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1.
Site-specific conjugation of small molecules to antibody molecules is a promising strategy for generation of antibody-drug conjugates. In this report, we describe the successful synthesis of a novel bifunctional molecule, 6-(azidomethyl)-2-pyridinecarboxyaldehyde (6-AM-2-PCA), which was used for conjugation of small molecules to peptides and antibodies. We demonstrated that 6-AM-2-PCA selectively reacted with N-terminal amino groups of peptides and antibodies. In addition, the azide group of 6-AM-2-PCA enabled copper-free click chemistry coupling with dibenzocyclooctyne-containing reagents. Bifunctional 6-AM-2-PCA mediated site-specific conjugation without requiring genetic engineering of peptides or antibodies. A key advantage of 6-AM-2-PCA as a conjugation reagent is its ability to modify proteins in a single step under physiological conditions that are sufficiently moderate to retain protein function. Therefore, this new click chemistry-based method could be a useful complement to other conjugation methods. 相似文献
2.
In the past years, in our laboratory, several cell lines have been generated starting from a human liver (H7). Some of them have been used successfully in studies of the infection with and propagation of Hepatitis B and Hepatitis C viruses. Recently, several lines of evidence indicated that the origin of these cell lines was uncertain. Therefore, we now have determined the genetic characteristics of these cell lines in comparison to HepG2 cells received from ATCC and to HepG2 isolates grown at other laboratories. Quadruplex fluorescent short tandem repeat (STR) typing and karyotyping were performed. In addition, some biochemical characteristics of selected clones were studied. Genetically, all H7-derived cell lines were identical to HepG2 cells. However, some liver-specific functions varied between the different sub-cloned lines. The H7-derived cell lines that were generated proved to be sub-cloned lines of HepG2. The problem of cross-contamination during cloning of cell lines appears to be not uncommon. We found that two out of six HepG2 isolates obtained from other laboratories were not derived from the same individual as the original HepG2 cells. Therefore, STR typing should be applied as a rapid and sensitive technique to determine and monitor the origin of cell lines and to safeguard against contamination. 相似文献
3.
Tyrosine sulfation: a post-translational modification of proteins destined for secretion? 总被引:9,自引:0,他引:9
Protein sulfation was studied in germ-free rats by prolonged in vivo labeling with [35S]sulfate. Specific sets of sulfated proteins were observed in all tissues examined, in leucocytes, and in blood plasma. No protein sulfation was detected in erythrocytes. Analysis of the type of sulfate linkage showed that sulfated proteins secreted into the plasma contained predominantly tyrosine sulfate, whereas sulfated proteins found in tissues contained largely carbohydrate sulfate. This implies some kind of selection concerning the intracellular processing, secretion, turnover or re-uptake of sulfated proteins which is responsible for the enrichment of tyrosine-sulfated proteins in the plasma. 相似文献
4.
5.
《Mutation Research/Reviews in Genetic Toxicology》1995,339(1):1-14
Vinyl chloride (VC) is a colorless gas with a mild, sweet odor. It is extensively used in the production of vinyl chloride polymer, copolymer resin, packaging materials, wire and cable coatings as well as in industrial and laboratory intermediates. It is toxic and also carcinogenic in experimental animals. The wide human exposure to this compound in different industries throughout the world causes great concern for human health. In the present review an attempt has been made to evaluate and update the genotoxic effects of vinyl chloride based on the available literature. 相似文献
6.
A synoptic review of the discoveries and studies of Chinese Mesozoic birds is provided in this paper. 40Ar/39Ar dating of several bird-bearing deposits in the Jehol Group has established a geochronological framework for the study of
the early avian radiation. Chinese Mesozoic birds had lasted for at least 11 Ma during about 131 Ma and 120 Ma (Barremian
to Aptian) of the middle and late Early Cretaceous, respectively. In order to further evaluate the change of the avian diversity
in the Jehol Biota, six new orders and families are erected based on known genera and species, which brings the total number
of orders of Chinese Mesozoic birds to 15 and highlights a remarkable radiation ever since the first appearance of birds in
the Late Jurassic. Chinese Early Cretaceous birds had experienced a significant differentiation in morphology, flight, diet
and habitat. Further examination of the foot of Jeholornis suggests this bird might not have possessed a fully reversed hallux. However, the attachment of metatarsal I to the medial
side of metatarsal II does not preclude trunk climbing, a pre-adaptation for well developed perching life of early birds.
Arboreality had proved to be a key adaptation in the origin and early evolution of bird flight, and the adaptation to lakeshore
environment had played an equally important role in the origin of ornithurine birds and their near-modern flight skill. Many
Chinese Early Cretaceous birds had preserved the direct evidence of their diet, showing that the most primitive birds were
probably mainly insectivorous and that specialized herbivorous or carnivorous (e.g., piscivorous) dietary adaptation had appeared
only in later advanced forms. The only known Early Cretaceous bird embryo fossil has shown that precocial birds had occurred
prior to altricial birds in avian history, and the size of the embryo and other analysis indicate it probably had a short
incubation period. Leg feathers probably have a wide range of distribution in early birds, further suggesting that leg feathers
had played a key role in the beginning stage of the flight of birds. Finally, the Early Cretaceous avian radiation can be
better understood against the background of their unique ecosystem. The advantage of birds in the competitions with other
vertebrate groups such as pterosaurs had probably not only resulted in the rapid differentiation and radiation of birds but
also the worldwide spreading of pterosaurs and other vertebrates from East Asia in the Early Cretaceous.
Selected from Vertebrata PalAsiatica 2006, 44 (1): 74–98 相似文献
7.
Compactin—a review 总被引:2,自引:0,他引:2
Compactin, a hypocholesterolemic molecule, is a competitive inhibitor of 3-hydroxy-3-methyl-glutaryl (HMG)-CoA reductase, which is a regulatory enzyme for cholesterol biosynthesis. The structural similarity and high affinity of the acid form of compactin and HMG, the natural substrate of enzyme, results in specific and effective inhibition of this enzyme. Inhibition results in reduced levels of mevalonic acid in the body, leading to pleiotropic effects. Various fungi have been used for the commercial production of compactin. Using different strategies for improving production levels, yields have been increased to around 900 times of the amount originally produced. Recently, the gene sequence responsible for compactin production has been cloned and sequenced. This review deals with the chemistry, mode of action, pharmacology, biosynthesis, and production of compactin. A comparative study of various reports dealing with the production of compactin is also included. 相似文献
8.
The development of design systems which ensure economic feasibility has been the focus of recent research in the manufacturing area. Traditional design and justification approaches have been cited as having shortcomings; thus, there have been a variety of modifications and enhancements developed. An approach that is conceptually different from the traditional approaches seeks the integration of the economic analysis within the design process. We denote this approach as thedesign justification method. This paper reviews literature related to the explicit and implicit integration of economic factors in the manufacturing system design process, followed by supporting issues for the implementation of the design justification concept. 相似文献
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10.
Ana D. Atanacković Ferdinand Šporka Bela Csányi Božica M. Vasiljević Jelena M. Tomović Momir M. Paunović 《Biologia》2013,68(2):269-277
The aim of this work is to discuss the distribution of Oligochaeta (Annelida) in the Danube River using the collections made by the Joint Danube Survey 2007 (JDS2) on more than 2800 km of the river. The basic faunistical features of the oligochaete assemblages were analysed with regard to three main sectors of the Danube (upper, middle and lower reaches, the last with the Danube Delta). A total of 52 oligochaete taxa have been recorded. Most of the observed species are typical of the potamon-type rivers in the region, and are well adapted to moderate-to-high organic load. The highest taxa richness and frequency of occurrence were observed among the Tubificidae family. Naididae, Propappidae, Enchytraeidae and Haplotaxidae had also low frequency. The upper reach of the Danube showed the lowest species richness, while the middle reach is characterised by its highest species richness. Construction of dams and regulation of the riverbed have resulted in an increase of limno(rheo)philic taxa which prefer slow-flowing and lentic zones. 相似文献
11.
Jørgen Kristiansen 《Hydrobiologia》1996,336(1-3):151-157
A survey is given on the various methods for dispersal of freshwater algae. Dispersal factors are either water or air, or
organisms — from beetles, dragonflies and mammals to birds, the latter being the most important group. The question of dispersal
distances is discussed, in relation to dispersal mechanisms and to the resistance of the algae to transport conditions. Man's
recent importance in algal dispersal is emphasized. 相似文献
12.
《Gene》1996,179(1):73-81
Tetrahydrobenzylisoquinoline alkaloids comprise a diverse class of secondary metabolites with many pharmacologically active members. The biosynthesis at the enzyme level of at least two tetrahydrobenzylisoquinoline alkaloids, the benzophenanthridine alkaloid sanguinarine in the California poppy, Eschscholtzia californica, and the bisbenzylisoquinoline alkaloid berbamunine in barberry, Berberis stolonifera, has been elucidated in detail starting from the aromatic amino acid (aa) l-tyrosine. In an initial attempt to develop alternate systems for the production of medicinally important alkaloids, one enzyme from each pathway (BBE, a covalently flavinylated enzyme of benzophenanthridine alkaloid biosynthesis and CYP80, a phenol coupling cytochrome P-450-dependent oxidase of bisbenzylisoquinoline alkaloid biosynthesis) has been purified to homogeneity, a partial aa sequence determined, and the corresponding cDNAs isolated with aid of synthetic oligos based on the aa sequences. The recombinant enzymes were actively expressed in Spodoptera frugiperda Sf9 cells using a baculovirus vector, purified and then characterized. Insect cell culture has proven to be a powerful system for the overexpression of alkaloid biosynthetic genes. 相似文献
13.
Patrik J. G. Henriksson Jeroen B. Guinée René Kleijn Geert R. de Snoo 《The International Journal of Life Cycle Assessment》2012,17(3):304-313
Purpose
As capture fishery production has reached its limits and global demand for aquatic products is still increasing, aquaculture has become the world’s fastest growing animal production sector. In attempts to evaluate the environmental consequences of this rapid expansion, life cycle assessment (LCA) has become a frequently used method. The present review of current peer-reviewed literature focusing on LCA of aquaculture systems is intended to clarify the methodological choices made, identify possible data gaps, and provide recommendations for future development within this field of research. The results of this review will also serve as a start-up activity of the EU FP7 SEAT (Sustaining Ethical Aquaculture Trade) project, which aims to perform several LCA studies on aquaculture systems in Asia over the next few years. 相似文献14.
15.
《Gene》1996,179(1):171-177
16.
Norman L. Biddington 《Plant Growth Regulation》1986,4(2):103-123
Mechanically-induced stress (MIS) occurs naturally in plants as the aerial parts are moved, usually by wind, but also by such agents as rain and animals. It can be induced indoors by various actions such as rubbing or bending the stem or shaking or brushing the entire shoot. The most noticeable effect of MIS is a reduction in stem, leaf or petiole length invariably resulting in plants which are smaller and more compact than unstressed controls. However, the response of other variables can often differ between species and there may be either increases or decreases in stem or petiole diameter, root: shoot weight ratio, chlorophyll content or drought resistance. Why species should differ in this way, and what is the endogenous control mechanism for MIS responses, are inanswered questions. Ethylene, which increases as a result of MIS in several species may cause some MIS responses such as increased stem diameter, epinasty or a change in sex expression. However, evidence suggests that MIS retardation of extension growth may equally be due to lower or supraoptimal auxin levels or lower gibberellin levels.The uses in the field of the growth promoter gibberellin or the growth retardant chlormequat chloride (CCC) appear to be examples of respectively reversing or stimulating MIS growth response. MIS may be applied indoors if short compact plants are needed, either for aesthetic purposes as with floral crops, or if hardier and more manageable plants are needed, such as seedlings for transplanting in the field. Much more research is needed to estimate the importance of MIS in the field and to assess how such knowledge may be used to improve crop yield. 相似文献
17.
Heike Wägele Annette Klussmann-Kolb Eva Verbeek Michael Schrödl 《Organisms Diversity & Evolution》2014,14(1):133-149
Opisthobranchia have experienced an unsettled taxonomic history. At the moment their taxonomy is in state of dramatic flux as recent phylogenetic studies have revealed traditional Opisthobranchia to be paraphyletic or even polyphyletic, allocating some traditional opisthobranch taxa to other groups of Heterobranchia, e.g. Pulmonata. Here we review the history of Opisthobranchia and their subgroups, explain their traditionally proposed relationships, and outline the most recent phylogenetic analyses based on various methods (morphology, single gene and multiple gene analyses, as well as genomic data). We also present a phylogenetic hypothesis on Heterobranchia that, according to the latest results, represents a consensus and is the most probable one available to date. The proposed phylogeny supports the Acteonoidea outside of monophyletic Euthyneura, the basal euthyneuran split into Nudipleura (Nudibranchia plus Pleurobranchoidea) and the recently established taxon Tectipleura. The latter divides into the Euopisthobranchia, containing most of the major traditional opisthobranch clades, and the Panpulmonata, with a mix of the former opisthobranch, putative allogastropod and pulmonate taxa. This “new euthyneuran tree” rejects the traditional taxa Opisthobranchia and Pulmonata, and, in particular, has profound implications for preconceived textbook scenarios of opisthobranch and pulmonate evolution, which must now be reconsidered. In the absence of systematic barriers, research communities—which have traditionally investigated marine and non-marine heterobranchs separately—need to interact and finally merge for the sake of science. 相似文献
18.
Transgenic fish, owing to a number of advantages which they offer over other species, are proving to be valuable model systems for the study of gene regulation and developmental genetics in addition to being useful targets for the genetic manipulation of commercially important traits. Despite having begun only a decade ago, the production of transgenic fish has become commonplace in a number of laboratories world-wide and considerable progress has been made. In this review, we initially consider the various regulatory elements and coding genes which have been used in fish, and subsequently discuss and compare both the transient and long-term fate and expression patterns of injected DNA sequences in the context of the different factors which are likely to have an effect on the expression of transgenes. 相似文献
19.
Environmental impacts of hybrid and electric vehicles—a review 总被引:2,自引:0,他引:2
Troy R. Hawkins Ola Moa Gausen Anders Hammer Str?mman 《The International Journal of Life Cycle Assessment》2012,17(8):997-1014