Ochratoxin A-13C20 is intended for use as an internal standard for the quantification of ochratoxin A (Item No. 11439) by GC- or LC-MS. Ochratoxin A is a mycotoxin that has been found in Aspergillus and Penicillium.{21687} It increases lipid peroxide levels and the number of apoptotic cells, as well as reduces superoxide dismutase activity in rat kidney when administered at a dose of 120 μg/kg.{57301} Topical application of ochratoxin A (80 μg/mouse) induces DNA damage, cell cycle arrest at the G0/G1 phase, and apoptosis in mouse skin cells.{21687} It also initiates tumor formation in a two-stage mouse skin tumorigenesis model. Ochratoxin A has been found as a contaminant in a variety of foods.{21686}
Available on backorder
An internal standard for the quantification of ochratoxin A by GC- or LC-MS
Formal name: N-[[(3R)-5-chloro-3,4-dihydro-8-hydroxy-3-(methyl-13C)-1-oxo-1H-2-benzopyran-7-yl-1,3,4,4a,5,6,7,8,8a-13C9]carbonyl-13C]-L-phenylalanine-13C9
Synonyms: OTA-13C20
Molecular weight: 423.7
CAS: 911392-42-2
Purity: ≥98%
Formulation: A solution in acetonitrile
The tetracycline repressor (TetR) is a transcriptional regulator which normally binds tightly to its palindromic tetO operator DNA, blocking gene expression.{17508} Tet causes the repressor to dissociate from the DNA, allowing transcription to occur. A novel reverse TetR (revTetR) requires tetracycline as a co-repressor to bind tetO and block transcription.{17509,17510} Anhydrotetracycline (hydrochloride) is a powerful effector in both the tetracycline repressor (TetR) and reverse TetR (revTetR) systems, binding the Tet repressor 35-fold more strongly than Tet.{17508,17511} Moreover, anhydrotetracycline poorly binds the 30S ribosomal subunit, compared to Tet,{17512} so it does not act as a general inhibitor of translation and is a poor antibiotic. Perhaps related to this, the concentration of anhydrotetracycline that inhibits eukaryotic cell growth is more than a 1,000-fold above the dose that alters transcription through TetR.{17508}
Available on backorder
1,2-Dipalmitoyl-sn-glycero-3-PC (DPPC) is a zwitterionic glycerophospholipid commonly used in the formation of lipid monolayers, bilayers, and liposomes for use in a variety of applications.{14480,24261,14478,14479} It has been used in the formation of proteoliposomes for implantation of γ-glutamyl transpeptidase into human erythrocyte membranes.{14478} Incorporation of glycosphingolipid antigens into DPPC-containing liposomes increases the immunogenicity of the antigens in mice.{14479}
Available on backorder
Cyclin-dependent kinases (CDKs) are key regulators of cell cycle progression and are therefore promising targets for cancer therapy. (R)-Roscovitine is a potent inhibitor of Cdk2/cyclin E with an IC50 value of 0.1 µM.{14988} It also inhibits Cdk7/cyclin H, Cdk5/p35, and cell division cycle (cdc)/cyclin B with IC50 values of 0.49, 0.16, and 0.65 µM, respectively.{14987,14988,14991} (R)-Roscovitine inhibits the growth of rapidly proliferating cells with an average IC50 value of 15.2 µM against a panel of 19 human tumor cell lines.{14988} In murine models of polycystic kidney disease, (R)-roscovitine effectively inhibited disease progression at doses of 50-100 mg/kg.{14564}
Available on backorder
The maintenance of embryonic stem cells in culture typically requires feeder cells and various exogenous factors found in serum. Murine embryonic stem (mES) cells can be maintained in the absence of feeder cells and serum but require the leukemia inhibitor factor (LIF) and bone morphogenic protein (BMP) to prevent differentiation and promote self-renewal. SC-1 is a small molecule activator of stem cell renewal that allows the propagation of OG2 mES cells for at least 10 passages in an undifferentiated state.{14533} The activity of SC-1 is mediated by the combined inhibition of RasGAP and ERK1 with Kd values of 98 and 212 nM, respectively.{14533} Inhibition of RasGAP increases Ras signaling via the PI3-kinase pathway which promotes self-renewal, whereas inhibition of ERK blocks differentiation.
Available on backorder