Host phylogeny and environment shape the diversity of salamander skin bacterial communities.

The composition and diversity of animal-associated microbial communities are shaped by multiple ecological and evolutionary processes acting at different spatial and temporal scales. Skin microbiomes are thought to be strongly influenced by the environment due to the direct interaction of the host's skin with the external media. As expected, the diversity of amphibian skin microbiomes is shaped by climate and host sampling habitats, whereas phylogenetic effects appear to be weak. However, the relative strength of phylogenetic and environmental effects on salamander skin microbiomes remains poorly understood. Here, we analysed sequence data from 1164 adult salamanders of 44 species to characterise and compare the diversity and composition of skin bacteria. We assessed the relative contribution of climate, host sampling habitat, and host phylogeny to the observed patterns of bacterial diversity. We found that bacterial alpha diversity was mainly associated with host sampling habitat and climate, but that bacterial beta diversity was more strongly associated with host taxonomy and phylogeny. This phylogenetic effect predominantly occurred at intermediate levels of host divergence (0-50 Mya). Our results support the importance of environmental factors shaping the diversity of salamander skin microbiota, but also support host phylogenetic history as a major factor shaping these bacterial communities.

Genomic characterization of antifungal Acinetobacter bacteria isolated from the skin of the frogs Agalychnis callidryas and Craugastor fitzingeri.

Chytridiomycosis, a lethal fungal disease caused by Batrachochytrium dendrobatidis (Bd), is responsible for population declines and extinctions of amphibians worldwide. However, not all amphibian species are equally susceptible to the disease; some species persist in Bd enzootic regions with no population reductions. Recently, it has been shown that the amphibian skin microbiome plays a crucial role in the defense against Bd. Numerous bacterial isolates with the capacity to inhibit the growth of Batrachochytrium fungi have been isolated from the skin of amphibians. Here, we characterized eight Acinetobacter bacteria isolated from the frogs Agalychnis callidryas and Craugastor fitzingeri at the genomic level. A total of five isolates belonged to Acinetobacter pittii,Acinetobacter radioresistens, or Acinetobactermodestus, and three were not identified as any of the known species, suggesting they are members of new species. We showed that seven isolates inhibited the growth of Bd and that all eight isolates inhibited the growth of the phytopathogen fungus Botrytis cinerea. Finally, we identified the biosynthetic gene clusters that could be involved in the antifungal activity of these isolates. Our results suggest that the frog skin microbiome includes Acinetobacter isolates that are new to science and have broad antifungal functions, perhaps driven by distinct genetic mechanisms.

Las representaciones de apego y el estrés en las madres de niños nacidos pretérmino de muy bajo peso a los 2 años / Attachment representations and stress in mothers of very low birth weight preterm infants at two years of age

Introducción: Hay consenso en las investigaciones acerca de los efectos del nacimiento prematuro en las interacciones bebe-cuidador, aumentando los riesgos sobre el apego. Material y métodos: Se estudia a un grupo de 90 niños nacidos pretérmino con muy bajo peso (<1.500 g) seguidos en el Hospital de Cruces (Bizkaia, España) y 96 niños nacidos sanos a término, con edad y características sociodemográficas similares. El objetivo es evaluar, mediante una entrevista semiestructurada (entrevista R de representaciones maternas), el estrés materno y el modelo vincular sobre la base de las representaciones maternas de apego. Resultados: Los niños pretérmino tenían una inmadurez y riesgo biológico de grado medio-severo al nacimiento: EG media 29,9 semanas, PN 1.159,76 g y 57% más de 1 semana de hospitalización en la UCI. Las madres del grupo de los nacidos pretérmino presentaron más estrés durante el primer año de su hijo (61%) comparando con el grupo control (39%), pero no se encuentran diferencias en el modelo vincular o representacional de apego de las madres entre los 2 grupos. Discusión y conclusiones: Se confirma que el nacimiento pretérmino tiene gran influencia sobre el equilibrio emocional materno y la conveniencia de evaluar las reacciones de estrés en los padres y los signos de riesgo para el apego de esta población lo más temprano posible(AU)

Introduction: There is a consensus that prematurity could affect the risk of attachment impairment. Material and methods: We studied 90 very low birth weights preterm children (<1500 g) with follow-ups at Cruces Hospital (Bizkaia) and 96 healthy children born at term with similar age and sociodemographic characteristics. Our objective is to assess maternal stress and link model in accordance to attachment representations of mothers on both groups by using R Interview for Maternal Representations. Results: Preterm infants had a medium-to-severe degree of immaturity and biological risk: mean gestational age of 29.9 weeks and birth weight 1159.76 gr, with 57% staying in the ICU mayor 1 week. Mothers of preterm infants reported higher levels of stress during their first year of life (61%) than controls (39%), but no significant differences were found in link model (attachment representations) between the two groups. Discussion and conclusions: The results confirm that preterm birth has a great influence on maternal emotional responses, and indicate that stress responses in parents and alarm signs for attachment problems should be assessed as early as possible(AU)

[Attachment representations and stress in mothers of very low birth weight preterm infants at two years of age]. / Las representaciones de apego y el estrés en las madres de niños nacidos pretérmino de muy bajo peso a los 2 años.

INTRODUCTION: There is a consensus that prematurity could affect the risk of attachment impairment. MATERIAL AND METHODS: We studied 90 very low birth weights preterm children (<1500 g) with follow-ups at Cruces Hospital (Bizkaia) and 96 healthy children born at term with similar age and sociodemographic characteristics. Our objective is to assess maternal stress and link model in accordance to attachment representations of mothers on both groups by using R Interview for Maternal Representations. RESULTS: Preterm infants had a medium-to-severe degree of immaturity and biological risk: mean gestational age of 29.9 weeks and birth weight 1159.76 gr, with 57% staying in the ICU ≥ 1 week. Mothers of preterm infants reported higher levels of stress during their first year of life (61%) than controls (39%), but no significant differences were found in link model (attachment representations) between the two groups. DISCUSSION AND CONCLUSIONS: The results confirm that preterm birth has a great influence on maternal emotional responses, and indicate that stress responses in parents and alarm signs for attachment problems should be assessed as early as possible.

Generalizing CMAC architecture and training.

The cerebellar model articulation controller (CMAC) is a simple and fast neural-network based on local approximations. However, its rigid structure reduces its accuracy of approximation and speed of convergence with heterogeneous inputs. In this paper, we propose a generalized CMAC (GCMAC) network that considers different degrees of generalization for each input. Its representation abilities are analyzed, and a set of local relationships that the output function must satisfy are derived. An adaptive growing method of the network is also presented. The validity of our approach and methods are shown by some simulated examples.