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51.
52.
Gerald Carter Diana Schoeppler Marie Manthey Mirjam Kn?rnschild Annette Denzinger 《PloS one》2015,10(9)
Many birds and mammals produce distress calls when captured. Bats often approach speakers playing conspecific distress calls, which has led to the hypothesis that bat distress calls promote cooperative mobbing. An alternative explanation is that approaching bats are selfishly assessing predation risk. Previous playback studies on bat distress calls involved species with highly maneuverable flight, capable of making close passes and tight circles around speakers, which can look like mobbing. We broadcast distress calls recorded from the velvety free-tailed bat, Molossus molossus, a fast-flying aerial-hawker with relatively poor maneuverability. Based on their flight behavior, we predicted that, in response to distress call playbacks, M. molossus would make individual passing inspection flights but would not approach in groups or approach within a meter of the distress call source. By recording responses via ultrasonic recording and infrared video, we found that M. molossus, and to a lesser extent Saccopteryx bilineata, made more flight passes during distress call playbacks compared to noise. However, only the more maneuverable S. bilineata made close approaches to the speaker, and we found no evidence of mobbing in groups. Instead, our findings are consistent with the hypothesis that single bats approached distress calls simply to investigate the situation. These results suggest that approaches by bats to distress calls should not suffice as clear evidence for mobbing. 相似文献
53.
Manon R. Haverkate Mirjam J. D. Dautzenberg Tjaco J. M. Ossewaarde Anneke van der Zee Jan G. den Hollander Annet Troelstra Marc J. M. Bonten Martin C. J. Bootsma 《PloS one》2015,10(10)
During a large hospital outbreak of OXA-48 producing bacteria, most K. pneumoniae
OXA-48 isolates were phenotypically resistant to meropenem or imipenem, whereas most E. coli
OXA-48 isolates were phenotypically susceptible to these antibiotics. In the absence of molecular gene-detection E. coli
OXA-48 could remain undetected, facilitating cross-transmission and horizontal gene transfer of bla
OXA-48. Based on 868 longitudinal molecular microbiological screening results from patients carrying K. pneumoniae
OXA-48 (n = 24), E. coli
OXA-48 (n = 17), or both (n = 40) and mathematical modelling we determined mean durations of colonisation (278 and 225 days for K. pneumoniae
OXA-48 and E. coli
OXA-48, respectively), and horizontal gene transfer rates (0.0091/day from K. pneumoniae to E. coli and 0.0015/day vice versa). Based on these findings the maximum effect of horizontal gene transfer of bla
OXA-48 originating from E. coli
OXA-48 on the basic reproduction number (R
0) is 1.9%, and it is, therefore, unlikely that phenotypically susceptible E. coli
OXA-48 will contribute significantly to the spread of bla
OXA-48. 相似文献
54.
Mirjam M. J. Jacobs Ben Vosman Vivianne G. A. A. Vleeshouwers Richard G. F. Visser Betty Henken Ronald G. van den Berg 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2010,120(4):785-796
Mapping resistance genes is usually accomplished by phenotyping a segregating population for the resistance trait and genotyping
it using a large number of markers. Most resistance genes are of the NBS-LRR type, of which an increasing number is sequenced.
These genes and their analogs (RGAs) are often organized in clusters. Clusters tend to be rather homogenous, viz. containing
genes that show high sequence similarity with each other. From many of these clusters the map position is known. In this study
we present and test a novel method to quickly identify to which cluster a new resistance gene belongs and to produce markers
that can be used for introgression breeding. We used NBS profiling to identify markers in bulked DNA samples prepared from
resistant and susceptible genotypes of small segregating populations. Markers co-segregating with resistance can be tested
on individual plants and directly used for breeding. To identify the resistance gene cluster a gene belongs to, the fragments
were sequenced and the sequences analyzed using bioinformatics tools. Putative map positions arising from this analysis were
validated using markers mapped in the segregating population. The versatility of the approach is demonstrated with a number
of populations derived from wild Solanum species segregating for P. infestans resistance. Newly identified P. infestans resistance genes originating from S. verrucosum, S. schenckii, and S. capsicibaccatum could be mapped to potato chromosomes 6, 4, and 11, respectively. 相似文献
55.
Diversity, activity, and abundance of sulfate-reducing bacteria in saline and hypersaline soda lakes
Foti M Sorokin DY Lomans B Mussman M Zacharova EE Pimenov NV Kuenen JG Muyzer G 《Applied and environmental microbiology》2007,73(7):2093-2100
Soda lakes are naturally occurring highly alkaline and saline environments. Although the sulfur cycle is one of the most active element cycles in these lakes, little is known about the sulfate-reducing bacteria (SRB). In this study we investigated the diversity, activity, and abundance of SRB in sediment samples and enrichment cultures from a range of (hyper)saline soda lakes of the Kulunda Steppe in southeastern Siberia in Russia. For this purpose, a polyphasic approach was used, including denaturing gradient gel electrophoresis of dsr gene fragments, sulfate reduction rate measurements, serial dilutions, and quantitative real-time PCR (qPCR). Comparative sequence analysis revealed the presence of several novel clusters of SRB, mostly affiliated with members of the order Desulfovibrionales and family Desulfobacteraceae. We detected sulfate reducers and observed substantial sulfate reducing rates (between 12 and 423 micromol/dm(3) day(-1)) for most lakes, even at a salinity of 475 g/liter. Enrichments were obtained at salt saturating conditions (4 M Na(+)), using H(2) or volatile fatty acids as electron donors, and an extremely halophilic SRB, strain ASO3-1, was isolated. Furthermore, a high dsr gene copy number of 10(8) cells per ml was detected in a hypersaline lake by qPCR. Our results indicate the presence of diverse and active SRB communities in these extreme ecosystems. 相似文献
56.
Kaestli M Mayo M Harrington G Watt F Hill J Gal D Currie BJ 《Applied and environmental microbiology》2007,73(21):6891-6897
Burkholderia pseudomallei, the cause of the severe disease melioidosis in humans and animals, is a gram-negative saprophyte living in soil and water of areas of endemicity such as tropical northern Australia and Southeast Asia. Infection occurs mainly by contact with wet contaminated soil. The environmental distribution of B. pseudomallei in northern Australia is still unclear. We developed and evaluated a direct soil B. pseudomallei DNA detection method based on the recently published real-time PCR targeting the B. pseudomallei type III secretion system. The method was evaluated by inoculating different soil types with B. pseudomallei dilution series and by comparing B. pseudomallei detection rate with culture-based detection rate for 104 randomly collected soil samples from the Darwin rural area in northern Australia. We found that direct soil B. pseudomallei DNA detection not only was substantially faster than culture but also proved to be more sensitive with no evident false-positive results. This assay provides a new tool to detect B. pseudomallei in soil samples in a fast and highly sensitive and specific manner and is applicable for large-scale B. pseudomallei environmental screening studies or in outbreak situations. Furthermore, analysis of the 104 collected soil samples revealed a significant association between B. pseudomallei-positive sites and the presence of animals at these locations and also with moist, reddish brown-to-reddish gray soils. 相似文献
57.
van Dieën JH Spanjaard M Konemann R Bron L Pijnappels M 《Journal of biomechanics》2007,40(16):3641-3649
Stepping down an elevation in ongoing gait is a common task that can cause falls when the level change is unexpected. The aim of this study was to compare expected and unexpected stepping down. We hypothesized that unexpected stepping would lead to loss of control over the movement and potentially falls due to buckling of the leading leg at landing. Ten male subjects repeatedly walked over a platform on which they stepped down an expected 10-cm height difference. In 5 out of 50 trials, the height difference was encountered unexpectedly early. Kinematics and ground reaction forces under both feet were measured during the stride in which the height difference was negotiated. Stepping down involved a substantial increase in forward horizontal and angular momenta (approximately 40 N s and 20 N ms). In expected stepping down, step length was significantly increased (17%), which allowed control of these forward horizontal and angular momenta immediately following landing. In unexpected stepping down, the time between expected ground contact and actual ground contact (110 ms) appeared too short to substantially adjust leg movement and increase step length. Although buckling of the leg did not occur, presumably due to its more vertical orientation at landing, momentum could not be sufficiently attenuated at landing, but a fall was prevented by a rapid step of the trailing limb. The lack of control of momentum might cause a fall, when the capacity to make such a rapid step falls short, as in the elderly, or when the height difference is larger. 相似文献
58.
59.
Mirjam?S. de?Pagter Markus?J. van?Roosmalen Annette?F. Baas Ivo Renkens Karen?J. Duran Ellen van?Binsbergen Masoumeh Tavakoli-Yaraki Ron Hochstenbach Lars?T. van?der?Veken Edwin Cuppen Wigard?P. Kloosterman 《American journal of human genetics》2015,96(4):651-656
Chromothripsis represents an extreme class of complex chromosome rearrangements (CCRs) with major effects on chromosomal architecture. Although recent studies have associated chromothripsis with congenital abnormalities, the incidence and pathogenic effects of this phenomenon require further investigation. Here, we analyzed the genomes of three families in which chromothripsis rearrangements were transmitted from a mother to her child. The chromothripsis in the mothers resulted in completely balanced rearrangements involving 8–23 breakpoint junctions across three to five chromosomes. Two mothers did not show any phenotypic abnormalities, although 3–13 protein-coding genes were affected by breakpoints. Unbalanced but stable transmission of a subset of the derivative chromosomes caused apparently de novo complex copy-number changes in two children. This resulted in gene-dosage changes, which are probably responsible for the severe congenital phenotypes of these two children. In contrast, the third child, who has a severe congenital disease, harbored all three chromothripsis chromosomes from his healthy mother, but one of the chromosomes acquired de novo rearrangements leading to copy-number changes. These results show that the human genome can tolerate extreme reshuffling of chromosomal architecture, including breakage of multiple protein-coding genes, without noticeable phenotypic effects. The presence of chromothripsis in healthy individuals affects reproduction and is expected to substantially increase the risk of miscarriages, abortions, and severe congenital disease. 相似文献
60.
Anna Stincone Alessandro Prigione Thorsten Cramer Mirjam M. C. Wamelink Kate Campbell Eric Cheung Viridiana Olin‐Sandoval Nana‐Maria Grüning Antje Krüger Mohammad Tauqeer Alam Markus A. Keller Michael Breitenbach Kevin M. Brindle Joshua D. Rabinowitz Markus Ralser 《Biological reviews of the Cambridge Philosophical Society》2015,90(3):927-963