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1.
The level of gibberellin(GA)-like material in cotyledons of soybean (Glycine max L.) was highest at mid-pod fill—about 10 nanograms GA3 equivalents per gram fresh weight of tissue, assayed in the immersion dwarf rice bioassay. This amount is about 1000-fold less than levels in Pisum and Phaseolus seed, other legume species whose spectrum of endogenous gibberellins (GAs) is well known. The metabolism of [14C]-GA12-7-aldehyde (GA12ald)—the universal GA precursor—by intact, mid-pod-fill, soybean cotyledons and their cell-free extracts was investigated. In 4 hours, extracts converted GA12ald to two products—[14C]GA12 (42% yield) and [14C]GA15 (7%). Within 5 minutes, intact embryos converted GA12ald to [14C]GA12 and [14C]GA15 in 15% yield; 4 hour incubations afforded at least 22 products (96% total yield). The putative [14C]GA12 was identified as a product of [14C]GA12ald metabolism on the basis of co-chromatography with authentic GA12 on a series of reversed and normal phase high pressure liquid chromatography (HPLC) and thin-layer chromatography (TLC) systems, and by a dual feed of the putative [14C]GA12 and authentic [14C]GA12 to cotyledons of both peas and soybeans. The [14C]GA15 was identified as a metabolite of [14C]GA12ald by capillary gas chromatography (GC)-mass-spectrometry-selected ion monitoring, GC-radiocounting, HPLC, and TLC. By adding the [14C] metabolites of [14C]GA12ald to a different and larger extract (about 0.2 kg fresh weight of soybean reproductive tissue) and purifying endogenous substances co-chromatographing with these metabolites, at least two GA-like substances were obtained and one identified as GA7 by GC-mass spectrometry. Since [14C]GA9 was not found as a [14C]metabolite of [14C]GA12ald, soybean embryos might have a pathway for biosynthesis of active, C-19 gibberellins like that of the cucurbits; GA12ald → GA12 → GA15 → GA24 → GA36 → GA4 → GA7.  相似文献   

2.
The orthorhombically crystallizing salts Rb2[B12(OH)12]·2H2O (= 1576.81(9), b = 813.08(5), c = 1245.32(7) pm) and Rb2[B12(OH)12]·2H2O2 (= 1616.54(9), b = 814.29(5), c = 1260.12(7) pm) could be prepared from Rb2[B12H12] and hydrogen peroxide. Both crystal structures were determined by X-ray single crystal diffraction and refined in the space group Cmce. They are not isostructural to the other compounds containing icosahedral dodecahydroxo-closo-dodecaborate dianions [B12(OH)12]2− and potassium, rubidium or cesium cations already known to literature, but both title compounds crystallize quasi-isotypically exhibiting Rb+ cations in 10-fold oxygen coordination. The hydrogen peroxide adduct (Rb2[B12(OH)12]·2H2O2) is explosive on shock and heat, while the hydrate (Rb2[B12(OH)12]·2H2O) is not.  相似文献   

3.
A new aluminoborate, [C5H6N][AlB12O14(OH)12], has been hydrothermally synthesized at 200 °C. The single-crystal diffraction study reveals that it crystallizes in space group C2/c. It consists of aluminoborate clusters [AlB12O14(OH)12] and counterions [C5H6N]+. The aluminoborate cluster contains an Al(OH)6 octahedron as a core that is capped by two raft-like polyborate units [B6O7(OH)6]. These clusters are further interlinked by extensive hydrogen bonding to form a three-dimensional (3D) network, containing large channels along the b-axis, in which the [C5H6N]+ cations are located.  相似文献   

4.
3-(D-erythro-Glycerol-1-yl)-1H-pyrazolo[3,4-b]quinoxaline and its 7-chloro and 7-methyl analogues (11 and 12) were prepared from the corresponding quinoxalines. The 7-substituted analogues 11 and 12 were obtained as the preponderant isomers, and the 6-substituted analogues as the minor isomers. The structure and position of the substituent were determined by 1H NMR studies. The effect of substitution on the chemical shift of other protons is discussed.  相似文献   

5.
A variant form of Escherichia coli ribosomal protein L7/L12 that lacked residues 42 to 52 (L7/L12 Δ42–52) in the hinge region was shown previously to be completely inactive in supporting polyphenylalanine synthesis although it bound to L7/L12 deficient core particles with the normal stoichiometry of four copies per particle (Oleinikov AV, Perroud B, Wang B, Traut RR (1993) J Biol Chem, 268, 917–922). The result suggested that the hinge confers flexibility that is required for activity because the resulting bent conformation allows the distal C-terminal domain to occupy a location on the body of the large ribosomal subunit proximal to the base of the L7/L12 stalk where elongation factors bind. Factor binding to the hinge-truncated variant was tested. As an alternative strategy to deleting residues from the hinge, seven amino acid residues within the putative hinge region were replaced by seven consecutive proline residues in an attempt to confer increased rigidity that might reduce or eliminate the bending of the molecule inferred to be functionally important. This variant, L7/L12: (Pro)7, remained fully active in protein synthesis. Whereas the binding of both factors in ribosomes containing L7/L12:Δ42–52 was decreased by about 50%, there was no loss of factor binding in ribosomes containing L7/L12:(Pro)7, as predicted from the retention of protein synthesis activity. The factor:ribosome complexes that contained L7/L12:Δ42–52 had the same low level of GTP hydrolysis as the core particles completely lacking L7/L12 and EF-G did not support translocation measured by the reaction of phe-tRNA bounds in hr Asite with puromycin. It is concluded that the hinge region is required for the functionally productive binding of elongation factors, and the defect in protein synthesis reported previously is due to this defect. The variant produced by the introduction of the putative rigid Pro7 sequence retains sufficient flexibility for full activity.  相似文献   

6.
Two new reciprocal translocations in the German cockroach have been analyzed. They were identified cytologically to be T(3;12) and T(7;12). Linkage studies showed that groups XI, IX, and IV are on chromosomes 12, 3, and 7, respectively, and clearly demonstrated sex differences in recombination. Each of these chromosomes have distinctive morphological features that facilitate their identification, and permit breakpoint and centromere localization. A sex difference in fecundity is associated with T(7;12), but not T(3;12). About 40 percent mortality occurred when T(3;12) males or females and T(7;12) females were outcrossed. Outcrossing T(7;12) males produced the expected 50 percent mortality. Cell counts at metaphase I revealed that T(3;12) males exhibit directed segregation, while T(7;12) males do not. Tests for homozygosity indicated that the T(7;12) homozygote is viable. A map of chromosome 12 is presented showing the tentative placement of linkage group XI with respect to interchange breakpoints and chromosome morphology. The results are discussed in relation to possible sex differences in chiasma localization.  相似文献   

7.
The corrinoids from the obligate anaerobe Clostridium cochlearium were extracted as a mixture of Co(beta)-cyano derivatives. From 50 g of frozen cells, approximately 2 mg (1.5 micromol) of B(12) derivatives was obtained as a crystalline sample. Analysis of the corrinoid sample of C. cochlearium by a combination of high-pressure liquid chromatography and UV-Vis absorbance spectroscopy revealed the presence of three cyano corrinoids in a ratio of about 3:1:1. The spectroscopic data acquired for the sample indicated the main components to be pseudovitamin B(12) (Co(beta)-cyano-7"-adeninylcobamide) (60%) and factor A (Co(beta)-cyano-7"-[2-methyl]adeninylcobamide) (20%). Authentic pseudovitamin B(12) was prepared by guided biosynthesis from cobinamide and adenine. Both pseudovitamin B(12) and its homologue, factor A, were subjected to complete spectroscopic analysis by UV-Vis, circular dichroism, mass spectrometry, and by one- and two-dimensional (1)H, (13)C-, and (15)N nuclear magnetic resonance (NMR) spectroscopy. The third component was indicated by the mass spectra to be an isomer of factor A and is likely (according to NMR) to be 7"-[N(6)-methyl]-adeninylcobamide, a previously unknown corrinoid. C. cochlearium thus biosynthesizes as its native "complete" B(12) cofactors the 7"-adeninylcobamides and two homologous corrinoids, in which the nucleotide base is a methylated adenine.  相似文献   

8.
This report describes the chemical synthesis of six new bile acid analogs, namely, 3 alpha,7 alpha,12 alpha-trihydroxy-7 beta-methyl-5 beta-cholanoic acid (7 beta-methyl-cholic acid), 3 alpha,7 beta,12 alpha-trihydroxy-7 alpha-methyl-5 beta-cholanoic acid (7 alpha-methyl-ursocholic acid), 3 alpha,12 alpha-dihydroxy-7 xi-methyl-5 beta-cholanoic acid (7 xi-methyl-deoxycholic acid), 3 alpha,12 alpha-dihydroxy-7-methyl-5 beta-chol-7-en-24-oic acid, 3 alpha,12 alpha-dihydroxy-7-methyl-5 beta-chol-6-en-24-oic acid, and 3 alpha,12 alpha-dihydroxy-7-methylene-5 beta-cholan-24-oic acid. The carboxyl group of the starting material 3 alpha,12 alpha-dihydroxy-7-oxo-5 beta-cholanoic acid was protected by conversion to its oxazoline derivative. A Grignard reaction of the bile acid oxazoline with CH3MgI followed by acid hydrolysis gave two epimeric trihydroxy-7-methyl-cholanoic acids and three dehydration products. The latter were purified by silica gel column chromatography and silica gel-AgNO3 column chromatography of their methyl ester derivatives. Catalytic hydrogenation of 3 alpha,12 alpha-dihydroxy-7-methyl-5 beta-chol-6-en-24-oic acid and 3 alpha,12 alpha-dihydroxy-7-methylene-5 beta-cholan-24-oic acid gave 3 alpha,12 alpha-dihydroxy-7 xi-methyl-5 beta-cholanoic acid. The configuration of the 7-methyl groups and the position of the double bonds were assigned by proton nuclear magnetic resonance spectroscopy and the chromatographic and mass spectrometric properties of the new compounds. These compounds were synthesized for the purpose of exploring new and potentially more effective cholelitholytic agents. The hydrophilic bile acids 7 beta-methyl-cholic acid and 7 alpha-methyl-ursocholic acid are of particular interest because they should be resistant to bacterial 7-dehydroxylation.  相似文献   

9.
An 8-year-old boy presenting with hypotonia, moderate mental retardation, developmental delay, and psychomotor retardation is reported. Magnetic resonance imaging of the brain at age 3 years revealed a Dandy-Walker variant. Cytogenetic analysis of the peripheral blood revealed a derivative chromosome 12 with unknown additional material attached to the distal region of the long arm of chromosome 12. The parental karyotypes were normal. Spectral karyotyping (SKY) using the 24-color SKY probes and fluorescence in situ hybridization (FISH) using the specific 7p, 7q, 12p, and 12q telomeric probes confirmed a duplication of distal 7p and a deletion of terminal 12q. The karyotype of the proband was designated as 46,XY.ish der(12)t(7;12) (p21.2;q24. 33)(SKY+, 7pTEL+, 12qTEL-). The present case provides evidence for the association of partial trisomy 7p (7p21.2-->pter) and partial monosomy 12q (12q24.33-->qter) with a cerebellar malformation and the usefulness of SKY and FISH in the identification of a de novo aberrant chromosome resulting from an unbalanced translocation.  相似文献   

10.
By introducing various amino methyl groups into 12-position of berberrubine, a series of 12-(substituted aminomethyl) berberrubine derivatives were synthesized and evaluated for their anti-diabetic activity against type 2 diabetes mellitus. The results indicated that most of the prepared compounds exhibited moderate to good anti-diabetic activity, which were comparable to or even better than the berberine, the positive control rosiglitazone and insulin. Especially, compound 3b with an N-methyl piperazine-4-methyl group at C-12, exerted the most powerful anti-diabetic activity.  相似文献   

11.
An effective synthetic method for polyhydroxylated azepanes that contain an alkyl group (Me or Bu) at either the 7- or N-positions is developed. The synthetic routes are accomplished in eight to ten steps from d-(−)-quinic acid. Among the compounds synthesized, the polyhydroxy 7-butyl azepane (compound 3), which possessed the R-configuration at C-7 position, is shown to give potent inhibition against β-galactosidase (IC50 = 3 μM). Preliminary biological data indicate that the length of alkyl groups along with the proper stereochemistry at the C-7 position is essential for acquiring extra binding affinity. Using similar synthetic routes, the polyhydroxy N-methyl and N-butyl azepanes are synthesized for the comparison of their biological activities.  相似文献   

12.
The corpus luteum inhibiting properties of eighteen 15-methyl prostaglandin analogs were determined in the rhesus monkey during concomitant stimulation of the corpus luteum with chorionic gonadotropin. The methyl ester of (15S)-15-methyl PGF2α (15M-PGF2α, 12.5 mg/monkey) lowered serum progesterone to 12% of pretreatment values within 24 hours, however progesterone returned to normal limits within 48 hours. Elongation of the top side-chain by two carbons (2a,2b-dihomo-15M-PGF2α methyl ester, 13 mg/monkey), substitution of a hydroxymethyl group at carbon 1 (2-decarboxy-2-hydroxymethyl-15M-PGF2α, 12 mg/monkey), or the formation of the carbon 1 amide (15M-PGF2α amide, 12.5 mg/monkey) improved the inhibitory activity of 15M-PGF2α; serum progesterone for these 3 analogs was depressed to 15–30% of pretreatment levels within 24 hours, and did not return to control values. Luteal function was not inhibited (12 or more mg/monkey) when the 15-methyl group was placed in the R configuration, the top side chain was shortened by two carbons, an amino group was substituted for carbon 1, the 5-oxa modification was added, or the 1,9-lactone was formed. Some other modifications of 15M-PGF2α were also inactive, although not all were tested at equivalent doses: 2,2-difluoro; 4,5-cis-didehydro; 9,11-dideoxy-9α,11α-dichloro; 11-deoxy; 17-phenyl; 1,15-lactone; and the p-benzamidophenyl ester of 2a,2b-dihomo-15M-PGF2α. (15S)-15-Methyl PGE2 methyl ester (1 mg/monkey) depressed serum progesterone concentrations to 42% of pretreatment values within 24 hours; 2a,2b-dihomo-11-deoxy-(15S)-15-methyl PGE2 methyl ester was inactive (5 mg/monkey). A corpus luteum inhibiting action of certain 15-methyl prostaglandins can be demonstrated in the rhesus monkey.  相似文献   

13.
A computer analysis revealed that the mononucleotide repeat (A)n-(T)n is about five times as common as (CA)n-(GT)n repeats in the porcine genome, with frequency estimates of one every 7kb and 30kb, respectively. Seven mononucleotide repeats with n= 12–25 located close to coding sequences were analysed for polymorphism using polymerase chain reaction (PCR) amplification and polyacrylamide gel electrophoresis. All loci were variable with 3–6 alleles and heterozygosities of 0.26–0.69 based on investigation of 10 unrelated pigs (two wild boars and eight domestic sows). Repeat length correlated with degree of polymorphism. A comparison with (CA)n-(GT)n polymorphisms suggested that the number of repeat units rather than the total length of the repeat region is the common denominator that governs polymorphism at both mono- and dinucleotide repeat loci. (A)n-(T)n polymorphisms allowed linkage mapping of relaxin to chromosome 1, apolipoprotein B to chromosome 3, aminopepti-dase N to chromosome 7, arachidonate 12-lipoxygenase to chromosome 12, and follistatin to chromosome 16. The rich abundance of potentially informative (A)n-(T)n repeats will increase the chances of finding a PCR-based marker near any DNA sequence of interest.  相似文献   

14.
In this study we present a 102-year old woman carrying a (7;12)(q11.3;q14) translocation. A woman displays a normal phenotype and infertility in anamnesis. This is the first report linking t(7;12) and infertility.  相似文献   

15.
Context: Characterization of the pro-oxidant activity of QNACR.

Objectives: Reactive oxygen species (ROS) induce cellular damage and represent unique opportunities to kill malignant cells. In this study, we synthesized and evaluated the new compound, (E)-methyl 2-(7-chloroquinolin-4-ylthio)-3-(4-hydroxyphenyl) acrylate (QNACR) as potential pro-oxidative agent against breast cancer.

Methods: Oxidative stress biomarkers such as ROS, thiobarbuturic acid reactive species (TBARs) and different antioxidant enzyme activities were determined in cell lysates.

Results: QNACR showed cytotoxic and more selective effects to tumour MCF7 cells (IC50 < 25 µM) compared to antitumour controls, inducing ROS and TBARs parallel to inhibitions of catalase (CAT), glucose-6-phosphate dehydrogenase (G6PDH) and 6-phosphogluconate dehydrogenase (6PGDH). Longer exposures to QNACR triggered adaptive effects increasing the overall activities of CAT, glutathione reductase, G6PDH and 6PGDH, but eventually the adaptation changes faded and cells died.

Conclusion: QNACR led to remarkable modifications in the oxidative status of tumour cells, proposing this compound as potential alternative for antitumour therapy.  相似文献   

16.
Searching for agents that could be effective in the treatment of cancer, special highlight has focused on the study of numerous plant-derived compounds. We previously demonstrated that anthraquinones (AQs) isolated from a vegetal species: Heterophyllaea pustulata Hook f. (Rubiaceae), such as rubiadin, rubiadin-1-methyl ether, soranjidiol, soranjidiol-1-methyl ether exhibit photosensitizing properties without antecedents as photodynamic agents in malignant cells. In the present study, we investigated the potential role of these AQs as a phototoxic agent against human breast carcinoma using MCF-7c3 cells. All AQs exhibited significant photocytotoxicity on cancer cells at the concentration of 100 μM with 1 J/cm2 light dose, resulting soranjidiol-1-methyl ether in complete cell destruction. The observed cellular killing by photoactivated AQs exhibited close relation with singlet oxygen production, except for soranjidiol-1-methyl ether, where cell viability decrease is in relation to uptake by tumor cells.  相似文献   

17.
Abundant human interspersed repetitive DNA sequences of the form (dC-dA)n · (dG-dT)n have been shown to exhibit length polymorphisms. Examination of over 100 human (dC-dA)n · (dG-dT)n sequences revealed that the sequences differed from each other both in numbers of repeats and in repeat sequence type. Using a set of precise classification rules, the sequences were divided into three categories: perfect repeat sequences without interruptions in the runs of CA or GT dinucleotides (64% of total), imperfect repeat sequences with one or more interruptions in the run of repeats (25%), and compound repeat sequences with adjacent tandem simple repeats of a different sequence (11%). Informativeness of (dC-dA)n · (dG-dT)n markers in the perfect sequence category was found to increase with increasing average numbers of repeats. PIC values ranged from 0 at about 10 or fewer repeats to above 0.8 for sequences with about 24 or more repeats. (dC-dA)n · (dG-dT)n polymorphisms in the imperfect sequence category showed lower informativeness than expected on the basis of the total numbers of repeats. The longest run of uninterrupted CA or GT repeats was found to be the best predictor of informativeness of (dC-dA)n · (dG-dT)n polymorphisms regardless of the repeat sequence category.  相似文献   

18.
H. van Ormondt  B. Hesper 《Gene》1983,21(3):217-226
The nucleotide sequences of human adenovirus serotypes 12 (Ad 12, oncogenic subgroup A), 7 (Ad7, weakly oncogenic subgroup B) and 5 (Ad5, non-oncogenic subgroup C) DNAs have been compared. The region studied stretches from the termination codon of region Ela (m.p. 4.2) and comprises the entire region of the three viral DNAs. ending at the polyadenylation signal of the gene for viral polypeptide IVa2 (m.p. 11.2). The homology in the sequences encoding the Elb proteins of Mr 20000 and Mr 55000 is 55–60%, when two serotypes are compared, and about 45% in a three-strain comparison. However, a short internal segment encoding the C terminus of the Mr 20000 protein, and at the same time amino acids 23-120 of the Mr 55000 protein show a much higher degree of divergence in the three strains, as do the noncoding areas. The present study does not reveal how the three serotypes are phylogenetically related.  相似文献   

19.
Nitroimidazoles such as PA-824 and OPC-67683 are currently in clinical development as members of a promising new class of therapeutics for tuberculosis. While the antitubercular activity of these compounds is high, they both suffer from poor water solubility thus complicating development. We determined the single crystal X-ray structure of PA-824 and found a close packing of the nitroimidazoles facilitated by a pseudoaxial conformation of the p-trifluoromethoxybenzyl ether. To attempt to disrupt this tight packing by destabilizing the axial preference of this side chain, we prepared the two diastereomers of the 7-methyl-nitroimidazo-oxazine. Determination of the crystal structure of the 7-(S)-methyl derivative (5, cis) revealed that the benzylic side chain remained pseudoaxial while the 7-(R)-methyl derivative (6, trans) adopted the desired pseudoequatorial conformation. Both derivatives displayed similar activities against Mycobacterium tuberculosis, but neither showed improved aqueous solubility, suggesting that inherent lattice stability is not likely to be a major factor in limiting solubility. Conformational analysis revealed that all three compounds have similar energetically accessible conformations in solution. Additionally, these results suggest that the nitroreductase that initially recognizes PA-824 is somewhat insensitive to substitutions at the 7-position.  相似文献   

20.
Two gold(I) mononuclear complexes have been prepared by reacting gold(I) tetrahydrothiophene with N,N′-di(2,6-methyl)phenylformamidine. The neutral complex [N,N′-di(2,6-methyl)phenylformamidine)-gold(I) chloride (C17H20AuClN2) (1), crystallizes in the triclinic group while the cationic [N,N′-di(2,6-methyl)phenylformamidine](tetrahydrothiophene)-gold(I) (C21H28AuN2S) (2) crystallizes with a nitrate anion in the monoclinic group P2(1)/n. Both compounds are good starting materials for synthetic gold chemistry.  相似文献   

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