scholarly journals Author Correction: Environmental DNA size sorting and degradation experiment indicates the state of Daphnia magna mitochondrial and nuclear eDNA is subcellular

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rashnat Moushomi ◽  
Gregory Wilgar ◽  
Gary Carvalho ◽  
Simon Creer ◽  
Mathew Seymour
2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Rashnat Moushomi ◽  
Gregory Wilgar ◽  
Gary Carvalho ◽  
Simon Creer ◽  
Mathew Seymour

2021 ◽  
Vol 4 ◽  
Author(s):  
Tiina Laamanen ◽  
Veera Norros ◽  
Sanna Suikkanen ◽  
Mikko Tolkkinen ◽  
Kristiina Vuorio ◽  
...  

Environmental DNA (eDNA) and other molecular based approaches are revolutionizing the field of biomonitoring. These approaches undergo rapid modifications, and it is crucial to develop the best practices by sharing the newest information and knowledge. In our ongoing project we: assess the state-of-the-art of eDNA methods at Finnish Environment Institute SYKE; identify concrete next steps towards the long-term aim of implementing eDNA methods into environmental and biomonitoring; promote information exchange on eDNA methods and advance future research efforts both within SYKE and with our national and international partners. assess the state-of-the-art of eDNA methods at Finnish Environment Institute SYKE; identify concrete next steps towards the long-term aim of implementing eDNA methods into environmental and biomonitoring; promote information exchange on eDNA methods and advance future research efforts both within SYKE and with our national and international partners. Scientific background Well-functioning and intact natural ecosystems are essential for human well-being, provide a variety of ecosystem services and contain a high diversity of organisms. However, human activities such as eutrophication, pollution, land-use or invasive species, are threatening the state and functioning of ecosystems from local to global scale (e.g. Benateau et al. 2019; Reid et al. 2018; Vörösmarty et al. 2010). New molecular techniques in the field and in the laboratory have enabled sampling and identification of much of terrestrial, marine and freshwater biodiversity. These include environmental DNA (eDNA, e.g. Valentini et al. 2016) and bulk-sample DNA metabarcoding approaches (e.g. Elbrecht et al. 2017) and targeted RNA-based methods (e.g. Mäki and Tiirola 2018). The eDNA technique uses DNA that is released from organisms into their environment, from which a signal of organisms’ presence in the system can be obtained. For example, in aquatic ecosystems, eDNA is typically extracted from sediment or filtered water samples (e.g. Deiner et al. 2016), and this approach is distinguished from bulk DNA metabarcoding, where organisms are directly identified from e.g. complete biological monitoring samples (e.g. Elbrecht et al. 2017). Despite the demonstrated potential of environmental and bulk-sample DNA metabarcoding approaches in recent years, there are still significant bottlenecks to their routine use that need to be addressed (e.g. Pawlowski et al. 2020). Methods and implementati on The project is divided into three work packages: WP1 Gathering existing knowledge, identifying knowledge gaps and proposing best practices, WP2 Roadmap to implementation and WP3 eDNA monitoring pilot. Please see more details in the Fig. 1


2021 ◽  
Vol 100 (1) ◽  
pp. 30-35
Author(s):  
Larisa M. Sosedova ◽  
Evgeniy A. Titov ◽  
Mikhail A. Novikov ◽  
Irina A. Shurygina ◽  
Mikhail G. Shurygin

This review contains analysis and generalization of data about aquatic ecotoxicity of metal nanoparticles study. This study showed the effect of their impact on the viability of protozoa, algae, microbial communities. A multi-level approach proves to be important as it considers the main characteristics of the studied materials: solubility, agglomeration, degradation. The transformation in the aquatic environment is important in the study of aquatic ecotoxicity. For assessing the state of environment in ecotoxicological experiments, the Great Daphnia (Daphnia magna) was used as a critical organism of the freshwater ecosystem, due to its high sensitivity to environmental pollution, small body size, and short lifespan. In this regard, numerous studies on the effect of nanoparticles on the state of aquatic ecosystem are carried out on Daphnia magna. The review presents some methodological approaches to test the toxicity of nanoparticles in aquatic environment and assessing their stability. It is proposed to carry out a total assessment of the effect based on the content of pollutants in water with different toxic potentials, given that organisms, including aquatic organisms, are rarely exposed to certain chemicals. A promising approach to the assessment of cytotoxicity is high-throughput screening (HTS), which offers the opportunity to quickly test the effects of nanoparticles on bacteria in parallel in several concentrations. Algae are the most important participants in ecosystem and main components of the food chain. It allows recommending them as a marker when monitoring the environmental pollution by metal nanoparticles. Particular attention is paid to perspectives for further wider use of nanostructured products as adsorbents in wastewater treatment and recultivation processes. Search and selection of sources for review carried out in open databases, including PubMed, Scopus, Google Scholar and RSCI (Russian Science Citation Index) for 2007 - 2018 period.


Author(s):  
T. A. Welton

Various authors have emphasized the spatial information resident in an electron micrograph taken with adequately coherent radiation. In view of the completion of at least one such instrument, this opportunity is taken to summarize the state of the art of processing such micrographs. We use the usual symbols for the aberration coefficients, and supplement these with £ and 6 for the transverse coherence length and the fractional energy spread respectively. He also assume a weak, biologically interesting sample, with principal interest lying in the molecular skeleton remaining after obvious hydrogen loss and other radiation damage has occurred.


Author(s):  
Patricia L. Jansma

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.


Author(s):  
E. R. Macagno ◽  
C. Levinthal

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.


Author(s):  
George C. Ruben ◽  
Kenneth A. Marx

Certain double stranded DNA bacteriophage and viruses are thought to have their DNA organized into large torus shaped structures. Morphologically, these poorly understood biological DNA tertiary structures resemble spermidine-condensed DNA complexes formed in vitro in the total absence of other macromolecules normally synthesized by the pathogens for the purpose of their own DNA packaging. Therefore, we have studied the tertiary structure of these self-assembling torus shaped spermidine- DNA complexes in a series of reports. Using freeze-etch, low Pt-C metal (10-15Å) replicas, we have visualized the microscopic DNA organization of both calf Thymus( CT) and linear 0X-174 RFII DNA toruses. In these structures DNA is circumferentially wound, continuously, around the torus into a semi-crystalline, hexagonal packed array of parallel DNA helix sections.


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