Ligand binding properties of three odorant-binding proteins in striped flea beetle Phyllotreta striolata towards two phthalate esters.

Odorant-binding proteins (OBPs) initiate insect olfactory perception and mediate specific binding and selection of odorants via uncertain binding mechanisms. We characterized the binding characteristics of four OBPs from the striped flea beetle Phyllotreta striolata (SFB), a major cruciferous crop pest. Tissue expression analysis revealed that the two ABPII OBPs (PstrOBP12 and PstrOBP19) were highly expressed mainly in the antenna, whereas the two minus-C OBPs (PstrOBP13 and PstrOBP16) showed a broad expression pattern. Competitive binding assays of cruciferous plant volatiles showed that PstrOBP12, PstrOBP16 and PstrOBP19 had very strong binding capacities for only two phthalate esters (Ki < 20 µM), and PstrOBP13 specifically bound to four aromatic volatiles (Ki < 11 µM). Fluorescence quenching assays displayed that two phthalate esters bound to three PstrOBPs via different quenching mechanisms. PstrOBP12/PstrOBP16-diisobutyl phthalate and PstrOBP19-bis(6-methylheptyl) phthalate followed static quenching, while PstrOBP12/PstrOBP16-bis(6-methylheptyl) phthalate and PstrOBP19-diisobutyl phthalate followed dynamic quenching. Homology modelling and molecular docking displayed that PstrOBP12-diisobutyl phthalate was driven by H-bonding and van der Waals interactions, while PstrOBP16-diisobutyl phthalate and PstrOBP19-bis(6-methylheptyl) phthalate followed hydrophobic interactions. Finally, behavioural activity analysis demonstrated that phthalate esters exhibited different behavioural activities of SFB at different doses, with low doses attracting and high doses repelling. Overall, we thus revealed the different binding properties of the three PstrOBPs to two phthalate esters, which was beneficial in shedding light on the ligand-binding mechanisms of OBPs.

Long Term Characteristics of Clinical Distribution and Resistance Trends of Carbapenem-Resistant and Extended-Spectrum ß-Lactamase Klebsiella pneumoniae Infections: 2014-2022.

Purpose: Through long-term and large sample size statistical analysis, we revealed the pattern of Klebsiella pneumoniae (KP) infection and drug resistance and provided epidemiological data for the treatment and prevention and control of multidrug-resistant bacterial infection in our hospital. Patients and Methods: Strains were identified using the BD PhoenixTM100 system, minimal inhibitory concentration of antibiotics were determined by the broth method, and data were statistically analyzed using WHONET 5.6 and SPSS27.0. Results: The isolation rate of KP from Enterobacteriaceae (26.2%, 4547/17358) in our hospital showed an increasing annual trend, ranking second only to Escherichia coli. Carbapenem-resistant KP (CRKP) accounted for the highest proportion of carbapenem-resistant Enterobacteriaceae (72.2%, 431/597), showing an upward trend. Infected patients had a male-to-female ratio of approximately 2:1 and were mainly >60 years of age (66.2%), with intensive care units being the most commonly distributed department. Sputum was the most common specimen type (74.0%). Compared with spring and summer, autumn and winter were the main epidemic seasons for KP and extended-spectrum ß-lactamase KP (ESBL-KP). The resistance rate of KP to common antibiotics was low, but all showed an increasing trend each year. ESBL-KP was >90% resistant to piperacillin, amoxicillin/clavulanic acid, and cefotaxime and less resistant to other common antibiotics, but showed an increasing trend in resistance to most antibiotics. CRKP resistance to common antibiotics was high, with resistance rates >90%, excluding amikacin (64.1%), gentamicin (87.4%), cotrimoxazole (44.3%), chloramphenicol (13.6%), and tetracycline (30.5%). Conclusion: KP in our hospital mainly caused pulmonary infection in older men, which occurred frequently in autumn and winter, and the isolation and drug resistance rates showed an increasing trend. Age over 70 years, admission to intensive care unit, and urinary tract infection were found to be the risk factors for CRKP and ESBL-KP-resistance.

An "immune barrier" is formed in the placenta by hepatitis B immunoglobulin to protect the fetus from hepatitis B virus infection from the mother.

The effect of hepatitis B immunoglobulin (HBIG) on hepatitis B virus (HBV) DNA load and its protective mechanism are not well understood. Twenty-eight hepatitis B surface antigen (HBsAg)-positive pregnant women and their newborns were assigned to an experimental (n = 12) or control group (n = 16) according to whether they received HBIG during pregnancy. HBV DNA load and markers titer of the mothers and newborns were tested. These markers and HBV DNA load in mothers of the experimental group did not fluctuate significantly and were comparable to the control. In the experimental group, there was a positive correlation between mothers and their newborns with regard to hepatitis B surface antibody titer. Immunohistochemical staining of placenta sections showed that HBsAg-positive areas mainly included trophoblastic cells and villous mesenchymal cells without HBIG colocalization, whereas HBIG-positive areas principally included villous capillary endothelial cells and villous mesenchymal cells. Additionally, compared with the control group, the positive rate and mean density of HBIG in the experimental group were remarkably higher. HBIG deposition was seen in Hofbauer cells. Thus, rather than influencing virus replication, HBIG forms an immune barrier between the mother and fetus to prevent HBV transmission.

Determination of clenbuterol from pork samples using surface molecularly imprinted polymers as the selective sorbents for microextraction in packed syringe.

In this study, a selective sample pretreatment procedure combing surface molecularly imprinted polymers and microextraction in packed syringe (SMIPs-MEPS) was developed for the analysis of clenbuterol (CLB) from pork samples. SMIPs for CLB were synthesized on silica gel particles through a sol-gel process. A series of characterization and adsorption experiments revealed that the SMIPs exhibited porous structures, good thermal stability, high adsorption capacity and a fast mass transfer rate. The obtained SMIPs were employed as selective sorbents of SMIPs-MEPS for extraction of CLB from pork samples. Several parameters affecting the extraction efficiency were investigated, including the pH of sample solution, number of draw-eject cycles, volume of sample, type and volume of washing solution, and the type and volume of elution solution. Under the optimized conditions, a simple and rapid method for the determination of CLB from pork samples was established by coupling with high performance liquid chromatography (HPLC). The whole pretreatment process was rapid and it can be accomplished with 2min. The limit of quantitation and the limit of detection for CLB were 0.02 and 0.009µgkg(-1), respectively. The average recoveries of CLB at three spiked levels ranged from 86.5% to 91.2% with the relative standard deviations (RSD) ≤6.3%.

[Peripheral blood mononuclear cell of neonates infected with hepatitis B virus].

OBJECTIVE: To study the mechanism and significance of peripheral blood mononuclear cell (PBMC) of neonates infected with hepatitis B virus (HBV). METHODS: Eighty-four HBsAg-positive and HBeAg-negative mothers and their newborns were recruited in this study. Sixteen hepatitis B virus markers (HBVM)-negative mothers and their neonates were served as control. All these cases had no symptoms of hepatitis, serious pregnancy complications and preexisting disease. Age, gestational age and the method of delivery were matched in two groups (P > 0.05). Five ml blood samples were taken from the peripheral vein of the pregnant women before delivery and from neonates within 24 hours after birth, before inoculation of HBV vaccine (HBVac). Serum and PBMC were isolated from 2 ml and 3 ml samples respectively. The sera, PBMC and the last supernatant of PBMC washing were stored at -80 degrees C. HBVM of neonates were detected by using enzyme linked immunosorbent assay (ELISA). HBV DNA in serum, PBMC and the last supernatant of PBMC washing of mothers and neonates were detected by using a nested-polymerase chain reaction (n-PCR). Two pairs of oligonucleotide primers, the outer primer pair for first PCR and inner primer pair for second PCR, designed according to region S of HBV genome were synthesized at Shanghai Cell Biology Institute of Chinese Academy of Sciences. The neonates who were HBV DNA positive in PBMC but HBsAg and HBV DNA negative in serum were followed up for one year, HBsAb in serum and HBV DNA in PBMC were observed in the neonates. RESULTS: (1) The positive rate of HBV DNA in 84 serum and PBMC of mothers were 53.57% and 40.48%, respectively (chi(2) = 2.891, P > 0.05). All the results were weakly positive. (2) Twenty-four (28.57%) newborns in the study group were infected, including 7 who were only HBV DNA positive in serum, 11 only HBV DNA positive in PBMC and 6 in both, all the results were weakly positive. HBsAg was negative in all the newborns. None of the neonates in control group was infected with HBV. There was significant difference between the two groups (chi(2) = 4.55, P < 0.05). (3) Of all the study cases, 11 (13.10%) neonates were HBV DNA weakly positive in PBMC but HBsAg and HBV DNA negative in serum. Of their mothers, 5 were only HBV DNA positive in serum, 2 only positive in PBMC and 4 positive in both serum and PBMC. Seven of the 11 neonates were followed up for one year and at the end of follow-up, 4 were HBsAb positive and HBV DNA negative in PBMC; 3 were HBsAb negative, and among the 3 cases HBV DNA in 2 was still positive in PBMC, HBsAg and HBV DNA in serum were negative in all the 7 neonates. CONCLUSION: (1) HBV DNA positivity either in serum or in PBMC in mothers can result in infection of PBMC with HBV in their neonates. (2) PBMC infection with HBV can exist for a long time in neonates while HBsAg and HBV DNA are negative in serum, and may result in vaccination failure in neonates.