Alleviating CTAC and Flu combined pollution damage in Chlorella vulgaris by exogenous nitric oxide

New insights into the effect of NdhO levels on cyanobacterial cell death triggered by high temperature

NdhO, a regulatory oxygenic photosynthesis-specific subunit, is close to the ferredoxin-binding site of cyanobacterial NDH-1, and its levels are negatively associated with the rates of cyclic electron transfer around PSI mediated by NDH-1 (NDH-CET). However, the effect of NdhO levels on cyanobacterial cell death triggered by high temperature remains elusive. Here, our results uncovered a synergistic effect of NdhO levels on the cell death and reactive oxygen species (ROS) accumulation when cyanobacterial cells grown at 30°C for 1 day were transferred to 45°C for 2 days. Such synergistic effect was found to be closely associated with the activities of NDH-CET and CO2 assimilation during high temperature. Collectively, we propose that the effect of NdhO levels on the cyanobacterial cell bleaching and cell death triggered by high temperature is a result of influencing production of ROS by NDH-CET, which is considered to be vital to balance the ATP/NADPH ratio and improve the Calvin-Benson cycle.

Nitric oxide production and signalling in algae

Nitric oxide (NO) was the first identified gaseous messenger and is now well established as a major ubiquitous signalling molecule. The rapid development of our understanding of NO biology in embryophytes came with the partial characterization of the pathways underlying its production and with the decrypting of signalling networks mediating its effects. Notably, the identification of proteins regulated by NO through nitrosation greatly enhanced our perception of NO functions. In comparison, the role of NO in algae has been less investigated. Yet, studies in Chlamydomonas reinhardtii have produced key insights into NO production through the identification of NO-forming nitrite reductase and of S-nitrosated proteins. More intriguingly, in contrast to embryophytes, a few algal species possess a conserved nitric oxide synthase, the main enzyme catalysing NO synthesis in metazoans. This latter finding paves the way for a deeper characterization of novel members of the NO synthase family. Nevertheless, the typical NO-cyclic GMP signalling module transducing NO effects in metazoans is not conserved in algae, nor in embryophytes, highlighting a divergent acquisition of NO signalling between the green and the animal lineages.

Impact of Cultivation Condition and Media Content onChlorella vulgaris Composition

Microalgae are a source material in food, pharmacy, and cosmetics industries for producing various products including high-protein nutritional supplements, synthetic pharmaceuticals, and natural colors. A promising algal source for such productions is Chlorella vulgaris which contains a considerable protein content. Similar to other microalgae, its desirability is minimal nutrient requirements since they are unicellular, photosynthetic, and fast-growing microorganisms. Another propitious option to be produced by C. vulgaris is biodiesel, since it is rich in oil too. Besides, algal well thriving in presence of increased amount of carbon dioxide makes them a practicable alternative biofuel resource without some problems of the traditional ones. At the same time, C. vulgaris is also a promising source for nutraceuticals such as amino acids, vitamins, and antioxidants. This review aims to discuss the conditions need to be observed for achieving a favorable growth efficiency of the C. vulgaris, as well as targeted productions such as biomass, antioxidant, and biofuel. Additionally, different approaches to induce any specific production are also considered comprehensively.

Effects of amendments on heavy metal immobilization and uptake by Rhizoma chuanxiong on copper and cadmium contaminated soil

An improved method was applied for remediating cadmium and copper co-contaminated soil and reducing the metal concentration in Rhizoma chuanxiong. Pot experiments were conducted with six amendments (composed with bentonite, phosphate, humic acid, biochar, sepiolite powder, etc.). The results showed that soil pH, biological activities (soil enzymatic activities and microbial counts) and R. chuanxiong biomass were greatly improved with the addition of amendments in all treatments, especially in T3 and T6. Also, amendments effectively decreased the concentration of malondialdehyde and H₂O₂ in R. chuanxiong. In the T3 treatment, the bio-available Cd and Cu in soil were significantly decreased by 0.53 and 0.41 mg kg^-1, respectively. Meanwhile, the amendment in T3 reduced Cd and Cu accumulation in R. chuanxiong about 45.83 and 39.37%, respectively, compared to T0. Moreover, the Fourier transform infrared spectroscopy spectra showed the surface functional groups of every amendment. To conclude, this study offers an effective and environmental method to reduce metal accumulation in R. chuanxiong on heavy metal co-contaminated soil.

Alleviating the toxicity of heavy metals by combined amendments in cultivated bag of Pleurotus cornucopiae

The substrate of mushroom can be polluted with heavy metals and subsequently contaminate mushroom, which requires alternative solutions to reduce associated environmental and human health risks. The effects of amendment application on alleviating Cu and Cd toxicities to Pleurotus cornucopiae were investigated in a cultivated bag experiment conducted with the naturally contaminated substrate. Addition of combined amendments (sodium bentonite, silicon fertilizer, activated carbon, and potassium dihydrogen phosphate) increased the P. cornucopiae biomass and substrate pH. Cu and Cd concentration in P. cornucopiae as well as the available Cu and Cd in substrate reduced for the presence of amendments, and the silicon fertilizer had the biggest inhibition on metal uptake. The smallest amount of Cu and Cd in P. cornucopiae was only 30.8 and 5.51% of control, respectively. Moreover, application of amendments also decreased malondialdehyde (MDA) and hydrogen peroxide (H2O2) level in metal-stressed mushroom by 4.38-53.74 and 8.90-58.42% relative to control, respectively. The decreased oxidative stress could well contribute to the growth of P. cornucopiae, and the elevated substrate pH might lead to the lower metal availability, thus resulting in the reduction of metal accumulation in mushroom. These above results suggest that application of combined amendments in mushroom substrate could be implemented in a general scheme aiming at controlling metal content in P. cornucopiae.

Nitric oxide enhances keratinocyte cell migration by regulating Rho GTPase via cGMP-PKG signalling

Objective

Nitric oxide (NO) has been shown to improve wound healing, but the mechanism underlying this function is not well defined. Here, we explored the effect of NO on the migration of a human keratinocyte cell line (HaCaT) and its possible mechanism.

Methods

The effects of NO on HaCaT cells in the presence of different concentrations of the NO donor sodium nitroprusside (SNP) were evaluated in a cell migration assay. Subsequently, the cytoskeleton reorganization of cultured HaCaT cells stained with rhodamine-phalloidin was observed with a confocal laser scanning microscope. The mRNA expression and active proteins of CDC42, Rac1 and RhoA in the cultured cells were determined via RT-PCR and pull-down assays, respectively. Furthermore, the roles of various inhibitors or agonists specific to cGMP, PKG and CDC42, Rac1, RhoA in the effects of NO on HaCaT cell migration, F-actin stress fibre formation, and Rho GTPase expression were observed.

Results

It was also found HaCaT cell migration was increased by SNP in a dose-dependent manner, and the other two NO donors either spermine NONOate or SNAP had almost the same effects on HaCat cell migrations. The formation of F-actin stress fibres in SNP-treated HaCaT cells was increased. The mRNA expression and the active proteins of CDC42, Rac1 and RhoA were found to be upregulated after SNP treatment. Similar effects were observed after the cells were treated with a cGMP or PKG agonist. Additionally, the SNP-mediated upregulation of the mRNA expression and the active proteins of CDC42, Rac1 and RhoA were inhibited by the addition of an inhibitor of cGMP or PKG. Moreover, the SNP-mediated promoting effects of migration and cytoskeleton reorganization were inhibited by treatment with inhibitors of cGMP, PKG, CDC42, Rac1 and RhoA respectively.

Conclusion

Our data indicated that the stimulatory effects of NO on cell migration of HaCaT cells are mediated by the cGMP signalling pathway via the upregulation of Rho-GTPase expression, which might promote cytoskeleton reorganization.