A green microwave method using glycine and urea as precursors was developed to synthesize carbon dots (CDs). The CDs can be used as an effective fluorescence probe with high selectivity and sensitivity for the detection of morin based on the fluorescence quenching of CDs.

Purpose In this study, we analyzed the clinical distribution and drug resistance of carbapenem-resistant Klebsiella pneumoniae (CRKP) strains, the minimum inhibitory concentrations (MIC), MIC50 and MIC90, and geographical distribution in Hebei Province, China. We aimed to provide epidemiological research data, formulate appropriate combined treatment schemes, reasonably select antibiotics, and standardize nosocomial infection control schemes. Patients and Methods A total of 6328 strains of CRKP were collected from 2017 to 2019. The MIC was determined for the drug sensitivity test, and the experimental data were statistically analyzed using WHONET5.6. Results The detection rate of CRKP increased annually from 13.4% in 2017 to 14.5% in 2018, and 14.6% in 2019. The ratio of males to females was approximately 2:1; 53.6% were elderly, 39% were adults, 4.8% were minors, and 2.5% were newborns. The specimens collected were mainly sputum (70.9%). The resistance rate of CRKP to carbapenems and other β-lactam antibiotics was found to be increasing, with resistance rates generally greater than 90%. The resistance rate to aminoglycoside antibiotics decreased yearly to approximately 50%, and the resistance rate to quinolones remained unchanged at approximately 80%. From 2017 to 2019, the resistance rate of CRKP in Hebei Province to various antibiotics was high, and the resistance rate to β-lactam antibiotics increased each year. Conclusion The situation of CRKP resistance is severe in Hebei Province, China. The resistance rate to most antibiotics is very high and shows an upward trend. Among them, the resistance rate to polymyxin is low; however, few resistant strains do exist. MIC50 and MIC90 are higher than their MICs. It mainly causes lung infection in elderly men. This study is helpful to improve the diagnosis, treatment, and prevention of CRKP infection in our province.

Dwarfing rootstocks are a valuable genetic resource for managing high-density plantations. The selection of the appropriate scion/rootstock combination is key to improving crop performance and sustainable production in a particular environment and specific training systems. ‘Shatangju’ mandarin scion cultivar grafted onto ‘Flying Dragon’ rootstock tends to be dwarfing and develops short stature plants. To obtain insight into potential mechanisms underlying rootstock-induced dwarfing effects, we conducted a rootstock trial to examine the influence of 11 different rootstocks based on their growth vigor, antioxidants, and hormonal levels of the scion cultivar. The phenotypic observations revealed that size reduction in the ‘Flying Dragon’ rootstock is due to lower node number, shorter internodal length, and a reduced trunk diameter of the scion compared with more vigorous rootstocks. Antioxidant analysis showed that ‘Shatangju’ mandarin grafted onto ’Flying Dragon’ and ‘Trifoliate Orange’ rootstock had significantly lower peroxidase (POD) activity than other tested rootstocks. The hormonal analysis indicated that there were markedly lower amounts of abscisic acid (ABA) in ‘Shatangju’ mandarin grafted with ‘Flying Dragon’ rootstock. In addition, trees grafted with ‘Sour Pummelo’ and ‘Flying Dragon’ depicted minimum amounts of gibberellins (GA24). Moreover, several metabolites associated with organic acids, flavonoids, amino acids, and alkaloids responded differently in plants grafted with ‘Flying Dragon’ (dwarfing) and ‘Shatang Mandarin’ (vigorous) rootstocks. This study concluded that ‘Flying Dragon’ rootstock with a strong dwarfing effect has been proposed to improve high-density cultivation methods. These findings will provide useful insights for future research associated with rootstock-mediated dwarfing mechanisms of citrus rootstocks.

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Nitrite is generated from the nitrogen cycle and its accumulation is harmful to environment and it can be reduced to nitric oxid by nitrite reductase. A novel gene from Bacillus firmus GY-49 is identified as a nirK gene encoding Cu-containing nitrite reductase by genome sequence. The full-length protein included a putative signal peptide of 26 amino acids and shown 72.73% similarity with other Cu-containing nitrite reductase whose function was verified. The 993-bp fragment encoding the mature peptide of NirK was cloned into pET-28a (+) vector and overexpressed as an active protein of 36.41 kDa in the E.coli system. The purified enzyme was green in the oxidized state and displayed double gentle peaks at 456 and 608 nm. The specific activity of purified enzyme was 98.4 U/mg toward sodium nitrite around pH 6.5 and 35 °C. The K and K of NirK on sodium nitrite were 0.27 mM and 0.36 × 10 s, respectively. Finally, homology model analysis of NirK indicated that the enzyme was a homotrimer structure and well conserved in Cu-binding sites for enzymatic functions. This is a first report for nitrite reductase from Bacillus firmus, which augment the acquaintance of nitrite reductase.