Recent progress of metal-organic framework-based nanozymes with oxidoreductase-like activity.

Nanozymes, a class of synthetic nanomaterials possessing enzymatic catalytic properties, exhibit distinct advantages such as exceptional stability and cost-effectiveness. Among them, metal-organic framework (MOF)-based nanozymes have garnered significant attention due to their large specific surface area, tunable pore size and uniform structure. MOFs are porous crystalline materials bridged by inorganic metal ions/clusters and organic ligands, which hold immense potential in the fields of catalysis, sensors and drug carriers. The combination of MOFs with diverse nanomaterials gives rise to various types of MOF-based nanozyme, encompassing original MOFs, MOF-based nanozymes with chemical modifications, MOF-based composites and MOF derivatives. It is worth mentioning that the metal ions and organic ligands in MOFs are perfectly suited for designing oxidoreductase-like nanozymes. In this review, we intend to provide an overview of recent trends and progress in MOF-based nanozymes with oxidoreductase-like activity. Furthermore, the current obstacles and prospective outlook of MOF-based nanozymes are proposed and briefly discussed. This comprehensive analysis aims to facilitate progress in the development of novel MOF-based nanozymes with oxidoreductase-like activity while serving as a valuable reference for scientists engaged in related disciplines.

Simultaneous binding characterization of different chromium speciation to serum albumin.

The binding process between three species of chromium and serum albumin (SA) was investigated, as well as the interaction between K2Cr2O7 and bovine serum albumin (BSA) under coexistence of different chromium forms. CrCl3, K2Cr2O7 and Crpic bound to SA spontaneously through Van der Waals force, and their binding constants were 103-104 M-1 at 298 K, respectively. K2Cr2O7 and Crpic both had strong binding affinity for BSA, and significantly affected the secondary structure of BSA and the microenvironment surrounding amino acid residues. Chromium exhibited a greater fluorescence quenching constant towards HSA than toward BSA, and K2Cr2O7 induced greater conformational changes in human serum albumin (HSA) than in BSA. A weak binding of CrCl3 to BSA had no significant effect on the binding affinity of K2Cr2O7 to BSA. K2Cr2O7 and BSA have a greater binding affinity when coexisting with Crpic, and K2Cr2O7 induces a greater conformational change in BSA.

Hematologic health services and practical characteristics: report of a nationwide survey among Chinese hematologists.

BACKGROUND: In the past 40 years, China has experienced tremendous economic development, but the current situation of hematologists has rarely been reported. A landscape survey of human resources is essential for healthcare development and policy formulation in the future. METHODS: The Chinese Society of Hematology initiated a survey of Chinese hematologists in mainland China for evaluating demographic and practice characteristics. Respondents were anonymous, and there were no limitations regarding their age, sex, etc. RESULTS: Totally 2032 hematologists responded, with a median age bracket of 36-45 years. Respondents were well engaged into subspecialties, and 28.1% acquired doctorates of philosophy. Hematopoietic cell transplantation (HCT) centers have been established all over China. Higher-GDP regions reported more advantages, including bigger scale of transplant centers (P < 0.001), younger age structure (P = 0.039), better education qualifications (P = 0.001) and less turnover intentions (P = 0.004), despite of increased risk of medical disputes (P = 0.028). Although females accounted for 65.5% of hematologists, males were older (P < 0.001), and had more senior professional titles (P < 0.001), academic positions (P < 0.001), opportunities for continuing education (P < 0.001), and paper publishing in the recent two years (P = 0.001). For turnover intention, the higher GDP regions led to an independently reduced risk (HR = 0.673, 95%CI [0.482-0.940], P = 0.020), whereas medical disputes resulted in an increased the risk (HR = 2.037, 95%CI [1.513-2.743], P < 0.001). Considering the impact of the COVID-19 pandemic, majority of respondents believed that the decline in patient visits and delay in treatment was within 30%. 67.9% of respondents reported a decrease of the use of bone marrow as grafts but 18.8% reported an increase of cord blood units. 35.0% of the respondents switched their daily work to support the anti-epidemic medical activities. CONCLUSIONS: We concluded the discipline of hematology in China has flourished in recent years with a young workforce, while regional economic and gender disparities warrant further continuous optimization. Joint efforts against the impact of COVID-19 are needed in the post-pandemic era.

Recent advances in colorimetric sensors based on nanozymes with peroxidase-like activity.

Nanozymes have been widely used to construct colorimetric sensors due to their advantages of cost-effectiveness, high stability, good biocompatibility, and ease of modification. The emergence of nanozymes greatly enhanced the detection sensitivity and stability of the colorimetric sensing platform. Recent significant research has focused on designing various sensors based on nanozymes with peroxidase-like activity for colorimetric analysis. However, with the deepening of research, nanozymes with peroxidase-like activity has also exposed some problems, such as weak affinity and low catalytic activity. In view of the above issues, existing investigations have shown that the catalytic properties of nanozymes can be improved by adding surface modification and changing the structure of nanomaterials. In this review, we summarize the recent trends and advances of colorimetric sensors based on several typical nanozymes with peroxidase-like activities, including noble metals, metal oxides, metal sulfides/metal selenides, and carbon and metal-organic frameworks (MOF). Finally, the current challenges and prospects of colorimetric sensors based on nanozymes with peroxidase-like activity are summarized and discussed to provide a reference for researchers in related fields.

Concordance in pathogen identification at the upper and lower respiratory tract of children with severe pneumonia.

BACKGROUND: Nasopharyngeal swabs are taken to determine the causative agent of community acquired pneumonia (CAP), while the reliability of upper respiratory tract sampling as a proxy for lower respiratory tract infections is still unclear. METHODS: Nasopharyngeal (NP) swabs, bronchoalveolar lavage (BAL) fluid samples and clinical data were collected from 153 hospitalized children between 3 months and 14 years of age with severe CAP, enrolled from March to June 2019. Written informed consent for the storage and use of the samples for further studies was obtained from the parents or caregivers. Putative pathogens were detected using a sensitive, high-throughput GeXP-based multiplex PCR and qPCR. RESULTS: The same bacterial species in paired samples were found in 29 (23.4%) and the same viral species in 52 (27.5%) of the patients. moderate concordance was found for Mycoplasma pneumoniae (ĸ=0.64), followed by Haemophilus influenzae (ĸ=0.42). The strongest discordance was observed for human adenovirus and also for Pseudomonas aeruginosa, the latter was exclusively detected in BAL samples. In the adenovirus cases strong concordance was associated with high viral loads in the NP swabs. CONCLUSION: The variation in concordance in pathogen detection in the upper and lower respiratory tract of children with severe pneumonia is generally high but varies depending on the species. Novel and impactful insights are the concordance between NP and BAL detection for M. pneumoniae and H. influenzae and the strong correlation between high adenoviral loads in NP swabs and detection in BAL fluid.

Response of the water footprint of maize production to high temperatures in the Huang-Huai-Hai region of China.

BACKGROUND: Water footprint (WF) can comprehensively evaluate agricultural water use efficiency under high-temperature weather. Based on the historical meteorological data in the Huang-Huai-Hai (3H) region of China, this study used the percentile threshold method to analyze the distribution of high-temperature events and set three types of meteorological scenarios, namely the actual temperature scenario (S1), the high temperatures in the ear stage scenario (S2), and the high temperatures in the flowering-maturity stage scenario (S3). The growing degree day (GDD) mode and calendar day (CD) mode in the AquaCrop model were used to simulate the yield per unit area (Yunit ) of maize under different temperature scenarios and then the crop evapotranspiration (ETc ) and production WF during maize growth period were calculated. RESULTS: The occurrence frequency of extreme high-temperature event in ear stage in the 3H region was lower than that in the flowering-maturity stage. There were significant differences in the WF of maize between S1 and S2 and between S1 and S3 in GDD mode, and significant differences in Yunit , ETc , and WF of maize under three temperature scenarios in the CD mode. CONCLUSION: High temperature events occur in maize growth period, especially in the flowering-maturity stage, will increase the WF of maize. Measures such as changing the planting structure, changing the sowing date of maize and cultivating heat-resistant maize varieties could be taken to reduce the negative impacts of high-temperature weather. © 2022 Society of Chemical Industry.

Interaction mechanism of benzophenone-type UV filters on bovine serum albumin: Insights from structure-affinity relationship.

Benzophenone (BP)-type UV filters can cause structural changes of carrier protein in plasma. The binding process of five BP-type UV filters with bovine serum albumin (BSA) was investigated by multiple characterization methods, along with their structure-affinity relationship involving the structure of the five BP-type UV filters and their binding affinity for BSA. The BP-type UV filters investigated bound to BSA spontaneously, and altered conformation of BSA. The binding constants and number of binding sites between BP-type UV filters and BSA were 103-106 M-1 and 0.82-1.26, respectively. These BP-type UV filters and BSA interacted with the same binding forces and went through the similar binding process, suggesting that the benzophenone skeleton structure was primarily responsible for the BP-type UV filters and BSA binding, and changes in the structure of the BSA. The BP-type UV filters with hydroxyl substituent (BP-1 and BP-9) and non-polar molecules (BP-6) had a high affinity for binding BSA and had a greater impact on BSA conformation.

A small molecule compound IX inhibits telomere and attenuates oncogenesis of drug-resistant leukemia cells.

Drug resistance is a common obstacle in leukemia treatment and failing to eradicate leukemia stem cells is the main cause of leukemia relapse. Previous studies have demonstrated that telomerase activity is associated with deregulated self-renewal of leukemia stem cells (LSCs). Here, we identified a novel compound IX, an imatinib derivative with a replacement fragment of a telomerase inhibitor, which can effectively eradicate LSCs but had no influence on normal hematopoietic stem cells (HSCs) survival. We showed that compound IX can decrease the viability of drug-resistant K562/G cells and blast crisis CML primary patient cells. Besides, IX can affect LSC survival, inhibit the colony-forming ability, and reduce LSC frequency. In vivo results showed that IX can relieve the tumor burden in patient-derived xenograft (PDX) model and prolong the lifespan. We observed that compound IX can not only decrease telomerase activity, but also affect the alternative lengthening of telomeres. In addition, IX can inhibit both the canonical and non-canonical Wnt pathways. Our data suggested this novel compound IX as a promising candidate for drug-resistant leukemia therapy.

Broad range detection of viral and bacterial pathogens in bronchoalveolar lavage fluid of children to identify the cause of lower respiratory tract infections.

BACKGROUND: Knowledge on the etiology of LRTIs is essential for improvement of the clinical diagnosis and accurate treatment. Molecular detection methods were applied to identify a broad range of bacterial and viral pathogens in a large set of bronchial alveolar lavage (BAL) fluid samples. The patterns of detected pathogens were correlated to the clinical symptoms. METHODS: BAL fluid samples and clinical data were collected from 573 hospitalized children between 1 month and 14 years of age with LRTIs, enrolled from January to December 2018. Pathogens were detected using standardized clinical diagnostics, with a sensitive, high-throughput GeXP-based multiplex PCR and with multiplex qPCR. Data were analyzed to describe the correlation between the severity of respiratory tract disease and the pathogens identified. RESULTS: The pathogen detection rate with GeXP-based PCR and multiplex qPCR was significantly higher than by clinical routine diagnostics (76.09% VS 36.13%,χ2 = 8.191, P = 0.004). The most frequently detected pathogens in the BAL fluid were human adenovirus (HADV)(21.82%), Mycoplasma pneumoniae (20.24%), human rhinovirus (13.96%), Streptococcus pneumoniae (8.90%) and Haemophilus influenzae (8.90%). In 16.4% of the cases co-detection with two or three different pathogens was found. Viral detection rates declined with age, while atypical pathogen detection rates increased with age. Oxygen supply in the HADV and Influenza H1N1 infected patients was more frequent (49.43%) than in patients infected with other pathogens. CONCLUSION: Broad range detection of viral and bacterial pathogens using molecular methods is a promising and implementable approach to improve clinical diagnosis and accurate treatment of LRTI in children.

Difference in the binding mechanism of distinct antimony forms in bovine serum albumin.

The toxicity of antimony (Sb) is closely related to its chemical forms. To further realize the toxicity risk of different forms of Sb, the separate and simultaneous binding mechanisms of antimony potassium tartrate/potassium pyroantimonate with bovine serum albumin (BSA) were investigated with muti-spectroscopic methods. Fluorescence quenching result and UV-vis absorption spectra showed that a 1:1 complex was formed between antimony potassium tartrate/potassium pyroantimonate and BSA through a modest binding force. The results revealed that the binding of antimony potassium tartrate/potassium pyroantimonate to BSA caused changes in the secondary structure of BSA. Both Sb forms (antimony potassium tartrate and potassium pyroantimonate) were able to interact with BSA when coexisting but there was a binding influence on their interacting with the BSA. Both Sb forms interfere with the binding of the other to protein.