scholarly journals The Putative Mevalonate Diphosphate Decarboxylase from Picrophilus torridus Is in Reality a Mevalonate-3-Kinase with High Potential for Bioproduction of Isobutene

2015 ◽  
Vol 81 (7) ◽  
pp. 2625-2634 ◽  
Author(s):  
Luca Rossoni ◽  
Stephen J. Hall ◽  
Graham Eastham ◽  
Peter Licence ◽  
Gill Stephens
Keyword(s):  
Metabolic Pathways ◽  
The Novel ◽  
Detailed Characterization ◽  
Mva Pathway ◽  
Content Type ◽  
Mevalonate Diphosphate Decarboxylase ◽  
Picrophilus Torridus ◽  
Key Enzyme ◽  
Per Se ◽  
Putative Homologue

ABSTRACTMevalonate diphosphate decarboxylase (MVD) is an ATP-dependent enzyme that catalyzes the phosphorylation/decarboxylation of (R)-mevalonate-5-diphosphate to isopentenyl pyrophosphate in the mevalonate (MVA) pathway. MVD is a key enzyme in engineered metabolic pathways for bioproduction of isobutene, since it catalyzes the conversion of 3-hydroxyisovalerate (3-HIV) to isobutene, an important platform chemical. The putative homologue fromPicrophilus torridushas been identified as a highly efficient variant in a number of patents, but its detailed characterization has not been reported. In this study, we have successfully purified and characterized the putative MVD fromP. torridus.We discovered that it is not a decarboxylaseper sebut an ATP-dependent enzyme, mevalonate-3-kinase (M3K), which catalyzes the phosphorylation of MVA to mevalonate-3-phosphate. The enzyme's potential in isobutene formation is due to the conversion of 3-HIV to an unstable 3-phosphate intermediate that undergoes consequent spontaneous decarboxylation to form isobutene. Isobutene production rates were as high as 507 pmol min−1g cells−1usingEscherichia colicells expressing the enzyme and 2,880 pmol min−1mg protein−1with the purified histidine-tagged enzyme, significantly higher than reported previously. M3K is a key enzyme of the novel MVA pathway discovered very recently inThermoplasma acidophilum. We suggest thatP. torridusmetabolizes MVA by the same pathway.

scholarly journals Microbial Engineering for Aldehyde Synthesis

2015 ◽  
Vol 81 (6) ◽  
pp. 1892-1901 ◽  
Author(s):  
Aditya M. Kunjapur ◽  
Kristala L. J. Prather
Keyword(s):  
Escherichia Coli ◽  
Metabolic Pathways ◽  
De Novo ◽  
Attractive Alternative ◽  
Detailed Characterization ◽  
Content Type ◽  
E Coli ◽  
The Past ◽  
Alcohol Synthesis ◽  
Practical Limit

ABSTRACTAldehydes are a class of chemicals with many industrial uses. Several aldehydes are responsible for flavors and fragrances present in plants, but aldehydes are not known to accumulate in most natural microorganisms. In many cases, microbial production of aldehydes presents an attractive alternative to extraction from plants or chemical synthesis. During the past 2 decades, a variety of aldehyde biosynthetic enzymes have undergone detailed characterization. Although metabolic pathways that result in alcohol synthesis via aldehyde intermediates were long known, only recent investigations in model microbes such asEscherichia colihave succeeded in minimizing the rapid endogenous conversion of aldehydes into their corresponding alcohols. Such efforts have provided a foundation for microbial aldehyde synthesis and broader utilization of aldehydes as intermediates for other synthetically challenging biochemical classes. However, aldehyde toxicity imposes a practical limit on achievable aldehyde titers and remains an issue of academic and commercial interest. In this minireview, we summarize published efforts of microbial engineering for aldehyde synthesis, with an emphasis onde novosynthesis, engineered aldehyde accumulation inE. coli, and the challenge of aldehyde toxicity.

Responses of Arab teachers of Hebrew in Israel to an Israeli novel on Jewish-Arab relations

2019 ◽  
Vol 35 (2) ◽  
pp. 1-17
Author(s):  
Shai Rudin
Keyword(s):  
Boarding School ◽  
Educational Systems ◽  
The Novel ◽  
Content Type ◽  
Reading Experience ◽  
Political Views ◽  
Arab Students ◽  
Complex Integration ◽  
Education College ◽  
Arab Sector

Purpose This study aims to examine the responses and perceptions of Israeli Arab teachers toward multicultural and educational issues concerning Jewish–Arab relations. Design/methodology/approach This study is a qualitative research. The study included 44 novice Arab teachers, who teach Hebrew in the Arab sector and are currently studying toward their masters’ degree at a teacher education college in northern Israel. The teachers were asked to read the novel Nadia by Galila Ron Feder–Amit. Published in 1985, the novel describes the complex integration of Nadia, an Arab village girl, into a Jewish boarding school, and it is narrated in first person. After having read the novel, the teachers were requested to answer the writing task, which addressed the character of the protagonist, the issue of teaching the novel in the Jewish and Arabic educational systems and the anticipated responses of Jewish and Arab students to the novel. Findings Phenomenological analysis of the teachers’ responses found that the reading experience was complex and resulted in a variety of responses toward the protagonist. Some were based on identification and appreciation, while others on criticism and judgment of the heroine’s restraint vis-a-vis the racism that she was experiencing. However, most of the teachers demonstrated moral courage and thought that the novel should be taught, as they viewed it as a bridge leading to understanding between the two nations. The teachers anticipated conflicting responses of Jewish and Arab students to the novel, according to the students’ political views and values. Practical implications These findings indicate that the educational system should include political texts relating to the Jewish–Arab schism, especially texts that voice the Palestinian narrative. This view differs from the current situation in both sectors, whereby the tendency is to avoid political texts while ignoring the Palestinian narrative. Originality/value The study shows that the reading experience of a political novel affords various and often contrasting responses with the teachers facing the didactic challenges. The teachers who participated in the study anticipated complexity of the reading and teaching process, yet were not deterred by it, particularly in view of the novel’s messages – striving to understand the “other” and to bridge a discourse between the nations.

scholarly journals Novel Tandem Biotransformation Process for the Biosynthesis of a Novel Compound, 4-(2,3,5,6-Tetramethylpyrazine-1)-4′-Demethylepipodophyllotoxin

2011 ◽  
Vol 77 (9) ◽  
pp. 3023-3034 ◽  
Author(s):  
Ya-Jie Tang ◽  
Wei Zhao ◽  
Hong-Mei Li
Keyword(s):  
Cell Line ◽  
Alternaria Alternata ◽  
Water Solubility ◽  
Tumor Cell Line ◽  
Gibberella Fujikuroi ◽  
Hydroxyl Group ◽  
Epithelial Cell Line ◽  
The Novel ◽  
Content Type ◽  
Biotransformation Process

ABSTRACTAccording to the structure of podophyllotoxin and its structure-function relationship, a novel tandem biotransformation process was developed for the directional modification of the podophyllotoxin structure to directionally synthesize a novel compound, 4-(2,3,5,6-tetramethylpyrazine-1)-4′-demethylepipodophyllotoxin (4-TMP-DMEP). In this novel tandem biotransformation process, the starting substrate of podophyllotoxin was biotransformed into 4′-demethylepipodophyllotoxin (product 1) with the demethylation of the methoxyl group at the 4′ position byGibberella fujikuroiSH-f13, which was screened out from Shennongjia prime forest humus soil (Hubei, China). 4′-Demethylepipodophyllotoxin (product 1) was then biotransformed into 4′-demethylpodophyllotoxone (product 2) with the oxidation of the hydroxyl group at the 4 position byAlternaria alternataS-f6, which was screened out from the gatheredDysosma versipellisplants in the Wuhan Botanical Garden, Chinese Academy of Sciences. Finally, 4′-demethylpodophyllotoxone (product 2) and ligustrazine were linked with a transamination reaction to synthesize the target product 4-TMP-DMEP (product 3) byAlternaria alternataS-f6. Compared with podophyllotoxin (i.e., a 50% effective concentration [EC50] of 529 μM), the EC50of 4-TMP-DMEP against the tumor cell line BGC-823 (i.e., 0.11 μM) was significantly reduced by 5,199 times. Simultaneously, the EC50of 4-TMP-DMEP against the normal human proximal tubular epithelial cell line HK-2 (i.e., 0.40 μM) was 66 times higher than that of podophyllotoxin (i.e., 0.006 μM). Furthermore, compared with podophyllotoxin (i.e., logP= 0.34), the water solubility of 4-TMP-DMEP (i.e., logP= 0.66) was significantly enhanced by 94%. For the first time, the novel compound 4-TMP-DMEP with superior antitumor activity was directionally synthesized from podophyllotoxin by the novel tandem biotransformation process developed in this work.

scholarly journals The Novel Arylamidine T-2307 MaintainsIn VitroandIn VivoActivity against Echinocandin-Resistant Candida albicans

2014 ◽  
Vol 59 (2) ◽  
pp. 1341-1343 ◽  
Author(s):  
Nathan P. Wiederhold ◽  
Laura K. Najvar ◽  
Annette W. Fothergill ◽  
Rosie Bocanegra ◽  
Marcos Olivo ◽  
...  
Keyword(s):  
Body Weight ◽  
Candida Albicans ◽  
Invasive Candidiasis ◽  
Placebo Control ◽  
The Novel ◽  
Content Type ◽  
Fungal Burden ◽  
Potential Use

ABSTRACTWe evaluated thein vitroandin vivoactivities of the investigational arylamidine T-2307 against echinocandin-resistantCandida albicans. T-2307 demonstrated potentin vitroactivity, and daily subcutaneous doses between 0.75 and 6 mg/kg of body weight significantly improved survival and reduced fungal burden compared to placebo control and caspofungin (10 mg/kg/day) in mice with invasive candidiasis caused by an echinocandin-resistant strain. Thus, T-2307 may have potential use in the treatment of echinocandin-resistantC. albicansinfections.

scholarly journals Burkholderia insulsa sp. nov., a facultatively chemolithotrophic bacterium isolated from an arsenic-rich shallow marine hydrothermal system

2015 ◽  
Vol 65 (Pt_1) ◽  
pp. 189-194 ◽  
Author(s):  
Antje Rusch ◽  
Shaer Islam ◽  
Pratixa Savalia ◽  
Jan P. Amend
Keyword(s):  
Type Species ◽  
Sequence Similarity ◽  
Rrna Gene ◽  
The Novel ◽  
Carbohydrate Utilization ◽  
Content Type ◽  
Link Type ◽  
Optimum Ph ◽  
Shallow Marine Hydrothermal System ◽  
Type Strains

Enrichment cultures inoculated with hydrothermally influenced nearshore sediment from Papua New Guinea led to the isolation of an arsenic-tolerant, acidophilic, facultatively aerobic bacterial strain designated PNG-AprilT. Cells of this strain were Gram-stain-negative, rod-shaped, motile and did not form spores. Strain PNG-AprilT grew at temperatures between 4 °C and 40 °C (optimum 30–37 °C), at pH 3.5 to 8.3 (optimum pH 5–6) and in the presence of up to 2.7 % NaCl (optimum 0–1.0 %). Both arsenate and arsenite were tolerated up to concentrations of at least 0.5 mM. Metabolism in strain PNG-AprilT was strictly respiratory. Heterotrophic growth occurred with O2 or nitrate as electron acceptors, and aerobic lithoautotrophic growth was observed with thiosulfate or nitrite as electron donors. The novel isolate was capable of N2-fixation. The respiratory quinones were Q-8 and Q-7. Phylogenetically, strain PNG-AprilT belongs to the genus Burkholderia and shares the highest 16S rRNA gene sequence similarity with the type strains of Burkholderia fungorum (99.8 %), Burkholderia phytofirmans (98.8 %), Burkholderia caledonica (98.4 %) and Burkholderia sediminicola (98.4 %). Differences from these related species in several physiological characteristics (lipid composition, carbohydrate utilization, enzyme profiles) and DNA–DNA hybridization suggested the isolate represents a novel species of the genus Burkholderia , for which we propose the name Burkholderia insulsa sp. nov. The type strain is PNG-AprilT ( = DSM 28142T = LMG 28183T).

A novel fractional discrete grey model with an adaptive structure and its application in electricity consumption prediction

Kybernetes ◽  
2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yitong Liu ◽  
Yang Yang ◽  
Dingyu Xue ◽  
Feng Pan
Keyword(s):  
Fractional Order ◽  
Electricity Consumption ◽  
Grey Model ◽  
The Novel ◽  
Raw Data ◽  
Content Type ◽  
Power Load ◽  
Grey Models ◽  
Novel Model ◽  
Consumption Prediction

PurposeElectricity consumption prediction has been an important topic for its significant impact on electric policies. Due to various uncertain factors, the growth trends of electricity consumption in different cases are variable. However, the traditional grey model is based on a fixed structure which sometimes cannot match the trend of raw data. Consequently, the predictive accuracy is variable as cases change. To improve the model's adaptability and forecasting ability, a novel fractional discrete grey model with variable structure is proposed in this paper.Design/methodology/approachThe novel model can be regarded as a homogenous or non-homogenous exponent predicting model by changing the structure. And it selects the appropriate structure depending on the characteristics of raw data. The introduction of fractional accumulation enhances the predicting ability of the novel model. And the relative fractional order r is calculated by the numerical iterative algorithm which is simple but effective.FindingsTwo cases of power load and electricity consumption in Jiangsu and Fujian are applied to assess the predicting accuracy of the novel grey model. Four widely-used grey models, three classical statistical models and the multi-layer artificial neural network model are taken into comparison. The results demonstrate that the novel grey model performs well in all cases, and is superior to the comparative eight models.Originality/valueA fractional-order discrete grey model with an adaptable structure is proposed to solve the conflict between traditional grey models' fixed structures and variable development trends of raw data. In applications, the novel model has satisfied adaptability and predicting accuracy.

Survey on the dissemination of Web-based information on “evacuation and sheltering” in the context of COVID-19 by the Japanese Government

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Hiroaki Sano ◽  
Yohei Chiba ◽  
Sachiko Maeda ◽  
Chiharu Ikeda ◽  
Nobuyuki Handa ◽  
...  
Keyword(s):  
Design Methodology ◽  
Information Dissemination ◽  
Central Government ◽  
Health Centers ◽  
The Novel ◽  
Web Based ◽  
Content Type ◽  
Administrative Agencies ◽  
Novel Coronavirus ◽  
Actual Response

Purpose This study examines the websites of central government ministries, prefectures and municipalities to obtain a comprehensive bird’s-eye view of how they are preparing for natural disasters in the context of the novel coronavirus (COVID-19) outbreak. Design/methodology/approach This study examines the websites of central government ministries, prefectures and municipalities in Japan to survey the actual status of information dissemination on “evacuation and sheltering” in the context of COVID-19. Findings This study found that the central government issued many notices, notifications and administrative communications to prefectures, cities with public health centers and special wards, which were mainly related to opening, securing and operating evacuation centers and improving the environment. It was found that most prefectures disseminated information on both survival and living evacuation and did so from June onward, when the flood season was approaching. Among the municipalities, there were differences in information dissemination tendencies by prefecture, and it became clear that smaller municipalities were especially incapable of fully disseminating information via the Web. Research limitations/implications The data from the prefectures and municipalities surveyed in this study were collected from websites and do not necessarily represent the actual response to disaster-related evacuation in the context of COVID-19 in those areas. To clarify this evacuation, more detailed surveys are needed. Originality/value This study is unique because no research has been conducted on the response of Japanese administrative agencies to disaster-related evacuation in the context of COVID-19; the actual situation was analyzed in this study by examining central government ministries, prefectures and municipalities as administrative agencies and comparing their responses.

Volatility transmission across international markets amid COVID 19 pandemic

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Hechem Ajmi ◽  
Nadia Arfaoui ◽  
Karima Saci
Keyword(s):  
Crude Oil ◽  
International Markets ◽  
The Novel ◽  
Data Set ◽  
Health Crisis ◽  
Content Type ◽  
Volatility Transmission ◽  
Oil Markets ◽  
Novel Coronavirus ◽  
Death Cases

Purpose This paper aims to investigate the volatility transmission across stocks, gold and crude oil markets before and during the novel coronavirus (COVID-19) crisis. Design/methodology/approach A multivariate vector autoregression (VAR)-Baba, Engle, Kraft and Kroner generalized autoregressive conditional heteroskedasticity model (BEKK-GARCH) is used to assess volatility transmission across the examined markets. The sample is divided as follows. The first period ranging from 02/01/2019 to 10/03/2020 defines the pre-COVID-19 crisis. The second period is from 11/03/2020 to 05/10/2020, representing the COVID-19 crisis period. Then, a robustness test is used using exponential GARCH models after including an exogenous variable capturing the growth of COVID-19 confirmed death cases worldwide with the aim to test the accuracy of the VAR-BEKK-GARCH estimated results. Findings Results indicate that the interconnectedness among the examined market has been intensified during the COVID-19 crisis, proving the lack of hedging opportunities. It is also found that stocks and Gold markets lead the crude oil market especially during the COVID-19 crisis, which explains the freefall of the crude oil price during the health crisis. Similarly, results show that Gold is most likely to act as a diversifier rather than a hedging tool during the current health crisis. Originality/value Although the recent studies in the field focused on analyzing the relationships between different markets during the first quarter of 2020, this study considers a larger data set with the aim to assess the volatility transmission across the examined international markets Amid the COVID-19 crisis, while it shows the most significant impact on various financial markets compared to other diseases.

Place–brand stereotypes: does stereotype-consistent messaging matter?

2018 ◽  
Vol 27 (7) ◽  
pp. 754-767
Author(s):  
Brittney C. Bauer ◽  
Clark D. Johnson ◽  
Nitish Singh
Keyword(s):  
Mediating Effect ◽  
The Novel ◽  
Perceived Fit ◽  
Experimental Conditions ◽  
Content Type ◽  
Global Brands ◽  
Place Brand ◽  
Foreign Brands ◽  
Improve Attitude ◽  
Post Hoc

Purpose The purpose of this paper is to address an overarching question: Does matching consumer place–brand associations with stereotype-consistent messaging affect consumer perceptions of an advertisement? Design/methodology/approach This paper presents two experiments that examine participants’ differing evaluations of advertisements under various experimental conditions. Study 1 examines the match of place–brand warmth versus competence stereotypes and the use of symbolic versus utilitarian advertising messaging for both new foreign and domestic brands. Study 2 examines this match for global brands. Findings The paper reveals that stereotype-consistent messaging increases the perceived fit between the advertisement and the brand for new foreign brands but not for new domestic or global brands. Furthermore, in a post-hoc analysis, this congruence is found to improve attitude towards the brand, purchase intentions and brand response, through the mediating effect of attitude towards the ad. Originality/value Place–brand stereotypes impact consumer attitudes and opinions regarding brands from different countries. This paper applies two universal social judgment dimensions from social psychology—warmth and competence—to the novel context of advertising messaging to examine previously unexplored facets of the place–brand image.

Microwave synthesis, photophysical properties of novel fluorescent iminocoumarins and their application in textile printing

2015 ◽  
Vol 44 (2) ◽  
pp. 87-93 ◽  
Author(s):  
G.H. Elgemeie ◽  
K.A. Ahmed ◽  
E.A. ahmed ◽  
M.H. helal ◽  
D.M. Masoud
Keyword(s):  
Blue Light ◽  
Microwave Synthesis ◽  
Photophysical Properties ◽  
Ethyl Cyanoacetate ◽  
High Yield ◽  
The Novel ◽  
Dioxane Solution ◽  
Content Type ◽  
Textile Printing ◽  
Short Time

Purpose – This paper aims to synthesise coumarine flourescent dyes from a cheap material in a very short time with a very high yield, and by using a clean green chemistry. Design/methodology/approach – Efficient microwave synthesis for some novel iminocoumarins starts from the reaction of p-phenyl-enediamine and ethyl cyanoacetate followed by cyclocondensation with salicylaldehyde derivatives. Findings – The synthesized iminocoumarine compounds were characterized by spectroscopic methods. Absorption and fluorescence spectra of the compounds were also recorded. All compounds were fluorescent in 1,4-dioxane solution, they all emitted blue light (440-460 nm). The printing properties were studied, and their applications on printing polyester and polyamide fabrics were studied by silk screen printing. Originality/value – The authors designed efficient microwavel synthesis for some novel iminocoumarine derivatives; The novel procedure features short-reaction time, moderate yields and simple workup; All compounds were fluorescent in 1,4-dioxane solution, and they all emitted blue light; The authors studied their application in printing polyester and polyamide fabrics.

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