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Ji Liu, Zhi Li
Alcohol dehydrogenase (ADH) and amine dehydrogenase (AmDH)-catalyzed one-pot cascade conversion of an alcohol to an amine provides a simple preparation of chiral amines. To enhance the cofactor recycling in this reaction, we report a new concept of coupling whole-cells with cell-free system to enable separated intra- and extra-cellular cofactor regeneration and recycling. This was demonstrated by the respective biotransformation of racemic 4-phenyl-2-butanol 1a and 1-phenyl-2-propanol 1b to (R)-4-phenylbutan-2-amine 3a and (R)-1-phenylpropan-2-amine 3b...
December 8, 2018: Biotechnology and Bioengineering
Qinghao Song, Zhen Li, Rouke Chen, Xiaopan Ma, Xiang Xiao, Jun Xu
The discovery of hyperthermophiles has dramatically changed our understanding of the habitats in which life can thrive. However, the extreme high temperatures in which these organisms live have severely restricted the development of genetic tools. The archaeon Pyrococcus yayanosii A1 is a strictly anaerobic and piezophilic hyperthermophile that is an ideal model for studies of extreme environmental adaptation. In the present study, we identified a high hydrostatic pressure (HHP)-inducible promoter (P hhp ) that controls target gene expression under HHP...
November 30, 2018: Applied and Environmental Microbiology
Lenka Lecová, Pavla Tůmová, Eva Nohýnková
The level of genetic variability of Giardia intestinalis clinical isolates is an intensively studied and discussed issue within the scientific community. Our collection of G. intestinalis human isolates includes six in vitro-cultured isolates from assemblage B, with extensive genetic variability. Such variability prevents the precise genotype characterisation by the multi-locus genotyping (MLG) method commonly used for assemblage A. It was speculated that the intra-assemblage variations represent a reciprocal genetic exchange or true mixed infection...
November 28, 2018: Parasitology Research
Duo Wu, Meng Feng, Zhi-Xin Wang, Ke Qiao, Hiroshi Tachibana, Xun-Jia Cheng
BACKGROUND: Acanthamoeba spp. can cause serious human infections, including Acanthamoeba keratitis, granulomatous amoebic encephalitis and cutaneous acanthamoebiasis. Cysteine biosynthesis and the L-serine metabolic pathway play important roles in the energy metabolism of Acanthamoeba spp. However, no study has confirmed the functions of cysteine synthase (AcCS) in the cysteine pathway and phosphoglycerate dehydrogenase (AcGDH) or phosphoserine aminotransferase (AcSPAT) in the non-phosphorylation serine metabolic pathway of Acanthamoeba...
November 26, 2018: Parasites & Vectors
Panpan Xie, Xiaoxue Zhou, Liangyu Zheng
Herein, three aldo/ketoreductases (AKRs) were obtained and used to prepare N- ethyl-methyl-carbamic acid-3-[(1S)-hydroxy-ethyl]-phenyl ester ((S)-NEMCA-HEPE), which is a key intermediate of (S)-Rivastigmine. To avoid the usage of extra cofactors, the recombinant whole-cells containing AKRs and glucose dehydrogenase (GDH) were constructed and applied in the reduction reaction. The excellent conversion of 83.3% and enantiomeric excess (e.e.p ) of 99.9% for (S)-NEMCA-HEPE was obtained when the recombinant whole cell (iolS-GDH) was selected as a catalyst...
November 20, 2018: Journal of Biotechnology
Guodong Chen, Xiaolong Li, Qian Chen, Li Wang, Kaijie Qi, Hao Yin, Xin Qiao, Peng Wang, Shaoling Zhang, Juyou Wu, Zhi Huang
Pear (Pyrus bretschneideri) is a popular fruit worldwide, but the irrational utilization of nitrogen as a fertilizer not only greatly affects the fruit' quality, but also wastes resources and results in serious environmental pollution. To better understand the molecular mechanism in pear responsible for the regulation of nitrate transport and assimilation, RNA-seq was performed on samples collected in response to nitrate treatments. Here, 10,273 differentially expressed genes were obtained and annotated into 49 GO terms, 45 clusters having co-expression trends that involved 18 KEGG-defined significantly overrepresented pathways...
December 2018: Plant Science: An International Journal of Experimental Plant Biology
Julia Origüen, María Ángeles Orellana, Mario Fernández-Ruiz, Laura Corbella, Rafael San Juan, María Ruiz-Ruigómez, Francisco López-Medrano, Manuel Lizasoain, Tamara Ruiz-Merlo, Guillermo Maestro-de la Calle, Patricia Parra, Jennifer Villa, Rafael Delgado, José María Aguado
Objectives: To evaluate the predictive value of PCR cycle threshold (Ct) for recurrence/severity, compared to toxin detection plus clinical variables. Methods: First episodes of CDI diagnosed during 2015 at our institution were included. Samples were tested for GDH and toxin A/B with a single EIA. Xpert® C. difficile PCR assay was performed to GDH positive samples. Medical data were reviewed by investigators blinded to diagnostic results to compare patients with/without recurrence or poor outcome (severe/severe-complicated CDI episode and all-cause death)...
November 21, 2018: Journal of Clinical Microbiology
Shuzhen Lv, Yun Tang, Kangyao Zhang, Dianping Tang
This work has looked to explore an innovative and powerful visible fluorescence immunoassay method through wet NH3 -triggered structural change of NH2 -MIL-125(Ti) impregnated on paper for the detection of carcinoembryonic antigen (CEA). Gold nanoparticles heavily functionalized with glutamate dehydrogenase (GDH) and secondary antibody were used for generation of wet NH3 with a sandwiched immunoassay format. Paper-based analytical device (PAD) coated with NH2 -MIL-125(Ti) exhibited good visible fluorescence intensity through wet NH3 -triggeried structural change with high accuracy and reproducibility...
November 26, 2018: Analytical Chemistry
Sina Rehbein, Christian Klotz, Ralf Ignatius, Elisabeth Müller, Anton Aebischer, Barbara Kohn
Giardia duodenalis is a relevant gastrointestinal protozoan pathogen of humans and animals. This species complex consists of eight genetically different assemblages. Assemblages A and B are pathogenic to humans and pets, thus confer zoonotic potential. The risk of zoonotic transmission has been controversially discussed. The aim of this monocentric cross-sectional pilot study was to investigate G. duodenalis assemblages in humans and pets living in common households in Berlin/Brandenburg (Germany). Samples from dogs, cats and humans sharing the same households were screened for Giardia infection by antigen-detecting assays...
November 20, 2018: Zoonoses and Public Health
Md Qumrul Hasan, Jonathan Yuen, Gymama Slaughter
Carbon nanotube (CNT)-cellulose pellicle was developed to create a conductive CNT network on 20 μm nanostructured cellulose film. The flexible and electrically conductive film was prepared by the modification of bacterial nanocellulose pellicle with multi-walled carbon nanotubes (MWCNTs). The composite film was further modified with redox enzymes including pyroquinoline quinone glucose dehydrogenase (PQQ-GDH) and bilirubin oxidase (BODx) functioning as the anodic and cathodic catalyst, respectively with glucose as the biofuel source...
July 2018: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
In Young Yoo, Dong Joon Song, Hee Jae Huh, Nam Yong Lee
Various commercial assays have recently been developed for detecting glutamate dehydrogenase (GDH) and/or toxin A/B to diagnose Clostridioides difficile infection (CDI). We compared the performance of two assays for the simultaneous detection of C. difficile GDH and toxin A/B, using 150 stool samples: C. DIFF QUIK CHEK COMPLETE (QCC; TechLab, Blacksburg, VA, USA) and RIDASCREEN Clostridium difficile GDH (RC-GDH) and Toxin A/B (RC-Toxin A/B; R-Biopharm, Darmstadt, Germany). For GDH detection, QCC and RC-GDH showed satisfactory sensitivity (95...
March 2019: Annals of Laboratory Medicine
Tanu Singhal, Sweta Shah, Reshma Tejam, Pooja Thakkar
Purpose: Clostridium difficile infection (CDI) is a serious healthcare-associated infection (HAI) now being increasingly reported from hospitals across India. However, there is a paucity of data on the incidence of and impact of control measures on CDI in India. Materials and Methods: This is a retrospective study conducted at a tertiary care hospital in Mumbai from January 2016 to December 2017. All patients with healthcare-onset diarrhoea were tested for C. difficile by glutamate dehydrogenase (GDH)/toxin assay or nucleic acid amplification test (NAAT)...
July 2018: Indian Journal of Medical Microbiology
Hayato Kimura, Ryutaro Asano, Natsumi Tsukamoto, Wakako Tsugawa, Koji Sode
Antibody-enzyme complexes (AECs) are ideal sensing elements, especially when oxidoreductases are used as the enzymes in the complex, with the potential to carry out rapid electrochemical measurements. However, conventional methods for the fabrication of AECs, including direct fusion and chemical conjugation, are associated with issues regarding the generation of insoluble aggregates and production of homogeneous AECs. Here, we developed a convenient and universal method for the fabrication of homogeneous AECs using the SpyCatcher/SpyTag system...
November 27, 2018: Analytical Chemistry
Fernando Pérez-García, João M P Jorge, Annika Dreyszas, Joe Max Risse, Volker F Wendisch
The dicarboxylic acid glutarate is an important building-block gaining interest in the chemical and pharmaceutical industry. Here, a synthetic pathway for fermentative production of glutarate by the actinobacterium Corynebacterium glutamicum has been developed. The pathway does not require molecular oxygen and operates via lysine decarboyxylase followed by two transamination and two NAD-dependent oxidation reactions. Using a genome-streamlined L-lysine producing strain as basis, metabolic engineering was performed to enable conversion of L-lysine to glutarate in a five-step synthetic pathway comprising lysine decarboxylase, putrescine transaminase and γ-aminobutyraldehyde dehydrogenase from Escherichia coli and GABA/5AVA amino transferase and succinate/glutarate semialdehyde dehydrogenase either from C...
2018: Frontiers in Microbiology
Andreas Stallmach, Philipp A Reuken, Niels Teich
Patients with chronic inflammatory bowel disease (IBD) have a significantly increased risk of clinically relevant clostridial infection (CDI). In turn, CDI can increase IBD activity. Therefore, rapid diagnosis and therapy is required. Many diagnostic and treatment studies on patients with CDI without inflammatory bowel disease are not congruent with IBD patients. This overview summarizes the everyday data of recent years and condenses these into four guiding principles. 1) patients with IBD present a risk population for a CDI...
November 2018: Zeitschrift Für Gastroenterologie
Shi-Chen Xie, Yang Zou, Dan Chen, Meng-Meng Jiang, Xiao-Dan Yuan, Zhao Li, Feng-Cai Zou, Jian-Fa Yang, Jin-Liang Sheng, Xing-Quan Zhu
Giardia duodenalis is an important zoonotic parasite which can parasitize in the intestines of humans and various animals. However, the information about the prevalence and genetic diversity of G. duodenalis in goats in China is limited. It is yet to be known whether Yunnan black goats, a unique goat breed in subtropical Yunnan province, southwestern China, are infected with G. duodenalis. Thus, a total of 907 fecal samples were collected from Yunnan black goats in five regions in Yunnan province, to estimate the prevalence and genotypes of G...
2018: BioMed Research International
P Mara, G S Fragiadakis, F Gkountromichos, D Alexandraki
Ammonium assimilation is linked to fundamental cellular processes that include the synthesis of non-essential amino acids like glutamate and glutamine. In Saccharomyces cerevisiae glutamate can be synthesized from α-ketoglutarate and ammonium through the action of NADP-dependent glutamate dehydrogenases Gdh1 and Gdh3. Gdh1 and Gdh3 are evolutionarily adapted isoforms and cover the anabolic role of the GDH-pathway. Here, we review the role and function of the GDH pathway in glutamate metabolism and we discuss the additional contributions of the pathway in chromatin regulation, nitrogen catabolite repression, ROS-mediated apoptosis, iron deficiency and sphingolipid-dependent actin cytoskeleton modulation in S...
November 1, 2018: Microbial Cell Factories
Claudia Sánchez, Myriam Consuelo López, Luis Alejandro Galeano, Yvonne Qvarnstrom, Katelyn Houghton, Juan David Ramírez
BACKGROUND: Protozoan parasites such as Giardia duodenalis, Cryptosporidium spp., Cyclospora cayetanensis, Toxoplasma gondii and Entamoeba histolytica represent a great challenge to the systems producing water for human consumption because their cystic forms are persistent in the environment and resist to the disinfection methods conventionally used for their control. In this study, we investigated the presence of these protozoan pathogens in both raw and treated water samples used for the production of drinking water in Nariño Department, southwest Colombia...
October 26, 2018: Parasites & Vectors
Omneya M Nassar, Changhong Li, Charles A Stanley, B Montgomery Pettitt, Thomas J Smith
Mammalian glutamate dehydrogenase (GDH) has complex allosteric regulation that is essential for a number of essential pathways (21). In particular, the loss of GTP inhibition causes the hyperinsulinism/hyperammonemia syndrome (HHS) where insulin is hypersecreted upon consumption of protein. The archetypical HHS lesion is H454Y and lies in the GTP binding pocket. To better understand the mechanism of HHS, we determined the crystal structure of this mutant. The mutation effects are limited to the H454Y GTP contacts...
October 27, 2018: Proteins
Adhish S Walvekar, Rajalakshmi Srinivasan, Ritu Gupta, Sunil Laxman
Methionine availability during overall amino acid limitation metabolically reprograms cells to support proliferation, the underlying basis for which remains unclear. Here, we construct the organization of this methionine mediated anabolic program, using yeast. Combining comparative transcriptome analysis, biochemical and metabolic flux based approaches, we discover that methionine rewires overall metabolic outputs by increasing the activity of a key regulatory node. This comprises of: the pentose phosphate pathway (PPP) coupled with reductive biosynthesis, the glutamate dehydrogenase (GDH) dependent synthesis of glutamate/glutamine, and pyridoxal-5-phosphate (PLP) dependent transamination capacity...
October 24, 2018: Molecular Biology of the Cell
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