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81.
Structural complexes in the squid giant axon membrane sensitive to ionic concentrations and cardiac glycosides 下载免费PDF全文
Giant nerve fibers of squid Sepioteuthis sepioidea were incubated for 10 min in artificial sea water (ASW) under control conditions, in the absence of various ions, and in the presence of cardiac glycosides. The nerve fibers were fixed in OsO4 and embedded in Epon, and structural complexes along the axolemma were studied. 相似文献
82.
Christopher J. Danpure Graeme M. Birdsey Gillian Rumsby Michael J. Lumb P. Edward Purdue Jennifer Allsop 《Human genetics》1994,94(1):55-64
The autosomal recessive disease primary hyperoxaluria type 1 (PH1) is caused by a deficiency of the liver-specific peroxisomal enzyme alanine:glyoxylate aminotransferase (AGT). This paper concerns the identification, characterization and clinical use of an unusual discretely polymorphic tandem repeat sequence in the fourth intron of the human AGT gene (gene locus designation AGXT). In a random Caucasian population, three alleles could be clearly recognized that consisted of either 12 (type III), 17 (type 11) or 38 (type I) tandemly repeated copies of a highly conserved 29/32-bp sequence with frequencies of 33%, 7% and 60%, respectively. In a random Japanese population, the allelic frequencies were markedly different (i.e. 31%, 45% and 19%, respectively). In addition, a fourth allele was identified, consisting of 32 repeats (type IV), with an allelic frequency of 5% in Japanese. The repetitive sequence was similar to previously identified mammalian sequences with homology to the Epstein-Barr virus IR3 repetitive element involving a 12/15-bp region GCA(GGN)GGAGGAGGG within the repeat unit. This IR3-like sequence was interspersed with a 17-bp sequence with no similarity to any currently known repetitive element. The type I and type III alleles were judged to be equivalent to a previously identifiedTagI polymorphism. Two polymorphisms previously shown to be associated with the peroxisome-to-mitochondrion mistargeting of AGT in PHI (a C154T point substitution in exon 1 and a 74-bp duplication in intron 1) were found to segregate exclusively with the type I intron 4 polymorphism in Caucasians, but not in Japanese. The polymorphic nature of the intron 4 tandem repeats makes them of potential use in the prenatal diagnosis of PH1, especially when coupled with the exon 1 C154T substitution or intron 1 duplication polymorphisms. A PH1 family, in which a fetus had been predicted previously to be either normal or a carrier by AGT enzymic analysis of a fetal liver biopsy, but who had been shown to be only partially informative with respect to the C154T/intron 1 polymorphisms, was analysed retrospectively. The family was completely informative for the intron 4 tandem repeat polymorphism and the carrier status of the fetus was confirmed. 相似文献
83.
Anne-Ga?lle Biacabe Jorg G Jacobs Anna Bencsik Jan PM Langeveld Thierry GM Baron 《朊病毒》2007,1(1):61-68
We previously reported that some cattle affected by bovine spongiform encephalopathy (BSE) showed distinct molecular features of the protease-resistant prion protein (PrPres) in Western blot, with a 1–2 kDa higher apparent molecular mass of the unglycosylated PrPres associated with labelling by antibodies against the 86–107 region of the bovine PrP protein (H-type BSE). By Western blot analyses of PrPres, we now showed that the essential features initially described in cattle were observed with a panel of different antibodies and were maintained after transmission of the disease in C57Bl/6 mice. In addition, antibodies against the C-terminal region of PrP revealed a second, more C-terminally cleaved, form of PrPres (PrPres #2), which, in unglycosylated form, migrated as a ≈ 14 kDa fragment. Furthermore, a PrPres fragment of ≈7 kDa, which was not labelled by C-terminus-specific antibodies and was thus presumed to be a product of cleavage at both N- and C-terminal sides of PrP protein, was also detected. Both PrPres #2 and ≈7 kDa PrPres were detected in cattle and in C57Bl/6 infected mice. These complex molecular features are reminiscent of findings reported in human prion diseases. This raises questions regarding the respective origins and pathogenic mechanisms in prion diseases of animals and humans.Key Words: prion, BSE, Creutzfeldt-Jakob, Gerstmann-Sträussler-Scheinker, Western blot, amyloid 相似文献
84.
Gibson S Kibiki Bert Mulder Wil MV Dolmans Jessica L de Beer Martin Boeree Noel Sam Dick van Soolingen Christophe Sola Adri GM van der Zanden 《BMC microbiology》2007,7(1):51
Background
Tuberculosis (TB) is a major health problem and HIV is the major cause of the increase in TB. Sub-Saharan Africa is endemic for both TB and HIV infection. Determination of the prevalence of M. tuberculosis strains and their drug susceptibility is important for TB control. 相似文献85.
Giulio Galla Gianni Barcaccia Angelo Ramina Silvio Collani Fiammetta Alagna Luciana Baldoni Nicolò GM Cultrera Federico Martinelli Luca Sebastiani Pietro Tonutti 《BMC plant biology》2009,9(1):128-17
Background
Olea europaea L. is a traditional tree crop of the Mediterranean basin with a worldwide economical high impact. Differently from other fruit tree species, little is known about the physiological and molecular basis of the olive fruit development and a few sequences of genes and gene products are available for olive in public databases. This study deals with the identification of large sets of differentially expressed genes in developing olive fruits and the subsequent computational annotation by means of different software. 相似文献86.
Fish populations in Albasini and Nandoni dams are negatively affected by extensive netting practices. This observation was made by the authors following a number of fish health assessment surveys related to aquatic pollution in the Luvuvhu River catchment. A comparison between the number and size of fish collected over a period of ten years indicated decreases in the average size and a consistent low number of fish, despite similar extensive sampling efforts. Unregulated netting is a common practice in both dams. This may become a serious problem as fish from these two dams are an important source of protein for the local communities. The purpose of this note is to report that gillnets are illegally used in the system and on the effect this could have on the fish population. The authors suggest educational and awareness initiatives to inform local communities about the importance of utilising fish in a sustainable manner to ensure the livelihood of generations to come. 相似文献
87.
Foliar elemental composition of European forest tree species associated with evolutionary traits and present environmental and competitive conditions 下载免费PDF全文
88.
Esther Reefman Marcelus CJM de Jong Hilde Kuiper Marcel F Jonkman Pieter C Limburg Cees GM Kallenberg Marc Bijl 《Arthritis research & therapy》2007,8(6):R156
Apoptotic cells are thought to play an essential role in the pathogenesis of systemic lupus erythematosus (SLE). We hypothesise
that delayed or altered clearance of apoptotic cells after UV irradiation will lead to inflammation in the skin of SLE patients.
Fifteen SLE patients and 13 controls were irradiated with two minimal erythemal doses (MEDs) of ultraviolet B light (UVB).
Subsequently, skin biopsies were analysed (immuno)histologically, over 10 days, for numbers of apoptotic cells, T cells, macrophages,
and deposition of immunoglobulin and complement. Additionally, to compare results with cutaneous lesions of SLE patients,
20 biopsies of lupus erythematosus (LE) skin lesions were analysed morphologically for apoptotic cells and infiltrate. Clearance
rate of apoptotic cells after irradiation did not differ between patients and controls. Influx of macrophages in dermal and
epidermal layers was significantly increased in patients compared with controls. Five out of 15 patients developed a dermal
infiltrate that was associated with increased epidermal influx of T cells and macrophages but not with numbers of apoptotic
cells or epidermal deposition of immunoglobulins. Macrophages were ingesting multiple apoptotic bodies. Inflammatory lesions
in these patients were localised near accumulations of apoptotic keratinocytes similar as was seen in the majority of LE skin
lesions. In vivo clearance rate of apoptotic cells is comparable between SLE patients and controls. However, the presence of inflammatory
lesions in the vicinity of apoptotic cells, as observed both in UVB-induced and in LE skin lesions in SLE patients, suggests
that these lesions result from an inflammatory clearance of apoptotic cells. 相似文献
89.
Background
Experimental populations of Escherichia coli have evolved for 20,000 generations in a uniform environment. Their rate of improvement, as measured in competitions with the ancestor in that environment, has declined substantially over this period. This deceleration has been interpreted as the bacteria approaching a peak or plateau in a fitness landscape. Alternatively, this deceleration might be caused by non-transitive competitive interactions, in particular such that the measured advantage of later genotypes relative to earlier ones would be greater if they competed directly. 相似文献90.
Fungal hydrogenosomes contain mitochondrial heat-shock proteins 总被引:3,自引:0,他引:3
van der Giezen M Birdsey GM Horner DS Lucocq J Dyal PL Benchimol M Danpure CJ Embley TM 《Molecular biology and evolution》2003,20(7):1051-1061
At least three groups of anaerobic eukaryotes lack mitochondria and instead contain hydrogenosomes, peculiar organelles that make energy and excrete hydrogen. Published data indicate that ciliate and trichomonad hydrogenosomes share common ancestry with mitochondria, but the evolutionary origins of fungal hydrogenosomes have been controversial. We have now isolated full-length genes for heat shock proteins 60 and 70 from the anaerobic fungus Neocallimastix patriciarum, which phylogenetic analyses reveal share common ancestry with mitochondrial orthologues. In aerobic organisms these proteins function in mitochondrial import and protein folding. Homologous antibodies demonstrated the localization of both proteins to fungal hydrogenosomes. Moreover, both sequences contain amino-terminal extensions that in heterologous targeting experiments were shown to be necessary and sufficient to locate both proteins and green fluorescent protein to the mitochondria of mammalian cells. This finding, that fungal hydrogenosomes use mitochondrial targeting signals to import two proteins of mitochondrial ancestry that play key roles in aerobic mitochondria, provides further strong evidence that the fungal organelle is also of mitochondrial ancestry. The extraordinary capacity of eukaryotes to repeatedly evolve hydrogen-producing organelles apparently reflects a general ability to modify the biochemistry of the mitochondrial compartment. 相似文献