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YVON CROISILLE MADELEINE GUMPEL-PINOT JEAN-MARIE GASC 《Differentiation; research in biological diversity》1978,11(1-3):39-49
By means of purified rabbit anti-adult chicken kidney antibodies two types of antigens have been identified in the mesonephros: one (PS), localized in the cells of the proximal secretory tubules, the other (CT) characteristic of the collecting segments.
During the conversion of certain mesonephric tubules into epididymal ductules in the male, the CT-antigen disappears, whereas the PS-antigen not only persists but can also be detected in the cells of the parietal layers of Bowman's capsules as they transform before connecting with the rete testis. In the adult cock, the PS-antigen is found at the apical part of the cells of the ductuli efferentes, whereas the ductuli conjugentes and ductus epididymidis are negative.
In the female, the PS-antigen is also found to persist in the cells of the proximal segment and to appear in the cells of the parietal layers of Bowman's capsules. However, between 2 and 3 months after hatching it disappears, although perfectly well preserved tubuli of mesonephric origin can be observed at much later stages.
In the epididymal tubuli of the sexually mature cock, large sheets of the epithelial walls are seen to detach and to fall into the lumina where they disintegrate. The cellular contents thus released mix with the mass of the spermatozoa. Arguments tending to exclude a fixation artifact are presented and the possibility that the observation reflects a cyclic physiological process is discussed. 相似文献
During the conversion of certain mesonephric tubules into epididymal ductules in the male, the CT-antigen disappears, whereas the PS-antigen not only persists but can also be detected in the cells of the parietal layers of Bowman's capsules as they transform before connecting with the rete testis. In the adult cock, the PS-antigen is found at the apical part of the cells of the ductuli efferentes, whereas the ductuli conjugentes and ductus epididymidis are negative.
In the female, the PS-antigen is also found to persist in the cells of the proximal segment and to appear in the cells of the parietal layers of Bowman's capsules. However, between 2 and 3 months after hatching it disappears, although perfectly well preserved tubuli of mesonephric origin can be observed at much later stages.
In the epididymal tubuli of the sexually mature cock, large sheets of the epithelial walls are seen to detach and to fall into the lumina where they disintegrate. The cellular contents thus released mix with the mass of the spermatozoa. Arguments tending to exclude a fixation artifact are presented and the possibility that the observation reflects a cyclic physiological process is discussed. 相似文献
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BIANCO-TRINCHANT JACQUELINE; GUIGONIS JEAN-MARIE; PAGE-DEGIVRY MARIE-THERESE LE 《Journal of experimental botany》1993,44(5):957-962
During the isolation of rose petal protoplasts, two successivetransient abscisic acid (ABA) accumulations were detected whendigest medium and tissue slices were assayed simultaneously,using polyclonal antibodies raised against (+)-ABA. Late accumulation,occurring after more than 1 h of incubation, was observed, whetherenzymes were present or not, in a hyperosmotic medium. Veryearly accumulation, occurring at a maximum of 15 min after thebeginning of incubation, was observed only in the presence ofcellulolytic and pectinolytic enzymes. The ABA level could beincreased by the addition of tetcyclacis, an inhibitor of mono-oxygenaseknown to delay ABA oxidation. The need for cell wall digestingenzymes to observe this first ABA increase suggested that itwas due to a release from the cell wall. Analysis by radioimmunoassay(RIA) and high performance liquid chromatography (HPLC) showedthat ABA and another non-acidic immunoreactive compound werereleased from purified cell walls by the same enzymes. Key words: ABA, cell wall, protoplast, rose petal 相似文献
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Inflorescence size was investigated in a range of apple treecultivars. Each inflorescence size was quantified by the numberof foliage leaves and flowers. A first analysis was carriedout usingdependence stereogramsand standardized non-parametriccorrelation coefficients, based on Kendall 's 相似文献
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Soil carbon storage potential of direct seeding mulch-based cropping systems in the Cerrados of Brazil 总被引:1,自引:0,他引:1
MARC CORBEELS † ERIC SCOPEL † ALEXANDRE CARDOSO† MARTIAL BERNOUX‡ JEAN-MARIE DOUZET§ MARCOS SIQUEIRA NETO¶ 《Global Change Biology》2006,12(9):1773-1787
No‐tillage cropping systems with direct seeding into a mulch of plant residues from cover crops – the so‐called direct seeding mulch‐based cropping (DMC) systems – have been adopted widely over the last 10–15 years in the Cerrado region of Brazil. They are replacing the traditional soybean monoculture with bare fallow using conventional tillage (CT) practices. The objective of this study was to examine how DMC practices affect soil organic carbon (SOC) dynamics and to assess their potential for enhanced soil carbon (C) storage. The approach was to determine soil C stocks along a chronosequence of fields under DMC, and then to apply the generic decomposition and yield (G'DAY) plant–soil model to analyse the soil C storage potential for a number of cropping systems. Forty‐five fields were selected on a plateau of Ferralsols in the central Cerrado region to represent a chronosequence of 0–12 years under continuous DMC. Before DMC the fields had been under CT soybean monoculture following the clearing of the native savannah. An average increase in SOC stocks of 0.83 Mg C ha?1 yr?1 in the 0–20 cm topsoil was measured. The corresponding increase in total soil nitrogen was 79 kg N ha?1 yr?1. The G'DAY model predicted a net accumulation of 0.70–1.15 Mg C ha?1 yr?1 in the 0–40 cm topsoil for the first 12 years, depending on the type of soil and DMC system. Model predictions showed that less soil C was accumulated under DMC systems that commenced immediately after clearing the native savannah. Gains in soil C under DMC were primarily due to the introduction of a second crop that caused higher net primary productivity, leading to higher plant C inputs to soil. A rough estimation shows that the conversion of 6 million ha of CT soybean monoculture to DMC in the Cerrados would enhance soil C storage by 4.9 Tg C yr?1 during at least the first 12 years following the conversion to DMC. 相似文献
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IT has been a source of speculation whether the reading of the genetic code of DNA by RNA polymerase involves the disruption of the DNA helix. While circuitous evidence favouring either affirmative or negative answer has been accumulating, direct experiments have been few1–11. Kosaganov et al. investigated the possibility of a local unwinding of DNA during RNA synthesis by measuring the kinetics of formaldehyde-induced denaturation of DNA during RNA synthesis12. They concluded that the binding of RNA polymerase did not cause local unwinding but RNA synthesis produced “defects” in the double helix. Unfortunately, the interpretation of formaldehyde-induced denaturation is not clear, nor is the nature of a “defect”. 相似文献
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CECILE POMPORT-CASTILLON CHARLES GASC BERNARD ROMESTAND 《The Journal of eukaryotic microbiology》1997,44(6):643-648
ABSTRACT. Monoclonal antibodies against spores of Glugea atherinae were obtained after lymphocytic hybridization made from immunized mouse splenocytes. Screening using an indirect enzyme linked immunosorbent assay (ELISA), revealed seven monoclonal antibodies with an intense but variable reaction with the spores of fish microsporidia, and a moderate reaction with those of an insect microsporidium (Nosema sp.). The reaction was weaker with spores of Encephalitozoon intestinalis found in HIV' patients. FITC and Dot Blot confirmed the majority of these results. After biotinylation of the seven antibodies, inhibition tests allowed the localization of two different recognition domains on the spores of Glugea atherinae . The multiple antigenic determinants and their probable polysaccharide nature seem to be in accord with the class IgM of the antibodies produced. This work confirms the potential of these antibodies for microsporidian taxonomy and diagnosis, especially the use of Mabs 12F9 and 12H5 for detection of spores in stools of HIV+ patients. 相似文献
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With 76% of its 3063 native species of flora endemic, the New Caledonia biodiversity hotspot has long been recognized as having a high potential for conservation. Under the new IUCN Red List categories, 25% of the endemic plants are at risk (Conservation Dependent, Vulnerable, Endangered, Critically Endangered), and five species are already extinct. A review of their distribution demonstrates that 83% of the threatened species do not occur at all in a conservation area, and only 11% have their conservation status improved by a protected area. The protected area network is geographically and floristically very unbalanced, with the rainforest and high altitude maquis in the south concentrating most of the conservation effort. Conversely, the middle and northern segments of the island, as well as all of the dry west coast, are left without adequate conservation area. Two vegetation types, the sclerophyll forest and the unique low/middle altitude maquis, are virtually totally unprotected. We conclude that the current network of protected areas needs to be considerably expanded, in terms of both geographical/floristic subregions within New Caledonia and vegetation type covered. With only 54% of the conservation area covered by strict mining restrictions, existing reserves need to have their conservation efficiency improved by a more vigorous enforcement of their status, and by extending mining bans to all of them. 相似文献
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JEAN-MARIE GASC MADHABANANDA SAR 《Differentiation; research in biological diversity》1981,20(1-3):77-80
The differentiation of the pituitary of the chicken embryo was studied by means of an immunohistochemical technique using antisera to turkey and chicken pituitary hormones. Immunoreactive LH-cells are detected in 4-day embryos (stage 23 of Hamburger and Hamilton) when the primordium of the anterior pituitary, the Rathke's pouch is only composed of a single-layer epithelium lined with an undifferentiated mesenchyme. A few immunoreactive cells are observed grouped on the posterior aspect of the pouch. As development proceeds, a strip of positive cells is detected encircling the Rathke's pouch. Prolactin-, growth hormone-, and ACTH-immunoreactive cells are detected in 6- and 7-day embryos, only after the pituitary has acquired its characteristic structure with cords in which different cell types become progressively recognizable. The early appearance of immunoreactive LH-cells following a precise distribution shows that secretory properties and differentiation capacities are acquired simultaneously in the epithelium of the Rathke's pouch and may be induced by the same stimulus. 相似文献
10.
V. L. BELS J.-P. GASC VÉRONIQUE GOOSSE SABINE RENOUS and R. VERNET 《Journal of Zoology》1995,236(1):95-116
The threat behaviour in Varanus griseus was investigated with high-speed cinematography and X-ray films. Lizards exhibit threat display involving throat movements and associated throat, thorax and mouth movements. The functional anatomy of the bucco-pharyngeal region is described and threat displays are kinematically studied and functionally interpreted. 相似文献