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Nonparametric regression in the presence of measurement error 总被引:4,自引:0,他引:4
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Ponnappan RK Markova DZ Antonio PJ Murray HB Vaccaro AR Shapiro IM Anderson DG Albert TJ Risbud MV 《Arthritis research & therapy》2011,13(5):R171
Introduction
Back pain, a significant source of morbidity in our society, is related to the degenerative changes of the intervertebral disc. At present, the treatment of disc disease consists of therapies that are aimed at symptomatic relief. This shortcoming stems in large part from our lack of understanding of the biochemical and molecular events that drive the disease process. The goal of this study is to develop a model of early disc degeneration using an organ culture. This approach is based on our previous studies that indicate that organ culture closely models molecular events that occur in vivo in an ex vivo setting. 相似文献24.
A characteristic feature of the sperm P1 protamines of eutherian mammals is
the constant presence of six to nine cysteine residues per molecule. During
spermiogenesis these residues become oxidized to form a three-dimensional
network of disulfide bridges between, and within, protamine molecules in
the sperm chromatin. This covalent cross linking strongly stabilizes
eutherian sperm nuclei. In contrast, protamines sequenced from teleost
fish, birds, monotremes, and marsupials all lack cysteine residues and
their sperm nuclei, without the stabilizing cross links, are easily
decondensed in vitro. We have now found that one genus of tiny, shrewlike
dasyurid marsupials, the Planigales, possess P1 protamines containing five
to six cysteine residues. These residues appear to have evolved since the
divergence of Planigales from other members of the family Dasyuridae, such
as the marsupial mouse, Sminthopsis crassicaudata. We believe this
constitutes a case of convergent evolution in a subfamily of dasyurid
marsupials toward the cysteine-rich eutherian form of sperm protamine P1.
相似文献
25.
Rampant horizontal transfer and duplication of rubisco genes in eubacteria and plastids 总被引:14,自引:2,他引:14
Previous work has shown that molecular phylogenies of plastids,
cyanobacteria, and proteobacteria based on the rubisco (ribulose-1,5-
bisphosphate carboxylase/oxygenase) genes rbcL and rbcS are incongruent
with molecular phylogenies based on other genes and are also incompatible
with structural and biochemical information. Although it has been much
speculated that this is the consequence of a single horizontal gene
transfer (of a proteobacterial or mitochondrial rubisco operon into
plastids of rhodophytic and chromophytic algae), neither this hypothesis
nor the alternative hypothesis of ancient gene duplication have been
examined in detail. We have conducted phylogenetic analyses of all
available bacterial rbcL sequences, and representative plastid sequences,
in order to explore these alternative hypothesis and fully examine the
complexity of rubisco gene evolution. The rbcL phylogeny reveals a
surprising number of gene relationships that are fundamentally incongruent
with organismal relationships as inferred from multiple lines of other
molecular evidence. On the order of six horizontal gene transfers are
implied by the form I (L8S8) rbcL phylogeny, two between cyanobacteria and
proteobacteria, one between proteobacteria and plastids, and three within
proteobacteria. Alternatively, a single ancient duplication of the form I
rubisco operon, followed by repeated and pervasive differential loss of one
operon or the other, would account for much of this incongruity. In all
probability, the rubisco operon has undergone multiple events of both
horizontal gene transfer and gene duplication in different lineages.
相似文献
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K Kertesz-Chaloupková PJ Walser JD Granado M Aebi U Kües 《Fungal genetics and biology : FG & B》1998,23(1):95-109
Monokaryotic mycelia of the homobasidiomycete Coprinus cinereus form asexual spores (oidia) constitutively in abundant numbers. Mycelia with mutations in both mating type loci (Amut Bmut homokaryons) also produce copious oidia but only when exposed to blue light. We used such an Amut Bmut homokaryon to define environmental and inherent factors that influence the light-induced oidiation process. We show that the Amut function causes repression of oidiation in the dark and that light overrides this effect. Similarly, compatible genes from different haplotypes of the A mating type locus repress sporulation in the dark and not in the light. Compatible products of the B mating type locus reduce the outcome of light on A-mediated repression but the mutated B function present in the Amut Bmut homokaryons is not effective. In dikaryons, the coordinated regulation of asexual sporulation by compatible A and B mating type genes results in moderate oidia production in light. Copyright 1998 Academic Press. 相似文献
28.
Production and characterization of a monoclonal antibody able to discriminate galectin-1 from galectin-2 and galectin-3 总被引:1,自引:0,他引:1
Cornillot JD; Pontet M; Dupuy C; Chadli A; Caron M; Joubert-Caron R; Bourin P; Bladier D 《Glycobiology》1998,8(5):425-432
Antisera raised against galectin-1 exhibit crossreactivities with other
galectins or related molecules. In order to overcome this problem, a
monoclonal antibody to human brain galectin-1 was obtained by selecting
clones without reactivity toward galectin-3. This mAb specifically bound
galectin-1 of various animal origins but neither galectin-2 nor galectin-3.
Western-blotting analysis of soluble human brain extracts after 2D gel
electrophoresis revealed only the two most acidic isoforms of galectin-1.
The ability of this mAb to bind galectin-1/asialofetuin complexes indicates
that its epitope is not localized in the carbohydrate recognition domain of
galectin-1. This particularity induces with efficiency its monospecificity.
相似文献
29.
An anchored restriction-mapping approach applied to the genetic analysis of the Anopheles gambiae malaria vector complex 1 总被引:1,自引:0,他引:1
We introduce here a simple approach for rapidly determining restriction
maps for a number of regions of a genome; this involves "anchoring" a map
with a rare restriction site (in this case the seldom-cutting EagI)
followed by partial digestion of a frequent-cutting enzyme (e.g., Sau 3A).
We applied this technology to five species of the Anopheles gambiae
complex. In a single Southern blot we obtained about a 15-kb restriction
map each for the mtDNA, rRNA gene, and a scnDNA region for each of five
species. Phylogenetic analyses of these regions yield trees at odds with
the more traditional chromosome inversion-based trees. The value of the
approach for systematic purposes is the ease with which several large,
independent regions of the genome can be quickly assayed for molecular
variation.
相似文献
30.
Borsboom GJ Boatin BA Nagelkerke NJ Agoua H Akpoboua KL Alley EW Bissan Y Renz A Yameogo L Remme JH Habbema JD 《Filaria journal》2003,2(1):8-25
BACKGROUND: The Onchocerciasis Control Program (OCP) in West Africa has been closed down at the end of 2002. All subsequent control will be transferred to the participating countries and will almost entirely be based on periodic mass treatment with ivermectin. This makes the question whether elimination of infection or eradication of onchocerciasis can be achieved using this strategy of critical importance. This study was undertaken to explore this issue. METHODS: An empirical approach was adopted in which a comprehensive analysis was undertaken of available data on the impact of more than a decade of ivermectin treatment on onchocerciasis infection and transmission. Relevant entomological and epidemiological data from 14 river basins in the OCP and one basin in Cameroon were reviewed. Areas were distinguished by frequency of treatment (6-monthly or annually), endemicity level and additional control measures such as vector control. Assessment of results were in terms of epidemiological and entomological parameters, and as a measure of inputs, therapeutic and geographical coverage rates were used. RESULTS: In all of the river basins studied, ivermectin treatment sharply reduced prevalence and intensity of infection. Significant transmission, however, is still ongoing in some basins after 10-12 years of ivermectin treatment. In other basins, transmission may have been interrupted, but this needs to be confirmed by in-depth evaluations. In one mesoendemic basin, where 20 rounds of four-monthly treatment reduced prevalence of infection to levels as low as 2-3%, there was significant recrudescence of infection within a few years after interruption of treatment. CONCLUSIONS: Ivermectin treatment has been very successful in eliminating onchocerciasis as a public health problem. However, the results presented in this paper make it almost certain that repeated ivermectin mass treatment will not lead to the elimination of transmission of onchocerciasis from West Africa. Data on 6-monthly treatments are not sufficient to draw definitive conclusions. 相似文献