Mitigating sediment cadmium contamination through combining PGPR Enterobacter ludwigii with the submerged macrophyte Vallisneria natans.

Sediment cadmium contamination poses risks to aquatic ecosystems. Phytoremediation is an environmentally sustainable method to mitigate cadmium contamination. Submerged macrophytes are affected by cadmium stress, but plant growth-promoting rhizobacteria (PGPR) can restore the health status of submerged macrophytes. Herein, we aimed to reduce sediment cadmium concentration and reveal the mechanism by which the combined application of the PGPR Enterobacter ludwigii and the submerged macrophyte Vallisneria natans mitigates cadmium contamination. Sediment cadmium concentration decreased by 21.59% after submerged macrophytes were planted with PGPR, probably because the PGPR colonized the rhizosphere and roots of the macrophytes. The PGPR induced a 5.09-fold increase in submerged macrophyte biomass and enhanced plant antioxidant response to cadmium stress, as demonstrated by decreases in oxidative product levels (reactive oxygen species and malondialdehyde), which corresponded to shift in rhizosphere metabolism, notably in antioxidant defence systems (i.e., the peroxidation of linoleic acid into 9-hydroperoxy-10E,12Z-octadecadienoic acid) and in some amino acid metabolism pathways (i.e., arginine and proline). Additionally, PGPR mineralized carbon in the sediment to promote submerged macrophyte growth. Overall, PGPR mitigated sediment cadmium accumulation via a synergistic plantmicrobe mechanism. This work revealed the mechanism by which PGPR and submerged macrophytes control cadmium concentration in contaminated sediment.

Submerged macrophyte restoration enhanced microbial carbon utilization in shallow lakes.

Submerged macrophytes are integral to the functioning of shallow lakes through their interaction with microorganisms. However, we have a limited understanding of how microbial communities in shallow lakes respond when macrophytes are restored after being historically extirpated. Here, we explored the interactions between prokaryotic communities and carbon utilization in two lakes where submerged macrophytes were restored. We found restoration reduced total carbon in sediment by 8.9 %-27.9 % and total organic carbon by 16.7 %-36.9 % relative to control treatment, but had no effects on carbon content in the overlying water. Sediment microbial communities were more sensitive to restoration than planktonic microbes and showed enhanced utilization of simple carbon substrates, such as Tween 40, after restoration. The increase in carbon utilization was attributed to declines in the relative abundance of some genera, such as Saccharicenans and Desertimonas, which were found weakly associated with the utilization of different carbon substrates. These genera likely competed with microbes with high carbon utilization in restored areas, such as Lubomirskia. Our findings highlight how restoring submerged macrophytes can enhance microbial carbon utilization and provide guidance to improve the carbon sequestration capacity of restored shallow lakes.

Temperature-mediated microbial carbon utilization in China's lakes.

Microbes play an important role in aquatic carbon cycling but we have a limited understanding of their functional responses to changes in temperature across large geographic areas. Here, we explored how microbial communities utilized different carbon substrates and the underlying ecological mechanisms along a space-for-time substitution temperature gradient of future climate change. The gradient included 47 lakes from five major lake regions in China spanning a difference of nearly 15°C in mean annual temperatures (MAT). Our results indicated that lakes from warmer regions generally had lower values of variables related to carbon concentrations and greater carbon utilization than those from colder regions. The greater utilization of carbon substrates under higher temperatures could be attributed to changes in bacterial community composition, with a greater abundance of Cyanobacteria and Actinobacteriota and less Proteobacteria in warmer lake regions. We also found that the core species in microbial networks changed with increasing temperature, from Hydrogenophaga and Rhodobacteraceae, which inhibited the utilization of amino acids and carbohydrates, to the CL500-29-marine-group, which promoted the utilization of all almost carbon substrates. Overall, our findings suggest that temperature can mediate aquatic carbon utilization by changing the interactions between bacteria and individual carbon substrates, and the discovery of core species that affect carbon utilization provides insight into potential carbon sequestration within inland water bodies under future climate warming.

Self-Assembled L-DNA Linkers for Rapid Construction of Multi-Specific Antibody-Drug Conjugates Library.

One of the key challenges of improving clinical outcomes of antibody drug conjugates (ADCs) is overcoming cancer resistance to the antibody and/or drug components of ADCs, and hence the need for ADC platforms with high combinatory flexibility. Here, we introduce the use of self-assembled left-handed DNA (L-DNA) oligonucleotides to link combinatory single-domain antibodies and toxin payloads for tunable and adaptive delivery of ADCs. We demonstrate that the method allows convenient construction of a library of ADCs with multi-specific targeting, multi-specific payloads, and exact drug-antibody ratio. The newly constructed ADCs with L-DNA scaffold showed favorable properties of in vitro cell cytotoxicity and in vivo suppression and eradication of solid tumors. Collectively, our data suggest that the L-DNA based modular ADC (MADC) platform is a viable option for generating therapeutic ADCs and for potentially expanding ADC therapeutic window via multi-specificity.

Structural evolution of China's intersectoral embodied carbon emission flow network.

Mount of embodied carbon emissions flow along industrial chains and form a complex network. In order to reveal the structure and evolution characteristics of embodied carbon emission flow network among China's industrial sectors, this study applies a complex network theory to construct six embodied carbon emission flow networks with 30 sectors on the basis of China's input-output tables from 2002 to 2015. Through the analysis of complex network technology indicators, the overall structural characteristics of the network, the key sectors, and the key flow paths are analyzed. Main results show that six embodied carbon emission flow networks all have the small-world characteristics; there is an industrial cluster phenomenon in the network. During the study period, construction, manufacturing, and service-related industry community are the absorption sites for embodied carbon emissions. Coal- and petroleum-related industry communities are the divergent sites for embodied carbon emissions; moreover, electric and heat power and fuel processing are the important "suppliers" of embodied carbon emissions; construction and other service are the important "consumers" of embodied carbon emissions. Non-metallic products are the important "transmitters" of embodied carbon emissions. Metal smelting and chemical industry are at the core of the network because of their high weighted degree and betweenness centrality. The central effect of key sectors continues to increase over time; furthermore, the distribution of embodied carbon emission flows in the six networks all have long-tail characteristics, and this characteristic became more prominent over time. There are key edge-weights in the networks. About 11 to 15% of the edges carry 80% of the embodied carbon emissions. Further based on edge-weight analysis, this study identifies the key paths of embodied carbon emission flow in the six networks, and most key paths pass through construction. Thus, such key sectors and key flow paths should receive more attention when making carbon emission reduction policies.

Complete mitochondrial genome and the phylogenetic position of the graceful catshark Proscyllium habereri (Carcharhiniformes: Proscylliidae).

In this study, the complete mitogenome of Proscyllium habereri (Carcharhiniformes: Proscylliidae) is first determined. It is 16,708 bp in length, containing 37 genes with typical order to that of most other vertebrates. Its overall base composition of the H-strand is A 30.9%; C 23.7%; G 14.2%; T 31.2%. Two start codons (ATG and GTG) and two stop codons (TAG and TAA/T) are found in the protein-coding genes. The 22 tRNA genes range from 67 bp (tRNA-Cys, tRNA-Ser2) to 75 bp (tRNA-Leu1). The phylogenetic result showed that P. habereri was clustered to Pseudotriakis microdon.

Complete mitochondrial genome and the phylogenetic position of the snaggletooth shark Hemipristis elongata (Carcharhiniformes: Hemigaleidae).

In this study, we first present the complete mitochondrial genome of Hemipristis elongata, the only member of genus Hemipristis in family Hemigaleidae. It is 16,691 bp in length with the typical gene order invertebrates. Its overall base composition is 31.7% A, 24.1% C, 12.9% G and 31.3% T. Two start codons (ATG and GTG) and three stop codons (TAG, AGA and TAA/T) are found in the protein-coding genes. The 22 tRNA genes ranged from 67 bp (tRNA-Cys, tRNA-Ser2) to 75 bp (tRNA-Leu1). The phylogenetic result showed that H. elongata was clustered to Hemigaleus microstoma and formed Hemigaleidae.

Complete mitochondrial genome and the phylogenetic position of the Jenkins whipray Himantura jenkinsii (Myliobatiformes, Dasyatidae).

We determined the complete mitochondrial genome of the Jenkins whipray Himantura jenkinsii. The total length of the mitogenome was 17, 670 bp, consisted of 37 genes with typical gene order in vertebrate mitogenome. The nucleotide composition was: 30.5% A, 29.1% T, 26.5% C and 13.9% G. It had 70 bp short intergenic spaces and 22 bp overlaps. Two start codons (GTG and ATG) and two stop codons (TAG and TAA/T) were used in the protein-coding genes. The 22 tRNA genes were ranged from 67 bp (tRNA-Ser2) to 75 bp (tRNA-Leu1). The phylogenetic result showed that H. jenkinsii was clustered with the Hortle's whipray H. hortlei.

Complete mitochondrial genome of the tiger shark Galeocerdo cuvier (Carcharhiniformes: Carcharhinidae).

The tiger shark Galeocerdo cuvier is the only member of the genus Galeocerdo. The complete mitochondrial genome of G. cuvier is presented for the first time in this study. The gene composition and arrangement in the mitogenome of G. cuvier is identical to most animal mitogenome. There are 22 bp short noncoding sequences and 44 bp overlaps in the mitogenome. The overall base composition is 31.8% A, 23.9% C, 13.0% G and 31.3% T. The dihydrouridine arm of tRNA-Ser2 was replaced by a simple loop and the other tRNAs could be folded into the typical cloverleaf structure.

Complete mitochondrial genome of the blue-spotted stingray Neotrygon kuhlii (Myliobatiformes: Dasyatidae).

The blue-spotted stingray Neotrygon kuhlii is a small stingray distributed in the Indian and West Pacific Ocean. It was considered a species complex by morphological and molecular evidences. In this study, we firstly presented the complete mitochondrial genome of N. kuhlii. It is 18,039 bp in length, including 13 protein-coding genes, two ribosomal RNA genes, 22 transfer RNA genes and 1 control region, with the typical gene order in the mitogenomes of vertebrates. The total base composition is 31.9% A, 26.4% C, 13.1% G and 28.6% T, with an A + T bias of 60.5%. Alignment results demonstrated that the mitochondrial sequences of N. kuhlii in this study were highly similar to the 12S, 16S, COI and Cyt b sequences of the specimens collected from the Chinese seas in other studies.