Hutchinson’s fundamental niche, defined by the physical and biological environments in which an organism can thrive in the absence of inter-species interactions, is an important theoretical concept in ecology. However, little is known about the overlap between the fundamental niche and the set of conditions species inhabit in nature, and about natural variation in fundamental niche shape and its change as species adapt to their environment. Here, we develop a custom-made dual gradient apparatus to map a cross-section of the fundamental niche for several marine bacterial species within the genus Vibrio based on their temperature and salinity tolerance, and compare tolerance limits to the environment where these species commonly occur. We interpret these niche shapes in light of a conceptual model comprising five basic niche shapes. We find that the fundamental niche encompasses a much wider set of conditions than those strains typically inhabit, especially for salinity. Moreover, though the conditions that strains typically inhabit agree well with the strains’ temperature tolerance, they are negatively correlated with the strains’ salinity tolerance. Such relationships can arise when the physiological response to different stressors is coupled, and we present evidence for such a coupling between temperature and salinity tolerance. Finally, comparison with well-documented ecological range in V. vulnificus suggests that biotic interactions limit the occurrence of this species at low-temperature—high-salinity conditions. Our findings highlight the complex interplay between the ecological, physiological and evolutionary determinants of niche morphology, and caution against making inferences based on a single ecological factor.
SummaryRecent ornithological surveys of humid forest remnants in the Serra da Ouricana near Boa Nova, southern Bahia, Brazil, revealed the existence of an as yet unnoticed montane Atlantic forest avifauna. Among the 220 species recorded, 27 represent range extensions of several hundred kilometres, several others were preceded only by single or a few old, disputed records from Bahia, and at least two are undescribed taxa. A portion of this avifauna has been recorded in other mountainous areas of interior Bahia (Chapada Diamantina, plateau of Maracas), where a complex vegetation mosaic that includes patches of humid forest is found.In addition to the two undescribed passerines, nine other threatened and thirteen near-threatened species have been recorded in the study area. Considered together with the adjoining and also highly endangered "mata-de-cipo", forest habitats in the Boa Nova area are probably the most neglected habitats in Brazil concerning bird conservation.Levantamentos ornitologicos recentemente feitos em remanescentes florestais umidos na Serra da Ouricana perto de Boa Nova, sul da Bahia, Brasil, revelaram a existencia nessa regiao de uma avifauna monticola da mata Atlantica. Entre as 220 especies registradas, estao 27 que tiveram sua area de distribuicao estendida por centenas de quilometros, muitas outras conhecidas da Bahia apenas atraves de registros antigos e contestados, alem de ao menos duas aves nao descritas. Parte dessa avifauna foi tambem registrada em outras areas montanhosas do interior da Bahia (Chapada Diamantina, Chapadao Maracas), onde se encontra um complexo mosaico de vegetacao que inclui manchas de floresta umida. Alem dos dois passaros nao descritos, outras nove especies ameacadas e treze quase-ameacadas foram registradas na area de estudo. Considerando-se em conjunto essa area com a vizinha "mata-de-cipo", tambem muito ameacada, pode-se dizer que os ambientes florestais na regiao de Boa Nova sao os habitats mais negligenciados em relacao a conservacao de aves no Brasil.
Refined fuels have considerable share of pollution of marine ecosystems. Gasoline is one of the most consumed fuel worldwide, but its effects on marine benthic primary producers are poorly investigated. In this study, Ulva lactuca was chosen as a biological model due to its cosmopolitan nature and tolerance to high levels and wide range of xenobiotics and our goal was to evaluate the effects of gasoline on ultrastructure and metabolism of that seaweed. The experimental design consisted of in vitro exposure of U. lactuca to four concentrations of gasoline (0.001%, 0.01%, 0.1%, and 1.0%, v/v) over 30 min, 1 h, 12 h, and 24 h, followed by cytochemical, SEM, and biochemical analysis. Increase in the number of cytoplasmic granules, loss of cell turgor, cytoplasmic shrinkage, and alterations in the mucilage were some of the ultrastructural alterations observed in thalli exposed to gasoline. Decrease in carotenoid and polyphenol contents, as well as increase of soluble sugars and starch contents were associated with the time of exposure to the xenobiotic. In combination, the results revealed important morphological and biochemical alterations in the phenotype of U. lactuca upon acute exposure to gasoline. This seaweed contain certain metabolites assigned as candidates to biomarkers of the environmental stress investigated and it is thought to be a promise species for usage in coastal ecosystems perturbation monitoring system. In addition, the findings suggest that U. lactuca is able to metabolize gasoline hydrocarbons and use them as energy source, acting as bioremediator of marine waters contaminated by petroleum derivatives.
Fossil fuels, e.g. gasoline and diesel oil, account for substantial share of the pollution that affects marine ecosystems. Environmental metabolomics is an emerging field that may help unravel the effect of these xenobiotics on seaweeds and provide methodologies for biomonitoring coastal ecosystems. In the present study, FTIR and multivariate analysis were used to discriminate metabolic profiles of Ulva lactuca after in vitro exposure to diesel oil and gasoline, in combinations of concentrations (0.001%, 0.01%, 0.1%, and 1.0% - v/v) and times of exposure (30min, 1h, 12h, and 24h). PCA and HCA performed on entire mid-infrared spectral window were able to discriminate diesel oil-exposed thalli from the gasoline-exposed ones. HCA performed on spectral window related to the protein absorbance (1700-1500cm) enabled the best discrimination between gasoline-exposed samples regarding the time of exposure, and between diesel oil-exposed samples according to the concentration. The results indicate that the combination of FTIR with multivariate analysis is a simple and efficient methodology for metabolic profiling with potential use for biomonitoring strategies.
Background/Aim: Glioblastomas (GBMs) are the most malignant primary brain tumor. New treatment strategies against the disease are urgently needed, as therapies are not completely efficient. In this study, we evaluated the antitumorigenic activity of the carotenoid fucoxanthin (Fx) on human GBM cells in vitro. Materials and Methods: GBM1 cell viability and proliferation was assessed by MTT reduction, Ki67 and single cell cloning assays. GBM1 migration and invasion were analyzed by wound healing and Transwell assays. Apoptosis and necrosis were analyzed by flow cytometry, and the mitochondrial membrane potential (ΔΨm) by the selective fluorescent dye tetramethylrhodamine ethyl ester. Cell morphology was analyzed through scanning electron microscopy and transmission electron microscopy. Fx anti-angiogenic effect was assessed by the CAM ex ovo assay. Results: Fx decreased cell viability in a concentration-dependent manner (40-100 μ M) in GBM1, A172 and C6 cell lines and was not cytotoxic to murine astrocytes. In addition, Fx inhibited the proliferation and clonogenic potential, and decreased migration and invasion of GBM1 cells. Furthermore, Fx induced apoptosis, loss of ΔΨm and ultrastructural alterations in GBM1. Fx-treated GBM1 cells-conditioned medium reduced the quail yolk membrane vascularity. Conclusion: Fx induces cytotoxicity, anti-proliferative, antiinvasive and anti-angiogenic effects on GBM1 cells.Gliomas are primary tumors that affect the central nervous system (CNS). The origin of glioma cells is not completely elucidated, and may derive from dedifferentiation of a mature cell type, glial progenitor cells or primitive neural stem cells (1). The primary malignant brain neoplasms global-gender incidence rate is approximately 2.6 per 100,000 for females and 3.7 per 100,000 for males, per year (2). Gliomas compose only 27% of all CNS primary neoplasms, however, it represents almost 80% of all malignant primary tumors that affect this system (3,4).Gliomas are histopathologically categorized by the World Health Organization (WHO) into different subtypes and grades (I to IV), as oligodendroglioma, oligoastrocytoma and astrocytoma. Grade IV is reserved for a subtype of astrocytoma, the glioblastoma (GBM) (5). GBM is the most malignant glioma and the most frequent primary cerebral tumor, with an incidence of 3.2 cases per 100,000 person/year 6799
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