A Chandra High-Resolution X-ray Image of Centaurus A.

We present first results from a Chandra X-Ray Observatory observation of the radio galaxy Centaurus A with the High-Resolution Camera. All previously reported major sources of X-ray emission including the bright nucleus, the jet, individual point sources, and diffuse emission are resolved or detected. The spatial resolution of this observation is better than 1&arcsec; in the center of the field of view and allows us to resolve X-ray features of this galaxy not previously seen. In particular, we resolve individual knots of emission in the inner jet and diffuse emission between the knots. All of the knots are diffuse at the 1&arcsec; level, and several exhibit complex spatial structure. We find the nucleus to be extended by a few tenths of an arcsecond. Our image also suggests the presence of an X-ray counterjet. Weak X-ray emission from the southwest radio lobe is also seen, and we detect 63 pointlike galactic sources (probably X-ray binaries and supernova remnants) above a luminosity limit of approximately 1.7x1037 ergs s-1.

Detection of Septata intestinalis (Microsporidia) Cali et al. 1993 Using Polymerase Chain Reaction Primers Targeting the Small Submit Subunit Ribosomal RNA Coding Region.

Background: The microsporidian Septata intestinalis, recently suggested to be reclassified as Encephalitozoon intestinalis, is probably the second most common microsporidian isolated from AIDS patients after Enterocytozoon bieneusi. S. intestinalis causes a disseminated disease, including infections of the gastointestinal tract, whereas E. bieneusi is confined strictly to the gastrointestinal tract. It is important to differentiate between these two microsporidians, as only infections caused by S. intestinalis can, at this time, be effectively treated. Currently, diagnosis of infections caused by S. intestinalis can be achieved only by transmission electron microscopy. Methods and Results: In this study are described specific polymerase chain reaction primers for diagnosis of S. intestinalis infections based on the region coding for the small subunit ribosomal RNA cloned from a S. intestinalis isolate. These primers were tested for specificity on cloned ribosomal RNA sequences of different species of microsporidia, as well as on cultured samples of E. bieneusi, Encephalitozoon cuniculi, Encephalitozoon hellem and Vittaforma corneae (Nosema corneum), without showing any cross-amplification. By use of these polymerase chain reaction primers, eight different microsporidian isolates grown in culture and one diagnostic sample, collected as an ethanol-fixed duodenal-jejunal segment, were identified as S. intestinalis. Conclusion: These primers are powerful diagnostic tools and can enhance or replace traditional methods used to diagnose this microsporidian.