scholarly journals Biosynthesis of l-Sorbose and l-Psicose Based on C—C Bond Formation Catalyzed by Aldolases in an Engineered Corynebacterium glutamicum Strain

2015 ◽  
Vol 81 (13) ◽  
pp. 4284-4294 ◽  
Author(s):  
Jiangang Yang ◽  
Jitao Li ◽  
Yan Men ◽  
Yueming Zhu ◽  
Ying Zhang ◽  
...  
Keyword(s):  
Corynebacterium Glutamicum ◽  
Host Cells ◽  
Dihydroxyacetone Phosphate ◽  
Microbial Fermentation ◽  
One Pot ◽  
Content Type ◽  
Stereochemical Control ◽  
Fed Batch Culture ◽  
Fermentation Strategy ◽  
First Time

ABSTRACTThe property of loose stereochemical control at aldol products from aldolases helped to synthesize multiple polyhydroxylated compounds with nonnatural stereoconfiguration. In this study, we discovered for the first time that some fructose 1,6-diphosphate aldolases (FruA) and tagatose 1,6-diphosphate (TagA) aldolases lost their strict stereoselectivity when usingl-glyceraldehyde and synthesized not onlyl-sorbose but also a high proportion ofl-psicose. Among the aldolases tested, TagA fromBacillus licheniformis(BGatY) showed the highest enzyme activity withl-glyceraldehyde. Subsequently, a “one-pot” reaction based on BGatY and fructose-1-phosphatase (YqaB) generated 378 mg/literl-psicose and 199 mg/literl-sorbose from dihydroxyacetone-phosphate (DHAP) andl-glyceraldehyde. Because of the high cost and instability of DHAP, a microbial fermentation strategy was used further to producel-sorbose/l-psicose from glucose andl-glyceraldehyde, in which DHAP was obtained from glucose through the glycolytic pathway, and some recombination pathways based on FruA or TagA and YqaB were constructed inEscherichia coliandCorynebacterium glutamicumstrains. After evaluation of different host cells and combinations of FruA or TagA with YqaB and optimization of gene expression, recombinantC. glutamicumstrain WT(pXFTY) was selected and produced 2.53 g/liter total ketoses, with a yield of 0.50 g/gl-glyceraldehyde. Moreover, deletion of genecgl0331, encoding the Zn-dependent alcohol dehydrogenase inC. glutamicum, was confirmed for the first time to significantly decrease conversion ofl-glyceraldehyde to glycerol and to increase yield of target products. Finally, fed-batch culture of strain SY14(pXFTY) produced 3.5 g/literl-sorbose and 2.3 g/literl-psicose, with a yield of 0.61 g/gl-glyceraldehyde. This microbial fermentation strategy also could be applied to efficiently synthesize otherl-sugars.

scholarly journals Spiroplasma eriocheiris Enters Drosophila Schneider 2 Cells and Relies on Clathrin-Mediated Endocytosis and Macropinocytosis

2019 ◽  
Vol 87 (11) ◽  
Author(s):  
Panpan Wei ◽  
Mingxiao Ning ◽  
Meijun Yuan ◽  
Xiangqian Li ◽  
Hao Shi ◽  
...  
Keyword(s):  
Cell Model ◽  
Endocytic Pathway ◽  
Host Cells ◽  
Economic Losses ◽  
S2 Cells ◽  
Content Type ◽  
Kinase C ◽  
Apoptosis And Necrosis ◽  
First Time ◽  
Typical Inclusion

ABSTRACT Spiroplasma eriocheiris causes great economic losses in the crustacean aquaculture industry. However, the mechanism of S. eriocheiris infecting host cells has been poorly studied. We established a Spiroplasma-infected Drosophila Schneider 2 (S2) cell model and investigated its pathogenic mechanism. First, S. eriocheiris induced S2 cell apoptosis and necrosis, seriously decreased cell viability, and increased the production of intracellular reactive oxygen species. Further research showed that S. eriocheiris can invade S2 cells, and the number of copies of intracellular spiroplasmas is sharply increased by 12 h postinfection. In addition, S. eriocheiris can cause S2 cells to form typical inclusion bodies and exhibit large vacuoles. Second, S. eriocheiris is internalized into S2 cells and strongly inhibited through blocking clathrin-mediated endocytosis using chlorpromazine and dynasore. Inhibitors of macropinocytosis, protein kinase C and myosin II, cause a significant reduction in S. eriocheiris in S2 cells. In contrast, disruption of cellular cholesterol by methyl-β-cyclodextrin and nystatin has no effect on S. eriocheiris infection. These results suggest that the entry of S. eriocheiris into S2 cells relies on clathrin-dependent endocytosis and macropinocytosis, but not via the caveola-mediated endocytic pathway. In addition, the intracellular numbers of S. eriocheiris are dramatically reduced after S2 cells are treated with cytoskeleton-depolymerizing agents, including nocodazole and cytochalasin B. Thus, cellular infection by S. eriocheiris is related to microtubules and actin filaments. This research successfully shows for the first time that S. eriocheiris can invade Drosophila S2 cells and provides a process for S. eriocheiris infection.

scholarly journals Gold Nanoparticle-Conjugated Cinnamic Acid Exhibits Antiacanthamoebic and Antibacterial Properties

2018 ◽  
Vol 62 (9) ◽  
Author(s):  
Ayaz Anwar ◽  
Ruqaiyyah Siddiqui ◽  
Muhammad Raza Shah ◽  
Naveed Ahmed Khan
Keyword(s):  
Host Cell ◽  
Cinnamic Acid ◽  
Antibacterial Properties ◽  
Acanthamoeba Castellanii ◽  
Host Cells ◽  
Cell Cytotoxicity ◽  
Content Type ◽  
Host Cell Death ◽  
Natural Organic Compound ◽  
First Time

ABSTRACT trans-Cinnamic acid (CA) is a natural organic compound. Using amoebicidal assays, for the first time we showed that CA affected the viability of the protist pathogen Acanthamoeba castellanii. Conjugation with gold nanoparticles (AuNPs) enhanced the antiamoebic effects of CA. CA-coated AuNPs (CA-AuNPs) also exhibited significant excystation and encystation activity, compared to CA and AuNPs alone. Pretreatment of amoebae with CA-AuNPs inhibited A. castellanii-mediated host cell cytotoxicity. Moreover, CA-AuNPs exhibited potent effects against methicillin-resistant Staphylococcus aureus and neuropathogenic Escherichia coli K1 and protected host cells against bacteria-mediated host cell death.

An Expeditious One-Pot Three-Component Synthesis of 4-Aryl-3,4-dihydrobenzo[g] quinoline-2,5,10(1H)-triones under Green Conditions

2020 ◽  
Vol 23 (23) ◽  
pp. 2626-2634
Author(s):  
Saiedeh Kamalifar ◽  
Hamzeh Kiyani
Keyword(s):  
Reaction Medium ◽  
Meldrum's Acid ◽  
Meldrum’S Acid ◽  
One Pot ◽  
One Pot Synthesis ◽  
Substituted Benzaldehydes ◽  
High Yields ◽  
First Time ◽  
Green Conditions

: An efficient and facial one-pot synthesis of 4-aryl-3,4-dihydrobenzo[g]quinoline- 2,5,10(1H)-triones was developed for the first time. The process proceeded via the three-component cyclocondensation of 2-amino-1,4-naphthoquinone with Meldrum’s acid and substituted benzaldehydes under green conditions. The fused 3,4-dihydropyridin-2(1H)- one-ring naphthoquinones have been synthesized with good to high yields in refluxing ethanol as a green reaction medium. This protocol is simple and effective as well as does not involve the assistance of the catalyst, additive, or hazardous solvents.

Conference report: innovation, interaction … and a lot of data: first time reflections on Internet Librarian International, UK 2018

2019 ◽  
Vol 36 (2) ◽  
pp. 21-22
Author(s):  
Ray Harper
Keyword(s):  
Best Practice ◽  
New Technologies ◽  
Conference Report ◽  
Library Services ◽  
New Techniques ◽  
Content Type ◽  
Making A Difference ◽  
Analyse Data ◽  
Physical Spaces ◽  
First Time

Purpose The purpose of this paper is to summarise a number of presentations at Day 1 of the Internet Librarian International conference, London, UK (16 October 2018). This was the 20th conference in the series, and the three key themes included were the next-gen library and librarian; understanding users, usage and user experience; and inclusion and inspiration: libraries making a difference. Design/methodology/approach This paper reports from the viewpoint of a first-time attendee of the conference. This summarises the main issues raised by each presentation and draws out the key learning points for practical situations. Findings The conference covered a variety of practical ways in which libraries can use technology to support users and make decisions about services. These include developing interactive physical spaces which include augmented reality; introducing “chat-bots” to support users; using new techniques to analyse data; and piloting new ways to engage users (such as coding clubs). A key theme was how we use and harness data in a way that is ethical, effective and relevant to library services. Originality/value This conference focussed on practical examples of how library and information services across sectors and countries are innovating in a period of huge change. The conference gave delegates numerous useful ideas and examples of best practice and demonstrated the strength of the profession in adapting to new technologies and developments.

Interest rate option hedging portfolios without bank account

2019 ◽  
Vol 37 (1) ◽  
pp. 134-142
Author(s):  
Alberto Bueno-Guerrero
Keyword(s):  
Design Methodology ◽  
Contingent Claim ◽  
Necessary And Sufficient Condition ◽  
Barrier Option ◽  
Bank Account ◽  
Content Type ◽  
Option Hedging ◽  
Hedging Portfolio ◽  
Necessary And Sufficient ◽  
First Time

Purpose This paper aims to study the conditions for the hedging portfolio of any contingent claim on bonds to have no bank account part. Design/methodology/approach Hedging and Malliavin calculus techniques recently developed under a stochastic string framework are applied. Findings A necessary and sufficient condition for the hedging portfolio to have no bank account part is found. This condition is applied to a barrier option, and an example of a contingent claim whose hedging portfolio has a bank account part different from zero is provided. Originality/value To the best of the authors’ knowledge, this is the first time that this issue has been addressed in the literature.

Amino- and sulfo-bifunctionalized hyper-crosslinked organic nanotube frameworks as efficient catalysts for one-pot cascade reactions

2019 ◽  
Vol 43 (5) ◽  
pp. 2269-2273 ◽  
Author(s):  
Guojie Meng ◽  
Shengguang Gao ◽  
Ying Liu ◽  
Li Zhang ◽  
Chunmei Song ◽  
...  
Keyword(s):  
Cascade Reactions ◽  
One Pot ◽  
First Time

The synthesis of amino- and sulfo-bifunctionalized hyper-crosslinked organic nanotube frameworks for one-pot cascade reactions was reported for the first time.

A “Learning from Action” workshop in Japan

2019 ◽  
Vol 40 (2) ◽  
pp. 77-83
Author(s):  
Robert Douglas Hinshelwood ◽  
Luca Mingarelli ◽  
Simona Masnata
Keyword(s):  
Far East ◽  
Opportunity To Learn ◽  
Content Type ◽  
Work Activities ◽  
Defensive Role ◽  
Feedback Data ◽  
Experiential Workshop ◽  
First Time ◽  
Practical Implications

Purpose Many people in severe mentally disturbed states do not use language or other symbolic media well or coherently. Therefore, the non-verbal medium needs to be understood by workers with such people. The “Learning from Action” experiential workshop was developed in order to provide an opportunity to learn about hidden messages in the relationships and roles occurring in activities. In August 2017, a workshop was run for the first time in Japan. The purpose of this paper is to report the experience and dynamics observed by the three consultants, who are here the authors of this paper. Design/methodology/approach After the workshop all the staff and members, including interpreters, were invited to give feedback. Findings Analysis of the feedback data showed certain important dynamics, concerning especially dependence, cultural defences and the defensive role of activity in a multicultural context. Research limitations/implications This is an initial experience to be followed up by later feedback and further workshops. Practical implications Workers awareness of non-verbal communication within the roles of work activities is a training possibility. It faces various resistances including the mental health assumptions of meaninglessness of any communication outside the verbal. Originality/value This is a method of training not widely used even in European countries, and is the first in a country in the far east.

Whirling in between the personal and the impersonal

2019 ◽  
Vol 25 (2) ◽  
pp. 257-284
Author(s):  
Armen E. Petrosyan
Keyword(s):  
Organization Theory ◽  
Conceptual Analysis ◽  
Essential Elements ◽  
Organizational Life ◽  
Critical Perspective ◽  
Content Type ◽  
Organizational Goals ◽  
Last Stage ◽  
First Time ◽  
Current Paradigm

Purpose The paper aims to present a systematic conceptual analysis of the problem of organizational goal and to reduce the insights into it provided by the main conceptions taken in their development from one to another, to break out of the ruling paradigm and outline a new solution. Design/methodology/approach The study has been carried out from the historical and critical perspective. Findings The paper discovers the logic of the evolution the approaches to organizational goals have undergone and portrays it in a matrix form in the heart of which is the “zigzag effect”: each posterior stage returns to the essential elements rejected by those preceding it, and the last stage, being diametrically opposite to the first, is, at that, as well as the latter, akin to the intermediate stages. The opportunities afforded by the current paradigm have been exhausted and it seems to run to an impasse. Instead, the author suggests a new frame of orientation: organizational goals are closely interknit with personal, but not reducible to them and bear fundamentally transpersonal character, while the mechanism of involving the preferences of individuals and groups in goal-setting is based on the self-contained interests of the organization they pertain to. Research limitations/implications The findings, conclusions and generalizations obtained can serve for a necessary ground to researchers getting deeper into the essence of what bonds organizational life and activity. Practical implications The material empowers practitioners to comprehend the difficulties of framing cohesive goal and find efficient ways to overcome them. It is of value also to the teachers seeking to present a more exact and elaborate view of teleological foundations of management and organization theory. Originality/value Both the conceptual analysis of the evolution of the approaches to organizational goals and the author’s exposition of its logic and vision of their nature are provided for the first time.

scholarly journals Metabolic Engineering of Corynebacterium glutamicum for Methanol Metabolism

2015 ◽  
Vol 81 (6) ◽  
pp. 2215-2225 ◽  
Author(s):  
Sabrina Witthoff ◽  
Katja Schmitz ◽  
Sebastian Niedenführ ◽  
Katharina Nöh ◽  
Stephan Noack ◽  
...  
Keyword(s):  
Corynebacterium Glutamicum ◽  
Biotechnological Production ◽  
Methanol Metabolism ◽  
Initial Oxidation ◽  
Content Type ◽  
Oxidation Of Methanol ◽  
Bacillus Methanolicus ◽  
Production Processes ◽  
Starting Point ◽  
Limited Application

ABSTRACTMethanol is already an important carbon feedstock in the chemical industry, but it has found only limited application in biotechnological production processes. This can be mostly attributed to the inability of most microbial platform organisms to utilize methanol as a carbon and energy source. With the aim to turn methanol into a suitable feedstock for microbial production processes, we engineered the industrially important but nonmethylotrophic bacteriumCorynebacterium glutamicumtoward the utilization of methanol as an auxiliary carbon source in a sugar-based medium. Initial oxidation of methanol to formaldehyde was achieved by heterologous expression of a methanol dehydrogenase fromBacillus methanolicus, whereas assimilation of formaldehyde was realized by implementing the two key enzymes of the ribulose monophosphate pathway ofBacillus subtilis: 3-hexulose-6-phosphate synthase and 6-phospho-3-hexuloisomerase. The recombinantC. glutamicumstrain showed an average methanol consumption rate of 1.7 ± 0.3 mM/h (mean ± standard deviation) in a glucose-methanol medium, and the culture grew to a higher cell density than in medium without methanol. In addition, [13C]methanol-labeling experiments revealed labeling fractions of 3 to 10% in the m + 1 mass isotopomers of various intracellular metabolites. In the background of aC. glutamicumΔaldΔadhEmutant being strongly impaired in its ability to oxidize formaldehyde to CO2, the m + 1 labeling of these intermediates was increased (8 to 25%), pointing toward higher formaldehyde assimilation capabilities of this strain. The engineeredC. glutamicumstrains represent a promising starting point for the development of sugar-based biotechnological production processes using methanol as an auxiliary substrate.

The drivers of corporate governance disclosure: the case of Nifty 500 Index

2018 ◽  
Vol 60 (2) ◽  
pp. 681-700 ◽  
Author(s):  
Androniki Katarachia ◽  
Electra Pitoska ◽  
Grigoris Giannarakis ◽  
Elpida Poutoglidou
Keyword(s):  
Corporate Governance ◽  
Financial Leverage ◽  
Policy Makers ◽  
Content Type ◽  
Explanatory Variables ◽  
Size Number ◽  
Governance Practices ◽  
Board Director ◽  
First Time ◽  
Governance Disclosure

Purpose Based on agency theory, the purpose of this paper is to investigate the determinants on the dissemination level of corporate governance disclosure (CGD). Design/methodology/approach The sample of the study incorporates listed companies in Nifty 500 Index for the period 2009-2014. The Governance Disclosure Score calculated by Bloomberg is used as a proxy for the dissemination level of corporate governance information. In total, eight explanatory variables are uses, namely, board’s size, number of board meetings, CEO duality, presence of women on the board, company’s size, financial performance, Tobin’s Q ratio and financial leverage. Findings The results of study suggest a need for improvement in CGDs by Indian companies, as they fail to comply the majority of the proposed disclosure items. Furthermore, it is revealed that the number of board director, the value of company, the financial leverage and the presence of women affect negatively the dissemination level of corporate governance information. While, the size of company is the only determinant that positively affects the extent of CGD. Practical implications The results are valuable because they reveal the attributes that determines which companies needs less or extra monitoring by shareholders and investors regarding the applied corporate governance practices. In addition, the study can be valuable to policy makers responsible for the regulation of company’s accountability in relation to corporate governance practices. Originality/value The study extents previous studies by incorporating for the first time Bloomberg’s rating approach regarding the dissemination level of CGD in Indian context.

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