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1.
Lipid profile of the spinal cord myelin was studied in normal and vitamin B12 deficient chicks. The significant findings were a reduction in the total galactolipids and an increase in the total phospholipids of myelin in vitamin B12 deficiency. The altered molar ratios of these lipids suggest a relative immaturity of the myelin in this condition. These changes may initiate the degenerative changes in the central nervous system in vitamin B12 deficiency.Vitamin B12 is essential for normal functioning of both the hemopoietic and the nervous system. Sub-acute combined degeneration of the spinal cord is seen both in association with pernicious anemia and in megaloblastic anemia of dietary origin (1,2). Though many biochemical postulates (3, 4) have been advanced to explain the neurological changes, the role of vitamin B12 in maintaining the integrity of myelin is still obscure. So far only in two animal species the monkey (5) and the chick (6) has myelin degeneration been reported in vitamin B12 deficiency. However, in neither of these reports, have changes in the composition of myelin been described. The results of a study in chicks wherein the effects of vitamin B12 on the lipid profile of myelin were investigated are reported here. 相似文献
2.
Naomichi Nishio Makoto Ueda Yoshinori Omae Mitsunori Hayashi Tadashi Kamikubo 《Bioscience, biotechnology, and biochemistry》2013,77(10):2037-2043
The accumulation of vitamin B12 by Bacillus badins grown on hydrocarbon was investigated. The bacterium could assimilate n-alkanes of C11–C18, ethanol, fumarate, α-ketoglutarate and malate. n-Alkanes of C16–C18, were the best for vitamin B12 production. The bacterium utilized well all of the nitrogen sources tested. Above all, ammonium dihydrogen phosphate was the best for the bacteria] growth and vitamin B12 production. Addition of organic nutrients such as malt extract and meat extract, and addition of metal ions such as ferrous and cobalt promoted the growth and vitamin B12 production. Interestingly, vitamin B12 was produced mostly in the supernatant. The cyanoform of the corrinoid predominantly formed in the supernatant would confirm the identity with cobalamin. 相似文献
3.
J. F. Adams 《BMJ (Clinical research ed.)》1970,1(5689):138
The relation between the serum vitamin B12 level and the daily loss of vitamin B12 in urine was examined in patients with normal serum vitamin B12 levels and in patients suffering from vitamin B12 deficiency. A linear correlation was found between the two measurements, suggesting that the serum vitamin B12 level is a governing factor in the urinary loss of vitamin B12. The contribution by this loss to the total loss of vitamin B12 from the body is small under normal circumstances but becomes quantitatively more important with the depletion of body stores. 相似文献
4.
The effect of vitamin B12 and biotin on the metabolism of vitamin B12 in biotin-deficient rats
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1. The effect of the administration of vitamin B12 and biotin on the metabolic pattern of vitamin B12 in biotin-deficient rats was studied. 2. No significant changes in the absorption and excretion of orally administered [58Co]vitamin B12 were noted either in vitamin B12-treated and or in biotin-fed rats. A significant decrease of the uptake of orally given [58Co]vitamin B12 was observed in the liver and kidneys of biotin-treated rats, whereas an increase of uptake in the kidneys of vitamin B12-treated rats was noted as compared with biotin-deficient animals. 3. No significant difference in the excretion of radioactivity was noted between biotin deficient and biotin-fed rats when [58Co]vitamin B12 was administered by injection. A small decrease was observed in vitamin B12-treated rats. The retention of injected [58Co]vitamin B12 by major organs of biotin-treated rats was lower than that of biotin-deficient rats. A lower content of [58Co]vitamin B12 was also detected in the organs, with the exception of the kidneys, of vitamin B12-treated rats. 4. These results are discussed in terms of an interrelationship between biotin and vitamin B12. 相似文献
5.
Free and total vitamin B12 levels in serum and cerebrospinal fluid (CSF) were bioassayed, since there were no available data on the relationship between free and total vitamin B12 in CSF or between free vitamin in serum and CSF vitamin B12. The subjects were 43 neurological patients. Serum levels were normal in 40 of 43 patients. Values for free and total vitamin B12 in CSF were the same in 42 of 43 patients. Mean CSF vitamin B12 was 21 μμg./ml. In 17 cases CSF vitamin B12 equalled free vitamin B12 level in serum, in 16 cases CSF vitamin B12 was lower than the free level in serum, and in 10 cases CSF vitamin B12 was higher than the free vitamin level in serum. There was no apparent diagnostic correlation. The findings suggest that vitamin B12 is not bound in CSF and that there is some selective control of passage of vitamin B12 across the blood-CSF barrier. 相似文献
6.
A third vitamin B12 binding protein present in normal serum has been shown to participate in transport of labelled vitamin B12 absorbed from the gut. All three vitamin B12 binding proteins in serum were labelled at the same time after oral administration of vitamin B12, implying that “free” vitamin B12 reached the portal blood from the gut mucosa. 相似文献
7.
《Archives of animal nutrition》2013,67(2):162-168
Vitamin B12-deficiency may induce specific symptoms as neurological alterations and unspecific symptoms such as anaemia and growth retardation. In this study, maternal vitamin B12 deficiency from end of gestation to weaning was evaluated in mouse dams, which was provoked by feeding a vitamin B12-deficient diet. The animals were divided into two groups (control and deficient). The control group received the vitamin B12-deficient diet supplemented with commercial vitamin B12. Compared to the control, the vitamin B12-deficient dams and their offspring showed a significant decrease of body weight (by 20 and 39%, respectively), serum vitamin B12 concentration (by 61 and 67%, respectively), haematological values as haematocrit (25 and 26%, respectively), and IgA producer cells (by 36 and 54%, respectively). In both, vitamin B12-deficient mouse dams and their offspring, histological alterations of small intestine were observed, whereas growth retardation occurred in the offspring only. This experimental murine model allows assessing the incidence of maternal cobalamin deficiency in offspring and would be useful for evaluating novel adjuncts such as functional foods to prevent vitamin B12 deficiency. 相似文献
8.
《Mycoscience》2014,55(6):462-468
This study determined the vitamin B12 content in commercially available dried fruiting bodies of shiitake mushroom, Lentinula edodes. The vitamin B12 contents in dried donko-type fruiting bodies with closed caps (5.61 ± 3.90 μg/100 g dry weight), did not significantly differ from those of dried koushin-type fruiting bodies with open caps (4.23 ± 2.42 μg/100 g dry weight). The bed logs after fruiting of the mushroom also contained the vitamin B12 levels similar to that in the dried shiitake fruiting bodies. To determine whether the dried shiitake fruiting bodies and their bed logs contained vitamin B12 or other corrinoid compounds that are inactive in humans, we purified corrinoid compounds using an immunoaffinity column and identified vitamin B12 using vitamin B12-dependent Escherichia coli 215 bioautograms and liquid chromatography-electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) chromatograms. Dried shiitake fruiting bodies rarely contained an unnatural corrinoid vitamin B12[c-lactone] that is inactive in humans. Given that shiitake mushroom lacks the ability to synthesize vitamin B12 de novo, the vitamin B12 found in dried shiitake fruiting bodies must have been derived from the bed logs. 相似文献
9.
Mauro Cesar Marghetti Laranjeira Daniel W. Armstrong Faruk Nome 《Bioorganic chemistry》1980,9(3):313-317
The reaction of vitamin B12r, generated by photolysis of methylcobalamin under a nitrogen atmosphere, with 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT), results in extensive dechlorination and formation of 1,1-dichloro-2,2-bis(p-chlorophenyl)ethane (DDD) and 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE) as the major products. Minor quantities of 1,1-bis(p-chlorophenyl)-2-chloroethane (DDMS), 1,1-bis(p-chlorophenyl)-2-chloroethylene (DDMU), 1,1-bis(p-chlorophenyl)ethane (DDO), and 1,1-bis(p-chlorophenyl)ethylene (DDNU) were also formed. Reaction of vitamin B12r with DDD results in the production of DDMU and DDMS, the latter of which can react to produce DDNU and DDO. DDE and DDMU do not react with vitamin B12r. The results obtained are suggestive of a vitamin B12r-mediated dechlorination pathway for polyhalogenated hydrocarbon pesticides. 相似文献
10.
《Bioscience, biotechnology, and biochemistry》2013,77(4):607-610
To study how much the side chains of the corrin ring of vitamin B12 are involved in the physiological roles of the vitamin, five vitamin B12 analogues (cyanocobalamin-b-monocarboxylate, cyanocobalamin-d-monocarboxylate, cyanocobalamin-e-monocarboxylate, cyano-13-epicobalamin, and cyanocobalamin(c-lactam)) with alternations in the side chains were synthesized chemically and then administered orally and intravenously to vitamin B12-deficient rats. Male rats fed a vitamin B12-deficient diet for 11 wk developed a severe vitamin B12 deficiency with a high urinary methylmalonate excretion (223.8 ± 136.2 μmol/d) and ~97% (1.2±0.7ng/g tissue) lower hepatic vitamin B12 content. Oral and intravenous administration of cyanocobalamin-b-,-d-, and -e-monocarboxylates and cyano-13-epicobalamin could not improve the severe vitamin B12-deficient status of the rats, indicating that the b-, d-, and e-propionamide side chains of the corrin ring of vitamin B12 are important in the absorption, transport, and function of the vitamin in rats. Urinary methylmalonate excretion of the rats that were intravenously administered cyanocobalamin(c-lactam) increased twice as much as those of the other analogue-supplemented rats, suggesting that cyanocobalamin(c-lactam) act as a powerful Cbl-antagonist. The results also indicate that mammalian cells do not contain a system for synthesizing complete vitamin B12 from these analogues. 相似文献
11.
Honor M. Kidd 《CMAJ》1965,92(6):261-263
From 25 patients with acute leukemia 116 specimens of leukocytes were assayed microbiologically for total vitamin B12 to determine if variation in vitamin B12 content would help in differentiating the acute leukemias. The mean cell vitamin B12 levels (μμg./108 cells) in the different types of leukemia were: lymphoblastic 464, myeloblastic 1058 and monocytic 200. Cell vitamin B12 levels above the normal range (100-800 μμg./108 cells) are suggestive of myeloblastic leukemia. The only elevated cell vitamin B12 levels comparable to those found in myeloblastic leukemia were in reticulum cell leukemia, and this type of leukemia was not difficult to diagnose morphologically. Blast cells contained more vitamin B12 than mature cells of the same series; there was a significant positive correlation between the percentage of blast cells and cell levels of total vitamin B12 in both lymphoblastic and myeloblastic leukemia. 相似文献
12.
Relatively low concentrations of Vitamin B12 are known to accelerate the anaerobic biotransformation of carbon tetrachloride (CT) and chloroform (CF). However, the addition of vitamin B12 for field-scale bioremediation is expected to be costly. The present study considered a strategy to generate vitamin B12 by addition of biosynthetic precursors. One of the precursors, porphobilinogen (PB) involved in the formation of the corrin ring, significantly increased the CT biotransformation rates by 2.7−, 8.8- and 10.9-fold when supplemented at 160, 500 and 900 μM, respectively. A positive control with 10 μM of vitamin B12 resulted in a 5.9-fold increase in the CT-bioconversion rate. PB additions provided high molar yields of inorganic chloride (57% of CT organochlorine), comparable to that obtained with vitamin B12 supplemented cultures. The primary substrate, methanol, known to induce vitamin B12 production in methanogens and acetogens, was required for PB to have a significant impact on CT conversion. The observation suggests that PB’s role was due to stimulating vitamin B12 biosynthesis. The present study therefore provides insights on how to achieve vitamin B12 enhanced rates of CT bioremediation through the use of less complex compounds that are precursors of vitamin B12. Although PB is a costly chemical, its large impact points to corrin ring formation as the rate-limiting step. 相似文献
13.
《Animal : an international journal of animal bioscience》2019,13(9):2101-2109
As vitamin B12 is only synthesized by bacteria, ruminant products, especially dairy products, are excellent sources of this vitamin. This study aims to identify if diet and cow characteristics could affect vitamin B12 concentration in milk of dairy cows. Information on 1484 first, 1093 second and 1763 third and greater parity Holstein cows in 100 herds was collected during three consecutive milkings. During the first morning milking, all dietary ingredients given to cows were sampled and quantities offered were recorded throughout the day. Nutrient composition of ingredients was obtained by wet chemistry to reconstitute nutrient composition of the ration. Milk samples were taken with in-line milk meters during the evening milking of the 1st day and the morning milking of the 2nd day and were analyzed for vitamin B12 concentration. Milk yields were recorded and milk components were separately analyzed for each milking. Daily vitamin B12 concentration in milk was obtained using morning and evening vitamin B12 concentrations weighted with respective milk yield, then divided by daily yield. To decrease the number of interdependent variables to include in the multivariable model, a principal component analysis was carried out. Daily milk concentration of vitamin B12 averaged 3809±80 pg/ml, 4178±79 pg/ml and 4399±77 pg/ml for first, second and third, and greater lactation cows. Out of 11 principal components, six were significantly related to daily milk concentration of vitamin B12 when entered in the multivariable model. Results suggested that vitamin B12 concentration in milk was positively related to percentage of fiber and negatively related to starch as well as energy of the diet. Negative relationships were noted between vitamin B12 concentration in milk and milk yield as well as milk lactose concentration and positive relationships were observed between vitamin B12 concentration in milk and milk fat as well as protein concentrations. The percentages of chopped mixed silage and commercial energy supplement in the diet as well as cow BW were positively related to vitamin B12 in milk and percentages of baled mixed silage, corn and commercial protein supplement in the ration were negatively related to vitamin B12 concentration in milk. The pseudo-R2 of the model was low (52%) suggesting that diet and cow characteristics have moderate impact on vitamin B12 concentration in milk. Moreover, when entering solely the principal component related to milk production in the model, the pseudo-R2 was 46%. In conclusion, it suggests that studied diet characteristics have a marginal impact on vitamin B12 concentration in milk variation. 相似文献
14.
Uma Bhattacharyya A. K. Dasmahapatra A. K. Medda 《Comparative biochemistry and physiology. Part B, Biochemistry & molecular biology》2000,125(4)
Different doses of vitamin B12 (0.25, 0.5, 1, 2 and 4 μg/g, injected intraperitoneally for three consecutive days) altered the activities of mitochondrial-α-glycerophosphate dehydrogenase (α-GPD) and NADP-dependent cytosolic malic enzyme (ME) in the brain of singi fish. The α-GPD activity increased at doses of 0.5, 1, 2 and 4 μg/g vitamin B12. A dose of 0.5 μg/g vitamin B12 induced less activity than higher doses. ME activity increased with 1, 2 and 4 μg/g of vitamin B12/g. The mitochondrial and cytosolic protein content remained unchanged after vitamin B12 administration. Cycloheximide treatment inhibited the vitamin B12-induced increase in α-GPD and ME activity. Thus, vitamin B12 is involved in the induction of some enzymes in fish brain. 相似文献
15.
《Endocrine practice》2010,16(2):205-208
ObjectiveTo estimate the frequency of undiagnosed vitamin B12 deficiency among patients with type 2 diabetes mellitus who had not taken metformin during at least the prior 5 years and to ascertain whether vitamin B12 deficiency among the patients with type 2 diabetes was due to nutritional deficiency or malabsorption.MethodsSerum vitamin B12 levels were measured in 44 subjects with diabetes and a mean age of 51 years (range, 40 to 70), 21 (48%) of whom had low levels (< 200 pg/mL). Of those 21 patients, 10 agreed to enroll in an intervention phase consisting of oral supplementation with mecobalamin, 1,500 μg daily for 3 months. Those patients in whom vitamin B12 levels failed to normalize after oral supplementation alone would be presumed to have vitamin B12 deficiency attributable to malabsorption.ResultsAlmost half of the subjects with type 2 diabetes not taking metformin had biochemically proven vitamin B12 deficiency. All 10 subjects who enrolled in the intervention phase had normalization of their vitamin B12 levels after 3 months of oral supplementation with mecobalamin.ConclusionWe conclude that vitamin B12 deficiency is common among patients with type 2 diabetes and was related to nutrition in our study group. In addition to intensive glycemic control, vitamin B12 supplementation should be considered for treatment of diabetic neuropathy. In almost 50% of patients with low vitamin B12 levels, the deficiency was corrected with oral supplementation only. This, indeed, is an important finding, inasmuch as oralvitamin B12 supplementation is easy, convenient, and readily accepted by patients. This finding highlights the need for aggressive and early diagnosis and treatment to avoid complications of vitamin B12 deficiency. (Endocr Pract. 2010;16:205-208) 相似文献
16.
Takahiro Shiga Yoshifumi Kimira Hiroshi Mano Tetsunori Kawata Tadahiro Tadokoro Tsukasa Suzuki 《Bioscience, biotechnology, and biochemistry》2016,80(3):510-513
Vitamin B12 deficiency is a risk factor for bone disorders via mechanisms not fully understood. In this study, an increase in serum inorganic phosphorus (Pi) concentrations was associated with a vitamin B12 deficiency. Napi2a, a renal cotransporter for Pi reabsorption, accumulated on plasma membranes in a vitamin B12 deficiency suggests that vitamin B12 plays an important role in Pi homeostasis. 相似文献
17.
D. Glenn Kennedy W. John Blanchflower Paul B. Young W. Brian Davidson 《Biological trace element research》1992,35(2):153-166
The first development of an α-face-specific radioimmunoassay for vitamin B12 is described. Sheep, fed a cobalt-deficient diet, and immunized with a conjugate between Co-β carboxypropyl cobalamin and
keyhole limpet hemocyanin, were used to produce antisera. The antisera crossreacted with Co-β derivatives of vitamin B12, but did not crossreact with the α-face vitamin B12 analog cobinamide. The antisera were used to develop a sensitive and reproducible radioimmunoassay that was free from contamination
with the nonspecific vitamin B12 binding protein, R-protein. Both the radioimmunoassay and measurements of plasma concentrations of methylmalonic acid were
applied to the diagnosis of cobalt/vitamin B12 deficiency in sheep. The assay correlated well with a commercially available radioassay and did not falsely detect normal
vitamin B12 concentration in plasma samples containing elevated concentrations of methylmalonic acid. 相似文献
18.
Virginia Brothers Barbara ONeill Rowley Theo Gerritsen 《Archives of biochemistry and biophysics》1975,166(2):475-482
The effects of vitamin B12 deficiency in rats and dietary supplementation with vitamin B12 and/or l-methionine plus folate on the oxidation of compounds metabolized through folate coenzyme pathways were investigated. Rats fed a vitamin B12-deficient diet oxidized significantly lower amounts in 60 min of l-histidine, glycine, sarcosine, formate, and l-serine to CO2 than vitamin B12-supplemented controls. Supplementation of the deficient diet with l-methionine plus folate restored the ability to oxidize the ring-2-carbon of l-histidine, the methyl group of sarcosine, and formate to the same level as that observed in animals receiving vitamin B12. In contrast, oxidation of the 1-carbon of glycine and the 3-carbon of l-serine was not restored to control levels by addition of methionine plus folate to the vitamin B12-deficient diet. Inhibition of the metabolism of the 2-carbon of glycine to CO2 was partially overcome by additional dietary methionine and folate. Glycine synthase activity in homogenates paralleled the in vivo pattern of oxidation of the 1-carbon of glycine to CO2, whereas sarcosine dehydrogenase activity appeared to increase 2-fold in vitamin B12 deficiency. 相似文献
19.
Charles H. Tan Steven J. Blaisdell Hans J. Hansen 《Biochimica et Biophysica Acta (BBA)/General Subjects》1973,320(2):469-477
The mechanism of the clearance of vitamin B12 from the serum transcobalamin II-vitamin B12 (Tc-II-B12) complex and the reappearance of free Tc-II in mouse have been studied. When a saturating dose of vitamin B12 is given parenterally to normal mice, a portion of the Tc-II-bound vitamin B12 is rapidly cleared and free Tc-II promptly reappears until it reaches a constant level in 6–8 h. The remaining vitamin B12 is cleared slowly from the rest of the Tc-II-B12 complex. In cycloheximide or puromycin-treated mice, free Tc-II fails to reappear and the bound Tc-IIdecreases. Treatment with actinomycin D has no effect on the reappearance of free Tc-II. The probable mechanism of this inhibition is discussed. The results suggest that mouse serum Tc-II has a stable messenger RNA template and a fast turnover. The free Tc-II which reappears in the serum after Tc-II has been saturated with vitamin B12, appears to be newly synthesized. 相似文献
20.
Hidetaka Hatanaka Enhao Wang Masayuki Taniguchi Shinji Iijima Takeshi Kobayashi 《Applied microbiology and biotechnology》1988,27(5-6):470-473
Summary To improve the microbial production of vitamin B12, we applied a hollow-fiber module to cultivation of the vitamin producers. By the removal of growth inhibitors, very high concentrations of cells and vitamin B12 were obtained comparing to the batch culture. We obtained 227 g dry cells/l and 52 mg vitamin B12/l with Propionibacterium shermanii and 33.4 g dry cell/l and 92.5 mg vitamin B12/l with Butyribacterium methylotrophicum by this cultivation. 相似文献