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891.
892.
The lagena (the third otolith endorgan in vertebrates) 总被引:1,自引:1,他引:0
V. I. Khorevin 《Neurophysiology》2008,40(2):142-159
In this review, the structure and functions of the lagena (the third otolith organ) in an evolutionary lineage of the vertebrates
are described and discussed. The lagenar macula appears first in the posterior part of the sacculus of elasmobranchs; in these
animals, the lagena is considered to be involved in the balance support (orientation with respect to the gravitation force).
The lagena as a separate endorgan has been described in teleost fishes; in some species, the lagena is connected with the
sacculus, while in other species the interrelations of these structures can be dissimilar. The lagena supplements the functions
of the sacculus; in fishes (animals with no special organ of hearing), it is involved in discrimination of sound oscillations,
identification of the gravitation vector, and orientation in the course of movements within the vertical plane. In amphibians,
the lagena is localized in the posterior part of the sacculus, near the auditory structures; it performs mostly vestibular
and (to a much lesser extent) auditory functions. In amniotes, the lagena was first separated from the sacculus; it is localized
in the cochlear canal, distally with respect to the hearing organ. Information on the functions of the lagena in amniotes
is rather limited and contradictory. Central projections of this organ have been examined practically only in birds. Lagenar
afferents project to the vestibular nuclei and cerebellum, while some fibers come to the auditory nuclei of the medulla. The
lagena in birds can be related to their navigation abilities (birds are supposed to be capable of orienting within the magnetic
field of the Earth due to the magnetic properties of the lagenar otoconia; this structure can also provide detection of movements
along the vertical axis. The close proximity between the otolithic and auditory endorgans in the cochlear canal of amniotes
can be indicative of the functional significance of these interrelations. This aspect, however, remains at present undiscovered.
In mammals (except Monotremata), there is no lagena as an independent endorgan.
Neirofiziologiya/Neurophysiology, Vol. 40, No. 2, pp. 160–178, March–April, 2008. 相似文献
893.
B. K. Shetty 《BMJ (Clinical research ed.)》1994,308(6945):1713-1714
894.
Crislaine Barbosa Daiana K. Garcez Matheus V. Volcan Lizandra J. Robe 《Journal of fish biology》2020,96(1):154-167
Samples of Austrolebias nigrofasciatus (n = 103), an endangered species of annual fish endemic to a small area of the Patos-Mirim lagoon system encompassing the São Gonçalo Channel lowlands, were collected from eight isolated temporary ponds, four located at the known distribution range of the species and four located along the Piratini River lowlands, where morphologically different individuals were found. In the laboratory, fragments of the mitochondrial cytochrome c oxidase I (coI), cytochrome b (cytb) and nuclear rhodopsin (rho) genes were amplified, purified and sequenced for 100, 99 and 58 of these individuals, respectively. Samples were further analysed using phylogenetic and phylogeographic methods to evaluate the patterns of genetic diversity and differentiation presented within and between populations, while assessing their evolutionary history, in order to guide the application of further conservation strategies. We found that the four new populations from the Piratini River lowlands encompass a different lineage of A. nigrofasciatus that diverged from that encountered in the São Gonçalo Channel at approximately 0.165 M years before present, during a population expansion and did not yet attain reciprocal monophyly. This divergence was associated with a glacial event that was preceded by an interglacial period putatively associated with the dispersal. Moreover, significant levels of genetic differentiation and a high number of exclusive haplotypes could be encountered even in micro-geographical scales, as in the comparisons between populations located within the same major lineage, indicating each of them may encompass independent management units. Conservation actions are certainly urgent, especially in the face of signs of a recent bottleneck. 相似文献
895.
896.
897.
N Nakagata K Matsumoto M Anzai A Takahashi Y Takahashi Y Matsuzaki K Miyata 《Jikken dobutsu》1992,41(4):537-540
Spermatozoa of a homozygous transgenic mouse, in which the firefly luciferase gene was expressed under the control of beta-actin promoter, were frozen at -196 degrees C. One fourth of the frozen sperm was later thawed and used for in vitro fertilization. Thirty-six of 65 oocytes (55.4%) developed to the 2-cell stage. All the 2-cell embryos were transferred to the oviducts of pseudopregnant recipients and 23 young (63.9%, 23/36) were born. All of young analyzed carried the transgene and showed the luciferase gene expression. 相似文献
898.
Werner E.C. Muller Jürgen Conrad Rudolf K. Zahn Renate Steffen Gerhard Uhlenbruck Isabel Miller 《Differentiation; research in biological diversity》1984,26(1-3):30-35
Abstract. The Hexactinellida sponge Aphrocallistes vastus contains a soluble aggregation factor (AF) whose purification has been described in this communication. It is characterized by a S°20.w value of 37 and a buoyant density of 1.45 g/cm3 . The AF is a glycoporteinaceous particle composed of three major protein species; no core structure could be visualized. In the presence of Ca2+ , the AF causes secondary aggregation of single cells. The aggregation process is temperature, pH, and ionic strength independent within a broad range. Evidence is presented indicating that two (or more) AF molecules are required for the establishment of a stable cell: cell interaction. In contrast to the AFs from demosponges, the hexactinellid AF functions species-unspecifically. 相似文献
899.
Cimetidine is widely prescribed for the treatment of peptic ulcer disease and has recently been shown to inhibit the metabolism of warfarin, antipyrine and diazepam. To further examine this phenomenon we investigated the effect of various doses of cimetidine and other related drugs on 14C-aminopyrine, 14C-phenacetin and 14C-caffeine breath tests. Cimetidine caused a dose-related inhibition of the metabolism of aminopyrine and caffeine but had no effect on the phenacetin breath test. Metiamide, H1-antihistamines, phenothiazines and local anesthetics also inhibited the aminopyrine breath test. Cyproheptadine had no effect on either phenacetin or caffeine elimination. This study demonstrates a complex drug-drug interaction which may have widespread clinical implications. 相似文献
900.
Andrew Leask 《Journal of cell communication and signaling》2010,4(1):73-74
Connective tissue growth factor (CTGF/CCN2) is overexpressed in diabetes. Diabetic rats possess myocardial and cardiomyocyte hypertrophy. In a recent report, Wang and colleagues (Am J Physiol Cell Physiol. 2009 Jul 22. [Epub ahead of print]) show that CCN2 directly mediates cardiomyocyte hypertrophy as well as that induced by high glucose and fatty acid. CCN2 acted via the TrkA receptor. These data are the subject of this commentary, and emphasize that CCN2 may be an excellent target for therapy in diabetes. 相似文献