1,721,085 research outputs found
The Effects of Temperature Variation on the Sensitivity to Pesticides: a Study on the Slime Mould Dictyostelium discoideum (Protozoa)
No full textSlime moulds live in agricultural ecosystems, where they play an important role in the soil fertilization and in the battle against crop pathogens. In an agricultural soil, the amoebae are exposed to different stress factors such as pesticides and weather conditions. The use of pesticides increased up from 0.49 kg per hectare in 1961 to 2 kg in 2004, and the global greenhouse gas emission has grown 70 % between 1970 and 2004 leading to a global fluctuation of average surface temperature. Therefore, the European Directive 2009/128/EC has led to a new approach to agriculture, with the transition from an old concept based on high use of pesticides and fossil fuels to an agriculture aware of biodiversity and health issues. We studied the effects of temperature variations and pesticides on Dictyostelium discoideum. We measured the fission rate, the ability to differentiate and the markers of stress such as the activity and presence of pseudocholinesterase and the presence of heat shock protein 70. Our results highlight how the sensitivity to zinc, aluminium, silver, copper, cadmium, mercury, diazinon and dicofol changes for a 2 °C variation from nothing/low to critical. Our work suggests considering, in future regulations, about the use of pesticides as their toxic effect on non-target organisms is strongly influenced by climate temperatures. In addition, there is a need for a new consideration of the protozoa, which takes into account recent researches about the presence in this microorganism of classical neurotransmitters that, similar to those in animals, make protozoa an innocent target of neurotoxic pesticides in the battle against the pest crops
La colinesterasi in Dictyostelium discoideum: dalla ricerca di base all'indagine eco-tossicologica.
No full textDevelopment of a laboratory test for the identification of pesticides in food destined for infants: assessment of neurotoxic effects.
No full textIl contributo agli studi ecologici dell'identificazione nei Protozoi di molecole deputate alla neurotrasmissione: il modello Dictyostelium discoideum
No full textNumerosi organismi sono stati proposti negli ultimi decenni come modelli
alternativi alla sperimentazione animale per la valutazione degli effetti di
alterazioni ambientali. In questo contesto i protozoi grazie alla loro natura di
singola cellula eucariote/organismo rappresentano dei modelli sperimentali bioetici
che rispondono alle richieste delle strategie 3Rs. I protozoi sono eccellenti saggi di
laboratorio in quanto: i) come singole cellule espongono direttamente i loro
recettori nell’ambiente circostante risultando sensibili alle modificazioni
ambientali; ii) come organismi rispondono direttamente agli stimoli ambientali
comportandosi al pari degli animali come unità di selezione; iii) hanno brevi cicli
cellulari che consentono di analizzare in un breve tempo gli effetti di un inquinante
su un cospicuo numero di cellule, su popolazioni geneticamente omogenee e per
generazioni successive; iv) sono i progenitori dei metazoi e pertanto le loro risposte
sperimentali possono essere correlate a quelle degli animali. È inoltre importante
sottolineare come l’identificazione nei protozoi di molecole deputate alla
neurotrasmissione quale il sistema GABAergico in Paramecium primaurelia e
Dictyostelium discoideum, nitrergico in Paramecium primaurelia, colinergico in
Paramecium primaurelia, Dictyostelium discoideum, Euplotes crassus, con
caratteristiche simili a quelle dei vertebrati apre la via ad un loro nuovo e moderno
utilizzo negli studi ecologici. In questo lavoro verrà evidenziato come
l’identificazione e la caratterizzazione dell’attività della colinesterasi in
Dictyostelium discoideum abbia permesso di inserire tale modello in studi
riguardanti gli effetti dell’inquinamento prodotto da campi elettromagnetici a
bassissima intensità e frequenza (rete luce) su cellule nervose. Le cellule di
Dictyostelium hanno evidenziato come tali frequenze inducano alterazione
dell’attività dell’enzima colinesterasi in modo tempo di esposizione dipendente e
reversibile
The role of the cholinergic neurotransmitter system in cell-cell communication of protozoa. Simposio I - COMUNICAZIONE: DALLE MOLECOLE ALLA VOCE
No full textThe presence of the cholinergic neurotransmitter system (CNS) has also been detected in non-nervous animal cells as well as in organisms lacking nervous system such as plants, fungi and bacteria (ROSHCHINA, 2010). In this report, the results of the identification of CNS molecules in four protozoa, showing different habitats and life cycles, will be compared. Using immunocytochemical, cytochemical, biochemical and electrophoretic techniques the CNS presence has been described in the freshwater ciliate Paramecium primaurelia, in the marine ciliate Euplotes crassus and in the soil amoeba Dictyostelium discoideum. P. primaurelia and E. crassus have a cholinesterase (ChE) related to acetylcholinesterase (AChE) and D. discoideum have a propionilcolinesterasi (PrChE). The characterization of the CNS molecules, in P. primaurelia and in E. crassus, suggests their modulatory role in their sexual reproductive process, similar to that observed in cell-cell interactions of nerve cells or between sperm and oocyte (PIOMBONI et al., 2000), and in D. discoideum a role as adhesion molecule in cell-cell interactions during the aggregative phase of its development cycle, similar to that observed during the process of embryogenesis. In the soil ciliate Colpoda inflata instead, no molecule belonging CNS has been highlighted. The presence of PrChE in a primitive organism, even compared to the ciliate protozoa, such as D. discoideum, supports the TALESA et al. (1990) theory that it would be an ancestral form of ChE from which the AChE derives. Moreover, the similarities between the roles of ChEs observed in protozoa and those observed in higher organisms, not least the human, indicate their ancient function, suggesting that the evolution of ChE would be leaded by adaptive mechanisms related to their role. Of particular interest in this regard the absence of CNS in C. inflate, a protozoa that doesn’t show sexual process or aggregative phases. The identification in unicellular organisms of CNS opens the question about its role not only in the specie-specific cell-cell communication but also among different species and causes a new consideration of protozoa in ecotoxicological studies from non-target to target organisms of neurotoxic pesticides. Finally, the universal character of their occurrence and similarity of functions at cellular level should convince scientists to doubt the name “neurotransmitter” itself and exchange it, for a more wider term such as “biomediator”
Photobiomodulation Affects Key Cellular Pathways of all Life-Forms: Considerations on Old and New Laser Light Targets and the Calcium Issue
No full textAfter 50 years of studies on photobiomodulation (PBM), there is still so much to investigate to understand the laser light-nonplant cells interactions. The current scientific knowledge allows to say that the phenomena induced by PBM are based on cellular pathways that are the key points of cell life. The mitochondria chromophores, also present on the bacterial membrane, the calcium channels, ion that regulates the life-and-death cellular processes, as well as the TRP family, whose genes have been found in protozoa and suggest that its basic mechanism evolved long before the appearance of animals, seem to be elective targets in photobiomodulatory events by wavelengths from 600 up to 980 nm. The ambiguous resulting cellular communication way, mediated by ATP, ROS and/or calcium, leads to cell manipulation, which modifies its metabolism and whose response connects all life-forms from bacteria to vertebrates. Because of the Giano-Bifronte features of ROS and calcium, as well as the fine balance of energetic mitochondrial processes, whose alteration is responsible for several diseases, the PBM can show unpredictable results and it requires scrupulous approach to avoid cellular damages. However, when carefully applied, PBM is able to improve nonhealthy cell's responses and represents a reliable support in human and veterinary medicine
Dictyostelium discoideum: a bioethical model for the study of the effects of extremely low-frequency electromagnetic fields (ELF-EMF).
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