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1.
Total polyadenylated RNA from ripening or germinating Ricinus communis L. endosperm was translated in rabbit reticulocyte lysate in the absence or presence of canine pancreatic microsomes. The products were immunoprecipitated using antibodies raised againts Triton X-114-extracted integral membrane proteins of protein bodies or glyoxysomes. While the proteins of proteinbody membranes were found to insert co-translationally into added microsomes, this was not observed in the case of glyoxysomal proteins. This observation was confirmed using antibodies raised against a purified glyoxysome membrane protein, alkaline lipase. These results indicate that different routes exist for the insertion of membrane proteins into the two organelles. In both cases membrane-protein insertion does not appear to be accompanied by proteolytic processing.Abbreviations anti-PB
antiserum to integral protein-body membrane proteins
- anti-G
antiserum to integral glyoxysomal membrane proteins
- anti-L
antiserum to alkaline lipase
- ER
endoplasmic reticulum
- Mr
relative molecular mass
- mRNA
poly(A)-rich messenger RNA
- PAGE
polyacrylamide gel electrophoresis
- poly(A)
polyadenylic acid
- SDS
sodium dodecyl sulphate 相似文献
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Twice daily injections of purified ovine and human FSH were used to investigate the control of ovarian follicle development in hypogonadotrophic hypogonadal (hpg) mice. Treatment for 5 days with doses greater than 3 micrograms resulted in a significant increase in the total number of growing follicles and the development of antral follicles. This was associated with increases in uterine weights and vaginal opening, indicating that steroidogenesis had also been stimulated. Further studies of the effects of combined injections of FSH and LH, linked with morphological analysis of ovarian interstitial cells, suggested that any contribution of background or contaminating LH to the effects of the FSH injections was minimal. It therefore appears that, in mice, FSH alone is capable of stimulating an increase in the initiation of follicle growth, of triggering the development of antral follicles, and supporting ovarian steroidogenesis. 相似文献
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E M Rosen I D Goldberg H M Shapiro L C Zoller K V Myrick S E Levenson P A Halpin 《Journal of cellular physiology》1985,125(3):512-520
The smooth muscle cell population in major arteries of humans and experimental animals is heterogeneous with regard to cellular DNA content. A proportion of cells has polyploid DNA content and this proportion increases with normal aging and with hypertension. We have isolated pure populations of rat aortic smooth muscle cells containing 2C, 4C, and 8C DNA content by cloning of cultures of cells previously subjected to flow cytometric cell sorting. Karyologic analysis of these clonal populations revealed them to be pure diploid, tetraploid, and octaploid populations, respectively, containing 2N (= 42), 4N, and 8N chromosomes. Cell attachment area and nuclear size appeared to increase with the level of ploidy. Studies of the proliferative characteristics of the cells revealed that the growth rate and ultimate cell densities achieved decreased as the ploidy level increased. The intrinsic cellular radiosensitivity of these clones did not vary with ploidy. Increased smooth muscle cell ploidy is, therefore, associated with a decreased rate of proliferation. The emergence of smooth muscle cells with polyploid DNA content under normal and pathologic conditions is probably due to mitotic polyploidization without net cell proliferation and may be related to the need for expression of differentiated functions. 相似文献
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Purification and characterization of cinnamyl alcohol dehydrogenase from tobacco stems 总被引:4,自引:2,他引:2 下载免费PDF全文
Cinnamyl alcohol dehydrogenase (CAD) is an enzyme involved in lignin biosynthesis. In this paper, we report the purification of CAD to homogeneity from tobacco (Nicotiana tabacum) stems. The enzyme is low in abundance, comprising approximately 0.05% of total soluble cell protein. A simple and efficient purification procedure for CAD was developed. It employs three chromatography steps, including two affinity matrices, Blue Sepharose and 2′5′ ADP-Sepharose. The purified enzyme has a specific cofactor requirement for NADP and has high affinity for coniferyl alcohol (Km = 12 micromolar) and coniferaldehyde (Km = 0.3 micromolar). Two different sized polypeptide subunits of 42.5 and 44 kilodaltons were identified and separated by reverse-phase HPLC. Peptide mapping and amino acid composition analysis of the polypeptides showed that they are closely related, although not identical. 相似文献
6.
Zuleyma Tang Halpin 《Oecologia》1981,51(3):419-425
Summary The demographic and ecological characteristics of island populations of small mammals have received increasing attention in recent years, but few studies have compared the behavioral characteristics of island populations with those of mainland populations. Behavior is considered an important variable because it is believed by many to be a crucial factor affecting the population dynamics and demography of natural populations. In particular, among many species of rodents, the social behavior of adults towards juveniles is cited as an important factor influencing dispersal patterns and population regulation. The present study compares social interactions between adults and juveniles of island and mainland populations of the deermouse Peromyscus maniculatus, and attempts to relate differences in behavior to the demographic differences between the two populations. Adult mice were trapped on the mainland of British Columbia and on one of the Gulf Islands off the British Columbia coast, and allowed to breed in the laboratory. Male and female juveniles from both populations were then tested with their own parents and with unrelated male and female adults. The results demonstrate that island adults show almost no aggression towards either own or unrelated young. Mainland adults likewise show little aggression towards their own young, but a proportion of the population, consisting of both male and female adults, shows severe aggression towards unrelated juveniles of both sexes. These results suggest four major conclusions: 1) behavior may be the mechanism responsible for the demographic differences reported for these island and mainland populations; 2) female aggression may be a more important factor in deermouse population dynamics than has been previously recognized; 3) since parents show little aggression towards their own young, adult aggression may be a significant factor in juvenile mortality and emigration only after juveniles have initiated dispersal away from their natal sites; and 4) adult aggression controls the number of both male and female juveniles which are recruited into the population. 相似文献
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Kazima Saira Xudong Lin Jay V. DePasse Rebecca Halpin Alan Twaddle Timothy Stockwell Brian Angus Alessandro Cozzi-Lepri Marina Delfino Vivien Dugan Dominic E. Dwyer Matthew Freiberg Andrzej Horban Marcelo Losso Ruth Lynfield Deborah N. Wentworth Edward C. Holmes Richard Davey David E. Wentworth Elodie Ghedin 《Journal of virology》2013,87(14):8064-8074
Influenza virus defective interfering (DI) particles are naturally occurring noninfectious virions typically generated during in vitro serial passages in cell culture of the virus at a high multiplicity of infection. DI particles are recognized for the role they play in inhibiting viral replication and for the impact they have on the production of infectious virions. To date, influenza virus DI particles have been reported primarily as a phenomenon of cell culture and in experimentally infected embryonated chicken eggs. They have also been isolated from a respiratory infection of chickens. Using a sequencing approach, we characterize several subgenomic viral RNAs from human nasopharyngeal specimens infected with the influenza A(H1N1)pdm09 virus. The distribution of these in vivo-derived DI-like RNAs was similar to that of in vitro DIs, with the majority of the defective RNAs generated from the PB2 (segment 1) of the polymerase complex, followed by PB1 and PA. The lengths of the in vivo-derived DI-like segments also are similar to those of known in vitro DIs, and the in vivo-derived DI-like segments share internal deletions of the same segments. The presence of identical DI-like RNAs in patients linked by direct contact is compatible with transmission between them. The functional role of DI-like RNAs in natural infections remains to be established. 相似文献