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11.
The expression of proteins that play a role in neuronal differentiation was examined in central nervous system (CNS) micromass embryo cell cultures and compared to expression at comparable developmental stages in vivo. The protein product of the src proto-oncogene (pp60c-src) has been postulated to have a specific role in development because, although it is expressed in many tissues, marked increases in amount and activity of pp60c-src
occur in neurons at the time of differentiation. Another protein of interest, high molecular weight neurofilament (NF) protein, is found in differentiated neurons. In the present study, changes over time in the expression of these two proteins in vitro and in vivo were examined. In the micromass cell cultures, primary cells from day 12 rat embryo CNS are plated at high density and differentiate into neurons during five days in culture. Tissues from embryos grown in vivo were assessed at 12 and 17 days post-coitum. Proteins were quantified by PAGE separation of equal amounts of total protein followed by transfer to membranes, immunoblotting, and densitometric scanning of blots. Increases in the amount of both proteins with neuronal differentiation was shown. Protein kinase activity of immunoprecipitated pp60c-src
also increased in cell cultures and in embryos. Similarity in patterns of expression between in vitro and in vivo tissue samples provides further evidence that the cultures closely simulate in vivo differentiation and are a useful system for examining expression of developmental genes in vitro.Abbreviations BCIP
5-bromo-4-chloro-3-indolylphosphate p-toluidine salt
- CNS
central nervous system
- DPBS
Dulbecco's phosphate-buffered saline
- GAM-AP
goat anti-mouse IgG alkaline phosphatase conjugate
- LB
limb bud
- NF
high molecular weight neurofilament protein
- NBT
nitroblue tetrazolium chloride
- SDS-PAGE
polyacrylamide gel electrophoresis
- PVDF
polyvinylidene difluoride
- RIPA
radioimmunoprecipitation
- TBS
Tris-buffered saline
- TTBS
TBS with 0.05% Tween-20
Presented in part at the 1989 and 1990 Teratology Society Meetings and the 1990 Society of Toxicology Meetings. 相似文献
12.
Elaine F. Smith Andrew V. Roberts John Mottley Susan Denness 《Plant Cell, Tissue and Organ Culture》1991,27(3):309-313
Plantlets of Dendranthema grandiflora Pennine Reel were grown from nodal sections on Sorbarods saturated with liquid medium containing 0–3 mg 1–1 of various growth retardants. After 4 weeks they were transferred to compost and maintained at a relative humidity of 42% at 27.5°C. Wilting was assessed over a period of 3 h. Plantlets treated with paclobutrazol, flurprimidol, triapenthenol, chlorphonium chloride, uniconazol and ancymidol showed dose-related reductions in wilting up to a concentration of 3 mg 1–1. Responses to tetcyclacis and mepiquat chloride were weaker, and no responses to chlormequat chloride, BTS 44584 or diaminozide could be detected. These observations are compatible with an hypothesis that resistance to wilting derives from inhibited synthesis of gibberellins. 相似文献
13.
Jean F. Emly Wendy A. Ratcliffe Elaine Green Sarah J. Bowden David A. Heath Ann Blight Susan Hughes John G. Ratcliffe 《生物化学与生物物理学报:疾病的分子基础》1992,1180(1):58-64
The molecular forms of parathyroid hormone-related protein (PTHRP) in conditioned media from the BEN human lung cancer cell line, rat parathyroid cells (PT-r) and human keratinocytes were studied by gel-filtraton chromatography with assay of PTHRP by immunoassays and bioassay. Immunoreactivity (1–86 and 1–34) and bioactivity (1–34) in conditioned media eluted as a coincident major peak (approx. molecular mass 19–22 kDa) and there was evidence of amino-terminal species in the molecular mass range 10–16 kDa in BEN and keratinocyte media. Western blotting of PTHRP affinity purified by monoclonal antibodies directed at regions 1–34 or 37–67, identified a major species in all cell cytosols and media with an apparent molecular mass of 24–25 kDa, consistently slighty larger than recombinant PTHRP(1–141) (mobility of 21 kDa) which may represent an intact or native form of PTHRP. Additional amino-terminal species were identified in medium from keratinocytes (16 and 7 kDa), BEN cells (18 and 14 kDa) and PT-R cells (17 kDa), suggesting that processing occurs at the C-terminus and within the mid-region to form a range of amino-terminal fragments. 相似文献
14.
15.
C Toniolo G M Bonora A Bavoso E Benedetti B di Blasio V Pavone C Pedone 《Journal of biomolecular structure & dynamics》1985,3(3):585-598
The infrared absorption and 1H nuclear magnetic resonance analyses of chloroform solutions of the terminally-blocked segment corresponding to the 2-9 sequence of emerimicins III and IV, -(Aib)3-L-Val-Gly-L-Leu-(Aib)2-, are consistent with the presence of a 3(10)-helical structure of high thermal stability. The crystal structure of the octapeptide, obtained by X-ray diffraction indicates the formation of a right-handed 3(10)-helix, stabilized by six consecutive intramolecular N-H....O:C H-bonds, slightly distorted at the level of the L-Leu residue. 相似文献
16.
C. Michael Bowman Elaine M. Berger Elaine N. Butler Karen M. Toth John E. Repine 《In vitro cellular & developmental biology. Plant》1985,21(3):140-142
Summary Zwitterion buffers are often used to modulate the pH of cell culture medium but their effect on cultured cells is controversial.
We found that addition of 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) caused superoxide dismutase (SOD) inhibitable
increases in nitroblue tetrazolium dye reduction and SOD and catalase inhibitable decreases in the growth of cultured bovine
pulmonary artery endothelial cells. The findings suggest that HEPES stimulates endothelial cells to make toxic oxygen metabolites
that contribute to decreased cell growth.
This work was supported in part by the National Institutes of Health, Colorado and American Lung Associations, Colorado and
American Heart Associations, the Council for Tobacco Research, and the Kroc, Hill, Swan and Kleberg Foundations. Dr. Bowman
is a Clinician Scientist Awardee of the American Heart Association. 相似文献
17.
David S. Gullion T. Elaine Adamson Malcolm S. M. Watts 《The Western journal of medicine》1983,138(4):582-588
The Professional Competence Assurance Program (PROCAP) is an individualized educational program that examines physicians'' performance in ambulatory practice. It uses medical record review to identify deficiencies in the care process that guides development of the educational intervention. Medical care is reassessed one year later. This program was used with 51 private practitioners to assess the care of 1,229 hypertensive patients. The educational program included a computer printout comparing one physician''s performance with that of peers, readings targeted to management problems, and a conference call or group seminar with an expert stressing issues relevant to each physician''s performance. Postintervention assessment showed that physicians prescribed beta-blockers (P<.01) and vasodilators (P<.01) more often. Improvement (P<.05) occurred in the control of diastolic blood pressure (≤90 mm of mercury) and in several other criteria. These results show that well-designed, individualized continuing medical education addressing specific deficiencies can change physicians'' performance and patients'' intermediate outcome. 相似文献
18.
19.
Previously existing methods for determining the pH limits for the growth of microorganisms have involved (1), the setting up of individual cultures, each having a specific pH; (2), the pH gradient plate technique devised by Sacks (1956) in which a continuous pH gradient is established in a Petri dish by means of a buffer system; and (3), the pH gradient plate technique of Zak (unpublished), in which a continuous pH gradient is established by means of an electric current. The discontinuous pH gradient technique described here provides a convenient method of determining the maximum and minimum pH at which a microorganism can grow. The technique can be used aerobically or anaerobically, and has a precision of about ± 0.1 pH unit. Data are given for several yeasts and forSerratia marcescens. In all cases, the organisms tested continued to metabolize at pH values beyond those representing the limits for growth, sometimes by as much as 0.5 pH unit. The results suggest that pH limits are unsuitable criteria in microbial classification. 相似文献