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41.
42.
Landraces of maize (Zea mays ssp. mays) and its wild teosinte relatives (Zea mays spp. parviglumis and mexicana) were surveyed for sensitivity to fumonisin B(1), a phytotoxin produced by the maize pathogen Gibberella moniliformis. Only two of 42 Z. mays samples were highly insensitive to FB(1) (ED(50) = ca. 200 microM). The teosintes and 76% of the maize landraces were moderately or highly sensitive to FB(1) (ED(50) < or = 30 microM), which indicates that FB(1) sensitivity is likely to be an ancestral trait in Z. mays. F(1) generations derived from crosses between FB(1)-sensitive maize inbred B73 and insensitive landraces were significantly less sensitive than B73. Thus, our data indicate that FB(1)-insensitivity is a relatively rare but heritable trait in maize. We also report the sensitivity of maize to other Gibberella toxins - beauvericin, diacetoxyscirpenol, and moniliformin. 相似文献
43.
Moreau E Fortin S Desjardins M Rousseau JL Petitclerc E C-Gaudreault R 《Bioorganic & medicinal chemistry》2005,13(24):1430-6712
In our ongoing research program aimed at the optimization of microtubule-self-assembly disrupting agents, we have prepared three series of phenylurea analogues (CEU), derived from N-(3-ω-hydroxyalkyl or 4-ω-hydroxyalkyl or 3-ω-hydroxyalkynyl)-phenyl-N′-(2-chloroethyl)ureas. Most compounds exhibit potent growth inhibitory activity on human colon carcinoma HT-29, human skin melanoma M21, and human breast carcinoma MCF-7 tumor cell lines, with a GI50 ranging from 250 nM to 8 μM. Among these new molecules, three CEUs exhibit GI50 in the nanomolar range. They are more potent by approximately an order of magnitude than previously described CEU analogues. As such, they are attractive hit compounds for the development of potent new alkylating antitubulin drugs. 相似文献
44.
Liliane?VenturaEmail author Gabriel?Torres?de Jesus Gunter?Camilo Dablas?de Oliveira Sidney?JF?Sousa 《Biomedical engineering online》2005,4(1):70
Background
The authors have developed a small portable device for the objective measurement of the transparency of corneas stored in preservative medium, for use by eye banks in evaluation prior to transplantation. 相似文献45.
Jutras I Laplante A Boulais J Brunet S Thinakaran G Desjardins M 《The Journal of biological chemistry》2005,280(43):36310-36317
Gamma-secretase is a high molecular mass protein complex that catalyzes the intramembrane cleavage of its protein substrates. Two proteins involved in phagocytosis, CD44 and the low density lipoprotein receptor-related protein, are gamma-secretase substrates, suggesting that this complex might regulate some aspects of phagocytosis. Our results indicate that the four components of gamma-secretase, viz. presenilin, nicastrin, APH-1, and PEN-2, are present and enriched on phagosome membranes from both murine macrophages and Drosophila S2 phagocytes. The gamma-secretase components form high molecular mass complexes in lipid microdomains of the phagosome membrane with the topology expected for the functional enzyme. In contrast to the majority of the phagosome proteins studied so far, which appear to associate transiently with this organelle, gamma-secretase resides on newly formed phagosomes and remains associated throughout their maturation into phagolysosomes. Finally, our results indicate that interferon-gamma stimulates gamma-secretase-dependent cleavages on phagosomes and that gamma-secretase activity may be involved in the phagocytic response of macrophages to inflammatory cytokines. 相似文献
46.
Fitzpatrick J.L.; Desjardins J.K.; Stiver K.A.; Montgomerie R.; Balshine S. 《Behavioral ecology》2006,17(1):25-33
In most cooperative breeders, dominants suppress the reproductionof subordinates. However, two previous studies of Neolamprologuspulcher, a cooperatively breeding cichlid fish, have suggestedthat socially subordinate helper males sneak fertilizationsfrom dominant breeding males. If such sneaking does occur, boththeoretical work and empirical studies of other fish speciessuggest that sperm competition will select for increased reproductiveinvestment by sneaker males, relative to more dominant males.To address these issues, we quantified gonadal investment andsperm characteristics of 41 N. pulcher male breeders and 62male helpers from 55 groups in Lake Tanganyika. Gonadal investmentfollowed patterns consistent with reproductive suppression,with breeders having considerably larger testes masses thanhelpers. Breeders also had faster and longer swimming spermand a higher percentage of motile sperm compared to helpers.However, sperm characteristics of large helpers were similarto those of breeders, but these same helpers had lower testesmasses. Thus, large helpers had sperm that were physiologicallyequivalent to that of breeders, but their relatively small gonadsimply that they were reproductively suppressed. 相似文献
47.
Leishmania antigens are presented to CD8+ T cells by a transporter associated with antigen processing-independent pathway in vitro and in vivo 总被引:1,自引:0,他引:1
Bertholet S Goldszmid R Morrot A Debrabant A Afrin F Collazo-Custodio C Houde M Desjardins M Sher A Sacks D 《Journal of immunology (Baltimore, Md. : 1950)》2006,177(6):3525-3533
CD8+ T cells are generated in response to Leishmania major (Lm) or Toxoplasma gondii parasitic infections, indicating that exogenously delivered Ag can be processed for presentation by MHC class I molecules. We show that presentation of Lm nucleotidase (NT)-OVA is TAP independent in vivo and in vitro, and is inhibited by chloroquine, but not by proteasome inhibitors. In contrast, the presentation of T. gondii P30-OVA relies on the TAP/proteasome pathway. Presentation of OVA- or rNT-OVA-coated beads also bypassed TAP requirement above a certain Ag threshold. TAP was also dispensable for the presentation of wild-type Lm Ags to primed CD8+ T cells in vitro. Finally, in vivo priming of CD8+ T cells involved in acquired resistance to Lm was not compromised in TAP-deficient mice. Thus, Leishmania Ags appear to be confined to an intraphagosomal processing pathway that requires higher concentrations of Ags, suggesting that these parasites may have evolved strategies to impair the efficient endoplasmic reticulum-based, TAP-dependent cross-presentation pathway to avoid or delay CD8+ T cell priming. 相似文献
48.
Maize (Zea mays) is an important food crop in the foothills of the Nepal Himalaya Mountains. Surveys have found that maize in Nepal is contaminated
withFusarium species, mainlyF. verticillioides andF. proliferatum, which produce fumonisins, andF. graminearum, which produces trichothecenes, mainly nivalenol and 4-deoxynivalenol. Maize from smallholder farms and markets is often
contaminated with fumonisins and trichothecenes above 1000 ng/g, a level of concern for human health. These mycotoxins were
not eliminated by traditional fermentation for producing maize beer, but Nepalese women were able to detoxify contaminated
maize by hand-sorting visibly disease kernels. An integrated approach to reduce mycotoxins risks in maize in Nepal and other
developing countries should include plant breeding to produce ear rot resistant cultivars, along with education in mycotoxins
risks and in agricultural and grain storage practices to reduce mycotoxin contamination.
Presented at the EU-USA Bilateral Workshop on Toxigenic Fungi & Mycotoxins, New Orleans, USA, July 5–7, 2005 相似文献
49.
RP Tucker K Drabikowski JF Hess J Ferralli R Chiquet-Ehrismann JC Adams 《BMC evolutionary biology》2006,6(1):60-17
Background
Tenascins are a family of glycoproteins found primarily in the extracellular matrix of embryos where they help to regulate cell proliferation, adhesion and migration. In order to learn more about their origins and relationships to each other, as well as to clarify the nomenclature used to describe them, the tenascin genes of the urochordate Ciona intestinalis, the pufferfish Tetraodon nigroviridis and Takifugu rubripes and the frog Xenopus tropicalis were identified and their gene organization and predicted protein products compared with the previously characterized tenascins of amniotes. 相似文献50.