Using two different types of impedance biochips (PS5 and BS5) with ring top electrodes, a distinct change of measured impedance has been detected after adding 1-5 µL (with dead or live Gram-positive JG-A12 cells to 20 µL DI water inside the ring top electrode. We relate observed change of measured impedance to change of membrane potential of JG-A12 cells. In contrast to impedance measurements, optical density (OD) measurements cannot be used to distinguish between dead and live cells. Dead JG-A12 cells have been obtained by adding 0.02 mg/mL of the antibiotics tetracycline and 0.1 mg/mL chloramphenicol to a batch with OD0.5 and by incubation for 24 h, 30 °C, 120 rpm in the dark. For impedance measurements, we have used batches with a cell density of 25.5 × 10 cells/mL (OD8.5) and 270.0 × 10 cells/mL (OD90.0). The impedance biochip PS5 can be used to detect the more resistive and less capacitive live JG-A12 cells. Also, the impedance biochip BS5 can be used to detect the less resistive and more capacitive dead JG-A12 cells. An outlook on the application of the impedance biochips for high-throughput drug screening, e.g., against multi-drug-resistant Gram-positive bacteria, is given.
Using two different types of impedance biochips (PS5 and BS5) with ring top electrodes, a distinct change of measured impedance has been detected after adding 1-5 µL (with dead or live Gram-positive JG-A12 cells to 20 µL DI water inside the ring top electrode. We relate observed change of measured impedance to change of membrane potential of JG-A12 cells. In contrast to impedance measurements, optical density (OD) measurements cannot be used to distinguish between dead and live cells.
A cDNA fragment encoding the S-layer protein SllB cloned from Bacillus sphaericus ATCC 14577 was expressed on the surface of E. coli BL21 (DE3) cells and confirmed by the square lattice structure at the nanoscale level. The amplified gene fragment designed with PCR primers from a specified reference sequence (GenBank accession no.
Escherichia coli is one of the best studied micro-organisms and is the most widely used host in genetic engineering. The Gram-negative single cells are rod-shaped, and filaments are usually not found. Here, we describe the reproducible formation of elongated E.
Aims: To fabricate and analyse Pd nanoparticles on immobilized bacterial cells.
Methods And Results: Biological ceramic composites (biocers) were used as a template to produce Pd(0) nanoparticles. The metal-binding cells of the uranium mining waste pile isolate, Bacillus sphaericus JG-A12 were used as a biological component of the biocers and immobilized by using sol-gel technology.
