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Biomedical subjects

F Milanovich

Publications and source records attributed to F Milanovich.

4 recordsLinked to original sources
PubMed1999

A minisonicator to rapidly disrupt bacterial spores for DNA analysis.

Concerns about the use of anthrax spores as a weapon of mass destruction have motivated the development of portable instruments capable of detecting and monitoring a suspected release of the agent. Optimal detection of bacterial spores by PCR requires that the spores be disrupted to make the endogenous DNA available for amplification. The entire process of spore lysis, PCR, and detection can take several hours using conventional methods and instruments. In this report, a minisonicator and prototype spore lysis cartridge were built to disrupt Bacillus spores in 30 s for rapid, real-time PCR analysis. Utilization of the minisonicator improved PCR analysis by decreasing the limit of detection, reducing the time of detection, and increasing the signal amplitude. Total time of spore disruption and detection using the minisonicator and a microchip PCR instrument was less than 15 min.

Bacillus anthracis↗
PubMed1998

Rapid pathogen detection using a microchip PCR array instrument.

An array of PCR microchips for rapid, parallel testing of samples for pathogenic microbes is described. The instrument, called the Advanced Nucleic Acid Analyzer (ANAA), utilizes 10 silicon reaction chambers with thin-film resistive heaters and solid-state optics. Features of the system include efficient heating and real-time monitoring, low power requirements for battery operation, and no moving parts for reliability and ruggedness. We analyzed cultures of Erwinia herbicola vegetative cells, Bacillus subtilis spores, and MS2 virions, which simulated pathogenic microbes such as Yersinia pestis, Bacillus anthracis spores, and Venezuelan equine encephalitis, respectively. Detection of microbes was achieved in as little as 16 min with detection limits of 10(5)-10(7) organisms/L (10(2)-10(4) organisms/mL).

Bacillus subtilis↗
PubMed1981

Escherichia coli ribosome unfolding in low Mg2+ solutions observed by laser Raman spectroscopy and electron microscopy.

Ribosomes unfolded by the removal of Mg2+ at 25 degrees C were studied by Raman spectroscopy and electron microscopy. Raman spectra showed a reduction in the 813 cm-1 phosphodiester signal of 30S and 50S ribosomes compared to intact ribosomes, suggesting that a fraction of the ribose moieties had shifted from the 3' endo (ordered) to the 3' exo (disordered) conformation. The maximum diameters of unfolded 30S and 50S ribosomes, judged by electron microscopy, were 1.8 and 2.5-fold greater, respectively, than those of intact ribosomes. Most unfolded 30S ribosomes had three distinct structural domains and appeared "Y-shaped"; whereas most unfolded 50S ribosomes had four distinct domains and appeared "X-shaped". When ribosomes were partially unfolded (by brief exposure to 0.04 mM Mg2+ or EDTA), several possible intermediates in the unfolding process were observed. Both the shapes of particles and their Raman spectra reached the same final state in 0.04 mM Mg2+, where more than 50% of the rRNA phosphates are discharged by Mg2+, as in 10 mM EDTA, where less than 1% are discharged.

Escherichia coli↗