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51.
Cell suspensions were initiated from plumule derived calli ofSpinacia oleracea. Some of these cell lines could be maintained in culture for at least three years without a reduced growth rate. A high yield of protoplasts was obtained from the cell suspensions. When protoplasts were cultured in Murashige and Skoog medium with naphthaleneacetic acid and 6-benzyladenine, cell wall formation was observed after three days. The cultured protoplasts produced numerous cell-clusters within two weeks. However only protoplasts isolated from suspensions which were in a rapidly dividing phase were able to divide with a high frequency and give rise to callus colonies. 相似文献
52.
H Saito J Ozaki J Yasuda M Kurokawa T Tomita Y Okubo M Tanaka S Nakagawa 《Japanese journal of medical science & biology》1984,37(2):83-95
The utility of the Groupamatic MG50 system for quantitative expression of agglutination in terms of continuous response was studied. By use of the characteristics of the design of this system, in which the change in voltage reflects the degree of agglutination, a linear regression relationship between the log ratio of light flux obtained by transformation of the voltage and the log dilution factor of the serum was demonstrated. The availability of the parallel line assay method to the standardization of the blood grouping antisera was also described. 相似文献
53.
mRNA polyadenylate-binding protein: gene isolation and sequencing and identification of a ribonucleoprotein consensus sequence. 总被引:111,自引:30,他引:81
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S A Adam T Nakagawa M S Swanson T K Woodruff G Dreyfuss 《Molecular and cellular biology》1986,6(8):2932-2943
We identified and produced antibodies to the major proteins that interact with poly(A)+ RNAs in the yeast Saccharomyces cerevisiae. The major proteins which were cross-linked by UV light to poly(A)+ RNA in intact yeast cells had apparent molecular weights of 72,000, 60,000, and 50,000. The poly(A) segment of the RNA was selectively cross-linked to the 72,000-molecular-weight protein (72K protein). Mice immunized with purified UV-cross-linked RNA-protein (RNP) complexes produced antibodies to the three major RNP proteins. A yeast genomic DNA library constructed in the lambda gt11 expression vector was screened with the anti-RNP serum, and recombinant bacteriophage clones were isolated. One recombinant phage, lambda YPA72.1, bearing a 2.5-kilobase insert, produced a large beta-galactosidase-RNP fusion protein. Affinity-selected antibodies from the anti-RNP serum on this fusion protein recognized a single 72K protein which was cross-linked to the poly(A) segment of RNA in the intact cell. Furthermore, the fusion protein of lambda YPA72.1 had specific poly(A)-binding activity. Therefore, lambda YPA72.1 encodes the 72K poly(A)-binding protein. Immunofluorescence microscopy showed that this protein was localized in the cytoplasm. Hybrid-selected mRNA translated in vitro produced the 72K poly(A)-binding protein, and mRNA blot analysis detected a single 2.1-kilobase mRNA. DNA blot analysis suggested a single gene for the poly(A)-binding protein. DNA sequence analysis of genomic clones spanning the entire gene revealed a long open reading frame encoding a 64,272-molecular-weight protein with several distinct domains and repeating structural elements. A sequence of 11 to 13 amino acids is repeated three times in this protein. Strikingly, this repeated sequence (RNP consensus sequence) is highly homologous to a sequence that is repeated twice in a major mammalian heterogeneous nuclear RNP protein, A1. The conservation of the repetitive RNP consensus sequence suggests an important function and a common evolutionary origin for messenger RNP and heterogeneous nuclear RNP proteins. 相似文献
54.
Fukuo Nakagawa Bradley A. Schulte Dr. Samuel S. Spicer 《Cell and tissue research》1986,245(3):579-589
Summary Paraffin sections of the trigeminal nerve root of the rat, and human spinal nerve root and trigeminal ganglion were stained with a battery of lectin-horseradish peroxidase conjugates to localize and characterize glycoconjugate (GC) in situ. In the rat the myelin sheath of the peripheral segment contained GC with sialic acid most probably linked to the penultinate disaccharide galactose(1 4)-N-acetylglucosamine (Gal(1 )-GlcNAc), and complex type N-glycosidic side chains. The myelin sheath in the central segment differed in containing little if any of the GC named above and in containing GC with terminal -Gal linked to N-acetylgalactosamine (GalNAc), terminal GalNAc and fucose. Schwann cells stained for GC with GlcNAc or mannose whereas oligodendroglia stained for GC with the terminal disaccharide Gal-(1 3)-GalNAc and N-glycosidic side chains, especially in presumed Golgi zones, but also in processes continued as the outer myelin sheath. The human myelin sheath in the central segment differed from that of the rat in not staining with lectins specific for fucose and terminal GalNAc. Sialic acid and terminal -Gal were seen in the human central segment but these sugars appeared to bind to astroglial structures rather than to the myelin sheath as in the rat. Astrocytes in both rat and man were stained by two fucose-binding lectins. Several lectins revealed affinity for GC in the neurilemmal sheath, and staining of this structure was stronger in the human specimens. Neurons in the human trigeminal ganglion ranged from unstained to strongly positive for fucoconjugate in cytoplasmic bodies and plasmalemma. Positive ganglion cells gave rise to unmyelinated fibers which also stained for fucoconjugate. Remak fibers and their extensions into the substantia gelatinosa of the human spinal cord stained strongly for content of fucose.The stronger lectin affinity for N-glycosidic core sugars in the peripheral as compared with the central segment suggests that lectins localize Po protein in peripheral myelin. The reactivity for several sugars in the central segment can possibly be attributed to myelin-associated glycoprotein (MAG) of central myelin, but lectin staining for GalNAc shows in addition a biochemically unrecognized GC with O-glycosidic linked oligosaccharides in myelin. The lectin cytochemistry indicates that the 170 K Dalton glycoprotein with PNA affinity obtained from rat sciatic nerves occurs in nodes of Ranvier.This research was supported by NIH Grants AM-10956, HL-29775 and United Health and Medical Research Foundation of South Carolina, Inc. Grant No. 79 相似文献
55.
Effects of auxin and cytokinin on cell growth and alkaloid production in cell suspension cultures of Thalictrum minus were examined in an attempt to increase the productivity of a medicinal compound, berberine. In Linsmaier and Skoog medium containing auxin such as 2,4-D (1 M), the cultured cells grew rapidly, producing little berberine. On the other hand, the berberine-producing activity was remarkably enhanced by simultaneous administration of auxin and cytokinin, although cell growth was inferior. In particular, for the combination of NAA (60 M) and 6-benzylaminopurine (10 M), the yield of berberine was as high as 20 mg/30 ml medium after 2 weeks of culture. Furthermore, most of the berberine produced by the cells was released into the liquid medium, in which an excess of berberine crystallized. The results of the present experiments are suggestive of an advantage in adopting a two-stage culture method for the production of berberine in fermentor systems.Abbreviations LS
Linsmaier and Skoog
- 2,4-D
2,4-dichlorophenoxyacetic acid
- NAA
1-naphthaleneacetic acid
- IAA
indole-3-acetic acid
- IBA
indole-3-butyric acid
- BAP
6-benzylaminopurine 相似文献
56.
IMP dehydrogenase. II. Purification and properties of the enzyme from Yoshida sarcoma ascites tumor cells 总被引:1,自引:0,他引:1
The preceding paper showed that IMP dehydrogenase [IMP:NAD+ oxidoreductase, EC 1.2.1.14] tended to form a precipitable complex(es) through ionic and hydrophobic interactions. On the basis of these observations, a method was developed for purification of IMP dehydrogenase from Yoshida sarcoma ascites cells. On SDS-polyacrylamide gel electrophoresis, the purified preparation (1.19 U/mg protein) appeared homogeneous and its minimum molecular weight was estimated to be 68K daltons. Amino acid analyses indicated a subunit molecular weight of 68,042. Molecular sieve chromatography in the presence of 10% (NH4)2SO4 showed that the molecular weight of the native enzyme was 127K daltons. These values indicate that the native enzyme is composed of two identical subunits. However, the purified enzyme gave 4 protein bands on polyacrylamide gel electrophoresis under non-denaturing conditions, and appeared as a single fraction in the vicinity of the void volume on Ultrogel AcA 34 column chromatography at low salt concentration, indicating that its molecular weight exceeded 200K daltons. These findings indicate that the enzyme tends to aggregate owing to its own physicochemical characteristics. The Km values for IMP and NAD were calculated to be 12 and 25 microM, respectively, and the Ki values for XMP, GMP, and AMP to be 109, 130, and 854 microM, respectively. The purified enzyme showed full activity in the presence of K+, and K+ could be partially replaced by Na+. PCMB inactivated the enzyme, but the activity was completely restored by the addition of DTT. Cl-IMP also inactivated the enzyme and IMP prevented this inactivation.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
57.
58.
Linear, Single-Stranded Deoxyribonucleic Acid Isolated from Kilham Rat Virus 总被引:9,自引:9,他引:0
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Kilham rat virus (KRV) was grown in a rat nephroma cell line and was purified by two isopycnic centrifugations in cesium chloride. The virus contains single-stranded deoxyribonucleic acid (DNA) with a molecular weight of approximately 1.6 x 10(6). The DNA was extracted from the virion by both phenol extraction and by 2% sodium dodecyl sulfate at 50 C. KRV DNA, extracted by both procedures, was observed in an electron microscope by using a cytochrome c or diethylaminoethyldextran monolayer. The DNA was also exposed to exonuclease I, an enzyme which hydrolyzes specifically linear, single-stranded DNA. Hydrolysis of 70 to 80% of the DNA was observed. Both the enzymatic and the electron microscope studies support the conclusion that extracted KRV DNA is a single-stranded, linear molecule. The length of the DNA was measured in the electron microscope and determined to be 1.505 +/- 0.206 mum. 相似文献
59.
Electron Microscopic Observations on the Ribonucleic Acid of Murine Leukemia Virus 总被引:12,自引:9,他引:3
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The ribonucleic acid (RNA) of murine leukemia virus (MLV) Rauscher strain was observed by the aid of electron microscopy with the use of the protein monolayer technique. RNA was observed directly after release from virus particles or after isolation by sedimentation in sucrose density gradients. Molecules were found in an extended linear form. Many of the RNA filaments released by detergent treatment contained curled regions, suggesting the linear filaments were originally coiled within the virus particle. The relationship of the curled areas to the containment of the RNA within the virus particle is discussed, and a mechanism for the inclusion of RNA in the budding virion is proposed. Treatment of the extended MLV-RNA with dimethyl sulfoxide resulted in the collapse of the molecule forming a tangled complex. Treatment with urea or heating at 50 C in 3 mm NaCl also produced this effect. Also under the conditions in which MLV-RNA was linear, RNA from Rous sarcoma virus also was linear, but Newcastle disease virus RNA and ribosomal RNA of rat liver had collapsed structures. The results indicated that the RNA of MLV, and perhaps other RNA-containing tumor viruses, has a specific unique conformation dependent upon hydrogen bonds. 相似文献
60.
Sporulation, Heat Resistance, and Biological Properties of Clostridium perfringens 总被引:6,自引:3,他引:3
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A sporulation medium for 134 Clostridium perfringens strains, including types A, B, C, D, E, and F, was devised according to Grelet's observation that sporulation occurred when cultural environment became limited in any nutritional requirement indispensable for the growth of the organism. Sporulation took place most prominently when 10% cooked-meat broth (pH 7.2) containing 3% Proteose Peptone and 1% glucose was used for the preculture and 2% Poli Peptone medium (pH 7.8) was used for the subculture medium. Sometimes, terminal spores could be observed. A correlation between sporulation and heat resistance was examined by use of C. perfringens strains isolated from samples heated at different temperatures. Almost all strains isolated from unheated samples and from those heated at lower temperatures gave rise to spores in our sporulation medium, but the spores were weakly heat-resistant, whereas strains isolated from samples heated at 100 C for 60 min were highly heat-resistant but sporulated poorly. A majority of these heat-resistant strains were non-gelatinolytic and definitely salicin-fermenting. 相似文献