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Juan Antonio Ramirez‐Merlano Víctor Mauricio Medina‐Robles Pablo Emilio Cruz‐Casallas 《Aquaculture Research》2011,42(6):738-745
The effects of straws volume, cryoprotectants and thawing temperatures were evaluated on the sperm quality of cachama blanca Piaractus brachypomus (Cuvier), an important Colombian fish species. Sexually mature fish were induced to ovulation or spermiation with a carp pituitary extract. A pool of suitable sperm samples was diluted in glucose, egg yolk, dimethyl sulphoxide (DMSO‐10%), methanol (MET‐10%) or ethylene glycol (ETG‐5%) and packed in 0.5, 2.5 or 5.0 mL straws and frozen in nitrogen vapour. The thawing process was performed in a 35 or an 80 °C water bath. The fertility was evaluated after 6 h post fertilization. The highest motility percentage (33 ± 3%) was observed with sperm cryopreserved with DMSO, packed in 5 mL straws and thawed at 35 °C. The treatments with DMSO and MET packed in 0.5 and 5.0 mL straws and thawed at 35 °C showed the highest fertility (higher than 71%) and the lowest fertility was obtained with MET‐2.5 mL (9 ± 5%). In all the treatments, a significant decrease in the sperm quality was observed at 80 °C. Sperm cryopreserved with DMSO‐10% or MET‐10%, packed in 2.5 or 5.0 mL straws are suitable to achieve acceptable fertilization and to fertilize high amounts of eggs. 相似文献
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Robles Jimenez Lizbeth E. Ruiz Perez Jose A. Nicolas Di Lorenzo Chay Canul Alfonso J. Ramirez-Rivera Julio Cesar Villegas-Estrada Daniela Vargas-Bello-Pérez Einar Gonzalez-Ronquillo Manuel 《Tropical animal health and production》2020,52(3):1257-1267
Tropical Animal Health and Production - Currently for the reduction of methane (CH4) emissions are using fodder rich in condensed tannins, however, not yet known exactly how they act in the rumen... 相似文献
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Lucas R Robles A García MT Alvarez De Cienfuegos G Gálvez A 《Journal of agricultural and food chemistry》2001,49(1):79-85
The hyphomycete Chalara (syn. Thielaviopsis) paradoxa produces endoglucanase activity during the late trophophase. The low molecular mass (35 kDa) endoglucanase purified from cultured broths works optimally at 37 degrees C and pH 5.0. The enzyme inactivates at pH below 3.0 and also at temperatures of 50 degrees C or higher, but it is stable at lower temperatures, including refrigeration temperature and freezing. The enzyme is inhibited by detergents, by EDTA, and by the divalent cations Hg(2+) and Ag(2+). It is also inhibited to some extent by 10 mM Zn(2+), Fe(2+), and Mg(2+), but it is stimulated by Mn(2+). Enzyme activity is not affected by reducing agents. In the presence of low concentrations of water miscible organic solvents (20%) endoglucanase activity is inhibited by 7% (for methanol) to 50% (for acetonitrile), and it is totally inhibited at higher solvent concentrations (50%). Enzyme activity is not affected by the water immiscible solvent ethyl acetate. Carboxymethylcellulose is the preferred substrate (K(m(app)) = 8.3 g/L; V(max(app)) = 1.1 microM/min). Hydrolysis of crystalline cellulosic substrates is very limited, but it is greatly enhanced by phosphoric acid swelling. The purified enzyme shows no activity toward disaccharides or aryl-glucosides. Its activity is inhibited by cellobiose. 相似文献
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A. Bautista-Cruz R. Carrillo-Gonzlez M.R. Arnaud-Vias C. Robles F. de Len-Gonzlez 《Soil & Tillage Research》2007,96(1-2):342-349
This study examined the variations in soil physical, chemical and biological properties from Agave angustifolia fields in three sites with different topographic conditions (valley, hill and mountain), in Oaxaca, Mexico, associated with the tillage systems, disk ploughing (DP), animal drawn ploughing (ADP) and minimum tillage (MT), respectively. Plant ages were 1.5–3.5 years (class 1), 3.6–5.5 years (class 2) and 5.6–7.5 years (class 3). Soil samples were taken at two soil depths (0–20 and 21–40 cm) from plots of 4000 m2 within each site and plant age classes, during the spring of 2005. The main changes in soil properties were found in the mountain site. Soil bulk density (2.0 g cm−3), cone penetration resistance (CPR) (3.96 MPa), 0.7 and 1.0 mm water stable aggregates (WSA) (28.3 g kg−1 and 102.2 g kg−1, respectively) were higher in the mountain site than in the hill and valley fields. This result is consistent with the rocky substrate beneath the shallow soil. Soil organic carbon (SOC) (23.9 g kg−1), available N (23.1 mg kg−1) and soil microbial biomass carbon (SMBC) (969.6 μg g−1) at the mountain site showed the highest values, suggesting that MT practiced in this topographic condition favours the organic matter accumulation and biological activity. Soil microbial biomass carbon and SOC seem to be the soil properties that were mainly affected by the sites and soil management associated with them. For the three sites, SOC, POlsen, available N, exchangeable Na+ and SMBC were higher at 0–20 cm depth than at 21–40 cm depth within each site. Exchangeable Ca2+ and K+, POlsen and CPR increased with plant age. In contrast, available N decreased. Soil chemical properties were more affected by the age of the plant than physical and biological properties. Results reported here represent a reference of the fertility properties of soils cultivated with A. angustifolia, which could be used in further studies focused on management and tillage systems. 相似文献
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Brucellosis in sheep, caused by Brucella ovis, is primarily a chronic infectious disease of rams with epididymitis as its most characteristic lesion. Six hundred rams from an infected farm were clinically and serologically examined once a year, over a 3-year period. An increase from 2.1% to 6.3% in the prevalence of animals serologically positive to B. ovis occurred over the 3 years. However, the prevalence of rams with lesions in the reproductive tract declined from 14.2% to 6.5% in the third year following one year of strict culling of clinically affected and rams that were serologically positive for B. ovis. Clinical lesions found in the 179 affected rams fell into two main categories: rams with epididymitis and rams with affected lymph nodes. These results suggest that the prevalence of the disease relates mainly to the sexual activity of the animal and not to age in itself. A single cull based on the results of clinical examination and serological test results was unable to decrease the prevalence of B. ovis in an extensive Corriedale sheep flock. 相似文献
8.
A major challenge to the widespread production of transgenic, knockout and knockdown zebrafish has been the absence of a simple and effective procedure for introducing macromolecules into the fertilized egg. None of the existing techniques for gene transfer in fish embryos has proven to be a major advance over cytoplasm microinjection, which is a technically demanding and time‐consuming procedure. This report addresses this need, considering that the development of protocols for lipid‐based transfection with fish embryos would considerably simplify gene transfer in this complex biological model. In this study, lipid‐based transfection with two different reporter vectors was carried out in zebrafish embryos at different developmental stages. The parameters tested included different plasmid/transfection reagent ratios as well as the influence of an added transfection enhancer reagent. When embryos were transfected in the blastula stage with a pEGFP‐N1 vector, more than 35% successfully incorporated the plasmid and expressed the fluorescent protein 24 h after transfection. The transfection enhancer did not show any significant effect in our experiments. This work presents an approach to implement this technique as a faster, cheaper and more practical alternative than microinjection. 相似文献
9.
Fermin Rivera Gloria Vilaclara Alfonso Lugo Pedro Ramirez Esperanza Robles Antonio Labastida 《Water, air, and soil pollution》1988,37(1-2):1-12
Protozoological and physicochemical analyses were performed in a waste stabilization pond at Sto. Tomas Atzingo, a small town near Mexico City, in order to discern the internal dynamics of the pond water through the study of the spatial distribution pattern of flagellates and the parallel water volume distribution pattern of some selected physicochemical determined parameters. The statistical method applied to the data obtained was by cluster analysis. The results showed a slight trend to heterogeneity in the system, when it was evaluated through the physicochemically determined parameters. On the other hand, the spatial distribution pattern of the flagellates pointed out a remarkable heterogeneity in the pond. In systems like the one studied where the main feature is an organic matter overload, such a difference in findings indicates a low correlation between the biological parameters, in this case the flagellates, and the physicochemical variables, that should be considered when evaluating the water quality of such systems, either through the physicochemical, the biological or both scopes. 相似文献
10.
Removal of hemangiosarcoma cells from canine blood with a cell salvage system and leukocyte reduction filter 下载免费PDF全文