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Ann E. Wakefield Sarah E. Peters Suneale Banerji Paul D. Bridge Geoffrey S. Hall David L. Hawksworth Lynden A. Guiver rew G. Allen Julian M. Hopkin 《Molecular microbiology》1992,6(14):1903-1911
Pneumocystis carinii causes life-threatening pneumonia in T-lymphocyte-immunodeficient subjects in transplant and oncology units or with acquired immune deficiency syndrome (AIDS). Recent DNA homology studies show P. carinii to be a fungus. To investigate the biology and epidemiology of this parasite further, we elected to determine for it a more precise taxonomic assignment within the fungal kingdom. We screened a wide range of organisms representing the major orders of fungi using DNA amplification and subsequently sequenced a portion of the mitochondrial gene encoding the large subunit ribosomal RNA. Our data show that the opportunistic pulmonary pathogen P. carinii is closely related to the ustomycetous red yeast fungi, a group which includes organisms that are extensively distributed throughout the environment and which release many widely dispersed airborne spores. 相似文献
23.
Tom Lanaras Catherine M. Cook Ann P. Wood Don P. Kelly Geoffrey A. Codd 《Archives of microbiology》1991,156(5):338-343
The bacterial symbionts of many marine invertebrates contain ribulose 1,5-bisphosphate (RuBP) carboxylase but apparently no carboxysomes, polyhedral bodies containing RuBP carboxylase. In the few cases where polyhedral bodies have been observed they have not been characterised enzymatically. Polyhedral bodies, 50–90 nm in diameter, were observed in thin cell sections of Thiobacillus thyasiris the putative symbiont of Thyasira flexuosa and RuBP carboxylase activity was detected in both soluble and particulate fractions after centrifugation of cell-free extracts. RuBP carboxylase purified 90-fold from the soluble fraction was of high molecular weight and consisted of large and small subunits, with molecular weights of 53,110 and 11,100 respectively. Particulate RuBP carboxylase activity was associated with polyhedral bodies 50–100 nm in diameter, as revealed by density gradient centrifugation and electron microscopy. Therefore, the polyhedral bodies were inferred to be carboxysomes. Native electrophoresis of isolated carboxysomes demonstrated a major band which comigrated with the purified RuBP carboxylase and three minor bands of lower molecular weight. Sodium dodecyl-sulphate (SDS) gel electrophoresis of SDS-dissociated carboxysomes demonstrated nine major polypeptides two of which were the large and small subunits of RuBP carboxylase. The RuBP carboxylase subunits represented 21% of the total carboxysomal protein. The most abundant polypeptide had a molecular weight of 40,500. Knowledge of carboxysome composition is necessary to provide an understanding of carboxysome function.Abbreviations FPLC
fast performance liquid chromatography
- IB
isolation buffer
- PAGE
polyacrylamide gel electrophoresis
- RuBP
carboxylase
- ribulose
1,5-bisphosphate carboxylase/oxygenase
- SDS
sodium dodecyl-sulphate 相似文献
24.
Body morphology is said to be the all important factor in determining swimming prowess in copepods. Fusion and differentiation of the body (tagmosis) is coupled with advance into the pelagic realm of the Gymnoplea and is thought, by the provision of a rigid thoracic tagma, to promote swimming efficiency. Thus pelagic copepods are believed to be secondarily derived from bottom dwelling predecessors. Experimental evidence is presented to show that the majority of bottom dwelling harpacticoid families, including the most primitive and the most advanced, have representatives that undergo active sustained swimming movements. Such a widespread occurrence is indicative of a conservative evolutionary trait. This primitive behaviour is linked to precopulatory association which takes place necessarily in the water column; it is a feature retained by representatives of all copepod orders. The implication of cephalic appendage vibration (feeding currents) is the essential feature in the swimming success of the Gymnoplea; planktonic efficiency in these is suggested to have evolved coincident with, rather than because of increased tagmosis. 相似文献
25.
Geoffrey K. Rickards 《Chromosoma》1986,94(4):249-252
The position and orientation of an interchange quadrivalent in flattened lateral views of metaphase I were studied in pollen mother cells of hybrid rye. Five quadrivalent types showed three positional distributions in the equator, these distributions having elements both similar to and very different from those found previously for an interchange quadrivalent of Allium triquetrum. 相似文献
26.
Michael Ward Barry Wilkinson Geoffrey Turner 《Molecular & general genetics : MGG》1986,202(2):265-270
Summary An allele (oliC31) of the A. nidulans oliC gene has been cloned using homology with the equivalent gene from N. crassa. OliC31 codes for an oligomycin-resistant, triethyltin-hypersensitive form of subunit 9 of the mitochondrial ATP synthase complex. Direct selection for oligomycin-resistance was possible following transformation of A. nidulans with the oliC31 gene. The phenotypes of transformants cultured in the presence of oligomycin were indicative of the position of integration of the transforming plasmid within the genome. Subsequent recombination events involving the integrated oliC31 gene were also apparent from altered levels of resistance to oligomycin or triethyltin. This gene should prove useful as a marker for transformation of strains lacking auxotrophic lesions and in gene replacement or disruption experiments. 相似文献
27.
28.
Graham J. Boulnois Jennifer M. Varley Geoffrey S. Sharpe F. Christopher H. Franklin 《Molecular & general genetics : MGG》1985,200(1):65-67
Summary The properties of pLG221, a derivative of the ColIb plasmid carrying the transposon Tn5 are described. This plasmid can be used to introduce Tn5 by conjugation from Escherichia coli into a variety of Gram negative bacteria outside the host range for maintenance of ColIb. Plasmid pLG221, and a similar plasmid pLG223 carrying Tn10 may be of general utility as vectors for transposon-mediated mutagenesis in a variety of Gram negative bacteria. 相似文献
29.
Dr. Edilio Borroni Patrizia Ferretti Wolfgang Fiedler Geoffrey Q. Fox 《Cell and tissue research》1985,241(2):367-372
Summary A proteoglycan-specific antiserum has been used to monitor the effects of denervation in the electric organ of Torpedo marmorata. The antiserum was produced by injecting a highly purified synaptic vesicle fraction prepared from the electric organs of Torpedo marmorata. Following absorption the serum appears to be specific towards synaptic vesicles. The ultrastructural localization of the antigen determined by immuno-electron microscopy confirmed the specificity of the antiserum and showed that it did not crossreact with the proteoglycans of the basal lamina. The rate of disappearance of the vesicle proteoglycans following denervation was evaluated by means of the antiserum and was compared to the rate of disappearance of other vesicular and nerve terminal-associated markers. The results suggest that degeneration affects the vesicular constituents at varying rates resulting in a progressive disappearance of the entire functional capacity of the synaptic vesicles. 相似文献
30.