Functional purification of the monocarboxylate transporter of the yeast Candida utilis

Plasma membranes of the yeast, Candida utilis, were solubilized with octyl-b-D- lucopyranoside and a fraction enriched in the lactate carrier was obtained with DEAE-Sepharose anion- exchange chromatography, after elution with 0.4 M NaCl. The uptake of lactic acid into proteoliposomes, containing the purified protein fraction and cytochrome c oxidase, was dependent on a proton-motive force and the transport specificity was consistent with the one of C. utilis intact cells. Overall, we have obtained a plasma membrane fraction enriched in the lactate carrier of C. utilis in which the transport properties were preserved. Given the similarities between the lactate transport of C. utilis and the one of mammalian cells, this purified system could be further explored to screen for specific lactate inhibitors, with potential therapeutic applications

Plastic interactions with pollutants and consequences to aquatic ecosystems: what we know and what we do not know

Plastics are a group of synthetic materials made of organic polymers and some additives with special characteristics. Plastics have become part of our daily life due to their many applications and uses. However, inappropriately managed plastic waste has raised concern regarding their ecotoxicological and human health risks in the long term. Due to the non-biodegradable nature of plastics, their waste may take several thousands of years to partially degrade in natural environments. Plastic fragments/particles can be very minute in size and are mistaken easily for prey or food by aquatic organisms (e.g., invertebrates, fishes). The surface properties of plastic particles, including large surface area, functional groups, surface topography, point zero charge, influence the sorption of various contaminants, including heavy metals, oil spills, PAHs, PCBs and DDT. Despite the fact that the number of studies on the biological effects of plastic particles on biota and humans has been increasing in recent years, studies on mixtures of plastics and other chemical contaminants in the aquatic environment are still limited. This review aims to gather information about the main characteristics of plastic particles that allow different types of contaminants to adsorb on their surfaces, the consequences of this adsorption, and the interactions of plastic particles with aquatic biota. Additionally, some missing links and potential solutions are presented to boost more research on this topic and achieve a holistic view on the effects of micro- and nanoplastics to biological systems in aquatic environments. It is urgent to implement measures to deal with plastic pollution that include improving waste management, monitoring key plastic particles, their hotspots, and developing their assessment techniques, using alternative products, determining concentrations of micro- and nanoplastics and the contaminants in freshwater and marine food-species consumed by humans, applying clean-up and remediation strategies, and biodegradation strategies.This study was supported by the strategic programme UID/BIA/04050/2019 and the Emergemix project (PTDC/BIABMA/30922/2017) funded by national funds through the Portuguese Foundation for Science and Technology (FCT) I.P. and by the ERDF through the COMPETE2020ProgramaOperacionalCompetitividade e Internacionalizacao

The role of invertebrates and aquatic fungi on the decomposition of eucalyptus leaves in streams

Resumo da comunicação apresentada no XII Congresso da Association Española de Limnología - IV Congresso Ibérico de Limnologia. CIMAR, Universidade do Porto, 5-9 Julho 2004.Leaves entering in streams are subject to physical abrasion, invertebrate fragmentation and microbial degradation. Fungi, particularly aquatic hyphomycetes, dominate microbial leaf decomposition and condition the leaves, increasing their palatability for invertebrate shredders. The aim of this work was to study the relative role of invertebrates and aquatic fungi on leaf decomposition of Eucalyptus globulus Labill. in two rivers of Northwest Portugal with different water chemistry. For that purpose, leaf decomposition was followed in coarse-mesh and fine-mesh bags. Physical, chemical and microbial analyses of the stream water, as well as, biotic indices and diversity measures applied to the invertebrates associated with leaves showed that the Guisande River had better water quality than the Este River. Decomposition rates of eucalyptus leaves were significantly higher in the Guisande River (k = 0.019 to 0.029 dˉ¹) than in the Este River (k = 0.009 to 0.011 dˉ¹). Significantly higher fungal biomass (up to 790 μg ergosterol gˉ¹ AFDM) and sporulation rates (up to 370 conidia mgˉ¹ AFDM dˉ¹) occurred in the Guisande River in comparison with the Este River (fungal biomass up to 280 μg ergosterol gˉ¹ AFDM; sporulation rates up to 90 conidia mgˉ¹ AFDM dˉ¹). Correspondence analyses applied to aquatic hyphomycete and invertebrate assemblages discriminated the two rivers and higher richness in taxa was found in the Guisande River. In this river, leaf decomposition rate was significantly higher in coarse-mesh than in fine-mesh bags. However, in the Este River no significant differences were found between coarse-mesh and fine-mesh bags, which can be attributed to the absence of shredders and low current velocity in this river

Effects of increased temperature and aquatic fungal diversity on litter decomposition

This version thus not correspond to the final version of the journal. To assess the final version please go to: http://www.sciencedirect.com/science/article/pii/S1754504812000876Climate warming and biodiversity loss are two major factors threatening freshwaters. Aquatic hyphomycetes are fungi that play a key role in organic matter turnover in streams. To assess the impacts of temperature increase and aquatic hyphomycete diversity on plant-litter decomposition, we manipulated fungal assemblage composition at two levels of diversity (four and eight species) under ambient temperature of 16 º C and two regimes of temperature increase differing in 8 º C: abrupt versus gradual increase from 16 to 24 º C. The effects were evaluated on leaf-litter decomposition, fungal biomass and reproduction. Results showed faster leaf decomposition under increased temperature, but no differences were found between an abrupt and a gradual increase in temperature. Assemblage composition was the major factor controlling fungal biomass and reproduction, while fungal diversity was only critical to maintain reproduction.Fundação para a Ciência e a Tecnologia (FCT), através dos projectos: PTDC/CLI/67180/2006 (FCOMP-01-0124-FEDER-007112), TDC/AAC-AMB/117068/2010, e PEst-C/BIA/UI4050/2011

Ataque ao Fundeb: intersecções entre ultraliberais e reacionários no projeto de privatização do fundo público

The night of December 10, 2020 must not be forgotten. On that occasion, during the vote on Bill No. 4.372/2020 that regulated the new Fundeb, a proposal to transfer resources from the public fund to private elementary and high schools gained majority support in the Brazilian Chamber of Deputies, in an unprecedented way and contrary to the Brazilian Constitution (1988). In this article, we analyze the factors related to the episode promoted by whom we name as Aloprados do Fundeb, in reference to the recent convergence of privatizationist and reactionary sectors in the Brazilian legislative branch. Special attention is given to the coincidences with the debate that led to the approval of the first Brazilian general law of education (1961), the role played by the party and legislative caucuses active in the 2019-2022 Brazilian legislature, the concertation between neoliberal and reactionary religious sectors interested in accessing public resources and eroding the secular nature of education, as well as the resistance of sectors opposed to privatization that managed to win on that occasion.La noche del 10 de diciembre de 2020 no debe olvidarse. En aquella ocasión, durante la votación del PL n. 4.372/2020 que regulaba el nuevo Fundeb, una propuesta de transferencia de recursos del fondo público a las escuelas primarias y secundarias privadas, contraria a la Constitución de 1988, obtuvo el apoyo mayoritario de la Cámara de Diputados, por primera vez. En el artículo se analizan los factores relacionados con el episodio promovido por los que serán denominados aquí, de forma ensayística, como Aloprados do Fundeb, en referencia a la reciente convergencia de sectores privatistas y reaccionarios en la legislatura brasileña. Se prestará especial atención a las coincidencias con el debate que condujo a la aprobación de la LDB de 1961, al papel jugado por el partido y las bancadas legislativas activas en la legislatura 2019-2022, a la concertación entre neoliberales y corrientes religiosas reaccionarias, interesadas en acceder a los recursos públicos y erosionar la laicidad de la educación, y a la resistencia de los sectores opuestos a la privatización, que lograron vencer en aquella ocasión.A noite de 10 de dezembro de 2020 não deve ser esquecida. Na ocasião, durante a votação do PL n. 4.372/2020 que regulamentou o novo Fundeb, ganhou adesão majoritária na Câmara dos Deputados, de forma inédita, uma proposta de transferência de recursos do fundo público para escolas privadas dos ensinos fundamental e médio, contrariando a Constituição de 1988. No artigo, analisam-se os fatores relacionados ao episódio promovido por quem aqui será denominado, a modo ensaístico, como Aloprados do Fundeb, em remissão à convergência recente de setores privatistas e reacionários no legislativo brasileiro. Atenção especial será dada às coincidências com o debate que levou à aprovação da LDB de 1961, ao papel desempenhado pelas bancadas partidárias e legislativas atuantes na legislatura 2019-2022, à concertação entre neoliberais e vertentes religiosas reacionárias, interessadas em acessar recursos públicos e erodir a laicidade do ensino e a resistência dos setores contrários à privatização, que lograram vencer naquela ocasião

Antagonistic potential of Wickerhamomyces anomalus against phytopathogens causing Olive Anthracnose and Chestnut Ink Disease

Olive Anthracnose (OA) and Chestnut Ink Disease (CID), caused by eukaryotic organisms such as fungi and oomycetes, pose significant challenges to agricultural production, causing severe yield losses and reduced quality of harvested products. Currently, chemical pesticides are widely used to control these pathogens. However, this approach can be expensive and ineffective, and may have detrimental environmental and health effects. Thus, the development of new, greener and more effective strategies is vital for maintaining agricultural productivity and mitigating the impacts of plant diseases and plagues on food supply and economy on Portugal and other producing countries. The use of yeasts as biological control agents is an effective and environmentally friendly alternative approach for controlling plant pathogens. In this work, we explore the potential of Wickerhamomyces anomalus as a living biocontrol agent for the sustainable pre-harvest control of OA and CID, and to unveil its mode of action. We conducted antagonism assays in liquid media, co-culturing the yeast W. anomalus with three strains of Colletotrichum, causing OA, and two strains of Phytophthora, causing CID. The mode of action of W. anomalus was assessed in several aspects. (i) The viability of the mycelia resulting from the co-cultures was evaluated through re-culturing the mycelia and by microscopic inspection of Methylene Blue-staining mycelia. (ii) Additionally, two common biocontrol strategies were tested - the secretion of cell-wall degrading enzymes and siderophores. (iii) Finally, the interactions between yeast and phytopathogens were further investigated through SEM microscopy. Results confirmed the strong ability of W. anomalus to inhibit the growth of both Colletotrichum and Phytophthora strains, although in different manners. We found that (i) the fungal cells were stained with Methylene Blue, indicating cell death, although, at the same time they were all able to grow back in the presence of a reduced number of yeasts, suggesting a dose-dependent effect; and that (ii) enzymatic and siderophore activity was low/absent, indicating little influence in the mode of action. Importantly, we observed the existence of several antagonism-related features, such as coiled and emptied hyphae and yeasts cells inside the hyphae of C. godetiae and P. cinnnamomi. Results suggest that W. anomalus acts as a predatious yeast, using specific strategies according to its target, corroborating this yeast’s potential for field application in phytosanitary control.This work was supported by the “Contrato-Programa” UIDB/04050/2020 funded by national funds through the FCT I.P. M.A.-R. was the recipient of the FCT, I.P. doctoral grant SFRH/BD/145354/201

Are aquatic fungi able to evaluate microplastic impacts on leaf litter decomposition process?

Microplastics (MPs) have been recognized as a threat, and an ecotoxicological risk for aquatic ecosystems. MPs toxicity is determined by their physical and chemical properties, including particle size, shape, surface area or polymer type. Aquatic hyphomycetes are a group of fungi that have the greatest ecological effects on freshwater ecosystems, as they are involved in a key process on these ecosystems, the decomposition of plant litter in streams. These fungi have the ability to degrade and consequently transform leaf material into a more suitable food source for stream detritivores, being important mediators in the energy and nutrient transfer to higher trophic levels. The knowledge on the impacts of MPs on aquatic fungi and the processes they driven is very scarce, so the main goal of this study was to assess the impacts of different sizes of MPs (fragments, FR; and pellets, PE) on the leaf litter decomposition, measuring functional aspects such as leaf mass loss, fungal reproduction and activity of plant litter degrading enzymes. A microcosm experiment was used with monocultures and combinations up to three aquatic hyphomycetes species (Articulospora tetracladia, Tricladium splendens, and Heliscus lugdunensis), where concentrations of FR (0.5 and 2 g L-1) and PE (2 g L-1) were added. We expected that: i) the presence of FR could negatively affect all functional aspects; ii) the impacts of the PE could not be so strong as FR impacts, as PE has a bigger size than FR; iii) the traits of the fungal species would matter to face MP exposure because the traits of certain fungal species may be of greater importance than species number to maintain ecological processes. FR or PE led to a stimulation of leaf mass loss especially in combinations of two aquatic hyphomycetes. Consequently, the activity of degrading enzymes increased in the presence of 0.5 g L-1 FR and PE. Fungal sporulation rate increased in the presence of FR, especially for monocultures and combinations of three aquatic hyphomycetes, while the presence of PE decreased fungal sporulation in combinations of the three aquatic hyphomycetes. Our results showed the MPs influence in the activity and diversity of microbial decomposers, putting at risk the processes they drive in freshwaters. This suggest the aquatic hyphomycetes as potential microorganisms to be used to evaluate the MPs impacts on leaf decomposition process

Impacts of warming on aquatic decomposers along a gradient of cadmium stress

We evaluated the effects of cadmium and temperature on plant-litter decomposition by examining diversity and activity of aquatic fungi and leaf consumption by Limnephilus sp., a typical invertebrate shredder of Iberian streams. Freshly fallen leaves were immersed in a stream to allow microbial colonization, and were exposed in microcosms to a gradient of cadmium (≤11 levels, ≤35 mg L-1 ). Microcosms were kept at 15 ºC, a temperature typically found in Iberian streams in autumn, and at 21 ºC to simulate a warming scenario. The increase in temperature stimulated leaf decomposition by microbes, fungal reproduction and leaf consumption by the shredder. Conversely, increased cadmium concentrations inhibited fungal reproduction and diversity, and leaf consumption by the invertebrate. Cadmium concentration inhibiting 50% of fungal reproduction, microbial decomposition and leaf consumption by the shredder was higher at 15 ºC than at 21 ºC, suggesting that higher temperatures can lead to increased metal toxicity to aquatic decomposers.This study was supported by the Portuguese Foundation for Science and Technology through the projects PTDC/CLI/67180/2006 (FCOMP-01-0124-FEDER-007112) and PEst-C/BIA/UI4050/2011

Nano copper oxide is a threat to an endemic shredder of the Iberian Peninsula

FEDER-POFC-COMPETE and the Portuguese Foundation for Science and Technology supported this study (PEst-C/BIA/UI4050/2011, NANOECOTOX-PTDC/AAC-AMB/121650/2010) and A. Pradhan was supported by the Portuguese Foundation for Science and Technology (SFRH/BD/45614/2008)

Polyhydroxyl fullerene can mitigate toxicity effects of cadmium on yeasts

With inception of nanotechnology, nanomaterials are currently in the prime-line of research. Polyhydroxyl fullerene is one of the widely commercialized nanomaterials and applied in electronics and biomedical fields. Unlike fullerene, polyhydroxyl fullerene is known to be biocompatible, and recent studies reported its antioxidant properties. On the other hand, cadmium toxicity has been often attributed to the ability of this metal to induce oxidative stress. To assess antioxidant properties of polyhydroxyl fullerene, the model yeast Saccharomyces cerevisiae was exposed to cadmium (≤ 5 ppm, 3 levels) in the presence or absence of polyhydroxyl fullerene (≤ 500 ppm, 3 levels) at different pH values (5.8, 6.3 and 6.8). The size distribution and dispersion of polyhydroxyl fullerene in the stock suspension were measured with DLS (z-average 143 nm, PdI 0.365). Yeast growth, plasma membrane integrity and accumulation of reactive oxygen species (ROS) were investigated in the presence or absence of Cd2+ and/or polyhydroxyl fullerene. Yeast growth was inhibited up to 34% by exposure to Cd2+, but was not affected by polyhydroxyl fullerene. At pH 5.8, the exposure to the highest concentration of Cd2+ (5 ppm) and polyhydroxyl fullerene (500 ppm) stimulated yeast growth by 59 and 61% at the exponential and late exponential growth phases, respectively. Growth increased even more when pH increased to 6.8. Severe plasma membrane disruption and ROS accumulation were observed after exposure to the highest concentration of Cd2+ in the absence of polyhydroxyl fullerene. Membrane disruption and ROS accumulation decreased with increasing concentration of polyhydroxyl fullerene and with the increase in pH to 6.8. Overall, results indicated that polyhydroxyl fullerene is not toxic to yeasts and may potentially trigger antioxidant defense mechanisms to mitigate metal-induced toxicity.Funding: FEDER-POFC-COMPETE and FCT supported this study (PEst-C/BIA/UI4050/2011, NANOECOTOX- PTDC/AAC-AMB/121650/2010) and A. Pradhan (SFRH/BD/45614/2008)