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201.
Resuspension cultures of Gibberella fujikuroi, strain GF-1a, were shown to metabolise potassium [3′-13C] mevalonate to 13C-enriched C19-gibberellins, plus 13CO2 (derived from the loss of carbon-20). The formation of [13C]-gibberellins could be observed in vivo using 13C NMR; however that of 13CO2 could not. In contrast, removal of the mycelium and concentration of the filtrate at pH 12 enabled the 13CO2 produced to be observed using 13C NMR. During incubations of H14CO2Na with this fungus, complete conversion to other radioactive products was observed, and the significance of these results in the light of previous work is discussed. 相似文献
202.
ZAKβ antagonizes and ameliorates the cardiac hypertrophic and apoptotic effects induced by ZAKα 下载免费PDF全文
Chien‐Yao Fu Wei‐Wen Kuo Tsung‐Jung Ho Su‐Ying Wen Ling‐Chun Lin Yan‐Shen Tseng Hui‐Chuan Hung Vijaya Padma Viswanadha Chih‐Yang Huang 《Cell biochemistry and function》2016,34(8):606-612
ZAK (sterile alpha motif and leucine zipper containing kinase AZK), a serine/threonine kinase with multiple biochemical functions, has been associated with various cell processes, including cell proliferation, cell differentiation, and cardiac hypertrophy. In our previous reports, we found that the activation of ZAKα signaling was critical for cardiac hypertrophy. In this study, we show that the expression of ZAKα activated apoptosis through both a FAS‐dependent pathway and a mitochondria‐dependent pathway by subsequently inducing caspase‐3. ZAKβ, an isoform of ZAKα, is dramatically expressed during cardiac hypertrophy and apoptosis. The interaction between ZAKα and ZAKβ was demonstrated here using immunoprecipitation. The results show that ZAKβ has the ability to diminish the expression level of ZAKα. These findings reveal an inherent regulatory role of ZAKβ to antagonize ZAKα and to subsequently downregulate the cardiac hypertrophy and apoptosis induced by ZAKα. 相似文献
203.
Mark S. Thomas 《Biometals》2007,20(3-4):431-452
The Burkholderia cepacia complex (Bcc) is comprised of at least 10 closely related species of Gram-negative proteobacteria that are associated with
infections in certain groups of immunocompromised individuals, particularly those with cystic fibrosis. Infections in humans
tend to occur in the lungs, which present an iron-restricted environment to a prospective pathogen, and accordingly members
of the Bcc appear to possess efficient mechanisms for iron capture. These bacteria specify up to four different types of siderophore
(ornibactin, pyochelin, cepabactin and cepaciachelin) that employ the full repertoire of iron-binding groups present in most
naturally occurring siderophores. Members of the Bcc are also capable of utilising some exogenous siderophores that they are
not able to synthesise. In addition to siderophore-mediated mechanisms of iron uptake, the Bcc possess mechanisms for acquiring
iron from haem and from ferritin. The Bcc therefore appear to be well-equipped for life in an iron-poor environment.
An erratum to this article can be found at 相似文献
204.
The hydroxylation at C-3′ of maclurin, an intermediate in mangiferin biosynthesis, has been studied. Labelled cinnamic acid, p-coumaric acid, caffeic acid, iriflophenone and maclurin were fed to Anemarrhena asphodeloides. Cinnamic acid and p-coumaric acid were better precursors than caffeic acid for mangiferin, and iriflophenone as well as maclurin was effectively incorporated into mangiferin and isomangiferin. These results show that maclurin is biosynthesized via hydroxylation of iriflophenone derived from p-coumarate in this plant. 相似文献
205.
206.
Heidrun Gerbling 《Plant biology (Stuttgart, Germany)》1993,106(5):380-387
Peroxisomes from mung bean hypocotyl (Vigna radiata L.) degrade 2-oxoisocaproate, the transamination product of leucine, via isobutyryl-CoA and propionyl-CoA to acetyl-CoA. The methyl group at the C-3 position forms a barrier to β-oxidation. This barrier is overcome in the peroxisomes by several enzymatic steps. Senecioate (3-methylcrotonate), 2-hydroxyisovalerate, and 2-oxoisovalerate were detected as free acid intermediates. Senecioate, formed from 3-methylcrotonyl-CoA, is transformed by enzymatic hydrolysis to 2-hydroxyisovalerate. 2-Hydroxyisovalerate is then oxidized to 2-oxoisovalerate in an H2O2-producing reaction, exhibiting 1:1 stoichiometry of the products, by a 2-hydroxyacid oxidase which is different from the peroxisomal marker enzyme glycollate oxidase. 2-oxoisovalerate is activated by an NAD-dependent oxidative decarboxylation to isobutyryl-CoA. Accumulation of 2-oxoisovalerate in the presence of arsenite, an inhibitor of oxidative decarboxylations, is a feature of this latter pathway of degradation of isovaleryl-CoA or senecioate. It is concluded that the barrier caused by the methyl group of 2-oxoisocaproate is surmounted in higher plant peroxisomes in a manner different to that in mammalian mitochondria. 相似文献
207.
《Bioorganic & medicinal chemistry》2014,22(21):5924-5934
With the continuing interest in deciphering the interplay between protein function and conformational changes, small fluorescence probes will be especially useful for tracking changes in the crowded protein interior space. Presently, we describe the potential utility of six unnatural amino acid fluorescence donors structurally related to tryptophan and show how they can be efficiently incorporated into a protein as fluorescence probes. We also examine the various photophysical properties of the new Trp analogues, which are significantly redshifted in their fluorescence spectra relative to tryptophan. In general, the Trp analogues were well tolerated when inserted into Escherichia coli DHFR, and did not perturb enzyme activity, although substitution for Trp22 did result in a diminution in DHFR activity. Further, it was demonstrated that D and E at position 37 formed efficient FRET pairs with acridon-2-ylalanine (Acd) at position 17. The same was also true for a DHFR construct containing E at position 79 and Acd at position 17. Together, these findings demonstrate that these tryptophan analogues can be introduced into DHFR with minimal disruption of function, and that they can be employed for the selective study of targeted conformational changes in proteins, even in the presence of unmodified tryptophans. 相似文献
208.
Wayne Rickoll David Rehkopf Catherine Dunn Amy Malmberg Karen VanWinkle-Swift 《Journal of phycology》1998,34(1):147-151
Iodine staining of clones of nitrogen-starved Chlamydomonas cells was used to screen for mutants with altered levels or altered composition of storage starch. Mutations leading to defects in quantity or morphology of starch granules not only can provide information on storage starch biosynthesis and granule assembly but can also be used as morphological markers in genetic and cell biological studies. A mutant of Chlamydomonas monoica Strehlow devoid of starch granules was obtained following ultraviolet mutagenesis. Nitrogen-starved cells of the sta-1 strain lacked pyrenoidal starch granules and granules normally associated with thylakoid membranes. The mutant phenotype was the consequence of a single Mendelian mutation that appeared to affect granule assembly rather than starch biosynthesis per se and that had no effect on vegetative growth, sexual reproduction, or zygospore viability. 相似文献
209.
210.
Christian P Craddock Nicolette Adams Fiona M Bryant Smita Kurup Peter J Eastmond 《Plant signaling & behavior》2015,10(10)
Coordination of membrane lipid biosynthesis is important for cell function during plant growth and development. Here we summarize our recent work on PHOSPHATIDIC ACID PHOSPHOHYDROLASE (PAH) which suggests that this enzyme is a key regulator of phosphaticylcholine (PC) biosynthesis in Arabidopsis thaliana. Disruption of PAH activity elevates phosphatidic acid (PA) levels and stimulates PC biosynthesis and biogenesis of the endoplasmic reticulum (ER). Furthermore, the activity of PHOSPHOCHOLINE CYTIDYLYLTRANSFERASE (CCT), which is the key enzyme controlling the rate of PC biosynthesis, is directly stimulated by PA and expression of a constitutively active version of CCT replicates the effects of PAH disruption. Hence PAH activity can control the abundance of PA, which in turn can modulate CCT activity to govern the rate of PC biosynthesis. Crucially it is not yet clear how PAH activity is regulated in Arabidopsis but there is evidence that PAH1 and PAH2 are both phosphorylated and further work will be required to investigate whether this is functionally significant. 相似文献