Chlorine disinfection to drinking water plays an important role in preventing and controlling waterborne disease outbreaks globally. Nevertheless, little is known about why it enriches the antibiotic ...resistance genes (ARGs) in bacteria after chlorination. Here, ARGs released from killed antibiotic-resistant bacteria (ARB), and culturable chlorine-injured bacteria produced in the chlorination process as the recipient, were investigated to determine their contribution to the horizontal transfer of ARGs during disinfection treatment. We discovered Escherichia coli, Salmonella aberdeen, Pseudomonas aeruginosa and Enterococcus faecalis showed diverse resistance to sodium hypochlorite, and transferable RP4 could be released from killed sensitive donor consistently. Meanwhile, the survival of chlorine-tolerant injured bacteria with enhanced cell membrane permeabilisation and a strong oxidative stress-response demonstrated that a physiologically competent cell could be transferred by RP4 with an improved transformation frequency of up to 550 times compared with the corresponding untreated bacteria. Furthermore, the water quality factors involving chemical oxygen demand (COD
), ammonium nitrogen and metal ions (Ca
and K
) could significantly promote above transformation frequency of released RP4 into injured E. faecalis. Our findings demonstrated that the chlorination process promoted the horizontal transfer of plasmids by natural transformation, which resulted in the exchange of ARGs across bacterial genera and the emergence of new ARB, as well as the transfer of chlorine-injured opportunistic pathogen from non-ARB to ARB. Considering that the transfer elements were quite resistant to degradation through disinfection, this situation poses a potential risk to public health.
Metal sulfonate frameworks offer unique properties and enormous potential for proton conduction. This review summarizes the recent progress in this topical field, including sulfonic acid coordinated ...MOFs, sulfate groups encapsulated MOFs and the composite membranes with these MOFs and so on. In-depth disscusses of the relationship of structures and proton conducting properties on such MOFs are presented.
Display omitted
•Proton conductive metal sulfonate frameworks were reviewed.•MOFs are classified and described according to the type of organic ligands.•Proton conductivity and conducting mechanism were discussed.•The future development trend of such MOFs is prospected.
Since the easy-to-design and customization of structures, guest accessibility of cavities, and functional tunability, MOFs have evolved into a burgeoning type of proton conductors. The sulfonic acid groups in MOFs can not only be used as proton sources but also can be involved in the formation of hydrogen bonds within the frameworks, which is extremely conducive to the efficient transfer of protons. In this review, recent advances of proton conductive sulfonate-based MOFs are provided covering sulfonic acid coordinated MOFs, MOFs encapsulated sulfate groups and the composite membrane contained these MOFs and so on. In-depth discussion of the relationship of structures and proton conducting properties on such MOFs is presented. Perspectives on the opportunities and challenges are proposed and highlighted.
•We observed eARG and iARG pollution in tap water with an evident seasonal pattern.•Extracellular TetC had the highest median level in tap water.•sul1 and sul2 were the most abundant iARGs in tap ...water.•iARG classes were related to the specific physicochemical index of water quality.
Antibiotic resistance genes (ARGs) have gained global attention due to their public health threat. Extracelluar ARGs (eARGs) can result in the dissemination of antibiotic resistance via free-living ARGs in natural environments, where they promote ARB transmission in drinking water distribution systems. However, eARG pollution in tap water has not been well researched. In this study, concentrations of eARGs and intracellular ARGs (iARGs) in tap water, sampled at Tianjin, China, were investigated for one year. Fourteen eARG types were found at the highest concentration of 1.3 × 105 gene copies (GC)/L. TetC was detected in 66.7% of samples, followed by sul1, sul2, and qnrA with the same detection frequency of 41.7%. Fifteen iARGs (including tetA, tetB, tetM, tetQ, tetX, sul1, sul2, sul3, ermB, blaTEM, and qnrA) were continuously detected in all collected tap water samples with sul1 and sul2 the most abundant. Additionally, both eARG and iARG concentrations in tap water presented a seasonal pattern with most abundant prevalence in summer. The concentration of observed intracellular sulfonamide resistance genes showed a significantly positive correlation with total nitrogen concentrations. This study suggested that eARG and iARG pollution of drinking water systems pose a potential risk to human public health.
The proper interactions between blood vessels and neurons are critical for maintaining the strength of neural circuits and cognitive function. However, the precise molecular events underlying these ...interactions remain largely unknown. Here, we report that the selective knockout of semaphorin 3G (Sema3G) in endothelial cells impaired hippocampal-dependent memory and reduced dendritic spine density in CA1 neurons in mice; these effects were reversed after restoration of Sema3G levels in the hippocampus by AAV transfection. We further show that Sema3G increased excitatory synapse density via neuropilin-2/PlexinA4 signaling and through activation of Rac1. These results provide the first evidence that, in the central nervous system, endothelial Sema3G serves as a vascular-derived synaptic organizer that regulates synaptic plasticity and hippocampal-dependent memory. Our findings highlight the role of vascular endothelial cells in regulating cognitive function through intercellular communication with neurons in the hippocampus.
Display omitted
•Endothelium-derived Sema3G is necessary for synaptic plasticity in the hippocampus•Loss of Sema3G in the vascular endothelium results in behavioral and memory deficits•Sema3G regulates synaptic structure and function via the neuropilin-2/PlexinA4 receptor•Sema3G functionally links the endothelium to signaling cascades activated in neurons
Tan et al. reveal a key mechanism that underlies signaling from endothelial cells to neurons in the brain. They identify that the endothelium-secreted protein semaphorin 3G (Sema3G) regulates synaptic structure and plasticity in hippocampal neurons through its neuronal neuropilin-2/PlexinA4 holoreceptor.
Adaption to adverse environments plays an important role in bacterial survival and is receiving increasing globe attention now. Here, cultivable chlorine-injured Pseudomonas aeruginosa, produced on ...the chlorination process, was investigated about their resistance to antibiotics. Then, global transcriptional analyses, quantitative PCR (qPCR) validation and antioxidant enzymes measurement were performed to explore the underlying mechanisms. The results showed that chlorine injury enhanced antibiotic resistance in P. aeruginosa and cultivable chlorine-injured P. aeruginosa exposed to 4 mg/L sodium hypochlorite (half of the lethal dose) improved antibiotic resistance against ceftazidime, chloramphenicol and ampicillin by 1.4–5.6 fold. This increase in antibiotic resistance was not hereditable and over expression of the MexEF-OprN efflux pump resulting from oxidative stress contributed to it. These results demonstrate temporal physiological persistence to antibiotics in cultivable chlorine-injured pathogens, suggesting their survival from adverse environments with antibiotic exposure and thereby posing lasting hazards to human health.
Display omitted
•Chlorine-injury increased antibiotic resistance in P. aeruginosa.•The mechanism of resistance was overexpression of MexEF-OprN.•This process may increase survival of pathogens in the water treatment system.
lKetamine functioned as a prophylactic agent against postpartum depression.lKetamine relieved suicidal ideation in women with postpartum depression.lThe antidepressant efficacy of ketamine was more ...obvious in some subgroups. (e.g., women with antenatal depressive symptom and antenatal suicidal ideation).
This study aimed to explore the effect of prophylactic ketamine administration on postpartum depression in Chinese woman undergoing cesarean section. This randomized controlled study included 654 Chinese women undergoing cesarean section. At 10 min after child birth, patients in the ketamine group were given 0.5 mg/kg ketamine, whereas patients in the control group received standard postpartum care. At the end of operation, all patients were armed with a patient-controlled intravenous analgesia device. The primary outcome was the prevalence of postpartum depression (PPD), as assessed by the Edinburgh Postnatal Depression Scale (EPDS), and the secondary outcomes included the safety assessment and the Numerical Rating Scale (NRS) of postoperative pain. The prevalence of postpartum blues and postpartum depression were significantly lower in the ketamine group than in the control group. Logistic analysis showed that ketamine administration protected against postpartum depression, and PPD-associated risk factors included stress during pregnancy, antenatal depressive symptom and antenatal suicidal ideation. In addition, the antidepressive effect of prophylactic ketamine was stronger in mothers with a history of moderate stress during pregnancy, antenatal depressive symptom and antenatal suicidal ideation. Our findings suggest that ketamine functions as a prophylactic agent against PPD.
Facile synthesis without involvement of toxic reagents is of great significance in the practical application of photovoltaic materials. In this work, four acceptor‐donor‐acceptor (A−D−A) type ...unfused‐ring acceptors (UFRAs) with stepwise extension in π‐conjugation, i. e., CPFB‐IC‐n (n=1–4), involving cyclopentadithiophene (CPDT) and 1,4‐difluorobenzene (DFB) as cores, are facilely synthesized by an atom‐, step‐economic and labor‐saving method through direct arylation of C−H bond (DACH). Among them, CPFB‐IC‐4 has the longest conjugation lengths among the molecular UFRA ever reported. The dependence of optoelectronic properties and photovoltaic performances of CPFB‐IC‐n (n=1–4) on conjugation length were systematically investigated. CPFB‐IC‐2 with near zero highest occupied molecular orbital (HOMO) offsets (ΔEHOMO=0.06 eV) achieves the highest power conversion efficiency (PCE), due to the significantly enhanced open voltage (VOC) and short current (JSC) caused by the balanced frontier molecular orbitals (FMOs) and complementary light absorption. Our work demonstrates that the optical properties and FMOs of UFRAs can be finely tuned by the stepwise elongation of conjugation lengths. Meanwhile, DACH coupling as a powerful tool here established will be a promising candidate for synthesizing high‐performance oligomeric UFRAs.
Tailor the π‐conjugation lengths: C−H direct arylation is successfully applied to synthesize unfused‐ring acceptors with different π‐conjugation lengths, CPFB‐IC‐n (n=1–4), with finely tuned optical properties and frontier molecular orbital (FMO) levels. CPFB‐IC‐2 with ΔEHOMO=0.06 eV achieves the highest power conversion efficiency (9.32 %), due to the improved VOC, JSC and FF because of the balanced FMOs and suitable phase separation.
Gene function studies benefit from the availability of mutants. In plants, Agrobacterium‐mediated genetic transformation is widely used to create mutants. These mutants, also called transformants, ...contain one or several transfer‐DNA (T‐DNA) copies in the host genome. Quantifying the copy number of T‐DNA in transformants is beneficial to assess the number of mutated genes. Here, we developed a competitive polymerase chain reaction (PCR)‐based method to detect a single copy of a T‐DNA insertion in transformants. The competitor line BHK−‐1 that contains a single copy of competitor BHK− (BHK, Basta, Hygromycin, Kanamycin‐resistant genes) was crossed with test transformants and the genomic DNA of F1 plants was subjected to competitive PCR. By analyzing the gray ratio between two PCR products, we were able to determine whether or not the test transformants contained a single copy of T‐DNA insertion. We also generated the control lines BHK±1:1 and BHK±2:1, which contain the target (BHK+) and competitor (BHK−) in a ratio of 1:1 and 2:1, respectively. The ratios of their PCR products are useful references for quantitative analysis. Overall, this method is reliable and simple in experimental manipulations and can be used as a substitute for Southern‐blot analysis to identify a single copy of T‐DNA insertion in transformants.
Blood-brain barrier (BBB) dysfunction has been suggested to play an important role in epilepsy. However, the mechanism mediating the transition from cerebrovascular damage to epilepsy remains ...unknown. Here, we report that endothelial cyclin-dependent kinase 5 (CDK5) is a central regulator of neuronal excitability. Endothelial-specific Cdk5 knockout led to spontaneous seizures in mice. Knockout mice showed increased endothelial chemokine (C-X-C motif) ligand 1 (Cxcl1) expression, decreased astrocytic glutamate reuptake through the glutamate transporter 1 (GLT1), and increased glutamate synaptic function. Ceftriaxone restored astrocytic GLT1 function and inhibited seizures in endothelial Cdk5-deficient mice, and these effects were also reversed after silencing Cxcl1 in endothelial cells and its receptor chemokine (C-X-C motif) receptor 2 (Cxcr2) in astrocytes, respectively, in the CA1 by AAV transfection. These results reveal a previously unknown link between cerebrovascular factors and epileptogenesis and provide a rationale for targeting endothelial signaling as a potential treatment for epilepsy.
PDF
