Universidade Federal Rural do Rio de Janeiro

About: Universidade Federal Rural do Rio de Janeiro is a education organization based out in Seropédica, Brazil. It is known for research contribution in the topics: Population & Species richness. The organization has 6405 authors who have published 9852 publications receiving 105911 citations.

Environmental Influences on the Demersal Fish Assemblages in the Sepetiba Bay, Brazil

Abstract: The structure of the demersal fish assemblage in Sepetiba Bay, southeast Brazil (22°54′–23°04′S, 43°34′–44°10′W) was described and related to environmental variables. A 3-yr long trawl survey (from July 1993 to June 1996) was conducted using a stratified random sampling strategy at 158 stations. One hundred and seven species of fishes in 80 genera and 44 families were identified. Gerreidae and Ariidae made up 30.5% and 28.6%, and 19.8% and 28.1% of the total number and weight, respectively. Sciaenidae, Engraulididae, Sparidae, and Carangidae were other prominent families. Three assemblages existed in the bay: one inhabited shallow, less saline and less transparent water in the inner zone (depth 10 m, transparency >3 m, salinity >30 psu, and slightly lower temperature); and a third assemblage in the middle zone likely to prefer average values or show no clear preferences. Most species decreased in abundance over the 3-yr period of study. No seasonal change was detected in the assemblage structure, but many species were rare, indicating high spatial and temporal patchiness. Canonical correlation analyses were used to describe and compare the fish assemblages in the three different habitats. The outer zone had the greatest number of species recorded, lowest abundance, highest diversity and evenness, and was comprised mainly byCynossion leiarchus, Prionotus punctatus, Anchoa tricolor, Haemulon steindachneri, Diplectrum radiale, Etropus crossotus, andSphoeroides greeleyi; the inner zone had the lowest number of species recorded but the greatest number of species per sample, highest abundance, lowest diversity and evenness, being comprised mainly byDiapterus rhombeus, Genidens genidens, Cathrops spixii, Chloroschombrus chrysurus, Sciadeichthyes luniscutis, Cetengraulis edentulus, andArchorsargus rhomboidalis; while the third group had the lowest number of species per sample, being comprised by species widely distributed asGerres aprion, G. genidens, Gerres gula, andMicropogonias furnieri. Depth, followed by transparency and salinity, were the primary factors influencing assemblage distribution.

Microencapsulation by spray drying of a lycopene-rich tomato concentrate: Characterization and stability

Abstract: The objective of this study was to evaluate the effect of different encapsulating agents (maltodextrin, whey protein isolate and the modified starch Capsul®) on the physicochemical properties and lycopene stability of a tomato concentrate microencapsulated by spray drying. Different formulations were produced according to an experimental mixture simplex-lattice design, where the independent variables were the concentrations of each encapsulating agent. Physical properties (moisture content, solubility and hygroscopicity), lycopene concentration and the antioxidant capacity of particles immediately after drying, as well as lycopene stability during storage, were analyzed as responses. Particles presented initial lycopene content between 333 and 494 μg/g. The powders produced with maltodextrin and modified starch presented the highest concentrations of this carotenoid and greater antioxidant capacity. These two responses showed high degree of correlation with each other. Maltodextrin and modified starch also led to lower lycopene degradation rates during storage and, therefore, these encapsulating agents were considered the most suitable for the tomato concentrate encapsulation.

Use of fish as intermediate hosts by helminth parasites: A comparative analysis

Abstract: Parasite assemblages of marine fishes include an important number of larval stages of helminth parasite species that use fish as intermediate or as paratenic hosts. In previous comparative studies, larval helminths have typically been lumped with other endoparasites, and there has been therefore no study of the biodiversity and relative abundance of larval helminths and of the factors that may influence them. Here, we performed a comparative analysis across 50 species of teleost fishes from the coast of Brazil; we evaluated the effects of several host traits (body size, social behaviour, feeding habits, preference for benthic or pelagic habitats, depth range, ability to enter brackish waters and geographical distribution) on the richness and abundance of larval helminths. Among all the potential correlates of larval helminth infection investigated in this study, only two were significant when controlling for host phylogenetic influences: Host body length was correlated positively with larval helminth abundance, and fish species with a restricted geographical distribution (Atlantic coast of Brazil mainly) had greater larval helminth abundance than their relatives with a broader (whole Atlantic or cosmopolitan) distribution. Different results were obtained if no correction was made for host phylogeny: Using species values as independent statistical observations, some additional host features also appeared associated with larval helminth species richness or abundance. The results of these analyses indicate that fish phylogeny matters. Apparently, some lineages of fish harbour more larval helminths (more species and/or more individuals) than others merely because of historical reasons (i.e., ancient associations between certain parasite taxa and fish taxa) and not really because of their present ecological characteristics. Acta Parasitologica, 2004, 49(4), 353–361; ISSN 1230-2821 Copyright © 2004 W. Stefanski Institute of Parasitology, PAS

Cooperation between Apoptotic and Viable Metacyclics Enhances the Pathogenesis of Leishmaniasis

Abstract: Mimicking mammalian apoptotic cells by exposing phosphatidylserine (PS) is a strategy used by virus and parasitic protozoa to escape host protective inflammatory responses. With Leishmania amazonensis (La), apoptotic mimicry is a prerogative of the intramacrophagic amastigote form of the parasite and is modulated by the host. Now we show that differently from what happens with amastigotes, promastigotes exposing PS are non-viable, non-infective cells, undergoing apoptotic death. As part of the normal metacyclogenic process occurring in axenic cultures and in the gut of sand fly vectors, a subpopulation of metacyclic promastigotes exposes PS. Apoptotic death of the purified PS-positive (PSPOS) sub-population was confirmed by TUNEL staining and DNA laddering. Transmission electron microscopy revealed morphological alterations in PSPOS metacyclics such as DNA condensation, cytoplasm degradation and mitochondrion and kinetoplast destruction, both in in vitro cultures and in sand fly guts. TUNELPOS promastigotes were detected only in the anterior midgut to foregut boundary of infected sand flies. Interestingly, caspase inhibitors modulated parasite death and PS exposure, when added to parasite cultures in a specific time window. Efficient in vitro macrophage infections and in vivo lesions only occur when PSPOS and PS-negative (PSNEG) parasites were simultaneously added to the cell culture or inoculated in the mammalian host. The viable PSNEG promastigote was the infective form, as shown by following the fate of fluorescently labeled parasites, while the PSPOS apoptotic sub-population inhibited host macrophage inflammatory response. PS exposure and macrophage inhibition by a subpopulation of promastigotes is a different mechanism than the one previously described with amastigotes, where the entire population exposes PS. Both mechanisms co-exist and play a role in the transmission and development of the disease in case of infection by La. Since both processes confer selective advantages to the infective microorganism they justify the occurrence of apoptotic features in a unicellular pathogen.

Recent precipitation trends, flash floods and landslides in southern Brazil

Abstract: In order to understand the rising number offlashfloods and landslides in the densely populated region of southeastern Brazil, this study analyzes the spatial and temporal changes in precipitation from1978 to 2014.We focus on the sensitivity ofmountainous regions, specifically the Rio de Janeiro (RJMR) and SantaCatarina (SCMR) regions. Daily rainfall observations are aggregated into annual and seasonal indexes, andRClimdex is used to evaluate a suite of precipitation and extreme event indexes. Results showpositive annual and seasonal precipitation trends during all seasons except for thewinter season in the RJMR.Diverse change points in their time series, spatial differences in the trends at individual stations, and trends associatedwith elevation suggest that despite the close proximity of these two regions, climate impacts are not uniform across all of southeastern Brazil. Themajority of precipitation-related indexes present positive trends, especially in the extreme precipitation indexes (PRCPTOT, RX1day, Rx5day andR30mm). Statistically significant positive correlations are discovered between landslides/flashfloods events and annualmaximum1-day and 5-day consecutive precipitation, and these indexesmay be useful indicators of natural hazard events for this region.