Development of Fish Immunity and the Role of β-Glucan in Immune Responses

Administration of β-glucans through various routes, including immersion, dietary inclusion, or injection, have been found to stimulate various facets of immune responses, such as resistance to infections and resistance to environmental stress. β-Glucans used as an immunomodulatory food supplement have been found beneficial in eliciting immunity in commercial aquaculture. Despite extensive research involving more than 3000 published studies, knowledge of the receptors involved in recognition of β-glucans, their downstream signaling, and overall mechanisms of action is still lacking. The aim of this review is to summarize and discuss what is currently known about of the use of β-glucans in fish.     

A comparison of the inclusion behavior of human serum albumin and holo transferrin with fluoxymesterone in the presence of three different cyclodextrins

This article describes the interaction of fluoxymesterone (Flu) with HSA and HTF in the absence and presence of cyclodextrins (CDs) (α, β and γ). According to fluorescence data, the binding of Flu to the proteins caused strong static quenching in the binary and ternary systems. The fluorescence quenching results demonstrated that HSA and HTF had two and one class of apparent binding sites with a distinct binding constant in the presence of the CDs, respectively. The effects of Flu on the structure of HSA and HTF were analyzed using synchronous fluorescence spectroscopy, which showed that the interaction of Flu with both proteins in the binary and ternary systems altered the microenvironment around the Trp and Tyr residues. The distance, r, between Flu and the proteins was obtained according to FRET which pointed at a successful formation of a drug-protein complex. Far-UV CD spectra indicated that the binding of the drug to both proteins induced changes in the secondary structure of HSA and HTF in the binary and ternary systems. Finally, molecular modeling provided possible binding sites of Flu within the proteins for the binary and ternary systems and also confirmed the experimental results. The obtained data can be useful for determining usage drug doses in drug delivery.     

Silver,iron, and nickel immobilized on hydroxyapatite‐core‐shell γ‐Fe2O3 MNPs catalyzed one‐pot five‐component reactions for the synthesis of tetrahydropyridines by tandem condensation of amines,aldehydes, and methyl acetoacetate

In this study, Ag, Ni²⁺, and Fe²⁺ immobilized on hydroxyapatite‐core‐shell γ‐Fe₂O₃ nanoparticles (γ‐Fe₂O₃@HAp‐Ag, γ‐Fe₂O₃@HAp‐Ni²⁺, and γ‐Fe₂O₃@HAp‐Fe²⁺) as a new and reusable Lewis acid magnetic nanocatalyst was successfully synthesized and reported for an atom economic, extremely facile, and environmentally benign procedure for the synthesis of highly functionalized tetrahydropyridines derivatives 4a‐t is described by one‐pot five‐component reaction of 2 equiv of aldehydes 1 , 2 equiv of amines 2 , and 1 equiv of methyl acetoacetate 3 in EtOH at room temperature in good to high yields and short reaction time. The presented methodology offers several advantages such as easy work‐up procedure, reusability of the magnetic nanocatalyst, operational simplicity, green synthesis avoiding toxic reagents and solvent, mild reaction conditions, and no tedious column chromatographic separation.     

Sol–gel template synthesis of luminescent glass–ceramic rods

We report an original way to prepare luminescent glass–ceramic microrods containing Eu³⁺ doped BaF₂ nanocrystals by sol–gel chemistry within the pores of a polycarbonate template membrane. Structural characterization by scanning electron microscopy and X-ray diffraction has shown the formation of glass–ceramic microrods with 0.8-m diameter of and 10 μm length in which BaF₂ nanocrystals of about 30 nm size are embedded. Photoluminescence measurements have indicated the incorporation of Eu³⁺ ions inside the BaF₂ nanocrystals in a broad range of sites with low coordination symmetry. The comparison made with the bulk glass–ceramic indicated an influence of the dimensional constraints imposed by the membrane pores during xerogel formation and subsequent glass ceramization.     

雷云电场作用下长地线表面正极性辉光电晕放电的仿真研究

在雷云电场的缓慢作用下, 一种无流注的正极性辉光电晕在接地物体表面起始, 向周围空间注入大量正极性空间电荷, 从而改变雷电先导对雷击目的物的选择. 本文对雷云电场作用下起始于长地线表面的正极性辉光电晕放电进行了仿真研究; 考虑了正极性离子与其他离子的附着与碰撞作用, 建立了一种精确的二维正极性辉光电晕模型; 并通过在实验室内开展高压电晕放电试验, 测量了不同背景电场下的电晕电流; 与本文所建模型的仿真结果进行对比, 对模型的正确性进行了验证. 基于上述模型, 对正极性辉光电晕在雷云感应作用下的起始发展过程与电晕特性进行了仿真模拟, 得到了该电晕的电晕电流、正离子密度分布规律以及正离子迁移规律. 发现在雷云电场作用下, 电晕放电产生的正离子在迁移初期于垂直于地线的平面内基本呈圆对称状均匀分布, 但随着离子逐渐远离地线其分布不再均匀, 呈拉长的椭圆形分布, 多数离子最终分布于地线上方区域并逐渐向雷云方向迁移; 由于正离子在地线上方迁移区聚集形成的正空间电荷背景对行进电子束具有衰减和消耗作用, 抑制了电子崩的形成, 并降低了电子崩转化为流注的概率, 阻止了新的电子崩对流注的不断注入, 同时正空间电荷背景使气体的碰撞面增大, 增加了与电子的复合概率, 引起大量电子的消耗, 最终抑制了电子崩的形成与流注的发展, 地线表面的上行先导得到抑制.     

FRET based selective and ratiometric ‘naked-eye’ detection of CN in aqueous solution on fluorescein–Zn–naphthalene ensemble platform

We have developed a FRET-based ratiometric fluorescent probe for the detection of CN⁻ using a fluorescein–Zn–naphthalene ensemble (NFH·Zn²⁺). The sensing mechanism was ascribed by displacement approach. The chemosensor exhibits high selectivity and sensibility for CN⁻. The speculation was supported by fluorescence emission spectra, UV–vis spectrum, ¹H NMR titration experiments, and mass spectra. The interconversion of probe NFH and NFH·Zn²⁺ via the complexation/decomplexation by the modulation of Zn²⁺/CN⁻ mimics INHIBIT gate. In addition, it also shows an excellent performance in ‘dip stick’ method.     

Spectroscopic analysis of the interaction between Co3O4 nanoparticles and acid phosphatase

Monatshefte für Chemie - Chemical Monthly - In this study, the structure and stability of acid phosphatase in its interaction with Co3O4 nanoparticles are evaluated through absorbance, enzyme...     

Thin films of vitronectin transferred by MAPLE

We report on matrix-assisted pulsed laser evaporation (MAPLE) transfer of intact and functional protein molecules from a cryogenic aliquot obtained by freezing a protein-saline buffer solution. Vitronectin (Vn), an extracellular matrix protein with distinctive active domains for cell attachment and signalization, was expelled from frozen targets by KrF* excimer laser irradiation, and then immobilized on substrates. Particulates surrounded by a dense matrix were observed by optical, profilometry and AFM studies. The composition preservation of MAPLE-deposited protein films versus drop-cast films was demonstrated by FTIR and immunostaining studies. The stability and integrity of Vn after transfer was shown by their interaction with human osteoprogenitor cells in which actin filaments stretched across the entire cell area and clear focal points with surface were formed. The absence of detectable degradation of protein structure after MAPLE immobilization could provide benefits to surface functionalization for biomedical applications.     

A turn on ESIPT probe for rapid and ratiometric fluorogenic detection of homocysteine and cysteine in water with live cell-imaging

5(Benzothiazol-2-yl)-4-hydroxyisophthalaldehyde (BHI), an intense ESIPT containing molecule in mixed media loses its properties due to resonance-assisted H-bond (RAHB) in absolute water. Due to resonance-assisted H-bond the o-aldehyde is more reactive than the other one. With addition of cysteine/homocysteine into this solution the o-aldehyde group gets transformed into thiazolidine/thiazine ring, respectively, and the phenolic proton becomes free enough for transfer to nitrogen of the benzothiazole ring in excited state, that is, the ESIPT of BHI is turned on. Thus we can detect cysteine/homocysteine in water as well as in live cells.