Comparative highly efficient production of β-glucan by Lasiodiplodia theobromae CCT 3966 and its multiscale characterization

Lasiodiplodan, a (1→6)-β-d-glucan, is an exopolysaccharide with high commercial value and many applications in food, pharmaceuticals, and cosmetics. Current industrial production of β-glucans from crops is mostly by chemical routes generating hazardous and toxic waste. Therefore, alternative sustainable and eco-friendly pathways are highly desirable. Here, we have studied the lasiodiplodan production from sugarcane bagasse (SCB), a major lignocellulosic agricultural residue, by Lasiodiplodia theobromae CCT 3966. Lasiodiplodan accumulated on SCB hydrolysate (carbon source) supplemented with soybean bran or rice bran (nitrogen source) was 16.2 [6.8 × 103 Da] and 22.0 [7.6 × 103 Da] g/L, respectively. Lasiodiplodan showed high purity, low solubility, pseudoplastic behavior and was composed of glucose units. Moreover, the exopolysaccharides were substantially amorphous with moderate thermal stability and similar degradation temperatures. To our knowledge, this is the first report on the highest production of SCB-based lasiodiplodan to date. L. theobromae, as a microbial cell factory, demonstrated the commercial potential for the sustainable production of lasiodiplodan from renewable biomass feedstock

Tuning the magnetic properties of NiPS3through organic-ion intercalation

Atomically thin van der Waals magnetic crystals are characterized by tunable magnetic properties related to their low dimensionality. While electrostatic gating has been used to tailor their magnetic response, chemical approaches like intercalation remain largely unexplored. Here, we demonstrate the manipulation of the magnetism in the van der Waals antiferromagnet NiPS3 through the intercalation of different organic cations, inserted using an engineered two-step process. First, the electrochemical intercalation of tetrabutylammonium cations (TBA+) results in a ferrimagnetic hybrid compound displaying a transition temperature of 78 K, and characterized by a hysteretic behavior with finite remanence and coercivity. Then, TBA+ cations are replaced by cobaltocenium via an ion-exchange process, yielding a ferrimagnetic phase with higher transition temperature (98 K) and higher remanent magnetization. Importantly, we demonstrate that the intercalation and cation exchange processes can be carried out in bulk crystals and few-layer flakes, opening the way to the integration of intercalated magnetic materials in devices.The authors acknowledge R. Llopis and A. Eleta for technical support. This work is supported by “la Caixa” Foundation (ID 100010434), under the agreement LCF/BQ/PI19/11690017, by the Spanish MICINN under Project PID2019-108153GA-I00, RTI2018-094861-B-100 and under the María de Maeztu Units of Excellence Program (MDM-2016-0618). B. M.-G. thanks Gipuzkoa Council (Spain) in the frame of Gipuzkoa Fellows Program.Peer reviewe

Loss of Genetic Redundancy in Reductive Genome Evolution

Biological systems evolved to be functionally robust in uncertain environments, but also highly adaptable. Such robustness is partly achieved by genetic redundancy, where the failure of a specific component through mutation or environmental challenge can be compensated by duplicate components capable of performing, to a limited extent, the same function. Highly variable environments require very robust systems. Conversely, predictable environments should not place a high selective value on robustness. Here we test this hypothesis by investigating the evolutionary dynamics of genetic redundancy in extremely reduced genomes, found mostly in intracellular parasites and endosymbionts. By combining data analysis with simulations of genome evolution we show that in the extensive gene loss suffered by reduced genomes there is a selective drive to keep the diversity of protein families while sacrificing paralogy. We show that this is not a by-product of the known drivers of genome reduction and that there is very limited convergence to a common core of families, indicating that the repertoire of protein families in reduced genomes is the result of historical contingency and niche-specific adaptations. We propose that our observations reflect a loss of genetic redundancy due to a decreased selection for robustness in a predictable environment

Chd8 mediates cortical neurogenesis via transcriptional regulation of cell cycle and Wnt signaling

De novo mutations in CHD8 are strongly associated with autism spectrum disorder, but the basic biology of CHD8 remains poorly understood. Here we report that Chd8 knockdown during cortical development results in defective neural progenitor proliferation and differentiation that ultimately manifests in abnormal neuronal morphology and behaviors in adult mice. Transcriptome analysis revealed that while Chd8 stimulates the transcription of cell cycle genes, it also precludes the induction of neural-specific genes by regulating the expression of PRC2 complex components. Furthermore, knockdown of Chd8 disrupts the expression of key transducers of Wnt signaling, and enhancing Wnt signaling rescues the transcriptional and behavioral deficits caused by Chd8 knockdown. We propose that these roles of Chd8 and the dynamics of Chd8 expression during development help negotiate the fine balance between neural progenitor proliferation and differentiation. Together, these observations provide new insights into the neurodevelopmental role of Chd8.National Institutes of Health (U.S.) (Grant UH1-MH106018-03

Nycthemeral and Monthly Occupation of the Fish Assemblage on a Sheltered Beach of Baía Norte, Florianópolis, Santa Catarina State, Brazil

Interpreting fish community records is challenging for several reasons, including the lack of past ichthyofauna data, the cyclical temporal variations in the community, and the methodology employed, which usually underestimates fish assemblages. The objective of this study was to describe short-scale and meso-scale (nycthemeral period and months, respectively) temporal variations in the ichthyofauna composition and structure of a sheltered beach of Baía Norte (Florianópolis, Santa Catarina state, Brazil), using a capéchade net. Samples were collected monthly for a period of 48 hours. During the period from December 2010 to November 2011, a total of 19,302 individuals belonging to 89 species and 39 families were captured. The number of individuals that were sampled during the day and/or night was dependent on the sampling month. On average, the daytime assemblage was more abundant and different in structure and composition than the nighttime assemblage. Of the eight species that had the highest Index of Relative Importance (%IRI), five had higher variations (ANOVA F) between the day and night than between the months. This finding reinforced the need for sampling during both the day and night. The capéchade net effectively captured demersal and pelagic individuals in a broad range of sizes