Complexes from Trypanosoma brucei that exhibit deletion editing and other editing-associated properties.

Transcripts from many mitochondrial genes in kinetoplastids undergo RNA editing, a posttranscriptional process which inserts and deletes uridines. By assaying for deletion editing in vitro, we found that the editing activity from Trypanosoma brucei mitochondrial lysates (S.D. Seiwert and K.D. Stuart), Science 266:114-117,1994) sediments with a peak of approximately 20S. RNA helicase, terminal uridylyl transferase, RNA ligase, and adenylation activities, which may have a role in editing, cosediment in a broad distribution, with most of each activity at 35 to 40S. Most ATPase 6 (A6) guide RNA and unedited A6 mRNA sediments at 20 to 30S, with some sedimenting further into the gradient, while most edited A6 mRNA sediments at >35S. Several mitochondrial proteins which cross-link specifically with guide RNA upon UV treatment also sediment in glycerol gradients. Notably, a 65-kDa protein sediments primarily at approximately 20S, a 90-kDa protein sediments at 35 to 40S, and a 25-kDa protein is present at <10S. Most ribonucleoprotein complexes that form with gRNA in vitro sediment at 10 to 20S, except for one, which sediments at 30 to 45S. These results suggest that RNA editing takes place within a multicomponent complex. The potential functions of and relationships between the 20S and 35 to 40S complexes are discussed.

Intrauterine transmission of Borrelia burgdorferi in dogs.

To determine whether intrauterine transmission of Borrelia burgdorferi could exist in dogs, 10 female Beagles were inoculated intradermally with approximately 1,000 B burgdorferi on day 1 of proestrus; inoculation was repeated every 2 weeks during the gestation period. Ten female control Beagles were similarly inoculated with phosphate-buffered saline solution. Prior to the start of the study, all females and 3 males used for breeding were seronegative for B burgdorferi on the basis of results of the indirect fluorescent antibody test and immunoblot (western analysis. Similarly, results of culture of blood for B burgdorferi were negative. All 20 of the females were bred naturally. Blood samples were collected weekly for serologic testing and culture. Blood samples were obtained from live pups on day 1 of life, then weekly until pups were 6 weeks old when they were euthanatized. Tissues were obtained for culture and testing by use of polymerase chain reaction (PCR). Of 10 spirochete-inoculated (SI) females, 8 became infected with B burgdorferi as evidenced by spirochete culture results and/or PCR-detected B burgdorferi DNA in the tissues of females or their pups. Of the 10 SI females, 8 delivered litters (3 to 7 pups) that had at least 1 neonatal or 6-week-old pup with B burgdorferi DNA-positive tissues (by PCR), and spirochetes were cultured from tissues from pups of 2 litters.(ABSTRACT TRUNCATED AT 250 WORDS)

Borrelia burgdorferi infection in dairy cows, rodents, and birds from four Wisconsin dairy farms.

A combination of culture and subsequent spirochete identification with the polymerase chain reaction technique was used to identify cows, rodents, and birds infected with Borrelia burgdorferi. Animals were trapped on four Wisconsin dairy farms during the summer of 1990. Farms 1 and 2 were located in counties nonendemic for Lyme disease and Farms 3 and 4 were located in counties endemic for Lyme disease. The results of the rodent and bird samples were as follows given as the number yielding organisms number tested: Farm 1, 1/17 Mus musculus and 2/52 Peromyscus domesticus; Farm 2, 4/49 M. musculus, 1/2 P. maniculatus, 1/1 P. leucopus, and 1/35 P. domesticus; Farm 3, 0/27 M. musculus, 0/5 P. leucopus, 0/12 P. maniculatus and, 3/58 P. domesticus; and Farm 4, 1/24 M. musculus, 2/19 P. leucopus, 1/12 Microtus pennsylvanicus, and 0/17 P. domesticus. One P. leucopus and one M. musculus from Farm 2 were pregnant and fetal tissues from both were positive. Cow blood sample results were as follows: Farm 1, 7/47 in July, and 2/45 in August; Farm 2, 0/28 in August and 0/23 in October; Farm 3, 0/13 in July and 1/18 in August 29; and Farm 4, 3/45 in August. Ticks were found on rodents on Farm 4 and on one bird on Farm 3. Spirochetemic cows, rodents, and birds were found in non-Lyme endemic counties suggesting that alternate modes of transmission other than by ticks may be important. Transplacental transmission was shown in M. musculus and P. leucopus.