The function of gene sll0033 from Synechocystis 6803 which is homologous to the bacterial crtI-type phytoene desaturase genes was elucidated as a novel carotene isomerase. Escherichia coli transformed with all genes necessary for the formation of zeta-carotene and expressing a zeta-carotene desaturase synthesized the positional isomer prolycopene (7,9,7',9'Z lycopene) which cannot be cyclized i...

Carotenoid concentrations were measured in serum and in both non-cancerous and cancerous gastric mucosal tissues of Korean patients with gastric cancer (n = 18). Carotenoids in serum and gastric tissue were extracted with chloroform/methanol (2:1), and measured using reverse-phase high-performance liquid chromatography with a C30 column. Cryptoxanthin and -carotene were the major carotenoids in...

β-carotene is one of the major carotenoids in the human diet which shows pro-vitamin A activity, and is associated with prevention of cardiovascular diseases, cancer, and immune system enhancer. However, the poor water-solubility, high melting point, and chemical instability of carotenoids is currently a challenge to their application in the food sector. In this research, the characteristics of...

BACKGROUND: Vitamin A which is found in different tissuesand organs plays a particular role in detecting clinical signs invarious deficiency conditions. However, sometimes the marginaldeficiency is present in a way that clinical signs are not visible butperformance defects, such as infertility is seen. OBJECTIVES: Inthis study, the normal baseline levels of vitamin Aand β-carotene inclinically ...

The small intestine is probably the major site for the conversion of p-carotene into retinol ester (vitamin A ester)1 in the mammal (2-5), but other tissues are capable of catalyzing this cleavage reaction, e.g. the conversion takes place in viva after removal of the intestine (6) and of various other organs (6-9). Direct evidence for the participation of other tissues, however, is lacking. Alt...

Neuroblastoma is a solid tumor often diagnosed in childhood. While there have been intense efforts to develop a treatment for neuroblastoma, current therapies remain unsuccessful due to high rate of resistance and metastasis. Most cancers originate from a subset of self-renewing cells, primarily cancer stem cells (CSCs), which establish a tumor through continuous self-renewal and differentiatio...

We present a sensitive tracer method, suitable for in vivo human research, that uses beta-[(14)C]carotene coupled with accelerator mass spectrometry (AMS) detection. Using this approach, the concentration-time course of a physiological (306 microgram 200 nCi) oral dose of beta-[(14)C]carotene was determined for 209 days in plasma. Analytes included beta-[(14)C]carotene, [(14)C]retinyl esters, [...

PURPOSE Vitamin A is essential for vision. The key step in the vitamin A biosynthetic pathway is the oxidative cleavage of beta-carotene into retinal by the enzyme beta,beta-carotene-15,15'-monooxygenase (BCO). The purpose of the study was to investigate beta-carotene metabolism and its effects on BCO expression in the human retinal pigment epithelial (RPE) cell line D407. METHODS BCO mRNA an...

beta-carotene is an antioxidant molecule of commercial value that can be naturally produced by certain microalgae that mostly belong to the genus Dunaliella. So far, nitrogen starvation has been the most efficient condition for enhancing beta-carotene accumulation in Dunaliella. However, while nitrogen starvation promotes beta-carotene accumulation, the cells become non-viable; consequently und...