摘要:

Summary—InPleurodeles waltl, progeny resulting from a cross between 2 individuals of the Z/W sexual genotype include 25% of W/W individuals, while those issued from crossing a Z/W neomale with a W/W thelygenous female include 50% of W/W individuals. W/W individuals can be identified through the peptidase‐1 zymogram since, inP. waltl, this enzyme is controlled by codominant alleles which are linked to the sex chromosomes. In such progeny, we discovered 2 mutant phenotypes affecting larval and postmetamorphic skin pigmentation in W/W individuals. These phenotypes are described herein. The study of their inheritance in several offspring provides evidence that they are controlled by 2 distinct genes, the recessive mutant alleles of which are linked to the W sex chromosome; moreover, in thelygenous W/W females, the differential segment does not prevent the occurrence of meiotic recombinations between W sex chromosomes. Mutant skin pigmentary phenotypes are easily identified and constitute a tool for rapid, efficient selection of individuals of the W/W sexual genot

ISSN:0248-4900    

DOI:10.1111/j.1768-322X.1989.tb03004.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Summary—Several repeated DNA sequences were isolated from a partial genomic DNA library of the newtPleurodeles waltl. These repeated DNA elements are dispersed over the 12P. waltlbivalents, and some of them are transcribed in the oocyte. We describe the localization of label followingin situhybridization to nascent RNA attached to the lateral loops of lampbrush chromosomes. Variations in the number and the location of labelled loops were constantly found for several of the probes. The results are discussed in view of the “cotranscription model” of RNA synthesis on lampbrush chromosomes. We speculate on the possible origins of variation in transcription on lampbrush

ISSN:0248-4900    

DOI:10.1111/j.1768-322X.1989.tb03005.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Summary—The oocyte nucleus ofPleurodeles waltlcontains a major 185‐kDa protein analog ofXenopusN1N2. Rabbit antibodies were raised against the 185‐kDa protein. Affinity‐purified antibody directed against the acid part (pI 4.7) of the protein was prepared using antigens separated by two‐dimensional electrophoresis. Specificity of the antibody was controlled on two‐dimensional gels of nuclear proteins. It was shown that the 185‐kDa protein was separated into 2 forms: an acid form of pI 4.7–5.3, and a base form of pI 7. Peptide maps of the 2 spots revealed that they were closely related. The antibody was tested on: a) spread nuclear content, b) on sections of embryonic stages from stage 2 to stage 34, and c) the sections of adult tissies. The 185‐kDa protein appeared to be associated with the RNP matrix of a particular type of lampbrush chromosome loop, the granular loop. This protein was present in the nuclei of all embryonic cells. In adult tissues, it was present only in the nuclei of cells which presented high mitotic activity. These results confirm that, like N1N2, the 185‐kDa protein interacts with the constitution of chromatin; furthermore, they provide evidence for the role of this protein in trans

ISSN:0248-4900    

DOI:10.1111/j.1768-322X.1989.tb03006.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Summary—Nucleolin, a phosphorylated nucleolar protein, of 100 kDa selectively stained with bismuth tartrate and silver nitrate, is implicated in the transcription and maturation of pre‐ribosomal RNA. Nucleolin also fulfills a structural function in nucleolar organization. Using immunocytochemistry the action of 5–6‐dichloro‐1‐β‐D‐ribofuranosylbenzimidazole (DRB), an inhibitor of hn/RNA synthesis known to modify the organization of the nucleolus, was studied for its effects on the distribution and the amount of nucleolin present. After DRB treatment, the morphology of the nucleolus was rapidly disturbed, but the distribution of the nucleolin remained unchanged: the dense fibrillar and the granular components were always positively immunostained. Thirty min after incubation with the drug, a strong increase of the amount of nucleolin occurred. Prolonged treatment led to a marked loss of label. Silver and bismuth staining showed that DRB does not seem to significantly affect the phosphorylat

ISSN:0248-4900    

DOI:10.1111/j.1768-322X.1989.tb03007.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Summary—Afterin vitroincubation ofXenopusoocytes with vitellogenin (VTG)‐gold conjugate, the gold particles are distributed on the whole plasma membrane. Their concentration in coated pits still occurs at 0°C. At +20°C the label quickly (30 sec) appears in multi‐vesicular endosomes (MVE) which segregate together with primary endocytic vesicles into distinct clusters below the plasma membrane. From this step up to crystallization of the yolk platelets, the gold particles stay in the same compartment. During 5.5 h the label progressively increases along the MVE membrane, first (1.5 h) by fusion of primary endocytic vesicles with consecutively enlarging endosomes, then (4 h) by decreasing of the MVE membrane. As concerns the yolk platelet formation, concentration of primordial yolk platelets (PYP) occurs at 5.5 h from the incubation onset, the labeling of preexisting yolk platelets starts at 7 h, while crystallization of PYP begins only after 12–13 h.Our results indicate that VTG receptors are not preclustered in coated pits and their lateral translation is not inhibited at 0°C. The yolk protein processing takes place within one compartment only. The VTG condensation begins with a long concentration phase of receptor‐VTG complexes still integrated in the endosome membrane. It occurs in MVE by: i) a repeated fusion of primary endocytic vesicles; ii) removing part of the endosome membrane by internal vesiculation. Fusion between endosomes occurs only after VTG has dissociated from its receptors and VTG dissociates only when when the density of the VTG‐receptor complexes in the endosome membrane is sufficient. Crystallization begins after a 7–8 h delay.The endosome migration into the oocyte is also controlled by the binding of VTG to its receptors.Our results also demonstrate that binding of VTG colloidal gold modifies neither the vitellogenic pathway nor the duration of the vitellogenin internalization. However when vitellogenin is bound to colloidal gold, dissociation of ligand‐receptor complexes is delayed because the amount of ligand in the incubation medium

ISSN:0248-4900    

DOI:10.1111/j.1768-322X.1989.tb03008.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Summary—In many systems transfer between the endoplasmic reticulum and the Golgi apparatus is blocked at temperatures below 16°C. In virus‐infected cells in culture, a special membrane compartment is seen to accumulate. Our studies with rat liver show a similar response to temperature bothin situwith slices andin vitrowith isolated transitional endoplasmic relticulum fractions. With isolated transitional endoplasmic reticulum fractions, when incubated in the presence of nucleoside triphosphate and a cytosol fraction, temperature dependent formation of vesicles occurred with a Q10of −2 but was apparent only at temperatures greater than 12°C. A similar response was seenin situat 12°C and 16°C where fusion of transition vesicles withcisGolgi apparatus, but not their formation, was blocked and transition vesicles accumulated in large numbers. At 18°C and below and especially at 8°C and 12°C, the cells responded by accumulating smooth tubular transitional membranes near the cis Golgi apparatus face. With cells and tissue slices at 20°C neither transition vesicles nor the smooth tubular elements accumulated. Those transition vesicles which formed at 37°C were of a greater diameter than those formed at 4°C bothin situandin vitro. The findings show parallel responses between the temperature dependency of transition vesicle formationin vitroandin situand suggest that a subpopulation of the transitional endoplasmic reticulum may be morphologically and functionally homologous to the 16°C compartment observed in virally‐infected cell lines grown a

ISSN:0248-4900    

DOI:10.1111/j.1768-322X.1989.tb03009.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Summary—In rat parotid glands, the involvement of the microfilament system in the cellular signal transmission mechanism was tested by measuring the effect of cytochalasin D (which disturbs the microfilament system) on the production of intracellular second messengers. Cytochalasin D (CD) did not affect unstimulated calcium movements (measured by the45Ca efflux technique) or inositol phosphate production or cAMP accumulation. Neither did it modify the generation of intracellular second messengers induced by activation of the cholinergic muscarinic receptor (calcium and inositol phosphates). CD dit not affect the cAMP accumulation induced by the activation of the β‐adrenergic receptor whereas it strongly inhibited the calcium movements induced by activation of the same receptor. These data suggest that, in rat parotid glands, calcium movements, induced by β‐adrenergic receptor stimulation need an intact microfilament system to occur, whereas the muscarinic pathway (viaIP3) d

ISSN:0248-4900    

DOI:10.1111/j.1768-322X.1989.tb03010.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Summary—Oviduct implants from quails which were primarily stimulatedin vivoby estrogen so as to induce ciliogenesis in some epithelial cells were culturedin vitroin the presence or absence of colchicine or nocodazolc. After 24 or 48 hr of culture, implants were examined by transmission and scanning electron microscopy to determine drug‐induced alterations in ciliogenesis.After 24 hr of 10−5M colchicine treatment, the formation of basal bodies was totally inhibited, though the precursor material of generative complexes was unchanged. The inhibitory effect was not reversed when colchicine was removed in a 24 hr recovery culture. Treatment with 10−6M nocodazole for 24 hr, partially inhibited the assembly of basal bodies, which exhibited altered morphology. The assembly of basal bodies was restored during the 24 hr recovery period, after removal of nocodazole.Colchicine and nocodazole did not prevent polarized migration towards the apical surface of basal bodies formed prior to drug treatment. They anchored to the plasma membrane, but the formation of cilia was strongly disturbed in the presence of the drug. Numerous cells possessed anchored basal bodies which failed to induce the formation of cilia.The elongation of cilia was inhibited, as seen by their abnormal capping structure. In the enlarged tip, microtubules diverged. In contrast, these very short cilia possessed a mature ciliary necklace which was constructed during drug treatment. Differentiation of this membrane ciliary structure appeared to be unrelated to axoneme

ISSN:0248-4900    

DOI:10.1111/j.1768-322X.1989.tb03011.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Summary—Actin microfilaments were localized in quail oviduct ciliated cells using decoration with myosin subfragment S1and immunogold labeling. These polarized epithelial cells show a well developed cytoskeleton due to the prosence of numerous cilia and microvilli at their apical pole. Most S1‐decorated microfilaments extend from the microvilli downward towards the upper part of the ciliary striated rootlets with which they are connected. From the microvillous roots, a few microfilaments connect the proximal part of the basal body or the basal foot associated with the basal body. Microfilament polarity is shown by S1arrowheads pointing away from the microvillous tip to the cell body. Furthermore, short microfilaments are attached to the plasma membrane at the anchoring sites of basal bodies and run along the basal body. The polarity of these short microfilaments is directed from the basal body anchoring fibers downward to the cytoplasm. At the cell periphery, microfilaments from microvillous roots and ciliary apparatus are connected with those of the circumferential actin belt which is associated with the apical zonula adhaerens.Together with the other cytoskeletal elements, the microfilaments increase ciliary anchorage and could be involved in the coordination of ciliary beating. Moreover, microvilli surrounding the cilia probably modify ciliary beating by offering resistance to cilium bending. The presence of microvilli could explain the fact that mainly the upper part of the cilia appanars to be involved in the axonemal bending in metazoan ciliated ce

ISSN:0248-4900    

DOI:10.1111/j.1768-322X.1989.tb03012.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Summary—During wound‐healing in cultured frog skin fragments, fibronectin (FN) was detected in the dermal‐epidermal junction. Intracellular fibronectin was stained using permeabilization and DAB immunoperoxidase. With electron microscopy intracytoplasmic FN granules were localized in the epidermal processes of the stratum germinativum cells protruding towards the dermis and in their marginal regions (membrane‐associated plaques). Faint staining was visible at the level of the lamina densa and inside some parts of the lamina lucida. In comparison, contrasted ultrathin sections revealed classical disorganization of the dermal‐epidermal junction. In the presence of anti‐fibronectin serum during the whole time of culture, fibronectin‐antifibronectin binding was visualized in the form of sparse cytoplasmic granules in the epidermal processes of the stratum germinativum cells. Contrasted ultrathin sections emphasized the continuity between the tonofilaments, the anchoring filaments and the anchoring fibrils. Briefly, anti‐fibronectin serum inhibits the disorganization of the dermal‐epidermal junction in cult

ISSN:0248-4900    

DOI:10.1111/j.1768-322X.1989.tb03013.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY