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1.
J Environ Manage ; 301: 113822, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34607135

RESUMO

Restoration of submerged plants in eutrophic lakes can reduce nutrients and phytoplankton biomass in the water body. However, the effect of submerged plants on phytoplankton communities and their photosynthetic activity in situ are still poorly understood. Here, we studied the response of phytoplankton community structure and fluorescence parameters to different submerged plants coverage, the relationship of phytoplankton community and fluorescence parameters with submerged plants coverage and water physicochemical parameters were analysed in sampling area of Hangzhou West Lakes. The results showed that the coverage and biomass of submerged plants were negatively correlated with nitrogen and phosphorus contents in water body but positively correlated with total phenol content. The ratio of nitrogen to phosphorus in the study site changed greatly (32.25-124.54). In spring and summer, Oscillatoria and Leptolyngbya (Cyanophyta) were the dominant species, while in autumn and winter, the dominant species were Cyclotella (Chlorophyta), and Melosira and Cymbella (Bacillariophyta). Compared with Chlorophyta and Bacillariophyta, fluorescence parameters of Cyanophyta were more sensitive to total phosphorus, N:P ratio, total phenols, pH, and electric conductivity. Fluorescence parameters of Chlorophyta and Bacillariophyta were only affected by underwater light. Total phosphorus (TP) and N:P had a negative effect on the maximum photochemical electron yield of Cyanophyta. Furthermore, Cyanophyta was inhibited by total phenols from submerged plants. When phytoplankton were under stress, photochemical electron yield decreased significantly, whereas non-photochemical quenching increased. The structural equation model showed that the coverage of submerged plants might indirectly affect the fluorescence parameters of Cyanophyta by affecting nitrogen, phosphorus, and total phenol contents in the water body. These findings contribute to the understanding of the mechanisms underlying the impact of submerged plant restoration on phytoplankton community dynamics in subtropical eutrophic shallow lakes and provide a theoretical basis for the management of lakes.


Assuntos
Cianobactérias , Diatomáceas , China , Eutrofização , Lagos , Nitrogênio/análise , Fósforo/análise , Fitoplâncton , Estações do Ano
2.
Bioresour Technol ; 344(Pt A): 126117, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34653631

RESUMO

Fucoxanthin (Fx) has gained a growing attention due to the remarkable biological activities. The limited biomass of was the restrictive factor for Fx production in Phaeodactylum tricornutum. In this study, Laminaria japonica hydrolysate (LPH) with a low addition proportion of 1.5 ml/L, was proved to promote fucoxanthin accumulation and cell growth simultaneously. Fx topped at 27.9 mg/L after 10-d cultivation in the LPH group, with a biomass of 1.59 g/L and a Fx content of 17.55 mg/g. Three key plant hormones in LPH were screened responsible for promoting fucoxanthin accumulation. Transcriptomic analysis and qRT-PCR results showed that genes related to Fx formation were generally up- regulated. The study demonstrated that LPH addition was a feasible and efficient strategy to enhance production of fucoxanthin, facilitating the scale-up production of Fx in autotrophic culture.


Assuntos
Diatomáceas , Laminaria , Biomassa , Diatomáceas/genética , Xantofilas
3.
Chemosphere ; 289: 133240, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34896422

RESUMO

Until now, knowledge about the interactive effects of microplastics and environmental factors on primary producers is quite limited. In this work, a marine diatom (Phaeodactylum tricornutum) was exposed to polymethyl methacrylate (PMMA) microplastics at different salinities (25, 35, and 45‰) for 10 days in order to study their interactive effects. Results showed that growth of P. tricornutum was negatively affected by PMMA microplastics and salinity variation with a minimum EC50 value of 91.75 mg L-1. Photosynthetic activity of P. tricornutum was also inhibited by the two factors, and their interactive effects on chlorophyll fluorescence parameters (Fv/Fm and ΦPSII) were significant. In the algal cells, soluble protein accumulated, activities of two antioxidant enzymes changed, and malondialdehyde (MDA) content increased when this diatom was exposed to the microplastics at different salinities. These data would help to evaluate the risks of microplastics to primary producers under different environmental factors.


Assuntos
Diatomáceas , Microplásticos , Plásticos/toxicidade , Polimetil Metacrilato/toxicidade , Salinidade
4.
J Forensic Leg Med ; 85: 102298, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34896890

RESUMO

A diagnosis of drowning is not always possible based on the traditional autopsy findings. The most widely used ancillary methods are based on the detection of diatoms and other waterborne organisms in the organs of the systemic circulation by light microscope or polymerase chain reaction (PCR). One of the greatest concerns is sample contamination. Bone marrow is a favourable source because the compact bone protects the sample from water ingress in the case of advanced decay. In our pilot study, we aimed to adopt sternal bone marrow aspiration - which is a widely used technique in haematology - for postmortem sampling. Control experiments of non-drowning victims showed that cleaning the skin over the sternum can prevent external contamination. Sternal aspirate samples were taken from seven suspected drowning victims along with lung, spleen, and femoral bone marrow samples. All specimens were examined for the presence of diatoms by light microscope and Cyanobacteria-specific DNA by PCR. We were able to obtain bone marrow aspirates from all cases without complications. In four of the sternal samples both diatoms and cyanobacterial DNA were detected, while one additional sternum sample was tested positive with PCR, but no diatom shells were detectable. Sternal bone marrow aspiration is simple and quick, which can be performed at the beginning of an autopsy, minimizing the chance of contamination. We have shown that this sampling method can be adopted for postmortem diatom testing. This minimally invasive technique might be used in virtual autopsy (postmortem computed tomography, PMCT) settings without opening body cavities.


Assuntos
Cianobactérias , Diatomáceas , Afogamento , Afogamento/diagnóstico , Humanos , Pulmão , Projetos Piloto , Esterno
5.
Environ Pollut ; 295: 118670, 2022 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-34902529

RESUMO

Triphenyl phosphate (TPhP) has been widely detected in various environmental media, including seawater, threatening the survival of marine organisms, especially marine planktic algae that are directly exposed to contamination. However, the hazard potential of TPhP on marine algae has not been studied thoroughly and systematically. In this study, a marine diatom, Phaeodactylum tricornutum, was treated with three concentrations of TPhP (0.08, 0.4 and 0.8 mg/L), and after 24 h of exposure, population growth, ultrastructure, physiology and transcriptome changes were investigated. The results reflected that TPhP suppressed the population growth of algae in a concentration-dependent manner, and the 24-h EC50 value was 1.27 mg/L. At all test concentrations, P. tricornutum could absorb more than 70% of TPhP from seawater over 24 h. Ultrastructural observations suggested a distorted lamellar structure with higher TPhP treatments, and the contents of chlorophyll and its precursors were also altered, as were photosynthetic activities. Moreover, 0.8 mg/L TPhP decreased the mitochondrial membrane potential, induced ROS overproduction and disrupted the cell membrane permeability of algal cells. At the transcriptomic level, some differentially expressed genes were enriched in photosynthetic electron transport, carbon fixation, chlorophyll biosynthesis, the TCA cycle and mitochondrial glycolysis. Additionally, 0.8 mg/L TPhP inhibited lipid de novo biosynthesis, suggesting that it may target organelle membranes, thereby contributing to functional defects. Chloroplasts and mitochondria were interpreted to be the subcellular targets of TPhP in P. tricornutum. These data promote the understanding of the toxic action mode of TPhP toward marine diatoms.


Assuntos
Diatomáceas , Cloroplastos , Mitocôndrias , Organofosfatos
6.
Bioresour Technol ; 344(Pt B): 126260, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34728358

RESUMO

Fucoxanthin has multiple beneficial effects on human health. However, an efficient cultivation strategy for hyper-production of microalgae-based fucoxanthin has been seldom achieved. Here, an auto-controlled photobioreactor (PBR) installed internal light-emitting diodes illumination with adjustable spectra ratio was firstly used to culture Odontella aurita. The results showed that red light (RL) was more suitable for cell growth and fucoxanthin accumulation than blue light (BL) and white light. The biomass and fucoxanthin production were further promoted by optimizing the ratios of RL and BL, with 8:2 giving the highest productivities of 570 and 9.41 mg L-1 d-1, respectively, which is the highest fucoxanthin productivity ever reported under photoautotrophic cultivation. Pilot-scale cultivation demonstrated its promising feasibility in commercial fucoxanthin production. Our study represents a pioneering work of harnessing the PBR with internal illumination for hyper-production of microalgae-based fucoxanthin, and provides feasible strategies for high-efficient production of other value-added products in related species/strains.


Assuntos
Diatomáceas , Microalgas , Biomassa , Humanos , Luz , Fotobiorreatores , Xantofilas
7.
Bioresour Technol ; 344(Pt B): 126320, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34780906

RESUMO

A series of commercial powdered media (Cell-Hi F2P, JWP and WP) and a hydroponics medium (FloraMicroBloom) were investigated for the cultivation of P. tricornutum, and compared with f/2 (a commonly employed laboratory cultivation medium; costlier to scale). Cell-Hi JWP showed good performance characteristics including cost-effectiveness. Outdoor cultivation of P. tricornutum in an airlift photobioreactor, using Cell-Hi JWP in the United Kingdom (UK) during September and October (average daily temperature ranging between 8 and 18 °C and natural sunlight) was comparable to cultivation indoors under controlled temperature and lighting. A strong positive correlation between fucoxanthin and chlorophyll a content, and a weak inverse correlation between eicosapentaenoic (EPA) content and temperature were observed. Commensal bacterial counts revealed a sinusoidal growth profile with a change in community dominance from Halomonas sp. to Marinobacter sp. This investigation reveals for the first time that a multi-product approach can be adopted with P. tricornutum in a UK outdoor environment using commercially viable powdered media.


Assuntos
Diatomáceas , Microalgas , Clorofila A , Meios de Cultura , Fotobiorreatores , Reino Unido
8.
Environ Pollut ; 294: 118672, 2022 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-34896401

RESUMO

Nowadays, the ubiquitous distribution and increasing abundance of P+III in waterbodies have caused serious concerns regarding its bioavailability and potential toxicity. However, our knowledge on these issues is relatively limited. We addressed previously unknown effects of P+III on three dominate algae species i.e. Microcystic aeruginosa (M. aeruginosa), Chlorella pyrenoidesa (C. pyrenoidesa) and Cyclotella. sp in eutrophic waterbodies in China. Remarkable declines in biomass, specific growth rate and Chl-a of algae cells treated with 0.01-0.7 mg/L P+III as sole or an alternative P source were observed, indicating P+III had an inhibitory effect on the algal growth. Besides, the intracellular enzyme activities e.g superoxide dismutase (SOD) and malondialdehyde (MDA) were significantly increased with P+III stress. M. aeruginosa and Cyclotella. sp cells seemed to be more sensitive to P+III toxicity than C. pyrenoidesa since cell membrane suffered more serious stress and destruction. These findings combined, it confirmed P+III could not be utilized as bioavailable P, but had certain toxicity to the tested algae. It indicated that the increased P+III abundance in eutrophic waterbodies would accelerate the algal cell death, which could have a positive effect against algal blooms. Our results provide new insights into assessing the ecological risks of P+III in aquatic environments.


Assuntos
Chlorella , Diatomáceas , Microcystis , Fosfitos , Eutrofização , Malondialdeído
9.
Chemosphere ; 286(Pt 3): 131674, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34392200

RESUMO

The toxic effects of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) on the marine alga Skeletonema costatum were studied, including the population dynamics, chlorophyll fluorescence characteristics, pigment content, superoxide dismutase (SOD) activity, malondialdehyde (MDA) content and morphology. High doses (200-600 µg L-1) of BDE-47 significantly suppressed the population growth of S. costatum, with a 96 h EC50 value of 293 µg L-1. Photosynthetic parameters (Fv/Fm, rETRmax and ΦPSⅡ) of photosystem II (PSII) were significantly inhibited with increasing BDE-47 concentrations. The chlorophyll c (chl c) concentration was also inhibited by exposure to BDE-47. In contrast, chl a and carotenoid concentrations were elevated after exposure to high concentrations of BDE-47 for 72 and 96 h. The SOD activity was generally higher at concentrations of 100-600 µg L-1 than those of the control when the exposure time was less than 48 h. With increasing time, the SOD activity generally decreased, and significantly higher SOD activity only occurred in the treatment with high doses of BDE-47. High MDA contents occurred after exposure for 96 h in all BDE-47 treatments. With increasing BDE-47 concentrations, drastic deformation of the silicious valve and detachment of the strutted processes were found. In addition, drastic decreases in the BDE-47 concentration in culture medium indicated the bioaccumulation of BDE-47 by S. costatum. Our results revealed multiple responses of S. costatum to BDE-47 exposure, and indicated the potential risk of BDE-47 in the East China Sea based on these responses.


Assuntos
Antioxidantes , Diatomáceas , Clorofila , Éteres Difenil Halogenados/toxicidade , Fotossíntese , Dinâmica Populacional
10.
J Environ Manage ; 302(Pt A): 113939, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34678542

RESUMO

Phytoplankton play a crucial role in energy flow and carbon cycling in aquatic ecosystems; however, exploring the driving factors influencing phytoplankton, especially in heavily sediment-laden rivers, is challenging. We analyzed 704 samples from 44 sampling sites along the Yellow River to investigate the biogeographic, environmental, and anthropogenic impacts on the phytoplankton community composition. Using cluster analysis, we identified three different phytoplankton community compositions in Regions Ⅰ, Ⅱ, and Ⅲ, which were consistent with the three primary changes in the water-surface slope across the three regions. The sampling results showed that the Bacillariophyta primarily consisted of Navicula, Cyclotella, Synedra, Fragilaria, Gyrosigma, Diatoma, and Asterionella. In addition, representation by Chlorophyta was dominated by Chlamydomonas, Pandorina, Closteriopsis, and Closterium, while Phormidium was the dominant Cyanophyta genus. The variation partitioning results indicated that spatial factors (geographic distance) were the most important determinants of phytoplankton community succession. Additionally, our results highlighted that the influence of spatial and climatic factors on the succession of the phytoplankton community structure was much greater than that of the water quality. Compared to that in the free-flowing river, the phytoplankton biomass in the impoundment was much higher, and the phytoplankton community was dominated by Dinophyta, Chlorophyta, and Cyanophyta, primarily because of anthropogenic impacts. Based on the composition and biomass of phytoplankton communities in different regions, the phytoplankton community composition in the Yellow River was found to be primarily influenced by the erosion of the watershed and the inflow of tributaries rather than by limited in situ algae growth.


Assuntos
Diatomáceas , Fitoplâncton , China , Ecossistema , Monitoramento Ambiental , Rios , Estações do Ano
11.
Bioresour Technol ; 344(Pt A): 126210, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34715335

RESUMO

The aquaculture industry is a significant producer of highly nutritious food for the increasing global population. However, the wastewater generated from aquaculture ponds is an emerging global issue. The present study demonstrates the culturing of marine diatoms (Chaetoceros gracilis and Thalassiosira weissflogii) in different proportions of aquaculture wastewater (AQW) coupled with inductively coupled plasma nanosilica (ICP-SiO2) and further explores their biorefinery potential concomitant nutrient removal. Thalassiosira weissflogii showed maximum carbohydrate content (79.47 ± 0.21 mg g-1) in 10% and protein content (27.09 ± 0.21 mg g-1) in 30% AQW: ICP-SiO2. Chaetoceros gracilis showed maximum carbohydrate content (91.64 ± 0.11 mg g-1) in 50% and protein content (27.75 ± 0.05 mg g-1) in 10% AQW: ICP-SiO2 respectively. Additionally, Chaetoceros gracilis showed maximum nitrate uptake in 30%, phosphate in 50%, and ammonia in 50% AQW: ICP-SiO2. While Thalassiosira weissflogii showed maximum nitrate, phosphate, and ammonia removal efficiency in 50%, 50%, and 10% AQW: ICP-SiO2 respectively. The study draws attention towards the utilization of diatoms in AQW treatment, aquafeed potential thus imparting a global circular bioeconomy.


Assuntos
Diatomáceas , Aquicultura , Lagoas , Dióxido de Silício , Águas Residuárias
12.
Micron ; 152: 103178, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34801958

RESUMO

Anti-diatom testing is a basic method to evaluate the anti-fouling performance of coatings. Many existing results of anti-diatom performances are evaluated based on their attachment number or coverage area, ignoring the influence of the crawling and adhesion behavior of diatoms on the analysis results. Here, a Folium Sennae-like film with multiple structural units was prepared by considering the influence of diatom attachment behaviors on the analysis results. The anti-diatom performances of different parts (divided and called four parts: edge, surface, cross striation, and vertical pattern) on the Folium Sennae-like film were evaluated using the counting and area methods. Obviously, the anti-diatom performance of the Folium Sennae-like film was superior to that of epoxy resin without structure. Under equal areas, the average numbers of diatoms on the cross striation and the vertical pattern were similar to the surface. It was found that the attachment behavior of Halamphora sp. is affected by microstructure units, rather than the combined structure of which the scale is much larger than that of diatoms. Meanwhile, the average attachment area for the unit number of diatoms was calculated. The diatom attachment area without microstructure, surface, cross striation, or vertical pattern was 81.751, 106.950, 73.904, and 84.376 µm2, respectively. Moreover, the static and dynamic motion behaviors of Halamphora sp. were studied, and the theory for Halamphora sp. attachment was modeled in three dimensions. The variable morphology of Halamphora sp. lead to inaccurate results for diatom analyses based on the counting and area methods, which is summarized here. This study discusses the evaluation method of coatings by anti-diatom performance, further promoting the research of diatoms in the field of antifouling.


Assuntos
Diatomáceas , Folhas de Planta
13.
Sci Total Environ ; 810: 152366, 2022 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-34915010

RESUMO

Mediterranean climate river systems are among the most threatened ecosystems worldwide, due to a long history of anthropogenic impacts and alien invasive species introductions. Many of such rivers naturally exhibit a non-perennial flow regime, with distinct seasonal, inter-annual and spatial heterogeneity. The present study seeks to detect diatom community patterns and to understand the processes that cause these structures in an Austral Mediterranean river system among different months and river sections. In general, most environmental variables showed an increasing trend downstream for both months, with the exception of pH, dissolved oxygen, PO43- and substrate embeddedness, which decreased downstream. A total of 110 diatom species between the two study months (October - 106 taxa; January - 78 taxa) were identified, dominated by 30 species with at least >2% abundance. Diatom community structure differed significantly across river zones, while no significant differences were observed between the study months. A boosted regression trees model showed that B (43.3%), Cu (20.8%), Fe (3.4%) and water depth (3.2%) were the most significant variables structuring diatoms. Diatom species communities reflected environmental variables (i.e., sediment and water chemistry) in this Mediterranean climate river system, as sediment metals such as B, Cu and Fe were found to be important in structuring diatom communities. Biotic influences from fish communities had little effect on diversity, but shifted diatom community structure. Therefore, the current study highlights how river systems have complex interactions that play an important role in determining diatom species composition.


Assuntos
Diatomáceas , Animais , Ecossistema , Monitoramento Ambiental , Rios
14.
Chemosphere ; 287(Pt 2): 131771, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34509003

RESUMO

Water-lifting aerators (WLAs) were often deployed in reservoirs to achieve artificial mixing (WLA activation) and induced (natural) mixing (early occurrence of complete natural mixing after WLA deactivation) for water quality improvement. Here, the mechanisms controlling phytoplankton growth via artificial and induced mixing were explored using a combination of taxonomic and functional classifications based on two-year monitoring data (i.e., non-operational and operational years of the WLAs). Artificial mixing resulted in a decrease of 99.2 % in phytoplankton cell density compared to that of the non-operational year, which continuously diminished to (3.06 ± 0.59) × 106 cells/L during induced mixing. The succession of phytoplankton structure in taxonomic and functional classification levels changed from Cyanobacteria to Chlorophyta and Bacillariophyta, from groups F, J, H1, and LM to A and X1, respectively, by comparison of the non-operational and operational years. Decreases in surface water temperature, total phosphorus concentration, and light availability, and increases in mixing depth via artificial and induced mixing were responsible for phytoplankton control, especially for cyanobacterial blooms, depending on a shift in phytoplankton composition from large or colonial, low surface to volume (S/V) to small, high S/V genera. Artificial and induced mixing also improved the trophic/ecological status of the reservoir, from "hyper-eutrophic and bad level" to "light-eutrophic and excellent level", based on an assessment of the trophic level index (TLI) and phytoplankton assemblage (Q) index. This study demonstrates that the suitable combination of artificial and induced mixing plays a crucial role in the maintenance and extension of healthy ecosystems in reservoirs.


Assuntos
Diatomáceas , Água Potável , China , Ecossistema , Eutrofização , Fitoplâncton , Estações do Ano , Qualidade da Água
15.
Sci Total Environ ; 803: 149894, 2022 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-34525756

RESUMO

With the growing demand of assessing the ecological status, there is the need to fully understand the relationship between the planktic diversity and the environmental factors. Species richness and Shannon index have been widely used to describe the biodiversity of a community. Besides, we introduced the first ordination value from non-metric multidimensional scaling (NMDS) as a new index to represent the community similarity variance. In this study, we hypothesized that the variation of diatom community in rivers in an agricultural area was influenced by hydro-chemical variables. We collected daily mixed water samples using ISCO auto water samplers for diatoms and for water-chemistry analysis at the outlet of a lowland river for a consecutive year. An integrated modeling was adopted including random forest (RF) to decide the importance of the environmental factors influencing diatoms, generalized linear models (GLMs) combined with 10-folder cross validation to analyze and predict the diatom variation. The hierarchical analysis highlighted antecedent precipitation index (API) as the controlling hydrological variable while water temperature, Si2+ and PO4-P as the main chemical controlling factors in our study area. The generalized linear models performed better prediction for Shannon index (R2 = 0.44) and NMDS (R2 = 0.51) than diatom abundance (R2 = 0.25) and species richness (R2 = 0.25). Our findings confirmed that Shannon index and the NMDS as an index showed good performance in explaining the relationship between stream biota and its environmental factors and in predicting the diatom community development based on the hydro-chemical predictors. Our study showed and highlighted the important hydro-chemical factors in the agricultural rivers, which could contribute to the further understanding of predicting diatom community development and could be implemented in the future water management protocol.


Assuntos
Diatomáceas , Biodiversidade , Monitoramento Ambiental , Hidrologia , Rios
16.
Chimia (Aarau) ; 75(12): 1052-1053, 2021 Dec 22.
Artigo em Inglês | MEDLINE | ID: mdl-34920779

RESUMO

When he introduced the concept of atomic weights at the beginning of the 19th Century CE, John Dalton assumed that water had the formula HO. This assumption resulted in a half century of confusion - partly because on a scale of H = 1, he defined the atomic weights O = 8 and C = 6, and partly because elements that could exhibit variable valency appeared to possess different atomic (or rather equivalent) weights. The correction of the formula of water, together with the recognition of the diatomic nature of the gases hydrogen and oxygen, were formalized following the Karlsruhe congress of 1861 and allowed the establishment of the 'modern' and consistent atomic weights.


Assuntos
Diatomáceas , Água
17.
Appl Microbiol Biotechnol ; 105(23): 8783-8793, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34741642

RESUMO

The established human health benefits of carotenoids along with the contemporary consumption of natural carotenoids bring the necessity to sustainable production of carotenoids. Among, marine diatoms have emerged as the potential biological resources for carotenoid production; however, their relatively lower yield in native strains provides the impetus to genetically improve the diatoms to cope with the burgeoning demand. In this study, we genetically improved the diatom Phaeodactylum tricornutum by overexpressing key carotenogenic genes involved in methylerythritol phosphate (MEP) pathway. The genes with lower relative transcript level under optimum conditions such as CMK and CMS were selected and overexpressed in P. tricornutum individually. Both CMK and CMS overexpressing lines exhibited elevated growth and photosynthesis. The expression of key carotenogenic genes such as PSY, PDS, ZDS, CRT, and LCYB was significantly upregulated. Furthermore, total carotenoid content was significantly increased; particularly, fucoxanthin content was increased by 1.83- and 1.82-fold in engineered lines CMK and CMS, respectively. Together, the results identify the potential metabolic targets and also uncover the crucial role of MEP pathway in redirecting metabolic precursors towards carotenogenesis. KEY POINTS: • Low abundant genes CMS and CMK of MEP pathway were overexpressed in the diatom • Total carotenoid content was increased, particularly fucoxanthin • Critical metabolic nodes were uncovered to accelerate fucoxanthin biosynthesis.


Assuntos
Diatomáceas , Carotenoides , Diatomáceas/genética , Humanos , Fosfatos , Xantofilas
18.
Zootaxa ; 5032(2): 225-236, 2021 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-34811132

RESUMO

Based on material originating from five amber collections of Eocene Baltic amber, Protostomopsis pandema gen. et sp. nov. is described and illustrated using X-ray micro-computed tomography. It is the first formally described extinct species of Cerylonidae, and the first known Palaearctic representative of the subfamily Ostomopsinae. As such, the new species extends the temporal range of the family Cerylonidae by approximately 45 Ma.


Assuntos
Besouros , Diatomáceas , Âmbar , Animais , Fósseis , Microtomografia por Raio-X
19.
Environ Monit Assess ; 193(12): 810, 2021 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-34783911

RESUMO

The present study deals with the broader understanding of phytoplankton assemblage pattern and their ecohydrological interactions in two ecologically distinct floodplain wetlands of Teesta - Torsa basin, India. Analyses of data revealed significant seasonal variations (p ≤ 0.05) of ten water variables (temperature, transparency, pH, conductivity, total dissolved solids, dissolved oxygen, total hardness, total alkalinity, PO4 - P, and SiO4 - Si) in both the wetlands; however, no significant variation was observed among the sampling stations. In total, 128 species of phytoplankton were recorded (118 species belonging to 94 genera in seasonally open; 103 species belonging to 86 genera in closed wetland). Four algal groups, viz. Cyanophyceae, Coscinodiscophyceae, Bacillariophyceae, and Chlorophyceae, were the dominant quantitative component, remarkably influencing the total phytoplankton population in both the wetlands, contributing ~ 87% of total phytoplankton. Species Aulacoseira granulata alone contributed 12 - 41% and 8 - 34% to the total phytoplankton in the seasonally open and closed wetland, respectively, and indicated high organic load in both the wetlands. Altogether thirty-six and thirty-one phytoplankton taxa appeared as major indicators across the seasons for seasonally open and closed wetland, respectively. The indicator taxa (Aulacoseira, Oscillatoria, Dolichospermum, Spirogyra, Synedra, Nitzschia, Navicula, Euglena, Phacus) in both the wetlands hinted that the wetlands are under pollution pressure. The assemblage structure of phytoplankton was related to transparency, NO3 - N, PO4 - P, SiO4 - Si, total dissolved solids, and temperature as evident from BIO - ENV. Furthermore, the marginal test also selected similar variables (depth, transparency, conductivity, PO4 - P, SiO4 - Si) for seasonally open and the variables such as depth, conductivity, total dissolved solids, total alkalinity, and NO3 - N for the closed wetland. The study showed that the seasonal riverine connectivity greatly influences the variations in phytoplankton community in the seasonally open wetland.


Assuntos
Diatomáceas , Fitoplâncton , Monitoramento Ambiental , Índia , Estações do Ano , Áreas Alagadas
20.
BMC Genomics ; 22(1): 746, 2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-34654361

RESUMO

BACKGROUND: Skeletonema species are prominent primary producers, some of which can also cause massive harmful algal blooms (HABs) in coastal waters under specific environmental conditions. Nevertheless, genomic information of Skeletonema species is currently limited, hindering advanced research on their role as primary producers and as HAB species. Mitochondrial genome (mtDNA) has been extensively used as "super barcode" in the phylogenetic analyses and comparative genomic analyses. However, of the 21 accepted Skeletonema species, full-length mtDNAs are currently available only for a single species, S. marinoi. RESULTS: In this study, we constructed full-length mtDNAs for six strains of five Skeletonema species, including S. marinoi, S. tropicum, S. grevillei, S. pseudocostatum and S. costatum (with two strains), which were isolated from coastal waters in China. The mtDNAs of all of these Skeletonema species were compact with short intergenic regions, no introns, and no repeat regions. Comparative analyses of these Skeletonema mtDNAs revealed high conservation, with a few discrete regions of high variations, some of which could be used as molecular markers for distinguishing Skeletonema species and for tracking the biogeographic distribution of these species with high resolution and specificity. We estimated divergence times among these Skeletonema species using 34 mtDNAs genes with fossil data as calibration point in PAML, which revealed that the Skeletonema species formed the independent clade diverging from Thalassiosira species approximately 48.30 Mya. CONCLUSIONS: The availability of mtDNAs of five Skeletonema species provided valuable reference sequences for further evolutionary studies including speciation time estimation and comparative genomic analysis among diatom species. Divergent regions could be used as molecular markers for tracking different Skeletonema species in the fields of coastal regions.


Assuntos
Diatomáceas , Genoma Mitocondrial , DNA Mitocondrial , Diatomáceas/genética , Proliferação Nociva de Algas , Filogenia
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