173 resultados para Mt. Everest


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The taxomic classification and phylogenetic relationships within the bear family remain argumentative subjects in recent years. Prior investigation has been concentrated on the application of different mitochondrial (mt) sequence data, herein we employ tw

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The pantherine lineage of the cat family Felidae (order: Carnivora) includes five big cats of genus Panthera and a great many midsized cats known worldwide. Presumably because of their recent and rapid radiation, the evolutionary relationship among pantherines remains ambiguous. We provide an independent assessment of the evolutionary history of pantherine lineage using two complete mitochondrial (mt) genes (ND2 and ND4) and the nuclear beta-fibrmogen intron 7 gene, whose utility in carnivoran phylogeny was first explored. The available four mt (ND5, cytb, 12S, and 16SrRNA) and two nuclear (IRBP and TTR) sequence loci were also combined to reconstruct phylogeny of 14 closely related cat species. Our analyses of combined mt data (six genes; approximate to 3750 bp) and combined mt and nuclear data (nine genes; approximate to 6500 bp) obtained identical tree topologies, which were well-resolved and strongly supported for almost all nodes. Monophyly of Panthera genus in pantherine lineage was confirmed and interspecific affinities within this genus revealed a novel branching pattern, with P. tigris diverging first in Panthera genus, followed by P. onca, P. leo, and last two sister species P. pardus and P. uncia. In addition, close association of Neofelis nebulosa to Panthera, the phylogenetic redefinition of Otocolobus manil within the domestic cat group, and the relatedness of Acinonyx jubatus and Puma concolor were all important findings in the resulting phylogenies. The potential utilities of nine different genes for phylogenetic resolution of closely related pantherine species were also evaluated, with special interest in that of the novel nuclear beta-fibrinogen intron 7. (c) 2005 Elsevier Inc. All rights reserved.

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Background: The Galliformes is a well-known and widely distributed Order in Aves. The phylogenetic relationships of galliform birds, especially the turkeys, grouse, chickens, quails, and pheasants, have been studied intensively, likely because of their close association with humans. Despite extensive studies, convergent morphological evolution and rapid radiation have resulted in conflicting hypotheses of phylogenetic relationships. Many internal nodes have remained ambiguous. Results: We analyzed the complete mitochondrial (mt) genomes from 34 galliform species, including 14 new mt genomes and 20 published mt genomes, and obtained a single, robust tree. Most of the internal branches were relatively short and the terminal branches long suggesting an ancient, rapid radiation. The Megapodiidae formed the sister group to all other galliforms, followed in sequence by the Cracidae, Odontophoridae and Numididae. The remaining clade included the Phasianidae, Tetraonidae and Meleagrididae. The genus Arborophila was the sister group of the remaining taxa followed by Polyplectron. This was followed by two major clades: ((((Gallus, Bambusicola) Francolinus) (Coturnix, Alectoris)) Pavo) and (((((((Chrysolophus, Phasianus) Lophura) Syrmaticus) Perdix) Pucrasia) (Meleagris, Bonasa)) ((Lophophorus, Tetraophasis) Tragopan))). Conclusions: The traditional hypothesis of monophyletic lineages of pheasants, partridges, peafowls and tragopans was not supported in this study. Mitogenomic analyses recovered robust phylogenetic relationships and suggested that the Galliformes formed a model group for the study of morphological and behavioral evolution.

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Specific interactions among biomolecules drive virtually all cellular functions and underlie phenotypic complexity and diversity. Biomolecules are not isolated particles, but are elements of integrated interaction networks, and play their roles through specific interactions. Simultaneous emergence or loss of multiple interacting partners is unlikely. If one of the interacting partners is lost, then what are the evolutionary consequences for the retained partner? Taking advantages of the availability of the large number of mammalian genome sequences and knowledge of phylogenetic relationships of the species, we examined the evolutionary fate of the motilin (MLN) hormone gene, after the pseudogenization of its specific receptor, MLN receptor (MLNR), on the rodent lineage. We speculate that the MLNR gene became a pseudogene before the divergence of the squirrel and other rodents about 75 mya. The evolutionary consequences for the MLN gene were diverse. While an intact open reading frame for the MLN gene, which appears functional, was preserved in the kangaroo rat, the MLN gene became inactivated independently on the lineages leading to the guinea pig and the common ancestor of the mouse and rat. Gain and loss of specific interactions among biomolecules through the birth and death of genes for biomolecules point to a general evolutionary dynamic: gene birth and death are widespread phenomena in genome evolution, at the genetic level; thus, once mutations arise, a stepwise process of elaboration and optimization ensues, which gradually integrates and orders mutations into a coherent pattern.

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The mitochondrial DNA (mtDNA) control region is believed to play an important biological role in mtDNA replication. Large deletions in this region are rarely found, but when they do occur they might be expected to interfere with the replication of the molecule, thus leading to a reduction of mtDNA copy number. During a survey for mtDNA sequence variations in 5,559 individuals from the general Chinese population and 2,538 individuals with medical disorders, we identified a 50-bp deletion (m.298_347del50) in the mtDNA control region in a member of a healthy Han Chinese family belonging to haplogroup B4c1b2, as suggested by complete mtDNA genome sequencing. This deletion removes the conserved sequence block II (CSBII; region 299-315) and the replication primer location (region 317-321). However, quantification of the mtDNA copy number in this subject showed a value within a range that was observed in 20 healthy subjects without the deletion. The deletion was detected in the hair samples of the maternal relatives of the subject and exhibited variable heteroplasmy. Our current observation, together with a recent report for a benign 154-bp deletion in the mtDNA control region, suggests that the control of mtDNA replication may be more complex than we had thought. Hum Mutat 31:538-543, 2010. (C) 2010 Wiley-Liss, Inc.

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本论文由2 个相对独立的部分组成: S-DABO 类衍生物体外抗HIV 活性及 其机制研究和AZT-氟喹喏酮类偶联物体外抗HIV-1 活性及其机制研究。 HIV 逆转录酶抑制剂一直是抗HIV 药物研发的热点。该类抑制剂靶定在病 毒复制周期早期,为HAART 疗法提供了很多新的药物组合。目前FDA 批准上 市的逆转录酶抑制剂虽然有很多,但由于较严重的毒副作用、HIV 病毒易变异、 耐药性的出现等问题还需要开发更多的新的逆转录酶抑制剂。本论文对23 个 S-DABO 类化合物和8 个AZT-氟喹喏酮类偶联物的体外抗HIV 活性进行检 测,并对其中活性较高的化合物进行靶点和机制研究。 23 个S-DABO 类化合物采用对C8166 细胞的毒性试验,对HIV-1ⅢB 诱导的 合胞体形成的抑制试验和对HIV-1ⅢB 急性感染的MT-4 细胞的保护试验进行抗 HIV-1 活性初步筛选。试验结果发现所有化合物均对多种HIV 宿主细胞毒性小, 其中22 个化合物具有抗HIV-1 活性,特别是化合物RZK-4 和RZK-5,其对 HIV-1ⅢB 诱导的合胞体形成的SI 值(Selective index)分别为>16666 和>38462; RZK-4 和RZK-5 对HIV-1ⅢB 急性感染的MT-4 细胞的保护的SI 值分别为2666.67 和2150.54,与相应的阳性对照药品NVP(Nevirapine)的SI 值相接近。以p24 抗原水平为指标,对其中20 个化合物的抗HIV-1 活性进行确证,发现这20 个 化合物均能抑制 HIV-1ⅢB p24 抗原的产生,其中RZK-4 和RZK-5 的EC50 值分 别为5.93 和5.74ng/ml,比相应的阳性对照药品NVP(Nevirapine)的EC50 值 要低(27.3ng/ml)。这些化合物对试验株HIV-1MN、临床分离株HIV-1KM018、非 核苷类抑制剂耐药株HIV-1ⅢB A17 也有较好的抑制效果。但这23 个S-DABO 类化合物对HIV-2 病毒株均无抑制作用。通过检测化合物对感染与未感染细胞的 融合的抑制、对HIV-1 逆转录酶和蛋白酶活性的抑制、对慢性感染H9 细胞 (H9/HIV-1ⅢB)中病毒复制的抑制等试验来探讨化合物的抗HIV-1 机制。结果 显示:有20 个化合物对HIV-1 蛋白酶(PR)有抑制作用,其中有17 个化合物 对HIV-1 逆转录酶(RT)有抑制作用;但所有化合物均不能抑制感染与未感染 细胞的融合,也不能抑制慢性感染H9 细胞中病毒的复制。试验结果表明,这 23 个S-DABO 类化合物主要通过抑制HIV-1 逆转录酶来发挥作用,它们是典型 的非核苷类RT 抑制剂。 8 个AZT-氟喹喏酮类偶联物采用对C8166 细胞的毒性试验,对HIV-1ⅢB 诱导的合胞体形成的抑制试验和对HIV-1ⅢB急性感染的MT-4 细胞的保护试验 进行抗HIV-1 活性初步筛选。试验结果发现其中2 个化合物SRLZ 和SROZ 有 较显著的抗HIV-1 活性,其对HIV-1ⅢB诱导的合胞体形成抑制的SI 值分别为 >41667 和>105263;对HIV-1ⅢB 急性感染的MT-4 细胞的保护的SI 值分别为 30162 和 6368,与AZT(Zidothymidine)的SI 值相近似。以p24 抗原水平为 指标,对其抗HIV-1活性进行确证,发现化合物SRLZ和SROZ均能抑制HIV-1ⅢB p24 抗原的产生,其EC50 值分别为 0.71 和2.1ng/ml,比相应的阳性对照药品AZT 的EC50 值要低(3.5ng/ml)。化合物SRLZ 和SROZ 对临床分离株HIV-1KM018 也有较好的抑制活性,其EC50 值分别为1.4 和22ng/ml。通过检测化合物对慢 性感染H9 细胞(H9/HIV-1ⅢB)中病毒复制的抑制试验来探讨化合物的抗HIV-1 机制,结果表明化合物SRLZ 和SROZ 均不能抑制慢性感染H9 细胞中病毒的 复制。通过检测化合物对金黄色葡萄球菌的抑制作用来检测其抗菌活性,化合 物SRLZ 和SROZ 对金黄色葡萄球菌有较好的抑制作用,其MIC(Minimum inhibitory concentration)值分别为14.65 和7.32μg/ml,与其相应的阳性对照药 物的MIC 值相类似。试验结果表明:药物—药物偶连这种化学修饰方法并没有 改变AZT-氟喹喏酮类偶联物的抗HIV 作用靶点,但也没有较大地影响到其体 外抗病毒活性和抗微生物活性。

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通过对人免疫缺陷病毒复制过程的抑制作用研究,探索光动力疗法(PDT)在艾滋病防治中的潜在价值。使 用不同稀释浓度的光敏剂血卟啉单甲醚(HMME)和亚甲蓝(MB)分别与人免疫缺陷病毒HIV一1Ⅲs或宿主细胞 MT4,C8166或H9/HIV-IⅢB孵育2 h。以波长630 nm能量密度0.3 J/cm2的半导体激光进行照射。继续孵育若干 小时后,用噻唑蓝(MTT)比色法检测细胞存活率或合胞体计数,同时收集培养上清液用ELISA法检测HIV-I p24 抗原。结果表明,光动力疗法能显著抑制人免疫缺陷病毒诱导的细胞一细胞融合(HMME-PDT抑制率64.68%, MB-PDT抑制率61.56%)和病毒一细胞融合(HMME—PDT抑制率85%,Mt}PDT抑制率73.64%),并对游离病毒 有很强的杀伤作用,最高可达到100%。光动力疗法不能抑制慢性感染期和急性感染2 h后病毒的复制过程。可 见光动力疗法对游离病毒和病毒感染诱导的膜融合有显著抑制作用,有可能为艾滋病的防治提供一种新的方法。

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This study investigated the 70% aqueous acetone extract of the fruits of Schisandra rubriflora which led to the isolation of eight lignans, including a new isolate, rubrisandrin C (1), and seven known lignans (2-8). The structure of 1 was established by extensive 1D and 2D NMR spectroscopy and its absolute stereochemistry was determined by CD spectrum. Compounds 1-5 and 7-8 were evaluated for their anti-HIV-1 activity that showed inhibitory activity on HIV-1(IIIB) induced syncytium formation with EC50 values in the range of 2.26 similar to 20.4 mu g/mL. Compounds 1 and 7 exerted their obvious protection of HIV-1(IIIB) inducted MT-4 host cells lytic effects with a selectivity index of 15.4 and 24.6, respectively.

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In the present study, we examined the effects of extremely low-frequency (ELF) electromagnetic fields on morphine-induced conditioned place preferences in rats. During the conditioning phase (12 days), three groups of rats were placed in a sensory cue-defined environment paired with morphine (10 mg/kg, i.p.) following exposure to either 20 Hz (1.80 mT) or 50 Hz (2.20 mT) or sham electromagnetic fields for 60 min/day, respectively, and were placed in another sensory cue-defined environment paired with physiological saline (1 ml/kg, i.p.) without exposure to electromagnetic fields. After finishing 12 days of conditioning, preference tests for the morphine-paired place were performed during a 10-day withdrawal period. The exposure to electromagnetic fields substantially potentiated morphine-induced place preferences in rodents, suggesting that ELF electromagnetic fields can increase the propensity for morphine-induced conditioned behaviors. (C) 2005 Elsevier Ireland Ltd. All rights reserved.

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We investigated memory impairment in newly hatched chicks following in ovo exposure to a 50-Hz magnetic field (MF) of 2 mT (60 min/day) on embryonic days 12-18. Isolated and paired chicks were used to test the effect of stress during training, and memory retention was tested at 10, 30, and 120 min, following exposure to a bitter-tasting bead (100% methylanthranilate). Results showed that memory was intact at 10 min in both isolated and paired chicks with or without MF exposure. However, while isolated chicks had good memory retention levels at 30 and 120 min, those exposed to MF did not. The results suggest a potential disruption of memory formation following in ovo exposure to MF, with this effect only evident in the more stressed, isolated chicks. Bioelectromagnetics 31:150-155, 2010. (C) 2009 Wiley-Liss. Inc.

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从超数排卵的14只母兔获得438枚受精卵, 卵龄16-22h。显微操作在带微分干涉和相差的Nikon倒置显微镜下进行。注射针的尖端外径0.5#mu#m, 离尖端40和80#mu#m处的外径分别为4.2和6.5#mu#m。注射用外源基因是绵羊生长激素基因与MT-1启动基因藕连的线状DNA溶液(1ng/#mu#l)。140枚注射的受精卵和未注射的145枚受精卵(对照), 在Ham^sF-10培养液(补充生长因子)中培养(38℃, 5%的CO_(2))。结果培养48h后, 注射组卵裂发育率分别是: 未卵裂7.9%(11/140)、卵裂至2-4细胞期11.0%(16/140)、卵裂至8-16细胞期80.7%(113/140)。对照组相应的卵裂率分别是4.1%(6/145)、12.4%(18/145)和83.4%(121/145)。两组卵裂发育率相近。

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球果蝠Sphaerias blanfordi(Thomas,1891)是亚洲南部喜马拉雅-印度支那地区的特有种,甚为罕见而少有报道.曾被认为是单型种,几乎无雄性特征的描述.蔡桂全和张遁治(1980)根据采自西藏东南部墨脱的2只雄性标本订了一亚种一墨脱亚种Sphaerias blanfordi motuoensis,其主要特征是颈下侧有一对灰黄色的圆形毛斑.中国科学院昆明动物研究所先后在云南西北部高黎贡山地区采获25号标本(9♂♂,16♀♀),发现球果蝠两性在外形上有明显的性别差异,雄性的颈下侧有一对圆形、灰黄色的刷状毛斑,但雌性均无;对比墨脱标本,认为墨脱亚种的鉴别特征不可靠,亚种不能成立.Lunde(2003)曾报道采自越南北部Mt.Tay Con Linh Ⅱ地区的43号标本,其前臂长和上犬齿外宽明显与印度、缅甸和云南西北部高黎贡山地区的标本不同,可能是真正的地理亚种.

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据2003年9月至2005年9月,对云南中部无量山大寨子黑长臂猿种群(5个群体)进行了观察,获得了群体大小、配偶体制、繁殖间隔、环境容纳量、死亡率、灾害的发生频率等种群参数,并结合近缘种的一些相关数据,利用旋涡模型(Vortex 914),对无量山大寨子地区黑长臂猿亚种群的动态进行了模拟分析.结果显示:大寨子亚种群是一个具有很强的潜在繁殖力的种群,如果没有偷猎,亚种群在100a之内不会灭绝,并且能迅速达到环境容纳量.但是每年如果有1只成年雄性和1只成年雌性被猎杀,该种群将会在第78年灭绝,且灭绝概率为100%.不同程度的死亡率对种群影响不大,但高死亡率显著延缓了种群到达环境容纳量的时间.环境容纳量对种群遗传多样性损失具有重要的影响,在没有猎杀的情况下,种群的长期存活需要一个较大的环境容纳量.因此,在黑长臂猿受到严格保护、且栖息地主要在保护区内的今天,严密监控火灾的发生,限制牲畜进入林区等人为干扰的影响,保护好黑长臂猿栖息地是首要工作之一.但如果能使其栖息地周围的森林植被得到恢复,增加其栖息范围,将有利于该地区黑长臂猿的发展.

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无量山是黑长臂猿景东亚种的唯一分布区,现栖息着98群500余只黑长臂猿。长臂猿是典型的树栖性灵长类动物,通过对无量山西坡大寨子地区250个样方的调查,分析了随海拔梯度升高,黑长臂猿栖息地植被乔木层物种多样性和结构的变化情况。共记录乔木111种,隶属于33科;木质藤本23种,隶属于18科。其中优势科主要有樟科(Lauraceae)、木兰科(Magnoliaceae)、壳斗科(Fagaceae)、山茶科(Theaceae)和杜鹃花科(Ericaceae)。根据不同海拔乔木层物种组成的差异,该区可划分为半湿润常绿阔叶林(2100~2300m)和中山湿性常绿阔叶林(2400~2600m)两种植被类型。多样性指数(Shannon-Wiener指数)随海拔升高在两种植被类型中均呈下降趋势;均匀度指数(Pielou指数)在半湿润常绿阔叶林中呈下降趋势,在中山湿性常绿阔叶林中无明显变化。半湿润常绿阔叶林中,阳坡的乔木物种多样性低于阴坡;而阳坡物种多样性在两种植被类型间差异显著。随着海拔的升高,乔木层的平均高度和上层乔木(Ⅰ层)的比例均逐渐降低,但下层乔木却呈上升趋势。6种优势乔木树种的种群年龄结构分析表明,该区植被的乔木层呈...

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We tested the intergroup spacing hypothesis with a 13-month field study of the interaction of singing behaviour between 3 neighbouring groups of black-crested gibbons (Nomascus concolor jingdongensis) at Mt. Wuliang, Central Yunnan, China. Neighbouring gr