Simultaneous photocatalytic degradation and SERS detection of tetracycline with self-sustainable and recyclable ternary PI/TiO2/Ag flexible microfibers.

Facile and efficient photocatalysts using sunlight, as well as fast and sensitive surface-enhanced Raman spectroscopy (SERS) substrates, are urgently needed for practical degradation of tetracycline (TC). To meet these requirements, a new paradigm for PI/TiO2/Ag organic‒inorganic ternary flexible microfibers based on semiconducting titanium dioxide (TiO2), the noble metal silver (Ag) and the conjugated polymer polyimide (PI) was developed by engineering a simple method. Under sunlight, the photocatalytic characteristics of the PI/TiO2/Ag flexible microfibers containing varying amounts of Ag quantum dots (QDs) were evaluated with photocatalytic degradation of TC in aqueous solution. The results demonstrated that the amount of Ag affected the photocatalytic activity. Among the tested samples, PI/TiO2/Ag-0.07 (93.1%) exhibited a higher photocatalytic degradation rate than PI/TiO2 (25.7%), PI/TiO2/Ag-0.05 (77.7%), and PI/TiO2/Ag-0.09 (63.3%). This observation and evaluation conducted in the present work strongly indicated a charge transfer mechanism. Moreover, the PI/TiO2/Ag-0.07 flexible microfibers exhibited highly sensitive SERS detection, as demonstrated by the observation of the Raman peaks for TC even at an extremely low concentration of 10-10 moles per liter. The excellent photocatalytic performance and SERS detection capability of the PI/TiO2/Ag flexible microfibers arose from the Schottky barrier formed between Ag and TiO2 and also from the outstanding plasmonic resonance and visible light absorptivity of Ag, along with immobilization by the PI. The successful synthesis of PI/TiO2/Ag flexible microfibers holds significant promise for sensitive detection and efficient photocatalytic degradation of antibiotics.

Highly Efficient and Reusable PI/TiO2 Organic-Inorganic Microfibers for Sustainable Photocatalytic Degradation of Multiple Organic Pollutants under Simulated Sunlight.

Herein, a series of polyimide (PI)/titanium dioxide (TiO2) organic-inorganic flexible composite microfibers with high photocatalytic performance and good reusability were prepared by combining electrospinning technology and a hydrothermal method. Under simulated sunlight, the photocatalytic characteristics of the as-prepared PI nanofibers, TiO2 nanorods, and PI/TiO2 microfibers were evaluated with photocatalytic degradation of Rhodamine B (RhB) solution. Among the tested samples, PI/TiO2-3 mL hydrochloric acid-160 °C-14 h (PI/TiO-3-160-14) (100%) exhibited a superior photocatalytic degradation rate compared to pure PI (84.0%) and TiO2 (62.2%). The enhancement of the photocatalytic performance was attributed to the Z-scheme heterojunction mechanism. When the interface was irradiated by simulated sunlight, the band edge bending, built-in electric field, and Coulomb interaction synergistically facilitated the separation and transport of electron-hole pairs in the heterojunction. This enhanced the oxidation and reduction abilities of the valence and conduction bands of PI/TiO2. These results were adequately verified by X-ray photoelectron spectroscopy (XPS) analyses and radical trapping experiments. Additionally, PI/TiO2 microfibers also demonstrated excellent photocatalytic activity toward methylene blue (MB, 81.4%), methyl orange (MO, 95.9%), and malachite green (KG, 98.9%), underscoring the versatile applicability of PI/TiO2. Further supplementary investigations illustrated that PI/TiO2 microfibers also possess excellent photostability during our extensive recycling photocatalytic experiments.

Fast Depolymerization of PET Bottle Mediated by Microwave Pre-Treatment and An Engineered PETase.

Invited for this month's cover is the groups of Prof. Minna Hakkarainen, Prof. István Furó and Assoc. Prof. Per-Olof Syrén at KTH Royal Institute of Technology. The image shows how microwave irradiation is an efficient pre-treatment method of polyethylene terephthalate (PET) for subsequent biocatalytic depolymerization. The Research Article itself is available at 10.1002/cssc.202300742.

Fast Depolymerization of PET Bottle Mediated by Microwave Pre-Treatment and An Engineered PETase.

Recycling plastics is the key to reaching a sustainable materials economy. Biocatalytic degradation of plastics shows great promise by allowing selective depolymerization of man-made materials into constituent building blocks under mild aqueous conditions. However, insoluble plastics have polymer chains that can reside in different conformations and show compact secondary structures that offer low accessibility for initiating the depolymerization reaction by enzymes. In this work, we overcome these shortcomings by microwave irradiation as a pre-treatment process to deliver powders of polyethylene terephthalate (PET) particles suitable for subsequent biotechnology-assisted plastic degradation by previously generated engineered enzymes. An optimized microwave step resulted in 1400 times higher integral of released terephthalic acid (TPA) from high-performance liquid chromatography (HPLC), compared to original untreated PET bottle. Biocatalytic plastic hydrolysis of substrates originating from PET bottles responded to 78 % yield conversion from 2 h microwave pretreatment and 1 h enzymatic reaction at 30 °C. The increase in activity stems from enhanced substrate accessibility from the microwave step, followed by the administration of designer enzymes capable of accommodating oligomers and shorter chains released in a productive conformation.

Long non-coding RNAs regulate heavy metal-induced apoptosis in embryo-derived cells.

Heavy metal pollution has been a worldwide prevalent problem, and particularly a threat to ecosystem integrity and animals' health. Previous studies on the mechanisms of heavy metal toxicity have focused on protein-coding genes, whereas most genomic transcripts are long non-coding RNAs (lncRNAs). Although lncRNAs are known to play important regulatory roles in biological processes, their role in heavy metal stress regulation is still not fully understood. We here developed an insect embryo cell model for studying metal toxicity and the underlying regulatory mechanisms. We performed genome-wide screening and functional characterization of lncRNAs induced by two essential and two non-essential heavy metals in Drosophila embryo-derived S2 cells. We identified 4894 lncRNAs, of which 1410 were novel. Forty-one lncRNAs, together with 328 mRNAs, were induced by all the four heavy metals. LncRNA-mRNA co-expression network and pathway enrichment analysis showed that detoxification metabolism, circadian rhythm, and apoptosis regulation pathways were activated in response to heavy metal stress. LncRNA CR44138 was remarkably upregulated in cells exposed to the four heavy metals and was associated with the apoptosis pathway. Expression interference confirmed that CR44138 aggravated cytotoxicity-induced apoptosis in cells under heavy metals stress. This study highlights the important role of lncRNAs in regulating the cellular response to heavy metals. This study also lays the foundation for discovering the novel regulatory mechanisms and developing diagnostic biomarkers of the toxic effects of heavy metal pollutants on organisms.

Correlation between postpartum pelvic floor dysfunction and vaginal microecological imbalance in late pregnancy. / äº§åŽç›†åº•åŠŸèƒ½éšœç¢ä¸Žå¦Šå¨ æ™šæœŸé˜´é“å¾®ç”Ÿæ€å¤±è¡¡çš„ç›¸å ³æ€§ï¼ˆè‹±æ–‡ï¼‰.

OBJECTIVES: Pelvic floor dysfunction (PFD) seriously affects women's physical and mental health. Pregnancy and childbirth are recognized as high-risk factors for PFD, and studies have shown that vaginal microenvironmental disorders can promote the development of pelvic organ prolapse. In this study, we intend to investigate whether the changes in vaginal microecology during pregnancy affect the pelvic floor function and participate in the development of postpartum PFD, and provide a basis for the prevention and treatment of PFD. METHODS: A total of 358 full-term mothers who delivered in Third Xiangya Hospital, Central South University from November 2019 to April 2020 were selected and underwent review 6 to 8 weeks after delivery. The pelvic floor structures were examined using pelvic floor ultrasound, and ultrasound values were measured at rest and at maximum Valsalva maneuver. One hundred and seventy women with PFD were assigned in a PFD group, and 188 women without PFD were assigned in a control group. The clinical data of all mothers were collected, and the clinical data and the results of microecological testing for vaginal secretions after 36 weeks of gestation and before delivery were compared between the 2 groups. The correlation of PFD with leucorrhoea cleanliness, lactobacillus level, bacterial vaginosis (BV), and vulvovaginal candidiasis (VVC) was analyzed, and logistic regression analysis was used to screen for independent risk factors for PFD. RESULTS: The incidences of VVC, BV, Lactobacillus vaginalis deficiency, and leucorrhoea cleanliness ≥III° were all higher in the PFD group than those in the control group (P<0.05). Among them, leukocyte cleanliness ≥III°and lack of Lactobacilli in the vagina were independent risk factors for the development of PFD, while VVC and BV were not independent risk factors for the development of PFD. CONCLUSIONS: Postpartum PFD is related to vaginal microecological imbalance in late pregnancy, among which Lactobacillus vaginalis deficiency and leucorrhoea cleanliness ≥III° are independent risk factors for the occurrence of PFD. Therefore, pregnant women with Lactobacillus vaginalis deficiency and leucorrhoea cleanliness ≥III° in late pregnancy should pay attention to the occurrence of postpartum PFD, and early diagnosis and effective intervention of postpartum PFD should be enhanced.

Pinene-Based Oxidative Synthetic Toolbox for Scalable Polyester Synthesis.

Generation of renewable polymers is a long-standing goal toward reaching a more sustainable society, but building blocks in biomass can be incompatible with desired polymerization type, hampering the full implementation potential of biomaterials. Herein, we show how conceptually simple oxidative transformations can be used to unlock the inherent reactivity of terpene synthons in generating polyesters by two different mechanisms starting from the same α-pinene substrate. In the first pathway, α-pinene was oxidized into the bicyclic verbanone-based lactone and subsequently polymerized into star-shaped polymers via ring-opening polymerization, resulting in a biobased semicrystalline polyester with tunable glass transition and melting temperatures. In a second pathway, polyesters were synthesized via polycondensation, utilizing the diol 1-(1'-hydroxyethyl)-3-(2'-hydroxy-ethyl)-2,2-dimethylcyclobutane (HHDC) synthesized by oxidative cleavage of the double bond of α-pinene, together with unsaturated biobased diesters such as dimethyl maleate (DMM) and dimethyl itaconate (DMI). The resulting families of terpene-based polyesters were thereafter successfully cross-linked by either transetherification, utilizing the terminal hydroxyl groups of the synthesized verbanone-based materials, or by UV irradiation, utilizing the unsaturation provided by the DMM or DMI moieties within the HHDC-based copolymers. This work highlights the potential to apply an oxidative toolbox to valorize inert terpene metabolites enabling generation of biosourced polyesters and coatings thereof by complementary mechanisms.

Determining antimicrobial resistance profiles and identifying novel mutations of Neisseria gonorrhoeae genomes obtained by multiplexed MinION sequencing.

Gonorrhea is one of the most common sexually transmitted diseases worldwide. To cure infection and prevent transmission, timely and appropriate antimicrobial therapy is necessary. Unfortunately, Neisseria gonorrhoeae, the etiological agent of gonorrhea, has acquired nearly all known mechanisms of antimicrobial resistance (AMR), thereby compromising the efficacy of antimicrobial therapy. Treatment failure resulting from AMR has become a global public health concern. Whole-genome sequencing is an effective method to determine the AMR characteristics of N. gonorrhoeae. Compared with next-generation sequencing, the MinION sequencer (Oxford Nanopore Technologies (ONT)) has the advantages of long read length and portability. Based on a pilot study using MinION to sequence the genome of N. gonorrhoeae, we optimized the workflow of sequencing and data analysis in the current study. Here we sequenced nine isolates within one flow cell using a multiplexed sequencing strategy. After hybrid assembly with Illumina reads, nine integral circular chromosomes were obtained. By using the online tool Pathogenwatch and a BLAST-based workflow, we acquired complete AMR profiles related to seven classes of antibiotics. We also evaluated the performance of ONT-only assemblies. Most AMR determinants identified by ONT-only assemblies were the same as those identified by hybrid assemblies. Moreover, one of the nine assemblies indicated a potentially novel antimicrobial-related mutation located in mtrR which results in a frame-shift, premature stop codon, and truncated peptide. In addition, this is the first study using the MinION sequencer to obtain complete genome sequences of N. gonorrhoeae strains which are epidemic in China. This study shows that complete genome sequences and antimicrobial characteristics of N. gonorrhoeae can be obtained using the MinION sequencer in a simple and cost-effective manner, with hardly any knowledge of bioinformatics required. More importantly, this strategy provides us with a potential approach to discover new AMR determinants.

Native protein delivery into rice callus using ionic complexes of protein and cell-penetrating peptides.

Direct protein delivery into intact plants remains a challenge for the agricultural and plant science fields. Cell-penetrating peptide (CPP)-mediated protein delivery requires the binding of CPPs to a protein to carry the protein into the cell through the cell wall and lipid bilayer. Thus, we prepared ionic complexes of a CPP-containing carrier peptide and a cargo protein, namely, Citrine yellow fluorescent protein, and subsequently studied their physicochemical properties. Two types of carrier peptides, BP100(KH)9 and BP100CH7, were investigated for delivery efficiency into rice callus. Both BP100(KH)9 and BP100CH7 successfully introduced Citrine protein into rice callus cells under pressure and vacuum treatment. Moreover, delivery efficiency varied at different growth stages of rice callus; 5-day rice callus was a more efficient recipient for Citrine than 21-day callus.

Safety of early oral feeding after total laparoscopic radical gastrectomy for gastric cancer (SOFTLY): Study protocol for a randomized controlled trial.

BACKGROUND: Gastric cancer is the third most common cause of cancer-related deaths and has the fifth highest incidence worldwide, especially in eastern Asia, central and Eastern Europe, and South America. Currently, surgery is the only curative treatment for gastric cancer; however, there is an increasing trend toward laparoscopic radical gastrectomy. Early oral feeding (EOF) has been shown to benefit clinical outcomes compared with open gastrectomy under conditions of enhanced recovery after surgery. There are a lack of guidelines and evidence for the safety and feasibility of EOF in patients undergoing laparoscopic radical gastrectomy. Thus, a prospective randomized trial is warranted. METHODS/DESIGN: The EOF after total laparoscopic radical gastrectomy (SOFTLY) study is a single-center, parallel-arm, non-inferiority randomized controlled trial which will enroll 200 patients who are pathologically diagnosed with gastric cancer and undergo laparoscopic radical gastrectomy. The primary endpoint, incidence of anastomotic leakage, is based on 1.9% in the control group in the CLASS-01 study. The patients will be randomized (1:1) into two groups: the EOF group will receive a clear liquid diet on post-operative day 1 (POD1) and the delayed oral feeding (DOF) group will receive a clear liquid diet on post-operative day 4 (POD4). The demographic and pathologic characteristics will be recorded. Total and oral nutritional intake, general data, total serum protein, serum albumin, blood glucose, and temperature will be recorded before surgery and at the time of hospitalization. Adverse events will also be recorded. The occurrence of post-operative fistulas, including anastomotic leakage, will be recorded as the main severe post-operative adverse event and represent the primary endpoint. DISCUSSION: The safety and feasibility of EOF after gastrectomy has not been established. The SOFTLY trial will be the first randomized controlled trial involving total laparoscopic radical gastrectomy, in which the EOF group (POD1) will be compared with the DOF group (POD4). The results of the SOFTLY trial will provide data on the safety and feasibility of EOF after total laparoscopic radical gastrectomy. TRIAL REGISTRATION: Chinese Clinical Trial Registry, ChiCTR-IOR-15007660 . Registered on 28 December 2015. The study has full ethical and institutional approval.

Safety of early oral feeding after total laparoscopic radical gastrectomy for gastric cancer (SOFTLY-1): a single-center randomized controlled trial.

Objectives: The aim of this study is to explore the safety and feasibility of early oral feeding (EOF) on short-term postoperative outcomes. Trial design: A prospective randomized non-inferiority trial. Materials and methods: From August 27, 2015 to March 31, 2017, 100 consecutive patients with gastric cancer in Xijing Hospital were recruited. Patients undergoing total laparoscopic radical gastrectomy (TLRG) received either EOF group or delayed oral feeding (DOF group). The endpoints were anastomotic leakage, the recovery of bowel function, the postoperative complications and costs. The process of randomization used a computer-generated sequence that was kept in a sealed envelope by a nurse that did not participate in the trial. None of the participants, administrators of interventions and those assessing outcomes was blinded. Results: Ultimately, 51 patients were in EOF group and 49 in DOF group, which both are comparable. The postoperative hospital stay in EOF group was significantly lower than DOF group (5.18±1.47 days vs 6.18±2.46 days, P=0.016). Furthermore, there was a trend for a reduction in the time of first flatus (10.3 hrs) and defecation (12.7 hrs) in EOF group compared to DOF group, but it was not statistically significant. Meanwhile, there were no significant differences in postoperative complications between two groups. One patient in the EOF group developed a fistula in the surgical remnant, which was recorded as other leakages; there was no difference between the two groups (P=0.582). Conclusion: EOF does not seem to be more harmful than DOF, and might significantly improve the short-term outcomes for patients receiving TLRG.

Ruthenium(II) salicylate complexes inducing ROS-mediated apoptosis by targeting thioredoxin reductase.

Thioredoxin reductase (TrxR), a major component of the thioredoxin system, makes a critical role in regulating cellular redox signaling and is found to be overexpressed in many human cancer cells. TrxR has become an attractive target for anticancer agents. In this work, three Ru(II) complexes with salicylate as ligand, [Ru(phen)2(SA)] (phen = 1,10-phenanthroline, SA = salicylate, 1), [Ru(dmb)2(SA)] (dmb = 4,4'-dimethyl-2,2'-bipyridine, 2) and [Ru(bpy)2(SA)] (bpy = 2,2'-bipyridine, 3), were synthesized and characterized. The anticancer effect exerted by them was evaluated. Complex 1 was found to exhibit obvious anticancer activity, in comparison with cisplatin, against cancer cell lines, while displaying low toxicity to the normal cell line BEAS-2B. The mechanism of complex 1 cancer cell growth suppress was investigated in A549 cells. Complex 1 exerted its anticancer through inducing apoptosis and triggering cell cycle arrest at the G0/G1 phase. Complex 1 can selectively inhibit TrxR activity and thus promote the generation and accumulation of reactive oxygen species (ROS), which subsequently trigger mitochondrial dysfunction and DNA damage, activate oxidative stress-sensitive mitogen activated protein kinase (MAPK), and suppress the protein kinase B (PKB or AKT) signal pathway, resulting in apoptosis in A549 cells.

Comparison of catalytic properties of multiple ß-glucosidases of Trichoderma reesei.

Ten putative Trichoderma reesei ß-glucosidase (BGL) isozymes were heterologously expressed in Escherichia coli and Aspergillus oryzae and purified to homogeneity. Catalytic properties of nine enzymes which showed hydrolytic activity on cellobiose and p-nitrophenyl-ß-D-glucopyranoside (pNPG) were investigated. Three BGLs, encoded by the genes cel3A, cel3B, and cel3E, contained a predicted signal peptide, showed higher hydrolytic activity on cello-oligosaccharides than on pNPG, and preferred longer oligosaccharides. Another three putative extracellular BGLs, Cel3B, Cel3F, and Cel3G, and two intracellular enzymes, Cel3C and Cel3D, exhibited preference for pNPG. Intracellular Cel1A showed the highest affinity for cellobiose as a typical cellobiase. Four BGLs, Cel3A, Cel3B, Cel3E, Cel1A, that showed high activity against cello-oligosaccharides were capable of catalyzing transglycosylation reactions from cellobiose, leading to formation of cellotriose and isomeric glucobioses. While Cel3A, Cel3B, and Cel3E synthesized mainly gentiobiose, glycosyl transfer reactions of Cel1A led mainly to sophorose and laminaribiose. Conversion of cellobiose to sophorose by Cel1A reached about 3.6 and 10 % at 1 and 10 % cellobiose concentration, respectively. The formation and persistence of individual cellobiose isomers in incubation mixtures of four BGLs (Cel3A, Cel3B, Cel3E, and Cel1A) with cellobiose correlated well with the k cat values for isomeric glucobioses. Cel1A also showed the lowest sensitivity to inhibition by glucose. Based on all studied catalytic properties, Cel1A appears to be unambiguously the best candidate for site-directed mutations or directed evolution toward improvement of activity, thermostability, and, eventually, efficiency of sophorose synthesis.

Improvements in Glucose Sensitivity and Stability of Trichoderma reesei ß-Glucosidase Using Site-Directed Mutagenesis.

Glucose sensitivity and pH and thermal stabilities of Trichoderma reesei Cel1A (Bgl II) were improved by site-directed mutagenesis of only two amino acid residues (L167W or P172L) at the entrance of the active site. The Cel1A mutant showed high glucose tolerance (50% of inhibitory concentration = 650 mM), glucose stimulation (2.0 fold at 50 mM glucose), and enhanced specific activity (2.4-fold) compared with those of the wild-type Cel1A. Furthermore, the mutant enzyme showed stability at a wide pH range of 4.5-9.0 and possessed high thermal stability up to 50 °C with 80% of the residual activities compared with the stability seen at the pH range of 6.5-7.0 and temperatures of up to 40 °C in the wild-type Cel1A. Kinetic studies for hydrolysis revealed that the Cel1A mutant was competitively inhibited by glucose at similar levels as the wild-type enzyme. Additionally, the mutant enzyme exhibited substrate inhibition, which gradually disappeared with an increasing glucose concentration. These data suggest that the glucose stimulation was caused by relieve the substrate inhibition in the presence of glucose. To conclude, all the properties improved by the mutagenesis would be great advantages in degradation of cellulosic biomass together with cellulases.

[GoldMag particle-based chemiluminescence immunoassay for human high sensitive C-reactive protein].

OBJECTIVE: To develop a sensitive, accurate detection method for high sensitive C-reactive protein (hsCRP). METHODS: With the GoldMag particle as the solid phase carrier, horseradish peroxidase (HRP)-lunimo-H2O2 as the chemiluminescence reaction system, we established a chemiluminescent immunoassay for hsCRP detection. Linear range, sensitivity, precision, accuracy and other indicators were evaluated. hsCRP level of 233 clinical human serum specimens were determined and compared by two different methods: the GoldMag particle-based magnetic chemiluminescence enzyme-linked immunoassay established in this study, and the commercialized scattering immunoturbidimetric assay from Germany SIEMENS. RESULTS: The chemiluminescent immunoassay for hsCRP based on GoldMag particle had a good linear relationship between 0.15 mg/L and 25 mg/L (R(2)=0.9937), with the detection limit of 0.076 mg/L. The intra-assay precision was less than 10.00% and the inter-assay precision was less than 15.00%. The average recovery rate for accuracy was 97.80%. In the contrast experiment of 233 clinical human serum specimens, the results obtained using the approach established in this study showed a high correlation and consistency with scattering immunoturbidimetric assay from Germany SIEMENS. CONCLUSION: GoldMag particle-based magnetic chemiluminescence enzyme-linked immunoassay for hsCRP has been successfully developed.