Catalytic and biocatalytic degradation of microplastics.

In recent years, there has been a surge in annual plastic production, which has contributed to growing environmental challenges, particularly in the form of microplastics. Effective management of plastic and microplastic waste has become a critical concern, necessitating innovative strategies to address its impact on ecosystems and human health. In this context, catalytic degradation of microplastics emerges as a pivotal approach that holds significant promise for mitigating the persistent effects of plastic pollution. In this article, we critically explored the current state of catalytic degradation of microplastics and discussed the definition of degradation, characterization methods for degradation products, and the criteria for standard sample preparation. Moreover, the significance and effectiveness of various catalytic entities, including enzymes, transition metal ions (for the Fenton reaction), nanozymes, and microorganisms are summarized. Finally, a few key issues and future perspectives regarding the catalytic degradation of microplastics are proposed.

Kirigami triboelectric spider fibroin microneedle patches for comprehensive joint management.

Joint injuries are among the leading causes of disability. Present concentrations were focused on oral drugs and surgical treatment, which brings severe and unnecessary difficulties for patients. Smart patches with high flexibility and intelligent drug control-release capacity are greatly desirable for efficient joint management. Herein, we present a novel kirigami spider fibroin-based microneedle triboelectric nanogenerator (KSM-TENG) patch with distinctive features for comprehensive joint management. The microneedle patch consists of two parts: the superfine tips and the flexible backing base, which endow it with great mechanical strength to penetrate the skin and enough flexibility to fit different bends. Besides, the spider fibroin-based MNs served as a positive triboelectric material to generate electrical stimulation, thereby forcing drug release from needles within 720 min. Especially, kirigami structures could also transform the flat patch into three dimensions, which could impart the patch with flexible properties to accommodate the complicated processes produced by joint motion. Benefiting from these traits, the KSM-TENG patch presents excellent performance in inhibiting the inflammatory response and promoting wound healing in mice models. The results indicated that the mice possessed only 2% wound area and the paw thickness was reduced from 10.5 mm to 6.2 mm after treatment with the KSM-TENG patch, which further demonstrates the therapeutic effect of joints in vivo. Thus, it is believed that the proposed novel KSM-TENG patch is valuable in the field of comprehensive treatments and personalized clinical applications.

The lactate to albumin ratio linked to all-cause mortality in critically ill patients with septic myocardial injury.

Background: The lactate to albumin ratio (LAR) has emerged as a promising prognostic marker in critically ill patients. Despite its potential utility, the prognostic value of LAR in septic myocardial injury (SMI) remains uncertain. Methods: This study aims to investigate the prognostic significance of LAR in SMI through a retrospective cohort analysis of data from the Medical Information Mart for Intensive Care III (MIMIC-III) (v1.4) database. The study included intensive care unit (ICU)-admitted patients (age ≥18 years) diagnosed with SMI. The primary endpoint was in-hospital mortality. Results: A total of 704 patients were included in the study, of which 59.10% were male. Hospital mortality and ICU mortality rates were recorded at 29.97% and 22.87%, respectively. After adjusting for confounding factors, multivariate Cox proportional risk analysis demonstrated that LAR was independently associated with an increased risk of both hospital mortality (HR, 1.39 [95% CI: 1.24-1.56] P < 0.001) and ICU mortality (HR, 1.46 [95% CI: 1.29-1.65] P < 0.001). Furthermore, the generalized additive model (GAM) and restricted cubic spline (RCS) model indicated a linear relationship between LAR and mortality rates in the ICU and hospital. Conclusions: The LAR may serve as a potential prognostic biomarker in critically ill patients with SMI. High LAR levels are associated with a higher risk of in-hospital mortality and can help identify individuals with high mortality rates. Overall, the findings emphasize the importance of using LAR as a tool for risk stratification and management of critically ill patients with SMI.

Role of RIPK3­CaMKII­mPTP signaling pathway­mediated necroptosis in cardiovascular diseases (Review).

Necroptosis, which is distinct from apoptosis and necrosis, serves a crucial role in ontogeny and the maintenance of homeostasis. In the last decade, it has been demonstrated that the pathogenesis of cardiovascular diseases is also linked to necroptosis. Receptor interaction protein kinase (RIPK) 1, RIPK3 and mixed lineage kinase domain­like protein serve vital roles in necroptosis. In addition to the aforementioned necroptosis­related components, calcium/calmodulin­dependent protein kinase II (CaMKII) has been identified as a novel substrate for RIPK3 that promotes the opening of the mitochondrial permeability transition pore (mPTP), and thus, mediates necroptosis of myocardial cells through the RIPK3­CaMKII­mPTP signaling pathway. The present review provides an overview of the current knowledge of the RIPK3­CaMKII­mPTP­mediated necroptosis signaling pathway in cardiovascular diseases, focusing on the role of the RIPK3­CaMKII­mPTP signaling pathway in acute myocardial infarction, ischemia­reperfusion injury, heart failure, abdominal aortic aneurysm, atherosclerosis, diabetic cardiomyopathy, hypertrophic cardiomyopathy, atrial fibrillation, and the cardiotoxicity associated with antitumor drugs and other chemicals. Finally, the present review discusses the research status of drugs targeting the RIPK3­CaMKII­mPTP signaling pathway.

Engineering of Porous Silica Coated Gold Nanorods by Surface-Protected Etching and Their Applications in Drug Loading and Combined Cancer Therapy.

Core-shell nanostructures, specifically gold nanorods coated with porous silica (GNR@p-SiO2), were successfully fabricated by surface-protected etching. The nanostructures, photothermal effects, drug loading and drug release behaviors, cellular uptake, and combined chemo-photothermal therapy were investigated. The results showed that the as-prepared GNR@p-SiO2 had a uniform porous silica outer layer. Etching process could be modulated by adjusting the etching time, concentrations of etching agents, and concentrations of protective agents. With doxorubicin (DOX) as the model drug, the drug loading capacity reached 18.9%, which was dependent on the DOX concentrations. The drug release profiles were dual stimulus-responsive to pH and laser irradiation. In addition, the GNR@p-SiO2 nanoparticles were biocompatible and effectively internalized by cancer cells. Compared with chemotherapy or photothermal therapy administered individually, combined chemo-photothermal therapy using GNR@p-SiO2 exhibited higher efficiency in killing cancer cells both in vitro and in vivo. Therefore, surface-protected etching is a powerful method for preparing core-shell nanostructures capped with mesoporous silica for combined cancer chemo-photothermal therapy.

Elucidation of the Molecular Determinants for Optimal Perfluorooctanesulfonate Adsorption Using a Combinatorial Nanoparticle Library Approach.

Perfluorooctanesulfonate (PFOS) persistently accumulates in the environment and in humans, causing various toxicities. To determine the key molecular determinants for optimal PFOS specificity and efficiency, we designed and synthesized a combinatorial gold nanoparticle (GNP) library consisting of 18 members with rationally diversified hydrophobic, electrostatic, and fluorine-fluorine interaction components for PFOS bindings. According to our findings, the electrostatic and F-F interactions between PFOS and nanoparticles are complementary. When F-F attractions are relatively weak, the electrostatic interactions are dominant. As F-F interactions increase, the electrostatic contributions are reduced to as low as 20%, demonstrating that F-F binding may overpower even electrostatic interactions. Furthermore, F-F interactions (28-79% binding efficiency) are 2-fold stronger than regular hydrophobic interactions (15-39% binding efficiency) for PFOS adsorption, explaining why these novel PFOS-binding nanoparticles are superior to other conventional materials based on either hydrophobic or electrostatic binding. The PFOS adsorption by the optimized nanoparticles performs well in the presence of ionic interferences and in environmental wastewater. This library mapping approach can potentially be applied to recognition mechanism investigation of other pollutants and facilitate the discovery of effective monitoring probes and matrices for their removal.

The effects of Pantoea sp. strain Y4-4 on alfalfa in the remediation of heavy-metal-contaminated soil, and auxiliary impacts of plant residues on the remediation of saline-alkali soils.

The plant-growth-promoting rhizobacterium (PGPR) Y4-4 was isolated from plant rhizosphere soil and identified as Pantoea sp. by 16S rRNA sequence analysis. The effects of strain Y4-4 on alfalfa grown in heavy-metals-contaminated soil was investigated using a pot experiment. In a Cu-rich environment, the shoot dry mass and total dry mass of plants inoculated with strain Y4-4 increased by 22.6% and 21%, and Cu accumulation increased by 15%. In a Pb-Zn-rich environment, the shoot dry mass and total dry mass of plants inoculated with strain Y4-4 increased by 23.4% and 22%, and Zn accumulation increased by 30.3%. In addition, the salt tolerance and biomass of wheat seedlings could be improved by applying strain Y4-4 mixed with plant residue as a result of the Cu-rich plant residues providing copper nutrition to wheat. This study offers an efficient PGPR with strong salt tolerance and a safe strategy for the post-treatment of plant residue.

Cloning, heterologous expression, and enzymatic characterization of a novel glucoamylase GlucaM from Corallococcus sp. strain EGB.

The gene encoding a novel glucoamylase (GlucaM) from the Corallococcus sp. strain EGB was cloned and heterologous expressed in Escherichia coli BL21(DE3), and the enzymatic characterization of recombinant GlucaM (rGlucaM) was determined in the study. The glucaM had an open reading frame of 1938 bp encoding GlucaM of 645 amino acids with no signal peptide. GlucaM belongs to glycosyl hydrolase family 15 and shares the highest identity 96% with the GH15 glucoamylase of Corallococcus coralloides DSM 2259. The rGlucaM with His-tag was purified by the Ni2+-NTA resin, with a specific activity from 3.4 U/mg up to 180 U/mg, and the molecular weight of rGlucaM was approximately 73 kDa on SDS-PAGE. The Km and Vmax of rGlucaM for soluble starch were 1.2 mg/mL and 46 U/mg, respectively. rGlucaM was optimally active at pH 7.0 and 50 °C and had highly tolerance to high concentrations of salts, detergents, and various organic solvents. rGlucaM hydrolyzed soluble starch to glucose, and hydrolytic activities were also detected with amylopectin, amylase, glycogen, starch (potato), α-cyclodextrin, starch (corn and potato). The analysis of hydrolysis products shown that rGlucaM with α-(1-4),(1-6)-D-glucan glucohydrolase toward substrates. These characteristics indicated that the GlucaM was a new member of glucoamylase family and a potential candidate for industrial application.

Metabolic pathway involved in 2-methyl-6-ethylaniline degradation by Sphingobium sp. strain MEA3-1 and cloning of the novel flavin-dependent monooxygenase system meaBA.

2-Methyl-6-ethylaniline (MEA) is the main microbial degradation intermediate of the chloroacetanilide herbicides acetochlor and metolachlor. Sphingobium sp. strain MEA3-1 can utilize MEA and various alkyl-substituted aniline and phenol compounds as sole carbon and energy sources for growth. We isolated the mutant strain MEA3-1Mut, which converts MEA only to 2-methyl-6-ethyl-hydroquinone (MEHQ) and 2-methyl-6-ethyl-benzoquinone (MEBQ). MEA may be oxidized by the P450 monooxygenase system to 4-hydroxy-2-methyl-6-ethylaniline (4-OH-MEA), which can be hydrolytically spontaneously deaminated to MEBQ or MEHQ. The MEA microbial metabolic pathway was reconstituted based on the substrate spectra and identification of the intermediate metabolites in both the wild-type and mutant strains. Plasmidome sequencing indicated that both strains harbored 7 plasmids with sizes ranging from 6,108 bp to 287,745 bp. Among the 7 plasmids, 6 were identical, and pMEA02' in strain MEA3-1Mut lost a 37,000-bp fragment compared to pMEA02 in strain MEA3-1. Two-dimensional electrophoresis (2-DE) and protein mass fingerprinting (PMF) showed that MEA3-1Mut lost the two-component flavin-dependent monooxygenase (TC-FDM) MeaBA, which was encoded by a gene in the lost fragment of pMEA02. MeaA shared 22% to 25% amino acid sequence identity with oxygenase components of some TC-FDMs, whereas MeaB showed no sequence identity with the reductase components of those TC-FDMs. Complementation with meaBA in MEA3-1Mut and heterologous expression in Pseudomonas putida strain KT2440 resulted in the production of an active MEHQ monooxygenase.

Differences in Copper Absorption and Accumulation between Copper-Exclusion and Copper-Enrichment Plants: A Comparison of Structure and Physiological Responses.

Differences in copper (Cu) absorption and transport, physiological responses and structural characteristics between two types of Cu-resistant plants, Oenothera glazioviana (Cu-exclusion type) and Elsholtzia haichowensis (Cu-enrichment type), were investigated in the present study. The results indicated the following: (1) After 50 µM Cu treatment, the Cu ratio in the xylem vessels of E. haichowensis increased by 60%. A Cu adsorption experiment indicated that O. glazioviana exhibited greater resistance to Cu, and Cu absorption and the shoot/root ratio of Cu were significantly lower in O. glazioviana than in E. haichowensis. (2) An analysis of the endogenous abscisic acid (ABA) variance and exogenous ABA treatment demonstrated that the ABA levels of both plants did not differ; exogenous ABA treatment clearly reduced Cu accumulation in both plants. (3) The leaf stomatal density of O. glazioviana was significantly less than that of E. haichowensis. Guard cells in E. haichowensis plants were covered with a thick cuticle layer, the epidermal hair was more numerous and longer, and the number of xylem conduits in the root was small. (4) The transpiration rate and the stomatal conductance of O. glazioviana were both significantly lower than those of E. haichowensis, regardless of whether the plants were treated with Cu. Taken together, these results indicate that the differences in the structural characteristics between these two plant species, particularly in the characteristics related to plant transpiration, are important factors that govern whether plants acquire or exclude Cu.

Purification and Characterization of a Novel Extracellular Thermostable Alkaline Protease from Streptomyces sp. M30.

A novel alkaline protease from Streptomyces sp. M30, SapHM, was purified by ammonium sulfate precipitation, hydrophobic interaction chromatography, and DEAE-Sepharose chromatography, with a yield of 15.5% and a specific activity of 29,070 U/mg. Tryptic fragments of the purified SapHM were obtained by electrospray ionization quadrupole time-of- flight mass spectrometry. Nucleotide sequence analysis revealed that the gene sapHM contained 1,179 bp, corresponding to 392 amino acids with conserved Asp156, His187, and Ser339 residues of alkaline protease. The first 24 amino acid residues were predicted to be a signal peptide, and the molecular mass of the mature peptide was 37.1 kDa based on amino acid sequences and mass spectrometry. Pure SapHM was optimally active at 80°C in 50 mM glycine-NaOH buffer (pH 9.0), and was broadly stable at 0-50 °C and pH 4.0-9.0. The protease relative activity was increased in the presence of Ni(2+), Mn(2+), and Cu(2+) to 112%, 113%, and 147% of control, respectively. Pure SapHM was also activated by dimethylformamide, dimethyl sulfoxide, Tween 80, and urea. The activity of the purified enzyme was completely inhibited by phenylmethylsulfonyl fluoride, indicating that it is a serine-type protease. The Km and Vmax values were estimated to be 35.7 mg/ml, and 5 × 10(4) U/mg for casein. Substrate specificity analysis showed that SapH was active on casein, bovine serum albumin, and bovine serum fibrin.

Biodegradation of fenoxaprop-P-ethyl (FE) by Acinetobacter sp. strain DL-2 and cloning of FE hydrolase gene afeH.

Fenoxaprop-P-ethyl (FE) is widely used as a post-emergence aryloxyphenoxy propionate (AOPP) herbicide in agriculture. An efficient FE-degrading strain DL-2 was isolated from the enrichment culture and identified as Acinetobacter sp. and the metabolite fenoxaprop acid (FA) was identified by HPLC/MS analysis. The strain DL-2 could also degrade a wide range of other AOPP herbicides. A novel FE hydrolase esterase gene afeH was cloned from strain DL-2 and functionally expressed in Escherichia coli BL21(DE3). The specific activities of recombinant AfeH was 216.39 U mg(-1) for FE with Km and Vmax values of 0.82 µM and 7.94 µmol min(-1) mg(-1). AfeH could also hydrolyze various AOPP herbicides, p-nitrophenyl esters and triglycerides. The optimal pH and temperature for recombinant AfeH were 9.0 and 50°C, respectively; the enzyme was activated by Co(2+) and inhibited by Ca(2+), Zn(2+), Ba(2+). AfeH was inhibited strongly by phenylmethylsulfonyl and SDS and weakly by dimethyl sulfoxide.

Experimental modulation and computational model of nano-hydrophobicity.

We demonstrate that nano-hydrophobicity, which governs the biological aggressiveness of nanoparticles, is determined by the outermost regions of surface ligands. We have also successfully modulated nano-hydrophobicity using systematic surface ligand modifications and built the first computational model of nano-hydrophobicity.

Purification, cloning, expression, and biochemical characterization of a monofunctional catalase, KatP, from Pigmentiphaga sp. DL-8.

Catalases are essential components of the cellular equipment used to cope with oxidative stress. The monofunctional catalase KatP was purified from Pigmentiphaga sp. using ammonium sulfate precipitation (ASP), diethylaminoethyl ion exchange chromatography (IEC), and hydrophobic interaction chromatography (HIC). The purified catalase formed polymer with an estimated monomer molecular mass of 54kDa, which were resolved by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and zymogram analysis. KatP exhibited a specific catalytic activity of 73,000U/mg, which was higher than that of catalase-1 of Comamonas terrigena N3H (55,900U/mg). Seven short tryptic fragments of this catalase were obtained by electrospray ionization quadrupole time-of-flight mass spectrometry (ESI-Q-TOF MS/MS), and the gene, katP, was cloned by PCR amplification and overexpressed in Escherichia coli BL21 (DE3). Based on the complete amino acid sequence, KatP was identified as a clade 3 monofunctional catalase. The specific activities of recombinant KatP for hydrogen peroxide (690,000U/mg) increased 9-fold over that of the parent strain. The Km and Vmax of recombinant KatP were 9.48mM and 81.2mol/minmg, respectively. The optimal pH and temperature for KatP were 7.0 and 37°C, respectively, and the enzyme displayed abroad pH-stable range of 4.0-11.0. The enzyme was inhibited by Zn(2+), Cu(2+), Cr(2+), and Mn(2+), whereas Fe(3+) and Mg(2+) stimulated KatP enzymatic activity. Interestingly, the catalase activity of recombinant KatP displayed high stability under different temperature and pH conditions, suggesting that KatP is a potential candidate for the production of catalase.