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1.
A new species, Galearis huanglongensis Q.W.Meng & Y.B.Luo, is described and illustrated. It is similar to Galearis cyclochila (Franch. & Sav.) Soó and Galearis diantha (Schltr.) P.F.Hunt, but differs in having a short spur, two elliptical lateral stigma lobes and distinctly separated bursicles. This new species is known only from the type locality, the Huanglong Valley, Songpan County, western Sichuan, China, growing amongst mosses under alpine shrubs at an elevation of about 3000 m. Based on two years of observations of its population size, the species was categorized as critically endangered CR (B1a, B2a) according to the World Conservation Union (IUCN) Red List Categories and Criteria, Version 3.1. The micromorphology of pollinia and seeds was observed by scanning electron microscopy and compared with that of G. cyclochila and G. diantha. The results supported G. huanglongensis Q.W.Meng & Y.B.Luo as a new species. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 158 , 689–695.  相似文献   
2.
Lactic acid produced from the cells is a potential cause of extra- and intracellular acidification. Due to scarce technical tools, lactic acid that leads to acidification could not be reduced and direct evidence of the relationship between metabolic lactate and apoptosis has not yet been elucidated. In this study, we designed a cellular pH regulation system in CHO cells by a reduction of lactate dehydrogenase (LDH) activity through LDH antisense mRNA expression. This inhibited lactate production and, therefore, acidification of the cytosol. Under HCO3(-)-buffered growth conditions, both the parent CHO cells and the engineered CHO cells maintained their extracellular pH and intracellular pH fairly well. However, upon acidification of the cytosol, only the parent CHO cells underwent apoptosis under HCO3(-)-free conditions. In fact, we observed a number of apoptosis-related events only in control cells, including mitochondrial dysfunction, cytochrome c release, and an increase in caspase-3 enzymatic activity.  相似文献   
3.
渗透胁迫对高粱根K~+吸收的影响   总被引:4,自引:0,他引:4  
以CaSO40.5mmolL-1溶液培养高粱得到低钾植株,在渗透胁迫下当PEG-1000使外界渗透势下降时,刺激了高粱根高K+亲和系统的净K+积累,其表观Km值和Tmax值分别为18μmolL-1和49.6μmolg-1DWh-1。此高亲和系统不受可渗物质乙二醇和外界pH变化的影响,为蛋白质合成抑制剂环己酰亚胺抑制。  相似文献   
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Leucocytosis was shown to occur in the pulmonate gastropod Biomphalaria glabrata exposed to the trematode Echinostoma lindoense. In these sensitized snails, the leukocyte count in the hemolymph was elevated 3 to 5 days postexposure to miracidia, and prior to complete encapsulation of sporocysts. This increase continued 1 to 5 days after destruction of sensitizing, irradiated E. lindoense sporocysts. Counts returned to normal levels after this period. A significant and more rapid increase in numbers of circulating leukocytes occurred 1 to 6 hr after reexposure of snails to a sensitizing dose of nonirradiated E. lindoense sporocysts. The leukocyte counts usually returned to normal levels after this period, except in snails in which some resensitizing sporocysts remained alive.  相似文献   
6.
黄甜  郭青海  邹凯  李达维  易海军 《生态学报》2021,41(19):7579-7588
乡村社会-生态系统的稳定和可持续发展为农业农村现代化的实现奠定着基础,在稳定社会经济发展、提高城乡居民福祉方面发挥着重要作用。服务性公共设施作为乡村社会-生态系统供给服务的重要组成部分,代表了乡村的发展水平与该地区居民生活质量水平。研究公共服务设施的空间分布特征和综合评价其供给服务可改善乡村社会-生态系统结构,为城乡居民提供高质量的社会生态系统服务。以厦门市岛外城市化乡村为研究对象,通过厦门市岛外POI数据和乡村社会经济统计数据,以公共服务设施为景感载体,分析其空间分布和测度其供给服务水平,采用核密度分析方法与熵值分析法,分析厦门市乡村社会-生态系统供给服务空间分布特征,结合人口、经济、距岛内核心区距离等指标对各村庄社会-生态系统供给服务能力进行皮尔逊相关性分析。研究发现厦门乡村公共设施供给服务能力表现为集美区 > 海沧区 > 同安区 > 翔安区;各村庄公共设施供给服务能力水平影响因素是多元且具有多样性的;提出从城乡居民的认知心理与物质需求出发对公共设施进行景感生态营造以提高村庄社会-生态系统供给服务能力,更好满足人们的需求。本文对公共服务设施的空间优化提出对策建议,研究结果可为乡村社会-生态系统供给服务提升和乡村可持续发展提供理论研究依据。  相似文献   
7.
高原湖泊流域是高原地区人类活动的重要载体,兼具高生态价值和高脆弱性的特点。随着高原湖泊流域城市化和工业化发展加速,湖泊面积萎缩,污染加剧,流域生态环境受损严重,引发了一系列生态环境问题,如水土流失、水污染、湿地退化、生境质量下降等。亟需开展生态修复以平衡经济发展与生态环境保护之间关系,而基于整体保护与系统治理思维诊断并修复生态修复优先区,是科学有序推进国土空间生态保护与修复的重要抓手。基于此,研究以高原湖泊流域典型代表滇池流域为例,利用人类足迹和景观生态风险模型定量评估生态系统所受负向干扰,以最小累积阻力模型和电路理论构建流域生态网络;提取生态网络受负向干扰较高的关键区域为生态修复优先区并提出针对性修复措施。研究表明:(1)滇池流域人类干扰和生态风险整体较高,人类干扰整体呈核心—边缘递减的圈层式分布,中高生态风险占据了绝大部分区域。人类交通网络大幅扩展了人类干扰和生态风险的强度和深度;(2)区域生态网络呈典型湖泊生态网络特点,38条生态廊道呈放射状或环状分布,连通湖区、山区两大生态空间内共23块生态源地,保障区域生态安全;(3)研究共提取生态源地修复优先区73.83km2  相似文献   
8.
ObjectiveThe objective of this study was to determine whether dietary black soldier fly (Hermetia illucens, HI) larvae oil (HILO) could serve as an alternative fat source to soybean oil (SBO) in laying hen diets.MethodsWe randomly assigned 25-week-old Hy-line Brown laying hens (n = 144) to receive (n = 6 hens/group; eight replicates) a control or an experimental diet in which SBO was replaced with 50% (50HILO) or 100% HILO (100HILO).ResultsDietary HILO did not negatively affect body weight or productive performance during the study. The eggs also had similar quality parameters, proximate composition, and cholesterol levels. However, the yolk color index was significantly higher (p<0.01) in the 100HILO than in the other groups. Dietary HILO significantly altered the composition of fatty acids (FAs) in abdominal fat and eggs. Total saturated fatty acids (SFAs) and total polyunsaturated FAs (PUFAs) were significantly increased and decreased in the 50HILO and 100HILO groups, respectively, compared with those in the control group (p<0.001 and p<0.0001, respectively). Specifically, the medium-chain FAs lauric and myristic acids were remarkably increased in the abdominal fat of laying hens fed HILO (p<0.0001), whereas only myristic acid increased in eggs (p<0.0001). Undesirable heavy metal (aluminum, fluorine, arsenic, lead, mercury, and cadmium) concentrations were below permissible limits in eggs.ConclusionWe considered that HILO could be an alternative dietary fat to SBO for laying hens with maintained productive performance and good egg quality.  相似文献   
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The conditions for induction of B-cell inducing factor (BIF) by human peripheral blood T cells was investigated. BIF was assayed by induction of immunoglobulin secreting cells (ISC) in peripheral blood B (non-T) cells stimulated with Staphylococcus aureus bacteria strain Cowan I (Sac), and in the IgM cell line SKW6.4. Maximum BIF production occurred with high concentrations of the T-cell mitogens phytohemagglutinin, concanavalin A, and PWM. Dexamethasone (Dex) also induced BIF production in T cells at 10(-5) to 10(-7) M. At 10(-5) and 10(-6) M Dex, the T-cell supernatants had to be dialyzed before testing because Dex alone stimulated variable levels of ISC in both test B-cell assays. Dex did not enhance BIF production by T cells that were optimally stimulated by lectin. BIF levels were maximum by Day 2 of T-cell cultures and remained high at Days 3 and 4. In contrast, IL-2 reached a peak at Day 1 and declined drastically by Day 4. We previously showed that IL-2 at less than 100 U/ml did not induce ISC in B cells and did not alter ISC induction by BIF. Dex did not induce IL-2 production and inhibited IL-2 production induced by Con A, in contrast to the promoting effects of Dex on BIF production, providing further evidence for the independence of BIF and IL-2 production and B-cell stimulation.  相似文献   
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