scholarly journals An overview of the evolution of overproduced esterases in the mosquito Culex pipiens

1998 ◽  
Vol 353 (1376) ◽  
pp. 1707-1711 ◽  
Author(s):  
M. Raymond ◽  
C. Chevillon ◽  
T. Guillemaud ◽  
T. Lenormand ◽  
N. Pasteur

Insecticide resistance genes have developed in a wide variety of insects in response to heavy chemical application. Few of these examples of adaptation in response to rapid environmental change have been studied both at the population level and at the gene level. One of these is the evolution of the overproduced esterases that are involved in resistance to organophosphate insecticides in the mosquito Culex pipiens . At the gene level, two genetic mechanisms are involved in esterase overproduction, namely gene amplification and gene regulation. At the population level, the co–occurrence of the same amplified allele in distinct geographic areas is best explained by the importance of passive transportation at the worldwide scale. The long–term monitoring of a population of mosquitoes in southern France has enabled a detailed study to be made of the evolution of resistance genes on a local scale, and has shown that a resistance gene with a lower cost has replaced a former resistance allele with a higher cost.

2019 ◽  
Author(s):  
Ted Ozersky ◽  
Teofil Nakov ◽  
Stephanie E. Hampton ◽  
Nicholas L. Rodenhouse ◽  
Kirill Shchapov ◽  
...  

AbstractClimate warming impacts ecosystems through multiple interacting pathways, including via direct thermal responses of individual taxa and the combined responses of closely interacting species. In this study we examined how warming and infection by an oomycete parasite affect the dominant zooplankter of Russia’s Lake Baikal, the endemic cold-adapted stenotherm Epischura baikalensis (Copepoda). We used a combination of laboratory experiments, long-term monitoring data and population modeling. Experiments showed large thermal mismatch between host and parasite, with strong negative effects of warm temperatures on E. baikalensis survival and reproduction and a negative synergistic effect of Saprolegnia infection. However, Saprolegnia infection had an unexpected positive effect on E. baikalensis reproductive output, which may be consistent with fecundity compensation by infected females. Long-term monitoring data showed that Saprolegnia infections were most common during the warmest periods of the year and that infected individuals tended to accumulate in deep water. Population models, parameterized with experimental and literature data, correctly predicted the timing of Saprolegnia epizootics, but overestimated the negative effect of warming on E.baikalensis populations. Models suggest that diel vertical migration may allow E. baikalensis to escape the negative effects of increasing temperatures and parasitism and enable E. baikalensis to persist as Lake Baikal warms. Our results contribute to understanding of how multiple interacting stressors affect warming pelagic ecosystems of cold lakes and oceans and show that the population-level consequences of thermal mismatch between hosts and parasites can vary seasonally, interannual and spatially.


2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Xiaoyun Yuan ◽  
Mengqi Ji ◽  
Jiamin Wu ◽  
David J. Brady ◽  
Qionghai Dai ◽  
...  

AbstractArray cameras removed the optical limitations of a single camera and paved the way for high-performance imaging via the combination of micro-cameras and computation to fuse multiple aperture images. However, existing solutions use dense arrays of cameras that require laborious calibration and lack flexibility and practicality. Inspired by the cognition function principle of the human brain, we develop an unstructured array camera system that adopts a hierarchical modular design with multiscale hybrid cameras composing different modules. Intelligent computations are designed to collaboratively operate along both intra- and intermodule pathways. This system can adaptively allocate imagery resources to dramatically reduce the hardware cost and possesses unprecedented flexibility, robustness, and versatility. Large scenes of real-world data were acquired to perform human-centric studies for the assessment of human behaviours at the individual level and crowd behaviours at the population level requiring high-resolution long-term monitoring of dynamic wide-area scenes.


2020 ◽  
Author(s):  
Zheng Li ◽  
Yunru Chen ◽  
Geyin Zhang ◽  
Qingmei Li ◽  
Junying Sun ◽  
...  

Abstract Background: Sulfonamides is the second most popular antibiotic in many countries, which leads to the widespread emergence of sulfonamides resistance. Sul3 is a late sulfanilamide resistance gene, whose research is relatively little. Result: 46 sul3 positive E. coli strains were separated. A total of 12 ST types were observed, and 1 of those was previously unknown type. The ST350 is the most numerous type. All isolates were multidrug-resistant E. coli, with high antimicrobial rates to penicillin, ceftriaxone sodium, streptomycin, tetracycline, ciprofloxacin, gatifloxacin and chloramphenicol (100%, 73.9%, 82.6%, 100%, 80.4%, 71.7% and 97.8%), and with at least 3 resistance genes in addition to sul3. The plasmids transfered from 3 sul3-positive isolates to C600, the most of which brought 7 antibiotic resistance and increased resistance genes to C600. The transferred sul3 gene and the plasmid that carries it could be stably inherited in the recipient bacteria for at least 20 days. Those plasmids had no effect on the growth of the recipient bacteria, but it would greatly reduce (at least 60 time) the in vitro competitiveness of the strains. Conclusions: In Nanning, these sul3-positive Escherichia coli have strong antimicrobial resistance, and the plasmid carrying sul3 has the ability to transfer multiple resistance genes, so long-term monitoring is necessary. Since the transferred plasmid will greatly reduce the in vitro competitiveness of the strain, we can consider limiting the spread of antimicrobial in this respect.


Author(s):  
Barbara S. Minsker ◽  
Charles Davis ◽  
David Dougherty ◽  
Gus Williams

Author(s):  
Robert Klinck ◽  
Ben Bradshaw ◽  
Ruby Sandy ◽  
Silas Nabinacaboo ◽  
Mannie Mameanskum ◽  
...  

The Naskapi Nation of Kawawachikamach is an Aboriginal community located in northern Quebec near the Labrador Border. Given the region’s rich iron deposits, the Naskapi Nation has considerable experience with major mineral development, first in the 1950s to the 1980s, and again in the past decade as companies implement plans for further extraction. This has raised concerns regarding a range of environmental and socio-economic impacts that may be caused by renewed development. These concerns have led to an interest among the Naskapi to develop a means to track community well-being over time using indicators of their own design. Exemplifying community-engaged research, this paper describes the beginning development of such a tool in fall 2012—the creation of a baseline of community well-being against which mining-induced change can be identified. Its development owes much to the remarkable and sustained contribution of many key members of the Naskapi Nation. If on-going surveying is completed based on the chosen indicators, the Nation will be better positioned to recognize shifts in its well-being and to communicate these shifts to its partners. In addition, long-term monitoring will allow the Naskapi Nation to contribute to more universal understanding of the impacts of mining for Indigenous peoples.


Sign in / Sign up

Export Citation Format

Share Document