Investigation of the ability of Francisella tularensis strains to form biofilms

2021 ◽  
pp. 69
Author(s):  
Kseniya Viktorovna Naumova ◽  
Andrey Vladimirovich Mazepa ◽  
Ayuna Konstantinovna Syngeeva ◽  
Elena Stanislavovna Kulikalova
Keyword(s):  
Qualitative Analysis ◽  
Francisella Tularensis ◽  
Biofilm Formation ◽  
Substrate Surface ◽  
Culture Conditions ◽  
Optimal Conditions ◽  
Study Results

The study results of the Francisella tularensis stains’ ability to form biofilm on the substrate surface are presented. The qualitative analysis of biofilm forming in the different culture conditions at the surface of glass vials has been performed. It was shown that all studied strains could form a biofilm, but most optimal conditions for biofilm formation are temperature at 22 ± 1 °C and culture exposition during 192 hours.

Fabrication and Properties Study of the Dielectric Membranes Used as Constructive Basis for Sensitive Elements of Gas Sensors

2015 ◽  
Vol 799-800 ◽  
pp. 994-997 ◽  
Author(s):  
Denis Veselov
Keyword(s):  
Magnetron Sputtering ◽  
Qualitative Analysis ◽  
Gas Sensors ◽  
Silicon Oxide ◽  
Alkaline Solutions ◽  
Reactive Magnetron ◽  
Membrane Structures ◽  
Two Stage ◽  
Study Results ◽  
Semiconductor Gas Sensors

The article presents the properties study results of the dielectric membranes for sensitive elements of semiconductor gas sensors, obtained by different modes of the reactive magnetron sputtering of silicon with application of the two-stage unilateral anisotropic etching of silicon in the organic alkaline solutions. The qualitative analysis of the membranes stability to destructions and deformations in the course of their fabrication and heating is given. Optimum structures and modes of films formation for dielectric membrane structures are determined. The admissible thickness of the thermal silicon oxide underlay, which is does not promote to considerable membranes deformations in the course of their fabrication and heating, is identified.

scholarly journals Evaluation of Morphological Changes of <i>Aeromonas caviae</i> Sch3 Biofilm Formation under Optimal Conditions

2012 ◽  
Vol 02 (04) ◽  
pp. 552-560 ◽  
Author(s):  
Erika Beatriz Angeles-Morales ◽  
Ricardo Mondragón-Flores ◽  
Juan Pedro Luna-Arias ◽  
Cinthia Teresa Enríquez-Nieto ◽  
Berenice Parra-Ortega ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Morphological Changes ◽  
Optimal Conditions ◽  
Aeromonas Caviae

scholarly journals Effects of Different Environmental Factors on the Growth and Bioactive Substance Accumulation of Porphyridium purpureum

2020 ◽  
Vol 17 (7) ◽  
pp. 2221
Author(s):  
Xudan Lu ◽  
Fangru Nan ◽  
Jia Feng ◽  
Junping Lv ◽  
Qi Liu ◽  
...  
Keyword(s):  
Growth Process ◽  
Production Efficiency ◽  
Culture Conditions ◽  
Extracellular Polysaccharides ◽  
Optimal Conditions ◽  
Bioactive Substances ◽  
Porphyridium Purpureum ◽  
Optimal Production ◽  
Bioactive Substance ◽  
Product Accumulation

Genus Porphyridium is a primitive single-celled red algae widely distributed in seawater, freshwater, and moist soil. It can synthesize bioactive substances such as phycoerythrin, extracellular polysaccharides and polyunsaturated fatty acids during the growth process. In this paper, the culture and bioactive substance yield of Porphyridium purpureum were studied by setting salinity, nitrogen-to-phosphorus ratio, and pH at different gradient levels. The results showed that the optimal conditions for the growth of P. purpureum were salinity 34 ppt, nitrogen-to-phosphorus ratio 169:1, and pH 8; the optimal conditions for obtaining the polysaccharides were salinity 17 ppt, nitrogen-to-phosphorus ratio 14:1, and pH 8; the optimal conditions for obtaining phycoerythrin were salinity 17 ppt, nitrogen-to-phosphorus ratio 68:1, and pH 8; the optimal conditions for obtaining the lipids were salinity 34 ppt, nitrogen-to-phosphorus ratio 1:1, and pH 8. In actual production applications, culture conditions should be set according to different product accumulation purposes in order to achieve the optimal production efficiency.

scholarly journals Sliding Motility, Biofilm Formation, and Glycopeptidolipid Production inMycobacterium colombienseStrains

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Milena Maya-Hoyos ◽  
John Leguizamón ◽  
Leonardo Mariño-Ramírez ◽  
Carlos Y. Soto
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Gene Cluster ◽  
Mycobacterium Avium ◽  
Biofilm Formation ◽  
Culture Conditions ◽  
Bioinformatics Analyses ◽  
Chromatographic Behaviour ◽  
Immunosuppressed Patients ◽  
Layer Chromatography

Mycobacterium colombienseis a novel member of theMycobacterium aviumcomplex, which produces respiratory and disseminated infections in immunosuppressed patients. Currently, the morphological and genetic bases underlying the phenotypic features ofM. colombiensestrains remain unknown. In the present study, we demonstrated thatM. colombiensestrains displaying smooth morphology show increased biofilm formation on hydrophobic surfaces and sliding on motility plates. Thin-layer chromatography experiments showed thatM. colombiensestrains displaying smooth colonies produce large amounts of glycolipids with a chromatographic behaviour similar to that of the glycopeptidolipids (GPLs) ofM. avium. Conversely, we observed a natural rough variant ofM. colombiense(57B strain) lacking pigmentation and exhibiting impaired sliding, biofilm formation, and GPL production. Bioinformatics analyses revealed a gene cluster that is likely involved in GPL biosynthesis inM. colombienseCECT 3035. RT-qPCR experiments showed that motile culture conditions activate the transcription of genes possibly involved in key enzymatic activities of GPL biosynthesis.

scholarly journals Contributions of Francisella tularensis subsp. novicida Chitinases and Sec Secretion System to Biofilm Formation on Chitin

2009 ◽  
Vol 76 (2) ◽  
pp. 596-608 ◽  
Author(s):  
Jeffrey J. Margolis ◽  
Sahar El-Etr ◽  
Lydia-Marie Joubert ◽  
Emily Moore ◽  
Richard Robison ◽  
...  
Keyword(s):  
Carbon Source ◽  
Francisella Tularensis ◽  
Biofilm Formation ◽  
Secreted Proteins ◽  
Tularensis Subsp ◽  
Transmission Mechanisms ◽  
One Step ◽  
Sec Translocon ◽  
Mammalian Infection ◽  
Exogenous Sugar

ABSTRACT Francisella tularensis, the zoonotic cause of tularemia, can infect numerous mammals and other eukaryotes. Although studying F. tularensis pathogenesis is essential to comprehending disease, mammalian infection is just one step in the ecology of Francisella species. F. tularensis has been isolated from aquatic environments and arthropod vectors, environments in which chitin could serve as a potential carbon source and as a surface for attachment and growth. We show that F. tularensis subsp. novicida forms biofilms during the colonization of chitin surfaces. The ability of F. tularensis to persist using chitin as a sole carbon source is dependent on chitinases, since mutants lacking chiA or chiB are attenuated for chitin colonization and biofilm formation in the absence of exogenous sugar. A genetic screen for biofilm mutants identified the Sec translocon export pathway and 14 secreted proteins. We show that these genes are important for initial attachment during biofilm formation. We generated defined deletion mutants by targeting two chaperone genes (secB1 and secB2) involved in Sec-dependent secretion and four genes that encode putative secreted proteins. All of the mutants were deficient in attachment to polystyrene and chitin surfaces and for biofilm formation compared to wild-type F. novicida. In contrast, mutations in the Sec translocon and secreted factors did not affect virulence. Our data suggest that biofilm formation by F. tularensis promotes persistence on chitin surfaces. Further study of the interaction of F. tularensis with the chitin microenvironment may provide insight into the environmental survival and transmission mechanisms of this pathogen.

Study on Screening of Glutathione over-Production Strain and its Fermentation Conditions

2011 ◽  
Vol 396-398 ◽  
pp. 1657-1661
Author(s):  
Jie Gang ◽  
Li Feng Shan ◽  
Hong Yu Bu
Keyword(s):  
Shake Flask ◽  
Fermentation Medium ◽  
Culture Conditions ◽  
Shake Flask Culture ◽  
Optimal Conditions ◽  
Flask Culture ◽  
Fermentation Conditions ◽  
Physiological And Biochemical Characteristics ◽  
Physiological And Biochemical ◽  
Production Strain

This study was to screen strains for glutathione over-production. A high GSH-producing strain HSJB1 was isolated from soil.According to the morphological, physiological and biochemical characteristics of cells, this strain was primarily identified as Saccharomyces cerevisiae. The glutathion fermentation conditions of this strain by shake flask culture were studied.The optimal fermentation medium was as follows: glucose 20g/L, (NH4)2SO4 5g/L, peptone 12.5 g/L, KH2PO4 9.0 g/L, MgSO4•7H2O 1.0 g/L, NaCl 0.2 g/L, ZnSO4•H2O 0.01 g/L. The optimal culture conditions were as follows :pH 5，broth quantity 30ml/250ml, temperature 28°C，inoculum 10%. Under the optimal conditions, the glutathione productivity and biomass were 53.60 mg/L and 3.8 g/L, respectively, which were 11.2% and 11.8% higher than those in the original conditions, respectively.

scholarly journals Detection of luxS gene expression under stressing factors for biofilm formation by Propionibacterium acidipropionici and Propionibacterium freudenreichii

2015 ◽  
Vol 5 (2) ◽  
pp. 604-613 ◽  
Author(s):  
Danitza Xiomara Romero ◽  
Oscar Víctor Cárdenas Alegría ◽  
Víctor Hugo Cavero Olguin ◽  
María Teresa Álvarez Aliaga
Keyword(s):  
Gene Expression ◽  
Biofilm Formation ◽  
Fluorescent In Situ Hybridization ◽  
Culture Conditions ◽  
Propionibacterium Freudenreichii ◽  
Pathogenic Microorganisms ◽  
Luxs Gene ◽  
Propionibacterium Acidipropionici ◽  
Biofilm Reactors

Gene expression constitutes an important role in cellular communication, setting mechanisms for biofilm formation. Genes can be used as molecular markers to monitor viability, stability and maintenance of biofilm eg. in biofilm reactors, bioremediation and biotransformation frequently under stressing conditions to enhance or limit the biofilm formation. In the present study, no pathogenic microorganisms of industrial interest were used. Propionibacterium freudenreichiisubsp. shermanii DSM 4902T and P. acidipropionici DSM 4900Tstrains cannot produce biofilm in culture conditions previously reported. In this regard, chemical culture conditions were modified to stimulate biofilm formation in both strains and determine that under stressing conditions such as 0.6 M NaCl, 1.8 M glucose and 10 gL-1 yeast extract both Propionibacterium produce biofilm. Finally, luxS expression was identified in biofilm of both strains by modified fluorescent in situ hybridization expression (FISH expression).

scholarly journals Reproductive performance of asian catfish (Hemibagrus wyckii Bagridae), a candidate species for aquaculture

F1000Research ◽  
2018 ◽  
Vol 7 ◽  
pp. 683 ◽  
Author(s):  
Netti Aryani ◽  
Indra Suharman ◽  
Hafrijal Syandri
Keyword(s):  
Reproductive Performance ◽  
Fertilization Rate ◽  
Culture Conditions ◽  
Hatching Rate ◽  
Male Fish ◽  
Egg Weight ◽  
Study Results ◽  
Candidate Species ◽  
Asian Catfish ◽  
Egg Diameter

Background: Hemibagrus wyckii Bagridae is one of the most important economic fish species that lives in the rivers and reservoir in Riau Province, Indonesia. The present study aimed to determine the reproductive performance of H.wyckii under culture conditions. Methods: A total of 10 female and 10 male fish were selected, and weight, length, characteristics of egg and sperm, and hatchery performance were measured. Eggs were fertilized using the dry method. Egg weight and egg diameters were measured for 50 eggs per female. Egg size (50 eggs for each fish) was measured using an Olympus microscope (CX40). Then, saline solution was added over the eggs, followed by the addition of pooled sperm from 10 males. Results: Average relative fecundity, egg weight and egg diameter were 2060±512 eggs/kg fish, 29.86±1.21 mg and 2.67±0.26 mm, respectively. The fertilization rate and hatching rate were 60.91±4.68% and 42.91±2.92% respectively. Sperm characteristics such as volume per fish (mL), pH, concentration (per mL), motility (%) and duration of motility (second) were 0.82±0.20, 7.15±0.12, 3.68±0.15, 72.77±1.46 and 47.5±4.84, respectively. Conclusion: The study results and scientific observations regarding reproductive performance suggest that H. wyckii can be considered a new candidate species for aquaculture.

scholarly journals Advanced understanding of prokaryotic biofilm formation using a cost-effective and versatile multi-panel adhesion (mPAD) mount

2022 ◽  
Author(s):  
Stefan Schulze ◽  
Heather Schiller ◽  
Jordan Solomonic ◽  
Orkan Telhan ◽  
Kyle Costa ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Cost Effective ◽  
Flow Chamber ◽  
Culture Conditions ◽  
Multiple Time ◽  
Wild Type ◽  
Surface Attachment ◽  
Flowing Liquid ◽  
Multiple Time Points ◽  
Static Conditions

Most microorganisms exist in biofilms, which comprise aggregates of cells surrounded by an extracellular matrix that provides protection from external stresses. Based on the conditions under which they form, biofilm structures vary in significant ways. For instance, biofilms that develop when microbes are incubated under static conditions differ from those formed when microbes encounter the shear forces of a flowing liquid. Moreover, biofilms develop dynamically over time. Here, we describe a cost-effective, 3D-printed coverslip holder that facilitates surface adhesion assays under a broad range of standing and shaking culture conditions. This multi-panel adhesion (mPAD) mount further allows cultures to be sampled at multiple time points, ensuring consistency and comparability between samples and enabling analyses of the dynamics of biofilm formation. As a proof of principle, using the mPAD mount for shaking, oxic cultures, we confirm previous flow chamber experiments showing that Pseudomonas aeruginosa wild type and a phenazine deletion mutant (Δ phz ) form biofilms with similar structure but reduced density in the mutant strain. Extending this analysis to anoxic conditions, we reveal that microcolony and biofilm formation can only be observed under shaking conditions and are decreased in the Δ phz mutant compared to wild-type cultures, indicating that phenazines are crucial for the formation of biofilms if oxygen as an electron acceptor is unavailable. Furthermore, while the model archaeon Haloferax volcanii does not require archaella for surface attachment under static conditions, we demonstrate that H. volcanii mutants that lack archaella are impaired in early stages of biofilm formation under shaking conditions. Importance: Due to the versatility of the mPAD mount, we anticipate that it will aid the analysis of biofilm formation in a broad range of bacteria and archaea. Thereby, it contributes to answering critical biological questions about the regulatory and structural components of biofilm formation and understanding this process in a wide array of environmental, biotechnological, and medical contexts.

scholarly journals Uncovering ED: A Qualitative Analysis of Personal Blogs Managed by Individuals with Eating Disorders

2014 ◽  
Author(s):  
Jacqueline Gies ◽  
Sara Martino
Keyword(s):  
Eating Disorders ◽  
Grounded Theory ◽  
Eating Disorder ◽  
Qualitative Analysis ◽  
Future Research ◽  
Study Results ◽  
Mind And Body ◽  
Self Worth ◽  
Harmful Effects

Previous studies have investigated the potential harmful effects of pro-eating disorder (ED) websites. Websites, such as personal blogs, may contain eating disorder content that may hold important information as well and must be considered. Fifteen blogs hosted by the site “Tumblr” were qualitatively analyzed. Each blog owner was anonymous and all were female. Ten main themes were extracted using grounded theory: interaction, negative self-worth, mind and body disturbances, pictures, eating disorders, suicide, diet, exercise, stats, and recovery. Additional themes also appeared in the study. Results indicate that although each individual blog is unique to its owner, common concepts existed among the majority. The implications for the information in the ED blogs and directions for future research are discussed.

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