scholarly journals Genetic differentiation in pesticide resistance between urban and rural populations of a nontarget freshwater keystone interactor, Daphnia magna

2021 ◽  
Author(s):  
Kristien I. Brans ◽  
Rafaela A. Almeida ◽  
Maxime Fajgenblat
Keyword(s):  
Genetic Differentiation ◽  
Daphnia Magna ◽  
Rural Populations ◽  
Pesticide Resistance

scholarly journals Urbanization drives genetic differentiation in physiology and structures the evolution of pace-of-life syndromes in the water flea Daphnia magna

2018 ◽  
Vol 285 (1883) ◽  
pp. 20180169 ◽  
Author(s):  
Kristien I. Brans ◽  
Robby Stoks ◽  
Luc De Meester
Keyword(s):  
Life History ◽  
Energy Metabolism ◽  
Genetic Differentiation ◽  
Daphnia Magna ◽  
Urban Life ◽  
Stress Physiology ◽  
Physiological Traits ◽  
Rural Populations ◽  
Pace Of Life ◽  
Baseline Activity

Natural and human-induced stressors elicit changes in energy metabolism and stress physiology in populations of a wide array of species. Cities are stressful environments that may lead to differential selection on stress-coping mechanisms. Given that city ponds are exposed to the urban heat island effect and receive polluted run-off, organisms inhabiting these ecosystems might show genetic differentiation for physiological traits enabling them to better cope with higher overall stress levels. A common garden study with 62 Daphnia magna genotypes from replicated urban and rural populations revealed that urban Daphnia have significantly higher concentrations of total body fat, proteins and sugars. Baseline activity levels of the antioxidant defence enzymes superoxide dismutase (SOD) and glutathione-S-transferase (GST) were higher in rural compared with city populations, yet urban animals were equally well protected against lipid peroxidation. Our results add to the recent evidence of urbanization-driven changes in stress physiology and energy metabolism in terrestrial organisms. Combining our results with data on urban life history evolution in Daphnia revealed that urban genotypes show a structured pace-of-life syndrome involving both life-history and physiological traits, whereas this is absent in rural populations.

Membrane-bound vesicles associated with the microvilli in the midgut of the freshwater microcrustacean, Daphnia magna

1983 ◽  
Vol 41 ◽  
pp. 480-481
Author(s):  
Patricia L. Jansma
Keyword(s):  
Daphnia Magna ◽  
Intestinal Epithelial Cells ◽  
Uranyl Acetate ◽  
Intestinal Epithelial ◽  
Chlamydomonas Reinhardii ◽  
Thin Sections ◽  
Saturated Water ◽  
Cacodylate Buffer ◽  
Membrane Bound ◽  
Ethanol Series

The presence of the membrane bound vesicles or blebs on the intestinal epithelial cells has been demonstrated in a variety of vertebrates such as chicks, piglets, hamsters, and humans. The only invertebrates shown to have these microvillar blebs are two species of f1ies. While investigating the digestive processes of the freshwater microcrustacean, Daphnia magna, the presence of these microvillar blebs was noticed.Daphnia magna fed in a suspension of axenically grown green alga, Chlamydomonas reinhardii for one hour were narcotized with CO2 saturated water. The intestinal tracts were excised in 2% glutaraldehyde in 0.2 M cacodyl ate buffer and then placed in fresh 2% glutaraldehyde for one hour. After rinsing in 0.1 M cacodylate buffer, the sample was postfixed in 2% OsO4, dehydrated with a graded ethanol series, infiltrated and embedded with Epon-Araldite. Thin sections were stained with uranyl acetate and Reynolds lead citrate before viewing with the Philips EM 200.

Computer Reconstruction of the Cellular Architecture of the Daphnia Magna Optic Ganglion

1975 ◽  
Vol 33 ◽  
pp. 284-285
Author(s):  
E. R. Macagno ◽  
C. Levinthal
Keyword(s):  
Daphnia Magna ◽  
Genetic Background ◽  
Compound Eye ◽  
Synaptic Connectivity ◽  
Serial Sections ◽  
Cross Sectional ◽  
Small Crustacean ◽  
Optic Ganglion ◽  
Structural Invariance ◽  
High Degree

The optic ganglion of Daphnia Magna, a small crustacean that reproduces parthenogenetically contains about three hundred neurons: 110 neurons in the Lamina or anterior region and about 190 neurons in the Medulla or posterior region. The ganglion lies in the midplane of the organism and shows a high degree of left-right symmetry in its structures. The Lamina neurons form the first projection of the visual output from 176 retinula cells in the compound eye. In order to answer questions about structural invariance under constant genetic background, we have begun to reconstruct in detail the morphology and synaptic connectivity of various neurons in this ganglion from electron micrographs of serial sections (1). The ganglion is sectioned in a dorso-ventra1 direction so as to minimize the cross-sectional area photographed in each section. This area is about 60 μm x 120 μm, and hence most of the ganglion fit in a single 70 mm micrograph at the lowest magnification (685x) available on our Zeiss EM9-S.

Treatment of Pediatric Overweight in Rural Populations

2007 ◽  
Author(s):  
Ann McGrath Davis
Keyword(s):  
Rural Populations ◽  
Pediatric Overweight

Mise en évidence des effets sublétaux sur des populations de daphnies (Daphnia magna)

1981 ◽  
Vol 12 (1) ◽  
pp. 63-79
Author(s):  
R. Cabridenc ◽  
Bui Thi ◽  
H. Lepailleur
Keyword(s):  
Daphnia Magna

2020–2021 Florida Citrus Production Guide: Pesticide Resistance and Resistance Management

EDIS ◽  
2020 ◽  
Author(s):  
Lauren Marie Diepenbrock ◽  
Megan M. Dewdney ◽  
Ramdas Kanissery
Keyword(s):  
Resistance Management ◽  
Pesticide Resistance ◽  
Citrus Production ◽  
Florida Citrus

An Overview of Rural to Urban Migration in China and Social Challenges

2019 ◽  
Vol 16 (2) ◽  
pp. 273-282
Author(s):  
Ziwei Qi
Keyword(s):  
Agricultural Production ◽  
Rural Populations ◽  
Urban Migration ◽  
Open Market ◽  
Labour Demand ◽  
Social Challenges ◽  
The Past ◽  
Internal Migrations ◽  
Rural To Urban Migration ◽  
Employment Sectors

The rural to urban migration in China represents one of the greatest internal migrations of people in history as rural populations have moved to cities in response to growing labour demand. One major cause of the increased labour demand was the “Reform and Open Market Policy” initiated at the end of the 1970s. The policy amplified the rural to urban divide by promoting a more thoroughly market-based economy with a corresponding reduction in the importance of agricultural production and a greater emphasis on non-agricultural market sectors. As a result, a series of economic reforms have drastically changed the cultural and social aspects of the rural area over the past three decades. Many social problems have been created due to rural to urban migration. These problems include institutional discrimination because of the restrictive household registration policies; social stigmatisation and discrimination in state-owned employment sectors and among urban residents; psychological distress and feelings of alienation.

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