Biodegradation of Typical Plastics: From Microbial Diversity to Metabolic Mechanisms.

Plastic production has increased dramatically, leading to accumulated plastic waste in the ocean. Marine plastics can be broken down into microplastics (<5 mm) by sunlight, machinery, and pressure. The accumulation of microplastics in organisms and the release of plastic additives can adversely affect the health of marine organisms. Biodegradation is one way to address plastic pollution in an environmentally friendly manner. Marine microorganisms can be more adapted to fluctuating environmental conditions such as salinity, temperature, pH, and pressure compared with terrestrial microorganisms, providing new opportunities to address plastic pollution. Pseudomonadota (Proteobacteria), Bacteroidota (Bacteroidetes), Bacillota (Firmicutes), and Cyanobacteria were frequently found on plastic biofilms and may degrade plastics. Currently, diverse plastic-degrading bacteria are being isolated from marine environments such as offshore and deep oceanic waters, especially Pseudomonas spp. Bacillus spp. Alcanivoras spp. and Actinomycetes. Some marine fungi and algae have also been revealed as plastic degraders. In this review, we focused on the advances in plastic biodegradation by marine microorganisms and their enzymes (esterase, cutinase, laccase, etc.) involved in the process of biodegradation of polyethylene terephthalate (PET), polystyrene (PS), polyethylene (PE), polyvinyl chloride (PVC), and polypropylene (PP) and highlighted the need to study plastic biodegradation in the deep sea.

Biodegradation of polyethylene terephthalate (PET) by diverse marine bacteria in deep-sea sediments.

PET plastic waste entering the oceans is supposed to take hundreds of years to degrade and tends to accumulate in the deep sea. However, we know little about the bacteria capable of plastic degradation therein. To determine whether PET-degrading bacteria are present in deep-sea sediment, we collected the samples from the eastern central Pacific Ocean and initiated microbial incubation with PET as the carbon source. After enrichment with PET for 2 years, we gained all 15 deep-sea sediment communities at five oceanic sampling sites. Bacterial isolation for pure culture and further growth tests confirmed that diverse bacteria possess degradation ability including Alcanivorax xenomutans BC02_1_A5, Marinobacter sediminum BC31_3_A1, Marinobacter gudaonensis BC06_2_A6, Thalassospira xiamenensis BC02_2_A1 and Nocardioides marinus BC14_2_R3. Furthermore, four strains were chosen as representatives to reconfirm the PET degradation capability by SEM, weight loss and UPLC-MS. The results showed that after 30-day incubation, 1.3%-1.8% of PET was lost. De-polymerization of PET by the four strains was confirmed by the occurrence of the PET monomer of MHET and TPA as the key degradation products. Bacterial consortia possessing PET-degrading potential are prevalent and diverse and might play a key role in the removal of PET pollutants in deep oceans.

Forel-Ule index extraction and spatiotemporal variation from MODIS imagery in the Bohai Sea of China.

In large-scale water quality evaluation, traditional field-measured data lack spatial-temporal representativeness, and the role of conventional remote sensing parameters (SST, Chla, TSM, etc.) is controversial. By calculating and grading the hue angle of a water body, a Forel-Ule index (FUI) can be obtained, which provides a comprehensive statement of water condition. Using MODIS imagery, hue angles are extracted with better accuracy than the literature's method. It is found that FUI changes in the Bohai Sea have correlated consistently with water quality. The decreasing trend of non-excellent water quality areas in the Bohai Sea was highly correlated with FUI (R2 = 0.701) during the government-dominated land-based pollution reduction program (2012-2021). FUI can monitor and evaluate seawater quality.

Muricauda aurea sp. nov. and Muricauda profundi sp. nov., two marine bacteria isolated from deep sea sediment of Pacific Ocean.

Two novel Gram-stain-negative, aerobic, rod-shaped, carotenoid-pigmented and non-flagellated bacteria, designated BC31-1-A7T and BC31-3-A3T, were isolated from polyethylene-terephthalate-degrading bacterial consortia enriched from deep-sea sediment collected in the Pacific Ocean. Optimal growth of both strains was observed at 28-32 °C, at pH 7.5 and in the presence of 3-4% (w/v) NaCl. The 16S rRNA gene sequence analysis revealed that strains BC31-1-A7T and BC31-3-A3T were closely related to Muricauda aquimarina JCM 11811T, Muricauda lutimaris KCTC 22173T, Muricauda ruestringensis DSM 13258T, Muricauda zhangzhouensis DSM 25030T, Muricauda oceani JCM 33902T and Muricauda oceanensis KCTC 72200T with 96.8-98.9% sequence similarity. The 16S rRNA gene sequence similarity between strains BC31-1-A7T and BC31-3-A3T was 97.5%. The genomic G+C contents of strains BC31-1-A7T and BC31-3-A3T were 42.1 and 41.6 mol%, respectively. The average nucleotide identity and digital DNA-DNA hybridization values between strain BC31-3-A3T, strain BC31-1-A7T and their six closely related type strains were 77.6-84.3% and 20.5-27.9%, respectively. Menaquinone-6 was detected as the major isoprenoid quinone in all strains. Their major fatty acids were iso-C15:0, iso-C15:1 G and iso-C17:0 3-OH. The major polar lipids of strains BC31-1-A7T and BC31-3-A3T were identified as one phosphatidylethanolamine, some unidentified polar lipids and one aminolipid. Based on their distinct taxonomic characteristics, strains BC31-1-A7T and BC31-3-A3T represent two novel species in the genus Muricauda. The names proposed to accommodate these two strains are Muricauda aurea sp. nov. and Muricauda profundi sp. nov., and the type strains are BC31-1-A7T (=MCCC M23246T=KCTC 82569T) and BC31-3-A3T (=MCCC M23216T=KCTC 82302T), respectively.

One-Pot Green Process to Synthesize MXene with Controllable Surface Terminations using Molten Salts.

Surface terminations of two-dimensional MXene (Ti3 C2 Tx ) considerably impact its physicochemical properties. Commonly used etching methods usually introduce -F surface terminations or metallic impurities in MXene. We present a new molten-salt-assisted electrochemical etching method to synthesize fluorine-free Ti3 C2 Cl2 . Using electrons as reaction agents, cathode reduction and anode etching can be spatially isolated; thus, no metallics are present in the Ti3 C2 Cl2 product. The surface terminations can be in situ modified from -Cl to -O and/or -S, which considerably shortens the modification steps and enriches the variety of surface terminations. The obtained -O-terminated Ti3 C2 Tx are excellent electrode materials for supercapacitors, exhibiting capacitances of 225 F g-1 at 1.0 Ag-1 , good rate performance (91.1 % at 10 Ag-1 ), and excellent capacitance retention (100 % after 10000 charge/discharge cycles at 10 Ag-1 ), which is superior to multi-layered Ti3 C2 Tx prepared by other etching methods.

Evolution and synthesis of novel orally bioavailable inhibitors of PDE10A.

The design and synthesis of highly potent, selective orally bioavailable inhibitors of PDE10A is reported. Starting with an active compound of modest potency from a small focused screen, we were able to evolve this series to a lead molecule with high potency and selectivity versus other PDEs using structure-based design. A systematic refinement of ADME properties during lead optimization led to a lead compound with good half-life that was brain penetrant. Compound 39 was highly potent versus PDE10A (IC50=1.0 nM), demonstrated high selectivity (>1000-fold) against other PDEs and was efficacious when dosed orally in a rat model of psychosis, PCP-induced hyperlocomotion with an EC50 of 1 mg/kg.

Influence of the synergistic effect between Co-N-C and ceria on the catalytic performance for selective oxidation of ethylbenzene.

A series of catalysts, i.e. metal oxides (MO) such as CeO2, Fe2O3 and Al2O3 supported Co-N-C (Co-N-C/MO) were prepared by heating supported cobalt porphyrin in a N2 atmosphere. Among the Co-N-C/MO catalysts, Co-N-C/CeO2 shows a remarkable catalytic performance for ethylbenzene oxidation with ethylbenzene conversion of 33.1% and selectivity to acetophenone of 74.8%. In addition, the interaction between Co-N-C and supports was tentatively characterized by techniques such as XRD, HRTEM, XPS etc. According to XPS, the presence of the redox cycle between Ce(3+) and Ce(4+) in CeO2 facilitates the formation of cobalt ions in the high valence state and the Co-Nx sites, which are typically responsible for the high catalytic activity. The high performance benefits from the synergistic effect between Co-N-C and CeO2 and the well-dispersed Co-based sites.

Polyethylene terephthalate (PET)-degrading bacteria in the pelagic deep-sea sediments of the Pacific Ocean.

Polyethylene terephthalate (PET) plastic pollution is widely found in deep-sea sediments. Despite being an international environmental issue, it remains unclear whether PET can be degraded through bioremediation in the deep sea. Pelagic sediments obtained from 19 sites across a wide geographic range in the Pacific Ocean were used to screen for bacteria with PET degrading potential. Bacterial consortia that could grow on PET as the sole carbon and energy source were found in 10 of the 19 sites. These bacterial consortia showed PET removal rate of 1.8%-16.2% within two months, which was further confirmed by the decrease of carbonyl and aliphatic hydrocarbon groups using attenuated total reflectance-Fourier-transform infrared analysis (ATR-FTIR). Analysis of microbial diversity revealed that Alcanivorax and Pseudomonas were predominant in all 10 PET degrading consortia. Meanwhile, Thalassospira, Nitratireductor, Nocardioides, Muricauda, and Owenweeksia were also found to possess PET degradation potential. Metabolomic analysis showed that Alcanivorax sp. A02-7 and Pseudomonas sp. A09-2 could turn PET into mono-(2-hydroxyethyl) terephthalate (MHET) even in situ stimulation (40 MPa, 10 °C) conditions. These findings widen the currently knowledge of deep-sea PET biodegrading process with bacteria isolates and degrading mechanisms, and indicating that the marine environment is a source of biotechnologically promising bacterial isolates and enzymes.

Continuous generation and release of microplastics and nanoplastics from polystyrene by plastic-degrading marine bacteria.

Plastic waste released into the environments breaks down into microplastics due to weathering, ultraviolet (UV) radiation, mechanical abrasion, and animal grazing. However, little is known about the plastic fragmentation mediated by microbial degradation. Marine plastic-degrading bacteria may have a double-edged effect in removing plastics. In this study, two ubiquitous marine bacteria, Alcanivorax xenomutans and Halomonas titanicae, were confirmed to degrade polystyrene (PS) and lead to microplastic and nanoplastic generation. Biodegradation occurred during bacterial growth with PS as the sole energy source, and the formation of carboxyl and carboxylic acid groups, decreased heat resistance, generation of PS metabolic intermediates in cultures, and plastic weight loss were observed. The generation of microplastics was dynamic alongside PS biodegradation. The size of the released microplastics gradually changed from microsized plastics on the first day (1344 nm and 1480 nm, respectively) to nanoplastics on the 30th day (614 nm and 496 nm, respectively) by the two tested strains. The peak release from PS films reached 6.29 × 106 particles/L and 7.64 × 106 particles/L from degradation by A. xenomutans (Day 10) and H. titanicae (Day 5), respectively. Quantification revealed that 1.3% and 1.9% of PS was retained in the form of micro- and nanoplastics, while 4.5% and 1.9% were mineralized by A. xenomutans and H. titanicae at the end of incubation, respectively. This highlights the negative effects of microbial degradation, which results in the continuous release of numerous microplastics, especially nanoplastics, as a notable secondary pollution into marine ecosystems. Their fates in the vast aquatic system and their impact on marine lives are noted for further study.

Biodegradation of polystyrene (PS) by marine bacteria in mangrove ecosystem.

Plastics pollution poses a new threat to marine ecosystems. Mangrove locating at estuary worldwide is probably the most heavily polluted area trapping various plastics transported from terrestrial and nearby marine aquaculture. Expanded polystyrene (EPS) is one of most common plastic debris therein and even in the plastic garbage. Here we showed the bacterial diversity of the polystyrene-degrading microbial community from EPS waste sites from a subtropical mangrove area. After enrichment with EPS, the degradation consortia were obtained. They shared a similar community structure dominated by bacteria of Sphingomonadaceae, Rhodanobacteraceae, Rhizobiaceae, Dermacoccaceae, Rhodocyclaceae, Hyphomicrobiaceae, and Methyloligellaceae. Diverse bacteria standing for the first member of the genera of Novosphingobium, Gordonia, Stappia, Mesobacillus, Alcanivorax, Flexivirga, Cytobacillus, Thioclava, and Thalassospira showed PS degradation capability as a pure culture. Further, PS biodegradation of Gordonia sp. and Novosphingobium sp. was quantified by weight loss, in addition to obvious morphological and structural changes of the PS films observed by SEM, ATR-FTIR, and contact angle analysis. The formation of new oxygen-containing functional groups implied the degradation pathway of oxidation. Although the degradation rates ranged from 2.7% to 7.7% after one month in lab and possibly lower in situ, their role in EPS removal is unneglectable.

Research on the Impact of Home Nursing Based on Intelligent Medical Internet of Things on the Quality of Life of Patients with Hemophilia.

The purpose of this paper is to study the feasibility and economic benefits of intelligent medical Internet of Things (IOT) systems for improving the quality of life of hemophilia patients, thereby reducing the risk of teratogenicity and disability for patients. This article selects 60 severe hemophilia patients who were followed up in our hospital from 2018 to 2019 as the research object. In the intelligent medical system, the Gaussian mixture model discretization algorithm is used to preprocess patient data collection. The observation group uses the intelligent medical system to implement home nursing for the patients, and the control group uses ordinary home nursing. This paper evaluates the quality of life of the two groups of patients 6 months after the intervention, including self-care ability, transfer function, and home nursing cognitive ability. The research results show that the home nursing based on smart medical IOT proposed in this paper is feasible and effective for improving the quality of life of patients. It can effectively improve the patient's self-care ability and joint functions and has important reference value for the development of intelligent medical IOT equipment.

Role of primary reaction initiated by 254 nm UV light in the degradation of p-nitrophenol attacked by hydroxyl radicals.

The degradation kinetics of p-nitrophenol (p-NP) exposed to 254/185 nm UV light were studied in two modes, i.e., 254 nm UV light intensity enhanced mode and normal mode. It was observed that the extra 254 nm UV light source accelerated the degradation process both in the presence and the absence of oxygen. Considering that hydroxyl radical (*OH) is the dominant factor that causes the degradation of p-NP, the enhanced degradation that occurred in the presence of the extra light source was attributed to the synergistic effect between *OH attack and the primary reactions initiated by 254 nm UV light. The synergistic effect has been confirmed by 266 nm laser flash photolysis (LFP) experiments. It is demonstrated that the phenoxy radical generated from the photoionization of p-NP is capable of reacting with *OH. On the basis of these results, it should be noted that UV light could cause more severe damage to p-NP attacked by *OH in aqueous solution.

Acidity-triggered charge-reversible multilayers for construction of adaptive surfaces with switchable bactericidal and bacteria-repelling functions.

The acidity of a microenvironment in infected sites was utilized as the trigger to manipulate the bacterial behavior on the surface. Multilayers composed of dopamine-anchored poly(acrylic acid) (PAA-dopa) and chitosan quaternary ammonium salt (Q-CS) were deposited onto a surface via the layer-by-layer (LBL) assembly technology. The multilayer was crosslinked through the reaction of catechol moieties. The surface charge of the multilayer reversibly shifted from positive to negative as the pH increased without influencing the chemical composition and wettability of the top layer. The precise manipulation of the surface charge, and therefore, the biological function was achieved by varying the acidity. The bactericidal efficiency increased 15 times for E. coli, while almost 90% dead S. aureus and 100% E. coli were released from the surface when the pH increased from 5.0 to 7.4. Therefore, the functional surface was regenerated, which is particularly essential during the long-term treatment of chronic wounds. This study presented a new adaptive material responding to microenvironment acidity of the infected sites for efficient and safe antibacterial therapies.

Theoretical studies on the selective mechanisms of GSK3ß and CDK2 by molecular dynamics simulations and free energy calculations.

Glycogen synthase kinase 3 (GSK3) is a serine/threonine protein kinase which is widely involved in cell signaling and controls a broad number of cellular functions. GSK3 contains α and ß isoforms, and GSK3ß has received more attention and becomes an attractive drug target for the treatment of several diseases. The binding pocket of cyclin-dependent kinase 2 (CDK2) shares high sequence identity to that of GSK3ß, and therefore, the design of highly selective inhibitors toward GSK3ß remains a big challenge. In this study, a computational strategy, which combines molecular docking, molecular dynamics simulations, free energy calculations, and umbrella sampling simulations, was employed to explore the binding mechanisms of two selective inhibitors to GSK3ß and CDK2. The simulation results highlighted the key residues critical for GSK3ß selectivity. It was observed that although GSK3ß and CDK2 share the conserved ATP-binding pockets, some different residues have significant contributions to protein selectivity. This study provides valuable information for understanding the GSK3ß-selective binding mechanisms and the rational design of selective GSK3ß inhibitors.

One-pot synthesis of mesoporous silica hollow spheres with Mn-N-C integrated into the framework for ethylbenzene oxidation.

Mesoporous silica spheres with Mn-N-C materials integrated into the framework are synthesized via the surfactant (CTAB) template-assisted one-pot approach. A manganese porphyrin is used as the precursor of the Mn-N-C structure. The as-prepared catalyst exhibits remarkable activity and stability in heterogeneous catalytic systems for ethylbenzene oxidation.

GABAB R/GSK-3ß/NF-κB signaling pathway regulates the proliferation of colorectal cancer cells.

Colorectal cancer is one of the leading causes of highly fatal cancer-related deaths in the whole world. Fast growth is critical characteristic of colorectal cancer, the underlying regulatory mechanism of colorectal cell fast proliferation remains largely unknown. Here, we reported that activation of metabotropic γ-Aminobutyric acid receptor (GABAB R) signaling significantly inhibited the colorectal cell HT29 proliferation by arresting the cell at G1 phase. Inhibition of GABAB R activated GSK-3ß by reducing the phosphorylation level of GSK-3ß. Activation of GSK-3ß blocked the function of GABAB R signaling on repressing cell proliferation. We further found that GABAB R activation inhibited NF-κB activity. The promotion of cell proliferation caused by downregulation of GABRB R could be blocked by inhibition of NF-κB activation. Overall, activation of GABAB R leaded to inhibition of GSK-3ß activation to repress the NF-κB function during colorectal cancer cell proliferation. This study revealed critical function of GABAB R/GSK-3ß/NF-κB signaling pathway on regulating proliferation of colorectal cancer cell, which might provide a potential therapeutic target for clinical colorectal cancer treatment.

[Efficacy and safety study of subcutaneous injection of bortezomib in the treatment of de novo patients with multiple myeloma].

OBJECTIVE: To explore the efficacy and safety of subcutaneous injection of bortezomib in the treatment of de novo multiple myeloma (MM) patients. METHODS: A total of 36 MM patients treated with bortezomib, adriamycin and dexamethasone (PAD) from January 2012 to April 2013 were analyzed. Among them, 18 received improved PAD (improved PAD group) with the subcutaneous injection of bortezomib, another 18 received conventional PAD (PAD group). The efficacy and safety of two groups were analyzed. RESULTS: Except 4 cases can not be assessed, 32 patients were evaluated. Of 32 cases, 19(59.4%) achieved complete remission (CR) or very good partial remission (VGPR) after induction therapy, which were 61.1% and 57.1% for PAD group and improved PAD group, respectively (P=1.000). No significant difference between the time to achieve maximum effectiveness in two groups was detected. In the PAD group, one patient (5.6%) died of serious lung infection and eight (44.4%) experienced grade 3 or higher adverse events, while only one (5.6%) discontinued treatment in improved PAD group due to similar toxicity. Compared to PAD group, grade 3 or worse adverse events was significantly reduced in improved PAD group, the most common symptoms were leucopenia (33.3% vs 61.1%, P=0.086), thrombocytopenia (50.0% vs 61.1%), anaemia (27.8% vs 16.7%), infection (16.7% vs 50.0%, P=0.075), diarrhea (5.6% vs 33.3%, P=0.088), peripheral neuropathy(0 vs 27.8%, P=0.045). CONCLUSION: The improved PAD regimen by changing bortezomib from intravenous administration to subcutaneous injection significantly reduced adverse events, improved the safety of clinical application of bortezomib without affecting curative effect, and had great progress.

Direct electrochemistry and electrocatalysis of hemoglobin on chitosan-room temperature ionic liquid-TiO(2)-graphene nanocomposite film modified electrode.

TiO(2)-graphene nanocomposite was prepared by hydrolysis of titanium isopropoxide in colloidal suspension of graphene oxide and in situ hydrothermal treatment. The direct electrochemistry and electrocatalysis of hemoglobin in room temperature ionic liquid 1-Butyl-3-methylimidazolium hexafluorophosphate, chitosan and TiO(2)-graphene nanocomposite modified glassy carbon electrode were investigated. The biosensor was examined by using UV-vis spectroscopy, scanning electron microscopy and electrochemical methods. The results indicated that hemoglobin remained its bioactivity on the modified electrode, showing a couple of well-defined and quasi-reversible redox peaks, corresponding to hemoglobin Fe(III)/Fe(II) couple. The kinetic parameters for the electrode reaction, such as the formal potential (E(o')), the electron transfer rate constant (k(s)), the apparent coverage (Γ), and Michaelis-Menten constant (K(m)) were evaluated. The biosensor showed good electrochemical responses to the reduction of H(2)O(2) in the ranges of 1-1170 µM. The detection limit was 0.3 µM (S/N=3). The properties of this composite film, together with the bioelectrochemical catalytic activity, could make them useful in the development of bioelectronic devices, and investigation of electrochemistry of other heme proteins at functional interface.

Study on the mechanism of photo-degradation of p-nitrophenol exposed to 254 nm UV light.

The degradation mechanism of p-nitrophenol (p-NP) exposed to 254 nm UV light was studied in the presence and the absence of oxygen respectively via both steady-state photolysis and time-resolved laser flash photolysis (LFP) experiments. It has been confirmed that p-NP can be photo-ionized to produce its radical cation (p-NP(+)) and hydrated electron (e(aq)(-)) with a quantum yield of 0.52. In neutral solution p-NP(+) will be quickly deprotonated to form its phenoxyl radical (p-NP) which will react with oxygen to promote the breakage of benzene ring of p-NP. The degradation efficiency of p-NP exposed to 254 nm UV is as low as commonly reported. However, oxygen could improve the photo-degradation efficiency, which is due to the reaction of oxygen with p-NP. The reaction between oxygen and p-NP has been experimentally confirmed both in LFP and in pulse radiolysis.

Retention of nonionic organic compounds on thermally treated soils.

To achieve a higher efficiency of thermal remediation of soil contaminated with organic compounds, the retention mechanisms of organic compounds on thermally treated soil need to be understood adequately. In this study, a soil-column gas chromatography approach was developed to determine the soil-air partition coefficients (K(SA)) at 300 degrees C for a diverse set of nonionic organic compounds bearing many different functional groups; and the retention mechanisms of these organic compounds on two typical soils, isohumisols and ferralisols, were characterized using a polyparameter linear free energy relationship (pp-LFER). The K(SA) values (mL g(-1)) of typical volatile organic compounds (VOCs) with lower boiling points were <1.5 and in some cases even below 1.0, suggesting the rapid removal of VOCs from soils at 300 degrees C. Moreover, the K(SA) values were found to be a strong function of the soil-column temperature T (K), and be almost independent of the carrier-gas flow rate. Significant differences in molecular interactions were noted among various soil-solute pairs. The relative contributions of nonspecific van der Waals forces to the retention of test polar solutes were higher on isohumisols than on ferralisols. In contrast to the reported pp-LFER models for natural soils and soil components at normal environmental temperatures, our results suggest that elevated temperature remarkably reduces H-bond interactions between polar organic compounds and the soil matrix, thus allowing accelerated desorption of polar organic compounds from soils during thermal treatment.