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Organisms Diversity & Evolution - Chaetopteridae — the parchment worms — comprise a group of early branching annelids with a scarcely investigated neuroanatomy and neurogenesis. Due... 相似文献
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Andrea Swei Kerry E. OConnor Lisa I. Couper Jose Thekkiniath Patricia A. Conrad Kerry A. Padgett Joseph Burns Melissa H. Yoshimizu Ben Gonzales Brandon Munk Nicholas Shirkey Lora Konde Choukri Ben Mamoun Robert S. Lane Anne Kjemtrup 《International journal for parasitology》2019,49(2):95-103
Babesiosis is a potentially fatal tick-borne zoonotic disease caused by a species complex of blood parasites that can infect a variety of vertebrates, particularly dogs, cattle, and humans. In the United States, human babesiosis is caused by two distinct parasites, Babesia microti and Babesia duncani. The enzootic cycle of B. microti, endemic in the northeastern and upper midwestern regions, has been well characterised. In the western United States, however, the natural reservoir host and tick vector have not been identified for B. duncani, greatly impeding efforts to understand and manage this zoonotic disease. Two and a half decades after B. duncani was first described in a human patient in Washington State, USA, we provide evidence that the enzootic tick vector is the winter tick, Dermacentor albipictus, and the reservoir host is likely the mule deer, Odocoileus hemionus. The broad, overlapping ranges of these two species covers a large portion of far-western North America, and is consistent with confirmed cases of B. duncani in the far-western United States. 相似文献
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Journal of Mathematical Biology - The stationary distribution of a sample taken from a Wright–Fisher diffusion with general small mutation rates is found using a coalescent approach. The... 相似文献
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Nicole C. Thunes Rachel A. Conrad Haitham H. Mohammed Yongtao Zhu Paul Barbier Jason P. Evenhuis David Perez-Pascual Jean-Marc Ghigo Ryan S. Lipscomb John R. Schneider Nan Li Devon H. Erbes Clayton Birkett Benjamin R. LaFrentz Timothy J. Welch Mark J. McBride 《Applied and environmental microbiology》2022,88(3)
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Methane production in littoral sediment of Lake Constance 总被引:7,自引:0,他引:7
Maximum rates of CH4 production in the littoral sediment were observed in 2–5 cm depth. The CH4 production rates increased during the year from about 5 mmol m−2d−1 in December to a maximum of about 95 mmol m−2d−1 in September. CH4 production rates showed a temperature optimum at 30°C and an apparent activation energy of 76 kJ mol−1. A large part of the seasonality of CH4 production could be ascribed to the change of the sediment temperature. Most of the produced CH4 was lost by ebullition. Gas bubbles contained about 60–70% CH4 with an average δ13C of −56.2% and δD of −354%, and 2% CO2 with an average δ13C of −14.1% indicating that CH4 was produced from methyl carbon, i.e. mainly using acetate as methanogenic substrate. This result was confirmed by inhibition of methanogenesis with chloroform which resulted in an accumulation rate of acetate equivalent to 81% of the rate of CH4 production. Most probable numbers of methanogenic bacteria were in the order of 104 bacteria g−1d.w. sediment for acetate-, methanol- or formate-utilizing, and of 105 for H2-utilizing methanogens. The turnover times of acetate were in the order of 2.3–4.8 h which, with in situ acetate concentrations of about 25–50 μM, resulted in rates of acetate turnover which were comparable to the rates of CH4 production. The respiratory index (RI) showed that [2−14C]acetate was mainly used by methanogenesis rather than by respiratory processes, although the zone of CH4 production in the sediment overlapped with the zone of sulfate reduction. 相似文献
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N-Methyl-D-aspartate (NMDA)-type glutamate receptors play important roles at developing synapses and in activity-dependent synaptic plasticity. Recent studies in Aplysia suggest that NMDA-like receptors may contribute to some forms of plasticity of sensorimotor synapses accompanying associative learning. We examined at various times after plating neurons in culture the contribution of NMDA- and alpha-amino-3 hydroxy-5 methyl-4 isoxazole proprionic acid (AMPA)-like glutamate receptors to responses evoked in motor cell L7 either by action potentials in sensory neurons (SNs) or by focal applications of glutamate. We found that (D,L)-2-amino-5-phosphopentoic acid-sensitive receptors contributed significantly to postsynaptic responses in 1-day cultures but contributed little in the same cultures on day 4. By contrast, postsynaptic responses on day 4 increased significantly in amplitude by the addition of functional 6-cyano-7 nitroquinoxaline-2,3-dione- or 1-(4-aminophenyl)-4-methyl-7,8-methylendioxy-5H-2,3-benzodiazepine hydrochloride-sensitive receptors. Receptors with NMDA-like properties are detected on day 1 only at sites on L7 apposed to SN varicosities, and are not detected on L7 cultured alone. The results indicate that changes in expression and distribution of functional receptors on L7 accompany the formation and maturation of SN synapses. Signals from the SN appear to trigger expression and clustering of functional NMDA-like receptors at sites contacted by presynaptic structures capable of transmitter release. With time, functional AMPA-like receptors are added to these sites enhancing synaptic efficacy. The results are consistent with the idea that the expression and sequential clustering of NMDA- and AMPA-type receptors may be essential for the formation and maturation of central synapses. 相似文献