共查询到20条相似文献,搜索用时 31 毫秒
1.
R. Aquino I. Behar F. De Simone C. Pizza F. Senatore 《Biochemical Systematics and Ecology》1985,13(3):251-252
Six phenanthrene derivatives whose occurrence in T. communis is already reported and 5 and 6, previously described as the acetates after acetylation of the mixture of the two natural compounds, were isolated from the rhizomes of T. communis. 1H and 13C NMR spectral data are reported. 相似文献
2.
From the bark of Cryptocarya amygdalina two new olefinic acids with a tetracyclo(4.3.02.4.03.7) non-8-enemoiety are reported. From the same source the benzylisoquinoline alkaloids orientaline and laudanidine are also reported. 相似文献
3.
E. Pelizzetti E. Pramauro M.J. Blandamer J. Burgess N. Gosal 《Inorganica chimica acta》1985,102(2):163-167
Rate constants and activation parameters (ΔH≠ and ΔS≠)are reported for the oxidation of ferrocene by the tris-1,10-phenanthrolinecobalt(III) cation in t-butyl alcoholwater and in acetonewater solvent mixtures. Solvent effects on reactivity trends for these systems, for this same reaction in methanolwater mixtures, and for cobalt(II)-catalysed racemisation of Co(phen)33+ in t-butyl alcoholwater solvent mixtures are analysed into initial state and transition state contributions. The dependences of solubilities on solvent composition for ferrocene and for [Co(phen)3](ClO4)3 in methanol, t-butyl alcohol, and acetonewater mixtures are also reported; these results are needed in order to establish solvent effects on the initial states of the reactions studied. 相似文献
4.
Huda Abdel-Hamid Kimberley Chin Wolfgang Moeder Keiko Yoshioka 《Plant signaling & behavior》2011,6(11):1817-1819
Recently, we reported the role of Arabidopsis cyclic nucleotide-gated ion channel (AtCNGC) 11 and 12 in Ca2+-dependent physiological responses. AtCNGC11 and 12 have been reported to be involved in plant immunity, but whether these channels play additional physiological roles was not clear before. Using single and double knockout mutants, we have found that these channels play significant roles in Ca2+ signaling, which mediates several physiological processes, such as gravitropic bending and senescence. Here, we conducted a high throughput, non-biased chemical screen using the gain-of-function mutant of AtCNGC11 and 12, cpr22. Our data presented here indicates that Ca2+ but not K+ channel blockers suppress AtCNGC11/12-induced lethality. Our data further suggest that AtCNGC11 and 12 are involved in Ca2+-dependent, but not K+-dependent physiological responses in planta. 相似文献
5.
Absorption kinetics of [14C]glucose and [β-methyl-14C]glucoside in Hymenolepis diminuta are reported. β-Methylglucoside (βMG) is a pure competitive inhibitor of [14C]glucose transport and has kinetic parameters, Vmax and Kt, for transport similar to those reported for glucose. While absorbed 14C-βMG is not metabolized, transport of this glucose analog retains the general characteristics which have been established for glucose transport including: (1) Na+ dependence, (2) inhibition by K+, (3) sensitivity to phlorizin and various hexoses, (4) transport against an apparent concentration gradient, and (5) increase in worm water during accumulation. It is concluded that glucose and βMG are transported by the same system. The value of using βMG to study the mechanism of hexose transport and accumulation in H. diminuta is suggested. 相似文献
6.
Stephen J. Blunden Peter J. Smith Peter J. Beynon Duncan G. Gillies 《Carbohydrate research》1981,88(1):9-18
119Sn-N.m.r. spectra are reported for toluene solutions of the tributylstannyl ethers of 2,3,4,6-tetra-O-methyl-d)-glucose, 1,2:3,4-di-O-isopropylidene-α-d-galactopyranose, methyl 2,3-di-O-methyl-α-d-glucopyranoside, and methyl 4,6-O-benzylidene-α-d-glucopyranoside, and the dibutylstannyl ether of the last sugar. In the reaction of bis(tributyltin) oxide with methyl 4,6-O-benzylidene-α-d-glucopyranoside in toluene, HO-3 is much more reactive than HO-2. The presence of the various tin-containing species is readily apparent from the 119Sn-spectra. The importance of suppressing the nuclear Overhauser effect is demonstrated. The appearance of 119Sn satellites in the 13C-n.m.r. spectra demonstrates couplings of the types, 2J(119Sn-O-13C) and 3J(119Sn-O-C-13C), forthe first time, and, together with the 13C-chemical shifts, facilitates the determination of the site of substitution. The 119Sn-chemical shifts show that different states of coordination may be recognised. However, although different sites of substitution produce separate resonances, no simple relationship between shift and position is found. 13C-Chemical shifts are reported for methyl 4,6-O-benzylidene-α-d-glucopyranoside and its tributylstannyl ethers, and substituent effects are discussed. 相似文献
7.
Steffen Meyer 《Inorganica chimica acta》2010,363(12):3088-3092
Complexes of FeCl2 with the known bis(3-methyl-2-thione-imidazolyl)methane (L1) and the new bis(3-tert-butyl-2-thione-imidazolyl)methane (L2) are reported. For both [L1FeCl2]n (3) and [L2FeCl2]n (4) X-ray crystallography reveals that 1D-polymeric chain structures are present in the solid state, with the two mercaptoimidazolyl units of L1 and L2 coordinating to different metal ions. Complexes 3 and 4 are further characterized by Mössbauer spectroscopy and SQUID magnetometry. NMR spectroscopy suggests that the complexes largely dissociate in polar solvents. X-ray structures of L2 and its precursor bis(imidazolium) salt are also reported. 相似文献
8.
Single crystal X-ray diffraction and high-resolution 1H and 13C NMR spectral data for 4,6-di-O-acetyl-2,3-dideoxy-α-d-erythro-hex-2-enopyranosyl sulfamide, a selective inhibitor of carbonic anhydrase isozyme IX, are reported. The 0H5 was found to be the preferred form for this glycosyl sulfamide, both in the crystal lattice and in solution. 相似文献
9.
Antonio C. Herrera Braga Susana Zacchino Héctor Badano Manuel González Sierra Edmundo A. Rúveda 《Phytochemistry》1984,23(9):2025-2028
The 13C NMR spectra of the erythro and threo forms of representative members of the 8-O-4′ type of neolignans were recorded and the signals assigned. Based on these assignments and on the comparison with previously reported 1H NMR data, the most probable conformations for the above mentioned stereoisomers are suggested. 相似文献
10.
Longbao Zhu Wenjing Cui Yueqin Fang Yi Liu Xinxing Gao Zhemin Zhou 《Biotechnology letters》2013,35(5):751-756
The industrial-scale production of phenylalanine ammonia-lyase (PAL) mainly uses strains of Rhodotorula. However, the PAL gene from Rhodotorula has not been cloned. Here, the full-length gene of PAL from Rhodotorula glutinis was isolated. It was 2,121 bp, encoding a polypeptide with 706 amino acids and a calculated MW of 75.5 kDa. Though R. glutinis is an anamorph of Rhodosporium toruloides, the amino acid sequences of PALs them are not the same (about 74 % identity). PAL was expressed in E. coli and characterized. Its specific activity was 4.2 U mg?1 and the k cat/K m was 1.9 × 104 mM?1 s?1, exhibiting the highest catalytic ability among the reported PALs. The genetic and biochemical information reported here should facilitate future application in industry. 相似文献
11.
Yong Li Xianfu Wu Jianbei Li Yinghong Wang Shishan Yu Haining Lv Jing Qu Zeper Abliz Jing Liu Yuanyan Liu Dan Du 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2010,878(3-4):381-390
Cardiac glycosides are a class of naturally occurring compounds that are characterized by some interesting biological activities and are widely distributed in the plant kingdom and can also be found in some animals. There is an interest in the chemical characterization of these molecules due to their toxicity and their use in medicines. In the study reported here, a combination of electrospray ionization tandem mass spectrometry with high-performance liquid chromatography equipped with diode-array detector (HPLC-DAD/ESI-MSn), and hyphenation to both liquid chromatography and nuclear magnetic resonance spectroscopy (HPLC/NMR) were utilized for the on-line analyses of cardiac glycosides from Periploca forrestii. The fragmentation patterns and 1H NMR spectra of nine isolated cardiac glycosides were investigated; their fragmentation rules and 1H NMR spectral characteristics were summarized and applied to the structural identification of similar constituents in fractions from P. forrestii. As a result, a total of nine trace cardiac glycosides were tentatively determined by analyses of accurate molecular masses, representative fragment ions and characteristic 1H NMR signals provided by HPLC/high-resolution mass spectrometry (HRMS), HPLC-DAD/ESI-MSn and HPLC/1H NMR experiments, respectively. Of these, eight (2–9) are new compounds and one (1) is reported from P. forrestii for the first time. Results of the present study can benefit the rapid identification and targeted isolation of new cardiac glycosides from crude plant extracts. 相似文献
12.
Min Wang Karmen K. Yoder Mingzhang Gao Bruce H. Mock Xiao-Ming Xu Andrew J. Saykin Gary D. Hutchins Qi-Huang Zheng 《Bioorganic & medicinal chemistry letters》2009,19(19):5636-5639
Fully automated synthesis and initial PET evaluation of a TSPO radioligand, [11C]PBR28 (N-(2-[11C]methoxybenzyl)-N-(4-phenoxypyridin-3-yl)acetamide), are reported. These results facilitate the potential preclinical and clinical PET studies of [11C]PBR28 in animals and humans. 相似文献
13.
In the brain, Glud1-encoded glutamate dehydrogenase plays a major role in the recycling of the neurotransmitter glutamate. We recently reported a new model of brain-specific Glud1 null mice (Cns-Glud1 ?/?) lacking glutamate dehydrogenase in the central nervous system. Cns-Glud1 ?/? mice exhibit reduced astrocytic glutamate breakdown and redirection of glutamate pathways without altering synaptic transmission. Cns-Glud1 ?/? mice were generated using LoxP and Nestin-Cre technology. Nestin-Cre mice are widely used to investigate gene deletion in the central nervous system. However, the Nes-Cre transgene itself was reported to induce a phenotype related to body weight gain. Here, we review the potential side-effects of Nes-Cre and analysed Cns-Glud1 ?/? body weight gain. Overall, Nestin-Cre mice may exhibit transient and moderate growth retardation during the few weeks immediately following weaning. Pending appropriate controls and homogenization of the genetic background, Nestin-Cre technology is a valuable tool enabling disruption of genes of interest in the central nervous system. 相似文献
14.
《Carbohydrate research》1986,148(2):199-207
A complete, unambiguous assignment of all of the 13C-n.m.r.-spectral signals of agarose oligomers produced by enzymic hydrolysis has been achieved. The 1J13C-H coupling constants are reported, and the chemical shifts and coupling constants of both the agarose polymer and oligomers are compared. 相似文献
15.
Short interspersed elements (SINEs) are moderately repetitive DNA sequences in eukaryotic genomes. Although eukaryotic genomes contain numerous SINEs copy, it is very difficult and laborious to isolate and identify them by the reported methods. In this study, the inverse PCR was successfully applied to isolate SINEs from Opsariichthys bidens genome in Eastern Asian Cyprinid. A group of SINEs derived from tRNAAla molecular had been identified, which were named Opsar according to Opsariichthys. SINEs characteristics were exhibited in Opsar, which contained a tRNAAla-derived region at the 5′ end, a tRNA-unrelated region, and AT-rich region at the 3′ end. The tRNA-derived region of Opsar shared 76 % sequence similarity with tRNAAla gene. This result indicated that Opsar could derive from the inactive or pseudogene of tRNAAla. The reliability of method was tested by obtaining C-SINE, Ct-SINE, and M-SINEs from Ctenopharyngodon idellus, Megalobrama amblycephala, and Cyprinus carpio genomes. This method is simpler than the previously reported, which successfully omitted many steps, such as preparation of probes, construction of genomic libraries, and hybridization. 相似文献
16.
The primary production and below-ground biomass of angiosperms were measured in four almost monospecific vegetation stands situated on a salt marsh along the Oosterschelde estuary, The Netherlands. Maximum below-ground biomass values found for Spartina anglica, Elymus pycnanthus, Halimione portulacoides and Triglochin maritima, were very high relative to values reported from other European salt marshes: 12 586, 9 717, 17 737 and 16 121 g m-2 respectively. These relatively high values may be due to the fineness of the sieve used, compared to other studies. The actual values are likely to be even higher because the sample treatment has probably caused loss of fine root material. Below-ground production estimates, based on the difference between maximum and minimum biomass, yielded: 6 044 g m-2 yr-1 for Spartina, 4 421 g m-2 yr-1 for Elymus, 7 799 g m-2 yr-1 for Halimione and 3 475 g m-2 yr-1 for Triglochin. This high production is mainly concentrated in the deeper layers of the root environment (20–60 cm). Although these production figures are considerably higher than those generally reported for comparable species or vegetation types in Europe, statistical evidence suggests that, for the first three species, they are real values rather than figures caused by random fluctuations. 相似文献
17.
Aditya Singh Bhumika Vaidya Indu Khatri T. N. R. Srinivas Srikrishna Subramanian Suresh Korpole Anil Kumar Pinnaka 《PloS one》2014,9(1)
Grimontia indica strain AK16T sp. nov. is the type strain of G. indica sp. nov. a new species within the genus Grimontia. This strain, whose genome is described here, was isolated from seawater sample collected from southeast coast of Palk Bay, India. G. indica AK16T is a Gram-negative, facultative aerobic rod shaped bacterium. There are only two other strains in the genus Grimontia one of which, Grimontia hollisae CIP 101886T, is a reported human pathogen isolated from human stool sample while the other, ‘Grimontia marina IMCC5001T’, was isolated from a seawater sample. As compared to the pathogenic strain Grimontia hollisae CIP 101886T, the strain AK16T lacks some genes for pathogenesis like the accessory colonization factors AcfA and AcfD, which are required for the colonization of the bacterium in the host body. While it carries some pathogenesis genes like OmpU, which are related to pathogenesis of Vibrio strains. This suggests that the life cycle of AK16T may include some pathogenic interactions with marine animal(s), or it may be an opportunistic pathogen. Study of the Grimontia genus is important because of the severe pathogenic traits exhibited by a member of the genus with only three species reported in total. The study will provide some vital information which may be useful in future clinical studies on the genus. 相似文献
18.
《Bioorganic chemistry》1987,15(2):167-182
The kinetics of the Ni(II)-catalyzed ester hydrolysis of O-acetyl-2-pyridine-carboxaldoxime, O-acetyl-2-acetylpyridineketoxime, and O-acetyl-6-carboxy-2-pyridine-carboxaldoxime are measured and the values of various kcat parameters are calculated for reaction paths involving one metal ion (kcatW and kcatOH) and two metal ions kcatA and kcatB). Examination of the kinetic data reveals that the kcatW and kcatOH paths for the Ni(II)-catalyzed reactions involve the same mechanism as those for the previously reported Cu(II)-catalyzed reactions. For the kcatA and kcatB paths, the mechanism involving binuclear Ni(II) ions is preferred by analogy with the previously reported Zn(II)-catalyzed reactions. Comparison of kcatOH values for the Cu(II)- and Ni(II)-catalyzed hydrolysis of 1–3 indicates that markedly different steric effects are exerted by the substituents of 2 and 3 on the catalytic behavior of the two metal ions. This is explained in terms of differences in the fit of the metal ions in the metal complexes of 1–3. Present results demonstrate that slight changes in the geometry around the central metal atom can affect the catalytic outcome significantly. The implications of the present results on metal substitution in metalloenzymes are also discussed. 相似文献
19.
Transhydrogenase (E.C. 1.6.1.1) couples the redox reaction between NAD(H) and NADP(H) to the transport of protons across a membrane. The enzyme is composed of three components. The dI and dIII components, which house the binding site for NAD(H) and NADP(H), respectively, are peripheral to the membrane, and dII spans the membrane. We have estimated dissociation constants (Kd values) for NADPH (0.87 μM), NADP+ (16 μM), NADH (50 μM), and NAD+ (100-500 μM) for intact, detergent-dispersed transhydrogenase from Escherichia coli using micro-calorimetry. This is the first complete set of dissociation constants of the physiological nucleotides for any intact transhydrogenase. The Kd values for NAD+ and NADH are similar to those previously reported with isolated dI, but the Kd values for NADP+ and NADPH are much larger than those previously reported with isolated dIII. There is negative co-operativity between the binding sites of the intact, detergent-dispersed transhydrogenase when both nucleotides are reduced or both are oxidised. 相似文献
20.
《International journal of radiation applications and instrumentation. Part B, Nuclear medicine and biology》1992,19(4):481-489
The synthesis, radiochemical analysis and biological characteristics of some 1,8-diamine-3,6-dithiaoctane derivatives labelled with Tc-99m are reported. Analysis by HPLC shows that most of the 99mTc-chelates are multicomponent. Furthermore, almost all 99mTc-complexes isolated by HPLC are lipophilic and stable in vitro. The biodistributions of the most lipophilic of these complexes were evaluated in mice. The N-morpholinylethyl and N,N'′-bisalicylyl derivatives of 1,8-diamine-3,6-dithiaoctane yielded 99mTc-complexes which exhibit considerable uptake and retention in organs of interest, such as the heart and the brain. 相似文献