scholarly journals Biofilm growth mode promotes maximum carrying capacity and community stability during product inhibition syntrophy

2014 ◽  
Vol 5 ◽  
Author(s):  
Kristen A. Brileya ◽  
Laura B. Camilleri ◽  
Grant M. Zane ◽  
Judy D. Wall ◽  
Matthew W. Fields
Keyword(s):  
Carrying Capacity ◽  
Product Inhibition ◽  
Growth Mode ◽  
Community Stability ◽  
Biofilm Growth

scholarly journals Efficacy of carvacrol against resistant rapidly growing mycobacteria in the planktonic and biofilm growth mode

PLoS ONE ◽  
2019 ◽  
Vol 14 (7) ◽  
pp. e0219038 ◽  
Author(s):  
Emanuela Marini ◽  
Mara Di Giulio ◽  
Giovanna Ginestra ◽  
Gloria Magi ◽  
Silvia Di Lodovico ◽  
...  
Keyword(s):  
Growth Mode ◽  
Biofilm Growth ◽  
Rapidly Growing Mycobacteria

Carrying Capacity of Resources and Problems of Sustainable Development in Dongting Lake’s Flood Detention Basin

2014 ◽  
Vol 962-965 ◽  
pp. 1961-1964
Author(s):  
Yuan Jun Yu ◽  
Lin Wu
Keyword(s):  
Economic Growth ◽  
Sustainable Development ◽  
Population Growth ◽  
Carrying Capacity ◽  
Control Population ◽  
Growth Mode ◽  
Hunan Province ◽  
Dynamic Changes ◽  
Detention Basin ◽  
Economic Growth Mode

The relative carrying capacity of resources was used to analyze the dynamic changes of Dongting Lake’s flood detention basin. The relative carrying capacity of resources of flood detention basin compared with Hunan province from2004 to 2011 was calculated. The results shown that the flood detention basin is in population relatively surplus state, but its severe overloading in economy resources. The consultation was drawn as the economic compensation should be offer by downstream areas. Flood detention basin should transform economic growth mode, strict control population in resources lack and environmental vulnerability areas should be taken to reduce population growth pressures on resources.

scholarly journals NtrC Adds a New Node to the Complex Regulatory Network of Biofilm Formation andvpsExpression inVibrio cholerae

2018 ◽  
Vol 200 (15) ◽  
Author(s):  
Andrew T. Cheng ◽  
David Zamorano-Sánchez ◽  
Jennifer K. Teschler ◽  
Daniel Wu ◽  
Fitnat H. Yildiz
Keyword(s):  
Life Cycle ◽  
Vibrio Cholerae ◽  
Biofilm Formation ◽  
Nitrogen Availability ◽  
Nitrogen Sources ◽  
Growth Mode ◽  
Biofilm Growth ◽  
Content Type ◽  
Regulatory Systems

ABSTRACTThe biofilm growth mode is important in both the intestinal and environmental phases of theVibrio choleraelife cycle. Regulation of biofilm formation involves several transcriptional regulators and alternative sigma factors. One such factor is the alternative sigma factor RpoN, which positively regulates biofilm formation. RpoN requires bacterial enhancer-binding proteins (bEBPs) to initiate transcription. TheV. choleraegenome encodes seven bEBPs (LuxO, VC1522, VC1926 [DctD-1], FlrC, NtrC, VCA0142 [DctD-2], and PgtA) that belong to the NtrC family of response regulators (RRs) of two-component regulatory systems. The contribution of these regulators to biofilm formation is not well understood. In this study, we analyzed biofilm formation and the regulation ofvpsLexpression by RpoN activators. Mutants lacking NtrC had increased biofilm formation andvpsLexpression. NtrC negatively regulates the expression of core regulators of biofilm formation (vpsR,vpsT, andhapR). NtrC fromV. choleraesupported growth and activatedglnAexpression when nitrogen availability was limited. However, the repressive activity of NtrC towardvpsLexpression was not affected by the nitrogen sources present. This study unveils the role of NtrC as a regulator ofvpsexpression and biofilm formation inV. cholerae.IMPORTANCEBiofilms play an important role in theVibrio choleraelife cycle, contributing to both environmental survival and transmission to a human host. Identifying key regulators ofV. choleraebiofilm formation is necessary to fully understand how this important growth mode is modulated in response to various signals encountered in the environment and the host. In this study, we characterized the role of RRs that function as coactivators of RpoN in regulating biofilm formation and identified new components in theV. choleraebiofilm regulatory circuitry.

scholarly journals Biofilm Growth and Near-Infrared Radiation-Driven Photosynthesis of the Chlorophylld-Containing Cyanobacterium Acaryochloris marina

2012 ◽  
Vol 78 (11) ◽  
pp. 3896-3904 ◽  
Author(s):  
Lars Behrendt ◽  
Verena Schrameyer ◽  
Klaus Qvortrup ◽  
Luisa Lundin ◽  
Søren J. Sørensen ◽  
...  
Keyword(s):  
Blue Light ◽  
Infrared Radiation ◽  
Near Infrared ◽  
Growth Mode ◽  
Population Doubling ◽  
Near Infrared Radiation ◽  
Visible Radiation ◽  
Biofilm Growth ◽  
Content Type ◽  
Acaryochloris Marina

ABSTRACTThe cyanobacteriumAcaryochloris marinais the only known phototroph harboring chlorophyll (Chl)d. It is easy to cultivate it in a planktonic growth mode, andA. marinacultures have been subject to detailed biochemical and biophysical characterization. In natural situations,A. marinais mainly found associated with surfaces, but this growth mode has not been studied yet. Here, we show that theA. marinatype strain MBIC11017 inoculated into alginate beads forms dense biofilm-like cell clusters, as in naturalA. marinabiofilms, characterized by strong O2concentration gradients that change with irradiance. Biofilm growth under both visible radiation (VIS, 400 to 700 nm) and near-infrared radiation (NIR, ∼700 to 730 nm) yielded maximal cell-specific growth rates of 0.38 per day and 0.64 per day, respectively. The population doubling times were 1.09 and 1.82 days for NIR and visible light, respectively. The photosynthesis versus irradiance curves showed saturation at a photon irradiance ofEk(saturating irradiance) >250 μmol photons m−2s−1for blue light but no clear saturation at 365 μmol photons m−2s−1for NIR. The maximal gross photosynthesis rates in the aggregates were ∼1,272 μmol O2mg Chld−1h−1(NIR) and ∼1,128 μmol O2mg Chld−1h−1(VIS). The photosynthetic efficiency (α) values were higher in NIR-irradiated cells [(268 ± 0.29) × 10−6m2mg Chld−1(mean ± standard deviation)] than under blue light [(231 ± 0.22) × 10−6m2mg Chld−1].A. marinais well adapted to a biofilm growth mode under both visible and NIR irradiance and under O2conditions ranging from anoxia to hyperoxia, explaining its presence in natural niches with similar environmental conditions.

scholarly journals Cell Density Modulates Acid Adaptation in Streptococcus mutans: Implications for Survival in Biofilms

2001 ◽  
Vol 183 (23) ◽  
pp. 6875-6884 ◽  
Author(s):  
Yung-Hua Li ◽  
Michael N. Hanna ◽  
Gunnel Svensäter ◽  
Richard P. Ellen ◽  
Dennis G. Cvitkovitch
Keyword(s):  
Streptococcus Mutans ◽  
Cell Density ◽  
Culture Filtrate ◽  
High Cell Density ◽  
Acid Tolerance ◽  
Low Ph ◽  
Growth Mode ◽  
High Cell ◽  
Biofilm Growth ◽  
Acid Adaptation

ABSTRACT Streptococcus mutans normally colonizes dental biofilms and is regularly exposed to continual cycles of acidic pH during ingestion of fermentable dietary carbohydrates. The ability ofS. mutans to survive at low pH is an important virulence factor in the pathogenesis of dental caries. Despite a few studies of the acid adaptation mechanism of this organism, little work has focused on the acid tolerance of S. mutans growing in high-cell-density biofilms. It is unknown whether biofilm growth mode or high cell density affects acid adaptation by S. mutans. This study was initiated to examine the acid tolerance response (ATR) of S. mutans biofilm cells and to determine the effect of cell density on the induction of acid adaptation. S. mutans BM71 cells were first grown in broth cultures to examine acid adaptation associated with growth phase, cell density, carbon starvation, and induction by culture filtrates. The cells were also grown in a chemostat-based biofilm fermentor for biofilm formation. Adaptation of biofilm cells to low pH was established in the chemostat by the acid generated from excess glucose metabolism, followed by a pH 3.5 acid shock for 3 h. Both biofilm and planktonic cells were removed to assay percentages of survival. The results showed that S. mutans BM71 exhibited a log-phase ATR induced by low pH and a stationary-phase acid resistance induced by carbon starvation. Cell density was found to modulate acid adaptation in S. mutans log-phase cells, since pre-adapted cells at a higher cell density or from a dense biofilm displayed significantly higher resistance to the killing pH than the cells at a lower cell density. The log-phase ATR could also be induced by a neutralized culture filtrate collected from a low-pH culture, suggesting that the culture filtrate contained an extracellular induction component(s) involved in acid adaptation in S. mutans. Heat or proteinase treatment abolished the induction by the culture filtrate. The results also showed that mutants defective in thecomC, -D, or -E genes, which encode a quorum sensing system essential for cell density-dependent induction of genetic competence, had a diminished log-phase ATR. Addition of synthetic competence stimulating peptide (CSP) to the comC mutant restored the ATR. This study demonstrated that cell density and biofilm growth mode modulated acid adaptation in S. mutans, suggesting that optimal development of acid adaptation in this organism involves both low pH induction and cell-cell communication.

scholarly journals Growth Mode and Carbon Source Impact the Surfaceome Dynamics ofLactobacillus rhamnosusGG

2019 ◽  
Author(s):  
Kirsi Savijoki ◽  
Tuula A. Nyman ◽  
Veera Kainulainen ◽  
Ilkka Miettinen ◽  
Pia Siljamäki ◽  
...  
Keyword(s):  
Carbon Source ◽  
Lactobacillus Rhamnosus ◽  
Glycoside Hydrolases ◽  
Growth Mode ◽  
Aminopeptidase Activity ◽  
Carbohydrate Source ◽  
Biofilm Growth ◽  
Associated Proteins ◽  
Food Applications ◽  
Surface Adhesins

AbstractBacterial biofilms have clear implications in disease and in food applications involving probiotics. Here, we show that switching the carbohydrate source from glucose to fructose increased the biofilm formation and the total surface-antigenicity of a well-known probiotic,Lactobacillus rhamnosusGG. Surfaceomes (all cell surface-associated proteins) of GG cells grown with glucose and fructose in planktonic and biofilm cultures were identified and compared, which indicated carbohydrate source-dependent variations, especially during biofilm growth. The most distinctive differences under these conditions were detected with several surface adhesins (e.g., MBF, SpaC/A pilus and penicillin-binding proteins), enzymes (glycoside hydrolases, PrsA, PrtP, PrtR and HtrA) and moonlighting proteins (glycolytic, transcription/translation and stress-associated proteins, r-proteins, tRNA synthetases, Clp family proteins, PepC, PepN and PepA). The abundance of several known adhesins and novel moonlighters, including enzymes acting on casein-derived peptides (ClpP, PepC and PepN), increased in the biofilm cells grown on fructose, from which the surface-associated aminopeptidase activity mediated by PepC and PepN was further confirmed by an enzymatic assay. The classical surface adhesins were predicted to be more abundant on planktonic cells growing either on fructose (MBF and SpaA) or glucose (SpaC). An additional indirect ELISA indicated both growth mode- and carbohydrate-dependent differences in abundance of SpaC, whereas the overall adherence of GG assessed with porcine mucus indicated that the carbon source and the growth mode affected mucus adhesion. The adherence of GG cells to mucus was almost completely inhibited by anti-SpaC antibodies regardless of growth mode and/or carbohydrate source, indicating the key role of the SpaCBA pilus in adherence under the tested conditions. Altogether, our results suggest that carbon source and growth mode coordinate classical and nonclassical protein export in GG, which ensures the presence of an integral and coordinated system that contributes to resistance, nutrient acquisition and cell-cell interactions under different conditions. In conclusion, the present study shows that different growth regimes and conditions can have a profound impact on the adherent and antigenic features of GG, thereby providing new information on how to gain additional benefits from this probiotic.

Analisis Daya Dukung Tanah Dan Bahan Pondasi Tiang Pancang Pada Pembangunan Jembatan Kab. Jombang

2020 ◽  
Vol 9 (1) ◽  
pp. 32-37
Author(s):  
Ruslan Hidayat ◽  
Saiful Arfaah
Keyword(s):  
Carrying Capacity ◽  
Pile Foundation ◽  
Heavy Traffic ◽  
Traffic Volume ◽  
Material Strength ◽  
Cone Penetrometer ◽  
The Village

One of the most important factors in the structure of the pile foundation in the construction of the bridge is the carrying capacity of the soil so as not to collapse. Construction of a bridge in the village of Klitik in Jombang Regency to be built due to heavy traffic volume. The foundation plan to be used is a pile foundation with a diameter of 50 cm, the problem is what is the value of carrying capacity of soil and material. The equipment used is the Dutch Cone Penetrometer with a capacity of 2.50 tons with an Adhesion Jacket Cone. The detailed specifications of this sondir are as follows: Area conus 10 cm², piston area 10 cm², coat area 100 cm², as for the results obtained The carrying capacity of the soil is 60.00 tons for a diameter of 30 cm, 81,667 tons for a diameter of 35 cm, 106,667 tons for a diameter of 40 cm, 150,000 tons for a diameter of 50 cm for material strength of 54,00 tons for a diameter of 30 cm, 73,500 tons for a diameter of 35 cm, 96,00 tons for a diameter of 40 cm, 166,666 tons for a diameter of 50 cm

Agroforestry in Eastern Otago: results from two long-term experiments

2000 ◽  
pp. 93-98
Author(s):  
G.G. Cossens ◽  
M.F. Hawke
Keyword(s):  
Soil Ph ◽  
Tree Growth ◽  
Pinus Radiata ◽  
Carrying Capacity ◽  
Livestock Grazing ◽  
Tree Age ◽  
Rapid Decline ◽  
Pasture Production ◽  
Clover Content ◽  
Pasture Yield

During the first 20 years of a Pinus radiata tree rotation, tree growth and pasture yield were assessed under a range of tree spacings at Invermay and Akatore, two coastal sites in Eastern Otago. Pasture yield in association with trees thinned to 100 stems per hectare (sph) was comparable to that from open pasture up to a tree age of 12 years. By the 19th year, however, pasture production declined to 63% of open pasture yield at Invermay and to 42% at Akatore. At 200 and 400 sph at Akatore, pasture yield was similar to that from open pasture at tree age 12 years but declined to 27% and 0% of open pasture yield respectively by year 20. At both Invermay and Akatore, the ryegrass and clover content of open pasture was relatively constant throughout the term of the trial. However, both the ryegrass and clover content of pasture beneath trees began to decline by tree age 12 years with a very rapid decline at Akatore in the number of pasture species at 200 sph by the 19th year. No pasture remained at 400 sph, after 19 years. Livestock carrying capacity with sheep on tree treatments at Invermay decreased from 100% of open pasture at year 6 to 60% by year 10. At Akatore, livestock carrying capacity averaged over the 20-year life of the trial was 4.1 stock units per hectare with a maximum of 8.1 stock units at a tree age of 8 years. Tree growth at both sites was similar, averaging between 1 and 1.1 m/year in height over 20 years, with trees at Invermay at 100 sph averaging 9% greater height and diameter growth than at Akatore. Increasing tree stocking from 100 to 200 to 400 sph at Akatore, resulted in increased tree height, but decreased diameter at breast height. A comparison of the East Otago trees with those in a similar trial at Tikitere (Rotorua) 900 km further north indicated that the southern trees were about 6 years later in their growth pattern by tree age 20 years. On both sites, soil pH tended to be lower in the presence of trees and was significantly lower than in open pasture by year 20. The results and comparisons with the Tikitere data suggest that, in an integrated agroforestry regime, there will be livestock grazing under the trees further into the tree rotation in Otago than in North Island sites. However, slower tree growth would result in a longer rotation time to harvest. Current recommendations to farmers are to plant trees on the less productive areas of the farm and adopt a tree stocking rate which fully utilises the site. Keywords: agroforestry, livestock, pasture, Pinus radiata, soil pH, tree stocking

THE CLASSIFICATION OF LAND ACCORDING TO THE DEGREE OF RABBIT INFESTATION IN CENTRAL OTAGO

1987 ◽  
pp. 65-70
Author(s):  
I.G.C. Kerr ◽  
J.M. Williams ◽  
W.D. Ross ◽  
J.M. Pollard
Keyword(s):  
Carrying Capacity ◽  
Mediterranean Climate ◽  
Natural Habitat ◽  
Public Funding ◽  
Soil Survey ◽  
European Rabbit ◽  
Cultural Modification ◽  
Classification Information ◽  
Semi Arid

The European rabbit (Oryctolagus cuniculus) introduced into New Zealand in the 183Os, has consistently flourished in Central Otago, the upper Waitaki, and inland Marlborough, all areas of mediterranean climate. It has proved difficult to manage in these habitats. The 'rabbit problem' is largely confined to 105,000 ha of low producing land mostly in semi arid areas of Central Otago. No field scale modifications of the natural habitat have been successful in limiting rabbit numbers. The costs of control exceed the revenue from the land and continued public funding for control operations appears necessary. A system for classifying land according to the degree of rabbit proneness is described. Soil survey and land classification information for Central Otago is related to the distribution and density of rabbits. This intormation can be used as a basis for defining rabbit carrying capacity and consequent land use constraints and management needs. It is concluded that the natural rabbit carrying capacity of land can be defined by reference to soil survey information and cultural modification to the natural vegetation. Classification of land according to rabbit proneness is proposed as a means of identifying the need for, and allocation of, public funding tor rabbit management. Keywords: Rabbit habitat, rabbit proneness, use of rabbit prone land.

PASTURE ESTABLISHMENT ON EAST COAST NORTH ISLAND HILL COUNTRY

1984 ◽  
pp. 216-218
Author(s):  
B.J. Arnst ◽  
O.L. Park
Keyword(s):  
White Clover ◽  
Carrying Capacity ◽  
Return On Investment ◽  
East Coast ◽  
Close Association ◽  
Development Programme ◽  
Low Fertility ◽  
Stock Management ◽  
Hill Country

Large areas of North Island hill country are producing below potential as a result of low fertility and poor pasture composition. Removal of undesirable species and replacement with a higher producing pasture is essential for increased productivity but is difficult to achieve. A development programme is described where the use of glyphosate in close association with oversowing and stock management has allowed rapid pasture establishment, marked increase in carrying capacity and a quick return on investment. Keywords: Pasture establishment, glyphosate, oversowing, white clover, subdivision, productivity.

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