Bovine serum albumin/gold nanoparticles as a drug delivery system for Curcumin: experimental and computational studies

Abstract

Communicated by Ramaswamy H. Sarma     

Characterisation of digestive protease in the rose sawfly,Arge rosae Linnaeus (Hymenoptera: Argidae)

Insect midgut proteases are excellent targets for insecticidal agents such as protease inhibitors. These inhibitors are used for producing transgenic plants, resistant to pests. For achieving this goal, it is necessary to find the nature of specific proteases and their properties for adopting possible pest management procedure. Therefore, characterisation of the enzymes in the gut of the rose sawfly, Arge rosae (Hymenoptera: Argidae), responsible for proteolysis, was performed using a range of synthetic substrates and specific inhibitors. The optimum conditions for general proteases and trypsin were achieved at pH 10. The highest activity for general proteases was obtained at a temperature of 45°C. The use of specific inhibitors and SDS-PAGE (sodium dodecyl sulfate polyacrylamide gel electrophoresis) provided evidence to suggest that most of the proteases belonged to the serine group because of high inhibitory effect of phenyl methane sulfonyl fluoride on total proteolytic activity. Also, inhibition assays and zymogram analysis showed that metalloproteases are present in A. rosae digestive system. These results indicated that A. rosae larvae mainly used serine proteases for protein digestion, with chymotrypsin as the dominant form. The kinetic parameters of trypsin-like proteases using N-benzoyl-dl-arg-p-nitroanilide as substrate indicated that the K _m and V _max values of trypsin in the gut of the fifth instar larvae were 730 ± 17.3 μM and 456 ± 13.85 nmol min^?1 mg^?1 protein, respectively.     

Protein partners in the life history of activated fibroblast growth factor receptors

Fibroblast growth factor receptors (FGFRs) are a family of four transmembrane (TM) receptor tyrosine kinases (RTKs) which bind to a large family of fibroblast growth factor (FGF) ligands with varying affinity and specificity. FGFR signaling regulates many physiological and pathological processes in development and tissue homeostasis. Understanding FGFR signaling processes requires the identification of partner proteins which regulate receptor function and biological outputs. In this study, we employ an epitope-tagged, covalently dimerized, and constitutively activated form of FGFR1 to identify potential protein partners by MS. By this approach, we sample candidate FGFR effectors throughout the life history of the receptor. Functional classification of the partners identified revealed specific subclasses involved in protein biosynthesis and folding; structural and regulatory components of the cytoskeleton; known signaling effectors and small GTPases implicated in endocytosis and vesicular trafficking. The kinase dependency of the interaction was determined for a subset of previously unrecognized partners by coimmunoprecipitation, Western blotting, and immunocytochemistry. From this group, the small GTPase Rab5 was selected for functional interrogation. We show that short hairpin (sh) RNA-mediated depletion of Rab5 attenuates the activation of the extracellular-regulated kinase (ERK) 1/2 pathway by FGFR signaling. The strategic approach adopted in this study has revealed bona fide novel effectors of the FGFR signaling pathway.     

Src kinase modulates the activation, transport and signalling dynamics of fibroblast growth factor receptors

The non-receptor tyrosine kinase Src is recruited to activated fibroblast growth factor receptor (FGFR) complexes through the adaptor protein factor receptor substrate 2 (FRS2). Here, we show that Src kinase activity has a crucial role in the regulation of FGFR1 signalling dynamics. Following receptor activation by ligand binding, activated Src is colocalized with activated FGFR1 at the plasma membrane. This localization requires both active Src and FGFR1 kinases, which are inter-dependent. Internalization of activated FGFR1 is associated with release from complexes containing activated Src. Src-mediated transport and subsequent activation of FGFR1 require both RhoB endosomes and an intact actin cytoskeleton. Chemical and genetic inhibition studies showed strikingly different requirements for Src family kinases in FGFR1-mediated signalling; activation of the phosphoinositide-3 kinase-Akt pathway is severely attenuated, whereas activation of the extracellular signal-regulated kinase pathway is delayed in its initial phase and fails to attenuate.     

Length scale parameter of single trabecula in cancellous bone

Biomechanics and Modeling in Mechanobiology - In this paper, the material length scale parameter of the modified couple stress theory for trabecular bones is studied. For this reason, experimental...     

Design,Synthesis, and Molecular Docking of Some Novel Tacrine Based Cyclopentapyranopyridine- and Tetrahydropyranoquinoline-Kojic Acid Derivatives as Anti-Acetylcholinesterase Agents

A novel series of tacrine based cyclopentapyranopyridine- and tetrahydropyranoquinoline-kojic acid derivatives were designed, synthesized, and evaluated as anti-cholinesterase agents. The chemical structures of all target compounds were characterized by ¹H-NMR, ¹³C-NMR, and elemental analyses. The synthesized compounds mostly inhibited acetylcholinesterase enzyme (AChE) with IC₅₀ values of 4.18–48.71 μM rather than butyrylcholinesterase enzyme (BChE) with IC₅₀ values of >100 μM. Among them, cyclopentapyranopyridine-kojic acid derivatives showed slightly better AChE inhibitory activity compared to tetrahydropyranoquinoline-kojic acid. The compound 10-amino-2-(hydroxymethyl)-11-(4-isopropylphenyl)-7,8,9,11-tetrahydro-4H-cyclopenta[b]pyrano[2′,3′ : 5,6]pyrano[3,2-e]pyridin-4-one ( 6f ) bearing 4-isopropylphenyl moiety and cyclopentane ring exhibited the highest anti-AChE activity with IC₅₀ value of 4.18 μM. The kinetic study indicated that the compound 6f acts as a mixed inhibitor and the molecular docking studies also illustrated that the compound 6f binds to both the catalytic site (CS) and peripheral anionic site (PAS) of AChE. The compound 6f showed moderate neuroprotective properties against H₂O₂-induced cytotoxicity in PC12 cells. The theoretical ADME study also predicted good drug-likeness for the compound 6f . Based on these results, the compound 6f seems to be a very promising AChE inhibitor for the treatment of Alzheimer's disease.     

Synthesis of New Benzimidazole‐1,2,3‐triazole Hybrids as Tyrosinase Inhibitors

A novel series of benzimidazole‐1,2,3‐triazole hybrids containing substituted benzyl moieties were designed, synthesized and evaluated for their inhibitory activity against mushroom tyrosinase. The results indicated that 2‐(4‐{[1‐(3,4‐dichlorobenzyl)‐1H‐1,2,3‐triazol‐4‐yl]methoxy}phenyl)‐1H‐benzimidazole ( 6g ) and 2‐(4‐{[1‐(4‐bromobenzyl)‐1H‐1,2,3‐triazol‐4‐yl]methoxy}phenyl)‐1H‐benzimidazole ( 6h ) exhibited effective inhibitory activity with IC₅₀ values of 9.42 and 10.34 μm , respectively, comparable to that of kojic acid as the reference drug (IC₅₀ = 9.28 μm ). Kinetic study of compound 6g confirmed mixed‐type inhibitory activity towards tyrosinase indicating that it can bind to free enzyme as well as enzyme‐substrate complex. Also, molecular docking analysis was performed to determine the binding mode of the most potent compounds ( 6g and 6h ) in the active site of tyrosinase. Consequently, 6g and 6h derivatives might serve as promising candidates in cosmetics, medicine or food industry, and development of such compounds may be of an interest.