A biodegradable chitosan-based polymer for sustained nutrient release to stimulate groundwater hydrocarbon-degrading microflora.
作者: Jili Wang ; Yuling Zhang ; Ting Liu ; Yujia Shi ; Yang Ding ; Yi Zhang ; Weiqing Xu ; Xinying Zhang ; Yiliang Wang ; Dong Li
Petroleum hydrocarbon-contaminated groundwater often has a low indigenous microorganism population and lacks the necessary nutrient substrates for biodegradation reaction, resulting in a weak natural remediation ability within the groundwater ecosystem. In this paper, we utilized the principle of petroleum hydrocarbon degradation by microorganisms to identify effective nutrients (NaH2PO4, K2HPO4, NH4NO3, CaCl2, MgSO4·7H2O, FeSO4·7H2O, and VB12) and optimize nutrient substrate allocation through a combination of actual surveys of petroleum hydrocarbon-contaminated sites and microcosm experiments. Building on this, combining biostimulation and controlled-release technology, we developed a biodegradable chitosan-based encapsulated targeted biostimulant (i.e., YZ-1) characterized by easy uptake, good stability, controllable slow-release migration, and longevity to stimulate indigenous microflora in groundwater to efficiently degrade petroleum hydrocarbon. Results showed that YZ-1 extended the active duration of nutrient components by 5-6 times, with a sustainable release time exceeding 2 months. Under YZ-1 stimulation, microorganisms grew rapidly, increasing the degradation rate of petroleum hydrocarbon (10 mg L-1) by indigenous microorganisms from 43.03% to 79.80% within 7 d. YZ-1 can easily adapt to varying concentrations of petroleum hydrocarbon-contaminated groundwater. Specifically, in the range of 2-20 mg L-1 of petroleum hydrocarbon, the indigenous microflora was able to degrade 71.73-80.54% of the petroleum hydrocarbon within a mere 7 d. YZ-1 injection facilitated the delivery of nutrient components into the underground environment, improved the conversion ability of inorganic electron donors/receptors in the indigenous microbial community system, and strengthened the co-metabolism mechanism among microorganisms, achieving the goal of efficient petroleum hydrocarbon degradation.
2023-07-17·Probiotics and antimicrobial proteins
Probiotic Potential, Antibacterial, and Antioxidant Capacity of Aspergillus luchuensis YZ-1 Isolated From Liubao Tea.
作者: Xiyan Zhang ; Rui Jiao ; Hui Li ; Dexin Ou ; Danfeng Zhang ; Yizhong Shen ; Na Ling ; Yingwang Ye
Aspergillus fungi are widely used in the traditional fermentation of food products, so their safety risks and functions are worthy of investigation. In this study, one Aspergillus luchuensis YZ-1 isolated from Liubao tea was identified based on phylogenetic analyses of sequences of three genes coding for internal transcribed spacer 1 (ITS1), β-tubulin (benA), and calmodulin (CaM). The results of hemolytic activity, DNase activity, cytotoxicity assay, and antibiotic resistance assay indicated that the strain is potentially safe. The excellent gastrointestinal fluid tolerance, acid tolerance, bile tolerance, auto-aggregation, co-aggregation, cell surface hydrophobicity, and adhesion to human colon adenocarcinoma (HT29) cell line were observed on analysis of the probiotic properties. Furthermore, the results of the antibacterial activity of A. luchuensis YZ-1 indicated that the strain had strong antagonistic effects against Gram-negative and Gram-positive bacteria as well as fungi. Simultaneously, the water extracts and 80% ethanolic extracts of A. luchuensis YZ-1 cells also showed strong ABTS, DPPH, and OH- scavenging ability. Taken together, our results suggest that A. luchuensis YZ-1 has desirable functional probiotic properties and can be proposed as a biocontrol agent in the food industry.
1988-07-15·Journal of Immunology2区 · 医学
Synergistic interaction between complement receptor type 2 and membrane IgM on B lymphocytes
2区 · 医学
作者: Carter, Robert H. ; Spycher, Martin O. ; Ng, Yin C. ; Hoffman, Robert ; Fearon, Douglas T.
We sought biochemical evidence for a role of C receptors types 1 (CR1) and 2 (CR2) in B cell activation. A flow cytometer was used to measure the fluorescence of tonsillar cells that had been loaded with the calcium-dependent indicator indo-1, and cells were stimulated by cross-linking cell-bound DA4.4 anti-IgM, Yz-1 anti-CR1 or HB5 anti-CR2 with goat anti-mouse IgG. There was a direct dose-response relationship between the proportion of cells having increased cytoplasmic free calcium concentration (Cai) after addition of second antibody and the amount of cell-bound Fab' DA4.4. In contrast, no rise in Cai was observed after cross-linking bound Yz-1 or HB5. To determine whether CR1 or CR2 could modify the increase in Cai induced by cross-linking membrane IgM, Cai was monitored after addition of second antibody to cells bearing combinations of either Yz-1 or HB5 with a limited amount of DA4.4. The combination of Yz-1 with DA4.4 yielded little or no further increase in the percentage of cells responding to cross-linking with elevated Cai compared with DA4.4 alone. However, the combination of HB5 with limited DA4.4 synergistically enhanced this response, resulting in stimulation that was equivalent to that obtained with optimal concentrations of DA4.4. The synergistic effect of CR2 was also observed with avidin as the cross-linking reagent for bound biotinylated HB5 and DA4.4, occurred in the presence of EGTA, and did not require T cells. Studies of the proliferation of B cell-enriched PBMC demonstrated that, whereas HB5 coupled to Sepharose alone induced little or no DNA synthesis, the combination of HB5 with limited DA4.4 on Sepharose induced a dose-related synergistic increase in the incorporation of [3H]thymidine.