scholarly journals A microfluidic device for inferring metabolic landscapes in yeast monolayer colonies

2019 ◽  
Author(s):  
Zoran S Marinkovic ◽  
Clément Vulin ◽  
Mislav Acman ◽  
Xiaohu Song ◽  
Jean Marc Di Meglio ◽  
...  
Keyword(s):  
Genetic Networks ◽  
Physiological Adaptation ◽  
Spatial Correlations ◽  
Amino Acid Availability ◽  
Hexose Transporters ◽  
Metabolic Interactions ◽  
Global Understanding ◽  
Cellular Development ◽  
Glucose Availability ◽  
External Glucose

AbstractMicrobial colonies are fascinating structures in which growth and internal organization reflect complex morphogenetic processes. Here, we generated a microfluidics device with arrays of long monolayer yeast colonies to further global understanding of how intercellular metabolic interactions affect the internal structure of colonies within defined boundary conditions. We observed the emergence of stable glucose gradients using fluorescently labelled hexose transporters and quantified the spatial correlations with intracolony growth rates and expression of other genes regulated by glucose availability. These landscapes depended on the external glucose concentration as well as secondary gradients, e.g., amino acid availability. This work demonstrates the regulatory genetic networks governing cellular physiological adaptation are the key to internal structuration of cellular assemblies. This approach could be used in the future to decipher the interplay between long-range metabolic interactions, cellular development and morphogenesis in more complex systems.

scholarly journals A microfluidic device for inferring metabolic landscapes in yeast monolayer colonies

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Zoran S Marinkovic ◽  
Clément Vulin ◽  
Mislav Acman ◽  
Xiaohu Song ◽  
Jean-Marc Di Meglio ◽  
...  
Keyword(s):  
Colony Growth ◽  
Genetic Networks ◽  
Physiological Adaptation ◽  
Spatial Correlations ◽  
Amino Acid Availability ◽  
Hexose Transporters ◽  
Metabolic Interactions ◽  
Global Understanding ◽  
Cellular Development ◽  
External Glucose

Microbial colonies are fascinating structures in which growth and internal organization reflect complex morphogenetic processes. Here, we generated a microfluidics device with arrays of long monolayer yeast colonies to further global understanding of how intercellular metabolic interactions affect the internal structure of colonies within defined boundary conditions. We observed the emergence of stable glucose gradients using fluorescently labeled hexose transporters and quantified the spatial correlations with intra-colony growth rates and expression of other genes regulated by glucose availability. These landscapes depended on the external glucose concentration as well as secondary gradients, for example amino acid availability. This work demonstrates the regulatory genetic networks governing cellular physiological adaptation are the key to internal structuration of cellular assemblies. This approach could be used in the future to decipher the interplay between long-range metabolic interactions, cellular development and morphogenesis in more complex systems.

scholarly journals Bacterial glycogen provides short-term benefits in changing environments

2019 ◽  
Author(s):  
Karthik Sekar ◽  
Stephanie M. Linker ◽  
Jen Nguyen ◽  
Alix Grünhagen ◽  
Roman Stocker ◽  
...  
Keyword(s):  
Carbon Sources ◽  
Physiological Adaptation ◽  
Short Term ◽  
Changing Environments ◽  
Nutritional Conditions ◽  
Mutant Strains ◽  
Glycogen Utilization ◽  
Lag Times ◽  
Glucose Availability

AbstractChanging nutritional conditions challenge microbes and shape their evolutionary optimization. Here we investigated the role of glycogen in dynamic physiological adaptation of Escherichia coli to fluctuating nutrients following carbon starvation using real-time metabolomics. We found significant metabolic activity remaining after the depletion of environmental glucose that was linked to a rapid utilization of intracellular glycogen. Glycogen was depleted by 80% within minutes of glucose starvation and similarly replenished within minutes of glucose availability. These fast timescales of glycogen utilization correspond to the short-term benefits that glycogen provided to cells undergoing various physiological transitions. Cells capable of utilizing glycogen exhibited shorter lag times than glycogen mutants when starved between different carbon sources. The ability to utilize glycogen was also important for the transition between planktonic and biofilm lifestyles and enabled increased glucose uptake during pulses of limited glucose availability. While wild-type and mutant strains exhibited comparable growth rates in steady environments, mutants deficient in glycogen utilization grew more poorly in environments that fluctuated on minute-scales between carbon availability and starvation. Altogether, these results highlight an underappreciated role of glycogen to rapidly provide carbon and energy in changing environments, thereby increasing survival and competition capabilities in fluctuating and nutrient poor conditions.

scholarly journals Separate responses of karyopherins to glucose and amino acid availability regulate nucleocytoplasmic transport

2014 ◽  
Vol 25 (18) ◽  
pp. 2840-2852 ◽  
Author(s):  
Hsiao-Yun Huang ◽  
Anita K. Hopper
Keyword(s):  
Amino Acid ◽  
Nutrient Availability ◽  
Nuclear Export ◽  
Family Members ◽  
Glucose Deprivation ◽  
Nucleocytoplasmic Transport ◽  
Subcellular Trafficking ◽  
Family Function ◽  
Amino Acid Availability ◽  
Glucose Availability

The importin-β family members (karyopherins) mediate the majority of nucleocytoplasmic transport. Msn5 and Los1, members of the importin-β family, function in tRNA nuclear export. tRNAs move bidirectionally between the nucleus and the cytoplasm. Nuclear tRNA accumulation occurs upon amino acid (aa) or glucose deprivation. To understand the mechanisms regulating tRNA subcellular trafficking, we investigated whether Msn5 and Los1 are regulated in response to nutrient availability. We provide evidence that tRNA subcellular trafficking is regulated by distinct aa-sensitive and glucose-sensitive mechanisms. Subcellular distributions of Msn5 and Los1 are altered upon glucose deprivation but not aa deprivation. Redistribution of tRNA exportins from the nucleus to the cytoplasm likely provides one mechanism for tRNA nuclear distribution upon glucose deprivation. We extended our studies to other members of the importin-β family and found that all tested karyopherins invert their subcellular distributions upon glucose deprivation but not aa deprivation. Glucose availability regulates the subcellular distributions of karyopherins likely due to alteration of the RanGTP gradient since glucose deprivation causes redistribution of Ran. Thus nuclear–cytoplasmic distribution of macromolecules is likely generally altered upon glucose deprivation due to collapse of the RanGTP gradient and redistribution of karyopherins between the nucleus and the cytoplasm.

Advancing a Global Understanding of Adolescence

PsycCRITIQUES ◽  
2012 ◽  
Vol 57 (37) ◽  
Author(s):  
Laura Ferrer-Wreder ◽  
Sarah Thomas
Keyword(s):  
Global Understanding

The Colonial Documentary Film in South and South-East Asia

2017 ◽  
Keyword(s):  
East Asia ◽  
Subject Matter ◽  
Documentary Film ◽  
East Asian ◽  
South East Asia ◽  
Post Colonial ◽  
Historical Perspectives ◽  
The Third ◽  
Wide Range ◽  
Global Understanding

Writing from a wide range of historical perspectives, contributors to the anthology shed new light on historical, theoretical and empirical issues pertaining to the documentary film, in order to better comprehend the significant transformations of the form in colonial, late colonial and immediate post-colonial and postcolonial times in South and South-East Asia. In doing so, this anthology addresses an important gap in the global understanding of documentary discourses, practices, uses and styles. Based upon in-depth essays written by international authorities in the field and cutting-edge doctoral projects, this anthology is the first to encompass different periods, national contexts, subject matter and style in order to address important and also relatively little-known issues in colonial documentary film in the South and South-East Asian regions. This anthology is divided into three main thematic sections, each of which crosses national or geographical boundaries. The first section addresses issues of colonialism, late colonialism and independence. The second section looks at the use of the documentary film by missionaries and Christian evangelists, whilst the third explores the relation between documentary film, nationalism and representation.

Quadratic Discriminant Analysis of Spatially Correlated Data

2001 ◽  
Vol 6 (2) ◽  
pp. 15-28 ◽  
Author(s):  
K. Dučinskas ◽  
J. Šaltytė
Keyword(s):  
Discriminant Function ◽  
Error Rate ◽  
Gaussian Random Field ◽  
Correlated Data ◽  
Covariance Matrices ◽  
Classification Rule ◽  
Spatial Correlations ◽  
Linear Quadratic ◽  
Spatial Correlation Function ◽  
Spatially Correlated

The problem of classification of the realisation of the stationary univariate Gaussian random field into one of two populations with different means and different factorised covariance matrices is considered. In such a case optimal classification rule in the sense of minimum probability of misclassification is associated with non-linear (quadratic) discriminant function. Unknown means and the covariance matrices of the feature vector components are estimated from spatially correlated training samples using the maximum likelihood approach and assuming spatial correlations to be known. Explicit formula of Bayes error rate and the first-order asymptotic expansion of the expected error rate associated with quadratic plug-in discriminant function are presented. A set of numerical calculations for the spherical spatial correlation function is performed and two different spatial sampling designs are compared.

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