Performance of co-culture strategy on nutrient removal and biogas upgrading by strigolactone induction.

In this study, we investigated the performance and elucidated the synergistic effects of microalgae-fungi symbionts co-cultured with 10-7 and 10-9  mol L-1 of GR24 and supplemented with endophytic bacteria, multi-walled carbon nanotubes (MWCNTs) or vitamin B12 (VB12), on nutrient removal and biogas upgrading. The results showed that the microalgae-fungi-bacteria symbiotic system co-cultured with 10-9  mol L-1 GR24 presented the optimal growth performance of 0.368 ± 0.04 d-1 , chlorophyll a of 249.36 ± 22.31 µg L-1 , and extracellular carbonic anhydrase activity of 42.55 ± 3.755 enzyme units. In this co-culture system, the organic matter, nutrients, and CO2 purification obtained the highest removal efficiency, with 81.35 ± 7.96% for chemical oxygen demand, 83.56 ± 7.91% total nitrogen, 84.17 ± 7.95% total phosphorus, and 63.72 ± 6.06% CO2 . The symbiont system also greatly increased the methane content in the biogas by 30.67%. The remarkable performance of the microalgae-fungi-bacteria symbiotic system shows its ability to be broadly applied in simultaneous biogas upgrading and wastewater treatment. PRACTITIONER POINTS: The optimal GR24 concentration for microalgae-fungi consortia was 10-9  M. Endophytic bacteria were superior to MWCNTs and VB12. Fungi-algae-bacteria consortia presented excellent growth and removal performance. Removal efficiencies of COD, TN, and TP were about 81% under optimum treatment.

Supplementation of 5-deoxystrigol for higher pollutant removal and biogas quality improvement by different microalgae-based technologies.

The treatment of biogas slurry by microalgae technology has the characteristics of low cost, environmental protection, and high efficiency. In this paper, the effects of four microalgae technologies, namely, monoculture of Scenedesmus obliquus (S. obliquus), co-culture of S. obliquus-activated sludge, co-culture of S. obliquus-Ganoderma lucidum (G. lucidum), and co-culture of S. obliquus-G. lucidum-activated sludge, on the treatment of biogas slurry were investigated. In addition, the effects of 5-deoxystrigol (5-DS) concentration and mixed light wavelengths (red-blue light intensity ratio) on nutrient removal and biogas upgrading were also investigated. The results showed that 5-DS significantly promoted the growth and photosynthetic performance of the microalgal system. The best purification performance could be achieved by co-cultivation of S. obliquus-G. lucidum-activated sludge when the 5-DS concentration was 10-11  M, and the red-blue light intensity ratio was 5:5 (225:225 µmol m-2  s-1 ). The maximum average removal efficiencies for chemical oxygen demand (COD), total nitrogen (TN), total phosphorus (TP), and carbon dioxide (CO2 ) were 83.25 ± 7.87%, 83.62 ± 7.78%, 84.19 ± 8.25%, and 71.68 ± 6.73%, respectively. The co-culture technology of S. obliquus-G. lucidum-activated sludge had great potential and superiority in removing nutrients from biogas slurry and upgrading biogas at the same time. The results of this study will provide a reference for the simultaneous purification of wastewater and upgrading of biogas using microalgae technology. PRACTITIONER POINTS: S. obliquus-G. lucidum-activated sludge consortium showed the best removal performance. 10-11 M 5-DS greatly promoted the purification performance. Removal efficiencies of COD, TN, and TP were more than 83%.

The response mechanism of Hydrilla verticillata and leaf epiphytic biofilms to depth and nutrient removal.

The mechanism of morphological and physiological regulation of submerged aquatic plants (Hydrilla verticillata) is influenced by spatial and environmental changes related to water depth gradients. In the present study, changes in the aquatic microcosm were explored at the depth gradients of 0.3 m, 0.6 m, 0.9 m, 1.2 m, and 1.5 m, and the depth was recognized as a critical factor for improving water quality, especially for the removal of total phosphorus (TP) and recalcitrant protein-like molecules. At 0.9 m, the removal rates of TP and protein-like substances reached 78% and 18.67%, respectively, 1.76 times and 1.28 times the rates at 0.3 m. The maximum shoot/root growth and chlorophyll (a + b) suggest photosynthesis inhibition is minimal at 1.2 m. Fluctuations in enzyme activities imply an antioxidant response to lipid peroxidation damage under different oxidative stress. The adjusted activities of glutamine synthetase (GS) and alkaline phosphatase (APA) were an adaptive nutrient utilization strategy to different water depths. Microbiological diversity analysis of biofilms indicates that community structure changes in response to water depth. Considering the growth status and nutrient removal effects, the results indicate that the optimal planting depth for H. verticillata is 0.9-1.2 m. These findings contribute to understanding water purification mechanisms in depth gradients, and support the effective rebuilding and management of submerged macrophyte communities in natural shallow lakes.

Effect and mechanism of prophylactic use of tadalafil during pregnancy on l-NAME-induced preeclampsia-like rats.

INTRODUCTION: Preeclampsia (PE) is a serious maternal inflammatory disease with endothelial cell dysfunction, and there is a lack of effective treatment and prevention. Tadalafil is considered to be a promising drug for PE. This study aimed to determine whether and how tadalafil use during early pregnancy alleviates PE induced by N-nitro-l-arginine-methyl-ester (l-NAME), an antagonist of nitric oxide synthase, in rats. METHODS: Twenty-eight Sprague-Dawley (SD) rats were randomly divided into 4 equal groups on gestational day 0 (GD0): a pregnant control group, an l-NAME-treated PE group and two prophylactic low-dose and high-dose tadalafil groups. Blood pressure was measured on GD0, 5, 10, 15 and 20. Proteinuria was assessed on GD0 and 18. Femoral artery ultrasound was performed on GD19. Tissue sampling was performed on GD20. The perinatal outcomes, placenta and kidney tissue morphology, and endothelial and inflammatory markers were examined. RESULTS: Prophylactic administration of low and high doses of tadalafil improved l-NAME induced hypertension, proteinuria, maternal weight loss during pregnancy, fetal growth restriction and flow-mediated dilatation, balanced endothelial-relative factors, and alleviated inflammation activation in placenta and kidney tissue. What's more, in some results, the HT group performed better than the LT group. DISCUSSION: Our results indicate that prophylactic use of tadalafil in l-NAME-induced PE-like rat models alleviates PE symptoms, promotes fetal growth, protects endothelial function and reduces inflammation, suggesting that tadalafil may be a potential drug for the prevention of PE.

Dose Effects of Orally Administered Spirulina Suspension on Colonic Microbiota in Healthy Mice.

Oral supplemented nutraceuticals derived from food sources are surmised to improve the human health through interaction with the gastrointestinal bacteria. However, the lack of fundamental quality control and authoritative consensus (e.g., formulation, route of administration, dose, and dosage regimen) of these non-medical yet bioactive compounds are one of the main practical issues resulting in inconsistent individual responsiveness and confounded clinical outcomes of consuming nutraceuticals. Herein, we studied the dose effects of widely used food supplement, microalgae spirulina (Arthrospira platensis), on the colonic microbiota and physiological responses in healthy male Balb/c mice. Based on the analysis of 16s rDNA sequencing, compared to the saline-treated group, oral administration of spirulina once daily for 24 consecutive days altered the diversity, structure, and composition of colonic microbial community at the genus level. More importantly, the abundance of microbial taxa was markedly differentiated at the low (1.5 g/kg) and high (3.0 g/kg) dose of spirulina, among which the relative abundance of Clostridium XIVa, Desulfovibrio, Eubacterium, Barnesiella, Bacteroides, and Flavonifractor were modulated at various degrees. Evaluation of serum biomarkers in mice at the end of spirulina intervention showed reduced the oxidative stress and the blood lipid levels and increased the level of appetite controlling hormone leptin in a dose-response manner, which exhibited the significant correlation with differentially abundant microbiota taxa in the cecum. These findings provide direct evidences of dose-related modulation of gut microbiota and physiological states by spirulina, engendering its future mechanistic investigation of spirulina as potential sources of prebiotics for beneficial health effects via the interaction with gut microbiota.