Morphogenesis of Phototrophic Biofilms is Controlled by Hydraulic Constraints and Enabled by Architectural Plasticity

2020 ◽  
Author(s):  
Anna Depetris ◽  
Hannes Peter ◽  
Ankur Deep Bordoloi ◽  
Hippolyte Bernard ◽  
Amin Niayifar ◽  
...  
Keyword(s):  
Phototrophic Biofilms ◽  
Architectural Plasticity

Photosynthetic performance of phototrophic biofilms in extreme acidic environments

2011 ◽  
Vol 13 (8) ◽  
pp. 2351-2358 ◽  
Author(s):  
Virginia Souza-Egipsy ◽  
María Altamirano ◽  
Ricardo Amils ◽  
Angeles Aguilera
Keyword(s):  
Photosynthetic Performance ◽  
Phototrophic Biofilms ◽  
Acidic Environments

scholarly journals Axenic Biofilm Formation and Aggregation bySynechocystissp. Strain PCC 6803 Are Induced by Changes in Nutrient Concentration and Require Cell Surface Structures

2019 ◽  
Vol 85 (7) ◽  
Author(s):  
Rey Allen ◽  
Bruce E. Rittmann ◽  
Roy Curtiss
Keyword(s):  
Biofilm Formation ◽  
Molecular Mechanisms ◽  
Type Iv Pili ◽  
Biofuel Production ◽  
Oxygenic Photosynthesis ◽  
Phototrophic Biofilm ◽  
Bg11 Medium ◽  
Phototrophic Biofilms ◽  
Type Iv ◽  
Cell Surface Structures

ABSTRACTPhototrophic biofilms are key to nutrient cycling in natural environments and bioremediation technologies, but few studies describe biofilm formation by pure (axenic) cultures of a phototrophic microbe. The cyanobacteriumSynechocystissp. strain PCC 6803 (hereSynechocystis) is a model microorganism for the study of oxygenic photosynthesis and biofuel production. We report here that wild-type (WT)Synechocystiscaused extensive biofilm formation in a 2,000-liter outdoor nonaxenic photobioreactor under conditions attributed to nutrient limitation. We developed a biofilm assay and found that axenicSynechocystisforms biofilms of cells and extracellular material but only when cells are induced by an environmental signal, such as a reduction in the concentration of growth medium BG11. Mutants lacking cell surface structures, namely type IV pili and the S-layer, do not form biofilms. To further characterize the molecular mechanisms of cell-cell binding bySynechocystis, we also developed a rapid (8-h) axenic aggregation assay. Mutants lacking type IV pili were unable to aggregate, but mutants lacking a homolog to Wza, a protein required for type 1 exopolysaccharide export inEscherichia coli, had a superbinding phenotype. In WT cultures, 1.2× BG11 medium induced aggregation to the same degree as 0.8× BG11 medium. Overall, our data support that Wza-dependent exopolysaccharide is essential to maintain stable, uniform suspensions of WTSynechocystiscells in unmodified growth medium and that this mechanism is counteracted in a pilus-dependent manner under altered BG11 concentrations.IMPORTANCEMicrobes can exist as suspensions of individual cells in liquids and also commonly form multicellular communities attached to surfaces. Surface-attached communities, called biofilms, can confer antibiotic resistance to pathogenic bacteria during infections and establish food webs for global nutrient cycling in the environment. Phototrophic biofilm formation is one of the earliest phenotypes visible in the fossil record, dating back over 3 billion years. Despite the importance and ubiquity of phototrophic biofilms, most of what we know about the molecular mechanisms, genetic regulation, and environmental signals of biofilm formation comes from studies of heterotrophic bacteria. We aim to help bridge this knowledge gap by developing new assays forSynechocystis, a phototrophic cyanobacterium used to study oxygenic photosynthesis and biofuel production. With the aid of these new assays, we contribute to the development ofSynechocystisas a model organism for the study of axenic phototrophic biofilm formation.

scholarly journals Biological Control of Phototrophic Biofilms in a Show Cave: The Case of Nerja Cave

2020 ◽  
Vol 10 (10) ◽  
pp. 3448
Author(s):  
Valme Jurado ◽  
Yolanda del Rosal ◽  
Jose Gonzalez-Pimentel ◽  
Bernardo Hermosin ◽  
Cesareo Saiz-Jimenez
Keyword(s):  
Biological Control ◽  
Direct Evidence ◽  
Mineral Surfaces ◽  
Future Studies ◽  
Artificial Lighting ◽  
Phototrophic Biofilms ◽  
Phototrophic Microorganisms ◽  
Physical Chemical ◽  
Show Caves ◽  
Physical And Chemical

Cyanobacteria and microalgae are usually found in speleothems, rocks and walls of show caves exposed to artificial lighting. These microorganisms develop as biofilms coating the mineral surfaces and producing aesthetic, physical and chemical deterioration. A wide number of physical, chemical and environmental-friendly methods have been used for controlling the biofilms with different results. Natural biological control has been suggested by some authors as a theoretical approach but without direct evidence or application. Here we report the finding of a natural biological control of phototrophic biofilms on the speleothems of Nerja Cave, Malaga, Spain. The formation of plaques or spots where the phototrophic microorganisms disappeared can be assumed on the basis of processes of predation of bacteria, amoebas and some other organisms on the phototrophic biofilms. This study aims at investigating the potentialities of the biological control of phototrophic biofilms in caves, but the originality of these data should be confirmed in future studies with a larger number of biofilm samples in different ecological scenarios.

scholarly journals Architectural plasticity of AMPK revealed by electron microscopy and X-ray crystallography

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Yan Ouyang ◽  
Li Zhu ◽  
Yifang Li ◽  
Miaomiao Guo ◽  
Yang Liu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
X Ray ◽  
X Ray Crystallography ◽  
Architectural Plasticity

THE SUPER-TURING COMPUTATIONAL POWER OF PLASTIC RECURRENT NEURAL NETWORKS

2014 ◽  
Vol 24 (08) ◽  
pp. 1450029 ◽  
Author(s):  
JÉRÉMIE CABESSA ◽  
HAVA T. SIEGELMANN
Keyword(s):  
Neural Networks ◽  
Recurrent Neural Networks ◽  
Neural Model ◽  
Connectivity Pattern ◽  
General Mechanism ◽  
Computational Power ◽  
Biologically Inspired ◽  
Basic Model ◽  
Analog Neural Networks ◽  
Architectural Plasticity

We study the computational capabilities of a biologically inspired neural model where the synaptic weights, the connectivity pattern, and the number of neurons can evolve over time rather than stay static. Our study focuses on the mere concept of plasticity of the model so that the nature of the updates is assumed to be not constrained. In this context, we show that the so-called plastic recurrent neural networks (RNNs) are capable of the precise super-Turing computational power — as the static analog neural networks — irrespective of whether their synaptic weights are modeled by rational or real numbers, and moreover, irrespective of whether their patterns of plasticity are restricted to bi-valued updates or expressed by any other more general form of updating. Consequently, the incorporation of only bi-valued plastic capabilities in a basic model of RNNs suffices to break the Turing barrier and achieve the super-Turing level of computation. The consideration of more general mechanisms of architectural plasticity or of real synaptic weights does not further increase the capabilities of the networks. These results support the claim that the general mechanism of plasticity is crucially involved in the computational and dynamical capabilities of biological neural networks. They further show that the super-Turing level of computation reflects in a suitable way the capabilities of brain-like models of computation.

A flow-lane incubator for studying freshwater and marine phototrophic biofilms

2007 ◽  
Vol 70 (2) ◽  
pp. 336-345 ◽  
Author(s):  
Barbara Zippel ◽  
Jan Rijstenbil ◽  
Thomas R. Neu
Keyword(s):  
Phototrophic Biofilms

Kinetic modeling of phototrophic biofilms: The PHOBIA model

2007 ◽  
Vol 97 (5) ◽  
pp. 1064-1079 ◽  
Author(s):  
Gundula Wolf ◽  
Cristian Picioreanu ◽  
Mark C.M. van Loosdrecht
Keyword(s):  
Kinetic Modeling ◽  
Phototrophic Biofilms
Sign in / Sign up

Export Citation Format

Share Document