scholarly journals Specific mechanism of Acidithiobacillus caldus extracellular polymeric substances in the bioleaching of copper-bearing sulfide ore

PLoS ONE ◽  
2019 ◽  
Vol 14 (4) ◽  
pp. e0213945 ◽  
Author(s):  
Shoushuai Feng ◽  
Kaijun Li ◽  
Zhuangzhuang Huang ◽  
Yanjun Tong ◽  
Hailin Yang
Keyword(s):  
Extracellular Polymeric Substances ◽  
Specific Mechanism ◽  
Acidithiobacillus Caldus ◽  
Sulfide Ore

Process Description of an Unconventional Biofilm Formation by Bacterial Cells Autoagglutinating Through Sticky, Long, and Peritrichate Nanofibers

2019 ◽  
Author(s):  
Yoshihide Furuichi ◽  
Shogo Yoshimoto ◽  
Tomohiro Inaba ◽  
Nobuhiko Nomura ◽  
Katsutoshi Hori
Keyword(s):  
Formation Process ◽  
Biofilm Formation ◽  
Extracellular Polymeric Substances ◽  
Waste Treatment ◽  
Large Cell ◽  
Dlvo Theory ◽  
Bacterial Cells ◽  
Chemical Production ◽  
Discontinuous Surface ◽  
Cell Cell

<p></p><p>Biofilms are used in environmental biotechnologies including waste treatment and environmentally friendly chemical production. Understanding the mechanisms of biofilm formation is essential to control microbial behavior and improve environmental biotechnologies. <i>Acinetobacter </i>sp. Tol 5 autoagglutinate through the interaction of the long, peritrichate nanofiber protein AtaA, a trimeric autotransporter adhesin. Using AtaA, without cell growth or the production of extracellular polymeric substances, Tol 5 cells quickly form an unconventional biofilm. In this study, we investigated the formation process of this unconventional biofilm, which started with cell–cell interactions, proceeded to cell clumping, and led to the formation of large cell aggregates. The cell–cell interaction was described by DLVO theory based on a new concept, which considers two independent interactions between two cell bodies and between two AtaA fiber tips forming a virtual discontinuous surface. If cell bodies cannot collide owing to an energy barrier at low ionic strengths but approach within the interactive distance of AtaA fibers, cells can agglutinate through their contact. Cell clumping proceeds following the cluster–cluster aggregation model, and an unconventional biofilm containing void spaces and a fractal nature develops. Understanding its formation process would extend the utilization of various types of biofilms, enhancing environmental biotechnologies.</p><p></p>

A Matter of Perspective: How adults represent causal launching sequences

2020 ◽  
Author(s):  
Deon T. Benton ◽  
David H. Rakison
Keyword(s):  
Specific Mechanism ◽  
Associative Mechanism ◽  
Low Level ◽  
Domain Specific ◽  
The World ◽  
Modular Domain ◽  
Stimulus Features

The ability to reason about causal events in the world is fundamental to cognition. Despite the importance of this ability, little is known about how adults represent causal events, what structure or form those representations take, and what the mechanism is that underpins such representations. We report four experiments with adults that examine the perceptual basis on which adults represent four-object launching sequences (Experiments 1 and 2), whether adults representations reflect sensitivity to the causal, perceptual, or causal and perceptual relation among the objects that comprise such sequences (Experiment 3), and whether such representations extend beyond spatiotemporal contiguity to include other low-level stimulus features such as an object’s shape and color (Experiment 4). Based on these results of the four experiments, we argue that a domain-general associative mechanism, rather a modular, domain-specific, mechanism subserves adults’ representations of four-object launching sequences.

Filtration resistance induced by ammonia oxidizers accumulating on the rotating membrane disk

1998 ◽  
Vol 38 (4-5) ◽  
pp. 443-452
Author(s):  
Katsuki Kimura ◽  
Yoshimasa Watanabe ◽  
Naoki Ohkuma
Keyword(s):  
Membrane Filtration ◽  
Extracellular Polymeric Substances ◽  
Drinking Water Treatment ◽  
Treatment Method ◽  
Operating Conditions ◽  
Transmembrane Pressure ◽  
Ammonia Oxidizers ◽  
Filtration Resistance ◽  
Rotating Membrane Disk ◽  
Membrane Disk

Membrane filtration and oxidation of ammonia were simultaneously performed by using a rotating membrane disk module. Nitrification performance, composition of the accumulated cakes on the membrane and the filtration resistances were investigated under five different operating conditions. The filtration resistance due to the accumulated cake on the membrane was found to be dominant in this treatment method, compared to the resistance due to the micropore plugging or irreversible adherence. The cake consisted mainly of iron, humic substances and bacteria. The possibility that extracellular polymeric substances were related to the cake resistance was also shown. The composition of the cake depended on the length and the condition of operation. Accumulation of ammonia oxidizers caused by oxidation of low concentrations of ammonia (less than 1 mg/l) did not increase transmembrane pressure significantly. Therefore, the application of this treatment method for drinking water treatment is feasible. Filtration resistance due to the micropore plugging or irreversible adherence to the membrane was caused by organic substances.

Antibiotics Application Strategies to Control Biofilm Formation in Pathogenic Bacteria

2020 ◽  
Vol 21 (4) ◽  
pp. 270-286 ◽  
Author(s):  
Fazlurrahman Khan ◽  
Dung T.N. Pham ◽  
Sandra F. Oloketuyi ◽  
Young-Mog Kim
Keyword(s):  
Biofilm Formation ◽  
Pathogenic Bacteria ◽  
Extracellular Polymeric Substances ◽  
Quorum Quenching ◽  
Resistance Mechanisms ◽  
Bacterial Biofilm ◽  
Bacterial Cells ◽  
High Concentration ◽  
Biofilm Inhibition ◽  
Abiotic Surfaces

Background: The establishment of a biofilm by most pathogenic bacteria has been known as one of the resistance mechanisms against antibiotics. A biofilm is a structural component where the bacterial community adheres to the biotic or abiotic surfaces by the help of Extracellular Polymeric Substances (EPS) produced by bacterial cells. The biofilm matrix possesses the ability to resist several adverse environmental factors, including the effect of antibiotics. Therefore, the resistance of bacterial biofilm-forming cells could be increased up to 1000 times than the planktonic cells, hence requiring a significantly high concentration of antibiotics for treatment. Methods: Up to the present, several methodologies employing antibiotics as an anti-biofilm, antivirulence or quorum quenching agent have been developed for biofilm inhibition and eradication of a pre-formed mature biofilm. Results: Among the anti-biofilm strategies being tested, the sub-minimal inhibitory concentration of several antibiotics either alone or in combination has been shown to inhibit biofilm formation and down-regulate the production of virulence factors. The combinatorial strategies include (1) combination of multiple antibiotics, (2) combination of antibiotics with non-antibiotic agents and (3) loading of antibiotics onto a carrier. Conclusion: The present review paper describes the role of several antibiotics as biofilm inhibitors and also the alternative strategies adopted for applications in eradicating and inhibiting the formation of biofilm by pathogenic bacteria.

The roles of extracellular polymeric substances of Pandoraea sp. XY-2 in the removal of tetracycline

2020 ◽  
Vol 43 (11) ◽  
pp. 1951-1960
Author(s):  
Xueling Wu ◽  
Xiaoyan Wu ◽  
Xiangyu Zhou ◽  
Yichao Gu ◽  
Han Zhou ◽  
...  
Keyword(s):  
Extracellular Polymeric Substances

scholarly journals Biofilm Formation in Xanthomonas arboricola pv. pruni: Structure and Development

Agronomy ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 546
Author(s):  
Pilar Sabuquillo ◽  
Jaime Cubero
Keyword(s):  
Biofilm Formation ◽  
Extracellular Polymeric Substances ◽  
Environmental Changes ◽  
Nutrient Content ◽  
Infection Process ◽  
Bacterial Attachment ◽  
Key Factors ◽  
Cell Structures ◽  
Microscopy Techniques

Xanthomonasarboricola pv. pruni (Xap) causes bacterial spot of stone fruit and almond, an important plant disease with a high economic impact. Biofilm formation is one of the mechanisms that microbial communities use to adapt to environmental changes and to survive and colonize plants. Herein, biofilm formation by Xap was analyzed on abiotic and biotic surfaces using different microscopy techniques which allowed characterization of the different biofilm stages compared to the planktonic condition. All Xap strains assayed were able to form real biofilms creating organized structures comprised by viable cells. Xap in biofilms differentiated from free-living bacteria forming complex matrix-encased multicellular structures which become surrounded by a network of extracellular polymeric substances (EPS). Moreover, nutrient content of the environment and bacterial growth have been shown as key factors for biofilm formation and its development. Besides, this is the first work where different cell structures involved in bacterial attachment and aggregation have been identified during Xap biofilm progression. Our findings provide insights regarding different aspects of the biofilm formation of Xap which improve our understanding of the bacterial infection process occurred in Prunus spp and that may help in future disease control approaches.

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