Search results for "Fresh Water"
showing 10 items of 190 documents
Genetic diversity and phenotypic characterization of Iodobacter limnosediminis associated with skin lesions in freshwater fish
2021
The relatively unknown genus Iodobacter sp. has been repeatedly isolated from skin ulcers and saprolegniosis on freshwater fish in Finland, especially farmed salmonids. Genetic characterization verified that all 23 bacterial isolates studied here belonged to the species Iodobacter limnosediminis, previously undescribed from the fish microbiota. Whole-genome pulsed-field gel electrophoresis revealed variability between the I. limnosediminis strains, suggesting that they were most likely of environmental origin. Two I. limnosediminis strains caused lesions in 27%–53% of brown trout (Salmo trutta) injected intramuscularly (p ≤ .05). The lesions represented moderate to severe tissue damage, but…
Axial (apical-basal) expression of pro-apoptotic and pro-survival genes in the lake baikal demosponge Lubomirskia baicalensis.
2006
Like in all other Metazoa, also in sponges (Porifera) proliferation, differentiation, and death of cells are controlled by apoptotic processes, thus allowing the establishment of a Bauplan (body plan). The demosponge Lubomirskia baicalensis from the Lake Baikal is especially suitable to assess the role of the apoptotic molecules, since its grade of construction is highly elaborated into an encrusting base and branches composed of modules lined up along the apical-basal axis. The four cDNAs, ALG-2, BAK, MA-3, and Bcl-2, were isolated from this sponge species. The expression levels of these genes follow characteristic gradients. While the proapoptotic genes are highly expressed at the base of…
Cold stress defense in the freshwater sponge Lubomirskia baicalensis
2007
The endemic freshwater sponge Lubomirskia baicalensis lives in Lake Baikal in winter (samples from March have been studied) under complete ice cover at near 0 degrees C, and in summer in open water at 17 degrees C (September). In March, specimens show high metabolic activity as reflected by the production of gametes. L. baicalensis lives in symbiosis with green dinoflagellates, which are related to Gymnodinium sanguineum. Here we show that these dinoflagellates produce the toxin okadaic acid (OA), which is present as a free molecule as well as in a protein-bound state. In metazoans OA inhibits both protein phosphatase-2A and protein phosphatase-1 (PP1). Only cDNA corresponding to PP1 could …
A direct Capillary Liquid Chromatography with electrochemical detection method for determination of phenols in water samples
2010
A fast and direct method based on the use of Capillary Liquid Chromatography (LC) with electrochemical (EC) detection has been described for phenols pollutants in water samples. Concretely, phenol, o-cresol, 2-chlorophenol and bisphenol A have been selected as target analytes. The combination of Capillary LC with EC detection avoided the necessity of preconcentration steps typically used in environmental analysis. The sample injected volume was 2 μL. The achieved detection limits were between 1 and 2 μg/L and the linear dynamic range was up to 50 μg/L for all studied phenols. The precision and uncertainty were satisfactory. The analysis time per sample was 10 min. The proposed procedure has…
Selective solid-phase extraction of organophosphorus pesticides and their oxon-derivatives from water samples using molecularly imprinted polymer fol…
2020
Abstract A molecularly imprinted polymer was synthesized and characterized to be used as solid-phase extraction sorbent for simultaneous chlorpyrifos and diazinon and their oxon derivatives. Several imprinted polymers were prepared and evaluated in a retention study of these analytes compared with a non-printed polymer. Several parameters affecting the extraction of imprinted polymer such as washing solvent, composition and volume of the eluting solvent and sample volume, were also investigated. Under the optimum conditions, the developed method provided satisfactory limits of detection ranging between 0.07 µg L−1 to 0.12 µg L−1 and the material showed an excellent reusability (> 50 reuses)…
Multi-residue determination of 47 organic compounds in water, soil, sediment and fish—Turia River as case study
2017
A sensitive and reliable method based on solid-liquid extraction (SLE) using McIlvaine-Na2EDTA buffer (pH = 4.5)-methanol and solid-phase extraction (SPE) clean up prior to ultra-high-performance liquid chromatography coupled to tandem mass spectrometry (UHPLC–MS/MS) was applied to determine 47 organic contaminants in fish, soil and sediments. The SPE procedure to clean-up the extracts was also used as extraction method to determine these compounds in water. Recoveries ranged from 38 to 104% for all matrices with RSDs 50% for 36 compounds in front of 9, matrix effect < 20% for 31 compounds against 21, and LOQs <25 ng g−1 for 38 compounds against 22) indicates that the proposed method is mor…
DNA barcodes reveal the presence of the introduced freshwater leechHelobdella europaeain Spain
2013
Abstract We report the finding of the freshwater leech Helobdella europaea in Spain for the first time. Three leech specimens were found attached to the European pond turtle Emys orbicularis. Helobdella europaea is not a blood feeder and, like all members of the genus, feeds on the hemolymph of aquatic invertebrates including snails and worms. Despite the fact that the original geographical distribution or source population of this species is unknown, the close relationship between H. europaea and leeches of the "triserialis" series (sensu Sawyer, 1986) suggests a New World origin. Given its ability to invade and persist in new environments, this leech has been described as a new species by…
Assessment of methodologies and data used to calculate desalination costs
2017
Abstract In desalination, similarly with other industries, the cost of the final product is one of the most important criteria that define the commercial success of a specific technology. Therefore, when new projects are planned or new technologies are proposed, the analysis of the expected costs attracts a lot of attention and is compared to (perceived) costs of state-of-the-art desalination or costs of alternative fresh water supply options. This comparison only makes sense if the cost assessment methodologies are based on the same principles and use common assumptions. This paper assesses: (i) the methodologies used to calculate the water cost; (ii) the boundary conditions and (iii) the …
Phytoplankton communities of polar regions–Diversity depending on environmental conditions and chemical anthropopressure
2015
The polar regions (Arctic and Antarctic) constitute up to 14% of the biosphere and offer some of the coldest and most arid Earth's environments. Nevertheless several oxygenic phototrophs including some higher plants, mosses, lichens, various algal groups and cyanobacteria, survive that harsh climate and create the base of the trophic relationships in fragile ecosystems of polar environments. Ecosystems in polar regions are characterized by low primary productivity and slow growth rates, therefore they are more vulnerable to disturbance, than those in temperate regions. From this reason, chemical contaminants influencing the growth of photoautotrophic producers might induce serious disorders…
Polar drug residues in sewage and natural waters in the state of Rio de Janeiro, Brazil
1999
The drug residues of lipid regulators, anti-inflammatories and some drug metabolites have been detected in raw sewage, treated waste water and river water in the state of Rio de Janeiro, Brazil. These residues are mainly derived from humans via excretion. The median concentrations in the effluents of sewage treatment plants (STPs) of most drugs investigated in this study ranged from 0.1 to 1 microgram/l. The removal rates of individual drugs during passage through a Brazilian STP varied from 12 to 90%. As a consequence of the incomplete removal of these residues during passage through a STP, rivers were also found to be contaminated. Median concentrations ranged from between 0.02 and 0.04 m…