When cultured in medium limited of nitrogen sources, the phytopathogen Ustilago maydis produces two amphipathic glycolipids: Ustilagic acid (UA) and Mannosylerythritol lipid (MEL), which in addition to the hydrophilic...When cultured in medium limited of nitrogen sources, the phytopathogen Ustilago maydis produces two amphipathic glycolipids: Ustilagic acid (UA) and Mannosylerythritol lipid (MEL), which in addition to the hydrophilic moiety, contain dior tri-hydroxylated C16 fatty acids (UA), or C8 and C16 saturated fatty acids (MEL). We compared the growth and morphology of cells in YPD and in minimum media containing glucose and nitrogen sources such as nitrate or urea and those deprived of nitrogen. Nitrogen-starved cells showed a dramatic accumulation of internal lipids identified as lipid droplets when stained with the hydrophobic probe BODIPY;these lipid droplets were enriched in unsaturated fatty acids. Fatty acids in YPD or medium containing nitrate as nitrogen source showed a combination of saturated/unsaturated lipids, but when urea was the nitrogen source, cells only contained saturated fatty acids. The glycolipid profiles produced in the presence or absence of nitrogen showed preferences towards the production of one kind of glycolipid: cells in media containing nitrate or urea produced different proportions of UA/MEL, but under nitrogen starvation cells contained only UA. The emulsification capacity of the glycolipids produced in media with or without nitrogen was similar (72% - 76%). HPLC of the glycolipids allowed the separation of fractions with different emulsifying characteristics. Our results indicate that U. maydis accumulates lipid droplets when deprived of nitrogen source and confirm that UA is not under nitrogen control, but rather that MEL and lipid droplets are produced and oppositely regulated by nitrogen.展开更多
A forest plantation, product of the reforestation of pine trees, represented a pool of biological resources for the implementation of a solid state fermentation process. The trees were identified as Pinus pseudostrobu...A forest plantation, product of the reforestation of pine trees, represented a pool of biological resources for the implementation of a solid state fermentation process. The trees were identified as Pinus pseudostrobus Lindl from which lignocellulosic material in the form of pine needles was collected. Soil fungi, responsible for plant litter decomposition, were cultured at laboratory conditions and tested for their ability to grow on cellulose and hemicellulose as the sole carbon sources. A fungal strain, belonging to the genus Penicillium, was selected for growing it on pine needles as the substrate in a solid state culture. After following the culture for six days, the newly isolated strain exhibited a much higher capacity for spore production and holocellulose degradation, compared to a purchased strain of Penicillium chrysogenum and two control conditions. This work marks the beginning of future studies focused on commercial applications and represents the first report of a biotechnological process based on pine needles and their degradation by an ascomycetes species belonging to the genus Penicillium.展开更多
At the beginning of 2020, human activities were interrupted by a new virus, identified as SARS-CoV-2, which causes COVID-19 disease. The scientific area was no exception: for a certain period, researchers around the w...At the beginning of 2020, human activities were interrupted by a new virus, identified as SARS-CoV-2, which causes COVID-19 disease. The scientific area was no exception: for a certain period, researchers around the world were forced to leave their laboratories and work remotely. There was a global necessity for finding alternatives focused on generating knowledge and publishing data, so repositories of scientific information, such as databases, represented strong support. In the specific case of life sciences, different strategies allowed rapid compilation of data and its sharing worldwide. Therefore, in this work, the impact of the SARS-CoV-2 pandemic on the amount of peer-reviewed and published papers during COVID-19 times was analyzed along with the role of databases. Our results pointed out that an increase in the number of papers belonging to different knowledge fields took place, with the medical field being the most significant. On the other hand, the complete genome of the new virus was sequenced, and repositories were created with sufficient data for monitoring, preventing, and controlling its dissemination. This was the case for the generation of vaccines in addition to potential candidates for drugs against COVID-19. However, although in 2021, vaccines allowed us to gradually return to our activities, databases and the generation of other repositories remain a key point for facing new strains and adapting to a new reality. Finally, this paper discusses joint efforts to tackle the obstacles of the pandemic, not only from a medical but also from the point of view regarding the fight against misinformation.展开更多
文摘When cultured in medium limited of nitrogen sources, the phytopathogen Ustilago maydis produces two amphipathic glycolipids: Ustilagic acid (UA) and Mannosylerythritol lipid (MEL), which in addition to the hydrophilic moiety, contain dior tri-hydroxylated C16 fatty acids (UA), or C8 and C16 saturated fatty acids (MEL). We compared the growth and morphology of cells in YPD and in minimum media containing glucose and nitrogen sources such as nitrate or urea and those deprived of nitrogen. Nitrogen-starved cells showed a dramatic accumulation of internal lipids identified as lipid droplets when stained with the hydrophobic probe BODIPY;these lipid droplets were enriched in unsaturated fatty acids. Fatty acids in YPD or medium containing nitrate as nitrogen source showed a combination of saturated/unsaturated lipids, but when urea was the nitrogen source, cells only contained saturated fatty acids. The glycolipid profiles produced in the presence or absence of nitrogen showed preferences towards the production of one kind of glycolipid: cells in media containing nitrate or urea produced different proportions of UA/MEL, but under nitrogen starvation cells contained only UA. The emulsification capacity of the glycolipids produced in media with or without nitrogen was similar (72% - 76%). HPLC of the glycolipids allowed the separation of fractions with different emulsifying characteristics. Our results indicate that U. maydis accumulates lipid droplets when deprived of nitrogen source and confirm that UA is not under nitrogen control, but rather that MEL and lipid droplets are produced and oppositely regulated by nitrogen.
文摘A forest plantation, product of the reforestation of pine trees, represented a pool of biological resources for the implementation of a solid state fermentation process. The trees were identified as Pinus pseudostrobus Lindl from which lignocellulosic material in the form of pine needles was collected. Soil fungi, responsible for plant litter decomposition, were cultured at laboratory conditions and tested for their ability to grow on cellulose and hemicellulose as the sole carbon sources. A fungal strain, belonging to the genus Penicillium, was selected for growing it on pine needles as the substrate in a solid state culture. After following the culture for six days, the newly isolated strain exhibited a much higher capacity for spore production and holocellulose degradation, compared to a purchased strain of Penicillium chrysogenum and two control conditions. This work marks the beginning of future studies focused on commercial applications and represents the first report of a biotechnological process based on pine needles and their degradation by an ascomycetes species belonging to the genus Penicillium.
文摘At the beginning of 2020, human activities were interrupted by a new virus, identified as SARS-CoV-2, which causes COVID-19 disease. The scientific area was no exception: for a certain period, researchers around the world were forced to leave their laboratories and work remotely. There was a global necessity for finding alternatives focused on generating knowledge and publishing data, so repositories of scientific information, such as databases, represented strong support. In the specific case of life sciences, different strategies allowed rapid compilation of data and its sharing worldwide. Therefore, in this work, the impact of the SARS-CoV-2 pandemic on the amount of peer-reviewed and published papers during COVID-19 times was analyzed along with the role of databases. Our results pointed out that an increase in the number of papers belonging to different knowledge fields took place, with the medical field being the most significant. On the other hand, the complete genome of the new virus was sequenced, and repositories were created with sufficient data for monitoring, preventing, and controlling its dissemination. This was the case for the generation of vaccines in addition to potential candidates for drugs against COVID-19. However, although in 2021, vaccines allowed us to gradually return to our activities, databases and the generation of other repositories remain a key point for facing new strains and adapting to a new reality. Finally, this paper discusses joint efforts to tackle the obstacles of the pandemic, not only from a medical but also from the point of view regarding the fight against misinformation.
