Joint toxicity of cadmium (II) and microplastic leachates on wheat seed germination and seedling growth.

Cadmium (Cd) pollution ranks first in soils (7.0%) and microplastics usually have a significant adsorption capacity for it, which could pose potential threats to agricultural production and human health. However, the joint toxicity of Cd and microplastics on crop growth remains largely unknown. In this study, the toxic effects of Cd2+ and two kinds of microplastic leachates, polyvinyl chloride (PVC) and low-density polyethylene (LDPE), on wheat seed germination and seedlings' growth were explored under single and combined conditions. The results showed that Cd2+ solution and two kinds of microplastic leachates stimulated the wheat seed germination process but inhibited the germination rate by 0-8.6%. The combined treatments promoted wheat seed germination but inhibited the seedlings' growth to different degrees. Specifically, the combination of 2.0 mg L-1 Cd2+ and 1.0 mgC L-1 PVC promoted both seed germination and seedlings' growth, but they synergistically increased the antioxidant enzyme activity of seedlings. The toxicity of the PVC leachate to wheat seedlings was stronger than LDPE leachate. The addition of Cd2+ could alleviate the toxicity of PVC leachate on seedlings, and reduce the toxicity of LDPE leachate on seedlings under the same concentration class combinations but aggravated stress under different concentration classes, consistent with the effect on seedlings' growth. Overall, Cd2+, PVC, and LDPE leachates have toxic effects on wheat growth, whether treated under single or combined treatments. This study has important implications for the joint toxicity of Cd2+ solution and microplastic leachates in agriculture.

Biofilm-developed biomass residues as novel bulking agents and microbial carriers for synergistically enhanced bioevaporation: Degradation potential and contribution to metabolic heat.

Economical and easily prepared bulking agents and microbial carriers are essential in the practical application of bioevaporation process. Biofilm-developed biomass residues not only provide structural support and microbial sources but also may contribute metabolic heat to the bioevaporation process, achieving the enhanced water evaporation and synergistic treatment of biomass residues. In this study, biofilm was cultivated on the rice straw, wheat straw, sawdust, corncob, luffa cylindrica and palm first, then those biofilm-developed biomass residues were successfully used as the bulking agents and microbial carriers in food waste bioevaporation. The degradation potential (volatile solid degradation ratio) of those biomass residues was in the order of corncob (23.96%), wheat straw (21.12%), rice straw (14.57%), luffa cylindrica (11.02%), sawdust (-2.87%) and palm (-9.24%). It's primarily the degradation of the major components, cellulose and hemicellulose, in corncob and wheat straw governed the metabolic heat contribution (91.73 and 79.61%) to the bioevaporation process. While the high lignin content in sawdust (14.57%) and palm (28.62%) caused negligible degradation of cellulose and hemicellulose, hence made them only function as structural supporter and did not contribute any metabolic heat. Moreover, though the metabolic heat contribution of rice straw and luffa cylindrica reached 58.19 and 37.84%, their lowest lignocellulose content (62.99 and 65.95%) and their lower density, as well as the dominated Xanthomonas (bacteria) and Mycothermus (fungi) led to their rapid collapse during the repeated cycles of bioevaporation. The greatest abundance of thermophilic bacteria (22.3-88.0%) and thermophilic fungi (82.0-99.3%) was observed in the corncob pile. Furthermore, considering the Staphylococcus (pathogenic bacteria) and Candida (animal pathogen) was effectively inhibited, the biofilm-developed corncob was the most favorable bulking agents and microbial carrier for the synergistic bioevaporation of highly concentrated organic wastewater and biomass residues.

Anisotropic Cell Expansion Is Affected through the Bidirectional Mobility of Cellulose Synthase Complexes and Phosphorylation at Two Critical Residues on CESA3.

Here we report that phosphorylation status of S211 and T212 of the CESA3 component of Arabidopsis (Arabidopsis thaliana) cellulose synthase impacts the regulation of anisotropic cell expansion as well as cellulose synthesis and deposition and microtubule-dependent bidirectional mobility of CESA complexes. Mutation of S211 to Ala caused a significant decrease in the length of etiolated hypocotyls and primary roots, while root hairs were not significantly affected. By contrast, the S211E mutation stunted the growth of root hairs, but primary roots were not significantly affected. Similarly, T212E caused a decrease in the length of root hairs but not root length. However, T212E stunted the growth of etiolated hypocotyls. Live-cell imaging of fluorescently labeled CESA showed that the rate of movement of CESA particles was directionally asymmetric in etiolated hypocotyls of S211A and T212E mutants, while similar bidirectional velocities were observed with the wild-type control and S211E and T212A mutant lines. Analysis of cell wall composition and the innermost layer of cell wall suggests a role for phosphorylation of CESA3 S211 and T212 in cellulose aggregation into fibrillar bundles. These results suggest that microtubule-guided bidirectional mobility of CESA complexes is fine-tuned by phosphorylation of CESA3 S211 and T212, which may, in turn, modulate cellulose synthesis and organization, resulting in or contributing to the observed defects of anisotropic cell expansion.

Fertilization regime shifts the molecular diversity and chlorine reactivity of soil dissolved organic matter from tropical croplands.

Soil-derived dissolved organic matter (SDOM) is an important site-specific disinfection byproduct (DBP) precursor in watersheds. However, it remains unclear how fertilization regime shifts the molecular diversity and chlorine reactivity of SDOM in cropland-impacted watersheds. Here, we analyzed the spectroscopic and molecular-level characteristics of the SDOM from croplands that had different fertilization regimes (i.e., non-fertilization, chemical fertilization, straw return, and chemical fertilization plus straw return) for 5 years and evaluated the chlorine reactivity of the SDOM by determining the 24-h chlorine consumption and specific DBP formation potential (SDBP-FP). The SDOM level decreased by chemical fertilization and was not significantly altered by straw return alone or combined with chemical fertilizer. However, all fertilization regimes elevated the molecular diversity of SDOM by increasing the abundance of protein-, lignin-, and tannin-like compounds. The chlorine reactivity of SDOM was reduced by chemical fertilization, but was significantly increased by straw return. Typically, straw return increased the formation potential of specific trihalomethane and chloral hydrate by 339% and 56% via increasing the aromatics in SDOM, whereas chemical fertilization could effectively decrease about 231% of the increased specific trihalomethane formation potential caused by straw return. This study highlights that fertilization regime can significantly shape the molecular diversity and chlorine reactivity of the SDOM in croplands and that partially replacing chemical fertilizer with crop straw is an advantageous practice for reducing DBP risks in drinking water in cropland-impacted watersheds.

The effect of microplastics on behaviors of chiral imidazolinone herbicides in the aquatic environment: Residue, degradation and distribution.

The pollution of aquatic environments by microplastics and herbicides has become a global concern. This study was focused on imazamox, imazapic, and imazethapyr sorption to polypropylene microplastics in water. And the potential effects of microplastics on herbicide enantiomer degradation and distributions in water, sediment, and water-sediment microcosms were investigated. Adsorption experiment results indicated that herbicide sorption to microplastics involved both chemisorption and physical adsorption. Degradation experiment results indicated that microplastics could markedly increase herbicide persistence in water and sediment. Marked stereoselective degradation was not found for the three herbicides in water and sediment, but stereoselective degradation of imazapic in water containing microplastics was found. The water-sediment microcosms experiment results indicated that microplastics have significant effect on stereoselectivity degradation and distribution in water and water-sediment microcosms for imazapic, and have little effect on stereoselectivity behaviors of imazamox and imazethapyr in water-sediment systems. Furthermore, the microcosm experiment results also indicated that herbicides can partition between water and microplastics and that microplastics could affect herbicide persistence and distributions in aquatic environments. The present study provides new insights into the fate of chiral pollutants in aquatic environments containing microplastics, and contributes to understanding behaviors of herbicides and microplastics in aquatic environments.

Variations existing in protein-coding genes of the complete mitochondrial genomes of two highly morphological similarity fish: Periophthalmus magnuspinnatus and P. modestus (Perciformes, Gobiidae).

Periophthalmus magnuspinnatus is a new record species of Gobiidae in China. It had been misidentified as P. modestus for long time early before 2006. Here, the complete mitochondrial genome (mtDNA) sequences of the two species were first reported and analyzed comparably. The two genomes were both consisted of 13 protein-coding genes, 22 tRNA genes, two rRNA genes and a control region. Except for eight tRNA and ND6 genes, all other mitochondrial genes were encoded on the heavy strand. It was 16,496 bp and 16,803 bp, respectively, and P. modestus had a 238 bp-gap between tRNAleu and ND5. There were high variations (10-19%) in the protein-coding genes. In the initiation condon and stop codons, the two fish also had tiny difference. Phylogenetic analysis showed that P. magnuspinnatus and P. modestus first clustered together and then they constituted Gobiidae clade with other 12 fish. Whereas Odontobutidae and Rhyacichthyidae formed the sister group, then clustered with Eleotridae, and finally joined with Gobiidae, which is consist with previous phenotypic report. The study will contribute to the phylogenetic analysis of the Gobiidae and natural resources conservation of P. magnuspinnatus and P. modestus.

The association between health system development and the burden of cardiovascular disease: an analysis of WHO country profiles.

BACKGROUND: Several risk factors for cardiovascular disease (CVD) have been identified in recent decades. However, the association between the health system and the burden of CVD has not yet been sufficiently researched. The objective of this study was to analyse the association between health system development and the burden of CVD, in particular CVD-related disability-adjusted life-years (DALYs). METHODS: Univariate and multivariate generalized linear mixed models were applied to country-level data collected by the World Bank and World Health Organization. Response variables were the age-standardized CVD mortality and age-standardized CVD DALY rates. RESULTS: The amount of available health system resources, indicated by total health expenditures per capita, physician density, nurse density, dentistry density, pharmaceutical density and the density of hospital beds, was associated with reduced CVD DALY rates and CVD mortality. However, in the multivariate models, the density of nurses and midwives was positively associated with CVD. High out-of-pocket costs were associated with increased CVD mortality in both univariate and multivariate analyses. CONCLUSION: A highly developed health system with a low level of out-of-pocket costs seems to be the most appropriate to reduce the burden of CVD. Furthermore, an efficient balance between human health resources and health technologies is essential.