摘要:

Inclusion bodies are described in recombinant E. coli cells harboring plasmid for the expression of a synthetic gene coding for human calcitonin tetramer. The inclusion bodies are visualized by electron microscopy and the protein is identified by immuno‐gold technique, using antibodies against synthetic human calcitonin. The diameter of the inclusion bodies is 1 micron on the averag

ISSN:0248-4900    

DOI:10.1111/j.1768-322X.1987.tb00562.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

To obtain specific immunological probes for studying molecular events involved in gene activation during early development of Drosophila, we have produced monoclonal antibodies directed against nuclear proteins differentially expressed in time and space during embryogenesis. Twenty‐five antibodies against nuclear antigens detected after the onset of zygotic genome transcription were obtained. These antigens have been distributed into six categories depending on their reactivity in dot‐blot, in Western‐blot and in immunofluorescence on embryo frozen section assays. Six antigens (fifth and sixth categories) are stage‐, but not tissue‐specific and are present in all nuclei of the embryo after the blastoderm stage. Ten antigens, the third and fourth categories, did not react on immunofluorescence and have not been characterized for a possible tissue specificity. Antigens of the first and second categories are stage‐ and tissue‐ specific. Two of them are of particular interest. The first (250 kd, recognized by the monoclonal antibody GB7) is preferentially expressed in nuclei of the ventral nerve cord, whereas the other (65 kd, recognized by the monoclonal antibody LA9) is located in nuclei of the gut and associat

ISSN:0248-4900    

DOI:10.1111/j.1768-322X.1987.tb00563.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

Variability in the heat shock response has been studied in D. subobscura, both in individuals from different strains at the same moment of development and in individuals belonging to the same strain at different moments of prepupal development. The heat shock response was independent of the genic background of the individuals, whereas a variability depending on the moment of development has been obtained. In relation to this variability two kinds of heat shock puffs have been found: those induced independently of the moment of development and those induced with a response dependent on it. In both cases a differential genic response that is dependent on the temperature of treatment has been detected.

ISSN:0248-4900    

DOI:10.1111/j.1768-322X.1987.tb00564.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

The nuclear matrix contains a group of residual non‐histone proteins which remain structurally organized after extensive extraction of isolated nuclei with a high salt buffer, nucleases and a non‐ionic detergent. Electron microscopic examination shows that the nuclear matrix is composed of a pore‐complex lamina, an intranuclear network and residual nucleoli. In CHO cells biochemical analyses performed by one‐dimensional SDS‐PAGE show three major nuclear matrix polypeptides with molecular weights between 60 and 70 kDa. Polyclonal antibodies produced against these polypeptides were used to determine their nuclear distribution. Using immunoblotting, these proteins were found in whole nuclei, nuclear matrix, and in the intranuclear network but not in the pore‐complex lamina. In order to determine the relationship between these structural proteins and the organization of the nucleus, the proteins were localized in situ. Ultrastructural detection was carried out by immunogold staining of thin sections of Lowicryl K4M‐embedded cells. In interphase nuclei all condensed chromatin clumps were labelled. The nucleolus and the interchromatin granules were never immunogold‐stained. During mitosis, the label was found to be associated with the chromosomes. This study shows that unlike the lamins, these 60‐70 kDa nuclear matrix proteins are associated with the condensed chromatin througho

ISSN:0248-4900    

DOI:10.1111/j.1768-322X.1987.tb00565.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

Xenopus oocytes contain a radial network of cytokeratins which seems to fragment during meiosis reinitiation (maturation). The mature egg contains only a cortical network of cytokeratins. We have looked for the presence of soluble cytokeratins in oocytes and unfertilized eggs and have found them in both cases. However, the proportion of soluble to insoluble cytokeratins is slightly higher in the egg than in the oocyte. Soluble cytokeratins incorporate 35S‐methionine at a high rate in the oocyte but to a lesser extent in the egg. This suggests that they are biosynthetic intermediates in the oocyte. In the egg, at least a fraction of the soluble cytokeratins may arise from the fragmentation of the polymer which seems to occur during the maturation process. Insoluble cytokeratins are strongly labeled with 32P both in oocytes and eggs. On the other hand only the soluble keratins of the egg incorporate 32P. Since the isoelectric point of soluble and insoluble cytokeratins is the same in oocytes and eggs, their absolute level of phosphorylation probably remains relatively constant. This suggests that: i) phosphate turnover is very slow in oocyte soluble cytokeratins, ii) phosphorylation is not a major way of changing the structural state of cytokeratins in amphibian oocytes and egg

ISSN:0248-4900    

DOI:10.1111/j.1768-322X.1987.tb00566.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

In the quail oviduct, the mature ciliated cells contain a well developed and polarized cytokeratin network which is bound to desmosomes and in close contact with the striated rootlets associated with basal bodies. In ovariectomized quail, the immature epithelial cells of oviduct present a rudimentary cytokeratin network associated with the centrioles of the diplosome (one of them forming a primary cilium) and with the short striated rootlets. The development of the cytokeratin network which occurs simultaneously with the ciliogenesis was observed by electron microscopy and immunocytochemistry (immunofluorescence and immunogold staining) using a prekeratin antiserum. During estrogen‐induced ciliogenesis, cytokeratin intermediate filaments are always found associated with the different ciliogenic structures i.e. [dense granules, deuterosomes, procentrioles and centrioles]. In ciliogenic cells, the procentrioles and centrioles seem to be associated with the intermediate filaments by their pericentriolar material. These direct contacts decrease once the centrioles/basal bodies are anchored to the plasma membrane. Simultaneously the striated rootlets develop and associate with cytokeratin. The ciliogenic cells appear as a suitable system for studying in vivo, the possible association between centrioles and intermediate filaments and its functional meanin

ISSN:0248-4900    

DOI:10.1111/j.1768-322X.1987.tb00567.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

Estramustine, a new anti‐microtubule drug, was added to the culture medium of rabbit mammary explants with lactogenic hormones. In the absence of the drug, prolactin with insulin and cortisol stimulated DNA synthesis and it induced beta‐casein and beta‐casein mRNA accumulation in the tissue. As opposed to other anti‐microtubule agents such as colchicine, estramustine was unable to prevent prolactin actions. An examination of the mammary cells by immunofluorescence revealed that the microtubule network was significantly altered under the influence of estramustine. These data indicate that the integrity of microtubules is not required for prolactin to deliver its message to the mammary cell. These data also suggest that other anti‐microtubule drugs such as colchicine which prevent prolactin action act through their binding to tubulin molecule unrelated to microtubule s

ISSN:0248-4900    

DOI:10.1111/j.1768-322X.1987.tb00568.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

The release of acetylcholine (ACh) from instantly frozen Torpedo electric organ synaptosomes in the course of stimulation is systematically associated with an increase in the number of large intramembrane particles counted on freeze‐fracture replicas. The drug cetiedil, which is a potent inhibitor of ACh release, also blocks the increase in the number of large particles. The blockage was studied either after ionophore A 23187 or Glycera neurotoxin action in the presence of calciu

ISSN:0248-4900    

DOI:10.1111/j.1768-322X.1987.tb00569.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

The human colonic epithelial cell line Cl.16E grows in culture as a polarized monolayer which differentiates at confluency into typical goblet cells secreting their mucin content into the culture medium. Polyclonal antibodies raised against these mucins were used in an ELISA to measure the amount of mucins secreted by the Cl.16E cells. Carbachol caused a transient and significant increase in mucus secretion with a maximal stimulation occurring at 30 min. A dose‐dependent effect was found with a maximal stimulation with 10‐3M carbachol. This effect was inhibited by atropine. These results indicate that the effects of carbachol are mediated by muscarinic receptors present on mucus‐secreting epithelial

ISSN:0248-4900    

DOI:10.1111/j.1768-322X.1987.tb00570.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

The enteral absorption of particles has been investigated in the dog using a colloidal drug carrier, polyalkylcyanoacrylate nanocapsules loaded with an iodized oil (Lipiodol), as a tracer for X‐ray microprobe analysis in a scanning electron microscope. Nanocapsules are spherical capsules, 100 to 200 nm in diameter, with a continuous polymeric wall surrounding a cavity which encapsulates the drug. Administered in the jejunal lumen, Lipiodol nanocapsules improved the absorption of the tracer as indicated by increased concentration of iodine in the plasma of mesenteric blood. In order to follow nanocapsules at the cellular level, all tissue compartments were preserved in a life‐like state by cryofixation and freeze‐drying of intestinal biopsies. Nanocapsules appeared in the intestinal lumen close to the mucus, then in intercellular spaces and defects of the mucosa and finally in the lamina propria and blood capillaries; in this latter compartment, the iodine content was four‐fold higher than after intra‐jejunal administration of Lipiodol emulsion. This complete phenomenon occurred only at the tip of the villi and happened within less than 60 min. We conclude that nanocapsules enhance the rate of absorption of Lipiodol and transport the drug from the intestinal lumen to the vascular compartment using a paracellular pathway. Thus they may be useful as drug carrier for oral administration of many

ISSN:0248-4900    

DOI:10.1111/j.1768-322X.1987.tb00571.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY