查找使用阿拉丁产品的科研文献

Development of Sandwich ELISA and Immunochromatographic Strip for the Detection of Peanut Allergen Ara h 2

Peng Juan,Song Shanshan,Liu Liqiang,Kuang Hua,Xu Chuanlai

In order to develop highly sensitive immunoassays for detecting the major peanut allergen, Ara h 2, we prepared six monoclonal antibodies (mAb) with high affinity to Ara h 2. Using mAb 5 as a capture antibody and HRP-labeled mAb 1 as a detection antibody, a sandwich enzyme-linked immunoassay (ELISA) was established with a limit of detection (LOD) of 0.02 ng/mL. An immunochromatographic strip based on these two mAbs was also established with a LOD of 1 ng/mL. Both tests showed high specificity in cross-reactivity experiments. Sample analyses indicated that these two immunoassays were feasible, accurate, and highly sensitive for measuring allergen Ara h 2 of food.

H-2 increases oxidative stress resistance through DAF-16/FOXO pathways in Caenorhabditis elegans: A new approach to vitiligo treatment

Xingzhuo Song,Yu Du,Cen Liu,Wei Wang,Jing Han,Xinlou Chai,Yonggang Liu

Oxidative stress disrupts the homeostasis of the redox state in cells and induces apoptosis. Prolonged oxidative stress can impair the normal function of cells, tissues, and organs and lead to the development of several diseases. H-2 was synthesized by derivatising N- Alkylamides (NAAs) from Anacyclus pyrethrum (L.) DC, which is commonly used in the treatment of vitiligo in Uyghurs. The antioxidant activity and potential molecular mechanisms of H-2 were investigated using Caenorhabditis elegans ( C. elegans ) and mouse melanoma cell B16-F10 models. The in vivo anti-vitiligo activity of H-2 was studied using C57BL/6 mice. The results showed that H-2 could increase the survival time of nematodes under oxidative stress, promote the nuclear localization of DAF-16, and enhance the expression of Superoxide Dismutase 3 (SOD-3) in nematodes thereby activating the antioxidant enzyme system. H-2 could affect the survival rate of age-1 and akt-1 mutants under oxidative stress. H-2 could reverse the oxidative stress damage by reducing the reactive oxygen species (ROS) content in the Hydrogen peroxide (H 2 O 2 ) -induced oxidative stress damage model of mouse melanoma cells B16-F10. In addition, it was also able to increase the number of melanocytes in the hair follicles of vitiligo model mice and improve the phenomenon of skin damage in mice. In conclusion, our findings suggest that H-2 can alleviate oxidative stress damage in C. elegans and B16-F10, which may be associated with oxidative stress, suppression of antioxidant defences, and transcription factors DAF-16/FOXO, providing beneficial evidence for the application of H-2 in the vitiligo treatment.

The decrease of Ara h 2 allergenicity by glycation is determined by reducing sugar chain length and isomers

Ping Yang,Xumei Wang,Hui Wang,Yueming Hu,Pingwei Wen,Zongcai Tu

The mechanism of the effect of reducing sugar chain length and isomers on the allergenicity of Ara h 2 after glycation was investigated. Ara h 2 was more prone to glycation with ribose which had a short chain length. The glycation sites of Ara h 2 after glycation with galactose were higher than the glycation sites in galactose’s isomers-Ara h 2 conjugates, which might be affected by the configuration differences at position C-4 and the small steric effects in terminal groups –CHO of galactose. Ara h 2-ribose conjugate had the lowest allergenicity, and glycation with galactose was more capable of reducing Ara h 2 allergenicity than its isomers. The results indicated that glycation with ribose caused conformational epitope destruction and linear epitope masking of Ara h 2 greatly. Furthermore, since the small steric effects of –CHO, galactose was more capable of reducing Ara h 2 allergenicity than fructose. This study will provide a theoretical basis for selecting appropriate reducing sugars and preparing hypoallergenic products containing peanuts.

Exploration of Non-Covalent Interactions of Peanut Allergen Ara h 2 With Tannic Acid: Insights Into Molecular Structure and In Vitro Allergenicity

Qin Geng,David Julian McClements,Taotao Dai,Wenlong Zhou,Zhihua Wu,Hongbing Chen

The molecular structure and surface properties of peanut proteins are altered by their non-covalent interactions with food polyphenols, which alter their allergenicity. In our research, the interactions between the critical peanut allergen (Ara h 2) and a model polyphenol (tannic acid [TA]) were studied utilizing experimental (spectroscopy and calorimetry) and molecular docking methods. Ultraviolet (UV) and circular dichroism (CD) spectroscopy analysis indicated that the microenvironment polarity and secondary/tertiary structure of Ara h 2 were changed due to its interaction with TA. Specifically, degree of molecular disorder increased, and the surface hydrophobicity of the polypeptide decreased after Ara h 2 interacted with TA. Analysis using fluorescence quenching, isothermal titration calorimetry, and molecular docking showed that the main non-covalent interactions were hydrogen bond formation between the Ara h 2 and TA. Binding site analysis using molecular docking indicated that the TA may have interacted with specific amino acids in the polypeptide chain, including Lys 31, Arg 34, Asp 35, Trp 44, Ser 54, Arg 59, Arg 60, Arg 122, Glu 123, and Gln 130. These amino acids are known to be part of the IgE epitope regions of Ara h 2, and so TA binding might be expected to impact peanut protein allergenicity. Indeed, an enzyme-linked immunosorbent assay (ELISA) study indicated that the IgE binding capacity of Ara h 2 was reduced after interacting with TA in a dose-dependent manner. This study enriches the understanding of the interactions between peanut protein allergens and small-molecule nutrients and provides a method for reducing the potential allergenicity of Ara h 2. Practical applications Employing the plant polyphenols as a means to modulate the activity of food allergens could potentially offer a breakthrough in managing food allergies. The strategic non-covalent binding of polyphenols, exemplified by TA, to the peanut allergen Ara h 2, may effectively lower its capacity to trigger allergic reactions, thereby offering an approach to mitigating peanut sensitization risks. The study examined the alterations in the structure and allergenic properties of Ara h 2 following its interaction with TA. This investigation was poised to accelerate the identification of TA's potential to inhibit peanut-induced allergic responses through allergen binding.

Impact of the Polyphenol Structure on the Allergenic Potential of the Peanut Allergen Ara h 2

Kuan Gao,Qin Geng,Changbao Hu,Wenhui Zhang,Xin Li,Ping Tong,Anshu Yang,Zhihua Wu,Hongbing Chen

Interactions between food allergens and polyphenols can provide a method to alleviate food allergies. This study investigated the effect of differently structured polyphenols complexed with Ara h 2 based on high-throughput virtual screening, utilizing a spectroscopic, thermodynamic, bone marrow-derived dendritic cells (BMDCs) model, BMDCs-T cells coculture model, KU812 cells model, and molecular simulation analyses for the allergenicity evaluation. Hesperidin (HSD), neohesperidin (NH), and neohesperidin dihydrochalcone (NHDC) exhibited a high binding energy and interacted with Ara h 2 through hydrogen bonding, primarily at two additional binding sites. This interaction led to protein unfolding and reduced hydrophobicity, particularly in the NH–Ara h2 complex. In addition, NH-bound Ara h2 has a lower potential for sensitization due to its reduced immunoglobulin E (IgE) binding capacity compared with Ara h 2 during gastrointestinal digestion. This is further supported by the decreased expression of costimulatory factors in BMDCs, the reduced release of allergenic cytokines, and the maintained balance of Th1, Th2, Th17, and Treg. The same trend was followed by the HSD and NHDC complexes. These findings suggest that glycosidic bond positions play a more significant role in reducing sensitization than does the flavonoid structure. Therefore, this study can assist in developing oral-specific immunotherapy of individuals with peanut allergies under the potential interaction mechanism of polyphenols and Ara h 2.

Impact of Quercetin on the Allergenic Potential of Peanut Protein Ara h 2 During pH-Shifting

Kuan Gao,Qin Geng,Wenhui Zhang,Xin Li,Ping Tong,Anshu Yang,Zhihua Wu,Hongbing Chen

The effects of pH-shifting combined with quercetin binding on peanut Ara h 2 were evaluated using multispectroscopy, cell models, molecular simulation, and correlation analysis. After dual treatment, Ara h 2 exhibited significant structural changes, as evidenced by decreased intrinsic fluorescence and converted α-helix into β-sheet, leading to reduced IgE-binding capacity and diminished ability of dendritic cells and T cells to differentiate toward the Th2 pathway due to the masking of epitopes. Moreover, the binding sites of quercetin gradually shifted toward the hydrophobic core of Ara h 2 with pH changes, which inhibited fluctuations in the aa50–70 region. Finally, according to the correlation analysis, pH-shifting combined with quercetin binding may reduce the allergenicity of Ara h 2 by the migration of many Trp and Tyr residues to the protein surface, which disrupted the conformational epitopes. Therefore, this study provides an approach for the development of hypoallergenic peanut products.

Manipulating d-Band Center of Cu(I)-MOFs for Catalytic Ignition of [BMIM]N(CN) 2 IL-H 2 O 2 Propellants

Qing Cheng,Yuqi Zhang,Yingying Cao,Long Liu,Yanqiang Zhang

The novel ionic liquid-H2O2 propellants are urgently to solve the intrinsic ignition problem for achieving the aerospace applications. We addressed this issue by tuning the d-band center to adjust the catalyst's adsorption strength for IL/H2O2 toward the optimal value, thus enhancing catalytic activities for the efficient decomposition of H2O2 to generate reactive oxygen species. Herein, the regulation of the d-band center of Cu(I) in Cu(I)-MOF catalyst by precise ligand engineering design was studied. Remarkably, The Cu-S3 coordination of Cu-SH' shifts its d-band center closer to the Fermi level, promoting the adsorption of [BMIM]N(CN)2 and H2O2. Cu-SH' enables efficient H2O2 activation and robust •OH and 1 O2 generation to trigger the rapid self-ignition of [BMIM]N(CN)2-H2O2 propellant. The resulted tid as low as 18.4 ms is nearly 34% lower than that of homogeneous catalyst [FcCH2N(CH3)3]2[Cu2I4]. This work provides fundamental insights into the design of efficient ligand-based combustion catalysts for the higher performance of rockets and spacecrafts.

Fenton reaction-assisted photodynamic inactivation of calcined melamine sponge against Salmonella and its application

Qiandai Shi,Jing Jing Wang,Lu Chen,Zhiyun Peng,Qiao-Hui Zeng,Yongheng Zhu,Yong Zhao

Photodynamic inactivation (PDI) is an effective alternative to traditional antibiotics to broadly kill bacteria. This study aimed to develop a potent PDI system by coupling calcinated melamine sponges (CMSs) with the Fenton reaction. The results showed that CMS calcined at 350 ℃ was successfully carbonized with intact and porous structures, and it possessed excellent hydrophilicity and photothermal conversion performance. When Fe 2+ was added and internalized, the Fenton reaction in which Fe 2+ reacted with H 2 O 2 in cells occurred to produce reactive oxygen species (ROS) ( OH, OOH, etc.) and O 2 , and notably, the O 2 molecules could serve as a raw material to absorb the photothermal energy of CMS to generate highly reactive 1 O 2 . Under synergistic effects, CMS-350 coupled with Fe 2+ potently inactivated > 6 Log CFU/mL (>99.9999%) of Salmonella under 201.6 J/cm 2 blue LED illumination by destroying Na + /K + -ATPase and Ca 2+ /Mg 2+ -ATPase, DNA synthesis-related enzymes, cell membranes, etc. Meanwhile, the composite photocatalyst was proven to be nontoxic and could inactivate Salmonella in various foods, including vegetables ( Brassica chinensis L), eggs and fresh cucumber juice. As a result, CMS coupled with the Fenton reaction greatly improves the inactivation potency of PDI against harmful bacteria.

Effect of ${\rm H}_{2}$ on the Formation Mechanism and Magnetic Properties of FePt Nanocrystals

B. R. Bian,W. X. Xia,J. Du,J. Zhang,J. P. Liu,Z. H. Guo,A. R. Yan

Metal-Phenolic network pH-Sensitive Nanoparticle-Enabled Chemo/Chemodynamic therapy for lung cancer

Daiwang Shi,Siyi Li,Wenhan Liu,Liang Song,Ran Xu

Lung cancer is a serious disease and the leading cause of cancer-related death. Metal-phenolic network nanoparticles have been proposed as a promising strategy for cancer therapy. In this work, eight-arm PEG succinimidyl glutarate, copper ions and doxorubicin (DOX) were integrated into one nanoparticle via hydrophobic interactions and coordination interactions to achieve chemotherapy (CT) and chemodynamic therapy (CDT). [email protected] accumulated in tumour tissue and released DOX and Cu 2+ into the tumour microenvironment. Cu 2+ reacted with GSH to form Cu + . Cu + continued to react with H 2 O 2 to form •OH. DOX killed lung cancer cells and activated NOX4, up-regulating the endogenous H 2 O 2 level and further enhancing the efficiency of CDT. In vitro and in vivo experiments demonstrated that [email protected] has superior biological safety and can inhibit the growth of lung cancer tumours via synergistic CT/CDT. This research offers a new strategy for the construction of metal-phenolic network nanoparticles for the synergistic treatment of lung cancer by CT/CDT.

A novel phosphinic acid extractant and its application in the effective extraction of Mn2+ from Mn2+-Mg2+ sulfate solution

Xintong Li,Yongna Guo,Xin Ma,Chao Zhang,Jia Yang,Shuai Wang

Herein, a series of α -hydroxyalkyl phosphinic acids were designed and first introduced in Mn 2+ extraction and Mn 2+ -Mg 2+ separation. The extraction tests indicate that the α -hydroxy-2-ethylhexyl phosphinic acid ( α -H-2-EHA) possesses superior extraction ability compared to di-2-ethylhexyl phosphinic acid (P204) for Mn 2+ and Mg 2+ , and the partition coefficient ( β ) is 28.2 at a saponification ratio of 30%. The results of quantum chemical calculation, FT-IR spectrum and slope analysis method reveal that the α -H-2-EHA can form stable four-membered ring structure with metal ions during the extraction process through P–OH and P O bonds. Furthermore, the HOMO composition results suggest that α -OH might also promote the interaction between extractant and metal ions. Finally, a three-stage countercurrent extraction—washing—stripping process was proposed and Mn 2+ can be enriched from 11.2 g/L to 36.6 g/L, with Mg 2+ decreased from 30.3 g/L to 0.6 g/L, which provides an efficient strategy for the preparation of high-purity manganese.

Uptake Kinetics of \({\text{NH}_{4}^{+} }\), \({\text{NO}_{3}^{-} }\) and \({\text{H}_{2}\text{PO}_{4}^{-} }\) by Typha orientalis, Acorus calamus L., Lythrum salicaria L., Sagittaria trifolia L. and Alisma plantago-aquatica Linn

Kunlun Wang,Qian Hu,Yumin Wei,Hui Yin,Changhong Sun,Guizhong Liu

The emergent plants may differ in their capacity to assimilate nutrients from eutrophic water bodies, so the utilization of suitable emergent plants is the key part for successful restoration of shallow eutrophic lakes and rivers. This research applied the depletion method to study the kinetics of uptake of nutrient (H2PO4−,NH4+,NO3−) in different nutrient stresses by the five emergent aquatic plants (Acorus calamusL.,Typha orientalis, Lythrum salicariaL.,Sagittaria trifoliaL.,Alisma plantago-aquaticaLinn) in the riverine zones of Dashi River (39°30′–39°40′ N, 115°59′–116°5′ E), a shallow eutrophic river located in Fangshan District, Beijing. The results showed that at the three phosphorus levels,A. calamusandA. plantago-aquaticahad the highest maximum uptake rate values forNH4+under low to moderate phosphorus conditions, and high phosphorus, respectively.T. orientalishad the highest maximum uptake rate values forNO3−at all phosphorus concentrations, while the Michaelis-Menten constant values ofL. salicariaandA. plantago-aquaticawere smaller. At the three nitrogen levels, the maximum uptake rate values forH2PO4−were the greatest forA. plantago-aquaticaat the low to moderate nitrogen levels andL. salicariaat high levels. Meanwhile,T. orientalisandL. salicariahad the smallest Michaelis-Menten constant values. In this study, nitrogen microbial transformations, such as nitrification, denitrification and their coupling were not measured and their role in measuring kinetics was not assessed. Thus, achieved results shall be considered as a synthesis of several processes mediated by plants, a theoretical guidance to the selection of plant species for phytoremediation of polluted water bodies with different nutrient stresses for quality improvement around the diverse rivers in Haihe River basin.Keywords:emergent plants;eutrophication;nitrogen;phosphorus;uptake kinetics;stress