Search results for "Complementary"
showing 10 items of 1156 documents
Drimane-type Sesquiterpene Coumarins from Ferula gummosa Fruits Enhance Doxorubicin Uptake in Doxorubicin-resistant Human Breast Cancer Cell Line
2014
ABSTRACT Multidrug resistance (MDR) is the main cause of failure in the chemotherapy of cancer patients. The present study aimed to evaluate the effects of sesquiterpene coumarins of Ferula gummosa fruits on P-glycoprotein (P-gp)–mediated MDR. Drimane-type sesquiterpene coumarins from the fruits of F. gummosa were extracted with dichloromethane and subjected to column chromatography. The effects of the isolated compounds on P-gp–mediated MDR were evaluated in the breast cancer cell line MCF-7 which shows high resistance to doxoribicin (MCF-7/Dox). Phytochemical investigation of dichloromethane extract of F. gummosa fruits resulted in three sesquiterpene coumarins including conferone (1), mo…
The eighth component of human complement: molecular basis of C8A (C81) polymorphism.
1995
Using an exon-specific polymerase chain reaction (PCR) followed by direct DNA sequence analysis we have analyzed the polymorphism of the alpha-chain of the eighth component of human complement (C8) at the DNA level. We found that two common alleles, C8A*A and C8A*B, are characterized by the substitution of a single amino acid (Gln to Lys), which is caused by a point mutation of a single nucleotide (C to A) in exon 3 at position 187 of the mature C8 alpha cDNA sequence. Based on this mutation, an allele-specific PCR was designed detecting the two alleles of C8A. We applied this method to type the C8A polymorphism using DNA samples from a Chinese Han population. The comparison with the data o…
cis-Regulatory sequences driving the expression of the Hbox12 homeobox-containing gene in the presumptive aboral ectoderm territory of the Paracentro…
2008
AbstractEmbryonic development is coordinated by networks of evolutionary conserved regulatory genes encoding transcription factors and components of cell signalling pathways. In the sea urchin embryo, a number of genes encoding transcription factors display territorial restricted expression. Among these, the zygotic Hbox12 homeobox gene is transiently transcribed in a limited number of cells of the animal-lateral half of the early Paracentrotus lividus embryo, whose descendants will constitute part of the ectoderm territory. To obtain insights on the regulation of Hbox12 expression, we have explored the cis-regulatory apparatus of the gene. In this paper, we show that the intergenic region …
TFIIH Operates through an Expanded Proximal Promoter To Fine-Tune c-myc Expression
2004
A continuous stream of activating and repressing signals is processed by the transcription complex paused at the promoter of the c-myc proto-oncogene. The general transcription factor IIH (TFIIH) is held at promoters prior to promoter escape and so is well situated to channel the input of activators and repressors to modulate c-myc expression. We have compared cells expressing only a mutated p89 (xeroderma pigmentosum complementation group B [XPB]), the largest TFIIH subunit, with the same cells functionally complemented with the wild-type protein (XPB/wt-p89). Here, we show structural, compositional, and functional differences in transcription complexes between XPB and XPB/wt-89 cells at t…
Labdane Diterpenes from Stachys plumosa
2000
Three new labdane diterpenoids were isolated from the aerial parts of Stachys plumosa. The first two (1, 2) were the dextrorotatory enantiomers of the known 6-deoxyandalusol and 13-epijabugodiol. Structures were determined using NMR and MS techniques. The absolute stereochemistry of the third compound (3) was not experimentally proved.
Biologically Active Triterpene Saponins from Callus Tissue of Polygala amarella
1999
A new bioactive saponin (1), together with a known saponin (polygalasaponin XXVIII) has been isolated from the callus tissue culture of Polygala amarella. Based on spectroscopic data, especially direct and long-range heteronuclear 2D NMR analysis and on chemical transformations, the structure of 1 was elucidated as 3-O-beta-D-glucopyranosyl presenegenin-28-O-beta-D-galactopyranosyl-(1 --> 3)-beta-D-xylopyranosyl-(1 --> 4)-alpha-L-rhamnopyranosyl-(1 --> 2)-[beta-D-glucopyranosyl-(1 --> 3)]-beta-D-fucopyranoside. Both saponins showed significant immunological properties based on the enhancement of granulocyte phagocytosis in vitro.
An electrospray ionization mass spectrometric study of the extracellular hemoglobins from Chironomus thummi thummi.
1998
The aquatic larvae of the dipteran, Chironomus thummi thummi contain extracellular hemoglobins which exhibit stage-specific expression. We have used maximum entropy-based deconvolution of the complex, multiply charged electrospray ionization mass spectra, to demonstrate the presence of more than 20 components, ranging in mass from 14,417.3 Da to 17,356.5 Da in the 4th instar larvae. Of the 15 major peaks with intensities > 10 relative to 100 for the 14,417.3 Da-component (CTT-IV), only the 15,528.2-Da peak does not correspond to a known amino acid sequence. Since the number of C. thummi thummi globin genes now stands at 27, including one cDNA and not counting three that must encode known gl…
Taxane analysis by high performance liquid chromatography-Nuclear magnetic resonance spectroscopy ofTaxus species
1998
High performance liquid chromatography–nuclear magnetic resonance spectroscopic analyses of taxane diterpenoids from three Taxus species were carried out employing a stopped-flow technique. Several taxanes have been identified from 500 mg leaf samples without prior isolation. © 1998 John Wiley & Sons, Ltd.
Induction of Secondary Metabolites from the Marine-Derived Fungus Aspergillus versicolor through Co-cultivation with Bacillus subtilis
2019
AbstractA new cyclic pentapeptide, cotteslosin C (1), a new aflaquinolone, 22-epi-aflaquinolone B (3), and two new anthraquinones (9 and 10), along with thirty known compounds (2, 4 – 8, 11 – 34) were isolated from a co-culture of the sponge-associated fungus Aspergillus versicolor with Bacillus subtilis. The new metabolites were only detected in the co-culture extract, but not when the fungus was grown under axenic conditions. Furthermore, the co-culture extract exhibited an enhanced accumulation of the known constituents versicolorin B (14), averufin (16), and sterigmatocyctin (19) by factors of 1.5, 2.0, and 4.7, respectively, compared to the axenic fungal culture. The structures of the …
Cloning and sequencing of the chicken egg-white avidin-encoding gene and its relationship with the avidin-related genes Avrl-Avr5
1995
Abstract The gene encoding chicken egg-white avidin (Avd) was amplified from chromosomal DNA, cloned and sequenced. The entire coding region of preavidin (pre-Avd) containing four exons was identified by comparing the Avd gene (1119 bp) with the cDNA. It had a high identity percentage (91–95%) with the previously isolated Avd-related genes 1–5 (Avrl–Avr5) . Interestingly, comparison of Avd with the Avr genes showed that the introns were better conserved (on average 97%) than the exons (90%). The Avd gene, as well as the cDNA, encodes a Gln residue at position 53 of the mature protein, which is in contrast to the previously determined amino-acid sequence.