排序方式: 共有48条查询结果,搜索用时 250 毫秒
1.
Variation in heat-shock proteins among species of desert fishes (Poeciliidae, Poeciliopsis) 总被引:4,自引:0,他引:4
Analysis of the heat-shock proteins (hsps) of six closely related species
of Poeciliopsis demonstrated the existence of biochemical diversity in the
hsp100, hsp70, hsp60, and hsp30 protein families among species. Each
species expressed five to seven hsp70-related isoforms. Constitutive 70-kD
isoforms were identical among species, but four different patterns of
heat-inducible isoforms were seen in these six species. Members of the
hsp70 family of molecular chaperones are included among the most highly
conserved proteins known, and the possibility of variation in hsp70 among
closely related species has rarely been addressed. The hsp30 family is
known to be less conserved than the hsp70 family, and, as expected, the
Poeciliopsis hsp30 patterns showed more variation. Most of the hsp30
isoforms characteristic of a particular species were unique to that
species. Hsp100 and hsp60 were identical in five of the species, but
alternate isoforms were found in P. monacha. The small size and limited
geographical distribution of the P. monacha population have probably
contributed to the uniqueness of the monacha pattern. Two of the species
were shown to acquire thermotolerance, the ability to withstand normally
lethal temperatures when subjected to a gradual temperature increase.
Rapid-heating protocols commonly used to establish critical thermal maxima
of organisms do not include this inducible component of thermoresistance
and therefore do not adequately assess an organism's capacity to withstand
thermal stress.
相似文献
2.
3.
4.
In clinical neurology, a comprehensive understanding of consciousness has been regarded as an abstract concept - best left
to philosophers. However, times are changing and the need to clinically assess consciousness is increasingly becoming a real-world,
practical challenge. Current methods for evaluating altered levels of consciousness are highly reliant on either behavioural
measures or anatomical imaging. While these methods have some utility, estimates of misdiagnosis are worrisome (as high as
43%) - clearly this is a major clinical problem. The solution must involve objective, physiologically based measures that
do not rely on behaviour. This paper reviews recent advances in physiologically based measures that enable better evaluation
of consciousness states (coma, vegetative state, minimally conscious state, and locked in syndrome). Based on the evidence
to-date, electroencephalographic and neuroimaging based assessments of consciousness provide valuable information for evaluation
of residual function, formation of differential diagnoses, and estimation of prognosis. 相似文献
5.
The ability of captive Grey Parrots Psittacus erithacus to imitate heterospecific sounds is well known. Analysis of a sound recording from Zaire reveals the first evidence of vocal mimicry in the wild of nine species of birds and a bat. Examination of recordings from Gabon and the Ivory Coast indicates that vocal mimicry may be widespread in wild populations. Possible reasons why this phenomenon has not been detected before are discussed. 相似文献
6.
ARTHUR R. I. CRUICKSHANK 《Zoological Journal of the Linnean Society》1994,112(1):151-178
A partial skull and skeleton of a small, juvenile plesiosaur, part of the historically important Philpot Collection from Lyme Regis, England, is described. It is assigned tentatively to EwycMdus arcuatus (Owen, 1840) and has a mosaic of features which make it difficult to place in a superfamily. The characters of the posterior elements of the skull and post-dentary bones are close to those expected in a plesiosauroid, whereas the anterior dentition and symphysis of the lower jaw are more typical of a pliosauroid. The specimen is placed in the Pliosauroidea pending a phylogenetic revision of the Lower Jurassic Plesiosauria. From a reconstruction of the dentition and jaw-closing muscles, it is thought to have been a predator on soft-bodied or lighdy armoured prey, such as belemnoids, ammonites or small fish. 相似文献
7.
8.
9.
10.