Advances in Stem Cell-Based Therapies in the Treatment of Osteoarthritis.

Osteoarthritis (OA) is a chronic, degenerative joint disease presenting a significant global health threat. While current therapeutic approaches primarily target symptom relief, their efficacy in repairing joint damage remains limited. Recent research has highlighted mesenchymal stem cells (MSCs) as potential contributors to cartilage repair, anti-inflammatory modulation, and immune regulation in OA patients. Notably, MSCs from different sources and their derivatives exhibit variations in their effectiveness in treating OA. Moreover, pretreatment and gene editing techniques of MSCs can enhance their therapeutic outcomes in OA. Additionally, the combination of novel biomaterials with MSCs has shown promise in facilitating the repair of damaged cartilage. This review summarizes recent studies on the role of MSCs in the treatment of OA, delving into their advantages and exploring potential directions for development, with the aim of providing fresh insights for future research in this critical field.

Effect of different size microplastic particles on the construction of algal-bacterial biofilms and microbial communities.

Algal-bacterial symbiotic system is a biological purification system that combines sewage treatment with resource utilization and has the dual effects of carbon sequestration and pollution reduction. In this study, an immobilized algal-bacterial biofilm system was constructed for the treatment of natural sewage. Effects of exposure to microplastics (MPs) with different particle diameters (0.065 µm, 0.5 µm and 5 µm) were determined in terms of algal biomass recovery efficiency, the composition of extracellular polymeric substances (EPS) and morphologic characteristics. The impacts of MPs on the bacterial diversity and community structure of biofilms were also examined. The metagenomic analysis of key microorganisms and related metabolism pathways involved in system was further investigated. Results showed that following exposure to 5 µm MP, a maximum algal recovery efficiency of 80% was achieved, with a minimum PSII primary light energy conversion efficiency (Fv/Fm ratio) of 0.513. Furthermore, 5 µm MP caused the highest level of damage to the algal-bacterial biofilm, enhancing the secretion of protein-rich EPS. The biofilm morphology became rough and loose following exposure to 0.5 µm and 5 µm MP. Community diversity and richness were significantly high in biofilms exposed to 5 µm MP. Proteobacteria (15.3-24.1%), Firmicutes (5.0-7.8%) and Actinobacteria (4.2-4.9%) were dominant in all groups, with exposure to 5 µm MP resulting in the highest relative abundance for these species. The addition of MPs promoted the related metabolic functions while inhibited the degradation of harmful substances by algal-bacterial biofilms. The findings have environmental significance for the practical application of algal-bacterial biofilms for sewage treatment, providing novel insights into the potential effects of MPs on immobilized algal-bacterial biofilm systems.

Characterization and seasonal variation in biofilms attached to leaves of submerged plant.

The microorganisms and functional predictions of leaf biofilms on submerged plants (Vallisneria natans (Val)) and in water samples (surface water (S) and bottom water (B)) in different seasons were evaluated in this study. S and B groups had 3249 identical operational taxonomic units (OTUs) (50.03%), while the Val group only had 1201 (18.49%) unique OTUs. There was significant overlap between microbial communities of S and B groups in the same season, while Val group showed the greater diversity. The dominant microbial clades were Proteobacteria (18.2-47.3%), Cyanobacteria (3.74-39.3%), Actinobacteria (1.64-29.3%), Bacteroidetes (1.31-21.7%), and Firmicutes (1.10-15.72%). Furthermore, there was a significant relationship between total organic carbon and the distribution of microbial taxa (p = 0.047), and TN may have altered the status of Cyanobacteria by affecting its biological nitrogen fixation capacity and reproductive capacity. The correlation network analysis results showed that the whole system consisted of 249 positive correlations and 111 negative correlations, indicating strong interactions between microbial communities. Functional predictions indicated that microbial functions were related to seasonal variation. These findings would guide the use of submerged plants to improve the diversity and stability of wetland microbial communities.

Seasonal changes driving shifts of aquatic rhizosphere microbial community structure and the functional properties.

Ecological floating beds could enable roots to become suspended and this allowed submerged roots to harbour various types of microbes. But, there was a lack of systematic research on microbial community structure changes and the influencing mechanisms. In this study, the ecological floating beds were constructed using selected plants [Cyperus involucratus Rottboll (Cyp), Thalia dealbata Fraser (Tha) and Iris tectorum Maxim (Iri)] that was compared with a control group [static water (S)]. The results showed that the highest abundance and diversity of root microbial communities were found in autumn, with the dominant taxa being Proteobacteria, Actinobacteriota, Cyanobacteria, Chloroflexi, Firmicutes, Bacteroidota, and Acidobacteriota. The microbial communities of Tha and Cyp groups greatly overlapped, while the Iri and control groups exhibited distinctly diverse communities. The root microbial populations of the same plant also reflected a large change in different seasons. Conversely, photosynthetic autotrophs and specialized anaerobes were more inclined to thrive at higher temperatures and lower DO concentrations and then they gradually became the dominant species. Microbial co-occurrences of the Tha and control groups were complex and showed both cooperation and competition. In addition, TOC was an important environmental factor that shaped the microbial community structures and DO changed the microbial community by affecting the abundance of aerobic and anaerobic bacteria. Microorganisms showed potential for degradation and metabolism of non-food substances with low/no corresponding metabolic pathways.

Development of model simulation based on BioWin and dynamic analyses on advanced nitrate nitrogen removal in deep bed denitrification filter.

A pilot-scale deep bed denitrification filter using quartz sand as the filter media was operated under filtration velocity of 5.23 m/h. Nitrate, nitrite, ammonia, and total nitrogen removal rates were relatively high at influent C/N ratios of 4:1 and 5:1. A model was developed using software to simulate the processes operating in the filter and improve the related parameters in the actual operations. The normalized sensitivity coefficient and the mean square sensitivity measure were used for the sensitivity analysis. Results showed that the stoichiometric parameters were the most sensitive, which were related to methylotrophs and biofilm. Measured data were consistent with the simulations. Moreover, the order of significance of factors affecting nitrate nitrogen removal was as follows: influent chemical oxygen demand, influent nitrate nitrogen, and hydraulic retention time. Last, the denitrification dynamic model was obtained at influent C/N ratio of 5:1.

Advanced nitrogen removal from municipal wastewater treatment plant secondary effluent using a deep bed denitrification filter.

With the improvement of wastewater discharge standards, wastewater treatment plants (WWTPs) are continually undergoing technological improvements to meet the evolving standards. In this study, a quartz sand deep bed denitrification filter (DBDF) was used to purify WWTP secondary effluent, utilizing high nitrate nitrogen concentrations and a low C/N ratio. Results show that more than 90% of nitrate nitrogen (NO3-N) and 75% of chemical oxygen demand (COD) could be removed by the 20th day of filtration. When the filter layer depth was set to 1,600 mm and the additional carbon source CH3OH was maintained at 30 mg L-1 COD (20 mg L-1 methanol), the total nitrogen (TN) and COD concentrations of DBDF effluent were stabilized below 5 and 30 mg L-1, respectively. Analysis of fluorescence revealed that DBDF had a stronger effect on the removal of dissolved organic matter (DOM), especially of aromatic protein-like substances. High throughput sequencing and qPCR results indicate a distinctly stratified microbial distribution for the main functional species in DBDF, with quartz sand providing a good environment for microbes. The phyla Proteobacteria, Bacteroidetes, and Chloroflexi were found to be the dominant species in DBDF.

Validation and application of an analytical method for the determination of selected acidic pharmaceuticals and estrogenic hormones in wastewater and sludge.

This study was undertaken to develop an extraction method for seven acidic pharmaceuticals and five steroidal estrogens from wastewater, treated wastewater and sludge samples. The temperature and time of sample derivatization using N,O-bis(trimethylsilyl)trifluoroacetamide was optimized. Our results show that pretreatment combined with solid phase extraction (SPE) for wastewater samples (using an ENVI-C18 cartridge) and liquid-solid extraction combined with SPE (using an HLB cartridge) for sludge samples increased the analytical efficiency for acidic pharmaceuticals and estrogenic hormones using gas chromatography-mass spectrometry (GC-MS). The derivatization conditions were optimized at 40°C for 2 h. In addition, the derivatized samples were stable at ambient temperature. The new method was validated and applied to the analysis of real wastewater and discharged sludge samples from a local wastewater treatment plant. Except for 17α-ethinylestradiol, all acidic pharmaceuticals and estrogens were detected in the influent, effluent and discharged sludge samples. The concentrations of these compounds were particularly high in the discharged sludge samples.

Coupled effects of redox-active substances and microbial communities on reactive oxygen species in rhizosphere sediments of submerged macrophytes.

Reactive oxygen species (ROS) play crucial roles in element cycling and pollutant dynamics, but their variations and mechanisms in the rhizosphere of submerged macrophytes are poorly investigated. This study investigated the light-dark cycle fluctuations and periodic variations in ROS, redox-active substances, and microbial communities in the rhizosphere of Vallisneria natans. The results showed sustained production and significant diurnal fluctuations in the O2•- and •OH from 27.6 ± 3.7 to 61.7 ± 3.0 µmol/kg FW and 131.0 ± 6.8 to 195.4 ± 8.7 µmol/kg FW, respectively, which simultaneously fluctuated with the redox-active substances. The ROS contents in the rhizosphere were higher than those observed in non-rhizosphere sediments over the V. natans growth period, exhibiting increasing-decreasing trends. According to the redundancy analysis results, water-soluble phenols, fungi, and bacteria were the main factors influencing ROS production in the rhizosphere, showing contribution rates of 74.0, 17.3, and 4.4 %, respectively. The results of partial least squares path modeling highlighted the coupled effects of redox-active substances and microbial metabolism. Our findings also demonstrated the degradation effect of ROS in rhizosphere sediments of submerged macrophytes. This study provides experimental evidence of ROS-related rhizosphere effects and further insights into submerged macrophytes-based ecological restoration.

Microbial communities and mobile genetic elements determine the variations of antibiotic resistance genes for a continuous year in the urban river deciphered by metagenome assembly.

Antibiotic resistance genes (ARGs) have become emerging environmental contaminants influenced by intricate regulatory factors. However, there is a lack of comprehensive studies on the evolution and distribution of ARGs over a full year in urban rivers, which serve as significant reservoirs of ARGs due to dynamic human activities. In this study, we conducted a 12-month metagenomic assembly to explore the microbial communities, ARGs, mobile genetic elements (MGEs) coexisting with ARGs, ARGs hosts, and the impact of environmental factors. Bacitracin (32%-47%) and multidrug (13%-24%) were detected throughout the year, constituting over 60% of the total abundance, making them the primary ARGs types. The assembly mechanisms of microbial communities and ARGs were primarily driven by stochastic processes. Integrase, IntI1, recombinase, and transposase were identified as the main MGEs coexisting with ARGs. Procrustes analysis revealed a significant structural association, indicating that the composition of host communities likely plays crucial roles in the seasonal composition and distribution of ARGs. Human pathogenic bacteria (HPBs) were identified in the summer, autumn, and winter, with Escherichia coli, Klebsiella pneumoniae, Acinetobacter lwoffii, and Burkholderiales bacterium being the primary HPBs. Mantle tests and PLS-PM equation analysis indicated that microbial communities and MGEs are the most critical factors determining the distribution and composition of ARGs in the river. Environmental factors (including water properties and nutrients) and ARGs hosts influence the evolution and abundance of ARGs by directly regulating microbial communities and MGEs. This study provides critical insights into risk assessment and management of ARGs in urban rivers.

The coupling effect promotes superoxide radical production in the microalgal-fungal symbiosis systems: Production, mechanisms and implication for Hg(II) reduction.

Redox transformation of mercury (Hg) is critical for Hg exchange at the air-water interface. However, the superoxide radicals (O2•─) contribution of microalgal-fungal symbiotic systems in lake water to Hg(II) reduction is mainly unknown. Here, we studied the enhanced potential for O2•─ production by the coupling effect between microalgae and fungi. The relationships between microenvironment, microorganisms, and O2•─ production were also investigated. Furthermore, the implication of O2•─ for Hg(II) reduction was explored. The results showed that the coupling effect of microalgae and fungi enhanced O2•─ generation in the symbiotic systems, and the O2•─ generation peaked on day 4 in the lake water at 160.51 ± 13.06-173.28 ± 18.21 µmol/kg FW (fresh weight). In addition, O2•- exhibited circadian fluctuations that correlated with changes in dissolved oxygen content and redox potential on the inter-spherical interface of microalgal-fungal consortia. Partial least squares path modeling (PLS-PM) indicates that O2•─ formation was primarily associated with microenvironmental factors and microbial metabolic processes. The experimental results suggest that O2•─ in the microalgal-fungal systems could mediate Hg(II) reduction, promoting Hg conversion and cycling. The findings highlight the importance of microalgae and fungal symbiotic systems in Hg transformation in aquatic environments.

Interplay between COVID-19 and Secukinumab treatment in Spondylarthritis patients during the omicron surge: a retrospective cohort study.

The objective of this retrospective cohort study was to assess the relationship between Corona Disease 2019 (COVID-19) and Secukinumab treatment in patients with Spondylarthritis (SpA) in China during the omicron surge. Researchers retrieved 1018 medical records of Secukinumab-treated patients between January 2020 and January 2023 from the West China Hospital of Sichuan University. Out of these, 190 SpA patients from the rheumatology clinic were selected for the study. Guided phone questionnaires were administered by research staff to collect baseline characteristics, SpA disease status, and COVID-19 clinical outcomes. Cohabitants served as the control group and provided COVID-19 related data. Of the 190 potential SpA patients, 122 (66%) completed the questionnaire via phone, along with 259 cohabitants. 84.4% of SpA patients were diagnosed with Ankylosing Spondylitis (AS), and 15.6% were diagnosed with Psoriatic Arthritis (PsA). The rate of SARS-CoV-2 infection was 83.6% in the Secukinumab group and 88.8% in the cohabitants control group, with no significant difference (OR = 0.684, CI 0.366-1.275). One instance of severe COVID-19 was observed in the Secukinumab group, while two were identified in the cohabitants control group. Patients in the Secukinumab group had less time with fever caused by COVID-19 (p = 0.004). Discontinuing Secukinumab after SARS-CoV-2 infection did not significantly affect the course of COVID-19 or worsen SpA status according to our data. Our study suggests that administering Secukinumab to SpA patients does not increase their susceptibility to contracting SARS-CoV-2, and may have a positive effect on the course of SARS-CoV-2 infection.

COVID-19 in Systemic Lupus Erythematosus patients treated with belimumab: a retrospective clinical study.

BACKGROUND: Routine use of immunosuppressive agents in systemic lupus erythematosus (SLE) patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) potentially increases the risk of adverse outcomes. belimumab, a monoclonal antibody for the treatment of SLE, remains untested for its specific impact on coronavirus disease 2019 (COVID-19) symptoms in these patients. Here, this research investigated the effect of belimumab on COVID-19 symptoms in SLE patients infected with SARS-CoV-2. METHODS: This study enrolled SLE patients who underwent treatment with belimumab. After thorough screening based on the inclusion and exclusion criteria, data pertaining to COVID-19 for both the participants and their cohabitants were obtained through telephone follow-up. The potential impact of belimumab on COVID-19 was evaluated by comparing COVID-19 symptoms and medication use across various groups to investigate the association between belimumab treatment and COVID-19 in SLE. RESULTS: This study involved 123 SLE patients, of whom 89.4% tested positive for SARS-CoV-2. Among cohabitants of SLE patients, the SARS-CoV-2 positive rate was 87.2% (p = 0.543). Patients treated with belimumab exhibited a lower incidence of multiple COVID-19 symptoms than their cohabitating counterparts (p < 0.001). This protective effect was found to be partially related to the time of last belimumab administration. Among those with COVID-19, 30 patients opted to discontinue their anti-SLE drugs, and among them, 53% chose to discontinue belimumab. Discontinuing drugs did not increase the risk of hospitalization due to SARS-CoV-2 infection. CONCLUSION: This study concluded that treatment with belimumab did not increase susceptibility to COVID-19 and beneficially alleviated the symptoms of COVID-19.

Gut microbiota dysbiosis characterized by abnormal elevation of Lactobacillus in patients with immune-mediated necrotizing myopathy.

Aim: The gut microbiota plays an important role in human health. In this study, we aimed to investigate whether and how gut microbiota communities are altered in patients with immune-mediated necrotizing myopathy (IMNM) and provide new ideas to further explore the pathogenesis of IMNM or screen for its clinical therapeutic targets in the future. Methods: The gut microbiota collected from 19 IMNM patients and 23 healthy controls (HCs) were examined by using 16S rRNA gene sequencing. Alpha and beta-diversity analyses were applied to examine the bacterial diversity and community structure. Welch's t test was performed to identify the significantly abundant taxa of bacteria between the two groups. Spearman correlation analysis was performed to analyze the correlation between gut microbiota and clinical indicators. A receiver operator characteristic (ROC) curve was used to reflect the sensitivity and specificity of microbial biomarker prediction of IMNM disease. P < 0.05 was considered statistically significant. Results: Nineteen IMNM patients and 23 HCs were included in the analysis. Among IMNM patients, 94.74% (18/19) of them used glucocorticoids, while 57.89% (11/19) of them used disease-modifying antirheumatic drugs (DMARDs), and the disease was accessed by MITAX (18.26 ± 8.62) and MYOACT (20.68 ± 8.65) scores. Participants in the groups were matched for gender and age. The diversity of the gut microbiota of IMNM patients differed and decreased compared to that of HCs (Chao1, Shannon, and Simpson indexes: p < 0.05). In IMNM patients, the relative abundances of Bacteroides, Roseburia, and Coprococcus were decreased, while that of Lactobacillus and Streptococcus were relatively increased. Furthermore, in IMNM patients, Lactobacillus was positively correlated with the levels of anti-signal recognition particle (SRP) antibodies, anti-Ro52 antibodies, and erythrocyte sedimentation rate (ESR), while Streptococcus was positively correlated with anti-3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) antibodies and C-reactive protein (CRP). Roseburia was negatively correlated with myoglobin (MYO), cardiac troponin T (cTnT), ESR, CRP, and the occurrence of interstitial lung disease (ILD). Bacteroides was negatively correlated with ESR and CRP, and Coprococcus was negatively correlated with ESR. Finally, the prediction model was built using the top five differential genera, which was verified using a ROC curve (area under the curve (AUC): 87%, 95% confidence interval: 73%-100%). Conclusion: We observed a characteristic compositional change in the gut microbiota with an abnormal elevation of Lactobacillus in IMNM patients, which was accompanied by changes in clinical indicators. This suggests that gut microbiota dysbiosis occurs in IMNM patients and is correlated with systemic autoimmune features.

[Effects of electrical stimulation of sciatic nerve on synaptic plasticity of spinal dorsal horn, hippocampal CA1 region and spinal c-fos, hippocampal CA1 region expression in neonatal rats].

OBJECTIVE: To explore the response to nociceptive stimuli in spinal cord of neonatal rat and observe the electrical stimulation of sciatic nerve on synaptic plasticity of spinal dorsal horn, hippocampal CA1 region and spinal c-fos, hippocampal CA1 region expression in neonatal rats. METHODS: The rats were divided into neonatal and adult groups. The evoked potentials of left spinal dorsal horn from T13-L1 and right hippocampal CA1 region were recorded. After conditional electric stimulations, the potential amplitudes were recorded. When the incubation period reached 120 min, D-AP5 was added to spinal cord of rats and resulting changes in field potential and c-fos expression were recorded. RESULTS: Long-term potentiation (LTP) in neonatal rats was mainly evoked by A-type nerve fibers whereas LTP in adult rats was mainly evoked by C-type nerve fibers. C-fos expression was significantly increased in superficial, deep layers of spinal dorsal horn, ventral horn and hippocampal CA1 region in neonatal rats. CONCLUSION: Pain signals change with age.

Effects of microplastics of different sizes on the Chlorella vulgaris - Ganoderma lucidum co-pellets formation processes.

The effects of different sized MPs on the formation process of algal-fungal co-pellets were studied. The results show that a maximum biomass recovery of 70.96% and a minimum Fv/Fm ratio of 0.463 reached with 5.000 µm-microplastics. Chlorella vulgaris cells and microplastics adhered evenly to the mycelia of Ganoderma lucidum. The contact angle decreased 24.02% and 34.68% with addition of 0.065 µm and 0.500 µm microplastics, respectively, compared to the control group, while the lowest crystallinity index (7.05%) was obtained with 0.065 µm-microplastics addition. Moreover, 5.000 µm microplastics promoted the extracellular polymeric substances (EPS) secretion, with the soluble polysaccharide content increasing by 40.50% and the soluble protein content increasing by 23.25% compared with the single algal-fungal system, while bound polysaccharides increased by 113.26% and bound proteins increased by 29.48%. The 5.000 µm microplastics also significantly promoted enzyme activity in the co-pellets. These results provide a theoretical basis for algal recovery in microplastic-containing water.

Responses of submerged plant Vallisneria natans growth and leaf biofilms to water contaminated with microplastics.

Microplastics pose a serious threat to ecological processes and environmental health. To evaluate the toxic effects of the exposure of microplastics on submerged plants and biofilms, eel grass (Vallisneria natans) was exposed to different concentrations of microplastics (10-50 mg L-1). The changes in microbial community on leaf biofilms were also tested. The results showed that the ratio of variable fluorescence to maximum fluorescence was largely unchanged, but the contents of chlorophyll a and b increased by 56.5% and 23.0% respectively. Different concentrations of exposure to microplastics effectively induced antioxidant responses, such as increasing the activities of superoxide dismutase, peroxidase and catalase, as well as increasing the activity of glutathione S-transferase and the contents of glutathione and malondialdehyde. In addition, the leaf flesh cells of Vallisneria natans showed some degree of organelle damage when examined by transmission electron microscopy. Moreover, a high-throughput sequencing analysis showed that the abundances and structure of the microbial community on the leaf biofilms were altered by exposure to microplastics. These results demonstrated that environmentally relevant concentrations of microplastics could disrupt homeostasis, induce effective defense mechanisms of Vallisneria natans and alter the biofilms in aquatic ecosystems.

Increasing oxytetracycline and enrofloxacin concentrations on the algal growth and sewage purification performance of an algal-bacterial consortia system.

Oxytetracycline (OTC) and enrofloxacin (EFX) pollution in surface water are very common. Using the algal-bacterial consortia system to remove antibiotics remains to be further studied. In this study, the algal growth and sewage purification performance were studied in an algal-bacterial consortia system with different concentrations of antibiotics. The enzyme activity, malondialdehyde content, chlorophyll-a content, extracellular polysaccharide, and protein content of algae were also tested. It was found that the algal growth was promoted by low-dose antibiotics, 21.83% and 22.11% promotion at 0.1 mg L-1 OTC and EFX, respectively. The nutrients and antibiotics removals of the low-dose groups (OTC <5 mg L-1, EFX <1 mg L-1) were not affected significantly. More than 70% of total organic carbon and total phosphorus, and 97.84-99.76% OTC, 42.68-42.90% EFX were removed in the low-dose groups. However, the algal growth was inhibited, and the nutrients removals performance also declined in the high-concentration groups (10 mg L-1 OTC, 5 mg L-1 EFX). The superoxide dismutase and catalase activity, and malondialdehyde content increased significantly (P < 0.05), indicating the increased activity of reactive oxygen species. In addition, the decreased chlorophyll-a content, thylakoid membrane deformation, starch granules accumulation, and plasmolysis showed that the algal physiological functions were affected. These results showed that the algal-bacterial consortia system was more suitable to treat low-concentration antibiotics and provided basic parameters for the consortia application.

The binding effect and photooxidation on oxytetracycline with algal extracellular polymeric substances and natural organic matter.

Surface water contains a large amount of dissolved organic matter (DOM). Interactions between DOM and micropollutants have a significant impact on micropollutant degradation. In this study, algal extracellular polymeric substances (EPS) and natural organic matter (NOM) were selected as two DOM sources and oxytetracycline (OTC) as a representative micropollutant. EPS was mainly composed of tryptophan and protein-like organics, while NOM was mainly composed of fulvic acid-like, humic acid-like, and hydrophobic acid components. In addition, OTC degradation significantly decreased when bound with EPS and the C=O and C-H bonds of CH2 or CH3 groups may be involved in binding EPS and OTC, respectively, while -COOH may be involved in the binding of NOM and OTC. Furthermore, triplet intermediates were found to play a major role in OTC photodegradation in both EPS and NOM, with the contribution calculated as 49.96% and 44.61%, respectively. Steady-state concentrations of 3EPS* in EPS and 3NOM* in NOM were 3.59 × 10-14 mol L-1 and 5.54 × 10-15 mol L-1, respectively. These results provide new insights into the degradation of antibiotic-containing wastewater in the natural environment or engineering applications.

Effects of exogenous vitamin B12 on nutrient removal and protein expression of algal-bacterial consortium.

Chlorella vulgaris and Bacillus licheniformis consortium was added to synthetic wastewater with exogenous vitamin B12. In the presence of 100 ng/L vitamin B12, removal efficiencies of TN, NH3-N, PO43-P, and COD were 80.1%, 76.8%, 87.9%, and 76.7%, respectively. The functional groups on the cell surface of the consortium, including -NH, -CH3, C=O, C=C, and P-O-C, increased with 100 ng/L vitamin B12. These functional groups improved the biological adsorption of the consortium; however, higher concentrations of vitamin B12 resulted in an occlusion of the functional groups. Furthermore, there were 5 significantly enriched protein pathways, namely carbon fixation in photosynthetic organisms; amino acid metabolic pathways; the pathway of one carbon pool by folate; nitrogen metabolism; and photosynthesis. Most proteins in these pathways were upregulated, which enhanced carbon fixation and photosynthesis in the algal cells. Simultaneously, B12 promoted significant upregulation of proteins associated with the quorum-sensing pathway, which promoted the interaction between algae and bacteria.