There is great microalgae biodiversity and their rediscovery as an inexhaustible source of biotec... more There is great microalgae biodiversity and their rediscovery as an inexhaustible source of biotechnological resources for all types of applications is leading to the already demonstrated benefits of their bioactive compounds which has boosted their industrial development. For this development, it is essential to have available technologies to easily control large-scale cultures. In this study, a high-resolution melting (HRM) analysis was developed to identify different microalgae that are currently used by the industry. HRM analysis is a simple, economical, fast, and reproducible method that allows the use of a stable molecule such as DNA to track a culture day by day without the need for visual microscopic controls. Ten microalgae were characterized by qPCR-HRM analysis: Isochrysis galbana, Phaeodactylum tricornutum, Muriellopsis sp., Porphyridium cruentum, Botryococcus braunii, Nannochloropsis gaditana, Chlorella sorokiniana, Chlamydomonas reinhardtii, Haematococcus pluvialis, and Scenedesmus obliquus. We determined that through the use of primers designed specifically for the 18S rDNA ribosomal gene, it is possible to significantly discriminate among the ten strains simultaneously by using HRM analysis. The results are also replicable over time, facilitating the daily and low-cost control of species used in the biotechnology industry.
Journal of Experimental Marine Biology and Ecology
Abstract Several drawbacks have emerged on the welfare status of shellfishes grown intensively in... more Abstract Several drawbacks have emerged on the welfare status of shellfishes grown intensively in natural estuaries, such as density-dependent competition, overexploitation, low growth, and harmful algae blooming episodes (HAB), which anticipate profound socioeconomic consequences. The improvement of body size would hitchhike other growth surrogates and is a natural solution to increase productivity and circumvent HAB by shortening the production cycle. Such improvement in aquaculture depends on the existence of genotypic variation in quantitative traits. Namely, heritability plays a predictive role in the study of metric characters because it measures the resemblance between the phenotypic value and the breeding value. The aim of this study was to estimate variance components and interaction phenomena on shell length of the quasi-sessile marine invertebrate M. galloprovincialis grown in a Hatchery Environment Nucleus (HEN) and replicated in a Production Environment (PDE). A large amount of additive variation for shell length exists in M. galloprovincialis which broad-sense heritability after the animal model was higher in the richer production environment ( h ¯ 2AM_PDE = 0.643 ± 0.066) than in the hatchery environment ( h ¯ 2AM_HEN = 0.606 ± 0.127). The stability of the phenotypic variation (Vp) observed in HEN, suggests the increasing weight of the non-additive genetic variance which makes h2 increase with age. The reaction norm showed a reduced phenotypic variance in PDE as a byproduct of a change in scale as well as in ranking due to the presence of Genetic by Environment Interaction (GEI). Therefore, quantitative parameters recorded in the farm (HEN) should not be employed to extrapolate potential growth in the production field (PDE). Provided that selection accuracy depends on both, Family by Environment Interaction (FEI) and GEI, evaluation in the breeding nucleus entailed a global 5.35% gain overestimation (∆G = + 3.74 mm in shell length) on the expected phenotypic gain in PDE of the directional L lines constructed. Correction for accuracy and genetic correlation indicates that a selective breeding program for directional selection could yield a 9% (6 mm in shell length) gain in the first generation at PDE what could allow to attain a significant production cycle shortening in few generations of selection.
ABSTRACT Reproduction in tunicates is considered to be particularly vulnerable to changes in seaw... more ABSTRACT Reproduction in tunicates is considered to be particularly vulnerable to changes in seawater temperature. In the present study we investigated the effects of sea surface temperature and temperature anomalies on reproductive traits of the non-native sessile tunicate Pyura praeputialis. Reproductive traits of this species were investigated over the course of 67 months, based on samples collected at two localities (eastern and western shorelines) of the Bay of Antofagasta. The study period included years with different oceanic and atmospheric conditions: a warm event, El Niño (June 1997 to July 1998); a cold event, La Niña (August 1998 to December 2000); and post-La Niña (January 2000 to December 2002). We compared two common indices (condition and gonadosomatic) and histological sections to evaluate the maximum reproduction index of this introduced species that dominates a large part of the rocky intertidal habitat in the Bay of Antofagasta. We found sexually mature individuals all year-round and a decrease in both reproductive indices matching the reduction in the sea surface temperature during the austral autumn and winter months. The results suggest that gonad development in this species is sensitive to sea surface temperature and thermal anomalies. We conclude that future thermal anomalies or projected global average sea surface warming associated with climate change might have no negative consequences on these reproductive traits of P. praeputialis. This suggests this species is ecologically resilient and that the ecosystem services that this species provides for other invertebrate and algal species will be maintained.
Journal of the Marine Biological Association of the United Kingdom, 2016
Reproductive cycles were studied in seven natural populations of the intertidal bivalve Perumytil... more Reproductive cycles were studied in seven natural populations of the intertidal bivalve Perumytilus purpuratus, distributed in a latitudinal gradient of ~2400 km along the Chilean Pacific coast (20–40°S). The results, both qualitative (gametogenic stages) and quantitative (GSI and GVF), over a period of 24 months, showed that these populations presented asynchrony in the reproductive cycle. Semi-annual cycles in Iquique (20°S), Antofagasta (23°S) and Montemar (32°S), and annual cycles in Caleta Bolfin (23°S), Taltal (25°S), Tumbes (36°S) and Pucatrihue (40°S) (2010–2012) were found. The results indicate that latitude does not have an effect on the development stage, but it does on the spawning date. However, there is a relationship between the reproductive cycles and temperature fluctuations. In addition, there was a significant negative linear correlation between gonadosomatic index and sea surface temperature in the populations studied. The decrease in temperature reduces the rate...
Abstract Historical processes leading to the emergence of marine stocks, the mechanisms maintaini... more Abstract Historical processes leading to the emergence of marine stocks, the mechanisms maintaining stock structure, and present-day connectivity patterns are elementary pieces of information to design wiser and more sustainable management of marine resources, and to understand speciation processes in the sea. Over geographical scales, biological and genetic continuity in the Southern Pacific coast is determined by historical geological-climate events (e.g., LGM), as well as by present oceanographic processes (Humboldt Current, ENSO and others) that can affect both, local adaptation and dispersal. The relative influence of such processes on the current distribution of species can be comprehensibly inferred from a detailed population sampling comprising the whole species range. In this work, we aimed to provide insights into historical and modern patterns of genetic connectivity between stocks of the intertidal mussel Perumytilus purpuratus , a species reported to have moderate pelagic development times of about 14–18 days. To this end, we analyzed the geographical pattern of variation of microsatellite polymorphisms across 17 localities scattered along ca. 4500 km off the Chilean Coast and encompassing four biogeographic regions, previously defined based on compositional changes in marine flora and fauna, and which coincide with large changes in topography, the historical influence of glaciation, circulation patterns and upwelling variability around 26°S, 30°S and 40°S. Genetic structural data suggest that historical geological and climatic events have shaped the actual range of this species in the south-eastern Pacific, creating biogeographical limits, i.e., the north-central stock and the southern stock, that moderate to restricted dispersers cannot cross given present day coastal oceanographic processes. Conversely, the pattern of IBD observed within those two major biogeographical regions suggests that present-day coastal processes modulate the effective dispersal of this species.
There is great microalgae biodiversity and their rediscovery as an inexhaustible source of biotec... more There is great microalgae biodiversity and their rediscovery as an inexhaustible source of biotechnological resources for all types of applications is leading to the already demonstrated benefits of their bioactive compounds which has boosted their industrial development. For this development, it is essential to have available technologies to easily control large-scale cultures. In this study, a high-resolution melting (HRM) analysis was developed to identify different microalgae that are currently used by the industry. HRM analysis is a simple, economical, fast, and reproducible method that allows the use of a stable molecule such as DNA to track a culture day by day without the need for visual microscopic controls. Ten microalgae were characterized by qPCR-HRM analysis: Isochrysis galbana, Phaeodactylum tricornutum, Muriellopsis sp., Porphyridium cruentum, Botryococcus braunii, Nannochloropsis gaditana, Chlorella sorokiniana, Chlamydomonas reinhardtii, Haematococcus pluvialis, and Scenedesmus obliquus. We determined that through the use of primers designed specifically for the 18S rDNA ribosomal gene, it is possible to significantly discriminate among the ten strains simultaneously by using HRM analysis. The results are also replicable over time, facilitating the daily and low-cost control of species used in the biotechnology industry.
Journal of Experimental Marine Biology and Ecology
Abstract Several drawbacks have emerged on the welfare status of shellfishes grown intensively in... more Abstract Several drawbacks have emerged on the welfare status of shellfishes grown intensively in natural estuaries, such as density-dependent competition, overexploitation, low growth, and harmful algae blooming episodes (HAB), which anticipate profound socioeconomic consequences. The improvement of body size would hitchhike other growth surrogates and is a natural solution to increase productivity and circumvent HAB by shortening the production cycle. Such improvement in aquaculture depends on the existence of genotypic variation in quantitative traits. Namely, heritability plays a predictive role in the study of metric characters because it measures the resemblance between the phenotypic value and the breeding value. The aim of this study was to estimate variance components and interaction phenomena on shell length of the quasi-sessile marine invertebrate M. galloprovincialis grown in a Hatchery Environment Nucleus (HEN) and replicated in a Production Environment (PDE). A large amount of additive variation for shell length exists in M. galloprovincialis which broad-sense heritability after the animal model was higher in the richer production environment ( h ¯ 2AM_PDE = 0.643 ± 0.066) than in the hatchery environment ( h ¯ 2AM_HEN = 0.606 ± 0.127). The stability of the phenotypic variation (Vp) observed in HEN, suggests the increasing weight of the non-additive genetic variance which makes h2 increase with age. The reaction norm showed a reduced phenotypic variance in PDE as a byproduct of a change in scale as well as in ranking due to the presence of Genetic by Environment Interaction (GEI). Therefore, quantitative parameters recorded in the farm (HEN) should not be employed to extrapolate potential growth in the production field (PDE). Provided that selection accuracy depends on both, Family by Environment Interaction (FEI) and GEI, evaluation in the breeding nucleus entailed a global 5.35% gain overestimation (∆G = + 3.74 mm in shell length) on the expected phenotypic gain in PDE of the directional L lines constructed. Correction for accuracy and genetic correlation indicates that a selective breeding program for directional selection could yield a 9% (6 mm in shell length) gain in the first generation at PDE what could allow to attain a significant production cycle shortening in few generations of selection.
ABSTRACT Reproduction in tunicates is considered to be particularly vulnerable to changes in seaw... more ABSTRACT Reproduction in tunicates is considered to be particularly vulnerable to changes in seawater temperature. In the present study we investigated the effects of sea surface temperature and temperature anomalies on reproductive traits of the non-native sessile tunicate Pyura praeputialis. Reproductive traits of this species were investigated over the course of 67 months, based on samples collected at two localities (eastern and western shorelines) of the Bay of Antofagasta. The study period included years with different oceanic and atmospheric conditions: a warm event, El Niño (June 1997 to July 1998); a cold event, La Niña (August 1998 to December 2000); and post-La Niña (January 2000 to December 2002). We compared two common indices (condition and gonadosomatic) and histological sections to evaluate the maximum reproduction index of this introduced species that dominates a large part of the rocky intertidal habitat in the Bay of Antofagasta. We found sexually mature individuals all year-round and a decrease in both reproductive indices matching the reduction in the sea surface temperature during the austral autumn and winter months. The results suggest that gonad development in this species is sensitive to sea surface temperature and thermal anomalies. We conclude that future thermal anomalies or projected global average sea surface warming associated with climate change might have no negative consequences on these reproductive traits of P. praeputialis. This suggests this species is ecologically resilient and that the ecosystem services that this species provides for other invertebrate and algal species will be maintained.
Journal of the Marine Biological Association of the United Kingdom, 2016
Reproductive cycles were studied in seven natural populations of the intertidal bivalve Perumytil... more Reproductive cycles were studied in seven natural populations of the intertidal bivalve Perumytilus purpuratus, distributed in a latitudinal gradient of ~2400 km along the Chilean Pacific coast (20–40°S). The results, both qualitative (gametogenic stages) and quantitative (GSI and GVF), over a period of 24 months, showed that these populations presented asynchrony in the reproductive cycle. Semi-annual cycles in Iquique (20°S), Antofagasta (23°S) and Montemar (32°S), and annual cycles in Caleta Bolfin (23°S), Taltal (25°S), Tumbes (36°S) and Pucatrihue (40°S) (2010–2012) were found. The results indicate that latitude does not have an effect on the development stage, but it does on the spawning date. However, there is a relationship between the reproductive cycles and temperature fluctuations. In addition, there was a significant negative linear correlation between gonadosomatic index and sea surface temperature in the populations studied. The decrease in temperature reduces the rate...
Abstract Historical processes leading to the emergence of marine stocks, the mechanisms maintaini... more Abstract Historical processes leading to the emergence of marine stocks, the mechanisms maintaining stock structure, and present-day connectivity patterns are elementary pieces of information to design wiser and more sustainable management of marine resources, and to understand speciation processes in the sea. Over geographical scales, biological and genetic continuity in the Southern Pacific coast is determined by historical geological-climate events (e.g., LGM), as well as by present oceanographic processes (Humboldt Current, ENSO and others) that can affect both, local adaptation and dispersal. The relative influence of such processes on the current distribution of species can be comprehensibly inferred from a detailed population sampling comprising the whole species range. In this work, we aimed to provide insights into historical and modern patterns of genetic connectivity between stocks of the intertidal mussel Perumytilus purpuratus , a species reported to have moderate pelagic development times of about 14–18 days. To this end, we analyzed the geographical pattern of variation of microsatellite polymorphisms across 17 localities scattered along ca. 4500 km off the Chilean Coast and encompassing four biogeographic regions, previously defined based on compositional changes in marine flora and fauna, and which coincide with large changes in topography, the historical influence of glaciation, circulation patterns and upwelling variability around 26°S, 30°S and 40°S. Genetic structural data suggest that historical geological and climatic events have shaped the actual range of this species in the south-eastern Pacific, creating biogeographical limits, i.e., the north-central stock and the southern stock, that moderate to restricted dispersers cannot cross given present day coastal oceanographic processes. Conversely, the pattern of IBD observed within those two major biogeographical regions suggests that present-day coastal processes modulate the effective dispersal of this species.
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Papers by Ricardo Guinez