This study determined the vitamin B₁₂ content of six wild edible mushrooms which are consumed by European vegetarians. Zero or trace levels (0.01-0.09 µg/100 g dry weight) of vitamin B₁₂ were determined in porcini mushrooms (Boletus spp.), parasol mushrooms (Macrolepiota procera), oyster mushrooms (Pleurotus ostreatus), and black morels (Morchella conica). By contrast, black trumpet (Craterellus cornucopioides) and golden chanterelle (Cantharellus cibarius) mushrooms contained considerable levels (1.09-2.65 µg/100 g dry weight) of vitamin B₁₂. To determine whether C. cornucopioides or C. cibarius contained vitamin B₁₂ or other corrinoid compounds that are inactive in humans, we purified a corrinoid compound using an immunoaffinity column and identified it as vitamin B₁₂ based on LC/ESI-MS/MS chromatograms.
Vitamin B12 content of various edible shellfish was determined by both Lactobacillus leichmannii ATCC 7830 microbiological and intrinsic factor-chemiluminescence methods. The values determined by the microbiological method were 1.2-19.8 (M/C ratio) fold greater in the shellfish than the values determined by the chemiluminescence method. Vitamin B12 compounds were purified from most eaten shellfish, oyster (M/C, 1.5), mussel (M/C, 1.2), and short-necked clam (M/C, 2.7), and partially characterized. TLC and HPLC patterns of each red-colored vitamin B12 compound (M/C, 1.0-1.2) purified from these shellfish were identical to those of authentic vitamin B12. Although the higher values in the determination of vitamin B12 by the microbiological method may be due to the occurrence of vitamin B12-substitutive compounds, the edible shellfish would be excellent vitamin B12 sources judging from the values (> or = 6 micrograms/100 g) determined by the chemiluminescence method.
Abstract A significant amount of vitamin B12 (52.9±8.9 µg/100 g) was found in the dark muscle of the yellowfin tuna (Thunnus albacares), in comparison to that of the light muscle. A corrinoid compound was purified to homogeneity from the dark muscle and partially characterized. TLC and HPLC patterns of the purified corrinoid compound were identical to those of authentic vitamin B12. These results indicate that dark muscle of the yellowfin tuna would be an excellent source of vitamin B12 for humans and aminals.
Vitamin B(12) contents of various Korean purple laver products were determined with the microbiological vitamin B(12) assay method. Although a substantial amount (133.8 microg/100 g) of vitamin B(12) was found in dried purple laver, seasoned and toasted laver products contained lesser vitamin B(12) contents (about 51.7 microg/100 g). The decreased vitamin B(12) contents in the seasoned and toasted laver products, however, were not due to loss or destruction of vitamin B(12) during the toasting process. Silica gel 60 thin layer chromatography-bioautogram analysis indicated that all Korean laver products tested contain true vitamin B(12), but not inactive corrinoid compounds. In vitro gastrointestinal digestion experiments indicated that digestion rate of vitamin B(12) from the dried Korean purple laver was estimated to be 50% under pH 2.0 conditions (as a model of normal gastric function). These results suggest that Korean purple laver products would be excellent vitamin B(12) sources for humans, especially vegetarians.
Children with autism have difficulties in social
interaction with other people and much attention
in recent years has been directed to robots as therapy
tools. We studied the social interaction between
children with autism and robots longitudinally
to observe developmental changes in their
performance. We observed children at a special
school for six months and analyzed their performance
with robots. The results showed that two
children adapted to the experimental situations
and developed interaction with the robots. This
suggests that they changed their interaction with
the robots from an object-like one into an agentlike
one.
To clarify the physiological function of pseudovitamin B 12 (or adeninylcobamide; AdeCba) in Spirulina platensis NIES‐39, cobalamin‐dependent methionine synthase (MS) was characterized. We cloned the full‐length Spirulina MS. The clone contained an open reading frame encoding a protein of 1183 amino acids with a molecular mass of 132 kDa. Deduced amino acid sequences of the Spirulina MS contained critical residues identical to cobalamin‐, zinc‐, S ‐adenosylmethionine‐, and homocysteine‐binding motifs. The recombinant Spirulina enzyme showed higher affinity for methyladeninylcobamide than methylcobalamin as a cofactor. These results indicate that Spirulina cells can utilize AdeCba synthesized as the cofactor for MS.
