Standardization of a Sex-Sorting Protocol for Stallion Spermatozoa by Means of Absolute RT-qPCR.

Sperm sexing is a technology that can generate great economic benefits in the animal production sector. Techniques such as sex-sorting promise over 90% accuracy in sperm sexing. However, for the correct standardization of the technique, some laboratory methodologies are required. The present manuscript describes in detail a standardized equine sperm sex-sorting protocol using an absolute qPCR-based methodology. Furthermore, the results of absolute qPCR were implemented and validated by generating equine/bovine heterologous embryos by intracytoplasmic sperm injection (ICSI) of presumably sexed equine spermatozoa into bovine oocytes using a piezoelectric system (Piezo-ICSI). Our results indicated that equine sex-sorting spermatozoa had a 97% and 94% certainty for X and Y sperm, respectively, while presumptive female and male equine/bovine hybrid embryos, generated by Piezo-ICSI, had an accuracy of 92% with respect to the desired sex. Therefore, it is concluded that the presented methodology is a reliable, cost-effective, and relatively simple option for standardizing sex-sorting of equine spermatozoa. This is supported by the results of the correct sexing of Piezo-ICSI heterologous embryos generated with the sexed spermatozoa, validating the correct sexing and viability of these gametes.

Quail eggs in artificial nests change their coloration when exposed to ambient conditions: implication for studies on nest predation.

Quail eggs have been widely used in field experiments, mainly to study factors associated with the risk of nest predation. Some shortcomings of using quail eggs in this type of study have been previously addressed (e.g., these eggs might be too big for some predators of eggs of small birds). Here, we show experimental evidence of another shortcoming of the use of these eggs in field experiments. Quail eggs exposed to sunlight rapidly faded in colour after three days, both in the visible and UV spectra, and this change was related to the amount of solar radiation received. This caused changes in the camouflage of the eggs, which may be perceived by predators with different visual systems (dichromatic, trichromatic, and tetrachromatic (for both violet- and UV-sensitive species)). Therefore, the results of field studies of nest predation using quail eggs might be questioned in those cases in which the camouflage has been altered due to the rapid changes in coloration, as this can affect the resulting predation rates. We recommend that researchers planning to use quail eggs should perform a prospective assessment of changes in coloration of eggs exposed to environmental conditions in the nest sites used by the target species.

Efecto antimicrobiano sobre Streptococcus mutans de sistema adhesivo con nanopartículas de óxido de zinc y cobre / Antimicrobial effect against Streptococcus mutans of an adhesive system with copper and zinc oxide nanoparticles

Objetivo: Determinar las propiedades antimicrobianas de la incorporación de nanopartículas de óxido de zinc y cobre en un adhesivo de grabado y lavado total sobre Streptococcus mutans en pacientes con restauraciones de resina compuesta confeccionadas con adhesivo cargado. Métodos: Este estudio clínico randomizado, participaron 25 pacientes, de ambos sexos, pertenecientes al posgrado de Ortodoncia de la Facultad de Odontología de la Universidad de Chile, en los cuales se confirmó presencia de Streptococcus mutans en saliva. Se confeccionaron restauraciones de resina compuesta oclusales, en premolares superiores con indicación de exodoncia por el tratamiento de ortodoncia, con adhesivo cargado (cuya composición es 5 / 0.2 por ciento ZnO y Cu respectivamente) y control (sin presencia de nanopartículas en su composición), según el listado de aleatorización. Se tomaron muestras microbiológicas en tres tiempos con la Técnica de la cubeta (antes, 1 semana y 4 semanas posterior a la confección de las restauraciones). Se obtuvieron, aislaron e identificaron colonias de Streptococcus mutans a partir de las muestras obtenidas. Los datos fueron analizados por el test de Mann Whittney. Resultados: El promedio del recuento de UFC (unidades formadoras de colonias) de Streptococcus mutans en el grupo experimental fue mayor posterior a la confección de las restauraciones de resina compuesta.Los resultados de la identificación molecular por PCR demuestran la presencia de Streptococcus mutans en 20 de 25 muestras. Conclusiones: No existen diferencias en el recuento de Streptococcus mutans antes y después de la aplicación del adhesivo sobre las restauraciones de resina compuesta(AU)

Objective: Determine the antimicrobial properties of the incorporation of copper and zinc oxide nanoparticles into a total rinse and etch adhesive against Streptococcus mutans in patients with composite resin restorations made with loaded adhesive. Methods: A randomized clinical study was conducted of 25 patients of both sexes from the orthodontics graduate course taught at the Dental School of the University of Chile, in whom the presence of Streptococcus mutans was confirmed in saliva. Occlusal composite resin restorations were performed in upper premolars with exodontia indicated as part of the orthodontic treatment, using loaded adhesive (composition 5 / 0.2 percent ZnO and Cu, respectively) and control (without nanoparticles in its composition), according to the randomization list. Microbiological samples were taken at three moments applying the tray technique (before, 1 week after and 4 weeks after the restorations). Streptococcus mutans were obtained, isolated and identified from the samples taken. Data analysis was based on the Mann-Whitney test. Results: Mean Streptococcus mutans CFU count in the experimental group was higher after the composite resin restorations were made. Results of PCR molecular identification show the presence of Streptococcus mutans in 20 of 25 samples. Conclusions: No differences were found in the Streptococcus mutans count before and after application of the adhesive over the composite resin restorations(AU)

Association of insularity and body condition to cloacal bacteria prevalence in a small shorebird.

Do islands harbour less diverse disease communities than mainland? The island biogeography theory predicts more diverse communities on mainland than on islands due to more niches, more diverse habitats and availability of greater range of hosts. We compared bacteria prevalences of Campylobacter, Chlamydia and Salmonella in cloacal samples of a small shorebird, the Kentish plover (Charadrius alexandrinus) between two island populations of Macaronesia and two mainland locations in the Iberian Peninsula. Bacteria were found in all populations but, contrary to the expectations, prevalences did not differ between islands and mainland. Females had higher prevalences than males for Salmonella and when three bacteria genera were pooled together. Bacteria infection was unrelated to bird's body condition but females from mainland were heavier than males and birds from mainland were heavier than those from islands. Abiotic variables consistent throughout breeding sites, like high salinity that is known to inhibit bacteria growth, could explain the lack of differences in the bacteria prevalence between areas. We argue about the possible drivers and implications of sex differences in bacteria prevalence in Kentish plovers.

Does the use of nest materials in a ground-nesting bird result from a compromise between the risk of egg overheating and camouflage?

Many studies addressing the use of nest materials by animals have focused on only one factor to explain its function. However, the consideration of more than one factor could explain the apparently maladaptive choice of nest materials that make nests conspicuous to predators. We experimentally tested whether there is a trade-off in the use of nest materials between the risks of egg predation versus protection from overheating. We studied the ground-nesting Kentish plover, Charadrius alexandrinus, in southern Spain. We added materials differing in thermal properties and coloration to the nests, thus affecting rates of egg heating, nest temperature and camouflage. Before these manipulations, adults selected materials that were lighter than the microhabitat, probably to buffer the risk of egg overheating. However, the adults did not keep the lightest experimental materials, probably because they reduced camouflage, and this could make the nests even more easily detectable to predators. In all nests, adults removed most of the experimental materials independently of their properties, so that egg camouflage returned to the original situation within a week of the experimental treatments. Although the thermal environment may affect the choice of nest materials by plovers, ambient temperatures were not so high at our study site as to determine the acceptance of the lightest experimental materials.

Intake rates and the functional response in shorebirds (Charadriiformes) eating macro-invertebrates.

As field determinations take much effort, it would be useful to be able to predict easily the coefficients describing the functional response of free-living predators, the function relating food intake rate to the abundance of food organisms in the environment. As a means easily to parameterise an individual-based model of shorebird Charadriiformes populations, we attempted this for shorebirds eating macro-invertebrates. Intake rate is measured as the ash-free dry mass (AFDM) per second of active foraging; i.e. excluding time spent on digestive pauses and other activities, such as preening. The present and previous studies show that the general shape of the functional response in shorebirds eating approximately the same size of prey across the full range of prey density is a decelerating rise to a plateau, thus approximating the Holling type II ('disc equation') formulation. But field studies confirmed that the asymptote was not set by handling time, as assumed by the disc equation, because only about half the foraging time was spent in successfully or unsuccessfully attacking and handling prey, the rest being devoted to searching.A review of 30 functional responses showed that intake rate in free-living shorebirds varied independently of prey density over a wide range, with the asymptote being reached at very low prey densities (<150/m-2). Accordingly, most of the many studies of shorebird intake rate have probably been conducted at or near the asymptote of the functional response, suggesting that equations that predict intake rate should also predict the asymptote.A multivariate analysis of 468 'spot' estimates of intake rates from 26 shorebirds identified ten variables, representing prey and shorebird characteristics, that accounted for 81% of the variance in logarithm-transformed intake rate. But four-variables accounted for almost as much (77.3%), these being bird size, prey size, whether the bird was an oystercatcher Haematopus ostralegus eating mussels Mytilus edulis, or breeding. The four variable equation under-predicted, on average, the observed 30 estimates of the asymptote by 11.6%, but this discrepancy was reduced to 0.2% when two suspect estimates from one early study in the 1960s were removed. The equation therefore predicted the observed asymptote very successfully in 93% of cases. We conclude that the asymptote can be reliably predicted from just four easily measured variables. Indeed, if the birds are not breeding and are not oystercatchers eating mussels, reliable predictions can be obtained using just two variables, bird and prey sizes. A multivariate analysis of 23 estimates of the half-asymptote constant suggested they were smaller when prey were small but greater when the birds were large, especially in oystercatchers. The resulting equation could be used to predict the half-asymptote constant, but its predictive power has yet to be tested. As well as predicting the asymptote of the functional response, the equations will enable research workers engaged in many areas of shorebird ecology and behaviour to estimate intake rate without the need for conventional time-consuming field studies, including species for which it has not yet proved possible to measure intake rate in the field.