共查询到20条相似文献,搜索用时 31 毫秒
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Metazoans establish with microorganisms complex interactions for their mutual benefits. Drosophila, which has already proven useful host model to study several aspects of innate immunity and host-bacteria pathogenic associations has become a powerful model to dissect the mechanisms behind mutualistic host-microbe interactions. Drosophila microbiota is composed of simple and aerotolerant bacterial communities mostly composed of Lactobacillaceae and Acetobactereaceae. Drosophila mono- or poly-associated with lactobacilli strains constitutes a powerful model to dissect the complex interplay between lactobacilli and host biologic traits. Thanks to the genetic tractability of both Drosophila and lactobacilli this association model offers a great opportunity to reveal the underlying molecular mechanisms. Here, we review our current knowledge about how the Drosophila model is helping our understanding of how lactobacilli shapes host biology. 相似文献
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1. The distribution and location of the ciliated protozoan Lagenophrys aselli on the freshwater isopod Asellus aquaticus were studied in relation to water flow over the third pleopod surface. 2. At low densities L. aselli had a significant preference for the anterior centre of the pleopod; however, at the highest densities this preference was no longer significant. The distribution ranged from closer than random at low densities to further than random at the highest densities, and may have been a product of feeding and reproduction of L. aselli as well as the short intermoult period of the host. 3. An individual L. aselli has an effective area of both the lorica and the ciliated feeding disc. The ciliated feeding disc, when extended, may contribute to the presence of a small anterior–posterior gap being left between individuals. 相似文献
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Decady and Thomas (2000, Biometrics 56, 893-896) propose a first-order corrected Umesh-Loughin-Scherer statistic to test for association in an r x c contingency table with multiple column responses. Agresti and Liu (1999, Biometrics 55, 936-943) point out that such statistics are not invariant to the arbitrary designation of a zero or one to a positive response. This paper shows that, in addition, the proposed testing procedure does not hold the correct size when there are strong pairwise associations between responses. 相似文献
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Surveys of ixodoid ticks were performed in Novosibirsk Province (Novosibirsk and Toguchin Districts) and in the vicinity of
Akademgorodok (Novosibirsk) in 2009–2010. The abundance and distribution of ticks were assessed in 8 types of habitats. Ixodes persulcatus (Schulze, 1930) was collected by flagging in Novosibirsk and Toguchin Districts, with the highest densities of 19 ind./km
being observed in habitats with small-leaved trees. Three species of ticks: Ixodes persulcatus, I. pavlovskyi (subspecies I. pavlovskyi occidentalis Filip. et Pan., 1998), and Dermacentor reticulatus (Fabricius, 1794) were recorded in a recreational forest of Akademgorodok. A high abundance (22 ind./km) of I. pavlovskyi was observed in pine forests subjected to considerable recreational load. The abundance of I. persulcatus was the highest in aspen-birch and birch-aspen forests. D. reticulatus was captured in pine forests and fallow lands, its abundance varying from 0.2 to 2 ind./km. 相似文献
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M. Scott Morrison Paul A. Cobine Eric L. Hegg 《Journal of biological inorganic chemistry》2007,12(8):1129-1139
The crystal structure of Cnx1G, an enzyme involved in the biosynthesis of the molybdenum cofactor (Moco) in Arabidopsis thaliana, revealed the remarkable feature of a copper ion bound to the dithiolene unit of a molybdopterin intermediate (Kuper et al. Nature 430:803-806, 2004). To characterize further the role of copper in Moco biosynthesis, we examined the in vivo and/or in vitro activity of two Moco-dependent enzymes, dimethyl sulfoxide reductase (DMSOR) and nitrate reductase (NR), from cells grown under a variety of copper conditions. We found the activities of DMSOR and NR were not affected when copper was depleted from the media of either Escherichia coli or Rhodobacter sphaeroides. These data suggest that while copper may be utilized during Moco biosynthesis when it is available, copper does not appear to be strictly required for Moco biosynthesis in these two organisms. 相似文献
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O. V. Sirotkina A. M. Shaydina T. V. Vavilova E. I. Schwartz 《Russian Journal of Genetics》2005,41(6):683-687
Glycoprotein IIb/IIIa complex, a platelet surface fibrinogen receptor, plays a key role in producing primary hemostasis. At present, only a single mutation in the GPIIIa gene, Leu33Pro, and a single mutation in the GPIIb gene, Ile843Ser, has been described. The mutations are known to enhance signaling functions of the receptor and are associated with the development of arterial thromboses. In the present study, we describe a novel GPIIIa mutation, which is T to G nucleotide substitution in position 1585, resulting in the replacement of Leu for Arg in position 40 of the amino acid sequence of the protein.__________Translated from Genetika, Vol. 41, No. 6, 2005, pp. 838–843.Original Russian Text Copyright © 2005 by Sirotkina, Shaydina, Vavilova, Schwartz. 相似文献
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Federico Buonanno 《Biologia》2011,66(4):648-653
It is known that the microturbellarian Stenostomum sphagnetorum, a common ciliate predator, is very sensitive against different types of toxins produced by other ciliates for chemical defense,
and consequently, it is not able to capture and ingests these ciliates. In particular, when the predator tries to attack one
of these toxin-secreting ciliates, it is forced to regurgitate the captured prey in response to the toxin discharged from
the ciliates. In this study it is shown that after repeated attacks by S. sphagnetorum against two species of toxic ciliates (Spirostomum ambiguum and Spirostomum teres), the predator acquires a behavior of prey selection that leads to the exclusion of these ciliates among the possible prey
and to the distinction between edible and inedible (toxic) ciliates. This learned behavior, which is maintained for days,
is lost only after the asexual reproduction of the microturbellarian. In addition, S. sphagnetorum learns to recognize and avoid specimens of S. ambiguum and S. teres artificially deprived of their toxins, strongly suggesting that the toxins are not exclusively associated in the prey recognition
of the microturbellarian. 相似文献
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In the present study, we discussed the biophysical mechanisms of stationary water exchange with the surroundings by the Nitella translucens and Chara corallina plants. It was postulated that these plants, which subsist under total immersion in a water medium, conduct water exchange
within single cells individually. With the application of the equations of mechanistic formalism for membrane transport to
our investigations (Kargol and Kargol 2000, Kargol 2001, Kargol 2002, Kargol and Kargol 2003, 2003*), it was demonstrated
that individual cells of these plants can simultaneously absorb and remove considerable amounts of water at constant cell
volume, i.e. under stationary conditions. Water absorption is osmosis-driven, and its removal is effected by the cell turgor pressure. 相似文献
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Michael Türkay 《Helgoland Marine Research》2011,65(2):103-109
The thumbnail crab Thia scutellata occurs in the German Bight in at least two stable populations: at Borkum Riff and Loreley Bank. The western (Borkum Riff)
population is larger than the eastern (Loreley Bank) one, probably because of the more frequent ingression of south-western
warmer water along the Dutch coast. The sediments of these two localities are well-sorted middle sands with a very low amount
of finer fractions. 相似文献