The accumulation of exopolysaccharides (EPS) produced by microorganisms occurs in the presence of excess substrate and limiting conditions of elements that are essential to growth, such as nitrogen, phosphorus, sulfur, and magnesium. The presence of EPS produced by bacterial cells contributes to slime colonies formation in solid medium and increased viscosity in liquid medium. This paper proposes an alternative method for screening EPS-producing lactic acid bacteria using solid medium-containing discs of filter paper that are saturated with active cultures. The screening was carried out under different culture conditions varying the type of sugar, pH, and temperature. EPS production was visualized by the presence of mucoid colonies on the discs, which was confirmed by the formation of a precipitate when part of this colony was mixed with absolute alcohol. The established conditions for obtaining a high number of isolates producing EPS were 10% sucrose, pH 7.5 and 28 ºC. This method proved to be effective and economical because several strains could be tested on the same plate, with immediate confirmation.
The unprecedented size of the human population, along with its associated economic activities, has an ever‐increasing impact on global environments. Across the world, countries are concerned about the growing resource consumption and the capacity of ecosystems to provide resources. To effectively conserve biodiversity, it is essential to make indicators and knowledge openly available to decision‐makers in ways that they can effectively use them. The development and deployment of tools and techniques to generate these indicators require having access to trustworthy data from biological collections, field surveys and automated sensors, molecular data, and historic academic literature. The transformation of these raw data into synthesized information that is fit for use requires going through many refinement steps. The methodologies and techniques applied to manage and analyze these data constitute an area usually called biodiversity informatics. Biodiversity data follow a life cycle consisting of planning, collection, certification, description, preservation, discovery, integration, and analysis. Researchers, whether producers or consumers of biodiversity data, will likely perform activities related to at least one of these steps. This article explores each stage of the life cycle of biodiversity data, discussing its methodologies, tools, and challenges. This article is categorized under: Algorithmic Development > Biological Data Mining
Camamu Bay is a shallow estuarine system, and its circulation pattern is governed by tidal forcing. The system is formed by four sectors including the main channel and three hydrodynamic regions, delimited by the influence of the five tributaries. Water samples were collected in two different pluviometric periods (dry and rainy), at nine sampling points over the three hydrodynamic regions, and at a mooring (13°52 0 27.42 00 S, 38°57 0 46.19 00 W), in the main channel, where samples were collected every 3 h over cycles of spring tides. At each sampling station, physicochemical variables were measured and water samples were collected for analysis of dissolved inorganic nutrients and chlorophyll a, composition and cell density studies of microphytoplankton. A total of 201 taxa were identified, and the great majority of the taxa were from the marine environment. The taxonomic composition varied between the hydrodynamic regions, with greater chainforming diatom richness, in the two study periods. Although the highest concentration of dissolved inorganic nutrients was observed in the rainy period, microphytoplankton cell density did not increase in this period. The patterns of the estuarine phytoplankton community in tropical oligotrophic systems are still little known when compared to the temperate regions. Camamu Bay is one of the last known areas in the tropical South Atlantic, and this study confirms its oligotrophic characteristics, based on abiotic and biotic conditions. We highlighted the importance of knowledge of pristine coastal systems as a tool for the evaluation of anthropogenic changes in these areas.
This study assessed the species composition, distribution, and functional profiles of cyanobacteria in Camamu Bay, a tropical oligotrophic estuarine system on the northeast coast of Brazil, using shotgun metagenomic sequencing. Surface-water samples were evaluated in two different rainfall periods (rainy and dry seasons), at nine stations in the three hydrodynamic regions of the bay. At a fixed sampling station, on each season, samples were taken over a tidal cycle at 3-h intervals over 12 h. A total of 219 cyanobacterial taxa were identified, demonstrating a diverse community of freshwater, euryhaline, and marine cyanobacteria. The genera of greater relative abundance, Synechococcus and Prochlorococcus, corresponded to the picoplankton fraction. Although Camamu Bay has conspicuous marine characteristics, the contribution of freshwater during the rainy season caused variation in cyanobacteria community, with an increase in species richness. Due the high prevalence of Synechococcus (90% of the sequences), the functional analysis revealed only minor differences in gene content between the dry and rainy seasons. In both rainy and dry seasons, an increase in Prochlorococcus relative abundance occurred during high tide, demonstrating the tidal influence in the bay. The environmental characteristics of the bay provide niche conditions for a wide variety of cyanobacteria, including freshwater, euryhaline, and marine strains.
The genus Metadinophysis was proposed by Nie & Wang (1941) based on their description of the new species Metadinophysis sinensis Nie & Wang, from collections in Ching-lan Bay, Hainan Province, China. In addition to the Pacific Ocean, coastal waters of Japan, Thailand, and Vietnam, the genus was recorded for the southern coast of Myanmar (Su-Myat et al. 2012) and more recently in New Caledonia (Chomérat 2016). The present study constitutes the first record of Metadinophysis sinensis for the tropical Atlantic Ocean, from collections made in five coastal systems located in the coast of Bahia (13°01’30” S and 038°34’40” W, 13°52’44” S and 038°57’58” W), northeastern Brazil (Fig. 1).
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