Allosteric Probe-Based Colorimetric Assay for Direct Identification and Sensitive Analysis of Methicillin Resistance of Staphylococcus aureus.

The accurate and rapid detection of methicillin-resistance of Staphylococcus aureus (SA) holds significant clinical importance. However, the methicillin-resistance detection strategies commonly require complicated cell lysis and gene extraction. Herein, we devised a novel colorimetric approach for the sensitive and accurate identification of methicillin-resistance of SA by combining allosteric probe-based target recognition with self-primer elongation-based target recycling. The PBP2a aptamer in the allosteric probe successfully identified the target MRSA, leading to the initiation of self-primer elongation based-cascade signal amplification. The peroxidase-like hemin/G-quadruplex undergo an isothermal autonomous process that effectively catalyzes the oxidation of ABTS2- and produces a distinct blue color, enabling the visual identification of MRSA at low concentrations. The method offers a shorter duration for bacteria cultivation compared to traditional susceptibility testing methods, as well as simplified manual procedures for gene analysis. The overall amplification time for this test is 60 min, and it has a detection limit of 3 CFU/ml. In addition, the approach has exceptional selectivity and reproducibility, demonstrating commendable performance when tested with real samples. Due to its advantages, this colorimetric assay exhibits considerable potential for integration into a sensor kit, thereby offering a viable and convenient alternative for the prompt and on-site detection of MRSA in patients with skin and soft tissue infections.

Boosting H+ Storage in Aqueous Zinc Ion Batteries via Integrating Redox-Active Sites into Hydrogen-Bonded Organic Frameworks with Strong π-π Stacking.

In the emerging aqueous zinc ion batteries (AZIBs), proton (H+ ) with the smallest molar mass and fast (de)coordination kinetics is considered as the most ideal charge carrier compared with Zn2+ counterpart, however, searching for new hosting materials for H+ storage is still at its infancy. Herein, redox-active hydrogen-bonded organic frameworks (HOFs) assembled from diaminotriazine moiety decorated hexaazatrinnphthalene (HOF-HATN) are for the first time developed as the stable cathode hosting material for boosting H+ storage in AZIBs. The unique integration of hydrogen-bonding networks and strong π-π stacking endow it rapid Grotthuss proton conduction, stable supramolecular structure and inclined H+ storage. As a consequence, HOF-HATN displays a high capacity (320 mAh g-1 at 0.05 A g-1 ) and robust cyclability of (>10000 cycles at 5 A g-1 ) based on three-step cation coordination storage. These findings get insight into the proton transport and storage behavior in HOFs and provide the molecular engineering strategy for constructing well-defined cathode hosting materials for rechargeable aqueous batteries.

Target Recognition Initiated Self-Assembly-Based Signal Amplification Strategy for Sensitive and Colorimetric Staphylococcus aureus Detection and Diagnosis of Skin Infection.

Staphylococcus aureus (S. aureus), as a Gram-positive bacterium, is commonly encountered in various infectious diseases, such as acute skin and soft tissue infections. Despite that many efforts have been made, sensitive and reliable quantitative determination of S. aureus remains a huge challenge. Here, we depict a novel colorimetric approach for sensitive and accurate detection by combining allosteric probe-based target recognition and chain extension-based dual signal recycling. The single-strand DNA (ssDNA) products generated by the chain extension process lead to the liberation of G-quadruplex sequences, which can fold into active DNAzyme under the assistance of hemin. The active DNAzyme can work as peroxidase mimics to catalyze the 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS2-)-H2O2 system, causing the color change of the system. Eventually, the method exhibits a wide detection range from 103 cfu/mL to 106 cfu/mL. The limit of detection of the approach was determined 232 cfu/mL. Considering the robust capability of the approach in S. aureus detection, we believe that it will be a potential alternative tool for biomedical research and clinical molecular diagnostics.

Immobilizing Quinone-Fused Aza-Phenazine into π-d Conjugated Coordination Polymers with Multiple-Active Sites for Sodium-Ion Batteries.

The development of coordination polymers with π-d conjugation (CCPs) provides ide prospects for exploring the next generation of environmental-friendliness energy storage systems. Herein, the synthesis, experimental characterizations, and Na-ion storage mechanism of π-d CCPs with multiple-active sites are reported, which use quinone-fused aza-phenazine (AP) and aza-phenazin (AP) as the organic ligands coordinated with the metal center (Ni2+ ). Among them, NiQAP as the cathode material exhibits impressive electrochemical properties applied in sodium-ion batteries (SIBs), including the high initial/stable discharge specific capacities (180.0/225.6 mAh g-1 ) at 0.05 A g-1 , a long-term cycle stability up to 10,000 cycles at 1.0 A g-1 with a high reversible capacity of 100.1 mAh g-1 , and good rate capability of 99.6 mAh g-1 even at 5.0 A g-1 . Moreover, the Na-ion storage mechanism of NiQAP is also performed by the density functional theory (DFT) calculation, showing multiple-active sites of C≐O and C≐N (in the quinone and phenazine structure) and NiO4 (in the coordination unit) for Na-ion storage. These results highlight the importance of organic electrode material with the coordination units and provide a foundation for further studying the CCPs with multiple active sites for energy storage systems.

Identification of flavonoids in Dendrobium huoshanense and comparison with those in allied species of Dendrobium by TLC, HPLC and HPLC coupled with electrospray ionization multi-stage tandem MS analyses.

Dendrobium huoshanense, a unique species in the genus Orchidaceae, is only found in China and is known as "mihu". Due to the lack of quality control, the use of D. huoshanense in the herbal market has been limited. In this study, methods based on thin-layer chromatography, high-performance liquid chromatography and high-performance liquid chromatography coupled with electrospray ionization multi-stage tandem mass spectrometry were used to identify the flavonoids in D. huoshanense and distinguish this species from other Dendrobium species. Using thin-layer chromatography, a characteristic band was observed for D. huoshanense, and this band was absent from the thin-layer chromatography plates of other Dendrobium species. Then, using high-performance liquid chromatography, nine peaks of flavonoids were observed in the chromatograms of ten batches of D. huoshanense. Ultimately, 22 flavonoids in D. huoshanense were identified by multi-stage tandem mass spectrometry, and 11 of these compounds are being reported from D. huoshanense for the first time. In addition, two compounds both with molecular weights of 710, were identified as being unique to D. huoshanense; one of these compounds, apigenin-6-C-α-L-rhamnosyl-(1→2)-ß-D-glucoside-8-C-α-L-arabinoside, was proven to be responsible for the characteristic thin-layer chromatography band of D. huoshanense. These analysis methods can be applied for the identification and quality control of D. Huoshanense.

Altered Functional Connectivity of Amygdala with the Fronto-Limbic-Striatal Circuit in Temporal Lobe Lesion as a Proposed Mechanism for Poststroke Depression.

OBJECTIVE: Poststroke depression (PSD) is an important complication that affects stroke rehabilitation. Abnormal cortical-subcortical connectivity may be associated with the development of PSD. However, few studies have focused on the emotional network of PSD in the temporal lobe lesions. The aim of is study was to investigate amygdala-cortical functional connectivity (FC) in the temporal lobe in individuals with and without PSD. DESIGN: Twenty-three patients with PSD and 21 stroke patients without depression were recruited to undergo functional magnetic imaging scanning. RESULTS: In stroke patients with depression, the left amygdala had increased FC with the bilateral precuneus and right orbital frontal lobe but decreased FC with the right putamen. The right amygdala had increased FC with the right temporal pole, right rectus gyrus, and left orbital frontal lobe but decreased FC with the right primary sensory area (S1). Correlative analyses revealed that the amygdala's FCs with the right orbital frontal lobe, right insular cortex, and right cingulate cortex were correlated with the Hamilton Depression Rating Scale score. CONCLUSION: The current study identified mood affected through the fronto-limbic-striatal circuit in PSD. Hyperconnectivity between the amygdala, default mode network, and salience network might be related to depressive symptoms, which may provide novel insight into the underlying neuropathologic mechanisms of PSD in temporal lobe lesions.

Content Comparison of Mannose,Glucose and Narinhenin in Dendrobium officinale and Dendrobium huoshanense / 中国实验方剂学杂志

Objective: To optimize the pre-column derivation high performance liquid chromatography (HPLC) content determination method of D-mannose and D-glucose as well as the content determination method of narinhenin in Dendrobium officinale and D. huoshanense, and compare the contents of D-mannose,D-glucose and narinhenin between D. officinale and D. huoshanense. Method: A pre-column derivation HPLC method modified by Chinese Pharmacopoeia(Ch.P) 2015 was used to simultaneously determine the contents of D-mannose and D-glucose,with acetonitrile-0.02 mol·L-1 ammonium acetate solution as mobile phase for gradient elution. Kromasil 100-5 C18 was performed with the wavelength set at 250 nm,and the flow rate was 1 mL·min-1;column temperature was 30℃. HPLC content determination of narinhenin was performed on Kromasil 100-5 C18 with the acetonitrile-methanol-0.4% phosphoric acid solution as mobile phase for gradient elution,and the wavelength was set at 290 nm; the flow rate was 0.8 mL·min-1,and column temperature was 40℃. Result: D-mannose and D-glucose showed a good linear relationship within the range of 0.15-3.0 μg and 0.075-2.25 μg (r=0.999 9); and their average recoveries were 99.01% (RSD 2.1%) and 101.69% (RSD 2.0%) respectively. In addition, the other methodological researches such as repeatability and durability all met the requirements. The contents of D-mannose(Cm),D-glucose(Cg) and sum of them (Cm+Cg) were 12.75%-36.40%,2.93%-18.39% and 19.23%-54.58% in 43 batch of D. officinale. Almost all of the results except very few samples reached the D-mannose standard in Ch.P 2015, and the total content of D-mannose and D-glucose was also up to the total polysccharide standard in Ch.P. The correlation between content and origin was not significant. The contents of D-mannose(Cm),D-glucose(Cg) and sum of them (Cm+Cg) were 14.33%-29.47%,6.64%-15.20%,and 25.73%-44.37% in 12 batch of D. huoshanense. These contents and ratio of peak areas of D-mannose to D-glucose (Am/Ag) were within the scope of D. officinale's; in addition, their average contents were basically the same with those in D. officinale (about 33%).Next,naringenin showed a good linear relationship within the range of 0.020 8-0.832 0 μg (r=0.999 9),and its average recovery was 101.96% (RSD 1.8%). The content of naringenin was 0.053 2-0.122 4 mg·g-1 (average value of 0.081 0 mg·g-1) in 11 batch of D. officinale, slightly higher than 0.040 3-0.090 0 mg ·g-1 (average value of 0.068 3 mg ·g-1) in 7 batch of D. huoshanense. All of these results of narinfenin did not reach the content lower limit in Ch.P. Conclusion: The method used to determinate the content of D-mannose and D-glucose is reproducible, and their sum content is possible to substitute the total polysccaride determination (with higher errors) in D. officinale; monosaccharide content determination can be used for quantitative quality control of D. huoshanense. However, it could not distinguish D. officinale and D. huoshanense by determining the contents of polysccharide,D-glucose,D-mannose and narinhenin, and shall be combined with other specificity methods for further identification.

HPLC Characteristic Spectrum Optimization of Flavonoid Glycosides on Dendrobium officinale and Characteristics Analysis of Different Provenances / 中国实验方剂学杂志

Objective: To optimize the HPLC characteristic spectrum of flavonoid glycosides of Dendrobium officinale,and identify the common and specific components of different provenances. Method: Kromasil 100-5 C18 column was adopted, with tetrahydrofuran-acetonitrile-methanol (10:22:5)-0.05% phosphoric acid as mobile phase (gradient elution). The detection wavelength was 340 nm,the column temperature was 30℃,and the flow rate was 1.0 mL ·min-1. Result: 13 flavonoid characteristic peaks were marked in 27 batches of D. officinale,and 7 characteristic peaks of 6 flavonoid C-glycosides (vicenin Ⅱ,vicenin Ⅰ,schaftoside,isoschaftoside,violanthin and isoviolanthin) and one flavonoid O-glycosides (rutin) was identified. 7-11 characteristic peaks were detected in different batches of samples. Among them,vicenin Ⅱ was a relatively stable common peak in different source samples,and the characteristic peaks of rutin,schaftoside and isoschaftoside were quite different. According to the relative abundance of the characteristic peaks,the samples could be divided into three categories. Among them,the first category had 10 batches of samples,which mainly came from Danxia landforms of Guangdong,Jiangxi,Fujian and Zhejiang (Wuyi) Province (which called "Danxia landform species") and characterized by detection of obvious peak of rutin. The second category had 11 batches of samples,which mainly came from Yunnan and Guangxi Province (which included "Yunnan Guangnan species" and "Guangxi Tiepilan species") and characterized by detection of violanthin and isoviolanthin. And the third category had 6 batches of samples, which were mainly derived from Zhejiang Province (which called "native species from Zhejiang") and characterized by detection of different degrees of rutin peak, but it was difficult to detect the characteristic peaks of violanthin and isoviolanthin. HPLC characteristic chromatograms of D. officinale in bionics wild cultivation and greenhouse of "Danxia landform species" and "Guangxi Tiepilan species" were compared. The results showed that the characteristic peaks in D. officinale planted in greenhouse could be detected stably,which verified the reliability of the source in D. officinale. Conclusion: The analytical method has a better separation effect on flavonoids of D. officinale, with a good reproducibility. The commonness and specificities of flavonoid glycosides components of D. officinale from different categories have basically confirmed. This suggests that Vicenin Ⅱ is suitable to be a reference peak for characteristic chromatogram. Both the relative abundance of rutin and the detection or relative abundance of violanthin and isoviolanthin peaks could be used as a reference to judge the categories of D. officinale in "Danxia landform species" or "Tiepilan species from Yunnan, South Guangdong and Guangxi" or "native species from Zhejiang".

[The immunological effects of three doses of a live attenuated hepatitis A vaccine (H2 strain) in 8 years].

OBJECTIVE: To observe the immunological effects of three doses of H2 strain live attenuated hepatitis A vaccine 8 years after the administration and to compare with that of one dose of the vaccine. METHODS: In a country area, 110 children of 1 to 7 years old susceptible to HAV were screened and administered with one dose of the vaccine, as group B; Group A were 42 children from one of the villages and administered with 3 doses of the vaccine according to 0, 2, 6 month schedule. Blood samples were taken for the children 1, 2, 6, 7, 8, 12, 24, 36 and 96 months after the administrations respectively and detected for anti-HAV antibody. RESULTS: For group B, the sero conversion rate of anti-HAV and GMC reached peak at 92.2% and 126.2 mIU/ml respectively, and then, began to drop with time; For group A, after 2 dose of the vaccine, the sero-conversion rate reached 100%, and the GMC reached peak of 2 739 mIU/ml one month after the third dose at 7 months. So that, group A has a better short-term immunological effects than that of group B. During 36 through 96 months, the anti-HAV positive rate in group B was 75%-71% and 80-89 mIU/ml respectively, and comparatively in group A were 100% and 918.2-480.6 mIU/ml respectively. The differences between group A and B were significantly important. CONCLUSION: A 3-dose schedule administration of H2 strain live attenuated hepatitis A vaccine has better immunological effects than 1-dose schedule in 8years and further observations are needed.

Optimization of cellular nucleotide extraction and sample preparation for nucleotide pool analyses using capillary electrophoresis.

Cell extraction and further sample preparation for nucleotide pool analysis using capillary electrophoresis was faster and simpler using volatile extraction solvents (e.g. organic solvents and de-ionized water) compared to the commonly applied acids dissolved in water (e.g. perchloric acid and trichloracetic acid). Temperature had to be controlled during the whole sample preparation process to prevent degradation, and extracts had to be cleaned from proteins and other large molecules prior to capillary electrophoretic analysis to improve reproducibility. Capillary electrophoresis using borate and cyclodextrins in the background electrolyte was used for determining 11 cellular nucleotides simultaneously. In order to optimize the assay, 0-100% acetonitrile, 0-100% ethanol, and 0-100% methanol in de-ionized water were applied to extract nucleotides from mouse lymphoma cells, and nucleotide yields, recovery, and reproducibility were compared. The assay met the commonly accepted validation limits for biological fluids, if 20-80% acetonitrile in water and 40-60% ethanol in water were used as extraction solvents.