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Martin Gustavsson, David Hörnström, Susanna Lundh, Jaroslav Belotserkovsky, Gen Larsson
Today, it is considered state-of-the-art to engineer living organisms for various biotechnology applications. Even though this has led to numerous scientific breakthroughs, the enclosed interior of bacterial cells still restricts interactions with enzymes, pathways and products due to the mass-transfer barrier formed by the cell envelope. To promote accessibility, we propose engineering of biocatalytic reactions and subsequent product deposition directly on the bacterial surface. As a proof-of-concept, we used the AIDA autotransporter vehicle for Escherichia coli surface expression of tyrosinase and fully oxidized externally added tyrosine to the biopolymer melanin...
October 26, 2016: Scientific Reports
Mariusz Mojzych, Paweł Tarasiuk, Katarzyna Kotwica-Mojzych, Muhammad Rafiq, Sung-Yum Seo, Michał Nicewicz, Emilia Fornal
A new series of sulfonamide derivatives of pyrazolo[4,3-e][1,2,4]triazine with chiral amino group has been synthesized and characterized. The compounds were tested for their tyrosinase and urease inhibitory activity. Evaluation of prepared derivatives demonstrated that compounds (8b) and (8j) are most potent mushroom tyrosinase inhibitors whereas all of the obtained compounds showed higher urease inhibitory activity than the standard thiourea. The compounds (8a), (8f) and (8i) exhibited excellent enzyme inhibitory activity with IC50 0...
October 25, 2016: Journal of Enzyme Inhibition and Medicinal Chemistry
Jang Hoon Kim, Ju-Yeon Yoon, Seo Young Yang, Seung-Kook Choi, Sun Jung Kwon, In Sook Cho, Min Hee Jeong, Young Ho Kim, Gug Seoun Choi
A new compound, 9-dihydroxyl-2'-O-(Z)-cinnamoyl-7-methoxy-aloesin (1), and eight known compounds (2-9) were isolated from Aloe vera. Their structures were elucidated using 1D/2D nuclear magnetic resonance and mass spectra. Compound 9 exhibited reversible competitive inhibitory activity against the enzyme tyrosinase, with an IC50 value of 9.8 ± 0.9 µM. A molecular simulation revealed that compound 9 interacts via hydrogen bonding with residues His244, Thr261, and Val283 of tyrosinase. Additionally, compounds 3 and 7 were shown by half-leaf assays to exhibit inhibitory activity towards Pepper mild mottle virus...
October 25, 2016: Journal of Enzyme Inhibition and Medicinal Chemistry
Monika B Dolinska, Nicole Kus, Katie Farney, Paul T Wingfield, Brian P Brooks, Yuri V Sergeev
: Oculocutaneous albinism Type 1 (OCA1) is an autosomal recessive disorder caused by mutations in the tyrosinase gene. Two subtypes of OCA1 have been described: severe OCA1A with complete absence of tyrosinase activity and less severe OCA1B with residual tyrosinase activity. Here, we characterize the recombinant human tyrosinase intra-melanosomal domain and mutant variants, which mimic genetic changes in both subtypes of OCA1 patients. Proteins were prepared using site-directed mutagenesis, expressed in insect larvae, purified by chromatography, and characterized by enzymatic activities- tryptophan fluorescence, and Gibbs free energy changes...
October 24, 2016: Pigment Cell & Melanoma Research
Xiaofeng Wu, Lihong Li, Wen Shi, Qiuyu Gong, Huimin Ma
Fluorescence imaging of tyrosinase (a cancer biomarker) in living organisms is of great importance for biological studies. However, selective detection of tyrosinase remains a great challenge because current fluorescent probes that contain the 4-hydroxyphenyl moiety show similar fluorescence responses to both tyrosinase and some reactive oxygen species (ROS), thereby suffering from ROS interference. Herein, a new tyrosinase-recognition 3-hydroxybenzyloxy moiety, which exhibits distinct fluorescence responses for tyrosinase and ROS, is proposed...
October 24, 2016: Angewandte Chemie
Guillermo Cásedas, Francisco Les, Maria Pilar Gómez-Serranillos, Carine Smith, Víctor López
Sour cherry juice (Prunus cerasus) is consumed as a nutritional supplement claiming health effects. The aim of the study was to evaluate the different properties of sour cherry juice in terms of antioxidant activity and inhibition of target enzymes in the central nervous system and diabetes. The content of polyphenols and anthocyanins was quantified. Different experiments were carried out to determine the radical scavenging properties of the juice. The activity of sour cherry juice was also tested in physiological relevant enzymes of the central nervous system (acetylcholinesterase, monoamine oxidase A, tyrosinase) and others involved in type 2 diabetes (α-glucosidase, dipeptidyl peptidase-4)...
October 24, 2016: Food & Function
Lijun Sun, Jingying Sun, Xueping Huo, Yaping Li, Yuan Li, Xin Xie, Jun Hu
Objective To explore the effect of Toll-like receptor 4 (TLR4) activation on melanogenesis in melanocytes. Methods The primary melanocytes were isolated, cultured and then stimulated by TLR4 agonist lipopolysaccharide (LPS). Firstly, the melanin content changes were detected in melanocytes, and then quantitative real-time PCR and Western blotting were employed to determine the expression levels of pre-melanosomal protein (Pmel17), tyrosinase (TYR) and microphthalmia-associated transcription factor (MITF). Finally, the melanosomes were observed by electron microscopy...
November 2016: Xi Bao Yu Fen Zi Mian Yi Xue za Zhi, Chinese Journal of Cellular and Molecular Immunology
Marcello Locatelli, Gokhan Zengin, Ahmet Uysal, Simone Carradori, Elisa De Luca, Giuseppe Bellagamba, Abdurrahman Aktumsek, Irina Lazarova
The current study was carried out to evaluate multicomponent pattern, biological and enzymatic activities of seven Asphodeline taxa root extracts as useful ingredients, due to the fact that these plants are commonly used as traditional food supplements in Turkish regions. The extracts were characterized for free anthraquinones and phenolics to obtain a specific chemical fingerprint useful for quality control. These analyzes were coupled to biological and enzymatic activities in order to obtain comprehensive information of the natural product...
October 24, 2016: Journal of Enzyme Inhibition and Medicinal Chemistry
Kourosh Abdollahi, Farshad Yazdani, Reza Panahi
Magnetic nanoparticles (MNPs) were synthesized using the chemical co-precipitation method. Then the nanoparticles were coated with silica via hydrolysis of tetraethyl orthosilicate using the sol-gel process. The silica coated magnetic nanoparticles were amine-functionalized with 3-aminopropyltriethoxysilane/ethanol solution. Subsequently, the nanoparticles were added to a solution of cyanuric chloride in tetrahydrofuran to synthesize cyanuric chloride-functionalized magnetic nanoparticles (Cy-MNPs). For covalent immobilization of tyrosinase, Cy-MNPs were added to a freshly prepared tyrosinase solution and the mixture was shaken...
October 19, 2016: International Journal of Biological Macromolecules
Hung-Yi Liu, Tanja Greene, Tsai-Yu Lin, Camron S Dawes, Murray Korc, Chien-Chi Lin
: The complex network of biochemical and biophysical cues in the pancreatic desmoplasia not only presents challenges to the fundamental understanding of tumor progression, but also hinders the development of therapeutic strategies against pancreatic cancer. Residing in the desmoplasia, pancreatic stellate cells (PSCs) are the major stromal cells affecting the growth and metastasis of pancreatic cancer cells by means of paracrine effects and extracellular matrix protein deposition. PSCs remain in a quiescent/dormant state until they are 'activated' by various environmental cues...
October 18, 2016: Acta Biomaterialia
Yoshiaki Manse, Kiyofumi Ninomiya, Ryosuke Nishi, Iyori Kamei, Yushi Katsuyama, Takahito Imagawa, Saowanee Chaipech, Osamu Muraoka, Toshio Morikawa
An aqueous acetone extract from the fruit of Alpinia galanga (Zingiberaceae) demonstrated inhibitory effects on melanogenesis in theophylline-stimulated murine B16 melanoma 4A5 cells (IC50=7.3μg/mL). Through bioassay-guided separation of the extract, a new 7-O-9'-linked neolignan, named galanganol D diacetate (1), was isolated along with 16 known compounds including 14 phenylpropanoids (2-15). The structure of 1, including its absolute stereochemistry in the C-7 position, was elucidated by means of extensive NMR analysis and total synthesis...
October 6, 2016: Bioorganic & Medicinal Chemistry
Daisuke Uesugi, Hiroki Hamada, Kei Shimoda, Naoji Kubota, Shin-Ichi Ozaki, Naoki Nagatani
The stilbene compound resveratrol was glycosylated to give its 4'-O-β-D-glucoside as the major product in addition to its 3-O-β-D-glucoside by a plant glucosyltransferase from Phytolacca americana expressed in recombinant Escherichia coli. This enzyme transformed pterostilbene to its 4'-O-β-D-glucoside, and converted pinostilbene to its 4'-O-β-D-glucoside as a major product and its 3-O-β-D-glucoside as a minor product. An analysis of antioxidant capacity showed that the above stilbene glycosides had lower oxygen radical absorbance capacity (ORAC) values than those of the corresponding stilbene aglycones...
October 19, 2016: Bioscience, Biotechnology, and Biochemistry
Oludemi Taofiq, Sandrina A Heleno, Ricardo C Calhelha, Maria José Alves, Lillian Barros, Maria Filomena Barreiro, Ana M González-Paramás, Isabel C F R Ferreira
The cosmetic industry is in a constant search for natural compounds or extracts with relevant bioactive properties, which became valuable ingredients to design cosmeceutical formulations. Mushrooms have been markedly studied in terms of nutritional value and medicinal properties. However, there is still slow progress in the biotechnological application of mushroom extracts in cosmetic formulations, either as antioxidants, anti-aging, antimicrobial, and anti-inflammatory agents or as hyperpigmentation correctors...
October 14, 2016: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Pravin Kesarwani, Paramita Chakraborty, Radhika Gudi, Shilpak Chatterjee, Gina Scurti, Kyle Toth, Patt Simms, Mahvash Husain, Kent Armeson, Shahid Husain, Elizabeth Garrett-Mayer, Chethamarakshan Vasu, Michael I Nishimura, Shikhar Mehrotra
Advancements in adoptive cell transfer therapy (ACT) has led to the use of T cells engineered with tumor specific T cell receptors, which after rapid expansion can be obtained in sufficient numbers for treating patients. However, due to massive proliferation these cells are close to replicative senescence, exhibit exhausted phenotype, and also display increased susceptibility to activation induced cell death. We have previously shown that tumor reactive T cells undergo caspase-independent cell death upon TCR restimulation with cognate antigen, which involves reactive oxygen species and c-jun N-terminal kinase...
October 14, 2016: Oncotarget
Zahra Boghrati, Maryam Naseri, Mitra Rezaie, Ngoc Pham, Ronald J Quinn, Zahra Tayarani-Najaran, Mehrdad Iranshahi
OBJECTIVES: In food industry, the inhibition of tyrosinase is very important, because this enzyme catalyzes the oxidation of phenolic compounds found in fruits and vegetables into quinones, which contribute in undesirable color and taste of fruits and vegetables. Teucrium polium L. var. gnaphalodes (Lamiaceae), a wild-growing flowering plant that has many applications in food preparations and traditional medicine. In Persian language, this medicinal herb is called Kalpoureh. MATERIALS AND METHODS: 1D- and 2D-NMR experiments were used to determine the chemical structures of the isolated compounds...
August 2016: Iranian Journal of Basic Medical Sciences
Birendra Kumar Singh, Seok Hoon Park, Hyang-Bok Lee, Young-Aae Goo, Hyoung Shik Kim, Seung Hee Cho, Jeong Hun Lee, Ghe Whan Ahn, Jin Pyo Kim, Su Myoung Kang, Eun-Ki Kim
BACKGROUND: Kojic acid was used for decades in the cosmetic industry as an antimelanogenic agent. However, there are two major drawbacks of Kojic acid, one is cytotoxicity and second are instability on storage. These limitations led the scientist to synthesize the active Kojic acid peptides. OBJECTIVE: In the present study, we synthesize and investigate the effect of five Kojic acid peptides to overcome the limitation of Kojic acid. METHODS: The peptide was analyzed and purified by high-performance liquid chromatography and matrix-assisted laser desorption ionization time of flight mass spectroscopy...
October 2016: Annals of Dermatology
Pham Thi Be Tu, Binh Cao Quan Nguyen, Shinkichi Tawata, Cheong-Yong Yun, Eung Gook Kim, Hiroshi Maruta
We previously demonstrated that the oncogenic kinase PAK4, which both melanomas and normal melanocytes express at a very high level, is essential for their melanogenesis. In the present study, using the highly sensitive "Macaroni-Western" (IP-ATP-Glo) kinase assay, we investigated the melanogenic potential of another oncogenic kinase PAK1, which melanoma (B16F10) cells express only at a very minute level. After transfecting melanoma cells with PAK1-shRNA for silencing PAK1 gene, melanin content, tyrosinase activity, and kinase activity of PAK1 were compared between the wild-type and transfectants...
October 17, 2016: Drug Discoveries & Therapeutics
Faten K Abd El-Hady, Walid Fayad, Carmine Iodice, Zeinab A El-Shahid, Mohamed S Abdel-Aziz, Egle Crudele, Giuseppina Tommonaro
Marine organisms have been considered as the richest sources of novel bioactive metabolites, which can be used for pharmaceutical purposes. In the last years, the interest for marine microorganisms has grown for their enormous biodiversity and for the evidence that many novel compounds isolated from marine invertebrates are really synthesized by their associated bacteria. Nevertheless, the discovery of a chemical communication Quorum sensing (QS) between bacterial cells and between bacteria and host has gained the researchers to expand the aim of their study toward the role of bacteria associated with marine invertebrates, such as marine sponge...
October 14, 2016: Current Microbiology
Batel Deri, Margarita Kanteev, Mor Goldfeder, Daniel Lecina, Victor Guallar, Noam Adir, Ayelet Fishman
Tyrosinases are responsible for melanin formation in all life domains. Tyrosinase inhibitors are used for the prevention of severe skin diseases, in skin-whitening creams and to avoid fruit browning, however continued use of many such inhibitors is considered unsafe. In this study we provide conclusive evidence of the inhibition mechanism of two well studied tyrosinase inhibitors, KA (kojic acid) and HQ (hydroquinone), which are extensively used in hyperpigmentation treatment. KA is reported in the literature with contradicting inhibition mechanisms, while HQ is described as both a tyrosinase inhibitor and a substrate...
October 11, 2016: Scientific Reports
Annewieke J W Verloop, Jean-Paul Vincken, Harry Gruppen
Formation of black tea thearubigins involves at least two of the following oxidation steps: (i) oligomerization, (ii) rearrangement, (iii) hydroxylation. The first two are mainly catalysed by polyphenol oxidase(PPO), whereas the enzyme responsible for hydroxylation has not yet been identified. Two main oxidative activities, peroxidase(POD) and PPO, occur in tea leaves. POD was hypothesized to be responsible for hydroxylation. Model systems with horseradish POD and mushroom tyrosinase were used investigating hydroxylation of theaflavins(TF)...
October 10, 2016: Journal of Agricultural and Food Chemistry
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