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991.
992.
This is the first report of Harpellales (Zygomycota) from Mexico, including herein only the endosymbiotic species of gut fungi in the digestive tracts or shed exuviae of Plecopteran and Ephemeropteran nymphs. Four new species are described: Allantomyces zopilotei, Bojamyces olmecensis, Gauthier-omyces viviparus and Graminella ophiuroidea. Among previously known Harpellales, Lancisporomyces nemouridarum and Zygopolaris ephemeridarum are southern range extremes and new records for Mexico. All species are illustrated and discussed relating to biogeographic implications of the new reports from Mexico, as well as the particular environmental circumstances of the Harpellales in the tropics. 相似文献
993.
骨质疏松等中老年的常见病和多发病也呈年轻化发展,如何进行有效的骨状况诊断,拥有一台可以信赖的、可以方便地应用的骨测量仪器显得更为重要。超声波骨测量技术是使用范围比较广泛的一种,本文对超声波测量法的最新发展进行了阐述。 相似文献
994.
995.
996.
Local delivery of IL-12 and GM-CSF to advanced primary tumors results in T- and NK-cell-dependent cure of disseminated disease
in a murine spontaneous lung metastasis model. Post-therapy functional dynamics of cytotoxic T- and NK-cells were analyzed
in primary and metastatic tumors to determine the specific roles of each subset in tumor eradication. Time-dependent depletion
of CD8+ T and NK-cells demonstrated that CD8+ T-cells were critical to eradication of metastatic tumors within 3 days of treatment,
but not later. In contrast, NK-cells were found to be essential to tumor regression for at least 10 days after cytokine delivery.
Analysis of tumor-infiltrating lymphocyte populations in post-therapy primary tumors demonstrated that treatment resulted
in the activation of tumor-associated CD8+ T-cells within 24 h as determined by IFNγ and perforin production. T-cell activity
peaked between days 1 and 3 and subsided rapidly thereafter. Activation was not accompanied with an increase in cell numbers
suggesting that treatment mobilized pre-existing T-effector/memory cells without inducing proliferation. In contrast, therapy
resulted in a ≥3-fold enhancement of both the quantity and the cytotoxic activity of NK-cells in primary and metastatic tumors
on day 3 post-therapy. NK-cell activity was also transient and subsided to pre-therapy levels by day 5. Depletion of CD4+
and CD8+ T-cells prior to treatment completely abrogated NK-cell infiltration into primary and metastatic tumors demonstrating
the strict dependence of NK-cell recruitment on pre-existing T-effector/memory cells. Treatment failed to induce significant
NK-cell infiltration in IFNγ-knockout mice establishing the central role of IFNγ in NK-cell chemotaxis to tumors. These data
show that transient activation of tumor-associated T-effector/memory and NK-cells, but not long-term CD8+ T-cell responses,
are critical to suppression of metastatic disease in this model; and reveal a novel role for pre-existing adaptive T-cell
immunity in the recruitment of innate effectors to tumors.
This work was supported by NIH/NCI grant R01-CA100656-01A1 to N.K.E. 相似文献
997.
Marquez A Villa-Treviño S Guéraud F 《Redox report : communications in free radical research》2007,12(1):35-39
Growing evidence indicates oxidative stress as a mechanism of several diseases including cancer. Oxidative stress can be defined as the imbalance between cellular oxidant species production and antioxidant capability shifted towards the former. Lipid peroxidation is one of the processes that takes place during oxidative stress. Lipid peroxidation products, such as malondialdehyde (MDA) and 4-hydroxy-2-nonenal (HNE), are closely related to carcinogenesis as they are potent mutagens and they have been suggested as modulators of signal pathways related to proliferation and apoptosis, two processes implicated in cancer development. Mechanisms by which oxidative stress leads to tumor formation are still under investigation. The need of suitable in vivo models that could reflect that inflammation-related human carcinogenesis is evident. In this regard, the mutant strain Long Evans Cinnamon-like (LEC) rat provides a promising model for investigation of the relationship between hepatitis induced by oxidative stress and hepatocarcinogenesis because it has been demonstrated to develop spontaneous liver tumor formation related to copper accumulation and oxidative stress. In this review, the findings regarding oxidative stress and its relation with liver pathologies in LEC rats are discussed; we focus on the mechanisms proposed for HNE carcinogenesis. 相似文献
998.
Kejian Wang Ding Tang Lilan Hong Wenying Xu Jian Huang Ming Li Minghong Gu Yongbiao Xue Zhukuan Cheng 《PLoS genetics》2010,6(1)
Sexual reproduction is essential for the life cycle of most angiosperms. However, pseudovivipary is an important reproductive strategy in some grasses. In this mode of reproduction, asexual propagules are produced in place of sexual reproductive structures. However, the molecular mechanism of pseudovivipary still remains a mystery. In this work, we found three naturally occurring mutants in rice, namely, phoenix (pho), degenerative palea (dep), and abnormal floral organs (afo). Genetic analysis of them indicated that the stable pseudovivipary mutant pho was a double mutant containing both a Mendelian mutation in DEP and a non-Mendelian mutation in AFO. Further map-based cloning and microarray analysis revealed that dep mutant was caused by a genetic alteration in OsMADS15 while afo was caused by an epigenetic mutation in OsMADS1. Thus, OsMADS1 and OsMADS15 are both required to ensure sexual reproduction in rice and mutations of them lead to the switch of reproductive habit from sexual to asexual in rice. For the first time, our results reveal two regulators for sexual and asexual reproduction modes in flowering plants. In addition, our findings also make it possible to manipulate the reproductive strategy of plants, at least in rice. 相似文献
999.
1000.