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1.
The following results were obtained: (1) A commercial protease preparation gave the best enantioselective hydrolysis of N-acetyl-dl-methionine methyl ester ( N-Ac-dl-MetOMe) to produce N-Ac-l-Met with >99% e.e. (2) Solid NaHCO 3 prevented chemical hydrolysis of N-Ac-dl-MetOMe. (3) N-Ac-l-Met was produced more efficiently when the pH was maintained at 7 with a mild base. (4) Crystalline N-Ac-l-Met and d-Met were simultaneously obtained with >99% e.e. in 45 and 36% yield, respectively, from the reaction mixture. 相似文献
2.
Lipopolysaccharides (LPS), isolated from four Mycoplana species, i.e. the type strains of M. bullata, M. segnis, M. ramosa and M. dimorpha, were characterized onto their chemical composition and their respective lipid A-types. Those of M. bullata and M. segnis showed on DOC-PAGE an R-type character and had lipid A's of the Lipid A DAG-type which exclusively contained 2,3-diamino-2,3-dideoxy- d-glucose as lipid A sugar. LPS's of M. ramosa and M. dimorpha showed, although only weakly expressed, ladder-like patterns on DOC-PAGE indicating some S-type LPS's and lipid A of the d-glucosamine type (Lipid A GlcN). M. bullata LPS contained mannose and glucose in major amounts and additionally l-glycero- d-mannoheptose, whereas M. segnis LPS was composed of rhamnose, mannose and glucose together with both, d-glycero- d-manno- and l-glycero- d-manno-heptoses in a molar ratio of 1:2. All LPS's contained 2-keto-3-deoxy-octonic acid (Kdo), phosphate and an unidentified acidic component X. In addition to X, M. segnis LPS contained glucuronic and galacturonic acids, whereas M. ramosa LPS contained only galacturonic acid. Acetic acid hydrolysis of the LPS resulted in splitting off lipid A moieties, very rich in 3-hydroxy fatty acids, in particular in 3-OH-12:0 (in Lipid A DAG), or in 3-OH-14:0 (in Lipid A GlcN). Analysis of the 3-acyloxyacyl residues revealed major amounts of amide-linked 3-OH(3-OH-13:0)12:0 in lipid A of M. bullata and 3-OH(12:0)12:0 in lipid A of M. segnis. The rare 4-oxo-myristic acid (4-oxo-14:0) was observed only in M. bullata LPS, where it is ester-linked. Amide linked diesters could not be traced in M. ramosa and M. dimorpha. All four lipid A's lacked erster-bound acyloxyacyl residues.Non-standard abbreviations DAG
2,3-diamino-2,3-dideoxy- d-glucose
- Kdo
2-keto-3-deoxy-octonate
- LPS
lipopolysaccharide
- PITC
phenyl isothiocyanate
- NANA
N-acetyl neuraminic acid 相似文献
3.
A bacterium, Aeromonas sp. GJ-18, having strong chitinolytic activity was isolated from coastal soil and used for crude enzyme preparations. This enzyme preparation contained N-acetyl- D-glucosaminidase and N, N-diacetylchitobiohydrolase. N-Acetyl- D-glucosaminidase was inactive above 50 °C, but N, N-diacetylchitobiohydrolase was stable at this temperature. Utilizing the temperature sensitivities of the chitin degradation enzymes in crude enzyme preparation, N-acetyl- D-glucosamine (GlcNAc) and N, N-diacetylchitobiose [(GlcNAc) 2] were selectively produced from chitin. At 45 °C, GlcNAc was produced as a major hydrolytic product (94% composition) with a yield of 74% in 5 d, meanwhile at 55 °C (GlcNAc) 2 was the major product (86%) with a yield of 35% within 5 d.Revisions requested 29 September 2004; Revisions received 1 November 2004 相似文献
4.
It has been shown that the main components of levorin A, that is, A0, A1, A2, or A3, that contain an aromatic group increase the permeability of membranes in the series A3 > A2 > A1 > A0 when they are on the same side of the membrane. All levorin components have cationic selectivity. The most studied levorin, А2, promotes the almost ideal permeability of membranes to potassium ions. The membrane potential for a ten-fold change in the KCl concentration gradient is 56 ± 2 mV. It has been shown that the injection of the same concentration of levorin А2 into one side of the membrane and then, after achieving the typical membrane permeability, into the other side of the membrane generates a two-fold increase in the total membrane permeability. This means that independent levorin-induced conductive semi-pores are formed on each side of the membrane. It has been found that the injection of levorin А2 only into one side of the membrane enhances the membrane permeability to monosaccharides and other neutral molecules. The presence of levorin А2 in cholesterol-, ergosterol-, and stigmasterol-containing phospholipid membranes has been shown to lead to the single-channel conductivity of typical ion channels of 0.2–0.5 pS. The properties of these channels have been studied. The levorin channels exist in two states, open and closed. Most of the time, the channel remains in the open state in the KBr solution. In solutions of different salts of the same concentration, the conductivity value of the levorin channels is approximately the same (0.4–0.5 pS). An increase in the dimethyl sulfoxide concentration in aqueous solutions facilitates the transition of polyene antibiotic molecules from dispersed to monomolecular form. The molecules of polyene antibiotics in the associated form exhibit high membrane activity. 相似文献
5.
Four strains of Aspergillus niger were screened for lipase production. Each was cultivated on four different media differing in their contents of mineral components
and sources of carbon and nitrogen. Aspergillus niger NRRL3 produced maximal activity (325U/ml) when grown in 3% peptone, 0.05% MgSO 4.7H 2O, 0.05% KCl, 0.2% K 2HPO 4 and 1% olive oil:glucose (0.5:0.5). A. niger NRRL3 lipase was partially purified by ammonium sulphate precipitation. The majority of lipase activity (48%) was located
in fraction IV precipitated at 50–60% of saturation with a 18-fold enzyme purification. The optimal pH of the partial purified
lipase preparation for the hydrolysis of emulsified olive oil was 7.2 and the optimum temperature was 60°C. At 70°C, the enzyme
retained more than 90% of its activity. Enzyme activity was inhibited by Hg 2+ and K +, whereas Ca 2+ and Mn 2+ greatly stimulated its activity. Additionally, the formed lipase was stored for one month without any loss in the activity. 相似文献
6.
The persistence of gibberellin A 3 on plant surfaces was examined using fruit of Marsh seedless grapefruit ( Citrus paradisi Macf.) and an inert glass model system. 14C-gibberellin A 3 was applied to surfaces in aqueous treatment solutions or in waxing solutions. Dried-out treatment residues were removed by washing and analyzed for total and GA 3-like radioactivity. Gibberellin A 3 persisted without significant loss for at least 7 d in aqueous treatment solutions (pH 4.0 or 6.2) but was less persistent in the pH 10.4 waxing solution ( t1/2=7 d).Loss of total peel surface radioactivity was fast during the first 3 days, slowing down afterwards. After 14 days 73% of the initial radioactivity could still be recovered from fruit peel surface and 70% of the recovered radioactivity was still in the form of gibberellin A 3. Gibberellin A 3 was somewhat more persistent in residues from pH 4 than pH 7 treatment solutions. Light had a slight enhancing effect on gibberellin A 3 decomposition on fruit peel under growth chamber conditions. After 12 d at 100% relative humidity, 88% of the radioactivity on glass surfaces was still in the form of gibberellin A 3, as against 45% at a relative humidity of 50%. Simulated field conditions, combining daily fluctuations in light, temperature and relative humidity, markedly enhanced gibberellin A 3 decomposition on glass surfaces ( t1/2=2 d). Gibberellin A 3 was very persistent (90% after 9 d) in the waxing residues on fruit peel surface.Abbreviations GA 3
gibberellin A 3
- RH
relative humidity 相似文献
7.
A solubilized preparation of the major Rhodospirillum rubrum antenna complex (B880) was obtained by a described procedure and its polypeptide composition was analyzed by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. Only two polypeptides of molecular weights close to 7000 were detected after staining the gels with Coomassie brilliant blue. However, several other constituents could be visualized by silver staining or by an immunochemical method. When the preparation was chromatographed on Sephacryl, some of the resulting fractions exhibited the characteristic B880 absorption spectrum and contained only the two proteins that were detectable with Coomassie brilliant blue. In those fractions the A
280/ A
880ratio was 0.4, which indicated a significant improvement of the bacteriochlorophyll to protein ratio over the unchromatographed preparation ( A
280/ A
880=0.7). Other chromatography fractions lacked bacteriochlorophyll and contained a carotenoid which seemed to be bound to protein. The macromolecular constituents present in these latter fractions differed from those associated to the purified B880 complex in their electrophoretic moblities and/or in their staining properties. That suggested the possible existence of a carotenoprotein that did not result from the B880 complex upon loss of bacteriochlorophyll. 相似文献
8.
Gangliosides G M2, G M1 and G D1b were radiolabelled at C-6 of the terminal galactose or N-acetylgalactosamine by the galactose oxidase/[ 3H]NaBH 4 method; gangliosides G M2, G M1, Fuc-G M1 and G D1a were radiolabelled at C-3 of the long chain base by the 2,3-dichloro-5,6-dicyanobenzoquinone/[ 3H]NaBH 4 method.By application of an original HPLC procedure, eight different molecular species were prepared from each labelled ganglioside. Each of these species was characterized by the presence of one of the following long chain bases: erythro C18 sphingosine, threo C18 sphingosine, erythro C18 sphinganine, threo C18 sphinganine, erythro C20 sphingosine, threo C20 sphingosine, erythro C20 sphinganine and threo C20 sphinganine.From G D1b only the species containing the erythro forms of long chain bases were obtained.The individual molecular species were more than 99% homogeneous and had a radiopurity better than 99%. The molecular species of the same ganglioside, radiolabelled at C-3 of the long chain base, had identical specific radioactivity, namely 1.17, 1.25, 0.85 and 1.28 Ci/mmol for G M2, G M1, Fuc-G M1 and G D1a respectively. The molecular species of the same ganglioside, radiolabelled at C-6 of terminal galactose or N-acetylgalactosamine, had similar specific radioactivity, namely 1.34–1.40, 1.44–1.51, 1.37–1.44 Ci/mmol for G M2, G M1 and G D1b respectively. 相似文献
9.
It is a pleasure to contribute to the special issue published in honor of Vladimir Skulachev, a distinguished scientist who greatly contributes to maintain a high standard of biochemical research in Russia. A more particular reason can be found in his work (Artzabanov, V. Y., Konstantinov, A. A., and Skulachev, V. P. (1978) FEBS Lett., 87, 180–185), where observations anticipating some ideas presented in my article were reported. Cytochrome c oxidase exhibits protonmotive, redox linked allosteric cooperativity. Experimental observations on soluble bovine cytochrome c oxidase are presented showing that oxido-reduction of heme a/Cu A and heme a
3/Cu B is linked to deprotonation/protonation of two clusters of protolytic groups, A 1 and A 2, respectively. This cooperative linkage (redox Bohr effect) results in the translocation of 1 H +/oxidase molecule upon oxido-reduction of heme a/Cu A and heme a
3/Cu B, respectively. Results on liposome-reconstituted oxidase show that upon oxidation of heme a/Cu A and heme a
3/Cu B protons from A 1 and A 2 are released in the outer aqueous phase. A 1 but not A 2 appears to take up protons from the inner aqueous space upon reduction of the respective redox center. A cooperative model is presented in which the A 1 and A 2 clusters, operating in close sequence, constitute together the gate of the proton pump in cytochrome c oxidase.Translated from Biokhimiya, Vol. 70, No. 2, 2005, pp. 220–230.Original Russian Text Copyright © 2005 by Papa.This revised version was published online in April 2005 with corrections to the post codes. 相似文献
10.
The biosynthetic steps from gibberellin A 12-aldehyde (GA 12-aldehyde) to C 19-GAs were studied by means of a cell-free system from the embryos of immature Phaseolus vulgaris seeds. Stable-isotope-labeled GAs were used as substrates and the products were identified by gas chromatography-mass spectrometry. Gibberellin A 12-aldehyde was converted to GA 4 via non-hydroxylated intermediates and to GA 1 via 13-hydroxylated intermediates. 13-Hydroxylation took place at the beginning of the pathway by the conversion of GA 12-aldehyde to GA 53-aldehyde. The conversion of GA 20 to GA 5 and GA 6 was also shown but no 2-hydroxylating activity was found. Endogenous GAs from embryos and testas of 17-dold seeds were re-examined by gas chromatography-selected ion monitoring using stable-isotopelabeled GAs as internal standards. Gibberellins A 9, A 12, A 15, A 19, A 23, A 24, and A 53 were identified for the first time in P. vulgaris, in addition to GA 1, GA 4, GA 5, GA 6, GA 8, GA 17, GA 20, GA 29, GA 37, GA 38 and GA 44, which were previously known to occur in this species. The levels of all GAs, except the 2-hydroxylated ones, were greater in the embryos than in the testas. Conversely, the contents of GA 8 and GA 29, both 2-hydroxylated, were much higher in the testas than in the embryos.Abbreviations GA n
gibberellin A n
- GC-MS
gas chromatography-mass spectrometry
- GC-SIM
gas chromatography-selected ion monitoring
- HPLC
high-performance liquid chromatography
- TLC
thin-layer chromatography
-
m/z
ion of mass 相似文献
11.
Pavlovian conditioning in Hermissenda produces a decrease in voltage-dependent (I K,A and I Ca) and Ca 2+-dependent (I K,Ca) currents, and an increase in the action potential (AP) duration in type B-photoreceptors. In addition, synaptic connections between B and A photoreceptors and B photoreceptor and type I interneurons are facilitated. The increase in AP duration, produced by decreasing one or more K + currents, may account for synaptic facilitation. The present study examined this issue by using a mathematical model of the B-photoreceptor and the neurosimulator SNNAP. In the model, decreasing g K,A by 70% increased the duration of the AP in the terminal by 41% and Ca 2+ influx by 30%. However, if the decrease in g K,A was combined with a decrease in g Ca, similar to what has been reported experimentally, the Ca 2+ influx decreased by 54%. Therefore, the concomitant change in I Ca counter-acted the broadening-induced increase in Ca 2+ influx in the synaptic terminal. This result suggests that a spike-duration independent process must contribute to the synaptic facilitation observed following Pavlovian conditioning. 相似文献
12.
Nodules of cowpea plants ( Vigna unguiculata (L.) Walp. cv. Vita 3 : Bradyrhizobium CB756) cultured for periods of 23 d with their root systems maintained in atmospheres containing a range of partial pressures
of O 2 (pO 2; 1–80%, v/v, in N 2) formed and exported ureides (allantoin and allantoic acid) as the major products of fixation at all pO 2 tested. In sub-ambient pO 2 (1 and 2.5%) nodules contained specific activities of uricase (urate: O 2 oxidoreductase; EC 1.7.3.3) and allantoinase (allantoin hydrolyase; EC 3.5.2.5) as much as sevenfold higher than in those
from air. On a cell basis, uninfected cells in nodules from 1% O 2 contained around five times the level of uricase. Except for NAD: glutamate synthase (EC 1.4.1.14), which was reduced in
sub-ambient O 2, the activities of other enzymes of ureide synthesis were relatively unaffected by pO 2. Short-term effects of pO 2 on assimilation of fixed nitrogen were measured in nodules of air-grown plants exposed to subambient pO 2 (1, 2.5 or 5%, v/v in N 2) and 15N 2. Despite a fall in total 15N 2 fixation, ureide synthesis and export was maintained at a high level except in 1% O 2 where formation was halved. The data indicate that in addition to the structural and diffusional adaptations of cowpea nodules
which allow the balance between O 2 supply and demand to be maintained over a wide range of pO 2, nodules also show evidence of biochemical adaptations which maintain and enhance normal pathways for the assimilation of
fixed nitrogen.
This work was supported by a grant from the Australian Research Council (to C.A.A.) and an Australian Development Assistance
Bureau postgraduate fellowship (to F.D.D.). 相似文献
13.
The fermentation process for a poly (L-lactide) (PLA)-degrading enzyme production by a newly isolate of thermophilic PLA-degrading
Actinomadura sp. T16-1 was investigated. The strain produced 33.9 U/mL of enzyme activity after cultivation at 50°C under shaking of 150
rpm for 96 h in a medium consisting of (w/v) 0.05% PLA film, 0.2% gelatin, 0.4% (NH 4) 2SO 4, 0.4% K 2HPO 4, 0.2 % KH 2PO 4, and 0.02% MgSO 4 · 7H 2O. The optimal concentration of PLA film and gelatin obtained by response surface methodology (RSM) for the highest production
of PLA-degrading enzyme was 0.035% (w/v) and 0.238% (w/v), respectively. Under these conditions, the model predicted 40.4
U/mL of PLA-degrading activity and the verification of the optimization showed 44.6 U/mL of PLA-degrading enzymatic activity
in the flasks experiment. The maximum PLA-degrading activity reached 150 U/mL within 72 h cultivation in the 3-L airlift fermenter. 相似文献
14.
目的:检测老年住院患者分离的鲍曼不动杆菌的主要耐药基因,并研究不同耐药基因型与耐药表型之间的对应关系。方法:用PCR方法检测分离自老年住院患者的不同标本来源的170例非重复鲍曼不动杆菌的耐药基因。检测的耐药基因包括D类碳青霉烯酶:bla_(OXA-51),bla_(OXA-23),bla_(OXA-24),bla_(OXA-58),B类金属碳青霉烯酶:bla_(VIM),bla_(IMP),bla_(SIM),bla_(GIM),bla_(DIM),bla_(NDM-1),以及A类超广谱β-内酰胺酶:blaKPC,共计11种。根据检测结果对菌株进行基因分型,并研究不同基因型与CRAB和CSAB这两种耐药表型之间的对应关系。结果:170株鲍曼不动杆菌的固有基因bla_(OXA-51)均为阳性,此外,主要检出基因为bla_(OXA-23),共124株。另外检测出blaKPC12株,bla OXA-58 6株,bla_(NDM-1)3株,bla_(SIM)2株,bla_(OXA-24)、bla_(VIM)和bla_(DIM)各1株,IMP和GIM未检出。根据检出耐药基因的不同组合,分为bla OXA-51+bla_(OXA-23)阳性为基础的A型(124株)及bla_(OXA-23)阴性为基础的B型(bla_(OXA-51),39株)、C型(bla_(OXA-51)+bla_(OXA-58),6株)、D型(bla_(OXA-51)+bla_(OXA-24),1株)共计四类基因型。从耐药表型来看,128株碳青霉烯耐药菌中有122株bla_(OXA-23)为阳性,在CRAB中占95.3%(122/128),42株碳青霉烯敏感株中,有40株bla_(OXA-23)为阴性,在CSAB中占95.2%(40/42)。结论:老年病房流行的耐碳青霉烯鲍曼不动杆菌的耐药基因型以bla_(OXA-23)阳性为主。其与鲍曼不动杆菌CRAB耐药表型、bla_(OXA-23)阴性与CSAB耐药表型之间有良好的对应关系。 相似文献
15.
Castasterone (CS) and brassinolide (BL) were administered to mung bean ( Vigna radiata) explants, Arabidopsis thaliana seedlings, and cultured Catharanthus roseus cells, and the glucosylated metabolites were analyzed using LC/MS/MS. In mung bean and C. roseus, CS-2- O-glucoside (CS-2G), -3- O-glucoside (CS-3G), -22- O-glucoside (CS-22G), and -23- O-glucoside (CS-23G) were identified as metabolites of CS, whereas BL-2G, BL-3G, and BL-23G were identified as metabolites
of BL. In A. thaliana, CS and BL were converted into their respective 2- O- and 23- O-glucosides. Of the metabolites identified with BL and CS administration, BL-23G was the predominant metabolite in mung bean
and A. thaliana, whereas the 3- O-glucoside of BL was abundant in C. roseus. This is the first report of the metabolic conversion of CS into CS-2G, CS-3G, CS-22G, and CS-23G, and of BL into BL-2G and
BL-3G. Our results indicate that the glucosylation profiles of BL and CS vary with plant species, and that the glucosylation
of CS is rather limited quantitatively, compared with that of BL. 相似文献
16.
98.9% of 5092 flowers from 1041 individuals of Circaeaster agrestis have five floral organs, the formula is P 3A 1G 1 (73.13%), P 2A 2G 1 (25.59%), and P 2A 1G 2 (0.22%). Only 0.4% of the flowers have six floral organs and the formula is P 3A 1G 2 (20 flowers) or P 3A 2G 1 (one flower). All these flowers have one vascular bundle in the pedicel and were considered to be normal ones. There are
33 flowers (0.65%) with six or more floral organs and two vascular bundles in the pedicel and we found traces of fusion of
different degree of two flowers into one. These flowers were considered as abnormal. Therefore the normal number of floral
organs of C. agrestis is five and occasionally six, and the floral formulas are P 3A 1G 1 or P 2A 2G 1, sometimes P 2A 1G 2, and occasionally P 3A 1G 2 or P 3A 2G 1. A tepal in P 3A 1G 1 may be replaced by a stamen in P 2A 2G 1 or by a carpel in P 2A 1G 2 or in reverse. A carpel in P 3A 1G 2 may be replaced by a stamen in P 3A 2G 1 or in reverse. We hypothesize that there are two possibilities for the number of the floral organs to be five (six), the
result of reduction from P 3A 2G 2, or there exists homeosis among floral organs. 相似文献
17.
Pseudomonas mendocina strain 0806 was isolated from oil-contaminated soil and found to produce polyesters consisting of medium chain length 3-hydroxyalkanoates (mclPHAs). The monomers of mclPHAs contained even numbers of carbon atoms, such as 3-hydroxyhexanoate (HHx or C 6), 3-hydroxyoctanoate (HO or C 8), and/or 3-hydroxydecanoate (HD or C 10) as major components when grown on many carbon sources unrelated to their monomeric structures, such as glucose, citric acid, and carbon sources related to their monomeric structures, such as myristic acid, octanoate, or oleic acid. On the other hand, PHA containing both even and odd numbers of hydroxyalkanoates (HA) monomers was synthesized when the strain was grown on tridecanoic acid. The molar ratio of carbon to nitrogen (C/N) had a significant effect on PHA composition: the strain produced PHAs containing 97–99% of HD monomer when grown in a glucose ammonium sulfate medium of C/N<20, and 20% HO, and 80% of the HD monomer when growth was conducted in media containing C/N>40. It was demonstrated that the HO/HD ratio in the polymers remained constant in media with a constant C/N ratio, regardless of the glucose concentration. Up to 3.6 g/L cell dry weight containing 45% of PHAs was produced when the strain was grown for 48 h in a medium containing 20 g/L glucose with a C/N ratio of 40. 相似文献
18.
Gene frequencies were investigated in the - Est1 locus between Japanese populations of Panonychus citri occurring on some fruit trees and on the garden trees, Osmanthus trees and Ilex crenata. A new allele, A
3, was found in the - Est1 of populations collected on Osmanthus trees. Populations on I. crenata, Citrus unshiu and Pyrus serotina had one or both A
1 and A
2 alleles. However, the populations on Osmanthus trees had only the A
3 allele and did not vary geographically. 相似文献
19.
The future capacity of forest ecosystems to sequester atmospheric carbon is likely to be influenced by CO 2-mediated shifts in nutrient cycling through changes in litter chemistry, and by interactions with pollutants like O 3. We evaluated the independent and interactive effects of elevated CO 2 (560 μl l −1) and O 3 (55 nl l l −1) on leaf litter decomposition in trembling aspen ( Populus tremuloides) and paper birch ( Betula papyrifera) at the Aspen free air CO 2 enrichment (FACE) site (Wisconsin, USA). Fumigation treatments consisted of replicated ambient, +CO 2, +O 3, and +CO 2 + O 3 FACE rings. We followed mass loss and litter chemistry over 23 months, using reciprocally transplanted litterbags to separate
substrate quality from environment effects. Aspen decayed more slowly than birch across all treatment conditions, and changes
in decomposition dynamics of both species were driven by shifts in substrate quality rather than by fumigation environment.
Aspen litter produced under elevated CO 2 decayed more slowly than litter produced under ambient CO 2, and this effect was exacerbated by elevated O 3. Similarly, birch litter produced under elevated CO 2 also decayed more slowly than litter produced under ambient CO 2. In contrast to results for aspen, however, elevated O 3 accelerated birch decay under ambient CO 2, but decelerated decay under enriched CO 2. Changes in decomposition rates ( k-values) were due to CO 2- and O 3-mediated shifts in litter quality, particularly levels of carbohydrates, nitrogen, and tannins. These results suggest that
in early-successional forests of the future, elevated concentrations of CO 2 will likely reduce leaf litter decomposition, although the magnitude of effect will vary among species and in response to
interactions with tropospheric O 3. 相似文献
20.
Fumonisins were readily produced in cultures of Fusarium moniliforme using a defined liquid medium. Addition of 200 mg of d 3-methyl L-methionine to 100-ml cultures of F. moniliforme gave increased overall yields and high levels of deuterium ( 2H) incorporation into fumonisin B 1. Approximately 90% of the resulting fumonisin B 1 contained 6 deuterium atoms, while 9% of the product contained 3 deuterium atoms. Deuterium was shown to be incorporated exclusively in the methyl groups of the fumonisin backbone. The addition of as little as 5 mg of labeled methionine stimulated fumonisin production, but only about 5% of the fumonisin produced contained 3 deuterium atoms.Abbreviations ELEM
equine leukoencephalomalacia
Mention of companies or products by name does not imply their endorsement by the US Department of Agriculture over others not cited. 相似文献
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