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Tritrichomonas foetus is an extracellular parasite of the urogenital tract in cattle. It causes infertility and abortion, but there is no documented information on the susceptibility of bovine oocytes to the parasite, except by one article that claimed no effects of T. foetus on oocytes or embryos. The aim of the present study was to study the effects provoked by T. foetus when in interaction with bovine oocytes. Oocytes were obtained from cow ovaries and divided into two groups: (1) one group contained cumulus cells, whereas (2) a second group was denuded from these cells. Light microscopy, video microscopy and scanning electron microscopy (SEM) revealed that exposure of oocytes to T. foetus caused rapid adhesion of the trichomonads to cumulus cells and to the zona pellucida (ZP). Motile parasites were observed for 12 h. The ZP was completely damaged, and the parasites were able to infiltrate beneath the ZP and reached the oocytes directly when the oocytes were denuded of the cumulus cells. Both the oocytes and the cumulus cells exhibited morphological characteristics compatible with apoptosis after interaction with T. foetus, such as chromatin condensation, the presence of several cytoplasmic vacuoles, with intact cellular membranes and organelles. The results from this study demonstrate that when a large number of T. foetus interacts with oocytes in vitro damage and apoptosis are provoked in the cow's reproductive cells. The behavior of this parasite as one of the causes of cattle infertility is discussed. 相似文献
2.
Tritrichomonas foetus is an extracellular parasite of the reproductive tract in cattle. To investigate the cytopathic effects of T. foetus in deeper parts of the reproductive tract, a bovine primary oviduct epithelial cell system (BOECs) was developed. Reproductive tracts were obtained from cows and the effect of co-incubating T. foetus with BOECs was analyzed by scanning electron, transmission electron and fluorescence microscopy. Viability tests were performed using colorimetric methods, TUNEL (Terminal deoxynucleotidyltransferase-mediated dUTP nick-end labeling), fluorescein diacetate, propidium iodide, JC-1 and annexin-V. The results demonstrate that: (1) the in vitro oviduct epithelium is useful for interaction experiments with T. foetus; (2) T. foetus adheres to the BOECs as single separate cells, and later on the cells aggregate as large clusters; (3) the posterior region of the cell initiates the process of adhesion and forms filopodia and digitopodia; (4) T. foetus severely damages BOECs leaving imprints in the epithelial cells, wide intercellular spaces, and large lesions in the epithelium; and (5) T. foetus provokes bovine oviduct cell death by apoptosis and secondary necrosis. Our observations indicate the possibility that T. foetus can move through the reproductive tract to the oviduct and that infertility in cows can be mediated by an attack on the oviduct cells by T. foetus. 相似文献
3.
A. M. M. Barbosa I. O. Geraldi L. L. Benchimol A. A. F. Garcia C. L. Souza Jr. A. P. Souza 《Euphytica》2003,130(1):87-99
Two sets of tropical maize inbred lines, one derived from the BR-105 population and another derived from the BR-106 population,
were assayed for Amplified Fragment Length Polymorphism's (AFLP) and for Simple Sequence Repeat (SSR), in order to investigate
genetic distances among lines and their relationship to heterotic group assignment and single cross yield performance. Genetic
distances were on average greater for interpopulation than intrapopulation crosses for both AFLP and SSR. Cluster analysis
was in agreement with the original assignment for heterotic groups. Inbred line 16, derived from BR-106, was assigned to the
BR-105 set, in agreement with single cross yield performance from intra- and interpopulation crosses. However, the same pattern
was not observed for SSR where another two lines from BR-106 were also assigned to the BR-105 set. Correlation coefficients
of genetic distances (GD) with F1 grain yield and heterosis were high for BR-106 ×BR-106 crosses
(0.91** and 0.82** for AFLP and SSR, respectively), moderate for BR-105 × BR-105 crosses (0.52* for AFLP and SSR) and low for BR-105 × BR-106 crosses (0.29 and 0.16 for AFLP and SSR, respectively). The lower correlation
at interpopulation level was due to the smaller range of GD caused probably by a previous selection for combining ability.
General results showed that the AFLP molecular marker is efficient in assigning maize lines to heterotic groups and that AFLP-based
GD is suitable for predicting the maize single cross performance for intrapopulation crosses of broad-based populations. The
efficiency of SSR in assigning lines to heterotic groups and for predicting single cross performance was smaller than AFLP.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
4.
Context
Biodiversity in tropical region has declined in the last decades, mainly due to forest conversion into agricultural areas. Consequently, species occupancy in these landscapes is strongly governed by environmental changes acting at multiple spatial scales.
ObjectivesWe investigated which environmental predictors best determines the occupancy probability of 68 bird species exhibiting different ecological traits in forest patches.
Methods.We conducted point-count bird surveys in 40 forest sites of the Brazilian Atlantic forest. Using six variables related to landscape composition and configuration and local vegetation structure, we predicted the occupancy probability of each species accounting for imperfect detections.
ResultsLandscape composition, especially forest cover, best predicted bird occupancy probability. Specifically, most bird species showed greater occupancy probability in sites inserted in more forested landscapes, while some species presented higher occurrence in patches surrounded by low-quality matrices. Conversely, only three species showed greater occupancy in landscapes with higher number of patches and dominated by forest edges. Also, several species exhibited greater occupancy in sites harbouring either larger trees or lower number of understory plants. Of uttermost importance, our study revealed that a minimum of 54% of forest cover is required to ensure high (> 60%) occupancy probability of forest species.
ConclusionsWe highlighted that maintaining only 20% of native vegetation in private property according to Brazilian environmental law is insufficient to guarantee a greater occupancy for most bird species. We recommend that policy actions should safeguard existing forest remnants, expand restoration projects, and curb human-induced disturbances to minimise degradation within forest patches.
相似文献5.
Luciana Lasry Benchimol Tatiana de Campos Sérgio Augusto Morais Carbonell Carlos Augusto Colombo Alisson Fernando Chioratto Eduardo Fernandes Formighieri Lígia Regina Lima Gouvêa Anete Pereira de Souza 《Genetic Resources and Crop Evolution》2007,54(8):1747-1762
A common bean genomic library was constructed using the ‘IAC-UNA’ variety enriched for (CT) and (GT) for microsatellite motifs. From 1,209 sequenced clones, 714 showed microsatellites distributed over 471 simple and 243 compound motifs. GA/CT and GT/CA were the most frequent motifs found among these sequences. A total of 123 microsatellites has been characterized. Out of these, 87 were polymorphic (73.7%), 33 monomorphic (26.8%), and 3 (2.4%) did not amplify at all. In a sample of 20 common bean materials selected from the Agronomic Institute Germplasm Bank, the number of alleles per locus varied 2–9, with an average of 2.82. The polymorphic information content (PIC) of each marker varied from 0.05 to 0.83, with a 0.45 average value. Cluster and principal coordinate analysis of the microsatellite data were consistent with the original assignment of the germplasm accessions into the Andean and Mesoamerican gene pools of common bean. Low polymorphism levels detected could be associated with the domestication process. These microsatellites could be a valuable resource for the bean community because of their use as new markers for genetic studies. 相似文献
6.
Tritrichomonas mobilensis is an intestinal parasite of squirrel monkeys. There are few reports concerning the morphological aspects of this parasite. In addition, the taxonomic relationship between T. mobilensis and Tritrichomonas foetus, a serious pathogen that causes bovine and feline trichomonosis, has been questioned. For this reason, in the present study, we examined and compared both tritrichomonads with regard to their morphology, ultrastructure, endocytic activity and cytotoxicity when in the presence of host cells. Electron microscopy demonstrated consistent morphological differences between the hydrogenosomes of both parasites. Moreover, T. mobilensis and T. foetus had striking differences in their endocytic behavior. Thus, this work provides additional data that support the hypothesis that T. mobilensis is a distinct species from T. foetus. 相似文献
7.
We present observations on an unusual tetratrichomonad species isolated from preputial smegma of virgin bulls. Ultrastructural studies were performed using scanning and electron microscopy techniques. This protozoan presents four anterior flagella of unequal length and a recurrent one forming the undulating membrane. It shows one anterior nucleus, a Golgi complex, an axostyle, and a costa. The hydrogenosomes are rather elongated, seen in groups, and presenting different electron densities. Vacuoles of different sizes containing bacteria and material in process of digestion were frequently found. PCR was also used in order to compare the species herein described with other trichomonad species. The amplification products were seen only with primers TFR1 and TFR2 (specific to trichomonads), but not with TFR3 and TFR4 (specific to Tritrichomonas foetus), suggesting that although collected from the genital tract of the bull, this protist was not T. foetus. We propose that the appearance of these tetratrichomonads were probably due to the sodomy practiced among bulls. Concomitant contamination of preputial cavity with feces could explain the presence of the opportunistic organism. The observations presented here show the importance of the correct diagnostic when investigating samples obtained from the urogenital tract of cattle. We also suggest that this flagellate belongs to the species Tetratrichomonas buttreyi. 相似文献
8.
Genetic diversity in tropical maize inbred lines: heterotic group assignment and hybrid performance determined by RFLP markers 总被引：13，自引：0，他引：13
L. L. Benchimol C. L. de Souza Jr A. A. F. Garcia P. M. S. KONO C. A. Mangolin A. M. M. Barbosa A. S. G. Coelho A. P. de Souza 《Plant Breeding》2000,119(6):491-496
Tropical maize inbred lines, eight derived from a Thai synthetic population (BR‐105) and 10 from a Brazilian composite population (BR‐106), were assayed for restriction fragment length polymorphisms with 185 clone‐enzyme combinations. The aim of this study was to investigate genetic distances among tropical maize material and their relationship to heterotic group allocation and hybrid performance. Genetic distances (GDs) were on average greater for BR‐105×BR‐106 lines (0.77) than for BR‐106×BR‐106 (0.71) and for BR‐105×BR‐105 (0.69) lines. Cluster analysis resulted in a clear separation of BR‐105 and BR‐106 populations and was according to pedigree information. Correlations of parental GDs with single crosses and their heterosis for grain yield were high for line crosses from the same heterotic group and low for line combinations from different heterotic groups. Our results suggest that RFLP‐based GDs are efficient and reliable to assess and allocate genotypes from tropical maize populations into heterotic groups. However, RFLP‐based GDs are not suitable for predicting the performance of line crosses from genetically different heterotic groups. 相似文献
9.
Tritrichomonas foetus is an extracellular parasite of the reproductive tract in cattle. The mechanism by which T. foetus causes abortion in cattle is largely unknown. There are no studies of infection in the cow oviducts, almost all published papers are related to vagina infection and few articles focusing on the uterus. The aim of the present study was to establish a working model of bovine oviduct epithelial cells and submit these cells to Tritrichomonas foetus interaction. Twenty bovine oviducts were obtained from cows at a commercial abattoir and T. foetus was injected through the isthmus into the oviduct lumen. The whole oviduct was analyzed by scanning and transmission electron microscopy. The results reported here demonstrate that: (1) fresh whole oviducts can be used as a good model to study parasite-host cell interaction; (2) cow oviduct epithelium has been shown to consist of two cell types: ciliated and nonciliated secretory cells, and T. foetus displayed great specificity for the nonciliated cells localized in the deeper oviduct folds; (3) T. foetus adheres as single separate cells, and maintains the flagella externalized; (4) differently from T. vaginalis, T. foetus does not change its shape during the adhesion process; and (5) oviduct cells exhibited morphological characteristics of apoptosis after trichomonadal interaction. 相似文献
10.
Luciana Lasry Benchimol Tatiana de Campos Sérgio Augusto Morais Carbonell Carlos Augusto Colombo Alisson Fernando Chioratto Eduardo Fernandes Formighieri Lígia Regina Lima Gouvêa Anete Pereira de Souza 《Genetic Resources and Crop Evolution》2007,54(8):1861-1762
A common bean genomic library was constructed using the ‘IAC-UNA’ variety enriched for (CT) and (GT) for microsatellite motifs.
From 1,209 sequenced clones, 714 showed microsatellites distributed over 471 simple and 243 compound motifs. GA/CT and GT/CA
were the most frequent motifs found among these sequences. A total of 123 microsatellites has been characterized. Out of these,
87 were polymorphic (73.7%), 33 monomorphic (26.8%), and 3 (2.4%) did not amplify at all. In a sample of 20 common bean materials
selected from the Agronomic Institute Germplasm Bank, the number of alleles per locus varied 2–9, with an average of 2.82.
The polymorphic information content (PIC) of each marker varied from 0.05 to 0.83, with a 0.45 average value. Cluster and
principal coordinate analysis of the microsatellite data were consistent with the original assignment of the germplasm accessions
into the Andean and Mesoamerican gene pools of common bean. Low polymorphism levels detected could be associated with the
domestication process. These microsatellites could be a valuable resource for the bean community because of their use as new
markers for genetic studies.
Electronic supplementary material The online version of this article (doi: ) contains supplementary material, which is available to authorized users.
An erratum to this article can be found at 相似文献
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