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201.
Sebastian Jähne Fabian Mikulasch Helge G.H. Heuer Sven Truckenbrodt Paola Agüi-Gonzalez Katharina Grewe Angela Vogts Silvio O. Rizzoli Viola Priesemann 《Cell reports》2021,34(11):108841
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202.
203.
Structural comparison of I-A antigens produced by a cloned murine T suppressor cell line with B-Cell-Derived I-A 总被引:2,自引:0,他引:2
Norbert Kocht Bernd Arnold Günter J. Hämmerling Joachim Heuer Eckehart Kölsch 《Immunogenetics》1983,17(5):497-505
A cloned, antigen-specific T suppressor cell line derived from a CBA mouse expresses large amounts of I-A and I-E antigens. Comparative two-dimensional polyacrylamid gel electrophoresis of biosynthetically labeled I-A antigens immunoprecipitated with a variety of monoclonal I-Ak-specific antibodies suggested that alpha, beta and Ii polypeptide chains are identical with B-cell-derived I-A. Dimeric complexes formed by I-A chains derived from B or T suppressor cells were also similar with two major exceptions. Pulse-labeled T-cell-derived Ia antigen was complexed with two additional unknown components of about 31K. These components were not visible in pulse-chased (processed) materials. In addition, T suppressor-cell-derived I-A antigens did not contain S-S linked dimers consisting of processed alpha and beta chains, which are usually formed during solubilization of B cells. We consider the possibility that in T cells these chains are associated with other structures, thus preventing S-S linkage between alpha and beta chains. 相似文献
204.
An acyltransferase from cell cultures of Chenopodium rubrum was purified 515-fold with a 2.5 % recovery. This enzyme catalyzes the transfer of hydroxycinnamic acids from 1–0-hydroxycinnamoyl-/β-glucose to the C-2 hydroxy group of glucuronic acid of amaranthin (betanidin 5-O-glucuronosylglucose). The invivo products formed are celosianin I (4-coumaroylama-ranthin) and celosianin II (feruloylamaranthin). The enzyme can be classified as l-0-hydroxycinnamoyl-β-glucose: amaranthin O-hydroxycinnamoyl-transferase (EC 2.3.1.-). Its molecular weight was determined by gel filtration column chromatography to be ca. 69.5 kDa. Maximal rate of product formation was found to be at pH 5.6. The isoelectric point of the enzyme was at pH 4.7. The reaction temperature maximum was at 37 °C and the apparent energy of activation was calculated to be 44.5kJ mor?1. The enzyme showed a Vmax of 910pkat (mg protein)?1 with amaranthin as acceptor and feruloylglucose as acyl donor. The ratios of Vmax/Km values for sinapoyl-, feruloyl, caffeoyl- and 4-coumaroylglucoses were found to be 100:56:56:40. Donor competition experiments support the conclusion that one single enzyme is responsible for the ester formation with the different hydroxycinnamic acids. From the possible acceptors tested, only amaranthin (15S configuration) and isoamaranthin (15R) were esterified with Km values of 280 and 800 μM, respectively. Catalytic effectivity (Vmix/Km) was found at a relative ratio 15S:15R of 100:42. Betanin (betanidin 5-O-glucoside) and gomphrenin I (betanidin 6-O-glucoside) were not accepted. Some other acylated betacyanin-containing members of four families of the Caryophyllales were investigated and showed the same type of hydroxycinnamoyltransferase activity with 1-O-hydroxycinnamoylglucose as acyl donor, but with different acceptor molecule specificities. 相似文献
205.
Felix Beulig Verena B Heuer Denise M Akob Bernhard Viehweger Marcus Elvert Martina Herrmann Kai-Uwe Hinrichs Kirsten Küsel 《The ISME journal》2015,9(3):746-759
Effects of extremely high carbon dioxide (CO2) concentrations on soil microbial communities and associated processes are largely unknown. We studied a wetland area affected by spots of subcrustal CO2
degassing (mofettes) with focus on anaerobic autotrophic methanogenesis and acetogenesis because the pore gas phase was largely hypoxic. Compared with a reference soil, the mofette was more acidic (ΔpH ∼0.8), strongly enriched in organic carbon (up to 10 times), and exhibited lower prokaryotic diversity. It was dominated by methanogens and subdivision 1
Acidobacteria, which likely thrived under stable hypoxia and acidic pH. Anoxic incubations revealed enhanced formation of acetate and methane (CH4) from hydrogen (H2) and CO2
consistent with elevated CH4
and acetate levels in the mofette soil.
13CO2
mofette soil incubations showed high label incorporations with ∼512 ng
13C g (dry weight (dw)) soil−1 d−1
into the bulk soil and up to 10.7 ng
13C g (dw) soil−1 d−1
into almost all analyzed bacterial lipids. Incorporation of CO2-derived carbon into archaeal lipids was much lower and restricted to the first 10 cm of the soil. DNA-SIP analysis revealed that acidophilic methanogens affiliated with
Methanoregulaceae
and hitherto unknown acetogens appeared to be involved in the chemolithoautotrophic utilization of
13CO2. Subdivision 1
Acidobacteriaceae
assimilated
13CO2
likely via anaplerotic reactions because
Acidobacteriaceae
are not known to harbor enzymatic pathways for autotrophic CO2
assimilation. We conclude that CO2-induced geochemical changes promoted anaerobic and acidophilic organisms and altered carbon turnover in affected soils. 相似文献
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209.
Prevalence of streptomycin-resistance genes in bacterial populations in European habitats 总被引:2,自引:0,他引:2
210.
Mushroom bodies are prominent brain neuropils present in most arthropod representatives. Similar structures in the brain of
certain polychaete species are possibly homologous to these structures. Using three-dimensional reconstruction techniques,
we investigated the structural composition of the mushroom body neuropils in the polychaete species Nereis diversicolor and Harmothoe areolata. Comparative analysis revealed a common organization of neuropil substructures in both species that closely matches the basic
assembly of arthropod mushroom bodies. Concurring with earlier homology assessments, these neuroarchitectural similarities
provide support for a common origin of mushroom body neuropils in polychaetes and arthropods. Beyond that, differences in
the morphological differentiation of neuropil substructures indicate polychaete mushroom bodies to show a high degree of morphological
variability, thus impeding the quest for a common ground pattern of these brain centers. 相似文献