Type I photodynamic antimicrobial therapy: Principles, progress, and future perspectives

The emergence of drug-resistant bacteria has significantly diminished the efficacy of existing antibiotics in the treatment of bacterial infections. Consequently, the need for finding a strategy capable of effectively combating bacterial infections has become increasingly urgent. Photodynamic therapy (PDT) is considered one of the most promising emerging antibacterial strategies due to its non-invasiveness, low adverse effect, and the fact that it does not lead to the development of drug resistance. However, bacteria at the infection sites often exist in the form of biofilm instead of the planktonic form, resulting in a hypoxic microenvironment. This phenomenon compromises the treatment outcome of oxygen-dependent type-II PDT. Compared to type-II PDT, type-I PDT is not constrained by the oxygen concentration in the infected tissues. Therefore, in the treatment of bacterial infections, type-I PDT exhibits significant advantages over type-II PDT. In this review, we first introduce the fundamental principles of type-I PDT in details, including its physicochemical properties and how it generates reactive oxygen species (ROS). Next, we explore several specific antimicrobial mechanisms utilized by type-I PDT and summarize the recent applications of type-I PDT in antimicrobial treatment. Finally, the limitations and future development directions of type-I photosensitizers are discussed. STATEMENT OF SIGNIFICANCE: The misuse and overuse of antibiotics have accelerated the development of bacterial resistance. To achieve the effective eradication of resistant bacteria, pathfinders have devised various treatment strategies. Among these strategies, type I photodynamic therapy has garnered considerable attention owing to its non-oxygen dependence. The utilization of non-oxygen-dependent photodynamic therapy not only enables the effective elimination of drug-resistant bacteria but also facilitates the successful eradication of hypoxic biofilms, which exhibits promising prospects for treating biofilm-associated infections. Based on the current research status, we anticipate that the novel type I photodynamic therapy agent can surmount the biofilm barrier, enabling efficient treatment of hypoxic biofilm infections.

[Associations of blood pressure change with change in foods' intake among adults with mild to moderate hypertension]

Objective: To explore the association between the intake and changes in various types of food and the changes in blood pressure in patients with mild to moderate hypertension. Methods: Mild to moderate hypertension participants with complete baseline and outcome data were included from DECIDE-Diet study, a multicenter, randomized controlled trial. Dietary records and blood pressure measurements at both 7-day run-in (baseline) and 28-day intervention phases were collected for enrolled participants. Blood pressure change was defined as the difference between blood pressure at the end of trial and the baseline blood pressure. Baseline intake of food was the average daily intake during the run-in period, and the intake increment was defined as the difference between the average intake during the trial period and the average intake during the run-in period. After adjusting for age, sex, study center, intervention groups, baseline body mass index (kg/m2), antihypertension medication use, and baseline total calorie intake, a linear regression model was used to analyze the associations of the before-after-intervention change in blood pressure with baseline intake and intake increment of foods. Results: A total of 258 patients with mild to moderate hypertension were included, including 133 males, aged (56.5±9.9) years. (1) After adjusting for confounding factors, there was no significant association between baseline intake of food and baseline blood pressure (all P>0.05). The blood pressure change was negatively associated with baseline intakes of tubers, vegetables, and vegetable oils but positively with baseline intake of meats; and was negatively associated with intake increment of whole grains and fish (all P<0.05). (2) The multiple linear regression analysis showed that baseline intake of vegetables (β=-0.021, P=0.004), vegetable oils (β=-0.260, P=0.002), and increment in intake of fish (β=-0.128, P=0.026) were all significantly associated with changes in systolic blood pressure; baseline intake of vegetables (β=-0.017, P=0.002), vegetable oils (β=-0.182, P=0.001), dairy products (β=0.021, P=0.022), and increment in intake of fish (β=-0.092, P=0.010) were all significantly associated with changes in diastolic blood pressure. Conclusion: Increasing the intake of whole grains, vegetables, vegetable oils, and fish and decreasing the intake of meat may be beneficial for blood pressure control in patients with mild to moderate hypertension.

A novel approach to modify Stenotrophomonas sp. D6 by regulating the salt composition in the growth medium: Enhanced removal performance of Cr(VI)

In this study, a novel and effective modified microbial reducing agent was developed to detoxify Cr(VI) from aqueous solutions. This was achieved by carefully controlling specific salt components in the growth medium. Based on the single-salt modification, several effective modified salts were selected and added to the medium for synergistic modification. The results showed that the synergistic modification with NH4Cl and KH2PO4 had the best detoxification effect on Cr(VI), reaching 98.5% at 100 mg/L Cr(VI), which was much higher than the 43.7% of the control (original Luria-Bertani medium). This enhancement was ascribed to the ability of NH4Cl and KH2PO4 to stimulate the growth of Stenotrophomonas sp. D6 promoted chromate reductase secretion. The protein content of the modified medium supernatant was significantly increased by 10.76% compared to that before modification. Based on the micro-characterization, the main process for the elimination of Cr(VI) is microbial reduction rather than biosorption. Most of the reduced Cr was found in the extracellular suspension, thereby suggesting that the primary reduction occurred outside the cells, whereas only a small fraction was detected intracellularly. Overall, this study provides a simple and effective method for microbial treatment of heavy metals in aqueous solutions.

Cytochrome c regulates hyphal morphogenesis by interfering with cAMP-PKA signaling in Candida albicans

In the human fungal pathogen Candida albicans, invasive hyphal growth is a well-recognized virulence trait. We employed transposon-mediated genome-wide mutagenesis, revealing that inactivating CTM1 blocks hyphal growth. CTM1 encodes a lysine (K) methyltransferase, which trimethylates cytochrome c (Cyc1) at K79. Mutants lacking CTM1 or expressing cyc1K79A grow as yeast under hyphae-inducing conditions, indicating that unmethylated Cyc1 suppresses hyphal growth. Transcriptomic analyses detected increased levels of the hyphal repressor NRG1 and decreased levels of hyphae-specific genes in ctm1Δ/Δ and cyc1K79A mutants, suggesting cyclic AMP (cAMP)-protein kinase A (PKA) signaling suppression. Co-immunoprecipitation and in vitro kinase assays demonstrated that unmethylated Cyc1 inhibits PKA kinase activity. Surprisingly, hyphae-defective ctm1Δ/Δ and cyc1K79A mutants remain virulent in mice due to accelerated proliferation. Our results unveil a critical role for cytochrome c in maintaining the virulence of C. albicans by orchestrating proliferation, growth mode, and metabolism. Importantly, this study identifies a biological function for lysine methylation on cytochrome c.

A review of struvite crystallization for nutrient source recovery from wastewater

Nutrient recovery from wastewater not only reduces the nutrient load on water resources but also alleviates the environmental problems in aquatic ecosystems, which is a solution to achieve a sustainable society. Besides, struvite crystallization technology is considered a potential nutrient recovery technology because the precipitate obtained can be reused as a slow-release fertilizer. This review presents the basic properties of struvite and the theory of the basic crystallization process. In addition, the possible influencing variables of the struvite crystallization process on the recovery efficiency and product purity are also examined in detail. Then, the advanced auxiliary technologies for facilitating the struvite crystallization process are systematically discussed. Moreover, the economic and environmental benefits of the struvite crystallization process for nutrient recovery are introduced. Finally, the shortcomings and inadequacies of struvite crystallization technology are presented, and future research prospects are provided. This work serves as the foundation for the future use of struvite crystallization technology to recover nutrients in response to the increasingly serious environmental problems and resource depletion.

Effects of incineration and pyrolysis on removal of organics and liberation of cathode active materials derived from spent ternary lithium-ion batteries

Removing organics via thermal treatment to liberate active materials from spent cathode sheets is essential for recovering lithium-ion batteries. In this study, the effects of incineration, N2 pyrolysis, and CO2 pyrolysis on the removal of organics and liberation of ternary cathode active materials (CAMs) were compared. The results indicated that the organics in the spent ternary cathode sheets comprised a residual electrolyte and polyvinylidene fluoride (PVDF) binder. Moreover, the organics could be removed to promote the liberation of CAMs via incineration, N2 pyrolysis, and CO2 pyrolysis. When the temperature was <200 °C, the chemical properties of the volatilized ester electrolyte remained unchanged during both N2 and CO2 pyrolysis, indicating that the electrolyte can be collected by controlling the pyrolysis temperature and condensation. Furthermore, PVDF binder decomposition occurred at 200-600 °C. The optimal temperatures of incineration, N2 pyrolysis, and CO2 pyrolysis were 550, 500, and 450 °C, respectively, and these treatments increased the liberation efficiency of CAMs from 81.49 % to 98.75 %, 99.26 %, and 97.98 %, respectively. In addition, heat-treated CAMs required less time to achieve adequate liberation. Following three thermal treatment processes, the sizes of the CAM particles were mainly concentrated in the ranges of 0.075-0.1 mm and <0.075 mm. Furthermore, for all types of CAMs examined, the Al concentration decreased from 1.09 % to <0.35 %, which increased the separation efficiency and improved the chemical metallurgical performance.

Process parameters and biological mechanism of efficient removal of Cd(II) ion from wastewater by a novel Bacillus subtilis TR1

The safe treatment of heavy metals in wastewater is directly related to the human health and social development. In this paper, a new biological strain has been isolated from electroplating wastewater, which can effectively remove metal ions in wastewater. The results of 16 S rDNA sequencing analysis and NCBI GenBank database comparison show that the strain belongs to a novel Bacillus genus and names Bacillus subtilis TR1 with the accession number of OL441606. The removal rate of Cd(II) reaches to 85.68% with the conditions of pH = 7, C_0Cd(II) = 20 mg L^-1, t = 48 h, m = 0.1 g, and T = 35 °C. The biological removal mechanism of Cd(II) is in-depth studied by FTIR and XRD combined with third-generation sequencing. The results indicate that Bacillus subtilis TR1 removes Cd(II) mainly through two synergistic pathways, namely, extracellular chemisorption and intracellular bioaccumulation: 1) The groups carried on the surface of the strain, such as -COOH, -NH, -OH and C-H, have good chemisorption properties for Cd(II) and easily form cadmium containing chelation (-COO-Cd(II), -N-Cd(II), etc.) with these groups. The appearance of TR1 strain changes from cylindrical to spherical after Cd(II) adsorption, which is due to the biotoxicity of Cd(II); 2) Cd(II) exchanges on the surface of TR1 strain with K and Na ions released from the intracellular cytoplasm and enters the cytoplasm under the transfer of biological transport medium. This part of Cd(II) is converted into its own components by anabolic enzymes and accumulates in the cytoplasm. These data provide a new biological agent for the efficient treatment of heavy metal ions in wastewater and enrich relevant theoretical knowledge.

Bioleaching and immobilizing of copper and zinc using endophytes coupled with biochar-hydroxyapatite: Bipolar remediation for heavy metals contaminated mining soils

Copper and zinc are toxic heavy metals in soils that require development of feasible strategies for remediation of contaminated soils around the mine areas. In this study, the processing conditions and mechanisms of immobilization and bioleaching for remediation of highly contaminated soils with heavy metals are investigated. Soil remediation is carried out using a bioleaching-immobilization bipolar method. The results show that LSE03 bacteria provide efficient leaching result and immobilization on Cu²⁺ and Zn²⁺. Among the bacterial metabolites, cis, cis-muconic acid and isovaleric acid play major roles in the bioleaching process. The bacterial extracellular polymeric substances are rich in a variety of organic acids that show a significant decrease in content after the adsorption process, indicating that all of these substances are involved in the binding of heavy metals. Characterization of the endophytes and immobilizing agents with FTIR, TEM-mapping, and XPS techniques reveal the ability of both bacteria and composites to adsorb Cu-Zn as well as the main functional groups of -OH, -COOH, -PO₄^3-, and -NH. According to the heavy metals species analyses, competitive adsorption experiments, and bioleaching desorption experiments, it is planned to carry out the bipolar remediation of contaminated soil through immobilization followed by bioleaching process. After bipolar remediation processing, 97.923% and 96.387% of available Cu and Zn are respectively removed. Soils fertility significantly increases in all cases. Our study provides a green, practical, and environmentally friendly treatment method for soils contaminated with high concentrations of heavy metals.

Comprehensive Interactome Analysis for the Sole Adenylyl Cyclase Cyr1 of Candida albicans

Cyr1, the sole adenylyl cyclase of the fungal pathogen Candida albicans, is a central component of the cAMP/protein kinase A signaling pathway that controls the yeast-to-hypha transition. Cyr1 is a multivalent sensor and integrator of various external and internal signals. To better understand how these signals are relayed to Cyr1 to regulate its activity, we sought to establish the interactome of Cyr1 by using stable isotope labeling by amino acids in cell culture (SILAC)-based quantitative proteomics to identify the proteins that coimmunoprecipitated with Cyr1. The method identified 36 proteins as candidates for authentic Cyr1-interacting partners, together with two known Cyr1-binding proteins, Cap1 and Act1. Fourteen identified proteins belonged to three functional groups, including actin regulation, cell wall components, and mitochondrial activities, that are known to play important roles in cell morphogenesis. To validate the proteomics data, we used biochemical and genetic methods to characterize two cell wall-related proteins, Mp65 and Sln1. First, coimmunoprecipitation confirmed their physical association with Cyr1. Second, deleting either MP65 or SLN1 resulted in severe defects in filamentation on serum plates. This study establishes the first Cyr1 interactome and uncovers a potential role for cell wall proteins in directly regulating Cyr1 activity to determine growth forms in C. albicans. IMPORTANCE A critical virulence trait of the human fungal pathogen Candida albicans is its ability to undergo the yeast-to-hypha transition in response to diverse environmental and cellular stimuli. Previous studies suggested that the sole adenylyl cyclase of C. albicans, Cyr1, is a multivalent signal sensor and integrator synthesizing cAMP to activate the downstream hypha-promoting events through the cAMP/protein kinase A pathway. To fully understand how Cyr1 senses and processes multiple stimuli to generate appropriate signal outputs, it was necessary to identify and characterize Cyr1-interacting partners. This study employed SILAC-based quantitative proteomic approaches and identified 36 Cyr1-associated proteins, many having functions associated with hyphal morphogenesis. Coimmunoprecipitation verified two cell surface proteins, Mp65 and Sln1. Furthermore, genetic and phenotypic analyses demonstrated the cAMP-dependent roles of these two proteins in determining hyphal growth. Our study establishes the first Cyr1 interactome and uncovers new Cyr1 regulators that mediate cell surface signals to influence the growth mode of C. albicans.

An emission-free controlled potassium pyrosulfate roasting-assisted leaching process for selective lithium recycling from spent Li-ion batteries

Recycling critical metals from spent Li-ion batteries (LIBs) is important for the overall sustainability of future batteries. This study reports an improved sulfation roasting technology to efficiently recycle Li and Co from spent LiCoO₂ LIBs using potassium pyrosulfate as sulfurizing reagent. By sulfation roasting, LiCoO₂ was converted into water-soluble lithium potassium sulfate and water-insoluble cobalt oxide. Under optimal conditions, 98.51% Li was leached in water, with a selectivity of 99.86%. More importantly, sulfur can be recirculated thoroughly, and the sulfur atomic efficiency can be significantly enhanced by controlling the amount of potassium pyrosulfate. Li ions from the water leaching process were recovered by chemical precipitation. Furthermore, application of this technology to other spent LIBs, such as LiMn₂O₄ and LiNi_0.5Co_0.2Mn_0.3O₂, verified its effectiveness for selective recovery Li. These findings can provide some inspiration for high efficiency and environmentally friendly recovery metal from spent LIBs.

Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

Inactivating the mannose-ethanolamine phosphotransferase Gpi7 confers caspofungin resistance in the human fungal pathogen Candida albicans

Understanding the molecular mechanisms governing antifungal resistance is crucial for identifying new cellular targets for developing new antifungal therapeutics. In this study, we performed a transposon-mediated genome-wide genetic screen in haploid Candida albicans to identify mutants resistant to caspofungin, the first member of the echinocandin class of antifungal drugs. A mutant exhibiting the highest resistance possessed a transposon insertion that inactivates GPI7, a gene encoding the mannose-ethanolamine phosphotransferase. Deleting GPI7 in diploid C. albicans caused similar caspofungin resistance. gpi7Δ/Δ cells showed significantly elevated cell wall chitin content and enhanced phosphorylation of Mkc1, a core component of the PKC-MAPK cell-wall integrity pathway. Deleting MKC1 suppressed the chitin elevation and caspofungin resistance of gpi7Δ/Δ cells, but overexpressing the dominant inactive form of RHO1, an upstream activator of PKC-MAPK signaling, did not. Transcriptome analysis uncovered 406 differentially expressed genes in gpi7Δ/Δ cells, many related to cell wall construction. Our results suggest that GPI7 deletion impairs cell wall integrity, which triggers the cell-wall salvage mechanism via the PKC-MAPK pathway independently of Rho1, resulting in the compensatory chitin synthesis to confer caspofungin resistance.

[Association between dietary vitamin A intake and gestational diabetes mellitus in the first trimester]

Objective: To investigate the relationship between dietary vitamin A intake and its sources in the first trimester and gestational diabetes mellitus (GDM). Methods: A prospective study was conducted to select women at 6-14 weeks of gestation in an obstetric clinic of a maternal and child health care medical institution in Chengdu in 2017. The types and quantities of food during the first trimester were collected by 3-day 24-hour dietary recalls. Dietary vitamin A intake was calculated based on the Chinese Food Composition Table (2018), and it was divided into animal and plant vitamin A intakes according to its food sources. An oral glucose tolerance test was performed at 24-28 weeks of gestation to diagnose GDM according to the Chinese guidelines for diagnosis and treatment of gestational diabetes mellitus (2014). According to the estimated average requirement (EAR) and recommended nutrient intake (RNI), dietary vitamin A intake was divided into low-level group (<EAR), medium-level group (EAR-RNI) and high-level group (>RNI). Animal and plant vitamin A intakes were divided into four groups (Q1-Q4) according to the quartile method, respectively. The association between dietary vitamin A intake, its different sources of vitamin A intake and GDM in the first trimester was analyzed by log-binomial regression models. Results: A total of 1 298 valid samples were finally included. The average dietary vitamin A intake, animal and plant vitamin A intakes in the first trimester were 341.1 (227.8-501.0) μgRAE/d, 139.3 (69.6-195.3) μgRAE/d and 184.2 (99.4-301.1) μgRAE/d, respectively. After adjusting for confounding factors, log-binomial regression analysis showed that the risk of GDM in high-level group of dietary vitamin A intake was lower than that in low-level group [RR (95%CI):0.53 (0.36-0.80)]. Pregnant women in the highest quartile of animal vitamin A intake had a lower risk of GDM than those in the lowest quartile [RR (95%CI):0.66 (0.47-0.95)]. No relationship between plant vitamin A intake and GDM was found. Conclusion: Dietary vitamin A intake in the first trimester is associated with the occurrence of GDM, and higher intake than RNI may reduce the risk of GDM. Higher vitamin A intake from animal-derived food is associated with decreased risk of GDM.

Singlet oxygen-dominated activation of peroxymonosulfate by passion fruit shell derived biochar for catalytic degradation of tetracycline through a non-radical oxidation pathway

Waste-derived biochar has been emerged as promising catalysts to activate peroxymonosulfate (PMS) for the degradation of organic contaminants. Herein, passion fruit shell derived biochar (PFSC) was prepared by a one-pot pyrolysis method and used as a metal-free catalyst to activate PMS for the degradation of tetracycline hydrochloride (TC). The batch experiments indicated that the pyrolysis temperature could influence the efficiency of PFSC for the activation of PMS. In the PFSC-900 (prepared at 900 °C)/PMS system, the degradation rate of TC can reach 90.91%. The quenching test and electron paramagnetic resonance spectra revealed that the high catalytic performance of PFSC-900/PMS system was mainly attributed to the non-free radical reaction pathway containing a carbon bridge, and the TC degradation was controlled primarily by singlet oxygen-mediated oxidation. Moreover, the carboxyl group of ketones and the graphite-N atoms on PFSC-900 are the possible active sites of the non-free radical pathway including direct electron transfer or the formation of O₂^•-/¹O₂. This study not only shows a new type of biochar as an efficient catalyst for PMS activation but also provides a way of value-added reuse of passion fruit shell.

Ultrasonic power combined with seed materials for recovery of phosphorus from swine wastewater via struvite crystallization process

Recovering P via struvite crystallization is an effective way to utilize the resources in swine wastewater. At present, the main challenges of traditional struvite crystallization process are the long reaction time and insufficient removal efficiency. In this study, a novel method to promote struvite crystallization process through ultrasound (US) combined with seed materials is proposed to overcome these defects. We systematically study the effects of US, seed materials, and ultrasonic power on nutrient recovery. The experimental results show that under the conditions of pH 9.5 and MgCl₂:P molar ratio1.4:1, the addition of 2 g/L pre-synthesized struvite as the seed materials can increase the P removal rate to 91.56%, whereas, the addition of 80 W ultrasonic power for 15 min can make the P removal rate reach 94.18%. Meanwhile, the combination of US and struvite seed crystals can achieve a maximum P removal efficiency value of 97.66% in which 10 min for the reaction time is enough. The products are characterized using XRD, SEM, and FTIR to determine the phosphorus removal mechanism of ultrasonic power combined with seed induction. The shearing effect of US is found beneficial to affect the surface morphology of the seed crystals, which provides more nucleation sites to enhance crystal nucleation and growth. The removal efficiency comparison reveals that this combined technology performs an excellent removal effect.

Recycling of mullite from high-alumina coal fly ash by a mechanochemical activation method: Effect of particle size and mechanism research

High-alumina coal fly ash (HAFA) is a special solid waste since its alumina content can reach 40-50 wt%, which is seen as a potential resource for mullite material production. However, obtaining an ideal mullite material from HAFA is difficult because of its low Al₂O₃/SiO₂ mass ratio. In this work, the microstructure characteristics of HAFA were systematically analyzed by combining multiple characterization techniques. It was found that HAFA had a core-shell structure with a mullite/corundum crystal core and a silica-rich amorphous phase shell. The novel mechanochemical activation-desilication process was used to remove amorphous phase from HAFA and elevate the Al₂O₃/SiO₂ mass ratio. In particular, the effect of particle size after mechanical treatment and mechanism of the desilication process were extensively investigated. On decreasing the particle size, a high leaching rate of alumina was achieved during mechanochemical activation, thus generating a hydroxysodalite coating layer as desilication was suppressed, and the amorphous phase was effectively removed. The mineralogical phase of the desilicated HAFA is mainly mullite and corundum, and the Al₂O₃/SiO₂ mass ratio was elevated from 1.29 to 3.02. Mullite refractory obtained from the desilicated HAFA exhibited excellent physical properties. This study provides insights into further high-valued utilization of HAFA.

The effect of strength-endurance training on serum and urine metabolic profiles of female adolescent volleyball athletes

Aim

Limited investigations on metabolic responses to exercise training in female adolescent volleyball athletes exist. The aim of this study was to obtain serum and urine metabolite markers in female adolescent volleyball athletes within 2-week strength-endurance training using a metabolomics approach coupled with biochemical analysis, which would be potential biomarkers for evaluating the physiological state of athletes.

Methods

Twelve female adolescent volleyball athletes were recruited for 2-week strength-endurance training. Differential serum and urine metabolic profiles between the pre- and post-training group were obtained on gas chromatography coupled to mass spectrometry (GC-MS) and data subsequently underwent orthogonal partial least-squares analysis (OPLS).

Results

Strength-endurance training exerted a significant influence on the athletes' serum and urine metabolic profiles. The changed metabolites were primarily involved in energy metabolism, lipid metabolism and amino acids metabolism. Results support the hypothesis that female athletes displayed an increased propensity to oxidize lipids as the major energy source. Exposure to strength-endurance training also led to a significant increase in cortisol, but a decrease in testosterone, indicating disordered hormone adjustment. Exercise-induced oxidative stress occurred, as was evidenced by the decrease in reduced glutathione, and increases in blood malondialdehyde and oxidized glutathione. Since the muscle damage markers creatine kinase and lactate dehydrogenase did not show significant changes, the training might not cause cell membrane damage and the athletes did not cross the adaptive injury level.

Conclusion

By measurement of endogenous metabolites, the metabolomics study has the potential to reveal the global physiological changes in response to exercise training.

Senolytic agent Quercetin ameliorates intervertebral disc degeneration via the Nrf2/NF-κB axis

OBJECTIVE

Intervertebral disc degeneration (IDD) represents major cause of low back pain. Quercetin (QUE) is one of the approved senolytic agents. In this study, we evaluated the protective effects of QUE on IDD development and its underlying mechanism.

METHODS

Effects of senolytic agent QUE on the viability of nucleus pulposus cells (NPCs) were measured by CCK-8 assays and EdU staining. The senescence associated secreted phenotype (SASP) factors expressions were measured by qPCR, western blot, and ELISA; and NF-κB pathway was detected by immunofluorescence and western blot. Molecular docking was applied to predict the interacting protein of QUE; while Nrf2 was knocked down by siRNAs to confirm its role in QUE regulated senescence phenotype. X-ray, MRI, Hematoxylin-Eosin and Safranin O-Fast green staining were performed to evaluate the therapeutic effects of QUE on IDD in the puncture-induced rat model.

RESULTS

In in vitro experiments, QUE inhibited SASP factors expression and senescence phenotype in IL-1β-treated NPCs. Mechanistically, QUE suppressed IL-1β induced activation of the NF-κB pathway cascades; it was also demonstrated in molecular docking and knock down studies that QUE might bind to Keap1-Nrf2 complex to suppress NF-κB pathway. In vivo, QUE ameliorated the IDD process in the puncture-induced rat model.

CONCLUSIONS

Together the present work suggests that QUE inhibits SASP factors expression and senescence phenotype in NPCs and ameliorates the progression of IDD via the Nrf2/NF-κB axis, which supports senolytic agent QUE as a potential therapeutic agent for the treatment of IDD.

Effect of dehydration pathway on the surface properties of molecular crystals

Atomic force microscopy was used to determine roughness, elastic modulus and work function after thermally-induced and solvent-induced dehydration. These properties correlated with electric charging to provide insight into behaviour of bulk powders.

[Association between dietary glycemic load during first trimester and the risk of gestational diabetes mellitus: a prospective study]

Objective: To explore the effects of dietary glycemic load (GL) during first trimester on the risk of gestational diabetes mellitus (GDM). Methods: A prospective study was conducted among healthy women with singleton pregnancy at 8-14 weeks of gestation in a maternity out-patient clinic of maternal-and-child health care institution in Chengdu, Sichuan province. Information on dietary intake during the first trimester was collected through a 3-day 24-hour dietary recall. Glycemic index (GI) values were obtained from China Food Composition Tables (Standard Edition) and International Tables of Glycemic Index and Glycemic Load Values (2008). Dietary GL and GLs of staple foods were calculated based on GI values and the amount of carbohydrate consumed per day. Diagnostic criteria of GDM was followed the Guidelines for Diagnosis and Treatment of Pregnancy Diabetes in China (2014), and used on participants who underwent an oral glucose tolerant test during 24-28 weeks of gestation. Log-binomial regression models were used to explore the associations between both quartiles of dietary GL, GLs of staple foods and the risks of GDM,respectively. Results: The medians of dietary GL and GL of staple foods were 145.70 (113.23-180.85) and 121.05 (89.08-155.70), respectively. The median GL of both rice and tubers were 73.14 (43.89-107.50) and 3.43 (0.00-9.84), respectively. After adjusting for the age at pregnancy, pre-pregnancy body mass index and other confounding factors, results of log-binomial regressions analysis showed that when compared with the lowest quartile of dietary GL group, the third and highest quartiles of dietary GL groups increased the risk of GDM (RR=1.47, 95%CI: 1.20-1.80; RR=1.31, 95%CI: 1.04-1.64), respectively. Compared with the lowest quartile of GL of staple foods, the third and highest quartiles of GL of staple foods groups also increased the risk of GDM (RR=1.28, 95%CI: 1.04-1.58; RR=1.27, 95%CI: 1.02-1.60), respectively. The third and highest quartiles of GL of rice groups increased the risk of GDM (RR=1.30, 95%CI: 1.06-1.59; RR=1.28, 95%CI: 1.03-1.59), respectively, than the lowest quartile of GL of rice group. When compared with the lowest quartile of GL of tubers group, the highest quartile of GL of tubers group increased the risk of GDM (RR=1.30, 95%CI: 1.09-1.54). However, we did not notice the effects of wheat GL and coarse grain GL on the risk of GDM. Conclusions: A positive association was found between dietary glycemic load and the risk of GDM. Higher dietary glycemic load, especially in rice and tubers during first trimester, seemed to have increased the risk of GDM.

Synergistic removal of cadmium and organic matter by a microalgae-endophyte symbiotic system (MESS): An approach to improve the application potential of plant-derived biosorbents

Plant-derived materials as environmentally friendly biosorbents to remove heavy metals from wastewater have been extensively studied. However, the chemical oxygen demand (COD) increase caused by the plant-derived biosorbent has not been considered previously. In this study, water hyacinth was used as biosorbent to remove Cd(II) from wastewater. About 66% of Cd(II) was removed by the biosorbent with a maximum biosorption capacity (q_max) of 21.6 mg g^-1. However, the COD of the filtrate increased from 0 to 292 mg L^-1 during this process. Subsequently, endophytes, microalgae and the microalgae-endophyte symbiotic system (MESS) were assessed for the simultaneous Cd(II) and COD removal. Among these three systems, the MESS achieved the best performance. After 3 d of inoculation, the extent of total Cd(II) removal increased to 99.2% while COD decreased to 77 mg L^-1. This study provides a new insight into the application of a plant-derived biosorbent in combination with microalgae and endophytes for the effective treatment of heavy metal-bearing wastewater.

Porphyromonas gingivalis Promotes Oral Squamous Cell Carcinoma Progression in an Immune Microenvironment

Increasing evidence has revealed a significant association between microorganisms and oral squamous cell carcinoma (OSCC). Porphyromonas gingivalis, the keystone pathogen in chronic periodontitis, is considered an important potential etiologic agent of OSCC, but the underlying immune mechanisms through which P. gingivalis mediates tumor progression of the oral cancer remain poorly understood. Our cohort study showed that the localization of P. gingivalis in tumor tissues was related to poor survival of patients with OSCC. Moreover, P. gingivalis infection increased oral lesion multiplicity and size and promoted tumor progression in a 4-nitroquinoline-1 oxide (4NQO)–induced carcinogenesis mouse model by invading the oral lesions. In addition, CD11b+ myeloid cells and myeloid-derived suppressor cells (MDSCs) showed increased infiltration of oral lesions. Furthermore, in vitro observations showed that MDSCs accumulated when human-derived dysplastic oral keratinocytes (DOKs) were exposed to P. gingivalis, and CXCL2, CCL2, interleukin (IL)–6, and IL-8 may be potential candidate genes that facilitate the recruitment of MDSCs. Taken together, our findings suggest that P. gingivalis promotes tumor progression by generating a cancer-promoting microenvironment, indicating a close relationship among P. gingivalis, tumor progression of the oral cancer, and immune responses.

Synthesis of (ZrO2-Al2O3)/GO nanocomposite by sonochemical method and the mechanism analysis of its high defluoridation

A nanocomposite of (ZrO₂-Al₂O₃)/GO was successfully synthesized by a simple sonochemical method in this study. A special 3D network was formed in (ZrO₂-Al₂O₃)/GO, which produced a large surface area and good distribution of metal oxide nanoparticles. The as-synthesized (ZrO₂-Al₂O₃)/GO exhibits a maximum fluoride adsorption capacity of 62.2 mg/g, and an adsorption ability of 13.80 mg/g when the F^- equilibrium concentration is 1 mg/L, both of which are higher than most previously reported defluoridation adsorbents, indicating that it is among the top adsorbents. Large amounts of drinking water contaminated by F^- can be treated by (ZrO₂-Al₂O₃)/GO to meet the WHO limit, indicating the high potential for practical application of the adsorbent. Based on the experimental analysis, the origin of the high defluoridation performance and the adsorption mechanism were discussed in detail. Due to the simple preparation, easy operation and high performance, the adsorbent and the related sonochemical method are considered to be significant for developing highly effective adsorbents.

[Post-marketing multi-center safety surveillance of inactivated enterovirus A71 vaccine (Vero cell)]

Objective: To evaluate the post-marketing safety profiles of the inactivated enterovirus type 71 (EV-A71) vaccine (Vero cell) after routine inoculation. Methods: Eleven cities of Zhejiang Province, Fengtai district of Beijing, Qinnan district, two counties as Pingle and Pingguo of Guangxi Zhuang Autonomous Region, and Dongtai city of Jiangsu Province were selected as the field sites. A total of 45 239 subjects were enrolled in this study from children who seeked the vaccination of EV-A71 vaccine during the period from July, 2016 to June, 2018. Different sampling method were adopted in different sites. All vaccinated children were invited to participate in the study in Fengtai and Dongtai, however, systematic sampling method were adopted in other sites. Active surveillance was conducted and information about adverse reactions (ARs) occurred in 30 min, 3 d and 30 d following each dose of EV-A71 immunization was collected by field observation, phone-call or face-to-face interview. The incidence of ARs in different types, symptoms and grades were described. Results: In total, there were 45 239 children who received 71 243 doses EV-A71 vaccine. The overall incidence of ARs was 1.079% (769 doses), with the highest incidence of 1.182% (177/14 973) in 5-11 month group and the lowest incidence of 0.849% (18/2 119) in ≥ 36 month group among different age groups. There was a higher incidence in solicited ARs, which was 1.047% (746 doses). The incidences of grade 1 and grade 2 ARs were also higher, which were 0.404% (288 doses) and 0.554% (395 doses), respectively. No grade 4 ARs occurred. The doses of the first and the second vaccination was 40 736 and 30 507, respectively, and the incidences of ARs were 1.281% (522 doses) and 0.810% (247 doses). Also, the incidences of ARs were 0.091% (37 doses) and 0.043% (13 doses) in local, and 1.168% (476 doses) and 0.760% (232 doses) in system. The symptoms of ARs after the two doses of vaccination were basically the same. Redness at the injection site was the most common local ARs after each dose vaccination, with doses of 24 and 11, while fever was the most common systemic ARs, with doses of 362 and 190. Moreover, ARs mainly occurred in 30 min to 3 d after each dose vaccination, with incidence of 1.016% (414 doses) and 0.698% (213 doses) in the first and second dose, respectively. Conclusion: The ARs had a low incidence after vaccination in children and most were mild or moderate. EV-A71 vaccine with good safety is suitable for inoculation in a large scale.

Fluorine removal and calcium fluoride recovery from rare-earth smelting wastewater using fluidized bed crystallization process

As a regulated pollutant, fluorine compounds affect the health of millions of people all over the world. Their removal using a fluidized bed reactor (FBR) through crystallization process is a new method. Instead of chemical precipitation, which produces large amounts of sludge-containing wastewater hard to recover and treat. In this work, FBR was applied to a typical rare-earth smelting wastewater containing fluorine. Influence of different seed materials, seed size, and seed amounts on the fluorine removal and calcium fluoride recovery in the FBR were studied. When silica sand was used as the seed crystal and the amounts reached 30g, the concentration of fluorine in the actual wastewater decreased to 8.2 mg L^-1 or lower. The removal efficiency of fluorine and recovery ratio of calcium fluoride were obtained as 93.79% and 89.45%, respectively. The particle size of recovered calcium fluoride was about 1.5mm. The results show that FBR with silica sand as seed crystal is a feasible and economical method for removing fluorine and recovering calcium fluoride from rare-earth industrial wastewater.

Association between phosphodiesterase type 5 inhibitors use and risk of melanoma: a meta-analysis

This meta-analysis aimed to clarify the actual association between the phosphodiesterase type 5 inhibitors (PDE5-Is) use and the risk of melanoma in erectile dysfunction (ED) patients. A systematic literature search was conducted in online databases in October, 2016 to identify studies focusing on the association between PDE5-Is use and the risk of melanoma. Summarized multivariate adjusted risk ratios (RRs) and 95% confidence intervals (CIs) were calculated to assess the strength of associations. A total of six clinical trials containing more than one million participants were included. ED patients  using PDE5-Is shared a significant high risk of melanoma (RR=1.12, 95% CI=1.03-1.21, p=0.006). Positive associations were observed in all kinds of prescriptions: single prescription (RR=1.20, 95% CI=1.06-1.35, p=0.003), medium number of prescription (RR=1.15, 95% CI=1.01-1.30, p=0.03), and high number of prescription (RR=1.18, 95% CI=1.05-1.34, P=0.006). Additionally, PDE5-Is were also found to be significantly associated with increased risk of basal cell carcinoma (RR=1.14, 95% CI=1.09-1.19, p<0.00001). Our study indicates that PDE5-Is use could significantly increase the risk of melanoma and basal cell carcinoma. However, the risk of melanoma did not rise significantly with the increased number of prescriptions. Consequently, owing to the lack of information about other potential synergistic factors, it is difficult for us to make a solid conclusion that application of PDE5-Is is the direct cause of increased risk of melanoma. Their relationship needs to be validated by further evidences.

[Association between gestational weight gain and adverse pregnancy outcomes: a prospective study]

Objective: To explore the association between gestational weight gain (GWG) and adverse pregnancy outcomes. Methods: A prospective study was conducted among 1 220 healthy singleton pregnant women in the first trimester of pregnancy, from Chengdu city, Sichuan province. Pre-gestational body mass and other basic information were collected through a set of questionnaires. Weight at the last week before delivery was measured and GWG was classified by IOM criteria (2009). Related information on pregnancy outcomes was collected after delivery, through the hospital information system. Multiple non-conditional logistic regression models were used to test the association between GWG and adverse pregnancy outcomes. Results: In total, data on 1 045 pregnant women were analyzed. Compared with adequate GWG, excessive GWG was associated with the increased risks of cord entanglement and large for gestational age (OR=1.641, 95%CI: 1.197-2.252; OR=1.678, 95%CI: 0.132-2.488), respectively. Additionally, when compared with the adequate GWG, insufficient GWG was associated with the increased risk of preterm delivery (OR=3.189, 95%CI: 1.604-6.341). Conclusions: Both excessive and insufficient GWG appeared associated with the pregnancy outcomes. Weight monitoring should be strengthened for pregnant women to reduce related risks on adverse pregnancy outcomes.

G1 and S phase arrest in Candida albicans induces filamentous growth via distinct mechanisms

Candida albicans is an opportunistic fungal pathogen. In immunocompromised individuals, it can cause bloodstream infections with high mortality rates. The ability to switch between yeast and hyphal morphologies is a critical virulence factor of C. albicans. In response to diverse environmental cues, several signaling pathways are activated resulting in filamentous growth. Interestingly, cell cycle arrest can also trigger filamentous growth although the pathways involved are not well-understood. Here, we demonstrate that the cAMP-PKA pathway is involved in the filamentous growth caused by G1 arrest due to the depletion of the G1 cyclin Cln3 and S phase arrest due to hydroxyurea treatment. The downstream mechanisms involved in filamentation are different between the two cell cycle arrest phenomena. Cln3-depleted cells require HGC1 and UME6 for filamentous growth, but hydroxyurea-induced filamentation does not. Also, the hyphal repressor Nrg1 is not involved in the suppression of Cln3-depletion and hydroxyurea-induced filamentous growth. The findings highlight the complexity of the signaling networks that control filamentous growth in which different mechanisms downstream of the cAMP-PKA pathway are activated based on the nature of the inducing signals.

A long-acting pegylated recombinant human growth hormone (Jintrolong® ) in healthy adult subjects: Two single-dose trials evaluating safety, tolerability and pharmacokinetics

WHAT IS KNOWN AND OBJECTIVE

Jintrolong^® is a pegylated recombinant human growth hormone (rhGH) (PEG-rhGH) developed for weekly subcutaneous (sc) injection. The current human tolerability trial and pharmacokinetics (PK) trial evaluated the safety, tolerability and PK of single-dose Jintrolong^® injection in healthy adult subjects.

METHODS

Both trials were single-centre, randomized, open-label and single-dose studies. In the human tolerability trial, 34 healthy subjects were randomized to receive single-dose Jintrolong^® sc injection (0.01, 0.06, 0.2, 0.5 or 0.8 mg/kg) or placebo. In the PK study, 30 healthy male subjects were evenly randomized into 3 groups to receive single-dose Jintrolong^® sc injection (0.1, 0.2 or 0.4 mg/kg), and the subjects receiving 0.4 mg/kg Jintrolong^® were given a single sc injection of conventional rhGH (0.067 mg/kg) after a 14-day washout period. Safety and PK profiles of Jintrolong^® were evaluated.

RESULTS AND DISCUSSION

Jintrolong^® was well tolerated with no serious adverse events or local injection responses. The PK trial showed that the plasma growth hormone concentration elevated quickly and stayed at peak level between 12 and 48 hours post-Jintrolong^® injection, then decreased gradually back to baseline within 168 hours. Compared to single-dose conventional rhGH, Jintrolong^® at all doses demonstrated significantly longer half time and time to maximum plasma concentration, lower clearance and higher systemic drug exposure, indicating prolonged presence of GH in the subjects' circulation. Additionally, systemic exposure to Jintrolong^® increased in a dose-dependent manner.

WHAT IS NEW AND CONCLUSION

Single-dose Jintrolong^® injection was well tolerated in healthy adult subjects, and the maximum tolerable dose was no lower than 0.8 mg/kg. Jintrolong^® was long-acting with the potential for weekly administration.

Use of Haploid Model of Candida albicans to Uncover Mechanism of Action of a Novel Antifungal Agent

Antifungal agents for the treatment of Candida albicans infections are limited. We recently discovered a novel antifungal small molecule, SM21, with promising in vivo activity. Herein, we employed the newly developed C. albicans haploid toolbox to uncover the mechanism of action of SM21. Comprehensive RNA-Seq analyses of the haploid susceptible GZY803 strain revealed significant gene expression changes related to mitochondria when exposed to SM21. Mitochondrial structure visualization and measurement of ATP generation, reactive oxygen species (ROS) levels, and the antioxidant potential of SM21-treated and untreated GZY803, mitochondrial structure defective haploid mutant (dnm1Δ), and wild-type diploid SC5314 strains confirmed defects in mitochondria. Exploiting the advantage of C. albicans haploids as a single ploidy model, we further exposed GZY803 to repetitive treatments of SM21 in order to generate resistant mutants. Three colonies designated S3, S5 and S6, which displayed resistance to SM21, were isolated. All resistant strains exhibited enhanced transcriptomic responses for peptide and protein metabolism and secreted aspartate proteases (SAPs) activity under SM21 treatment compared to the parent strain GZY803. Consistently, supplementing the resistant strains, GZY803, and SC5314 with peptone, a form of digested peptides, decreased susceptibility to SM21. The present study demonstrates the usefulness of haploid C. albicans model in antifungal drug discovery. The findings will be invaluable to develop SM21 as a novel antifungal agent, which will benefit millions of patients suffering from Candida infections.

Thermal decomposition mechanisms of poly(vinyl chloride): A computational study

The studies on the pyrolysis mechanisms of waste PVC contribute to development and application of pyrolysis technology for mixed waste plastics. In the article, the thermal decomposition mechanisms of model compound of poly(vinyl chloride) (PVC) have been investigated by employing density functional theory methods at M06-2X/6-31++G(d,p) level in order to illuminate the elimination of HCl and the formation of hydrocarbons. Various possible pyrolysis paths for the formation of main products were proposed, and the thermodynamic and kinetic parameters in every path were calculated. The calculation results show that the HCl elimination can occur through the concerted reaction and the energy barrier of HCl elimination changes from 167.4 to 243.3 kJ/mol; allyl group can obviously reduce the activation energy of HCl elimination, and the branched-chain can lower the energy barrier of HCl elimination at the carbon sites near the branch chain; a free radical is more easily converted into aromatic compound through a series of isomerizations, cyclization and dehydrogenation; the conjugated polyene could be decomposed in parallel reaction channels: one is the evolution of aromatics, another is the formation of small molecule products. The above analysis is consistent with previous experimental results and analysis.

[Three-dimensional architecture of intraosseous vascular anatomy of the hamate: a micro-computed tomography study]

OBJECTIVE

To obtain three-dimensional intraosseous artery of the hamate and to provide the vascular anatomy basis of hamate fracture fixation.

METHODS

PbO (lead monoxide, Sinopharm Chemical Reagent Beijing Co. Ltd) was ground into particles less than 40 μm and suspended in turpentine oil (Chemical Reagent Beijing Co. Ltd) at ratios of 1 g : 1.5 mL, 1 g : 1 mL and 1 g : 0.5 mL. Three specimens were investigated. Brachial arteries were cannulated and perfused with lead-based contrast agent. Hamates were harvested and scanned using micro-computed tomography (microCT). The acquisition protocols were as follows: CT scan setup: total rotation [Degrees], 360; rotation steps, 360; X-ray detector setup: transaxial, 2048; axial, 2048; exposure time, 1 500 ms, Binning, 1; system magnification: high-med. X-ray tube setup: 80 kV, 500 mA current. The down-sampling factor used in the reconstruction was 2. The effective voxel size of the final image was 27.30 μm. The three-dimensional model of the hamate was generated and the distribution and pattern of vessels were evaluated.

RESULTS

There were abundant extraosseous vessels around the hamate. They were mainly running in the tendons and ligaments around the hamate. Four vascular zones were identified on the hamate surface. They were on the palmar platform of the hamate body, on the dorsal side, on the ulnar side and on the tip of hamulus, namely. There were anastomoses among 4 vascular zones. We did not observe any vessels penetrating through the articular cartilage. The extraosseous vessels of the vascular zones gave a number of intraosseous branches into the hamate. The hamate body received intraosseous blood supply from the dorsal, palmar and ulnar while the hamulus from the palmar, ulnar and hamulus tip. There were some intraosseous branches anastomosing with each other.

CONCLUSION

The extraosseous and intraosseous vessels of the hamate were more than what used to be considered. The hamate body and hamulus received blood supply from multiple directions and arteries anastomosed extensively both outside and inside the hamate, making it possible that the intraosseous perfusion survived after fracture. It is likely that the nonunion after the hamate fracture is not caused by the vascular damage but the malalignment of the fragments.

Maize Transposable Elements Ac/Ds as Insertion Mutagenesis Tools in Candida albicans

In nonmodel systems, genetic research is often limited by the lack of techniques for the generation and identification of gene mutations. One approach to overcome this bottleneck is the application of transposons for gene tagging. We have established a two-element transposon tagging system, based on the transposable elements Activator (Ac)/Dissociation (Ds) from maize, for in vivo insertion mutagenesis in the fungal human pathogen Candida albicans A nonautonomous Ds transposon carrying a selectable marker was constructed into the ADE2 promoter on chromosome 3 and a codon usage-adapted Ac transposase gene was inserted into the neutral NEUT5L locus on chromosome 5. In C. albicans cells expressing the transposase, the Ds element efficiently excised and reintegrated elsewhere in the genome, which makes the Ac/Ds transposons promising tools for saturating insertion mutagenesis in clinical strains of C. albicans.

A CRISPR-Cas9-based gene drive platform for genetic interaction analysis in Candida albicans

Candida albicans is the leading cause of fungal infections; yet, complex genetic interaction analysis remains cumbersome in this diploid pathogen. Here, we developed a CRISPR-Cas9-based 'gene drive array' platform to facilitate efficient genetic analysis in C. albicans. In our system, a modified DNA donor molecule acts as a selfish genetic element, replaces the targeted site and propagates to replace additional wild-type loci. Using mating-competent C. albicans haploids, each carrying a different gene drive disabling a gene of interest, we are able to create diploid strains that are homozygous double-deletion mutants. We generate double-gene deletion libraries to demonstrate this technology, targeting antifungal efflux and biofilm adhesion factors. We screen these libraries to identify virulence regulators and determine how genetic networks shift under diverse conditions. This platform transforms our ability to perform genetic interaction analysis in C. albicans and is readily extended to other fungal pathogens.

Antibacterial isoeugenol coating on stainless steel and polyethylene surfaces prevents biofilm growth

AIMS

Pathogenic bacteria can spread between individuals or between food items via the surfaces they share. Limiting the survival of pathogens on surfaces, therefore, presents an opportunity to limit at least one route of how pathogens spread. In this study, we propose that a simple coating with the essential oil isoeugenol can be used to circumvent the problem of bacterial transfer via surfaces.

METHODS AND RESULTS

Two commonly used materials, stainless steel and polyethylene, were coated by physical adsorption, and the coatings were characterized by Raman spectroscopy, atomic force microscopy and water contact angle measurements. We quantified and visualized the colonization of coated and uncoated surfaces by three bacteria: Staphylococcus aureus, Listeria monocytogenes and Pseudomonas fluorescens. No viable cells were detected on surfaces coated with isoeugenol.

CONCLUSIONS

The isoeugenol coating prepared with simple adsorption proved effective in preventing biofilm formation on stainless steel and polyethylene surfaces. The result was caused by the antibacterial effect of isoeugenol, as the coating did not diminish the adhesive properties of the surface.

SIGNIFICANCE AND IMPACT OF THE STUDY

Our study demonstrates that a simple isoeugenol coating can prevent biofilm formation of S. aureus, L. monocytogenes and P. fluorescens on two commonly used surfaces.