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Background Use of phytopathogenic fungi for the biocontrol of weeds represents a promising path in the search for new management alternatives that allow reducing negative effects on the environment and the generation of biotypes having resistance to herbicides. The first step in developing weed biological control programs is to determine the plants and their natural enemies with the highest affinity and potential to achieve effective biocontrol. The objective of the present study was to evaluate the phytopathogenic potential of fungal isolates on four economically important weeds including: Rumex crispus L., Digitaria horizontalis Willd, Persicaria nepalensis (Meisn.) Miyabe, and Thunbergia alata Bojer ex Sims, as a possible biocontrol agent. Results Morphological and molecular identification of nine phytopathogenic isolates of weeds was achieved, according to the sequencing of the ITS, β-Tub2, and TEF1-α regions. Pathogenicity of the following species on original hosts was confirmed: Colletotrichum cigarro, Epicoccum draconis, and Didymella rumicicola on R. crispus; Bipolaris sp., on D. horizontalis; Bipolaris zeicola, Phialemoniopsis curvata, and Stemphylium beticola on P. nepalensis and, Alternaria thunbergiae and Nigrospora sphaerica on T. alata. These could be, fairly, considered the first worldwide reports of such interactions, except for A. thunbergiae and Bipolaris sp. The most virulent interactions according to the AUDPC value corresponded to (R. crispus × D. rumicicola), (D. horizontalis × Bipolaris sp.), (P. nepalensis × S. beticola) and (T. alata × A. thunbergiae), with an incidence of 100%. Conclusion These strains were proposed for future research as potential biocontrol agents, which represented a great resource for the possible generation of new bio-herbicides.

Background Cadmium uptake by cacao plants can affect plant growth, consumer health and commercialisation. To develop mitigation strategies, it is essential to identify the soil characteristics that could influence this absorption. To determine the relationships between cadmium absorption and the soil characteristics of cacao areas, the responses at concentrations of 0, 2, 5, 10 and 20 μg g-1 of cadmium in three soils of these areas and an andisol were evaluated, using 120-day-old seedlings of four cultivars of Theobroma cacao L. Results In the present study, several relationships were found between chemical and physical soil characteristics and available cadmium, such as real and bulk densities, as well as contents of iron, sand, magnesium, potassium, sodium and copper. Additionally, moderate to strong correlations between potassium (r2 = -0.56) and real density (r2 = 0.42), with foliar cadmium, were found. Moreover, a differential deleterious effect on cacao growth in variables such as biomass was corroborated in cadmium concentrations from 5 μg g-1 in soils. There were no statistical differences between cultivars with respect to cadmium uptake or plant growth. Finally, a multiple linear regression model is proposed to estimate the foliar cadmium content (r2 = 0.878). Conclusion Some soil characteristics such as density, as well as sand, clay, aluminium, potassium and iron contents, should be considered before establishing cacao crops to avoid cadmium accumulation. The correlation between potassium with foliar cadmium indicated that potassium could be significant in cadmium uptake mitigation strategies. The high correlation between available cadmium and foliar cadmium indicates that the quantification methodology developed using ethylenediaminetetraacetic acid extractant may be a useful diagnostic tool. © 2021 Society of Chemical Industry.

At least 20–40% of annual losses of avocado crops are caused by pathogenic fungi. The chemical treatments of these diseases are inefficient, cause environmental pollution and are increasingly restricted by international laws. This work aimed to assess the biocontrol capacity of a bacterial extract to protect avocado fruits and plants from pathogen infections. Extracts from the bacterial isolate Serratia sp. ARP5.1 were obtained from liquid fermentations in a biorreactor. A body rot postharvest infection model with Colletotrichum gloeosporioides on fruits was developed. Moreover, packaging conditions were simulated using the bacterial extract and the commercial fungicide prochloraz as a positive control. Additionally, seedlings infections with Phytophthora cinnamomi were performed on two types of avocado (West Indian race and cv. Hass). The Area Under Disease Progress Curve (AUDPC) was recorded using the bacterial extract and a commercial product with fosetyl-aluminium as treatments. The bacterial extract significantly reduced infections by C. gloeosporioides on injured avocado fruits at 31.1 μg mL−1. Intact fruits were also protected against body rot infections at the same concentration and showed no significant differences with the commercial fungicide. On the other hand, AUDPC in the seedlings was significantly reduced with the extract treatment at 3 μg mL−1 compared to the control. However, a possible phytotoxicity effect of the extract was evidenced in the seedlings and confirmed by pathogen recovery and tests on Raphanus sativus seedlings. Finally, formulations of the extracts (emulsion and emulsifiable concentrate) were prepared, and bioactive stability was assessed for 8 wk. The emulsion formulates demonstrated very stable bioactivity against P. cinnamomi. The extract and the emulsion formulate showed promising results for the control of avocado pathogens. New bioproducts based on this type of active principles could be developed for the benefit of avocado industry.

Anemia caused by trypanosome infection is poorly understood. Autoimmunity during Trypanosoma brucei infection was proposed to have a role during anemia, but the mechanisms involved during this pathology have not been elucidated. In mouse models and human patients infected with malaria parasites, atypical B-cells promote anemia through the secretion of autoimmune anti-phosphatidylserine (anti-PS) antibodies that bind to uninfected erythrocytes and facilitate their clearance. Using mouse models of two trypanosome infections, Trypanosoma brucei and Trypanosoma cruzi, we assessed levels of autoantibodies and anemia. Our results indicate that acute T. brucei infection, but not T. cruzi, leads to early increased levels of plasma autoantibodies against different auto antigens tested (PS, DNA and erythrocyte lysate) and expansion of atypical B cells (ABCs) that secrete these autoantibodies. In vitro studies confirmed that a lysate of T. brucei, but not T. cruzi, could directly promote the expansion of these ABCs. PS exposure on erythrocyte plasma membrane seems to be an important contributor to anemia by delaying erythrocyte recovery since treatment with an agent that prevents binding to it (Annexin V) ameliorated anemia in T. brucei-infected mice. Analysis of the plasma of patients with human African trypanosomiasis (HAT) revealed high levels of anti-PS antibodies that correlated with anemia. Altogether these results suggest a relation between autoimmunity against PS and anemia in both mice and patients infected with T. brucei., Author summary African trypanosomes are relevant pathogens and a cause of great morbidity and economic burden in endemic countries. Anemia during infection by African Trypanosomes is one of the most common pathologies associated with the disease, but the mechanisms leading to it are poorly understood. Here, we report evidence of autoimmunity, particularly autoantibodies against the lipid phosphatidylserine that are secreted by autoimmune/atypical B-cells, in Trypanosoma brucei infected mice and that are also found in Human African Trypanosomiasis patients and correlate with levels of anemia. These findings point to a relation between autoimmunity and anemia during infection with African Trypanosomes, possibly through the secretion of autoantibodies against phosphatidylserine.

In this study, the efficiency of gaseous ozone (O3) injected in the soil as an oxidizing agent for the inactivation of F. oxysporum was evaluated under laboratory conditions. The results sh...

Severe anemia is a major cause of death by malaria. The loss of uninfected erythrocytes is an important contributor to malarial anemia; however, the mechanisms underlying this pathology are not well understood. Malaria-induced anemia is related to autoimmune antibodies against the membrane lipid phosphatidylserine (PS). In mice, these antibodies induce the clearance of uninfected erythrocytes after binding to PS exposed in their membrane. In human malaria patients, there is a strong correlation between anemia and anti-PS antibodies. During malaria, anti-PS antibodies are produced by atypical B cells, whose levels correlate with the development of anemia in patients. Autoimmune responses, which are documented frequently in different infections, contribute to the pathogenesis of malaria by inducing the clearance of uninfected erythrocytes.

Contexto: El entrenamiento militar y las actividades deportivas desarrolladas en el proceso de formación de los alumnos de la escuela de oficiales del Ejército Nacional, conllevan en sí mismo, un riesgo de lesiones musculo-esqueléticas, lo cual genera alteraciones en la salud del personal, días de incapacidad, hospitalizaciones y disminución del desempeño físico. Es por esto, que mediante el presente estudio se busca caracterizar los tipos de lesiones presentadas en un evento deportivo, mediante un sistema de clasificación más preciso, buscando a posterior, crear herramientas de vigilancia epidemiológica como mecanismo de prevención de dichas lesiones. Objetivo: Caracterizar las lesiones deportivas presentadas en los alumnos durante los Juegos Inter-compañías en la Escuela Militar de Cadetes (ESMIC), mediante el sistema de clasificación estandarizado OSICS – 10. Metodología: Estudio de tipo observacional, descriptivo con componente analítico, en el cual se realizó una recolección de datos de las lesiones presentadas en el transcurso de las competencias anuales que se llevan a cabo entre los alumnos de las diferentes compañías de la Escuela Militar de Cadetes “General José María Córdova”. Todas las lesiones fueron registradas de fuentes de información primaria, las cuales fueron evaluadas por el servicio de medicina del deporte, con posterior tabulación, consolidación y análisis mediante el uso de los formatos recomendados por el Comité Olímpico Internacional (COI) y codificadas mediante el sistema de clasificación OSICS-10. Resultados: 43 lesiones fueron registradas, con una tasa de lesión de 11.9 por 1000 atleta-día, el 67% de los afectados sufrieron lesiones en las extremidades inferiores. El tipo de lesión predominante fue el esguince con un 35% del total de las lesiones; 78% de las lesiones fueron causadas por el contacto con otro jugador y se generaron un total de 323 días de incapacidad durante el evento. Conclusión: La descripción epidemiológica, la clasificación y la codificación de las lesiones durante un evento deportivo militar, generaron registros útiles para la descripción de los escenarios de riesgo, lo que nos permite la implementación de un sistema de vigilancia epidemiológica de las lesiones deportivas.

Infectious pathogens contribute to the development of autoimmune disorders, but the mechanisms connecting these processes are incompletely understood. Here we show that Plasmodium DNA induces autoreactive responses against erythrocytes by activating a population of B cells expressing CD11c and the transcription factor T-bet, which become major producers of autoantibodies that promote malarial anaemia. Additionally, we identify parasite DNA-sensing through Toll-like receptor 9 (TLR9) along with inflammatory cytokine receptor IFN-γ receptor (IFN-γR) as essential signals that synergize to promote the development and appearance of these autoreactive T-bet+ B cells. The lack of any of these signals ameliorates malarial anaemia during infection in a mouse model. We also identify both expansion of T-bet+ B cells and production of anti-erythrocyte antibodies in ex vivo cultures of naive human peripheral blood mononuclear cells (PBMC) exposed to P. falciprum infected erythrocyte lysates. We propose that synergistic TLR9/IFN-γR activation of T-bet+ B cells is a mechanism underlying infection-induced autoimmune-like responses., Autoimmune anaemia often accompanies Plasmodium infection and malaria, but how anaemia is induced is still unclear. Here the authors show that Plasmodium DNA, together with interferon-γ, can activate B cells to induce auto-antibodies that recognize red blood cells and promote their removal to contribute to anaemia onset.

Anemia is a common complication of malaria that is characterized by the loss of infected and uninfected erythrocytes. In mouse malaria models, clearance of uninfected erythrocytes is promoted by autoimmune anti-phosphatidylserine (PS) antibodies produced by T-bet+B-cells, which bind to exposed PS in erythrocytes, but the mechanism in patients is still unclear. In Plasmodium falciparum patients with anemia, we show that atypical memory FcRL5+T-bet+ B-cells are expanded and associate both with higher levels of anti-PS antibodies in plasma and with the development of anemia in these patients. No association of anti-PS antibodies or anemia with other B-cell subsets and no association of other antibody specificities with FcRL5+T-bet+ B-cells is observed, revealing high specificity in this response. We also identify FcRL5+T-bet+ B-cells as producers of anti-PS antibodies in ex vivo cultures of naïve human peripheral blood mononuclear cells (PBMC) stimulated with P.-falciparum-infected erythrocyte lysates. These data define a crucial role for atypical memory B-cells and anti-PS autoantibodies in human malarial anemia.

Zika virus infection is associated with the development of Guillain-Barré syndrome (GBS), a neurological autoimmune disorder caused by immune recognition of gangliosides and other components at nerve membranes. Using a high-throughput ELISA, we have analyzed the anti-glycolipid antibody profile, including gangliosides, of plasma samples from patients with Zika infections associated or not with GBS in Salvador, Brazil. We have observed that Zika patients that develop GBS present higher levels of anti-ganglioside antibodies when compared to Zika patients without GBS. We also observed that a broad repertoire of gangliosides was targeted by both IgM and IgG anti-self antibodies in these patients. Since Zika virus infects neurons, which contain membrane gangliosides, antigen presentation of these infected cells may trigger the observed autoimmune anti-ganglioside antibodies suggesting direct infection-induced autoantibodies as a cause leading to GBS development. Collectively, our results establish a link between anti-ganglioside antibodies and Zika-associated GBS in patients., Author summary Zika virus infection can trigger the development of Guillain Barré syndrome (GBS), a neurological autoimmune disorder mediated by antibodies recognizing gangliosides in nerve membranes. Mechanisms such as molecular mimicry have been identified as a cause for GBS development in certain infections, such as Campylobacter jejuni, but the broad self reactivity observed during GBS suggests a role for alternative mechanisms. Our finding that Zika patients with GBS present higher levels of anti-ganglioside antibodies compared to uncomplicated Zika patients in Brazil points to these auto-antibodies as a trigger for GBS in these patients. These findings further support infection-induced autoantibodies as a factor contributing to GBS development, adding novel mechanisms for GBS development beyond molecular mimicry.

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.

Malaria caused by Plasmodium vivax is a highly prevalent infection world-wide, that was previously considered mild, but complications such as anemia have been highly reported in the past years. In mice models of malaria, anti-phosphatidylserine (anti-PS) autoantibodies, produced by atypical B-cells, bind to uninfected erythrocytes and contribute to anemia. In human patients with P. falciparum malaria, the levels of anti-PS, atypical B-cells and anemia are strongly correlated to each other. In this study, we focused on assessing the relationship between autoantibodies, different B-cell populations and hemoglobin levels in two different cohorts of P. vivax patients from Colombia, South America. In a first longitudinal cohort, our results show a strong inverse correlation between different IgG autoantibodies tested (anti-PS, anti-DNA and anti-erythrocyte) and atypical memory B-cells (atMBCs) with hemoglobin in both P. vivax and P. falciparum patients over time. In a second cross-sectional cohort, we observed a stronger relation between hemoglobin levels, atMBCs and autoantibodies in complicated P. vivax patients compared to uncomplicated ones. Altogether, these data constitute the first evidence of autoimmunity associating with anemia and complicated P. vivax infections, suggesting a role for its etiology through the expansion of autoantibody-secreting atMBCs., Author summary Malaria is one of the top global infections causing high mortality and morbidity every year. Plasmodium vivax is the most prevalent malarial infection, particularly in the region of the Americas. Complications associated with P. vivax, such as anemia, are a growing reported phenomenon, but the mechanisms leading to them are poorly understood. Here, we report the first evidence of autoantibodies and Atypical Memory B-cells correlating with anemia in two different cohorts of P. vivax patients, particularly during complicated infections. These findings point to Atypical Memory B-cells as key pathological players, possibly through the secretion of autoantibodies, and attributes a role for autoimmunity in mediating complications during P. vivax infections.

Zika virus (ZIKV) disease has become a global health emergency with devastating effects on public health. Recent evidences implicate the virus as an emergent neuropathological agent promoting serious pathologies of the human nervous system, that include destructive and malformation consequences such as development of ocular and fetal brain lesions, microcephaly in neonates, and Guillain–Barré syndrome (GBS) in adults. These neurological disorders of both central and peripheral nervous systems are thought to be associated to the neurotropic properties of the virus that has ability to infect neural stem cells as well as peripheral neurons, a hallmark of its pathogenicity. The presence of autoantibodies against gangliosides plays a pivotal role in the etiogenesis of GBS and a variety of neurological disorders. Gangliosides are a class of galactose-containing cerebrosides mainly expressed in nervous system tissues playing a critical role in the physiology of neural cells and neurogenesis. Herein, our findings indicate that patients at acute phase of ZIKV infection without any neurological signs show increased levels of IgG autoantibody against GD3 gangliosides, a class of glycolipid found to be highly expressed in neural stem cell acting in the maintenance of their self-renewal cellular capacity. It is possible that a pathological threshold of these antibodies is only acquired in secondary or subsequent infections. In the light of these evidences, we propose that the target of GD3 by autoimmune responses may possibly has an effect in the neuropathy and neurogenesis disorder seen during ZIKV infection.

Anti-self antibodies are most commonly associated with auto-immune disorders, but a large body of evidence indicates that they are also present in numerous infectious diseases. These autoimmune antibodies appear transiently during infection with a number of viruses, bacteria and parasites, and in some cases, have been associated with the development of auto-immune disorders that develop after infection has been cleared. Traditionally these infection-associated auto-antibodies are considered an erroneous byproduct of a legitimate immune response, but their possible role in the clearance of microbes and infected cells or inhibition of host-cell invasion suggests that they may be present because of their beneficial protective role against different infections.

In this work Linear Low Density Polyethylene-nonwoven industrial Fique fiber mat (LLDPE-Fique) and Epoxy Resin-nonwoven industrial Fique fiber mat (EP-Fique) biocomposites were prepared using thermocompression and resin film infusion processes. Neat polymeric matrices and its biocomposites were tested following ASTM standards in order to evaluate tensile and flexural mechanical properties. Also, thermal behavior of these materials has been studied by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Tensile and flexural test revealed that nonwoven Fique reinforced composites exhibited higher modulus and strength but lower deformation capability as compared with LLDPE and EP neat matrices. TG thermograms showed that nonwoven Fique fibers incorporation has an effect on the thermal stability of the composites. On the other hand, Fique fibers did not change the crystallization and melting processes of the LLDPE matrix but restricts the motion of EP macromolecules chains thus increases the Tg of the EP-Fique composite. Finally, this work opens the possibility of considering non-woven Fique fibers as a reinforcement material with a high potential for the manufacture of biocomposites for automotive applications. In addition to the processing test specimens, it was also possible to manufacture a part of LLDPE-Fique, and one part of EP-Fique. Keywords: Biocomposites, Natural materials, Nonwoven Fique fiber mat, LLDPE, Epoxy Resin

Extreme reduction in cellular water content leads to desiccation, which, if persistent, affects the physiology of organisms, mainly through oxidative stress. Some organisms are highly tolerant to desiccation, including resurrection plants and certain intertidal seaweeds. One such species is Pyropia orbicularis, a rhodophycean that colonizes upper intertidal zones along the Chilean coast. Despite long, daily periods of air exposure due to tides, this alga is highly tolerant to desiccation. The present study examined the proteome of P. orbicularis by 2DE and LC-MS/MS analyses to determine the proteins associated with desiccation tolerance (DT). The results showed that, under natural conditions, there were significant changes in the protein profile during low tide as compared to naturally hydrated plants at high tide. These changes were mainly in newly appeared proteins spots such as chaperones, monodehydroascorbate reductase, and manganese superoxide dismutase, among others. Previously undescribed proteins under desiccation conditions included phycobiliproteins, glyoxalase I, and phosphomannomutase. These changes evidenced that several physiological responses involved in DT are activated during low tide, including decreased photosynthetic activity, increased antioxidant capacity, and the preservation of cell physiology by regulating water content, cell wall structure, and cell volume. Similar responses have been observed in resurrection plants and bryophytes exposed to desiccation. Therefore, the coordinated activation of different desiccation tolerance pathways in P. orbicularis could explain the successful biological performance of this seaweed in the upper intertidal rocky zones.

ResumenAlgunas especies de peces marinos tienen complejas relaciones con los ecosistemas costeros durante sus periodos reproductivos, tal es el caso del pez aguja Tylosurus pacificus, que conforma agregaciones de desove en playas de grava en el Parque Nacional Natural Utría. Se describe la actividad pesquera y algunos aspectos de la biología reproductiva de T. pacificus y se proponen algunas medidas para mitigar el impacto sobre este evento y los procesos ecológicos asociados. Se realizó un monitoreo pesquero entre abril 2008 y febrero 2009 en el Parque Nacional Natural Utría (PNNU), Pacífico colombiano. Se analizaron los volúmenes de captura, estructura por talla, proporción de sexos y fecundidad (n= 84). La longitud total osciló entre 60.5 cm y 104 cm con una media y desviación estándar de 85.35 ± 9.09 cm. La fecundidad promedio fue 189 685.56 ovocitos por gónada, con una moda de 8 mm de diámetro y un desarrollo gonadal asincrónico. La especie desova en forma colectiva en la playa cuando la marea alcanza el nivel más alto durante la luna llena y nueva, generalmente al anochecer. Pescadores que habitan los pueblos cercanos aprovechan este recurso, durante la agregación reproductiva de la especie. Es importante ampliar el estudio de la reproducción de T. pacificus y los procesos ecológicos asociados a su desove para poder dar un aprovechamiento adecuado y garantizar la sostenibilidad de su pesquería a largo plazo. Abstract:Some species of marine fish have complex relationships with coastal ecosystems during their reproductive periods, as the needle fish Tylosurus pacificus that forms spawning aggregations in gravel beaches in Utría Park. We described fishery and some aspects of the reproductive biology of T. pacificus and proposed some strategies to mitigate the impact of this event and associated ecological processes. Fisheries monitoring were conducted between April 2008 and February 2009 in the Utría National Park, Colombian Pacific. Catch volumes, length structure, sex ratio and fecundity (n= 84) were analyzed. The total length ranged among 60.5 and 104 cm with a mean and standard deviation of 85.35 ± 9.09 cm. The average fertility of oocytes per gonad was 189 685.56, with a mode of 8 mm diameter and an asynchronous gonadal development. This species spawns collectively on the beach when the tide reaches the highest level during full and new moon, usually in the evening. Fishermen of a near town take advantage of the spawning aggregation of this species. The reproduction study of T. pacificus and ecological processes associated with their spawning, should be expanded to give adequate use, and ensure the sustainability of their fishery over the long term. Rev. Biol. Trop. 65 (1): 77-87. Epub 2017 March 01.

Malaria is one of the most life-threatening infectious diseases worldwide. Immunity to malaria is slow and short-lived despite the repeated parasite exposure in endemic areas. Malaria parasites have evolved refined machinery to evade the immune system based on a range of genetic changes that include allelic variation, biomolecular exposure of proteins, and intracellular replication. All of these features increase the probability of survival in both mosquitoes and the vertebrate host. Plasmodium species escape from the first immunological trap in its invertebrate vector host, the Anopheles mosquitoes. The parasites have to pass through various immunological barriers within the mosquito such as anti-microbial molecules and the mosquito microbiota in order to achieve successful transmission to the vertebrate host. Within these hosts, Plasmodium species employ various immune evasion strategies during different life cycle stages. Parasite persistence against the vertebrate immune response depends on the balance among virulence factors, pathology, metabolic cost of the host immune response, and the parasites ability to evade the immune response. In this review we discuss the strategies that Plasmodium parasites use to avoid the vertebrate host immune system and how they promote successful infection and transmission.

International audience; Associated microbiota play crucial roles in health and disease of higher organisms. For macroalgae, some associated bacteria exert beneficial effects on nutrition, morphogenesis and growth. However, current knowledge on macroalgae–microbiota interactions is mostly based on studies on green and red seaweeds. In this study, we report that when cultured under axenic conditions, the filamentous brown algal model Ectocarpus sp. loses its branched morphology and grows with a small ball-like appearance. Nine strains of periphytic bacteria isolated from Ectocarpus sp. unialgal cultures were identified by 16S rRNA sequencing, and assessed for their effect on morphology, reproduction and the metabolites secreted by axenic Ectocarpus sp. Six of these isolates restored morphology and reproduction features of axenic Ectocarpus sp. Bacteria-algae co-culture supernatants, but not the supernatant of the corresponding bacterium growing alone, also recovered morphology and reproduction of the alga. Furthermore, colonization of axenic Ectocarpus sp. with a single bacterial isolate impacted significantly the metabolites released by the alga. These results show that the branched typical morphology and the individuals produced by Ectocarpus sp. are strongly dependent on the presence of bacteria, while the bacterial effect on the algal exometabolome profile reflects the impact of bacteria on the whole physiology of this alga.

Plasmodium species, the parasitic agents of malaria, invade erythrocytes to reproduce, resulting in erythrocyte loss. However, a greater loss is caused by the elimination of uninfected erythrocytes, sometimes long after infection has been cleared. Using a mouse model, we found that Plasmodium infection induces the generation of anti-self antibodies that bind to the surface of uninfected erythrocytes from infected, but not uninfected, mice. These antibodies recognize phosphatidylserine, which is exposed on the surface of a fraction of uninfected erythrocytes during malaria. We find that phosphatidylserine-exposing erythrocytes are reticulocytes expressing high levels of CD47, a "do-not-eat-me" signal, but the binding of anti-phosphatidylserine antibodies mediates their phagocytosis, contributing to anemia. In human patients with late postmalarial anemia, we found a strong inverse correlation between the levels of anti-phosphatidylserine antibodies and plasma hemoglobin, suggesting a similar role in humans. Inhibition of this pathway may be exploited for treating malarial anemia.

The kelp Lessonia nigrescens Bory is the most ecologically and economically important seaweed in rocky intertidal and shallow subtidal habitats along the temperate Pacific South American coasts. Recent molecular studies suggest the existence of two lineages, one (northern lineage) from 17° S to 30° S and a second (central lineage) from 29° S to 41° S. To identify and name these lineages we performed morphological, nomenclatural and field studies. Four external and three internal anatomical traits permitted a morphological separation of the two lineages. The internal structure of both lineages was different from the isolectotype of Lessonia nigrescens. It is therefore concluded that the name Lessonia nigrescens should not be used for the Chilean material. Chordaria spicata Suhr appears as the oldest available name for the central lineage, while Lessonia berteroana Montagne is the oldest name for the northern lineage. In both cases, the type material consisted of small-sized, apical branches of larger plants. The new combination Lessonia spicata (Suhr) Santelices is proposed for the central lineage and we reinstate Lessonia berteroana for the northern lineage. Laminaria scissa Suhr is reduced to synonym of L. spicata. Representative specimens of Lessonia nigrescens were not found during new visits to its type locality in Cape Horn and along Chile. Future studies should verify the status of this species.

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.

Little is known about variation of sex ratio, the proportion of males to females, in natural populations of seaweed, though it is a major determinant of the mating system. The observation of sexual chromosomes in kelps suggested that sex is partly genetically determined. However, it is probably not purely genetic since the sex ratio can be modified by environmental factors such as salinity or temperature. In this paper, sex ratio variation was studied in the kelp Lessonia nigrescens Bory complex, recently identified as two cryptic species occurring along the Chilean coast: one located north and the other south of the biogeographic boundary at latitude 29°-30° S. The life cycle of L. nigrescens is characterized by an alternation of microscopic haploid gametophytic individuals and large macroscopic fronds of diploid sporophytes. The sex ratio was recorded in progenies from 241 sporophytic individuals collected from 13 populations distributed along the Chilean coast in order (i) to examine the effect of an environmental gradient coupled with latitude, and (ii) to compare marginal populations to central populations of the two species. In addition, we tested the hypothesis that the sex ratios of the two cryptic species would be affected differently by temperature. First, our results demonstrate that sex ratio seems to be mainly genetically determined and temperature can significantly modify it. Populations of the northern species showed a lower frequency of males at 14°C than at 10°C, whereas populations of the southern species showed the opposite pattern. Second, both species displayed an increased variation in sex ratio at the range limits. This greater variation at the margins could be due either to differential mortality between sexes or to geographic parthenogenesis (asexual reproduction).

Unravelling the mechanisms underlying desiccation tolerance is crucial in order to understand the position of algal species in the intertidal zone. The alga Porphyra columbina lives in the uppermost part of the rocky intertidal zones around the world and was selected as a model for this study. Naturally desiccated plants were collected during low tide and studied for morphological changes, oxidative burst induction, biomolecule oxidation, antioxidant responses, and photosynthetic status. Naturally hydrated plants collected during high tides were used for comparative purposes. In addition, changes induced by desiccation were assessed in vitro and the capacity to recover from desiccation was determined by rehydrating the fronds in seawater. The global results show that desiccation induces morphological and cellular alterations accompanied by a loss of ∼96% of the water content. Overproduction of reactive oxygen species (ROS) was induced by desiccation and two peaks of H(2)O(2) were detected at 1 and 3 h of desiccation. However, during in vitro rehydration post-desiccation, the ROS quickly returned to the basal levels. At the biomolecular level, only a low production of oxidized proteins was recorded during desiccation, whereas the activity of diverse antioxidant enzymes increased. However, this activity diminished to near basal levels during rehydration. The photosynthetic efficiency (F(v)/F(m)) during desiccation declined by 94-96% of the values recorded in hydrated plants. This reduction was generated by the low levels of trapped energy flux per cross-section (TRo/CS), electron transport flux per CS (ETo/CS), and density of reaction centres (RC/SCo) as well as the chlorophyll content. The inverse pattern was observed for the levels of phycocyanin and phycoerythrin content. F(v)/F(m) and the photosynthetic indicators were restored to normal levels after only 5 min of rehydration. The results indicate that desiccation in P. columbina causes overproduction of ROS that is efficiently attenuated. The morphological and photosynthetic changes could be operating as tolerance mechanisms due to the fact that these responses principally prevent biomolecular alteration and cellular collapse. Thus, the activation of different physiological mechanisms helps to explain the high tolerance to desiccation of P. columbina and, at least in part, the position of this species at the highest level in the intertidal zone.

Combined phylogenetic, physiological, and biochemical approaches revealed that differences in defense-related responses among 17 species belonging to the Gracilariaceae were consistent with their evolutionary history. An oxidative burst response resulting from activation of NADPH oxidase was always observed in two of the subgenera of Gracilaria sensu lato (Gracilaria, Hydropuntia), but not in Gracilariopsis and in species related to Gracilaria chilensis (“chilensis” clade). On the other hand, all species examined except Gracilaria tenuistipitata var. liui and Gracilariopsis longissima responded with up-regulation of agar oligosaccharide oxidase to an challenge with agar oligosaccharides. As indicated by pharmacological experiments conducted with Gracilaria chilensis and Gracilaria sp. “dura,” the up-regulation of agar oligosaccharide oxidase involved an NAD(P)H-dependent signaling pathway, but not kinase activity. By contrast, the activation of NADPH oxidase requires protein phosphorylation. Both responses are therefore independent, and the agar oligosaccharide-activated oxidative burst evolved after the capacity to oxidize agar oligosaccharide, probably providing additional defensive capacity to the most recently differentiated clades of Gracilariaceae. As demonstrated with Gracilaria gracilis, Gracilaria dura, and Gracilariopsis longissima, the different responses to agar oligosaccharides allow for a fast and nondestructive distinction among different clades of gracilarioids that are morphologically convergent. Based upon sequences of the chloroplast-encoded rbcL gene, this study suggests that at least some of the samples from NW America recorded as Gs. lemanaeiformis are probably Gs. chorda. Moreover, previous records of Gracilaria conferta from Israel are shown to be based upon misidentification of Gracilaria sp. “dura,” a species that belongs to the Hydropuntia subgenus.

In order to analyse copper-induced calcium release and (reactive oxygen species) ROS accumulation and their role in antioxidant and defense enzymes activation, the marine alga Ulva compressa was exposed to 10 µM copper for 7 d. The level of calcium, extracellular hydrogen peroxide (eHP), intracellular hydrogen peroxide (iHP) and superoxide anions (SA) as well as the activities of ascorbate peroxidase (AP), glutathione reductase (GR), glutathione-S-transferase (GST), phenylalanine ammonia lyase (PAL) and lipoxygenase (LOX) were determined. Calcium release showed a triphasic pattern with peaks at 2, 3 and 12 h. The second peak was coincident with increases in eHP and iHP and the third peak with the second increase of iHP. A delayed wave of SA occurred after day 3 and was not accompanied by calcium release. The accumulation of iHP and SA was mainly inhibited by organellar electron transport chains inhibitors (OETCI), whereas calcium release was inhibited by ryanodine. AP activation ceased almost completely after the use of OETCI. On the other hand, GR and GST activities were partially inhibited, whereas defense enzymes were not inhibited. In contrast, PAL and LOX were inhibited by ryanodine, whereas AP was not inhibited. Thus, copper stress induces calcium release and organellar ROS accumulation that determine the differential activation of antioxidant and defense enzymes.

International audience; The origin of the Ectocarpus strain used for genome sequencing (the ‘genome strain’) was Peru, where no Ectocarpus had been reported previously. To study the genetic diversity in the region and to increase the number of individuals from this area available for genetic experiments, 119 new Ectocarpus strains were isolated from eight localities along the 3000 km of coastline from central Peru to central Chile.Internal transcribed spacer 1 (ITS1) genotyping revealed nine different genotypes, five of which were endemic to the area studied and three of which were previously unknown.Individuals of the same genotype as the genome strain occurred from Peru to northernmost Chile, representing 61% of the samples in this area, from which five more genotypes were isolated. Further south, down to central Chile, most individuals belonged to Ectocarpus siliculosus, Ectocarpus fasciculatus and Ectocarpus crouaniorum. In sexual crosses, the genome strain and the new isolates of the same genotype were fully compatible.Sequences from four nuclear and cytoplasmic genetic markers (ITS1, ITS2, Rubisco spacer and Cytochrome‐c oxidase subunit 3 (cox3)) separated the genome strain from the known species of Ectocarpus. It may in future be recognized as a separate species.

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.

In order to help explain the absence of the brown kelp Lessonia nigrescens from a coastal environment chronically enriched with copper, we characterized the biochemical responses induced by copper stress in this kelp and compared them with those displayed by the copper tolerant brown alga Scytosiphon lomentaria. These algae were cultivated with increasing concentrations of copper (20, 40 and 100microgL(-1)) for 96h and the temporal production of hydrogen peroxide, superoxide anions and lipoperoxides as well as the activities of antioxidant enzymes catalase (CAT), glutathione peroxidase (GP), ascorbate peroxidase (AP), dehydroascorbate reductase (DHAR) and glutathione reductase (GR) and the activity of the defense enzyme lipoxygenase (LOX) were determined. In L. nigrescens and S. lomentaria, a single peak of hydrogen peroxide was detected, with similar maxima after 3h of copper exposure, although in L. nigrescens buffering took longer. Superoxide anions, on the other hand, were only detected in L. nigrescens. The production of lipoperoxides in L. nigrescens increased steadily at higher copper levels, in a pattern clearly different to their rapid stabilization in S. lomentaria. We suggest that the accumulation of lipoperoxides might be related to LOX, whose activity also increases with exposure time. Furthermore, activities of the antioxidant enzymes CAT, GP, AP and DHAR were lower in L. nigrescens than in S. lomentaria, and GP and DHAR were completely inhibited at higher copper concentrations. Since these enzymes also detoxify fatty acid hydroperoxides, their inhibition, together with the activation of LOX, may explain the persistent and copper-dependent levels of lipoperoxides in L. nigrescens. Based on terrestrial plant models demonstrating toxic effects of lipoperoxides, and on our results on organellar ultrastructural changes, we suggest that copper toxicity induced an uncontrolled lipoperoxide accumulation which may lead to cell damage and dysfunction in L. nigrescens, explaining at least partially, the absence of this kelp in a copper-enriched coastal environment.

In addition to the resistance to Phytophthora infestans (Rpi) genes Rpi-blb1 and Rpi-blb2, Solanum bulbocastanum appears to harbor Rpi-blb3 located at a major late blight resistance locus on LG IV, which also harbors Rpi-abpt, R2, R2-like, and Rpi-mcd1 in other Solanum spp. Here, we report the cloning and functional analyses of four Rpi genes, using a map-based cloning approach, allele-mining strategy, Gateway technology, and transient complementation assays in Nicotiana benthamiana. Rpi-blb3, Rpi-abpt, R2, and R2-like contain all signature sequences characteristic of leucine zipper nucleotide binding site leucine-rich repeat (LZ-NBS-LRR) proteins, and share amino-acid sequences 34.9% similar to RPP13 from Arabidopsis thaliana. The LRR domains of all four Rpi proteins are highly homologous whereas LZ and NBS domains are more polymorphic, those of R2 being the most divergent. Clear blocks of sequence affiliation between the four functional resistance proteins and those encoded by additional Rpi-blb3 gene homologs suggest exchange of LZ, NBS, and LRR domains, underlining the modular nature of these proteins. All four Rpi genes recognize the recently identified RXLR effector PiAVR2.

The performance of Octopus bimaculoides juveniles from coastal areas of Baja California (Mexico) and reared in captivity was evaluated using Artemia salina as food source in three different treatments: Artemia enriched with either AlgaMac or Spirulina maxima and without enrichment. After 20 days, significant differences were found among treatments in terms of growth, which was significantly higher for juvenile fed AlgaMac-enriched Artemia, followed by those fed unenriched Artemia. Moreover, far higher growth rates (0.74–0.88 mg day− 1) were obtained than those reported for other octopus species of the same size. Digestive enzyme activity during the experimental period (20 days) showed an oscillatory behavior, with a tendency to stabilize after day 15. Trypsin was the most important protease, though lipases and amylases were also present. The whole-body lipid content of the juvenile was apparently influenced by the lipid content in the food. The amino acid profile remained unaffected after juvenile were fed the different treatments; however, differences were found between the initial and final whole-body content of the juvenile, with relatively lower amounts of isoleucine, leucine and tyrosine, and relatively higher amounts of threonine, alanine and glycine after 20 days of feeding. The Artemia amino acid content of phenylalanine, isoleucine, leucine and valine was limited, and growth would likely be further promoted with a more suitable diet. Thus, O. bimaculoides is a promising species for commercial culture, and even though good results were obtained when fed Artemia, a more appropriate food source should be sought to obtain an amino acid profile that will maximize growth.

To better understand the toxicity and the orchestration of antioxidant defenses of marine brown algae in response to copper-induced stress, lipid peroxidation processes were investigated in the brown alga Laminaria digitata. The expression of genes involved in cell protection and anti-oxidant responses were monitored by semi-quantitative reverse transcriptase polymerase chain reaction and the lipid peroxidation products were further characterized by profiling oxylipin signatures using high-pressure liquid chromatography-mass spectrometry. Exposure to copper excess triggers lipoperoxide accumulation and upregulates the expression of stress related genes. It also increases the release of free polyunsaturated fatty acids, leading to an oxidative cascade through at least two distinct mechanisms. Incubations in presence of inhibitors of lipoxygenases and cycloxygenases showed that in addition to the reactive oxygen species-mediated processes, copper stress induces the synthesis of oxylipins through enzymatic mechanisms. Among complex oxylipins, cyclopentenones from C18 and C20 fatty acids such as 12-oxo-PDA and prostaglandins were detected for the first time in brown algae, as well as unique compounds such as the 18-hydroxy-17-oxo-eicosatetraenoic acid. These results suggest that lipid peroxidation participates in the toxic effects of copper and that lipid peroxidation derivatives may regulate protective mechanisms by employing plant-like octadecanoid signals but also eicosanoid oxylipins which are absent in vascular plants.

The growth rate of abalone post larvae of Haliotis rufescens fed ad libitum with a benthic monoalgal diatom culture maintained as monocultures on a semi-commercial scale, was evaluated and correlated with the biochemical composition of the diatoms. The cell size (7.0 × 4.0 µm to 21.0 × 7.5 µm), protein percentage (7.42% to 13.66%), and ash content (49.03% to 59.61%) were different among diatom strains; lipid percentage, nitrogen free extract, and energy content (Kcal g−1) were similar among diatom strains. The values of essential and non-essential amino and fatty acids composition differed among diatom strains. Differences in the abalone shell length and orthogonal analyses revealed postlarval growth was dependent on the quality of the food source. Postlarvae abalone displaying the longest shell lengths were fed Nitzschia thermalis var. minor and Amphiprora paludosa var. hyalina (1,712.0 ± 61 µm and 1,709 ± 67 µm, respectively), followed by Navicula incerta (1,413.3 ± 43 µm). The fatty acid content of benthic diatoms and abalone growth rate were not correlated.

High-quality protein extracts are required for proteomic studies, a field that is poorly developed for marine macroalgae. A reliable phenol extraction protocol using Scytosiphon gracilis Kogame and Ectocarpus siliculosus (Dillwyn) Lyngb. (Phaeophyceae) as algal models resulted in high-quality protein extracts. The performance of the new protocol was tested against four methods available for vascular plants and a seaweed. The protocol, which includes an initial step to remove salts from the algal tissues, allowed the use of highly resolving two-dimensional gel electrophoresis (2-DE) protein analyses, providing the opportunity to unravel potentially novel physiological processes unique to this group of marine organisms.

The extent of changes in genetic diversity and life-history traits associated with farming was investigated in the haploid-diploid red alga, Gracilaria chilensis, cultivated in Chile. This alga belongs to one of the most frequently cultivated seaweed genera around the world. Fifteen farmed populations, 11 wild populations, and two subspontaneous populations were sampled along the Chilean coast. The frequency of reproductive versus vegetative individuals and of haploid versus diploid individuals was checked in each population. In addition, the distribution of genetic variation in wild and cultivated populations was analyzed using six microsatellite markers. Our results first demonstrated that farmed populations are maintained almost exclusively by vegetative propagation. Moreover, the predominance of diploid individuals in farms showed that farming practices had significantly modified life-history traits as compared to wild populations. Second, the expected reduction in genetic diversity due to a cultivation bottleneck and subsequent clonal propagation was detected in farms. Finally, our study suggested that cultural practices in the southern part of the country contributed to the spread of selected genotypes at a local scale. Altogether, these results document for the first time that involuntary selection could operate during the first step of domestication in a marine plant.

Objective. We examined asthma risk factors among 274 Puerto Rican children born in New York to atopic mothers. Methods. We prospectively followed the cohort to measure aeroallergens in their homes and assess allergic sensitization. Baseline data are presented. Results. Maternal smoking was significantly higher among women born on the continental United States (25%) vs. those born elsewhere (11%). Cat ownership was more frequent among mainland-born women (15%) compared with those born in Puerto Rico (4%). While some aeroallergens were prevalent, few dust samples contained detectable dust mite allergens. Conclusions. By following this cohort, we hope to identify the roles that socio-cultural factors play in the process of allergic sensitization.

Parthenogenesis, the development of female gametes without fertilization, is relatively common in brown algae, although limited quantitative information on the phenomenon is available. Its occurrence is reported for the first time in Lessonia nigrescens Bory, a member of the Laminariales and a key ecological component of the benthic algal communities along the Chilean coast. Isolated female gametophytes developed into parthenosporophytes throughout the year, with a maximum in spring to early summer. Isolated male gametophytes, on the other hand, never developed fronds. Parthenosporophytes obtained in the laboratory developed normally when cultivated under greenhouse conditions, and the resulting individuals were indistinguishable in size, shape, texture, and color from heterozygous sporophytes. Quantification of DNA of various tissues demonstrated that early during their development, parthenosporophytes duplicated their DNA content, displaying levels similar to heterozygous sporophytes and almost twice the level found in gametophytes. One out of 45 individuals from a field population yielded only female gametophytes, strongly suggesting that parthenogenesis does occur in wild stands of L. nigrescens.

The taxonomic status of an alga with complanate thalli, occurring in central Chile and belonging to the genus Scytosiphon, was elucidated. Morphological and molecular features demonstrated that, in addition to the known and widespread constricted S. lomentaria (Lyngb.) Link that occurs along the Chilean coast, there is a Scytosiphon with complanate thalli that occurs only in central Chile—S. gracilis Kogame. Morphological analyses of this previously unreported complanate Scytosiphon showed thalli without constrictions, coherent plurilocular sporangia without ascocysts, and phaeophycean hairs arising from cortical cells. Furthermore, sequences of the internal transcribed spacer (ITS1 and ITS2) regions of the complanate Scytosiphon were 99.8% and 100% identical to those detected in S. gracilis from Korea. ITS-based comparative analyses showed that complanate Scytosiphon grouped in a different clade than S. lomentaria and S. tenellus Kogame from various parts of the world, including Chilean species. Moreover, molecular analyses suggest the occurrence of two distinct ITS types of S. lomentaria in northern Chile, corresponding to the Korean and Greek types. On the other hand, biochemical analyses of copper-induced antioxidant responses in S. gracilis and S. lomentaria showed an identical increase in antioxidant enzyme activities. These results suggest that copper tolerance might be a constitutive trait in these species of Scytosiphon.

The facultative red algal epiphyte Acrochaetium sp. liberated spores preferentially and recruited more successfully in laboratory cultures when its host Gracilaria chilensis C. J. Bird, McLachlan et E. C. Oliveira was present. The same effect was also induced by cell-free medium from G. chilensis, suggesting it contained a molecular signal. Antibiotics prevented spore release in Acrochaetium sp., even when G. chilensis was present, suggesting a prokaryotic origin of the signal. Simultaneous application of N-butyl-homoserine-lactone (BHL) restored the spore-release capacity, which demonstrated that spore release was not directly inhibited by the antibiotics and indicated that bacterially generated N-acyl-homoserine-lactones (AHLs) regulate spore release. An involvement of AHL was further indicated by the fact that two different halofuranone inhibitors of AHL receptors also inhibited spore release when they were applied at relatively low concentrations. Of seven different AHLs tested, only BHL induced the effect. However, BHL was only active at relatively high concentrations (100 μM), and it was not detected in spore-release-inducing medium of G. chilensis. Another water-soluble AHL or an AHL structure analog is therefore probably the active compound in G. chilensis cultures. The data presented demonstrate that life cycle completion in Acrochaetium sp. strongly depends on bacteria, which are not always present in sufficient numbers on the alga itself. Exogenous bacteria that are associated with G. chilensis or with other potential substrates may therefore trigger timely spore liberation in Acrochaetium sp., provided that the necessary concentration of AHL is reached. This first finding of AHL perception in a red alga confirms that AHL signalling is more widespread among eukaryotes than was thought until recently. However, spore release of a second red alga, Sahlingia subintegra (Rosenv.) Kornmann, was unaffected by AHL, and the reaction observed is therefore not universal.

The carrageenophytic red alga Gigartina skottsbergii presents several biological constraints for its cultivation such as restricted temporal availability and high spore mortalities that affect the development of its mass cultivation. For this reason, research to develop alternative propagation methods has been undertaken. Previous laboratory studies demonstrated that manipulating temperature, light and nutrients could enhance healing and regeneration of this seaweed. In this study nursery and field experiments were undertaken to establish the possibility to regrow G. skottsbergii in conditions similar to those applied in mass cultivation practices. Frond fragments and rhizoids were tested as alternative ways to obtain new plants. Our results indicate that regeneration occurs in the field, and can be managed in nursery conditions. The addition of a nitrogen source enhances the growth from 0.6 to 1.0% d − 1 of the healed fragments and the use of a photon flux density above 50 μmol m − 2 s − 1 increases the growth rate but decrease the survival of the explants. Explants can be transferred to field conditions and grow at similar rates to those registered in the nursery (0.5% d − 1 ). It is also possible to propagate rhizoids of G. skottsbergii and it seems that the attachment of a frond portion to the substratum, enhanced its survival and regeneration capacity. Finally, this study demonstrated that rhizoids attached to rocks can regenerate complete plants in nature, a feature which could be a useful for developing a sustainable harvesting methodology.

Juvenile individuals of the brown kelp Lessonia nigrescens were exposed to a coastal environment chronically impacted by copper mine wastes and currently displaying more than 250 nM of total dissolved copper. The kinetic of copper accumulation in the intra and extracellular compartments was determined and correlated to the oxidative burst resulting from copper-mediated oxidative stress. Accumulation involved an initial adsorption onto the outer cell wall followed by a slower uptake into the cells. A linear pattern of copper uptake over time was found during the first 52 h of exposure, and a steady state was reached at 76 h. The resulting oxidative stress was found to be inefficiently attenuated, and the intracellular level of copper remained sufficiently high to determine a persistently higher than normal level of reactive oxygen species (ROS). Thus, our results strongly suggest that, in L. nigrescens, copper needs to reach an intracellular threshold before oxidative burst develops. Furthermore, it was found that the high ROS levels generated by copper accumulation within the cells persists after the oxidative burst has ceased, suggesting a limited capacity of the algal tissue to buffer the increases of ROS caused by the environmental copper levels.

Potential for addressing ecological and physiological issues becomes severely limited when the organisms required to experimentally test specific hypotheses are absent from the study areas. This report describes a simple and inexpensive device for re-planting kelps into the lower intertidal zone of wave-swept rocky habitats, using Lessonia nigrescens Bory as a model organism. The device allows a wide range of plant sizes to be anchored by the holdfast. Transplanted kelps regenerated, re-attached to the substratum and overgrew the transplanting device. These results confirm the feasibility of using this technique to tackle a variety of highly relevant questions involving ecological, physiological, conservation, restoration and management issues.

This study identified the most common epiphytes infecting the algal host Gracilaria chilensis on a farm in northern Chile. Simultaneously, the types of host–epiphyte interfaces were characterized and their relative abundance and temporal variability were monitored. Five types of anatomical relationships were detected. Infection type I included the epiphytes weakly attached to the surface of the host and not associated with damage of host tissues (i.e. Hincksia mitchelliae, H. granulosa and Ectocarpus acutus). Infection type II included those epiphytes strongly attached to the surface of the host but not associated with any host tissue damage (i.e. Acrochaetium sp., Antithamnionella sp. and Colpomenia sinuosa). Infection type III included all the epiphytes that penetrated the outer layer of the host wall without damaging its cortical cells (i.e. Xenococcus sp. and Sahlingia subintegra). Infection type IV included epiphytes penetrating deep into the host cell wall, disorganizing the cortical tissue (i.e. Ulva lactuca and Acrosorium corallinarum). Infection type V included epiphytes that penetrated deeply into the cortex, reached the medullary tissue and caused destruction of the host’s cells in the area around the infection (i.e. Ceramium rubrum and Polysiphonia harveyi). Prevalence varied with time and with infection type, with types II and III reaching up to 80% and 90% of the thalli respectively. Severity of epiphyte infection was similar to the distribution of infection prevalence, with crustose epiphytes colonizing up to 80% of the host surface. Fil: Leonardi, Patricia Ines. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina Fil: Miravalles, Alicia Beatriz. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentina Fil: Faugeron, Sylvain. Pontificia Universidad Católica de Chile; Chile Fil: Flores, Veronica. Pontificia Universidad Católica de Chile; Chile Fil: Beltrán, Jessica. Pontificia Universidad Católica de Chile; Chile Fil: Correa, Juan A.. Pontificia Universidad Católica de Chile; Chile

Introducción. La exigencia física en los gimnastas durante su formación puede traer consigo lesiones; la intensidad y cantidad de práctica en relación al nivel de competencia y grado de dificultad de los elementos hacen de este deporte uno de los que mayores lesiones produce. Objetivo. Estimar la prevalencia de lesiones y los factores correlacionados a estas en gimnastas pertenecientes a la Liga de Gimnasia de Bogotá, Colombia. Materiales y métodos. Estudio observacional, correlacional y con diseño transversal realizado en 19 gimnastas: nueve mayores de 14 años, nueve entre 15 y 19 y uno de 22 años. Se midió índice de masa corporal (IMC), peso corporal, talla, squat jump, contra movimiento, pliometría en miembros superiores, dinamometría de espalda y sit and reach; también se realizó una encuesta de prevalencia de lesiones. Resultados. 14 deportistas presentaron lesiones el último año. El lugar de lesión más prevalente fue codo con 24%, seguido de pie con 21%. El tipo de lesión más prevalente fue esguince con 31.6%, seguido por tendinopatía con 21%. No hubo correlación entre squat jump, contra movimiento, pliometría en miembros superiores, dinamometría de espalda y sit and reach. Conclusiones. Las variables edad, peso, IMC y duración del entrenamiento se correlacionan con la aparición de lesiones. Las mujeres sufren más lesiones en comparación con hombres. Introduction: The physical demand of gymnasts during training can cause injuries; the intensity and amount of practice in relation to the level of competition and degree of difficulty make this sport present one of the highest rates of injuries.Objective: To estimate the prevalence of injuries and correlated factors in the gymnasts of the Gymnastics League in Bogotá, Colombia.Materials and methods: Observational, correlational and cross-sectional study including 19 gymnasts, whose ages were 14 (nine subjects), 15-19 (nine subjects) and 22 (one subject). Body mass index (BMI), body weight, height, squat jump, counter movement, plyometrics in upper limbs, back dynamometry and sit and reach aspects were measured. Also, a survey of injuries prevalence was performed.Results: 14 athletes had injuries during the past year. The most prevalent injury site was the elbow with 24%, followed by foot with 21%. The most prevalent type of injury was sprain with 31.6%, followed by tendinitis with 21%. There was no correlation between squat jump, counter movement, plyometrics in upper limbs, back dynamometry and sit and reach.Conclusions: The variables age, weight, BMI and length of training correlate with the appearance of injuries. Women suffer more injuries compared with men.

Scytosiphon lomentaria (Lingb.) Link. (Phaeophyceae) is one of the two dominant seaweeds in a coastal area of northern Chile affected by copper mine wastes, where the concentration of copper in water and algal tissues remains higher than in non-impacted sites. Copper-loaded plants develop oxidative stress, as demonstrated by the increased levels of reactive oxygen species and lipoperoxides. This stress was associated with 1) an enhanced activity of the antioxidant enzymes catalase, glutathione peroxidase, ascorbate peroxidase, monodehydroascorbate reductase, and dehydroascorbate reductase and 2) an inhibition of the glutathione reductase activity. Furthermore, stressed plants showed a decrease in glutathione and phenolic compounds levels and an increase in total ascorbate. Reciprocal transplants revealed that plants rapidly adjusted their antioxidant system in response to the conditions of the receiving site. In individuals transplanted from the copper-enriched environment to the control site, normal levels of lipoperoxides and antioxidant compounds were restored in 48 h and antioxidant enzymes recovered their basal activities in 96 h. Individuals transplanted from the control site to the copper-enriched area adjusted their antioxidant compounds and antioxidant enzymes within 48 h and 96 h, respectively, and reached the functional status of the local plants. We conclude that S. lomentaria inhabiting the copper-enriched area buffered oxidative stress by a simultaneous involvement of antioxidant enzymes and water-soluble antioxidant compounds. These antioxidant responses were rapid and reversible, suggesting that copper resistance in S. lomentaria is a constitutive trait and that copper enrichment of the area did not result in a locally adapted copper-tolerant ecotype.

The identity of two phaeophycean taxa that monopolized the middle-lower rocky intertidal zone of a coastal area chronically exposed to copper mine wastes in northern Chile was unraveled. One of them was preliminarily identified as the gametophytic stage of Scytosiphon lomentaria (Lyngbye) Link. The other, a dark crust, resembled the alternate stage of some Scytosiphon species. Comparative analysis of morphology, life history, and DNA sequences strongly suggests that crusts corresponded to sporophytic S. tenellus Kogame and confirm that erect thalli belonged to S. lomentaria. A clear segregation of erect and crustose thalli was found using internal transcribed spacer region 1 and RUBISCO spacer sequences. Furthermore, whereas crusts always grouped with S. tenellus, erect thalli always grouped with S. lomentaria. Life history studies failed to connect the two entities. First, field-collected S. tenellus produced progeny that either recycled the crust, which reproduced by unilocular zoidangia, or developed into erect thalli. The latter, unlike typical gametophytic S. lomentaria, developed patchy sori of plurilocular zoidangia. Second, S. lomentaria displayed a direct-type life cycle, in which progeny from erect individuals only developed into erect thalli and produced only plurilocular zoidangia. This constitutes the first experimental study on Scytosiphon from the Pacific coast of South America and the first report of S. tenellus on this coast. It is also the first report of the crustose stage of Scytosiphon appearing as a perennial and dominant algal species in a temperate rocky intertidal system.

The two agar-producing red algae, Gracilaria chilensis C. J. Bird, McLachlan & E. C. Oliveira and Gracilaria conferta (Schousboe ex Montagne) Montagne, responded with hydrogen peroxide (H2O2) release when agar oligosaccharides were added to the medium. In G. conferta, a transient release was observed, followed by a refractory state of 6 h. This response was sensitive to chemical inhibitors of NADPH oxidase, protein kinases, protein phosphatases, and calcium translocation in the cell, whereas it was insensitive to inhibitors of metalloenzymes. Transmission electron microscopic observations of the H2O2-dependent formation of cerium peroxide from cerium chloride indicated oxygen activation at the plasma membrane of G. conferta. A putative system, consisting of a receptor specific to agar oligosaccharides and a plasma membrane-located NADPH oxidase, appears to be responsible for the release of H2O2 in G. conferta. Subcellular examination of G. chilensis showed that the H2O2 release was located in the cell wall. It was sensitive to inhibitors of metalloenzymes and flavoenzymes, and no refractory state was observed. The release was correlated with accumulation of an aldehyde in the algal medium, suggesting that an agar oligosaccharide oxidase is present in the apoplast of G. chilensis. The presence of this enzyme could also be demonstrated by polyacrylamide electrophoresis under nondenaturating conditions and proven to be variable. Cultivation of G. chilensis at 16 to 17°C resulted in significantly stronger expression of agar oligosaccharide oxidase than cultivation at 12°C, which indicates that the enzyme is used under conditions that generally favor microbial agar macerating activity.

Several coastal rocky shores in northern Chile have been affected by the discharges of copper mine tailings. The present study aims to analyze the chemical speciation of heavy metals in relation to the diversity of sessile species in the rocky intertidal benthic community on the northern Chilean coast, which is influenced by the presence of copper mine tailings. In particular, the chemical forms of Cd, Cu, Fe, Mn, Ni, Pb and Zn in beach sediment samples collected in the area influenced by El Salvador mine tailings were studied using a sequential chemical extraction method. In general, all the elements present a maximum concentration in the area near the actual discharge point (Caleta Palito). With regard to Cu and Mn, the concentrations range between 7.2-985 and 746-22,739 microg/g respectively, being lower than background levels only in the control site of Caleta Zenteno. Moreover, the correlation coefficients highlight that Fe, Mn and Ni correlate significantly and positively in the studied area, showing a possible common, natural origin, whilst Cu shows a negative correlation with Fe, Mn and Ni. It could be possible that Cu has an anthropogenic origin, coming from mining activity in the area. Cd, Fe, Mn, Ni, Pb and Zn are mostly associated with the residual phase, whilst Cu presents a different speciation pattern, as resulted from selective extractions. In fact, Cu is highly associated with organic and exchangeable phases in contaminated localities, whilst it is mainly bound to the residual phase in control sites. Moreover, our results, compared to local biological diversity, showed that those sites characterized by the highest metal concentrations in bioavailable phase had the lowest biodiversity.

This study tests the general hypothesis that habitat disruption caused by the release of copper mine wastes in coastal waters has a negative impact on gene flow among populations of the kelp Lessonia nigrescens Bory. Hierarchical sampling was performed within continuous, undisturbed stands and at the northern and southern edges of a 40 km gap caused by mine wastes. Our results, based on RAPD markers, showed a strong genetic structure even in the absence of the disrupting effect of the mine wastes. No pattern of isolation by distance is apparent, however, which indicates that populations are at migration-drift disequilibrium, and suggests that most events of spore recruit- ment and/or gametophyte fertilization occur within a few metres. On the other hand, some long dis- tance dispersal is likely to occur, which prevents isolation by distance within the spatial scale of 40 km. When comparing continuous stands across the disrupted habitat, an increased genetic differ- entiation associated with the interruption of the species distribution was observed. A Multiple Corre- spondence Analysis (MCA) clearly separated the sampling units into 2 groups, each representing a separate stand. Other lines of evidence supporting the idea of genetic disruption came from the mean pairwise differentiation estimates (FST) and from the Analyses of Molecular Variance (AMOVA). Finally, the southern edge of the interruption in the distribution of L. nigrescens showed clear signals of a recent founding event, suggesting that northward recolonisation is currently occurring.