MlrA, an Essential Enzyme for Microcystins and Nodularin on First Step Biodegradation in Microcystin-Degrading Bacteria.

Microcystin-degrading bacteria first degrade microcystins by microcystinase A (MlrA) to cleave the cyclic structure of microcystins at the Adda-Arg site of microcystin-LR, microcystin-RR, and microcystin-YR, but the cleavage of the other microcystins was not clear. In our study, the microcystin-degrading bacterium Sphingopyxis sp. C-1 as wild type and that of mlrA-disrupting mutant, Sphingopyxis sp. CMS01 were used for microcystins biodegradation. The results showed MlrA degraded microcystin-LA, microcystin-LW, microcystin-LY, microcystin-LF, and nodularin. MlrA could cleave the Adda-L-amino acid site.

Exosomes in ascites from patients with human pancreatic cancer enhance remote metastasis partially through endothelial-mesenchymal transition.

BACKGROUND: Despite advances in multidisciplinary treatment, the prognosis of pancreatic cancer remains poor. Since distant metastasis defines prognosis, elucidation of the mechanism of metastasis is important for improving survival. Exosomes are extracellular secretory vesicles and are responsible for intercellular communication. In this study, we investigated whether exosomes secreted by human pancreatic cancer cells are involved in promoting distant metastasis of cancer and the mechanism that underlies the promotion of metastasis. METHODS: Exosomes were isolated from ascites of a patient with pancreatic cancer and a patient with liver cirrhosis as a control. Three days after the administration of exosomes to nude mice, GFP-labeled human pancreatic cancer cells were injected via the spleen or tail vein, and then the liver and lungs were histologically analyzed. To elucidate the mechanism, vascular permeability was estimated using FITC-dextran in place of pancreatic cancer cells in vivo and human umbilical vascular endothelial cells (HUVECs) were used to analyze vascular permeability and the induction of endothelial-mesenchymal transition (EndMT) in vitro. RESULTS: Distant metastasis and vascular permeability were significantly enhanced in mice treated with exosomes from pancreatic cancer patients in comparison to exosomes from a control patient in vivo. In addition, exosomes from pancreatic cancer patients significantly enhanced vascular permeability and the induction of EndMT in HUVECs in vitro. CONCLUSION: Exosomes derived from pancreatic cancer cells form a pre-metastatic niche and promote the extravasation and colonization of pancreatic cancer cells to remote organs, partially through endothelial-mesenchymal transition.

Toxicity of ciprofloxacin and ofloxacin to Moina macrocopa and investigation of p-value adjustments for (eco)toxicological studies.

Ciprofloxacin (CFX) and ofloxacin (OFX) are commonly found as residual contaminants in aquatic environments, posing potential risks to various species. To ensure the safety of aquatic wildlife, it is essential to determine the toxicity of these antibiotics and establish appropriate concentration limits. Additionally, in (eco)toxicological studies, addressing the issue of multiple hypothesis testing through p-value adjustments is crucial for robust decision-making. In this study, we assessed the no observed adverse effect concentration (NOAEC) of CFX and OFX on Moina macrocopa across a concentration range of 0-400 µg L-1. Furthermore, we investigated multiple p-value adjustments to determine the NOAECs. Our analysis yielded consistent results across seven different p-value adjustments, indicating NOAECs of 100 µg CFX L-1 for age at first reproduction and 200 µg CFX L-1 for fertility. For OFX treatment, a NOAEC of 400 µg L-1 was observed for both biomarkers. However, further investigation is required to establish the NOAEC of OFX at higher concentrations with greater certainty. Our findings demonstrate that CFX exhibits higher toxicity compared to OFX, consistent with previous research. Moreover, this study highlights the differential performance of p-value adjustment methods in terms of maintaining statistical power while controlling the multiplicity problem, and their practical applicability. The study emphasizes the low NOAECs for these antibiotics in the zooplanktonic group, highlighting their significant risks to ecological and environmental safety. Additionally, our investigation of p-value adjustment approaches contributes to a deeper understanding of their performance characteristics, enabling (eco)toxicologists to select appropriate methods based on their specific needs and priorities.

Algal-bacterial aerobic granular sludge for real municipal wastewater treatment: Performance, microbial community change and feasibility of lipid recovery.

Despite various research works on algal-bacterial aerobic granular sludge for wastewater treatment and resource recovery processes, limited information is available on its application in real wastewater treatment in terms of performance, microbial community variation and resource recovery. This study investigated the performance of algal-bacterial aerobic granular sludge on real low-strength wastewater treatment in addition to the characterization of microbial community and fatty acid compositions for biodiesel production. The results demonstrated 71% COD, 77% NH4+-N and 31% phosphate removal efficiencies, respectively. In addition, all the water parameters successfully met the effluent standard A, imposed by the Department of Environment (DOE) Malaysia. Core microbiome analyses revealed important microbial groups (i.e., Haliangium ochraceum, Burkholderiales and Chitinophagaceae) in bacterial community. Meanwhile the photosynthetic microorganisms, such as Oxyphotobacteria and Trebouxiophyceae dominated the algal-bacterial aerobic granular sludge, suggesting their important roles in granulation and wastewater treatment. Up to 12.51 mg/gSS lipid content was recovered from the granules. In addition, fatty acids composition showed high percetages of C16:0 and C18:0, demonstrating high feasibility to be used for biodiesel production application indicated by the cetane number, iodine value and oxidation stability properties.

Discovering future research trends of aerobic granular sludge using bibliometric approach.

The advantageous characteristics of aerobic granular sludge (AGS) have led to their increasing popularities among academics and industrial players. However, there has been no bibliometric report on current and future research trends of AGS. This study utilized the available reports of AGS in the Scopus database for comprehensive bibliometric analyses using VOSviewer software. A total of 1203 research articles from 1997 to 2020 were analyzed. The dominance of the Netherlands and China were revealed by the high number of publications and citations. Nevertheless, the Netherlands exhibited higher average citation per article at 76.4. A recent process of AGS involving biochar and algal addition were also identified. Meanwhile, the application of AGS for antibiotic containing wastewater as well as possibility of resource recovery were recently reported and was expected to expand in the future. It was suggested that application of AGS would develop further along with the development of sustainable wastewater treatment process.

Pancreatic cancer cell-derived exosomes induce epithelial-mesenchymal transition in human pancreatic cancer cells themselves partially via transforming growth factor ß1.

Distant metastasis is a dismal prognostic factor of pancreatic cancer. Metastasis is established in several steps, but the mechanism underlying the very early stages remains unclear. Epithelial-mesenchymal transition (EMT) is involved in these stages. Although signaling molecules have been reported to induce EMT, the mechanism underlying their origin is unclear. In this study, we hypothesized that pancreatic cancer cell-derived exosomes induce EMT in cancer cells themselves, a notion we entertained because we found EMT in in vitro three-dimensional colonies of cancer cells, with vimentin-positive cells observed in some of the budding pancreatic cancer cells and in single cells outside the colony as well. First, we clarified that pancreatic cancer cell-derived exosomes induce EMT in cancer cells themselves. Next, we examined the involvement of transforming growth factor-ß1 (TGF-ß1), and TGF-ß1 knock-down in pancreatic cancer cells with TGF-ß1 siRNA significantly suppressed TGF-ß1 gene expression in cancer cells, and exosomal TGF-ß1 was significantly reduced in the secretory exosomes. Exosomes from TGF-ß1 knock-down cells suppressed EMT induction in cancer cells themselves and TGF-ß1 protein expression in target cells. Taken together, these findings suggest that TGF-ß1 is involved in EMT induction via exosomes, results that may support the production of effective metastasis inhibitors.

Dynamics of the prokaryotic and eukaryotic microbial community during a cyanobacterial bloom.

Toxic cyanobacterial blooms frequently develop in eutrophic freshwater bodies worldwide. Microcystis species produce microcystins (MCs) as a cyanotoxin. Certain bacteria that harbor the mlr gene cluster, especially mlrA, are capable of degrading MCs. However, MC-degrading bacteria may possess or lack mlr genes (mlr+ and mlr- genotypes, respectively). In this study, we investigated the genotype that predominantly contributes to biodegradation and cyanobacterial predator community structure with change in total MC concentration in an aquatic environment. The 2 genotypes coexisted but mlr+ predominated, as indicated by the negative correlation between mlrA gene copy abundance and total MC concentration. At the highest MC concentrations, predation pressure by Phyllopoda, Copepoda, and Monogononta (rotifers) was reduced; thus, MCs may be toxic to cyanobacterial predators. The results suggest that cooperation between MC-degrading bacteria and predators may reduce Microcystis abundance and MC concentration.

Efficient capture of phosphate from aqueous solution using acid activated akadama clay and mechanisms analysis.

In this study, akadama clay, a kind of volcano ash, was activated with sulfuric acid and then evaluated for the adsorption of phosphate from aqueous solution via batch experiments. The effects of adsorbent dose, initial pH and coexisting anions on phosphate removal by natural akadama clay and acid-activated akadama clay were investigated. Based on the pH effect, the modified adsorbent could efficiently capture phosphate over a wider pH range of 3.00-6.00 than natural akadama clay. Competitive anions showed negative effects on the phosphate adsorption, especially citrate and carbonate. The adsorption process followed the pseudo-second-order kinetic equation and the intra-particle diffusion. Langmuir isotherm model was found to fit the data better than Freundlich model, and the maximum adsorption capacities of phosphate onto the natural akadama clay and acid-activated akadama clay were 5.88 and 9.19 mg/g, respectively. Furthermore, thermodynamic studies confirmed that the adsorption of acid-activated akadama clay was a spontaneous process. The mechanisms of phosphate adsorption on the clay could be ascribed to electrostatic attraction and ligand exchange. These results suggest that after modification, acid-activated akadama clay could be used as a promising adsorbent for phosphate removal from wastewater in real application and then further used as fertilizers.

Microcystin accumulation and biochemical responses in the edible clam Corbiculaleana P. exposed to cyanobacterial crude extract.

We investigated the accumulation and effects of cyanobacterial crude extract (CCE) containing microcystins (MCs) on the edible clam Corbiculaleana P. Toxic effects were evaluated through the activity of antioxidant and detoxification enzymes: catalase (CAT), superoxide dismutase (SOD), and glutathione-S-transferases (GSTs) from gills, foot, mantle and remaining soft tissues. Clams were exposed to CCE containing 400µg MC-LReq/L for 10days and were then kept in toxin-free water for 5days. Clam accumulated MCs (up to 3.41±0.63µg/g dry weight (DW) of unbound MC and 0.31±0.013µg/g DW of covalently bound MC). Detoxification and antioxidant enzymes in different organs responded differently to CCE during the experiment. The activity of SOD, CAT, and GST in the gills and mantle increased in MC-treated clams. In contrast, CAT and GST activity was significantly inhibited in the foot and mostly only slightly changed in the remaining tissues. The responses of biotransformation, antioxidant enzyme activity to CCE and the fast elimination of MCs during depuration help to explain how the clam can survive for long periods (over a week) during the decay of toxic cyanobacterial blooms in nature.

[Measures to Raise Awareness on Home Care Medicine for Staff at an Acute Medical Care Facility - Multi-Professional Collaboration on the Strengths Dissemination Project].

Kohka Public Hospital(KPH)focuses primarily on the treatment of acute diseases. However, as the only general hospital in the medical district and established under the National Health Insurance, KPH has a mandate in comprehensive medical care. With the aim of becoming a hospital that can cope with the anticipated super-aging society, a meeting was started to raise staff awareness of home care medicine. Senior managers were placed in each team along with staff with no involvement on the issue. Initially, a SWOT analysis was conducted to understand the current status. Views raised in the meetings will be summarized, and consequent measures will be announced both internally and externally as part of the Strengths Dissemination Project. Interest in home care medicine at acute medical care hospitals is undeniably low, but the reality is that many do not know how to get involved due to the lack of exposure. It is unquestionable that the need for home care medicine and regional cooperation will rise in our nation. We must direct the attention of health care providers there and start discussions.

Association of computed tomography-derived muscle mass and quality with delayed acquisition independent walking after cardiovascular surgery.

BACKGROUND: In the context of cardiovascular surgery, the foremost concern lies in delayed functional recovery, as typified by the acquisition of independent walking after surgery, among older patients with decline in skeletal muscle mass and quality. Computed tomography (CT), which is typically employed for the preoperative assessment of pathological conditions in patients undergoing cardiovascular surgery, is also suitable for screening for potential decline in skeletal muscle mass and quality. The aim of this study was to examine the predictive capabilities of CT-derived parameters such as muscle mass and muscle quality for the delayed acquisition of independent walking in the postoperative period. METHODS: This retrospective study enrolled consecutive Japanese patients who underwent elective cardiovascular surgery between May 2020 and January 2023. In total, 139 patients were included in the analyses. Based on the preoperative CT image, the psoas muscle volume index (PMVI) and psoas muscle attenuation (PMA) were calculated. Information on patient characteristics, including preoperative physical fitness such as handgrip strength/body mass index (GS/BMI), short physical performance battery (SPPB), and 6-min walking distance (6MWD), were obtained from the medical records. We defined delayed acquisition of independent walking after surgery as the inability to walk 100 m within 4 days after surgery. RESULTS: The median age of the patients was 72 (interquartile: 64-78) years, and 74.8% (104/139) were men; 47.5% corresponded to the delayed group. The areas under the curves of SPPB, GS/BMI, 6MWD, PMVI, and PMA against delayed acquisition of independent walking after surgery were 0.68 [95% confidence interval (CI): 0.59 to 0.77], 0.72 (95% CI: 0.63 to 0.80), 0.73 (95% CI: 0.65 to 0.82), 0.69 (95% CI: 0.60 to 0.78), and 0.78 (95% CI: 0.70 to 0.85), respectively. In the multivariate logistic regression analysis, low PMA was significantly associated with delayed acquisition of independent walking even after adjustment for patient characteristics including physical fitness [model 1: SPPB (OR, 1.14; 95% CI: 1.03-1.25), model 2: GS/BMI (OR, 1.13; 95% CI: 1.03-1.25), and model 3: 6MWD (OR, 1.14; 95% CI: 1.03-1.25)], but PMVI was not. CONCLUSIONS: Our study revealed a strong association between PMA, a marker of CT-derived muscle quality, and the postoperative delay in achieving independent walking in patients who underwent cardiovascular surgery. The technique to obtain information on muscle quality during the time period before surgery may be an option for timely therapeutic intervention in patients who may have delayed acquisition of independent walking after surgery.

Increased Prorenin Expression in the Kidneys May Be Involved in the Abnormal Renal Function Caused by Prolonged Environmental Exposure to Microcystin-LR.

Toxic algae in eutrophic lakes produce cyanotoxic microcystins. Prior research on the effect of microcystin-LR in the kidney utilized intraperitoneal injections, which did not reflect natural exposure. Oral microcystin-LR research has focused on renal function and histopathology without examining the molecular mechanisms. The present study aimed to evaluate the mechanism of microcystin-LR in the kidneys via oral administration in WKAH/HkmSlc rats over 7 weeks, alongside stimulation of the proximal tubular cells. Although there were no differences in the concentrations of plasma albumin, blood urea nitrogen, and creatinine, which are parameters of renal function, between the control and microcystin-LR-administrated rats, prorenin expression was significantly increased in the renal cortex of the rats administered microcystin-LR and the microcystin-LR-treated proximal tubular cells. The expression levels of (pro)renin receptor (PRR), transforming growth factor-ß1 (TGFß1), and α-smooth muscle actin (α-SMA) in the renal cortex did not differ significantly between the control and microcystin-LR-administered rats. However, the expression levels of prorenin were significantly positively correlated with those of PRR, TGFß1, and α-SMA in the renal cortex of rats administered microcystin-LR. Additionally, a significant positive correlation was observed between the expression levels of TGFß1 and α-SMA. Collectively, increased prorenin expression caused by the long-term consumption of microcystin-LR may initiate a process that influences renal fibrosis and abnormal renal function by regulating the expression levels of PRR, TGFß1, and α-SMA.

Degradation of microcystins by an electrochemical oxidative electrode cell.

Microcystins (MCs), which are produced by cyanobacteria, are one of the most serious problems that threaten quality of drinking water and public health. In this study, an electrolysis cell with no electrolyte is demonstrated to degrade MCs (MC-RR, MC-YR and MC-LR) in both high and low concentrations. In addition, degradation of MCs was studied under different current densities. The results revealed that the electrolysis cell could degrade MCs successfully. It was observed that degradation of a single MC was faster than mixed types and statistical analysis revealed that the degradation rate of all the three MCs did not show much difference in mixed degradation. Analysis of hydroxyl radical concentration suggested a possible role of the hydroxyl radical in degradation of MCs. We propose that the electrolysis cell could be a promising treatment for effective removal of MCs in situ, especially in water purification plants where low amounts of salts (electrolytes) are present.

Pb(II) bioremediation using fresh algal-bacterial aerobic granular sludge and its underlying mechanisms highlighting the role of extracellular polymeric substances.

Lead (Pb) discharged from rural industries poses a significant threat to the environment and human health. Algal-bacterial aerobic granular sludge (A-B AGS) is a promising alternative for sewage treatment with high efficiency and good settleability. In this study, Pb(II) biosorption using fresh A-B AGS was investigated for the first time. The important role of extracellular polymeric substances (EPS) was revealed with the involved mechanisms being clarified. The desorbents for Pb recovery from Pb-loaded A-B AGS were also screened. Results showed that A-B AGS has an excellent maximum Pb adsorption capacity of 72.4 mg·g-1 at pH 6.0. EPS plays an important role in keeping microbial activity, Pb bonding, and providing metal ions (Ca, Na and Mg) for Pb ion exchanges. Electrostatic interaction, ion exchange, and bonding to functional groups may occur orderly in the Pb biosorption process and the formation of pyromorphite (Pb5(PO4)3Cl) contributes to Pb biosorption. About 66 % of the adsorbed Pb was accumulated in the A-B AGS microbial cells. Na2EDTA (0.05 M) can recover 60.3 % of the loaded Pb with the highest microbial activity of granules being remained. All the findings will provide the theoretical basis for the large-scale application of A-B AGS to bioremediate Pb(II)-containing wastewater.

Use of nanobubble water bioaugmented anaerobically digested sludge for high-efficacy energy production from high-solids anaerobic digestion of corn straw.

An increasing attention has been paid to the secure and sustainable management of agricultural wastes, especially lignocellulosic biomass. Nanobubble water (NBW) contains 106-108 bubbles/mL with diameter <1000 nm. Although previous studies have examined the enhancement effects of NBW on methane production from organic solid wastes, the NBW-based anaerobic digestion (AD) system is still restrained from practical application due to the large increase in AD reactor volume, generation of wastewater, and increase in energy consumption as well. In this study, NBW bioaugmentation of anaerobically digested sludge for the first time was performed for high-solids AD of corn straw. Results show that cellulase, xylanases and lignin peroxidase activities were increased by 2-55% during the NBW bioaugmentation process. Significant enrichment of hydrolytic/acidogenic bacteria and methanogenic archaea were noticed in the NBW bioaugmented sludge. This study clearly demonstrated 47% increase in methane production from high-solids AD of corn straw when O2-NBW bioaugmented sludge was applied, achieving a net energy gain of 5138 MJ/t-volatile solids of corn straw with an energy recovery of 34%. The NBW-based high-solids AD system can provide a novel and sustainable management solution for renewable energy production from agricultural wastes, targeting the reduction of environmental pollution and energy crisis.

Enhanced economic benefit of recycling Fe3O4 for promotion of volatile fatty acids production in anaerobic fermentation of food waste.

Fe3O4 addition in anaerobic fermentation of food waste (FW) is promising for enhancing volatile fatty acids (VFAs) production. However, the large amount of Fe3O4 in the digestate fertilizer leads to the waste of resources and possible toxicity to organisms. Thus, this study investigated the feasibility of Fe3O4 recycling for VFAs enhancement in anaerobic fermentation of FW and performed the cost-benefit evaluation of this process. Results revealed that Fe3O4 could be successfully recycled twice with recovery rates of 71.5% and 65.5%, respectively. X-ray diffraction analysis revealed a slight change to the Fe2O3-like structure after 2-time recycling. The VFAs yields were enhanced by 17.2% and 17.0% in Cycles 1 and 2 owing to the enhanced activities of hydrolytic and acid-forming enzymes. The net income of the Fe3O4 recycling process was about 13-fold higher than that of the conventional treatment process, suggesting a promising and economically feasible strategy for enhancing VFAs production.

Enhanced fixation of dissolved inorganic carbon by algal-bacterial aerobic granular sludge during treatment of low-organic-content wastewater.

The microalgae-based wastewater treatment technologies are believed to contribute to carbon neutrality. This study investigated the inorganic carbon fixation performance in the algal-bacterial aerobic granular sludge (A-BAGS) process under cultivation at different concentrations of organic carbon (OC) and inorganic carbon (IC). The results indicated that A-BAGS in treating wastewater containing organics of 77 mg-C/L contributed little to the fixation of inorganic carbon, while the highest inorganic carbon removal efficiency of 50 % was achieved at the influent IC of 100 mg/L and OC of 7 mg/L. This high IC condition contributed to enhanced biomass growth rate and enhanced extracellular polymeric substances, while it did not affect the granular stability and nitrification efficiency. The microbial diversity was also largely enhanced. The results demonstrated the great potential of A-BAGS for simultaneous resource recovery in wastewater and inorganic carbon fixation, while operation conditions need to be further optimized.

Photosynthetic oxygen-supported algal-bacterial aerobic granular sludge can facilitate carbon, nitrogen and phosphorus removal from wastewater: Focus on light intensity selection.

Photosynthetic O2 is a promising alternative for mechanical aeration, the major energy-intensive unit in wastewater treatment plants. This study aimed to investigate the effects of light intensity varied from 190 to 1400 µmol·s-1·m-2 on photosynthetic O2-supported algal-bacterial aerobic granular sludge (AGS) system. Results indicate photosynthetic O2 can implement aerobic phosphorus (P) uptake and ammonia oxidation under the test illumination range even at dissolved oxygen concentration < 0.5 mg/L. An obvious O2 accumulation occurred after 60-90% nutrients being removed under 330-1400 µmol·s-1·m-2, and highly efficient ammonia removal, P uptake, and dissolved inorganic carbon removal were achieved under 670-1400 µmol·s-1·m-2. On the other hand, photosynthesis as O2 supplier showed little effect on major ions except for K+. This study provides a better understanding of the roles of light intensity on photosynthetic O2-supported algal-bacterial AGS system, targeting a sustainable wastewater industry.

Enhanced alginate-like exopolymers recovery from algal-bacterial aerobic granular sludge: Optimal cultivation condition and contribution of bacteria and microalgae during the transport/storage period.

Extracting alginate-like exopolymers (ALE) is a promising approach for valuable resources recovery from excess algal-bacterial aerobic granular sludge (AGS) to achieve circular bioeconomy and environmental sustainability in wastewater treatment plants (WWTPs). In this study, six batch cultivation tests were conducted to investigate the optimal cultivation duration or transport/storage period, light intensity, and temperature for algal-bacterial AGS after sampling and before further processing or ALE extraction. At a light intensity of 5 klux, the highest ALE content (36.33 mg/g-VSS) was detected at a low temperature of 10 °C, which increased by 300% from its original level after 6-h cultivation. Results from levofloxacin (LVX) exposure and dark condition imply that microalgae contributed more to ALE synthesis in the algal-bacterial granules. This work not only provides a better understanding of the mechanisms involved in ALE biosynthesis but also offers useful guidance for maintaining or improving ALE recovery after algal-bacterial biomass sampling.

Revealing calcium ion behavior during anaerobic phosphorus release process in aerobic granular sludge system.

Calcium ions (Ca2+) are important for biological phosphorus (P) removal from wastewater, but its behavior has not been well documented during the anaerobic P release process. This study is aimed to explore the mechanisms of Ca2+ release in bacterial aerobic granular sludge (AGS) system. During the non-aeration (anaerobic) phase, nearly 40 % increase in Ca2+ concentration was detected at the bottom of AGS reactor where decrease in pH and increase in Mg2+ concentration occurred. The pH decrease due to anaerobic P release caused CaCO3 dissolution inside the granules, leading to Ca2+ release. In addition, the increased Mg2+ ions from hydrolysis of polyphosphates were detected to reversibly exchange with Ca2+ in granules at a molar ΔCa/ΔMg ratio of 0.51-0.65. Results from this work revealed that dissolution of CaCO3 and ions exchange between Ca2+ and Mg2+ were the two major contributors to Ca2+ release during anaerobic P release process.