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The complete sequence of the mitochondrial genome was determined for two cultivars of Brassica rapa . After determining the sequence of a Chinese cabbage variety, 'Oushou hakusai', the sequence of a mizuna variety, 'Chusei shiroguki sensuji kyomizuna', was mapped against the sequence of Chinese cabbage. The precise sequences where the two varieties demonstrated variation were ascertained by direct sequencing. It was found that the mitochondrial genomes of the two varieties are identical over 219,775 bp, with a single nucleotide polymorphism (SNP) between the genomes. Because B. rapa is the maternal species of an amphidiploid crop species, Brassica juncea , the distribution of the SNP was observed both in B. rapa and B. juncea . While the mizuna type SNP was restricted mainly to cultivars of mizuna (japonica group) in B. rapa , the mizuna type was widely distributed in B. juncea . The finding that the two Brassica species have these SNP types in common suggests that the nucleotide substitution occurred in wild B. rapa before both mitotypes were domesticated. It was further inferred that the interspecific hybridization between B. rapa and B. nigra took place twice and resulted in the two mitotypes of cultivated B. juncea .

Intestinal absorption, biliary excretion and metabolism of a calcium gallstone dissolving agent, [11,12-3H]ursodeoxycholyl-N-carboxymethylglycine (UDC-CMG) and its monoethyl, diethyl and dipivaloyloxyethyl esters (UDC-CMG-Et, UDC-CMG-Et2 and UDC-CMG-PV2) were studied in bile duct cannulated rats. Biliary recovery of [3H]-labeled UDC-CMG, UDC-CMG-Et and UDC-CMG-Et2 after intraduodenal administration were 65%, 80%, 98%, respectively. Radio-thin layer chromatography analysis of the bile revealed that UDC-CMG didn't undergo any biotransformation during administration and excretion. About 80% and 20% of radioactivity recovered in the bile was identified as UDC-CMG-Et and UDC-CMG, respectively, after intraduodenal administrations of [3H]UDC-CMG-Et2 and [3H]UDC-CMG-Et. The administered intact UDC-CMG-Et2 was not found in the bile. Intraduodenally administered [3H]UDC-CMG-PV2 was rapidly recovered in the bile. The total recovery rate was 78% within a 24 h period. More than 80% of the radioactivity recovered in the bile was found as UDC-CMG. Lesser amounts of the monopivaloyloxyethyl ester of UDC-CMG were also found, but intact UDC-CMG-PV2 was not detected in the bile as in the case of UDC-CMG-Et2. Among the esters of UDC-CMG investigated in the present studies, only UDC-CMG-PV2 was excreted in the bile mainly as the perhydrolyzed form, UDC-CMG. These results suggest the usefulness of UDC-CMG-PV2 as the pro-drug in calcium gallstone dissolution therapy.

Sarcosine conjugated ursodeoxycholic acid (SUDC) was synthesized and its intestinal absorption and metabolism were studied in rat and hamster. Intestinal absorption study using bile fistula rat shows that more than 90% of SUDC administered intraduodenally was excreted in the bile within 24 hr. No change of the administered bile acid was seen during the absorption from the intestine, the passage of the liver, and the excretion into the bile. When [24-14C]SUDC and [11,12-3H2]-ursodeoxycholic acid were administered orally to a hamster, more than 95% of both the administered 14C and 3H were recovered from the feces within 6 days. Most (77%) of the fecal 14C-labeled compound was SUDC, whereas 95% of the fecal 3H-labeled compound was unconjugated lithocholic acid. These results indicate that SUDC, unlike taurine or glycine conjugated bile acid, resists bacterial deconjugation and 7-dehydroxylation.

From rhizomes of Panax japonicus (Araliaceae), two polysaccharides named tochibanan-A and -B, which show reticuloendothelial-potentiating activity in the carbon clearance test in mice, were isolated. The structure of tochibanan-A (molecular mass: 23,000) was elucidated as a linear beta-1,4-D-galactan. Tochibanan-B (molecular mass: 40,000) consists of D-galactose (87.1%), L-arabinose, D-glucose and D-galacturonic acid and has a beta-D-(1----4)-linked galactopyranosyl backbone possessing GalA-(1----6)-Gal, Ara-(1----5)-Ara, Gal, and Glc side chains. The structure around the branching points and the repeating unit were investigated and a possible structure of tochibanan-B is proposed.