scholarly journals A systems approach to model the relationship between aflatoxin gene cluster expression, environmental factors, growth and toxin production by Aspergillus flavus

2011 ◽  
Vol 9 (69) ◽  
pp. 757-767 ◽  
Author(s):  
Ahmed Abdel-Hadi ◽  
Markus Schmidt-Heydt ◽  
Roberto Parra ◽  
Rolf Geisen ◽  
Naresh Magan
Keyword(s):  
Gene Expression ◽  
Environmental Factors ◽  
Aspergillus Flavus ◽  
Biosynthetic Pathway ◽  
Systems Approach ◽  
Toxin Production ◽  
Relative Expression ◽  
Temperature Conditions ◽  
The Impact ◽  
The Relationship

A microarray analysis was used to examine the effect of combinations of water activity ( a w , 0.995–0.90) and temperature (20–42°C) on the activation of aflatoxin biosynthetic genes (30 genes) in Aspergillus flavus grown on a conducive YES (20 g yeast extract, 150 g sucrose, 1 g MgSO 4 ·7H 2 O) medium. The relative expression of 10 key genes ( aflF , aflD , aflE , aflM , aflO , aflP , aflQ , aflX , aflR and aflS ) in the biosynthetic pathway was examined in relation to different environmental factors and phenotypic aflatoxin B 1 (AFB 1 ) production. These data, plus data on relative growth rates and AFB 1 production under different a w × temperature conditions were used to develop a mixed-growth-associated product formation model. The gene expression data were normalized and then used as a linear combination of the data for all 10 genes and combined with the physical model. This was used to relate gene expression to a w and temperature conditions to predict AFB 1 production. The relationship between the observed AFB 1 production provided a good linear regression fit to the predicted production based in the model. The model was then validated by examining datasets outside the model fitting conditions used (37°C, 40°C and different a w levels). The relationship between structural genes ( aflD , aflM ) in the biosynthetic pathway and the regulatory genes ( aflS , aflJ ) was examined in relation to a w and temperature by developing ternary diagrams of relative expression. These findings are important in developing a more integrated systems approach by combining gene expression, ecophysiological influences and growth data to predict mycotoxin production. This could help in developing a more targeted approach to develop prevention strategies to control such carcinogenic natural metabolites that are prevalent in many staple food products. The model could also be used to predict the impact of climate change on toxin production.

scholarly journals Integrating toxin gene expression, growth and fumonisin B 1 and B 2 production by a strain of Fusarium verticillioides under different environmental factors

2013 ◽  
Vol 10 (85) ◽  
pp. 20130320 ◽  
Author(s):  
Angel Medina ◽  
Markus Schmidt-Heydt ◽  
Diana L. Cárdenas-Chávez ◽  
Roberto Parra ◽  
Rolf Geisen ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Systems Approach ◽  
Fusarium Verticillioides ◽  
Model Fitting ◽  
Toxin Production ◽  
Product Formation ◽  
Toxin Gene ◽  
Relative Expression ◽  
Food Commodities

The objective of this study was to integrate data on the effect of water activity ( a w ; 0.995–0.93) and temperature (20–35°C) on activation of the biosynthetic FUM genes, growth and the mycotoxins fumonisin (FB 1 , FB 2 ) by Fusarium verticillioides in vitro . The relative expression of nine biosynthetic cluster genes ( FUM1 , FUM7 , FUM10 , FUM11 , FUM12 , FUM13 , FUM14 , FUM16 and FUM19 ) in relation to the environmental factors was determined using a microarray analysis. The expression was related to growth and phenotypic FB 1 and FB 2 production. These data were used to develop a mixed-growth-associated product formation model and link this to a linear combination of the expression data for the nine genes. The model was then validated by examining datasets outside the model fitting conditions used (35°C). The relationship between the key gene ( FUM1 ) and other genes in the cluster ( FUM11, FUM13, FUM9, FUM14 ) were examined in relation to a w , temperature, FB 1 and FB 2 production by developing ternary diagrams of relative expression. This model is important in developing an integrated systems approach to develop prevention strategies to control fumonisin biosynthesis in staple food commodities and could also be used to predict the potential impact that climate change factors may have on toxin production.

scholarly journals Research on the Relationship between Shared Leadership and Individual Creativity-Qualitative Comparative Analysis on the Basis of Clear Set

2021 ◽  
Vol 13 (10) ◽  
pp. 5445
Author(s):  
Muyun Sun ◽  
Jigan Wang ◽  
Ting Wen
Keyword(s):  
Comparative Analysis ◽  
Environmental Factors ◽  
Shared Leadership ◽  
Management Practices ◽  
Qualitative Comparative Analysis ◽  
Necessary Condition ◽  
The Individual ◽  
The Impact ◽  
The Relationship ◽  
Sufficient And Necessary Condition

Creativity is the key to obtaining and maintaining competitiveness of modern organizations, and it has attracted much attention from academic circles and management practices. Shared leadership is believed to effectively influence team output. However, research on the impact of individual creativity is still in its infancy. This study adopts the qualitative comparative analysis method, taking 1584 individuals as the research objects, underpinned by a questionnaire-based survey. It investigates the influence of the team’s shared leadership network elements and organizational environmental factors on the individual creativity. We have found that there are six combination of conditions of shared leadership and organizational environmental factors constituting sufficient combination of conditions to increase or decrease individual creativity. Moreover, we have noticed that the low network density of shared leadership is a sufficient and necessary condition of reducing individual creativity. Our results also provide management suggestions for practical activities during the team management.

scholarly journals Mutational Signatures as Sensors of Environmental Exposures: Role of Smoking in COVID-19 Vulnerabilities

2021 ◽  
Author(s):  
Yoo-Ah Kim ◽  
Ermin Hodzic ◽  
Ariella Saslafsky ◽  
Damian Wojtowicz ◽  
Bayarbaatar Amgalan ◽  
...  
Keyword(s):  
Gene Expression ◽  
Environmental Factors ◽  
Disease Progression ◽  
Environmental Exposures ◽  
Biological Processes ◽  
Mutational Signatures ◽  
Mutational Signature ◽  
The Impact ◽  
Pathway Level

Background: Environmental exposures such as smoking are widely recognized risk factors in the emergence of lung diseases such as lung cancer and acute respiratory distress syndrome (ARDS). However, the strength of environmental exposures is difficult to measure, making it challenging to understand their impacts. On the other hand, some COVID-19 patients develop ARDS in an unfavorable disease progression and smoking has been suggested as a potential risk factor among others. Yet initial studies on COVID-19 cases reported contradictory results on the effects of smoking on the disease. Some suggest that smoking might have a protective effect against it while other studies report an increased risk. A better understanding of how the exposure to smoking and other environmental factors affect biological processes relevant to SARS-CoV-2 infection and unfavorable disease progression is needed. Approach: In this study, we utilize mutational signatures associated with environmental factors as sensors of their exposure level. Many environmental factors including smoking are mutagenic and leave characteristic patterns of mutations, called mutational signatures, in affected genomes. We postulated that analyzing mutational signatures, combined with gene expression, can shed light on the impact of the mutagenic environmental factors to the biological processes. In particular, we utilized mutational signatures from lung adenocarcinoma (LUAD) data set collected in TCGA to investigate the role of environmental factors in COVID-19 vulnerabilities. Integrating mutational signatures with gene expression in normal tissues and using a pathway level analysis, we examined how the exposure to smoking and other mutagenic environmental factors affects the infectivity of the virus and disease progression. Results: By delineating changes associated with smoking in pathway-level gene expression and cell type proportions, our study demonstrates that mutational signatures can be utilized to study the impact of exogenous mutagenic factors on them. Consistent with previous findings, our analysis showed that smoking mutational signature (SBS4) is associated with activation of cytokines mediated singling pathways, leading to inflammatory responses. Smoking related changes in cell composition were also observed, including the correlation of SBS4 with the expansion of goblet cells. On the other hand, increased basal cells and decreased ciliated cells in proportion were associated with the strength of a different mutational signature (SBS5), which is present abundantly but not exclusively in smokers. In addition, we found that smoking increases the expression levels of genes that are upregulated in severe COVID-19 cases. Jointly, these results suggest an unfavorable impact of smoking on the disease progression and also provide novel findings on how smoking impacts biological processes in lung.

scholarly journals Environmental factors and cardiovascular diseases

2021 ◽  
Vol 100 (3) ◽  
pp. 223-228
Author(s):  
Aleksey M. Chaulin ◽  
Dmitry V. Duplyakov
Keyword(s):  
Air Pollution ◽  
Cardiovascular Diseases ◽  
Environmental Factors ◽  
Future Research ◽  
Prevention Measures ◽  
Solar Insolation ◽  
Treatment And Prevention ◽  
Pubmed Database ◽  
The Impact ◽  
The Relationship

Introduction. New advances in the diagnosis and treatment of cardiovascular diseases (CVD), as practice shows, are not able to significantly improve the statistical indicators of morbidity and mortality of CVD. This fact indicates that there are additional factors and mechanisms that are important to consider, both for prevention and for the most optimal management of patients. Recently, the relationship between environmental and lifestyle factors with CVD has been actively studied. However, despite understanding the relationship between environmental factors and various diseases, including CVD, the mechanisms by which specific factors increase or decrease the risk of developing CVD are not yet fully understood, and a number of studies are contradictory. The aim of our work was to generalize existing data on the impact of such critical environmental factors as air pollution and solar insolation on the cardiovascular system, as well as to comprehensively discuss the mechanisms by which these environmental factors can participate in the development and progression of CVD. To achieve our work’s goal, we analyzed modern foreign literature using the PubMed database. Conclusion. According to numerous experimental and clinical studies, air pollution and solar insolation deficiency play an essential role in developing CVD and the aggravation of patients with various CVD (atherosclerosis, hypertension, coronary heart disease, heart failure, myocardial infarction, and stroke). Thus, air pollution and lack of solar insolation can be considered as critical risk factors for CVD. Future research should focus on the study and establishment of specific pathogenetic mechanisms by which environmental factors affect the cardiovascular system’s health to develop effective treatment and prevention measures.

The Impact of Environmental Factors on Malaria Prevalence in a Peri-Urban Community in Kwara State, Nigeria

2014 ◽  
Vol 3 (3) ◽  
pp. 173
Author(s):  
Olubunmi Ajike Mokuolu ◽  
Oluwayemisi D Adegboye ◽  
Olugbenga A Mokuolu
Keyword(s):  
Environmental Factors ◽  
Malaria Prevalence ◽  
Sampling Procedure ◽  
Multiple Regression Equation ◽  
Published Data ◽  
Community Based ◽  
The Impact ◽  
The Relationship ◽  
Selection Of ◽  
Structured Questionnaire

<p>There is a consensus on the relationship between Malaria Prevalence (MP) and Environmental Factors (EF); however, there is a dearth of published data providing this evidence in a quantifiable way. This community based study was undertaken to identify the magnitude of the relationship between MP and key environmental factors in Okelele, Ilorin East Local Government Area of Kwara State, Nigeria. A multi-staged sampling procedure was adopted for the selection of 501 children from 200 households. Children under the age of 14 years in the selected households were sampled to obtain baseline MP using malaria Rapid Diagnostic Test (mRDT) kit. Key household informant interviews and structured questionnaire were used. Relevant socio-demographic characteristics of the households, EF and non EF were determined. Acquired data was analyzed using statistical tools to determine the relationship between various independent variables and mRDT. Variables were also entered into a multiple regression equation for the generation of a mathematical model. Ethical consent was obtained from the parents before samples were taken.The study showed that EF contributed to MP in the study area.  Integrated waste management system, and regular environmental sanitation were recommended.</p>

scholarly journals Integrating gene expression, ecology and mycotoxin production by Fusarium and Aspergillus species in relation to interacting environmental factors

2016 ◽  
Vol 9 (5) ◽  
pp. 673-684 ◽  
Author(s):  
N. Magan ◽  
A. Medina
Keyword(s):  
Environmental Factors ◽  
Fusarium Verticillioides ◽  
Fusarium Culmorum ◽  
Toxin Production ◽  
Stress Conditions ◽  
Toxin Gene ◽  
Biosynthetic Genes ◽  
Mycotoxin Production ◽  
Extreme Stress ◽  
Temperature Conditions

Environmental factors, such as water availability (water activity, aw), temperature and their interactions, have a significant impact on the life cycle of mycotoxigenic fungi. Growth and mycotoxin production are influenced by these interacting factors resulting in a broader range of aw × temperature conditions for germination, than growth or mycotoxin production. The biosynthetic genes are mostly clustered together and by using microarrays with sub-arrays for specific mycotoxins, such as trichothecenes, fumonisins and aflatoxins it has been possible to examine the relationship between interacting aw × temperature conditions on growth, toxin gene cluster expression and relate these to phenotypic toxin production. The data for groups of biosynthetic genes (Fusarium culmorum/Fusarium graminearum; Fusarium verticillioides; Aspergillus flavus) were integrated with data on growth and mycotoxin production under different aw × temperature conditions using a mixed growth model. This was used to correlate these factors and predict toxin levels which may be produced under different abiotic stress conditions. Indeed, the relative importance of the different genes could be examined using ternary diagrams of the relative expression of 3 genes at a time in relation to aw, temperature and mycotoxin production to identify the most important relationships. The effect of three-way interacting environmental factors representative of climate change (CC) scenarios (water stress × temperature (+2-4 °C) × elevated CO2 (350-400 vs 650 and 1000 ppm) on growth and mycotoxin production by A. flavus and by species of the Aspergillus section Circumdati and section Nigri have been determined. These studies on maize grain and coffee, respectively, suggest that while growth may not be significantly affected, mycotoxin production may be stimulated by CC factors. This approach to integrate such data sets and model the relationships could be a powerful tool for predicting the relative toxin production under extreme stress conditions, including CC scenarios.

scholarly journals Could Environment Affect the Mutation of H1N1 Influenza Virus?

2020 ◽  
Vol 17 (9) ◽  
pp. 3092
Author(s):  
Dong Jiang ◽  
Qian Wang ◽  
Zhihua Bai ◽  
Heyuan Qi ◽  
Juncai Ma ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Environmental Factors ◽  
Social Development ◽  
Influenza A ◽  
H1n1 Influenza ◽  
Influenza A Viruses ◽  
Nighttime Light ◽  
Complex Relationships ◽  
The Impact ◽  
The Relationship

H1N1 subtype influenza A viruses are the most common type of influenza A virus to infect humans. The two major outbreaks of the virus in 1918 and 2009 had a great impact both on human health and social development. Though data on their complete genome sequences have recently been obtained, the evolution and mutation of A/H1N1 viruses remain unknown to this day. Among many drivers, the impact of environmental factors on mutation is a novel hypothesis worth studying. Here, a geographically disaggregated method was used to explore the relationship between environmental factors and mutation of A/H1N1 viruses from 2000–2019. All of the 11,721 geo-located cases were examined and the data was analysed of six environmental elements according to the time and location (latitude and longitude) of those cases. The main mutation value was obtained by comparing the sequence of the influenza virus strain with the earliest reported sequence. It was found that environmental factors systematically affect the mutation of A/H1N1 viruses. Minimum temperature displayed a nonlinear, rising association with mutation, with a maximum ~15 °C. The effects of precipitation and social development index (nighttime light) were more complex, while population density was linearly and positively correlated with mutation of A/H1N1 viruses. Our results provide novel insight into understanding the complex relationships between mutation of A/H1N1 viruses and environmental factors.

Assessment of Environmental Factors on Listeria monocytogenes Scott A inlA Gene Expression by Relative Quantitative Taqman Real-Time Reverse Transcriptase PCR

2006 ◽  
Vol 69 (11) ◽  
pp. 2754-2757 ◽  
Author(s):  
SCOTT E. HANNA ◽  
HUA H. WANG
Keyword(s):  
Gene Expression ◽  
Listeria Monocytogenes ◽  
Environmental Factors ◽  
Reverse Transcriptase ◽  
Real Time ◽  
Virulence Factors ◽  
Virulence Factor ◽  
Internal Standard ◽  
Reverse Transcriptase Pcr ◽  
The Impact

Several virulence factors are involved in Listeria monocytogenes pathogenicity. L. monocytogenes internalins, particularly internalin A, are required for bacterial adhesion to and invasion of human intestinal epithelial cells. The expression of inter-nalins is thus related to virulence. Identification of conditions involved in regulating the expression of L. monocytogenes virulence factors is essential for developing targeted strategies to control listeriosis incidence and improving therapeutic approaches. The primary aim of this study was to develop a quantitative real-time reverse transcriptase PCR platform to study the impact of environmental factors on L. monocytogenes Scott A virulence factor expression, particularly in potentially complex ecosystems. A Taqman PCR–based, rapid quantitative gene expression evaluation method was established with the L. monocytogenes ribosomal protein L4 encoding gene used as an internal standard. Our data suggest that inlA expression is influenced by food composition and temperature, indicating that certain food processing or storage conditions, such as the use of lactic and acetic acids at common storage temperatures, could affect the expression of L. monocytogenes virulence factor.

Climate change factors and Aspergillus flavus: effects on gene expression, growth and aflatoxin production

2015 ◽  
Vol 8 (2) ◽  
pp. 171-179 ◽  
Author(s):  
Á Medina ◽  
A. Rodríguez ◽  
Y. Sultan ◽  
N. Magan
Keyword(s):  
Climate Change ◽  
Gene Expression ◽  
Water Stress ◽  
Aspergillus Flavus ◽  
Climatic Factors ◽  
Aflatoxin Production ◽  
Scientific Data ◽  
Effect Of Temperature ◽  
Mycotoxigenic Fungi ◽  
The Impact

The objectives of this study were to obtain scientific data on the impact that interactions between water stress (water activity (aw); 0.97, 0.95, 0.92), temperature (34, 37 °C) and CO2 exposure (350, 650, 1000 ppm) may have on the growth, gene expression of biosynthetic genes (aflD, aflR), and phenotypic aflatoxin B1 (AFB1) production by a type strain of Aspergillus flavus on a conducive medium. The study showed that while aw affected growth there was no statistically significant effect of temperature or CO2 exposure. The effect of these interacting factors on aflD and aflR gene expression showed that at 34 °C there was maximum relative expression of aflD under the control conditions (34 °C, 350 ppm) with a decrease in expression with elevated CO2 and water stress. For aflR expression at 34 °C, there was a significant increase in expression, but only at 0.92 aw and 650 ppm CO2. However, at 37 °C, there was a significant increase in expression of both aflD and aflR at 0.95 and 0.92 aw and 650 and 1000 ppm CO2. There was an associated increase in AFB1 in these treatments. In contrast, at 34 °C there were no significant differences for interacting treatments. This is the first study to examine these three-way interacting climatic factors on growth and mycotoxin production by a strain of A. flavus. This provides data that are necessary to help predict the real impacts of climate change on mycotoxigenic fungi.

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