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Since the beginning of the 1980s, the Paramecium–Holospora system has become an important model and a subject of international scientific cooperation in symbiosis studies, established by Prof. H.-D. Görtz. In the article, a brief sketch of the scientist's life, his areas of interest, expertise and his contribution to our knowledge of protozoan symbiosis are discussed.  相似文献   

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Water strider Aquarius paludum (Fabricius) is a cosmopolitan species colonizes mainly freshwater but occasionally brackish habitats throughout the Palearctic and Oriental regions. Water strider Gerris latiabdominis (Miyamoto) is a common species in Japan lives in temporary habitats as freshwater paddy fields. These two species often occur syntopically. We investigated differences in the developmental response to brackish water during embryonic and larval stages between the two species. Eggs were exposed to 0–1.8% NaCl solutions within 24 h of oviposition. Larvae of G. latiabdominis were exposed to salinities of 0, 0.5%, and 0.9% from the first instar until adult emergence. Limits of NaCl concentration for hatching were 1.3% and 1.0% for A. paludum and G. latiabdominis, respectively. The hatching rate of G. latiabdominis was lower than that of A. paludum at salinities ≥0.9%. The period of embryonic development of G. latiabdominis was more prolonged than that of A. paludum at a given salinity. Although the salinity tolerance of G. latiabdominis was lower than that of A. paludum, our results suggest G. latiabdominis has the physiological capacity to expand into brackish waters. High and low salinity tolerances of A. paludum and G. latiabdominis, respectively, reflect the relatively wide range of habitat salinities utilized by A. paludum and the relatively restricted habitats preferred by G. latiabdominis. The high salinity tolerance of A. paludum could be an important factor contributing to their cosmopolitan distribution because high tolerance to salinity means the possibility of them to be dispersed via ocean or sea to other continents and islands.  相似文献   

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Diverse and extensive macrofouling of the left-hand (eyed) side has been observed in multiple films and photographs of different specimens of Eckström's topknot Zeugopterus regius. Identified foulers include macroalgae and tunicates. Photographs of unfouled specimens and preserved juveniles have also been inspected. Macrofouling is not universal in this species; unfouled fish were observed around the strongly tidal British Isles, whereas the worst-fouled topknots were seen in the eutrophic, microtidal northern Adriatic.  相似文献   

5.
Biopsies from different segments of the pregnant human uterus were superfused in organ chambers and contractile activity was registered. Leukotriene C4(LTC4) caused inhibition of spontaneous but not noradrenaline induced contractile activity in strips from the cervix. This effect occured both in early pregnancy and at term. However, the lower and the upper uterine segment of the term pregnant uterus did not respond to LTC4. The results represent a documentation of the segmental differentiation in the uterine response to eicosanoids.  相似文献   

6.
The effect of taurine on Ca2+ binding and uptake was studied with rabbit brain cortical and hippocampal synaptosomes. Taurine (25 mM) increased by 25% the high affinity 45Ca2+ binding in the cortical fraction and by 55% in hippocampal synaptosomes but had no effect on low affinity Ca2+ binding. Taurine decreased significantly the fluorescence of the chlorotetracycline-hydrophobic Ca2+ chelate probe in both synaptosomal fractions which suggests a shift of bound Ca2+ from the hydrophobic to the hydrophilic part of the membranes. The uptake of 45Ca2+ by rabbit brain synaptosomes, when measured in control and 65 mK K+-containing media, was not influenced by taurine. However, taurine inhibited significantly the 45Ca2+ uptake in synaptosomes incubated in media containing moderately increased K+ concentrations (14 and 20 mM K+). The effects of taurine are discussed in conjunction with its stabilizing effect on excitable membranes.  相似文献   

7.
A Nagy  L Gráf  A Lajtha 《Life sciences》1983,33(9):835-840
Using synaptosomal rat brain membranes, the degradation of Met-enkephalin in both free and receptor-bound form was measured, together with the dissociation of Met-enkephalin from the receptors. The results show that the degradation rate of initially receptor-bound Met-enkephalin is significantly smaller than either the rate of dissociation from the receptors or that of the degradation of free Met-enkephalin. These data suggest that intact Met-enkephalin dissociates from the receptors and then it becomes a target for the same membrane-associated peptidases that split free Met-enkephalin. This view is supported by the good fitness of the measured degradation of initially receptor-bound Met-enkephalin to the predicted degradation curve calculated from the dissociation rate of receptor-bound Met-enkephalin and the degradation rate of free Met-enkephalin.  相似文献   

8.
PURPOSE: To evaluate whether contrast enhancement on cone-beam breast-CT (CBBCT) could aid in discrimination of breast cancer subtypes and receptor status. METHODS: This study included female patients age >40 years with malignant breast lesions identified on contrast-enhanced CBBCT. Contrast enhancement of malignant breast lesions was standardized to breast fat tissue contrast enhancement. All breast lesions were approved via image-guided biopsy or surgery. Immunohistochemical staining was conducted for expression of estrogen (ER), progesterone (PR), human epidermal growth factor receptor-2 (HER2) and Ki-67 index. Contrast enhancement of breast lesions was correlated with immunohistochemical breast cancer subtypes (Luminal A, Luminal B, HER2 positive, triple negative), receptor status and Ki-67 expression. RESULTS: Highest contrast enhancement was seen for Luminal A lesions (93.6 HU) compared to Luminal B lesions (47.6 HU, P = .002), HER2 positive lesions (83.5 HU, P = .359) and triple negative lesions (45.3 HU, P = .005). Contrast enhancement of HER2 positive lesions was higher than Luminal B lesions (P = .044) and triple negative lesions (P = .039). No significant difference was evident between Luminal B and triple negative lesions (P = .439). Lesions with high Ki-67 index showed lower contrast enhancement than those with low Ki-67 index (P = .0043). ER, PR and HER2 positive lesions demonstrated higher contrast enhancement than their receptor negative counterparts, although differences did not reach statistical significance (P = .1714; P = .3603; P = .2166). CONCLUSIONS: Contrast enhancement of malignant breast lesions on CBBCT correlates with immunohistochemical subtype and proliferative potential. Thereby, CBBCT might aid in selecting individualized treatment strategies for breast cancer patients based on pre-operative imaging.  相似文献   

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When the nests of marine turtles are at a risk of inundation, relocation of the nests are often used in the conservation measures. Here, I determined the effect of nest relocation on Loggerhead Turtle (Caretta caretta) egg hatching success during the 2013 and 2014 nesting seasons in the Göksu Delta, Mersin, Turkey. I compared natural and relocated clutches, including those relocated before and after inundation, and evaluated 102 (94.6%) and 63 (81.1%) of survived nests in 2013 and 2014 respectively. Relocated nests experienced a 30% decrease in hatching success and a more prolonged incubation period compared to nests left in situ. Egg failure in nests relocated before and after inundation was similar in early-stage embryos, whereas it was three-fold higher in mid-stage embryos and two-fold lower in late-stage embryos. Thus, there was no significant difference in overall hatching success between the two relocation types. Moreover, there was no effect of delayed relocation of nests after inundation on hatching success. Possible impacts specific to the nesting site should be considered and explored before using nest relocation as a conservation tool. The relocation approach is recommended for nests at a high risk of inundation when the loss of nests is inevitable.  相似文献   

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摘要 目的:探讨白细胞介素(Interleukin-33,IL-33)可能通过调控上皮细胞黏附分子(Epithelial cell adhesion molecule, EpCAM)表达参与干燥综合征(Sj?gren''s syndrome, SS)发病的作用机制。方法:收集因SS诊断需要行唇腺活检术的患者血清和唇腺组织标本及相关临床资料,根据2016年ACR-EULAR SS分类诊断标准将患者分为SS组和非SS组,选取性别、年龄匹配的21例SS患者和21例非SS患者,利用多重检测流式试剂盒(人炎症因子组合1)检测血清中IL-33水平并用t检验比较SS患者组与非SS患者组、抗SSA抗体阳性与阴性组以及唇腺病理阳性与阴性组之间IL-33水平的差异。对唇腺组织石蜡切片进行IL-33免疫组织化学染色,用流式细胞术检测新鲜唇腺组织中上皮细胞EpCAM表达水平并与血清IL-33水平进行相关性分析。结果:SS患者组IL-33水平为(1736±590.1,n=21, pg/mL),显著高于非SS患者组(306.8±120.3, n=21, pg/mL)(t=2.373,P=0.027);唇腺病理阳性组即灶性血清IL-33水平(489.8±170, n=27, pg/mL)高于病理阴性组(1978±793.1, n=15, pg/mL),2组之间有统计学差异(t=2.368,P=0.023);而抗SSA抗体阳性组与阴性组之间无明显差异(P>0.05)。免疫组化染色结果提示SS患者唇腺组织上皮细胞IL-33表达相较于非SS患者上升,且血清IL-33水平与唇腺上皮细胞EpCAM的表达呈中等强度正相关(r=0.4915,P=0.0009,95%CI 0.2205-0.692)。结论:IL-33是与SS密切相关的炎症因子,IL-33可能通过促进唾液腺上皮细胞EpCAM的表达参与SS发病。  相似文献   

11.
郭慧文  严力蛟 《生态学报》2016,36(14):4288-4297
综合应用城市发展指数(CDI)和生态足迹(EF)指标,分析各直辖市1978—2012年的可持续发展情况,衡量发展方式由资源消耗型向环境友好型转变的程度。研究表明:各直辖市的CDI不断增长,至2012年均达到80左右,基本处于同一层次水平,城市经济社会发展状况总体良好。EF的动态变化呈现阶段性发展的特点,各直辖市间也存在显著差异,除上海市,其他3个直辖市的EF呈现增长态势,至2012年,北京EF最高(2.60 hm2/人),重庆最低(1.79 hm~2/人),是唯一一个低于全国平均EF的直辖市。综合分析CDI和EF,在相似的社会经济发展水平下,重庆市的资源消耗较低,可持续发展潜力较大;天津市一直处于资源消耗型发展中,亟待转型;近十年来,上海和北京的城市建设模式出现了一定转变,由以消耗环境资源为代价的发展模式转变为环境友好型的发展模式。  相似文献   

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ABSTRACT

The objective of this study was to estimate the sulphur amino acid (methionine + cystine) requirements and nitrogen endogenous losses in kittens aged 150 to 240 d. Thirty-six cats were distributed in six treatments (six cats per treatment) consisting of different concentrations of methionine + cystine (M + C): T1, 6.5 g/kg; T2, 8.8 g/kg; T3, 11.3 g/kg; T4, 13.6 g/kg; T5, 16.0 g/kg; and control, 6.5 g/kg. Diets were formulated by serial dilution of T5 (a diet relatively deficient in M + C but containing high protein concentrations) with a minimal nitrogen diet (MND). Thus, crude protein and amino acid concentrations in diets T1–T5 decreased by the same factor. The control diet was the T1 diet supplemented with adequate concentrations of M + C (6.5 g/kg; 8.8 g/kg; 11.3 g/kg; 13.6 g/kg and 16.0 g/kg). All diets were based on ingredients commonly used in extruded cat diets. Digestibility assays were performed for the determination of nitrogen balance. Nitrogen intake (NI) and nitrogen excretion (NEX) results data were fitted with an exponential equation to estimate nitrogen maintenance requirement (NMR), theoretical maximum for daily nitrogen retention (NRmaxT), and protein quality (b). M + C requirements were calculated from the limiting amino acid intake (LAAI) equation assuming a nitrogen retention of 45 to 65% NRmaxT. The NMR of kittens aged 150, 195, and 240 d was estimated at 595, 559, and 455 mg/kg body weight (BW)0.67 per day, respectively, and M + C requirements were estimated at 517, 664, and 301 mg/kg BW0.67 per day, respectively.  相似文献   

13.
In this study, the explanations of two classes of 10-year old children about what happens to the food that they eat were explored, particularly in the context of theories about the development of children's concepts of the human body. These ideas were investigated in a number of ways: obtaining children's own writing and drawings; semi-structured individual interviews; and examining choices made between alternative explanations. The results suggested that children applied their knowledge of everyday materials to understand the initial stages of what happens to food, but their ideas about later stages were more tentative and within the group there was a range of different kinds of explanation preferred. The limitations and achievements of the children's thinking are considered in the context of the school curriculum.  相似文献   

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The major form of bovine erythrocyte carbonic anhydrase has been prepared by a new method in which the conventional chloroform-ethanol treatment is replaced by chromatography on DEAE-Sephadex. Single crystals, suitable for high resolution X-ray diffraction studies, have been obtained from enzyme prepared by this method. The space group is P6122. The unit cell contains 12 enzyme molecules and has the dimensions a = b = 68 A?, c = 244 A?.  相似文献   

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The present study provided a two-years assessment to understand the seasonal fluctuations of aggregation of the Sandbar Shark, Carcharhinus plumbeus, in Boncuk Cove in the southern Aegean Sea. Underwater Visual Censuses (UVC) revealed that the species is present in the cove throughout the year but form aggregations only between March and November. Aggregation in groups was observed at a daily sea temperature above 18.1°C and this indicated a possible lower threshold for aggregations for Boncuk Cove population.  相似文献   

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Oxidative phosphorylation and glycolysis are important features, by which cells could bypass oxidative stress. The level of oxidative stress, and the ability of cells to promote oxidative phosphorylation or glycolysis, significantly determined proliferation or cell demise. In the present work, we have employed selective mitochondrial probe MitoTracker? Orange CMTM/Ros (MTO) to estimate the level of oxidative stress in cancer cells at different stressed conditions. MTO is partially sensitive to decrease of mitochondrial membrane potential and to reactive oxygen species (ROS) generated in mitochondria. We have demonstrated, that fluorescence lifetime of MTO is much more sensitive to oxidative stress than intensity-based approaches. This method was validated in different cancer cell lines. Our approach revealed, at relatively low ROS levels, that Gö 6976, a protein kinase C (PKC) α inhibitor, and rottlerin, an indirect PKCδ inhibitor, increased mitochondrial ROS level in glioma cell. Their involvement in oxidative phosphorylation and apoptosis was investigated with oxygen consumption rate estimation, western blot and flow-cytometric analysis. Our study brings new insight to identify feeble differences in ROS production in living cells.  相似文献   

17.
南方大口鲇幼鱼发育的初步研究   总被引:24,自引:5,他引:24       下载免费PDF全文
南方大口鲇的人工孵化鱼苗在11日龄时卵黄消失,转入营外生性营养的仔鱼阶段;23—26日龄仔鱼的主要外部器官分化完毕,转入稚鱼阶段;40—43日龄稚鱼除存在第二下颌须外,其余外形特征与成鱼相似,稚鱼阶段结束. 5月上旬在嘉陵江中采获到的当年幼鱼已发育到稚鱼阶段结束时期的水平;6—7月的当年幼鱼,当体长为151—177毫米时,第二下颌须消失.当年幼鱼体重和体长的关系为: W=e-10.87062L2.74257(N=77,r=0.9952)根据尾形、体色和须的数量的差异,可以区别南方大口鲇和鲇的当年幼鱼.  相似文献   

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《L'Anthropologie》2021,125(2):102887
Most of the animal figures on the T-shaped pillars at Göbekli Tepe seem to be depicted as the result of a realistic perspective. It may be related to the realist view that the animals subject of artificial being found in this area or even some of them play an important role in terms of food supply. The pillar itself, which hosts various animal figures, serves this purpose by taking on the function of being an animal's natural environment. On the other hand, the break from realism, which accompanies the point of view of the realist in animal depictions, is quite remarkable. This situation can be understood especially from rapprochements of the animals on the pillars whose relation is impossible in daily life. Furthermore, Göbekli Tepe's artist moves away from the realistic aspect by the size of animals depicted. If depicted animals were related to a mythical narrative, it can be assumed that the artist prefers a style that moves away from realism or realism according to the content of the narrative.  相似文献   

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Two colour polymorphic spittlebug species, Philaenus spumarius and Philaenus signatus were recorded for the first time in Gökçeada, Turkey. Three non-melanic – POP (populi), TYP (typicus), and VIT (vittata) – and three melanic MAR – (marginellus), FLA (flavicollis), and LCE (leucocephalus) – colour/pattern phenotypes of P. signatus were found. Philaenus spumarius was represented only by POP and TYP, which are expressed by a single pigmentation allele. The other six alleles were absent on this island, although they are found in most populations throughout the world. Stochastic events such as random genetic drift may be the reason for shaping the polymorphism of these two sympatric species in Gökçeada. Thus, the absence of pigmentation alleles possibly indicates the founder effect.  相似文献   

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