Holobiont dysbiosis or acclimatation? Shift in the microbial taxonomic diversity and functional composition of a cosmopolitan sponge subjected to chronic pollution in a Patagonian bay.

Dysbiosis and acclimatization are two starkly opposing outcomes of altered holobiont associations in response to environmental pollution. This study assesses whether shifts in microbial taxonomic composition and functional profiles of the cosmopolitan sponge Hymeniacidon perlevis indicate dysbiotic or acclimatized responses to water pollution. To do so, sponge and water samples were collected in a semi-enclosed environment (San Antonio Bay, Patagonia, Argentina) from variably polluted sites (i.e., eutrophication, heavy metal contamination). We found significant differences in the microbiome of H. perlevis with respect to the pollution history of the sites. Several indicators suggested that acclimatization, rather than dysbiosis, explained the microbiome response to higher pollution: 1) the distinction of the sponge microbiome from the water microbiome; 2) low similarity between the sponge and water microbiomes at the most polluted site; 3) the change in microbiome composition between sponges from the different sites; 4) a high similarity in the microbiome among sponge individuals within sites; 5) a similar ratio of common sponge microbes to opportunistic microbes between sponges at the most and least polluted sites; and 6) a distinctive functional profile of the sponge microbiome at the most polluted site. This profile indicated a more expansive metabolic repertoire, including the degradation of pollutants and the biosynthesis of secondary metabolites, suggesting a relevant role of these microbial communities in the adaptation of the holobiont to organic pollution. Our results shed light on the rearrangement of the H. perlevis microbiome that could allow it to successfully colonize sites with high anthropogenic impact while resisting dysbiosis.

Cognitive abilities related to foraging behavior in Vespula vulgaris (Hymenoptera: Vespidae).

Vespula vulgaris is an invasive social wasp that has become established in many parts of the world. Plastic cognitive systems are expected to be advantageous for invasive species, given that they continuously face dynamic and unpredictable environments. We analyzed foraging behavior associated with undepleted and depleted resources. The wasps were trained to associate a certain location with food and we recorded their behavior after successive displacement of it. We also studied how long wasps continued to search for food that was no longer available and whether it was dependent on experience. We found that when wasps associated a certain location with food, they returned to the same site even though food was no longer available or had been displaced. Handling time remained constant, while relocation time and learning flights decreased with experience. With a food position change, learning flights increased and searching time varied with experience. When food was removed, hovering and landings were greatest in wasps that had the most experience with the resource, although extinction of the searching response was not dependent on experience. Our results illustrate the plasticity of wasp behavior in uncertain foraging contexts, which could have allowed the species to establish successfully in new habitats.

Detection of thermotolerant coliforms and SARS-CoV-2 RNA in sewage and recreational waters in the Ecuadorian coast: A call for improving water quality regulation.

Wastewater surveillance represents an alternative approach to regulating contamination and the early detection of infectious agents and outbreaks of diseases of public health importance. This study evaluated domestic wastewater effects on recreational waters in estuarine and seawater bodies in Guayas and Santa Elena provinces in Ecuador, South America. Fecal indicator bacteria (thermotolerant coliforms) served as key indicators for evaluation. Physical, chemical, and microbiological quality markers following the Ecuadorian environmental quality standard and the discharge of effluents to the water resource were analyzed. Samples were collected from 44 coastal sites and 2 oxidation lagoons during the dry and rainy seasons of 2020 and 2021, respectively. SARS-CoV-2 RNA was detected in samples with higher E. coli concentrations using reverse transcription quantitative PCR to detect the genes N and ORF1ab. All samples analyzed for SARS-CoV-2 showed Ct ˂ 40 for at least one gene. Four samples showed at least 20 genome copies of gene N per reaction. These were at an artisanal fishing port, an estuarine area (Palmar), a recreational bay, and an oxidation lagoon. A moderate correlation was found between SARS-CoV-2 RNA, thermotolerant coliform and E. coli (p-value ≤ 0.0037), and a strong and positive correlation between thermotolerant coliform and E. coli. (p-value ≤ 0.00001), highlighting the utility of these established parameters as a proxy of the virus. Significant differences were found in the concentrations of thermotolerant coliforms between seasons (p-value = 0.016) and sites (p-value = 0.005). The highest levels of coliforms were found in the dry season (63000 MPN/100 mL) in Anconcito and during the rainy season (14000 MPN/100 mL) at Esterillo in Playas County. It is recommended that the decentralized autonomous governments of the surveyed provinces in Ecuador implement urgent corrective actions and establish medium-term mechanisms to minimize a potential contamination route. Additional parameters must be included in the monitoring, such as Enterococcus and intestinal parasites, due to their public health implications. In the oxidation lagoons, maintenance actions must be carried out, including the dissolution of sediments, an increase in water retention times, and in situ treatment of the sludge, to improve the system's performance.

Comparing Single-Tooth Implant Placement With and Without Allogeneic Soft Tissue Augmentation: A Randomized Clinical Trial.

PURPOSE: To explore the effect of adding an allogeneic soft tissue graft at the time of single implant placement using a fully digital workflow for implant placement and restoration without making either analog or digital impressions. MATERIALS AND METHODS: A prospective randomized clinical study was performed enrolling 39 participants requiring single-tooth implants. The patients were randomized into one of two groups: (1) the graft group, which received an allogeneic dermal graft at the time of implant placement (n = 19), or (2) the nongraft group (n = 20). A fully digital surgical and restorative protocol was implemented for both groups. Intraoral scans were taken before implant placement (T0), at the time of final crown delivery (T1), and 1 year after placement (T2). Intraoral scans were aligned using Geomagic Control X 2020 software, and linear and volumetric changes in buccal tissues were measured at T0, T1, and T2. Implant survival, probing depths (PDs), and complications were recorded. Participants were asked to complete an Oral Health Impact Profile (OHIP)- 14 survey at T0 and T2. Marginal bone levels were measured at T0 and T2 on periapical radiographs. RESULTS: Overall, 39 participants completed surgery and restoration in the incisor, canine, premolar, and molar sites. Two early failures were recorded in central incisor positions (95% survival). Crown delivery without complication from the digital workflow (impressionless) was achieved for 36 out of 39 cases (92%), and implant depth control was the main challenge. At 1 year, 37 participants attended the follow-up appointment. Both groups showed gain in buccal tissue thickness without significant differences between the two groups for both linear and volumetric measurements (P > .05). Soft tissue grafting was associated with minimal added morbidity. The interproximal marginal bone changes were recorded as follows: -0.16 mm mesial and -0.12 mm distal for the graft group and -0.01 mm mesial and -0.11 mm distal for the nongraft group (P = .07 for mesial and .83 for distal). The OHIP score was significantly reduced at T2 compared to T0 (P = .003) for the entire cohort. CONCLUSIONS: Augmentation of the alveolar mucosa on the buccal aspect of single-tooth implants is associated with clinically favorable outcomes. A fully digital workflow has been validated to permit crown delivery on CAD/CAM abutments without implant impressions.

Sobrepeso y obesidad en infancias de Bariloche, Argentina: más allá de la alimentación y la actividad física / Childhood overweight and obesity in Bariloche, Argentina: Beyond eating habits and physical activity

La incidencia de sobrepeso y obesidad es alarmante en el mundo. En Argentina son escasos los estudios multifactoriales a pesar de los altos índices de sobrepeso y obesidad en la población infantil (SOI). En este estudio evaluamos la prevalencia de SOI y sus factores de riesgo asociados desde una perspectiva multicausal: analizamos hábitos de sueño, uso de pantallas, estrés crónico en niños y sus cuidadores, problemas de relación social, alimentación y actividad física. De los 397 niños de primer y séptimo grado que completaron los cuestionarios, el 41 % presentó SOI. Los niños con obesidad mostraron realizar menos actividad física, tener un menor consumo de alimentos protectores, más riesgos de trastornos del sueño, mayores niveles de estrés crónico (tanto en los niños como en sus cuidadores) y mayor índice de rechazo entre pares. En la mayoría de los niños se encontró un uso generalizado de pantallas antes de acostarse. El presente estudio evidencia la diversidad de factores asociados a esta problemática y destaca la conveniencia de utilizar un enfoque multidimensional para abordar la obesidad en la infancia. Asimismo, los resultados de este trabajo sugieren la necesidad de considerar los hábitos de vida como estrategia preventiva y terapéutica para el tratamiento de esta enfermedad desde etapas tempranas.

The incidence of overweight and obesity is alarming worldwide. In Argentina, multifactorial studies are scarce despite the high rates of childhood overweight and obesity (OW/OB). In this study we assessed the prevalence of childhood OW/OB and the associated risk factors from a multicausal perspective: we analyzed sleep habits, screen use, chronic stress in children and their caregivers, social relationship problems, eating habits, and physical activity. Of the 397 first and seventh graders who completed the questionnaires, 41% had childhood OW/OB. In children with obesity, a lower level of physical activity, a lower consumption of protective foods, a higher risk for sleep disorders, higher levels of chronic stress (in both children and their caregivers), and higher rates of peer rejection were observed. Widespread use of screens before bedtime was noted in most children. This study evidences the diversity of factors associated with childhood OW/OB and highlights the convenience of a multidimensional approach to address it. In addition, the results of this study suggest the need to consider lifestyle habits as a preventive and therapeutic strategy for the management of OW/OB from early stages.

High wax ester and triacylglycerol biosynthesis potential in coastal sediments of Antarctic and Subantarctic environments.

The wax ester (WE) and triacylglycerol (TAG) biosynthetic potential of marine microorganisms is poorly understood at the microbial community level. The goal of this work was to uncover the prevalence and diversity of bacteria with the potential to synthesize these neutral lipids in coastal sediments of two high latitude environments, and to characterize the gene clusters related to this process. Homolog sequences of the key enzyme, the wax ester synthase/acyl-CoA:diacylglycerol acyltransferase (WS/DGAT) were retrieved from 13 metagenomes, including subtidal and intertidal sediments of a Subantarctic environment (Ushuaia Bay, Argentina), and subtidal sediments of an Antarctic environment (Potter Cove, Antarctica). The abundance of WS/DGAT homolog sequences in the sediment metagenomes was 1.23 ± 0.42 times the abundance of 12 single-copy genes encoding ribosomal proteins, higher than in seawater (0.13 ± 0.31 times in 338 metagenomes). Homolog sequences were highly diverse, and were assigned to the Pseudomonadota, Actinomycetota, Bacteroidota and Acidobacteriota phyla. The genomic context of WS/DGAT homologs included sequences related to WE and TAG biosynthesis pathways, as well as to other related pathways such as fatty-acid metabolism, suggesting carbon recycling might drive the flux to neutral lipid synthesis. These results indicate the presence of abundant and taxonomically diverse bacterial populations with the potential to synthesize lipid storage compounds in marine sediments, relating this metabolic process to bacterial survival.

Childhood overweight and obesity in Bariloche, Argentina: Beyond eating habits and physical activity. / Sobrepeso y obesidad en infancias de Bariloche, Argentina: más allá de la alimentación y la actividad física.

The incidence of overweight and obesity is alarming worldwide. In Argentina, multifactorial studies are scarce despite the high rates of childhood overweight and obesity (OW/OB). In this study we assessed the prevalence of childhood OW/OB and the associated risk factors from a multicausal perspective: we analyzed sleep habits, screen use, chronic stress in children and their caregivers, social relationship problems, eating habits, and physical activity. Of the 397 first and seventh graders who completed the questionnaires, 41% had childhood OW/OB. In children with obesity, a lower level of physical activity, a lower consumption of protective foods, a higher risk for sleep disorders, higher levels of chronic stress (in both children and their caregivers), and higher rates of peer rejection were observed. Widespread use of screens before bedtime was noted in most children. This study evidences the diversity of factors associated with childhood OW/OB and highlights the convenience of a multidimensional approach to address it. In addition, the results of this study suggest the need to consider lifestyle habits as a preventive and therapeutic strategy for the management of OW/OB from early stages.

La incidencia de sobrepeso y obesidad es alarmante en el mundo. En Argentina son escasos los estudios multifactoriales a pesar de los altos índices de sobrepeso y obesidad en la población infantil (SOI). En este estudio evaluamos la prevalencia de SOI y sus factores de riesgo asociados desde una perspectiva multicausal: analizamos hábitos de sueño, uso de pantallas, estrés crónico en niños y sus cuidadores, problemas de relación social, alimentación y actividad física. De los 397 niños de primer y séptimo grado que completaron los cuestionarios, el 41 % presentó SOI. Los niños con obesidad mostraron realizar menos actividad física, tener un menor consumo de alimentos protectores, más riesgos de trastornos del sueño, mayores niveles de estrés crónico (tanto en los niños como en sus cuidadores) y mayor índice de rechazo entre pares. En la mayoría de los niños se encontró un uso generalizado de pantallas antes de acostarse. El presente estudio evidencia la diversidad de factores asociados a esta problemática y destaca la conveniencia de utilizar un enfoque multidimensional para abordar la obesidad en la infancia. Asimismo, los resultados de este trabajo sugieren la necesidad de considerar los hábitos de vida como estrategia preventiva y terapéutica para el tratamiento de esta enfermedad desde etapas tempranas.

Hair cortisol reduction and social integration enhancement after a mindfulness-based intervention in children.

BACKGROUND: Over recent decades, chronic stress at an early age has become a worrying health problem in children. We seek to evaluate an intervention involving mindfulness-based practices and prosocial activities in 7- to 8-year-old children. METHODS: Stress levels were determined using hair cortisol concentration (HCC), and social integration was measured by means of a sociogram. The program had previously proven to be effective in decreasing salivary cortisol levels and in favouring social integration in children. A total of 35 children participated in the study: 18 constituted the intervention group and 17 the wait-list group. In both groups, HCC and social integration were evaluated before and after the intervention conducted throughout an entire school year. RESULTS: The experimental group showed a significant reduction in HCC, as well as significant enhancement of social integration levels, whereas no changes were observed in the wait-list group. CONCLUSIONS: This is the first research to show that HCC, a reliable neuroendocrine indicator, decreased as a result of a mindfulness-based program. This successful outcome adds new evidence to previous findings regarding the reduction of chronic stress in children following participation in this program.

Microbial communities associated with kelp detritus in temperate and subantarctic intertidal sediments.

Kelp forests, among the most productive ecosystems on Earth, cover large areas of the South Atlantic coast. Sediment heterotrophic bacteria have a pivotal role in the degradation of kelp biomass, however, the response of sediment microbial communities to periodic kelp biomass inputs is mostly unknown. Here, we show that kelp biomass induced rapid changes in overlying water chemistry and shifts in sediment microbial communities, which differed in the experimental systems containing Macrocystis pyrifera (M) and Undaria pinnatifida (U) with sediments of the respective regions. We observed results compatible with the degradation of labile, high molecular weight compounds into smaller and more refractory compounds towards the end of the incubations. The capability of microbial communities to degrade alginate, the major component of kelp cell walls, significantly increased with respect to controls after kelp biomass addition (Absorbance at 235 nm 1.2 ± 0.3 and 1.0 ± 0.2 for M and U, respectively, controls <0.2, t = 4 days). Shifts in microbial community structure (based on 16S rRNA gene amplicon sequencing) were tightly related to the kelp treatment and, to a lesser extent, to the sediment provenance (Principal Coordinates Analysis, 80 % of variation explained in the first two axes). Dissolved oxygen, pH, salinity, alginolytic potential, Absorbance at 235 and 600 nm, total N, total C, and SUVA index correlated significantly with community structure. Differentially abundant populations between kelp-amended treatments and controls included members of the Flavobacteriia class (Algibacter and Polaribacter), and Gammaproteobacteria (Psychromonas and Marinomonas), among others. Metagenomes of M and U-amended sediments contained sequences from 18 of the 19 enzyme families related to alginate or fucoidan degradation. Specific taxonomic groups were associated with enzyme classes targeting different substrates, suggesting niche differentiation. This work expands our knowledge on the patterns of microbial assemblages from intertidal sediments in response to kelp biomass inputs.

Las prácticas de integración cuerpo-mente como promotoras de estados emocionales saludables / Mind­Body Integration Practices as Promoters of Healthy Emotional States / Práticas de integração corpo-mente como promotoras de estados emocionais saudáveis

Recientes investigaciones provenientes de diversos campos emergentes como la psiconeu-roinmunología, la medicina integrativa o la pigenética han dado cuenta de la estrecha vinculación entre los estados emocionales y la salud. El objetivo fue evaluar la eficacia de una intervención basada en la realización de prácticas de integración cuerpo-mente sobre la regulación emocional. Materiales y métodos: en 102 participantes, de entre 34 y 65 años de edad, se analizaron cambios en la Escala de Afectividad Positiva y Negativa (panas), antes y después de participar en la intervención propuesta, que se realizó durante ocho encuentros de seis horas de duración cada uno, a lo largo de cuatro meses. Resultados: se encontró un aumento en la afectividad positiva y una disminución en la afectividad negativa luego de la intervención. El índice de afectividad (i. e. afectividad positiva/afectividad negativa) se incrementó de una relación 2:1 a una relación 3:1. Esta última proporción ha sido asociada con estados saludables. Conclusiones: el estudio contribuye a demostrar el beneficio que brindan las prácticas de integración cuerpo-mente en la regulación emocional y la afectividad positiva. Esto podría propiciar un mayor bienestar psicofísico individual y colectivo.

Recent research from various emerging fields, such as psychoneuroimmunology, integra-tive medicine, and epigenetics, showed a close link between emotional states and health. This study was designed to evaluate the effectiveness of an intervention based on mind­body integration practices in emotional regulation. Materials and Methods: We evaluated changes in the positive and negative affectivity scale in 102 participants before and after the intervention, which was performed during eight meetings lasting 6 h each, for 4 months. Results: An increase in positive affectivity and a decrease in negative affectivity were found after the intervention. The affectivity index (i.e., positive affectivity/negative affectivity) increased from a 2:1 ratio to a 3:1 ratio. This latter ratio has been associated with healthy states. Conclusions: This study demonstrated that mind­body integration practices can confer to emotional regulation and positive affectivity. These beneficial effects could improve psychophysical well-being at both the individual and collective levels.

pesquisas recentes provenientes de vários campos emergentes, como a psiconeuroimuno-logia, medicina integrativa e epigenética, mostram a estreita ligação entre os estados emocionais e a saúde. O objetivo do presente trabalho é avaliar a eficácia de uma intervenção baseada na realização de práticas de integração corpo-mente, na regulação emocional. Materiais e métodos: em 102 participantes, entre 34 e 65 anos, foram analisadas as mudanças na escala de afetividade positiva e negativa (panas) antes e após a participação na intervenção proposta, que foi realizada durante 8 encontros de 6 horas de duração cada, durante 4 meses. Resultados: houve um aumento da afetividade positiva e diminuição da afetividade negativa após a intervenção. O índice de afetividade (ou seja, afetividade positiva/afetivi-dade negativa) aumentou, passando de uma relação de 2:1 para uma relação de 3:1, esta última propor-ção tem sido associada a estados saudáveis. Conclusões: o presente estudo contribui para demonstrar o benefício proporcionado pelas práticas de integração corpo-mente na regulação emocional e na afetivi-dade positiva. Isso poderia propiciar um maior bem-estar psicofísico a nível individual e coletivo.

Microbial assemblages associated with the invasive kelp Undaria pinnatifida in Patagonian coastal waters: Structure and alginolytic potential.

Undaria pinnatifida is a brown algae native to Asia that has settled in various regions worldwide, periodically contributing with large quantities of C and nutrients during its annual cycle. In this work, we analyzed a coastal site in Patagonia (Argentina) that has been colonized for three decades by U. pinnatifida, focusing on associated microbial communities in three different compartments. An important influence of algae was observed in seawater, especially in the bottom of the algal forest during the austral summer (January) at the moment of greater biomass release. This was evidenced by changes in DOC concentration and its quality indicators (higher Freshness and lower Humification index) and higher DIC. Although maximum values of NH4 and PO4 were observed in January, bottom water samples had lower concentrations than surface water, suggesting nutrient consumption by bacteria during algal DOM release. Concomitantly, bacterial abundance peaked, reaching 4.68 ± 1.33 × 105 cells mL -1 (January), showing also higher capability of degrading alginate, a major component of brown algae cell walls. Microbial community structure was influenced by sampling date, season, sampling zone (surface or bottom), and environmental factors (temperature, salinity, pH, dissolved oxygen, nutrients). Samples of epiphytic biofilms showed a distinct community structure compared to seawater, lower diversity, and remarkably high alginolytic capability, suggesting adaptation to degrade algal biomass. A high microdiversity of populations of the genus Leucothrix (Gammaproteobacteria, Thiotrichales) that accounted for a large fraction of epiphytic communities was observed, and changed over time. Epiphytic assemblages shared more taxa with bottom than with surface seawater assemblages, indicating a certain level of exchange between communities in the forest surroundings. This work provides insight into the impact of U. pinnatifida decay on seawater quality, and the role of microbial communities on adapting to massive biomass inputs through rapid DOM turnover.

Acute toxicity of microplastic fibers to honeybees and effects on foraging behavior.

Microplastics (MPs) are considered emerging and persistent pollutants, although most of the research has been conducted on marine environments. Declines in honeybee populations have been reported globally, and recently, microplastic pollution has been considered a possible cause of this. Thus, we aimed to determine acute toxicity of polyester fibers and their effects on foraging behavior in honeybees. To test this, we conducted an oral acute toxicity bioassay, testing the effect of MPs on individual honeybees, and we studied the foraging behavior of honeybees when exposed to food and water containing MPs. We observed no mortality in honeybees fed with sucrose solution containing 100 mg MP/L after 24 and 48 h. Upon bee dissection of the digestive tract, we found 1.27 ± 1.5 fibers per bee, showing a mean (±SE) of 0.92 (±1.14) and 0.32 (±0.70) in their gut and crop respectively. The length of these microfibers ranged between 0.05 and 1.24 mm with a mean (±SE) of 0.42 (±0.25) mm. Although we did not find any preference or avoidance of MPs when presented in sucrose solutions and water; bees consumed MP-free solutions faster than solutions with 10 and 100 mg MPs/L. This might be due to changes in the viscosity of the solutions containing plastic and has implications for the impact of microplastic pollution on insects. Results suggest that MPS do not pose a threat to honeybees in the short term, based on the lack of acute mortality. However, bee foraging behavior does not prevent them from ingesting MPs present in water or resources which potentially might cause lethal long-term effects of MPs.

Cannabis Varieties Can Be Distinguished by Achene Shape Using Geometric Morphometrics.

Introduction: Cannabis plant uses are widespread across human cultures. The current tendency is to classify Cannabis varieties into chemovars upon their chemical fingerprint, mainly cannabinoids and terpenoids content. The identification of chemovars has important medical implications; however, their pharmacological characterization is costly and time consuming. The goal of this study was to assess whether achene shape variation could be related to Cannabis varieties with contrasting cannabinoid concentrations, as a first approach to chemovar identification. Methods: We used two-dimensional geometric morphometrics (GM) of the achenes and multivariate statistical analysis. We used achenes from five varieties, two from Type II chemotype (expressing both tetrahydrocannabinol [THC] and cannabidiol [CBD]), two Type I (THC-only), and one Type III (CBD-only). Results: The achenes from the different chemotypes were clearly distinguishable. No significant differences between varieties from the same chemotype were observed. The varieties with high THC concentration (Type I) were rounded and bigger, whereas achene from varieties containing only CBD (Type III) had a slender shape with smaller size. Conclusion: Achene shape variation is a potential biomarker of cannabinoid content in the plant flowers. Further studies are needed to confirm the suitability of GM methods for high-throughput screening of Cannabis cultivars, including larger diversity of varieties, and taking into account growth conditions, which can also influence plant chemical fingerprint.

Spatial memory in Vespula germanica wasps: A pilot study using a Y-maze assay.

In the present study we analysed spatial learning in Vespula germanica wasps when dealing with a walking Y-maze. We recorded the time taken to leave the maze during two consecutive visits and which of the two short arms was chosen to exit. Two treatments were conducted to evaluate whether wasps learned to leave the Y-maze guided either by spatial or visual cues. In Treatment 1, the colour of both arms remained unchanged between two consecutive visits; and in Treatment 2, the position of the coloured arm was switched after the first trial. Our results demonstrated that the time taken to exit the maze on the second trial was less than half in both treatments and wasps left the maze from the previously chosen arm, irrespective of its colour. This is the first study to demonstrate spatial learning in V. germanica wasps by using a walking Y-maze. Free flying wasps learned to enter the Y-maze on their own volition, walk through it, collect food and find their way out more rapidly after a single foraging experience. The current experimental device is suitable for the evaluation of spatial memory processes and exploratory behaviour in this species.

How behavioral plasticity enables foraging under changing environmental conditions in the social wasp Vespula germanica (Hymenoptera: Vespidae).

The foraging strategy at abundant resources of the social wasp Vespula germanica includes scanning in the direction of the nest while memorizing resource-specific landmarks and contextual cues. In the present study, we sought to explore wasps' behavioral plasticity on foraging trips to resources whose location and composition changed after a single visit. We evaluated how contextual modifications of food displacement and replacements 60 cm apart from the original site, affect re-orientation for re-finding previously memorized food resources. The results showed that wasps detected and collected the resource faster when more changes were introduced on the following visit. If returning foragers discovered several modifications on both the location and the kind of resource, they collected food more rapidly from the displaced dish, than if only a single parameter in the environment had been changed. These findings illustrate the grade of behavioral plasticity in V. germanica while foraging on abundant resources, which may contribute to the understanding of the prodigious invasive success of this species in anthropized environments.

Evidence of associative blocking during foraging in the social wasp Vespula germanica.

While foraging, Vespula germanica usually return to abundant food sites. During this relocation behavior, these wasps learn to identify contextual cues associated with food position. We analyzed associative blocking in this species, that is, how an association with a conditioned stimulus (CS1) blocks subsequent learning when a novel stimulus (CS2) is added on a second foraging visit. Three groups of wasps (A, B, and C; total 74 individual wasps) were observed while collecting meat during one or two consecutive visits. In group A, an environmental cue (CS1) was paired with food placed at a specific site, and on the second visit, a second cue (CS2) was added while food remained in the same position. In a subsequent testing phase, CS1 was removed and the food source displaced nearby. We then recorded the number of hovers performed over the empty dish (previously baited). Group A wasps appeared to ignore the addition of CS2 on their second visit because they performed fewer hovers over the learned site. For group A, the duration of the decision-making process to finally fly toward the baited dish was shorter than when CS1 and CS2 were presented together on their first visit (group B). This is the first study to demonstrate the occurrence of associative blocking in vespids, confirming that a prior foraging experience influences subsequent food relocation in V. germanica. Our findings reveal that first learning episodes block further associations with novel contextual cues, contributing to understanding of complex cognitive processes involved in V. germanica´s foraging behavior.

16S rRNA gene amplicon dataset of prokaryotic communities from a subantarctic marine ecosystem: Ushuaia Bay and surrounding waters.

We provide a 16S rRNA gene dataset of prokaryotic assemblages of a subantarctic marine ecosystem. Samples were collected at 2 stations (one near Ushuaia Bay and the other close to Bridges islands in the Beagle Channel). At each station, 2 depths (subsurface and bottom waters) were sampled in february, march, may and september during 2018, giving a total of 10 samples. 16S rRNA gene amplicon sequencing (V4 hypervariable region) was performed with the Illumina MiSeq platform. A total of 1116 amplicon sequence variants (ASVs) were recovered from the dataset. The sequences were taxonomically assigned to Alphaproteobacteria (23 ± 2%, mean ± standard error), Gammaproteobacteria (17 ± 1.5%), Flavobacteriia (8 ± 2%), Deltaproteobacteria (3.7 ± 0.5%), Acidimicrobiia (1.7 ± 0.1%), Planctomycetia (1.9 ± 0.4%), and AB16 group (1.7 ± 0.3%). Sequences affiliated with Archaea were abundant, reaching one third of analyzed sequences, mainly Thaumarchaeota (22 ± 3%), and Thermoplasmata (10 ± 1%). Together, sequences assigned to all these groups accounted for more than 90% of the sequences. This dataset constitutes a valuable resource for future scientific research aiming to unveil the role of these communities in ecosystem services such as carbon and nutrient cycling, and pollutants degradation. This will turn into benefits for future environmental monitoring and preservation actions, considering the tangible heritage of Ushuaia Bay and surrounding waters.

Predominance and high diversity of genes associated to denitrification in metagenomes of subantarctic coastal sediments exposed to urban pollution.

The aim of this work was to characterize the microbial nitrogen cycling potential in sediments from Ushuaia Bay, a subantarctic environment that has suffered a recent explosive demographic growth. Subtidal sediment samples were retrieved in triplicate from two urban points in the Bay, and analyzed through metagenomic shotgun sequencing. Sequences assigned to genes related to nitrification, nitrate reduction and denitrification were predominant in this environment with respect to metagenomes from other environments, including other marine sediments. The nosZ gene, responsible for nitrous oxide transformation into di-nitrogen, presented a high diversity. The majority of NosZ sequences were classified as Clade II (atypical) variants affiliated to different bacterial lineages such as Bacteroidetes, Chloroflexi, Firmicutes, Proteobacteria, Verrucomicrobia, as well as to Archaea. The analysis of a fosmid metagenomic library from the same site showed that the genomic context of atypical variants was variable, and was accompanied by distinct regulatory elements, suggesting the evolution of differential ecophysiological roles. This work increases our understanding of the microbial ecology of nitrogen transformations in cold coastal environments and provides evidence of an enhanced denitrification potential in impacted sediment microbial communities. In addition, it highlights the role of yet overlooked populations in the mitigation of environmentally harmful forms of nitrogen.