A novel method of identifying estuary high-nutrient zones for water quality management.

Coastal shallow waters are highly vulnerable to pollution, often leading to the development of intricate eutrophication zones. However, accurately determining these areas poses a significant challenge due to the complex interplay of estuarine hydrodynamics and nutrient transformation. To address such issue, a novel method was proposed to identify high-nutrient zones through calculating the continuous zonation of released tracers when their instantaneous concentrations declined to 1/e of their initial values. The method was well tested using idealized estuary models with varying shape parameters, water depths and river discharges. The results consistently revealed that the boundaries of high-nutrient zones fell within the mixed zone, characterized by salinity levels of 10- 20 psu. In Shenzhen Bay, a typical shallow bay, distinct differences were observed in the concentrations of dissolved inorganic nitrogen (DIN) and PO43-. Both the 20 psu isohaline and the proposed method effectively identified the partition boundary of high DIN and PO43- in 2001-2010, but only the newly proposed method demonstrated accuracy in delineating the actual high-nutrient zone during the continuous nutrient reduction period from 2010 to 2020. This study provides a practical and feasible approach that can serve as an auxiliary decision-making tool for managing estuarine water environments, and it has potential to facilitate the implementation of timely and effective measures for pollution control.

Development of biocatalytic microbial ecosystem (FPUS@RODMs@In-PAOREs) for rapid and sustainable degradation of various refractory organics.

The removal of diverse refractory organics from complex industrial wastewater continues to be a challenge. Although biological treatments are commonly employed, only partial degradation and increasing emergence of nitrogenous compounds, i.e., nitrate (NO3) and nitrite (NO2) would pose severe toxicity to the intact microbes. Herein, an efficient biocatalytic microbial ecosystem (BCME) was designed over a porous bio-carrier made of a functional polyurethane sponge (FPUS). The BCME comprised a unique set of organisms (RODMs) with novel metabolism, efficiently degrading highly-concentrated aromatics. Strategic enzyme immobilization was utilized to introduce in-situ production and aggregation of the oxidation and reduction enzymes (In-PAOREs) onto the FPUS, thereby ensuing sustained functions of the RODMs community. The developed FPUS@RODMs@In-PAOREs system was found to enhance the refractory organics removal rate to 4 kg/m3/day, and it would be attributed to the enzymatic catalysis of refractory organics (2000 mg/L) accompanied by the removal of COD (1200 mg/L) and nitrogenous compounds (200 mg/L). Besides, the fluctuating concentration of extra polymeric substances (EPS) played a dual role through enhancing adhesion, promoting the development of a functional microbial ecosystem, and creating an EPS gradient within the FPUS bio-carrier. This differential distribution of enzymes was established to significantly boost biocatalysis activity reaching 400 U/g VSS.

NbCZF1, a Novel C2H2-Type Zinc Finger Protein, as a New Regulator of SsCut-Induced Plant Immunity in Nicotiana benthamiana.

SsCut, which functions as an elicitor, can induce plant immunity. In this study, we utilized Nicotiana benthamiana and virus-induced gene silencing to decrease the expression of > 2,500 genes individually. Using this forward genetics approach, several genes were identified that, when silenced, compromised SsCut-triggered cell death based on a cell death assay. A C2H2-type zinc finger gene was isolated from N. benthamiana Sequence analysis indicated that the gene encodes a 27 kDa protein with 253 amino acids containing two typical C2H2-type zinc finger domains; this gene was named NbCZF1 We found that SsCut-induced cell death could be inhibited by virus-induced gene silencing of NbCZF1 in N. benthamiana In addition, SsCut induces stomatal closure, accompanied by reactive oxygen species (ROS) production by NADPH oxidases and nitric oxide (NO) production. NbCZF1-silenced plants showed impaired SsCut-induced stomatal closure, decreased SsCut-induced production of ROS and NO in guard cells and reduced SsCut-induced resistance against Phytophthora nicotianae Taken together, these results demonstrate that the NbCZF1-ROS-NO pathway mediates multiple SsCut-triggered responses, including stomatal closure, hypersensitive responses and defense-related gene expression. This is the first report describing the function of a C2H2-type zinc finger protein in N. benthamiana.