Heteropoly acids as solid green Brønsted acids for a one-pot synthesis of beta-acetamido ketones by Dakin-West reaction

An efficient improved procedure for the synthesis of beta-acetamido ketones has been developed by a heteropoly acid (HPA) catalyzed three-component coupling protocol. The present methodology offers several advantages such as excellent yields, simple procedure, short reaction times, and mild conditions.     

Effect of the entomopathogenic fungus,Beauveria bassiana,and its secondary metabolite on detoxifying enzyme activities and acetylcholinesterase (AChE) of the Sunn pest,Eurygaster integriceps (Heteroptera: Scutellaridae)

The effects of Beauveria bassiana spores and its secondary metabolite on insect resistance to an organophosphorus insecticide, fenitrothione and secondary metabolite effects on acetylcholine esterase inhibition were investigated. Findings showed that fungal spores and its secondary metabolite increase total esterase and glutathione S-transferase activities in the hemolymph of infected and treated adults of Eurygaster integriceps. But the fungal secondary metabolite had an adverse effect on AChE activity of adults that decreased its activity level and isoforms of this enzyme in polyacrylamide gel electrophoresis. Fungal infection decreased the susceptibility of E. integriceps adults to fenitrothione, in comparison with uninfected individuals. Possible involvement of detoxifying enzymes in the development of insect resistance to fenitrothione should be considered in combined usage of chemicals and microbial agents for integrated pest management programs.     

Identification of Four Novel Rhipicephalus annulatus Upregulated Salivary Gland Proteins as Candidate Vaccines

The control of Rhipicephalus annulatus ticks in Egypt and other countries relies principally on the application of acaricides which have many drawbacks. Recently, cattle vaccination against ticks showed a potential unconventional approach to control ticks. As a target, salivary glands contain various proteins that may play specific roles during attachment, feeding and may modulate the immune system of the host. We have performed immunoscreening on expression normalized cDNA library to identify unique R. annulatus proteins from salivary gland (RaSal) that are particularly expressed during engorgement. We also present the cloning and sequencing of four novel cDNAs (RaSal1–4) from salivary glands that are expressed during feeding. RaSal4 shows 13 cysteine amino acid residues forming 6 potential disulfide bonds. We detected the expression level of the four genes during embryogenesis in eggs collected at 6, 12 and 18 days after oviposition. RT-PCR analysis detected these proteins at days 12 and 18 while slight amplification was detected at day 6 for only RaSal2. The expression of these salivary genes may put forward new vaccines to control tick infestations and tick-borne diseases.     

Co-Stimulation through 4-1BB/CD137 Improves the Expansion and Function of CD8+ Melanoma Tumor-Infiltrating Lymphocytes for Adoptive T-Cell Therapy

Adoptive T-cell therapy (ACT) using tumor-infiltrating lymphocytes (TIL) can induce tumor regression in up to 50% or more of patients with unresectable metastatic melanoma. However, current methods to expand melanoma TIL, especially the “rapid expansion protocol” (REP) were not designed to enhance the generation of optimal effector-memory CD8⁺ T cells for infusion. One approach to this problem is to manipulate specific co-stimulatory signaling pathways to enhance CD8⁺ effector-memory T-cell expansion. In this study, we determined the effects of activating the TNF-R family member 4-1BB/CD137, specifically induced in activated CD8⁺ T cells, on the yield, phenotype, and functional activity of expanded CD8⁺ T cells during the REP. We found that CD8⁺ TIL up-regulate 4-1BB expression early during the REP after initial TCR stimulation, but neither the PBMC feeder cells in the REP or the activated TIL expressed 4-1BB ligand. However, addition of an exogenous agonistic anti-4-1BB IgG₄ (BMS 663513) to the REP significantly enhanced the frequency and total yield of CD8⁺ T cells as well as their maintenance of CD28 and increased their anti-tumor CTL activity. Gene expression analysis found an increase in bcl-2 and survivin expression induced by 4-1BB that was associated with an enhanced survival capability of CD8⁺ post-REP TIL when re-cultured in the absence or presence of cytokines. Our findings suggest that adding an agonistic anti-4-1BB antibody during the time of TIL REP initiation produces a CD8⁺ T cell population capable of improved effector function and survival. This may greatly improve TIL persistence and anti-tumor activity in vivo after adoptive transfer into patients.     

Surfactant protein C and lung function: new insights into the role of α-helical length and palmitoylation

Surfactant protein C (SP-C) is known to be essential for lung function and the formation of a surface confined reservoir at the alveolar interface. The structural features relevant for the peptide’s extraordinary ability to form extended three-dimensional structures were systematically investigated and are summarized in the present paper. The influence of palmitoylation was studied for full length SP-Cs as well as truncated variants with the N-terminal residues 1–17 and 1–13, respectively. The combined results from film balance measurements, fluorescence microscopy (FLM) and scanning force microscopy (SFM) reveal a fine-tuned balance between the influence of the palmitoyl chains and α-helical length. Native SP-C added to DPPC/DPPG monolayers (molar ratio 80:20) induced the formation of the surface confined reservoir independent of its palmitoylation degree. However, topographic images revealed that only bilayers and not multilayers where formed when the acyl chains were missing. The influence of palmitoylation increased when α-helical length was considerably reduced to 17 or even 13 amino acid residues. In these strongly truncated SP-C peptides palmitoyl chains increased monolayer stability and anchored the peptides in the lipid film. However, no multilayer formation was observed at all for all shortened peptides. The α-helix of SP-C seems to be a prerequisite for the formation of extended three-dimensional structures and obviously has to be able to span a lipid bilayer. Palmitoylation obviously mediates interactions between lipids and/or peptides not only within a protein/lipid film but also between neighbouring layers and induces a stacking of bilayers. Dedicated to Prof. K. Arnold on the occasion of his 65th birthday.     

FeS2 nanosheets–luminol–O2 chemiluminescence method for determination of venlafaxine hydrochloride,imipramine hydrochloride,and cefazolin sodium

This study introduces a novel chemiluminescence (CL) approach utilizing FeS₂ nanosheets (NSs) catalyzed luminol–O₂ CL reaction for the measurement of three pharmaceuticals, namely venlafaxine hydrochloride (VFX), imipramine hydrochloride (IPM), and cefazolin sodium (CEF). The CL method involved the phenomenon of quenching induced by the pharmaceuticals in the CL reaction. To achieve the most quenching efficacy of the pharmaceuticals in the CL reaction, the concentrations of reactants comprising luminol, NaOH, and FeS₂ NSs were optimized accordingly. The calibration curves demonstrated exceptional linearity within the concentration range spanning from 4.00 × 10⁻⁷ to 1.00 × 10⁻³ mol L⁻¹, 1.00 × 10⁻⁷ to 1.00 × 10⁻⁴ mol L⁻¹, and 4.00 × 10⁻⁶ to 2.00 × 10⁻⁴ mol L⁻¹ with detection limits (3σ) of 3.54 × 10⁻⁷, 1.08 × 10⁻⁸, and 2.63 × 10⁻⁶ mol L⁻¹ for VFX, IPM, and CEF, respectively. This study synthesized FeS₂ NSs using a facile hydrothermal approach, and then the synthesized FeS₂ NSs were subjected to a comprehensive characterization using a range of spectroscopic methods. The proposed CL method was effective in measuring the aforementioned pharmaceuticals in pharmaceutical formulations as well as different water samples. The mechanism of the CL system has been elucidated.     

Intricacies of interactions,dynamics and solvent effects in enzyme catalysis: a computational perspective on cyclophilin A

The essential role of enzymes in biological processes has continually ignited sparks of interest in their mechanism of action. Fully understanding the mechanism of enzymes has broad implications in protein engineering and drug design. The more than five order of magnitude speed-up in the rate of peptidyl–prolyl cis–trans isomerisation by cyclophilin A (CypA) has been the target of intense research. CypA serves as a tractable model system, because it reversibly catalyses the rotation around peptidyl–prolyl bonds without any bond breakage or formation. Here, we discuss the results of recent computational approaches used to study the mechanism of CypA. We highlight the critical role of enzyme and substrate conformational dynamics in the developing interactions as the substrate approaches the transition state that results in an astonishing enhancement of isomerisation rate. The rate of isomerisation is affected by the intricate coupling between the dynamics of the substrate, enzyme and solvent. CypA binds its substrates via conformational selection, where rearrangements of key active site residues are necessary for substrate recognition. The conformational plasticity of the active site allows the enzyme to accommodate the most favourable interactions with the transition state that can be exploited for structure-based drug design.