排序方式: 共有406条查询结果,搜索用时 15 毫秒
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92.
Ruslan Dorfman Weili Li Lei Sun Fan Lin Yongqian Wang Andrew Sandford Peter D. Paré Karen McKay Hana Kayserova Tereza Piskackova Milan Macek Kamila Czerska Dorota Sands Harm Tiddens Sonia Margarit Gabriela Repetto Marci K. Sontag Frank J. Accurso Scott Blackman Garry R. Cutting Lap-Chee Tsui Mary Corey Peter Durie Julian Zielenski Lisa J. Strug 《Human genetics》2009,126(6):763-778
Cystic fibrosis (CF) is a monogenic disease due to mutations in the CFTR gene. Yet, variability in CF disease presentation is presumed to be affected by modifier genes, such as those recently demonstrated for the pulmonary aspect. Here, we conduct a modifier gene study for meconium ileus (MI), an intestinal obstruction that occurs in 16–20% of CF newborns, providing linkage and association results from large family and case–control samples. Linkage analysis of modifier traits is different than linkage analysis of primary traits on which a sample was ascertained. Here, we articulate a source of confounding unique to modifier gene studies and provide an example of how one might overcome the confounding in the context of linkage studies. Our linkage analysis provided evidence of a MI locus on chromosome 12p13.3, which was segregating in up to 80% of MI families with at least one affected offspring (HLOD = 2.9). Fine mapping of the 12p13.3 region in a large case–control sample of pancreatic insufficient Canadian CF patients with and without MI pointed to the involvement of ADIPOR2 in MI (p = 0.002). This marker was substantially out of Hardy–Weinberg equilibrium in the cases only, and provided evidence of a cohort effect. The association with rs9300298 in the ADIPOR2 gene at the 12p13.3 locus was replicated in an independent sample of CF families. A protective locus, using the phenotype of no-MI, mapped to 4q13.3 (HLOD = 3.19), with substantial heterogeneity. A candidate gene in the region, SLC4A4, provided preliminary evidence of association (p = 0.002), warranting further follow-up studies. Our linkage approach was used to direct our fine-mapping studies, which uncovered two potential modifier genes worthy of follow-up. 相似文献
93.
Pseudomonas
aeruginosa synthesizes large quantities of exopolysaccharide (EPS), making it an excellent model organism for the study of EPS-mediated
adhesion. The purpose of this investigation was to evaluate the influence of limited nutrients availability in the culture
medium on the composition of EPS produced by P. aeruginosa. The relationship between the EPS production and the adhesion process of the P. aeruginosa cells to stainless steel surface (type 316 L) under starvation conditions were also examined. In all experimental variants
P. aeruginosa produced more EPS with an increase of incubation period upon starvation conditions. Under limited nutrients condition, glucose
dominated in the EPS materials. After 6 days of the process, only glucosyl units were detected in the extracellular matrix
produced by nutrient-deprived P. aeruginosa cells. These extracellular molecules promoted more advanced stages of P. aeruginosa biofilm formation on the surface of stainless steel. 相似文献
94.
Melanie Ann Sacco Kamila Koropacka Eric Grenier Marianne J. Jaubert Alexandra Blanchard Aska Goverse Geert Smant Peter Moffett 《PLoS pathogens》2009,5(8)
Plant NB-LRR proteins confer robust protection against microbes and metazoan
parasites by recognizing pathogen-derived avirulence (Avr) proteins that are
delivered to the host cytoplasm. Microbial Avr proteins usually function as
virulence factors in compatible interactions; however, little is known about the
types of metazoan proteins recognized by NB-LRR proteins and their relationship
with virulence. In this report, we demonstrate that the secreted protein RBP-1
from the potato cyst nematode Globodera pallida elicits defense
responses, including cell death typical of a hypersensitive response (HR),
through the NB-LRR protein Gpa2. Gp-Rbp-1 variants from
G. pallida populations both virulent and avirulent to
Gpa2 demonstrated a high degree of polymorphism, with
positive selection detected at numerous sites. All Gp-RBP-1
protein variants from an avirulent population were recognized by Gpa2, whereas
virulent populations possessed Gp-RBP-1 protein variants both
recognized and non-recognized by Gpa2. Recognition of Gp-RBP-1
by Gpa2 correlated to a single amino acid polymorphism at position 187 in the
Gp-RBP-1 SPRY domain. Gp-RBP-1 expressed
from Potato virus X elicited Gpa2-mediated defenses that required Ran
GTPase-activating protein 2 (RanGAP2), a protein known to interact with the Gpa2
N terminus. Tethering RanGAP2 and Gp-RBP-1 variants via fusion
proteins resulted in an enhancement of Gpa2-mediated responses. However,
activation of Gpa2 was still dependent on the recognition specificity conferred
by amino acid 187 and the Gpa2 LRR domain. These results suggest a two-tiered
process wherein RanGAP2 mediates an initial interaction with pathogen-delivered
Gp-RBP-1 proteins but where the Gpa2 LRR determines which
of these interactions will be productive. 相似文献
95.
Jaroslava Ovesna Kamila Strymplova Stastna Katerina Vaculova Jarmila Milotova 《Biologia》2010,65(1):75-80
The allelic status at bmy1, which encodes the enzyme β-amylase 1 in the barley grain, has an important influence over a cultivar’s malting quality. Changes in the malting process
have been responsible for the need to improve the thermostability of this enzyme. We have compared a published bmy1 haplotyping assay based on TDI-FRET (template-directed dye-terminator incorporation fluorescence resonance energy transfer)
with a SNaPshot protocol by jointly analysing a set of 21 cultivars of known haplotype. The two methods gave the same result,
but the SNaPshot assay was easier to interpret. The SNaPshot assay was therefore used to haplotype the Czech malting barley
core collection with respect to bmy1. The old Czech cultivar Kasticky was the only entry identified as carrying the high thermostability haplotype, with the remainder
carrying either the intermediate or the low thermostability haplotypes. Older materials were the most variable in terms of
bmy1 haplotype, but the majority carried the intermediate type. Most of the descendants of cv. Diamant carried the low thermostability
haplotype. The most recently released cultivars recommended for the brewing of Czech beer tend to carry the intermediate allele. 相似文献
96.
Kamila Rzeznicka Sebastian Schätzle Dominique Böttcher Joachim Klein Uwe T. Bornscheuer 《Applied microbiology and biotechnology》2010,85(5):1417-1425
The nitrile hydratase (NHase, EC 4.2.1.84) genes (α and β subunit) and the corresponding activator gene from Rhodococcus equi TG328-2 were cloned and sequenced. This Fe-type NHase consists of 209 amino acids (α subunit, Mr 23 kDa) and 218 amino acids (β subunit, Mr 24 kDa) and the NHase activator of 413 amino acids (Mr 46 kDa). Various combinations of promoter, NHase and activator genes were constructed to produce active NHase enzyme recombinantly
in E. coli. The maximum enzyme activity (844 U/mg crude cell extract towards methacrylonitrile) was achieved when the NHase activator
gene was separately co-expressed with the NHase subunit genes in E. coli BL21 (DE3). The overproduced enzyme was purified with 61% yield after French press, His-tag affinity chromatography, ultrafiltration
and lyophilization and showed typical Fe-type NHase characteristics: besides aromatic and heterocyclic nitriles, aliphatic
ones were hydrated preferentially. The purified enzyme had a specific activity of 6,290 U/mg towards methacrylonitrile. Enantioselectivity
was observed for aromatic compounds only with E values ranging 5–17. The enzyme displayed a broad pH optimum from 6 to 8.5, was most active at 30°C and showed the highest
stability at 4°C in thermal inactivation studies between 4°C and 50°C. 相似文献
97.
Sebastian Deeg Mathias Gralle Kamila Sroka Mathias B?hr Fred Silvester Wouters Pawel Kermer 《The Journal of cell biology》2010,188(4):505-513
Mutations in the gene coding for DJ-1 protein lead to early-onset recessive forms of Parkinson’s disease. It is believed that loss of DJ-1 function is causative for disease, although the function of DJ-1 still remains a matter of controversy. We show that DJ-1 is localized in the cytosol and is associated with membranes and organelles in the form of homodimers. The disease-related mutation L166P shifts its subcellular distribution to the nucleus and decreases its ability to dimerize, impairing cell survival. Using an intracellular foldase biosensor, we found that wild-type DJ-1 possesses chaperone activity, which is abolished by the L166P mutation. We observed that this aberrant phenotype can be reversed by the expression of the cochaperone BAG1 (Bcl-2–associated athanogene 1), restoring DJ-1 subcellular distribution, dimer formation, and chaperone activity and ameliorating cell survival. 相似文献
98.
Kamila Bledzka Katarzyna Bialkowska Huiqin Nie Jun Qin Tatiana Byzova Chuanyue Wu Edward F. Plow Yan-Qing Ma 《The Journal of biological chemistry》2010,285(40):30370-30374
Kindlins are essential for integrin activation in cell systems and do so by working in a cooperative fashion with talin via their direct interaction with integrin β cytoplasmic tails (CTs). Kindlins interact with the membrane-distal NxxY motif, which is distinct from the talin-binding site within the membrane-proximal NxxY motif. The Tyr residues in both motifs can be phosphorylated, and it has been suggested that this modification of the membrane-proximal NxxY motif negatively regulates interaction with the talin head domain. However, the influence of Tyr phosphorylation of the membrane-distal NxxY motif on kindlin binding is unknown. Using mutational analyses and phosphorylated peptides, we show that phosphorylation of the membrane-distal NITY759 motif in the β3 CT disrupts kindlin-2 recognition. Phosphorylation of this membrane-distal Tyr also disables the ability of kindlin-2 to coactivate the integrin. In direct binding studies, peptides corresponding to the non-phosphorylated β3 CT interacted well with kindlin-2, whereas the Tyr759-phosphorylated peptide failed to bind kindlin-2 with measurable affinity. These observations indicate that transitions between the phosphorylated and non-phosphorylated states of the integrin β3 CT determine reactivity with kindlin-2 and govern the role of kindlin-2 in regulating integrin activation. 相似文献
99.
More than 700 bacterial species inhabit oral cavity of humans. Various oral diseases are related to changes in the structure of this complex community. Their pathogenesis can, thus, be better understood by study of oral microbial flora. As many bacteria are refractory to cultivation, molecular approaches based on PCR followed by downstream analysis are more suitable for community analysis than culture dependent methods. Effective DNA extraction from the sample matrix is a fundamental part of the pre-analytical phase but it can be influenced by processing of the starting material. The aim of this study was to analyze the effects of saliva processing on DNA extraction using several non-commercial isolation procedures. Bacterial chromosomal DNA was extracted from three different sample matrices: fresh saliva, diluted saliva and pelleted saliva using four different extraction methods: phenol chloroform protocol, benzyl-chloride protocol, extraction with Chelex-100 and extraction with Triton X. Extraction from different saliva samples and the use of different extraction methods significantly affected the effectiveness of DNA extraction. The most suitable material for bacterial DNA extraction for molecular analysis is a fresh saliva sample. The most effective methods for isolating salivary DNA are the benzyl-chloride protocol and Chelex-100 extraction. Our results have implications for studies concentrating on salivary microbiome and its role in the pathogenesis of oral diseases. 相似文献
100.
L Matthew Arthur Renee M Demarest Lise Clark Dmitri Gourevitch Kamila Bedelbaeva Rhonda Anderson Andrew Snyder Anthony J Capobianco Paul Lieberman Lionel Feigenbaum E Heber-Katz 《Cell cycle (Georgetown, Tex.)》2010,9(18):3667-3673
The process of regeneration is most readily studied in species of sponge, hydra, planarian and salamander (i.e., newt and axolotl). The closure of MRL mouse ear pinna through-and-through holes provides a mammalian model of unusual wound healing/regeneration in which a blastema-like structure closes the ear hole and cartilage and hair follicles are replaced. Recent studies, based on a broad level of DNA damage and a cell cycle pattern of G2/M “arrest,” showed that p21Cip1/Waf1 was missing from the MRL mouse ear and that a p21-null mouse could close its ear holes. Given the p53/p21 axis of control of DNA damage, cell cycle arrest, apoptosis and senescence, we tested the role of p53 in the ear hole regenerative response. Using backcross mice, we found that loss of p53 in MRL mice did not show reduced healing. Furthermore, cross sections of MRL. p53−/− mouse ears at 6 weeks post-injury showed an increased level of adipocytes and chondrocytes in the region of healing whereas MRL or p21−/− mice showed chondrogenesis alone in this same region, though at later time points. In addition, we also investigated other cell cyclerelated mutant mice to determine how p21 was being regulated. We demonstrate that p16 and Gadd45 null mice show little healing capacity. Interestingly, a partial healing phenotype in mice with a dual Tgfβ/Rag2 knockout mutation was seen. These data demonstrate an independence of p53 signaling for mouse appendage regeneration and suggest that the role of p21 in this process is possibly through the abrogation of the Tgfβ/Smad pathway.Key words: mouse, regeneration, p53, p21, MRL, ear-hole, Tgfβ 相似文献