scholarly journals BIOFILM – ORGANISATION OF BACTERIA LIFE IN NATURAL ECO SYSTEMS

2008 ◽  
Vol 1 (2) ◽  
pp. 5-15 ◽  
Author(s):  
Dubravka Milanov ◽  
Ružica Ašanin ◽  
Branka Vidić ◽  
Dejan Krnjajić ◽  
Jelena Petrović
Keyword(s):  
Gene Transcription ◽  
Intercellular Communication ◽  
Biofilm Formation ◽  
Transcription Profile ◽  
Natural Ecosystems ◽  
Microbial Biofilms ◽  
Unicellular Organisms ◽  
Gene Transcription Profile ◽  
Different Characteristics ◽  
Chronic Course

In all natural ecosystems, including both humans and animals, bacteria show a tendency to bind on the surface and form a structure known as biofilm. Biofilm formation is a genetically regulated process in the life of bacteria and has several phases demanding intercellular communication. In biofilms bacteria express different characteristics comparing to their free suspended counterparts, due to different gene transcription profile and increased resistance towards antibiotics and disinfectants. Discovery of microbial biofilms has changed our understanding of bacteria, that are not viewed only as unicellular organisms, but more as a multi-cellular community that in some characteristics imitates primitive eukaryotic tissue. In the last decades there is an increasing evidence on infections caused by bacteria that form biofilms, and have a chronic course with possibility of recidives. Conventional methods of killing microbes by antibiotics and biocides is usually ineffective in bacteria organized in biofilms.

scholarly journals Phenotypic transitions enacted by simulated microgravity do not alter coherence in gene transcription profile

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Agnese Po ◽  
Alessandro Giuliani ◽  
Maria Grazia Masiello ◽  
Alessandra Cucina ◽  
Angela Catizone ◽  
...  
Keyword(s):  
Gene Expression ◽  
Gene Transcription ◽  
Simulated Microgravity ◽  
Correlation Coefficients ◽  
Transcription Profile ◽  
Random Positioning Machine ◽  
Functional Changes ◽  
Internal Gene ◽  
Gene Transcription Profile ◽  
Space Cell

AbstractCells in simulated microgravity undergo a reversible morphology switch, causing the appearance of two distinct phenotypes. Despite the dramatic splitting into an adherent-fusiform and a floating-spherical population, when looking at the gene-expression phase space, cell transition ends up in a largely invariant gene transcription profile characterized by only mild modifications in the respective Pearson’s correlation coefficients. Functional changes among the different phenotypes emerging in simulated microgravity using random positioning machine are adaptive modifications—as cells promptly recover their native phenotype when placed again into normal gravity—and do not alter the internal gene coherence. However, biophysical constraints are required to drive phenotypic commitment in an appropriate way, compatible with physiological requirements, given that absence of gravity foster cells to oscillate between different attractor states, thus preventing them to acquire a exclusive phenotype. This is a proof-of-concept of the adaptive properties of gene-expression networks supporting very different phenotypes by coordinated ‘profile preserving’ modifications.

scholarly journals Effects on Gene Transcription Profile and Fatty Acid Composition by Genetic Modification of Mevalonate Diphosphate Decarboxylase MVD/Erg19 in Aspergillus Oryzae

2019 ◽  
Vol 7 (9) ◽  
pp. 342
Author(s):  
Hu ◽  
Huang ◽  
Sun ◽  
Niu ◽  
Xu ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Gene Transcription ◽  
Aspergillus Oryzae ◽  
Acid Content ◽  
Ergosterol Biosynthesis ◽  
Transcription Profile ◽  
Control Strain ◽  
Overexpression Strain ◽  
Mevalonate Diphosphate Decarboxylase ◽  
Gene Transcription Profile

Mevalonate diphosphate decarboxylase MVD/Erg19 is required for ergosterol biosynthesis, growth, sporulation, and stress tolerance in Aspergillus oryzae. In this study, RNA-seq was used to analyze the gene transcription profile in AoErg19 overexpression (OE) and RNAi strains. There were 256 and 74 differentially expressed genes (DEGs) in AoErg19 OE and RNAi strains, respectively, compared with the control strain (CK). The most common DEGs were transport- and metabolism-related genes. Only 22 DEGs were obtained that were regulated in both OE and RNAi strains. The transcriptomic comparison between CK and AoErg19 overexpression strain (CK vs. OE), and between CK and AoErg19 RNAi strain (CK vs. RNAi) revealed that the greatest difference existed in the number of genes belonging to the cytochrome P450 family; 12 were found in CK vs. OE, whereas 1 was found in CK vs. RNAi. The expression patterns of lipid biosynthesis and metabolism related genes were altered in OE and RNAi strains, either by gene induction or suppression. Moreover, the total fatty acid content in the RNAi strain was 12.1% greater than the control strain, but no difference in total acid content was found between the overexpression strain and the control strain. Therefore, this study highlights the gene expression regulation within mevalonate (MVA), ergosterol biosynthesis, and fatty acid biosynthesis pathways.

scholarly journals Silver-Derived Antimicrobial Coatings for the Prevention of Microbial Biofilms in Metal Pipes

2021 ◽  
Vol 232 (8) ◽  
Author(s):  
M. Vela-Cano ◽  
C. Garcia-Fontana ◽  
F. Osorio ◽  
A. González-Martinez ◽  
J. González-López
Keyword(s):  
Biofilm Formation ◽  
Antimicrobial Properties ◽  
Pilot Scale ◽  
Biological Factors ◽  
Antimicrobial Coatings ◽  
Microbial Biofilms ◽  
Physical Chemical ◽  
Silver Zeolite ◽  
Metal Pipes ◽  
Pipeline Corrosion

AbstractBiodeterioration is one of the most important processes in metal pipeline corrosion, and it can be due to physical, chemical, and biological factors. Coatings rich in silver have been used to inhibit this undesirable phenomenon. In this study, the antimicrobial properties of several silver-containing products used as a coating in pipelines were determined on a pilot scale in order to evaluate the ability of silver to inhibit biofilm formation. The results showed that the coating with silver zeolite at a concentration of 2000 mg L–1 inhibited the formation of a microbial biofilm and prevented the biodeterioration process. Therefore, from our study, it can be concluded that silver zeolite shows greater protection capacity than other silver preparations and presents advantages in relation to other silver coatings that are currently available

scholarly journals Using micro-patterned surfaces to inhibit settlement and biofilm formation by Bacillus subtilis

2017 ◽  
Vol 63 (7) ◽  
pp. 608-620 ◽  
Author(s):  
Siyuan Chang ◽  
Xiaodong Chen ◽  
Shuo Jiang ◽  
Jinchun Chen ◽  
Lin Shi
Keyword(s):  
Bacillus Subtilis ◽  
Biofilm Formation ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Patterned Surfaces ◽  
Heat Transfer Efficiency ◽  
Treated Sewage ◽  
Different Characteristics ◽  
Precision Balance

Biofilm is a biological complex caused by bacteria attachment to the substrates and their subsequent reproduction and secretion. This phenomenon reduces heat transfer efficiency and causes significant losses in treated sewage heat-recovering systems. This paper describes a physical approach to inhibit bacteria settlement and biofilm formation by Bacillus subtilis, which is the dominant species in treated sewage. Here, micro-patterned surfaces with different characteristics (stripe and cube) and dimensions (1–100 μm) were fabricated as surfaces of interest. Model sewage was prepared and a rotating coupon device was used to form the biofilms. Precision balance, scanning electron microscopy, and confocal laser scanning microscopy (CLSM) were employed to investigate the inhibitory effects and the mechanisms of the biofilm–surface interactions. The results have shown that surfaces with small pattern sizes (1 and 2 μm) all reduced biofilm formation significantly. Interestingly, the CLSM images showed that the surfaces do not play a role in “killing” the bacteria. These findings are useful for future development of new process surfaces on which bacteria settlement and biofilm formation can be inhibited or minimized.

scholarly journals Biofilm Formation Caused by Clinical Acinetobacter baumannii Isolates Is Associated with Overexpression of the AdeFGH Efflux Pump

2015 ◽  
Vol 59 (8) ◽  
pp. 4817-4825 ◽  
Author(s):  
Xinlong He ◽  
Feng Lu ◽  
Fenglai Yuan ◽  
Donglin Jiang ◽  
Peng Zhao ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Gene Transcription ◽  
Biofilm Formation ◽  
Efflux Pump ◽  
Outer Membrane Proteins ◽  
Content Type ◽  
Potential Association ◽  
Genes Encoding ◽  
Clinical Environments

ABSTRACTChronic wound infections are associated with biofilm formation, which in turn has been correlated with drug resistance. However, the mechanism by which bacteria form biofilms in clinical environments is not clearly understood. This study was designed to investigate the biofilm formation potency ofAcinetobacter baumanniiand the potential association of biofilm formation with genes encoding efflux pumps, quorum-sensing regulators, and outer membrane proteins. A total of 48 clinically isolatedA. baumanniistrains, identified by enterobacterial repetitive intergenic consensus (ERIC)-PCR as types A-II, A-III, and A-IV, were analyzed. Three representative strains, which were designatedA. baumanniiABR2, ABR11, and ABS17, were used to evaluate antimicrobial susceptibility, biofilm inducibility, and gene transcription (abaI,adeB,adeG,adeJ,carO, andompA). A significant increase in the MICs of different classes of antibiotics was observed in the biofilm cells. The formation of a biofilm was significantly induced in all the representative strains exposed to levofloxacin. The levels of gene transcription varied between bacterial genotypes, antibiotics, and antibiotic concentrations. The upregulation ofadeGcorrelated with biofilm induction. The consistent upregulation ofadeGandabaIwas detected in A-III-typeA. baumanniiin response to levofloxacin and meropenem (1/8 to 1/2× the MIC), conditions which resulted in the greatest extent of biofilm induction. This study demonstrates a potential role of the AdeFGH efflux pump in the synthesis and transport of autoinducer molecules during biofilm formation, suggesting a link between low-dose antimicrobial therapy and a high risk of biofilm infections caused byA. baumannii. This study provides useful information for the development of antibiofilm strategies.

scholarly journals The Effect of Gold and Iron-Oxide Nanoparticles on Biofilm-Forming Pathogens

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Madhu Bala Sathyanarayanan ◽  
Reneta Balachandranath ◽  
Yuvasri Genji Srinivasulu ◽  
Sathish Kumar Kannaiyan ◽  
Guruprakash Subbiahdoss
Keyword(s):  
Iron Oxide ◽  
Iron Oxide Nanoparticles ◽  
Immune Cells ◽  
Biofilm Formation ◽  
Bacterial Infections ◽  
Medical Applications ◽  
Oxide Nanoparticles ◽  
Biofilm Growth ◽  
Microbial Biofilms ◽  
Exopolymeric Substances

Microbial biofilms on biomaterial implants or devices are hard to eliminate by antibiotics due to their protection by exopolymeric substances that embed the organisms in a matrix, impenetrable for most antibiotics and immune-cells. Application of metals in their nanoparticulated form is currently considered to resolve bacterial infections. Gold and iron-oxide nanoparticles are widely used in different medical applications, but their utilisation to eradicate biofilms on biomaterials implants is novel. Here, we studied the effect of gold and iron oxide nanoparticles on Staphylococcus aureus and Pseudomonas aeruginosa biofilms. We report that biofilm growth was reduced at higher concentrations of gold and iron-oxide nanoparticles compared to absence of nanoparticles. Thus nanoparticles with appropriate concentration could show significant reduction in biofilm formation.

Visualization of microbial biofilms in case of digestive disorders in lambs

2021 ◽  
Vol 1 (1) ◽  
pp. 59-67
Author(s):  
E. M. Lenchenko ◽  
N. P. Sachivkina ◽  
D. A. Blumenkrants ◽  
A. Yu. Arsenyuk
Keyword(s):  
Biofilm Formation ◽  
Three Dimensional ◽  
Density Measurement ◽  
Yeast Cells ◽  
Active Growth ◽  
Microbial Structures ◽  
Microbial Biofilms ◽  
Dense Grid ◽  
Digestive Disorders ◽  
Biofilm Structure

The paper demonstrates morphometric and densitometric parameters of microbial biofilms recovered from lambs with digestive disorders. Changes of quantitative and species composition of the intestinal microbiocenoses in the lambs with digestive disorders were compared with the ones of the clinically healthy lambs. Light microscopy results demonstrated formation of three-dimensional biofilm structure in the form of dense grid consisting of gram-negative and gram-positive bacteria, yeast cells, hyphas and pseudohyphas surrounded with intracellular polymer matrix. Presence of blastospores aided to the increased number of cells attached to the substrate, and biofilm was formed, which consisted of rod and round cells attached to the microfungi cells. In the process of dispersion that occurred during the destruction of the intercellular matrix and bacterial and yeast cell detachment, branched structures separated from the microcolonies and colonized microorganism- free regions of the substrate. The intensity of biofilm formation by the microorganisms under study was evaluated by optic density measurement in 48 hours of cultivation. Fluorescence microscopy results demonstrated that the dynamics of changes of the viable microbial structures was specified by intermittent periods of increased or decreased biofilm formation intensity. Cells characterized by active growth and replication and forming alternating subpopulations were detected in the examined microbial cultures. When determining the viability of the microorganisms in the biofilms, the viable (green fluorescence) and non-viable (red fluorescence) cells were differentiated.

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