An extender solution for the short‐term storage of Litopenaeus vannamei sperm to be used in artificial insemination     

Karina Morales‐Ueno  Hugo H Montaldo  Alfonso Martínez Ortega  Carmen G Paniagua‐Chávez  Héctor Castillo‐Juárez 《Aquaculture Research》2013,44(8):1254-1258

Some shrimp hatcheries use artificial insemination (AI) to improve the male to female ratio in their breeding populations. We describe a sperm extender solution, which allows the short‐term storage of diluted sperm in Litopenaeus vannamei, and its use in an artificial insemination process. We also evaluate its fertilization capacity. An AI experiment was designed using two, one, or half spermatophore segments. We tested four treatments involving three different male:female ratios: Natural mating (1:1), Regular and Regular diluted (1:2) and Half diluted (1:4). Data analysis revealed that the number of nauplii produced per mating was affected by treatment, with Regular (158 420) performing better than Half diluted (112 864) (P < 0.05), but with no differences between the latter and Regular diluted (130 340) (P > 0.05). A binomial variable named female success (FS) was defined as successful when the number of nauplii obtained per mate was ≥25 000. Analysis showed differences for FS across treatments (P < 0.001), but not between Regular (79.2%), the hatchery conventional AI technique and Half diluted (60.4%), maybe due to sample size. Since the number of nauplii per mate is crucial to consider AI successful, it is necessary to improve this AI technique before it can be used in the shrimp industry.  相似文献   

Sodium Chloride Effects on Water and Nutrient Uptake Efficiency in Sarcocornia fruticosa Containerized Production     

Pedro García-Caparrós  Alfonso Llanderal 《Communications in Soil Science and Plant Analysis》2016,47(20):2306-2314

The ability to produce native plants well adapted to the saline conditions without the production of nutrient-rich runoff will be a boon to nurseries hoping to reduce their environmental contamination impact and water use while at the same time producing quality plants to be used in the restoration of saline lands. Sarcocornia fruticosa plants were grown for 8 weeks in plastic containers with a source of sphagnum peat moss and perlite (80:20 v/v) to evaluate the effect of two salinity levels (2.0 (low-salinity treatment) and 7.5 dS m^?1 (high-salinity treatment)) on plant growth, nutrient concentration in leachate and water and nutrient uptake efficiency and their losses. Leachate was collected to determine the runoff volume and composition, which included nitrate-nitrogen (NO₃^–N), phosphate-phosphorus (PO₄^3–P) and potassium (K⁺) concentrations. Plant dry weight (DW) and nutrient content were determined in plants at the beginning and at the end of the experiment to establish the nutrient balance. Increasing salinity levels of irrigation water did not reduce either the plant DW or the water-use efficiency (WUE), but increased the volume of leachate per plant. The nutrient concentrations in leachates without significant differences between salt treatments exceeded the thresholds established by environmental guidelines, leading to a great risk of pollution. Based on nutrient balance, the irrigation with a higher salinity level reduced the plant nutrient uptake efficiency (10%, 18% and 12% for nitrogen (N), phosphorus (P) and potassium (K), respectively) and increased the nutrient losses (6% N, 7% P and 8% K), resulting in the recommendation to grow this species with the low salinity level based on the highest nutrient-use efficiency and the lowest levels of nutrient losses.  相似文献   

Leptospirosis in pigs,dogs, rodents,humans, and water in an area of the Colombian tropics     

Alfonso Calderón  Virginia Rodríguez  Salim Máttar  Germán Arrieta 《Tropical animal health and production》2014,46(2):427-432

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Relevance of ovarian follicular development to the seasonal impairment of fertility in weaned sows     

Tania P. Lopes  Jonatan Sanchez-Osorio  Alfonso Bolarin  Emilio A. Martinez  Jordi Roca 《Veterinary journal (London, England : 1997)》2014,199(3):382-386

A field study was conducted to estimate seasonal differences in follicular development in weaned sows and to evaluate the implication of these differences on seasonal infertility. A total of 110 sows were selected at weaning during winter–spring (WS, n = 58) and summer–autumn (SA, n = 52). Ovaries were scanned once daily from weaning to the onset of oestrus and twice daily from then until ovulation. Six sows during WS were removed from study for not showing growing follicles at weaning. Oestrus was evaluated twice daily from day 1 after weaning to day 14 post-weaning. One of 52 (1.9%) sows in WS and 9/52 (17.3%) in SA showed no signs of oestrus within 14 days of weaning (P < 0.05). The diameters of the follicles at weaning, at the onset of oestrus and just before ovulation were smaller (P < 0.01) in SA sows than in WS sows. There were fewer follicles in SA sows than in WS sows just before ovulation (P < 0.05). Fifty of 51 (98.0%) sows in WS and 31/43 (72.1%) sows in SA experienced a weaning-to-oestrus interval (WOI) of 3–6 days (P < 0.05). Fifty-one of 52 (98.1%) sows in WS and 43/52 (82.7%) sows in SA were inseminated; the percentage of pregnant sows that failed to farrow was lower in WS (1/51, 2.0%) than in SA (5/43, 11.6%; P < 0.05). The percentage of farrowed sows was greater in WS (46/51, 90.2%) than in SA (32/43, 74.4%; P < 0.05). Sows in WS had on average 1.5 more piglets than sows in SA (P < 0.05). Sows with a WOI of 3–6 days had lower rates of pregnancy losses (P < 0.05) and higher farrowing percentages (P < 0.01) than those with a WOI > 6 days, irrespective of season.  相似文献   

Astrocytes potentiate transmitter release at single hippocampal synapses   总被引：1，自引：0，他引：1  

Perea G  Araque A 《Science (New York, N.Y.)》2007,317(5841):1083-1086

Astrocytes play active roles in brain physiology. They respond to neurotransmitters and modulate neuronal excitability and synaptic function. However, the influence of astrocytes on synaptic transmission and plasticity at the single synapse level is unknown. Ca(2+) elevation in astrocytes transiently increased the probability of transmitter release at hippocampal area CA3-CA1 synapses, without affecting the amplitude of synaptic events. This form of short-term plasticity was due to the release of glutamate from astrocytes, a process that depended on Ca(2+) and soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) protein and that activated metabotropic glutamate receptors (mGluRs). The transient potentiation of transmitter release became persistent when the astrocytic signal was temporally coincident with postsynaptic depolarization. This persistent plasticity was mGluR-mediated but N-methyl-d-aspartate receptor-independent. These results indicate that astrocytes are actively involved in the transfer and storage of synaptic information.  相似文献   

Development. Electrically driven insulation in the central nervous system     

Araque A  Navarrete M 《Science (New York, N.Y.)》2011,333(6049):1587-1588

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Biodegradation of viticulture wastes by Pleurotus: a source of microbial and human food and its potential use in animal feeding     

Sánchez A  Ysunza F  Beltrán-García MJ  Esqueda M 《Journal of agricultural and food chemistry》2002,50(9):2537-2542

The bioconversion of vineyard pruning and grape pomace by Pleurotus spp. using a solid state fermentation (SSF) was evaluated. Fruiting body production and chemical changes in the substrates after harvesting were measured. Biological efficiency and bioconversion ranged from 37.2 to 78.7% and from 16.7 to 38.8%, respectively. The best substrates for mycelial growth and mushroom yield were the mixtures with higher vineyard pruning content. Inclusion of pruning content had higher phenolic components and total sugars, better C/N ratio, and lower crude fat and total nitrogen than pomace. On the contrary, mycelium grew more slowly and scarcely in all treatments with 100% grape pomace. Moisture, protein, fat, and lignin contents were generally higher in mixtures with higher pomace proportion, whereas neutral detergent fiber, hemicellulose, and cellulose contents were higher with pruning content. Pleurotus strains may act depending on the availability of fiber fractions of substrate, and dynamic changes in digestion might occur as these fractions change during fungal growth. The recycling of viticulture residues through SSF by Pleurotus has great potential to produce human food and yields an available high-fiber feed for limited use in ruminants.  相似文献   

Reproductive Biology in Wild and Silvicultural Managed Populations of Escontria chiotilla (Cactaceae) in the Tehuacán Valley, Central Mexico     

Brenda Oaxaca-Villa  Alejandro Casas  Alfonso Valiente-Banuet 《Genetic Resources and Crop Evolution》2006,53(2):277-287

Reproductive biology of the columnar cactus Escontria chiotilla was analysed in wild and silvicultural managed populations in the Tehuacán Valley, Central Mexico, where this cactus is under domestication because of its edible fruits. Anthesis is diurnal, flowers opening between 8:00 and 17:00 h, the period between 12:00 and 13:00 appearing to be crucial in pollination success since at this time the maximum opening of flowers, turgidity of stigma, and activity of flower visitors, as well as the highest nectar production and pollen release occur. The bees Apis mellifera, Bombus pensylvanicus and Xylocopa mexicanorum, and the hummingbirds Amazilia violiceps, Cynanthus sordidus and Cynanthus latirostris were the most frequent flower visitors during the crucial period, and were observed contacting both stamens and stigma of E. chiotilla. No differences were found in anthesis nor in flower visitors among both population types. Distances separating the populations studied and bridges of individuals of E. chiotilla between them are within the radius that bees and hummingbirds may travel, indicating that spatial barrier to pollen flow are unlikely. Breeding system is self-incompatible. Production of flowers occurs during the whole year in both population types, allowing continual pollen flow among them. This observation confirms reports of high gene flow among the populations studied in previous population genetics studies. The high pollen flow among wild and managed population explains that however the occurrence of artificial selection, the process of domestication is in incipient stages presumably because gene flow counteracts effects of artificial selection.  相似文献   

Estimation of area burned by forest fires in Mediterranean countries: A remote sensing data mining perspective   总被引：1，自引：0，他引：1  

Carmen Quintano  Alfonso Fernández-Manso 《Forest Ecology and Management》2011,262(8):1597-1607

Forest fires throughout the world result in tree mortality that can cause substantial timber and carbon losses. There is a critical need to map the areas burned by such fires to guide forest management decisions. Moderate Resolution Imaging Spectroradiometer (MODIS) satellite imagery provides inexpensive and frequent coverage over large areas, facilitating forest health monitoring. In this study a MODIS post-fire image at a spatial resolution of 250 m serves as the starting point of an image mining based method. It involves three algorithms: modeling as a sum of Gaussian functions, kernel based smoothing, and adaptive thresholding. Adaptive thresholding serves as the reference to be compared to the image mining based method. Three spectral indices specifically designed for burned area identification have been used: the Burned Area Index (BAI), the Burned Area Index adapted to MODIS bands (BAIM), and the Normalized Burn Ratio (NBR). The κ statistic is applied to quantify the accuracy of the burned areas estimations by relating the estimated area with burned area perimeters measured on the ground by Global Positioning System (GPS). In addition, the κ statistic allows us to identify both the optimal spectral index and the optimal algorithms’ parameters. In this work, an accurate estimation (κ > 0.8) of areas burned by forest fires in Mediterranean countries is achieved, in particular if the BAIM index is used. The accuracy of these estimates is compared with the accuracy obtained by using the reference method by a McNemar’s test. Results show that our image mining based method allows a higher accuracy (the average increase of κ equals to 16%) than the reference method. We conclude that this method adequately maps burned areas, and that it may help management agencies to better understand of landscape-scale burn patterns.  相似文献   

Water balances and evapotranspiration in water- and dry-seeded rice systems     

Bruce Linquist  Richard Snyder  Frank Anderson  Luis Espino  Guglielmo Inglese  Serena Marras  Ruben Moratiel  Randall Mutters  Placido Nicolosi  Honza Rejmanek  Alfonso Russo  Tom Shapland  Zhenwei Song  Atef Swelam  Gwen Tindula  Jim Hill 《Irrigation Science》2015,33(5):375-385

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