Bacteria and the evolution of honest signals. The case of ornamental throat feathers in spotless starlings

1. Mechanisms guaranteeing reliability of messages are essential in understanding the underlying information and evolution of signals. Micro-organisms may degrade signalling traits and therefore influence the transmitted information and evolution of these characters. The role of micro-organisms in animal signalling has, however, rarely been investigated. 2. Here, we explore a possible role for feather-degrading bacteria driving the design of ornamental throat feathers in male spotless starlings (Sturnus unicolor). We estimated length, bacterial load, degradation status and susceptibility to degradation by keratinolytic bacteria in those feathers, compared with non-ornamental adjacent feathers in males, as well as to throat feathers in females. In addition, the volume of the uropygial gland and its secretion was measured and the secretion extracted. We also experimentally evaluated the capacity of each secretion to inhibit growth of a keratinolytic bacterium. 3. The apical part of male ornamental throat feathers harboured more bacteria and degraded more quickly than the basal part; these patterns were not detected in female throat feathers or in non-ornamental male feathers. Moreover, degradation status of male and female throat feathers did not differ, but was positively associated with feather bacterial density. Finally, the size of the uropygial gland in both males and females predicted volume and the inhibitory capacity of secretion against feather-degrading bacteria. Only in males was uropygial gland size negatively associated with the level of feather degradation. 4. All results indicate differential susceptibility of different parts of throat feathers to keratinolytic bacterial attack, which supports the possibility that throat feathers in starlings reflect individual ability to combat feather-degrading bacteria honestly. This is further supported by the relationship detected between antimicrobial properties of uropygial secretion and the level of feather degradation. 5. Our results suggest that selection pressures exerted by feather-degrading bacteria on hosts may promote evolution of particular morphologies of secondary sexual traits with different susceptibility to bacterial degradation that reliably inform of their bacterial load. Those results will help to understand the evolution of ornamental signals.This work was financed by Spanish Ministerio de Ciencia e Innovaci on, European funds (FEDER) (CGL2010-19233-C03-01, CGL2013-48193-C3-1-P). MRR and DMG received a postdoc from the program “JAE-Doc”, GT from the “Juan de la Cierva”, and CRC had a predoctoral fellowship, all from the Spanish Government.Peer reviewe

Nest Material Shapes Eggs Bacterial Environment

Selective pressures imposed by pathogenic microorganisms to embryos have selected in hosts for a battery of antimicrobial lines of defenses that includes physical and chemical barriers. Due to the antimicrobial properties of volatile compounds of green plants and of chemicals of feather degrading bacteria, the use of aromatic plants and feathers for nest building has been suggested as one of these barriers. However, experimental evidence suggesting such effects is scarce in the literature. During two consecutive years, we explored experimentally the effects of these nest materials on loads of different groups of bacteria (mesophilic bacteria, Enterobacteriaceae, Staphylococcus and Enterococcus) of eggshells in nests of spotless starlings (Sturnus unicolor) at the beginning and at the end of the incubation period. This was also explored in artificial nests without incubation activity. We also experimentally increased bacterial density of eggs in natural and artificial nests and explored the effects of nest lining treatments on eggshell bacterial load. Support for the hypothetical antimicrobial function of nest materials was mainly detected for the year and location with larger average values of eggshell bacterial density. The beneficial effects of feathers and plants were more easily detected in artificial nests with no incubation activity, suggesting an active role of incubation against bacterial colonization of eggshells. Pigmented and unpigmented feathers reduced eggshell bacterial load in starling nests and artificial nest boxes. Results from artificial nests allowed us to discuss and discard alternative scenarios explaining the detected association, particularly those related to the possible sexual role of feathers and aromatic plants in starling nests. All these results considered together confirm the antimicrobial functionality mainly of feathers but also of plants used as nest materials, and highlight the importance of temporally and geographically environmental variation associated with risk of bacterial proliferation determining the strength of such effects. Because of costs associated to nest building, birds should adjust nest building effort to expected bacterial environments during incubation, a prediction that should be further explored.This work was financed by Spanish Ministerio de Ciencia e Innovación, European funds (FEDER) (CGL2010-19233-C03-01, CGL2010-19233-C03-03, CGL2013-48193-C3-1-P, CGL2013-48193-C3-3-P). MRR and DMG received a postdoc from the programmes “JAE-Doc” and CRC had a predoctoral grant from the Spanish Government. GT was supported by Juan de la Cierva programme (Spain) and by Secretaría de Educación Superior, Ciencia, Tecnología e Innovación del Ecuador (SENESCYT) through a Prometeo research grant.Peer reviewe

Intraspecific avian brood parasites avoid host nests infested by ectoparasites

Intraspecific brood parasitism is widespread among birds and provides clues for elucidating the evolutionary origin of interspecific brood parasitism. Studies suggest that brood parasitism does not occur at random, but that parasitic females select nests with advantages such as higher physical stability, reduced predation risk, or lower ectoparasite infestations. However, this evidence is sparse and mainly correlative. By experimentally increasing the abundance of Carnus hemapterus (a common, generalist and widespread ectoparasitic nest fly of a multitude of bird species) in half of the nests, we show that parasitic Spotless Starlings (Sturnus unicolor) avoid conspecific nests infested by ectoparasites. Since Carnus ectoparasites impinge costs on their avian nestling hosts, this avoidance response would be adaptive for parasitic Starlings. Further, we suggest a mechanism by which parasitic females may assess the level of ectoparasite infestation to select host nests accordingly: by using parasite cues such as faeces and blood remains. Additionally, these cues may be used by parasitic females for synchronization with the reproductive cycle of host females because ectoparasite cues also indicate that incubation has already commenced. Whatever the functionality, the mechanism suggested here may be employed by intra- and interspecific brood parasites, so it might represent a widespread strategy in nature.Financial support was provided by the Spanish Ministerio de Economía y Competitividad and FEDER (CGL2013- 48193-C3-1-P), the JAE programme to D. M. G. and M. R. R., and the Ramo´n y Cajal programme (Spain) and the Secretarı´a de Educacio ´n Superior, Ciencia, Tecnologı´a e Innovacio´n del Ecuador (SENESCYT) through a Prometeo research grant to G. TPeer reviewe

Gut Microbiota of Great Spotted Cuckoo Nestlings is a Mixture of Those of Their Foster Magpie Siblings and of Cuckoo Adults

Diet and host genetic or evolutionary history are considered the two main factors determining gut microbiota of animals, although studies are scarce in natural populations. The system of great spotted cuckoos (Clamator glandarius) parasitizing magpies (Pica pica) is ideal to study both effects since magpie adults feed cuckoo and magpie nestlings with the same diet and, consequently, differences in gut microbiota of nestlings of these two species will mainly reflect the importance of genetic components. Moreover, the diet of adults and of nestling cuckoos drastically differ from each other and, thus, differences and similarities in their microbiotas would respectively reflect the effect of environmental and genetic factors. We used next-generation sequencing technologies to analyze the gut microbiota of cuckoo adults and nestlings and of magpie nestlings. The highest -diversity estimates appeared in nestling cuckoos and the lowest in nestling magpies. Moreover, despite the greatest differences in the microbiome composition of magpies and cuckoos of both ages, cuckoo nestlings harbored a mixture of the Operational Taxonomic Units (OTUs) present in adult cuckoos and nestling magpies. We identified the bacterial taxa responsible for such results. These results suggest important phylogenetic components determining gut microbiome of nestlings, and that diet might be responsible for similarities between gut microbiome of cuckoo and magpie nestlings that allow cuckoos to digest food provided by magpie adults.This work was supported by the Ministerio de Ciencia, Innovacion y Universidades and European (FEDER) funds (CGL2017-83103-P)

Identification of 34 novel mutations in propionic acidemia: Functional characterization of missense variants and phenotype associations

Propionic acidemia (PA) is caused by mutations in the PCCA and PCCB genes, encoding α and β subunits, respectively, of the mitochondrial enzyme propionyl-CoA carboxylase (PCC). Up to date, >200 pathogenic mutations have been identified, mostly missense defects. Genetic analysis in PA patients referred to the laboratory for the past 15 years identified 20 novel variants in the PCCA gene and 14 in the PCCB gene. 21 missense variants were predicted as probably disease-causing by different bioinformatics algorithms. Structural analysis in the available 3D model of the PCC enzyme indicated potential instability for most of them. Functional analysis in a eukaryotic system confirmed the pathogenic effect for the missense variants and for one amino acid deletion, as they all exhibited reduced or null PCC activity and protein levels compared to wild-type constructs. PCCB variants p.E168del, p.Q58P and p.I460T resulted in medium-high protein levels and no activity. Variants p.R230C and p.C712S in PCCA, and p.G188A, p.R272W and p.H534R in PCCB retained both partial PCC activity and medium-high protein levels. Available patients-derived fibroblasts carriers of some of these mutations were grown at 28 °C or 37 °C and a slight increase in PCC activity or protein could be detected in some cases at the folding-permissive conditions. Examination of available clinical data showed correlation of the results of the functional analysis with disease severity for most mutations, with some notable exceptions, confirming the notion that the final phenotypic outcome in PA is not easily predictedWe thank the following physicians/clinicians for sending samples for genetic analysis: Dr. Wilson (Auckland, New Zealand), Dr. Parini (Rome, Italy), Dr. Vilaseca (Barcelona, Spain), Dr. Gockay (Istanbul, Turkey), Dr. Al Sannaa (Saudi Arabia), Dr. Pedrón (Madrid, Spain), Dr. Savvapoulou (Tesalonica, Greece), Dr. Martínez-Pardo (Madrid, Spain), Dr. Lama (Madrid, Spain), Dr. Lemes (Montevideo, Uruguay), Dr. Van Calcar (Madison, USA), Dr. Pintos (Badalona, Spain), Dr. Laszlo (Szeged, Hungary), Dr. Kuijtmans (Nijmegen, The Netherlands), Dr. Schatz (München, Germany), Dr. EL Khateeb (Jordan), Dr. de las Heras (Baracaldo, Spain), Dr. Miñana (Buenos Aires, Argentina). The technical assistance of A. Sánchez is gratefully acknowledged. This work was supported by Spanish Ministry of Economy and Competitiveness and European Regional Development Fund (grant number SAF2016-76004-R). Centro de Biología Molecular Severo Ochoa receives an institutional grant from Fundación Ramón Arece

The microbiome of the uropygial secretion in hoopoes is shaped along the nesting phase

Microbial symbiont acquisition by hosts may determine the effectiveness of the mutualistic relationships. A mix of vertical and horizontal transmission may be advantageous for hosts by allowing plastic changes of microbial communities depending on environmental conditions. Plasticity is well known for gut microbiota but is poorly understood for other symbionts of wild animals. We here explore the importance of environmental conditions experienced by nestling hoopoes (Upupa epops) during the late nesting phase determining microbiota in their uropygial gland. In cross-fostering experiments of 8 days old nestlings, “sibling-sibling” and “mother-offspring” comparisons were used to explore whether the bacterial community naturally established in the uropygial gland of nestlings could change depending on experimental environmental conditions (i.e., new nest environment). We found that the final microbiome of nestlings was mainly explained by nest of origin. Moreover, cross-fostered nestlings were more similar to their siblings and mothers than to their stepsiblings and stepmothers. We also detected a significant effect of nest of rearing, suggesting that nestling hoopoes acquire most bacterial symbionts during the first days of life but that the microbiome is dynamic and can be modified along the nestling period depending on environmental conditions. Estimated effects of nest of rearing, but also most of those of nest of origin are associated to environmental characteristics of nests, which are extended phenotypes of parents. Thus, natural selection may favor the acquisition of appropriated microbial symbionts for particular environmental conditions found in nests.Support by funding was provided by Spanish Ministerio de Economía y Competitividad, European funds (FEDER) (CGL2013-48193-C3-1-P, CGL2013-48193-C3-2-P), and Junta de Andalucía (P09-RNM-4557). AM-G had a predoctoral grant from the Junta de Andalucía (P09-RNM-4557).Peer reviewe

Experiencias para desarrollar competencias de emprendimiento en la formación universitaria

Es indudable que la Educación Superior puede generar impacto en el desarrollo económico de un país y una de las formas en las cuales es posible actuar, es en el fomento e impulso al emprendimiento como actividad clave.  Este proceso formativo puede ser desarrollado a través de las funciones sustantivas de la universidad: Docencia, Investigación e Innovación y Vinculación con la Sociedad. Para ello el presente trabajo desde la perspectiva de la acción docente, tiene como objetivo dar a conocer las experiencias de emprendimiento de los estudiantes de la Carrera de Administración de Empresas de la Universidad Católica de Cuenca, quienes decidieron enfrentar el reto de emprender, poniendo en práctica los conocimientos adquiridos durante su proceso de formación, bajo la dirección de docentes gestores de emprendimiento. En este estudio cualitativo se aborda las competencias desde el enfoque del pensamiento complejo, su alcance es descriptivo, utiliza la técnica de la observación participante para extraer resultados, los mismos que reflejan la aplicación de importantes competencias inherentes al emprendimiento en las actividades los estudiantes de la Carrera en estudio, concluyendo que es posible desarrollar estas competencias mediante actividades de estudio curriculares y extracurriculares

Conocimiento del Anticonceptivo de Emergencia o “Píldora del Día Siguiente”, en Estudiantes Universirarios

Introducción. Un embarazo no deseado se ha convertido en un grave problema de salud pública, el cual está estrechamente relacionado con una deficiente educación sexual, adopción de conductas sexuales de riesgo y poco conocimiento de los métodos anticonceptivos de emergencia. Objetivo. Determinar el nivel de conocimiento que tienen los jóvenes universitarios sobre el uso de la píldora del día siguiente, mediante la aplicación de un cuestionario, con la finalidad de tener un referente actual del fenómeno. Metodología. Estudio transversal, descriptivo, se trabajó con 308 estudiantes de la Facultad de Derecho y Química, de una universidad pública. Muestreo fue por conveniencia. Se consideraron alumnos cuyas parejas sexuales fueran del sexo contrario o bien, ambos y que tuvieran vida sexual activa, de quienes se obtuvo consentimiento verbal. Análisis de datos mediante estadística descriptiva usando el programa EXCEL y SPSS. Resultados. Se tuvieron 210 cuestionarios de la Facultad de Derecho y 98 de Química. 58% de los jóvenes fueron mujeres. Del total de participantes, 264 respondieron a la pregunta de si han usado alguna vez la pastilla. De estos, 77.3% sí han recurrido a ella desde que iniciaron su vida sexual. Con respecto al nivel de conocimientos, los alumnos de Derecho, tuvieron 30% de conocimiento regular y malo y en Química 30.6%. Con respecto al género, 31% de los datos erróneos, fueron de las mujeres y 40% de los varones. Conclusiones. Un alto porcentaje de alumnos han usado este medicamento, por lo que es necesario reforzar los conocimientos sobre su correcto uso.   Introduction. Unwanted pregnancies have become a serious public health problem, which is closely related to poor sexual education, adoption of risky sexual behaviors and little knowledge of emergency contraceptive methods. Objective. To determine the level of knowledge that young university students have about the use of the morning-after pill, through the application of a questionnaire, in order to have a current frame of reference about this phenomenon. Methodology. Cross-sectional, descriptive study. We worked with 308 students from the College of Law and Chemistry of a public university. We used convenience sampling. We considered students whose sexual partners were of the opposite or same sex, and who were sexually active, and their verbal consent was obtained. Data analysis was conducted through descriptive statistics using EXCEL and the SPSS program. Results. 210 questionnaires were obtained from the College of Law and 98 from Chemistry. 58% of the participants were women. Of the total participants, 264 responded to the question of whether they had ever used the pill. Of these, 77.3% indicated they have resorted to it since they became sexually active. Regarding the level of knowledge, 30% of Law students had average and poor knowledge, and Chemistry students 30.6%. Regarding gender, 31% of those with no knowledge of the pill were women and 40% were men. Conclusion. A high percentage of students have used this medication, so it is necessary to reinforce knowledge about its correct use

The Hoopoe's Uropygial Gland Hosts a Bacterial Community Influenced by the Living Conditions of the Bird

Molecular methods have revealed that symbiotic systems involving bacteria are mostly based on whole bacterial communities. Bacterial diversity in hoopoe uropygial gland secretion is known to be mainly composed of certain strains of enterococci, but this conclusion is based solely on culture-dependent techniques. This study, by using culture-independent techniques (based on the 16S rDNA and the ribosomal intergenic spacer region) shows that the bacterial community in the uropygial gland secretion is more complex than previously thought and its composition is affected by the living conditions of the bird. Besides the known enterococci, the uropygial gland hosts other facultative anaerobic species and several obligated anaerobic species (mostly clostridia). The bacterial assemblage of this community was largely invariable among study individuals, although differences were detected between captive and wild female hoopoes, with some strains showing significantly higher prevalence in wild birds. These results alter previous views on the hoopoe-bacteria symbiosis and open a new window to further explore this system, delving into the possible sources of symbiotic bacteria (e.g. nest environments, digestive tract, winter quarters) or the possible functions of different bacterial groups in different contexts of parasitism or predation of their hoopoe host.This work was supported by the Ministerio de Ciencia y Tecnología (projects CGL2005-06975/BOSFEDER; CGL2007-61251/BOSFEDER), the Ministerio de Ciencia e Innovación (projects CGL2009-14006/BOSFEDER; CGL2010-19233-C03-01/BOSFEDER; CGL2010-19233-C03-03/BOSFEDER), the Ministerio de Economía y Competitividad (projects CGL2013-48193-C3-1-P/BOSFEDER; CGL2013-48193-C3-2-P/BOSFEDER), and the Junta de Andalucía (RNM 345, P09-RNM-4557). SMRR received a grant from the Ministerio de Ciencia e Innovación (FPI program, BES-2011-047677)