Absorption and tissue distribution of cholesterol in <i>Manduca sexta</i>

Jouni, Zeina E.; Zamora, Jorge; Wells, Michael A.

doi:10.1002/arch.10017

Cited by 43 publications

(31 citation statements)

References 27 publications

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“…Great advances have been made in understanding vascular lipoprotein cholesterol transport, and only a few proteins are known to be involved in cholesterol transport and metablism, such as the haemolymph lipophorin (Soulages and Brenner 1991;Jouni et al 2002) and lipoprotein (Bianchi and Capurro 1991). However, intracellular cholesterol trafficking is only beginning to be resolved.…”

Section: Discussionmentioning

confidence: 99%

Molecular cloning and characterization ofBombyx moristerol carrier protein x/sterol carrier protein 2 (SCPx/SCP2) gene

et al. 2006

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Cholesterol transport is a very important process in insect. We have isolated the Bombyx mori sterol carrier protein x (BmSCPx) cDNA and sterol carrier protein 2 (BmSCP2) cDNA: a 1.7 kb clone encoding SCPx, a 3-ketoacyl CoA thiolase, and 0.6 kb clone presumably encoding SCP2, which is thought to be an intracellular lipid transfer protein. Interestingly, the identical gene SCPx/SCP2 encodes the two types of transcripts by alternative splicing mechanism in Bombyx mori. The SCPx mRNA spans two exons in genome, and conceptual translation of the SCPx cDNA encodes a protein of 536 amino acids, which contains a thiolase domain and a SCP2 domain. Whereas the SCP2 mRNA partly lakes the first exon, and the SCP2 is a 146 amino acids containing a SCP2 domain only. Both BmSCPx and BmSCP2 have a putative peroxisomal targeting signal in the C-terminal region. BmSCPx shares 94 and 72% similarity to Spodoptera littoralis SCPx and human SCPx, respectively. RT-PCR analysis reveals that transcripts of BmSCP2 were detected in all tissues analyzed. BmSCPx transcription expressed only in midgut and malpighian tubules. However, the BmSCPx and BmSCP2 express strong in midgut during the last instar larvae. The tissue-specific expression pattern of BmSCPx and BmSCP2 is consistent with a role for these proteins in cholesterol metabolism. The results suggest that SCPx/SCP2 may play a key role in sterol absorption and intracellular carrier in silkworm.

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Section: Discussionmentioning

confidence: 99%

Molecular cloning and characterization ofBombyx moristerol carrier protein x/sterol carrier protein 2 (SCPx/SCP2) gene

et al. 2006

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“…(2)]. In the more versatile insect system, the same basic Lp particle carries a wide variety of lipids and selectively delivers specific lipids to specific tissues, e.g., cholesterol to oocytes (13,27) and fat body (27), hydrocarbons to the cuticle (7), and carotenoids to the cuticle or the silk gland, etc. (28).…”

Section: Discussionmentioning

confidence: 99%

Lipid transfer particle mediates the delivery of diacylglycerol from lipophorin to fat body in larval Manduca sexta

Canavoso

Yun

Jouni

et al. 2004

Journal of Lipid Research

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In insects, the majority of stored lipids are found in the fat body, an organ analogous to vertebrate adipose tissue and liver. In Manduca sexta , triacylglycerol (TAG) constitutes more than 90% of the fat body lipids, whereas diacylglycerol (DAG) accounts for less than 2-3%. TAG is derived mainly from dietary fat, which is transferred in the form of DAG by lipophorin from the midgut to the fat body during the feeding stage. A minor source of TAG in the fat body is the de novo lipid synthesis from carbohydrates (1). We have shown recently that the uptake of DAG from midgut to lipophorin takes place by the action of lipid transfer particle (LTP) (2).LTP is a very high density lipoprotein, first purified from the hemolymph of larval M. sexta (3) [see also refs. (4, 5) for recent reviews]. LTP has also been identified in the hemolymph of Locusta migratoria (6), Periplaneta americana (7), Musca domestica (8), and Bombyx mori (9). LTP is synthesized in the fat body and secreted into the hemolymph (10). The physiological function of LTP is still not completely understood. The protein catalyzes the transfer of DAG from adult fat body to high density lipophorin (Lp), resulting in the formation of low density lipophorin (LDLp) (11), but not the reverse reaction. LTP catalyzes the transfer of DAG from the larval midgut to Lp, but not the reverse reaction (12), and from Lp to ovarioles (13). LTP also catalyzes the transfer and/or exchange of DAG between Lp or LDLp and vitellogenin (9). The protein also facilitates the transfer of other lipids from Lp to LDLp, including hydrocarbons (7), phospholipids (9), and carotenoids (14), and it catalyzes the exchange and/or transfer of DAG between Lps and human lipoproteins (15).We have been investigating the role of LTP in DAG transfer in larval M. sexta using in vitro assays. In the midgut, LTP is required to export DAG from the midgut to Lp (12). Interestingly, LTP does not catalyze the transfer of DAG from Lp to the midgut. In this paper, we describe the extension of these studies to the larval fat body and show for the first time that LTP is required for the bidirectional transfer of DAG between Lp and fat body.

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“…Processing of dietary phytosterols will involve both assimilation and metabolic de-alkylation, both of which can vary (Knauer et al, 1999;Harvey et al, 1987;Teshima, 1971). Cholesterol and phytosterols are taken up directly by midgut cells in insects (Canovoso et al, 2001;Jouni et al, 2002) and dealkylation of phytosterols then takes place within the midgut cells, rather than in the gut lumen. Sterol assimilation in Calanus helgolandicus is influenced by food concentration, with higher assimilation efficiencies at low food concentrations (Harvey et al, 1987), a pattern also observed by Landry et al (Landry et al, 1984) for carbon and nitrogen assimilation efficiency in C. pacificus.…”

Section: Cholesterol Feeding Growth and Temperaturementioning

confidence: 99%

Habitat temperature is an important determinant of cholesterol contents in copepods

Hassett

Crockett

2009

Journal of Experimental Biology

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SUMMARYEffects of habitat and acclimation temperature on cholesterol contents were examined in oceanic and inshore species of copepods. The cholesterol content of five species of thermally acclimated copepods was determined, and nine species (representing six families) were sampled to assess the role of habitat temperature. The species selected have maximum habitat temperatures (and temperature tolerances) that vary at least twofold. Levels of dietary cholesterol required to achieve maximum growth were also studied at different acclimation temperatures in a eurythermal copepod. Both eggs and copepodites of Calanus finmarchicus had higher cholesterol levels at the warm acclimation temperature (16°C) than at the cooler temperature (6°C). Neither Acartia tonsa, Acartia hudsonica, Temora longicornis nor Eurytemora affinis altered cholesterol contents with acclimation temperature. Maximum growth rates were achieved at fourfold higher concentrations of dietary cholesterol in warm-acclimated Eurytemora affinis than in cold-acclimated animals. The most consistent trend is the positive relationship between cholesterol content and habitat temperature. Species residing in warmer habitats (e.g. Centropages typicus, Eurytemora affinis) had approximately twice the cholesterol of species living in colder waters (e.g. Calanus glacialis, Euchaeta norvegica). A similar pattern was observed for comparisons of species within genera (Calanus, Acartia and Centropages), with the species abundant at lower latitudes having more cholesterol than the northern congener. These data indicate that habitat temperature is an important determinant of cholesterol content, and cholesterol endows membranes with the stability required for a range of body temperatures.

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Absorption and tissue distribution of cholesterol in Manduca sexta

Cited by 43 publications

References 27 publications

Molecular cloning and characterization ofBombyx moristerol carrier protein x/sterol carrier protein 2 (SCPx/SCP2) gene

Molecular cloning and characterization ofBombyx moristerol carrier protein x/sterol carrier protein 2 (SCPx/SCP2) gene

Lipid transfer particle mediates the delivery of diacylglycerol from lipophorin to fat body in larval Manduca sexta

Habitat temperature is an important determinant of cholesterol contents in copepods

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