Juan Manuel Peralta-Sánchez

University of Seville · Zoology

Microbes live within complex communities of interacting populations, either free-living in waters and soils or symbionts of animals and plants. Their interactions include the production of antimicrobial peptides (bacteriocins) to antagonize competitors, and these producers must carry their own immunity gene for self-protection. Whether other coexis...

Traditional spontaneously fermented foods are well known for their sensory and safety properties, which is mainly due to their indigenous microflora. Within this group of food, Mediterranean dry-cured sausages stand out as a significant source of lactic-acid bacterial strains (LAB) with biotechnological properties, such as their antimicrobial activ...

Obligate brood parasites lay their eggs in nests of other species, with host parents bearing the cost of raising their offspring. These costs imposed on hosts select for the evolution of host defenses against parasitism at all stages of the reproductive cycle. The most effective defense is egg rejection at early stages of the breeding cycle, with l...

Recent field data suggest that migratory gulls disperse many rice field weeds by gut passage (endozoochory), most of which are dry fruited and widely assumed to have no long-distance dispersal mechanisms, except via human activity. We investigated this mechanism with a feeding experiment, in which seeds of five common rice field weeds (in order of...

The global demand for fish products is continuously increasing as the population grows, and aquaculture plays an important role in supplying this demand. However, industrial antibiotic misuse has contributed to the spread of antimicrobial resistance among pathogenic bacteria, therefore, several antibiotic alternatives have been proposed. In this st...

A way of untangling the trade-off between investment in current offspring versus self-maintenance and future reproductive success is to determine how both parents allocate food between themselves and their offspring according to food availability. The hoopoe, Upupa epops, is an excellent model to test hypotheses about these decisions, since it is a...

This study analyzes the potential use of an Allium-derived compound, propyl propane thiosulfonate (PTSO), as a functional feed additive in aquaculture. Gilthead seabream (Sparus aurata) juveniles had their diet supplemented with this Allium-derived compound (150 mg/kg of PTSO) and were compared with control fish. The effects of this organosulfur co...

In their struggle for life, bacteria frequently produce antagonistic substances against competitors. Antimicrobial peptides produced by bacteria (known as bacteriocins) are active against other bacteria, but harmless to their producer due to an associated immunity gene that prevents self-inhibition. However, knowledge of cross-resistance between di...

The signalling hypothesis suggests that avian eggshell coloration is a sexually selected female signal advertising her quality to its male partner, thereby stimulating his provisioning rate. This hypothesis has been tested for structural eggshell pigments, but not for cosmetic colorations, such as that produced by the uropygial secretion on eggshel...

Migratory birds may have a vital role in the spread of antimicrobial resistance across habitats and regions, but empirical data remain scarce. We investigated differences in the gut microbiome composition and the abundance of antibiotic resistance genes (ARGs) in faeces from four migratory waterbirds wintering in South-West Spain that differ in the...

Parasites exert a strong selection pressure on their hosts as manifested in behavioural antiparasite traits to reduce negative impacts on fitness. The numerous nest‐dwelling ecto‐parasites residing in avian nests make altricial birds excellent model‐systems for investigating the relationship between parasites and their hosts. Here, we experimentall...

Antimicrobial resistance (AMR) has risen as a global threat for human health. One of the leading factors for this emergence has been the massive use of antibiotics growth-promoter (AGPs) in livestock, enhancing the spread of AMR among human pathogenic bacteria. Thus, several alternatives such as probiotics, prebiotics, or phytobiotics have been pro...

Phytobiotics (bioactive compounds extracted from plants) are one of the explored alternatives to antibiotics in poultry and livestock due to their antimicrobial activity and its positive effects on gut microbiota and productive properties. In this study, we supplemented a product based on garlic and onion compounds in the diet to laying hens at the...

Nest bacterial environment influences avian reproduction directly because it might include pathogenic- or antibiotic-producing bacteria or indirectly because predators or ectoparasites can use volatile compounds from nest bacterial metabolism to detect nests of their avian hosts. Hoopoes (Upupa epops) do not build nests. They rather reuse holes or...

BACKGROUND Differences in the composition of the intestinal microbiota and energetic metabolism between lean and obese populations have been described. Legume consumption has been reported to modulate intestinal microbiota composition. However, to the best of our knowledge, no information can be found in the literature on the effects of consumption...

Gut microbiota are essential for host health and survival, but we are still far from understanding the processes involved in shaping their composition and evolution. Controlled experimental work under lab conditions as well as human studies pointed at environmental factors (i.e., diet) as the main determinant of the microbiota with little evidence...

Self-recognition in animals is demonstrated when individuals pass the mark test. Formerly, it was thought that self-recognition was restricted to humans, great apes, and certain mammals with large brains and highly evolved social cognition. However, 1 study showed that 2 out of 5 magpies (Pica pica) passed the mark test, suggesting that magpies hav...

Which sex has a more determinant role in reproductive performance? This is a long standing question in evolutionary ecology. Theory predicts and several pieces of evidence have indicated that females are more determinant than males. However, a direct test of this hypothesis has never been made. Here we perform such a direct test by using an alterna...

Antimicrobial resistance (AMR) is one of the most serious threats for human health in the near future. Livestock has played an important role in the appearance of antibiotic-resistant bacteria, intestinal dysbiosis in farming animals, or the spread of AMR among pathogenic bacteria of human concern. The development of alternatives like probiotics is...

The uropygial gland of hoopoe nestlings and nesting females hosts bacterial symbionts that cause changes in the characteristics of its secretion, including an increase of its antimicrobial activity. These changes occur only in nesting individuals during the breeding season, possibly associated with the high infection risk experienced during the sta...

While direct detrimental effects of parasites on hosts are relatively well documented, other more subtle but potentially important effects of parasitism are yet unexplored. Biological activity of ectoparasites, apart from skin injuries and blood-feeding, often results in blood remains, or parasite faeces that accumulate and modify the host environm...

Bacterial communities within avian nests are considered an important determinant of egg viability, potentially selecting for traits that confer embryos with protection against trans-shell infection. A high bacterial density on the eggshell increases hatching failure, whether this effect could be due to changes in bacterial community or just a gener...

Our growing awareness of the microbial world’s importance and diversity contrasts starkly with our limited understanding of its fundamental structure. Despite recent advances in DNA sequencing, a lack of standardized protocols and common analytical frameworks impedes comparisons among studies, hindering the development of global inferences about mi...

The study of associations between symbiotic bacterial communities of hosts and those of surrounding environments would help to understand how bacterial assemblages are acquired, and how they are transmitted from one to another location (i.e. symbiotic bacteria acquisition by hosts). Hoopoes (Upupa epops) smear their eggshells with uropygial secreti...

Study of the bacterial load of the nest materials used in the experiment. Approximately the same amount of experimental (mean(SE) = 37.75(2.85) g) and control (mean(SE) = 37.75(2.85) g) material were diluted in 1mL of 0.2M pH7.2 phosphatase saline buffer. Bacterial load was estimated as number of Colony Forming Units (CFUs) in TSA media and serial...

Study of the antimicrobial activity of the experimental material used (crushed olive stones). Antimicrobial activity of experimental nest material was tested against the following bacterial strains that included known pathogenic and keratinolytic bacteria: Proteus sp., Escherichia coli, Mycobacterium sp., Bacillus licheniformis D13, Staphylococcus...

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 oth...

How microbial symbionts are established and maintain on their hosts is a leading question with important consequences for the understanding of the evolution and functioning of mutualistic relationships. The acquisition by hosts of mutualistic microbial symbionts can be considered as colonization processes of environments (i.e., host) by symbionts....

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-indepen...

Exploring factors guiding interactions of bacterial communities with animals has become of primary importance for ecologists and evolutionary biologists during the last years because of their likely central role in the evolution of animal life history traits. We explored the association between laying date and eggshell bacterial load (mesophilic ba...

Exploring coevolutionary processes between microorganisms and their hosts is a new imperative for life sciences. If bacteria protect hosts against pathogens, mechanisms facilitating the intergenerational transmission of such bacteria will be strongly selected by evolution. By disentangling the diversity of bacterial strains from the uropygium of ho...

Uropygial gland secretions are used as cosmetics by some species of birds to color and enhance properties of feathers and teguments, which may signal individual quality. Uropygial secretions also reach eggshells during incubation and, therefore, may influence the coloration of birds' eggs, a trait that has attracted the attention of evolutionary bi...

Infectious diseases and parasitism are major environmental forces decreasing fitness, and thus individual strategies aimed at preventing pathogen infections, either in an individual or their offspring, should be favoured by natural selection. The mineral fraction and some organic compounds in the shells of bird eggs are considered physical and chem...

Animals live in a bacterial world, and detecting and exploring adaptations favouring mutualistic relationships with antibiotic‐producing bacteria as a strategy to fight pathogens are of prime importance for evolutionary ecologists. Uropygial secretion of European hoopoes ( Upupa epops, Linnaeus) contains antimicrobials from mutualistic bacteria tha...

Some animals are capable of recognizing themselves in a mirror, which is considered to be demonstrated by passing the mark test. Mirror self-recognition capacity has been found in just a few mammals having very large brains and only in one bird, the magpie (Pica pica). The results obtained in magpies have enormous biological and cognitive implicati...

The use of feathers to line bird's nests has traditionally been interpreted as having a thermoregulatory function. Feather-degrading bacteria growing on feathers lining nests may have antimicrobial properties, which may provide an additional benefit to lining nests with feathers. We test the hypothesis that the production of antimicrobial substance...

High-throughput DNA sequencing technologies, coupled with advanced bioinformatics tools, have enabled rapid advances in microbial ecology and our understanding of the human microbiome. QIIME (Quantitative Insights Into Microbial Ecology) is an open-source bioinformatics software package designed for microbial community analysis based on DNA sequenc...

Selection pressures due to parasitism play an important role in driving the evolution of life history traits of birds in general and of behaviour at the nest in particular. Eggshell bacterial load has been shown to predict hatching failure (i.e. the probability of embryo infection) but the relationships between the bacterial environment of the nest...

Symbiotic microorganisms may be directly transferred from parents to offspring or acquired from a particular environment that animals may be able to select. If benefits for hosts vary among microbial strains, natural selection may favour hosts holding the most beneficial one. Enterococci symbionts living in the hoopoe (Upupa epops) uropygial gland...

Potentially, pathogenic bacteria are one of the main infective agents against which a battery of chemical and physical barriers has evolved in animals. Among these are the secretions by the exocrine uropygial gland in birds. The antimicrobial properties of uropygial secretions may prevent colonization and growth of microorganisms on feathers, skin...

1. Predators often prey on individuals that are sick or otherwise weakened. Although previous studies have shown higher abundance of parasites in prey, whether prey have elevated loads of micro-organisms remains to be determined. 2. We quantified the abundance of bacteria and fungi on feathers of woodpigeons Columba palumbus L., jays Garrulus gland...

Parasite-mediated selection may affect the evolution of cognitive abilities because parasites may influence development of the brain, but also learning capacity. Here, we tested some predictions of this hypothesis by analyzing the relationship between complex behaviours (feeding innovations (as a measure of behavioural flexibility) and ability to d...

Fitness benefits associated with the development of a costly immune system would include not only self-protection against pathogenic microorganisms but also protection of host offspring if it reduces the probability and the rate of vertical transmission of microorganisms. This possibility predicts a negative relationship between probabilities of ve...

Factors related to bacterial environment of nests are of primary interest for understanding the causes of embryo infection and the evolution of antimicrobial defensive traits in birds. Nest visitors such as parasites could act as vectors for bacteria and/or affect the hygienic conditions of nests and hence influence the nest bacterial environ-ment....

Populations of migratory birds differ in their direction of migration with neighbouring populations often migrating in divergent directions separated by migratory divides. A total of 26% of 103 passerine bird species in Europe had migratory divides that were located disproportionately often along a longitudinal gradient in Central Europe, consisten...

There is increasing interest in noninvasive DNA sampling techniques. In birds, there are several methods proposed for sampling DNA, and of these, the use of eggshell swabbing is potentially applicable to a wide range of species. We estimated the effectiveness of this method in the wild by sampling the eggs of 23 bird species. Sampling of eggs was p...

Many bird species use feathers as lining material, and its functionality has traditionally been linked to nest insulation. However, nest lining feathers may also influence nest detection by predators, differentially affect reproductive investment of mates in a post-mating sexual selection process, and affect the bacterial community of the nest envi...

1. The use of feathers as nest lining material has traditionally been explained by the thermoregulatory properties of feathers. Feather nest lining could additionally affect nest detectability by predators, or play a role in a sexually selected context. Furthermore, feather nest lining harbours microorganisms that may influence environmental condit...

Theory strongly suggests that beneficial symbiotic bacteria could be common within birds. Our argument is based on the existence of within-host competition for resources between bacteria (i.e. bacterial interference), and on the differential effect that host fitness (i.e., reproductive success and probability of survival) has on fitness of differe...

Animals frequently use metabolites produced by symbiotic bacteria as agents against pathogens and parasites. Secretions from the preen gland of birds are used for this purpose, although its chemicals apparently are produced by the birds themselves. European hoopoes Upupa epops and green woodhoopoes Phoeniculus purpureus harbour symbiotic bacteria i...

Microbial communities present on eggshell surfaces of wild birds are weakly studied, especially their influence on embryo infection and, thus, egg viability. Bacterial density of wild bird eggshells is very low, and most DNA extraction protocols are frequently unsuccessful. We have efficiently adapted a chelex-based DNA isolation method for 16S rib...

The uropygial glands of birds serve multiple functions, and there is great interspecific variability in the composition and properties of their secretions. A special case is the secretion in the hoopoes Upupa epops, and green woodhoopoes Phoeniculus purpureus, which, contrary to the commonly white and odourless secretions, are dark with pungent odo...

1. It has been recently showed that one bacterial strain isolated from the uropygial gland of a nestling hoopoe Upupa epops produced antimicrobial peptides active against a broad spectrum of pathogenic bacteria. These bacteria might thus mediate antimicrobial properties of the uropygial secretions as a consequence of the symbiotic association with...