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91.
Different approaches to improve the enantioselectivity of biocatalytic systems are presented. These methodologies have been successfully applied to the preparation of optically active dihydropyridine, calcium antagonists, and cis-3-hydroxy-6-acetoxy-cyclohex-1-ene, a valuable chiral building block for natural products synthesis. The phenomenon of enantioselective inhibition is described and several new heterocyclic amines have been shown to be effective enantioselective inhibitors in the Candida lipase system. 相似文献
92.
The electron-microscopic technique for immunogold labelling of thawed cryosectioned material (K.T. Tokuyasu, 1989, Histochem J 21: 163–171) has been adapted for use with isolated chloroplasts. Percoll-purified pea (Pisum Sativum L. cv Feltham First) chloroplasts were fixed in a buffered glutaraldehyde solution and then infiltrated with a buffered solution of 10% polyvinylpyrrolidone in 2.07 M sucrose prior to freezing in liquid nitrogen and sectioning in an ultracryomicrotome. Sections were thawed, immunolabelled, and stained with ammonium molybdate in methyl cellulose on Formvar/carbon-coated Cu or Cu/Pd electron-microscope grids. Cryosectioning gave excellent structural preservation and retained antigenicity. The effectiveness of this technique in localizing proteins to their specific chloroplast compartment was assayed using antibodies raised against: (i) the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), a stromal protein, (ii) the chloroplast ATP synthase (CF1), a peripheral thylakoid protein, and (iii) different envelope membrane proteins. Antibodies raised against three members of the chloroplasticouterenvelopeprotein (OEP) import machinery, a 34-kDa protein (OEP34 or IAP34), the channel-forming 75-kDa protein (OEP75 or IAP75), and the 86-kDa precursor protein receptor (OEP86 or IAP86) were tested for their localization. The previous localization of OEP86, OEP75 and OEP34 to the outer envelope by biochemical methods was confirmed by our immuno electronmicroscopic analysis. Additionally, a constituent of the chloroplastic inner envelope protein (IEP) import machinery IEP 110 (IAP 100) was clearly localized to this membrane. Therefore, cryosectioning and immunogold labelling of intact chloroplasts provides a method for studying the localization of chloroplast proteins, especially those residing in the inner and outer envelope membranes.Abbreviations FCS
fetal calf serum
- IAP
import intermediate associated protein
- IEP
inner envelope protein
- OEP
outer envelope protein (numbers signifying the relative molecular mass in kilodaltons)
- PBS
phosphate buffered saline
- PVP
polyvinyl pyrrolidone
- Rubisco
ribulose-1,5-biophosphate carboxylase/oxygenase 相似文献
93.
Mcp3 is a novel mitochondrial outer membrane protein that follows a unique IMP‐dependent biogenesis pathway 下载免费PDF全文
94.
Stem cell therapy is a promising treatment for neurogenerative disease as well as inflammatory and immune mediated diseases.Decades of preclinical research has ... 相似文献
95.
Xenia Junge Katja A. Jacot Andreas Bosshard Petra Lindemann-Matthies 《Journal for Nature Conservation》2009,17(3):150-159
Arable land in Switzerland harbours low biodiversity and lacks permanent species-rich structures. To remedy this situation, improved field margins (IFMs) will be introduced as a new ecological compensation type in the Swiss Lowlands. IFMs are extensively managed, sown species- and flower-rich vegetation strips which provide both habitats for a wide range of species and valuable structures for the ecological network. However, the success of ecological compensation measures depends strongly on their acceptance by farmers and the general public. In summer 2004, we investigated in a case study the attitudes of 108 Swiss people to IFMs directly in the field. Study participants were asked to rate the attractiveness of IFMs of different species richness and composition that were presented to them, to explain their rating and to estimate the number of species present. In addition, they were asked to imagine a field margin of their particular liking, to describe it, and to state their opinion on several aspects of IFMs. Study participants responded very positively to species-rich vegetation. The more species-rich an IFM was perceived to be, the more it appealed to them. Species richness and general diversity were named as the main reasons for a positive rating. Study participants strongly approved the establishment of improved field margins. The positive rating and high acceptance of IFMs in this study indicate that they may be a successful new tool for biodiversity enhancement in intensively used agricultural landscapes. 相似文献
96.
We obtained a full-length cDNA encoding a carboxylesterase in Sesamia nonagrioides. The complete cDNA sequence is comprised of 1838 bp with an open reading frame encoding 576 amino acid residues with predicted molecular mass of 64.24 kDa. The deduced amino acid sequence showed high identity to JHE-Related of Trichoplusia ni (65% amino acid identity) and 49-46% amino acid identity to JHEs of other lepidopterans and contained all five functional motifs of insect JHEs. The gene has been termed as SnJHE-Related (SnJHER) to denote its similarity to other insect JHE genes and the occurrence of an unusual cysteine residue immediately adjacent to the catalytic serine, instead of the conventional alanine residue. Phylogenetic analyses localised SnJHER together with TnJHER in a branch of the lepidopteran's JHEs group, with other carboxylesterases (COEs) occuring in separated groups. The JH analog methoprene did not affect the expression of SnJHER in contrast to other insect JHEs. Additionally, ecdysteroid analogs induced SnJHER gene expression. The SnJHER mRNA levels were higher in long-day non-diapausing larvae than in short-day diapausing ones. In the fifth instar of non-diapausing and ninth instar of diapausing larvae, the SnJHER mRNAs reached higher expression levels on the days close to each larval molt. In the last (sixth) non-diapausing larval instar, SnJHER mRNA levels peaked in the intermolt period but were lower than during the fifth instar. 相似文献
97.
Krzysztof L. Hyrc Akwasi Minta P. Rogelio Escamilla Patrick P.L. Chan Xenia A. Meshik Mark P. Goldberg 《Cell calcium》2013
Although many synthetic calcium indicators are available, a search for compounds with improved characteristics continues. Here, we describe the synthesis and properties of Asante Calcium Red-1 (ACR-1) and its low affinity derivative (ACR-1-LA) created by linking BAPTA to seminaphthofluorescein. The indicators combine a visible light (450–540 nm) excitation with deep-red fluorescence (640 nm). Upon Ca2+ binding, the indicators raise their fluorescence with longer excitation wavelengths producing higher responses. Although the changes occur without any spectral shifts, it is possible to ratio Ca2+-dependent (640 nm) and quasi-independent (530 nm) emission when using visible (<490 nm) or multiphoton (∼780 nm) excitation. Therefore, both probes can be used as single wavelength or, less dynamic, ratiometric indicators. Long indicator emission might allow easy [Ca2+]i measurement in GFP expressing cells. The indicators bind Ca2+ with either high (Kd = 0.49 ± 0.07 μM; ACR-1) or low affinity (Kd = 6.65 ± 0.13 μM; ACR-1-LA). Chelating Zn2+ (Kd = 0.38 ± 0.02 nM) or Mg2+ (Kd ∼ 5 mM) slightly raises and binding Co2+ quenches dye fluorescence. New indicators are somewhat pH-sensitive (pKa = 6.31 ± 0.07), but fairly resistant to bleaching. The probes are rather dim, which combined with low AM ester loading efficiency, might complicate in situ imaging. Despite potential drawbacks, ACR-1 and ACR-1-LA are promising new calcium indicators. 相似文献
98.
A new dinoflagellate species, Blastodinium galatheanum sp. nov., was found parasitizing the planktonic copepods Acartia negligens and Acartia sp. in the Atlantic Ocean between the Azores and the Cape Verde Islands. These copepods have not previously been reported hosting a Blastodinium species. Characters that distinguish the new species are the shape and size of the trophic stage, its host species, and its predominantly solitary existence. Dinospores of Blastodinium galatheanum sp. nov. are peridinioid in nature and morphologically indistinguishable from dinospores of two other previously investigated Blastodinium species. SSU rRNA gene sequences from two isolates of this new species were almost identical and showed similarities to SSU rRNA sequences of other species of Blastodinium. A phylogenetic analysis based on SSU rRNA gene sequences suggested monophyly for all existing sequences of Blastodinium spp., including a sequence from the type species B. pruvoti, presented here for the first time. 相似文献
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100.