scholarly journals Biochemical Characteristics and Substrate Degradation Pattern of a Novel Exo-Type β-Agarase from the Polysaccharide-Degrading Marine Bacterium Flammeovirga sp. Strain MY04

2016 ◽  
Vol 82 (16) ◽  
pp. 4944-4954 ◽  
Author(s):  
Wenjun Han ◽  
Yuanyuan Cheng ◽  
Dandan Wang ◽  
Shumin Wang ◽  
Huihui Liu ◽  
...  
Keyword(s):  
Spectrum Analysis ◽  
Mass Spectrometry Analysis ◽  
Fluorescence Labeling ◽  
The Novel ◽  
Sugar Chain ◽  
Content Type ◽  
Glycosidic Bonds ◽  
Chain Analysis ◽  
Sequencing Method ◽  
Enzyme Cleavage

ABSTRACTExo-type agarases release disaccharide units (3,6-anhydro-l-galactopyranose-α-1,3-d-galactose) from the agarose chain and, in combination with endo-type agarases, play important roles in the processive degradation of agarose. Several exo-agarases have been identified. However, their substrate-degrading patterns and corresponding mechanisms are still unclear because of a lack of proper technologies for sugar chain analysis. Herein, we report the novel properties of AgaO, a disaccharide-producing agarase identified from the genusFlammeovirga. AgaO is a 705-amino-acid protein that is unique to strain MY04. It shares sequence identities of less than 40% with reported GH50 β-agarases. Recombinant AgaO (rAgaO) yields disaccharides as the sole final product when degrading agarose and associated oligosaccharides. Its smallest substrate is a neoagarotetraose, and its disaccharide/agarose conversion ratio is 0.5. Using fluorescence labeling and two-stage mass spectrometry analysis, we demonstrate that the disaccharide products are neoagarobiose products instead of agarobiose products, as verified by13C nuclear magnetic resonance spectrum analysis. Therefore, we provide a useful oligosaccharide sequencing method to determine the patterns of enzyme cleavage of glycosidic bonds. Moreover, AgaO produces neoagarobiose products by gradually cleaving the units from the nonreducing end of fluorescently labeled sugar chains, and so our method represents a novel biochemical visualization of the exolytic pattern of an agarase. Various truncated AgaO proteins lost their disaccharide-producing capabilities, indicating a strict structure-function relationship for the whole enzyme. This study provides insights into the novel catalytic mechanism and enzymatic properties of an exo-type β-agarase for the benefit of potential future applications.IMPORTANCEExo-type agarases can degrade agarose to yield disaccharides almost exclusively, and therefore, they are important tools for disaccharide preparation. However, their enzymatic mechanisms and agarose degradation patterns are still unclear due to the lack of proper technologies for sugar chain analysis. In this study, AgaO was identified as an exo-type agarase of agarose-degradingFlammeovirgabacteria, representing a novel branch of glycoside hydrolase family 50. Using fluorescence labeling, high-performance liquid chromatography, and mass spectrum analysis technologies, we provide a useful oligosaccharide sequencing method to determine the patterns of enzyme cleavage of glycosidic bonds. We also demonstrate that AgaO produces neoagarobiose by gradually cleaving disaccharides from the nonreducing end of fluorescently labeled sugars. This study will benefit future enzyme applications and oligosaccharide studies.

scholarly journals Coidentification of mcr-4.3 and blaNDM-1 in a Clinical Enterobacter cloacae Isolate from China

2018 ◽  
Vol 62 (10) ◽  
Author(s):  
Bhakti Chavda ◽  
Jingnan Lv ◽  
Mengyun Hou ◽  
Kalyan D. Chavda ◽  
Barry N. Kreiswirth ◽  
...  
Keyword(s):  
Lipid A ◽  
Susceptibility Testing ◽  
Enterobacter Cloacae ◽  
Mass Spectrometry Analysis ◽  
Ionization Mass ◽  
The Novel ◽  
Laser Desorption Ionization ◽  
Content Type ◽  
Spectrometry Analysis ◽  
High Level

ABSTRACT We describe the first report of a clinical colistin-resistant ST84 Enterobacter cloacae isolate coharboring mcr-4.3 (previously named mcr-4.2) and blaNDM-1 from a patient in China. The blaNDM-1-harboring IncX3 plasmid and the novel mcr-4.3-harboring ColE plasmid were completely sequenced. Although this isolate showed a high level of resistance to colistin, mcr-4.3 plasmid transformation, gene subcloning, susceptibility testing, and lipid A matrix-assisted laser desorption ionization mass spectrometry analysis indicated that mcr-4.3 itself does not confer resistance to colistin.

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.

Value chain analysis: an iterative and relational approach for agri-food chains

2016 ◽  
Vol 21 (3) ◽  
pp. 352-362 ◽  
Author(s):  
Janet Howieson ◽  
Meredith Lawley ◽  
Kathleen Hastings
Keyword(s):  
Diagnostic Tool ◽  
Value Chain ◽  
Positive Impact ◽  
Value Chains ◽  
Food Chains ◽  
Value Chain Analysis ◽  
Content Type ◽  
Relational Approach ◽  
Chain Analysis ◽  
Original Contribution

Purpose Value Chain Analysis (VCA) is established as a diagnostic tool. The purpose of this study is to extend existing applications and develop an iterative and relational method. to facilitate the application of VCA to agri-food chains as a strategic process rather than a diagnostic tool. Design/methodology/approach Using a multiple case study design, the new approach to VCA was applied to four Australian prawn fisheries. These fisheries varied in size, location, management structures and marketing arrangements and allowed the general applicability of the approach to be explored. Findings The application of the revised VCA revealed the importance of undertaking a strategic approach, with the outcome for all fisheries being a greater understanding of their consumers and an enhanced realisation of commercial opportunities. Two fisheries completed the revised VCA, and the findings show that a relational approach is crucial in creating value. In addition, it was shown that formalised structures and the informal behaviours of the value chain members have a strong positive impact on the relationship process. Research limitations/implications The research furthers the value chain literature and contributes an iterative approach to the application of VCA. The research also shows that obtaining improvements is not achievable for all chains, and, if the entire chain is not engaged with the process, the value of the results will be compromised. Further research is needed to confirm the validity of findings in other food industries. Originality/value The relational approach is an original contribution to the area of VCA research and provides industry with a blueprint for creating successful value chains. Specifically, the areas of implementation and evaluation make an original contribution to the theoretical and practical knowledge of value chains.

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 Comparative Efficacies of Artemisinin Combination Therapies in Plasmodium falciparum Malaria and Polymorphism ofpfATPase6,pfcrt,pfdhfr, andpfdhpsGenes in Tea Gardens of Jalpaiguri District, India

2012 ◽  
Vol 56 (5) ◽  
pp. 2511-2517 ◽  
Author(s):  
Pabitra Saha ◽  
Subhasish K. Guha ◽  
Sonali Das ◽  
Shrabanee Mullick ◽  
Swagata Ganguly ◽  
...  
Keyword(s):  
Plasmodium Falciparum Malaria ◽  
Study Groups ◽  
Combination Therapies ◽  
Antimalarial Drug Resistance ◽  
Content Type ◽  
Private Practitioners ◽  
Mutational Pattern ◽  
Sequencing Method ◽  
Periodic Monitoring ◽  
Artemisinin Combination Therapies

ABSTRACTIn India, chloroquine has been replaced by a combination of artesunate and sulfadoxine-pyrimethamine (AS-SP) for uncomplicatedP. falciparummalaria. Other available combinations, artemether-lumefantrine (AM-LF) and artesunate-mefloquine (AS-MQ), not included in the national program, are widely used by private practitioners. Little is known about the therapeutic efficacy of these artemisinin combinations and the prevalence of molecular markers associated with antimalarial drug resistance. A total of 157 patients withP. falciparummonoinfection were recruited and randomized into three study groups (AS-SP, AM-LF, and AS-MQ). All patients were followed up for 42 days to study the clinical and parasitological responses according to the WHO protocol (2009). We assessed the polymorphism of thepfATPase6,pfcrt,pfdhfr, andpfdhpsgenes by the DNA-sequencing method. The PCR-corrected therapeutic efficacies of AS-SP, AM-LF, and AS-MQ were 90.6% (95% confidence interval [CI], 0.793 to 0.969), 95.9% (95% CI, 0.860 to 0.995), and 100% (95% CI, 0.927 to 1.00), respectively. No specific mutational pattern was observed in thepfATPase6gene. All isolates had a K76T mutation in thepfcrtgene. In thepfdhfr-pfdhpsgenotype, quadruple mutation was frequent, and quintuple mutation was documented in 6.3% ofP. falciparumisolates. The significant failure rate of AS-SP (9.5%), although within the limit (10%) for drug policy change, was due to SP failure because of prevailing mutations inpfdhfr, I51R59N108, withpfdhps, G437and/or E540. The efficacy of this ACT needs periodic monitoring. Artemether-lumefantrine and artesunate-mefloquine are effective alternatives to the artesunate-sulfadoxine-pyrimethamine combination.

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.

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