Influence of cadmium and microplastics on physiological responses, ultrastructure and rhizosphere microbial community of duckweed.

The combined contamination of heavy metals and microplastics is widespread in freshwater environments. However, there are few researches on their combined effects on aquatic plants. In this study, the effects of single and combined stress of 0.01 mg L-1 cadmium (Cd), 50 mg L-1 polyethylene and 50 mg L-1 polypropylene for 15 days on the physiological response, ultrastructure and rhizosphere microbial community of duckweed were investigated. The results showed that Cd and microplastics single or combined stress inhibited the growth of duckweed, shortened the root length and decreased the chlorophyll content. Compared with single Cd treatments, the combination of microplastics and Cd increased duckweed growth rate and increased superoxide dismutase activity and malondialdehyde content and reduced chloroplast structural damage, indicating that the combined stress could reduce the toxicity of heavy metals to duckweed. Through the study of rhizosphere microbial diversity, 1381 Operational Taxonomic Unit (OTUs) were identified and rich microbial communities were detected in the duckweed rhizosphere. Among them, the main microbial communities were Proteobacteria, Bacteroidetes, and Cyanobacteria. Compared with Cd single stress, the ACE and chao index of rhizosphere microbial community increased under combined stress, indicating that the diversity and abundance of microbial communities were improved after combined stress treatment. Our study revealed the effects of heavy metals and microplastics on aquatic plants, providing a theoretical basis for duckweed applications in complex water pollution.

Research on the Mechanisms of Plant Enrichment and Detoxification of Cadmium.

The heavy metal cadmium (Cd), as one of the major environmentally toxic pollutants, has serious impacts on the growth, development, and physiological functions of plants and animals, leading to deterioration of environmental quality and threats to human health. Research on how plants absorb and transport Cd, as well as its enrichment and detoxification mechanisms, is of great significance to the development of phytoremediation technologies for ecological and environmental management. This article summarises the research progress on the enrichment of heavy metal cadmium in plants in recent years, including the uptake, transport, and accumulation of Cd in plants. The role of plant roots, compartmentalisation, chelation, antioxidation, stress, and osmotic adjustment in the process of plant Cd enrichment are discussed. Finally, problems are proposed to provide a more comprehensive theoretical basis for the further application of phytoremediation technology in the field of heavy metal pollution.

The effect of chelating agents on iron plaques and arsenic accumulation in duckweed (Lemna minor).

Iron plaques have been found to limit the phytoremediation efficiency by reducing iron solubility, while chelating agents can increase the bioavailability of iron from Fe plaques to numerous terrestrial plants. However, the effects of chelating agents on Fe plaques along the As accumulation in aquatic plants remain unknown. In this study, the effects of five chelating agents (EDTA, DTPA, NTA, GLDA, and CA) on the As (As(III) or As(V)), phosphate, and iron uptake by iron plaques and duckweed (Lemna minor) were examined. The results showed that the chelating agents increased the As accumulation in L. minor plants by desorbing and mobilizing As from Fe plaques. The desorption rates of As(V) (As(III)) from the Fe plaques by the chelating agents were 5.26-8.77% (8.70-15.02%), and the plants/DCB extract ratios of As(V) (As(III)) increased from 2.63 ± 0.13 (1.97 ± 0.06) to the peak value of 3.38 ± 0.21 (2.70 ± 0.14) upon adding chelating agents. Besides, the addition of chelating agents increased the uptake of P and Fe by L. minor plants. This work provides a theoretical basis for the remediation of As-contaminated waters by duckweed with the help of chelating agents.

Research Progress of a Potential Bioreactor: Duckweed.

Recently, plant bioreactors have flourished into an exciting area of synthetic biology because of their product safety, inexpensive production cost, and easy scale-up. Duckweed is the smallest and fastest-growing aquatic plant, and has advantages including simple processing and the ability to grow high biomass in smaller areas. Therefore, duckweed could be used as a new potential bioreactor for biological products such as vaccines, antibodies, pharmaceutical proteins, and industrial enzymes. Duckweed has made a breakthrough in biosynthesis as a chassis plant and is being utilized for the production of plenty of biological products or bio-derivatives with multiple uses and high values. This review summarizes the latest progress on genetic background, genetic transformation system, and bioreactor development of duckweed, and provides insights for further exploration and application of duckweed.

Joint effects of naphthalene and microcystin-LR on physiological responses and toxin bioaccumulation of Landoltia punctata.

The co-contamination of naphthalene (NAP) and microcystin-LR (MC-LR) commonly occurs in eutrophic waters. However, the joint effects of NAP and MC-LR on plants in aquatic environments remain unknown. Landoltia punctata is characterized by high starch yields and high biomass in polluted waters and has been proven to be a bioenergy crop and phytoremediation plant. In this study, L. punctata was cultured in a nutrient medium with environmentally relevant NAP (0.1, 1, 3, 5, and 10 µg/L) and MC-LR (5, 10, 25, 50, and 100 µg/L) to determine individual and joint toxic effects. The effects of NAP and MC-LR on physiological responses of L. punctata, including growth, starch accumulation, and antioxidant responses, were studied. Bioaccumulation of MC-LR in L. punctata, with or without NAP, was also examined. The results showed that growth and chlorophyll-a contents of L. punctata were reduced at high concentrations of MC-LR (≥ 25 µg/L), NAP (≥ 10 µg/L) and their mixture (≥ 10 + 1 µg/L) after exposure for 7 d. Starch accumulation in L. punctata did not decrease when exposed to NAP and MC-LR, and higher starch content of 29.8 % ± 2.7 % DW could be due to the destruction of starch-degrading enzymes. The antioxidant responses of L. punctata were stronger after exposure to MC-LR + NAP than when exposed to a single pollutant, although not enough to avoid oxidative damage. NAP enhanced the bioaccumulation of MC-LR in L. punctata when NAP concentration was higher than 5 µg/L, suggesting that higher potentials of MC-LR phytoremediation with L. punctata may be observed in NAP and MC-LR co-concomitant waters. This study provides theoretical support for the application of duckweed in eutrophic waters containing organic chemical pollutants.

Rapid screening for Klinefelter syndrome with a simple high-resolution melting assay: a multicenter study.

Klinefelter syndrome (KS) is the set of symptoms that result from the presence of an extra X chromosome in males. Postnatal population-based KS screening will enable timely diagnosis of this common chromosomal disease, providing the opportunity for early intervention and therapy at the time point when they are most effective and may prevent later symptoms or complications. Therefore, through this study, we introduced a simple high-resolution melting (HRM) assay for KS screening and evaluated its clinical sensitivity and specificity in three medical centers using 1373 clinical blood samples. The HRM assay utilized a single primer pair to simultaneously amplify specific regions in zinc finger protein, X-linked (ZFX) and zinc finger protein, Y-linked (ZFY). In cases of KS, the ratios of ZFX/ZFY are altered compared to those in normal males. As a result, the specific melting profiles differ and can be differentiated during data analysis. This HRM assay displayed high analytical specificity over a wide range of template DNA amounts (5 ng-50 ng) and reproducibility, high resolution for detecting KS mosaicism, and high clinical sensitivity (100%) and specificity (98.1%). Moreover, the HRM assay was rapid (2 h per run), inexpensive (0.2 USD per sample), easy to perform and automatic, and compatible with both whole blood samples and dried blood spots. Therefore, this HRM assay is an ideal postnatal population-based KS screening tool that can be used for different age groups.

[Conventional and molecular cytogenetic analyses of a derivative X chromosome in amniocentesis].

OBJECTIVE: To analyze the aberrant der(X) chromosome using conventional and molecular cytogenetic approaches in a fetus of second trimester and to discuss its clinical effect. METHODS: Conventional cytogenetic procedures (GTG and CBG banding) were performed on cultured amniotic fluid cells. Three-color fluorescence in situ hybridization (FISH) consisting of X chromosome enumeration probes(CEPX), CEPY and Tel Xp/Yp was further performed to study the aberrant der(X) chromosome. RESULTS: Der(X) was a rare X/Y translocation. The final karyotypes of the fetus was designated as: 46,X,der(X)t(X;Y)(p22.3;q11.2). ish der(X)t(X;Y)(p22.3;q11.2)(X/Ypter-, DXZ1+, DYZ1+)mat. CONCLUSION: The combination of FISH and conventional cytogenetic techniques is a powerful tool to determine derivative chromosome and to offer an accurate genetic counseling. Identification of Xp; Yq rearrangement can help estimate the risk of fetus abnormalities and give a more precise prognosis.

N-[4-(ß-d-Allopyranos-yloxy)benzyl-idene]methyl-amine.

The title compound, C(14)H(19)NO(6), was synthesized by the condensation reaction between hecilid (4-formyl-phenl-ß-d-allopyran-oside) and methyl-amine in methanol. In the crystal structure, the pyran ring adopts a chair conformation and adjacent mol-ecules are linked by inter-molecular O-H⋯O and O-H⋯N hydrogen bonds, forming a three-dimensional network.