Microecology of aerobic denitrification system construction driven by cyclic stress of sulfamethoxazole.

The construction of aerobic denitrification (AD) systems in an antibiotic-stressed environment is a serious challenge. This study investigated strategy of cyclic stress with concentration gradient (5-30 mg/L) of sulfamethoxazole (SMX) in a sequencing batch reactor (SBR), to achieve operation of AD. Total nitrogen removal efficiency of system increased from about 10 % to 95 %. Original response of abundant-rare genera to antibiotics was changed by SMX stress, particularly conditionally rare or abundant taxa (CRAT). AD process depends on synergistic effect of heterotrophic nitrifying aerobic denitrification bacteria (Paracoccus, Thauera, Hypomicrobium, etc). AmoABC, napA, and nirK were functionally co-expressed with multiple antibiotic resistance genes (ARGs) (acrR, ereAB, and mdtO), facilitating AD process. ARGs and TCA cycling synergistically enhance the antioxidant and electron transport capacities of AD process. Antibiotic efflux pump mechanism played an important role in operation of AD. The study provides strong support for regulating activated sludge to achieve in situ AD function.

Effects of combined antibiotics on nitrification, bacteria and antibiotic resistance genes in activated sludge: Insights from legacy effect of antibiotics.

The effect of combined antibiotics exposure on nitrogen removal, microbial community assembly and proliferation of antibiotics resistance genes (ARGs) is a hotspot in activated sludge system. However, it is unclear that how the historical antibiotic stress affects the subsequent responses of microbes and ARGs to combined antibiotics. In this study, the effects of combined sulfamethoxazole (SMX) and trimethoprim (TMP) pollution on activated sludge under legacy of SMX or TMP stress with different doses (0.005-30 mg/L) were investigated to clarify antibiotic legacy effects. Nitrification activity was inhibited under higher level of combined exposure but a high total nitrogen removal (∼70%) occurred. Based on the full-scale classification, the legacy effect of past antibiotic stress had a marked effect on community composition of conditionally abundant taxa (CAT) and conditionally rare or abundant taxa (CRAT). Rare taxa (RT) were the keystone taxa in the microbial network, and the responses of hub genera were also affected by the legacy of antibiotic stress. Nitrifying bacteria and genes were inhibited by the antibiotics and aerobic denitrifying bacteria (Pseudomonas, Thaurea and Hydrogenophaga) were enriched under legacy of high dose, as were the key denitrifying genes (napA, nirK and norB). Furthermore, the occurrences and co-selection relationship of 94 ARGs were affected by legacy effect. While, some shared hosts (eg., Citrobacter) and hub ARGs (eg., mdtD, mdtE and acrD) were identified. Overall, antibiotic legacy could affect responses of activated sludge to combined antibiotic and the legacy effect was stronger at higher exposure levels.

[Historical Antibiotic Stress Changed the Effects of Sulfamethoxazole and Trimethoprim on Activated Sludge: ARGs and Potential Hosts].

The co-exposure of antibiotics has important effects on antibiotic resistance genes (ARGs) and microbial community aggregation in wastewater treatment plants (WWTPs). However, it is unclear whether differences in historical antibiotic exposure stress can determine responses of microbes and ARGs to combined antibiotics. By selecting a high concentration (30 mg·L-1) of sulfamethoxazole (SMX) and trimethoprim (TMP) as historical exposure stress conditions, the effects of SMX and TMP-combined pollution on ARGs, bacterial communities, and their interactions were explored in short-term experiments. Based on high-throughput quantitative PCR, a total of 13 ARGs were detected, and the absolute abundance was 2.21-5.42 copies·µL-1 (logarithm, DNA, the same below). Among them, sul2, ermB, mefA, and tetM-01 were the main subtypes in the samples, and the absolute abundance was between 2.95 and 5.40 copies·µL-1. The combined contamination of SMX and TMP could cause the enrichment of ARGs and mobile genetic elements (MGEs); however, their effects on each subtype were different, and the historical legacy effect of SMX was higher than that of TMP. Under the different exposure histories, the co-occurrence and co-exclusion patterns existed between ARGs. Moreover, MGEs (especially intI-1) were significantly correlated with sulfonamides (sul1 and sul2), tetracyclines[tet(32)], and macrolide-lincosamide-streptogramin (MLSB) resistance genes (ermB). Based on the full-scale classification of microorganisms, it was found that the microbial community structure of various groups responded differently to combined pollution, and the conditionally abundant taxa (CAT) were obviously enriched. Thauera, Pseudoxanthomonas, and Paracoccus were the dominant resistant bacterial genera. Furthermore, a total of 31 potential hosts of ARGs were identified with network analysis, which were dominated with conditionally rare taxa (CRT). Particularly, Candidatus_Alysiosphaera and Fusibacter were positively correlated with most of the ARGs, being the common protentional hosts. Importantly, some rare genera (RT, Variibacter, Aeromonas, Cloacibacterium, etc.) were potential hosts of transposon IS613, which played an important role in the proliferation and spread of ARGs. In conclusion, this study revealed the legacy effects of historical antibiotic stress on ARGs and their hosts, which could provide new ideas and theoretical basis for reducing ARGs pollution in WWTPs.

Fates of antibiotic resistance genes and bacterial/archaeal communities of activated sludge under stress of copper: Gradient increasing/decreasing exposure modes.

Effect of copper (Cu) on antibiotic resistance genes (ARGs) and bacterial/archaeal community of activated sludge under gradient increasing (0.5-10 mg/L) or decreasing exposure (10-0.5 mg/L) modes was explored. Here, 29 genes were detected among 48 selected ARGs and mobile gene elements (MGEs). Two exposure modes showed dissimilar effects on ARGs and distribution was more affected by environmental concentrations of Cu, which promoted transmission of ARGs (multiple drug resistance and sulfonamide). Cellular protection was main resistance mechanism, which was less inhibited than efflux pumps. The tnpA-02, as main MGE, interacted closely with ARGs (sul2, floR, etc.). Gradient increasing exposure mode had more effects on bacterial/archaeal structure and composition. Bacteria were main hosts for specific ARGs and tnpA-02, while archaea carried multiple ARGs (cmx(A), adeA, etc.), and bacteria (24.24 %) contributed more to changes of ARGs than archaea (19.29 %). This study clarified the impacts of Cu on the proliferation and transmission of ARGs.

Application of Different Doses of Tranexamic Acid Plus Traditional Chinese Medicine in Hip Arthroplasty in Patients with Diabetes and Its Influence on Intraoperative Blood Loss and Postoperative Drainage.

Objective: To evaluate the efficacy of different doses of tranexamic acid plus traditional Chinese medicine (TCM) in hip arthroplasty in diabetic patients and the effect on intraoperative hemorrhage and postoperative drainage. Methods: One hundred patients admitted to our hospital from January 2019 to September 2021 were randomly divided into group B (n = 50) and group A (n = 50), and tranexamic acid was injected intravenously at a dose of 10 mg/kg and 20 mg/kg 30 min before skin incision, and then tranexamic acid 1.0 g was injected into the joint cavity through the drainage after incision closure, followed by 3 h of drainage clamping. The amount of blood loss, coagulation index, postoperative drainage, and incidence of venous thromboembolism (VTE) were compared between the groups. Results: Group A had significantly less total blood loss, dominant blood loss, and hidden blood loss than group B (P < 0.05). No significant difference in postoperative coagulation indexes and postoperative drainage flow was found between the two groups (P > 0.05). Serological examination results demonstrated no statistical difference in D-dimer (D-D) levels between the two groups. The absence of VTE in both groups was determined by imaging. Conclusion: Tranexamic acid is effective in reducing intraoperative hemorrhage in diabetic patients undergoing hip arthroplasty. The dose of 20 mg/kg outperforms 10 mg/kg in terms of clinical efficacy with a favorable safety profile, which can be applied according to the patient's actual condition.

The dissimilarity of antibiotic and quorum sensing inhibitor on activated sludge nitrification system: Microbial communities and antibiotic resistance genes.

Effects of antibiotics (azithromycin, AZM, 1-40 mg/L) and quorum sensing inhibitor (QSI, 2(5H)-furanone, 1-40 mg/L) combined pollution with environmental concentration of copper on bacterial/archaeal community and antibiotic resistance genes (ARGs) in activated sludge system were explored. QSI inhibited nitrification more obviously than AZM. AZM and QSI were synergistic inhibitions on bacterial diversity, and AZM inhibited bacterial compositions more than QSI. While, QSI had more impacts on archaeal diversity/compositions. Less interactions among bacteria and archaea communities with Aquimonas as keystone genus. Functional differences in bacteria/archaea communities were little, and AZM had more effects on metabolism. AZM mainly affected nitrifying bacteria (Candidatus Nitrospira nitrificans and Nitrosomonas). Specific denitrifying bacteria were enriched by AZM (Brevundimonas, 1.76-31.69%) and QSI (Comamonas, 0.61-9.61%), respectively. AZM enriched ARGs more easily than QSI and they were antagonistic to proliferation of ARGs. Bacteria were main hosts of ARGs (macrolide-lincosamide-streptogramin B, other/efflux, etc.) and archaea (Methanosphaerula, Methanolobus) carried multiple ARGs.

Impact of ciprofloxacin and copper combined pollution on activated sludge: Abundant-rare taxa and antibiotic resistance genes.

This study aimed to explore the impacts of ciprofloxacin (CIP, 0.05-40 mg/L) and copper (3 mg/L) combined pollution on nitrification, microbial community and antibiotic resistance genes (ARGs) in activated sludge system during stress- and post-effect periods. Higher CIP concentration inhibited nitrification and an average of 50% total nitrogen removal occurred under 40 mg/L of CIP pressure. The stress- and post-effects on bacterial diversity and structure were obviously distinct. Abundant genera were more sensitive to combined pollution than rare genera based on full-scale classification and conditionally rare or abundant taxa were keystone taxa in their interactions. Ammonia oxidation genes were inhibited under high CIP level, but some aerobic denitrifying bacteria (Thauera, Comamonas and Azoarcus) and key genes increased. 96 ARG subtypes were detected with complex positive relationships and their potential hosts (abundant-rare-functional genera) changed in two periods. This study highlights the different stress- and post-effects of combined pollution on activated sludge.

Impacts of combined pollution under gradient increasing and gradient decreasing exposure modes on activated sludge: Microbial communities and antibiotic resistance genes.

The responses of microbial communities and antibiotic resistance genes (ARGs) to azithromycin and copper combined pollution under gradient increasing (from 0.5 to 10 mg/L) and decreasing exposure (from 10 to 0.5 mg/L) modes were investigated. Nitrification was inhibited more obviously under gradient increasing exposure mode. Responses of archaeal community and function structure were more obvious than bacteria under both exposure modes. The dominant bacterial and archaeal compositions (Hyphomicrobium, Euryarchaeota, etc.) were affected by two exposure modes, except some rare archaea (Methanoregula and Methanosarcina). There were more positive correlations between bacteria and archaea, and Nitrospira was keystone genus. Ammonia-oxidizing archaea (0.37-3.06%) and complete ammonia oxidizers (Nitrospira_ENR4) were enriched, and Nitrososphaera_viennensis was closely related to denitrifying genes (napA/B, nosZ, etc.). 50 ARG subtypes were detected and specific ARG subtypes (aac, ImrA, etc.) proliferated in two exposure modes. Bacteria and archaea were common hosts for 24 ARGs and contributed to their shifts.

Response of microbial communities based on full-scale classification and antibiotic resistance genes to azithromycin and copper combined pollution in activated sludge nitrification laboratory mesocosms at low temperature.

This study aimed to investigate the short-term response of abundant-rare genera and antibiotic resistance genes (ARGs) to azithromycin (AZM, 0.05-40 mg/L) and copper (1 mg/L) combined pollution in activated sludge nitrification system at low temperature. Nitrification was as expected inhibited in stress- and post-effects periods under AZM concentration higher than 5 mg/L. Abundant and rare taxa presented dissimilar responses based on full-scale classification. Conditionally rare or abundant taxa (CRAT) were keystone taxa. Relative abundance of ammonia-oxidizing archaea increased, and three aerobic denitrifying bacteria (Brevundimonas, Comamonas and Trichococcus) were enriched (from 9.83% to 68.91% in total). Ammonia nitrogen assimilating into Org-N and denitrification may be nitrogen pathways based on predict analysis. 29 ARGs were found with more co-occurrence patterns and high concentration of AZM (greater than 5 mg/L) caused their proliferation. Importantly, expect for some abundant taxa, rare taxa, potential pathogens and nitrogen-removal functional genera were the main potential hosts of ARGs.

Thermogelling chitosan-based polymers for the treatment of oral mucosa ulcers.

Current treatments for oral mucosa-related ulcers use drugs to relieve pain and promote healing, but rarely consider drug resistance to bacterial infection in the microenvironment of the oral cavity or the prevention of bleeding from gingival mucosa ulcers. We herein report an injectable, thermogelling chitosan-based system to address these concerns. An aqueous solution of chitosan-based conjugates (chitosan-g-poly(N-isopropylacrylamide) [CS-g-PNIPAAM] including 1a [CS-g-PNIPAAM with less PNIPAAM] and 1b [CS-g-PNIPAAM with more PNIPAAM], and chitosan-g-poly(N-isopropylacrylamide)-g-polyacrylamide [CS-g-PNIPAAM-g-PAM] 3) could reversibly form semi-solid gels at physiological temperatures for easy application to oral cavity ulcer sites by injection. The chitosan-based conjugate thermogels prepared could inhibit both Gram-positive and Gram-negative bacteria and the two with higher chitosan and poly(N-isopropylacrylamide) contents (1a and 1b) promoted proliferation of gingival fibroblasts in vitro. These two thermogels also exhibited improved blood clotting in an in vivo rat study. Thermogels 1a and 1b effectively promoted ulcer healing and shortened ulcer healing times in an oral gingival mucosa ulcer model using Sprague Dawley (SD) rats. These thermogels showed no obvious toxicity to the main organs of SD rats undergoing gingival ulcer treatment. These results suggest that this antibacterial biomaterial could be a promising injectable therapeutic agent for the treatment for oral mucosa ulcers.

[Progress on treatment for patellofemoral arthritis].

As a common disease of knee joint disease, the diagnosis and treatment of patellofemoral arthritis has not clear clinical consensus at present, conservative treatment only has a certain value for the disease with early stage and single disease. With the continuous improvement of understanding of pathogenesis and advancement of surgical techniques, minimally invasive and joint replacement technology has been rapid development, more and more alternative treatment options could be chosen. Technique of osteotomy of tibial tuberosity and removal of patella at the early stage were seldom used. According to development stage of disease, and combined with age, economic capacity, patients considering knee joint functional requirements and other factors, the balance of soft tissue under arthroscopy and denervation for cartilage injury in elderly patients with grade I to III surgery is more appropriate, and joint replacement is effective for cartilage injury in elderly patients with grade IV. Early debate is focus on total knee arthroplasty whether exist excessive medical treatment, patellofemoral joint replacement meet to demand for replacement of single patellofemoral degeneration with improvement of prosthesis design. Due to technical difficulties of cartilage transplantation and anatomical characteristics of patellofemoral joint, report of application of cartilage transplantation for patellofemoral arthritis is less, but with continuous improvement of technology, cartilage transplantation will be a good method for improving clinical symptoms, reducing medical costs, putting off joint replacement time.

Thermoresponsive supramolecular micellar drug delivery system based on star-linear pseudo-block polymer consisting of ß-cyclodextrin-poly(N-isopropylacrylamide) and adamantyl-poly(ethylene glycol).

Chemotherapy is facing several limitations such as low water solubility of anticancer drugs and multidrug resistance (MDR) in cancer cells. To overcome these limitations, a thermoresponsive micellar drug delivery system formed by a non-covalently connected supramolecular block polymer was developed. The system is based on the host-guest interaction between a well-defined ß-cyclodextrin (ß-CD) based poly(N-isopropylacrylamide) star host polymer and an adamantyl-containing poly(ethylene glycol) (Ad-PEG) guest polymer. The structures of the host and guest polymers were characterized by 1H and 13C NMR, GPC and FTIR. Subsequently, they formed a pseudo-block copolymer via inclusion complexation between ß-CD core and adamantyl-moiety, which was confirmed by 2D NMR. The thermoresponsive micellization of the copolymer was investigated by UV-vis spectroscopy, DLS and TEM. At 37°C, the copolymer at a concentration of 0.2mg/mL in PBS formed micelles with a hydrodynamic diameter of ca. 282nm. The anticancer drug, doxorubicin (DOX), was successfully loaded into the core of the micelles with a loading level of 6% and loading efficiency of 17%. The blank polymer micelles showed good biocompatibility in cell cytotoxicity studies. Moreover, the DOX-loaded micelles demonstrated superior therapeutic effects in AT3B-1-N (MDR-) and AT3B-1 (MDR+) cell lines as compared to free DOX control, overcoming MDR in cancer cells.

Thermoresponsive Delivery of Paclitaxel by ß-Cyclodextrin-Based Poly(N-isopropylacrylamide) Star Polymer via Inclusion Complexation.

Paclitaxel (PTX), a hydrophobic anticancer drug, is facing several clinical limitations such as low bioavailability and drug resistance. To solve the problems, a well-defined ß-cyclodextrin-poly(N-isopropylacrylamide) star polymer was synthesized and used as a nanocarrier to improve the water solubility and aim to thermoresponsive delivery of PTX to cancer cells. The star polymer was able to form supramolecular self-assembled inclusion complex with PTX via host-guest interaction at room temperature, which is below the low critical solution temperature (LCST) of the star polymer, significantly improving the solubilization of PTX. At body temperature (above LCST), the phase transition of poly(N-isopropylacrylamide) segments induced the formation of nanoparticles, which greatly enhanced the cellular uptake of the polymer-drug complex, resulting in efficient thermoresponsive delivery of PTX. In particular, the polymer-drug complex exhibited better antitumor effects than the commercial formulation of PTX in overcoming the multi-drug resistance in AT3B-1 cells.

[Medial transposition of the radial nerve in steel plate internal fixation of lower segment fracture of humerus].

OBJECTIVE: To investigate the method of medial transposition of the radial nerve in plate fixation of lower segment fracture of humerus. METHODS: From January 2010 to December 2013,31 patients with medial transposition of the radial nerve in plate fixation of lower segment fracture of humerus, including 18 males and 13 females ranging in age from 26 to 58 years old with a mean of 37 years old. The time between injury and operation was 1 to 8 days with an average of 4.5 days. According to AO classification, 7 fractures were type A1, 3 fractures were type A2, 6 fractures were type A3, 2 fractures were type B1, 4 fractures were type B2, 2 fractures were type B3, 4 fractures were type C, 3 fractures were type C2. No patients had any signs of radial nerve injury. The results were evaluated with DASH (disability of arm-shoulder-hand) Questionnaire by the American Academy of Orthopedic Surgeons (AAOS) which 0 indicated normal upper extremity function, and 1 to 100 indicated varying degrees of damage to the function of the upper extremties. RESULTS: There was no neurologic complication or postoperative wound infection in this series. The followed-up period ranged form 8 to 15 months (means 11 months) postoperatively. The clinical outcomes were evaluated with DASH Questionnaire, the score before operation was 76.2±11.8, the final follow-up score was 8.2±7.4, the final follow-up score was significant higher than before operation (P<0.01). The function of the upper extremities recovered satisfactorily. CONSLUSION: The method of medial transposition of the radial nerve in plate fixation of lower segment fracture of humerus can avoid iatrogenic radial nerve injury effectively.

Effects of population size on reproductive success of the endangered and endemic species Primula merrilliana.

The reproductive ability related to the population size of the endangered and endemic species Primula merrilliana Schltr. was investigated. In 26 populations observed, only four contain more than 500 flowering individuals, whereas most of them (53.8%) consist of less than 100 flowering individuals. Though the ratio of pin and thrum plants keeps its balance at 1:1 for all populations, the frequency of pin and thrum flowers was significantly biased in most small populations. Population size strongly affected reproductive success; plants in small populations produced significantly fewer flowers and fruits per plant and fewer seeds per fruit, and therefore fewer seeds per plant. The floral density was another important factor that influenced the reproductive success of P. merrilliana, because four main reproductive success parameters (fruits per plant, seeds per fruit, seeds per plant, and the proportion of flowers setting fruit) were all positively correlated with floral density. The size of plants and the number of leaves per plant (measure of habitat quality) were not influenced by the variation of population size, suggesting that the reduced fecundity in small populations may not be a consequence of lower habitat quality. Inbreeding depression and pollen limitation as a result of less attractiveness in small populations are therefore likely explanations for these patterns.

A chiral luminescent Au16 ring self-assembled from achiral components.

A luminescent supramolecular chiral Au16 ring with 4.822 nm perimeter that self-assembled from a tetrameric array of achiral Au2 units is described. Intra- and intermolecular Au...Au interactions play an important role in directing its chiral self-assembly.

A calix[4]arene carceplex with four Rh2 4+ fasteners.

It is shown that a spheroidal carceplex can be assembled by linking two bowl-shaped calix[4]arenes via four dimetal units, (DAniF)(2)Rh(2) (DAniF = N,N'-di-p-anisylformamidinate), with a molecule (diethyl ether) or a cation (tetraethylammonium ion) trapped inside. The tetraethylammonium carceplex, 1b, has been characterized by X-ray crystallography, (1)H NMR, IR, and mass spectrometry. The tetraethylammonium ion fits snugly in the interior of the spheroidal carceplex. A two-fold axis of the tetrahedral cation coincides with the idealized four-fold axis of the cage, and the cation is disordered over two rotational orientations. Only one axial position on each dirhodium unit is occupied by a ligand, CH(3)CN or H(2)O. The carceplex is very stable, and the axial ligands can be exchanged in single crystals without disrupting the crystallinity of the samples. In this way, a red crystal of the complex with all axial positions occupied by acetonitrile can be transformed to a green crystal of the complex with two axial positions having acetonitrile and the other two having water by simply putting the crystal in contact with distilled water. The calix[4]arene used to make the carciplex structure is 25,26,27,28-tetra-n-propoxycalix[4]arene-5,11,17,23-tetracarboxylic acid. By employing 25,26,27,28-tetrapropoxy-5,17-dibromo-calix[4]arene-11,23-dicarboxylic acid, two 1:1 dimetal:calixarene compounds have also been made and characterized: 2, cis-Rh(2)(DAniF)(2)(calix)(CH(3)OH), and 3, cis-Mo(2)(DAniF)(2)(calix). The Rh-Rh distances in 1b are in the range of 2.410(2)-2.428(2) A, that in 2 is 2.4383(4) A, and the Mo-Mo distance in 3 is 2.0931(4) A.