Mechanisms for the uptake and transport of carotenoids, essential nutrients for humans, are not well understood in any animal system. The Y (Yellow blood) gene, a critical cocoon color determinant in the silkworm Bombyx mori, controls the uptake of carotenoids into the intestinal mucosa and the silk gland. Here we provide evidence that the Y gene corresponds to the intracellular carotenoid-binding protein (CBP) gene. In the Y recessive strain, the absence of an exon, likely due to an incorrect mRNA splicing caused by a transposon-associated genomic deletion, generates a nonfunctional CBP mRNA, resulting in colorless hemolymph and white cocoons. Enhancement of carotenoid uptake and coloration of the white cocoon was achieved by germ-line transformation with the CBP gene. This study demonstrates the existence of a genetically facilitated intracellular process beyond passive diffusion for carotenoid uptake in the animal phyla, and paves the way for modulating silk color and lipid content through genetic engineering.carotenoid transport ͉ cocoon color ͉ transgenic silkworm
According to the traditional usage of the plant for antiinflammation and analgesia, Leucas aspera was tested for its prostaglandin (PG) inhibitory and antioxidant activities. The extract showed both activities, i.e., inhibition at 3 x 10(-4) g/ml against PGE(1)- and PGE(2)-induced contractions in guinea pig ileum and a 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging effect. The separation guided by the activities in these dual assay methods provided eight lignans and four flavonoids, LA-1- -12, among which LA-1- -7 and LA-10- -12 were identified as nectandrin B, meso-dihydroguaiaretic acid, macelignan, acacetin, apigenin 7-O-[6"-O-(p-coumaroyl)-beta-D-glucoside], chrysoeriol, apigenin, erythro-2-(4-allyl-2, 6-dimethoxyphenoxy)-1-(4-hydroxy-3-methoxyphenyl)propan-1-ol, myristargenol B, and machilin C, respectively. LA-8 was determined to be (-)-chicanine, the new antipode of the (+) compound, by spectroscopic methods including CD and ORD. Chiral-HPLC analysis of LA-9 showed that it was a mixture of two enantiomers, (7R, 8R)- and (7S, 8S)-licarin A. All of these components were first isolated from L. aspera. PG inhibition was observed in LA-1, LA-2, and LA-5, and antioxidant activity in LA-1- -3 and LA-8- -12.
In view of their scientific understanding and potential usage, we have continuously investigated traditional medicines to clarify the active components and their pharmacological properties.1-4) Saposhnikovia root (Saposhnikovia divaricata SCHISCHKIN, syn. Ledebouriella seseloides WOLFF; Umbelliferae) is an important Chinese and Japanese traditional medicine, called Fang-feng and Bofu, respectively. 5,6) The herb is listed as a high-grade drug in the old Chinese Materia Medica, Shen Nung Pen Tsao Ching, and is applied for headaches, vertigo, generalized aching and arthralgia due to "wind, cold and dampness" in the traditional medical system.7) It has been used in many prescriptions, including those for the treatment of analgesic symptoms.Pharmacological experiments using the extract reported its suppression of adjuvant arthritis, inhibitory effects on the CNS and peptic ulcers, and fegrifugal analgesic, anti-convulsant and anti-inflammatory activities, etc.8-11) Chemical study on this herb had been done, and many components such as chromones, coumarins and polyacetylenes were isolated. [12][13][14] However, it has not been clearly identified which components contribute to the pharmacological efficacy, such as analgesia, of this traditional medicine. In Japan, Glehnia root, named Hama-Bofu (Glehnia littoralis FR. SCHMIDT ex MIQUEL; Umbelliferae), is used for the same purpose as Bofu (Saposhnikovia root), and in prescriptions the two medicines are often confused. With respect to Glehnia root, we recently identified the active components which are responsible for the analgesia and/or a prolongation effect on pentobarbitalinduced hypnosis caused by the inhibition of liver-metabolizing enzymes.2) Some of the active components in Glehnia root, such as furanocoumarins and polyacetylenes, are the same as the constituents in Bofu. By applying activity-oriented separation to the extract of Saposhnikovia root, the analgesic components of this herbal medicine can be clarified in this paper, and the activity-mechanisms of the components are also discussed. Results and DiscussionThe methanol extract of Saposhnikovia root showed an analgesic effect at a dose of 2 g/kg in mice by the acetic acidinduced writhing method. The extract also caused a prolongation effect on pentobarbital-induced hypnosis in mice at a dose of 3 g/kg. The separation of the extract was mainly carried out by following the writhing inhibition in mice with oral administration of samples as an isolation guide (Chart 1). Partition using ethyl acetate, n-butanol and water concentrated the activity to the ethyl acetate fraction, which was further separated by Sephadex LH-20 chromatography. The obtained analgesic fraction, fr. 1-C, also showed the prolongation effect on pentobarbital-induced sleeping time in mice. The following silica gel chromatography, however, gave two active fractions, fr. 2-A and fr. 2-B. The latter fraction showed only analgesia at a dose of 150 mg/kg and no prolongation effect at a dose of 200 mg/kg, while the former exhibited both effects...
A mixed microbial culture capable of metabolizing deoxynivalenol was obtained from soil samples by an enrichment culture procedure. A bacterium (strain E3-39) isolated from the enrichment culture completely removed exogenously supplied deoxynivalenol from culture medium after incubation for 1 day. On the basis of morphological, physiological, and phylogenetic studies, strain E3-39 was classified as a bacterium belonging to the Agrobacterium-Rhizobium group. Thin-layer chromatographic analysis indicated the presence of one major and two minor metabolites of deoxynivalenol in ethyl acetate extracts of the E3-39 culture filtrates. The main metabolite was identified as 3-keto-4-deoxynivalenol by mass spectroscopy and 1 H and 13 C nuclear magnetic resonance analysis. The immunosuppressive toxicity of 3-keto-4-deoxynivalenol was evaluated by means of a bioassay based on the mitogen-induced and mitogen-free proliferations of mouse spleen lymphocytes. This compound exhibited a remarkably decreased (to less than one tenth) immunosuppressive toxicity relative to deoxynivalenol, indicating that the 3-OH group in deoxynivalenol is likely to be involved in exerting its immunosuppressive toxicity. Strain E3-39 was also capable of transforming 3-acetyldeoxynivalenol but not nivalenol and fusarenon-X.
The transport pathway of specific dietary carotenoids from the midgut lumen to the silk gland in the silkworm, Bombyx mori, is a model system for selective carotenoid transport because several genetic mutants with defects in parts of this pathway have been identified that manifest altered cocoon pigmentation. In the wild-type silkworm, which has both genes, Yellow blood (Y) and Yellow cocoon (C), lutein is transferred selectively from the hemolymph lipoprotein to the silk gland cells where it is accumulated into the cocoon. The Y gene encodes an intracellular carotenoid-binding protein (CBP) containing a lipid-binding domain known as the steroidogenic acute regulatory protein-related lipid transfer domain. Positional cloning and transgenic rescue experiments revealed that the C gene encodes Cameo2, a transmembrane protein gene belonging to the CD36 family genes, some of which, such as the mammalian SR-BI and the fruit fly ninaD, are reported as lipoprotein receptors or implicated in carotenoid transport for visual system. In C mutant larvae, Cameo2 expression was strongly repressed in the silk gland in a specific manner, resulting in colorless silk glands and white cocoons. The developmental profile of Cameo2 expression, CBP expression, and lutein pigmentation in the silk gland of the yellow cocoon strain were correlated. We hypothesize that selective delivery of lutein to specific tissue requires the combination of two components: 1) CBP as a carotenoid transporter in cytosol and 2) Cameo2 as a transmembrane receptor on the surface of the cells.All organisms exposed to light contain carotenoids, which are yellow to red C 40 hydrophobic isoprenoid pigments. Carotenoids play pivotal roles in living organisms as precursors of vitamin A, antioxidants, and colorants (1). Their potential roles in medicine have recently been investigated. For example, macular accumulation of the carotenoids lutein and zeaxanthin is associated with a decreased risk of age-related macular degeneration (2), the leading cause of blindness in the developed world. Although plants, certain fungi, and bacteria synthesize carotenoids, animals appear to be incapable of synthesizing these molecules de novo. Therefore, animals must acquire carotenoids from dietary sources, and subsequently transport them to cells of target tissues.The delivery of lipids, including carotenoids, to cells can be divided into three categories: 1) enzyme-mediated processes, such as the action of lipoprotein lipase on very low density lipoproteins, which converts a lipoprotein-bound lipid, triacylglycerol, into a water-soluble product, fatty acid, which diffuses into cells and leaves behind in the blood a lipoprotein product depleted in triacylglycerol (3); 2) receptor-mediated endocytosis, such as the uptake of low density lipoproteins by low density lipoprotein receptor, in which the entire lipoprotein particle is taken into the cell and metabolized (4); and 3) the delivery of specific lipids to specific tissues devoid of lipoprotein degradation, called selective lip...
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