epithelial-mesenchymal interactions: and this heterotopy is likely to have been an important evolutionary change that permitted jaw differentiation. This theory implies that the premandibular crest cells differentiate into the upper lip, or the dorsal subdivision of the oral apparatus in the lamprey, whereas the equivalent cell population forms the trabecula of the skull base in gnathostomes. Because the gnathostome oral apparatus is derived exclusively from the mandibular arch, the concepts 'oral' and 'mandibular' must be dissociated. The 'lamprey trabecula' develops from mandibular mesoderm, and is not homologous with the gnathostome trabecula, which develops from premandibular crest cells. Thus the jaw evolved as an evolutionary novelty through tissue rearrangements and topographical changes in tissue interactions.

标准号: BS DD CEN ISO/TS 11133-2-2003+A1-2011

关键词： 特性   特性   说明书   实验室规程   术语   微生物分析   质量   制备   培养基   一般条件   饲料   食品   规格试验   生产   质量控制   质量保证   实验室   微生物学  

标准号: BS DD CEN ISO/TS 11133-2-2003

关键词： telomere length   telomerase   oocyte   spermatozoa   embryo   fetus   human   mouse   aging disorders   malformations  

摘要： The development of an organism is a strictly regulated program in which controlled gene expression guarantees the establishment of a specific phenotype. The chromosome termini or so-called telomeres preserve the integrity of the genome within developing cells. In the germline, during early development, and in highly proliferative organs, human telomeres are balanced between shortening processes with each cell division and elongation by telomerase, but once terminally differentiated or mature the equilibrium is shifted to gradual shortening by repression of the telomerase enzyme. Telomere length is to a large extent genetically determined and the neonatal telomere length equilibrium is, in fact, a matter of evolution. Gradual telomere shortening in normal human somatic cells during consecutive rounds of replication eventually leads to critically short telomeres that induce replicative senescence in vitro and probably in vivo. Hence, a molecular clock is set during development, which determines the replicative potential of cells during extrauterine life. Telomeres might be directly or indirectly implicated in longevity determination in vivo, and information on telomere length setting in utero, and beyond should help elucidate presumed causal connections between early growth and aging disorders later in life. Only limited information exists concerning the mechanisms underlying overall telomere length regulation in the germline and during early development, especially in humans. The intent of this review is to focus on recent advances in our understanding of telomere biology in germline cells as well as during development (pre- and postimplantation periods) in an attempt to summarize our knowledge about telomere length determination and its importance for normal development in utero and the occurrence of the aging and abnormal phenotype later on. (C) 2004 Elsevier Inc. All rights reserved.