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1.
Euglena gracilis Klebs, Poterioochromonas malhamensis (Pringsheim) Peterfi, Monochrysis lutheri Droop, Isochrysis galbana Parke and Phaeodactylum tricornutum Bohlin are known to release into the medium a substance which binds free vitamin B12. The binder, apparently a glycoprotein, makes vitamin B12 unavailable and inhibits growth of vitamin B12-requiring microorganisms. Culture filtrates of selected marine diatoms, chrysophytes, cryptophytes, dinoflagellates and green algae contained the binder, indicating that binder release was not restricted to any algal group. However the three prokaryotic bluegreens tested do not produce B12-binder. Production is also independent of the nutritional requirements of the donor, being produced by autotrophs and auxotrophs. The binders produced by these marine species have similar properties: they are heat labile; inhibition is not species-specific; it is competitive, being reversed by adding B12. Production increases with density of the culture and is not restricted to stationary or scenescent cells. The marine species tested produced much less B12 than the freshwater Euglena and Poterioochromonas; the inhibition is reversed by 20–50 ng · 1?1 of B12 for marine species which reach moderate densities and by 150–300 ng · 1?1 B12 for the densely growing species. Consequently the binder may affect the growth of B12-requiring species only in environments like the open ocean poor in B12. By contrast, the marine algae produce other inhibitors which are often heat stable and very inhibitory. These inhibitors, being species-specific and less labile, may be more important in affecting the succession of algal species in natural waters. 相似文献
2.
Nathalie Mangel Jared B. Fudge Kuan‐Te Li Ting‐Ying Wu Takayuki Tohge Alisdair R. Fernie Boris Szurek Teresa B. Fitzpatrick Wilhelm Gruissem Herv Vanderschuren 《The Plant journal : for cell and molecular biology》2019,99(6):1047-1065
Vitamin B6 (pyridoxine) is vital for key metabolic reactions and reported to have antioxidant properties in planta. Therefore, enhancement of vitamin B6 content has been hypothesized to be a route to improve resistance to biotic and abiotic stresses. Most of the current studies on vitamin B6 in plants are on eudicot species, with monocots remaining largely unexplored. In this study, we investigated vitamin B6 biosynthesis in rice, with a view to examining the feasibility and impact of enhancing vitamin B6 levels. Constitutive expression in rice of two Arabidopsis thaliana genes from the vitamin B6 biosynthesis de novo pathway, AtPDX1.1 and AtPDX2, resulted in a considerable increase in vitamin B6 in leaves (up to 28.3‐fold) and roots (up to 12‐fold), with minimal impact on general growth. Rice lines accumulating high levels of vitamin B6 did not display enhanced tolerance to abiotic stress (salt) or biotic stress (resistance to Xanthomonas oryzae infection). While a significant increase in vitamin B6 content could also be achieved in rice seeds (up to 3.1‐fold), the increase was largely due to its accumulation in seed coat and embryo tissues, with little enhancement observed in the endosperm. However, seed yield was affected in some vitamin B6‐enhanced lines. Notably, expression of the transgenes did not affect the expression of the endogenous rice PDX genes. Intriguingly, despite transgene expression in leaves and seeds, the corresponding proteins were only detectable in leaves and could not be observed in seeds, possibly pointing to a mode of regulation in this organ. 相似文献
3.
Twelve clones (seven species) representative of centric diatoms dominant in the spring phytoplankton bloom in the Gulf of Maine were isolated and rendered axenic. Genera included were Thalassiosira, Porosira and Chaetoceros. Unlike most centric diatoms studied previously, none of these has an absolute requirement for vitamin B12. However, B12 (5 ng.l-1) stimulated growth of most clones by eliminating or reducing the lag phase and increasing the growth rate. Bloom population densities developed 4–54 days earlier with B12 present. Several clones grown with B12 removed more than 80% of the vitamin from the medium. When grown in vitamin-free medium the cells put 0.01–0.7 ng.l-1 B12 into the medium. We conclude that vitamin B12 is of ecological significance even though the requirement for it is not absolute. 相似文献
4.
Ernest G. Pringsheim 《Journal of phycology》1975,11(Z1):1-7
All the described species and varieties of the genus Haematococcus were available. After isolation in pure culture they were used studying their nutritional requirements. H. buetschlii and H. droebakensis had already been shown by Droop to need vitamin B12. H. capensis typ., H. capensis var. borealis, and H. zimbabwiensis were found to do so also. The 7 strains of H. pluvi-alis from various localities investigated showed slight physiological deviations, although morphologically they were so similar that they should not be described as varieties. A dilute inorganic nutrient solution with trace elements and iron kept in solution by EDTA was suitable either as such or supplemented with growth-promoting compounds. The growth was speeded by low concentrations of acetate and by enhancing photosynthesis. No strain of H. pluvialis absolutely required cobalamin, although it stimulated. Thiamine had a much more pronounced effect; for some strains it was indispensable. Although the response varies slightly from strain to strain, a luxuriant growth for all was obtained only with acetate and B1, and usually enhanced by B12. A peculiar feature of H. pluvialis is the catching up of cultures initially retarded by thiamine deficiency (probably due to slow Bl synthesis). When H. pluvialis multiplied fast its appearance differed from that considered typical: no red pigment and the cell wall not inflated. In nature it evidently lives under conditions unfavorable for good growth although suitable for survival in competition with other organisms. 相似文献
5.
Raschke M Boycheva S Crèvecoeur M Nunes-Nesi A Witt S Fernie AR Amrhein N Fitzpatrick TB 《The Plant journal : for cell and molecular biology》2011,66(3):414-432
Vitamin B6 is an essential nutrient in the human diet derived primarily from plant sources. While it is well established as a cofactor for numerous metabolic enzymes, more recently, vitamin B6 has been implicated as a potent antioxidant. The de novo vitamin B6 biosynthesis pathway in plants has recently been unraveled and involves only two proteins, PDX1 and PDX2. To provide more insight into the effect of the compound on plant development and its role as an antioxidant, we have overexpressed the PDX proteins in Arabidopsis, generating lines with considerably higher levels of the vitamin in comparison with other recent attempts to achieve this goal. Interestingly, it was possible to increase the level of only one of the two catalytically active PDX1 proteins at the protein level, providing insight into the mechanism of vitamin B6 homeostasis in planta. Vitamin B6 enhanced lines have considerably larger vegetative and floral organs and although delayed in pre‐reproductive development, do not have an altered overall morphology. The vitamin was observed to accumulate in seeds and the enhancement of its levels was correlated with an increase in their size and weight. This phenotype is predominantly a consequence of embryo enlargement as reflected by larger cells. Furthermore, plants that overaccumulate the vitamin have an increased tolerance to oxidative stress providing in vivo evidence for the antioxidant functionality of vitamin B6. In particular, the plants show an increased resistance to paraquat and photoinhibition, and they attenuate the cell death response observed in the conditional flu mutant. 相似文献
6.
Ernest G. Pringsheim 《Journal of phycology》1966,2(1):1-7
All the described species and varieties of the genus Haematococcus were available. After isolation in pure culture they were used studying their nutritional requirements. H. buetschlii and H. droebakensis had already been shown by Droop to need vitamin B12. H. capensis typ., H. capensis var. borealis, and H. zimbabwiensis were found to do so also. The 7 strains of H. pluvialis from various localities investigated showed slight physiological deviations, although morphologically they were so similar that they should not be described as varieties. A dilute inorganic nutrient solution with trace elements and iron kept in solution by EDTA was suitable cither as such or supplemented with growth-promoting compounds. The growth was speeded by low concentrations of acetate and by enhancing photosynthesis. No strain of H. pluvialis absolutely required cobalamin, although it stimulated. Thiamine had a much more pronounced effect; for some strains it was indispensable. Although the response varies slightly from strain to strain, a luxuriant growth for all was obtained only with acetate and B1, and usually enhanced by B12. A peculiar feature of H. pluvialis is the catching up of cultures initially retarded by thiamine deficiency (probably due to slow B1 synthesis). When H. pluvialis multiplied fast its appearance differed from that considered typical: no red pigment and the cell wall not inflated. In nature it evidently lives under conditions unfavorable for good growth although suitable for survival in competition with other organisms. 相似文献
7.
The vitamin B12 requirement of Rhodocyclus purpureus 6770, Rhodospirillum tenue 1/67, and Rhodopseudomonas palustris G 53/2 was determined. A wide variety of biogenetic precursors of the vitamin including cobinamide, cobyric acid, cobinic acid and several partially amidated cobyrinic acids showed growth-promoting activity in all three strains. In R. purpureus vitamin B12 could even be substituted by cobyrinic acid which is the first cobalt-containing precursor of vitamin B12 so far established. Neither methionine, deoxynucleosides, dimethylbenzimidazole nor increased amounts of cobalt could replace vitamin B12 as growth factor.Cupribalamin, which is a strong antimetabolite of vitamin B12 in Escherichia coli 113-3 and Lactobacillus leichmannii ATCC 7830, exhibited only a weak antagonistic effect on growth of R. purpureus and R. tenue. Growth of R. palustris was not inhibited by cupribalamin. The cells of all three strains were shown to contain metal-free corrinoids in addition to cobalt-containing corrinoids. The principal products were identified as 5-deoxyadenosylcobalamin and hydrogenobalamin, the metal free analogue of vitamin B12. The latter does not originate from the vitamin by removal of cobalt but is de novo biosynthesized as could be demonstrated in the case of R. purpureus by a labelling experiment with [13C] methyl-l-methionine. 相似文献
8.
When rabbit serum labelled with vitamin B12[57Co] was subjected to starch gel electrophoresis and au;oradiography, three phenotypes of proteins capable of binding vitamin B12 were observed. Family data revealed that these phenotypes (called TC-A, TC-AB and TC-B) are controlied by two codominant alleles (TCA and TCB), at an autosomic locus. Proteins capable of binding vitamin B12 both in vivo and in vitro are commonly referred to as Transcobalamins and can be found in the serum of numerous animal species (for a review, see Glass, 1974; Allen, 1975; Stenman, 1975). Furthermore, Daiger et al. (1975a) have described seven different patterns of vitamin B12 binding proteins which occur in human plasma and which are presumably controlled by four alleles. The present paper describes experiments in which both starch gel electrophoresis and autoradiography are used to identify three phenotypes of rabbit serum proteins responsible for binding vitamin B12 in vitro. It was found that these three phenotypes are controlled by two allelic codominant genes, at an autosomic locus. Individual serum samples (30 μl), obtained from 385 White New Zealand rabbits varying in age from one month to three years, were incubated with 0.1 ng of vitamin B12[57Co] (specific activity: 180 μCi/μg; Lot 247; Radiochemical Centre, Amersham, England) at 37°C for 30 minutes. Starch gel electrophoresis and autoradiography were performed as described by Geldermann (1970) and Daiger et al. (1975b), respectively. Electrofocusing (pH range 3.5–9.5) was conducted in the 2117 Multiphor apparatus (LKB, Bromma, Sweden) according to the manufacturer's instructions. The resulting pH gradient was measured with a surface pH electrode (Ingold, Zürich, Switzerland). 相似文献
9.
Vitamin-requiring marine algae, Cyclotella nana, Monochrysis lutheri, and Amphidinium carterae, were grown in batch culture with limiting concentrations of vitamin B12, thiamine, and biotin, respectively. Cell numbers, average cell volumes, biomasses, 11CO2 uptake rates, and chlorophyll a contents were determined daily. Maximum 14CO2 uptake rates in most vitamin concentrations were obtained at 2 days with C. nana and M. lutheri and at 4 days with A. carterae after starved cultures were exposed to the vitamin. Radiocarbon uptake rates approximately reflect biomass increases. Cell numbers were proportional to vitamin concentrations when cells were incubated for 2 to 3 more days. Cell sizes varied depending on time of incubation. Chlorophyll a content did not always reflect vitamin concentrations. Maximum carbon assimilation rates (Km) and saturation constants (Ks) determined from 14CO2, uptake rates in different vitamin concentrations during early incubation were higher than when determined from cell number in log phase growth. Dissolved vitamin B12, thiamine, and biotin in many samples of seawaters were in the ranges which influence the growth rate, cell size, and chlorophyll a content of C. nana, M. lutheri, and A. carterae, respectively, in laboratory studies. The effects of vitamins on these algae in situ may be similar. 相似文献
10.
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
11.
The excretion in the urine of 58Co after an oral dose of 58Co vitamin B12 given together with intrinsic factor has been found to be reduced in a number of patients with psoriasis, eczema, and other less common dermatoses. There is a correlation between the abnormality and the extent of the rash. A reduced glomerular filtration rate was found in a few of the patients in whom it was measured, and this must have been responsible, at least in part, for the reduced excretion of vitamin B12 in these patients, but abnormal vitamin B12 excretion also occurred in the absence of impaired renal function. Our evidence is insufficient to show whether malabsorption or increased tissue utilization of vitamin B12 was the explanation in other cases. Certainly a number of patients had steatorrhoea, and in these it is most likely that malabsorption was the major factor. In patients without steatorrhoea a lone malabsorption of vitamin B12 cannot be excluded. A decreased serum concentration of vitamin B12 was found in only one of the patients. 相似文献
12.
Summary Transport of vitamin B12 across the cytoplamic membrane ofEscherichia coli requires the products ofbtuC andbtuD, two genes in thebtuCED operon. The role ofbtuE, the central gene of this operon, was examined. Deletions withinbtuE were constructed by removal of internal restriction fragments and were crossed onto the chromosome by allelic replacement.
In-frame deletions that removed 20% or 82% of thebtuE coding region did not affect expression of the distalbtuD gene. These nonpolar deletions had little effect on vitamin B12 binding (whole cells or periplasmic fraction) and transport. They did not affect the utilization of vitamin B12 or other cobalamins for methionine biosynthesis, even in strains with decreased outer membrane transport of vitamin B12. ThebtuE mutations did not impair adenosyl-cobalamin dependent catabolism of ethanolamine or repression ofbtuB expression. Thus, despite its genetic location in the transport operon, thebtuE product plays no essential role in vitamin B12 transport. 相似文献
13.
J. RUSSEL CAREFOOT 《The Journal of eukaryotic microbiology》1967,14(1):15-18
SYNOPSIS. Vitamin B12, biotin and thiamine requirements of 10 strains of Volvulina steinii and 1 strain of V. pringsheimii were studied. Vitamin B12 is required for growth of both species, thiamine stimulates growth slightly, and biotin has no discernible effect on growth. The minimum concentration of vitamin B12 giving a growth response in V. steinii, strain SC-2, was 10?8 g/ml, and maximum growth response was obtained with 1.1 × 10?7 g/ml. An organic carbon source is required for growth of V. steinii but not of V. pringsheimii. Growth of V. steinii, strain SC-2, occurred in 20 of 21 carbon sources tested. Optimal growth with each carbon source was largely dependent upon pH. Except for pyruvate, acetate, and ethanol, carbon source utilization was light-dependent, and growth in ethanol was reduced in the dark. Isocitric lyase activity was detected in V. steinii grown on acetate medium. 相似文献
14.
Jayanti Sen Sipra Guha-Mukherjee 《In vitro cellular & developmental biology. Plant》1998,34(4):276-280
Summary Cotyledonary nodes, excised cotyledons, and hypocotyl segments of six varieties ofVigna mungo andV. radiata have been tested for their morphogenic potential on media containing a range of hormonal combinations including benzyladenine,
kinetin, thidiazuron (TDZ), and zeatin. Multiple shoots developed on cotyledonary node explants in all varieties tested on
basal medium containing cytokinin. Presence of both the cotyledons, either full or half, resulted in a maximum number of shoots
produced. Shoot bud regeneration was achieved via meristem formation on excised cotyledons on Murashige-skoog basal medium
with B5 vitamins supplemented with TDZ. Mature plants had normal phenotypes.V. mungo var. PS1 andV. radiata var. Pusa 105 were found to be the most responsive varieties for shoot regneration. The histology ofin vitro organogenesis was studied. 相似文献
15.
Kazamia E Czesnick H Nguyen TT Croft MT Sherwood E Sasso S Hodson SJ Warren MJ Smith AG 《Environmental microbiology》2012,14(6):1466-1476
Many algae are auxotrophs for vitamin B12 (cobalamin), which they need as a cofactor for B12‐dependent methionine synthase (METH). Because only prokaryotes can synthesize the cobalamin, they must be the ultimate source of the vitamin. In the laboratory, a direct interaction between algae and heterotrophic bacteria has been shown, with bacteria supplying cobalamin in exchange for fixed carbon. Here we establish a system to study this interaction at the molecular level. In a culture of a B12‐dependent green alga Chlamydomonas nivalis, we found a contaminating bacterium, identified by 16S rRNA analysis as Mesorhizobium sp. Using the sequenced strain of M. loti (MAFF303099), we found that it was able to support the growth of B12‐dependent Lobomonas rostrata, another green alga, in return for fixed carbon. The two organisms form a stable equilibrium in terms of population numbers, which is maintained over many generations in semi‐continuous culture, indicating a degree of regulation. However, addition of either vitamin B12 or a carbon source for the bacteria perturbs the equilibrium, demonstrating that the symbiosis is mutualistic and facultative. Chlamydomonas reinhardtii does not require B12 for growth because it encodes a B12‐independent methionine synthase, METE, the gene for which is suppressed by addition of exogenous B12. Co‐culturing C. reinhardtii with M. loti also results in reduction of METE expression, demonstrating that the bacterium can deliver the vitamin to this B12‐independent alga. We discuss the implications of this for the widespread distribution of cobalamin auxotrophy in the algal kingdom. 相似文献
16.
Kouichi Ohwada 《International Review of Hydrobiology》1973,58(6):851-871
Seasonal cycles of vitamin B12, thiamine and biotin in the water and sediment of Lake Sagami have been studied for two years in 1970 and 1971 at monthly intervals. They were compared with other biological and chemical factors. Sediments were very rich in the three vitamins during the period of study and they were considered to be a vitamin source for the Jake water. In the surface water, fluctuations both of dissolved and particulate forms of the vitamins were found to correspond fairly with the succession of phytoplankton during these years. Particularly, the dissolved vitamin B12 concentration decreased remarkably at the same time that the particulate form increased considerably in the surface water during periods of dominance by diatoms such as Cyclotella sp., Nitzschia acicularis, N. paleacea, N. actinastroides, N. palea, N. sp. and Synedra acus. From the results, the possible importance of vitamin B12 as one of the ecological factors in Lake Sagami was suggested and discussed. 相似文献
17.
Y Thirupathaiah C Swarupa Rani M Sudhakara Reddy L Venkateswar Rao 《World journal of microbiology & biotechnology》2012,28(5):2267-2271
Strain improvement by genetic manipulation or optimization of fermentation conditions for overproduction of vitamin B12 has a drawback due to feed back inhibition. To resist the feed back inhibition by analogues of vitamin B12 in Propionibacterium freudenrechii subsps. shermanii (OLP-5), we have tested with microbially separated B12 analogues from three different strains. Microbial analogues were differentiated from commercially available vitamin B12 by high pressure liquid chromatography and spectrophotometric method. An analogue isolated from NRRL-B-4327 was shown to
increase vitamin B12 concentration from 18.53 ± 0.15 to 31.67 ± 0.58 mg/l in OLP-5 strain. The presence of chemical analogue (ICH2 Co(DH)2 (H2Py)4) increased vitamin B12 production from 16.13 ± 0.15 to 18.53 ± 0.15 mg/l in OLP-5. These findings revealed that addition of B12 analogues in fermentation media have developed strain resistance to feed back inhibition by vitamin B12. 相似文献
18.
《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
19.
The growth rates of 3 species of phytoplankton were found to be dependent on the vitamin B12 concentrations in the media. In batch cultures, the vitamin B12 half-saturation constants and standard errors were 0.39 ± 0.042 μμg/ml for Thalassiosira pseudonana (clone 3H), 1.69 ± 0.24 μμg/ml for Isochrysis galbana, and 2.77 ± 1.65 μμg/ml for Monochrysis lutheri. A chemostat was used to grow T. pseudonana with vitamin B12 as the controlling factor. In the chemostat the yield and standard deviation, 102 ± 21 × 104 cells/μμg vitamin B12, was the same as in the batch culture, 126 ± 13 ± 104 cells/μμg. The chemostat half-saturation constant, 0.26 ± 0.068 μμg/ml vitamin B12, and maximum growth rate were in agreement with those obtained in batch cultures. Vitamin concentrations for maximum growth, rates were greater than those calculated necessary from yield data to give observed population densities similar to those in natural waters. In the sea the effect of vitamin B12 concentration on growth rates may be complicated by low concentrations of other nutrients or the presence of inhibitors. 相似文献
20.
Mariadhas Valan Arasu Ritam Sarkar Balaji Sundara Sekar Vinod Kumar Chelladurai Rathnasingh Jin-dal-rae Choi Hyohak Song Doyoung Seung Sunghoon Park 《Biotechnology and Bioprocess Engineering》2013,18(1):43-51
Vitamin B12 is a complex biomolecule that acts as a cofactor for a variety of enzymes in microbial metabolism. Pseudomonas denitrificans is exclusively used as an industrial strain for the production of vitamin B12 under aerobic conditions. However, only a few strains of Pseudomonas have been reported to possess the capability of producing this vitamin and they are strongly patent-protected. To improve the applicability of the vitamin B12-producing microorganisms, a new isolate was obtained from municipal waste samples and characterized for its biological properties. The new isolate, designated as SP2, was identified to be a Pseudomonas species based on the sequence homology of its 16S rDNA. Pseudomonas species SP2 had essential genes for vitamin B12 synthesis such as cobB and cobQ and produced a similar amount of vitamin B12 (10.6 ± 0.05 μg/mL) as P. denitrificans ATCC 13867 in 24 h flask culture. SP2 grew well under aerobic condition with the maximum specific growth rate (µ max ) of 0.91 ± 0.03/h, but showed a poor growth under micro-aerobic conditions. SP2 was resistant to antibiotics like streptomycin, carbenicillin, ampicillin, cefpodoxime, colistin, nalidixic acid and sparfloxacin. The ability of SP2 to grow faster and produce vitamin B12 under aerobic conditions makes it a promising host for the production of some biochemicals requiring a coenzyme B12-dependent enzyme, such as glycerol dehydratase. 相似文献