a-standardized-procedure-for-monitoring-harmful-algal-blooms-chile

A Standardized Procedure for Monitoring Harmful Algal Blooms in Chile by Metabarcoding Analysis

Harmful algae blooms (HABs) monitoring has been implemented worldwide, and Chile, a country famous for its fisheries and aquaculture, has intensively used ...

Universidad de Antofagasta

Semimytilus algosus is a small mussel species that fouls artificial culture systems of the scallop Argopecten purpuratus (Lamarck, 1819) in the north of Chile. Since biofouling organisms are a serious problem in culture, competing with the scallops for food and oxygen, environmentally-friendly methods are required to mitigate the effects of this fouling in the culture systems. The present study reports the evaluation of the inhibitory effect of biofilms and extracellular products (EP) of the bacterium Alteromonas strain Ni1-LEM on the byssal formation of S. algosus juveniles. Laboratory bioassays were carried out to determine the reattachment, exploratory behaviour and/or byssal thread production of the mussel in plastic Petri dishes containing bacterial biofilms, different dilutions of EP, and EP incorporated in a test substratum. It was concluded from the results that culture supernatants of the Alteromonas tested had an inhibitory effect on reattachment by S. algosus.

Inhibition of byssal formation in Semimytilus algosus (Gould, 1850) by a film-forming bacterium isolated from biofouled substrata in northern Chile.

This study reports molecular markers potentially associated with resistance or sensitivity to the impact of copper in juvenile red abalone, Haliotis rufescens, in the north of Chile under experimental conditions. Genomic analysis was made applying subtractive hybridization libraries (SSH) to identify genes up-and down regulated during cooper exposure in abalone over periods of 12 and 168 h exposed to 2.5 and 10 μg/L of Cu(+2). Results obtained from the SSH library revealed 368 different sequences regulated by copper, that correspond to eight major physiological functions. The validation of these sequences obtained by SSH as well as their expression kinetics were made by PCR in real time on 14 potential genes regulated by metal stress. This study provides information for the characterization of potential genomic markers that may be used in future environmental monitoring and to investigate new mechanisms of stress to copper in this commercially important marine species.

Identification of genes expressed in juvenile Haliotis rufescens in response to different copper concentrations in the north of Chile under controlled conditions.

The abalone production in Chile has increased considerably in recent years with no sign of tapering off. Open and semi-closed circuits in the marine water zones in the north and south of Chile are the preferred areas of culture. Coastal ecosystems are subjected to a wide variety of contaminants that generate stress that affects populations via their impacts to individuals at both physiological and genetic levels. This work investigated the genomic and cellular response of post-weaning juvenile Haliotis rufescens abalone under hatchery conditions, fed with probiotic diets, and subsequently challenged with Vibrio parahaemolyticus. The expression patterns of 16 selected genes associated with different metabolic pathways were analyzed using Real-Time PCR. Gene expression was then compared to immunological response parameters in the abalone and quantification of V. parahaemolyticus during the experimental period. Both transcriptomic and immunological analyses indicated significant alteration of physiological processes in H. rufescens correlated to exposure to the pathogenic bacteria, as well as to probiotic nutrition.

Transcriptomic and cellular response to bacterial challenge (pathogenic Vibrio parahaemolyticus) in farmed juvenile Haliotis rufescens fed with or without probiotic diet.

In this study, we designed and evaluated a microalgal pretreatment method using cellulolytic bacteria that naturally degrades microalgae in their native habitat. Bacterial strains were isolated from each of two mollusk species in a medium containing 1% carboxymethyl cellulose agar. We selected nine bacterial strains that had endoglucanase activity: five strains from Mytilus chilensis, a Chilean mussel, and four strains from Mesodesma donacium, a clam found in the Southern Pacific. These strains were identified phylogenetically as belonging to the genera Aeromonas, Pseudomonas, Chryseobacterium, and Raoultella. The cellulase-producing capacities of these strains were characterized, and the degradation of cell walls in Botryococcus braunii and Nannochloropsis gaditana was tested with "whole-cell" cellulolytic experiments. Aeromonas bivalvium MA2, Raoultella ornithinolytica MA5, and Aeromonas salmonicida MC25 degraded B. braunii, and R. ornithinolytica MC3 and MA5 degraded N. gaditana. In addition, N. gaditana was pretreated with R. ornithinolytica strains MC3 and MA5 and was then subjected to an anaerobic digestion process, which increased the yield of methane by 140.32% and 158.68%, respectively, over that from nonpretreated microalgae. Therefore, a "whole-cell" cellulolytic pretreatment can increase the performance and efficiency of biogas production. 

Use of cellulolytic marine bacteria for enzymatic pretreatment in microalgal biogas production.

In the altiplano of Northern Chile the plant  is habitually used as an infusion to relieve the effects of altitude sickness (locally known as "puna"). It is also used to alleviate the bronchitis, whooping cough, asthma, stomachache, tiredness and fever. The extreme conditions under which these plant grow and scientific data that shows the inhibiting potential of the essential oils of plants of the genus  represents great potential in the study of their application to control pathogens like .

A plant from the altiplano of Northern Chile , inhibits the  pathogen.

Biofouling control in reverse osmosis membranes (ROMs) is challenging due to the high cost of treatments, and reduction in the life of ROMs. This study characterizes the biofouling in the ROMs from a desalination plant and reports its effective removal using the supernatant obtained from  sp. strain Ni1-LEM. The characterization of the bacterial community revealed that the most abundant taxa in ROMs were the genera  and , and unclassified species of the families Flavobacteriaceae and Sphingomonadaceae. This bacterial community significantly decreased upon treatment with the supernatant from  sp. Ni1-LEM, resulting in the prevalence of the genus . Furthermore, this bacterial supernatant significantly inhibited cell adhesion of seven benthic microalgae isolated from ROMs as well as promoting cell detachment of the existing microbial biofilms. The study showed that the extracellular supernatant modified the conformation of extracellular polymeric substances (EPS) in the biofouling of ROMs without any biocidal effects.

Characterization and removal of biofouling from reverse osmosis membranes (ROMs) from a desalination plant in Northern Chile, using  sp. Ni1-LEM supernatant.

Omega-3 long-chain polyunsaturated fatty acids (n-3 LC PUFAs) and vitamin D are essential components of human nutrition. A regular human diet is highly deficient in n-3 LC PUFAs. Fish like salmon are highly recommended in the human diet as they are a major source of high-value n-3 LC PUFAs and vitamin D The levels of these nutrients have been decreasing over the last few years in farmed salmon, whose production urgently needs sustainable sources of these nutrients. The microalga  (NG) is known for its naturally high potential for the production of eicosapentaenoic (EPA, 20:5 n-3) fatty acid. A commercial diet for Atlantic salmon was supplemented with 1% and 10% of spray-dried NG grown under controlled conditions for a high EPA content. Salmon were harvested on day 49, following which, boneless and skinless salmon meat was recovered from fish and analyzed for the fatty acid profile, total fat, and vitamin D. Vitamin D, EPA, and docosapentaenoic fatty acid (DPA, 22:5 n-3) levels were significantly increased ( < 0.05) by supplementing the basal diet with 10% NG, thus, NG represents a novel, functional, natural ingredient and a sustainable source of n-3 LC-PUFAs that can raise the levels of healthy fats and vitamin D in farmed salmon meat.

Nutritional Enhancement of Farmed Salmon Meat via Non-GMO Nannochloropsis Gaditana: Eicosapentaenoic Acid (EPA, 20:5 n-3), Docosapentaenoic Acid (DPA, 22:5 n-3) and Vitamin D3 for Human Health.

Harmful algae blooms (HABs) cause acute effects on marine ecosystems due to their production of endogenous toxins or their enormous biomass, leading to significant impacts on local economies and public health. Although HAB monitoring has been intensively performed at spatiotemporal scales in coastal areas of the world over the last decades, procedures have not yet been standardized. HAB monitoring procedures are complicated and consist of many methodologies, including physical, chemical, and biological water sample measurements. Each monitoring program currently uses different combinations of methodologies depending on site specific purposes, and many prior programs refer to the procedures in quotations. HAB monitoring programs in Chile have adopted the traditional microscopic and toxin analyses but not molecular biology and bacterial assemblage approaches. Here we select and optimize the HAB monitoring methodologies suitable for Chilean geography, emphasizing on metabarcoding analyses accompanied by the classical tools with considerations including cost, materials and instrument availability, and easiness and efficiency of performance. We present results from a pilot study using the standardized stepwise protocols, demonstrating feasibility and plausibility for sampling and analysis for the HAB monitoring. Such specific instructions in the standardized protocol are critical obtaining quality data under various research environments involving multiple stations, different analysts, various time-points, and long HAB monitoring duration.

Protocols for Monitoring Harmful Algal Blooms for Sustainable Aquaculture and Coastal Fisheries in Chile.

In this study, we determined the effect of drying on extraction kinetics, yield, and lutein content and recovery of the microalga  sp. (MCH35) using the supercritical fluid extraction (SFE) process. The strain was cultivated in an open-raceways reactor in the presence of seawater culture media and arid outdoor conditions in the north of Chile. Spray-drying (SD) and freeze-drying (FD) techniques were used for dehydrating the microalgal biomass. Extraction experiments were performed by using Box-Behnken designs, and the parameters were studied: pressure (30-50 MPa), temperature (40-70 °C), and co-solvent (0-30% ethanol), with a CO flow rate of 3.62 g/min for 60 min. Spline linear model was applied in the central point of the experimental design to obtain an overall extraction curve and to reveal extraction kinetics involved in the SFE process. A significant increase in all variables was observed when the level of ethanol (15-30% ) was increased. However, temperature and pressure were non-significant parameters in the SFE process. The FD method showed an increase in lutein content and recovery by 0.3-2.5-fold more than the SD method. Overall,  sp. (MCH35) is a potential candidate for cost-effective lutein production, especially in desert areas and for different biotechnological applications.

Effect of Drying Methods on Lutein Content and Recovery by Supercritical Extraction from the Microalga  sp. (MCH35) Cultivated in the Arid North of Chile.

Article	Year
Inhibition of byssal formation in Semimytilus algosus (Gould, 1850) by a film-forming bacterium isolated from biofouled substrata in northern Chile. Biofouling\| PubMed ID: 16551562	2006
Identification of genes expressed in juvenile Haliotis rufescens in response to different copper concentrations in the north of Chile under controlled conditions. Marine pollution bulletin\| PubMed ID: 22001298	2011
Transcriptomic and cellular response to bacterial challenge (pathogenic Vibrio parahaemolyticus) in farmed juvenile Haliotis rufescens fed with or without probiotic diet. Journal of invertebrate pathology\| PubMed ID: 23535139	2013
Use of cellulolytic marine bacteria for enzymatic pretreatment in microalgal biogas production. Applied and environmental microbiology\| PubMed ID: 24795376	2014
A plant from the altiplano of Northern Chile , inhibits the pathogen. SpringerPlus\| PubMed ID: 27795930	2016
Characterization and removal of biofouling from reverse osmosis membranes (ROMs) from a desalination plant in Northern Chile, using sp. Ni1-LEM supernatant. Biofouling\| PubMed ID: 32545993	2020
Nutritional Enhancement of Farmed Salmon Meat via Non-GMO Nannochloropsis Gaditana: Eicosapentaenoic Acid (EPA, 20:5 n-3), Docosapentaenoic Acid (DPA, 22:5 n-3) and Vitamin D3 for Human Heal... Molecules (Basel, Switzerland)\| PubMed ID: 33050537	2020
Protocols for Monitoring Harmful Algal Blooms for Sustainable Aquaculture and Coastal Fisheries in Chile. International journal of environmental research and public health\| PubMed ID: 33092111	2020
Effect of Drying Methods on Lutein Content and Recovery by Supercritical Extraction from the Microalga sp. (MCH35) Cultivated in the Arid North of Chile. Marine drugs\| PubMed ID: 33114504	2020

Carlos Riquelme

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