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81.
Immunological similarities between specific chloroplast ribosomal proteins from Chlamydomonas reinhardtii and ribosomal proteins from Escherichia coli 总被引:11,自引:0,他引:11
Polyclonal antibodies were elicited against seven of the 33 different
proteins of the large subunit of the chloroplast ribosome from
Chlamydomonas reinhardtii. Three of these proteins are synthesized in the
chloroplast and four are made in the cytoplasm and imported. In western
blots, six of the seven antisera are monospecific for their respective
large subunit ribosomal proteins, and none of these antisera cross-reacted
with any chloroplast small subunit proteins from C. reinhardtii. Antisera
to the three chloroplast-synthesized ribosomal proteins cross-reacted with
specific Escherichia coli large subunit proteins of comparable charge and
molecular weight. Only one of the four antisera to the chloroplast
ribosomal proteins synthesized in the cytoplasm cross-reacted with an E.
coli large subunit protein. None of the antisera cross-reacted with any E.
coli small subunit proteins. On the assumption of a procaryotic,
endosymbiotic origin for the chloroplast, those chloroplast ribosomal
proteins still synthesized within the organelle appear to have retained
more antigenic sites in common with E. coli ribosomal proteins than have
those which are now the products of cytoplasmic protein synthesis. Antisera
to this cytoplasmically synthesized group of chloroplast ribosomal proteins
did not recognize any antigenic sites among C. reinhardtii cytoplasmic
ribosomal proteins, suggesting that the genes for the cytoplasmically
synthesized chloroplast ribosomal proteins either are not derived from the
cytoplasmic ribosomal protein genes or have evolved to a point where no
antigenic similarities remain.
相似文献
82.
M D Lee G E Quinton R E Beeman A A Biehle R L Liddle D E Ellis RJ Buchanan Jr 《Journal of industrial microbiology & biotechnology》1997,18(2-3):106-115
For the full scale implementation of in situ anaerobic bioremediation of tetrachloroethene (PCE) in groundwater, the following issues must be addressed: which organic
substrates at which concentration would be most effective in promoting dechlorination and are economical; how far the substrate,
electron acceptor, and nutrients can be transported in the aquifer; and the placement of delivery and recovery wells for
distributing these amendments. In a microcosm study, almost all of the tested inexpensive substrates supported reductive
dechlorination of PCE through vinyl chloride (VC) under methanogenic conditions. A minimum of about 60 mg L−1 of organic carbon was needed to dechlorinate 23 μM PCE with a single feeding. In a second microcosm study dechlorination
stopped at 1,2-dichloroethene (DCE) in microcosms fed higher concentrations of several substrates. At the highest concentrations
the substrates inhibited DCE production. Three field tracer tests were conducted to evaluate methods to distribute the amendments
across the aquifer. The natural groundwater gradient is not sufficient to distribute substrate evenly. Groundwater injection
at 60 times the natural flux rate increased the distribution of substrate. A mixing strategy of cross-gradient injection
further increased the distribution of the substrate. Ammonia-nitrogen, sulfate, and phosphate were retarded relative to
the substrate and inorganic tracer.
Received 30 October 1995/ Accepted in revised form 07 June 1996 相似文献
83.
Immunohistochemistry (IHC) is used to detect antibody-specific antigens in tissues; the results depend on the ability of the primary antibodies to bind to their antigens. Therefore, results depend on the quality of preservation of the specimen. Many investigators have overcome the deleterious effects of over-fixation on the binding of primary antibodies to specimen antigens using IHC, but if the specimen is under-fixed or fixation is delayed, false negative results could be obtained despite certified laboratory practices. Microtubule-associated protein 2 (MAP2) is an abundant microtubule-associate protein that participates in the outgrowth of neuronal processes and synaptic plasticity; it is localized primarily in cell bodies and dendrites of neurons. MAP2 immunolabeling has been reported to be absent in areas of the entorhinal cortex and hippocampus of Alzheimer’s disease brains that were co-localized with the dense-core type of amyloid plaques. It was hypothesized that the lack of MAP2 immunolabeling in these structures was due to the degradation of the MAP2 antigen by the neuronal proteases that were released as the neurons lysed leading to the formation of these plaques. Because MAP2 is sensitive to proteolysis, we hypothesized that changes in MAP2 immunolabeling may be correlated with the degree of fixation of central nervous system (CNS) tissues. We detected normal MAP2 immunolabeling in fixed rat brain tissues, but MAP2 immunolabeling was decreased or lost in unfixed and delayed-fixed rat brain tissues. By contrast, two ubiquitous CNS-specific markers, myelin basic protein and glial fibrillary acidic protein, were unaffected by the degree of fixation in the same tissues. Our observations suggest that preservation of various CNS-specific antigens differs with the degree of fixation and that the lack of MAP2 immunolabeling in the rat brain may indicate inadequate tissue fixation. We recommend applying MAP2 IHC for all CNS tissues as a pre-screen to assess the quality of the tissue preservation and to avoid potentially false negative IHC results. 相似文献
84.
85.
Matthew N Ward Allison M Churcher Kevin J Dick Chris RJ Laver Greg L Owens Megan D Polack Pam R Ward Felix Breden John S Taylor 《BMC evolutionary biology》2008,8(1):210
Background
Comparisons of functionally important changes at the molecular level in model systems have identified key adaptations driving isolation and speciation. In cichlids, for example, long wavelength-sensitive (LWS) opsins appear to play a role in mate choice and male color variation within and among species. To test the hypothesis that the evolution of elaborate coloration in male guppies (Poecilia reticulata) is also associated with opsin gene diversity, we sequenced long wavelength-sensitive (LWS) opsin genes in six species of the family Poeciliidae. 相似文献86.
Changes in genetic structure of North American Bythotrephes populations following invasion from Lake Ladoga, Russia 总被引:3,自引:0,他引:3
David J. Berg David W. Garton Hugh J. Macisaac Vadim E. Panov & Irena V. Telesh 《Freshwater Biology》2002,47(2):275-282
1. We used allozyme electrophoresis to compare Bythotrephes longimanus (Crustacea: Onychopoda: Cercopagididae) from recently founded North American populations with those from native European populations, and to examine changes in genetic structure of North American populations over time.
2. The genetic structure of North American populations in 1996 was similar to that of European populations, because of the disappearance of founder effects which distinguished North American from European populations in 1989.
3. The Lake Ladoga, Russia population was more closely related to North American populations than to other European populations, consistent with non-genetic evidence implicating Lake Ladoga as the source of North American populations.
4. Our results provide additional evidence of the presence of an invasion corridor that allows Urasian and Ponto-Caspian species to be introduced into North American freshwater ecosystems, and show that founder effects can erode over time following establishment of invasive species. 相似文献
2. The genetic structure of North American populations in 1996 was similar to that of European populations, because of the disappearance of founder effects which distinguished North American from European populations in 1989.
3. The Lake Ladoga, Russia population was more closely related to North American populations than to other European populations, consistent with non-genetic evidence implicating Lake Ladoga as the source of North American populations.
4. Our results provide additional evidence of the presence of an invasion corridor that allows Urasian and Ponto-Caspian species to be introduced into North American freshwater ecosystems, and show that founder effects can erode over time following establishment of invasive species. 相似文献
87.
88.
Laser photocoagulation induced choroidal neovascularization currently is the most effective model available for the study of this disease in terms of efficacy of new drugs and therapies. Previously, evaluating the extent of choroidal neovascularization using this model was time- consuming and required the use of experienced personnel. We describe a new method for simple and rapid evaluation of laser induced choroidal neovascularization using densitometry. Fluorescein angiograms of a laser photocoagulated rat eye were scanned into a computer. Densitometry software subsequently was used to calculate the severity of the laser lesions. The densitometry method proved effective for calculating the extent of laser induced choroidal neovascularization. In addition, this method was more rapid than visual evaluations and less likely to produce errors. 相似文献
89.
Alien fishes are considered a major threat to aquatic biodiversity in South Africa, yet relatively little regional information on their biology and ecology is available for many of these species. Seasonal changes in the diet of the bluegill Lepomis macrochirus in Howieson’s Poort Dam, Grahamstown, were assessed during summer and winter in 2014–2015, using stomach content analysis. In winter, juvenile and adult fish diets were dominated by crustacean zooplankton and insects, respectively. In summer, juvenile fish fed on crustaceans and insects, whereas adults consumed mostly fish eggs, indicating a potential impact by these invasive fish on native fish through oophagy. 相似文献
90.
Liam D. Cassidy Andrew RJ. Young Pedro A. Pérez-Mancera Birgit Nimmervoll Adil Jaulim Hung-Chang Chen 《Autophagy》2018,14(7):1256-1266
Macroautophagy/autophagy is an evolutionarily conserved catabolic pathway whose modulation has been linked to diverse disease states, including age-associated disorders. Conventional and conditional whole-body knockout mouse models of key autophagy genes display perinatal death and lethal neurotoxicity, respectively, limiting their applications for in vivo studies. Here, we have developed an inducible shRNA mouse model targeting Atg5, allowing us to dynamically inhibit autophagy in vivo, termed ATG5i mice. The lack of brain-associated shRNA expression in this model circumvents the lethal phenotypes associated with complete autophagy knockouts. We show that ATG5i mice recapitulate many of the previously described phenotypes of tissue-specific knockouts. While restoration of autophagy in the liver rescues hepatomegaly and other pathologies associated with autophagy deficiency, this coincides with the development of hepatic fibrosis. These results highlight the need to consider the potential side effects of systemic anti-autophagy therapies. 相似文献