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1.
Somatic and flagellar immunofluorescence of Salmonella   总被引:5,自引:0,他引:5  
Caldwell, W. J. (The Child Research Center of Michigan, Detroit, Mich.), C. S. Stulberg, and W. D. Peterson, Jr. Somatic and flagellar immunofluorescence of Salmonella. J. Bacteriol. 92:1177-1187. 1966.-Labeled globulin fractions of flagellar (H) antisera, prepared against 20 frequently occurring Salmonella serotypes belonging to five major somatic (O) groups, were characterized for O and H immunofluorescence and for O and H agglutinin titers against 32 serotypes. The feasibility of immunofluorescent identification of both somatic and flagellar antigens was enhanced by staining formaldehyde-treated organisms in suspension. Relationships between homologous, partial, and unrelated antigen-antibody systems were then analyzed, and a high degree of correlation was shown between the results obtained by the two serological procedures. Flagellar staining was highly specific, and was bright, faint, or inapparent, depending on the relationship between the antigen-antibody systems involved. Somatic staining was also specific, but somewhat more difficult to interpret, because cells in the same preparation might exhibit a mixture of bright, faint, or no fluorescent intensities. Correlation was shown between the percentage of brightly staining cells found in these preparations and the agglutination titers of the comparable antigen-antibody systems. The phenomenon of a "percentage" reaction was unexplained. Absorption studies further confirmed the specificity of reactions. The techniques developed were applied to surveillance of several mouse colonies for the presence of Salmonella. Broth cultures of fecal specimens were treated with formaldehyde and stained in suspension with "polyvalent" labeled antibody reagents. Agreement was found in 97.6% of the instances between results obtained by immunofluorescence and cultural methods. In addition, preliminary evidence indicated the feasibility of presumptive serotyping of Salmonella isolates by immunofluorescence.  相似文献   

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Abstract

The Arctic is a vast, forbidding and relatively unknown region. It covers about 14 million square kilometers of which 5.2 square kilometers is ice covered in summer and 11.7 million square kilometers in winter. It is a highly strategic region, and is the shortest distance between the two superpowers. It also contains vast resources, including oil, gas, and coal. Over 830,000 native peoples inhabit the Arctic Rim and have a culture that goes back 4500 years. The United Nations Convention on the Law of the Sea is generally applicable to the Arctic Ocean and has a special provision for ice‐covered areas. However, there are several unresolved jurisdictional and navigational problems between the United States and other Arctic Rim States concerning the Arctic's waters, including the Chukchi Sea, the Beaufort Sea and the Northwest Passage. Although the United States has paid some attention to the Arctic region in recent years, the Arctic still remains a relatively low priority interest for national policy and operational programs.  相似文献   

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《CMAJ》1941,44(3):307-308
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Several quantitative trait loci (QTLs) that influence developmental dyslexia (reading disability [RD]) have been mapped to chromosome regions by linkage analysis. The most consistently replicated area of linkage is on chromosome 6p23-21.3. We used association analysis in 223 siblings from the United Kingdom to identify an underlying QTL on 6p22.2. Our association study implicates a 77-kb region spanning the gene TTRAP and the first four exons of the neighboring uncharacterized gene KIAA0319. The region of association is also directly upstream of a third gene, THEM2. We found evidence of these associations in a second sample of siblings from the United Kingdom, as well as in an independent sample of twin-based sibships from Colorado. One main RD risk haplotype that has a frequency of approximately 12% was found in both the U.K. and U.S. samples. The haplotype is not distinguished by any protein-coding polymorphisms, and, therefore, the functional variation may relate to gene expression. The QTL influences a broad range of reading-related cognitive abilities but has no significant impact on general cognitive performance in these samples. In addition, the QTL effect may be largely limited to the severe range of reading disability.  相似文献   

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The phytochemical content of the Mediterranean species of the Sideritis genus has been reviewed. The components included in this review are monoterpenes, sesquiterpenes, diterpenes, triterpenes, sterols, flavones, coumarins and phenylpropanoids. From the chemotaxonomic point of view, we have divided the species from this region into four groups. The first of this is formed by taxa containing triterpenes, but not diterpenes. A second group is constituted by species having bicyclic diterpenes of the labdane type and not diterpenes. The third group is characterized by its content in tetracyclic diterpenes of the ent-kaurene type. A fourth group is composed of plants with tetracyclic diterpenes of the ent-beyer-15-ene and/or ent-atis-13-ene class. In addition, the relations of these Mediterranean species with those of the Macaronesian region have been examined.  相似文献   

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段杉  彭志英 《生物技术》2005,15(6):24-27
目的:得到纯化的无花果沙雷氏菌CH02503的壳聚糖酶,并研究其生化性质。方法:将发酵粗酶液先后通过硫酸铵分级沉淀,superdex75凝胶柱和羧甲基纤维素离子交换柱层析,壳聚糖酶得到纯化。结果:经测定,该酶为内切酶,其相对分子质量为29kDa,等电点9.4,在45℃和pH4.0—7.5之间稳定,最适温度是45%,最适pH3.6,Mn^2+、Co^2+能够激活,Pb^2+、Cu^2+、Ni^2+、Cr^3+能够抑制该酶的活性,该酶最适底物是脱乙酰度85%的壳聚糖,对脱乙酰度低于45%的壳聚糖不能作用,对羧甲基甲壳素和羧甲基纤维素不能作用,以完全脱乙酰的壳聚糖为底物时,最终水解产物是单糖、二糖、三糖,反应的米氏常数为0.44mg/ml。  相似文献   

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A collection of petrified wood from the Lower Pliocene Ogallala Formation in western Oklahoma was examined. All specimens appear to be of the same taxon and exhibit features of extant Robinia species. To date, four fossil wood species of Robinia have been described. The relationship of Robinioxylon zuriensis Falqui to Robinia is doubtful because of the lack of diagnostic critical features. The remaining three, Robinia alexanderi Webber, Robinia breweri Prakash, Barghoorn and Scott, and Robinioxylon zirkelii (Platen) Müller-Stoll and Mädel do show affinity to Robinia and all have been noted as structurally similar to R. pseudoacacia. The Oklahoma woods and these three fossil species show considerable overlap in quantitative features and are identical in qualitative features. Examination of different sections (and specimens) of extant Robinia pseudoacacia wood reveals quantitative and qualitative variation similar to that found amongst the petrified woods. Robinia alexanderi, Webber, R. breweri Prakash, Barghoorn and Scott, R. zirkelii (Platen) Müller-Stoll and Mädel, and the Oklahoma specimens are considered to be conspecific as the differences between these fossil wood species are no different from those accounted for by variation within a single living species, R. pseudoacacia.  相似文献   

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Abstract: Growing industrial interest in products from renewable alternative feedstocks has resulted in the creation of more industry-led federal research and development programs. The basis of this interest is introduced, followed by an overview of the various federal programs that support basic through applied research relevant to chemical products from renewable resources, and evidence of the increased coordination efforts between programs. The majority of the paper outlines a new program within the U.S. Department of Energy, the Alternative Feedstocks Program, which specifically targets chemicals from renewables which have the potential to become part of the next generation of high-volume chemical feedstocks for the manufacturing industries. The first product of the program, an iterative process technology decision analysis tool, is broadly presented using the first process development project: succinic acid from fermentable sugars.  相似文献   

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The chemical composition of propolis from Bulgaria, Turkey, Greece and Algeria was investigated by GC-MS. All of them contained mainly flavonoids and esters of caffeic and ferulic acids, which indicated that their main source are buds of poplars of the taxonomic section Aegieros. Some Turkish samples contained a low percent of diterpenic acids, while in Algerian samples significant amounts of a hydroxyditerpenic acid (M=322, its structure not determined by its MS) were found. All samples showed significant antibacterial and weak to moderate antifungal activity.  相似文献   

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Prevalence of Toxoplasma gondii infection in chickens is a good indicator of the strains prevalent in their environment because they feed from ground. The prevalence of T. gondii was determined in 118 free-range chickens from 14 counties in Ohio and in 11 chickens from a pig farm in Massachusetts. Toxoplasma gondii antibodies (> or = 1: 5) were found using the modified agglutination test (MAT) in 20 of 118 chickens from Ohio. Viable T. gondii was recovered from 11 of 20 seropositive chickens by bioassay of their hearts and brains into mice. The parasite was not isolated from tissues of 63 seronegative (< or = 1:5) chickens by bioassay in cats. Hearts, brains, and muscles from legs and breast of the 11 chickens from the pig farm in Massachusetts were fed each to a T. gondii-negative cat. Eight cats fed chicken tissues shed oocysts; the 3 cats that did not shed oocysts were fed tissues of chickens with MAT titers of 1:5 or less. Tachyzoites of 19 isolates of T. gondii from Ohio and Massachusetts were considered avirulent for mice. Of 19 isolates genotyped, 5 isolates were type II and 14 were type III; mixed types and type I isolates were not found.  相似文献   

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中美《农业生态学》教材的比较分析   总被引:1,自引:0,他引:1  
为了了解《农业生态学》教学的发展趋势,对近30年美国和中国多个作者多个版本的《农业生态学》教材进行了分析。教材的共同特点是:都针对工业化农业存在不可持续的问题提出了农业发展的新构想;都把农业生态学的理论框架定位在农业生态系统层面;提倡农业的新发展方向时都注重能够协调农业社会效益、经济效益和生态效益的工业化农业替代方法。教材的不同特点表现在:在教材引用的典型和例证方面,美国教材除了本国的例子外,比较经常运用多国获得的一手素材,也比较多运用自身研究的结果,个性表现强,中国的教材比较多局限在本国的典型实践经验方面,自身研究成果不够丰富;中国的教材有更加严密和稳定的理论框架和逻辑体系,美国教材的体系变化还比较多。教材的发展方向都表现在:注意平衡生态学基础与农业实践两个部分的教学内容;引入更多的实践方法与丰富的研究成果;教材内容注重了农业可持续发展的社会组织层面;注意通过实验与实习强化学生的动手能力;开始重视视听和网络资源的利用。文章还分析了形成这些特点的原因。  相似文献   

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Due to the increasing prevalence of Dinophysis spp. and their toxins on every US coast in recent years, the need to identify and monitor for problematic Dinophysis populations has become apparent. Here, we present morphological analyses, using light and scanning electron microscopy, and rDNA sequence analysis, using a ~2-kb sequence of ribosomal ITS1, 5.8S, ITS2, and LSU DNA, of Dinophysis collected in mid-Atlantic estuarine and coastal waters from Virginia to New Jersey to better characterize local populations. In addition, we analyzed for diarrhetic shellfish poisoning (DSP) toxins in water and shellfish samples collected during blooms using liquid-chromatography tandem mass spectrometry and an in vitro protein phosphatase inhibition assay and compared this data to a toxin profile generated from a mid-Atlantic Dinophysis culture. Three distinct morphospecies were documented in mid-Atlantic surface waters: D. acuminata, D. norvegica, and a “small Dinophysis sp.” that was morphologically distinct based on multivariate analysis of morphometric data but was genetically consistent with D. acuminata. While mid-Atlantic D. acuminata could not be distinguished from the other species in the D. acuminata-complex (D. ovum from the Gulf of Mexico and D. sacculus from the western Mediterranean Sea) using the molecular markers chosen, it could be distinguished based on morphometrics. Okadaic acid, dinophysistoxin 1, and pectenotoxin 2 were found in filtered water and shellfish samples during Dinophysis blooms in the mid-Atlantic region, as well as in a locally isolated D. acuminata culture. However, DSP toxins exceeded regulatory guidance concentrations only a few times during the study period and only in noncommercial shellfish samples.  相似文献   

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