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131.
STEVEN P. PAKES JOHN A. SHADDUCK ANN CALI 《The Journal of eukaryotic microbiology》1975,22(4):481-488
SYNOPSIS. Fine structure and development of Encephalitozoon cuniculi from rabbits were studied in rabbit choroid plexus (CP) cell cultures and were compared to hamster and mouse microsporida. Sporoplasms had a single limiting membrane and contained a large nucleus. Proliferative forms (schizonts) had double outer membranes, the outermost being associated with the formation of the limiting membrane of vacuoles formed within the host cell cytoplasm. These organisms were often binucleate and divided to form sporonts. Sporonts divided once to form 2 sporoblasts which developed into electron-dense spores. Spores had a thick, 3-layered wall and contained a polar filament. The developmental cycle of E. cuniculi in rabbit CP cultures progressed rapidly. Sporoplasms were observed in host cells at 3 hr postinoculation (PI). By 24 hr PI proliferative forms were associated with host cell cytoplasmic vacuoles which contained developing organisms. Mature spores were present in vacuoles by 2 days PI, indicating that the life cycle in the CP system is ∼ 48 hr. The fine structure and the sequential developmental cycle of the mouse and hamster isolates were observed to be identical to those of the rabbit isolate and different from those of the genus Nosema. It is proposed, therefore, that the 3 organisms represent the same species, Encephalitozoon cuniculi. 相似文献
132.
XIAOLONG ZHU MURRAY WITTNER HERBERT B. TANOWITZ ANN CALI LOUIS M. WEISS 《The Journal of eukaryotic microbiology》1994,41(3):204-209
ABSTRACT. The microsporidian species Enterocytozoon bieneusi, Septata intestinalis and Ameson michaelis were compared by using sequence data of their rRNA gene segments, which were amplified by polymerized chain reaction and directly sequenced. The forward primer 530f (5'-GTGCCATCCAGCCGCGG-3') was in the small subunit rRNA (SSU-rRNA) and the reverse primer 580r (5'-GGTCCGTGTTTCAAGACGG-3') was in the large subunit rRNA (LSU-rRNA). We have utilized these sequence data, the published data on Encephalitozoon cuniculi and Encephalitozoon hellem and our cloned SSU-rRNA genes from E. bieneusi and S. intestinalis to develop a phylogenetic tree for the microsporidia involved in human infection. The higher sequence similarities demonstrated between S. intestinalis and E. cuniculi support the placement of S. intestinalis in the family Encephalitozoonidae. This method of polymerized chain reaction rRNA phylogeny allows the establishment of phylogenetic relationships on limiting material where culture and electron microscopy are difficult or impossible and can be applied to archival material to expand the molecular phylogenetic analysis of the phylum Microspora. In addition, the highly variable region (E. coli numbering 590–650) and intergenic spacer regions in the microsporidia were noted to have structural correspondence, suggesting the possibility that they are coevolving. 相似文献
133.
MAMTA KALRA ULRIKE GERDEMANN JESSICA D. LUU MINTHRAN C. NGO ANN M. LEEN CHRYSTAL U. LOUIS CLIONA M. ROONEY STEPHEN GOTTSCHALK 《Cytotherapy》2019,21(2):212-223
Background aims
EBV type II latency tumors, such as Hodgkin lymphoma (HL), Non-Hodgkin lymphoma (NHL) and nasopharyngeal carcinoma, express a limited array of EBV antigens including Epstein-Barr nuclear antigen (EBNA)1, latent membrane protein (LMP)1, LMP2, and BamH1-A right frame 1 (BARF1). Adoptive immunotherapy for these malignancies have focused on EBNA1, LMP1 and LMP2 because little is known about the cellular immune response to BARF1.Methods
To investigate whether BARF1 is a potential T-cell immunotherapy target, we determined the frequency of BARF1-specific T-cell responses in the peripheral blood of EBV-seropositive healthy donor and patients with EBV-positive malignancies, mapped epitopes and evaluated the effector function of ex vivo–generated BARF1-specific T-cell lines.Results
BARF1-specific T cells were present in the peripheral blood of 12/16 (75%) EBV-positive healthy donors and 13/20 (65%) patients with EBV-positive malignancies. Ex vivo expanded BARF1-specific T-cell lines contained CD4- and CD8-positive T-cell subpopulations, and we identified 23 BARF1 peptides, which encoded major histocompatibility complex class I– and/or II–restricted epitopes. Epitope mapping identified one human leukocyte antigen (HLA)-A*02-restricted epitope that was recognized by 50% of HLA-A*02, EBV-seropositive donors and one HLA-B*15(62)-restricted epitope. Exvivo expanded BARF1-specific T cells recognized and killed autologous, EBV-transformed lymphoblastoid cell lines and partially HLA-matched EBV-positive lymphoma cell lines.Discussion
BARF1 should be considered as an immunotherapy target for EBV type II (and III) latency. Targeting BARF1, in addition to EBNA1, LMP1 and LMP2, has the potential to improve the efficacy of current T-cell immunotherapy approaches for these malignancies. 相似文献134.
Correlations of stomatal conductance with hydraulic and chemical factors in several deciduous tree species in a natural habitat 总被引:2,自引:0,他引:2
ROBERT M. AUGÉ CRAIG D. GREEN ANN J. W. STODOLA ARNOLD M. SAXTON JOSHUA B. OLINICK & RICHARD M. EVANS 《The New phytologist》2000,145(3):483-500
Recent research in whole-plant stomatal physiology, conducted largely with potted plants in controlled environments, suggests that stomatal conductance ( g s ) might be more closely linked to plant chemical variables than to hydraulic variables. To test this in a field situation, seasonal g s was examined in relation to a number of plant and environmental variables in 11 temperate, deciduous forest tree species. Stomatal conductance was generally better correlated with environmental variables (air temperature, vapor pressure deficit, PPFD) than with plant variables, and slightly better correlated with plant hydraulic variables (shoot water and osmotic potentials) than with plant chemical variables (xylem sap ABA concentration, xylem sap pH). We examined a model, developed previously for maize, which describes regulation of g s by xylem sap ABA concentration with leaf water status acting to modify stomatal sensitivity to the ABA signal. This model explained slightly more variation in seasonal g s in the forest trees than did single plant variables but not more variation than most single environmental variables. Response surface models, especially those incorporating environmental variables, were more consistently successful at explaining g s across species. 相似文献
135.
136.
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138.
Effects of maternal diet quality on offspring performance in the rove beetle Tachyporus hypnorum 总被引:1,自引:0,他引:1
Abstract. 1. The reproductive output of an individual is known to be influenced by diet quality, but the quality of the parent's diet can also influence the performance of the offspring. Dietary maternal effects may interact with the effects of the offspring's diet to produce a variety of response patterns.
2. Maternal effects were investigated in a polyphagous predator, the rove beetle Tachyporus hypnorum , using three single-species diets: two low-quality diets consisting of the aphids Sitobion avenae and Rhopalosiphum padi , and the high-quality control Drosophila melanogaster diet. Offspring of females fed these diets were raised on the same monotypic diets and allowed to reproduce. Several fitness parameters were measured to indicate possible maternal effects in both F1 and F2 generations.
3. Maternal diet effects in F1 were found in egg size, hatching success, time to hatching, larval development time, larval survival, and sex ratio. Both aphid diets resulted in smaller eggs. A diet of R. padi resulted in reduced hatching success, longer time spent in the egg stage, and a female-biased sex ratio. A maternal diet of R. padi also prolonged larval development on S. avenae diet, while a maternal diet of S. avenae decreased survival on the R. padi diet. These effects were independent of egg size.
4. A maternal diet of R. padi enhanced the survival of F1 larvae raised on the same diet. Developmental selection operating through a high egg mortality may be the explanation for this seemingly positive effect.
5. Sitobion avenae alone caused a significant reduction in the hatching success of F2 eggs, thus revealing grandmaternal effects.
6. The prediction that polyphagous predators are less likely to evolve adaptive maternal effects is supported by the fact that none of the documented maternal effects could be interpreted as adaptive. 相似文献
2. Maternal effects were investigated in a polyphagous predator, the rove beetle Tachyporus hypnorum , using three single-species diets: two low-quality diets consisting of the aphids Sitobion avenae and Rhopalosiphum padi , and the high-quality control Drosophila melanogaster diet. Offspring of females fed these diets were raised on the same monotypic diets and allowed to reproduce. Several fitness parameters were measured to indicate possible maternal effects in both F1 and F2 generations.
3. Maternal diet effects in F1 were found in egg size, hatching success, time to hatching, larval development time, larval survival, and sex ratio. Both aphid diets resulted in smaller eggs. A diet of R. padi resulted in reduced hatching success, longer time spent in the egg stage, and a female-biased sex ratio. A maternal diet of R. padi also prolonged larval development on S. avenae diet, while a maternal diet of S. avenae decreased survival on the R. padi diet. These effects were independent of egg size.
4. A maternal diet of R. padi enhanced the survival of F1 larvae raised on the same diet. Developmental selection operating through a high egg mortality may be the explanation for this seemingly positive effect.
5. Sitobion avenae alone caused a significant reduction in the hatching success of F2 eggs, thus revealing grandmaternal effects.
6. The prediction that polyphagous predators are less likely to evolve adaptive maternal effects is supported by the fact that none of the documented maternal effects could be interpreted as adaptive. 相似文献
139.
Relative contributions of environmental and maternal factors to trans‐generational immune priming in T. castaneum 下载免费PDF全文
1. Trans‐generational immune priming is a phenomenon in insects in which the offspring of mothers previously challenged with a focal microbe exhibit a survival advantage when challenged with that microbe. 2. Maternal egg provisioning with immune factors such as antimicrobial peptides (AMPs) is widely believed to contribute to the primed phenotype. However, other ‘socially mediated’ environmental factors secreted or excreted by the mother and others in the community, such as the gut microbiota or pheromones, may also affect offspring immune phenotype. 3. The relative contributions of maternal egg provisioning and socially mediated environmental factors to the primed larval phenotype were assessed by performing a cross‐fostering survival experiment with Tribolium castaneum, in which the eggs of primed or naïve mothers were sterilised, treated with the frass of primed or naïve beetles, and challenged as larvae with the maternal pathogen, Bacillus thuringiensis. 4. Larvae from primed mothers showed greater survival than unprimed larvae, regardless of frass treatment; maternal treatment therefore showed a substantially greater contribution to larval priming than frass treatment. 5. Planned contrast tests to quantify the contributions of maternal and environmental matching revealed that maternal treatment mattered more for larvae exposed to primed, rather than unprimed, frass. This suggests that the effects of maternal egg provisioning may be exacerbated or mitigated by environmental factors. 6. Thus, although maternal egg provisioning plays a predominant role in producing the primed phenotype, environmental matching may matter for priming in some contexts. 相似文献
140.