Co-culture of Streptomyces with mycolic acid-containing bacteria (MACB), which we termed "combined-culture," alters the secondary metabolism pattern in Streptomyces and has been a useful method for the discovery of bioactive natural products. In the course of our investigation to identify the inducing factor(s) of MACB, we previously observed that production of pigments in Streptomyces lividans...

Dilute solutions of dyes were applied to animal or plant cells nearly as far back as a century ago. By this means it was sought to gain an insight into various life processes of the cells, to demonstrate certain cellular structures, or to find out whether the cell were dead or alive. The work started by Ehrlich on nerve cells and blood cells, and the stimulus it gave other workers, have given u...

Quantitative studies of dye adsorption by bacteria have been made (Kennedy and Barbaro, 1953; Barbaro and Kennedy, 1954; Kennedy and Woodhour, 1956; Barbaro et al., 1956) in order to measure the degree of gram-positiveness, and to study the influence of several factors on the quantity of dye retained by the microorganisms. No attention has been given, however, to the applicability of the physic...

Contactless dielectrophoresis (cDEP) is a recently developed method of cell manipulation in which the electrodes are physically isolated from the sample. Here we present two microfluidic devices capable of selectively isolating live human leukemia cells from dead cells utilizing their electrical signatures. The effect of different voltages and frequencies on the gradient of the electric field a...

Until now, the question as to the role of immunological mechanisms in neuronal death of extrapyramidal cell systems in Parkinson's disease (PD) has not been fully resolved. One of the approaches includes examination of circulating blood cells. In our studies on 24 PD patients, peripheral blood was studied before and after medication with L-DOPA compounds. Patients with PD demonstrated an increa...

We have developed a new method for accurate quantification of dead microbial cells. This technique employs the simultaneous use of fluorescent hydrazides and nucleic acid dyes. Fluorescent hydrazides allow detection of cells that cannot be detected with currently used high-affinity nucleic acid dyes. This is particularly important for nongrowing bacterial populations and for multicellular commu...

The metabolic activity of living organisms results in cellular motion on a nanometric scale that can be efficiently detected by micro- and nano- fabricated sensors. Quartz crystal microbalance atomic force microscopy (AFM) inspired techniques have recently demonstrated their ability to successfully measure the microorganisms. Monitoring these fluctuations while exposing microorganisms various c...

In recent years, use of the DNA-intercalating dye propidium monoazide (PMA) in real-time PCR has been reported as a novel method to detect viable bacteria in different types of samples, such as food, environmental, and microbiological samples. In this study, viable cells of Acidovorax citrulli, the causal agent of bacterial seedling blight and fruit blotch, were selectively detected and differe...

By redesigning the established methylene blue reduction test for bacteria and yeast, we present a cheap and efficient methodology for quantitative physiology of eukaryotic cells applicable for high-throughput systems. Validation of the method in fermenters and high-throughput systems proved equivalent, displaying reduction curves that interrelated directly with CFU counts. For growth rate estim...