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1.
Leal-Hernandez M Díaz-Aparicio E Pérez R Andrade LH Arellano-Reynoso B Alfonseca E Suárez-Güemes F 《Comparative immunology, microbiology and infectious diseases》2005,28(1):63-70
It is a dogma, that RB51 vaccination does not induce antibodies that interfere with Brucellosis diagnosis, therefore any animal positive to serological test is considered as an infected animal. To determine protection against Brucellosis virulent field strain, 35 pregnant cows from a free-Brucellosis herd, previously vaccinated as calves with 1 x 10(10) CFU of RB51, were revaccinated with RB51 reduced dose, and then introduced into a herd with an active outbreak. Seventeen cows resulted positive in card test after revaccination. All 35 pregnant revaccinated cows had normal parturition; nevertheless, RB51 vaccine strain was isolated from milk and vaginal exudates from two cows after delivery at day 120 post-revaccination. At 150 days post-revaccination, two cows were positives to card and rivanol test and the field virulent strain was isolated. Revaccination with a reduced dose of RB51 in endemic zones did not cause abortion and protected 94% of animals against field infection, but caused an atypical response to conventional serological tests. 相似文献
2.
Saltos Luis Alberto Corozo-Quiñones Liliana Pacheco-Coello Ricardo Santos-Ordóñez Efrén Monteros-Altamirano Álvaro Garcés-Fiallos Felipe R. 《Phytoparasitica》2021,49(1):113-122
Phytoparasitica - Root and crown rot (RCR) caused by Phytophthora capsici is present in all crop production areas of pepper and chili worldwide. This pathogen was recently reported at the Pacific... 相似文献
3.
Herrera E Rivera A Palomares EG Hernández-Castro R Díaz-Aparicio E 《Tropical animal health and production》2011,43(6):1069-1070
The purpose of this study is to determine the etiology of abortions presented in a goat herd declared as free of brucellosis
and vaccinated with RB51 located in Mexico. The serological diagnosis of brucellosis in 33 animals was performed. The study
included three goats that aborted in the last third of gestation and 15 goats that gave birth normally; samples of milk and
vaginal exudate were subjected to bacteriological study. All animals were negative for serological diagnosis, and isolation
of Brucella melitensis was achieved in a single goat from vaginal exudate. However, the particularity is that this goat was negative to the card,
indirect ELISA, and radial immunodiffusion tests. Isolation of a field strain was confirmed by biochemical test resistance
to rifampicin and PCR. It is concluded that a goat which aborted in the last third of gestation was found spreading B. melitensis through vaginal discharge despite being vaccinated with RB51 and seronegative for brucellosis. 相似文献
4.
Efrén Garcia-Ordiales Jorge Loredo Stefano Covelli José M. Esbrí Rocio Millán Pablo Higueras 《Journal of Soils and Sediments》2017,17(7):1893-1904
Purpose
The Almadén mining district has suffered long-term extraction activity, and this has left significant areas of decommissioned mining liabilities. Nowadays, the uncontrolled runoff and related erosion and transport of trace metal-enriched soils and sediments affect the whole freshwater ecosystem. The goal of this study was to distinguish geogenic from mining-related sources of trace metals in freshwater sediments, to understand their dispersion in the watershed, and, finally, to evaluate the potential environmental implications for future corrective plans.Materials and methods
Freshwater surface sediment samples were collected from ten points along the main streams of the watershed (nine inside the mining district and one control point outside the district). Sediments were air dried and analyzed by different standard methods for pH, total major and trace element concentrations, total organic carbon, and grain size. In addition to the determination of the enrichment factor, a multi-statistical approach was applied involving discriminant analysis, Student’s t test, and Mann-Whitney U analysis.Results and discussion
Sediments inside the district contained high levels of major and trace elements with respect to the control point. The predominance of fine fractions in these sediment samples appears to be one of the most important factors that affects trace metal concentrations. Among the trace elements, not only Hg but also As, Pb, and Zn are discriminative geochemical markers, thus allowing the identification of the different mining sources and their individual or combined impact throughout the district. Furthermore, the high enrichment factors obtained for As, Hg, Pb, and Zn with respect to the local background values highlight the persistent and severe impact from the decommissioned mines on the freshwater surficial sediments and their potential geoavailable risk for aquatic organisms.Conclusions
The geochemistry of freshwater sediments alone demonstrates that different contamination sources are recognizable within the mining district and these can be related to the specific decommissioned mines. In addition, the discrete sources can be clearly distinguished on the basis of the statistical analysis of the geochemical data. Despite the closure of the mines, stream sediments are still the main repository of trace metals within the district, and they are therefore a potential threat to the freshwater ecosystem.5.
6.
Pérez-Romero N Aguilar-Romero F Arellano-Reynoso B Díaz-Aparicio E Hernández-Castro R 《Tropical animal health and production》2011,43(5):901-903
Methods
The nasal exudate from 42 goats of the Mixteca Region in the state of Puebla, Mexico, was evaluated. A strain was isolated after 4 days of incubation. This strain was identified according to its phenotypic characteristics and by means of a species-specific polymerase chain reaction (PCR), as well as by sequencing of the amplified product. 相似文献7.
Productive and economic parameters of pigs supplemented from weaning to finishing with prebiotic and probiotic feed additives 
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下载免费PDF全文 Néstor Méndez‐Palacios Maximino Méndez‐Mendoza Felicitas Vázquez‐Flores José G. Castro‐Colombres J. Efrén Ramírez‐Bribiesca 《Animal Science Journal》2018,89(7):994-1001
Practical evidence suggests possible beneficial effects with the combined use of prebiotics and probiotics which can improve production parameters. The objective of the study was to investigate the addition of Saccharomyces cerevisiae (SC) as prebiotic and the combination of Lactobacillus spp. (L), Bacillus spp. (B) as probiotics on productive parameters and economic feasibility. Four hundred male pigs, hybrids of commercial genetic lines (Pietrain), were used: T1 = control group, T2 = 4 kg/tonne SC, T3 = 0.8 kg/tonne feed L and B, T4 = 4 kg/tonne SC + 0.8 kg/tonne L and B. Productive parameters were recorded in the treatment groups for four periods. Then, the viscera of five pigs per treatment were collected after slaughter to evaluate the histological changes and cytokine concentrations in the ileum. The weight gains of groups at 70–100, 100–125 and 125–150 days in the T4 group showed statistically increases (p < .05). Feed intake had a significant difference (p < .05) in T3 versus T1. The feed‐conversion ratio improved for all periods in the T4 group (p < .05). The eosinophil, mononuclear infiltration and cytokines (tumor necrosis factor‐α and interleukin‐6) in the mucosa were lower for treatments with probiotics. In conclusion, there was an economic benefit when using both prebiotics and probiotics in the diet of pigs from weaning to finishing. 相似文献
8.
Beatriz Arellano-Reynoso Francisco Suárez-Güemes Félix Mejía Estrada Fernando Michel-GómezFlores Rigoberto Hernández-Castro Rómulo Beltrán Acosta Efrén Díaz-Aparicio 《Tropical animal health and production》2013,45(2):695-697
A study was carried out in Pichucalco, Chiapas (Mexico) to determine whether recently calved cows or those that aborted shed Brucella. Serological diagnosis of brucellosis was made in all animals (209). Six of the cows that calved normally and two that aborted underwent a bacteriological study of milk and vaginal exudate. Brucella abortus was isolated from vaginal exudate samples in two 3- to 4-year-old seronegative first-birth cows that had calved normally. This was confirmed through bacteriological identification and PCR as a field strain and smooth phenotypes. We conclude that seronegative cows vaccinated with RB51 which calved normally and shed B. abortus in the vaginal exudate after calving could be a serious problem because these cows are overlooked in routine diagnoses and are a source of Brucella infection. 相似文献
9.
Luis Galarza Yasunori Akagi Kazumi Takao Chang Sun Kim Nitaro Maekawa Akihiro Itai Esther Peralta Efrén Santos Motoichiro Kodama 《Journal of General Plant Pathology》2015,81(3):201-210
Native Trichoderma spp. were isolated from agricultural fields in several regions of Ecuador. These isolates were characterized via morphological observation as well as molecular phylogenetic analysis based on DNA sequences of the rDNA internal transcribed spacer region, elongation factor-1α gene and RNA polymerase subunit II gene. Fifteen native Trichoderma spp. were identified as T. harzianum, T. asperellum, T. virens and T. reesei. Some of these strains showed strong antagonistic activities against several important pathogens in Ecuador, such as Fusarium oxysporum f. sp. cubense (Panama disease) and Mycosphaerella fijiensis (black Sigatoka) on banana, as well as Moniliophthora roreri (frosty pod rot) and Moniliophthora perniciosa (witches’ broom disease) on cacao. The isolates also showed inhibitory effects on in vitro colony growth tests against Japanese isolates of Fusarium oxysporum f. sp. lycopersici, Alternaria alternata and Rosellinia necatrix. The native Trichoderma strains characterized here are potential biocontrol agents against important pathogens of banana and cacao in Ecuador. 相似文献
10.
Arellano-Reynoso B Díaz-Aparicio E Leal-Hernández M Hernández L Gorvel JP 《Veterinary microbiology》2004,98(3-4):307-312
Brucella is responsible for one of the major worldwide zoonoses. Over the last century, several vaccines have been used against brucellosis. Among these, the rough vaccine Brucella abortus RB51 was introduced with the idea that it would not interfere with the diagnosis of brucellosis. Recently, RB51 has been isolated from milk and vaginal exudates from vaccinated cows, thus raising the possibility of extensive bacterial replication in these animals. We hypothesized that shedding of RB51 might be related to a change in its intracellular cell cycle. Therefore, we have compared the intracellular trafficking in CHO cells of the virulent B. abortus 2308 and two RB51 strains, the vaccinal strain and the one isolated from cow milk. Both RB51 strains were transiently observed in phagosomes characterized by the presence of the early endosomal marker EEA1 and then were found in cathepsin D-enriched lysosomal compartments, in which they eventually underwent degradation at later post-infection times. In contrast, the virulent 2308 strain replicated within the endoplasmic reticulum. These results suggest that a change in intracellular trafficking cannot account for Brucella shedding in adult vaccinated cows. 相似文献