首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 582 毫秒
1.
One cultivar (GR876) and two advanced Ohio soft red winter wheat lines (OH413 and OH414), with Kavkaz in their pedigrees, were examined for the presence of the Kavkaz, 1RS/1BL rye/wheat chromosome translocation. Another advanced line (OH416), with Amigo in its pedigree, was examined for the presence of the Amigo, 1RS/1AL translocation. Only two satellited chromosomes were observed in most mitotic root-tip cells from GR876, OH413, and OH414, compared to four in most cells from OH416. Heteromorphic bivalents were observed in most PMCs from hybrids produced by crossing GR876, OH413, and OH414 as females to Chinese Spring. No heteromorphic bivalents were observed in PMCs from OH416 x Chinese Spring hybrids. When GR876 and the Ohio lines were hybridized with Chinese Spring dimonotelosomic-1B, telosomic trivalents, consisting of the short- and longarm telosomes paired with chromosome 1B, were only observed in PMCs from 43-chromosome hybrids involving OH416. The long-arm telosome paired with the translocation chromosome, while the short-arm telosome remained unpaired in all other 43-chromosome hybrids. Separation of gliadin proteins from GR876 and the Ohio lines by PAGE revealed that secalin bands for GR876, OH413, and OH414, migrated similarly to the secalins for Kavkaz. Bands for OH416, identified as possible secalins, migrated similarly to those for Amigo. Cultivar GR876 and advanced Ohio soft red winter wheat lines OH413 and OH414 carry the Kavkaz translocation, while OH416 carries the Amigo translocation.Communicated by K. Tsunewaki  相似文献   

2.
3.
A suitable procedure for the production of human monokines was defined as differentiation-induction culture. Human monocytic leukemia THP-1 cells were well-differentiated from nonfunctional promonocytes into macrophage-like cells by the induction with a combination of mezerein, retinoic acid, and aMycoplasma fermentans extract. The differentiated THP-1 cells secreted a high amount of macrophage differentiation-inducing factor (DIF) activity and concomitantly produced other known monokines, such as tumor necrosis factor- (TNF-), interleukin-1 (IL-1) and interleukin-1 (IL-1), into the medium. These results suggest that other novel human monokines may also be found in the conditioned medium of THP-1 cells induced by the differentiation-induction culture conditions defined in this study. Macrophage DIF was purified to homogeneity and NH2-terminal amino acid sequence analysis revealed that macrophage DIF is very similar or identical to human leukemia inhibitory factor (LIF). The cDNA encoding human LIF was isolated using the polymerase chain reaction, and a clone producing 3.7 g/106 cells day recombinant LIF was selected from Chinese hamster ovary (CHO) cells which were transfected with the LIF cDNA. The recombinant LIF production in CHO cells was quantified using MTT reduction assay with M1 cells.  相似文献   

4.
5.
1.  A series of CS revertants has been selected from various strains (both + and ) carrying a CR mitochondrial mutation at the RIB1 locus. The properties of mitochondrial recombination exhibited by these CS revertants in various crosses, have been examined systematically. The allele of the CS revertants has been defined in crosses with + and tester strains using two criteria: the polarity of recombination and a new criterium called relative output coefficient. We found that mutations of appear frequently associated with the mutations at the RIB1 locus selected from strains but not with those selected from + strains. A new allelic form of (n) which had not been found amongst wild type yeast strains is characterised. Similarly n mutation was found frequently associated with CR mutants at the RIB1 locus selected from CS strains but not with those selected from + CS strains. The n mutants, and the + and strains, explain the groups of polarity previously observed by Coen et al. (1970).
2.  Main features of mitochondrial crosses with n strains (+×n, ×n and n×n) are analysed. Recombination is possible between the different mitochondrial genetic markers. No high polarity of recombination is observed and the frequency of recombinants are similar to those found in homosexual crosses (+×+ and ×). A striking property, observed for the first time, exists in crosses between + +×n CS strains and some CREO mutants: the CREO are unable to integrate by recombination their CR allele into the + mit-DNA of CS strains while being capable of integrating it into + CS or CS genomes.
3.  It is proposed that the locus is the site of initiation of non reciprocal recombination events, the +/ pairing specifically initiates the non-reciprocal act while +/n or /n pairings do not.
4.  The molecular nature of the n mutation and its bearing on the structure of the locus are discussed. It is suggested that n mutations correspond to macrolesions (probably deletions) of a segment of the mit-DNA covering the and RIB1 loci. If n is a partial deletion of the sequence the + could be an additionnal deletion of the n sequence.
5.  The occurrence of spontaneous CR and ER mitochondrial mutations has been analysed by the Luria and Delbrück fluctuation test in and n isonuclear strains. Results of these tests indicate that an intracellular selection of resistant copies preexisting the action of the antibiotic occurs.
  相似文献   

6.
7.
8.
9.
Is there a way to talk about making culture without making enemies?   总被引:1,自引:0,他引:1  
We are seeing the beginnings of a process of folkloricization of various Tukanoan cultural traits. Perhaps in the future we shall see the commoditization of them. Elsewhere in the hemisphere various interest groups, including indigenous groups themselves, package and promote Indianness. The cultural forms that are retained from earlier traditions can therefore totally change in meaning. This poses problems when we talk about cultures using an organic model, because we find we cannot describe these processes in other than negative language. Both anthropologists and pro-Indian activists at times find it academically and/or politically expedient to talk of culture as enduring over time: while changing, these cultures are nonetheless seen as remaining the same in some fundamental ways. But when, as is beginning to occur in the Tukanoan case, traits are retained, cast aside or redefined as part of a self-conscious awareness and promotion of a particular kind of Indian identity as a political strategy, the meaning of these traits has often radically changed. We cannot use a quasi-biological model to account for these similarities over time.Since resemblances between earlier forms of Tukanoan culture and later forms may be superficial, conceiving of a culture in terms of traits that persist over time can be misleading. We need to think of culture change over relatively short periods of time in a more dynamic fashion, rather than as either the same or syncretized or lost. We need to see Tukanoans and others as creating and improvising, rather than possessing, culture. And we need to create and invent models and metaphors that analyze this process in nonderogatory terms.  相似文献   

10.
11.
Summary The nature of the association of U1 RNA with rapidly sedimenting RNP structures in rat hepatoma nuclei was investigated. The effects of salt and proteinase K treatment on the stability of this bound form of U1 RNA were studied using sucrose density gradient analyses. Quantitation of the amount of U1 RNA remaining associated with large structures after treatment was used to assess the relative contribution of protein-protein(and protein-RNA) versus RNA-RNA interactions. Forty-eight percent of the total nuclear U1 RNA released by sonication was found in a bound form when the sonicate was centrifuged through gradients containing 50 mM NaCl. Fifty percent of this bound U1 RNA remained associated with rapidly sedimenting RNPs when the NaCl concentration was raised to 500 mM. To assess the contribution of protein independent interactions, large RNPs were completely deproteinized and their RNA moieties were then recentrifuged on gradients. By this analysis, 27% of the U1 RNA originally bound to hnRNPs was associated with rapidly sedimenting (>30 S) RNA (at 50 mM NaCl) suggesting their association by RNA-RNA hydrogen bonds. When the concentration of NaCl was 500 mM, 31% of the U1 RNA was associated with large RNA. Hence, approximately 30% of the U1 RNA molecules originally bound (or about 15% of the total nuclear U1 RNA) were found to be associated by RNA-RNA hydrogen bonds while the remainder of the binding of U1 RNP to hnRNP was by protein-protein and/or protein-RNA interactions.  相似文献   

12.
13.
14.
15.
16.
Uptake kinetics of nitrogen derived from sewage–seawater mixtures (2.5–20% v/v effluent) were determined in the laboratory for Ulva rigida (Chlorophyceae) native from Bahía Nueva (Golfo Nuevo, Patagonia, Argentine). In terms of nitrogen concentration, experimental enrichment levels varied between 53.7 and 362.3M of ammonium and between 0.77 and 6.21M of nitrate+nitrite. Uptake rates were fitted to the Michaelis–Menten equation, with the following kinetic parameters: ammonium: Vmax = 591.2molg–1h–1, K s=262.3M, nitrate+nitrite: V max=12.9molg–1h–1, K s=3.5M). Both nutrients were taken up simultaneously, but ammonium incorporation was faster in all cases. The results show a high capability of Ulva rigida to remove sewage-derived nitrogen from culture media. In the field, most of the nitrogen provided by the effluent would be tied up in algal biomass, supporting low nitrogen levels found at a short distance away from the source.  相似文献   

17.
Beobachtungen über Nest und Nestbautechnik von Winter- und Sommergoldhähnchen(Regulus regulus, R. ignicapillus) im Freiland und in Volieren zeigen:
1.  Die Neststandorte von WG und SG gleichen einander, ihre Brutreviere können sich überlappen.
2.  Das Nest zeigt 3 deutlich getrennte Schichten. Die Außenschicht besteht aus Spinnstoff, Moos, Flechten — Moose (bei WG auch Flechten) bilden die Mittelschicht, Federn und Haare die Polsterung. Hochgebirgsnester weisen gegenüber Mittelgebirgsnestern einen Materialzuwachs besonders in der Mittel- und Polsterschicht auf.
3.  Der Nestbau dauert ca. 20 Tage, Zweitnester können rascher entstehen.
4.  Die Bautechnik wechselte mit fortschreitendem Bau. Baubewegungen für Grundgerüst, Rohbau und Polsterung waren verschieden. 14 (WG) bis 15 (SG) Baubewegungen konnten unterschieden und den 3 Bauphasen zugeordnet werden: a) Bei der Anlage des Grundgerüsts wurden die Tragästchen mit Spinnstoff bedeckt/umwickelt. Die Gespinste wurden dabei abgerieben, verspannt, und beim Außen säubern mit dem Ast fest verbunden. b) Der Rohbau entstand durch weiteres Einbringen von Spinnstoff und zunehmend häufiger Moosen/Flechten. Die Wände wurden durch Wegschieben (bzw. Einvibrieren) der Baustoffe geformt und gefestigt, beim WG auch maskiert, der Boden durch Unten säubern geschlossen. Zuletzt eingestopfte Moose der Mittelschicht wurden verstrampelt, der Rand durch Verstreichen verstärkt und geglättet. c) Die Mulde wurde mit Federn/Haaren ausgekleidet, das Polstermaterial durch Strampeln geordnet, sperrige oder auffallende Polsterstoffe wieder entfernt. Gleichzeitig wurde der Nestrand eng zusammengezogen, die Tragästchen von Spinnstoffresten gesäubert; SG verdeckten durch aufgesteckte Federn die Nestmulde.
5.  Die beiden Arten stimmten auch in ihrer Nestbautechnik weitgehend überein. Auffälligster Unterschied war, daß sich SG am Nestbau nicht beteiligen und nur begleiten. Doch führten juvenile beider Arten fast alle Baubewegungen spielerisch aus. Unterschiede gab es auch in den Baubewegungen der : SG vibrierten beim Wegschieben (2 e) und Randverstreichen (2 g) und verdeckten die Mulde durch aufgesteckte Federn.
  相似文献   

18.
19.
Using degenerate primers based on published 2-microglobulin sequences we were able to obtain an expected 111 base pairs (bp) polymerase chain reaction (PCR) fragment from tilapia genomic DNA. The sequence of this fragment showed a high degree of similarity to mouse 2-microglobulin at the protein level. We used these primers in an anchored PCR to obtain a 213 bp PCR fragment from a carp cDNA library. This was then used to clone a full-length 2-microglobulin cDNA from carp. The carp sequence showed the highest similarity to rabbit 2-microglobulin. Both sequences showed strong similarities to all previously published vertebrate 2-microglobulin sequences. The predicted protein secondary structure of both the carp and tilapia clones was almost identical to the corresponding regions of previously known vertebrate 2-microglobulin protein sequences. When either the carp or tilapia probes were used against corresponding northern blots, they hybridized to a message of approximately 800–1000 bases long, which corresponds to the previously published lengths of 2-microglobulin mRNAs. Southern blotting indicated that 2-microglobulin was encoded by a single copy gene in both cases. Phylogenetic analysis indicated that the sequences were related to the 2-microglobulins of higher vertebrates but grouped together in an ancestral position.The nucleotide sequence data reported in this paper have been submitted to the GenBank nucleotide sequence database and have been assigned the accession numbers L05536 (carp), L05537 (tilapia).  相似文献   

20.
Summary The natural-killer(NK)-cell-mediated cytotoxicity to syngeneic tumor cells can be augmented by in vivo priming and subsequent in vitro challenge with the streptococcal preparation OK432. Supernatants of cocultures of spleen cells with OK432 contained interleukin-2 (IL-2) and interferon (IFN), mainly IFN-. As the anti-(mouse IFN-) monoclonal antibody but not anti-(mouse IFN-) antibody inhibited the induction of activated NK cells with OK432, the IFN- participated in this response. The enhancement of NK cell activity and production of IL-2 were partially inhibited by the pretreatment of spleen cells with mitomycin C or irradiation, and were completely abolished by pretreatment with actinomycin D. The IL-2 activity after treatment with various metabolic inhibitors ran parallel to the NK activity in a system augmented with OK432. The activity of incubated spleen cells with IL-2 receptors was increased by OK432 treatment, and the NK cell and IFN activities of supernatants were also abrogated by the treatment with anti-(mouse IL-2 receptor) monoclonal antibody, to block the interaction between IL-2 and these receptors of effector cells. The panning method clarified that the incubated spleen cells with IL-2 receptors are responsible for the production of IFN-. These results suggest that IL-2 plays a major role in inducing the activated NK cells from murine spleen cells primed in vivo and subsequently challenged in vitro with OK432, by the production of IFN-.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号