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1.
Sci Total Environ ; 806(Pt 1): 150401, 2022 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-34562761

RESUMO

Microeukaryotes play a significant role in biogeochemical cycling and can serve as bioindicators of water quality in freshwater ecosystems. However, there is a knowledge gap on how freshwater microeukaryotic communities are assembled, especially that how terrestrial microeukaryotes influence freshwater microeukaryotic assemblages. Here, we used a combination of 18S rRNA gene amplicon sequencing and community-based microbial source tracking (MST) approaches (i.e., SourceTracker and FEAST) to assess the contribution of microeukaryotes from surrounding environments (i.e., soils, river sediments, swine wastewater, influents and effluents of decentralized wastewater treatment plants) to planktonic microeukaryotes in the main channel, tributaries and reservoir of a peri-urban watershed, China in wet and dry seasons. The results indicated that SAR (~ 49% of the total communities), Opithokonta (~ 34%), Archaeplastida (~ 9%), and Amoebozoa (~ 2%) were dominant taxa in the watershed. The community-based MST analysis revealed that sewage effluents (7.96 - 21.84%), influents (2.23 - 13.97%), and river sediments (2.56 - 11.71%) were the major exogenous sources of riverine microeukaryotes. At the spatial scale, the downstream of the watershed (i.e., main channel and tributaries) received higher proportions of exogenous microeukaryotic OTUs compared to the upstream reservoirs, while at the seasonal scale, the sewage effluents and influents contributed higher exogenous microeukaryotes to river water in wet season than in dry season. Moreover, the swine and domestic wastewater led to the presence of Apicomplexa in wet season only, implying rainfall runoff may enhance the spread of parasitic microeukaryotes. Taken together, our study provides novel insights into the immigration patterns of microeukaryotes and their dominant supergroups between terrestrial and riverine habitats.


Assuntos
Ecossistema , Rios , Animais , China , Aprendizado de Máquina , Plâncton , Suínos , Qualidade da Água
2.
Bioresour Technol ; 343: 126098, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34626764

RESUMO

Distinct microbial assemblages evolve in anaerobic digestion (AD) reactors to drive sequential conversions of organics to methane. The spatio-temporal development of three such assemblages (granules, biofilms, planktonic) derived from the same inoculum was studied in replicated bioreactors treating long-chain fatty acids (LCFA)-rich wastewater at 20 °C at hydraulic retention times (HRTs) of 12-72 h. We found granular, biofilm and planktonic assemblages differentiated by diversity, structure, and assembly mechanisms; demonstrating a spatial compartmentalisation of the microbiomes from the initial community reservoir. Our analysis linked abundant Methanosaeta and Syntrophaceae-affiliated taxa (Syntrophus and uncultured) to their putative, active roles in syntrophic LCFA bioconversion. LCFA loading rates (stearate, palmitate), and HRT, were significant drivers shaping microbial community dynamics and assembly. This study of the archaea and syntrophic bacteria actively valorising LCFAs at short HRTs and 20 °C will help uncover the microbiology underpinning anaerobic bioconversions of fats, oil and grease.


Assuntos
Microbiota , Plâncton , Anaerobiose , Biofilmes , Reatores Biológicos , Ácidos Graxos , Metano , Esgotos
3.
An Acad Bras Cienc ; 93(suppl 3): e20200219, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34787168

RESUMO

The horizontal distribution of plankton communities in a subtropical mixed estuarine system over one tidal cycle was investigated. Hydrological and planktonic samples were obtained twice on 17 July 2007 in a transect with ten stations in the Babitonga Bay estuary, south Brazil (~26°S). Hydrological variables did not vary spatially or tidally during samplings. However, in the cluster analyses both phyto and zooplankton were structured according to their estuarine position and in the inner stations also by the tidal condition. Phytoplankton abundances were higher during flood tide in the inner estuary (max. 122,583 ind.L-1), where diatoms dominated, particularly Diploneis bombus. However, the density at ebb tide increased towards outer estuary (max. >100,000 ind.L-1) and flagellates, mostly Gymnodinium spp., became abundant. Zooplankton abundances were higher at intermediate stations during both tides (max. 13,691 ind.m-3). The innermost stations were dominated by the copepod Acartia tonsa, while in the outermost stations Temora turbinata and the polychaete larvae Loimia sp. dominated. The results demonstrate how variable the estuarine plankton horizontal structure can be over short time-scales even in mixed estuarine systems under relatively homogeneous conditions, highlighting the importance to consider such temporal scales for a more accurate understanding of the dynamics of these communities.


Assuntos
Copépodes , Plâncton , Animais , Estuários , Fitoplâncton , Zooplâncton
4.
Braz Dent J ; 32(3): 10-20, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34755784

RESUMO

The host defense response to microbial challenge emerging from the root canal system leads to apical periodontitis. The aim of this study was to evaluate the expression of inflammatory cytokines and Nitric Oxide (NO) by macrophages after interaction with Enterococcus faecalis in the: plankton and dislodged biofilm mode; intact biofilm mode stimulated by calcium hydroxide (CH), CH and chlorhexidine (CHX) or Triple Antibiotic Paste (TAP). For this purpose, culture of macrophages from monocytes in human peripheral blood (N=8) were exposed to the different modes of bacteria for 24 hours. Subsequently, the cytokines, such as, Tumor Necrotic Factor- alfa (TNF-α), interleukin (IL)-1ß, IL-6, IL-10; and NO were quantified by Luminex xMAP and Greiss reaction, respectively. In addition to the potential therapeutic effects of the intracanal medication, their antimicrobial activity against Enterococcus faecalis biofilm were also tested in vitro by confocal microscopy. The experiments` data were analyzed by the Kruskal-Wallis test with the Dunn post hoc test (α < 0.05). Bacteria in dislodged biofilm mode were shown to be more aggressive to the immune system than bacteria in plankton mode and negative control, inducing greater expression of NO and TNF-α. Relative to bacteria in intact biofilm mode, the weakest antimicrobial activity occurred in Group CH. In Groups CH/CHX and TAP the percentage of dead bacteria was significantly increased to the same extent. Interestingly, the biofilm itself did not induce the release of pro-inflammatory cytokines - except for NO - while the biofilm treated with TAP and CH based pastes enhanced the levels of IL-6 and TNF-α; and IL-1 ß, respectively. In contrast, the levels of a potent anti-inflammatory (IL-10) were increased in Group TAP.


Assuntos
Biofilmes , Plâncton , Antibacterianos , Bactérias , Hidróxido de Cálcio , Clorexidina , Enterococcus faecalis , Humanos , Irrigantes do Canal Radicular
5.
Front Cell Infect Microbiol ; 11: 722499, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34722331

RESUMO

Leucocyte- and platelet rich fibrin (L-PRF) is an autologous biomaterial used in regenerative procedures. It has an antimicrobial activity against P. gingivalis although the mechanism is not fully understood. It was hypothesized that L-PRF exudate releases hydrogen peroxide and antimicrobial peptides that inhibit P. gingivalis growth. Agar plate and planktonic culture experiments showed that the antimicrobial effect of L-PRF exudate against P. gingivalis was supressed by peroxidase or pepsin exposure. In developing multi-species biofilms, the antimicrobial effect of L-PRF exudate was blocked only by peroxidase, increasing P. gingivalis growth with 1.3 log genome equivalents. However, no effect was shown on other bacteria. Pre-formed multi-species biofilm trials showed no antimicrobial effect of L-PRF exudate against P. gingivalis or other species. Our findings showed that L-PRF exudate may release peroxide and peptides, which may be responsible for its antimicrobial effect against P. gingivalis. In addition, L-PRF exudate had an antimicrobial effect against P. gingivalis in an in vitro developing multi-species biofilm.


Assuntos
Anti-Infecciosos , Fibrina Rica em Plaquetas , Anti-Infecciosos/farmacologia , Biofilmes , Exsudatos e Transudatos , Projetos Piloto , Plâncton , Porphyromonas gingivalis
6.
Environ Sci Technol ; 55(22): 15456-15465, 2021 11 16.
Artigo em Inglês | MEDLINE | ID: mdl-34724376

RESUMO

Sinking particulate organic matter (POM) is a primary component of the ocean's biological carbon pump that is responsible for carbon export from the surface to the deep sea. Lipids derived from plankton comprise a significant fraction of sinking POM. Our understanding of planktonic lipid biosynthesis and the subsequent degradation of lipids in sinking POM is based on the analysis of bulk samples that combine many millions of plankton cells or dozens of sinking particles, which averages out natural heterogeneity. We developed and applied a nanoflow high-performance liquid-chromatography electrospray-ionization high-resolution accurate-mass mass spectrometry lipidomic method to show that two types of sinking particles─marine snow and fecal pellets─collected in the western North Atlantic Ocean have distinct lipidomes, providing new insights into their sources and degradation that would not be apparent from bulk samples. We pressed the limit of this approach by examining individual diatom cells from a single culture, finding marked lipid heterogeneity, possibly indicative of fundamental mechanisms underlying cell division. These single-cell data confirm that even cultures of phytoplankton cells should be viewed as mixtures of physiologically distinct populations. Overall, this work reveals previously hidden lipidomic heterogeneity in natural POM and phytoplankton cells, which may provide critical new insights into microscale chemical and microbial processes that control the export of sinking POM.


Assuntos
Lipidômica , Fitoplâncton , Oceanos e Mares , Plâncton , Água do Mar
7.
Environ Sci Technol ; 55(22): 15476-15483, 2021 11 16.
Artigo em Inglês | MEDLINE | ID: mdl-34738802

RESUMO

Methylmercury (CH3Hg+, MMHg) in the phytoplankton and zooplankton, which form the bottom of marine food webs, is a good predictor of MMHg in top predators, including humans. Therefore, evaluating the potential exposure of MMHg to higher trophic levels (TLs) requires a better understanding of relationships between MMHg biomagnification and plankton dynamics. In this study, a coupled ecological/physical model with 366 plankton types of different sizes, biogeochemical functions, and temperature tolerance is used to simulate the relationships between MMHg biomagnification and the ecosystem structure. The study shows that the MMHg biomagnification becomes more significant with increasing TLs. Trophic magnification factors (TMFs) in the lowest two TLs show the opposite spatial pattern to TMFs in higher TLs. The low TMFs are usually associated with a short food-chain length. The less bottom-heavy trophic pyramids in the oligotrophic oceans enhance the MMHg trophic transfer. The global average TMF is increased from 2.3 to 2.8 in the warmer future with a medium climate sensitivity of 2.5 °C. Our study suggests that if there are no mitigation measures for Hg emission, MMHg in the high-trophic-level plankton is increased more dramatically in the warming future, indicating greater MMHg exposure for top predators such as humans.


Assuntos
Compostos de Metilmercúrio , Bioacumulação , Ecossistema , Monitoramento Ambiental , Humanos , Plâncton
8.
Zootaxa ; 5039(4): 479-494, 2021 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-34811067

RESUMO

In order to complete the information related to the little studied deep-sea planktonic fauna of western Mexico, samples from a wide depth range (surface to 1550 m depth) were obtained using different gear. Six species and 108 individuals of hyperiid amphipods of the family Amphithyridae were collected at 26 localities, including a new species of Amphithyropsis Zeidler, 2016, which is herein described based on an adult male and a gravid female. Other species include Amphithyrus bispinosus Claus, 1879, the most abundant and frequently collected species (70 specimens at 17 localities), A. muratus Volkov, 1982 (11 specimens at 8 localities), A. sculpturatus Claus, 1879 (14 specimens at 7 localities), Paralycaea gracilis Claus, 1879 (10 specimens from 6 localities), and P. hoylei Stebbing, 1888 (one specimen from one locality). Worldwide and regional distributions are provided for each species.


Assuntos
Anfípodes , Animais , Feminino , Masculino , México , Plâncton
9.
Artigo em Inglês | MEDLINE | ID: mdl-34769984

RESUMO

The Western Pacific is the most oligotrophic sea on Earth, with numerous seamounts. However, the plankton diversity and biogeography of the Western Pacific in general and the seamount regions in particular remains largely unexplored. In this project, we quantitatively analyzed the composition and distribution patterns of plankton species in the Western Pacific seamount regions by applying metabarcoding analysis. We identified 4601 amplicon sequence variants (ASVs) representing 34 classes in seven protist phyla/divisions in the Western Pacific seamount regions, among which Dinoflagellata was by far the most dominant division. Among the 336 annotated phytoplankton species (including species in Dinoflagellata), we identified 36 harmful algal bloom (HAB) species, many of which displayed unique spatial distribution patterns in the Western Pacific seamount regions. This study was the first attempt in applying ASV-based metabarcoding analysis in studying phytoplankton and HAB species in the Western Pacific seamount regions, which may facilitate further research on the potential correlation between HABs in the Western Pacific seamount regions and coastal regions.


Assuntos
Dinoflagelados , Proliferação Nociva de Algas , Planeta Terra , Fitoplâncton/genética , Plâncton/genética
10.
Water Res ; 206: 117744, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34653795

RESUMO

Electrostimulated hydrolysis acidification (eHA) has been used as an efficient biological pre-treatment of refractory industrial wastewater. However, the effects of electrostimulation on the function and assembly of planktonic anaerobic sludge microbial communities are poorly understood. Using 16S rRNA gene and metagenomic sequencing, we investigated planktonic sludge microbial community structure, composition, function, assembly, and microbial interactions in response to electrostimulation. Compared with a conventional hydrolysis acidification (HA) reactor, the planktonic sludge microbial communities selected by electrostimulation promoted biotransformation of the azo dye Alizarin Yellow R. The taxonomic and functional structure and composition were significantly shifted upon electrostimulation with azo dyes degraders (e.g. Acinetobacter and Dechloromonas) and electroactive bacteria (e.g. Pseudomonas) being enriched. More microbial interactions between fermenters and decolorizing and electroactive bacteria, as well as fewer interactions between different fermenters evolved in the eHA microbial communities. Moreover, the decolorizing bacteria were linked to the higher abundance of genes encoding for azo- and nitro-reductases and redox mediator (e.g. ubiquinone) biosynthesis involved in the transformation of azo dye. Microbial community assembly was more driven by deterministic processes upon electrostimulation. This study offers new insights into the effects of electrostimulation on planktonic sludge microbial community function and assembly, and provides a promising strategy for the manipulation of anaerobic sludge microbiomes in HA engineering systems.


Assuntos
Microbiota , Esgotos , Reatores Biológicos , Plâncton , RNA Ribossômico 16S/genética , Águas Residuárias
11.
Eur J Protistol ; 81: 125835, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34715455

RESUMO

Thecadinium is a morphologically heterogenous marine benthic genus. Its polyphyly has been discussed. After redefinition of the sensu stricto genus, sensu lato taxa now need reclassification. Heterotrophic, morphologically closely related species were studied in detail. Molecular phylogenetic data for three of the four known species (T. ornatum, T. acanthium, T. ovatum) and new morphological data were obtained, leading to an emended thecal plate pattern, including the presence of an apical pore complex and an additional hypothecal plate. The results confirm the close relationship of the species and justify the description of Carinadinium gen. nov., characterized by the tabulation APC 3/4' 1/0a 6″ 6c 5s 5‴ 2'‴, an epithecal plate of special morphology, an apical flange, a ventral pore, antapical appendages, a descending cingulum and lateral cell flattening. The genus can be separated into two sub-clades, one with a third precingular 'dimple'-plate, four apical and no anterior intercalary plates and the other with a 'multi-pimple'-plate as third precingular or its homolog plate, three apical and one anterior intercalary plate. Carinadinium is phylogenetically related to the planktonic genera Protoceratium, Pentaplacodinium, and Ceratocorys (family Protoceratiaceae), and clearly belongs into the order Gonyaulacales, but with uncertain family affiliation.


Assuntos
Dinoflagelados , Dinoflagelados/genética , Filogenia , Plâncton
12.
Sensors (Basel) ; 21(20)2021 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-34695933

RESUMO

Variations in the quantity of plankton impact the entire marine ecosystem. It is of great significance to accurately assess the dynamic evolution of the plankton for monitoring the marine environment and global climate change. In this paper, a novel method is introduced for deep-sea plankton community detection in marine ecosystem using an underwater robotic platform. The videos were sampled at a distance of 1.5 m from the ocean floor, with a focal length of 1.5-2.5 m. The optical flow field is used to detect plankton community. We showed that for each of the moving plankton that do not overlap in space in two consecutive video frames, the time gradient of the spatial position of the plankton are opposite to each other in two consecutive optical flow fields. Further, the lateral and vertical gradients have the same value and orientation in two consecutive optical flow fields. Accordingly, moving plankton can be accurately detected under the complex dynamic background in the deep-sea environment. Experimental comparison with manual ground-truth fully validated the efficacy of the proposed methodology, which outperforms six state-of-the-art approaches.


Assuntos
Plâncton , Procedimentos Cirúrgicos Robóticos , Mudança Climática , Ecossistema , Oceanos e Mares
13.
Glob Chang Biol ; 27(23): 6294-6306, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34520606

RESUMO

Global environmental changes are causing widespread nutrient depletion, declines in the ratio of dissolved inorganic nitrogen (N) to total phosphorus (DIN:TP), and increases in both water temperature and terrestrial colored dissolved organic carbon (DOC) concentration (browning) in high-latitude northern lakes. Declining lake DIN:TP, warming, and browning alter the nutrient limitation regime and biomass of phytoplankton, but how these stressors together affect the nutritional quality in terms of polyunsaturated fatty acid (PUFA) contents of the pelagic food web components remains unknown. We assessed the fatty acid compositions of seston and zooplankton in 33 lakes across south-to-north and boreal-to-subarctic gradients in Sweden. Data showed higher lake DIN:TP in the south than in the north, and that boreal lakes were warmer and browner than subarctic lakes. Lake DIN:TP strongly affected the PUFA contents-especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)-in seston, calanoids, and copepods (as a group), but not in cladocerans. The EPA+DHA contents increased by 123% in seston, 197% in calanoids, and 230% in copepods across a lake molar DIN:TP gradient from 0.17 to 14.53, indicating lower seston and copepod nutritional quality in the more N-limited lakes (those with lower DIN:TP). Water temperature affected EPA+DHA contents of zooplankton, especially cladocerans, but not seston. Cladoceran EPA+DHA contents were reduced by ca. 6% for every 1°C increase in surface water. Also, the EPA, DHA, or EPA+DHA contents of Bosmina, cyclopoids, and copepods increased in lakes with higher DOC concentrations or aromaticity. Our findings indicate that zooplankton food quality for higher consumers will decrease with warming alone (for cladocerans) or in combination with declining lake DIN:TP (for copepods), but impacts of these stressors are moderated by lake browning. Global environmental changes that drive northern lakes toward more N-limited, warmer, and browner conditions will reduce PUFA availability and nutritional quality of the pelagic food web components.


Assuntos
Plâncton , Zooplâncton , Animais , Lagos , Valor Nutritivo , Fitoplâncton
14.
Nat Commun ; 12(1): 5226, 2021 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-34471105

RESUMO

Marine phytoplankton and zooplankton form the basis of the ocean's food-web, yet the impacts of climate change on their biodiversity are poorly understood. Here, we use an ensemble of species distribution models for a total of 336 phytoplankton and 524 zooplankton species to determine their present and future habitat suitability patterns. For the end of this century, under a high emission scenario, we find an overall increase in plankton species richness driven by ocean warming, and a poleward shift of the species' distributions at a median speed of 35 km/decade. Phytoplankton species richness is projected to increase by more than 16% over most regions except for the Arctic Ocean. In contrast, zooplankton richness is projected to slightly decline in the tropics, but to increase strongly in temperate to subpolar latitudes. In these latitudes, nearly 40% of the phytoplankton and zooplankton assemblages are replaced by poleward shifting species. This implies that climate change threatens the contribution of plankton communities to plankton-mediated ecosystem services such as biological carbon sequestration.


Assuntos
Biodiversidade , Aquecimento Global , Biologia Marinha , Plâncton/classificação , Animais , Regiões Árticas , Mudança Climática , Ecossistema , Cadeia Alimentar , Fitoplâncton , Temperatura , Zooplâncton
15.
Microbiome ; 9(1): 190, 2021 09 20.
Artigo em Inglês | MEDLINE | ID: mdl-34544488

RESUMO

BACKGROUND: Coastal aquatic ecosystems include chemically distinct, but highly interconnected environments. Across a freshwater-to-marine transect, aquatic communities are exposed to large variations in salinity and nutrient availability as tidal cycles create periodic fluctuations in local conditions. These factors are predicted to strongly influence the resident microbial community structure and functioning, and alter the structure of aquatic food webs and biogeochemical cycles. Nevertheless, little is known about the spatial distribution of metabolic properties across salinity gradients, and no study has simultaneously surveyed the sediment and water environments. Here, we determined patterns and drivers of benthic and planktonic prokaryotic and microeukaryotic community assembly across a river and tidal lagoon system by collecting sediments and planktonic biomass at nine shallow subtidal sites in the summer. Genomic and transcriptomic analyses, alongside a suite of complementary geochemical data, were used to determine patterns in the distribution of taxa, mechanisms of salt tolerance, and nutrient cycling. RESULTS: Taxonomic and metabolic profiles related to salt tolerance and nutrient cycling of the aquatic microbiome were found to decrease in similarity with increasing salinity, and distinct trends in diversity were observed between the water column and sediment. Non-saline and saline communities adopted divergent strategies for osmoregulation, with an increase in osmoregulation-related transcript expression as salinity increased in the water column due to lineage-specific adaptations to salt tolerance. Results indicated a transition from phosphate limitation in freshwater habitats to nutrient-rich conditions in the brackish zone, where distinct carbon, nitrogen and sulfur cycling processes dominated. Phosphorus acquisition-related activity was highest in the freshwater zone, along with dissimilatory nitrate reduction to ammonium in freshwater sediment. Activity associated with denitrification, sulfur metabolism and photosynthesis were instead highest in the brackish zone, where photosynthesis was dominated by distinct microeukaryotes in water (Cryptophyta) and sediment (diatoms). Despite microeukaryotes and archaea being rare relative to bacteria, results indicate that they contributed more to photosynthesis and ammonia oxidation, respectively. CONCLUSIONS: Our study demonstrates clear freshwater-saline and sediment-water ecosystem boundaries in an interconnected coastal aquatic system and provides a framework for understanding the relative importance of salinity, planktonic-versus-benthic habitats and nutrient availability in shaping aquatic microbial metabolic processes, particularly in tidal lagoon systems. Video abstract.


Assuntos
Microbiota , Plâncton , Ecossistema , Microbiota/genética , Nutrientes , Osmorregulação , Plâncton/genética , Rios
16.
Environ Sci Process Impacts ; 23(10): 1443-1457, 2021 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-34549767

RESUMO

Marine and freshwater microalgae belong to taxonomically and morphologically diverse groups of organisms spanning many phyla with thousands of species. These organisms play an important role as indicators of water ecosystem conditions since they react quickly and predictably to a broad range of environmental stressors, thus providing early signals of dangerous changes. Traditionally, microscopic analysis has been used to identify and enumerate different types of organisms present within a given environment at a given point in time. However, this approach is both time-consuming and labor intensive, as it relies on manual processing and classification of planktonic organisms present within collected water samples. Furthermore, it requires highly skilled specialists trained to recognize and distinguish one taxa from another on the basis of often subtle morphological differences. Given these restrictions, a considerable amount of effort has been recently funneled into automating different steps of both the sampling and classification processes, making it possible to generate previously unprecedented volumes of plankton image data and obtain an essential database to analyze the composition of plankton assemblages. In this review we report state-of-the-art methods used for automated plankton classification by means of digital microscopy. The computer-microscope system hardware and the image processing techniques used for recognition and classification of planktonic organisms (segmentation, shape feature extraction, pigment signature determination and neural network grouping) will be described. An introduction and overview of the topic, its current state and indications of future directions the field is expected to take will be provided, organizing the review for both experts and researchers new to the field.


Assuntos
Microalgas , Ecossistema , Microscopia , Plâncton , Água
17.
PLoS One ; 16(9): e0257961, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34570809

RESUMO

Bacterial communities colonized on submerged substrata are recognized as a key factor in the formation of complex biofouling phenomenon in the marine environment. Despite massive maritime activities and a large industrial sector in the nearshore of the Laccadive Sea, studies describing pioneer bacterial colonizers and community succession during the early-stage biofilm are scarce. We investigated the biofilm-forming bacterial community succession on three substrata viz. stainless steel, high-density polyethylene, and titanium over 15 days of immersion in the seawater intake area of a power plant, located in the southern coastal region of India. The bacterial community composition of biofilms and peripheral seawater were analyzed by Illumina MiSeq sequenced 16S rRNA gene amplicons. The obtained metataxonomic results indicated a profound influence of temporal succession over substrate type on the early-stage biofilm-forming microbiota. Bacterial communities showed vivid temporal dynamics that involved variations in abundant bacterial groups. The proportion of dominant phyla viz. Proteobacteria decreased over biofilm succession days, while Bacteroidetes increased, suggesting their role as initial and late colonizers, respectively. A rapid fluctuation in the proportion of two bacterial orders viz. Alteromonadales and Vibrionales were observed throughout the successional stages. LEfSe analysis identified specific bacterial groups at all stages of biofilm development, whereas no substrata type-specific groups were observed. Furthermore, the results of PCoA and UPGMA hierarchical clustering demonstrated that the biofilm-forming community varied considerably from the planktonic community. Phylum Proteobacteria preponderated the biofilm-forming community, while the Bacteroidetes, Cyanobacteria, and Actinobacteria dominated the planktonic community. Overall, our results refute the common assumption that substrate material has a decisive impact on biofilm formation; rather, it portrayed that the temporal succession overshadowed the influence of the substrate material. Our findings provide a scientific understanding of the factors shaping initial biofilm development in the marine environment and will help in designing efficient site-specific anti-biofouling strategies.


Assuntos
Biofilmes , Água do Mar/microbiologia , Microbiologia da Água , Organismos Aquáticos/genética , Bacteroidetes/genética , Índia , Plâncton , Polietileno , Reação em Cadeia da Polimerase , Centrais Elétricas , Proteobactérias/genética , RNA Ribossômico 16S/genética , Fatores de Tempo , Titânio
18.
Nat Commun ; 12(1): 4948, 2021 08 16.
Artigo em Inglês | MEDLINE | ID: mdl-34400630

RESUMO

Since the middle of the past century, the Western Antarctic Peninsula has warmed rapidly with a significant loss of sea ice but the impacts on plankton biodiversity and carbon cycling remain an open question. Here, using a 5-year dataset of eukaryotic plankton DNA metabarcoding, we assess changes in biodiversity and net community production in this region. Our results show that sea-ice extent is a dominant factor influencing eukaryotic plankton community composition, biodiversity, and net community production. Species richness and evenness decline with an increase in sea surface temperature (SST). In regions with low SST and shallow mixed layers, the community was dominated by a diverse assemblage of diatoms and dinoflagellates. Conversely, less diverse plankton assemblages were observed in waters with higher SST and/or deep mixed layers when sea ice extent was lower. A genetic programming machine-learning model explained up to 80% of the net community production variability at the Western Antarctic Peninsula. Among the biological explanatory variables, the sea-ice environment associated plankton assemblage is the best predictor of net community production. We conclude that eukaryotic plankton diversity and carbon cycling at the Western Antarctic Peninsula are strongly linked to sea-ice conditions.


Assuntos
Biodiversidade , Ciclo do Carbono , Camada de Gelo , Plâncton/fisiologia , Regiões Antárticas , Carbono/metabolismo , Diatomáceas , Ecossistema , Eucariotos , Microbiota , Plâncton/genética , Temperatura
19.
Molecules ; 26(16)2021 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-34443298

RESUMO

Naphthodianthrones such as fagopyrin and hypericin found mainly in buckwheat (Fagopyrum spp.) and St. John's wort (SJW) (Hypericum perforatum L.) are natural photosensitizers inside the cell. The effect of photosensitizers was studied under dark conditions on growth, morphogenesis and induction of death in Saccharomyces cerevisiae. Fagopyrin and hypericin induced a biphasic and triphasic dose response in cellular growth, respectively, over a 10-fold concentration change. In fagopyrin-treated cells, disruptions in the normal cell cycle progression were evident by microscopy. DAPI staining revealed several cells that underwent premature mitosis without budding, a striking morphological abnormality. Flow Cytometric (FC) analysis using a concentration of 100 µM showed reduced cell viability by 41% in fagopyrin-treated cells and by 15% in hypericin-treated cells. FC revealed the development of a secondary population of G1 cells in photosensitizer-treated cultures characterized by small size and dense structures. Further, we show that fagopyrin and the closely related hypericin altered the shape and the associated fluorescence of biofilm-like structures. Colonies grown on solid medium containing photosensitizer had restricted growth, while cell-to-cell adherence within the colony was also affected. In conclusion, the photosensitizers under dark conditions affected culture growth, caused toxicity, and disrupted multicellular growth, albeit with different efficiencies.


Assuntos
Antracenos/farmacologia , Corantes/farmacologia , Perileno/análogos & derivados , Fármacos Fotossensibilizantes/farmacologia , Plâncton/crescimento & desenvolvimento , Quinonas/farmacologia , Saccharomycetales/crescimento & desenvolvimento , Apoptose/efeitos dos fármacos , Ciclo Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Fluorescência , Morfogênese/efeitos dos fármacos , Perileno/farmacologia , Plâncton/efeitos dos fármacos , Saccharomycetales/citologia , Saccharomycetales/efeitos dos fármacos
20.
Water Res ; 203: 117524, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-34418642

RESUMO

The Dual Scripps Plankton Camera (DSPC) is a new approach for automated in-situ monitoring of phyto- and zooplankton communities based on a dual magnification dark-field imaging microscope. Here, we present the DSPC and its associated image processing while evaluating its capabilities in i) detecting and characterizing plankton species of different size and taxonomic categories and ii) measuring their abundance in both laboratory and field applications. In the laboratory, body size and abundance estimates by the DSPC significantly and robustly scaled with measurements derived by microscopy. In the field, a DSPC installed permanently at 3 m depth in Lake Greifensee (Switzerland) delivered images of plankton individuals, colonies, and heterospecific aggregates at hourly timescales without disrupting natural arrangements of interacting organisms, their microenvironment or their behavior. The DSPC was able to track the dynamics of taxa, mostly at the genus level, in the size range between ∼10 µm to ∼ 1 cm, covering many components of the planktonic food web (including parasites and potentially toxic cyanobacteria). Comparing data from the field-deployed DSPC to traditional sampling and microscopy revealed a general overall agreement in estimates of plankton diversity and abundances. The most significant disagreements between traditional methods and the DSPC resided in the measurements of zooplankton community properties. Our data suggest that the DSPC is better equipped to study the dynamics and demography of heterogeneously distributed organisms such as zooplankton, because high temporal resolution and continuous sampling offer more information and less variability in taxa detection and quantification than traditional sampling. Time series collected by the DSPC depicted ecological succession patterns, algal bloom dynamics and diel fluctuations with a temporal frequency and morphological resolution that was never observed by traditional methods. Access to high frequency, reproducible and real-time data of a large spectrum of the planktonic ecosystem expands our understanding of both applied and fundamental plankton ecology. We conclude the DSPC is robust for both research and water quality monitoring and suitable for stable long-term deployments.


Assuntos
Lagos , Plâncton , Animais , Ecossistema , Humanos , Fitoplâncton , Zooplâncton
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