Self-Assembled Short Peptide Nanostructures: ‘’Dipeptides’’

Dipeptides are short peptide molecules formed by the peptide bond between two amino acids, and they play significant roles in various biological processes (such as protein synthesis, nutrient absorption, cellular signaling, immune response). Short peptides have a prominent place in the design of self-assembling materials. In particular, dipeptides have gained considerable attention in the field of biotechnology as a type of self-organizing nanostructure due to their low cost, simplicity of synthesis, biocompatibility, and tunability of functionality. However, there is limited knowledge about peptide and protein-based nanostructures in the literature. Therefore, more information is needed on dipeptide nanostructures, especially in terms of their potential applications for biomedical purposes. This review focuses on dipeptide nanostructures, particularly their potential uses in biomedical applications, and provides a broader perspective on the advantages, challenges, synthesis, interactions, and applications of these nanostructures

N-acyl homoserine lactone molecules assisted quorum sensing: effects consequences and monitoring of bacteria talking in real life

Bacteria utilize small signal molecules to monitor population densities. Bacteria arrange gene regulation in a method called Quorum Sensing (QS). The most widespread signalling molecules are N-Acyl Homoserine Lactones (AHLs/HSLs) for Gram-negative bacteria communities. QS plays significant role in the organizing of the bacterial gene that adapts to harsh environmental conditions for bacteria. It is involved in the arrangement of duties, such as biofilm formation occurrence, virulence activity of bacteria, production of antibiotics, plasmid conjugal transfer incident, pigmentation phenomenon and production of exopolysaccharide (EPS). QS obviously impacts on human health, agriculture and environment. AHL-related QS researches have been extensively studied and understood in depth for cell to cell intercommunication channel in Gram-negative bacteria. It is understood that AHL-based QS research has been extensively studied for cell-to-cell communication in Gram-negative bacteria; hence, a comprehensive study of AHLs, which are bacterial signal molecules, is required. The purpose of this review is to examine the effects of QS-mediated AHLs in many areas by looking at them from a different perspectives, such as clinic samples, food industry, aquatic life and wastewater treatment system

“Lab-on-pol” colormatic sensor platforms: Melamine detection with color change on melamine imprinted membranes

There is an urgent need to improve a specific, equipment-free and user friendly technique for detecting melamine in food samples. Here, melamine imprinted polymeric membranes were synthesized, and tested for selectivity in aqueous solutions against cyromazine used as competitor agent, and real milk samples spiked with melamine. Scanning electron microscope, atomic force microscopy, energy-dispersive X-ray and optical profilometer devices were used for characterization. Fe+3 ions were used as marker to obtain color change based on melamine concentration. The color intensity on MIP membranes was monitored by means of a color analysis application (Image J software) via a smartphone. Some obtained results as fallows: Melamine binding to 3D cavities of membrane came true in about 20 min. The linear regression plot showed a correlation coefficient (R2) of 0.995 in the range of 10 μM-50 μM according to Beer Lambert's law. A low concentration of melamine, (e.g., 10 µM) was determined in raw milk. Melamine imprinted polymeric membranes showed 7.575 times more sensitivity for melamine than cyromazine. Limit of detection (LOD) and limit of quantification (LOQ) were computed as 9.9 µM and 30.2 µM, respectively. Here, a new kind of smart polymer was designed, and successfully applied for the easy, portable and on-site colorimetric analysis via imprinted polymers, and named as “lab-on-pol”system. HPLC analysis method was also used to validate this new analysis method

Inhibition of bacterial adhesion by epigallocatechin gallate attached polymeric membranes

Microbial adhesion and formation of biofilms cause a serious problem in several areas including but not limited to food spoilage, industrial corrosion and nosocomial infections. These microbial biofilms pose a serious threat to human health since microbial communities in the biofilm matrix are protected with exopolymeric substances and difficult to eradicate with antibiotics. Hence, the prevention of microbial adhesion followed by biofilm formation is one of the promising strategies to prevent these consequences. The attachment of antimicrobial agents, coatings of nanomaterials and synthesis of hybrid materials are widely used approach to develop surfaces having potential to hinder bacterial adhesion and biofilm formation. In this study, epigallocatechin gallate (EGCG) is attached on p(HEMA-co-GMA) membranes to prevent the bacterial colonization. The attachment of EGCG to membranes was proved by Fourier-transform infrared spectroscopy (FT-IR). The synthesized membrane showed porous structure (SEM), and desirable swelling degree, which are ideal when it comes to the application in biotechnology and biomedicine. Furthermore, EGCG attached membrane showed significant potential to prevent the microbial colonization on the surface. The obtained results suggest that EGCG attached polymer could be used as an alternative approach to prevent the microbial colonization on the biomedical surfaces, food processing equipment as well as development of microbial resistant food packaging systems

Anti-cancer activity of naringenin loaded smart polymeric nanoparticles in breast cancer

Breast cancer is the most common form of cancer among women worldwide, and approximately comprise 25% of all female malignancies. Naringenin (Nar) is a promising anticancer agent for breast cancer. However, its use as a therapeutic agent is limited due to its poor water solubility and bioavailability. The purpose of the present study is to prepare pH and thermo sensitive smart polymeric nanoparticles carrying naringenin (NarSPNPs) to improve bioavailability, and increase therapeutic efficacy against breast cancer. N-isopropylacrylamide and Vinyl imidazole were used as thermo and pH sensitive monomers, respectively. NarSPNPs were characterized using dynamic light scattering (DLS) analyses, SEM and FTIR for particle size and potential analysis, surface morphology and functional group determinations, respectively. Release profile and its effects on cell proliferation, apoptosis and cell cycle in breast cancer were also studied. Physicochemical characterization of newly prepared NarSPNPs, cytotoxicity, and IC50 assessments confirmed their stability and bioactivity as an anti-breast cancer agent with no toxicity against human epithelia cells. These findings together with flow cytometry analysis, revealed that apoptosis is the main mechanism underlying cell death after NarSPNPs treatment

A rational approach for 3D recognition and removal of L-asparagine via molecularly imprinted membranes

In this study, a L-asparagine (L-Asn) imprinted membranes (L-Asn-MIPs) were synthesized via molecular imprinting for selective and efficient removal of L-Asn. The L-Asn-MIP membrane was prepared by using acrylamide (AAm) and hydroxyethyl methacrylate (HEMA) as a functional monomer and a comonomer, respectively. The membrane was characterized by scanning electron microscopy (SEM) and Fourier Transform infrared spectroscopy (FTIR). The L-Asn adsorption capacity of the membrane was investigated in detail. The maximum L-Asn adsorption capacity was determined as 408.2 mg/g at pH: 7.2, 24 °C. Determination of L-Asn binding behaviors of L-Asn-MIPs also shown with Scatchard analyses. The effect of pH on L-Asn adsorption onto the membrane and also the selectivity and reusability of the L-Asn-MIPs for L-Asn adsorption were determined through L-asparaginase (L-ASNase) enzyme activity measurements. The selectivity of the membrane was investigated by using two different ternary mixtures; L-glycine (L-Gly)/L-histidine (L-His)/L-Asn and L-tyrosin (L-Tyr)/L-cystein(L-Cys)/L-Asn. The obtained results showed that the L-Asn-MIP membranes have a high selectivity towards L-Asn

Immobilization of Alpha-Amylase onto Ni2+ Attached Carbon Felt: Investigation of Kinetic Parameters from Potato Wastewater

α-amylase is an important enzyme for textile, food, paper, and the pharmaceutical industrial areas. In this study, Ni2+ attached carbon felt structures with nitrogen active site (Ni2+-N-ACF) are produced. The surface morphologies of the N-ACF and Ni2+-N-ACF are investigated by means of scanning electron microscopy (SEM) analysis. Ni2+ ions binding on the N-ACFs are determined by energy dispersive X-ray (EDX) analysis and a graphite furnace atomic absorption spectrometer (AAS). The effect of pH, ionic strength, initial α-amylase concentration, and temperature parameters is investigated for α-amylase immobilization on Ni2+-N-ACF structures. In addition, pH and temperature effect on the activities of the free and the immobilized amylase, kinetic parameters, storage, and operational stabilities are made. Lastly, starch degradation in potato waste water is tested on Ni2+-N-ACF. The obtained results show that α-amylase immobilized Ni2+-N-ACF can be used for starch degradation on an industrial scale

Preparation of a new chromatographic media and assessment of some kinetic and interaction parameters for lysozyme

WOS: 000459528600053Silica based SBA-15 nanoparticles functionalized with aminopropyl-trimethoxysilane (AP) groups were prepared, and then Cu2+ ions were decorated onto them via AP (Cu+2-SBA-15), and calculated by ICP-OES as 137.9 mg/g nanoparticles. The characterizations of SBA-15 and SBA-15-AP were examined by XRD, FTIR and BET analysis. Prepared Cu+2-SBA-15 nanoparticles were embedded into cryogel column (Cu+2-SBA-15 NEC) photographed by SEM, and tried to investigate some adsorption parameters against to lysozyme selected as model protein. Lysozyme adsorption studies were conducted in a continuous system. The maximum adsorption capacity (1275.2 mg/g particles) of Cu+2-SBA-15 nanoparticles was obtained at phosphate buffer of pH 7.0 with initial lysozyme concentration of 1 mg/mL. According to examined Langmuir and Freundlich adsorption isotherms, Langmuir isotherm was fitted the best to this study. Composite cryogels were also used for 30 times in adsorption-desorption experiments. Purification capability of matrix was expressed as 88.5% with 913 purification yield from hen egg white (HEW) by means of SDS-PAGE. (C) 2018 Elsevier B.V. All rights reserved

L-asparaginase immobilized p(HEMA-GMA) cryogels: A recent study for biochemical, thermodynamic and kinetic parameters

*Önal, Burcu ( Aksaray, Yazar ) *Odabaşı, Mehmet ( Aksaray, Yazar )Cryogels have recently been attracted intense attention as suitable carriers for enzyme immobilization. Herein, L-asparaginase was selected as the model enzyme due to its application such as pharmaceutical and food. Under optimum conditions, L-asparaginase was immobilized on poly (2-hydroxyethyl methacrylate-glycidyl methacrylate) cryogels with 68.8% of immobilization yield and 69.3% of activity recovery. The immobilized enzyme exhibited improved stability with respect to the soluble enzyme at extreme conditions, especially around acidic pH and high temperature. Also, the storage stability and reusability of the immobilized enzyme were found to be approximately 54% and 52% of the original activity after 28 days at room temperature and 10 cycles, respectively. The thermodynamic studies indicated that activation energy (E-a) of the free enzyme decreased from 13.08 to 10.97 kJ/mol, which means an increase in the thermostability of L-asparaginase. The Michaelis-Menten constants (K-m) of 2.04 and 1.67 mM, and the maximum reaction rates (V-max) of 170.0 and 115.0 mu M min(-1) were estimated for soluble and immobilized L-asparaginase, respectively. These findings demonstrated that the designed cryogels turn out to be a good carrier matrix for L-asparaginase immobilization with high catalytic efficiency and enhanced stability