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61.
62.
Comparative electron microscope investigations on sections of the lens cortex of the normal, mature rat, rabbit, monkey, and the normal calf reveal similar patterns of intracellular organization. The superficial lens fiber contains a nucleus, mitochondria, endoplasmic reticulum, dense granules, Golgi complex, and a quantity of small structures of low opacity which appear as filamentous and spherical configurations. Variations in number, distribution, and spatial arrangement of cytoplasmic elements in lens fibers are described. These changes in the pattern of cytoplasmic organization are concomitant with development of fibers and their displacement towards the center of the lens. Structural details of the various zones of the lens epithelium and the lens fibers are compared. 相似文献
63.
Alston-Mills Brenda Li Qi Chang Ottinger Mary Ann 《In vitro cellular & developmental biology. Plant》1989,25(10):934-938
Summary Production of antibodies against peptides or poorly antigenic proteins by conventional methods often requires either large
quantities of the native immunogen or some chemical modification to increase their antigenicity. In this study an in vivo
and in vitro immunization protocol has been used to generate monoclonal antibodies against the decapeptide luteinizing hormone-releasing
hormone (LHRH). Two injections of 100 μg of avian LHRH-I into BALB/c mice were given 7 d apart. Dissociated splenocytes were
collected under sterile conditions. They were incubated with 100 μg of the immunogen in 75-cm2 tissue culture flasks in thymocyte-conditioned media. After 5 to 8 d exposure to the antigen, splenocytes were fused with
SP2/O myeloma cells by polyethylene glycol. The cells were plated into 24 wells and then incubated in hypoxanthine aminopterin
and thymidine selective media. After 14 d an initial screening was done by enzyme immunoassay. The positive wells (6/24) were
expanded into 96-well plates and rescreened. Selected lines were cloned out 3 times by limiting dilution and the most positive
expanded for ascites production. The antibody was affinity purified in a protein A column. The antibody cross-reacted with
LHRH-I and II but preferentially to LHRH-I, as shown by competitive assay. A hypothalamic extract from a mature chick showed
a higher response than preparations from whole brain explants of 1- to 3-d posthatched chicks, mature quail, and mature mouse.
This work was funded by the Maryland Agricultural Experiment Station artical no. A4975, contribution no. 8019. 相似文献
64.
Ann M. Marini Masao Kozuka Robert H. Lipsky † Thaddeus S. Nowak Jr. 《Journal of neurochemistry》1990,54(5):1509-1516
Induction of the 70-kDa heat shock protein, hsp70, was evaluated in cultured cerebellar astrocytes and granule cell neurons subjected to a hyperthermic stress, using a monoclonal antibody and an oligonucleotide probe that selectively recognize stress-inducible species of hsp70-related proteins and RNAs, respectively. Immunoblots of cultures enriched in either granule cells or astrocytes, and immunocytochemical localization studies in cocultures of these cell types, demonstrated that hsp70 induction was restricted to the astrocyte population. Amino acid incorporation experiments showed little difference in the loss and recovery of overall protein synthesis activity in these two cell types following transient hyperthermic stress. RNA blot hybridizations confirmed the preferential glial induction of hsp70. In vivo immunocytochemical studies in brains of adult rats following hyperthermia were consistent with earlier observations that suggested a primarily glial and vascular localization of the heat shock response in most brain regions, although the intense immunoreactivity in the cerebellar granule cell layer suggests that there is induction of hsp70 in these neurons under in vivo conditions. These results suggest the potential value of such defined cell cultures in identifying mechanisms responsible for differences in the heat shock response of various cell types in vitro, and in revealing factors that may account for the apparent absence of the stress response in cultured cerebellar granule cell neurons. 相似文献
65.
Ann Curtis F. Millan Susan Holloway Moira Mennie Aileen Crosbie J. A. Raeburn D. J. H. Brock 《Human genetics》1989,81(2):188-190
Summary Presymptomatic testing for Huntington's disease (HD) is possible through the use of restriction fragment length polymorphisms (RFLPs) at the closely linked D4S10 locus. Recombination between the HD and D4S10 loci will occur in 4%–5% of meioses, and is a well-recognised complication of predictive testing. Recombination between RFLPs within the D4S10 locus is a rare event and can usually be ignored. We report a case where such an intra-locus recombination frustrated attempts to predict the chance of a high-risk individual inheriting the HD gene. 相似文献
66.
67.
Studies demonstrating differences in chloroplast structure and biochemistry have been used to formulate hypotheses concerning the origin of algal plastids. Genetic and biochemical experiments indicate that significant variation occurs in ribulose-1,5-bisphosphate carboxylase (Rubisco) when supertaxa of eukaryotic algae are compared. These differences include variations in the organelle location of the genes and their arrangement, mechanism of Rubisco synthesis, polypeptide immunological reactivity and sequence, as well as efficacy of substrate (ribulose bisphosphate and CO2) binding and inhibitor (6-phosphogluconate) action. The structure-function relationships observed among chromophytic, rhodophytic, chlorophytic and prokaryotic Rubisco demonstrate that: (a) similarities among chromophytic and rhodophytic Rubisco exist in substrate/inhibitor binding and polypeptide sequence, (b) characteristic differences in enzyme kinetics and subunit polypeptide structure occur among chlorophytes, prokaryotes and chromophytes/rhodophytes, and (c) there is structural variability among chlorophytic plant small subunit polypeptides, in contrast to the conservation of this polypeptide in chromophytes and rhodophytes. Taxa-specific differences among algal Rubisco enzymes most likely reflect the evolutionary history of the plastid, the functional requirements of each polypeptide, and the consequences of encoding the large and small subunit genes in the same or different organelles. 相似文献
68.
Chromosomal polymorphism regarding number of NOR sites in the cyprinid fish Chondrostoma lusitanicum was examined using C-banding, silver-staining (Ag), and fluorescent staining with chromomycin A3 (CMA3). The analysis of heterochromatic regions allowed a more precise identification of the centromeric regions and the proposal of a revised haploid chromosome formula (7M: 15S: 3A). We describe variability in the number of NOR regions per genome, number of active NOR sites per cell, and relative size of individual NORs. Individuals expressed two or four NOR-bearing chromosomes. Polymorphism was detected in all the populations studied and sex-related differences were not found. The observed chromosomal NOR phenotypes suggest the occurrence of structural rearrangements during the evolutionary process of this diploid leuciscine cyprinid. 相似文献
69.
Figueiredo A. Cristina Almendra M. João Barroso José G. Scheffer Johannes J. C. 《Biotechnology letters》1996,18(8):863-868
The transformation capacity of Achillea millefolium L. ssp. millefolium (yarrow) cell suspension cultures was investigated using geraniol (50mg/l) and borneol, menthol, thymol and farnesols (25mg/l) as substrates. Apart from converting these substrates into several biotransformation products, the cell suspension cultures were also able to glycosylate both the substrates and the biotransformation products. aa]Key Words bb]Achillea millefolium L. ssp. millefolium bb]Yarrow bb]Compositae bb]Biotransformation bb]Glycosylation bb]Geraniol bb]Borneol bb]Menthol bb]Thymol bb]Farnesols 相似文献
70.
Robert N. Fontaine Ruanna E. Gossett Friedhelm Schroeder Barbara A. O'Toole Thomas Doetschman Ann B. Kier 《Molecular and cellular biochemistry》1996,159(2):149-153
The effect of transforming growth factor beta-1 (TGF1) expression on fatty acid binding proteins was examined in control and two strains of gene targeted TGF1-deficient mice. Homozygous TGF1-deficient 129 × CF-1, expressing multifocal inflammatory syndrome, had 25% less liver fatty acid binding protein (L-FABP) when compared to control mice. The decrease in L-FABP expression was not due to multifocal inflammatory syndrome since homozygous TGF1-deficient/immunodeficient C3H mice on a SLID background had 36% lower liver L-FABP than controls. This effect was developmentally related and specific to liver, but not the proximal intestine, where L-FABP is also expressed. Finally, the proximal intestine also expresses intestinal-FABP (1-FABP) which decreased 3-fold in the TGF1-deficient/immunodeficient C3H mice only. Thus, TGF1 appears to regulate the expression of L-FABP and I-FABP in the liver and the proximal intestine, respectively.Abbreviations L-FABP
liver fatty acid binding protein
- I-FABP
intestinal fatty acid binding protein
- TGF1
transforming growth factor beta-1
- TNF-
tumor necrosis factor-
- MIP-
macrophage inflammatory protein-
- PMSF
phenylmethyl sulfonyl fluoride
- PBS
phosphate buffered saline 相似文献