Biology subjects

Oliveira, D. F.

Publications and source records attributed to Oliveira, D. F..

4 recordsLinked to original sources

bioRxiv2025

A test of long-term and dose-dependent effects of fluoxetine exposure on the velocity of the invasive crayfish Procambarus clarkii

Fluoxetine, a selective serotonin reuptake inhibitor (SSRI), is one of the most detected antidepressants in wastewater, managing to enter watersheds where it is taken up by freshwater fauna. Here we asked if the serotonergic system affects the dispersal capabilities of Procambarus clarkii, a prolific worldwide invasive freshwater crayfish species, thanks in part due to its dispersal rates. For this, we exposed adult crayfish to fluoxetine (serotonin facilitator) and para-chlorophenylalanine (PCPA, serotonin inhibitor) at two concentrations, and measured their velocity after 8 and 16 days, on a two-meter-long metal gutter. Overall, our treatment effects revealed to be non-significant, however the lowest dosage of fluoxetine seem to decrease crayfish mean velocity between the 8th and 16th day of exposure, thus shedding some light on the putative importance of the long-term exposure to environment dosage-dependent fluoxetine in modulating the dispersal capabilities of P. clarkii. Though further research is needed, these results can help us better understand the impact of ambient fluoxetine to this invasive species.

neuroscience↗

bioRxiv2025

The role of social-environmental factors on Procambarus clarkii dispersion capabilities

Procambarus clarkii is a prominent example of a successful invasive species, and its ability to disperse is known to be a key characteristic. The ability to disperse dictates the spread and impacts an invasive species has, with various known factors influencing it, such as temperature and circadian rhythms. However, there is still limited information on how crayfish social interactions influence their dispersion, and even already known factors still require further investigation. As such, the goal of this study is to deepen the knowledge of the Procambarus clarkii dispersion capabilities. To achieve this, two laboratory experiments were conducted to address the crayfish dispersal abilities, namely their speed, under controlled conditions. The first experiment tested the effect of the interaction of two temperatures (16{degrees}C and 22{degrees}C) and the presence or absence of food in a fully lit or darkened room. The second experiment tested the effects of pairing individuals of the same and opposite sex and of different and/or similar sizes. Three velocity values were obtained: the first considered the crayfishs final position on the track, the second considered the crayfishs furthest point on the track, and finally, the third considered the total distance travelled by the crayfish. Results show that when exposed to the higher temperature and in the absence of food, crayfish increased their speed, but size and sex did not seem to have an effect overall. When paired, female crayfish that were behind another crayfish achieved faster speeds on average than males in the same position. We also found that smaller females had faster velocities when paired with bigger females than with bigger males. The observed increase in speed with higher temperatures suggests that, in the face of current global and habitat changes, P. clarkiis rate of spread may accelerate. However, if provided with a reliable food source, crayfish may disperse less. Still, more research is needed to expand our understanding of which factors contribute to P. clarkiis dispersion capabilities, as this may prove important in formulating new plans and strategies to limit its impacts.

animal behavior and cognition↗

bioRxiv2021

Paving the way towards understanding the inflammatory pathways triggered by giant viruses in mammalian cells: effect of mimivirus-cell interactions on IκBα degradation

Even after two decades since the identification of the first giant virus, the Acanthamoeba polyphaga mimivirus (APMV), it still elude scientists. Their gigantic size and genome are unique in the whole virosphere, and many aspects of their biology are still unknown, including their possible hosts. They are cultivated in laboratories using Acanthamoeba cells as hosts, but little is known about the infectivity of these giant viruses in vertebrate cells. However, there is evidence of the possible involvement of APMV in pneumonia and activation of inflammatory pathways. Among the hundreds of prospected giant viruses members is Tupanvirus, isolated in Brazil. Its particles have a characteristically large size varying between 1.2 to 2 m and are covered by fibrils. In the present work, we aim to study the consequences of the incubation of APMV and Tupanvirus with mammalian cells. These cells express Toll-like receptors (TLR) that are capable of recognizing lipopolysaccharides, favoring the internalization of the antigen and activation of the inflammatory system. We used a lineage of human lung adenocarcinoma cells (A549) to evaluate possible effects of TLR activation by the giant viruses and if we could detect the probable cause of the said giant-virus dependent pneumonia. Our results show that APMV and Tupanvirus (TPV) activate cellular receptors related to the Toll-like 4 type-induced inflammatory response and that the A549 cells are capable of internalizing the latter virus. Therefore, this study brings new insights into the possible interactions established between mimiviruses (here represented by APMV and Tupanvirus) and members of the innate cellular immune response.

microbiology↗

bioRxiv2021

MS-driven metabolic alterations are recapitulated in iPSC-derived astrocytes

ObjectiveAstrocytes play a significant role in the pathology of Multiple Sclerosis (MS). Nevertheless, for ethical reasons, most of the studies in these cells were performed on the Experimental Autoimmune Encephalomyelitis model. As there are significant differences between human and mouse cells, we aimed here to better characterize astrocytes from patients with MS (PwMS), focusing mainly on mitochondrial function and cell metabolism. MethodsWe obtained and characterized induced pluripotent stem cell (iPSC)-derived astrocytes from three PwMS and three unaffected controls and performed functional assays including electron microscopy, flow cytometry, cytokine measurement, gene expression, in situ respiration, and metabolomics. ResultsWe detected several differences in MS astrocytes including: (i) enrichment of genes associated with mitophagy and neurodegeneration, (ii) increased mitochondrial fission and decreased mitochondrial to nuclear DNA ratio, indicating disruption of mitochondrial content, (iii) increased production of superoxide and MS-related proinflammatory chemokines, (iv) increased electron transport capacity and proton leak, in line with the increased oxidative stress, and (v) a distinct metabolic profile, with a deficiency in amino acid catabolism and increased sphingolipid metabolism, which have already been linked to MS. InterpretationTo our knowledge, this is the first study thoroughly describing the metabolic profile of iPSC-derived astrocytes from PwMS, and validating this model as a powerful tool to study disease mechanisms and to perform non-invasive drug targeting assays in vitro. Our findings recapitulate several disease features described in patients and provide new mechanistic insights into the metabolic rewiring of astrocytes in MS, which could be targeted in future therapeutic studies.

neuroscience↗