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81.
Olfactory sensitivity in tsetse flies: a daily rhythm 总被引:3,自引:0,他引:3
The diurnal tsetse Glossina morsitans morsitans bites especially in early
morning and late afternoon; around midday feeding is at a low. In
laboratory apparatus that measures the amount of locomotion under constant
conditions over the photophase, the flies display a similar patterning of
activity levels. The profile of daily rhythms for G. morsitans reported in
the literature includes a number of motor and sensory motor systems that
fluctuate cophasically. Lacking is a study on the patterning of the senses'
response levels. In this paper we present the first instance of a daily
modulation in the sense of smell. We stimulated the antennae with
concentration series of host-derived odours and measured the spiking rate
of cells at different times during the photophase. The
concentration-response curves suggest that the sensitivity of antennal
olfactory cells flows in parallel with the other daily rhythms. This was
also reflected in electroantennograms (EAGs). The electroantennography was
extended to G. fuscipes fuscipes, whose level of spontaneous locomotor
activity--instead of following a U- shaped pattern--rises gradually over
the photophase. Again, the EAGs appeared to parallel the species' locomotor
activity. What we believe happens is that the organism tones down the
sensitivity of its odour receptors during periods of anticipated inactivity
for reasons of economy.
相似文献
82.
Hunter NB Moseley Andrew N Lane Alex C Belshoff Richard M Higashi Teresa WM Fan 《BMC biology》2012,10(1):1-2
This article is a response to Wang and Luo. See correspondence article http://www.biomedcentral.com/1741-7007/10/30/ [WEBCITE] and the original research article http://www.biomedcentral.com/1741-7007/9/24 [WEBCITE]. 相似文献
83.
An early flowering genetic line of peas (Pisum sativum L.), designated G2, has dominant genes at two different loci, both of which function in short days to greatly extend the reproductive phase and thus to delay apical senescence. Long days (18 hours) promote senescence in this line, but the effect is reversible by reinstatement of short days (9 hours) until 3 to 4 days before the apex senesces. The response to photoperiod was quantitative. Increasing the photoperiod from 14 to 18 hours led to a progressive decrease in the number of nodes formed prior to death of the apex. Induction of senescence was determined by the total number of hours of light and darkness rather than by the length of the dark period. Senescence required flower and fruit development as well as long days. 相似文献
84.
Sabine JM de Brouwer Floris W Kraaimaat Fred CGJ Sweep Marjonne CW Creemers Timothy RDJ Radstake Antoinette IM van Laarhoven Piet LCM van Riel Andrea WM Evers 《Arthritis research & therapy》2010,12(3):R89
Introduction
Stressful events are thought to contribute to the aetiology, maintenance and exacerbation of rheumatic diseases. Given the growing interest in acute stress responses and disease, this review investigates the impact of real-life experimental psychosocial, cognitive, exercise and sensory stressors on autonomic, neuroendocrine and immune function in patients with inflammatory rheumatic diseases. 相似文献85.
86.
Dr. WM. MacLean 《Plant Ecology & Diversity》2013,6(1-4):251-254
87.
Phylogenetic analysis of the outer-membrane-protein genes of Chlamydiae, and its implication for vaccine development 总被引:9,自引:0,他引:9
Examination of 18 complete and 6 partial sequences of the major outer-
membrane protein from 24 chlamydiae isolates was used to reconstruct their
evolutionary relationships. From this analysis, assuming that the clades
with 100% bootstrap support are correct, come the following conclusions:
(1) The tree of these sequences is not congruent with the phylogeny of the
hosts, and thus host switching would seem to have occurred, thereby
limiting the extent to which there has been coevolution of parasite and
host. (2) The tree is also noncongruent with clustering by type of cell
infected, thereby limiting the extent to which there has been coevolution
of parasite and the cell type that it infects. (3) The tree is also
noncongruent with clustering by the organ infected (eyes or genitalia),
thereby limiting the extent to which there has been coevolution of parasite
and the organ that it infects. (4) The tree is also noncongruent with
genital strains arising from lymphogranuloma venereum strains. (5) The tree
is also noncongruent with the geographic site at which the isolates were
obtained, thereby limiting the extent of divergence explained by geographic
separation. (6) There are estimated to be 185 amino acid positions that are
invariable (as opposed to unvaried) in the major outer-membrane protein.
There are 10 unvaried positions in the variable domains, of which 9 appear
to be invariable, giving some reason to hope that development of a vaccine
might be possible. (7) The rate of change of this protein is too small to
see increased divergence over the time span of isolation of these genes,
giving hope to any vaccine having longevity. Bootstrapping supports those
portions of the tree on which the first five conclusions above depend. The
picture that these results provide is more one of pathogen versatility than
one of coevolutionary constraints. In addition, we examined 10 60-KDa,
outer-membrane protein- 2 genes, all but one of which were from these same
strains. The tree was not, among the trachomatis strains, congruent with
the major-outer- membrane protein tree, suggesting that gene exchange could
be occurring among strains. Moreover, there is an apparent slowdown in
divergence in this gene, among the trachomatis strains.
相似文献
88.
Geert Zegels Geert AA Van Raemdonck Wiebren AA Tjalma Xaveer WM Van Ostade 《Proteome science》2010,8(1):63
Cervicovaginal fluid has an important function in the homeostasis and immunity of the lower female genital tract. Analysis
of the cervicovaginal fluid proteome may therefore yield important information about the pathogenesis of numerous gynecological
pathologies. Additionally, cervicovaginal fluid has great potential as a source of biomarkers for these conditions. 相似文献
89.
Andreas WM Dress Christoph Flamm Guido Fritzsch Stefan Grünewald Matthias Kruspe Sonja J Prohaska Peter F Stadler 《Algorithms for molecular biology : AMB》2008,3(1):7
Motivation
Sequence-based methods for phylogenetic reconstruction from (nucleic acid) sequence data are notoriously plagued by two effects: homoplasies and alignment errors. Large evolutionary distances imply a large number of homoplastic sites. As most protein-coding genes show dramatic variations in substitution rates that are not uncorrelated across the sequence, this often leads to a patchwork pattern of (i) phylogenetically informative and (ii) effectively randomized regions. In highly variable regions, furthermore, alignment errors accumulate resulting in sometimes misleading signals in phylogenetic reconstruction. 相似文献90.