We investigated the prevalence of virulent Rhodococcus equi in clinical isolates from 69 sporadic cases (60 men, 8 women, and 1 patient of unknown sex) in Chiang Mai, Thailand, between 1993 and 2001. Fifty were human immunodeficiency virus (HIV) positive, 3 were HIV negative, and HIV status was unknown for 16. Fifty-two (75%) of 69 isolates were strains of intermediate virulence that contained the virulence-associated 20-kDa antigen, and 17 isolates (25%) were avirulent. No virulent strains with the virulence-associated 15-17-kDa antigens were identified. R. equi was isolated from HIV-positive patients' houses and those of their neighbors: avirulent strains were widespread, but only 1 strain of intermediate virulence was isolated. R. equi strains of intermediate virulence were isolated from 4 (0.8%) of 500 submaxillary lymph nodes from apparently healthy pigs in Chiang Mai. The routes of R. equi acquisition should be investigated from the viewpoint of zoonosis and public health.

Influenza viruses infect vertebrates, including mammals and birds.Influenza virus reverse-genetics systems facilitate the study of the structure and function of viral factors. In contrast, less is known about host factors involved in the replication process. Here, we developed a replication and transcription system of the negativestrand RNA genome of the influenza virus in Saccharomyces cerevisiae, which depends on viral RNAs, viral RNA polymerases, and nucleoprotein (NP). Disruption of SUB2 encoding an orthologue of human RAF-2p48/UAP56, a previously identified viral RNA synthesis stimulatory host factor, resulted in reduction of the viral RNA synthesis rate. Using a genome-wide set of yeast single-gene deletion strains, we found several host factor candidates affecting viral RNA synthesis. We found that among them, Tat-SF1, a mammalian homologue of yeast CUS2, was a stimulatory host factor in influenza virus RNA synthesis. Tat-SF1 interacted with free NP, but not with NP associated with RNA, and facilitated formation of RNA-NP complexes. These results suggest that Tat-SF1 may function as a molecular chaperone for NP, as does RAF-2p48/UAP56. This system has proven useful for further studies on the mechanism of influenza virus genome replication and transcription. molecular chaperone ͉ replication ͉ RNA-dependent RNA polymerase ͉ nucleoprotein

Time-resolved hard X-ray photoelectron spectroscopy (trHAXPES) using microfocused X-ray free-electron laser (XFEL, hν = 8 keV) pulses as a probe and infrared laser pulses (hν = 1.55 eV) as a pump is employed to determine intrinsic charge-carrier recombination dynamics in La:SrTiO3. By means of a combination of experiments and numerical N-body simulations, we first develop a simple approach to characterize and decrease XFEL-induced vacuum space-charge effects, which otherwise pose a serious limitation to spectroscopy experiments. We then show that, using an analytical mean-field model, vacuum space-charge effects can be counteracted by pump laser-induced photoholes at high excitation densities. This provides us a method to separate vacuum space-charge effects from the intrinsic charge-carrier recombination dynamics in the time domain. Our trHAXPES results thus open a route to studies of intrinsic charge-carrier dynamics on picosecond time scales with lateral spatial resolution on the micrometer scale.

ABSTRACT. Rhodococcus equi was isolated from fecal and soil samples from four native Jeju horse farms and six Thoroughbred farms in Jeju, Korea. The isolates were examined for the presence of virulence-associated 15-17-kDa antigens (VapA) by colony blotting, using the monoclonal antibody 10G5, and for the gene encoding VapA by PCR. R. equi was isolated from all 36 soil samples collected from the 10 farms with between 5.0 × 10 2 and 7.5 × 10 4 colony-forming units (cfu) per gram of soil, and from 37 of 40 fecal samples with between 5.0 × 10 1 and 1.1 × 10 5 cfu per gram of feces. Virulent R. equi was isolated from seven farms and appeared in 2.0% of isolates (10 of 508). Of the 10 virulent isolates, four contained a 90-kb type II plasmid, which has been found in isolates from the Kiso native horses of Japan, and the other six contained a new variant, which did not display the EcoRI and EcoT22I digestion patterns of the 10 representative plasmids already reported (85-kb types I, II, III, and IV; 87-kb types I and II; 90-kb types I, II, III, and IV). We designated the new variant as the "90-kb type V" plasmid, because its EcoRI digestion pattern is similar to that of the 90-kb type II plasmid. This is the first report of the prevalence of virulent R. equi in Jeju, Korea. The same virulence plasmid type is found in both Korean and Japanese isolates, providing insight into the origin, ancestry, and dispersal of native horses in Korea and Japan.

Virulent Rhodococcus equi is an important pathogen in foals aged Key words: foal, Rhodococcus equi, soil, TennesseeRhodococcus equi is one of the most important bacterial pathogens in foals less than 3 months of age [1, 12,15,29]. Infections caused by this organism are c h a r a c t e r i z e d b y a c h r o n i c , s u p p u r a t i v e bronchopneumonia and/or enteritis [1, 12,15,29]. In horses, the disease is distributed worldwide, but little is known about the incidence of the infection in Tennessee, U. S. A.The discovery of virulence-associated antigens and virulence plasmids has permitted classification of the virulence of R. equi strains [23,30]. At least three virulence levels of R. equi have been identified: virulent, intermediate virulence, and avirulent [15]. Virulent R. equi is characterized by the presence of virulenceassociated 15-to 17-kDa antigens (VapA), and virulence plasmid DNA of 85-90 kb [23,30,33]. There are at least 11 virulence plasmid types (85-kb types I to IV, 87-kb types I and II, and 90-kb types I to V) present in VapA-positive R. equi from horses in the world by restriction fragment length polymorphism of plasmid DNAs [13,17,25,26,[31][32][33]. The virulent form has been found in pulmonary and/or intestinal lesions in foals and in the pulmonary lesions of AIDS patients (murine LD 50 =10 6 ) [28,30]. R. equi strains of intermediate virulence are identified by a virulence associated 20-kDa antigen (VapB) and virulence plasmid DNA of 79-100 kb [22]. The intermediate virulence form has been found in the submaxillary lymph nodes of pigs (murine LD 50 =10 7 ) and in the pulmonary lesions of AIDS patients [18,22]. In comparison, avirulent R. equi shows no evidence of either virulence-associated antigens or plasmid DNA (murine LD 50 >10 8 ), and is widespread in soil [15,29]. In recent studies, we have demonstrated geographic differences in the distributions of the virulenceassociated plasmids found in the Americas, Europe, Australia, Africa, Korea and Japan [2, 7-11, 13, 16, 17, 19, 25-27, 31-33, 35]. Most clinical isolates from the Americas, Australia, and Europe contain 85-kb type I or 87-kb type I plasmids [2, 7-11, 17, 19, 31]. The 85-kb type II plasmid is found only in French isolates and the 85-kb type III and type IV plasmids only in isolates from Texas [13,17,31]. These five types of virulence