550 research outputs found
Current situation and prospect of micro injection molding machines
2004-2005 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe
Association of tumor necrosis factor genetic polymorphism with chronic atrophic gastritis and gastric adenocarcinoma in Chinese Han population.
0.05). However, TNF-beta Ncol*1/2 and d2/d6 genotypes did not relate to age, gender, grade of differentiation and clinicopathologic stage in patients with gastric adenocarcinoma. The frequency of TNFa6b5c1 haplotype homozygote was significantly lower in patients with gastric adenocarcinoma than in healthy controls (1.79% vs 15.85%, P=0.006). CONCLUSION: TNFa10 allele may be a risk factor for chronic atrophic gastritis. TNF-beta Ncol*1/2 and d2/d6 genotypes are associated with the susceptibility to gastric adenocarcinoma, whereas TNFa6b5c1 haplotype homozygote may contribute to the resistance against gastric adenocarcinoma
Vomiting and wasting disease associated with hemagglutinating encephalomyelitis viruses infection in piglets in jilin, china
One coronavirus strain was isolated from brain tissues of ten piglets with evident clinical manifestations of vomiting, diarrhea and dyskinesia in Jilin province in China. Antigenic and genomic characterizations of the virus (isolate PHEV-JLsp09) were based on multiplex PCR and negative staining electron microscopy and sequence analysis of the Hemagglutinin-esterase (HE) gene. These piglets were diagnosed with Porcine hemagglutinating encephalomyelitis virus (PHEV)
Why Is the Correlation between Gene Importance and Gene Evolutionary Rate So Weak?
One of the few commonly believed principles of molecular evolution is that functionally more important genes (or DNA sequences) evolve more slowly than less important ones. This principle is widely used by molecular biologists in daily practice. However, recent genomic analysis of a diverse array of organisms found only weak, negative correlations between the evolutionary rate of a gene and its functional importance, typically measured under a single benign lab condition. A frequently suggested cause of the above finding is that gene importance determined in the lab differs from that in an organism's natural environment. Here, we test this hypothesis in yeast using gene importance values experimentally determined in 418 lab conditions or computationally predicted for 10,000 nutritional conditions. In no single condition or combination of conditions did we find a much stronger negative correlation, which is explainable by our subsequent finding that always-essential (enzyme) genes do not evolve significantly more slowly than sometimes-essential or always-nonessential ones. Furthermore, we verified that functional density, approximated by the fraction of amino acid sites within protein domains, is uncorrelated with gene importance. Thus, neither the lab-nature mismatch nor a potentially biased among-gene distribution of functional density explains the observed weakness of the correlation between gene importance and evolutionary rate. We conclude that the weakness is factual, rather than artifactual. In addition to being weakened by population genetic reasons, the correlation is likely to have been further weakened by the presence of multiple nontrivial rate determinants that are independent from gene importance. These findings notwithstanding, we show that the principle of slower evolution of more important genes does have some predictive power when genes with vastly different evolutionary rates are compared, explaining why the principle can be practically useful despite the weakness of the correlation
Somatic ‘Soluble’ Adenylyl Cyclase Isoforms Are Unaffected in Sacytm1Lex/Sacytm1Lex ‘Knockout’ Mice
BACKGROUND: Mammalian Soluble adenylyl cyclase (sAC, Adcy10, or Sacy) represents a source of the second messenger cAMP distinct from the widely studied, G protein-regulated transmembrane adenylyl cyclases. Genetic deletion of the second through fourth coding exons in Sacy(tm1Lex)/Sacy(tm1Lex) knockout mice results in a male sterile phenotype. The absence of any major somatic phenotype is inconsistent with the variety of somatic functions identified for sAC using pharmacological inhibitors and RNA interference. PRINCIPAL FINDINGS: We now use immunological and molecular biological methods to demonstrate that somatic tissues express a previously unknown isoform of sAC, which utilizes a unique start site, and which 'escapes' the design of the Sacy(tm1Lex) knockout allele. CONCLUSIONS/SIGNIFICANCE: These studies reveal increased complexity at the sAC locus, and they suggest that the known isoforms of sAC play a unique function in male germ cells
Observation of a ppb mass threshoud enhancement in \psi^\prime\to\pi^+\pi^-J/\psi(J/\psi\to\gamma p\bar{p}) decay
The decay channel
is studied using a sample of events collected
by the BESIII experiment at BEPCII. A strong enhancement at threshold is
observed in the invariant mass spectrum. The enhancement can be fit
with an -wave Breit-Wigner resonance function with a resulting peak mass of
and a
narrow width that is at the 90% confidence level.
These results are consistent with published BESII results. These mass and width
values do not match with those of any known meson resonance.Comment: 5 pages, 3 figures, submitted to Chinese Physics
Circumstellar discs: What will be next?
This prospective chapter gives our view on the evolution of the study of
circumstellar discs within the next 20 years from both observational and
theoretical sides. We first present the expected improvements in our knowledge
of protoplanetary discs as for their masses, sizes, chemistry, the presence of
planets as well as the evolutionary processes shaping these discs. We then
explore the older debris disc stage and explain what will be learnt concerning
their birth, the intrinsic links between these discs and planets, the hot dust
and the gas detected around main sequence stars as well as discs around white
dwarfs.Comment: invited review; comments welcome (32 pages
Structure-guided selection of specificity determining positions in the human kinome
Background:
The human kinome contains many important drug targets. It is well-known that inhibitors of protein kinases bind with very different selectivity profiles. This is also the case for inhibitors of many other protein families. The increased availability of protein 3D structures has provided much information on the structural variation within a given protein family. However, the relationship between structural variations and binding specificity is complex and incompletely understood. We have developed a structural bioinformatics approach which provides an analysis of key determinants of binding selectivity as a tool to enhance the rational design of drugs with a specific selectivity profile.
Results:
We propose a greedy algorithm that computes a subset of residue positions in a multiple sequence alignment such that structural and chemical variation in those positions helps explain known binding affinities. By providing this information, the main purpose of the algorithm is to provide experimentalists with possible insights into how the selectivity profile of certain inhibitors is achieved, which is useful for lead optimization. In addition, the algorithm can also be used to predict binding affinities for structures whose affinity for a given inhibitor is unknown. The algorithm’s performance is demonstrated using an extensive dataset for the human kinome.
Conclusion:
We show that the binding affinity of 38 different kinase inhibitors can be explained with consistently high precision and accuracy using the variation of at most six residue positions in the kinome binding site. We show for several inhibitors that we are able to identify residues that are known to be functionally important
Oxidized LDL Receptor 1 (OLR1) as a Possible Link between Obesity, Dyslipidemia and Cancer
Recent studies have linked expression of lectin-like ox-LDL receptor 1
(OLR1) to tumorigenesis. We analyzed microarray data from
Olr1 knockout (KO) and wild type (WT) mice for genes
involved in cellular transformation and evaluated effects of
OLR1 over-expression in normal mammary epithelial cells
(MCF10A) and breast cancer cells (HCC1143) in terms of gene expression,
migration, adhesion and transendothelial migration. Twenty-six out of 238 genes
were inhibited in tissues of OLR1 KO mice; the vast majority of OLR1 sensitive
genes contained NF-κB binding sites in their promoters. Further studies
revealed broad inhibition of NF-kB target genes outside of the
transformation-associated gene pool, with enrichment themes of defense response,
immune response, apoptosis, proliferation, and wound healing. Transcriptome of
Olr1 KO mice also revealed inhibition of de
novo lipogenesis, rate-limiting enzymes fatty acid synthase
(Fasn), stearoyl-CoA desaturase (Scd1) and
ELOVL family member 6 (Elovl6), as well as lipolytic
phospholipase A2 group IVB (Pla2g4b). In studies comparing
MCF10A and HCC1143, the latter displayed 60% higher OLR1
expression. Forced over-expression of OLR1 resulted in
upregulation of NF-κB (p65) and its target pro-oncogenes involved in
inhibition of apoptosis (BCL2, BCL2A1,
TNFAIP3) and regulation of cell cycle
(CCND2) in both cell lines. Basal expression of
FASN, SCD1 and PLA2G4B,
as well as lipogenesis transcription factors PPARA,
SREBF2 and CREM, was higher in HCC1143
cells. Over-expression of OLR1 in HCC1143 cells also enhanced
cell migration, without affecting their adherence to TNFα-activated
endothelium or transendothelial migration. On the other hand,
OLR1 neutralizing antibody inhibited both adhesion and
transmigration of untreated HCC1143 cells. We conclude that
OLR1 may act as an oncogene by activation of NF-kB target
genes responsible for proliferation, migration and inhibition of apoptosis and
de novo lipogenesis genes
VASP: A Volumetric Analysis of Surface Properties Yields Insights into Protein-Ligand Binding Specificity
Many algorithms that compare protein structures can reveal similarities that suggest related biological functions, even at great evolutionary distances. Proteins with related function often exhibit differences in binding specificity, but few algorithms identify structural variations that effect specificity. To address this problem, we describe the Volumetric Analysis of Surface Properties (VASP), a novel volumetric analysis tool for the comparison of binding sites in aligned protein structures. VASP uses solid volumes to represent protein shape and the shape of surface cavities, clefts and tunnels that are defined with other methods. Our approach, inspired by techniques from constructive solid geometry, enables the isolation of volumetrically conserved and variable regions within three dimensionally superposed volumes. We applied VASP to compute a comparative volumetric analysis of the ligand binding sites formed by members of the steroidogenic acute regulatory protein (StAR)-related lipid transfer (START) domains and the serine proteases. Within both families, VASP isolated individual amino acids that create structural differences between ligand binding cavities that are known to influence differences in binding specificity. Also, VASP isolated cavity subregions that differ between ligand binding cavities which are essential for differences in binding specificity. As such, VASP should prove a valuable tool in the study of protein-ligand binding specificity
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