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931.
Cholesterol regulates Hedgehog (Hh) signaling during early vertebrate development. Smith-Lemli-Opitz syndrome (SLOS) is caused by defects in 7-dehydrocholesterol reductase (DHCR7), an enzyme catalyzing the final step of cholesterol biosynthesis. Many developmental malformations attributed to SLOS occur in tissues and organs where Hh signaling is required for development, but the precise role of DHCR7 deficiency in this disease remains murky. We report that DHCR7 and Sonic Hedgehog (Shh) are co-expressed during midline development in Xenopus embryos. DHCR7 has previously been implicated to function as a positive regulator of Hh signaling that acts to regulate the cholesterol adduction of Hh ligand or to affect Hh signaling in the responding cell. We present gain- and loss-of-function analyses suggesting that DHCR7 functions as a negative regulator of Hh signaling at the level or downstream of Smoothened (Smo) and affects intracellular Hh signaling. Our analysis also raises the possibility that the human condition SLOS is caused not only by disruption of the enzymatic role of DHCR7 as a reductase in cholesterol biosynthesis, but may also involve defects in DHCR7 resulting in derepression of Shh signaling. 相似文献
932.
A ParaHox gene cluster is composed of three genes (Gsx, Xlox, and Cdx). It has been proposed that all three ParaHox genes were present in the last common ancestor to the lophotrochozoan protostomes and the deuterostomes and that gene loss event has occurred in the ecdysozoan lineage. In this paper, we report the existence of all three ParaHox genes in Perionyx excavatus, a clitellate annelid. Although orthologs of each of the three ParaHox genes were previously discovered from other lopotrochozoan taxa, this study constitutes the first reported isolation of all three ParaHox genes in the same clitellate species.Bum Joon Park and Sung-Jin Cho contributed equally to this work. 相似文献
933.
Kim DW Kim SY An JJ Lee SH Jang SH Won MH Kang TC Chung KH Jung HH Cho SW Choi JH Park J Eum WS Choi SY 《Journal of biochemistry and molecular biology》2006,39(5):642-647
Botulinum neurotoxin A (BoNT/A) has been used therapeutically to treat muscular hypercontractions and sudomotor hyperactivity and it has been reported that BoNT/A might have analgesic properties in headache. PEP-1 peptide is a known carrier peptide that delivers full-length native proteins in vitro and in vivo. In this study, a BoNT/A gene were fused with PEP-1 peptide in a bacterial expression vector to produce a genetic in-frame PEP-1-BoNT/A fusion protein. The expressed and purified PEP-1-BoNT/A fusion proteins were efficiently transduced into cells in a time- and dose-dependent manner when added exogenously in a culture medium. In addition, immunohistochemical analysis revealed that PEP-1-BoNT/A fusion protein efficiently penetrated into the epidermis as well as the dermis of the subcutaneous layer, when sprayed on mice skin. These results suggest that PEP-1-BoNT/A fusion protein provide an efficient strategy for therapeutic delivery in various human diseases related to this protein. 相似文献
934.
Y. J. Cho S. Y. Kim J. Kim E. K. Choe S. I. Kim H. J. Shin 《Biotechnology and Bioprocess Engineering》2006,11(3):230-234
In this study, we describe a one-step chemoenzymatic reaction for the production of natural blue pigments, in which the geniposide
from Gardenia extracts is transformed by glycosidases to genipin. Genipin is then allowed to react with amino acids, thereby
generating a natural blue pigment. The β-glycosidases, most notably isolase (a variant of β-glucanase), recombinant β-glucosidase,
Cellulase T, and amylases, were shown to hydrolyze geniposide to produce the desired pigments, whereas the α-glycosidases
did not. Among the 20 tested amino acids, glycine and tyrosine were associated with the highest dye production yields. The
optimal molar ratio of geniposide to glycine, two reactants relevant to pigment production, was unity. The natural blue pigments
produced in this study were used to dye cotton, silk, and wool. The color yields of the pigments were determined to be significantly
higher than those of other natural dyes. Furthermore, the color fastness properties of these dyes were fairly good, even in
the absence of mordant. 相似文献
935.
Lee K Ryu EK Choi KS Cho MC Jeong JJ Choi EN Lee SO Yoon DY Hwang I Kim CK 《Journal of microbiology (Seoul, Korea)》2006,44(2):192-199
Pseudomonas putida KL47 is a natural isolate that assimilates benzene, 1-alkylbenzene (C(1)-C(4)), biphenyl, p-cumate, and p-cymene. The genetic background of strain KL47 underlying the broad range of growth substrates was examined. It was found that the cym and cmt operons are constitutively expressed due to a lack of the cymR gene, and the tod operon is still inducible by toluene and biphenyl. The entire array of gene clusters responsible for the catabolism of toluene and p-cymene/p-cumate has been cloned in a cosmid vector, pLAFR3, and were named pEK6 and pEK27, respectively. The two inserts overlap one another and the nucleotide sequence (42,505 bp) comprising the cym, cmt, and tod operons and its flanking genes in KL47 are almost identical (>99%) to those of P. putida F1. In the cloned DNA fragment, two genes with unknown functions, labeled cymZ and cmtR, were newly identified and show high sequence homology to dienelactone hydrolase and CymR proteins, respectively. The cmtR gene was identified in the place of the cmtI gene of previous annotation. Western blot analysis showed that, in strains F1 and KL47, the todT gene is not expressed during growth on Luria Bertani medium. In minimal basal salt medium, expression of the todT gene is inducible by toluene, but not by biphenyl in strain F1; however, it is constantly expressed in strain KL47, indicating that high levels of expression of the todST genes with one amino acid substitution in TodS might provide strain KL47 with a means of adaptation of the tod catabolic operon to various aromatic hydrocarbons. 相似文献
936.
SUMMARY: WebCell is a web-based environment for managing quantitative and qualitative information on cellular networks and for interactively exploring their steady-state and dynamic behaviors in response to systemic perturbations. It is designed as a user-friendly web interface, allowing users to efficiently construct, visualize, analyze and store reaction network models, thereby facilitating kinetic modeling and in silico simulation of biological systems of interest. A collected model library is also available to provide comprehensive implications for cellular dynamics of the published models. 相似文献
937.
938.
Cho EK Tchinda J Freeman JL Chung YJ Cai WW Lee C 《Cytogenetic and genome research》2006,115(3-4):262-272
Array-based comparative genomic hybridization (aCGH) is a molecular cytogenetic technique used in detecting and mapping DNA copy number alterations. aCGH is able to interrogate the entire genome at a previously unattainable, high resolution and has directly led to the recent appreciation of a novel class of genomic variation: copy number variation (CNV) in mammalian genomes. All forms of DNA variation/polymorphism are important for studying the basis of phenotypic diversity among individuals. CNV research is still at its infancy, requiring careful collation and annotation of accumulating CNV data that will undoubtedly be useful for accurate interpretation of genomic imbalances identified during cancer research. 相似文献
939.
Recently, heterotrophic nanoflagellates (HNF) have been reported to actively ingest prokaryotes in high salinity waters. We report the isolation and culture of an HNF from a Korean saltern pond of 300‰ salinity. The organism is biflagellated with an acronematic anterior flagellum and never glides on surfaces. The mitochondria have tubular cristae. Neither transitional helix nor spiral fiber were observed in the transition zones of the flagella. The cell has a cytostome supported by an arc of eight microtubules, suggesting that our isolate is a bicosoecid. Our isolate had neither mastigonemes, lorica, body scales, nor cytopharynx and thus could not be placed in any of the presently described bicosoecid genera. Phylogenetic analysis of 18S rRNA gene sequences from stramenopiles confirmed the bicosoecid affinities of our isolate, but did not place it within any established genus or family. Its closest relatives include Caecitellus and Cafeteria. The optimal range of growth temperature was 30–35°C. The isolated HNF grew optimally at 150‰ salinity and tolerated up to 363‰ salinity, but it failed to grow below 75‰ salinity, indicating that it could be a borderline extreme halophile. On the basis of its morphological features and position in 18S rRNA trees we propose a novel genus for our isolate; Halocafeteria, n. gen. The species name Halocafeteria seosinensis sp. nov. is proposed. 相似文献
940.
Rice Chlorina-1 and Chlorina-9 encode ChlD and ChlI subunits of Mg-chelatase, a key enzyme for chlorophyll synthesis and chloroplast development 总被引:9,自引:0,他引:9
Photosynthetic organisms exhibit a green color due to the accumulation of chlorophyll pigments in chloroplasts. Mg-protoporphyrin IX chelatase (Mg-chelatase) comprises three subunits (ChlH, ChlD and ChlI) and catalyzes the insertion of Mg2+ into protoporphyrin IX, the last common intermediate precursor in both chlorophyll and heme biosyntheses, to produce Mg-protoporphyrin IX (MgProto). Chlorophyll deficiency in higher plants results in chlorina (yellowish-green) phenotype. To date, 10 chlorina (chl) mutants have been isolated in rice, but the corresponding genes have not yet been identified. Rice Chl1 and Chl9 genes were mapped to chromosome 3 and isolated by map-based cloning. A missense mutation occurred in a highly conserved amino acid of ChlD in the chl1 mutant and ChlI in the chl9 mutant. Ultrastructural analyses have revealed that the grana are poorly stacked, resulting in the underdevelopment of chloroplasts. In the seedlings fed with aminolevulinate-dipyridyl in darkness, MgProto levels in the chl1 and chl9 mutants decreased up to 25% and 31% of that in wild-type, respectively, indicating that the Mg-chelatase activity is significantly reduced, causing the eventual decrease in chlorophyll synthesis. Furthermore, Northern blot analysis indicated that the nuclear genes encoding the three subunits of Mg-chelatase and LhcpII in chl1 mutant are expressed about 2-fold higher than those in WT, but are not altered in the chl9 mutant. This result indicates that the ChlD subunit participates in negative feedback regulation of plastid-to-nucleus in the expression of nuclear genes encoding chloroplast proteins, but not the ChlI subunit.Haitao Zhang and Jinjie Li contributed equally to this work 相似文献