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121.
The induction of congenital malformations among the offspring of male mice treated with X-rays at pre-meiotic and post-meiotic stages has been studied in two experiments. Firstly, animals were exposed to varying doses (108–504 cGy) of X-rays and mated at various time intervals (1–7, 8–14, 15–21 and 64–80 days post-irradiation), so as to sample spermatozoa, spermatids and spermatogonial stem cells. In the second experiment, only treated spermatogonial stem cells were sampled. One group of males was given a single 500-cGy dose, a second group a fractionated dose (500 + 500 cGy, 24 h apart) and a third group was left unexposed.In the first experiment, induced post-implantation dominant lethality increased with dose, and was highest in week 3, in line with the known greater radiosensitivity of the early spermatid stage. Preimplantation loss also increased with dose and was highest in week 3. There was no clear induction of either pre-implantation or post-implantation loss at spermatogonial stem cell stages.There was a clear induction of congenital malformations at post-meiotic stages, the overall incidence being 2.0 ± 0.32% in the irradiated series and 0.24 ± 0.17% among the controls. The induction was statistically significant at each dose. At the two highest doses the early spermatids (15–21 days) appeared more sensitive than spermatozoa, and at this stage the incidence of malformations increased with dose. The data from Expt. 1 on the induction of malformations by irradiation of spermatogonial stages were equivocal. In contrast, Expt. 2 showed a statistically significant induction of malformations at both dose levels (2.2 ± 0.46% after 500 cGy and 3.1 ± 0.57% after 500 + 500 cGy). The relative sensitivities of male stem cells, post-neiotic stages and mature oocytes to the induction of congenital malformations were reasonably similar to their sensitivities for specific-locus mutations, except that the expected enhancing effect of the fractionation regime used was not seen.Dwarfism and exencephaly were the two most commonly observed malformations in all series. 相似文献
122.
Summary In the montane herb Ipomopsis aggregata, size and placement of stamens and pistils vary substantially among flowers within plants, among nearby plants, and among groups of plants separated by 50–100 m. We trained captive hummingbirds to feed from flowers of this species in a flight cage, and explored the effects of different degrees of floral variability on carryover of fluorescent dyes that act as pollen mimics. We found that the slopes of linear dye carryover functions generally became more shallow as floral variability increased; this led to substantially longer carryover in the treatment with greatest variability. On the other hand, total amounts of dye transferred did not appear to be sensitive to the degree of variability. Floral variability may have a subtle but important effect on plant fitness by influencing the distance of pollen transfer. 相似文献
123.
Dennis Way Mary Hendrix Marlys Witte Charles Witte Ray Nagle John Davis 《In vitro cellular & developmental biology. Plant》1987,23(9):647-652
Summary An endothelial cell line derived from a massive recurrent chyle-containing retroperitoneal lymphangioma was isolated in monolayer
culture. Scanning and transmission electron microscopy and immunohistochemistry confirmed a close resemblance to blood vascular
endothelium with typical cobblestone morphology, positive immunofluorescence staining for endothelial marker Factor VIII-associated
antigen and fibronectin, and prominent Weibel-Palade bodies. The endothelial cells also exhibited other ultrastructural features
characteristic of lymphatic endothelium, including sparse microvillous surface projections, overlapping intercellular junctions,
and abundant intermediate filaments. This endothelial cell line represents a new source of proliferating lymphatic endothelium
for future study, including structural and functional comparison to blood vascular endothelium.
Supported in part by Arizona Disease Control Research Commission contracts 8277-000000-1-1-AT-6625 and ZB-7492. Presented
in part at the 10th International Congress of Lymphology in Adelaide, Australia, August 1985. 相似文献
124.
125.
The gene complex encoding the chain of the T-cell antigen receptor (Tcr) in man was previously reported to contain a restriction fragment length polymorphism (RFLP) involving a single Bgl II site adjacent to the second constant region gene. This RFLP allowed assignment of Tcr genotypes in certain human families. In the present study, two different RFLP in a V gene family were detected using the murine probe V8.1 in genomic DNA samples digested with the restriction endonucleases Hind III and Bam HI. Use of these RFLP to mark the V gene complex allowed complete haplotype assignment in four of seven families studied and provided support for linkage of the V gene complex to the constant region genes. Different combinations of the C and two V region markers can result in eight possible distinct haplotypes. The observation of all but one of the eight possible haplotypes in parents of the families studied suggests that recombination events occur between the C and V region and among members of the V region subfamily marked by the V8.1 probe. These markers can be used for mapping studies of the V gene complex in man and will allow an appraisal of possible associations between Tcr genes and disease susceptibility.Abbreviations used in this paper: Tcr
T-cell antigen receptor
- RFLP
restriction fragment length polymorphism
- C2
second Tcr constant region gene
- V
Variable
- C
constant
- J
joining
- D
diversity 相似文献
126.
We have studied the influence of DBA/2 non-H-2 antigens on the lethal graft-versus-host reaction (GVHR) developed across an H-2 barrier. (DBA/2 x B10.D2)F1 x B10.D2 (H-2
d) backcross (BC) mice were typed for their allelic constitution at nine genetically independent chromosome markers and used as individual cell donors simultaneously for two to three (DBA/2 X B10.D2)F1 recipients incompatible for DBA/2 non-H-2 antigens alone and two to three (DBA/2 x B10.BR)F1 recipients incompatible for DBA/2 non-H-2 antigens and H-2k. The results showed that, when compared with that developed in a control group incompatible for H-2
kalone [B10.D2(B10.D2xB10.BR)F1], the GVHR mortality seen in the presence of an additional incompatibility for DBA/2 non-H-2 antigens [(DBA/2 X B10.BR)F1recipients] is significantly delayed but only in female mice. An analysis of individual BC donors indicated that this protective effect of DBA/2 non-H-2 antigens correlates with incompatibility for gene(s) linked to the Pgm-1 chromosome marker. In contrast, incompatibility for gene(s) linked to Mod-1 and Es-3 markers accelerates GVHR mortality, but only in male mice. Finally, the results obtained with (DBA/2 x B10.D2)F1 and (DBA/2 x B10.BR)F1 recipients were compared; they showed that the intensity of the GVHR developed by cells from individual BC donors against a given set of DBA/2 non-H-2 antigens correlates well with that developed by the same BC donor against the same set of non-H-2 antigens plus H-2k. We conclude that certain non-H-2 genes (and antigens) can modulate the intensity of the GVHR developed across an H-2 barrier. The number of such genes is probably great; their effects are strong and complex, and can be sex-dependent. 相似文献
127.
The mechanisms underlying Ir gene control of CMI were addressed by examining the DTH and Tprlf responses specific for the synthetic polymers GT, GAT, and GA. We show that BALB/c mice (GAT/GA responders, GT nonresponders) primed with GT fail to develop DTH and Tprlf responses specific for GT, GAT, or GA. GAT immunization resulted in DTH responses that could be elicited not only with GAT and GA but also with GT, demonstrating that GT-specific TDH are present in nonresponder mice. GT-specific DTH was transferred with Thy-1+ Lyt-1+2–, H-2 Irestricted, nylon wool nonadherent cells. GA-primed BALB/c mice developed GAT- and GA-, but not GT-apecific DTH responses, indicating that GA and GT do not cross-react at the T-cell level. The ability of GAT [but not a mixture of GA plus GT, or GT electrostatically complexed to the immunogenic carrier MBSA (GT-MBSA)] to induce GT-specific DTH suggested a requirement for covalent linkage of stimulatory GA and nonstimulatory GT determinants present on the GAT molecule. Similarly, GT-specific in vitro Tprlf responses could be demonstrated in GAT-primed mice exhibiting significant levels of GT-specific DTH but not in GT- or GT-MBSA-primed mice. Tolerization experiments also suggested that GT-specific Th were involved in the development of GT-specific DTH in GAT-primed mice. The GT nonresponsiveness of BALB/c mice for DTH and Tprlf responses could not be reversed by treatments designed to abrogate Ts activity (priming with GT-MBSA and CY injection), nor could GT-primed cells be shown to inhibit the development or elicitation of GT-specific CMI in GAT-primed mice during the afferent and/or efferent stages of DTH. Our results suggest that GT nonresponsiveness does not result from the absence of GT-specific T cells or preferential induction of Ts. The results are discussed in the context of hole-in-the-repertoire and antigen presentation (determinant selection) models of Ir gene control.Abbreviations used in this paper APC
antigen-presenting cells
- BSA
bovine serum albumin
- BSS
Mishell-Dutton balanced salt solution
- CFA
complete Freund's adjuvant
- CMI
cell-mediated immunity
- CY
cyclophosphamide
- DTH
delayed-type hypersensitivity
- GA
poly(Glu60Ala40)
- GAT
poly (Glu60Ala30Tyr10)
- GT
poly(Glu50Tyr50)
- GT-MBSA
GT complexed to methylated bovine serum albumin
- It
immune response
- LN
lymph node
- PPD
purified protein derivative of tuberculin
- TDH
DTH T cells
- Th
helper T cells
- Tprlf
T-cell proliferation
- Ts
suppressor T cells
- TsF
T-cell suppressor factor(s) 相似文献
128.
Bolinopsis vitrea is a warm water lobate ctenophore which doesnot overlap in its distribution with Mnemiopsis mccradyi incontiguous waters. We examined its feeding ecology on a seriesof cruises. B. virrea ingested increasingly more prey at higherfood concentrations (2100 prey l1) but feedingeffort (clearance rate) decreased with increasing food availability.On a dry weight basis, smaller tentaculate Bolinopsis ingestedseveral times more than larger lobates, but based on carbonweight, specific ingestion was fairly uniform over the entiresize range investigated (660 mm total length). Bolinopsiscollected during the daytime in the Bahamas rarely had morethan three prey items in their guts. These results and laboratorymeasurements of digestion times (av. = 1.9 h) allowed computationof daily rations, which could not account for the metabolicrequirement as measured on the same cruises. Results of feedingexperiments, however, implied that prey densities in excessof 111 were sufficient to sustain a growing populationof Bolinopsis. Prey concentrations about an order of magnitudehigher were required for M. mccradyi based on similar experiments.These results were in general agreement with observed densitiesand distributions of ctenophores and their zooplankton preyin the Bahamas and coastal South Florida. 相似文献
129.
Summary The distribution of the vitamin-D dependent calcium-binding protein (Calbindin-D 28K) (CaBP-28K) in the tibial growth plate cartilage of the rat has been studied immunohistochemically using an antibody raised against rat renal CaBP-28K. The protein was detected mainly in the nuclei of chondrocytes and occasionally in the juxta-nuclear cytoplasm. The distribution was not uniform throughout the growth plate, but concentrated in the proliferatively active chondrocytes of the resting and proliferative zones. These findings raise the possibility that CaBP-28K may be involved in the mitotic activity of the chondrocytes, acting as a regulator of the proliferative process, perhaps via intranuclear calcium. 相似文献
130.
Diane S. Herson Balkumar Marthi Mary Anne Payer Dr. Katherine H. Baker 《Current microbiology》1986,13(2):77-80
Direct microscopic enumeration ofEnterobacter cloacae with the acridine orange 2-(p-iodophenyl)-3-(p-nitrophenyl)-5-phenyl tetrazolium chloride technique (AOINT) was compared with spread plate counts on nonselective media to establish the usefulness of the former technique in the enumeration of chlorine-stressed cells. Results indicate that the techniques are comparable when the organisms are not stressed. However, AOINT is more sensitive than are plate counts in the detection of chlorine-stressed cells. 相似文献