排序方式: 共有69条查询结果,搜索用时 16 毫秒
11.
Recombinant production of therapeutically active proteins has become a central focus of contemporary life science research. These proteins are often produced in mammalian cells, in order to obtain products with post-translational modifications similar to their natural counterparts. However, in cases where a fast and flexible system for recombinant production of proteins is needed, the use of mammalian cells is limited. The baculoviral insect cell system has proven to be a powerful alternative for the expression of a wide range of recombinant proteins in short time frames. The major drawback of baculoviral systems lies in the inability to perform mammalian-like glycosylation required for the production of therapeutic glycoproteins. In this study we integrated sequences encoding Caenorhabditis elegans N-acetylglucosaminyltransferase II and bovine β1,4-galactosyltransferase I into the backbone of a baculovirus genome. The thereby generated SweetBac virus was subsequently used for the production of the human HIV anti-gp41 antibody 3D6 by integrating heavy and light chain open reading frames into the SweetBac genome. The parallel expression of target genes and glycosyltransferases reduced the yield of secreted antibody. However, the overall expression rate, especially in the recently established Tnao38 cell line, was comparable to that of transient expression in mammalian cells. In order to evaluate the ability of SweetBac to generate mammalian-like N-glycan structures on 3D6 antibody, we performed SDS-PAGE and tested for the presence of terminal galactose using Riccinus communis agglutinin I. The mammalianised variants of 3D6 showed highly specific binding to the lectin, indicating proper functionality. To confirm these results, PNGase A released N-glycans were analyzed by MALDI-TOF-MS and shown to contain structures with mainly one or two terminal galactose residues. Since the presence of specific N-glycans has an impact on antibodies ability to exert different effector functions, we tested the binding to human Fc gamma receptor I present on U937 cells. 相似文献
12.
Majerović M Augustin G Jelincić Z Buković D Kekez T Matosević P Smud D Kinda E Golem AZ 《Collegium antropologicum》2008,32(3):703-707
Radiofrequency ablation (RFA) is one treatment modality for unresectable liver metastases. Patients with hepatic malignancies (n = 24) underwent elective RFA. All tumors were ablated with a curative intent, with a margin of 1 cm, in a single session of RFA. The median diameter of tumor was 3.1 cm (range 1.7-6.9 cm). Studied patients were not candidates for resection due to multifocal hepatic disease, extrahepatic disease, proximity to major vascular structures or presence of cirrhosis with functional hepatic reserve inadequate to tolerate major hepatic resection. Complete tumor necrosis was achieved in 87.5% and tumor recurred in 3 patients (12.5%) with lesions larger than 5 cm. Distant intrahepatic recurrence was diagnosed in another 4 (16.7%). Distant metastases were found in 7 (29.2%) patients. Four of these 7 patients had also distant intrahepatic recurrence of disease. Two and 5-years survival rates were 41.7% (10 patients) and 8.3% (2 patients) respectively. RFA is safe and effective option for patients with unresectable hepatic malignancies smaller than 5 cm without distant metastatic disease. RF ablation resulted in complete tumor necrosis in 87.5% with 2 and 5-years survival rates much higher than with chemotherapy alone or only supportive therapy, when survival is measured in weeks or months. If RFA is unavailable, percutaneous ethanol injection therapy can be done but with inferior survival rates. 相似文献
13.
Joao H. F. Pedra Sukanya Narasimhan Dubravko Rendić Kathleen DePonte Lesley Bell‐Sakyi Iain B. H. Wilson Erol Fikrig 《Cellular microbiology》2010,12(9):1222-1234
Fucosylated structures participate in a wide range of pathological processes in eukaryotes and prokaryotes. The impact of fucose on microbial pathogenesis, however, has been less appreciated in arthropods of medical relevance. Thus, we used the tick‐borne bacterium Anaplasma phagocytophilum– the agent of human granulocytic anaplasmosis to understand these processes. Here we show that A. phagocytophilum uses α1,3‐fucose to colonize ticks. We demonstrate that A. phagocytophilum modulates the expression of α1,3‐fucosyltransferases and gene silencing significantly reduces colonization of tick cells. Acquisition but not transmission of A. phagocytophilum was affected when α1,3‐fucosyltransferases were silenced during tick feeding. Our results uncover a novel mechanism of pathogen colonization in arthropods. Decoding mechanisms of pathogen invasion in ticks might expedite the development of new strategies to interfere with the life cycle of A. phagocytophilum. 相似文献
14.
Prof. Dr. Josip Tišljar M.Sc. Igor Vlahović Dr. Ivo Velić Dr. Dubravko Matičec Dr. Julie Robson 《Facies》1998,38(1):137-151
Summary During the Late Albian, Early and Middle Cenomanian in the NW part of the Adriatic Carbonate Platform (presentday Istria)
specific depositional systems characterised by frequent lateral and vertical facies variations were established within a formerly
homogeneous area, ranging from peritidal and barrier bars to the offshore-transition zone. In southern Istria this period
is represented by the following succession: thin-bedded peritidal peloidal and stromatolitic limestones (Upper Albian); well-bedded
foreshore to shoreface packstones/grainstones with synsedimentary dliding and slumping (Vraconian-lowermost Cenomanian); shoreface
to off-shore storm-generated limestones (Lower Cenomanian); massive off-shore to shoreface carbonate sand bodies (Lower Cenomanian);
prograding rudist bioclastic subaqueous dunes (Lower to Middle Cenomanian); rudist biostromes (Lower to Middle Cenomanian),
and high-energy rudist and ostreid coquina beds within skeletal wackestones/packstones (Middle Cenomanian).
Rapid changes of depositional systems near the Albian/Cenomanian transition in Istria are mainly the result of synsedimentary
tectonics and the establishment of extensive rudist colonies producing enormous quantities of bioclastic material rather than
the influence of eustatic changes. Tectonism is evidenced by the occurrence of sliding scars, slumps, small-scale synsedimentary
faults and conspicuous bathymetric changes in formerly corresponding environments. Consequently, during the Early Cenomanian
in the region of southern Istria, a deepening of the sedimentary environments occurred towards the SE, resulting in the establishment
of a carbonate ramp system. Deeper parts of the ramp were below fair-weather wave base (FWWB), while the shallower parts were
characterised by high-energy environments with extensive rudist colonies, and high organic production leading to the progradation
of bioclastic subaqueous dunes. This resulted in numerous shallowing- and coarsening-upwards clinostratified sequences completely
infilling formerly deeper environments, and the final re-establishment of the shallow-water environments over the entire area
during the Middle Cenomanian. 相似文献
15.
A potential connection between physico-chemical properties of mRNAs and cognate proteins, with implications concerning both the origin of the genetic code and mRNA–protein interactions, is unexplored. We compare pyrimidine content of naturally occurring mRNA coding sequences with the propensity of cognate protein sequences to interact with pyrimidines. The latter is captured by polar requirement, a measure of solubility of amino acids in aqueous solutions of pyridines, heterocycles closely related to pyrimidines. We find that the higher the pyrimidine content of an mRNA, the stronger the average propensity of its cognate protein’s amino acids to interact with pyridines. Moreover, window-averaged pyrimidine profiles of individual mRNAs strongly mirror polar-requirement profiles of cognate protein sequences. For example, 4953 human proteins exhibit a correlation between the two with |R| > 0.8. In other words, pyrimidine-rich mRNA regions quantitatively correspond to regions in cognate proteins containing residues soluble in pyrimidine mimetics and vice versa. Finally, by studying randomized genetic code variants we show that the universal genetic code is highly optimized to preserve these correlations. Overall, our findings redefine the stereo-chemical hypothesis concerning code’s origin and provide evidence of direct complementary interactions between mRNAs and cognate proteins before development of ribosomal decoding, but also presently, especially if both are unstructured. 相似文献
16.
17.
Geisler C Kotu V Sharrow M Rendic D Pöltl G Tiemeyer M Wilson IB Jarvis DL 《The Journal of biological chemistry》2012,287(35):29599-29609
Studying genetic disorders in model organisms can provide insights into heritable human diseases. The Drosophila neurally altered carbohydrate (nac) mutant is deficient for neural expression of the HRP epitope, which consists of N-glycans with core α1,3-linked fucose residues. Here, we show that a conserved serine residue in the Golgi GDP-fucose transporter (GFR) is substituted by leucine in nac(1) flies, which abolishes GDP-fucose transport in vivo and in vitro. This loss of function is due to a biochemical defect, not to destabilization or mistargeting of the mutant GFR protein. Mass spectrometry and HPLC analysis showed that nac(1) mutants lack not only core α1,3-linked, but also core α1,6-linked fucose residues on their N-glycans. Thus, the nac(1) Gfr mutation produces a previously unrecognized general defect in N-glycan core fucosylation. Transgenic expression of a wild-type Gfr gene restored the HRP epitope in neural tissues, directly demonstrating that the Gfr mutation is solely responsible for the neural HRP epitope deficiency in the nac(1) mutant. These results validate the Drosophila nac(1) mutant as a model for the human congenital disorder of glycosylation, CDG-IIc (also known as LAD-II), which is also the result of a GFR deficiency. 相似文献
18.
A 54 year old man sustained a third degree open fracture at the distal part of the right humerus with massive soft tissue defect involving most of the upper arm. The radial and median nerves were completely bared and exposed by 6 cm for radial and 3 cm for median nerve. The nerves were in continuity, but there was complete rupture of surrounding muscles: biceps, triceps and brachialis. The fracture was stabilized by external fixation method--reinforced by wires. Preoperative and postoperative sensorimotor status of the right hand was good. One year later sensory and motoric status of right hand showed no deficiencies, but flexion and extension in elbow were limited to 100 and 180 degrees respectively. Pronosupination was restricted. This case report is consistent with results of biomechanical studies in vitro confirming high tolerance of radial and median nerve to stretching injury. 相似文献
19.
Rendic D Linder A Paschinger K Borth N Wilson IB Fabini G 《The Journal of biological chemistry》2006,281(6):3343-3353
Neural pathways in invertebrates are often tracked using anti-horseradish peroxidase, a cross-reaction due to the presence of core alpha1,3-fucosylated N-glycans. In order to investigate the molecular basis of this epitope in a cellular context, we compared two Drosophila melanogaster cell lines: the S2 and the neuronal-like BG2-c6 cell lines. As shown by mass spectrometric and chromatographic analyses, only the BG2-c6 cell line expresses alpha1,3/alpha1,6-difucosylated N-glycans, a result that correlates with anti-horseradish peroxidase binding. Of all four alpha1,3-fucosyltransferase homologues previously identified, the core alpha1,3-fucosyltransferase (FucTA; EC 2.4.1.214) is expressed in the neuronal cell line as well as throughout fly development and in heads and bodies of flies of both sexes. This pattern is distinctive in comparison with the expression of the other three alpha1,3-fucosyltransferase homologues (FucTB, FucTC, and FucTD). Furthermore, only transfection of FucTA cDNA into S2 cells resulted in expression of the anti-horseradish peroxidase epitope, a result compatible with its substrate specificity in vitro. Finally, silencing of FucTA by RNAi in the neuronal cell line led to a significant reduction of anti-horseradish peroxidase binding. The present study, in conjunction with our previous in vitro data, thereby shows that FucTA is indispensable for expression of the neural carbohydrate epitope in Drosophila cells. 相似文献
20.
Biljana Balen Mirta Tkalec Dubravko Pavoković Branka Pevalek-Kozlina Marijana Krsnik-Rasol 《Journal of Plant Growth Regulation》2009,28(1):36-45
In vitro propagated plants of Mammillaria
gracilis Pfeiff. (Cactaceae) develop calli without any exogenous growth regulators. This habituated tissue spontaneously regenerates morphologically
normal as well as hyperhydric shoots. In this study, a possible involvement of activated oxygen metabolism in habituation
and hyperhydricity in in vitro propagated plants of Mammillaria
gracilis Pfeiff. (Cactaceae) was investigated. Significantly higher malondialdehyde (MDA) and carbonyl contents as well as hydrogen peroxide (H2O2) production were observed in habituated callus (HC), hyperhydric regenerated shoots (HS), and tumors (TT) in comparison to
normal regenerated shoots (NS). Lipoxygenase (LOX) activity showed a similar trend, with a clear increase in activity in HC
and HS. The activities of antioxidative enzymes, namely, peroxidase (POX), ascorbate peroxidase (APX), and catalase (CAT),
were also higher in HC, HS, and TT, whereas an increase in superoxide dismutase (SOD) activity was observed in HC and HS.
The majority of antioxidative isoenzymes were common to all cactus tissues, although a few tissue-specific bands were noticed.
Significant decreases in phenylalanine ammonia lyase (PAL) activity, total phenolic content, and lignification were found
in HS, HC, and TT in comparison to NS. Our results showed the appearance of a prominent oxidative stress in HC, HS, and TT
as well as a strong induction of the antioxidant system indicating that activated oxygen metabolism could be involved in habituation
and hyperhydricity and linked to the loss of tissue organization in M. gracilis.
B. Balen and M. Tkalec contributed equally to this work. 相似文献