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1.
J Am Chem Soc ; 2022 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-35535855

RESUMO

The optical manipulation of polarization has gained widespread attention because it offers a promising route to new contactless memories and switches. However, the current research basically focuses on the photocontrol of data storage rather than data reading, which cannot realize the whole process of contactless write-read-erase data storage. Here, we present a pair of enantiomorphic diarylethene derivative ferroelectric crystals, showing a light-driven phase transition triggered by photoisomerization between the open and closed forms. Under the visible light, they exhibit a binary-domain state in the open form with white color and the band gap of 3.26 eV, while they show a single-domain state in the closed form with blue color and the band gap of 1.68 eV after UV irradiation of 254/365 nm. In addition to writing and erasing ferroelectric domains with light, we can also use light to read their color to determine the polarization state of domains. Moreover, diarylethene derivatives have better thermal stability, higher photoexcited conversion efficiency, and larger changes of the absorption wavelength between two isomers than those in salicylideneaniline derivatives. This work not only discovers the first diarylethene-based ferroelectric crystals but also successfully realizes completely contactless manipulation of write-read-erase data storage in the organic ferroelectric semiconductors.

2.
Front Plant Sci ; 13: 881456, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35574123

RESUMO

In plants, the leaf is an essential photosynthetic organ, and is the primary harvest in forage crops such as alfalfa (Medicago sativa). Premature leaf senescence caused by environmental stress can result in significant yield loss and quality reduction. Therefore, the stay-green trait is important for improving the economic value of forage crops. Alkaline stress can severely damage leaf cells and, consequently, cause leaf senescence. To understand the molecular regulatory mechanisms and identify vital senescence-associated genes under alkaline stress, we used high-throughput sequencing to study transcriptional changes in Medicago truncatula, a model plant for forage crops. We identified 2,165 differentially expressed genes, 985 of which were identical to those in the dark-induced leaf senescence group. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses showed that the 985 genes were mainly enriched in nutrient cycling processes such as cellular amino acid metabolic processes and organic substance catabolic processes, indicating nutrient redistribution. The other 1,180 differentially expressed genes were significantly enriched in the oxidoreductase complex, aerobic respiration, and ion transport. Our analysis showed the two gene sets guiding the coupled physiological and biochemical alterations play different roles under alkaline stress with a coordinated and integrated way. Many transcription factor families were identified from these differentially expressed genes, including MYB, WRKY, bHLH, and NAC which have particular preference involved in stress resistance and regulation of senescence. Our results contribute to the exploration of the molecular regulatory mechanisms of leaf senescence in M. truncatula under alkaline stress and provide new candidate genes for future breeding to improve the biomass and quality of forage crops.

3.
Environ Technol ; : 1-46, 2022 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-35574708

RESUMO

Autotrophic nitrifying granular sludge (ANGS) was cultivated for the simultaneous removal of ammonia nitrogen and Tl(I) from inorganic wastewater. The chemical oxygen demand (COD) in the influent gradually decreased to approximately zero in four parallel sequencing batch reactors (B1: blank controller, B2: 10 mL of added nitrifying bacteria concentrate in each cycle, B3: 1 mg/L Tl(I) added in each cycle and B4: 10 mL of added nitrifying bacteria concentrate and 1 mg/L Tl(I) in each cycle) within 15 days. The main properties, such as the granulation rate and specific oxygen uptake rate (SOUR) of the ANGS in B1, B2, B3 and B4 tended to be stable within 40, 33, 30 and 33 days, the removal efficiencies of Tl(I) were 59.5%-82.9% and 57.1%-88.6% in B3 and B4 after Day 30, the removal efficiencies of ammonia nitrogen in B1, B2, B3 and B4 were usually above 90% after Day 33, and the total inorganic nitrogen (TIN) in the effluent of B1, B2, B3 and B4 gradually stabilized after Day 36, 32, 32 and 36, indicating that mature ANGS was successfully cultivated in B1, B2, B3 and B4 within 40, 33, 33 and 36 days. The nitrogen degradation kinetic parameters of ANGS indicated that B3 had the strongest ability to remove ammonia and nitrite, suggesting that Tl(I) stress was beneficial to ammonia nitrogen removal and nitrite oxidation. The adsorption of Tl(I) can be described by the Freundlich equation, and the addition of external nitrifying bacteria improved the adsorption ability of ANGS.

4.
Nat Commun ; 13(1): 2379, 2022 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-35501335

RESUMO

Shape memory alloys have been used extensively in actuators, couplings, medical guide wires, and smart devices, because of their unique shape memory effect and superelasticity triggered by the reversible martensitic phase transformations. For ferroic materials, however, almost no memory effects have been found for their ferroic domains after reversible phase transformations. Here, we present a pair of single-component organic enantiomorphic ferroelectric/ferroelastic crystals, (R)- and (S)-N-3,5-di-tert-butylsalicylidene-1-(1-naphthyl)ethylamine SA-NPh-(R) and SA-NPh-(S). It is notable that not only can their ferroic domain patterns disappear and reappear during reversible thermodynamic phase transformations, but they can also disappear and reappear during reversible light-driven phase transformations induced by enol-keto photoisomerization, both of which are from P1 to P21 polar space groups. Most importantly, the domain patterns are exactly the same in the initial and final states, demonstrating the existence of a memory effect for the ferroic domains in SA-NPh-(R) and SA-NPh-(S). As far as we are aware, the domain memory effect triggered by both thermodynamic and light-driven ferroelectric/ferroelastic phase transformations remains unexplored in ferroic materials. Thermal and optical control of domain memory effect would open up a fresh research field for smart ferroic materials.

5.
Front Neurosci ; 16: 850193, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35527820

RESUMO

In response to external threatening signals, animals evolve a series of defensive behaviors that depend on heightened arousal. It is believed that arousal and defensive behaviors are coordinately regulated by specific neurocircuits in the central nervous system. The ventral tegmental area (VTA) is a key structure located in the ventral midbrain of mice. The activity of VTA glutamatergic neurons has recently been shown to be closely related to sleep-wake behavior. However, the specific role of VTA glutamatergic neurons in sleep-wake regulation, associated physiological functions, and underlying neural circuits remain unclear. In the current study, using an optogenetic approach and synchronous polysomnographic recording, we demonstrated that selective activation of VTA glutamatergic neurons induced immediate transition from sleep to wakefulness and obviously increased the amount of wakefulness in mice. Furthermore, optogenetic activation of VTA glutamatergic neurons induced multiple defensive behaviors, including burrowing, fleeing, avoidance and hiding. Finally, viral-mediated anterograde activation revealed that projections from the VTA to the central nucleus of the amygdala (CeA) mediated the wake- and defense-promoting effects of VTA glutamatergic neurons. Collectively, our results illustrate that the glutamatergic VTA is a key neural substrate regulating wakefulness and defensive behaviors that controls these behaviors through its projection into the CeA. We further discuss the possibility that the glutamatergic VTA-CeA pathway may be involved in psychiatric diseases featuring with excessive defense.

6.
Artigo em Inglês | MEDLINE | ID: mdl-35579163

RESUMO

BACKGROUND: Glanders is a rare zoonotic disease caused by Burkholderia mallei. Humans can be infected by B. mallei, which causes cutaneous lymphadenitis and pneumonia, leading to sepsis and death in severe cases. CASE PRESENTATION: We report a case of a 60-year-old male who was diagnosed with glanders. The patient who had a history of diabetes presented with cough, expectoration, and fever. Computed tomography (CT) imaging showed B. mallei infection in the right upper lobe of the lung with mediastinal lymph node involvement and the lingual segment of the left lung. Moreover, the posterior basal segment of the lower lobe of both lungs had inflammation. Subsequently, B. mallei infection was confirmed by lymph node biopsy and bronchoalveolar lavage multiplex PCR-based targeted gene sequencing. After meropenem treatment, the patient was discharged, and CT imaging showed reduced absorption of pulmonary inflammatory lesions. CONCLUSIONS: Glanders is a rare disease that can cause skin infection, lymphadenitis, and pneumonia and in severe cases, it can be life-threatening. The diagnosis of this disease mainly relies on microbiological culture and pathological biopsy. Diagnosis is also facilitated by multiplex PCR-based targeted gene sequencing facilitates the diagnosis of this disease. Glanders is treated with cephalosporins, carbapenems, and other sensitive antibiotics.

7.
Front Mol Neurosci ; 15: 822088, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35600074

RESUMO

Cell pyroptosis is one of the main forms of neuronal injury after cerebral ischemia-reperfusion. It is accompanied by an inflammatory reaction and regulated by the caspase gene family. Electroacupuncture (EA) can reduce neuronal injury caused by cerebral ischemia-reperfusion, and we speculated that EA can prevent neuronal pyroptosis after cerebral ischemia-reperfusion by regulating the nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3)/caspase-1 pathway. The cerebral ischemia-reperfusion injury model of C57 and caspase-1 gene knockout (Cas-1 ko) mice was established by Longa's method. EA was conducted at acupoints Chize (LU5), Hegu (LI4), Sanyinjiao (SP6), and Zusanli (ST36) for 1.5 h after cerebral ischemia-reperfusion injury for 20 min, and observation was carried out after 24 h. Neurological deficit scores evaluated the neurological function, cerebral infarction volume was observed by triphenyl tetrazolium chloride (TTC) staining, hematoxylin and eosin (H&E) staining, TUNEL and caspase-1 double-labeled fluorescence staining, and NLRP3 and caspase-1 double-labeled immunofluorescence staining that were used to observe the morphology of neurons in hippocampus, and the protein expression of NLRP3, pro-caspase-1, cleaved caspase-1 p20, pro-interleukin-1ß (IL-1ß), cleaved IL-1ß, and GSDMD was detected by Western blot assay. Results showed that EA could reduce the score of neurological deficit, reduce the volume of cerebral infarction and improve the degree of nerve cell injury, and inhibit NLRP3, pro-caspase-1, cleaved caspase-1 p20, pro-IL-1ß, cleaved IL-1ß, and GSDMD protein expression. In summary, EA plays a neuroprotective role by reducing the pyroptotic neurons that were caspase 1-mediated and inflammatory response after cerebral ischemia-reperfusion.

8.
J Colloid Interface Sci ; 622: 481-493, 2022 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-35525149

RESUMO

Inflenza A viruses (IAVs) are highly transmissible and pathogenic Orthomyxoviruses, which have led to worldwide outbreaks and seasonal pandemics of acute respiratory diseases, causing serious threats to public health. Currently used anti-influenza drugs may cause neurological side effects, and they are increasingly less effective against mutant strains. To help prevent the spread of IAVs, in this work, we have developed quercetin-derived carbonized nanogels (CNGsQur) that display potent viral inhibitory, antioxidative, and anti-inflammatory activities. The antiviral CNGsQur were synthesized by mild carbonization of quercetin (Qur), which successfully preserved their antioxidative and anti-inflammatory properties while also contributed enhanced properties, such as water solubility, viral binding, and biocompatibility. Antiviral assays of co-treatment, pre-treatment, and post-treatment indicate that CNGsQur interacts with the virion, revealing that the major antiviral mechanism resulting in the inhibition of the virus is by their attachment on the cell surface. Among them, the selectivity index (SI) of CNGsQur270 (>857.1) clearly indicated its great potential for clinical application in IAVs inhibition, which was much higher than that of pristine quercetin (63.7) and other clinical drugs (4-81). Compared with quercetin at the same dose, the combined effects of viral inhibition, antioxidative and anti-inflammatory activities impart the superior therapeutic effects of CNGsQur270 aerosol inhalation in the treatment of IAVs infection, as evidenced by a mouse model. These CNGsQur effectively prevent the spread of IAVs and suppress virus-induced inflammation while also exhibiting good in vivo biocompatibility. CNGsQur shows much promise as a clinical therapeutic agent against infection by IVAs.

9.
Environ Technol ; : 1-15, 2022 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-35439111

RESUMO

The performance of endogenous/exogenous nitrification and denitrification in an aerobic granular sequencing batch reactor was investigated for treating inorganic wastewater with ammonia nitrogen of 250 mg/L. The sequencing batch reactor with an effective volume of 120.5 L was started by seeding autotrophic nitrifying granular sludge (ANGS) and operated under oxic (110 min)/anoxic (120 min)/oxic (110 min) aeration mode. The total inorganic nitrogen (TIN) removal efficiency of ANGS was between 60% and 70% without external carbon sources in days 1-25. However, the operation mode was unsustainable as endogenous nitrification and denitrification would lead to an obvious decrease of sludge concentration. After sodium acetate (the contributed chemical oxygen demand in the reactor was 250-300 mg/L) was added at the beginning of the anaerobic/anoxic stage from day 26, aerobic granules were inadaptable in a few days, which resulted in particle disintegration and SVI increase. As microbes gradually acclimated to the new environment, the aerobic granular sludge became smoother and denser, the relative abundance of denitrifying bacteria increased to 66.07%, and the removal efficiency of TIN gradually increased to more than 90% from day 89. Contributions of endogenous/exogenous nitrification and denitrification to TIN removal were 54.09% and 46.01%, respectively. The coupling of endogenous/exogenous nitrification and denitrification could reduce the aeration consumption, save the external carbon source dosage and decrease the alkalinity consumption, which provided another option for treating wastewater from ionic rare earth mine.

10.
Stem Cells Dev ; 2022 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-35481777

RESUMO

Neuroinflammation is one of the typical events in multiple neurodegenerative diseases, whereas microglia are the critical participants in the pathogenesis of neuroinflammation. Several studies suggest that neural stem cells (NSCs) present immunomodulatory benefits due to their paracrine products, which contain mounting trophic factors. In the current study, the anti-inflammatory effects of neural stem cells secretome (NSC-S) on lipopolysaccharide (LPS)-induced neuroinflammatory models were evaluated in vivo and the underlying mechanism was further investigated in vitro. It was revealed that NSC-S significantly attenuated the severity of LPS-induced behaviour disorders and inflammatory response in mice. In vitro studies found that NSC-S significantly promoted the polarization of microglia from proinflammatory M1 to anti-inflammatory M2 phenotype, and reduced the production of proinflammatory cytokines while elevated anti-inflammatory cytokines in BV2 cells. NSC-S promoted peroxisome proliferator-activated receptor gamma (PPAR-γ) pathway activation. However, these effects of NSC-S were abrogated by PPAR-γ inhibitor GW9662. Notably, the fatty acid binding protein 5 (FABP5) in NSC-S may mediate PPAR-γ activation and inflammation remission. In summary, NSC-S promotes the regression of LPS-induced microglia-mediated inflammation through the PPAR-γ pathway. This function might be achieved via FABP5.

11.
Artigo em Inglês | MEDLINE | ID: mdl-35451698

RESUMO

Noninvasive examination is an emerging area in the field of neuro-oncology. Liquid biopsy captures the landscape of genomic alterations of brain tumors and revolutionizes the traditional diagnosis approaches. Rapidly changing sequencing technologies and more affordable prices put the screws on more application of liquid biopsy in clinical settings. In the past few years, extensive application of liquid biopsy has been seen throughout the whole diagnosis and treatment process of brain tumors, including early and accurate detection, characterization and dynamic monitoring. Here, we summarized and compared the most advanced techniques and target molecules or macrostructures related to brain tumor liquid biopsy. We further reviewed and emphasized recent progression in different clinical settings for brain tumors in blood and CSF. The preferred protocol, potential novel biomarkers and future development are discussed in the last part.

13.
Artigo em Inglês | MEDLINE | ID: mdl-35457748

RESUMO

Hospital service area (HSA) and Hospital referral region (HRR) are significant in organizing maternal care resources in hierarchical medical systems. This quantitative study aims to delineate HAS and HRR by using obstetrics medical record data reflecting patients' medical behavior to improve the efficiency of the utilization of medical resources. The Dartmouth method and an improved version that considers the administrative division was applied to delineate HSA and HRR by using the obstetrics medical records in Hubei Province of China in 2016. The result shows that 117 Dartmouth HSAs have a strong correlation with the county boundaries and 22 Dartmouth HRRs are highly coincident with the prefecture boundaries in Hubei. In addition, 25 improved Dartmouth HRRs within prefecture boundaries and core areas serving patients across prefecture boundaries have been identified. Based on the above results, two sets of hierarchical healthcare systems were constructed, respectively, which can provide methods and references for delineating HAS and HRR in the hierarchical medical systems in other regions of China and developing countries. The findings of this study shed light on future research and policymaking in the spatial organization of medical resources for improving the efficiency and equity in maternal care delivery.


Assuntos
Atenção à Saúde , Encaminhamento e Consulta , China , Família , Serviços de Saúde , Humanos
14.
J Plant Physiol ; 273: 153691, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35483247

RESUMO

Vascular connection is key to successful graft. Little study has been devoted to the behavior of tracheary elements (TEs), the basic component of vascular bundles, during vascular connection between scion and rootstock. Here we report the structural changes of TEs at the graft interface between two quinoa cultivars, Qaidam White-1 (QW1) and Qaidam Red-1 (QR1). Our results showed that TEs in ungrafted plants developed following an ontogenetic sequence, i.e., the annular vessel, helical vessel, scalariform vessel, reticulate vessel, and pitted vessel. However, this process was greatly accelerated in grafted plants, resulting in quick developmental transition of TE wall patterning. At the early stage of intraspecific grafting (e.g., 5 days after grafting), the membrane-like cellular patches were heavily accumulated at the graft interface but quickly retreated within 2-4 days, suggesting an early emergency response to grafting. The TE length in both scion and rootstock was significantly shorter (more than 50% on average, nTE = 747) than the ungrafted plants in the same period. These short TEs were gradually integrated into a long, continuous conduit, thereby enabling the functional vasculature at the graft union. In addition, the pit size was gradually reduced, for example, for the surface area of outer pit aperture, from 12.73 ± 3.15 to 5.40 ± 0.30 µm2, or for the surface area of inner pit aperture, from 9.34 ± 3.33 to 1.96 ± 1.04 µm2, in 18 days (npits = 2830). Taken together, the morphological changes of TEs and cellular responses to grafting in the intraspecific grafts seemed to be conservative to other homografts and heterografts, implying that these behavioral changes are highly adaptive to the scion-rootstock interaction.


Assuntos
Chenopodium quinoa , Plantas
15.
Neurosci Lett ; 778: 136603, 2022 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-35364125

RESUMO

During neurodevelopment, differentiation of neural stem/progenitor cells (NSPCs) into neurons are regulated by many factors including Notch signaling pathway. Herein, we report the effect of a Notch signaling blocker, i.e. γ -secretase inhibitor (GSI), on this differentiating process, especially on the morphological development. NSPCs were cultured and induced to differentiate with or without GSI. The neurite outgrowth was impeded by GSI application and the expression of a Notch signaling downstream effector miR-342-5p increased with the downregulated expression of Notch effectors Hes1 and Hes5. Upregulated expression of miR-342-5p in differentiating NSPCs could shorten the neurite length of progeny neurons, which was similar to the effect of GSI. To avoid the possible influence from astrocytes into neurons, we directly applied cultured neurons, on which GSI could shorten the processes and RBP-J knockdown could also reduce the neurite length. Similarly, transfection of miR-342-5p mimics or inhibitors into PC12 cells led to shorter or longer processes of cells compared with control ones. Furthermore, in differentiating NSPCs, GSI-induced shorter neurites could be partially rescued by miR-342-5p inhibitors, and STAT3 was one of the possible targets of miR-342-5p during this differentiating process as indicated by results of Western Blot test, luciferase reporter assay and GFP reporter assay. To further demonstrate the role of STAT3, it was introduced into GSI-treated neurons and the GSI-affected neurites could also be partially rescued. In conclusion, GSI could influence the morphological development of neurons and the possible mechanism involved Notch/miR-342-5p and STAT3. These results would be informative for future therapeutic research.


Assuntos
MicroRNAs , Células-Tronco Neurais , Receptores Notch , Secretases da Proteína Precursora do Amiloide/metabolismo , Animais , MicroRNAs/metabolismo , Células-Tronco Neurais/metabolismo , Neurônios/metabolismo , Ratos , Receptores Notch/metabolismo , Transdução de Sinais
16.
Cell Transplant ; 31: 9636897221079336, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35416722

RESUMO

Hypoxic injury to the brain is very intricate under the control of biochemical reactions induced by various factors and mechanisms. Long non-coding RNAs (lncRNAs) have already been revealed to affect pathological processes in the nervous system of different degrees. This research aimed to investigate the mechanisms implicated in hypoxic brain injury. ß-Asarone mitigated the decrease of cell viability, superoxide dismutase activity, and mitochondrial membrane potential, as well as the increase of cell apoptosis, lactate dehydrogenase release, malondialdehyde content, and reactive oxidative species production by cobalt chloride. LncRNA ribonuclease P RNA component H1 (RPPH1) was discovered to be highly expressed in hypoxia-induced PC12 cells, and ß-Asarone addition led to a decline in RPPH1 expression. RPPH1 overexpression reversed the effect of ß-Asarone on hypoxia-induced injury in PC12 cells. Furthermore, we proved that RPPH1 could sponge miR-542-3p. Subsequently, death effector domain containing 2 (DEDD2) was proven as the downstream gene of RPPH1/miR-542-3p axis. Eventually, the whole regulation mechanism of RPPH1/miR-542-3p/DEDD2 axis was testified through rescue assays. The impacts of ß-Asarone on hypoxia-induced PC12 cells could be countervailed by RPPH1 augment, which was also discovered to be neutralized in response to miR-542-3p overexpression or DEDD2 depletion. These findings offered a novel perspective for understanding neuroprotection.


Assuntos
MicroRNAs , RNA Longo não Codificante , Derivados de Alilbenzenos , Animais , Anisóis , Apoptose , Hipóxia , MicroRNAs/metabolismo , Células PC12 , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismo , Ratos
18.
Cancer Gene Ther ; 2022 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-35388172

RESUMO

Increased vascular permeability facilitates metastasis. Cancer-secreted exosomes are emerging mediators of cancer-host crosstalk. Epstein-Barr virus (EBV), identified as the first human tumor-associated virus, plays a crucial role in metastatic tumors, especially in nasopharyngeal carcinoma (NPC). To date, whether and how exosomes from EBV-infected NPC cells affect vascular permeability remains unclear. Here, we show that exosomes from EBV-positive NPC cells, but not exosomes from EBV-negative NPC cells, destroy endothelial cell tight junction (TJ) proteins, which are natural barriers against metastasis, and promote endothelial-to-mesenchymal transition (EndMT) in endothelial cells. Proteomic analysis revealed that the level of HMGA2 protein was higher in exosomes derived from EBV-positive NPC cells compared with that in exosomes derived from EBV-negative NPC cells. Depletion of HMGA2 in exosomes derived from EBV-positive NPC cells attenuates endothelial cell dysfunction and tumor cell metastasis. In contrast, exosomes from HMGA2 overexpressing EBV-negative NPC cells promoted these processes. Furthermore, we showed that HMGA2 upregulates the expression of Snail, which contributes to TJ proteins reduction and EndMT in endothelial cells. Moreover, the level of HMGA2 in circulating exosomes is significantly higher in NPC patients with metastasis than in those without metastasis and healthy negative controls, and the level of HMGA2 in tumor cells is associated with TJ and EndMT protein expression in endothelial cells. Collectively, our findings suggest exosomal HMGA2 from EBV-positive NPC cells promotes tumor metastasis by targeting multiple endothelial TJ and promoting EndMT, which highlights secreted HMGA2 as a potential therapeutic target and a predictive marker for NPC metastasis.

19.
Artigo em Inglês | MEDLINE | ID: mdl-35445265

RESUMO

OBJECTIVES: To characterize a clinical Klebsiella pneumoniae isolate from China co-harbouring tet(X4), blaOXA-181 and the aerobactin operon on an IncFIBk-FII-X3-ColKP3 hybrid plasmid. METHODS: A tigecycline-resistant strain was recovered from the intestinal sample of a patient. It was subjected to antimicrobial susceptibility testing, conjugation assay, virulence testing, WGS, bioinformatics analysis, plasmid stability testing and fitness cost testing. RESULTS: The strain K. pneumoniae T877 was resistant to tigecycline, intermediate to piperacillin/tazobactam and ertapenem, and positive for tet(X), blaOXA-181 and the virulence-associated operon iutAiucABCD, which were located on the same plasmid, named pKPT877-hybrid. It was 99.96% identical to the IncFIBk-FII plasmid pSCH6109-Vir (accession number CP050860) from K. pneumoniae strain SCH6109 at 96% coverage with the absence of a 50 kb region on pKPT877-hybrid; this region was highly homologous to the 51 kb IncX3-ColKP3-type, blaOXA-181-carrying plasmid pOXA181-191773 (accession number CP080367). Plasmid pKPT877-hybrid was conjugatively transferable to the ST11 K. pneumoniae strains FJ8 and KP04. pKPT877-hybrid did not have a significant impact on the fitness cost and could be maintained stably in T877. CONCLUSIONS: We report for the first time (to the best of our knowledge) the co-transfer of last-line antibiotic resistance determinants [tet(X4) and blaOXA-181] and the aerobactin operon (iutAiucABCD) by a mobile IncFIBk-FII-X3-ColKP3 hybrid plasmid, which can be stably maintained in K. pneumoniae strains, even in the absence of antibiotic selective pressure. Once the plasmid transfers to a K. pneumoniae with porin deficiency, the strain might have high levels of resistance to carbapenems and tigecycline, which are the last line of defence against infections. Heightened and continuous efforts are needed to control its dissemination.

20.
J Infect Public Health ; 15(5): 558-561, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35452898

RESUMO

Antimicrobial resistance is a quintessential One Health issue, among the most serious 21st century global threats in human and veterinary medicine. Wild animals are usually not directly exposed to clinically relevant antibiotics; however, antibacterial resistance in wild animals has been increasingly reported worldwide in parallel to the situation in human and veterinary medicine. In this work, we collected 100 fecal samples from the crested ibis protected areas. A total of eight Escherichia coli (E. coli) isolates positive for mcr-1 were obtained, and all of them were analyzed using WGS (whole genome sequencing). The WGS analysis showed that the isolates were assigned to four different sequence types (ST) overall. The antibiotic susceptibility profile showed that of eight E. coli isolates, six strains exhibited resistance to tetracycline and all mcr-1-positive E. coli (MCREC) strains showed resistance to colistin. Our findings importantly document the epidemic spread of MCREC in crested ibis in China.


Assuntos
Farmacorresistência Bacteriana , Infecções por Escherichia coli , Proteínas de Escherichia coli , Escherichia coli , Animais , Antibacterianos/farmacologia , Aves/microbiologia , Colistina/farmacologia , Farmacorresistência Bacteriana/genética , Escherichia coli/genética , Infecções por Escherichia coli/microbiologia , Infecções por Escherichia coli/veterinária , Proteínas de Escherichia coli/genética , Testes de Sensibilidade Microbiana , Plasmídeos/genética
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