Contribution of biomass fires to black carbon supply in a tropical river basin assessed using a Lagrangian atmospheric transport model and MODIS burned area product

Black carbon (BC) is known to be a potential sink of carbon for the global carbon cycle, particularly if long-term ocean stores are reached. Fluvial transport to the oceans can occur through the dissolution of BC in river water. Evidence from the Paraiba do Sul river basin, Brazil suggests that river DBC concentration is related to charcoal formed during the deforestation of the Brazilian Atlantic Forest. However, we highlight several key potential sources of BC to the basin that are yet to be considered. We hypothesize that external biomass fires are a source of BC to the basin on the basis that BC released from them can be transported over large distances before being deposited. This hypothesis is tested by quantifying the number of biomass fires intercepted by trajectories en route to the basin using the HYSPLIT model and a MODIS burned area dataset. We then create a Black Carbon Fallout Index (BCFI) which is rationalized by our assumption that atmospheric BC delivery to the basin is proportional to the number of interceptions of air masses en route to the basin. Our results suggest that the BC fallout from air masses reaching the basin in the dry season can explain 50% of the variance in DBC measured in the PSR channel during a subsequent collection campaign (p<.001). Spatial and temporal variations in the supply of BC to the basin throughout the dry season may in part be linked to the fires associated with the cultivation of sugarcane in southeast Brazil

Mid-lower bathyal benthic foraminifera of the Campos Basin, southeastern Brazilian margin: biotopes and controlling ecological factors

Abstrac

Exploring the Pharmacological Potential of Promiscuous Host-Defense Peptides: From Natural Screenings to Biotechnological Applications

In the last few years, the number of bacteria with enhanced resistance to conventional antibiotics has dramatically increased. Most of such bacteria belong to regular microbial flora, becoming a real challenge, especially for immune-depressed patients. Since the treatment is sometimes extremely expensive, and in some circumstances completely inefficient for the most severe cases, researchers are still determined to discover novel compounds. Among them, host-defense peptides (HDPs) have been found as the first natural barrier against microorganisms in nearly all living groups. This molecular class has been gaining attention every day for multiple reasons. For decades, it was believed that these defense peptides had been involved only with the permeation of the lipid bilayer in pathogen membranes, their main target. Currently, it is known that these peptides can bind to numerous targets, as well as lipids including proteins and carbohydrates, from the surface to deep within the cell. Moreover, by using in vivo models, it was shown that HDPs could act both in pathogens and cognate hosts, improving immunological functions as well as acting through multiple pathways to control infections. This review focuses on structural and functional properties of HDP peptides and the additional strategies used to select them. Furthermore, strategies to avoid problems in large-scale manufacture by using molecular and biochemical techniques will also be explored. In summary, this review intends to construct a bridge between academic research and pharmaceutical industry, providing novel insights into the utilization of HDPs against resistant bacterial strains that cause infections in humans

Environmental and sanitary conditions of guanabara bay, Rio de Janeiro

Guanabara Bay is the second largest bay in the coast of Brazil, with an area of 384 km2. 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

Biomagnificación de mercurio en la cadena trófica del Delfín Moteado del Atlántico (Stenella frontalis), usando el isótopo estable de nitrógeno como marcador ecológico

An assessment of mercury (Hg) concentrations and nitrogen stable isotope (15N) was conducted in the food chain of the Atlantic spotted dolphin (Stenella frontalis), including phytoplankton, zooplankton, planktivorous fish and its major prey (predatory fish and a single species of cephalopod), that compose a tropical trophic chain of the Brazilian southeastern coast. Tissue concentrations of Hg in a voracious predator fish, the largehead hairtail (Trichiurus lepturus), one of the dolphin’s prey, were 9.8 times lower than median concentrations found in dolphin tissues. 15N values in predatory fish were found to be lower to those of its predator the spotted dolphin. Isotopic data suggested significant differences for 15N along the trophic chain, with the top predator (dolphin) exhibiting heavier value, followed by the voracious predator fish and the benthonic carnivorous fish, the whitemouth croaker (Micropogonias furnieri). Phytoplankton displayed the lightest 15N, followed by zooplankton and the planktophagous fish, the lebranche mullet (Mugil liza). This fish species and the cephalopod showed the lowest median Hg concentration. All links of the entire trophic chain presented trophic transfer of Hg with a biomagnification factor higher than 1. A significant relationship was found between the log Hg concentration and trophic level (TL) of all evaluated species, with a positive slope (= 0.87). The calculated trophic magnification factor (TMF= 7.44) indicates that Hg concentration increased per TL, and also that the entire coastal food chain from the South Atlantic Ocean presented a biomagnification power of Hg within a range previously reported for tropical coastal ecosystems.Se realizó una evaluación de las concentraciones del mercurio (Hg) y del isótopo estable de nitrógeno (δ15N) en la cadena trófica del Delfín Moteado del Atlántico (Stenella frontalis), incluyendo fitoplancton, zooplancton, peces planctívoros y sus principales presas (peces depredadores y una sola especie de cefalópodo), componentes de una cadena trófica tropical de la costa sureste de Brasil. Una de las presas del delfín, un pez depredador voraz, el pez sable (Trichiurus lepturus), presentó una concentración mediana del Hg 9,8 veces inferior que la del delfín. El valor de 15N es más bajo que al de su depredador. Los datos del isótopo han sugerido que ha habido diferencias significativas para el 15N a lo largo de la cadena trófica, en la que en el mayor depredador (delfín) se ha mostrado más pesado, seguido por el pez depredador y el pez bentófago, la corvina (Micropogonias furnieri). Se ha observado que el fitoplancton presentó el 15N más liviano, seguido por el zooplancton y el pez planctófago, el lebranche (Mugil liza). Este pez y el cefalópodo han mostrado la mediana más baja de Hg. Se han encontrado transferencias mayores que 1 en todos los vínculos de la cadena evaluada. Se ha obtenido una relación significativamente positiva entre la concentración del Hg (en logaritmo) y el nivel trófico (TL), incluyendo todas las especies investigadas, presentando una pendiente positiva (δ= 0,87). El factor de magnificación trófica (FMT= 7,44) indica que la concentración del Hg ha aumentado por TL, y también que toda la cadena trófica costera presentó un poder de biomagnificación de Hg dentro de un rango previamente reportado para ecosistemas costeros tropicales