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31.
32.
Fibroblast growth factor-1 (FGF-1) has both extra- and intracellular functions. To identify intracellular binding partners for FGF-1, we isolated proteins from U2OS human osteosarcoma cells interacting specifically with FGF-1. One of the isolated proteins was identified as protein kinase CK2 (CK2). We here provide evidence that FGF-1 binds to both the catalytic alpha-subunit and to the regulatory beta-subunit of CK2. The interaction between FGF-1 and CK2 alpha and beta was characterized by surface plasmon resonance, giving K(D) values of 0.4 +/- 0.3 and 1.2 +/- 0.2 microM, respectively. By using a novel assay for intracellular protein interaction, FGF-1 and CK2 alpha are shown to interact in vivo. In vitro, FGF-1 and FGF-2 are phosphorylated by CK2, and the presence of FGF-1 or FGF-2 was found to enhance the autophosphorylation of CK2 beta. A correlation between the mitogenic potential of FGF-1 mutants and their ability to bind to CK2 alpha was observed. The possible involvement of CK2 in the FGF-induced stimulation of DNA synthesis is discussed. 相似文献
33.
Xylulokinase Overexpression in Two Strains of Saccharomyces cerevisiae Also Expressing Xylose Reductase and Xylitol Dehydrogenase and Its Effect on Fermentation of Xylose and Lignocellulosic Hydrolysate 总被引:2,自引:0,他引:2 下载免费PDF全文
Bjrn Johansson Camilla Christensson Timothy Hobley Brbel Hahn-Hgerdal 《Applied microbiology》2001,67(9):4249-4255
Fermentation of the pentose sugar xylose to ethanol in lignocellulosic biomass would make bioethanol production economically more competitive. Saccharomyces cerevisiae, an efficient ethanol producer, can utilize xylose only when expressing the heterologous genes XYL1 (xylose reductase) and XYL2 (xylitol dehydrogenase). Xylose reductase and xylitol dehydrogenase convert xylose to its isomer xylulose. The gene XKS1 encodes the xylulose-phosphorylating enzyme xylulokinase. In this study, we determined the effect of XKS1 overexpression on two different S. cerevisiae host strains, H158 and CEN.PK, also expressing XYL1 and XYL2. H158 has been previously used as a host strain for the construction of recombinant xylose-utilizing S. cerevisiae strains. CEN.PK is a new strain specifically developed to serve as a host strain for the development of metabolic engineering strategies. Fermentation was carried out in defined and complex media containing a hexose and pentose sugar mixture or a birch wood lignocellulosic hydrolysate. XKS1 overexpression increased the ethanol yield by a factor of 2 and reduced the xylitol yield by 70 to 100% and the final acetate concentrations by 50 to 100%. However, XKS1 overexpression reduced the total xylose consumption by half for CEN.PK and to as little as one-fifth for H158. Yeast extract and peptone partly restored sugar consumption in hydrolysate medium. CEN.PK consumed more xylose but produced more xylitol than H158 and thus gave lower ethanol yields on consumed xylose. The results demonstrate that strain background and modulation of XKS1 expression are important for generating an efficient xylose-fermenting recombinant strain of S. cerevisiae. 相似文献
34.
Metallic nanoparticles of gold functionalized with oligonucleotides conventionally use a terminal thiol modification and have been used in a wide range of applications. Although readily available, the oligonucleotide–nanoparticle conjugates prepared in this way suffer from a lack of stability when exposed to a variety of small molecules or elevated temperatures. If silver is used in place of gold then this lack of stability is even more pronounced. In this study we report the synthesis of highly stabilized oligonucleotide–nanoparticle conjugates using a simple oligonucleotide modification. A modified solid support was used to generate 3′-thioctic acid modified oligonucleotides by treatment with an N-hydroxysuccimidyl ester of thioctic acid. Unusually, both gold and silver nanoparticles have been investigated in this study and show that these disulphide-modified oligonucleotide probes offer significant improvements in nanoparticle stability when treated with dithiothreitol (DTT) compared with monothiol analogues. This is a significant advance in oligonucleotide–nanoparticle conjugate stability and for the first time allows silver nanoparticles to be prepared that are more stable than standard gold-thiol functionalized nanoparticles. This opens up the possibility of using silver nanoparticles functionalized with oligonucleotides as an alternative to gold. 相似文献
35.
The ESCRT-III subunit hVps24 is required for degradation but not silencing of the epidermal growth factor receptor 下载免费PDF全文
Bache KG Stuffers S Malerød L Slagsvold T Raiborg C Lechardeur D Wälchli S Lukacs GL Brech A Stenmark H 《Molecular biology of the cell》2006,17(6):2513-2523
The endosomal sorting complexes required for transport, ESCRT-I, -II, and -III, are thought to mediate the biogenesis of multivesicular endosomes (MVEs) and endosomal sorting of ubiquitinated membrane proteins. Here, we have compared the importance of the ESCRT-I subunit tumor susceptibility gene 101 (Tsg101) and the ESCRT-III subunit hVps24/CHMP3 for endosomal functions and receptor signaling. Like Tsg101, endogenous hVps24 localized mainly to late endosomes. Depletion of hVps24 by siRNA showed that this ESCRT subunit, like Tsg101, is important for degradation of the epidermal growth factor (EGF) receptor (EGFR) and for transport of the receptor from early endosomes to lysosomes. Surprisingly, however, whereas depletion of Tsg101 caused sustained EGF activation of the mitogen-activated protein kinase pathway, depletion of hVps24 had no such effect. Moreover, depletion of Tsg101 but not of hVps24 caused a major fraction of internalized EGF to accumulate in nonacidified endosomes. Electron microscopy of hVps24-depleted cells showed an accumulation of EGFRs in MVEs that were significantly smaller than those in control cells, probably because of an impaired fusion with lyso-bisphosphatidic acid-positive late endosomes/lysosomes. Together, our results reveal functional differences between ESCRT-I and ESCRT-III in degradative protein trafficking and indicate that degradation of the EGFR is not required for termination of its signaling. 相似文献
36.
Cecilie S. Svenningsen Tobias Guldberg Frslev Jesper Bladt Lene Bruhn Pedersen Jonas Colling Larsen Rasmus Ejrns Camilla Fljgaard Anders Johannes Hansen Jacob Heilmann-Clausen Robert R. Dunn Anders P. Tttrup 《Biology letters》2021,17(3)
Monitoring insects across space and time is challenging, due to their vast taxonomic and functional diversity. This study demonstrates how nets mounted on rooftops of cars (car nets) and DNA metabarcoding can be applied to sample flying insect richness and diversity across large spatial scales within a limited time period. During June 2018, 365 car net samples were collected by 151 volunteers during two daily time intervals on 218 routes in Denmark. Insect bulk samples were processed with a DNA metabarcoding protocol to estimate taxonomic composition, and the results were compared to known flying insect richness and occurrence data. Insect and hoverfly richness and diversity were assessed across biogeographic regions and dominant land cover types. We detected 15 out of 19 flying insect orders present in Denmark, with high proportions of especially Diptera compared to Danish estimates, and lower insect richness and diversity in urbanized areas. We detected 319 species not known for Denmark and 174 species assessed in the Danish Red List. Our results indicate that the methodology can assess the flying insect fauna at large spatial scales to a wide extent, but may be, like other methods, biased towards certain insect orders. 相似文献
37.
Sarah Thiroux Samuel Dupont Camilla L. Nesbø Nadège Bienvenu Mart Krupovic Stéphane L'Haridon Dominique Marie Patrick Forterre Anne Godfroy Claire Geslin 《Environmental microbiology》2021,23(7):3614-3626
Deep-sea hydrothermal vents are inhabited by complex communities of microbes and their viruses. Despite the importance of viruses in controlling the diversity, adaptation and evolution of their microbial hosts, to date, only eight bacterial and two archaeal viruses isolated from abyssal ecosystems have been described. Thus, our efforts focused on gaining new insights into viruses associated with deep-sea autotrophic archaea. Here, we provide the first evidence of an infection of hyperthermophilic methanogenic archaea by a head-tailed virus, Methanocaldococcus fervens tailed virus 1 (MFTV1). MFTV1 has an isometric head of 50 nm in diameter and a 150 nm-long non-contractile tail. Virions are released continuously without causing a sudden drop in host growth. MFTV1 infects Methanocaldococcus species and is the first hyperthermophilic head-tailed virus described thus far. The viral genome is a double-stranded linear DNA of 31 kb. Interestingly, our results suggest potential strategies adopted by the plasmid pMEFER01, carried by M. fervens, to spread horizontally in hyperthermophilic methanogens. The data presented here open a new window of understanding on how the abyssal mobilome interacts with hyperthermophilic marine archaea. 相似文献
38.
Direct fitness benefits explain mate preference,but not choice,for similarity in heterozygosity levels 下载免费PDF全文
Under sexual selection, mate preferences can evolve for traits advertising fitness benefits. Observed mating patterns (mate choice) are often assumed to represent preference, even though they result from the interaction between preference, sampling strategy and environmental factors. Correlating fitness with mate choice instead of preference will therefore lead to confounded conclusions about the role of preference in sexual selection. Here we show that direct fitness benefits underlie mate preferences for genetic characteristics in a unique experiment on wild great tits. In repeated mate preference tests, both sexes preferred mates that had similar heterozygosity levels to themselves, and not those with which they would optimise offspring heterozygosity. In a subsequent field experiment where we cross fostered offspring, foster parents with more similar heterozygosity levels had higher reproductive success, despite the absence of assortative mating patterns. These results support the idea that selection for preference persists despite constraints on mate choice. 相似文献
39.
Trehalose preserves DDA/TDB liposomes and their adjuvant effect during freeze-drying 总被引:4,自引:0,他引:4
Christensen D Foged C Rosenkrands I Nielsen HM Andersen P Agger EM 《Biochimica et biophysica acta》2007,1768(9):2120-2129
Disaccharides are well-known reagents to protect biostructures like proteins and phospholipid-based liposomes during freezing and drying. We have investigated the ability of the two disaccharides trehalose and sucrose to stabilize a novel, non-phospholipid-based liposomal adjuvant composed of the cationic dimethyldioctadecylammonium (DDA) and trehalose 6,6'-dibehenate (TDB) upon freeze-drying. The liposomes were freeze-dried using a human dose concentration containing 2.5 mg/ml DDA and 0.5 mg/ml TDB with varying concentrations of the two sugars. The influence on particle size upon rehydration was investigated using photon correlation spectroscopy (PCS) and the gel to fluid phase transition was examined by differential scanning calorimetry (DSC). Data revealed that concentrations above 211 mM trehalose protected and preserved DDA/TDB during freeze-drying, and the liposomes were readily rehydrated. Sucrose was less efficient as a stabilizer and had to be used in concentrations above 396 mM in order to obtain the same effect. Immunization of mice with the tuberculosis vaccine candidate Ag85B-ESAT-6 in combination with the trehalose stabilized adjuvant showed that freeze-dried DDA/TDB liposomes retained their ability to stimulate both a strong cell-mediated immune response and an antibody response. These findings show that trehalose at isotonic concentrations protects cationic DDA/TDB-liposomes during freeze-drying. Since this is not the case for liposomes based on DDA solely, we suggest that the protection is facilitated via direct interaction with the headgroup of TDB and a kosmotropic effect, whereas direct interaction with DDA plays a minor role. 相似文献
40.
Beylergil Sinem Balta Murray Jordan Noecker Angela M. Gupta Palak Kilbane Camilla McIntyre Cameron C. Shaikh Aasef G. Ghasia Fatema F. 《Journal of computational neuroscience》2021,49(3):345-356
Journal of Computational Neuroscience - Miniature yoked eye movements, fixational saccades, are critical to counteract visual fading. Fixational saccades are followed by a return saccades forming... 相似文献