Search results for "toksiinit"
showing 10 items of 11 documents
Social information use about novel aposematic prey is not influenced by a predator’s previous experience with toxins
2019
Aposematism is an effective antipredator strategy. However, the initial evolution and maintenance of aposematism are paradoxical because conspicuous prey are vulnerable to attack by naive predators. Consequently, the evolution of aposematic signal mimicry is also difficult to explain. The cost of conspicuousness can be reduced if predators learn about novel aposematic prey by observing another predator's response to that same prey. On the other hand, observing positive foraging events might also inform predators about the presence of undefended mimics, accelerating predation on both mimics and their defended models. It is currently unknown, however, how personal and social information combi…
Bioaccumulation of hepatotoxins : A considerable risk in the Latvian environment
2014
Abstract The Gulf of Riga, river Daugava and several interconnected lakes around the City of Riga, Latvia, form a dynamic brackish-freshwater system favouring occurrence of toxic cyanobacteria. We examined bioaccumulation of microcystins and nodularin-R in aquatic organisms in Latvian lakes, the Gulf of Riga and west coast of open Baltic Sea in 2002–2007. The freshwater unionids accumulated toxins efficiently, followed by snails. In contrast, Dreissena polymorpha and most lake fishes (except roach) accumulated much less hepatotoxins. Significant nodularin-R concentrations were detected also in marine clams and flounders. No transfer of nodularin-R and microcystins between lake and brackish …
The Biosynthesis of Rare Homo-Amino Acid Containing Variants of Microcystin by a Benthic Cyanobacterium
2019
Microcystins are a family of chemically diverse hepatotoxins produced by distantly related cyanobacteria and are potent inhibitors of eukaryotic protein phosphatases 1 and 2A. Here we provide evidence for the biosynthesis of rare variants of microcystin that contain a selection of homo-amino acids by the benthic cyanobacterium Phormidium sp. LP904c. This strain produces at least 16 microcystin chemical variants many of which contain homophenylalanine or homotyrosine. We retrieved the complete 54.2 kb microcystin (mcy) gene cluster from a draft genome assembly. Analysis of the substrate specificity of McyB1 and McyC adenylation domain binding pockets revealed divergent substrate specificity …
Effects of fumonisin B1 on performance of juvenile Baltic salmon (Salmo salar)
2013
Fumonisin B1 is a mycotoxin produced by fungi of the genus Fusarium that frequently occurs on maize (Zea mays) and feeds containing it. The use of plant-based protein sources in feeds designed for aquaculture has increased due to their low costs compared with fishmeal. This trend has resulted in a global increase in feed formulations contaminated with mycotoxins, producing economical losses in aquaculture industry. The topic also causes concerns because of the potential health consequences that aquaculture products could have on human consumers. FB1 mainly disrupts sphingolipid metabolism and also has immune suppressive effects. Fish mycotoxicosis produces a wide range of symptoms from poor…
Cyanobacteria and their metabolites in mono- and polidominant shallow eutrophic temperate lakes
2022
Monodominant (one species dominates) or polidominant (multiple species dominate) cyanobacterial blooms are pronounced in productive freshwater ecosystems and pose a potential threat to the biota due to the synthesis of toxins. Seasonal changes in cyanobacteria species and cyanometabolites composition were studied in two shallow temperate eutrophic lakes. Data on cyanobacteria biomass and diversity of dominant species in the lakes were combined with chemical and molecular analyses of fifteen potentially toxin-producing cyanobacteria species (248 isolates from the lakes). Anatoxin-a, saxitoxin, microcystins and other non-ribosomal peptides formed the diverse profiles in monodominant (Planktot…
Retene, pyrene and phenanthrene cause distinct molecular-level changes in the cardiac tissue of rainbow trout (Oncorhynchus mykiss) larvae, Part 2 – …
2020
Polycyclic aromatic hydrocarbons (PAHs) are global contaminants of concern. Despite several decades of research, their mechanisms of toxicity are not very well understood. Early life stages of fish are particularly sensitive with the developing cardiac tissue being a main target of PAHs toxicity. The mechanisms of cardiotoxicity of the three widespread model polycyclic aromatic hydrocarbons (PAHs) retene, pyrene and phenanthrene were explored in rainbow trout (Oncorhynchus mykiss) early life stages. Newly hatched larvae were exposed to sublethal doses of each individual PAH causing no detectable morphometric alterations. Changes in the cardiac proteome and metabolome were assessed after 7 o…
Effects of waste treatment technique and quality of waste on bioaerosols in Finnish waste treatment plants
2004
Outi Tolvanen selvitti tutkimuksessaan mikrobi-, endotoksiini- ja pölypitoisuuksia suomalaisilla jätteenkäsittelylaitoksilla. Tolvanen tutki, onko jätteiden tehostunut syntypistelajittelu ja jätteiden käsittely suljetuissa laitoksissa vähentänyt bioaerosolien ja pölyn aiheuttamia työhygieenisiä ongelmia. Kohonneiden mikrobipitoisuuksien on aikaisemmissa tutkimuksissa havaittu aiheuttavan jätteitä työssään käsitteleville henkilöille erilaisia oireita, kuten pahoinvointia, päänsärkyä, kuumeilua sekä allergiaa ja astmaa. The last fifteen years have seen immense changes in waste treatment in Finland. The number of landfill sites has been reduced and new waste treatment plants have been construc…
Retene, pyrene and phenanthrene cause distinct molecular-level changes in the cardiac tissue of rainbow trout (Oncorhynchus mykiss) larvae, part 1 – …
2020
Polycyclic aromatic hydrocarbons (PAHs) are contaminants of concern that impact every sphere of the environment. Despite several decades of research, their mechanisms of toxicity are still poorly understood. This study explores the mechanisms of cardiotoxicity of the three widespread model PAHs retene, pyrene and phenanthrene in the rainbow trout (Oncorhynchus mykiss) early life stages. Newly hatched larvae were exposed to each individual compound at sublethal doses causing no significant increase in the prevalence of deformities. Changes in the cardiac transcriptome were assessed after 1, 3, 7 and 14 days of exposure using custom Salmo salar microarrays. The highest number of differentiall…
Alterations in Daphnia magna exposed to enniatin B and beauvericin provide additional value as environmental indicators
2022
Mycotoxins beauvericin (BEA) and enniatin B (ENN B) affect negatively several systems and demand more studies as the mechanisms are still unclear. The simultaneous presence of contaminants in the environment manifests consequences of exposure for both animals and flora. Daphnia magna is considered an ideal invertebrate to detect effects of toxic compounds and environmental alterations. In this study, the potential toxicity and the basic mechanism of BEA and ENN B individually and combined were studied in D. magna. Acute and delayed toxicity were evaluated, and transcript levels of genes involved in xenobiotic metabolism (mox, gst, abcb1, and abcc5), reproduction, and oxidative stress (vtg-S…
The effects of dietary fumonisin B1 on growth and physiology of rainbow trout (Oncorhynchus mykiss)
2016
Kalanrehuissa on perinteisesti luotettu kalajauhoon ja -öljyyn rehujen pääasiallisina proteiinin- ja energianlähteinä. Näitä raaka-aineita on nykyään alettu korvata kasviperäisillä ainesosilla niiden edullisemman hinnan ja helpomman saatavuuden vuoksi, esimerkiksi maissilla, vehnällä ja soijalla. Pilaantuneen kasviperäisen raaka-aineen mukana rehuun pääsee haitallisia mykotoksiineja. Mykotoksiinit ovat homesienten sekundäärisiä metaboliatuotteita, joita ne pääasiassa tuottavat kilpailuun muita homeita vastaan, ja joiden on havaittu aiheuttavan kasvun heikentymistä ja sairauksia monilla eri kotieläimillä, mutta niiden vaikutuksista kaloihin tiedetään varsin vähän. Yksi yleisimmistä mykotoksi…