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1.
Collagen Synthesis on Polysomes <Emphasis Type="Italic">in vivo</Emphasis> and <Emphasis Type="Italic">in vitro</Emphasis> 总被引:12,自引:0,他引:12
Polysomes synthesizing both α1 and α2 collagen chains have been identified by means of an in vitro system for completion and release of nascent polypeptides. Their size indicates that the mRNA for α chains is monocistronic. 相似文献
2.
Two repeated DNA sequences isolated from a partial genomic DNA library of Helianthus annuus, p HaS13 and p HaS211, were shown to represent portions of the int gene of a Ty3 /gypsy retroelement and of the RNase-Hgene of a Ty1 /copia retroelement, respectively. Southern blotting patterns obtained by hybridizing the two probes to BglII- or DraI-digested genomic DNA from different Helianthus species showed p HaS13 and p HaS211 were parts of dispersed repeats at least 8 and 7 kb in length, respectively, that were conserved in all species studied. Comparable hybridization patterns were obtained in all species with p HaS13. By contrast, the patterns obtained by hybridizing p HaS211 clearly differentiated annual species from perennials. The frequencies of p HaS13- and p HaS211-related sequences in different species were 4.3x10(4)-1.3x10(5) copies and 9.9x10(2)-8.1x10(3) copies per picogram of DNA, respectively. The frequency of p HaS13-related sequences varied widely within annual species, while no significant difference was observed among perennial species. Conversely, the frequency variation of p HaS211-related sequences was as large within annual species as within perennials. Sequences of both families were found to be dispersed along the length of all chromosomes in all species studied. However, Ty3 /gypsy-like sequences were localized preferentially at the centromeric regions, whereas Ty1/ copia-like sequences were less represented or absent around the centromeres and plentiful at the chromosome ends. These findings suggest that the two sequence families played a role in Helianthusgenome evolution and species divergence, evolved independently in the same genomic backgrounds and in annual or perennial species, and acquired different possible functions in the host genomes. 相似文献
3.
T. Zhang 《In vitro cellular & developmental biology. Plant》2007,43(2):91-94
This study investigated the factors affecting in vitro flowering of Perilla frutescens. The shoots regenerated from cotyledonary and hypocotyl explants cultured on Murashige and Skoog (MS) medium supplemented
with benzyladenine (BA) and indole-3-acetic acid, each at 0.5 mg l−1, were excised and transferred to MS medium containing 30 g l−1 of sucrose, 8.25 g l−1 of ammonium nitrate, and 1.0 mg l−1 of BA. After 40 d of culture, 86.2% of shoots flowered and most of which self-fertilized in vitro and produced mature fruits with viable seeds. These seeds were germinated and plants were grown to maturity and flowered
in soil under greenhouse conditions. The in vitro flowering system reported in this study may facilitate rapid breeding of P. frutescens and offers a model system for studying the physiological mechanism of flowering. 相似文献
4.
DAVID M. GOLDENBERG ROSE A. PAVIA HANS J. HANSEN JACQUES P. VANDEVOORDE 《Nature: New biology》1972,239(93):189-190
NORMAL and neoplastic mammalian cells cultivated in vitro retain a number of functions that characterize their cellular origin, even after extensive passage1. It therefore seems reasonable to expect that cell products such as tumour-associated antigens could, if present from the outset, be retained in a demonstrable state when the tumour cells are cultivated outside the original host organism. The discovery by Gold and Freedman2 of an antigenic substance specific for entodermally-derived cancers of the digestive system, carcinoembryonic antigen (CEA), provides a suitable candidate for studying one such property related to a particular type of human cancer. It has been proposed, however, that tumour-specific antigens such as CEA are not indigenous to the tumours, but are glycoproteins produced elsewhere in the body and coating the tumour cells secondarily3. If this were the case, then human colonic cancer cells in long-term propagation in vitro should not synthesize this material. We now present evidence to the contrary. 相似文献
5.
Six pea (Pisum sativum L.) cultivars (Adept, Komet, Lantra, Olivin, Oskar, Tyrkys) were transformed via Agrobacterium tumefaciens strain EHA105 with pBIN19 plasmid carrying reporter uidA (β-glucuronidase, GUS, containing potato ST-LS1 intron) gene under the CaMV 35S promoter, and selectable marker gene nptII (neomycin phosphotransferase II) under the nos promoter. Two regeneration systems were used: continual shoot proliferation from axillary buds of cotyledonary node in vitro, and in vivo plant regeneration from imbibed germinating seed with removed testa and one cotyledon. The penetration of Agrobacterium into explants during co-cultivation was supported by sonication or vacuum infiltration treatment. The selection of putative transformants in both regeneration systems carried out on media with 100 mg dm−3 kanamycin. The presence of introduced genes was verified histochemically (GUS assay) and by means of PCR and Southern blot analysis in T0 putative transformants and their seed progenies (T1 to T3 generations). Both methods, but largely in vivo approach showed to be genotype independent, resulting in efficient and reliable transformation system for pea. The in vivo approach has in addition also benefit of time and money saving, since transgenic plants are obtained in much shorter time. All tested T0 – T3 plants were morphologically normal and fertile.This research was supported by the National Agency for Agricultural Research (grants No. QE 0046 and QF 3072) and Ministry of Education of the Czech Republic (grant No. ME 433). 相似文献
6.
7.
Ana Paula Chiaverini Pinto Alessandra Cristina B. A. Monteiro-Hara Liliane Cristina Liborio Stipp Beatriz Madalena Januzzi Mendes 《In vitro cellular & developmental biology. Plant》2010,46(1):28-33
Passiflora alata in vitro organogenesis was studied based on explant type, culture medium composition, and incubation conditions. The results indicated
that the morphogenic process occurred more efficiently when hypocotyl segment-derived explants were cultured in media supplemented
with cytokinin and AgNO3 incubated under a 16-h photoperiod. The shoot bud elongation and plant development were obtained by transferring the material
to MSM culture medium supplemented with GA3 and incubated in flasks with vented lids. Histological analyses of the process revealed that the difficulties in obtaining
plants could be related to the development of protuberances and leaf primordia structures, which did not contain shoot apical
meristem. Roots developed easily by transferring elongated shoots to 1/2 MSM culture medium. Plant acclimatization occurred
successfully, and somaclonal variation was not visually detected. The efficiency of this organogenesis protocol will be evaluated
for genetic transformation of this species to obtain transgenic plants expressing genes that can influence the resistance
to Cowpea aphid borne mosaic virus. 相似文献
8.
B. Cukrowska I. Motyl H. Kozáková M. Schwarzer R. K. Górecki E. Klewicka K. Śliżewska Z. Libudzisz 《Folia microbiologica》2009,54(6):533-537
Three Lactobacillus strains (LOCK 0900, LOCK 0908, LOCK 0919) out of twenty-four isolates were selected according to their antagonistic activity
against pathogenic bacteria, resistance to low pH and milieu of bile salts. Intragastric administration of a mixture of these
strains to Balb/c mice affected cytokine TH1-TH2 balance toward nonallergic TH1 response. Spleen cells, isolated from lactobacilli-treated mice and re-stimulated in vitro with the mixture of heat-inactivated tested strains, produced significantly higher amounts of anti-allergic tumor necrosis
factor- and interferon-γ than control animals whereas the level of pro-allergic interleukin-5 was significantly lower. Lactobacillus cells did not translocate through the intestinal barrier into blood, liver and spleen; a few Lactobacillus cells found in mesenteric lymph nodes could create antigenic reservoir activating the immune system. The mixture of Lactobacillus LOCK 0900, LOCK 0908 and LOCK 0919 strains represents a probiotic bacterial preparation with possible use in prophylaxis
and/or therapy of allergic diseases. 相似文献
9.
Cre/LoxP mediated chromosomal engineering in embryonic stem (ES) cells has a variety of applications, including the creation of model systems for studying aneuploidy. Targeted meiotic recombination (TAMERE) was proposed as a high efficiency in vivo alternative to effect Cre-mediated recombination, in which Cre recombinase under control of the Synaptonemal Complex 1 promoter is expressed during male meiosis in transgenic mice. TAMERE has been successfully used with LoxP sites up to 100 kb apart. We tested TAMERE for a chromosome engineering application in which LoxP sequences were integrated into sites 3.9 Mb apart on the same (cis) or opposite (trans) copies of mouse Chromosome 16 (MMU16). TAMERE was ineffective in generating either a deletion or a translocation in vivo. The TAMERE method may be of limited use for large genomic rearrangements. The desired translocation was achieved with an in vitro method that can be used in any ES cell line. Mice produced from the reciprocal duplication/deletion of MMU16 in a region homologous to human chromosome 21 provide models that are useful in studies of Down syndrome. 相似文献
10.
Jiu-Cun Wang Syeling Lai Xinjian Guo Xuefeng Zhang Benoit de Crombrugghe Sonali Sonnylal Frank C Arnett Xiaodong Zhou 《Arthritis research & therapy》2010,12(2):R60
Introduction
SPARC is a matricellular protein, which, along with other extracellular matrix components including collagens, is commonly over-expressed in fibrotic diseases. The purpose of this study was to examine whether inhibition of SPARC can regulate collagen expression in vitro and in vivo, and subsequently attenuate fibrotic stimulation by bleomycin in mouse skin and lungs. 相似文献11.
We have developed a protocol for the in vitro propagation of the genus Clivia. Shoots were regenerated when fragments of the peduncle-pedicel junction (PP junction) from young inflorescences were used as explants. The optimal media for PP junction were Murashige and Skoog (MS)-based medium containing 10 M of 6-benzyladenine (BA) and 10 M of 2,4-dichlorophenoxyacetic acid (2,4-D) or MS supplemented with 5 M BA, 10 M -naphthaleneacetic acid (NAA), 250 mg l-1 glutamine and 500 mg l–1 casein hydrolysate and their usage depended on the breeding lines. Multiplication from initiations and in vitro seedlings was the best when the explants were cut longitudinally through the meristem and placed on MS plus 44 M BA. Plantlets were transferred on to hormone -free MS medium with charcoal for rooting. 相似文献
12.
SV40 virus DNA transcribes differently in vitro from in vivo. In a series of parallel experiments, the in vitro and in vivo single-stranded DNAs are shown to differ in structure. 相似文献
13.
Summary Shoot apex, nodal, and leaf explants of Stevia rebaudiana Bertoni can regenerate shoots when cultured on Murashige and Skoog (MS) medium supplemented with 6-benzyladenine (BA; 8.87
μM) and indole-3-acetic acid (5.71 μM). Rooting of the in vitro-derived shoots could be achieved following subculture onto auxin-containing medium. A survival rate of 70% was recorded at
the hardening phase on the substrate cocopeat. The presence of the sweet diterpene glycosides, viz. stevioside and rebaudioside,
was confirmed in the in vitro-derived tissues of Stevia using HPTLC techniques. Callus cultured on agar-solidified MS medium supplemented with BA (8.87 μM) and indole-3-butyric acid (9.80 μM) showed the highest sweetener content. 相似文献
14.
The effect of various hormonal combinations on regeneration of shoots and roots from meristem-derived callus of Crocus sativus L. and activities of antioxidant enzymes have been studied. The most efficient regeneration occurred with 1.0 mg dm−3 1-naphthaleneacetic acid (NAA) + 1.0 mg dm−3 thidiazuron and 1.0 mg dm−3 NAA + 2.0 mg dm−3 kinetin. For sprouting, regenerated shoot were subcultured on Murashige and Skoog medium containing 1.0 mg dm−3 NAA + 1.0 mg dm−3 benzylaminopurine (BAP). Protein content and superoxide dismutase activity decreased in regenerated shoots and roots and
increased in sprouting shoots, while catalase (CAT), peroxidase (POX) and polyphenol oxidase (PPO) activities increased during
organogenesis and decreased in sprouting shoots. High CAT and PPO activities were detected in regenerated roots, whereas high
POX activity was observed in regenerated shoot. 相似文献
15.
16.
Ordered and Preferential Initiation of Ribosomal RNA Synthesis <Emphasis Type="Italic">in vitro</Emphasis> 总被引:4,自引:0,他引:4
D. E. PETTIJOHN 《Nature: New biology》1972,235(59):204-206
17.
Induction of Antibody Synthesis by Purified Immunogenic RNA <Emphasis Type="Italic">in vitro</Emphasis> 总被引:2,自引:0,他引:2
WE have described an RNA fraction derived from phenol-extracted livers of immunized rabbits, which induced specific antibody production when mixed with normal rabbit spleen cells in vitro1,2. Similar fractions have been described by others using spleen, lymph node or peritoneal exudate cells of mice, rats or rabbits3–12 as sources of the RNA fraction. In all cases it has been assumed that the RNA-donor cell type was a macrophage. Considerable controversy has been generated by these experiments and data have been published to show that (a) the RNA is neither specific13 nor newly synthesized14 and (b) the RNA fraction contains antigen or fragments thereof15–18. Here we show that the data obtained with the rabbit-DNP system2 extend to another laboratory model, the mouse-sheep red blood cell (RBC) system. Our earlier work1,2 suggested that the immunogenic RNA is produced in the macrophage cell, that it is specific and that it is confined to a discrete fraction of the extractable RNA. For these reasons we thought it desirable (a) to compare directly the capacities of both liver and spleen tissue RNA extracts to induce antibody-plaque-forming cells in vitro, (b) to compare the effects of RNAase and pronase on the immunogenic capacity of the RNA fraction and (c) to investigate the distribution of the immunogenic RNA fraction relative to the total RNA fractions. 相似文献
18.
Polyamines are ubiquitous polycationic compounds that mediate fundamental aspects of cell growth, differentiation, and cell
death in eukaryotic and prokaryotic organisms. In plants, polyamines are implicated in a variety of growth and developmental
processes, in addition to abiotic and biotic stress responses. In the last decade, mutant studies conducted predominantly
in Arabidopsis thaliana revealed an obligatory requirement for polyamines in zygotic and somatic embryogenesis. Moreover, our appreciation for the
intricate spatial and temporal regulation of intracellular polyamine levels has advanced considerably. The exact molecular
mechanism(s) through which polyamines exert their physiological response remains somewhat enigmatic and likely serves as a
major area for future research efforts. In the following review, we discuss recent advances in the plant polyamine field,
which range from metabolism and mutant characterization to molecular genetics and potential mode(s) of polyamine action during
growth and development in vitro and in vivo. This review will also focus on the specific role of polyamines during embryogenesis and organogenesis. 相似文献
19.
Escherichia coliL-asparaginase, an antileukaemic agent in man1, inhibits in vitro mitogen or antigen-induced blastogenesis in man2,3 and in animals (M. Bennett, E. G. Mayhew and T. Han, unpublished data) and suppresses bone-marrow derived antibody precursor cells in the mouse4. We now report that another L-asparaginase preparation—from Erwinia carotovora—also possesses antileukaemic activity5,6 and has a more pronounced immunosuppressive effect on in vitro blastogenesis than the E. coli enzyme. 相似文献
20.
The ten mRNA species synthesized in vitro by reovirus-associated RNA polymerase contain the diphosphate, ppG, at the 5′-termini. The enzyme re-initiates continuously and digestion of the products with pancreatic RNAase releases predominantly ppGpUp from the 5′-ends. 相似文献