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991.
Yukio Takahata Naoki Koyama Naomi Miyamoto Megumi Okamoto 《Primates; journal of primatology》2001,42(3):267-271
In the Berenty Reserve, Southern Madagascar, of the 16 deliveries recorded for ring-tailed lemurs from 1995 and 1997, 10 cases
occurred during daytime hours (07:00 – 16:59). Four mothers lost contact with their troop members during parturition, but
were able to rejoin them after about one hour. No attack from the individuals of the neighboring groups or predators on the
mothers or their newborn infants was observed, whereas, other females of the mother’s own troop attacked them after delivery
in two cases. Such daytime delivery may have originated from the circadian rhythm of the species’ nocturnal ancestors, who
might have given birth during the daytime. This pattern may now be a non-adaptive feature, in agreement with the “evolutionary
disequilibrium hypothesis (EVDH).” 相似文献
992.
Y Fujino T Nagahama T Oumi K Ukena F Morishita Y Furukawa O Matsushima M Ando H Takahama H Satake H Minakata K Nomoto 《The Journal of experimental zoology》1999,284(4):401-406
Annetocin is an earthworm oxytocin-related peptide that we previously isolated from the whole body of a lumbricid earthworm Eisenia foetida. We have reported that annetocin induces egg-laying-like behaviors in E. foetida and a gnathobdellid leech, Whitmania pigra, when it is injected into the respective animals. The present study was undertaken to probe physiological functions of invertebrate oxytocin-vasopressin-superfamily peptides with special reference to reproductive and osmoregulatory events in which vertebrate peptides of this superfamily are involved. Annetocin, Lys-conopressin (a leech vasopressin-related peptide) and two analog peptides, [Tyr(3)]-annetocin ((3)Y-annetocin) and [Phe(3)]-annetocin ((3)F-annetocin), were compared for their activities to induce egg-laying-like behavior and to change body weight as a measure of water balance in the leech W. pigra. Injection of annetocin, Lys-conopressin, and (3)F-annetocin caused both egg-laying-like behavior and reduction of body weight in the animals, but (3)Y-annetocin induced neither. Furthermore, leeches in the non-breeding season responded to peptides less conspicuously than those in the breeding season. Such a concomitant induction of egg-laying-like behavior and body-weight reduction suggests that these two phenomena are unitary and might be accounted for by the fact that egg-laying in leeches and earthworms is accompanied by secretion of a large quantity of mucus, which should significantly contribute to body-weight loss. J. Exp. Zool. 284:401-406, 1999. 相似文献
993.
Photosynthetic and stomatal responses of two tropical and two temperate trees to atmospheric humidity 总被引:4,自引:0,他引:4
The effects of leaf to air vapour pressure differences (ΔW) on net photosynthetic rate (PN) and stomatal conductance (gs) were examined in the leaves of two tropical rain forest trees, Eugenia grandis and Pongamia pinnata, and two temperate evergreen
trees, Viburnum awabuki and Daphniphyllum macropodum. A single leaf was set inside a small chamber and ΔW was varied from
7 to 24 mmol mol-1 at 25 and 500 μmol m-2 s-1 of photon flux density. PN and gs of the two tropical rain forest trees decreased with increasing ΔW, while the two temperate evergreen trees were not highly
responsive to ΔW. P. pinnata was more sensitive to ΔW in its stomatal response, and had a higher stomatal density and higher
stomatal index than did the two temperate trees and another tropical tree. Significant reductions i n gs and intercellular CO2 concentrations in the two tropical trees at high ΔW suggest that the decline of PN was due to the decrease in gs. The responses of PN and gs indicated that the tropical trees were more sensitive to ΔW than were the temperate ones.
This revised version was published online in September 2006 with corrections to the Cover Date. 相似文献
994.
Junki Maruyama Rachel A. Reyna Megumi Kishimoto-Urata Shinji Urata John T. Manning Nantian Harsell Rebecca Cook Cheng Huang Janko Nikolich-Zugich Tomoko Makishima Slobodan Paessler 《PLoS pathogens》2022,18(5)
Lassa virus (LASV) is the causative agent of Lassa fever (LF), which presents as a lethal hemorrhagic disease in severe cases. LASV-induced hearing loss in survivors is a huge socioeconomic burden, however, the mechanism(s) leading to hearing loss is unknown. In this study, we evaluate in a mouse LF model the auditory function using auditory brainstem response (ABR) and distortion product otoacoustic emissions (DPOAE) to determine the mechanisms underlying LASV-induced hearing loss. In the process, we pioneered measures of ABR and DPOAE tests in rodents in biosafety level 4 (BSL-4) facilities. Our T cell depletion studies demonstrated that CD4 T-cells play an important role in LASV-induced hearing loss, while CD8 T-cells are critical for the pathogenicity in the acute phase of LASV infection. Results presented in this study may help to develop future countermeasures against acute disease and LASV-induced hearing loss. 相似文献
995.
K Hasunuma K Furukawa K Tomita C Mukai T Nakamura 《Biochemical and biophysical research communications》1987,148(1):133-139
Seven fractions of GTP-binding proteins separated by gel filtration of an extract of epicotyls of Pisum sativum seedlings were partially characterized. Seven fractions of GTP-binding proteins tentatively designated GP1 to GP7 had the capacity to be ADP-ribosylated by pertussis toxin. Pooled fractions of GP2 to GP7 showed Km values 2, 20, 50, 10, 3 and 1 nM, respectively. The binding of [35S]GTP gamma S to GTP-binding proteins was prevented competitively in the presence of 0.1 mM GTP and also prevented in the presence of 0.1 mM ATP. Binding of [35S]GTP gamma S to the proteins produced a decrease in their molecular weights. 相似文献
996.
Mamoru Tsukuda Izumi Mochimatsu Miki Sakumoto Shigeru Furukawa Seiichiro Yuyama Shunsuke Yanoma Akira Kubota 《Biotherapy》1993,6(2):155-161
In order to select the most cytotoxic effector cells for adoptive immunotherapy, lymphokine activated killer (LAK) cells, tumor infiltrating lymphocytes (TILs) and autologous mixed lymphocyte tumor cell culture (MLTC) cells derived from peripheral blood mononuclear cells (PBMC) in the same subject with head and neck carcinomas were prepared. The autologous tumor cell killing activity and cell surface phenotypes of each of the three effector cells were studied. MLTC cells cultured with interleukin-2 (IL-2) showed the strongest cytotoxic activity among these three different effector cells. Although TILs had suppressed killing activity immediately after isolation, after successive cultivations with IL-2, a cytotoxic activity against autologous tumor cells stronger than that of LAK cells appeared. Both IL-2 stimulated MLTC cells and TILs showed an enrichment of CD8 positive and CDU negative cells in a CD3 positive subpopulation.Abbreviations CD
cluster differentiation
- IL-2
interleukin-2
- LA
lymphokine activated
- LAK
lymphokine activated killer
- MLTC
mixed lymphocyte tumor cell culture
- NK
natural killer
- PBMC
peripheral blood mononuclear cells
- TILs
tumor infiltrating lymphocytes 相似文献
997.
998.
Aberrant expression of microRNAs (miRNA) is associated with phenotypes of various cancers, including pancreatic cancer. However, the mechanism of the aberrant expression is largely unknown. Activation of the mitogen-activated protein kinase (MAPK) signaling pathway plays a crucial role in gene expression related to the malignant phenotype of pancreatic cancer. Hence, we studied the role of MAPK in the aberrant expression of miRNAs in pancreatic cancer cells. The alterations in expression of 183 miRNAs induced by activation or inactivation of MAPK were assayed in cultured pancreatic cancer cells and HEK293 cells by means of the quantitative real-time PCR method. We found that four miRNAs, namely, miR-7-3, miR-34a, miR-181d, and miR-193b, were preferentially associated with MAPK activity. Among these miRNAs, miR-7-3 was upregulated by active MAPK, whereas the others were downregulated. Promoter assays indicated that the promoter activities of the host genes of miR-7-3 and miR-34a were both downregulated by alteration in MAPK activity. Exogenous overexpression of the MAPK-associated miRNAs had the effect of inhibition of the proliferation of cultured pancreatic cancer cells; miR-193b was found to exhibit the most remarkable inhibition. A search for target genes of miR-193b led to identification of CCND1, NT5E, PLAU, STARD7, STMN1, and YWHAZ as the targets. Translational suppression of these genes by miR-193b was confirmed by reporter assay. These results indicate that activation of MAPK may play a significant role in aberrant expression of miRNAs and their associated phenotypes in pancreatic cancer. 相似文献
999.
Takahashi H Miller J Nozaki Y Takeda M Shah J Hase S Ikegami M Ehara Y Dinesh-Kumar SP;Sukamto 《The Plant journal : for cell and molecular biology》2002,32(5):655-667
The dominant locus, RCY1, in the Arabidopsis thaliana ecotype C24 confers resistance to the yellow strain of cucumber mosaic virus (CMV-Y). The RCY1 locus was mapped to a 150-kb region on chromosome 5. Sequence comparison of this region from C24 and a CMV-Y-susceptible C24 mutant predicts that the RCY1 gene encodes a 104-kDa CC-NBS-LRR-type protein. The RCY1 gene from C24, when expressed in the susceptible ecotype Wassilewskija (Ws), restricted the systemic spread of virus. RCY1 is allelic to the resistance genes RPP8 from the ecotype Landsberg erecta and HRT from the ecotype Dijon-17, which confer resistance to Peronospora parasitica biotype Emco5 and turnip crinkle virus (TCV), respectively. Examination of RCY1 plants defective in salicylic acid (SA), jasmonic acid (JA) and ethylene signaling revealed a requirement for SA and ethylene signaling in mounting a resistance response to CMV-Y. The RCY1 nahG etr1 double mutants exhibited an intermediate level of susceptibility to CMV-Y, compared to the resistant ecotype C24 and the susceptible ecotypes Columbia and Nossen. This suggests that in addition to SA and ethylene, a novel signaling mechanism is associated with the induction of resistance in CMV-Y-infected C24 plants. Moreover, our results suggest that the signaling pathways downstream of the RPP8, HRT, and RCY1 have evolved independently. 相似文献
1000.
Enhancement of tolerance to heavy metals and oxidative stress in Dunaliella tertiolecta by Zn-induced phytochelatin synthesis 总被引:5,自引:0,他引:5
Tsuji N Hirayanagi N Okada M Miyasaka H Hirata K Zenk MH Miyamoto K 《Biochemical and biophysical research communications》2002,293(1):653-659
The synthesis of phytochelatins (PCs) in a marine alga, Dunalliela tertiolecta, is strongly induced by Zn. Pretreatment of the cells with Zn enhances the tolerance toward toxic heavy metals such as Cd, Hg, Cu, Pb, and arsenate. Moreover, the pretreatment also increases the tolerance toward oxidative stress caused by hydrogen peroxide or paraquat. In vitro analysis shows that PC is a stronger scavenger of hydrogen peroxide and superoxide radical than glutathione. These results suggest that PCs inducibly synthesized by Zn treatment could play a role not only in detoxification of heavy metals but also in mitigation of oxidative stress. 相似文献