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991.
Continuous multiplication of rabbit tracheal epithelial cells in a defined,hormone-supplemented medium 总被引:16,自引:0,他引:16
Summary An improved Ham’s F12 nutrient medium supplemented with epidermal growth factor (EGF), insulin (INS), and transferrin (TF)
was developed for continuous proliferation and clonal growth of primary rabbit tracheal epithelial (TE) cells in culture.
The addition of small quantities of fetal bovine serum (FBS) (0.01 to 0.1%) to cultures had little measurable stimulation
on TE cell growth and plating efficiency. However, serum levels higher than 0.1% inhibited cell growth and also masked the
growth stimulating activities of EGF and INS despite an increase in cell attachment. Under this defined, hormone-supplemented
medium, and in the presence of a trace amount of serum (0.01%), 10 to 20% of the protease-dissociated TE cells attached to
the culture dish followed by at least four population doublings during 7 to 10 d of culture. Clonal growth occurred at a seeding
density of 17 cells/cm2 with a plating efficiency of 6 to 8%. Confluent primary cultures could be passaged two to four times by treatment with a
0.1% trypsin-1 mM EDTA solution and a total of 10 to 30 population doublings of in vitro life span were obtained. The epithelial nature of
cultured cells was confirmed by indirect immunofluorescent staining with antikeratin antibody as well as by transmission electron
microscopy. This study shows that using this improved hormone-supplemented medium, rabbit TE cells can be maintained in culture
for extended periods of time without the aid of a fibroblast feeder layer or explant tissue. This system could be useful for
the study of cell differentiation of tracheal epithelium. 相似文献
992.
A new agarose-acrylamide gradient slab gel electrophoresis system is described. The preparation of this new gel has been facilitated by the use of agarose with a relatively low gelation temperature. Fractionation of marker proteins and crosslinked proteins from a subcellular cytoskeletal preparation on agarose-acrylamide gradient gels is compared to that found using other acrylamide gel electrophoresis systems. 相似文献
993.
High-dose carbachol (10?3 M) has previously been shown to cause NaCl absorption in short-circuited rabbit ileum. The mechanism of this effect may be norepinephrine release induced by carbachol activation of presynaptic nicotinic receptors on adrenergic neurons. Norepinephrine then interacts with postsynaptic α-adrenergic receptors on intestinal mucosal cells to stimulate neutral NaCl absorption and inhibit electrogenic bicarbonate secretion. The present paper examines the intestinal ion transport effects of DMPP an agent which is more specific than carbachol on nicotinic cholinergic receptors. DMPP (10?5 M) caused a transient increase followed by prolonged depression of the short-circuit current, increased NaCl absorption and increased tissue conductance. This effect was antagonized by hexamethonium and phentolamine. It is concluded that nicotinic cholinergic agents stimulate norepinephrine release from adrenergic nerves and effect intestinal ion transport just as norepinephrine does. 相似文献
994.
Walter C. Kruckeberg Barry J. Sander Donna C. Sullivan 《Experimental parasitology》1981,51(3):438-443
This paper documents the maximal activities of the glycolytic enzymes in the red blood cells of normal mice and mice infected with Plasmodium berghei. There appears to be sufficient parasite-related activity of each glycolytic enzyme to support the increased glycolytic rate, i.e., increased glucose consumption, of the parasite-infected red blood cell. The relative proportions of glycolytic enzyme activities in parasite-infected red cells are different from the proportions in either normal or reticulocyte-rich blood, indicating that the increased enzyme activities associated with infected cells are not due to contaminating host red cells or reticulocytes. A comparison of maximal enzyme activities to the rate of whole cell glucose consumption indicates that different glycolytic control mechanisms are operating in the infected RBC from those in the uninfected cells. 相似文献
995.
Caroline C. Whitacre David H. Mattson Philip Y. Paterson Raymond P. Roos Donna J. Peterson Barry G. W. Arnason 《Neurochemical research》1981,6(1):87-96
Rabbits sensitized with whole nervous tissue or myelin basic protein (MBP) plus adjuvant and developing experimental allergic encephalomyelitis (EAE) were studied for the presence of oligoclonal immunoglobulin (Ig) bands in spinal fluid and serum. Samples obtained prior to sensitization and at the time of sacrifice were concentrated and subjected to agar gel electrophoresis. Of 11 rabbits receiving whole nervous tissue and developing severe clinical signs of EAE, 7 showed new oligoclonal Ig bands in spinal fluid and in serum obtained 19 days or more after sensitization. With MBP sensitization, 2 of 6 rabbits exhibited new spinal fluid bands, while all 6 rabbits studied demonstrated serum banding. The bands were identified as IgG by immunochemical studies using peroxidase-labeled antisera and byStaph. protein A absorption. The majority of animals showed no banding in presensitization samples. The finding of oligoclonal IgG in EAE reveals yet another immunologic correlation between EAE and the human demyelinating disease, multiple sclerosis. 相似文献
996.
Seedlings of Spartina alterniflora Loisel., from seed harvested from nine marshes ranging from Maine to Virginia, were grown for three seasons in plots established on two different soils in Delaware and were flooded regularly with water from two estuarine sources. Substantial differences in the time of flowering were observed. Each year plants from Maine seed flowered first and were followed by those from Connecticut and New York. Last to flower were plants from Virginia seed. The latter initiated flowering after flowering of the Maine source had been completed. These two would not cross-pollinate under this circumstance. The phenology of anthesis and number of seeds set on inflorescences enclosed in bags indicate that this species is largely open pollinated. 相似文献
997.
Characterization of an Autosomal Rudimentary-Shaped Wing Mutation in DROSOPHILA MELANOGASTER That Affects Pyrimidine Synthesis 总被引:1,自引:1,他引:0 下载免费PDF全文
A new autosomal mutation, rudimental (ral), which causes rudimentary-shaped wings in Drosophila melanogaster, has been isolated following ethyl methanesulfonate (EMS) mutagenesis. The wing phenotype of rudimental is identical to that of the X-linked rudimentary (r) mutation, which affects the first three enzymes in the pyrimidine biosynthetic pathway. The autosomal mutant maps very close to ebony (3–70.7) at 70.42 on the right arm of chromosome 3. Analysis of the enzyme activities of orotate phosphoribosyltransferase (OPRTase) and orotidylate decarboxylase (ODCase) indicates that the rala26a allele has less than wild-type activity for both enzymes. This result is discussed in light of the fact that the OPRTase and ODCase activities are part of an enzyme complex, as are the carbamyl phosphate synthetase (CPSase), aspartate transcarbamylase (ATCase) and dihydroorotase (DHOase) activities, which are encoded by the complex rudimentary locus. We suggest that rudimental is also a complex locus. 相似文献
998.
Donna Beth Willey-Courand R Scott Harris Gaetano G Galletti C A Hales Alan Fischman Jose G Venegas 《Journal of applied physiology》2002,93(3):1115-1122
Regional changes in ventilation and perfusion occurring in the early hours after smoke inhalation injury were evaluated through the use of positron emission tomography. Five lambs were imaged before and 1, 2, and 4 h after receiving 100 breaths of cotton smoke. Utilizing a recently developed model of (13)N tracer kinetics (3), we evaluated changes in ventilation, perfusion, shunt, and regional gas content in nondependent, middle, and dependent lung zones. The data demonstrated a progressive development of regional shunt in dependent (dorsal) regions in which perfusion remained the highest throughout the study. These findings, together with decreasing regional ventilation and fractional gas content in the dependent regions, correlated with decreasing arterial Pa(O(2)) values over the course of the study. A negative correlation between regional shunt fraction and regional gas content in dependent and middle regions suggests that shunt was caused by progressive alveolar derecruitment or flooding. 相似文献
999.
Brominated Biphenyls Prime Extensive Microbial Reductive Dehalogenation of Aroclor 1260 in Housatonic River Sediment 总被引:4,自引:1,他引:3 下载免费PDF全文
The upper Housatonic River and Woods Pond (Lenox, Mass.), a shallow impoundment on the river, are contaminated with polychlorinated biphenyls (PCBs), the residue of partially dechlorinated Aroclor 1260. Certain PCB congeners have the ability to activate or “prime” anaerobic microorganisms in Woods Pond sediment to reductively dehalogenate the Aroclor 1260 residue. We proposed that brominated biphenyls might have the same effect and tested the priming activities of 14 mono-, di-, and tribrominated biphenyls (350 μM) in anaerobic microcosms of sediment from Woods Pond. All of the brominated biphenyls were completely dehalogenated to biphenyl, and 13 of them primed PCB dechlorination. Measured in terms of chlorine removal and decrease in the proportion of hexa- through nonachlorobiphenyls, the microbial PCB dechlorination primed by several brominated biphenyls was nearly twice as effective as that primed by chlorinated biphenyls. Congeners containing a meta bromine primed Dechlorination Process N (flanked meta dechlorination), and congeners containing an unflanked para bromine primed Dechlorination Process P (flanked para dechlorination). Two ortho-substituted congeners, 2-bromobiphenyl and 2,6-dibromobiphenyl (2-BB and 26-BB), also primed Process N dechlorination. The most effective primers were 26-BB, 245-BB, 25-3-BB, and 25-4-BB. The microbial dechlorination primed by 26-BB converted ~75% of the hexa- through nonachlorobiphenyls to tri- and tetrachlorobiphenyls in 100 days and removed ~75% of the PCBs that are most persistent in humans. These results represent a major step toward identifying an effective method for accelerating PCB dechlorination in situ. The challenge now is to identify naturally occurring compounds that are safe and effective primers. 相似文献
1000.
Eric A. Fyrberg Christine C. Fyrberg Joseph R. Biggs Donna Saville Clifford J. Beall Andrew Ketchum 《Biochemical genetics》1998,36(7-8):271-287
We show that different Drosophila actinisoforms are not interchangeable. We sequenced the sixgenes that encode conventional Drosophilaactins and found that they specify amino acidreplacements in 27 of 376 positions. To test the significance ofthese changes we used directed mutagenesis to introduce10 such conversions, independently, into the Act88Fflight muscle-specific actin gene. We challenged these variant actins to replace the nativeprotein by transforming germline chromosomes of aDrosophila strain lacking flight muscle actin.Only one of the 10 reproducibly perturbed myofibrillarfunction, demonstrating that most isoform-specific aminoacid replacements are of minor significance. In order toestablish the consequences of multiple amino acidreplacements, we substituted portions of theDrosophila Act88F actin gene with correspondingregions of genes encoding other isoforms. Only one offive constructs tested engendered normally functioningflight muscles, and the severity of myofibrillar defects correlated with the number of replacementswithin the chimeric genes. Finally, we completelyconverted the flight muscle actin-encoding gene to onespecifying a nonmuscle isoform, a change entailing atotal of 18 amino acid replacements. Transformationof flies with this construct resulted in disruption offlight muscle structure and function. We conclude thatactin isoform sequences are not equivalent and that effects of the amino acid replacements,while minor individually, collectively confer uniqueproperties. 相似文献