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All crocodilians are under varying degrees of threat due to over exploitation and these species have been listed in Appendix
I or II of CITES. The lack of molecular techniques for the identification of confiscated samples makes it difficult to enforce
the law. Conclusive forensic identification of species requires a complete gene sequence which is difficult in case of degraded
samples. We have developed two novel sets of primers to amplify two partial cytochrome b gene sequences of six crocodile species i.e. Crocodylus palustris, Crocodylus porosus, Crocodylus siamensis, Crocodylus niloticus, Gavialis gangeticus and Caiman crocodilus. These partial sequences were edited to give a complete cyt b gene sequence, which can be used as an effective tool for forensic authentication of crocodile species. A phylogeny of crocodile
species was reconstructed using these sequences. The described primers hold great promise in forensic identification of crocodile
species, which can aid in the effective enforcement of law and conservation of these ancient species. 相似文献
3.
Michal Grzmil Brian A. Hemmings 《Biochimica et Biophysica Acta - Proteins and Proteomics》2013,1834(7):1371-1380
Glioblastoma is the most common and aggressive brain tumor type, with a mean patient survival of approximately 1 year. Many previous analyses of the glioma kinome have identified key deregulated pathways that converge and activate mammalian target of rapamycin (mTOR). Following the identification and characterization of mTOR-promoting activity in gliomagenesis, data from preclinical studies suggested the targeting of mTOR by rapamycin or its analogs (rapalogs) as a promising therapeutic approach. However, clinical trials with rapalogs have shown very limited efficacy on glioma due to the development of resistance mechanisms. Analysis of rapalog-insensitive glioma cells has revealed increased activity of growth and survival pathways compensating for mTOR inhibition by rapalogs that are suitable for therapeutic intervention. In addition, recently developed mTOR inhibitors show high anti-glioma activity. In this review, we recapitulate the regulation of mTOR signaling and its involvement in gliomagenesis, discuss mechanisms resulting in resistance to rapalogs, and speculate on strategies to overcome resistance. This article is part of a Special Issue entitled: Inhibitors of Protein Kinases (2012). 相似文献
4.
报道寄生于北京猛禽的2种旋尾类线虫,其中一种为新种,另一种为中国新纪录种。作者分别对其做了光镜和电镜观察。北京副旋翼线虫,新种Paraspiralatus beijingensis sp.nov.采自于雕鸮的口腔和胃内,它与P. sakeri Gibbons,Nicholls &Bailey,2004的不同之处在于具有单个的肛前乳突,右交合刺远末端弯向背侧并稍微膨大而P. sakeri的交合刺远末端是直的,不膨大,呈钝尖形。纵纹腹小鸮无肛线虫Aprocta noctuae Spaul,1928采自红角鸮的体腔。本次所观察标本在形态上,如交合刺的长短和形状,尾乳突的数目和排列,阴门的位置,卵的大小等,都与前人对A. noctuae的描述一致。但是电子扫描电镜结果显示,A. noctuae的头端具有8个头乳突而不是4个,线虫角质层具有精细的横纹。A. noctuae为我国新纪录种。标本保存于河北师范大学生命科学学院。 相似文献
5.
Given the limited resources available for conservation, it is important that the areas to preserve are selected in a cost effective manner. However, the cost effectiveness of the surrogate species strategy (the use of information on one or more species to identify areas of value for other species for which there is no, or more limited, available information) has seldom been evaluated.In this study, we investigate the opportunity cost of setting aside breeding sites of two forest raptor species (the surrogate species) by evaluating their individual and combined contribution to preserve diversity of polypores (wood-decaying fungi) and birds against the contributions of previously established nature reserves. We use numeric optimization models to compare different reserve selection strategies.Site selection based on nest sites of the dominant raptor species was more cost-effective than strategies using sites of the subordinate species or those processes previously used to select nature reserves in Finland. The inclusion of both raptor species in the reserve selection model further improved its performance relative to other approaches. This indicates that the means by which Finnish reserves are selected could be enhanced by including the breeding sites of these, and maybe other species, among the criteria used to select reserves in the future.These results show that information on charismatic and well-surveyed species could be a cost-efficient add-on to help enhance conservation endeavours. Where there is inter-specific competition for biodiverse sites, and using multiple species is costly, basing reserve selection primarily on breeding sites of a dominant species may be the best strategy. However, further work is required to establish the extent to which dominant species are typically better indicators of conservation relevance. 相似文献
6.
Clotfelter ED Pedersen AB Cranford JA Ram N Snajdr EA Nolan V Ketterson ED 《Oecologia》2007,154(3):493-503
Resource pulses can have cascading effects on the dynamics of multiple trophic levels. Acorn mast is a pulsed resource in
oak-dominated forests that has significant direct effects on acorn predators and indirect effects on their predators, prey,
and pathogens. We evaluated changes in acorn mast, rodent abundance, raptor abundance, and reproductive success of a ground-nesting
songbird over a 24-year period (1980–2004) in the southern Appalachian Mountains in an effort to determine the relationships
among the four trophic levels. In particular, we examined the following: acorn mast from red oaks (Quercus rubra) and white oaks (Q. alba), abundance of white-footed mice (Peromyscus leucopus) and deer mice (P. maniculatus), population estimates of seven raptor species from three feeding guilds, and nest failure and number of juveniles of dark-eyed
juncos (Junco hyemalis). Finally, we recorded seasonal temperature and precipitation to determine the effects of weather on each trophic level.
We found that weather patterns had delayed effects of up to 3 years on these trophic interactions. Variation in acorn mast,
the keystone resource in this community, was explained by weather conditions as far back as 2 years before the mast event.
Acorn mast, in turn, was a strongly positive predictor of rodent abundance the following year, whereas spring and summer temperature
and raptor abundance negatively affected rodent abundance. Dark-eyed junco nests were more likely to fail in years in which
there were more rodents and raptors. Nest failure rate was a strong predictor of the number of juvenile juncos caught at the
end of the summer. Our results improve our understanding of the complex ecological interactions in oak-dominated forests by
illustrating the importance of abiotic and biotic factors at different trophic levels.
Ethan D. Clotfelter and Amy B. Pedersen contributed equally to the writing of this paper. 相似文献
7.
Ha SH Kim DH Kim IS Kim JH Lee MN Lee HJ Kim JH Jang SK Suh PG Ryu SH 《Cellular signalling》2006,18(12):2283-2291
Mammalian target-of-rapamycin (mTOR), which is a master controller of cell growth, senses a mitogenic signal in part through the lipid second messenger phosphatidic acid (PA), generated by phospholipase D (PLD). To understand further which isozymes of PLD are involved in this process, we compared the effect of PLD isozymes on mTOR activation. We found that PLD2 has an essential role in mitogen-induced mTOR activation as the siRNA-mediated knockdown of PLD2, not of PLD1, profoundly reduced the phosphorylations of S6K1 and 4EBP1, well-known mTOR effectors. Furthermore, exogenous PA-induced mTOR activation was abrogated by PLD2 knockdown, but not by PLD1 knockdown. This abrogation was found to be the result of complex formation between PLD2 and mTOR/raptor. PLD2 possesses a TOS-like motif (Phe-Glu-Val-Gln-Val, a.a. 265–269), through which it interacts with raptor independently of the other TOS motif-containing proteins, S6K1 and 4EBP1. PLD2-dependent mTOR activation appears to require PLD2 binding to mTOR/raptor with lipase activity, since lipase-inactive PLD2 cannot trigger mTOR activation despite its ability to interact with mTOR/raptor. Abrogation of mitogen-dependent mTOR activation by PLD2 knockdown was rescued only by wild type PLD2, but not by raptor binding-deficient and lipase-inactive PLD2. Our results demonstrate the importance of localized PA generation for the mitogen-induced activation of mTOR, which is achieved by a specific interaction between PLD2 and mTOR/raptor. 相似文献
8.
The present study has aimed to verify the influence of calcineurin and mTOR pathways in skeletal muscle longitudinal growth
induced by stretching. Male Wistar rats were treated with cyclosporin-A or rapamycin for 10 days. To promote muscle stretching,
casts were positioned so as completely to dorsiflex the plantar-flexor muscles at the ankle in one hind limb during the last
4 days of treatment with either cyclosporin-A or rapamycin. Thereafter, we determined soleus length, weight, protein content,
and phenotype. In addition, NFATc1, Raptor, S6K1, 4E-BP1, iNOS, and nNOS gene expression in the soleus were determined by
real-time polymerase chain reaction. Soleus length, weight, and protein content were significantly reduced by rapamycin treatment
in animals submitted to stretching (P<0.05). In contrast, cyclosporin-A treatment did not alter these parameters. In all cyclosporin-A treated groups, there was
a significant reduction in NFATc1 expression (P<0.001). Similarly, a significant reduction was noted in Raptor (P<0.001) and S6K1 (P<0.01) expression in all rapamycin-treated groups. No alteration was observed in 4E-BP1 gene expression among rapamycin-treated
groups. Stretching increased gene expression of both NOS isoforms in skeletal muscle. Rapamycin treatment did not interfere
with NOS gene expression (P<0.05). Cyclosporin-A treatment did not impair muscle growth induced by stretching but instead caused a marked slow-to-fast
fiber shift in the soleus; this was attenuated by stretching. The data presented herein indicate that mTOR pathway is involved
in skeletal muscle longitudinal growth.
We gratefully acknowledge the financial support given by FAPESP. 相似文献
9.
Joseph J. Hobbs 《Biodiversity and Conservation》2004,13(12):2209-2226
Due to the value of their nests, there is great pressure on the populations of black-nest swiftlets (Collocalia maximus) and white-nest swiftlets (Collocalia fuciphagus) in the Malaysian provinces of Sarawak and Sabah. The problems are particularly acute at Gunung Mulu National Park, in spite of a complete ban on collection there, and at Niah National Park, where every participant in a complex collection and trading system has an incentive to take more nests than permitted. More successful harvest systems function in Sabah's Gomantong and Madai Caves. Recommendations for improved management of the nest harvest include addressing corruption, ensuring that local people with traditional rights to collect nests do not lose income to illegal immigrant labor and to traders, improving research and education about the swiftlets' behavior and ecology, and moving value-added processing of the nests closer to the caves where they originate and to the people who collect them. 相似文献
10.
Combining limnological and palaeolimnological approaches in assessing degradation of Lake Pskov 总被引:2,自引:2,他引:0
Mihkel Kangur Külli Kangur Reet Laugaste Jaan-Mati Punning Tõnu Möls 《Hydrobiologia》2007,584(1):121-132
Historical spawning grounds for sea lampreys (Petromyzon marinus L.) in most Portuguese river basins are becoming inaccessible due to the construction of impassable dams and/or weirs. Studies
like the one described in this paper are particularly important in areas like the Vouga river basin, where there is a considerable
fishing effort from both professional fishermen and poachers. In fact, for management and conservation purposes, it is important
to clarify several aspects of the sea lamprey spawning run in this particular watershed. Therefore, a total of 30 radio tagged,
migrating sea lampreys were released in the River Vouga and some of its main tributaries during 2004 and 2005. Results from
the tracking sessions were used to determine the effect of poaching on the spawners’ population and the characteristics of
the resting sites used during the upstream movement. The rivers’ stretches were also characterized according to the type of
substrate present in the riverbed and flow type, in order to determine its aptitude to constitute appropriate spawning habitats
for sea lampreys. We have identified in the upstream stretches of River Vouga, and in the tributary River Caima, characteristics
that are particularly suitable for the construction of nests by the spawners. Presence of larvae provided evidence that spawners
migrated into the River Vouga’s upper reaches. However, abundance and age class diversity appeared to be higher downstream
of Sernada and Carvoeiro weirs, corroborating the telemetry data which suggested difficulty in passing these obstacles during
low precipitation years. In the River Caima, migration was most predictable, which might be related to daily water releases
from a small hydropower dam at dusk, that stimulated the lampreys to resume migration. Poaching has had a considerable negative
effect on the success of the tagged lampreys’ migration: 76% of the animals released during 2005 were captured.
Electronic supplementary material Supplementary material is available for this article at and accessible for authorized user 相似文献