Characterisation of the biosurfactants from phyllosphere colonising Pseudomonads and their effect on plant colonisation and diesel degradation

2020 ◽  
Author(s):  
S Oso ◽  
F Fuchs ◽  
C Übermuth ◽  
L Zander ◽  
S Daunaraviciute ◽  
...  
Keyword(s):  
Leaf Surface ◽  
Cuticular Waxes ◽  
Negative Effects ◽  
Aliphatic Compounds ◽  
Plant Colonisation ◽  
Knockout Mutants ◽  
Surfactant Production ◽  
Microbe Interactions ◽  
Diesel Degradation

AbstractBiosurfactant production is a common trait in leaf surface colonising bacteria that has been associated with increased survival and movement on leaves. At the same time the ability to degrade aliphatics is common in biosurfactant-producing leaf colonisers. Pseudomonads are common leaf colonisers and have been recognised for their ability to produce biosurfactants and degrade aliphatic compounds. In this study, we have investigated the role of biosurfactants in four non-plant plant pathogenic Pseudomonas strains by performing a series of experiments to characterise the surfactant properties, and their role during leaf colonisation and diesel degradation. The produced biosurfactants were identified using mass-spectrometry. Two strains produced viscosin-like biosurfactants and the other two produced Massetolide A-like biosurfactants which aligned with the phylogenetic relatedness between the strains. To further investigate the role of surfactant production, random Tn5 transposon mutagenesis was performed to generate knockout mutants. The knockout mutants were compared to their respective wildtypes in their ability to colonise gnotobiotic Arabidopsis thaliana and to degrade diesel. It was not possible to detect negative effects during plant colonisation in direct competition or individual colonisation experiments. When grown on diesel, knockout mutants grew significantly slower compared to their respective wildtypes. By adding isolated wildtype biosurfactants it was possible to complement the growth of the knockout mutants.ImportanceMany leaf colonising bacteria produce surfactants and are able to degrade aliphatic compounds, however, if surfactant production provides a competitive advantage during leaf colonisation is unclear. Furthermore, it is unclear if leaf colonisers take advantage of the aliphatic compounds that constitute the leaf cuticle and cuticular waxes. Here we test the effect of surfactant production on leaf colonisation and demonstrate that the lack of surfactant production decreases the ability to degrade aliphatic compounds. This indicates that leaf surface dwelling, surfactant producing bacteria contribute to degradation of environmental hydrocarbons and may be able to utilise leaf surface waxes. This has implications for plant-microbe interactions and future studies.

scholarly journals Biosurfactants produced by phyllosphere colonising pseudomonads impact on diesel degradation but not on colonisation of gnotobiotic arabidopsis leaves.

2021 ◽  
Author(s):  
S Oso ◽  
F Fuchs ◽  
C Übermuth ◽  
L Zander ◽  
S Daunaraviciute ◽  
...  
Keyword(s):  
Leaf Surface ◽  
Cuticular Waxes ◽  
Negative Effects ◽  
Aliphatic Compounds ◽  
Knockout Mutants ◽  
Surfactant Production ◽  
Microbe Interactions ◽  
Series Of Experiments ◽  
Diesel Degradation

Biosurfactant production is a common trait in leaf surface colonising bacteria that has been associated with increased survival and movement on leaves. At the same time the ability to degrade aliphatics is common in biosurfactant-producing leaf colonisers. Pseudomonads are common leaf colonisers and have been recognised for their ability to produce biosurfactants and degrade aliphatic compounds. In this study, we have investigated the role of biosurfactants in four non-plant plant pathogenic Pseudomonas strains by performing a series of experiments to characterise the surfactant properties, and their role during leaf colonisation and diesel degradation. The produced biosurfactants were identified using mass-spectrometry. Two strains produced viscosin-like biosurfactants and the other two produced Massetolide A-like biosurfactants which aligned with the phylogenetic relatedness between the strains. To further investigate the role of surfactant production, random Tn5 transposon mutagenesis was performed to generate knockout mutants. The knockout mutants were compared to their respective wild types in their ability to colonise gnotobiotic Arabidopsis thaliana and to degrade diesel or dodecane. It was not possible to detect negative effects during plant colonisation in direct competition or individual colonisation experiments. When grown on diesel, knockout mutants grew significantly slower compared to their respective wild types. When grown on dodecane, knockout mutants were less impacted compared to growth on diesel. By adding isolated wild type biosurfactants it was possible to complement the growth of the knockout mutants. Importance Many leaf colonising bacteria produce surfactants and are able to degrade aliphatic compounds, however, if surfactant production provides a competitive advantage during leaf colonisation is unclear. Furthermore, it is unclear if leaf colonisers take advantage of the aliphatic compounds that constitute the leaf cuticle and cuticular waxes. Here we test the effect of surfactant production on leaf colonisation and demonstrate that the lack of surfactant production decreases the ability to degrade aliphatic compounds. This indicates that leaf surface dwelling, surfactant producing bacteria contribute to degradation of environmental hydrocarbons and may be able to utilise leaf surface waxes. This has implications for plant-microbe interactions and future studies.

scholarly journals Different Responses in Mandarin Cultivars Uncover a Role of Cuticular Waxes in the Resistance to Citrus Canker

2020 ◽  
Vol 110 (11) ◽  
pp. 1791-1801 ◽  
Author(s):  
María A. Favaro ◽  
María C. Molina ◽  
Roxana A. Roeschlin ◽  
José Gadea ◽  
Norberto Gariglio ◽  
...  
Keyword(s):  
Leaf Surface ◽  
Chemical Properties ◽  
Citrus Canker ◽  
Primary Alcohols ◽  
Cuticular Waxes ◽  
Epidermal Surface ◽  
Faster Development ◽  
Canker Development ◽  
And Chemical Properties

‘Okitsu’ is a mandarin cultivar showing substantial resistance to X. citri subsp. citri (X. citri). We have previously shown that this cultivar has significantly lower canker incidence and severity than ‘Clemenules’, particularly during early stages of leaf development in the field. This differential response is only seen when the leaves are inoculated by spraying, suggesting that leaf surface contributes to resistance. In this work, we have studied structural and chemical properties of leaf surface barriers of both cultivars. Ultrastructural analysis showed a thicker cuticle covering epidermal surface and guard cells in young ‘Okitsu’ leaves than in ‘Clemenules’. This thicker cuticle was associated with a smaller stomatal aperture and reduced cuticle permeability. These findings correlated with an accumulation of cuticular wax components, including primary alcohols, alkanes, and fatty acids. None of these differences were observed in mature leaves, where both cultivars are equally resistant to the bacterium. Remarkably, mechanical alteration of cuticular thickness of young ‘Okitsu’ leaves allows canker development. Furthermore, cuticular waxes extracted from young ‘Okitsu’ leaves have higher antibacterial activity against X. citri than ‘Clemenules’. Taken together, these data suggest that a faster development of epicuticular waxes in ‘Okitsu’ leaves play a central role in its resistance to X. citri.

scholarly journals Sources and Assembly of Microbial Communities in Vineyards as a Functional Component of Winegrowing

2021 ◽  
Vol 12 ◽  
Author(s):  
Reid G. Griggs ◽  
Kerri L. Steenwerth ◽  
David A. Mills ◽  
Dario Cantu ◽  
Nicholas A. Bokulich
Keyword(s):  
Negative Effects ◽  
Wine Quality ◽  
Point Of Entry ◽  
General Rules ◽  
Key Factor ◽  
Microbe Interactions ◽  
Wine Flavor ◽  
Microbiome Assembly ◽  
Regional Wine

Microbiomes are integral to viticulture and winemaking – collectively termed winegrowing – where diverse fungi and bacteria can exert positive and negative effects on grape health and wine quality. Wine is a fermented natural product, and the vineyard serves as a key point of entry for quality-modulating microbiota, particularly in wine fermentations that are conducted without the addition of exogenous yeasts. Thus, the sources and persistence of wine-relevant microbiota in vineyards critically impact its quality. Site-specific variations in microbiota within and between vineyards may contribute to regional wine characteristics. This includes distinctions in microbiomes and microbiota at the strain level, which can contribute to wine flavor and aroma, supporting the role of microbes in the accepted notion of terroir as a biological phenomenon. Little is known about the factors driving microbial biodiversity within and between vineyards, or those that influence annual assembly of the fruit microbiome. Fruit is a seasonally ephemeral, yet annually recurrent product of vineyards, and as such, understanding the sources of microbiota in vineyards is critical to the assessment of whether or not microbial terroir persists with inter-annual stability, and is a key factor in regional wine character, as stable as the geographic distances between vineyards. This review examines the potential sources and vectors of microbiota within vineyards, general rules governing plant microbiome assembly, and how these factors combine to influence plant-microbe interactions relevant to winemaking.

Can trust become a factor of economic growth? Dynamic changes in the level of trust of Russian youth

2020 ◽  
pp. 92-107 ◽  
Author(s):  
A. I. Bakhtigaraeva ◽  
A. A. Stavinskaya
Keyword(s):  
Institutional Environment ◽  
Negative Effects ◽  
Dynamic Changes ◽  
Generalized Trust ◽  
Level Of Education ◽  
Advantages And Disadvantages ◽  
The Future ◽  
Analysis Of Dynamics

The article considers the role of trust in the economy, the mechanisms of its accumulation and the possibility of using it as one of the growth factors in the future. The advantages and disadvantages of measuring the level of generalized trust using two alternative questions — about trusting people in general and trusting strangers — are analyzed. The results of the analysis of dynamics of the level of generalized trust among Russian youth, obtained within the study of the Institute for National Projects in 10 regions of Russia, are presented. It is shown that there are no significant changes in trust in people in general during the study at university. At the same time, the level of trust in strangers falls, which can negatively affect the level of trust in the country as a whole, and as a result have negative effects on the development of the economy in the future. Possible causes of the observed trends and the role of universities are discussed. Also the question about the connection between the level of education and generalized trust in countries with different quality of the institutional environment is raised.

الإمام المصلح عبد الحميد بن باديس: حياته وجهوده التربوية Reformer Imam Abdal-hamid ibn Badis: His Life and Educational Reforms

2015 ◽  
Vol 12 (1) ◽  
pp. 105-152
Author(s):  
باي زكوب عبد العالي ◽  
سوهيرين محمد صوليحين
Keyword(s):  
Twentieth Century ◽  
Educational Reforms ◽  
Daily Routine ◽  
Journalism Education ◽  
Negative Effects ◽  
Educational Approach ◽  
Political Economic ◽  
Difficult Times

الملخّصيعدّ عبد الحميد بن باديس أحد العلماء الجزائريين المبرزين بالإصلاح الاجتماعي والدّيني والسّياسي والتربوي، عاش خمسين سنة في القرن العشرين الميلادي، حيث كانت ولادته سنة 1889م، وكانت وفاته سنة 1940م، ولقد فرض الواقع الجزائري إبّان فترة الاحتلال الفرنسي الذي كان يسعى إلى طمس ثوابت الأمّة الجزائرية، وخرق تاريخها، وهُويّتها، وثقافتها، ووحدتها الدينيّة، واللّغوية على ابن باديس أن يسلك نهج التربية والتعليم، قاصداً بذلك مواجهة الاحتلال الفرنسي الغاشم من خلال عدّة جبهات ومجالات كمثل مجال الصحافة، ومجال التربية والتعليم، ومجال الجمعيات، ومجال السياسة وغير ذلك، يهدف هذا البحث إلى إبراز دور عبد الحميد بن باديس في النّهوض بالأمّة الجزائريّة نحو تربيّة أفضل، وحياة أسعد، فيبدأ أوّلاً وبشكل موجز، بالتعرّف على الفترة الصعبة التي عايشها ابن باديس والمتمثلة في فترة الاحتلال الفرنسي الغاشم، وآثاره السلبية على الصعيد السياسي والاقتصادي والاجتماعي والثقافي والديني الجزائري وقتذاك، ثم يقوم ثانياً بتسليط الضّوء على حياة ابن باديس وتكوينه العلمي ورحلاته الداخلية وأسفاره الخارجية؛ ثم يسعى ثالثاً وبتعمّق، التعرّف على أعمال ابن باديس الاجتماعيّة وجهوده التربويّة التي أخذت حظّاً وافراً من حياته اليومية، والتي تركّزت على منبرين رئيسين، هما: منبر الصّحافة، ومنبر التربيّة والتعليم.الكلمات المفتاحيّة: الإمام عبد الحميد بن باديس، الاحتلال الفرنسي، التربية، الجزائر، الإصلاح.             AbstractImÉm ‘Abd al-×amÊd ibn BÉdÊs is an Algerian scientist, and eminent social, religious, political and educational reformer. He lived fifty years in the twentieth century. He was born in 1889 and died in 1940, and lived during the French occupation that attempted to distort and undermine the foundations of the Algerian nation by destroying its history, identity, culture, and religious and linguistic unity. Ibn BÉdÊs pursued an educational approach to face the brutal French occupation on several fronts, including journalism, education, civil associations, politics, etc. This paper highlights the role of ‘Abd al-×amÊd ibn BÉdÊs in the advancement of the Algerian nation toward better education and a happier life. The paper begins with a brief canvas of the difficult times in which Ibn BÉdÊs lived, and the negative effects of the brutal French occupation from political, economic, social, cultural and religious angles, besides highlighting the life of Ibn BÉdÊs, his education and his local and international travels. The focus of this research is an in-depth examination of Ibn BÉdÊs’ social and educational efforts that consumed much of his daily routine: journalism, and education.Keywords: ImÉm ‘Abd al-×amÊd ibn BÉdÊs, the French Occupation, Education, Algeria, Reform.

scholarly journals Robots as intelligent assistants to face COVID-19 pandemic

2020 ◽  
Author(s):  
Valeria Seidita ◽  
Francesco Lanza ◽  
Arianna Pipitone ◽  
Antonio Chella
Keyword(s):  
Technological Progress ◽  
World Economy ◽  
The State ◽  
Research Groups ◽  
Negative Effects ◽  
The World ◽  
Intelligent Assistants

Abstract Motivation The epidemic at the beginning of this year, due to a new virus in the coronavirus family, is causing many deaths and is bringing the world economy to its knees. Moreover, situations of this kind are historically cyclical. The symptoms and treatment of infected patients are, for better or worse even for new viruses, always the same: more or less severe flu symptoms, isolation and full hygiene. By now man has learned how to manage epidemic situations, but deaths and negative effects continue to occur. What about technology? What effect has the actual technological progress we have achieved? In this review, we wonder about the role of robotics in the fight against COVID. It presents the analysis of scientific articles, industrial initiatives and project calls for applications from March to now highlighting how much robotics was ready to face this situation, what is expected from robots and what remains to do. Results The analysis was made by focusing on what research groups offer as a means of support for therapies and prevention actions. We then reported some remarks on what we think is the state of maturity of robotics in dealing with situations like COVID-19.

Open-mindedness as a Corrective Virtue

Philosophy ◽  
2020 ◽  
Vol 96 (1) ◽  
pp. 73-97
Author(s):  
Hassan Alsharif ◽  
John Symons
Keyword(s):  
Recent Literature ◽  
Confirmation Bias ◽  
Negative Effects ◽  
Shed Light

AbstractThis paper argues that open-mindedness is a corrective virtue. It serves as a corrective to the epistemic vice of confirmation bias. Specifically, open-mindedness is the epistemically virtuous disposition to resist the negative effects of confirmation bias on our ability to reason well and to evaluate evidence and arguments. As part of the defense and presentation of our account, we explore four discussions of open-mindedness in the recent literature. All four approaches have strengths and shed light on aspects of the virtue of open-mindedness. Each mentions various symptoms of confirmation bias and some explore aspects of the corrective role of open-mindedness. However, ours is the first to explicitly identify open-mindedness as a corrective virtue to the specific epistemic vice of confirmation bias. We show how the corrective account also permits a response to the concern that open-mindedness might not actually count as a virtue.

Overcoming counter-knowledge through telemedicine communication technologies

2017 ◽  
Vol 31 (7/8) ◽  
pp. 730-745 ◽  
Author(s):  
Jorge Cegarra-Sanchez ◽  
Juan-Gabriel Cegarra-Navarro ◽  
Anthony Wensley ◽  
Jose Diaz Manzano
Keyword(s):  
Learning Process ◽  
Design Methodology ◽  
Communication Technologies ◽  
Regional Hospital ◽  
Potential Contribution ◽  
Exploration And Exploitation ◽  
Negative Effects ◽  
Content Type

Purpose Knowledge acquired from sources of unverified information such as gossip, partial truths or lies, in this paper it is termed as “counter-knowledge.” The purpose of this paper is to explore this topic through an exploration of the links between a Hospital-in-the-Home Units (HHUs) learning process (LP), counter-knowledge, and the utilization of communication technologies. The following two questions are addressed: Does the reduction of counter-knowledge result in the utilization of communication technologies? Does the development of counter-knowledge hinder the LP? Design/methodology/approach This paper examines the relevance of communication technologies to the exploration and exploitation of knowledge for 252 patients of a (HHU) within a Spanish regional hospital. The data collected was analyzed using the PLS-Graph. Findings To HHU managers, this study offers a set of guidelines to assist in their gaining an understanding of the role of counter-knowledge in organizational LPs and the potential contribution of communication technologies. Our findings support the proposition that the negative effects of counter-knowledge can be mitigated by using communication technologies. Originality/value It is argued in this paper that counter-knowledge may play a variety of different roles in the implementation of LPs. Specifically, the assignment of communication technologies to homecare units has given them the means to filter counter-knowledge and prevent users from any possible problems caused by such counter-knowledge.

scholarly journals Effects of Employee Sickness Presence on Customer Repurchase and Recommendation Intentions: The Role of Customer Affective Reactions

2021 ◽  
Author(s):  
Carolin Dietz ◽  
Hannes Zacher
Keyword(s):  
Service Sector ◽  
Productivity Loss ◽  
Phone Call ◽  
Negative Effects ◽  
Disease Avoidance ◽  
Positive Effects ◽  
Sickness Presence ◽  
Organizational Consequences ◽  
Health Deterioration

AbstractSickness presence can have important individual and organizational consequences, such as health deterioration or productivity loss. Additional risks, such as negative customer reactions, may be particularly relevant in the service sector. Based on affective events theory and appraisal theories, we hypothesize that employee sickness presence negatively impacts customer repurchase and recommendation intentions. Furthermore, we explore potential affective mechanisms of these effects, including disease avoidance, personal anger, moral outrage, post-consumption guilt, and customer compassion for the employee. We conducted four studies, including three experimental vignette methodology studies (Ns = 227, 72, and 763) and a qualitative study (N = 54). In Study 1, employee sickness presence had negative effects on repurchase and recommendation intentions. Results of Study 2 show that customers experienced disgust, fear, anger, guilt, compassion, and indifference in response to sickness presence. In Study 3, anger explained the negative effects of employee sickness presence on repurchase and recommendation intentions, while appraisals of moral fairness were negatively related to both customer intentions. Finally, in Study 4, disgust and anger explained negative effects, while fear, guilt, and compassion explained positive effects of employee sickness presence on customer intentions. Appraisals of goal incongruence, reduced agency of the customer, and uncertainty were negatively related to customer intentions. The physical absence of the customer in the service encounter (phone call) mitigated the experience of disgust, fear, and anger, whereas it exacerbated feelings of compassion for the ill employee.

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