scholarly journals Effects of Algal Utilization of Dissolved Organic Phosphorus by Microcystis Aeruginosa on its Adaptation Capability to Ambient Ultraviolet Radiation

Author(s):  
Lingxiao Ren ◽  
Jing Huang ◽  
Junpan Zhu ◽  
Ning Qi ◽  
Keqiang Ding ◽  
...  

Abstract Phosphorus (P) plays an important role in eutrophication and algal adaptation to environmental stresses; therefore, a better understanding of the impact of P is essential to control cyanobacterial bloom. In this study, Microcystis aeruginosa was treated with 5-h of ambient irradiation in the culture medium with different availability of dissolved organic P (DOP) and dissolved organic matter (DOM), to explore algal responses. Compared to photosynthetically active radiation (PAR), ambient UV-A and UV-B radiation exerted oxidative stresses and had inhibitive effects on the growth and photosynthesis of M. aeruginosa in DOP-rich medium. However, M. aeruginosa had a strong adaptation capability and the negative effects of UV radiation were eliminated with DOM addition (5 mg L− 1 humic acid [HA]). Combining dissolved inorganic P (DIP) and DOP contents in the culture medium, adaptation of M. aeruginosa to UV radiation in the DOP-rich waters could be mainly achieved through the hydrolysis of DOP and metabolism of DIP, and the DOP utilization behaviors of M. aeruginosa greatly affected its UV adaptation capability. In DOP-rich medium without DOM, APase inactivation after UV radiation negatively affected DOP utilization by M. aeruginosa, and algal P demand for UV adaptation could not be fully met. DOM could act as an antioxidant and greatly decreased APase inactivation after UV radiation, when M. aeruginosa utilized DOP faster to produce more DIP and to increase algal carotenoid, phycocyanin production and its superoxide dismutase (SOD) activity in the DOP-rich medium, resulting in a strong UV adaptation capability. Consequently, M. aeruginosa showed the lowest adaptation capability to UV radiation in the DOP-free medium. Overall, our findings indicated the close relationship of algal DOP utilization and its adaptation to ambient UV radiation of typical cyanobacteria in DIP-limited and DOP-enriched natural waters.

2011 ◽  
Vol 356-360 ◽  
pp. 119-126
Author(s):  
Li Juan Huang ◽  
Xue Xiu Chang ◽  
Cheng Wu

The laboratory experiment was conducted to investigated the effect of nickel over a concentration gradient of 0.1~1.00 mg/L on biomass ( indicated by absorbance of cell culture at 663nm wavelength ), superoxide anion (O2•ˉ), malondialdehyde (MDA), and superoxide dismutase (SOD) in the cyanobacterium Microcystis aeruginosa FACHB 905 isolated from Dianchi Lake, south west of China . The results showed: (1) M. aeruginosa could live normally in Ni (II)-absence culture medium,but 0.3 mg/L Ni(II) was the fittest concentration for test M. aeruginosa, in which biomass and SOD activity were highest among all test cultures; (2) Ni(II) induced O2•ˉ and MDA in M. aeruginosa cells under the experimental condition, showing that Ni(II) could influence on M. aeruginosa by inducing oxidative stress; (3) Fe-SOD and Mn-SOD were found in M. aeruginosa and both of them were induced by lower Ni(II) but inhibited by higher concentration. The multiformity of SOD isoenzymes enhance the resistance of M. aeruginosa to oxygen stress induced by unfavorable condition, which explained that M. aeruginosa is the preponderant species in badly polluted Dianchi Lake water for long period.


Animals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1414
Author(s):  
Josep M. Cambra ◽  
Emilio A. Martinez ◽  
Heriberto Rodriguez-Martinez ◽  
Maria A. Gil ◽  
Cristina Cuello

The development of chemically defined media is a growing trend in in vitro embryo production (IVP). Recently, traditional undefined culture medium with bovine serum albumin (BSA) has been successfully replaced by a chemically defined medium using substances with embryotrophic properties such as platelet factor 4 (PF4). Although the use of this medium sustains IVP, the impact of defined media on the embryonic transcriptome has not been fully elucidated. This study analyzed the transcriptome of porcine IVP blastocysts, cultured in defined (PF4 group) and undefined media (BSA group) by microarrays. In vivo-derived blastocysts (IVV group) were used as a standard of maximum embryo quality. The results showed no differentially expressed genes (DEG) between the PF4 and BSA groups. However, a total of 2780 and 2577 DEGs were detected when comparing the PF4 or the BSA group with the IVV group, respectively. Most of these genes were common in both in vitro groups (2132) and present in some enriched pathways, such as cell cycle, lysosome and/or metabolic pathways. These results show that IVP conditions strongly affect embryo transcriptome and that the defined culture medium with PF4 is a guaranteed replacement for traditional culture with BSA.


Atmosphere ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 125 ◽  
Author(s):  
Brian Diffey

In the early 1970s, environmental conservationists were becoming concerned that a reduction in the thickness of the atmospheric ozone layer would lead to increased levels of ultraviolet (UV) radiation at ground level, resulting in higher population exposure to UV and subsequent harm, especially a rise in skin cancer. At the time, no measurements had been reported on the normal levels of solar UV radiation which populations received in their usual environment, so this lack of data, coupled with increasing concerns about the impact to human health, led to the development of simple devices that monitored personal UV exposure. The first and most widely used UV dosimeter was the polymer film, polysulphone, and this review describes its properties and some of the pioneering studies using the dosimeter that led to a quantitative understanding of human exposure to sunlight in a variety of behavioral, occupational, and geographical settings.


2016 ◽  
Vol 20 (1) ◽  
pp. 13-22
Author(s):  
Beata Brzychczyk ◽  
Zbigniew Kowalczyk ◽  
Jan Giełżecki

AbstractThe objective of the paper was to analyse the use of the designed photobioreactor for freshwater microalgae cultivation in the controlled laboratory conditions. The work covered the design and construction of photobioreactors (PBR) and setting up comparative cultivations of freshwater microalgae chlorelli vulgaris along with determination of the biomass growth intensity for a varied amount of supplied culture medium. It was found out that the constructed PBR may be used for microalgae cultivation in the controlled conditions. The impact of the culture medium amount on the growth of chlorelli vulgaris was proved. As a result of the increase of culture medium concentration to 30.1-120.4 ml·l−1 of water, dry mass in photobioreactorsincreased respectively from 1.33 g·dm−3 to 4.68 g·dm−3.


2017 ◽  
Vol 65 (2) ◽  
pp. 250-254 ◽  
Author(s):  
Barbara Kammerlander ◽  
Barbara Tartarotti ◽  
Bettina Sonntag
Keyword(s):  

2007 ◽  
Vol 73 (21) ◽  
pp. 6994-7002 ◽  
Author(s):  
Sabine J�hnichen ◽  
Tilo Ihle ◽  
Thomas Petzoldt ◽  
J�rgen Benndorf

ABSTRACT Batch culture experiments with the cyanobacterium Microcystis aeruginosa PCC 7806 were performed in order to test the hypothesis that microcystins (MCYSTs) are produced in response to a relative deficiency of intracellular inorganic carbon (Ci,i). In the first experiment, MCYST production was studied under increased Ci,i deficiency conditions, achieved by restricting sodium-dependent bicarbonate uptake through replacement of sodium bicarbonate in the medium with its potassium analog. The same experimental approach was used in a second experiment to compare the response of the wild-type strain M. aeruginosa PCC 7806 with its mcyB mutant, which lacks the ability to produce MCYSTs. In a third experiment, the impact of varying the Ci,i status on MCYST production was examined without suppressing the sodium-dependent bicarbonate transporter; instead, a detailed investigation of a dark-light cycle was performed. In all experiments, a relative Ci,i deficiency was indicated by an elevated variable fluorescence signal and led to enhanced phycocyanin cell quotas. Higher MCYST cell quotas (in the first and third experiments) and increased total (intracellular plus extracellular) MCYST production (in the first experiment) were detected with increased Ci,i deficiency. Furthermore, the MCYST-producing wild-type strain and its mcyB mutant showed basically the same response to restrained inorganic carbon uptake, with elevated variable fluorescence and phycocyanin cell quotas with increased Ci,i deficiency. The response of the wild type, however, was distinctly stronger and also included elevated chlorophyll a cell quotas. These differences indicate the limited ability of the mutant to adapt to low-Ci,i conditions. We concluded that MCYSTs may be involved in enhancing the efficiency of the adaptation of the photosynthetic apparatus to fluctuating inorganic carbon conditions in cyanobacterial cells.


2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
B Aparicio Ruiz ◽  
L Bori ◽  
E Paya ◽  
M A Valera ◽  
A Quiñonero ◽  
...  

Abstract Study question Would it be possible to predict embryo ploidy by taking into account conventional morphological and morphokinetic parameters together with IL-6 concentration in spent culture medium? Summary answer Our artificial neural network (ANN) trained with blastocyst morphology, embryo morphokinetics and IL-6 concentration distinguished between euploid/aneuploid embryos in 65% of the testing dataset. What is known already The analysis of spent embryo culture media represents the protein and metabolic state of the embryo and could be a non-invasive method of obtaining information about embryo quality. The impact of the presence/absence of several proteins in embryo culture samples over clinical results has been widely studied. The IL-6 is one of the most mentioned protein for its effect on embryo development, implantation and likelihood of achieving a live birth. In this initial attempt, we examined the predictive value for euploidy of a model that took into account the concentration of IL-6 in the spent culture medium. Study design, size, duration This prospective study included 319 embryos with PGT-A results. Out of the total, 127 were euploid and 192 aneuploid embryos. Concentration of IL-6 in spent embryo culture media (collected on the day of trophectoderm biopsy-fifth/sixth day of development), morphokinetic parameters (division time to 2 cells-t2; to 3 cells-t3, to 4 cells-t4; to 5 cells-t5 and time of blastocyst formation-tB) and blastocyst morphological grade (according to ASEBIR criteria) were considered to predict the embryo ploidy. Participants/materials, setting, methods Embryos were cultured in EmbryoScope. The chromosome analysis was performed using next-generation sequence technology. The concentration of IL-6 was measured in 20µL of spent embryo culture media with ELISA kits. Morphokinetic parameters were automatically annotated and the blastocyst morphology was evaluated by senior embryologists based on blastocele expansion, inner cell mass and trophectoderm quality. All the embryos were divided into 70% for training, 15% for validating and 15% for testing our ANN model with MatLab®. Main results and the role of chance The general description for the euploid embryo population was the following: 2% of the embryos were graded as A, 71% were graded as B and 28% were graded as C; the means and standard deviations were 25.32±2.97 hours (h) for t2, 35.33±5.15h for t3, 37.30±5.43h for t4, 48.24±6.62h for t5 and 103.93±12.8h for tB; and the average of IL-6 concentration was 1.51±0.70 pg/ml. The general description for the aneuploid embryo population was the following: 1% of the embryos were graded as A, 48% were graded as B and 51% were graded as C; the means and standard deviations were 26.13±3.51h for t2, 36.70±4.29h for t3, 38.20±4.24h for t4, 49.86±6.89h for t5 and 107.10±8.29h for tB; and the average of IL-6 concentration was 1.47±0.71 pg/ml. Our ANN model showed a higher general success rate as we increased the variables considered in the final prediction of euploid embryos. The accuracy, sensitivity and specificity for the testing dataset were: 0.60, 0.12 and 0.87 with morphokinetic parameters; 0.63, 0.24 and 0.93 with morphokinetics and IL-6 concentration; and 0.65, 0.16 and 0.96 with morphokinetics, IL-6 concentration and blastocyst morphological grade. Limitations, reasons for caution The low sensitivity and high specificity achieved in our models indicated that they were more capable of detecting aneuploid than euploid embryos. As this was a preliminary study, the small number of embryos included in the test (n = 48) was also a limitation. Wider implications of the findings The results showed that our model tended to classify the embryos as aneuploid. More euploid embryos would be necessary to train our model and achieve better results in the prediction of chromosomally normal embryos. Further studies with large number of embryos and additional variables could improve the non-invasive ploidy prediction. Trial registration number not applicable


2013 ◽  
Vol 10 (12) ◽  
pp. 8139-8157 ◽  
Author(s):  
M. W. Matthews ◽  
S. Bernard

Abstract. A two-layered sphere model is used to investigate the impact of gas vacuoles on the inherent optical properties (IOPs) of the cyanophyte Microcystis aeruginosa. Enclosing a vacuole-like particle within a chromatoplasm shell layer significantly altered spectral scattering and increased backscattering. The two-layered sphere model reproduced features in the spectral attenuation and volume scattering function (VSF) that have previously been attributed to gas vacuoles. This suggests the model is good at least as a first approximation for investigating how gas vacuoles alter the IOPs. Measured Rrs was used to provide a range of values for the central value of the real refractive index, 1 + ε, for the shell layer using measured IOPs and a radiative transfer model. Sufficient optical closure was obtained for 1 + ε between 1.1 and 1.14, which had corresponding Chl a-specific phytoplankton backscattering, bbφ*, between 3.9 and 7.2 × 10−3 m2 mg−1 at 510 nm. The bbφ* values are in close agreement with the literature and in situ particulate backscattering measurements. Rrs simulated for a population of vacuolate cells was greatly enlarged relative to a homogeneous population. A sensitivity analysis of empirical algorithms for estimating Chl a in eutrophic/hypertrophic waters suggests these are robust under variable constituent concentrations and likely to be species-sensitive. The study confirms that gas vacuoles cause significant increase in backscattering and are responsible for the high Rrs values observed in buoyant cyanobacterial blooms. Gas vacuoles are therefore one of the most important bio-optical substructures influencing the IOPs in phytoplankton.


Pharmaceutics ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 102
Author(s):  
Natalia Zaręba ◽  
Klaudia Więcławik ◽  
Rene Kizek ◽  
Bozena Hosnedlova ◽  
Marta Kepinska

This study aimed to synthesise C60–DOX complexes followed by the analysis of their effect on the concentration of metallothionein (MT) as a non-enzymatic antioxidant and on the concentration and activity of superoxide dismutase (SOD) as an antioxidant enzyme in healthy human mammary MCF-10A cells. Dynamic light scattering and electrophoretic light scattering were used to establish the size and zeta potential of the complexes. The MT and SOD concentrations were determined using the ELISA method; SOD activity was determined by tetrazolium salt reduction inhibition. Lower MT concentration following exposure of cells to both DOX and C60 fullerene compared to the control sample was found. However, the concentration of this protein increased as a consequence of the C60–DOX complexes action on MCF-10A cells compared to the control. C60 used alone did not affect the concentration and activity of SOD in MCF-10A cells. Application of free DOX did not activate cellular antioxidant defence in the form of an increase in SOD concentration or its activity. In contrast treatment of cells with the C60–DOX complex resulted in a decrease in SOD1 concentration and a significant increase in SOD activity compared to cells treated with free DOX, C60 and control. Thus, it was found that C60–DOX complexes showed potential for protective effects against DOX-induced toxicity to MCF-10A cells.


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