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1.
DNA content of free living rhizobia and bacteroids of various Rhizobium-legume associations 总被引:1,自引:0,他引:1
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The DNA content of bacteroids from 22 different Rhizobium-legume associations was compared to that of the corresponding free living Rhizobium species using laser flow microfluorometry. In all 18 effective associations, the bacteroids had either similar or higher DNA content than the free living rhizobia. Bacteroid populations isolated from effective clover (Trifolium repens) and alfalfa (Medicago sativa) nodules had an average DNA content of >1.5-fold higher than free living R. trifolii and R. meliloti. These populations also contained a significant number of bacteroids with more than 3-fold the DNA content of the free living rhizobia. Populations isolated from effective nodules of winged beans (Psophocarpus tetragonolobus), peas (Pisum sativum), and mung beans (Phaseolus aureus) had an average DNA content of 1.1- to 1.5-fold higher than free living R. “cowpeas” and R. leguminosarum. Bacteroids from nodules of lupins (Lupinus angustifolius and L. minaretta), kidney beans (Phaseolus vulgaris), and soybeans (Glycine max), however, had similar DNA content to the free living forms. Two of the four associations which formed ineffective nodules contained bacteroids with lower DNA content than the free living rhizobia. The other two associations contained bacteroids with slightly higher or similar DNA content to the free living rhizobia. Nodules of the ineffective associations also did not contain leghemoglobin. 相似文献
2.
The applicability of flow-microfluorometry (FMF) to the study of bacterial samples was investigated on cultures of Rhizobium meliloti, Rhizobium japonicum, and Escherichia coli using fluorescent and light-scattering signals. This technique which analyzes individual bacterial cells in a population was used to monitor the relative change in nucleic acid content and cell size during the growth cycle of the three microorganisms which were known to have different growth rates. Early log-phase E. coli cells contained at least eightfold more nucleic acid and were significantly larger than the stationary-phase cells. Cultures of early log-phase R. meliloti cells contained three to four-fold more nucleic acid and were slightly larger than cells in the stationary phase. Rhizobium japonicum had very little change in either parameter. In general, the amount of change in both cell size and nucleic acid content upon initiation of log-phase growth was related to the overall growt rate of the organisms, with E. coli experiencing the greatest change and R. japonicum the least. Results obtained by FMF analysis, therefore, were consistent with observations reported by earlier workers. Cultures of R. meliloti also were used to demonstrate that the intensity of the fluorescent signals was sensitive to digestion by DNase and RNase and to prolonged storage and fixation. The potential use of FMF in the study of microorganisms is discussed. 相似文献
3.
van Beers JJ Raijmakers R Alexander LE Stammen-Vogelzangs J Lokate AM Heck AJ Schasfoort RB Pruijn GJ 《Arthritis research & therapy》2010,12(6):R219
Introduction
Rheumatoid arthritis (RA) frequently involves the loss of tolerance to citrullinated antigens, which may play a role in pathogenicity. Citrullinated fibrinogen is commonly found in inflamed synovial tissue and is a frequent target of autoantibodies in RA patients. To obtain insight into the B-cell response to citrullinated fibrinogen in RA, its autoepitopes were systematically mapped using a new methodology. 相似文献4.
Separation of algal mixtures and bacterial mixtures with flow-microfluorometer using chlorophyll and ethidium bromide fluorescence 总被引:4,自引:0,他引:4
A. S. Paau J. R. Cowles J. Oro A. Bartel E. Hungerford 《Archives of microbiology》1979,120(3):271-273
The applicability of flow-microfluorometer to separate microbial cells was demonstrated with algal and bacterial cells. Algal mixtures were sorted according to the natural chlorophyll fluorescence and the bacterial mixtures were sorted according to the fluorescence of ethidium bromide-stained nucleic acid.Abbreviation FMF
Flow-microfluorometer 相似文献
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Andréia S Lessa Bruno D Paredes Juliana V Dias Adriana B Carvalho Luiz Fernando Quintanilha Christina M Takiya Bernardo R Tura Guilherme FM Rezende Antonio C Campos de Carvalho Célia MC Resende Regina CS Goldenberg 《BMC veterinary research》2010,6(1):1-10
Background
Atypical scrapie was first identified in Norwegian sheep in 1998 and has subsequently been identified in many countries. Retrospective studies have identified cases predating the initial identification of this form of scrapie, and epidemiological studies have indicated that it does not conform to the behaviour of an infectious disease, giving rise to the hypothesis that it represents spontaneous disease. However, atypical scrapie isolates have been shown to be infectious experimentally, through intracerebral inoculation in transgenic mice and sheep. The first successful challenge of a sheep with 'field' atypical scrapie from an homologous donor sheep was reported in 2007.Results
This study demonstrates that atypical scrapie has distinct clinical, pathological and biochemical characteristics which are maintained on transmission and sub-passage, and which are distinct from other strains of transmissible spongiform encephalopathies in the same host genotype.Conclusions
Atypical scrapie is consistently transmissible within AHQ homozygous sheep, and the disease phenotype is preserved on sub-passage. 相似文献8.
Patterns of Root Colonization in Epacridaceous Plants Collected from Different Sites 总被引:2,自引:0,他引:2
Root colonization was studied in ten species of the Epacridaceaeat three sites in Victoria by morphological and cross-inoculationexperiments. The sites and genera chosen were Cranbourne [Epacrisimpressa Labill. andLeucopogon ericoides(Smith) R. Br.] andRye [L. parviflorus(Andrews) Lindley] on the Mornington Peninsula,and the Grampians[Astroloma conostephioides(Sond.) Benth.,A.humifusum(Cav.) R. Br.,A pinifolium(R. Br.) Benth,Brachylomadaphnoides(Smith) Benth.,E. impressa, E. impressavar.grandifloraBenth.andStyphelia adscendensR. Br.] in western Victoria. For morphologicalstudies, samples of roots from each species at each site werecleared and stained and examined microscopically. For cross-inoculationstudies, cuttings from each site were struck in potting mediuminoculated with soil from the same and other sites. The ericoidmycorrhizae in the roots of plants found at or grown in Cranbourneand Rye soils were similar. Both were significantly differentfrom the internal hyphae found in the roots of plants foundat or grown in Grampians soils, which were three times largerin diameter and formed dense coils which filled the host celland invaded adjacent epidermal cells. This suggests that morethan one fungus is involved in the relationships, that the MorningtonPeninsula sites had a different fungus from the Grampians siteand that host specificity is low. Vesicular structures werealso found commonly on plants at the Grampians site, in contrastwith other sites. Epacridaceae; root; fungus; mycorrhiza; morphology; inoculation 相似文献
9.
Sidders B Withers M Kendall SL Bacon J Waddell SJ Hinds J Golby P Movahedzadeh F Cox RA Frita R Ten Bokum AM Wernisch L Stoker NG 《Genome biology》2007,8(12):R265-13
We describe an analysis, applicable to any spotted microarray dataset produced using genomic DNA as a reference, that quantifies prokaryotic levels of mRNA on a genome-wide scale. Applying this to Mycobacterium tuberculosis, we validate the technique, show a correlation between level of expression and biological importance, define the complement of invariant genes and analyze absolute levels of expression by functional class to develop ways of understanding an organism's biology without comparison to another growth condition. 相似文献
10.
José MC Ribeiro Bruno Arcà Fabrizio Lombardo Eric Calvo My Van Phan Prafulla K Chandra Stephen K Wikel 《BMC genomics》2007,8(1):1-27