排序方式: 共有24条查询结果,搜索用时 15 毫秒
11.
Hannah Gardener Della David Morte Mitchell SV Elkind Ralph L Sacco Tatjana Rundek 《BMC cardiovascular disorders》2009,9(1):1-8
Background
Heterogeneity in B-type natriuretic peptide (BNP) levels, especially among individuals with acute heart failure with normal left ventricular ejection fraction (HFNEF), can cause confusion in interpreting results. We investigated the characteristics of cases of acute HFNEF with only modestly elevated BNP.Methods
One hundred forty-two patients with acute or acute exacerbation of chronic HFNEF were divided into two groups by BNP level: BNP < 100 pg/ml (NB group, n = 45) and BNP ≥ 100 pg/ml (B group, n = 97). We compared clinical findings, echocardiography results, and neurohormonal factors between these two groups.Results
In the NB group, a history of open-heart surgery (OHS) was more frequent (71% vs. 22%, p < 0.0001) and hypertension was less frequent (p = 0.0005). Left atrial diameter (LAd) was higher (p = 0.0026), while interventricular septal thickness, posterior wall thickness, relative wall thickness, left ventricular mass index were lower (p = 0.0005, p = 0.0225, p = 0.0114, p = 0.0051, respectively) in the NB group. In patients with HFNEF, a history of OHS remained an independent predictor of BNP level (< 100 pg/ml) after adjustment for hypertension, age, LAd, and interventricular septal thickness (odds ratio 3.6, p = 0.0252).Conclusion
We found associations between acute HFNEF with less elevated BNP and a history of OHS. In a patient suspected of HFNEF, a history of OHS is considered diagnostic evidence of presence of diastolic heart failure when plasma levels of BNP are less elevated. 相似文献12.
D. S. Bogolyubov A. M. Kiselyov S. V. Shabelnikov V. N. Parfenov 《Cell and Tissue Biology》2012,6(5-6):412-422
The nucleus of vitellogenic oocytes of the yellow mealworm Tenebrio molitor contains a karyosphere that consists of condensed chromatin embedded in an extrachromosomal fibrogranular material. Numerous nuclear bodies located freely in the nucleoplasm are also observed. Amongst these bodies, counterparts of nuclear speckles (= interchromatin granule clusters (IGCs)) can be identified by the presence of the marker protein SC35. Microinjections of fluorescently tagged 2??-O-Me(U)22 methyl oligoribonucleotide probes, complementary to poly(A) tails of RNAs, revealed poly(A)+ RNA in the vast majority of IGCs. We found that all T. molitor oocyte IGCs contain heterogeneous ribonucleoprotein (hnRNP) core protein A1 localized to IGCs in an RNA-dependent manner. The extrachromosomal material of the karyosphere and some nucleoplasmic IGCs also contain the adapter protein Aly known to provide a link between pre-mRNA splicing and mRNA export. The essential mRNA export factor/receptor NXF1 was colocalized with Aly. In nucleoplasmic IGCs, NXF1 was found to localize in an RNA-dependent manner, whereas it was RNA-independently located in the extrachromosomal material of the karyosphere. We believe our data provide evidence for the implication of nucleoplasmic IGCs in mRNA biogenesis and retention on the path to nuclear export. 相似文献
13.
M. G. Martynova O. A. Petukhova N. S. Sharlaimova S. V. Shabelnikov O. A. Bystrova 《Cell and Tissue Biology》2018,12(4):342-349
The vertebrate CRF signaling system consists of corticotropin-releasing factor (CRF), two types of receptors to CRF (CRF-R1 and CRF-R2), and CRF-binding protein (CRF-BP). The aim of this study was to investigate the presence and localization of CRF, CRF-R2, and CRF-BP in the snail atrial neuroendocrine complexes, which include granular cells (GCs) and tightly connected nerve fibers and gliointerstitial cells. Immunofluorescence assay and immunogold electron microscopy using polyclonal antibodies against these proteins revealed immunoreactivity in the granules of all these cells. Western-blot analysis of the snailatria lysate using rabbit anti-CRF-R2 polyclonal antibodies revealed a specific band with a weight of 56 kids. These are the first data on the molecular weight of this receptor in mollusks. Furthermore, to clarify the possible functions of CRF in the neuroendocrine complexes, the hormone was added to GCs isolated from the snail atrium. The proportion of degranulated GCs after CRF addition almost doubled (45.5 vs. 24.5% in control, p < 0.05). The results indicate the presence of all three components of the CRF signaling system in the neuroendocrine complexes of snail atrium. In addition, their presence in both secretory and nervous components of the complexes suggests that the CRF signaling system participates in the nervous regulation of secretory activity of GCs and transfer of information from GCs to the CNS. 相似文献
14.
Abstract A new species of nematode, Heth baudini sp. n. from a diplopod (Spirostreptida: Iulomorphidae Verhoeff, 1924) collected in Queensland, Australia, is described and illustrated. The cephalic and cervical cuticular ornamentation of females of H. baudini sp. n. is similar to those of South-East Asian and Australasian Heth species. Heth baudini sp. n. females are particularly close to Heth taynguyeni from Vietnam but can be distinguished by the shape of the lateral lappets, which in H. taynguyeni limit the trapezium-shaped region of smooth cuticle unlike the elliptical region in H. baudini sp. n., and by the presence of lateral spines only half the size. The cuticle of the H. baudini sp. n. is finely annulated along the entire body, whereas H. taynguyeni has broader rings behind the first pair of lateral spines, each consisting of five or six narrower rings separated from each other by deeper furrows. Males of H. baudini sp. n. are characterised by the presence of a bursa-like fold on the tail and can be distinguished from other species of the genus by the presence of somatic papillae embedded into the bursal fold. 相似文献
15.
Kshitiz?GuptaEmail author Dina?Thomas SV?Vidya KV?VenkateshEmail author S?Ramakumar 《BMC bioinformatics》2005,6(1):105
Background
The chemical property and biological function of a protein is a direct consequence of its primary structure. Several algorithms have been developed which determine alignment and similarity of primary protein sequences. However, character based similarity cannot provide insight into the structural aspects of a protein. We present a method based on spectral similarity to compare subsequences of amino acids that behave similarly but are not aligned well by considering amino acids as mere characters. This approach finds a similarity score between sequences based on any given attribute, like hydrophobicity of amino acids, on the basis of spectral information after partial conversion to the frequency domain. 相似文献16.
Estimating synonymous and nonsynonymous substitution rates 总被引:8,自引:4,他引:4
Partitioning the total substitution rate into synnonymous and nonsynonymous
components is a key aspect of many analyses in molecular evolution.
Numerous methods exist for estimating these rates. However, until recently
none of the estimation procedures were based on a sound statistical
footing. In this paper, the evolutionary model of Muse and Gaut (1994) is
used as the basis for two sets of parameters quantifying silent and
replacement substitution rates. The parameters are shown to be equal when
the four nucleotides are equally frequent and unequal otherwise.
Maximum-likelihood estimation of these parameters is described, and the
performance of these estimates is compared to that of existing estimation
procedures. It is shown that the estimates of Nei and Gojobori (1986) are
not unbiased for either set of parameters, although they provide very good
estimates for one set as long as sequence divergence is not too high.
However, some disturbing properties are found for the Nei and Gojobori
estimates. In particular, it is shown that the expected value of the Nei
and Gojobori estimate of silent substitution rate is a function of both the
silent and replacement substitution rates. The maximum-likelihood estimates
have no such problems.
相似文献
17.
A nearly universal feature of intron sequences is that even closely related
species exhibit a large number of insertion/deletion differences. The goal
of the analysis described here is to test whether the observed pattern of
insertion/deletion events in the genealogy of the myosin alkali light chain
(Mlc1) gene is consistent with neutrality, and if not, to determine the
underlying forces of evolutionary change. Mlc1 pre-mRNA is alternatively
spliced, and one constraint is that signals necessary for
tissue-specificity of directed splicing must be conserved. If the total
length of an intron is functionally constrained, then the distribution of
indels on branches of the gene genealogy should reflect a departure from
randomness. Here we perform a phylogenetic analysis, inferring ancestral
states wherever possible on a phylogeny of 29 alleles of Mlc1 from six
species of Drosophila. Observed patterns of indels on the genealogy were
compared to those from simulated data, with the result that we cannot
reject the null hypothesis of neutrality. A clear departure from a neutral
prediction was seen in the excess folding free energy predicted for the
introns flanking the alternatively spliced exon. Relative rate tests also
suggest a retardation in the rate of Mlc1 sequence evolution in the
simulans clade.
相似文献
18.
Alexey G. Mittenberg Valeria O. Kuzyk Sergey V. Shabelnikov Daria P. Gorbach Alla N. Shatrova Olga A. Fedorova 《Cell cycle (Georgetown, Tex.)》2018,17(14):1745-1756
The proteasome is the key player in targeted degradation of cellular proteins and serves as a therapeutic target for treating several blood malignancies. Although in general, degradation of proteins via the proteasome requires their ubiquitination, a subset of proteins can be degraded independently of their ubiquitination by direct interaction with subunits of the 20S proteasome core. Thus, investigation of the proteasome-associated proteins may help identify novel targets of proteasome degradation and provide important insights into the mechanisms of malignant cell proteostasis. Here, using biochemical purification of proteasomes from multiple myeloma (MM) cells followed by mass-spectrometry we have uncovered 77 proteins in total that specifically interacted with the 20S proteasome via its PSMA3 subunit. Our GST pull-down assays followed by western blots validated the interactions identified by mass-spectrometry. Eleven proteins were confirmed to bind PSMA3 only upon apoptotic conditions induced by a combined treatment with the proteasome inhibitor, bortezomib, and genotoxic drug, doxorubicin. Nine of these eleven proteins contained bioinformatically predicted intrinsically disordered regions thus making them susceptible to ubiquitin-independent degradation. Importantly, among those proteins five interacted with the ubiquitin binding affinity matrix suggesting that these proteins may also be ubiquitinylated and hence degraded via the ubiquitin-dependent pathway. Collectively, these PSMA3-interacting proteins represent novel potential substrates for 20S proteasomes upon apoptosis. Furthermore, these data may shed light on the molecular mechanisms of cellular response to chemotherapy.
Abbreviations: BD: bortezomib/doxorubicin treatment; CDK: cyclin-dependent kinases; CHCA: α-cyanohydroxycinnamic acid; IDP: intrinsically disordered proteins; IDR: intrinsically disordered regions; IPG: immobilized pI gradient; MALDI TOF/TOF: matrix-assisted laser desorption/ionization time-of-flight tandem mass-spectrometry; MM: multiple myeloma; ODC: ornithine decarboxylase; PI: proteasomal inhibitors; PSMA: alpha-type 20S proteasome subunits; PTMs: post-translational modifications; SDS-PAGE: sodium dodecylsulphate polyacrylamide gel electrophoresis; UIP: ubiquitin-independent proteasomal proteolysis. 相似文献
19.
Despite extensive studies of cardiac bioactive peptides and their functions in molluscs, soluble proteins expressed in the heart and secreted into the circulation have not yet been reported. In this study, we describe an 18.1-kDa, cysteine-rich atrial secretory protein (CRASP) isolated from the terrestrial snail Achatina achatina that has no detectable sequence similarity to any known protein or nucleotide sequence. CRASP is an acidic, 158-residue, N-glycosylated protein composed of eight alpha-helical segments stabilized with five disulphide bonds. A combination of fold recognition algorithms and ab initio folding predicted that CRASP adopts an all-alpha, right-handed superhelical fold. CRASP is most strongly expressed in the atrium in secretory atrial granular cells, and substantial amounts of CRASP are released from the heart upon nerve stimulation. CRASP is detected in the haemolymph of intact animals at nanomolar concentrations. CRASP is the first secretory protein expressed in molluscan atrium to be reported. We propose that CRASP is an example of a taxonomically restricted gene that might be responsible for adaptations specific for terrestrial pulmonates. 相似文献
20.
A likelihood approach for comparing synonymous and nonsynonymous nucleotide substitution rates, with application to the chloroplast genome 总被引:29,自引:24,他引:5
A model of DNA sequence evolution applicable to coding regions is
presented. This represents the first evolutionary model that accounts for
dependencies among nucleotides within a codon. The model uses the codon, as
opposed to the nucleotide, as the unit of evolution, and is parameterized
in terms of synonymous and nonsynonymous nucleotide substitution rates. One
of the model's advantages over those used in methods for estimating
synonymous and nonsynonymous substitution rates is that it completely
corrects for multiple hits at a codon, rather than taking a parsimony
approach and considering only pathways of minimum change between homologous
codons. Likelihood-ratio versions of the relative-rate test are constructed
and applied to data from the complete chloroplast DNA sequences of Oryza
sativa, Nicotiana tabacum, and Marchantia polymorpha. Results of these
tests confirm previous findings that substitution rates in the chloroplast
genome are subject to both lineage-specific and locus-specific effects.
Additionally, the new tests suggest tha the rate heterogeneity is due
primarily to differences in nonsynonymous substitution rates. Simulations
help confirm previous suggestions that silent sites are saturated, leaving
no evidence of heterogeneity in synonymous substitution rates.
相似文献