Unconventional Pathways of Protein Secretion: Mammals vs. Plants

none6noIn eukaryotes, many proteins contain an N-terminal signal peptide that allows their translocation into the endoplasmic reticulum followed by secretion outside the cell according to the classical secretory system. However, an increasing number of secreted proteins lacking the signal peptide sequence are emerging. These proteins, secreted in several alternative ways collectively known as unconventional protein secretion (UPS) pathways, exert extracellular functions including cell signaling, immune modulation, as well as moonlighting activities different from their well-described intracellular functions. Pathways for UPS include direct transfer across the plasma membrane, secretion from endosomal/multivesicular body-related components, release within plasma membrane-derived microvesicles, or use of elements of autophagy. In this review we describe the mammals and plants UPS pathways identified so far highlighting commonalities and differencesopenElisa Maricchiolo, Eleonora Panfili, Andrea Pompa, Francesca De Marchis, Michele Bellucci, Maria Teresa PallottaMaricchiolo, Elisa; Panfili, Eleonora; Pompa, Andrea; De Marchis, Francesca; Bellucci, Michele; Teresa Pallotta, Mari

Towards microalga-based superfoods: heterologous expression of zeolin in Chlamydomonas reinhardtii

Microalgae are unicellular photosynthetic organisms that can be grown in artificial systems to capture CO2, release oxygen, use nitrogen- and phosphorus-rich wastes, and produce biomass and bioproducts of interest including edible biomass for space exploration. In the present study, we report a metabolic engineering strategy for the green alga Chlamydomonas reinhardtii to produce high-value proteins for nutritional purposes. Chlamydomonas reinhardtii is a species approved by the U.S. Food and Drug Administration (FDA) for human consumption, and its consumption has been reported to improve gastrointestinal health in both murine models and humans. By utilizing the biotechnological tools available for this green alga, we introduced a synthetic gene encoding a chimeric protein, zeolin, obtained by merging the γ-zein and phaseolin proteins, in the algal genome. Zein and phaseolin are major seed storage proteins of maize (Zea mays) and bean (Phaseolus vulgaris) that accumulate in the endoplasmic reticulum (ER) and storage vacuoles, respectively. Seed storage proteins have unbalanced amino acid content, and for this reason, need to be complemented with each other in the diet. The chimeric recombinant zeolin protein represents an amino acid storage strategy with a balanced amino acid profile. Zeolin protein was thus efficiently expressed in Chlamydomonas reinhardtii; thus, we obtained strains that accumulate this recombinant protein in the endoplasmic reticulum, reaching a concentration up to 5.5 fg cell-1, or secrete it in the growth medium, with a titer value up to 82 µg/L, enabling the production of microalga-based super-food

Bioconversion of Callus-Produced Precursors to Silymarin Derivatives in Silybum marianum Leaves for the Production of Bioactive Compounds.

Gad D, El-Shora H, Fraternale D, Maricchiolo E, Pompa A, Dietz K-J. Bioconversion of Callus-Produced Precursors to Silymarin Derivatives in Silybum marianum Leaves for the Production of Bioactive Compounds. International journal of molecular sciences. 2021;22(4): 2149.The present study aimed to investigate the enzymatic potential of Silybum marianum leaves to bioconvert phenolic acids produced in S. marianum callus into silymarin derivatives as chemopreventive agent. Here we demonstrate that despite the fact that leaves of S. marianum did not accumulate silymarin themselves, expanding leaves had the full capacity to convert di-caffeoylquinic acid to silymarin complex. This was proven by HPLC separations coupled with electrospray ionization mass spectrometry (ESI-MS) analysis. Soaking the leaf discs with S. marianum callus extract for different times revealed that silymarin derivatives had been formed at high yield after 16 h. Bioconverted products displayed the same retention time and the same mass spectra (MS or MS/MS) as standard silymarin. Bioconversion was achieved only when using leaves of a specific age, as both very young and old leaves failed to produce silymarin from callus extract. Only medium leaves had the metabolic capacity to convert callus components into silymarin. The results revealed higher activities of enzymes of the phenylpropanoid pathway in medium leaves than in young and old leaves. It is concluded that cotyledon-derived callus efficiently produces compounds that can be bio-converted to flavonolignans in leaves tissue of S. marianum

Nanovesicles from plant cells as a new challenge in drug delivery systems

Background: Recently, pharmaceutical technology linked to drug delivery is making great strides, in fact, the success of therapy is now closely related to the delivery system of bioactive compounds. In the field of drug delivery, nanovesicles of biological origin seem to be the most promising, and certainly, plant-derived nanovesicles are one of the most studied actors. Plant-derived nanovesicles are usually obtained by more or less strong homogenization of vegetable matrices and subsequent purification. Here we proposed a new method for the recovery of actively secreted plant-derived extracellular vesicles (EVs) from the culture medium. Aim: Our research aims to build a biotechnological platform based on plant matrices for the production of nanovesicles suitable for drug delivery. Methods: Plant cells derived from the enzymatic degradation of the cell wall of tobacco leaves and cauliflower were isolated and cultured in a suitable liquid culture medium. The culture liquid was harvested every day for three days and subjected to differential centrifugations to purify secreted extracellular vesicles. The samples obtained were analyzed both with nanoparticle tracking assay and transmission electron microscope. Finally, the purified EVs were used in an in vitro assay to evaluate anti-inflammatory properties. Preliminary Results: Preliminary experiments demonstrate that tobacco and cauliflower cells actively release EVs-like particles in the extracellular space. Furthermore, functional experiments carried out on activated THP-1 cells showed that the mere presence of nanovesicles of plant origin has a positive effect leading to the reduction of inflammatory cytokine expression These results suggest a possible use of nanovesicles extracted from cell culture media in the medical field. Conclusions: Nanovesicles of vegetable origin can represent an alternative to those of animal or synthetic origin in drug delivery technology. Pathogens that attack plants are unable to infect humans and therefore pharmaceutical preparations using plant cells are safe and less expensive to produce

A biotechnological approach for the production of new protein bioplastics

The future of biomaterial production will leverage biotechnology based on the domestication of cells as biological factories. Plants, algae and bacteria can produce low-environmental impact biopolymers. Here, we have developed two strategies to produce a biopolymer derived from a bioengineered vacuolar storage protein of the common bean (phaseolin; PHSL). The cys-added PHSL* forms linear-structured biopolymers when expressed in the thylakoids of transplastomic tobacco leaves by exploiting the formation of inter-chain disulfide bridges. The same protein without signal peptide (ΔPHSL*) accumulates in E. coli inclusion bodies as high-molar-mass species polymers that can subsequently be oxidized to form disulfide crosslinking bridges in order to increase the stiffness of the biomaterial, a valid alternative to the use of chemical crosslinkers. The E. coli cells produced 300 times more engineered PHSL, measured as percentage of total soluble proteins, than transplastomic tobacco plants. Moreover, the thiol groups of cysteine allow the site-specific PEGylation of ΔPHSL*, which is a desirable functionality in the design of a protein-based drug carrier. In conclusion, ΔPHSL* expressed in E. coli has the potential to become an innovative biopolymer

15X15 Nuovi Sguardi su Roma. Letture critiche di architettura contemporanea

Quindici dottorandi di ricerca indagano quindici opere di architettura contemporanea realizzate negli ultimi 10 anni a Roma. Presentano progetti non fra i più noti al grande pubblico, letti attraverso una visione critica che fa conoscere ai Romani la loro città in una veste inaspettata e invita a riflettere sull’importanza della buona architettura e sulle sue potenzialità future

The Synergistic Impacts of Anthropogenic Stressors and COVID-19 on Aquaculture: A Current Global Perspective

The rapid, global spread of COVID-19, and the measures intended to limit or slow its propagation, are having major impacts on diverse sectors of society. Notably, these impacts are occurring in the context of other anthropogenic-driven threats including global climate change. Both anthropogenic stressors and the COVID-19 pandemic represent significant economic challenges to aquaculture systems across the globe, threatening the supply chain of one of the most important sources of animal protein, with potential disproportionate impacts on vulnerable communities. A web survey was conducted in 47 countries in the midst of the COVID-19 pandemic to assess how aquaculture activities have been affected by the pandemic, and to explore how these impacts compare to those from climate change. A positive correlation between the effects of the two categories of drivers was detected, but analysis suggests that the pandemic and the anthropogenic stressors affect different parts of the supply chain. The immediate measurable reported losses varied with aquaculture typology (land vs. marine, and intensive vs. extensive). A comparably lower impact on farmers reporting the use of integrated multitrophic aquaculture (IMTA) methods suggests that IMTA might enhance resilience to multiple stressors by providing different market options under the COVID-19 pandemic. Results emphasize the importance of assessing detrimental effects of COVID-19 under a multiple stressor lens, focusing on areas that have already locally experienced economic loss due to anthropogenic stressors in the last decade. Holistic policies that simultaneously address other ongoing anthropogenic stressors, rather than focusing solely on the acute impacts of COVID-19, are needed to maximize the long-term resilience of the aquaculture sector.publishedVersio

The Synergistic Impacts of Anthropogenic Stressors and COVID-19 on Aquaculture: A Current Global Perspective

The rapid, global spread of COVID-19, and the measures intended to limit or slow its propagation, are having major impacts on diverse sectors of society. Notably, these impacts are occurring in the context of other anthropogenic-driven threats including global climate change. Both anthropogenic stressors and the COVID-19 pandemic represent significant economic challenges to aquaculture systems across the globe, threatening the supply chain of one of the most important sources of animal protein, with potential disproportionate impacts on vulnerable communities. A web survey was conducted in 47 countries in the midst of the COVID-19 pandemic to assess how aquaculture activities have been affected by the pandemic, and to explore how these impacts compare to those from climate change. A positive correlation between the effects of the two categories of drivers was detected, but analysis suggests that the pandemic and the anthropogenic stressors affect different parts of the supply chain. The immediate measurable reported losses varied with aquaculture typology (land vs. marine, and intensive vs. extensive). A comparably lower impact on farmers reporting the use of integrated multitrophic aquaculture (IMTA) methods suggests that IMTA might enhance resilience to multiple stressors by providing different market options under the COVID-19 pandemic. Results emphasize the importance of assessing detrimental effects of COVID-19 under a multiple stressor lens, focusing on areas that have already locally experienced economic loss due to anthropogenic stressors in the last decade. Holistic policies that simultaneously address other ongoing anthropogenic stressors, rather than focusing solely on the acute impacts of COVID-19, are needed to maximize the long-term resilience of the aquaculture sector