Polyurethane foam induces epigenetic modification of mitochondrial DNA during different metamorphic stages of Tenebrio molitor

A Hydrogen-Bonded Organic Framework-Based Mitochondrion-Targeting Bioorthogonal Platform for the Modulation of Mitochondrial Epigenetics

Bioorthogonal chemistry represents a powerful tool in chemical biology, which shows great potential in epigenetic modulation. As a proof of concept, the epigenetic modulation model of mitochondrial DNA (mtDNA) is selected because mtDNA establishes a relative hypermethylation stage under oxidative stress, which impairs the mitochondrion-based therapeutic effect during cancer therapy. Herein, we design a new biocompatible hydrogen-bonded organic framework (HOF) for a HOF-based mitochondrion-targeting bioorthogonal platform TPP@P@PHOF-2. PHOF-2 can activate a prodrug (pro-procainamide) in situ, which can specifically inhibit DNA methyltransferase 1 (DNMT1) activity and remodel the epigenetic modification of mtDNA, making it more susceptible to ROS damage. In addition, PHOF-2 can also catalyze artemisinin to produce large amounts of ROS, effectively damaging mtDNA and achieving better chemodynamic therapy demonstrated by both in vitro and in vivo studies. This work provides new insights into developing advanced bioorthogonal therapy and expands the applications of HOF and bioorthogonal catalysis.

Biodegradation of polyether-polyurethane foam in yellow mealworms (Tenebrio molitor) and effects on the gut microbiome

Polyurethane (PU) is one of the mass-produced recalcitrant plastics with a high environmental resistance but extremely low biodegradability. Therefore, improperly disposed PU waste adds significantly to plastic pollution, which must be addressed immediately. In recent years, there has been an increasing number of reports on plastic biodegradation in insect larvae, especially those that can feed on polyethylene and polystyrene. This study revealed that yellow mealworm (Tenebrio molitor) larvae can chew and ingest polyether-PU foams efficiently, resulting in a significant mass loss of nearly 67% after 35 days at a similar survival rate compared to when fed on bran. However, polyether-PU fragments were found in the frass of T. molitor, indicating that polyether-PU biodegradation and bioconversion in intestinal tracts were not complete. The scission of ether and urethane bonds in the polyether-PU can be evidenced by comparing polymer fragments recovered from frass with the pristine ones using Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Gel permeation chromatography suggested the release of low-molecular-weight oligomers as a result of the biodegradation, which also resulted in poor thermal stability of the polyether-PU foam as determined by thermogravimetric analysis. High-throughput sequencing of the gut microbiome revealed significant changes in the microbial community populations due to the polyether-PU diet, for example, an increase in the families Enterobacteriaceae and Streptococcaceae, suggesting that these microorganisms may contribute to the polyether-PU biodegradation.

Biodegradation of Different Types of Plastics by Tenebrio molitor Insect

Looking for new, sustainable ways to utilize plastics is still a very pertinent topic considering the amount of plastics produced in the world. One of the newest and intriguing possibility is the use of insects in biodegradation of plastics, which can be named entomoremediation. The aim of this work was to demonstrate the ability of the insect Tenebrio molitor to biodegrade different, real plastic waste. The types of plastic waste used were: remains of thermal building insulation polystyrene foam (PS), two types of polyurethane (kitchen sponge as PU1 and commercial thermal insulation foam as PU2), and polyethylene foam (PE), which has been used as packaging material. After 58 days, the efficiency of mass reduction for all of the investigated plastics was 46.5%, 41.0%, 53.2%, and 69.7% for PS, PU1, PU2, and PE, respectively (with a dose of 0.0052 g of each plastic per 1 mealworm larvae). Both larvae and imago were active plastic eaters. However, in order to shorten the duration of the experiment and increase the specific consumption rate, the two forms of the insect should not be combined together in one container.

Effects of power frequency electric field exposure on kidney

With the rapid development of ultra high voltage alternating current (UHV AC) transmission, the intensity of environmental power frequency electric field (PFEF) near UHV AC transmission lines increased continuously, which has attracted considerable public attention on the potential health effects of PFEF. In this study, the effect of PFEF exposure on the kidney was explored. Institute of Cancer Research (ICR) mice were exposed to 35 kV/m PFEF (50 Hz). Two indicators relating to renal function (urea nitrogen and creatinine) were tested after the exposure of 7d, 14d, 21d, 35d and 49d. The pathological morphology and cellular ultrastructure of kidney were observed respectively by light microscopy and electron microscopy after the exposure of 25d and 52d. Results showed that compared with that of the control group, the concentration of urea nitrogen of 35 kV/m PFEF exposure group significantly increased on the 21st and 35th days, and the concentration of creatinine significantly increased on the 14th, 21st and 35th days. However, the concentrations of creatinine and urea nitrogen both returned to normal levels on the 49th day. Furthermore, an enlarged Bowman's space, the vacuolation of renal tubular epithelial cells and the foot process effacement of podocyte were found after 25d exposure, but no abnormality was observed after 52d exposure. Obviously, a short-term (35d) exposure of 35 kV/m PFEF could cause kidney injury, which could be recovered after a longer-term (52d) exposure. Based on this study and relevant literatures, one explanation for this two-way effect is as follows. Kidney injury was caused by the disequilibrium of mitochondrial dynamics under 35 kV/m PFEF exposure. PFEF could also activate Wnt/β-catenin signal to promote the recovery of renal tubular epithelial cells and glomerular podocytes, so kidney injury could be repaired.