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Genes and genomics
Published in Firdos Alam Khan, Biotechnology Fundamentals, 2018
One of the distinct features of a prokaryote is the absence of nucleus in the cytoplasm and DNA is usually condensed in a nucleoid. Prokaryotes can carry extrachromosomal DNA elements called plasmids, which are usually circular. Plasmids enable additional functions, such as antibiotic resistance. The presence of plasmid DNA in bacteria not only makes bacteria distinct from animals and plants but also makes it an important genetic engineering tool (Figure 2.1).
Detection of multidrug-resistant Pseudomonas isolates and distribution of denitrifying functional genes
Published in International Journal of Environmental Health Research, 2021
Nur Önal, Cumhur Avşar, E. Sümer Aras
The extrachromosomal DNA of the strains was isolated according to the method of Sambrook et al. (1989). Extraction of whole-cell proteins was carried out according to the method of Laemmli (1970). Protein analysis was carried out with Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis (SDS-PAGE) in gel slabs of 1 mm thickness (4% stacking and 10% resolving gels for total proteins) as described by Laemmli (1970). Electrophoresis was performed with a discontinuous buffer system in a vertical electrophoresis (Hoefer SE400, USA) at 20 mA for stacking gel and at 30 mA for resolving gel. Following electrophoresis, gels were stained overnight with Coomassie Brilliant Blue R-250 and destained in a mixture of methanol-acetic acid-water (3:1:6) until clearly visible protein bands obtained. Protein molecular masses were calculated with the comparison of a marker (PageRulerTM Unstained Protein Ladder, Fermantas, SM0661) (Berber et al. 2017).
Microbiology in Water-Miscible Metalworking Fluids
Published in Tribology Transactions, 2020
Frederick J. Passman, Peter Küenzi
This complex biofilm architecture creates a number of chemical gradients. In particular, oxygen and organic nutrient concentrations and pH gradients develop, allowing co-habitation of anaerobic and aerobic, acidophilic, and acidophobic microorganisms. All of these cells “talk” to each other to coordinate adhesion, biofilm maturation, exploitation of extracellular public goods, and swarming in a process known as quorum sensing (QS) (66–68). This communication among biofilm cells involves the production and detection of signaling molecules and the horizontal transfer of genetic material (cell-to-cell transfer of extrachromosomal DNA). Additionally, heterogenic biofilms consisting of multiple species may support each other in gaining the necessary organic molecules for growth and survival (69) in a way that comes close to symbiosis.