摘要:

Summary—Epithelial glands were isolated from guinea‐pig endometrium. In order to reduce the requirement for a serum supplement and the contamination by non epithelial cells in primary culture, various coatings of the culture dishes were tested using serumfree Ham's F12 containing defined chemicals including 17β‐estradiol. while epithelial glands seeded on culture dishes coated with Matrigel, a basement membrane matrix‐failed to spread, they formed on poly‐d‐lysine plus serum‐coated dishes, a subconfluent monolayer (5–7 days) enriched in cytokeratin‐immunostained cells (78%). Cells from subconfluent primary cultures, obtained on poly‐d‐lysine plus serum‐coated dishes in serum‐free hormonally defined medium, were passaged on Matrigel‐coated dishes in serum‐free hormonally defined medium. These subcultures contained, at confluence (4–5 days), a high percentage (>95%) of cytokeratin‐immunostained cells. These monolayers consisted of well‐differentiated cells which exhibited ultrastructural features characteristics of endometrial epithelial cells. Moreover, these confluent cells contained 50% immunostained nuclei for progesterone receptors. Progesterone receptor amounts decreased in confluent subcultures treated with progesterone and became undectable after longterm treatment, suggesting responsiveness of these cells to progesterone. This culture system provides a well‐defined model for the study of protein synthesis and secretion by endometrial

ISSN:0248-4900    

DOI:10.1016/0248-4900(91)90268-R

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Summary—The influence of culture duration on some characteristics of hepatocyte subcellular membranes involved in endocytosis was investigated. Activity of enzymes located in plasma membrane, Golgi apparatus and lysosomes increases with time. These modifications are accompanied with several changes in sedimentation properties of these organelles. Endocytosis of [14C]sucrose and [14C]surcose‐LDL is not affected by culture age. On the contrary, [14C]sucrose‐ASF endocytosis strongly decreases in these conditions. These modifications are delayed to some extent by lowering the temperature. Addition to the culture medium of 3‐methyladenine (an inhibitor of autophagy), sodium butyrate, dimethylsulfoxide, phenobarbital or nicotanamide does not prevent the decrease of ASF endocytosis caused by culture duration. These results indicate that one must be cautions when extrapolating to liverin vitro, observations on endocytosis obtained with primary culture of hepa

ISSN:0248-4900    

DOI:10.1016/0248-4900(91)90269-S

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Summary—The effect of extensive differentiation on the synthesis and accumulation of protein 4.1 were studied on Friend erythroleukemia grown in suspension and on fibronectin coated dishes. Whole membranes of Friend erythroleukemia cells (FELC) contained a protein 4.1a and 4.1b doublet ofMr76 and 74 kDa and two minor bands ofMr105 and 43 Da that cross‐reacted with anti‐human protein 4.1 IgG. These proteins were present even in uninduced cells. the synthesis of protein 4.1 was maximal after 4 days of induction in both suspension culture and in fibronectin‐coated dishes whereas the protein 4.1 continued to accumulate until the seventh day. More protein 4.1 accumulated in cells grown on fibronectin‐coated dishes, at each stage of differentiation, than in cells grown in suspension. The protein 4.1a/4.1b ratio changed during differentiation. The amounts of protein 4.1b increased progressively after induction until the protein 4.1a/4.1b ratio was similar to that of mouse mature erythrocyte. The protein 4.1a/4.1b ratio appears to be an internal marker of erythroid differ

ISSN:0248-4900    

DOI:10.1016/0248-4900(91)90270-W

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Summary—In the present study an attempt was made to localize cytochemically ATPase activity in the epidermis ofPelobates syriacusduring its metamorphic cycle. In the epidermis of the legless tadpole, evidence for ATPase activity was confined intracellularly in two cell types: on the membranes of vesicles in the vesicle cells, and in the ER and Golgi inside the granular cell. This state continued throughout most of the tadpole life during the 2‐ and 4‐limbed stages. This is possibly an indication for either Ca2+‐ or Mg2+‐ATPases. Only in later stages, preceding metamorphic climax, did Na+‐K+‐ATPase activity shift to the baso‐lateral cell membranes bordering with the intercellular spaces. This continued after metamorphic climax in the juvenile toadlets, diminishing later in

ISSN:0248-4900    

DOI:10.1016/0248-4900(91)90271-N

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Summary—A cell‐to‐substratum adhesion assay is developed to study the adhesion of sea‐urchin embryonic cells to coated substrata. The involvement in this process of both carbohydrate and protein molecules is reported. Concanavalin A (Con A) increases the attachment of cells to the substratum in a dose‐dependent manner and this effect is completely abolished when the incubation is carried out in the presence of the specific monocarbohydrate Con A‐inhibitor, α‐methyl‐d‐mannoside. A Con A‐mediated enhancement of cell‐to‐substratum adhesion was also detected on cells deprived of toposome, a glycoprotein complex responsible for cell‐to‐cell adhesion. The involvement of other molecules as well as toposome in the process of cell‐to‐substratum adhesion is also investigated. Results of thesein vitroexperiments indicate that all the molecules tested contribute to the proces

ISSN:0248-4900    

DOI:10.1016/0248-4900(91)90272-O

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Summary—The fluorescent hydrophobic plasma membrane probe, trimethylamino‐diphenylhexatriene (TMA‐DPH) was previously shown to follow the plasma membrane throughout its internalization and recycling process and thus to behave as a marker for endo‐ and exocytosis in living cell systems. In this paper, we made use of these properties to investigate membrane fluidity effects associated with endocytosis in L929 cells. For that purpose we performed TMA‐DPH fluorescence anisotrophy measurements which showed that endocytosis starts from particularly rigid regions of the plasma membrane (probably coated pits). The fluorescence anisotropy then continuously decreases to a lower limit corresponding to the membrane fluidity of the probe in the lysosomial membrane. Strikingly, the value of this limit is identical to the average anisotropy value in the peripheral membrane, which suggests that lysosomes and plasma membrane may have a similar phospholipidic composition and a possible comm

ISSN:0248-4900    

DOI:10.1016/0248-4900(91)90273-P

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Summary—Three‐dimensional analysis demonstrated the presence of cytoplasmic vela extending from exocrine cells into the space between endocrine cells and basal lamina in the gastrointestinal epithelium of the rabbit; these structures were also observed in various other mammals. The following techniques were used to determine the morphologic characteristics of these vela and to study their significance: preparation of semiserial thin sections, three‐dimensional reconstruction in plexiglass and lanthanum staining of pericellular spaces. It was found that these fine vela, devoid of major differentiated cell‐constituents, sometimes form a pseudocircular crown at the base of endocrine cells. If the zone of basal apposition of the plasma membrane is referred to as ZBA and the zones of lateral apposition as ZLA, the presence of this velum makes it possible to distinguish a zone of immediate apposition without interposition (ZIA) and a mediate zone of apposition with interposition (ZMA) within the ZBA. Exocrine cell processes can also penetrate within endocrine cells in invaginations, and the depth of these invaginations can be demonstrated by lanthanum staining. Adjacent to the membrane zones defined above, other cytoplasmic microdomains‐M(ZLA) and M(ZBA), as well as M(ZIA) and M(ZMA) of different morphofunctional significance may also be

ISSN:0248-4900    

DOI:10.1016/0248-4900(91)90274-Q

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Summary—Polyclonal antibodies directed against α,l‐1.2‐arabinofuranosyl poly‐β,d‐1.4‐xylopyranosyl (degree of polymerization 130) have been raised from rabbits. The immunogold labelling in transmission electron microscopy (TEM) evidenced the arabinoxylans of the plant cell walls. Comparison between the stems of normal and mutant bm3 maize demonstrated a greater accessibility of arabinoxylans in the walls of the mutant maize. The method, specific and swift, allows us to specify the repartition in the different parts of the stem: sclerenchyma, fiber

ISSN:0248-4900    

DOI:10.1016/0248-4900(91)90275-R

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Summary—Liver peroxisomes of two anuran amphibian species,Rana esculentaandXenopus laevis, were studied in untreated and in clofibrate‐treated adults by means of complementary technical approaches,ie, ultrastructural cytochemistry, cell fractionation and marker enzyme activity assays. In untreated adults, hepatic peroxisomes were found to be very scarce inXenopuswhen compared toRana. Activities of catalase,d‐amino acid oxidase and of the three first enzymes of the peroxisomal β‐oxidation system were detected in the light mitochondrial fractions enriched in peroxisomes and prepared from livers of both species. Administration of clofibrate at a daily dose level of 60 mg (Rana) and 90 mg (Xenopus) during ten days induced a drastic peroxisome proliferation inRanahepatocytes but had no visible effect on the hepatic peroxisomal population ofXenopus. The catalase activity and the peroxisomal β‐oxidation system of liver cells were enhanced inRanaas well as inXenopus. The hepaticd‐amino acid oxidase specific activity was increased inRanawhereas it remained rather constant inXenopus. Taking advantage of the behaviors ofRanaandXenopushepatic peroxisomes, the molecular mechanisms of clofibrate induction are now investigated in the target liver cells of the two amph

ISSN:0248-4900    

DOI:10.1016/0248-4900(91)90276-S

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Summary—In addition to the known Sertoli‐cell processes, processes of the mouse spermatid's cytoplasm are found to invaginate neighbouring spermatids. Surrounded by the adjacent Sertoli process, the spermatid processes form a “spermatid‐Sertoli cell process”. They are observed between spermatids at the same step or at different steps of their development and degenerate mostly at step 13 to 15 of spermiogenesis. Whether these structures are related to either spermatid exchanges or connections or participate to cytoplasm elimination is

ISSN:0248-4900    

DOI:10.1016/0248-4900(91)90277-T

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY