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191.
Redirection of anthocyanin synthesis in Osteospermum hybrida by a two-enzyme manipulation strategy 总被引:2,自引:0,他引:2
Seitz C Vitten M Steinbach P Hartl S Hirsche J Rathje W Treutter D Forkmann G 《Phytochemistry》2007,68(6):824-833
Modern biotechnology has developed powerful tools for genetic engineering and flower colours are an excellent object to study possibilities and limitations of engineering strategies. Osteospermum hybrida became a popular ornamental plant within the last 20 years. Many cultivars display rose to lilac flower colours mainly based on delphinidin-derived anthocyanins. The predominant synthesis of delphinidin derivatives is referred to a strong endogenous flavonoid 3',5'-hydroxylase (F3'5'H) activity. Furthermore, since dihydroflavonol 4-reductase (DFR) of Osteospermum does not convert dihydrokaempferol (DHK) to leucopelargonidin, synthesis of pelargonidin-based anthocyanins is naturally not realised. In order to redirect anthocyanin biosynthesis in Osteospermum towards pelargonidin derivatives, we introduced cDNAs coding for DFRs which efficiently convert DHK to LPg. But neither the expression of Gerbera hybrida DFR nor of Fragaria x ananassa DFR - the latter is characterised by an unusual high substrate preference for DHK - altered anthocyanin composition in flowers of transgenic plants. However, chemical inhibition of F3'5'H activity in ray florets of dfr transgenic plants resulted in the accumulation of pelargonidin derivatives. Accordingly, retransformation of a transgenic plant expressing Gerbera DFR with a construct for RNAi-mediated suppression of F3'5'H activity resulted in double transgenic plants accumulating predominantly pelargonidin derivatives in flowers. 相似文献
192.
Martin Lützelberger Claudia A. Bottner Wiebke Schwelnus Susanne Zock-Emmenthal Aleh Razanau Norbert F. K?ufer 《Nucleic acids research》2010,38(5):1610-1622
The spliceosomal protein Prp1 (Prp6/U5-102 K) is necessary for the integrity of pre-catalytic spliceosomal complexes. We have identified a novel regulatory function for Prp1. Expression of mutations in the N-terminus of Prp1 leads to the accumulation of pre-catalytic spliceosomal complexes containing the five snRNAs U1, U2, U5 and U4/U6 and pre-mRNAs. The mutations in the N-terminus, which prevent splicing to occur, include in vitro and in vivo identified phosphorylation sites of Prp4 kinase. These sites are highly conserved in the human ortholog U5-102 K. The results presented here demonstrate that structural integrity of the N-terminus is required to mediate a splicing event, but is not necessary for the assembly of spliceosomes. 相似文献
193.
Validation of 2D‐animated pictures as an investigative tool in the behavioural sciences: A case study with a West African cichlid fish,Pelvicachromis pulcher 下载免费PDF全文
Ulrike Scherer Jean‐Guy J. Godin Wiebke Schuett 《Ethology : formerly Zeitschrift fur Tierpsychologie》2017,123(8):560-570
Virtual stimuli represent an increasingly popular tool in the study of animal behaviour. Modern techniques have the potential to simplify and improve traditional experiments using live stimuli. However, the increasing availability of diverse techniques is associated with problems and limitations. Although many new methods have been developed, their validation remains largely untested. In the present study, we therefore performed two experiments to test whether 2‐D animations of predators and conspecifics elicit biologically appropriate behavioural responses in male rainbow kribs, Pelvicachromis pulcher. Individual responses towards a sympatric natural fish predator, Parachanna obscura, were tested using live predators and still colour photographs, animated using PowerPoint©. Compared to control trials (empty aquarium and white computer screen, respectively), individuals decreased their activity in response to both live and animated predators. We found no difference in activity between live and animation trials. Further, we tested individual aggression (frequency of aggressive behaviours) exhibited towards live and animated conspecifics. Individual aggressive behaviours shown towards live and animated conspecifics were positively correlated. Moreover, an individual's mean distance towards the opponent was a suitable proxy for individual aggression permitting the facilitation and standardisation of an individual's aggression through the use of a tracking software compared with the more laborious, traditional manual assessment. Our results show that simple, inexpensive animation techniques have the potential to provide an easy‐to‐apply and useful technological advance in animal behaviour research. 相似文献
194.
Generation and characterization of ecto-ADP-ribosyltransferase ART2.1/ART2.2-deficient mice 下载免费PDF全文
Ohlrogge W Haag F Löhler J Seman M Littman DR Killeen N Koch-Nolte F 《Molecular and cellular biology》2002,22(21):7535-7542
This is the first study reporting the inactivation of a member of the mouse gene family of toxin-related ecto-ADP-ribosyltransferases (ARTs). Transfer of the ADP-ribose moiety from NAD onto extracellular arginine residues on T-cell membrane proteins is mediated by glycosylphosphatidylinositol-linked cell surface ARTs. Exposure of T cells to ecto-NAD blocks T-cell activation and induces T-cell apoptosis. To determine a possible role of ecto-ART2.1 and ART2.2 in these processes, we generated ART2.1/ART2.2 double-knockout mice. ART2-deficient mice were healthy and fertile and showed normal development of lymphoid organs. ART2-deficient T cells showed a dramatically reduced capacity to ADP-ribosylate cell surface proteins, indicating that most if not all ART activity on the T-cell surface can be attributed to the ART2s. Moreover, ART2-deficient T cells were completely resistant to NAD-induced apoptosis and partially resistant to NAD-mediated suppression of proliferation. These results demonstrate that the ART2 ectoenzymes are an essential component in the regulation of T-cell functions by extracellular NAD, e.g., following release of NAD upon lysis of cells in tissue injury and inflammation. 相似文献
195.
Wiebke Handke Christina Luig Branka Popovi? Astrid Krmpoti? Stipan Jonji? Wolfram Brune 《Journal of virology》2013,87(6):3592-3596
Apoptosis induction is an important host defense mechanism to control viral infection, which is antagonized by viral proteins. Murine cytomegalovirus m41.1 encodes a viral inhibitor of BAK oligomerization (vIBO) that blocks the mitochondrial apoptosis mediator BAK. However, its importance for viral fitness in vivo has not been investigated. Here, we show that an m41.1-deficient virus attains reduced titers in salivary glands of wild-type but not Bak1−/− mice, indicating a requirement of BAK inhibition for optimal dissemination in vivo. 相似文献
196.
mer K. Coskun Aurle Vuillemin Florence Schubotz Frieder Klein Susanna E. Sichel Wolfgang Eisenreich William D. Orsi 《The ISME journal》2022,16(1):257
Thermodynamic models predict that H2 is energetically favorable for seafloor microbial life, but how H2 affects anabolic processes in seafloor-associated communities is poorly understood. Here, we used quantitative 13C DNA stable isotope probing (qSIP) to quantify the effect of H2 on carbon assimilation by microbial taxa synthesizing 13C-labeled DNA that are associated with partially serpentinized peridotite rocks from the equatorial Mid-Atlantic Ridge. The rock-hosted seafloor community was an order of magnitude more diverse compared to the seawater community directly above the rocks. With added H2, peridotite-associated taxa increased assimilation of 13C-bicarbonate and 13C-acetate into 16S rRNA genes of operational taxonomic units by 146% (±29%) and 55% (±34%), respectively, which correlated with enrichment of H2-oxidizing NiFe-hydrogenases encoded in peridotite-associated metagenomes. The effect of H2 on anabolism was phylogenetically organized, with taxa affiliated with Atribacteria, Nitrospira, and Thaumarchaeota exhibiting the most significant increases in 13C-substrate assimilation in the presence of H2. In SIP incubations with added H2, an order of magnitude higher number of peridotite rock-associated taxa assimilated 13C-bicarbonate, 13C-acetate, and 13C-formate compared to taxa that were not associated with peridotites. Collectively, these findings indicate that the unique geochemical nature of the peridotite-hosted ecosystem has selected for H2-metabolizing, rock-associated taxa that can increase anabolism under high H2 concentrations. Because ultramafic rocks are widespread in slow-, and ultraslow-spreading oceanic lithosphere, continental margins, and subduction zones where H2 is formed in copious amounts, the link between H2 and carbon assimilation demonstrated here may be widespread within these geological settings.Subject terms: Microbial ecology, Water microbiology, Microbial biooceanography, Microbiome, Biogeochemistry 相似文献
197.
198.
Luminita Stoenica Wiebke Wilkars Arne Battefeld Konstantin Stadler Roland Bender Ulf Strauss 《Developmental neurobiology》2013,73(10):785-797
The distribution of ion channels in neurons regulates neuronal activity and proper formation of neuronal networks during neuronal development. One of the channels is the hyperpolarization‐activated cyclic nucleotide‐gated (HCN) channel constituting the molecular substrate of hyperpolarization‐activated current (Ih). Our previous study implied a role for the fastest activating subunit HCN1 in the generation of Ih in rat neonatal cortical plate neurons. To better understand the impact of HCN1 in early neocortical development, we here performed biochemical analysis and whole‐cell recordings in neonatal cortical plate and juvenile layer 5 somatosensory neurons of HCN1?/? and control HCN1+/+ mice. Western Blot analysis revealed that HCN1 protein expression in neonatal cortical plate tissue of HCN+/+ mice amounted to only 3% of the HCN1 in young adult cortex and suggested that in HCN1?/? mice other isoforms (particularly HCN4) might be compensatory up‐regulated. At the first day after birth, functional ablation of the HCN1 subunit did not affect the proportion of Ih expressing pyramidal cortical plate neurons. Although the contribution of individual subunit proteins remains open, the lack of HCN1 markedly slowed the current activation and deactivation in individual Ih expressing neurons. However, it did not impair maximal amplitude/density, voltage dependence of activation, and cAMP sensitivity. In conclusion, our data imply that, although expression is relatively low, HCN1 contributes substantially to Ih properties in individual cortical plate neurons. These properties are significantly changed in HCN1?/?, either due to the lack of HCN1 itself or due to compensatory mechanisms. © 2013 Wiley Periodicals, Inc. Develop Neurobiol 73: 785–797, 2013 相似文献
199.
Schlörmann W John M Steiniger F Westermann M Richter W 《Histochemistry and cell biology》2007,127(6):633-639
The recently developed freeze-fracture replica immunolabeling technique uses sodium dodecyl sulfate to clean replicas obtained
from chemically unfixed, rapidly frozen cells by evaporation of platinum as first and carbon as second replication layer.
The detergent dissolves remains of cellular material with the exception of components which are in direct contact to the replica
film. Membrane lipids and membrane protein complexes of the protoplasmic and the exoplasmic membrane halves remain attached
to the replica film and are accessible for cytochemical localization. We immunolabeled the membrane proteins caveolin-1 and
connexin 43 in mouse cell lines as well as the membrane attached protein tetrachloroethene reductive dehalogenase (PceA) in
bacterial cells at freeze-fracture replicas generated by different evaporation parameters. The labeling experiments for caveolin-1
and the PceA showed that freeze-fracture replication of cellular membranes accomplished with thin platinum layers as well
as replication with carbon as first evaporation layer lead in these cases to an improved antigen retrieval, whereas the labeling
efficiency of connexin 43 was not affected by different evaporation conditions. 相似文献
200.