Atmospheric corrosion and impact toughness of steels: Case study in steels with and without galvanizing, exposed for 3 years in Rapa Nui Island.

We studied atmospheric corrosion on Rapa Nui Island, using galvanized and non-galvanized SAE 1020 steel samples exposed on racks. We also added Charpy samples of both materials to directly determine the effect of corrosion rate on these materials' impact toughness. The results indicated a correlation between corrosion rate and toughness loss in the studied materials. In the corrosion study, we could also demonstrate the effect from increased insular population growth on contaminants which aid atmospheric corrosivity. Results showed that atmospheric SO2 has tripled compared with similar corrosion studies done 20 years ago (Mapa Iberoamericano de Corrosión, MICAT), increasing corrosion rates. Our results show how human factors can influence changes in environmental variables that strengthen corrosion.

Selenium Content in Freshwater and Marine Fish from Southern Brazil Coastal Plain: a Comparative Analysis on Environmental and Dietary Aspects.

The coastal plain of Rio Grande do Sul is considered to be a Se-deficient region in terms of its population dietary habit, making it the focus of this study. Selenium dietary deficiency is a concern when we consider its potential critical health effects on the local population. Therefore, this study contributes new information on the levels of Se in several species of marine and freshwater fish in the region of the Patos-Mirim Lagoon system, coupled with a comparative analysis of the metalloid contents between both fish groups. The Se contents in the fish species ranged from 88 ± 13 to 688 ± 19 µg.kg-1. The average Se concentration in the muscle tissue of the freshwater species (251 ± 96 µg kg-1) was significantly lower than that of the marine species (412 ± 143 µg kg-1). Likewise, no evidence of Se biomagnification was found among the fish from both the marine and freshwater environments, suggesting the absence of trophic transfer of Se. We note that to ensure that the RDA (Recommended Daily Allowance, 55 µg day-1) of Se dietary intake for adults is met, at least 134 g of freshwater or 82 g of marine fish fillet could be incorporated into the diet of the population of Rio Grande do Sul. According to target hazard quotients (THQ) and the permissible safety limits, consumption of the fish species analyzed is safe for human health.

Environmental risks due to the presence of microplastics in coastal and marine environments of the Colombian Caribbean.

Microplastics (MPs) are plastic sediments that are released into the environment by various sources, their abundance and distribution increase as their size decreases, they represent a risk to ecological processes and their abundance is related to their proximity to human activities and The Anthropocene era, in addition to the Covid-19 pandemic, has exacerbated the emitting sources of plastics such as face masks, disinfectant container bottles, among others, all due to all the biosafety measures required globally. Over time, the transformation of plastics into microplastics generates particles transported by atmospheric and water dynamics, being accumulated in soils, bodies of water and incorporated into ecosystems and the food chains of organisms, including humans. Marine-coastal environments such as coastal lagoons, which in addition to hosting strategic ecosystems, being areas of convergence of different ecological flows and with important ecosystem services, have also become sinks for MP particles, putting their productivity and value at risk. Socio-ecological that they have. The purpose of this research is to evaluate and zone the environmental risks derived from contamination by microplastics in a coastal lagoon system, since once the MPs enter the environment they can cause harmful effects, in this case in the Caribbean Sea and in the lagoon complex. To this end, a comprehensive study of planetary systems was carried out to better understand their disturbances due to the presence of microplastics.

Textural characteristics and abundance of microplastics in Tecolutla beach sediments, Gulf of Mexico.

Abundance of microplastics in coastal sediments is considered an emerging pollution problem worldwide. In Mexico, studies focused on microplastics in coastal sediments are little. In this study, we analyzed the textural characteristics and investigated the abundance of microplastics in the Tecolutla beach sediments, SW Gulf of Mexico. The extraction of microplastics in sediments was done by density separation. Microplastics were identified by stereomicroscope and scanning electron microscopy, and were classified based on their morphology, color, length, texture, and abundance. Among 181 microplastics, fiber type is predominant (number of microplastics n = 166; 92%) and followed by film (n = 12; 6%) and fragment (n = 3; 2%) types. The most abundant color of microplastics is black (n = 81; 45%) and second dominant color is blue (n = 65; 36%); most of them are fiber type. Based on the textural characteristics of sediments, it was observed that microplastics were derived from the fluvial contribution of the Tecolutla River and were deposited in the coastal environment by ocean currents. This study revealed that the abundance of microplastics was high in fine-grained sediments and was directly proportional to skewness. The results of this study can act as a reference for understanding the abundance of microplastics in the Gulf of Mexico coastal sediments.

Will there be an improvement of ecosystems in the world post-pandemic?

Purpose/Background. Inconsiderate human activities have led to ecological imbalances, and pollution and degradation of our natural environment. However, for humans to continue to exist on Earth in the future and for sustainable development to occur, we must preserve our ecosystems. Methodology/Approach. This paper examines some ethical considerations that are important to human interaction with the environment, by identifying conditions that existed before the Covid-19 pandemic. Results/Findings. The world is currently challenged by global inequality and global climate change, both of which adversely affect our living environment and very sensitive ecological systems. The physical confinement and social distancing measures imposed by governments worldwide during the Covid-19 pandemic produced a reduction in human interactions and activities which had a positive impact on the ecological environments around the world. Discussion/Conclusions/Contributions. As governments release their citizens from the tight restrictions, and people return to their customary activities, we can expect a return to pollution of our environments. This will occur unless, during the period of 'lockdown', humans had become more aware of the harmful effects some of their activities were having on the ecosystem and had been motivated to minimize these activities.

Propósito/Contexto. Las actividades humanas desconsideradas han llevado a desequilibrios ecológicos y a la contaminación y degradación de nuestro entorno natural, sin embargo, para que los seres humanos sigan existiendo en la Tierra en el futuro y para que se produzca un desarrollo sostenible, debemos preservar nuestros ecosistemas. Metodología/Enfoque. Este documento examina algunas consideraciones éticas que son importantes para la interacción humana con el medio ambiente, al identificar las condiciones que existían antes de la pandemia de COVID-19. Resultados/Hallazgos. Actualmente, el mundo enfrenta el desafío de la desigualdad global y el cambio climático global, los cuales afectan negativamente nuestro entorno de vida y sistemas ecológicos muy sensibles. Las medidas de confinamiento físico y distanciamiento social impuestas por los gobiernos de todo el mundo durante la pandemia de COVID-19 produjeron una reducción en las interacciones y actividades humanas que tuvieron un impacto positivo en los entornos ecológicos de todo el mundo. Discusión/Conclusiones/Contribuciones. A medida que los gobiernos liberan a sus ciudadanos de las estrictas restricciones y las personas regresan a sus actividades habituales, podemos esperar un regreso a la contaminación de nuestro medioambiente. Esto ocurrirá a menos que, durante el periodo de "bloqueo", los humanos se hayan vuelto más conscientes de los efectos nocivos que algunas de sus actividades tenían en el ecosistema y se hayan motivado a minimizar estas actividades.

Finalidade/Contexto. Atividades humanas imprudentes levaram a desequilíbrios ecológicos, poluição e degradação do nosso ambiente natural. No entanto, para que os humanos continuem a existir na Terra no futuro e para que o desenvolvimento sustentável ocorra, devemos preservar nossos ecossistemas. Metodologia/Abordagem. Este artigo examina algumas considerações éticas que são importantes para a interação humana com o meio ambiente, identificando as condições que existiam antes da pandemia de Covid-19. Resultados/Descobertas. O mundo é atualmente desafiado pela desigualdade global e pelas mudanças climáticas globais, que afetam negativamente nosso ambiente de vida e sistemas ecológicos muito sensíveis. As medidas de confinamiento físico e distanciamento social impostas pelos governos em todo o mundo durante a pandemia de Covid-19 produziram uma redução nas interações e atividades humanas que tiveram um impacto positivo nos ambientes ecológicos em todo o mundo. Discussão/Conclusões/Contribuições. À medida que os governos liberam seus cidadãos das rígidas restrições e as pessoas retornam às suas atividades habituais, podemos esperar um retorno à poluição de nossos ambientes. Isso ocorrerá a menos que, durante o período de 'lockdown', os humanos tenham se tornado mais conscientes dos efeitos nocivos que algumas de suas atividades estavam causando no ecossistema e tenham sido motivados a minimizar essas atividades.

Molecular characterization of Sarcocystis spp. in seabirds from southern Brazil.

Sarcocystis spp. are cyst forming apicomplexan parasites that infect many vertebrates including birds. Sarcocystis spp. infection was investigated in tissue samples (pectoral muscles, heart, and brain) of 47 dead seabirds collected from the coastline of Santa Catarina State SC - Brazil, between August 2019 and March 2020. A portion of each tissue was fixed in 10% buffered formalin for histopathologic analysis while DNA was extracted from another portion and screened using nested-PCR targeting ITS1. Based on molecular analysis, Sarcocystis spp. were identified in 15/47 (31.9%) seabirds of five species, kelp gull (Larus dominicanus), manx shearwater (Puffinus puffinus), neotropic cormorant (Phalacrocorax brasilianus), brown booby (Sula leucogaster) and great skua (Stercorarius skua). Microscopically visible sarcocysts were observed only in the pectoral muscle of four seabirds 8.5% (4/47), while in one brown booby, sarcocysts were seen in both pectoral and cardiac muscles. Two types of sarcocysts, thin walled (≤1 µm) and thick-walled (≥ 2 µm) were identified. Based on ITS1 sequence comparison, S. halieti, S. falcatula and three not yet described Sarcocystis spp. were detected. Phylogenetically, S. falcatula isolates were classified as two distinct clusters. This is the first confirmation of S. halieti in seabird's species in South America and S. falcatula in birds of the order Charadriiformes. Further molecular studies are needed to understand the epidemiology of the Sarcocystis spp. infection and its impact on the health of seabirds.

Identification of microplastics and associated contaminants using ultra high resolution microscopic and spectroscopic techniques.

The present study establishes a new procedure to characterize micro(nano)plastics (MNPs) and identify contaminants adhered to the plastic particles in aquatic environments by applying ultra-high resolution microscopy and spectroscopy techniques. Naturally fragmented microplastics (MPs) were collected from Manzanillo and Santiago Bays, Mexico and analyzed using: Confocal Laser Scanning Microscopy (CLSM), Fourier-Transform Infrared Spectroscopy (FTIR), µ-RAMAN, Atomic Force Microscopy (AFM), X-ray Photoelectron Spectroscopy (XPS) and Environmental Electron Scanning Microscopy (ESEM). The information obtained from each of these techniques was integrated to produce a comprehensive profile of each particle. Sample preparation was tested by applying three different rinses (unrinsed, distilled water and alcohol) to untreated MPs collected from Manzanillo Bay, finding that when large impurities are present an alcohol rinse makes it easier to examine the associated contaminants. Based on this emerging methodology, polyethylene and polypropylene MPs were identified with associated contaminants such as arsenic, cadmium, aluminum, and benzene. This study demonstrates the presence of pollutants that may be linked to MNPs in aquatic ecosystems and proposes an accurate relatively fast procedure for their analysis that does not require chemical extraction.

Characterization of Enterobacter cloacae BAGM01 Producing a Thermostable and Alkaline-Tolerant Rhamnolipid Biosurfactant from the Gulf of Mexico.

The search for novel biosurfactants (Bs) requires the isolation of microorganisms from different environments. The Gulf of Mexico (GoM) is a geographical area active in the exploration and exploitation of hydrocarbons. Recent metagenomic and microbiologic studies in this area suggested a potential richness for novel Bs microbial producers. In this work, nineteen bacterial consortia from the GoM were isolated at different depths of the water column and marine sediments. Bs production from four bacterial consortia was detected by the CTAB test and their capacity to reduce surface tension (ST), emulsion index (EI24), and hemolytic activity. These bacterial consortia produced Bs in media supplemented with kerosene, diesel, or sucrose. Cultivable bacteria from these consortia were isolated and identified by bacterial polyphasic characterization. In some consortia, Enterobacter cloacae was the predominant specie. E. cloacae BAGM01 presented Bs activity in minimal medium and was selected to improve its Bs production using a Taguchi and Box-Behnken experimental design; this strain was able to grow and presented Bs activity at 35 g L-1 of NaCl. This Bs decreased ST to around 34.5 ± 0.56 mNm-1 and presented an EI24 of 71 ± 1.27%. Other properties of this Bs were thermal stability, stability in alkaline conditions, and stability at high salinity, conferring important and desirable characteristics in multiple industries. The analysis of the genome of E. cloacae BAGM01 showed the presence of rhlAB genes that have been reported in the synthesis of rhamnolipids, and alkAB genes that are related to the degradation of alkanes. The bioactive molecule was identified as a rhamnolipid after HPLC derivatization, 1H NMR, and UPLC-QTOF-MS analysis.

Marine bacterial community analysis on 316L stainless steel coupons by Illumina MiSeq sequencing.

In order to evaluate the corrosive action of microorganisms on 316L metal exposed directly to a marine environment, a system was designed to immerse coupons in seawater. After periods of 30, 60 and 90 days, the coupons were recovered, the corrosion rates evaluated and the biofilm samples on their surface were analyzed by 16S rRNA gene sequencing. The results of the corrosion rate showed an acceleration over the entire experimental period. Alpha diversity measurements showed higher rates after 60 days of the experiment, while abundance measurements showed higher rates after 90 days of exposure to the marine environment. The beta-diversity results showed a clear separation between the three conditions and proximity in the indices between replicates of the same experimental condition. The results of 16S rRNA gene sequencing showed that after 30 days of exposure to seawater, there was massive representativeness of the pioneer bacteria, Gamma and Alphaproteobacteria, with emphasis on the genera Alcanivorax, Oceanospirillum and Shewanella. At the 60-day analysis, the Gammaproteobacteria class remained dominant, followed by Alphaproteobacteria and Flavobacteria, and the main representatives were Flexibacter and Pseudoalteromonas. In the last analysis, after 90 days, a change in the described bacterial community profile was observed. The Gammaproteobacteria class was still the largest in diversity and OTUs. The most predominant genera in number of OTUs were Alteromonas, Bacteriovorax and, Nautella. Our results describe a change in the microbial community over coupons directly exposed to the marine environment, suggesting a redirection to the formation of a mature biofilm. The conditions created by the biofilm structure suggest said condition favor biocorrosion on the analyzed coupons.

Infecção marinha: abordagem na Atenção Primária / Marine infection: approach in Primary Care / Infección marina: enfoque en la Atención Primaria

Introdução: Cidades litorâneas possuem atividades econômicas como a pesca e o turismo que promovem o contato com a água do mar e, consequentemente, a exposição a microrganismos raramente encontrados em outros contextos e muitas vezes de diagnóstico tardio, podendo resultar em morbidade ou morte significativa. Objetivo: Essa revisão da literatura objetiva mostrar a importância da suspeição da infecção marinha na Atenção Primária, sua etiologia, manifestações clínicas, tratamento, complicações e prevenção. Métodos: Foi realizada pesquisa em bases de dados eletrônicos (SciELO, Google Acadêmico, MEDLINE e PubMed). Resultados: Foram encontrados 135 artigos e vinte foram selecionados, referentes aos anos de 2003 a 2018. Observou-se escassez de estudos que avaliam a efetividade de esquemas de antibioticoterapia e sua duração necessária. Além disso, verificou-se a ausência de classificação no Código Internacional de Doenças (CID-10) e Descritores em Ciências da Saúde (DeCS), fato que prejudica a notificação e estudos epidemiológicos sobre o assunto. Conclusão: É preciso incluir a infecção marinha no diagnóstico diferencial de casos de ferimentos crônicos de difícil diagnóstico, principalmente se houver histórico de exposição a ambiente marinho. Novos estudos se fazem necessários para avaliação da terapêutica adequada. Outrossim, é fundamental conscientizar a população quanto ao risco de infecção marinha e seus métodos de prevenção.

Introduction: Coastal cities have economic activities such as fishing and tourism that promote contact with sea water and consequent exposure to microorganisms rarely found in other contexts. Too often, late diagnosis can result in significant morbidity or death. Objective: This review of the literature aims to show the importance of the differential diagnosis of marine infection in primary care, its etiology, clinical manifestations, treatment, complications and prevention. Methods: Electronic databases (SciELO, Google Scholar, MEDLINE and PubMed) were searched. Results: 135 articles were found and twenty were selected, referring to the years 2003 to 2018. A shortage of studies evaluating the effectiveness of antibiotic therapy regimens and their necessary duration was observed. In addition, the absence of the International Code of Diseases (ICD-10) and Descriptors in Health Sciences (DeCS) was observed, which is detrimental to the epidemiological notification and study on the subject. Conclusion: It is necessary to include marine infection in the differential diagnosis of cases of chronic injuries difficult to diagnose, especially if there is a history of exposure to the marine environment. Further studies are needed to evaluate the appropriate therapy. It is also essential to educate the population about the risk of marine infection and methods of prevention.

Introducción: Las ciudades costeras tienen actividades económicas como la pesca y el turismo que promueven el contacto com la agua del mar y consecuentemente la exposición a microorganismos raramente encontrados em otros contextos y muchas veces de diagnóstico tardío, pudiendo resultar em morbilidad o muerte significativa. Objetivo: Esta revisión de la literatura objetiva mostrar la importancia de la sospecha de la infección marina en la atención primaria, su etiología, manifestaciones clínicas, tratamiento, complicaciones y prevención. Método: Se realizo investigación en bases de datos electrónicos (SciELO, Google Académico, MEDLINE y PubMed). Resultados: Se encontraron 135 artículos y veinte fueron seleccionados, referentes a los años de 2003 a 2018. Se observo escasez de estudios que evalúan la efectividad de esquemas de antibioticoterapia y suduración necesaria. Además, se verifico la ausencia de clasificación en el Código Internacional de Enfermedades (CID-10) y Descriptores em Ciencias de La Salud (DeCS), hecho que perjudica la notificación y estudio epidemiológicos sobre el tema. Conclusión: Es necesario incluir la infección marina em el diagnóstico diferencial de casos de lesiones crónicas de difícil diagnóstico, principalmente si hayun historial de exposición al ambiente marino. Los nuevos estudios se hacen necesarios para evaluar la terapéutica adecuada. También es fundamental concientizar a la población encuanto al riesgo de infección marina y sus métodos de prevención.

Effect of Silica Fume and Fly Ash Admixtures on the Corrosion Behavior of AISI 304 Embedded in Concrete Exposed in 3.5% NaCl Solution.

The use of supplementary cementitious materials such as fly ash, slag, and silica fume improve reinforced concrete corrosion performance, while decreasing cost and reducing environmental impact compared to ordinary Portland cement. In this study, the corrosion behavior of AISI 1018 carbon steel (CS) and AISI 304 stainless steel (SS) reinforcements was studied for 365 days. Three different concrete mixtures were tested: 100% CPC (composite Portland cement), 80% CPC and 20% silica fume (SF), and 80% CPC and 20% fly ash (FA). The concrete mixtures were designed according to the ACI 211.1 standard. The reinforced concrete specimens were immersed in a 3.5 wt.% NaCl test solution to simulate a marine environment. Corrosion monitoring was evaluated using the corrosion potential (Ecorr) according to ASTM C876 and the linear polarization resistance (LPR) according to ASTM G59. The results show that AISI 304 SS reinforcements yielded the best corrosion behavior, with Ecorr values mainly pertaining to the region of 10% probability of corrosion, and corrosion current density (icorr) values indicating passivity after 105 days of experimentation and low probability of corrosion for the remainder of the test period.

Non-native marine bryozoans (Bryozoa: Gymnolaemata) in Brazilian waters: Assessment, dispersal and impacts.

Bryozoa is a phylum of aquatic invertebrates widely distributed around the world, including harbor areas. They have association to artificial structures as main mechanism of dispersal, including ships, which facilitates their introduction to new environments. The detection of exotic species is important to prevent new introductions and to propose management strategies of marine areas. Thus, after analyzing and discussing local and global criteria of exotic species, an account of exotic bryozoans from Brazil is presented, including 12 classified as exotic (six established and six detected) and 17 classified as potentially exotic (cryptogenic). Three species have been reported causing economic or environmental impacts worldwide. Of those, Membraniporopsis tubigera is known to cause economic impacts on the Brazilian coast. Hull fouling is the main dispersal mechanism for exotic bryozoans. The lacking of reliable data did not allow inferring on the exotic status on some fouling bryozoan species in Brazil.

Anaerobic ammonium oxidation linked to sulfate and ferric iron reduction fuels nitrogen loss in marine sediments.

Availability of fixed nitrogen is a pivotal driver on primary productivity in the oceans, thus the identification of key processes triggering nitrogen losses from these ecosystems is of major importance as they affect ecosystems function and consequently global biogeochemical cycles. Denitrification and anaerobic ammonium oxidation coupled to nitrite reduction (Anammox) are the only identified marine sinks for fixed nitrogen. The present study provides evidence indicating that anaerobic ammonium oxidation coupled to the reduction of sulfate, the most abundant electron acceptor present in the oceans, prevails in marine sediments. Tracer analysis with 15N-ammonium revealed that this microbial process, here introduced as Sulfammox, accounts for up to 5 µg 15N2 produced g-1 day-1 in sediments collected from the eastern tropical North Pacific coast. Raman and X-ray diffraction spectroscopies revealed that elemental sulfur and sphalerite (ZnFeS) were produced, besides free sulfide, during the course of Sulfammox. Anaerobic ammonium oxidation linked to Fe(III) reduction (Feammox) was also observed in the same marine sediments accounting for up to 2 µg 15N2 produced g-1 day-1. Taxonomic characterization, based on 16S rRNA gene sequencing, of marine sediments performing the Sulfammox and Feammox processes revealed the microbial members potentially involved. These novel nitrogen sinks may significantly fuel nitrogen loss in marine environments. These findings suggest that the interconnections among the oceanic biogeochemical cycles of N, S and Fe are much more complex than previously considered.

The Resistome of Low-Impacted Marine Environments Is Composed by Distant Metallo-ß-Lactamases Homologs.

The worldwide dispersion and sudden emergence of new antibiotic resistance genes (ARGs) determined the need in uncovering which environment participate most as their source and reservoir. ARGs closely related to those currently found in human pathogens occur in the resistome of anthropogenic impacted environments. However, the role of pristine environment as the origin and source of ARGs remains underexplored and controversy, particularly, the marine environments represented by the oceans. Here, due to the ocean nature, we hypothesized that the resistome of this pristine/low-impacted marine environment is represented by distant ARG homologs. To test this hypothesis we performed an in silico analysis on the Global Ocean Sampling (GOS) metagenomic project dataset focusing on the metallo-ß-lactamases (MßLs) as the ARG model. MßLs have been a challenge to public health, since they hydrolyze the carbapenems, one of the last therapeutic choice in clinics. Using Hidden Markov Model (HMM) profiles, we were successful in identifying a high diversity of distant MßL homologs, related to the B1, B2, and B3 subclasses. The majority of them were distributed across the Atlantic, Indian, and Pacific Oceans being related to the chromosomally encoded MßL GOB present in Elizabethkingia genus. It was observed only a reduced number of metagenomic sequence homologs related to the acquired MßL enzymes (VIM, SPM-1, and AIM-1) that currently have impact in clinics. Therefore, low antibiotic impacted marine environment, as the ocean, are unlikely the source of ARGs that have been causing enormous threat to the public health.

A tiered approach to assess effects of diclofenac on the brown mussel Perna perna: A contribution to characterize the hazard.

Pharmaceutical discharges into the aquatic ecosystem are of environmental concern and sewage treatment plants (STPs) have been pointed out as the major source of these compounds to coastal zones, where oceanic disposal of sewage occurs through submarine outfalls. Diclofenac (DCF) is one of the most frequently detected pharmaceuticals in water, but little is known about the effects on marine organisms. In this study, we employed a tiered approach involving the determination of environmental concentrations of DCF in marine water and the adverse biological effects for fertilization, embryo-larval development and biomarker responses of the mussel Perna perna. Results indicate that effects in fertilization rate and embryo-larval development were found in the order of mg·L-1. However, low concentrations of DCF (ng·L-1) significantly decreased the lysosomal membrane stability and COX activity, as well as triggered DNA damage, oxidative stress and changes in antioxidant defenses. Our results point to an environmental hazard at coastal ecosystems and suggest the need for improvements in the treatment of domestic wastewater aiming to reduce DCF concentrations, as well as regulation on current environmental legislation and monitoring of aquatic ecosystems.

Comment (1) on "Formation of the Isthmus of Panama" by O'Dea et al.

A review and reanalysis of geological, molecular, and paleontological data led O'Dea et al. (1) to propose (i) that reports by Montes et al. (2) and Bacon et al. (3) regarding a middle Miocene closure of the Central American Seaway (CAS) are unsupported, and (ii) a new age of the formation of the Isthmus at 2.8 million years ago (Ma). Here, we reject both of these conclusions.

Coupling between anammox and autotrophic denitrification for simultaneous removal of ammonium and sulfide by enriched marine sediments.

In the present study, the capacity of enrichments derived from marine sediments collected from different sites of the Mexican littoral to perform anaerobic ammonium oxidation (anammox) coupled to sulfide-dependent denitrification for simultaneous removal of ammonium and sulfide linked to nitrite reduction was evaluated. Sulfide-dependent denitrification out-competed anammox during the simultaneous oxidation of sulfide and ammonium. Significant accumulation of elemental sulfur (ca. 14-30 % of added sulfide) occurred during the coupling between the two respiratory processes, while ammonium was partly oxidized (31-47 %) due to nitrite limitation imposed in sediment incubations. Nevertheless, mass balances revealed up to 38 % more oxidation of the electron donors available (ammonium and sulfide) than that expected from stoichiometry. Recycling of nitrite, from nitrate produced through anammox, is proposed to contribute to extra oxidation of sulfide, while additional ammonium oxidation is suggested by sulfate-reducing anammox (SR-anammox). The complex interaction between nitrogenous and sulfurous compounds occurring through the concomitant presence of autotrophic denitrification, conventional anammox and SR-anammox may significantly drive the nitrogen and sulfur fluxes in marine environments.

Occurrence of pharmaceuticals and cocaine in a Brazilian coastal zone.

The present study determined environmental concentrations of pharmaceuticals, cocaine, and the main human metabolite of cocaine in seawater sampled from a subtropical coastal zone (Santos, Brazil). The Santos Bay is located in a metropolitan region and receives over 7367m(3) of wastewater per day. Five sample points under strong influence of the submarine sewage outfall were chosen. Through quantitative analysis by LC-MS/MS, 33 compounds were investigated. Seven pharmaceuticals (atenolol, acetaminophen, caffeine, losartan, valsartan, diclofenac, and ibuprofen), an illicit drug (cocaine), and its main human metabolite (benzoylecgonine) were detected at least once in seawater sampled from Santos Bay at concentrations that ranged from ng·L(-1) to µg·L(-1). In light of the possibility of bioaccumulation and harmful effects, the high concentrations of pharmaceuticals and cocaine found in this marine subtropical ecosystem are of environmental concern.

Actividad antagonista de bacterias lácticas aisladas del medio marino contra cepas de Listeria / Antagonistic activity of lactic bacteria isolated from marine environment against Listeria strains / Atividade antagonista de bactérias lácticas isoladas do meio marinho contra cepas de Listeria

En el presente trabajo se estudiaron 74 bacterias lácticas para determinar su capacidad de inhibir el desarrollo de Listeria monocytogenes ATCC 7644 o L. innocua ATCC 33090. Dentro de las 7 que exhibieron actividad, 2 se seleccionaron para estudios complementarios y se identificaron por métodos fenotípicos y genotípicos como Enterococcus mundtii Tw 56 y Lactococcus lactis subsp. lactis Tw 34. Después de la neutralización con NaOH y tratamiento térmico (100 ºC y 121 ºC durante 5 min) la actividad antagonista del sobrenadante libre de células se mantuvo activa. El tratamiento con lisozima, lipasa y catalasa no afectó la actividad antimicrobiana. Sin embargo, la actividad enzimática de la tripsina suprimió la acción inhibitoria del sobrenadante, confirmando la naturaleza proteica del compuesto activo. En ambos casos, el título de la actividad antilisteria no se vio afectado luego de la inducción mediada por nisina o galactosa. La combinación de los sobrenadantes libres de células no exhibió antagonismo o sinergia. Las características bioquímicas y fisicoquímicas de los agentes antilisteria producidos por las cepas seleccionadas sugieren que pueden ser clasificadas como bacteriocinas tipo I o II. Se deben realizar estudios complementarios para determinar el uso potencial de las cepas seleccionadas como cultivos bioprotectores en el control de la seguridad alimentaria.

In the present work, 74 strains of lactic bacteria isolated from the marine environment were studied in order to determinate their ability to inhibit the growth of Listeria monocytogenes ATCC 7644 or L. innocua ATCC 33090. Among the 7 strains that exhibited some activity, 2 were selected for further studies and identified by phenotypic and genotypic methods as Enterococcus mundtii Tw 56 y Lactococcus lactis subsp. lactis Tw 34. After neutralization with NaOH and heat treatment (100 ºC and 121 ºC for 5 min) the antagonistic activity of cell-free supernatants of the two strains studied remained active. Treatment with lysozime, lipase and catalase did not affect the antimicrobial activity; however enzymatic activity of trypsin abolished the inhibitory action of the supernatant, confirming the proteinacious nature of the active compound. In both cases, the titre of antilisterial activity was not affected after nisin or galactose-mediated induction. The combination of cell-free supernatants of both strains did not display antagonism or synergy. The biochemical and physicochemical characteristics of antilisterial agents produced by the selected strains suggest that they can be classified as type I or II bacteriocins. Further studies will be adressed to determine the potential use of the selected strains as bioprotective cultures in food safety control.

No presente trabalho foram estudadas 74 bactérias lácticas para determinar sua capacidade de inibir o desenvolvimento de Listeria monocytogenes ATCC 7644 ou L. innocua ATCC 33090. Dentro das 7 que exibiram atividade, 2 foram selecionadas para estudos complementares e se identificaram por métodos fenotípicos e genotípicos como Enterococcus mundtii Tw 56 e Lactococcus lactis subsp. lactis Tw 34. Depois da neutralização com NaOH e tratamento térmico (100 ºC e 121 ºC durante 5 min) a atividade antagonista do sobrenadante livre de células se manteve ativa. O tratamento com lisozima, lipase e catalase não afetou a atividade antimicrobiana. Entretanto, a atividade enzimática da tripsina suprimiu a ação inibidora do sobrenadante, confirmando a natureza proteica do composto ativo. Em ambos os casos, o título da atividade antilisteria não se viu afetado depois da indução mediada por nisina ou galactose. A combinação dos sobrenadantes livres de células não exibiu antagonismo ou sinergia. As características bioquímicas e fisioquimicas dos agentes antilisteria produzidos pelas cepas selecionadas sugerem que podem ser classificadas como bacteriocinas tipo I ou II. Devem ser realizados estudos complementares para determinar o uso potencial das cepas selecionadas como culturas bioprotetoras no controle da segurança alimentar.