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Summary The spleen of the oriental fire-bellied toad, Bombina orientalis, consists of well-developed white pulp, separated from the lymphocytic marginal zone by the connective tissue boundary layer. Injection of peroxidase-conjugated rabbit anti-peroxidase revealed that these immune complexes were localized on the surface of acid-phosphatase-positive and non-specific-esterasepositive cells in the white pulp. The majority of immunecomplex-trapping cells were present around the blood vessels. Cell processes of some of these cells penetrated into the wall of blood vessels. The significance of the present findings is discussed with respect to the evolution of immune-complex-trapping cells in the spleen.  相似文献   

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Chen T  Orr DF  Bjourson AJ  McClean S  O'Rourke M  Hirst DG  Rao P  Shaw C 《Peptides》2002,23(9):1547-1555
Bradykinin and (Thr(6))-bradykinin have been identified in the defensive skin secretion of the fire-bellied toad, Bombina orientalis. The homologous cDNAs for both peptides were cloned from a skin library using a 3'- and 5'-RACE strategy. Kininogen-1 (BOK-1) contained an open-reading frame of 167 amino acid residues encoding four repeats of bradykinin, and kininogen-2 (BOK-2) contained an open-reading frame of 161 amino acid residues encoding two repeats of (Thr(6))-bradykinin. Alignment of both precursor nucleotide and amino acid sequences revealed a high degree of structural similarity. These amphibian skin kininogens/preprobradykinins are not biologically analogous to mammalian kininogens.  相似文献   

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We have sequenced a cDNA clone encoding a 26-kDa ferritin subunit, which was heavy chain homologue (HCH), in fall webworm, Hyphantria cunea. The HCH cDNA was obtained from the screening of a cDNA library using a PCR product. H. cunea ferritin is composed of 221 amino acid residues and their calculated mass is 26,160 Da. The protein contains the conserved motifs for the ferroxidase center typical for heavy chains of vertebrate ferritin. The iron-responsive element sequence with a predicted stem-loop structure is present in the 5'-untranslated region of ferritin HCH mRNA. The sequence alignment of ferritin HCH shows 68.9 and 68.7% identity with Galleria mellonella HCH (26 kDa ferritin) and Manduca sexta HCH, respectively. While G type insect ferritin vertebrate light chain homologue (LCH) is distantly related to H. cunea ferritin HCH (17.2-20.8%), the Northern blot analysis revealed that H. cunea ferritin HCH was ubiquitously expressed in various tissues and all developmental stages. The ferritin expression of midgut is more responsive to iron-fed, compared to fat body in H. cunea.  相似文献   

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Chen T  Shaw C 《Peptides》2003,24(6):873-880
The structural diversity of polypeptides in amphibian skin secretion probably reflects different roles in dermal regulation or in defense against predators. Here we report the structures of two novel trypsin inhibitor analogs, BOTI and BVTI, from the dermal venom of the toads, Bombina orientalis and Bombina variegata. Cloning of their respective precursors was achieved from lyophilized venom cDNA libraries for the first time. Amino acid alignment revealed that both deduced peptides, consisting of 60 amino acid residues, including 10 cysteines and the reactive center motif, -CDKKC-, can be affirmed as structural homologs of the trypsin inhibitor from Bombina bombina skin.  相似文献   

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Analyzing the Radiation of the Proenkephalin Gene in Tetrapods: Cloning of a Bombina orientalis Proenkephalin cDNA: A proenkephalin cDNA was cloned from the brain of the anuran amphibian, Bombina orientalis (Family: Discoglossidae). This cDNA is 1358 nucleotides in length, and contains an open reading frame that codes for 251 amino acids. Within the open reading frame there are seven opioid (YGGF) sequences. There were five Met-enkephalin (YGGFM) sequences that are flanked by sets of paired basic amino acid proteolytic cleavage sites and two C-terminally extended Met-enkephalin sequences: YGGFMRGY and YGGFMRF. No Leu-enkephalin sequences were found in B. orientalis proenkephalin. It was possible to align the amino acid sequences of proenkephalin from several vertebrate taxa (human, Australian lungfish, B. orientalis, Xenopus laevis, Spea multiplicatus) by inserting a minimum of nine gaps. This alignment was then used to analyze the corresponding nucleotides for each proenkephalin sequence using maximum likelihood. This analysis yielded a single tree. In this tree, the Australian lungfish sequence was the outgroup or the tetrapod ingroup. The amphibian sequences form a clade separate from the human sequence. The bootstrap value for the amphibian clade was 100%. Within the amphibian clade the Bombina sequence was the sister group to a clade composed of the X. laevis and S. multiplicatus sequences. The bootstrap value for the X. laevis/S. multiplicatus clade was 94%. Collectively, these data indicate that the sequence of Bombina proenkephalin may be more similar to the proposed ancestral anuran proenkephalin sequence, than either X. laevis or S. multiplicatus proenkephalin.  相似文献   

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A new amphibian cell line, Bor II, is described. It was initiated from Stage 20 embryos of the discoglossid frog, Bombina orientalis. In early passages the cell line had an epithelioid morphology. Beginning at or around subcultivation 16, a more fibroblastic cell type emerged and rapidly became predominant. These later passage cells were able to proliferate in low (1.0%) serum, displayed frequent overlaps, and lacked postconfluent inhibition of cell division. The cell line was unable to survive at 37 degrees C, but grew vigorously within a temperature range of 20 degrees to 30 degrees C. The presence of two distinctive marker chromosomes in an otherwise diploid karyotype should make these cells useful for nuclear transplantation studies.  相似文献   

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Wild-collected adults of Bombina orientalis are bright green dorsally and red to red-orange ventrally. As a prelude to an analysis of the differentiation of pigment cells in developing B. orientalis, we describe structural and chemical aspects of the fully differentiated pigment pattern of the “normal” adult. Structurally, differences between dorsal green and ventral red skin are summarized as follows: (1) Dorsal green skin contains a “typical” dermal chromatophore unit comprised of melanophores, iridophores, and xanthophores. Red skin contains predominantly carotenoid-containing xanthophores (erythrophores), and skin from black spot areas contains only melanophores. (2) In ventral red skin, there is also a thin layer of deep-lying iridophores that presumably are not involved in the observed color pattern. (3) Xanthophores of red and green skin are morphologically distinguishable from each other. Dorsal skin xanthophores contain both pterinosomes and carotenoid vesicles; ventral skin xanthophores contain only carotenoid vesicles. Carotenoid vesicles in dorsal xanthophores are much larger but less electron dense than comparable structures in ventral xanthophores. The presence of carotenes in ventral skin accounts for the bright red-orange color of the belly of this frog. Similar pigments are also present in green skin, but in smaller quantities and in conjunction with both colored (yellow) and colorless pteridines. From spectral data obtained for xanthophore pigments and structural data obtained from the size and arrangement of reflecting platelets in the iridophore layer, we attempt to explain the phenomenon of observed green color in B. orientalis.  相似文献   

11.
R. H. Kaplan 《Oecologia》1987,71(2):273-279
Summary Life history theory suggests that reproductive characteristics such as ovum size and clutch size should be well buffered against vararies of the environment. However, studies which demonstrate environmental sensitivity of reproductive characteristics are increasing in number, as are studies which find that maternal effects are responsible for much of the variation in developmental and growth rates in embryonic and larval fish and amphibians. The data reported here demonstrate that the environment, in terms of temperature and food availability that a specific individual encounters during vitellogenesis, exerts a strong influence on both egg size and number. Warmer temperatures and less food decrease ovum size, while colder temperatures and less food decrease clutch size. The variation in ovum size that is induced by the environment can exert a strong influence on variation in offspring development and growth and serve as an excellent model for studies on the evolution of developmental plasticity.  相似文献   

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The sequence of appearance of the 17 different skull bones in the oriental fire-bellied toad, Bombina orientalis, is described. Data are based primarily on samples of ten or 11 laboratory-reared specimens of each of 11 Gosner developmental stages (36–46) representing middle through late metamorphosis. Ossification commences as early as stage 37 (hind limb with all five toes distinct), but the full complement of adult bones is not attained until stage 46 (metamorphosis complete). Number of bones present at intermediate stages is poorly correlated with external morphology. As many as four Gosner developmental stages elapse before a given bone is present in all specimens following the stage at which it may first appear. The modal ossification sequence is frontoparietal, exoccipital, parasphenoid, septomaxilla, premaxilla, vomer, nasal, maxilla, angulosplenial, dentary, squamosal, quadratojugal, pterygoid, prootic, interfrontal, sphenethmoid, and mentomeckelian. Most specimens are consistent with this sequence, despite the poor correlation between cranial ossification and external development as assayed by Gosner stage. The timing of cranial ossification in Bombina orientalis differs in many respects from that described for two other, distantly related anurans, the leopard frog (Rana pipiens) and the western toad (Bufo boreas). These include the total number and sequence of appearance of bones, and the timing of ossification relative to the development of external morphology. Interspecific variation may reflect differences in the timing of the tissue interactions known to underlie skeletal differentiation and evolution.  相似文献   

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Diploid tadpoles of the discoglossid frog, Bombina orientalis, possess a distinctive rectangular network of epidermal melanophores. The ontogeny of this network was examined and utilized as a model for the comparison of tissue integrity and cellular interactions in diploid and haploid embryos. During the process of network formation in diploids, a variety of melano-phore-melanophore interactions was observed. These included temporary contacts between neighboring melanophore processes, deviations of processes toward neighboring melanophores, and lateral extensions between closely situated, parallel processes originating from different cell bodies. None of these intercellular interactions were seen in haploid embryos. Haploid melanophores displayed fewer cytoplasmic extensions, appeared to be randomly oriented, and failed to establish the ordered network seen in diploid embryos. It was also discovered that, in comparison with diploid tissues, relative densities of melanophores and epithelial cells were not uniformly regulated in haploid embryos. These findings are interpreted as indicating that haploid embryos possess fundamental cell and tissue defects, and that the “haploid syndrome” is likely based on more than one or a few defective physiological functions.  相似文献   

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Summary Impulse generation and propagation was previously shown to occur in skin epithelium of newt (Cynops orientalis) embryos during certain stages of development and to be correlated with morphological changes of gap junctions. These properties are not detected in embryonic epithelia explanted and grown in culture. However, early explants when transplanted to a host embryo develop conductivity, and relatively large gap junctions with loose arrangement of connexons occur as soon as the host embryo reaches the stage when conductivity is at its maximum. In contrast, morphological and physiological characteristics of impulse propagation are lost when the transplanted epithelium is extirpated from the host embryo and returned to in-vitro conditions. Therefore, it appears that impulse propagation is dependent not solely on the differentiation of epithelial cells but upon signals from non-epithelial (possibly mesodermal) tissue as well.  相似文献   

17.
The transfer of xylose from UDP-xylose to the core beta-linked mannose of N-linked oligosaccharides by beta1,2-xylosyltransferase (XylT) is a widespread feature of plant glycoproteins which renders them immunogenic and allergenic in man. Here, we report the isolation of the Arabidopsis thaliana XylT gene, which contains two introns and encodes a 60.2 kDa protein with a predicted type II transmembrane protein topology typical for Golgi glycosyltransferases. Upon expression of A. thaliana XylT cDNA in the baculovirus/insect cell system, a recombinant protein was produced that exhibited XylT activity in vitro. Furthermore, the recombinant enzyme displayed XylT activity in vivo in the insect cells, as judged by the acquired cross-reaction of cellular glycoproteins with antibodies against the beta1,2-xylose epitope. The cloned XylT cDNA as well as the recombinant enzyme are essential tools to study the role of beta1,2-xylose in the immunogenicity and allergenicity of plant glycoproteins at the molecular level.  相似文献   

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Using five restriction enzymes, geographical variation of mitochondrial DNA (mtDNA) in Bombina bombina and B. variegata was studied in samples from 20 locations. Each restriction enzyme produced a species-specific fragment pattern. B. bombina haplotypes A and B were closely related to each other. In contrast, haplotypes A and B of B. variegata formed two distinct lineages. A very distinctive haplotype (C) was found in the Carpathian Mountains, whereas two other haplotypes, D and E (differing by a single AvaI site), were present in western Europe and the Balkans, respectively. Populations polymorphic for haplotypes D and E occurred in the central Balkans where the haplotypes could replace each other clinally. mtDNA sequence divergence between B. bombina and B. variegata was estimated as 6.0-8.1% and 4.7-5.2% between type C and types D/E of B. variegata. The latter divergence is contrary to allozyme and morphological data that place the western and Carpathian B. v. variegata together (Nei's D = 0.07) and separate them from the Balkan subspecies B. v. scabra (Nei's D = 0.18). Broad interspecific correlation among morphology, allozymes and mtDNA types in European fire-bellied toads argues that, despite continuous hybridization (interrupted perhaps during Pleistocene glacial maxima), little or no mtDNA introgression between the species has occurred outside the narrow hybrid zones that separate these parapatric species.  相似文献   

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An expression vector has been generated using a gene highly expressed under conditions found in a typical fed-batch bioreactor process. The ferritin heavy chain (HC) gene exhibits higher levels of expression in the late stages of a fed-batch bioreactor than in the early stages. This property was considered advantageous for an expression vector, since the maximal cell density would coincide with maximal expression. The rat ferritin HC genomic region was isolated and converted into an expression vector where large segments of 5' and 3' flanking regions were included in an attempt to recreate the same high level of expression in stably transfected cells. Expression from the resulting ferritin HC vector was compared to vectors containing the commonly used strong promoters, CMV IE, and SV40 early promoter/enhancer, in the generation of stable transfectants. The ferritin HC vector was able to generate cell lines with significantly higher expression levels than those under the control of the viral promoters.  相似文献   

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