The phylogenetic relationships among 36 validly described species or subspecies within the genus Staphylococcus were investigated by cloning and sequencing their 60 kDa heat-shock protein (HSP6O) genes using a set of universal degenerate HSP6O PCR primers. The cloned partial HSP60 DNA sequences f rom nine Staphylococcus aureus strains were highly conserved (97-100% DNA sequence similarity; mean 98O/0), indicating that the HSP60 gene of multiple isolates within the same species have little microheterogeneity. A t the subspecies level, DNA sequence similarity among members of 5. aureus, Staphylococcus schleiferi, Staphylococcus cohnii and Staphylococcus capitis ranged from 91 to 98%. A t the interspecies level, sequence similarity among 23 distinct species of staphylococci ranged from 74 to 93 O/ O (mean 82 YO). By comparison, the highest sequence similarity of Bacillus subtilis and Escherichia coli with members within the genus Staphylococcus was only 70 and 59 %, respectively. Importantly, phylogenetic analysis based on the neighbour-joining distance method revealed remarkable concordance between the tree derived from partial HSP60 gene sequences and that based on genomic DNA-DNA hybridization, while 165 rRNA gene sequences correlated less well. The results demonstrate that DNA sequences from the highly conserved and ubiquitous HSP6O gene offer a convenient and accurate tool for species-specif ic identification and phylogenetic analysis of staphylococci.

We present 50 cm long microchannels in a monolithic device for high resolution, long read‐length DNA sequencing. These devices were fabricated and bonded in borofloat glass using unconventional photolithography techniques with 48—188 independent, straight microchannels. The microchannel DNA separation was tested with POP‐6™ polymer and a DNA sequencing ladder separated at room temperature and 200 V/cm. Single‐base resolution greater than 600 bases was achieved and the sequence base called to 640 bases with 98% accuracy. Under the same experimental conditions, the performance of the microchip was identical to a fused‐silica capillary with similar cross‐sectional area.

A capillary array electrophoresis DNA sequencer is reported based on a micromachined sheath-flow cuvette as the detection chamber. This cuvette is equipped with a set of micromachined features that hold the capillaries in precise registration to ensure uniform spacing between the capillaries, in order to generate uniform hydrodynamic flow in the cuvette. A laser beam excites all of the samples simultaneously, and a microscope objective images fluorescence onto a set of avalanche photodiodes, which operate in the analog mode. A high-gain transimpedance amplifier is used for each photodiode, providing high duty-cycle detection of fluorescence.

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