In this study, we characterized a novel Babesia bovis cDNA clone obtained by immunoscreening the cDNA expression phage library with B. bovis-infected bovine serum. The genetic analyses showed that it ...contained an open reading frame of 993 bp, which was considered to encode B. bovis L-lactate dehydrogenase (BbLDH: E.C. 1.1.1.27) because of the strikingly high amino acid identities of its gene product to the LDHs of Plasmodium falciparum and Toxoplasma gondii. Immunological analyses with the anti-recombinant BbLDH mouse serum showed that 36 kDa of the native BbLDH was expressed not only in the cytoplasm of intra- and extraerythrocytic parasites but also along the membrane of infected erythrocytes. The kinetic properties of recombinant BbLDH proved a certain enzymatic activity of LDH, and the activity was significantly inhibited by the addition of gossypol, a competitive inhibitor of protozoan LDHs. Moreover, 100 microM of the gossypol irretrievably arrested the in vitro growth of B. bovis. The results demonstrated that BbLDH provides a suitable drug target for the design of novel babesial chemotherapeutics.
We examined the detailed cellular localization of the rhoptry-associated protein-1 (RAP-1) of Babesia bovismerozoites by the post-embedding method of immuno-electron microscopy (IEM) using the ...anti-RAP-1monoclonal antibody (mAb) 1C1 in order to substantiate the result in our previous report by an indirectimmunofluorescent antibody test and the pre-embedding method of IEM. RAP-1 slightly distributed only incytoplasm of merozoites, especially around the nucleus, but not in the rhoptry organelle at an early stageafter invasion into a red blood cell. Then, the RAP-1 was accumulated in the rhoptry organelle and was alsofound in the iRBC cytoplasm, which suggests that synthesis and release of RAP-1 may occur in the iRBC.Finally, the RAP-1 was found within and around merozoites after the breakdown of the iRBC. The results ofthe present study suggest that the RAP-1 of B. bovis merozoites functions not only in the invasion into RBCbut also in the escape from iRBC.
Recombinant antigen-based enzyme-linked immunosorbent assay (ELISA) was developed for the serological diagnosis of
Babesia bigemina infection by using a full-length
B. bigemina rhoptry-associated ...protein 1 (rRAP-1) and the truncated C-terminal RAP-1 (rRAP-1/CT). While the rRAP-1 showed cross reactivity between
B. bigemina- and
Babesia bovis-infected bovine sera, the rRAP-1/CT was highly specific to
B. bigemina-infected bovine sera and proved useful in the detection of sequential sera collected from an experimentally infected cow during the acute and latent infection. The high yield of soluble rRAP-1/CT and its diagnostic specificity demonstrate its potential in the diagnosis of
B. bigemina infection. Its usefulness for epidemiological investigation is currently being evaluated.
Babesia parasites are major hemoprotozoa in a variety of animals, and the infections cause great economic losses in the livestock or companion animal industry worldwide. In this study, using anti-B. ...rodhaini immune serum, we examined the immunogenic proteins of B. rodhaini, which is a rodent species of Babesia and has been used as an experimental animal model for other babesioses. Immunological analyses with the immune serum showed wide localization in the parasite body as well as around the surface of infected red blood cells and the existence of at least 15 antigens. In addition, 10 groups of immunoreactive cDNA clones were obtained from a B. rodhaini-cDNA expression phage library by the immunoscreening technique with the immune serum. It is hoped that these results will supply useful materials for the development of babesial subunit vaccines.
To investigate whether the fertilizing ability is changed during tansit of spermatozoa in the cauda epididymis in BALB/c mouse which is known as a low in vitro fertilization (IVF) rate, we examined ...the capacitation rates of spermatozoa collected from 3 regions of the cauda epididymis by chlortetracycline (CTC) fluorescence assay. In addition, their fertilizing ability was examined by IVF with cumulus-intact and cumulus-free mouse eggs. Spermatozoa immediately collected from the cauda epididymis showed no significant differences in capacitation rates (the proportion of spermatozoa having a fluorescence-free dark band in the postacrosomal region; B pattern) estimated by CTC test among regions. Nevertheless, the capacitation rates in the proximal region were significantly (P0.05) higher than that in distal region at 60 min of incubation and the middle region at 120 min of incubation. Non-preincubated spermatozoa regardless of the collection regions in the cauda epididymis showed signs of low fertilizing ability in cumulus-intact (9-10%) and cumulus-free (0-4%) mouse eggs at 6 h after insemination. After 2 h sperm preincubation, fertilization rates of spermatozoa collected from the proximal and distal regions were only slightly increased (26-44%) but that of middle region was greatly increased in both cumulus-intact (68%) and cumulus-free (61%) mouse eggs. These results suggest that the fertilizing ability of BALB/c mouse spermatozoa is changed during transit of the cauda epididymis, and the spermatozoa in the middle region or the cauda epididymis could be utilized efficiently for IVF in the BALB/c mouse strain
In this study, we characterized a novel
Babesia bovis cDNA clone obtained by immunoscreening the cDNA expression phage library with
B. bovis-infected bovine serum. The genetic analyses showed that it ...contained an open reading frame of 993
bp, which was considered to encode
B. bovis
l-lactate dehydrogenase (BbLDH: E.C. 1.1.1.27) because of the strikingly high amino acid identities of its gene product to the LDHs of
Plasmodium falciparum and
Toxoplasma gondii. Immunological analyses with the anti-recombinant BbLDH mouse serum showed that 36
kDa of the native BbLDH was expressed not only in the cytoplasm of intra- and extraerythrocytic parasites but also along the membrane of infected erythrocytes. The kinetic properties of recombinant BbLDH proved a certain enzymatic activity of LDH, and the activity was significantly inhibited by the addition of gossypol, a competitive inhibitor of protozoan LDHs. Moreover, 100
μM of the gossypol irretrievably arrested the in vitro growth of
B. bovis. The results demonstrated that BbLDH provides a suitable drug target for the design of novel babesial chemotherapeutics.
Species composition and seasonal abundance of tabanid population were investigated at a key farm in Pathumthani province from June 1994 to July 1995. Tabanids were collected with insect nets and a ...mosquito net trap every 10-day interval. From the study, the tabanids were found throughout the year. And they comprised of more than five species belong to the genus Tabanus, of which T. megalops (65.49 percent of the total number 768) was predominant, T. rubidus, T. rufiscutellatus, T. striatus and T. oxybeles occupied 29.69, 3.13, 0.65 and 0.26, respectively. They were abundant from June through October and gradually decreased towards March, and increased again in April, according to the meterological data, tabanids were abundant in wet season rather than dry season.
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