The introduction of species has become an important problem for biodiversity and natural ecosystem conservation. The lake system of the middle Rio Doce (MG, Brazil) comprises c. 200 lakes at various ...conservation states, of which 50 are located within the Rio Doce State Park (PERD). Previous studies had verified several of these lakes suffered non-native fishes introductions and the presence of these species needs for the implementation of actions aiming at not only their control but also the preservation of the native species. This study discusses the effects of non-native fish species in the largest conservation unit of Atlantic Forest in Minas Gerais, southeast of Brazil, using data from 1983 to 2010 distributed as follow: data prior to 2006 were obtained from previous studies, and data from September 2006 to July 2010 were obtained in Lake Carioca at four sampling stations using gillnets, seine nets and sieve. A total of 17 fish species was collected (2006-2010) of which five were introduced species. Among the small to medium size native species (30 to 2000 mm standard length) seven had disappeared, two are new records and one was recaptured. The non-native species Cichla kelberi (peacock bass) and Pygocentrus nattereri (red piranha) are within the most abundant captured species. Integrated with other actions, such as those preventing new introductions, a selective fishing schedule is proposed as an alternative approach to improve the conservation management actions and the local and regional biodiversity maintenance.
Abstract Acute lung injury is an inflammation that triggers acute respiratory distress syndrome with perialveolar neutrophil infiltration, alveolar-capillary barrier damage, and lung edema. ...Activation of the toll-like receptor 4 complex (TLR4/MD2) and its downstream signaling pathways are responsible for the cytokine storm and cause alveolar damage. Due to the complexity of this pulmonary inflammation, a defined pharmacotherapy has not been established. Thus, this study evaluated the anti-inflammatory potential of milonine, an alkaloid of Cissampelos sympodialis Eichl, in an experimental model of lung inflammation. BALB/c mice were lipopolysaccharide-challenged and treated with milonine at 2.0 mg/kg. Twenty-four hours later, the bronchoalveolar fluid, peripheral blood, and lungs were collected for cellular and molecular analysis. The milonine treatment decreased the cell migration (mainly neutrophils) to the alveoli, the pulmonary edema, and the cytokine levels (IL-1β, IL-6, TNF-α). The systemic IL-6 level was also reduced. The milonine docking analysis demonstrated hydrophobic interaction at TLR4/MD2 groove with Ile124 and Phe126 amino acids. Indeed, the alkaloid downregulated the kinase-Akt and NF-κB through TLR4/MD2. Therefore, milonine is an effective inflammatory modulator being a potential molecule for the treatment of lung inflammation.
Sampling at Pampulha Reservoir in Minas Gerais State in August of 2012 found Moina macrocopa, until now reported for South America only in a temporary pond in Rio de Janeiro State, Brazil and similar ...environments in South America. The most recent inventory of cladocerans for Minas Gerais State did not mention this species, indicating recent appearance. Pampulha Reservoir is a eutrophic medium-sized reservoir with an area of 1.82km^sup 2^ and mean depth of 5.0m, corresponding to the depth of the sampling site. Recent studies on this reservoir have reported Moina micrura among the Moinidae. In August of 2012, specimens of Moina macrocopa were also found in the central compartment of the reservoir, representing around 1% of the cladocerans. Samplings carried out in 2013, showed fluctuations in its numerical densities, with an increase in April and reduction in May and June, suggesting an initial colonisation process for the species. On the other hand, Pampulha reservoir, besides being eutrophic, is highly contaminated by industrial effluents.
The Ibirité reservoir is an urban and eutrophic environment, with regular occurrences of cyanobacteria blooms. The reservoir is warm monomict and remains stratified most of the year, circulating in ...the dry season (winter). During the hydrological cycle of October/07 to October/08 there were four scenarios with different environmental conditions, which influenced the structure of the zooplankton community, as confirmed in a previous study. Changes in the zooplankton community structure between the scenarios were studied, aiming at analyzing the stability and persistence of this community. The Spearman's coefficient of correlation was used to measure the stability; the persistence was evaluated through a cluster analysis and changes in community composition were estimated by the "temporal" β diversity index. Considering the distribution patterns of abundance, the community was stable only in the transition between scenarios 1 and 2 (n = 30, r = 0.71, p = 0.00001), when there were no cyanobacteria blooms. The persistence of zooplankton between the scenarios was low, showing a distinct species composition for each scenario. The highest variations in species composition, observed by the values of temporal β diversity index, were the transitions between scenarios 3-0 (1.45) and 0-1 (1.05), and the lowest variations occurred in the transition between scenarios 1-2 (0.57). The results suggest that the cyanobacteria blooms at Ibirité reservoir are be acting as "selective filters", and are, thus, disturbances with sufficient ability to change the structure of the zooplankton community.
The introduction of species has become an important problem for biodiversity and natural ecosystem conservation. The lake system of the middle Rio Doce (MG, Brazil) comprises c. 200 lakes at various ...conservation states, of which 50 are located within the Rio Doce State Park (PERD). Previous studies had verified several of these lakes suffered non-native fishes introductions and the presence of these species needs for the implementation of actions aiming at not only their control but also the preservation of the native species. This study discusses the effects of non-native fish species in the largest conservation unit of Atlantic Forest in Minas Gerais, southeast of Brazil, using data from 1983 to 2010 distributed as follow: data prior to 2006 were obtained from previous studies, and data from September 2006 to July 2010 were obtained in Lake Carioca at four sampling stations using gillnets, seine nets and sieve. A total of 17 fish species was collected (2006-2010) of which five were introduced species. Among the small to medium size native species (30 to 2000 mm standard length) seven had disappeared, two are new records and one was recaptured. The non-native species Cichla kelberi (peacock bass) and Pygocentrus nattereri (red piranha) are within the most abundant captured species. Integrated with other actions, such as those preventing new introductions, a selective fishing schedule is proposed as an alternative approach to improve the conservation management actions and the local and regional biodiversity maintenance.
The present study deals with the ecological impacts of the introduction of two alien species of piscivorous fish in several lakes of the Middle Rio Doce lake district in Minas Gerais, Brazil. It was ...demonstrated that these effects were not restricted only to the fish community. The introduction of the predatory red piranha Pygocentrus nattereri and the tucunaré Cichla cf. ocellaris caused not only a sharp decrease in the number of native fish species, but also major shifts in other trophic levels. Just after the fish were introduced, most lakes began to show conspicuous changes in phytoplankton species composition, in which Cyanophyceae gradually came to dominate. The zooplankton community lost several species, and in some cases, such as Lake Carioca, all the cladoceran species disappeared. On the other hand, invertebrate predators, represented by the dipteran Chaoboridae, boomed in the lake, with higher densities of exotic species, probably as a result of the 'ecological release' by reduction of the original fish fauna. There was a general trend of species loss in different trophic levels. All these changes are apparently associated with decreases in water quality. The present situation in these lakes demands new approaches to the management and conservation of these ecosystems.
Cladocerans are able to produce resting eggs inside a protective resistant capsule, the ephippium, that difficults the visualization of the resting eggs, because of the dark pigmentation. Therefore, ...before hatching experiments, methods to verify viable resting eggs in ephippia must be considered. This study aimed to evaluate the number of eggs per ephippium of Daphnia from two tropical aquatic ecosystems and the efficiency of some methods for decapsulating resting eggs. To evaluate the influence of methods on hatching rates, three different conditions were tested: immersion in sodium hypochlorite, manually decapsulated resting eggs and intact ephippia. The immersion in hypochlorite solution could evaluate differences in numbers of resting eggs per ephippium between the ecosystems studied. The exposure to sodium hypochlorite at a concentration of 2% for 20 minutes was the most efficient method for visual evaluation and isolation of the resting eggs. Hatching rate experiments with resting eggs not isolated from ephippia were underestimated (11.1 ± 5.0%), showing the need of methods to quantify and isolate viable eggs. There were no differences between the hatching rate of resting eggs submitted to hypochlorite solution (47.2 ± 7.34%) and manually decapsulated (53.7 ± 13.24%). However, the immersion in hypochlorite was a more efficient technique, faster and not requiring manual ability.
In order to verify changes in physical, chemical and biological features of Dom Helvécio Lake (South-East Brazil), this study compares previous and recent data obtained from limnological ...investigations over three decades. Plankton species composition and density together with environmental data from 1978, 1983, and during 1999 to 2006 showed changes driven by seasonal climatic forces or by anthropogenic causes. Changes in diversity are shown as a consequence of alternation of rainy and dry periods and introduction of exotic fish species. Finally, suggestions are made for improving conservation efforts in the area, through planned actions and monitoring programmes.
Behavioral responses are important in zooplankton species exposed to invertebrate predators. In a Brazilian natural lake, the ostracod Physocypria schubarti Farkas, 1958 is abundant, despite the ...presence of predatory Chaoborus Lichtenstein, 1800 larvae. This is intriguing as this predator controls several microcrustacean populations in nature. Therefore, we analysed the interactions between fourth instar Chaoborus larvae and ostracods of two body sizes in laboratory. We evaluated (1) the behaviour of P. schubarti during Chaoborus attacks, (2) the probability of Chaoborus larvae ingesting them during such interactions and (3) the prey survival and predator ingestion rates after 24 h. When attacked, ostracods of both sizes frequently ceased to move and passively sank in the water column. This anti-predation strategy ("akinesis" or "dead-man response") was observed in over 80% of the interactions involving physical contact. Surprisingly the probability of Chaoborus larvae eating prey that exhibited, or not, this reaction was close or equal to zero. After 24 h, over 92% of the prey survived and the ingestion rate of the chaoborids was practically nihil. Our results suggest that, although akinesis is a very common behaviour, additional features of P. schubarti may be as or more important in explaining its low vulnerability when in high spatial overlap with Chaoborus larvae.
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BFBNIB, DOBA, IZUM, KILJ, NMLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
The present study was carried out in Lake Dom Helvécio, in the state of Minas Gerais, with two main objectives: to demonstrate the contribution of the littoral zone, in order to better characterize ...zooplankton fauna; and to assess the distribution of zooplankton species in different habitats, i.e., the littoral zone with and without aquatic vegetation. The samples were collected in February and July 2006, throughout the littoral zone of the lake, in areas with and without aquatic vegetation. We identified a total of 188 species, of which 130 are new records for Lake Dom Helvécio. One hundred and eighty-four species were identified in the littoral zone with aquatic vegetation, and 117 in the zone with no vegetation. The higher zooplankton richness in areas of the littoral zone with aquatic vegetation can be related to the greater environmental heterogeneity. Compared to previous studies on the littoral zones of lakes along the middle River Doce, the present study expended greater sampling effort, and identified many more species. In relation to biological conservation, this study demonstrated the importance of the littoral zone for better characterization and conservation of the zooplankton fauna, especially when it is colonized by aquatic vegetation. Underestimating the richness of species may provide inaccurate data on the biota, as well as on the ecological conditions in an environment.
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