Project description:Polyethylene terephthalate (PET) is one of the most commonly used plastics, utilized in synthetic fibers, water containers, and food packaging. From the 1990s onwards, the demand for PET, and therefore its production, increased exponentially. This increased usage of PET has resulted in a staggering accumulation of undegraded plastic waste. Nearly 80% of the 6300 million tons of plastic waste that had been generated as of 2015 were accumulated in landfills or the natural environment. Moreover, the production of PET relies heavily on non‐renewable fossil fuels, exacerbating environmental concerns over its widespread use. In alignment with principles of environmental sustainability, the biotechnological upcycling of PET has recently emerged as a compelling solution. Since the discovery of PETase, a hydrolase capable of depolymerizing this polyester, enzymatic plastic breakdown is increasingly considered as a promising solution for managing PET waste. This enzyme and its improved derivatives, such as Fast‐PETase, enable the breakdown of PET into bis(2‐41 hydroxyethyl) terephthalate (BHET) and mono(2‐hydroxyethyl) terephthalate (MHET). Subsequently, the enzyme MHETase is responsible for further degradation of MHET into ethylene glycol and terephthalic acid. The metabolic capability of microorganisms to utilize these monomers of PET for growth has been explored in various biotechnological applications, especially in the context of bioremediation and bioconversion processes aimed at transforming plastic waste into useful products using genetically engineered bacteria.
Project description:Plants from the Nepenthes genus, which enumerates approximately 120 species, possess specialized pitchers enabling them to capture and digest various preys, mainly arthropods, from which the plants derive nutrients. The pitcher fluid contains many molecules of noteworthy importance, including antimicrobial compounds, traditionally used in medicine, as well as hydrolytic enzymes for prey digestion. In this study, polyesters films made from poly(ethylene terephthalate) (PET) and from poly(butylene adipate -co- terephthalate) (PBAT) were incubated in the pitcher of the carnivorous plants Nepenthes alata and Sarracenia purpurea. High performance liquid chromatography analysis revealed hydrolysis into their corresponding monomers, while hydrolysis efficiency was up to ten times higher in the presence of dried mealworm Tenebrio molitor and jasmonic acid. Proteomic analysis indicated the presence of the aspartic proteinase nepenthesin in most conditions, with high abundance in 70% of polyester-containing conditions compared to those without polyesters. Molecular docking simulations further suggested that nepenthesin has the potential to hydrolyze polyesters. While in contrast to cutinases there is only little information on hydrolysis of PET and PBAT by proteases in the literature, this work clearly demonstrates hydrolysis of both PET and PBAT by the recombinant protease nepenthesin, releasing similar amounts of TPA as the cutinase from Humicola insolens. These results suggest carnivorous plant fluids as a source for new enzymes for industrial applications such as for polyester hydrolysis.
Project description:Gifu Prefecture and Gifu University are developing technologies for recycling used carbon fiber because the waste disposal process is highly cost and energy intensive. However, generation of carbon fiber dust during the recycling process is a serious issue, especially in the occupational environment. Recycling requires carbonization by partial firing treatment at 500℃ followed by firing treatment at 440℃: these processes produce dust as a by-product. In this study, three types of carbon fibers; before recycling, after carbonization, and after firing were evaluated for their toxic effects on mice. It is important to study the influence of carbon fibers on human health at a gene expression level.
Project description:Gifu Prefecture and Gifu University are developing technologies for recycling used carbon fiber because the waste disposal process is highly cost and energy intensive. However, generation of carbon fiber dust during the recycling process is a serious issue, especially in the occupational environment. Recycling requires carbonization by partial firing treatment at 500℃ followed by firing treatment at 440℃: these processes produce dust as a by-product. In this study, three types of carbon fibers; before recycling, after carbonization, and after firing were evaluated for their toxic effects on mice. It is important to study the influence of carbon fibers on human health at a gene expression level.
Project description:Synthetic plastics, like polyethylene terephthalate (PET), have become an essential part of modern life. Many of these products are remarkably persistent in the environment, and the accumulation in the environment is recognised as a major threat. Therefore, an increasing interest has been paid to screen for organisms able to degrade and assimilate the plastic. Ideonella sakaiensis was isolated from a plastisphere, a bacterium that solely was thriving on the degradation on PET films. The processes affected by the presence of PET, terephthalic acid, ethylene glycol, ethyl glycolate, and sodium glyoxylate monohydrate was elucidated by differential proteomes. The exposure of PET and its monomers seem to affect two major pathways, the TCA cycle and the β-oxidation pathway, since multiple of the conditions resulted in an increased expression of proteins directly or indirectly involved in these pathways, underlying the importance in the degradation of PET by I. sakaiensis.
Project description:Synthetic plastics, like polyethylene terephthalate (PET), have become an essential part of modern life. Many of these products are remarkably persistent in the environment, and the accumulation in the environment is recognised as a major threat. Therefore, an increasing interest has been paid to screen for organisms able to degrade and assimilate the plastic. Ideonella sakaiensis was isolated from a plastisphere, a bacterium that solely was thriving on the degradation on PET films. The processes affected by the presence of PET, terephthalic acid, ethylene glycol, ethyl glycolate, and sodium glyoxylate monohydrate was elucidated by differential proteomes. The exposure of PET and its monomers seem to affect two major pathways, the TCA cycle and the β-oxidation pathway, since multiple of the conditions resulted in an increased expression of proteins directly or indirectly involved in these pathways, underlying the importance in the degradation of PET by I. sakaiensis.
Project description:Carbon nanotubes (CNTs) are newly developed nanomaterials with unique chemical and physical properties. Exposure to airborne CNTs in occupational settings or via consumer products is expected to increase significantly within the next decade due to the vigorous synthesis and applications of these materials in numerous consumer and industrial activities. Previous studies have shown that multiwalled CNT (MWCNT) induce pulmonary inflammation and pulmonary fibrosis. In the present study, we investigated genotoxic potential of MWCNTs. Female MutaMouse were exposed to 42.7 ug/mouse or 128 ug/mouse doses of MWCNTs Mitsui XNRi-7 or NM 401 once a week for four consecutive weeks. Doses were administered via intratracheal instillation. Lung tissues were collected 56 days post-exposure. Bronchoalveolar lavage(BAL) fluid cellularity, BAL and lung tissue DNA damage (COMET assay), lacz mutation frequency and global gene expression changes in lung tissue were determined.
Project description:As the application of carbon nanotubes (CNT) in consumer products continues to rise, studies have expanded to determine the associated risks of exposure on human and environmental health. In particular, several lines of evidence indicate that exposure to multi-walled carbon nanotubes (MWCNT) could pose a carcinogenic risk similar to asbestos fibers. However, to date the potential markers of MWCNT exposure are not yet explored in humans.
Project description:Yeast strains lacking orthologs of mammalian eIF2D (Tma64), and either MCT-1 (Tma20) or DENR (Tma22) are broadly impaired for 40S recycling; however, it was unknown whether this defect leads to reduced 43S PIC levels with an impact on translation of particular mRNAs. To test this, we by combined ribosome footprint profiling with RNA-seq analysis of mRNA abundance.
Project description:The recycling of ribosomal subunits after translation termination is critical for efficient gene expression. Tma64 (eIF2D), Tma20 (MCT-1), and Tma22 (DENR) function as 40S recycling factors in vitro, but it is unknown whether they perform this function in vivo or serve as alternative initiation factors. Ribosome profiling of strains missing these factors revealed 80S ribosomes queued behind the stop codon, consistent with a block in 40S recycling. We found that unrecycled ribosomes could reinitiate translation at AUG codons in the 3’UTR, as evidenced by peaks in the footprint data and 3’UTR reporter analysis. In vitro translation experiments using reporter mRNAs containing upstream ORFs (uORFs) further established that reinitiation increased in the absence of these proteins. In some cases, 40S ribosomes appeared to rejoin with 60S subunits and undergo an alternative 80S reinitiation process in 3’UTRs. These results support a crucial role for Tma64, Tma20, and Tma22 in the recycling of 40S ribosomal subunits at stop codons and translation reinitiation.