The influenza virus can cause seasonal infections with mild to severe symptoms, circulating world... more The influenza virus can cause seasonal infections with mild to severe symptoms, circulating worldwide, and it can affect people in any age group. Therefore, this infection is a serious public health problem that causes severe illness and death in high-risk populations. Every year, 0.5% of the world's population is infected by this pathogen. This percentage can increase up to ten times during pandemics. Influenza vaccination is the most effective way to prevent disease. In addition, anti-influenza drugs are essential for prophylactic and therapeutic interventions. The oseltamivir (OST, a neuraminidase inhibitor) is the primary antiviral used in clinics during outbreaks. However, OST resistant viruses may emerge naturally or due to antiviral pressure, with a prevalence of 1-2% worldwide. Thus, the search for new anti-influenza drugs is extremely important. Currently, several groups have been developing studies describing the biotechnological potential of microalgae and cyanobacter...
Most coral reefs have recently experienced acute changes in benthic community structure, generall... more Most coral reefs have recently experienced acute changes in benthic community structure, generally involving dominance shifts from slow-growing hard corals to fast-growing benthic invertebrates and fleshy photosynthesizers. Besides overfishing, increased nutrification and sedimentation are important drivers of this process, which is well documented at landscape scales in the Caribbean and in the Indo-Pacific. However, small-scale processes that occur at the level of individual organisms remain poorly explored. In addition, the generality of coral reef decline models still needs to be verified on the vast realm of turbid-zone reefs. Here, we documented the outcome of interactions between an endangered Brazilian-endemic coral (Mussismilia braziliensis) and its most abundant contacting organisms (turf, cyanobacteria, corals, crustose coralline algae and foliose macroalgae). Our study was based on a long (2006– 2016) series of high resolution data (fixed photoquadrats) acquired along a cross-shelf gradient that includes coastal unprotected reefs and offshore protected sites. The study region (Abrolhos Bank) comprises the largest and richest coralline complex in the South Atlantic, and a foremost example of a turbid-zone reef system with low diversity and expressive coral cover. Coral growth was significantly different between reefs. Coral-algae contacts predominated inshore, while cyanobacteria and turf contacts dominated offshore. An overall trend in positive coral growth was detected from 2009 onward in the inshore reef, whereas retraction in live coral tissue was observed offshore during this period. Turbidity (+) and cyanobacteria (−) were the best predictors of coral growth. Complimentary incubation experiments, in which treatments of Symbiodinium spp. from M. braziliensis colonies were subjected to cyanobacterial exudates, showed a How to cite this article Ribeiro et al. (2018), Long-term effects of competition and environmental drivers on the growth of the endangered coral Mussismilia braziliensis (Verril, 1867). PeerJ 6:e5419; DOI 10.7717/peerj.5419
Current rates of CO2 emissions into the atmosphere are causing severe impacts on the planet. To r... more Current rates of CO2 emissions into the atmosphere are causing severe impacts on the planet. To reduce, or at least stabilize, CO2 concentrations in the atmosphere technological solutions will be needed, such as enhancing biological C-fixation, thus capturing and storing CO2. Following this premise, the capture of carbon content in flue gas emissions (one important anthropogenic source of CO2) would contribute to the decrease of this gas in the atmosphere. In this study we have tested the potential of microalgae to use CO2 from flue gas as source of carbon to produce biomass. We evaluated the growth of four microalgal cultures during direct injection of flue gas. We used both freshwater and marine microalgal cultures. We observed that the four microalgae tested were able to grow using this source of carbon, and that although pH of the cultures decreased in the first hour of flue gas addition, it did not reach inhibitory growth levels. These results show the potential of utilizing this kind of technology to both reduce CO2 emissions, and, at the same time, to produce green biomass with many biotechnological applications. Besides, the use of flue gas as source of carbon makes the whole cultivation process cheaper, contributing to the development of viable, sustainable culturing techniques to the production of microalgae biomass.
Guanabara Bay is the second largest bay in the coast of Brazil, with an area of 384 km(2). In its... more Guanabara Bay is the second largest bay in the coast of Brazil, with an area of 384 km(2). In its surroundings live circa 16 million inhabitants, out of which 6 million live in Rio de Janeiro city, one of the largest cities of the country, and the host of the 2016 Olympic Games. Anthropogenic interference in Guanabara Bay area started early in the XVI century, but environmental impacts escalated from 1930, when this region underwent an industrialization process. Herein we present an overview of the current environmental and sanitary conditions of Guanabara Bay, a consequence of all these decades of impacts. We will focus on microbial communities, how they may affect higher trophic levels of the aquatic community and also human health. The anthropogenic impacts in the bay are flagged by heavy eutrophication and by the emergence of pathogenic microorganisms that are either carried by domestic and/or hospital waste (e.g., virus, KPC-producing bacteria, and fecal coliforms), or that proliferate in such conditions (e.g., vibrios). Antibiotic resistance genes are commonly found in metagenomes of Guanabara Bay planktonic microorganisms. Furthermore, eutrophication results in recurrent algal blooms, with signs of a shift toward flagellated, mixotrophic groups, including several potentially harmful species. A recent large-scale fish kill episode, and a long trend decrease in fish stocks also reflects the bay's degraded water quality. Although pollution of Guanabara Bay is not a recent problem, the hosting of the 2016 Olympic Games propelled the government to launch a series of plans to restore the bay's water quality. If all plans are fully implemented, the restoration of Guanabara Bay and its shores may be one of the best legacies of the Olympic Games in Rio de Janeiro.
Marine substrates are prominent candidates for the production of biofuels, especially for biogas,... more Marine substrates are prominent candidates for the production of biofuels, especially for biogas, which is a well-established technology that accepts different types of substrates for its production. However, the use of marine substrates in bioreactors may cause inhibition of methanogenic bacteria due to the addition of seasalts. Here, we explore a simple and economically viable way to circumvent the problem of inoculum inhibition. Based on the current knowledge of the diversity of microorganisms in marine sediments, we tested the direct use of methanogenic bacteria from an anoxic marine environment as inoculum for biomethane production. Both marine and freshwater substrates were added to this inoculum. No pretreatment (that may have enhanced methane production, but would have made the process more expensive) was applied either to the inoculum or to the substrates. For comparison, the same substrates were added to a standard inoculum (cow manure). Both the marine inoculum and cow manure produced methane by anaerobic digestion of the substrates added. The highest methane production (0.299 m(3) kg VS(-1)) was obtained by adding marine microalgae biomass (Chlorella sp. and Synechococcus sp.) to the marine inoculum. No inhibitory effects were observed due to differences in salinity between the inocula and substrates. Our results indicate the potential of using both marine inoculum and substrates for methane production.
Strong evidence has accumulated on the last years that some algal species are able to kill not o... more Strong evidence has accumulated on the last years that some algal species are able to kill not only their grazers but also other algal species, a process called allelopathy. Killing the nutrient-competing phytoplankton species enable these species to freely utilize limiting resources such as nitrogen and phosphorus. While for some algal species like e.g. the flagellate Pryntnesium sp., the allelochemicals seem to be the same substances as their toxins, for some other algal species they are not. Alexandrium spp. are among the latter case: their internal toxins (such as saxitoxins) are not able to inhibit the growth of other algal species. However, these species by producing other substances than their internal toxins also cause allelopathic effects. Emphasis is placed here on the flagellate species Prymnesium parvum: which is not only able of allelopathy but mixotrophy as well. Mixotrophy, i.e. the capability to ingest bacteria, other algae and even potential grazers, also contributes to the bloom-forming ability of Prytnnesium spp. Allelopathy, mixotrophy and grazer deterrence increase dramatically when Prymnesium spp. cells are grown under N or P deficiency, and so does toxicity, but decrease in intensity or cease completely if cells are grown with high amounts of N and P in balanced proportions. Prymnesium filtrates from nutrient deficient cultures have almost the same strong effect on grazers and other plankton cells as Pryntnesium cells grown together with their target. It seems that toxin production in Pryrnnesium spp. works not only as a defense mechanism, but also, by killing competitors, improve the alga competitive ability under conditions of severe nutrient depletion. We can assume thus that a consequence of the increased input of N and P to aquatic ecosystems is provoking an unbalanced nutrient situation for Prymnesium spp., as well as many of the other HAB species producing toxins, to growth but ideal to produce toxins instead.
The influenza virus can cause seasonal infections with mild to severe symptoms, circulating world... more The influenza virus can cause seasonal infections with mild to severe symptoms, circulating worldwide, and it can affect people in any age group. Therefore, this infection is a serious public health problem that causes severe illness and death in high-risk populations. Every year, 0.5% of the world's population is infected by this pathogen. This percentage can increase up to ten times during pandemics. Influenza vaccination is the most effective way to prevent disease. In addition, anti-influenza drugs are essential for prophylactic and therapeutic interventions. The oseltamivir (OST, a neuraminidase inhibitor) is the primary antiviral used in clinics during outbreaks. However, OST resistant viruses may emerge naturally or due to antiviral pressure, with a prevalence of 1-2% worldwide. Thus, the search for new anti-influenza drugs is extremely important. Currently, several groups have been developing studies describing the biotechnological potential of microalgae and cyanobacter...
Most coral reefs have recently experienced acute changes in benthic community structure, generall... more Most coral reefs have recently experienced acute changes in benthic community structure, generally involving dominance shifts from slow-growing hard corals to fast-growing benthic invertebrates and fleshy photosynthesizers. Besides overfishing, increased nutrification and sedimentation are important drivers of this process, which is well documented at landscape scales in the Caribbean and in the Indo-Pacific. However, small-scale processes that occur at the level of individual organisms remain poorly explored. In addition, the generality of coral reef decline models still needs to be verified on the vast realm of turbid-zone reefs. Here, we documented the outcome of interactions between an endangered Brazilian-endemic coral (Mussismilia braziliensis) and its most abundant contacting organisms (turf, cyanobacteria, corals, crustose coralline algae and foliose macroalgae). Our study was based on a long (2006– 2016) series of high resolution data (fixed photoquadrats) acquired along a cross-shelf gradient that includes coastal unprotected reefs and offshore protected sites. The study region (Abrolhos Bank) comprises the largest and richest coralline complex in the South Atlantic, and a foremost example of a turbid-zone reef system with low diversity and expressive coral cover. Coral growth was significantly different between reefs. Coral-algae contacts predominated inshore, while cyanobacteria and turf contacts dominated offshore. An overall trend in positive coral growth was detected from 2009 onward in the inshore reef, whereas retraction in live coral tissue was observed offshore during this period. Turbidity (+) and cyanobacteria (−) were the best predictors of coral growth. Complimentary incubation experiments, in which treatments of Symbiodinium spp. from M. braziliensis colonies were subjected to cyanobacterial exudates, showed a How to cite this article Ribeiro et al. (2018), Long-term effects of competition and environmental drivers on the growth of the endangered coral Mussismilia braziliensis (Verril, 1867). PeerJ 6:e5419; DOI 10.7717/peerj.5419
Current rates of CO2 emissions into the atmosphere are causing severe impacts on the planet. To r... more Current rates of CO2 emissions into the atmosphere are causing severe impacts on the planet. To reduce, or at least stabilize, CO2 concentrations in the atmosphere technological solutions will be needed, such as enhancing biological C-fixation, thus capturing and storing CO2. Following this premise, the capture of carbon content in flue gas emissions (one important anthropogenic source of CO2) would contribute to the decrease of this gas in the atmosphere. In this study we have tested the potential of microalgae to use CO2 from flue gas as source of carbon to produce biomass. We evaluated the growth of four microalgal cultures during direct injection of flue gas. We used both freshwater and marine microalgal cultures. We observed that the four microalgae tested were able to grow using this source of carbon, and that although pH of the cultures decreased in the first hour of flue gas addition, it did not reach inhibitory growth levels. These results show the potential of utilizing this kind of technology to both reduce CO2 emissions, and, at the same time, to produce green biomass with many biotechnological applications. Besides, the use of flue gas as source of carbon makes the whole cultivation process cheaper, contributing to the development of viable, sustainable culturing techniques to the production of microalgae biomass.
Guanabara Bay is the second largest bay in the coast of Brazil, with an area of 384 km(2). In its... more Guanabara Bay is the second largest bay in the coast of Brazil, with an area of 384 km(2). In its surroundings live circa 16 million inhabitants, out of which 6 million live in Rio de Janeiro city, one of the largest cities of the country, and the host of the 2016 Olympic Games. Anthropogenic interference in Guanabara Bay area started early in the XVI century, but environmental impacts escalated from 1930, when this region underwent an industrialization process. Herein we present an overview of the current environmental and sanitary conditions of Guanabara Bay, a consequence of all these decades of impacts. We will focus on microbial communities, how they may affect higher trophic levels of the aquatic community and also human health. The anthropogenic impacts in the bay are flagged by heavy eutrophication and by the emergence of pathogenic microorganisms that are either carried by domestic and/or hospital waste (e.g., virus, KPC-producing bacteria, and fecal coliforms), or that proliferate in such conditions (e.g., vibrios). Antibiotic resistance genes are commonly found in metagenomes of Guanabara Bay planktonic microorganisms. Furthermore, eutrophication results in recurrent algal blooms, with signs of a shift toward flagellated, mixotrophic groups, including several potentially harmful species. A recent large-scale fish kill episode, and a long trend decrease in fish stocks also reflects the bay's degraded water quality. Although pollution of Guanabara Bay is not a recent problem, the hosting of the 2016 Olympic Games propelled the government to launch a series of plans to restore the bay's water quality. If all plans are fully implemented, the restoration of Guanabara Bay and its shores may be one of the best legacies of the Olympic Games in Rio de Janeiro.
Marine substrates are prominent candidates for the production of biofuels, especially for biogas,... more Marine substrates are prominent candidates for the production of biofuels, especially for biogas, which is a well-established technology that accepts different types of substrates for its production. However, the use of marine substrates in bioreactors may cause inhibition of methanogenic bacteria due to the addition of seasalts. Here, we explore a simple and economically viable way to circumvent the problem of inoculum inhibition. Based on the current knowledge of the diversity of microorganisms in marine sediments, we tested the direct use of methanogenic bacteria from an anoxic marine environment as inoculum for biomethane production. Both marine and freshwater substrates were added to this inoculum. No pretreatment (that may have enhanced methane production, but would have made the process more expensive) was applied either to the inoculum or to the substrates. For comparison, the same substrates were added to a standard inoculum (cow manure). Both the marine inoculum and cow manure produced methane by anaerobic digestion of the substrates added. The highest methane production (0.299 m(3) kg VS(-1)) was obtained by adding marine microalgae biomass (Chlorella sp. and Synechococcus sp.) to the marine inoculum. No inhibitory effects were observed due to differences in salinity between the inocula and substrates. Our results indicate the potential of using both marine inoculum and substrates for methane production.
Strong evidence has accumulated on the last years that some algal species are able to kill not o... more Strong evidence has accumulated on the last years that some algal species are able to kill not only their grazers but also other algal species, a process called allelopathy. Killing the nutrient-competing phytoplankton species enable these species to freely utilize limiting resources such as nitrogen and phosphorus. While for some algal species like e.g. the flagellate Pryntnesium sp., the allelochemicals seem to be the same substances as their toxins, for some other algal species they are not. Alexandrium spp. are among the latter case: their internal toxins (such as saxitoxins) are not able to inhibit the growth of other algal species. However, these species by producing other substances than their internal toxins also cause allelopathic effects. Emphasis is placed here on the flagellate species Prymnesium parvum: which is not only able of allelopathy but mixotrophy as well. Mixotrophy, i.e. the capability to ingest bacteria, other algae and even potential grazers, also contributes to the bloom-forming ability of Prytnnesium spp. Allelopathy, mixotrophy and grazer deterrence increase dramatically when Prymnesium spp. cells are grown under N or P deficiency, and so does toxicity, but decrease in intensity or cease completely if cells are grown with high amounts of N and P in balanced proportions. Prymnesium filtrates from nutrient deficient cultures have almost the same strong effect on grazers and other plankton cells as Pryntnesium cells grown together with their target. It seems that toxin production in Pryrnnesium spp. works not only as a defense mechanism, but also, by killing competitors, improve the alga competitive ability under conditions of severe nutrient depletion. We can assume thus that a consequence of the increased input of N and P to aquatic ecosystems is provoking an unbalanced nutrient situation for Prymnesium spp., as well as many of the other HAB species producing toxins, to growth but ideal to produce toxins instead.
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