A comprehensive dataset integrating household energy consumption and weather conditions in a north-eastern Mexican urban city.

The prediction of domestic electricity consumption is relevant because it helps to plan energy production, among many other benefits. In this work a dataset was collected from one house in an urban city of north-east of Mexico. An ad-hoc acquisition system was implemented to collect the data using a smart meter and the open weather API. The data was collected every minute over a period of 14 months since November 5, 2022, to January 5, 2024. The dataset contains 605,260 samples of 19 variables related with energy consumption and weather data. This dataset is specifically tailored for predicting domestic energy consumption and understanding consumption behaviours, filling a void in the existing literature where such datasets for Mexico are scarce. Moreover, the multivariate nature of the dataset allows researchers to investigate and propose new techniques for forecasting or pattern classification using multivariate data collected in a real scenario.

Computational Techniques for Eye Movements Analysis towards Supporting Early Diagnosis of Alzheimer's Disease: A Review.

An opportune early diagnosis of Alzheimer's disease (AD) would help to overcome symptoms and improve the quality of life for AD patients. Research studies have identified early manifestations of AD that occur years before the diagnosis. For instance, eye movements of people with AD in different tasks differ from eye movements of control subjects. In this review, we present a summary and evolution of research approaches that use eye tracking technology and computational analysis to measure and compare eye movements under different tasks and experiments. Furthermore, this review is targeted to the feasibility of pioneer work on developing computational tools and techniques to analyze eye movements under naturalistic scenarios. We describe the progress in technology that can enhance the analysis of eye movements everywhere while subjects perform their daily activities and give future research directions to develop tools to support early AD diagnosis through analysis of eye movements.

Testing the effects of heterozygosity on growth rate plasticity in the seaweed Gracilaria chilensis (Rhodophyta).

Heterozygosity has been positively associated with fitness and population survival. However, the relationship between heterozygosity and adaptive phenotypic plasticity (i.e., plasticity which results in fitness homeostasis or improvement in changing environments) is unclear and has been poorly explored in seaweeds. In this study, we explored this relationship in the clonal red seaweed, Gracilaria chilensis by conducting three growth rate plasticity experiments under contrasting salinity conditions and by measuring heterozygosity with five microsatellite DNA markers. Firstly, we compared growth rate plasticity between the haploid and diploid phases. Secondly, we compared growth rate plasticity between diploids with different numbers of heterozygous loci. Finally, we compared growth rate plasticity between diploid plants from two populations that are expected to exhibit significant differences in heterozygosity. We found that, (i) diploids displayed a higher growth rate and lower growth rate plasticity than haploids, (ii) diploids with a higher number of heterozygous loci displayed lower growth rate plasticity than those exhibiting less heterozygosity, and (iii) diploid sporophytes from the population with higher heterozygosity displayed lower growth rate plasticity than those with lower heterozygosity. Accordingly, this study suggests that heterozygosity is inversely related to growth rate plasticity in G. chilensis. However, better genetic tools in seaweeds are required for a more definitive conclusion on the relationship between heterozygosity and phenotypic plasticity.

Contextualización del inicio sexual y barreras individuales del uso de anticonceptivos en adolescentes de Lima, Huamanga e Iquitos / Contextualization of sexual initiation and individual barriers to the use of contraceptives by adolescents of Lima, Huamanga, and Iquitos

RESUMEN Objetivos . Contextualizar el inicio sexual y las barreras individuales hacia el uso de anticonceptivos en adolescentes, con conocimiento adecuados sobre anticoncepción y enfermedades de transmisión sexual. Materiales y métodos. Se desarrolló un estudio cuanticualitativo en adolescentes procedentes de ciudades con altas tasas de embarazo: Iquitos, Huamanga y Lima. La convocatoria se realizó a través de Facebook, luego se aplicaron encuestas para seleccionar a los adolescentes que cumplían los criterios de inclusión y, finalmente, se realizaron entrevistas para abordar el tema en profundidad. Resultados . Participaron 33 mujeres y 23 varones adolescentes urbanos, con edades entre 18 y 19 años. La edad de inicio sexual osciló entre los 14 y 16 años; las principales razones de inicio sexual en los varones fue el deseo sexual; en las mujeres fue la presión de la pareja; la persona con la que se iniciaron fue, principalmente, una pareja ocasional en los varones, y en las mujeres fue "su enamorado". Se identificaron barreras individuales en relación al uso de anticonceptivos como la estabilidad de la pareja, la responsabilidad de la mujer al usar anticonceptivos, la limitada capacidad de negociación y temor al abandono del varón por exigir su uso, además de la reducción de la sensibilidad sexual generada por el uso del condón. Conclusiones. Estas barreras limitan el uso de anticonceptivos, sugiriendo la necesidad de desarrollar estrategias específicas para fortalecer las habilidades interpersonales del adolescente que se extienden más allá de ofrecer información acerca de los riesgos del sexo sin protección.

ABSTRACT Objectives. To contextualize sexual initiation and barriers to the use of contraceptives by adolescents as well as the acquisition of adequate knowledge regarding contraception and sexually transmitted diseases. Materials and methods. This quantitative and qualitative study evaluated adolescents living in three cities with high pregnancy rates in Peru: Iquitos, Huamanga, and Lima. Subjects were invited to participate in the study via Facebook. Questionnaires were then used to select adolescents who met the inclusion criteria, and interviews were conducted to obtain detailed data regarding the study topic. Results. A total of 33 women and 23 men aged 18 to 19 years participated in the study. The age of onset of sexual activity ranged from 14 to 16 years; the main reasons for sexual initiation were sexual desire among men and pressure from the partner among women; in most cases, the sexual partner was an occasional companion for men and a boyfriend for women. The barriers related to the use of contraceptives were the financial stability of the partner, responsibility of the female partner when using contraceptives, limited capacity to negotiate choices, fear of abandonment by the male partner for demanding the use of contraceptives, and the reduction of sexual sensitivity with the use of condoms. Conclusions. The barriers identified in this study limit the use of contraceptives and indicate the need to develop specific strategies to strengthen the interpersonal skills of adolescents and provide accurate information about the risks of unprotected sex.

Modulatory effect of the exudates released by the brown kelp Lessonia spicata on the toxicity of copper in early developmental stages of ecologically related organisms.

Lessonia spicata is a key dominant species along the Pacific coast of South America, providing a habitat for many organisms. However, this role can be affected by abiotic stress, such as metals. To counteract the toxic effect, L. spicata, among other seaweeds, releases exudates that bind metals. In this study, tolerances to copper of organisms related to the kelp forest (spores of Ulva lactuca (Chlorophyceae) and L. spicata (Phaeophyceae) and Zoea I of Taliepus dentatus (Milne-Edwards, Crustacea)) were studied; then, exudates are assessed by their protective effect. Exudates increase the 48-h 50% effective concentration (EC50) of the germination of spores from 8 to 23 µg Cu L-1 for U. lactuca and from 119 to 213 µg Cu L-1 for L. spicata and the survival of the larvae Zoea I 48-h 50% of lethal concentration (LC50) from 144 to 249 µg Cu L-1. Results indicated that exudates had a protective effect. Each species is specifically sensitive to copper. Crab larvae Zoea I were able to support higher doses, and exposure before hatching increased their tolerance.

Coalescing red algae exhibit noninvasive, reversible chimerism.

Chimerism is produced by the somatic fusion of two or more genetically distinct conspecific individuals. In animals, the main cost of fusion is competition between genetically different cell lineages and the probability of original cell line replacement by more competitive invasive lines, which limits its natural frequency (3%-5%). In red and brown seaweeds, chimerism is widespread (27%-53%), seemingly without the negative outcomes described for animals. The rigidity of cell walls in macroalgae prevents cell motility and invasions. In addition, in moving waters, most somatic fusions involve the holdfast. Histological observations in laboratory-built bicolor macroalgal chimeras indicated that upright axes emerge from the base of plants by proliferation and vertical growth of discrete cell groups that include one or just a few of the cell lineages occurring in the holdfasts. Laboratory experiments showed growth competition between cell lineages, thus explaining lineage segregation during growth along originally chimeric erect axes. Genotyping of the axes showed more heterogeneous tissues basally, but apically more homogeneous ones, generating a vertical gradient of allele abundance and diversity. The few chimeric primary branches produced, eventually became homogenous after repeated branching. Therefore, coalescing macroagae exhibit a unique pattern of post-fusion growth, with the capacity to reverse chimerism. This pattern is significantly different from those in animals and land plants, suggesting chimerism is a biologically heterogeneous concept.

[Contextualization of sexual initiation and individual barriers to the use of contraceptives by adolescents of Lima, Huamanga, and Iquitos]. / Contextualización del inicio sexual y barreras individuales del uso de anticonceptivos en adolescentes de Lima, Huamanga e Iquitos.

OBJECTIVES.: To contextualize sexual initiation and barriers to the use of contraceptives by adolescents as well as the acquisition of adequate knowledge regarding contraception and sexually transmitted diseases. MATERIALS AND METHODS.: This quantitative and qualitative study evaluated adolescents living in three cities with high pregnancy rates in Peru: Iquitos, Huamanga, and Lima. Subjects were invited to participate in the study via Facebook. Questionnaires were then used to select adolescents who met the inclusion criteria, and interviews were conducted to obtain detailed data regarding the study topic. RESULTS.: A total of 33 women and 23 men aged 18 to 19 years participated in the study. The age of onset of sexual activity ranged from 14 to 16 years; the main reasons for sexual initiation were sexual desire among men and pressure from the partner among women; in most cases, the sexual partner was an occasional companion for men and a boyfriend for women. The barriers related to the use of contraceptives were the financial stability of the partner, responsibility of the female partner when using contraceptives, limited capacity to negotiate choices, fear of abandonment by the male partner for demanding the use of contraceptives, and the reduction of sexual sensitivity with the use of condoms. CONCLUSIONS.: The barriers identified in this study limit the use of contraceptives and indicate the need to develop specific strategies to strengthen the interpersonal skills of adolescents and provide accurate information about the risks of unprotected sex.

OBJETIVOS: . Contextualizar el inicio sexual y las barreras individuales hacia el uso de anticonceptivos en adolescentes, con conocimiento adecuados sobre anticoncepción y enfermedades de transmisión sexual. MATERIALES Y MÉTODOS.: Se desarrolló un estudio cuanticualitativo en adolescentes procedentes de ciudades con altas tasas de embarazo: Iquitos, Huamanga y Lima. La convocatoria se realizó a través de Facebook, luego se aplicaron encuestas para seleccionar a los adolescentes que cumplían los criterios de inclusión y, finalmente, se realizaron entrevistas para abordar el tema en profundidad. RESULTADOS: . Participaron 33 mujeres y 23 varones adolescentes urbanos, con edades entre 18 y 19 años. La edad de inicio sexual osciló entre los 14 y 16 años; las principales razones de inicio sexual en los varones fue el deseo sexual; en las mujeres fue la presión de la pareja; la persona con la que se iniciaron fue, principalmente, una pareja ocasional en los varones, y en las mujeres fue "su enamorado". Se identificaron barreras individuales en relación al uso de anticonceptivos como la estabilidad de la pareja, la responsabilidad de la mujer al usar anticonceptivos, la limitada capacidad de negociación y temor al abandono del varón por exigir su uso, además de la reducción de la sensibilidad sexual generada por el uso del condón. CONCLUSIONES.: Estas barreras limitan el uso de anticonceptivos, sugiriendo la necesidad de desarrollar estrategias específicas para fortalecer las habilidades interpersonales del adolescente que se extienden más allá de ofrecer información acerca de los riesgos del sexo sin protección.

[Evaluation of the cost-effectiveness of two alternative human papillomavirus vaccines as prophylaxis against uterine cervical cancer]. / Evaluación costo-efectividad de dos alternativas de vacunación para el virus del papiloma humano en la prevención del cáncer cervical uterino.

OBJECTIVES.: To determine the cost-effectiveness of human papillomavirus (HPV) vaccination and cervical lesion screening versus screening alone for the prevention of uterine cervical cancer (UCC). MATERIALS AND METHODS.: This cost-effectiveness evaluation from the perspective of the Ministry of Health employed a Markov model with a 70-year time horizon and three alternatives for UCC prevention (screening alone, screening + bivalent vaccine, and screening + quadrivalent vaccine) in a hypothetical cohort of 10-year-old girls. RESULTS.: Our model, which was particularly sensitive to variations in coverage and in the prevalence of persistent infection by oncologic genotypes not included in the vaccine, revealed that HPV vaccination and screening is more cost-effective than screening alone, assuming a payment availability from S/ 2 000 (US dollars (USD) 1 290.32) per subject. In the deterministic analysis, the bivalent vaccine was marginally more cost-effective than the quadrivalent vaccine (S/ 48 [USD 30.97] vs. S/ 166 [USD 107.10] per quality-adjusted life-year, respectively). However, in the probabilistic analysis, both interventions generated clouds of overlapping points and were thus cost-effective and interchangeable, although the quadrivalent vaccine tended to be more cost-effective. CONCLUSIONS.: Assuming a payment availability from S/ 2000 [USD 1,290.32], screening and vaccination were more cost-effective than screening alone. The difference in cost-effectiveness between the two vaccines lacked probabilistic robustness, and therefore the vaccines can be considered interchangeable from a cost-effectiveness perspective.

[Barriers to implementing screening, brief intervention and referral to treatment for substance use in HIV/AIDS health services in Peru]. / Barreras para implementar el despistaje, intervenciones breves y referencia al tratamiento por problemas de consumo de alcohol y otras drogas en hospitales que atienden personas que viven con el VIH/SIDA en el Perú.

OBJECTIVES.: Screening and treatment for substance use among people living with HIV/AIDS (PLWHA) is highly recommended. Nevertheless, in Peru healthcare for PLWHA does not include a standardized or systematic assessment to identify substance use. The aim of this study was to assess the feasibility of implementing screening, brief intervention and referral to treatment (SBIRT) in healthcare settings attending people living with PLWHA. MATERIALS AND METHODS.: After providing training in SBIRT for PLWHA's healthcare personnel (including nurses and physicians) focus groups were conducted to explore knowledge, beliefs and perceived barriers to implementation and interviews were conducted to assess the barriers and facilitators of two tertiary hospitals in Lima, Peru. RESULTS.: focus groups and interviews' thematic coding revealed three dimensions: 1) the unknown extent of substance use within PLWHA, 2) space and time limitations hinder completion of brief interventions during routine visits, and 3) insufficient access to substance use treatment appropriate for HIV patients. CONCLUSIONS.: Multiple barriers, including lack of awareness of substance use problems, limited space and time of providers, and lack of specialized services to refer patients for treatment make it difficult to implement SBIRT in the Peruvian healthcare system.

Barreras para implementar el despistaje, intervenciones breves y referencia al tratamiento por problemas de consumo de alcohol y otras drogas en hospitales que atienden personas que viven con el VIH/SIDA en el Perú / Barriers to implementing screening, brief intervention and referral to treatment for substance use in HIV/AIDS health services in Peru

RESUMEN Objetivos. Evaluar la factibilidad de implementar la detección, intervención breve y referencia a tratamiento (SBIRT, por sus siglas en inglés) en los servicios de atención para personas viviendo con el virus de inmunodeficiencia humana/ síndrome de inmunodeficiencia adquirido (PVVS). Materiales y métodos. Se realizó un estudio de tipo cualitativo, luego de capacitar profesionales de salud (incluyendo, enfermeras y médicos) que proveen atención de salud a PVVS en la aplicación del SBIRT, se realizaron grupos focales para explorar las barreras percibidas para su implementación y se realizaron entrevistas para evaluar las barreras y facilitadores en dos hospitales de tercer nivel de Lima, Perú. Resultados. La codificación temática de los grupos focales y las entrevistas revelaron tres dimensiones principales de barreras: 1) el desconocimiento acerca del consumo de sustancias en las PVVS; 2) limitaciones de espacio y tiempo que dificultan las intervenciones breves durante las visitas de rutina, y 3) insuficientes servicios con capacidades para el tratamiento el uso de sustancias apropiadas donde puedan ser referidos los pacientes con estos problemas. Conclusiones. Múltiples barreras, incluyendo el desconocimiento por los problemas de consumo de sustancias, limitaciones de espacio y tiempo de los profesionales, y carencia de servicios especializados a donde referir los pacientes para un cuidado especializado, haría difícil implementar SBIRT en un contexto como el del sistema de salud peruano.

ABSTRACT Objectives. Screening and treatment for substance use among people living with HIV/AIDS (PLWHA) is highly recommended. Nevertheless, in Peru healthcare for PLWHA does not include a standardized or systematic assessment to identify substance use. The aim of this study was to assess the feasibility of implementing screening, brief intervention and referral to treatment (SBIRT) in healthcare settings attending people living with PLWHA. Materials and methods. After providing training in SBIRT for PLWHA's healthcare personnel (including nurses and physicians) focus groups were conducted to explore knowledge, beliefs and perceived barriers to implementation and interviews were conducted to assess the barriers and facilitators of two tertiary hospitals in Lima, Peru. Results. focus groups and interviews' thematic coding revealed three dimensions: 1) the unknown extent of substance use within PLWHA, 2) space and time limitations hinder completion of brief interventions during routine visits, and 3) insufficient access to substance use treatment appropriate for HIV patients. Conclusions. Multiple barriers, including lack of awareness of substance use problems, limited space and time of providers, and lack of specialized services to refer patients for treatment make it difficult to implement SBIRT in the Peruvian healthcare system.

Evaluación costo-efectividad de dos alternativas de vacunación para el virus del papiloma humano en la prevención del cáncer cervical uterino / Evaluation of the cost-effectiveness of two alternative human papillomavirus vaccines as prophylaxis against uterine cervical cancer

RESUMEN Objetivos. Determinar la relación costo-efectividad de la vacunación contra el (virus del papiloma humano) VPH y el tamiz de lesiones cervicales, frente a un programa de tamiz solo. Materiales y métodos. Se realizó una evaluación costo-efectividad y se empleó un modelo de Markov, con un horizonte temporal de 70 años y tres alternativas de prevención para el (cáncer del cuello uterino) CCU (tamiz solo, tamiz + vacuna bivalente, y tamiz + vacuna cuadrivalente), en una cohorte hipotética de niñas de diez años, desde la perspectiva del Ministerio de Salud. Resultados. La vacunación contra el VPH y tamiz es más costo-efectiva que el tamiz solo a partir de una voluntad de pago de S/ 2000 (USD 1 290,32). En el análisis determinístico, la vacuna bivalente es marginalmente más costo-efectiva que la vacuna cuadrivalente (S/ 48 [USD 30,97] frente a S/ 166 [USD 107,10] por AVAC, respectivamente). Sin embargo, en el análisis probabilístico ambas intervenciones generan nubes de puntos superpuestos, con una tendencia de la vacuna cuadrivalente a ser más costo-efectiva. Es decir, ambas son costo-efectivas y, por ende, intercambiables. El modelo fue especialmente sensible a variaciones de la cobertura y en la prevalencia de infección persistente por genotipos oncológicos no incluidos en la vacuna. Conclusiones. A partir de una disponibilidad de pago de S/ 2000 [USD 1 290,32] el tamiz y la vacunación son más costo-efectivos que el tamiz solo. La diferencia de costo-efectividad entre ambas vacunas carece de robustez probabilística y ambas vacunas pueden considerarse intercambiables desde la perspectiva costo-efectividad.

ABSTRACT Objectives. To determine the cost-effectiveness of human papillomavirus (HPV) vaccination and cervical lesion screening versus screening alone for the prevention of uterine cervical cancer (UCC). Materials and methods. This cost-effectiveness evaluation from the perspective of the Ministry of Health employed a Markov model with a 70-year time horizon and three alternatives for UCC prevention (screening alone, screening + bivalent vaccine, and screening + quadrivalent vaccine) in a hypothetical cohort of 10-year-old girls. Results. Our model, which was particularly sensitive to variations in coverage and in the prevalence of persistent infection by oncologic genotypes not included in the vaccine, revealed that HPV vaccination and screening is more cost-effective than screening alone, assuming a payment availability from S/ 2 000 (US dollars (USD) 1 290.32) per subject. In the deterministic analysis, the bivalent vaccine was marginally more cost-effective than the quadrivalent vaccine (S/ 48 [USD 30.97] vs. S/ 166 [USD 107.10] per quality-adjusted life-year, respectively). However, in the probabilistic analysis, both interventions generated clouds of overlapping points and were thus cost-effective and interchangeable, although the quadrivalent vaccine tended to be more cost-effective. Conclusions. Assuming a payment availability from S/ 2000 [USD 1,290.32], screening and vaccination were more cost-effective than screening alone. The difference in cost-effectiveness between the two vaccines lacked probabilistic robustness, and therefore the vaccines can be considered interchangeable from a cost-effectiveness perspective.

Evaluación del valor diagnóstico de la detección de NS1 en pacientes con dengue agudo / Diagnostic value of NS1 detection in serum from acute dengue patients

El dengue es endemo-epidémico en Colombia y gran parte de nuestra población está en riesgo de padecer esta enfermedad. Uno de los principales problemas en el manejo del dengue es la dificultad para diagnosticar tempranamente esta arbovirosis, ya que la enfermedad presenta un cuadro clínico de evolución inespecífica, por lo cual es indispensable contar con herramientas diagnósticas rápidas y efectivas. El presente trabajo tiene como objetivo evaluar el valor diagnóstico de la detección de la proteína viral NS1 en pacientes con sospecha de dengue agudo, provenientes del Departamento de Cundinamarca, a quienes previamente se les había realizado detección de IgM en el Laboratorio de Salud Pública de Cundinamarca; de éstos, 44 muestras correspondían a pacientes con una prueba IgM positiva y las otras 44 a pacientes con una prueba de IgM negativa para dengue. A todas las muestras de suero se les practicó la prueba mediante el sistema Pan-E Dengue Early ELISA™ (Panbio) para la detección de NS1. Al hacer el análisis estadístico, se obtuvo una concordancia moderada entre las dos pruebas diagnósticas. Además, se encontró que 40 % de las muestras positivas para NS1, habían sido previamente reportadas como negativas de acuerdo con el resultado de IgM. De igual forma, se encontró enfermedad grave a menor edad y diferencias significativas en la presencia de erupción cutánea, ausencia de diarrea, leucocitos de menos de 4.000 células/μl y menos de 180.000 plaquetas/μl, al comparar los resultados positivos y negativos de cada prueba. Se puede concluir que la determinación de NS1 es necesaria en los casos sospechosos de dengue agudo y, junto con la determinación de IgM, representa un complemento eficiente para el diagnóstico, agilizando la instauración de un tratamiento oportuno.

Dengue is an endemic disease in Colombia and a large part of our population is at risk of suffering from this illness. One of the main problems in the management of dengue is the difficulty to do an appropriate and early diagnosis, because the disease presents an inespecific evolution, thus, it is essential to account on fast and effective diagnostic tools. The present work aimed to evaluate the diagnostic value of detection of the viral protein NS1 in patients with suspected acute dengue, from the Department de Cundinamarca, who had previously been submitted to IgM detection in the Cundinamarca Public Health Laboratory; 44 samples came from patients with a positive IgM test and the other 44 to patients with negative IgM for dengue virus. All serum samples were submitted to Pan Dengue Early ELISA (Panbio) system for NS1 detection. The statistical analysis showed a moderate concordance between the two diagnostic tests. We also found that 40% of positive samples for NS1 had previously been reported as negative according to the results of IgM. Simi1arly, it was found that as younger age, severe disease was present, there were found significant differences in the presence of rash, absence of diarrhea, leukocytes <4000 cel/μl and platelets <180,000/μl when comparing positive and negative results of each test. We can conclude that NS1 determination is needed in suspected cases of acute dengue, and in conjunction with the determination of IgM represents an efficient complement to diagnosis, thus expediting the implementation of early treatment.

Up-regulation of lipoxygenase, phospholipase, and oxylipin-production in the induced chemical defense of the red alga Gracilaria chilensis against epiphytes.

The red alga Gracilaria chilensis is commercially farmed for the production of agar hydrocolloids, but some susceptible algae in farms suffer from intense epiphyte growth. We investigated the induced chemical defense response of G. chilensis against epiphytes and demonstrated that an extract of an epiphyte-challenged alga can trigger a defense response. The hormonally active metabolites were purified by RP-HPLC. Treatment with the extract or the purified fraction changed the chemical profile of the alga and increased resistance against epiphyte spores. Semi-quantitative RT-PCR and enzyme assays demonstrated that this metabolic response occurs after an increase in lipoxygenase and phospholipase A2 activity. Although this suggests the involvement of regulatory oxylipins, neither jasmonic acid nor the algal metabolite prostaglandin E2 triggers comparable defense responses.

LAMINARIOCOLAX SP. (PHAEOPHYCEAE) ASSOCIATED WITH GALL DEVELOPMENTS IN LESSONIA NIGRESCENS (PHAEOPHYCEAE)(1).

As part of a long-term study on the biology and ecology of the intertidal kelp Lessonia nigrescens Bory, we report on the occurrence of gall development on this alga, identified the possible causal agent, and assessed the extent of the phenomenon in two wild stands of the host. Our results showed that galls affecting natural populations of L. nigrescens were associated with the infection by a filamentous brown algal endophyte of the genus Laminariocolax. Assignment to Laminariocolax of the endophytes isolated from cultured gall tissue was based on the (i) high internal transcribed spacer 1 (ITS1) sequence similarity and phylogenetic relationship between the Chilean isolates and several species of the genus Laminariocolax endophytic in other kelps, (ii) reproductive and vegetative features of the endophyte in culture, and (iii) anatomical agreement of fully developed galls of Lessonia with those described for other kelp galls caused by endophytic members of Laminariocolax. Unequivocal identification at the species level of the endophytes infecting Lessonia, however, awaits further studies.

Phospholipases and galactolipases trigger oxylipin-mediated wound-activated defence in the red alga Gracilaria chilensis against epiphytes.

We investigated the wound response of the commercially important red alga, Gracilaria chilensis, in order to obtain insight into its interaction with epiphytic pests. After wounding, the host releases free fatty acids as well as the hydroxylated eicosanoids, 8R-hydroxy eicosatetraenoic acid (8-HETE) and 7S,8R-dihydroxy eicosatetraenoic acid (7,8-di-HETE). While the release of free arachidonic acid and subsequent formation of 8-HETE is controlled by phospholipase A, 7,8-di-HETE production is independent of this lipase. This dihydroxylated fatty acid might be directly released from galactolipids. Physiologically relevant concentrations of oxylipins reduced spore settlement of Acrochaetium sp. (Rhodophyta, Acrochaetiaceae) and suppressed the development of hapteria in Ceramium rubrum (Rhodophyta, Ceramiaceae) when these model epiphytes were exposed to artificial surfaces that contained 8-HETE or 7,8-di-HETE. Thus, the immediate release of oxylipins can be seen as G. chilensis defence against epiphytes.