scholarly journals Development of Spatial Distribution Patterns by Biofilm Cells

2015 ◽  
Vol 81 (18) ◽  
pp. 6120-6128 ◽  
Author(s):  
Janus A. J. Haagensen ◽  
Susse K. Hansen ◽  
Bjarke B. Christensen ◽  
Sünje J. Pamp ◽  
Søren Molin
Keyword(s):  
Spatial Pattern ◽  
Species Distribution ◽  
Spatial Organization ◽  
Microbial Mats ◽  
Distribution Patterns ◽  
Time Lapse ◽  
Historical Contingency ◽  
Water Stream ◽  
Content Type ◽  
Microbial Distribution

ABSTRACTConfined spatial patterns of microbial distribution are prevalent in nature, such as in microbial mats, soil communities, and water stream biofilms. The symbiotic two-species consortium ofPseudomonas putidaandAcinetobactersp. strain C6, originally isolated from a creosote-polluted aquifer, has evolved a distinct spatial organization in the laboratory that is characterized by an increased fitness and productivity. In this consortium,P. putidais reliant on microcolonies formed byAcinetobactersp. C6, to which it attaches. Here we describe the processes that lead to the microcolony pattern byAcinetobactersp. C6. Ecological spatial pattern analyses revealed that the microcolonies were not entirely randomly distributed and instead were arranged in a uniform pattern. Detailed time-lapse confocal microscopy at the single-cell level demonstrated that the spatial pattern was the result of an intriguing self-organization: small multicellular clusters moved along the surface to fuse with one another to form microcolonies. This active distribution capability was dependent on environmental factors (carbon source and oxygen) and historical contingency (formation of phenotypic variants). The findings of this study are discussed in the context of species distribution patterns observed in macroecology, and we summarize observations about the processes involved in coadaptation betweenP. putidaandAcinetobactersp. C6. Our results contribute to an understanding of spatial species distribution patterns as they are observed in nature, as well as the ecology of engineered communities that have the potential for enhanced and sustainable bioprocessing capacity.

scholarly journals Cellular Architecture Mediates DivIVA Ultrastructure and Regulates Min Activity in Bacillus subtilis

mBio ◽  
2011 ◽  
Vol 2 (6) ◽  
Author(s):  
Prahathees Eswaramoorthy ◽  
Marcella L. Erb ◽  
James A. Gregory ◽  
Jared Silverman ◽  
Kit Pogliano ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Cell Division ◽  
Spatial Organization ◽  
Time Lapse ◽  
Structured Illumination ◽  
Structured Illumination Microscopy ◽  
Content Type ◽  
Temporal Regulation ◽  
Min Proteins

ABSTRACTThe assembly of the cell division machinery at midcell is a critical step of cytokinesis. Many rod-shaped bacteria position septa using nucleoid occlusion, which prevents division over the chromosome, and the Min system, which prevents division near the poles. Here we examined thein vivoassembly of theBacillus subtilisMinCD targeting proteins DivIVA, a peripheral membrane protein that preferentially localizes to negatively curved membranes and resembles eukaryotic tropomyosins, and MinJ, which recruits MinCD to DivIVA. We used structured illumination microscopy to demonstrate that both DivIVA and MinJ localize as double rings that flank the septum and first appear early in septal biosynthesis. The subsequent recruitment of MinCD to these double rings would separate the Min proteins from their target, FtsZ, spatially regulating Min activity and allowing continued cell division. Curvature-based localization would also provide temporal regulation, since DivIVA and the Min proteins would localize to midcell after the onset of division. We use time-lapse microscopy and fluorescence recovery after photobleaching to demonstrate that DivIVA rings are highly stable and are constructed from newly synthesized DivIVA molecules. After cell division, DivIVA rings appear to collapse into patches at the rounded cell poles of separated cells, with little or no incorporation of newly synthesized subunits. Thus, changes in cell architecture mediate both the initial recruitment of DivIVA to sites of cell division and the subsequent collapse of these rings into patches (or rings of smaller diameter), while curvature-based localization of DivIVA spatially and temporally regulates Min activity.IMPORTANCEThe Min systems ofEscherichia coliandBacillus subtilisboth inhibit FtsZ assembly, but one key difference between these two species is that whereas theE. coliMin proteins localize to the poles, theB. subtilisproteins localize to nascent division sites by interaction with DivIVA and MinJ. It is unclear how MinC activity at midcell is regulated to prevent it from interfering with FtsZ engaged in medial cell division. We used superresolution microscopy to demonstrate that DivIVA and MinJ, which localize MinCD, assemble double rings that flank active division sites and septa. This curvature-based localization mechanism holds MinCD away from the FtsZ ring at midcell, and we propose that this spatial organization is the primary mechanism by which MinC activity is regulated to allow division at midcell. Curvature-based localization also conveys temporal regulation, since it ensures that MinC localizes after the onset of division.

scholarly journals Fine-Scale Distribution Patterns of Synechococcus Ecological Diversity in Microbial Mats of Mushroom Spring, Yellowstone National Park

2011 ◽  
Vol 77 (21) ◽  
pp. 7689-7697 ◽  
Author(s):  
Eric D. Becraft ◽  
Frederick M. Cohan ◽  
Michael Kühl ◽  
Sheila I. Jensen ◽  
David M. Ward
Keyword(s):  
Microbial Mats ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Pcr Amplification ◽  
Photosynthetic Reaction Center ◽  
Distribution Patterns ◽  
Spectral Irradiance ◽  
Sequence Variants ◽  
Content Type ◽  
Habitat Variation ◽  
Gradient Gel Electrophoresis

ABSTRACTPast analyses of sequence diversity in high-resolution protein-encoding genes have identified putative ecological species of unicellular cyanobacteria in the genusSynechococcus, which are specialized to 60°C but not 65°C in Mushroom Spring microbial mats. Because these studies were limited to only two habitats, we studied the distribution ofSynechococcussequence variants at 1°C intervals along the effluent flow channel and at 80-μm vertical-depth intervals throughout the upper photic layer of the microbial mat. Diversity at thepsaAlocus, which encodes a photosynthetic reaction center protein (PsaA), was sampled by PCR amplification, cloning, and sequencing methods at 60, 63, and 65°C sites. The evolutionary simulation programs Ecotype Simulation and AdaptML were used to identify putative ecologically distinct populations (ecotypes). Ecotype Simulation predicted a higher number of putative ecotypes in cases where habitat variation was limited, while AdaptML predicted a higher number of ecologically distinct phylogenetic clades in cases where habitat variation was high. Denaturing gradient gel electrophoresis was used to track the distribution of dominant sequence variants of ecotype populations relative to temperature variation and to O2, pH, and spectral irradiance variation, as measured using microsensors. Different distributions along effluent channel flow and vertical gradients, where temperature, light, and O2concentrations are known to vary, confirmed the ecological distinctness of putative ecotypes.

Vegetation dynamics and species distribution patterns in the inland desert wadis of South Sinai, Egypt

2013 ◽  
Vol 39 (2) ◽  
pp. 93-110
Author(s):  
Fawzy M. Salama ◽  
Monier Abd El-Ghani ◽  
Salah El Naggar ◽  
Mohamed Aljarroushi
Keyword(s):  
Species Distribution ◽  
Vegetation Dynamics ◽  
Distribution Patterns ◽  
South Sinai

Levels of Spatial Variability: The “Community” Problem

1990 ◽  
Vol 5 ◽  
pp. 13-30 ◽  
Author(s):  
D. A. Springer ◽  
A. I. Miller
Keyword(s):  
Community Structure ◽  
Spatial Variability ◽  
Species Distribution ◽  
Distribution Patterns ◽  
The Past ◽  
Structure And Dynamics ◽  
Evolutionary Units ◽  
The Way

The way we view species distribution patterns, particularly at the level commonly referred to as the “community”, has changed over the past 70 years in biology and, subsequently, in paleontology. Because the degree to which species associations can be interpreted as ecological and evolutionary units depends ultimately on recognition and interpretation of faunal spatial variability, we need to understand the nature of this variability at all levels of resolution before we can adequately address questions of “community” structure and dynamics. While it is possible to recognize spatial variability at several levels, from the distributions of individuals within a species to the overall pattern created by the global biota, we must ask whether these patterns really comprise a hierarchy with natural discontinuities (Fig. 1), or whether it is more realistic to view them as a continuous variability spectrum.

scholarly journals Imaging and Analysis of Pseudomonas aeruginosa Swarming and Rhamnolipid Production

2011 ◽  
Vol 77 (23) ◽  
pp. 8310-8317 ◽  
Author(s):  
Joshua D. Morris ◽  
Jessica L. Hewitt ◽  
Lawrence G. Wolfe ◽  
Nachiket G. Kamatkar ◽  
Sarah M. Chapman ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Fluorescent Protein ◽  
Nile Red ◽  
Temporal Distribution ◽  
Time Lapse ◽  
Content Type ◽  
Rhamnolipid Production ◽  
Serovar Typhimurium ◽  
Surface Motility ◽  
Green Fluorescent

ABSTRACTMany bacteria spread over surfaces by “swarming” in groups. A problem for scientists who study swarming is the acquisition of statistically significant data that distinguish two observations or detail the temporal patterns and two-dimensional heterogeneities that occur. It is currently difficult to quantify differences between observed swarm phenotypes. Here, we present a method for acquisition of temporal surface motility data using time-lapse fluorescence and bioluminescence imaging. We specifically demonstrate three applications of our technique with the bacteriumPseudomonas aeruginosa. First, we quantify the temporal distribution ofP. aeruginosacells tagged with green fluorescent protein (GFP) and the surfactant rhamnolipid stained with the lipid dye Nile red. Second, we distinguish swarming ofP. aeruginosaandSalmonella entericaserovar Typhimurium in a coswarming experiment. Lastly, we quantify differences in swarming and rhamnolipid production of severalP. aeruginosastrains. While the best swarming strains produced the most rhamnolipid on surfaces, planktonic culture rhamnolipid production did not correlate with surface growth rhamnolipid production.

scholarly journals Stochasticity in Colonial Growth Dynamics of Individual Bacterial Cells

2013 ◽  
Vol 79 (7) ◽  
pp. 2294-2301 ◽  
Author(s):  
Konstantinos P. Koutsoumanis ◽  
Alexandra Lianou
Keyword(s):  
Kinetic Parameters ◽  
Single Cells ◽  
Growth Curves ◽  
Growth Dynamics ◽  
Time Lapse ◽  
Initial Population ◽  
Bacterial Cells ◽  
Stochastic Growth ◽  
Bacterial Populations ◽  
Content Type

ABSTRACTConventional bacterial growth studies rely on large bacterial populations without considering the individual cells. Individual cells, however, can exhibit marked behavioral heterogeneity. Here, we present experimental observations on the colonial growth of 220 individual cells ofSalmonella entericaserotype Typhimurium using time-lapse microscopy videos. We found a highly heterogeneous behavior. Some cells did not grow, showing filamentation or lysis before division. Cells that were able to grow and form microcolonies showed highly diverse growth dynamics. The quality of the videos allowed for counting the cells over time and estimating the kinetic parameters lag time (λ) and maximum specific growth rate (μmax) for each microcolony originating from a single cell. To interpret the observations, the variability of the kinetic parameters was characterized using appropriate probability distributions and introduced to a stochastic model that allows for taking into account heterogeneity using Monte Carlo simulation. The model provides stochastic growth curves demonstrating that growth of single cells or small microbial populations is a pool of events each one of which has its own probability to occur. Simulations of the model illustrated how the apparent variability in population growth gradually decreases with increasing initial population size (N0). For bacterial populations withN0of >100 cells, the variability is almost eliminated and the system seems to behave deterministically, even though the underlying law is stochastic. We also used the model to demonstrate the effect of the presence and extent of a nongrowing population fraction on the stochastic growth of bacterial populations.

scholarly journals Why Orange Guaymas Basin Beggiatoa spp. Are Orange: Single-Filament-Genome-Enabled Identification of an Abundant Octaheme Cytochrome with Hydroxylamine Oxidase, Hydrazine Oxidase, and Nitrite Reductase Activities

2012 ◽  
Vol 79 (4) ◽  
pp. 1183-1190 ◽  
Author(s):  
Barbara J. MacGregor ◽  
Jennifer F. Biddle ◽  
Jason R. Siebert ◽  
Eric Staunton ◽  
Eric L. Hegg ◽  
...  
Keyword(s):  
Nitrite Reductase ◽  
Pure Culture ◽  
Gulf Of California ◽  
Microbial Mats ◽  
Physiological Role ◽  
Nitrite Reduction ◽  
Cold Seeps ◽  
Single Filament ◽  
Guaymas Basin ◽  
Content Type

ABSTRACTOrange, white, and yellow vacuolatedBeggiatoaceaefilaments are visually dominant members of microbial mats found near sea floor hydrothermal vents and cold seeps, with orange filaments typically concentrated toward the mat centers. No marine vacuolateBeggiatoaceaeare yet in pure culture, but evidence to date suggests they are nitrate-reducing, sulfide-oxidizing bacteria. The nearly complete genome sequence of a single orangeBeggiatoa(“CandidatusMaribeggiatoa”) filament from a microbial mat sample collected in 2008 at a hydrothermal site in Guaymas Basin (Gulf of California, Mexico) was recently obtained. From this sequence, the gene encoding an abundant soluble orange-pigmented protein in Guaymas Basin mat samples (collected in 2009) was identified by microcapillary reverse-phase high-performance liquid chromatography (HPLC) nano-electrospray tandem mass spectrometry (μLC–MS-MS) of a pigmented band excised from a denaturing polyacrylamide gel. The predicted protein sequence is related to a large group of octaheme cytochromes whose few characterized representatives are hydroxylamine or hydrazine oxidases. The protein was partially purified and shown byin vitroassays to have hydroxylamine oxidase, hydrazine oxidase, and nitrite reductase activities. From what is known ofBeggiatoaceaephysiology, nitrite reduction is the most likelyin vivorole of the octaheme protein, but future experiments are required to confirm this tentative conclusion. Thus, while present-day genomic and proteomic techniques have allowed precise identification of an abundant mat protein, and its potential activities could be assayed, proof of its physiological role remains elusive in the absence of a pure culture that can be genetically manipulated.

The tradeoff between fit perceptions across recruitment stages by new job seekers

2017 ◽  
Vol 29 (10) ◽  
pp. 2610-2628 ◽  
Author(s):  
Chih-Lun (Alan) Yen
Keyword(s):  
Empirical Support ◽  
Time Lapse ◽  
Job Choice ◽  
Job Seekers ◽  
Recruitment Process ◽  
Content Type ◽  
Face To Face ◽  
Tourism Management ◽  
The Difference ◽  
Recruitment Stages

Purpose The purpose of this study is to explore the tradeoff between person-job (PJ) fit and person-organization (PO) fit by new job seekers across different recruitment stages and the influence on their job choice decisions. Design/methodology/approach A time-lapse research design was adopted with data from a survey over a two-year period of college students majoring in hospitality and tourism management at different recruitment stages (i.e. generating applications, maintaining applicant status and making a job choice). Findings The results suggest that PJ fit has a stronger influence on job choice decisions than PO fit, and both fit perceptions are consistent across recruitment stages. However, the difference between the two fit perceptions may be affected by direct interactions with recruiters at career fairs and interviews. Practical implications When recruiters start interacting with job seekers during the initial stage of the recruitment process, the recruiters are more likely to receive a favorable job choice decision from these potential applicants. Additionally, recruiters should create a positive perception of hiring companies and jobs through career fairs or other face-to-face communications to keep job seekers interested and maintain their applicant status throughout the recruitment stages. Originality/value This paper explores important factors that influence job seekers’ job choice decisions throughout the recruitment process with three main stages, which provides a more holistic overview of the transition of job seekers’ fit perceptions of the job and the organization. It also provides empirical support for current understanding of recruitment issues in the hospitality industry.

scholarly journals Vineyard ecosystems are structured and distinguished by fungal communities impacting the flavour and quality of wine

2019 ◽  
Author(s):  
Di Liu ◽  
Qinglin Chen ◽  
Pangzhen Zhang ◽  
Deli Chen ◽  
Kate S. Howell
Keyword(s):  
Regional Distribution ◽  
Distribution Patterns ◽  
Wine Fermentation ◽  
Fungal Communities ◽  
Soil Microbiome ◽  
Soil Conditions ◽  
Wine Aroma ◽  
Wine Production ◽  
Microbial Distribution

AbstractThe flavours of foods and beverages are formed by the agricultural environment where the plants are grown. In the case of wine, the location and environmental features of the vineyard site imprint the wine with distinctive aromas and flavours. Microbial growth and metabolism play an integral role in wine production from the vineyard to the winery, by influencing grapevine health, wine fermentation, and the flavour, aroma and quality of finished wines. The mechanism by which microbial distribution patterns drive wine metabolites is unclear and while flavour has been correlated with bacterial composition for red wines, bacterial activity provides a minor biochemical conversion in wine fermentation. Here, we collected samples across six distinct winegrowing areas in southern Australia to investigate regional distribution patterns of both fungi and bacteria and how this corresponds with wine aroma compounds. Results show that soil and must microbiota distinguish winegrowing regions and are related to wine chemical profiles. We found a strong relationship between microbial and wine metabolic profiles, and this relationship was maintained despite differing abiotic drivers (soil properties and weather/ climatic measures). Notably, fungal communities played the principal role in shaping wine aroma profiles and regional distinctiveness. We found that the soil microbiome is a potential source of grape- and must-associated fungi, and therefore the weather and soil conditions could influence the wine characteristics via shaping the soil fungal community compositions. Our study describes a comprehensive scenario of wine microbial biogeography in which microbial diversity responds to surrounding environments and ultimately sculpts wine aromatic characteristics. These findings provide perspectives for thoughtful human practices to optimise food and beverage flavour and composition through understanding of fungal activity and abundance.

Sign in / Sign up

Export Citation Format

Share Document