The deep-sea chemosynthetic environment is one of the most extreme environments on the Earth, with low oxygen, high hydrostatic pressure and high levels of toxic substances. Species of the family ...Vesicomyidae are among the dominant chemosymbiotic bivalves found in this harsh habitat. Mitochondria play a vital role in oxygen usage and energy metabolism; thus, they may be under selection during the adaptive evolution of deep-sea vesicomyids. In this study, the mitochondrial genome (mitogenome) of the vesicomyid bivalve Calyptogena marissinica was sequenced with Illumina sequencing. The mitogenome of C. marissinica is 17,374 bp in length and contains 13 protein-coding genes, 2 ribosomal RNA genes (rrnS and rrnL) and 22 transfer RNA genes. All of these genes are encoded on the heavy strand. Some special elements, such as tandem repeat sequences, "G(A)nT" motifs and AT-rich sequences, were observed in the control region of the C. marissinica mitogenome, which is involved in the regulation of replication and transcription of the mitogenome and may be helpful in adjusting the mitochondrial energy metabolism of organisms to adapt to the deep-sea chemosynthetic environment. The gene arrangement of protein-coding genes was identical to that of other sequenced vesicomyids. Phylogenetic analyses clustered C. marissinica with previously reported vesicomyid bivalves with high support values. Positive selection analysis revealed evidence of adaptive change in the mitogenome of Vesicomyidae. Ten potentially important adaptive residues were identified, which were located in cox1, cox3, cob, nad2, nad4 and nad5. Overall, this study sheds light on the mitogenomic adaptation of vesicomyid bivalves that inhabit the deep-sea chemosynthetic environment.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Organic-inorganic hybrid perovskites are promising candidates for the next-generation solar cells. Many efforts have been made to study their structures in the search for a better mechanistic ...understanding to guide the materials optimization. Here, we investigate the structure instability of the single-crystalline CH
NH
PbI
(MAPbI
) film by using transmission electron microscopy. We find that MAPbI
is very sensitive to the electron beam illumination and rapidly decomposes into the hexagonal PbI
. We propose a decomposition pathway, initiated with the loss of iodine ions, resulting in eventual collapse of perovskite structure and its decomposition into PbI
. These findings impose important question on the interpretation of experimental data based on electron diffraction and highlight the need to circumvent material decomposition in future electron microscopy studies. The structural evolution during decomposition process also sheds light on the structure instability of organic-inorganic hybrid perovskites in solar cell applications.
Here, single-atom Cu dispersed on N-doped graphene (Cu-SA/NGO) with relatively high Cu loading of 5.8 wt% was prepared for boosting the degradation of contaminants. This is the highest value yet ...reported for dispersion of single metal atoms on graphene. Atomically dispersed CuN
4
moieties were confirmed by high-angle annular dark field-scanning transmission electron microscopy and X-ray absorption fine structure spectroscopy. The prepared Cu-SA/NGO shows remarkable activity and stability in the degradation of various organic contaminants at neutral pH. This excellent performance is mainly ascribed to the large number of active sites obtained from high single-atom-Cu loading. Density functional theory calculations confirmed that CuN
4
moieties serve as the active sites, with low energy barriers for hydroxyl radical (&z.rad;OH) generation. These supported single-atom catalysts (SACs) catalyze the heterogeneous Fenton reaction
via
proton-mediated H
2
O
2
-homolytic pathway. This work offers a new method for fabricating various SACs with high loading levels for catalytic oxidation reactions.
A single-atom Cu dispersed on N-doped graphene with ultrahigh Cu loading of 5.8 wt% was prepared for boosting the degradation of contaminants.
Petrolisthes lamarckii (Leach, 1821) and P. haswelli Miers, 1884 are a pair of sister species of porcelain crabs, both of which are common in the intertidal zone of southern China, typically found ...under rocks and in the crevices of coral reefs. However, the distribution, genetic relationship and diversity of the two species in China have not been rigorously studied. Meanwhile, P. lamarckii is considered as a complex of cryptic species due to their diverse morphological features. In this study, we identified 127 specimens of the P. lamarckii–P. haswelli complex (LH complex) and recognised a new species through morphological and molecular analysis. Furthermore, we constructed a time-calibrated phylogeny of the LH complex using three mitochondrial and two nuclear genes from all three species, finding that the divergence of the LH complex can be traced back to the Miocene epoch, and that the genetic diversity increased during the Mid-Pleistocene transition period. Glacial refugia formed during the Pleistocene climatic oscillations has been regarded as one of the contributing factors to the diversification of marine organisms in the north-western Pacific. Petrolisthes haswelli demonstrates a wide distribution along the southern coast of China, while other lineages display more restricted distributions. The research on the demographic history and gene flow of P. haswelli revealed that the Chinese coastal populations experienced an expansion event approximately 12.5 thousand years ago (Kya) and the asymmetrical gene flows were observed between the two sides of the Taiwan Strait and Qiongzhou Strait, respectively, which is likely influenced by the restriction of ocean currents.
In this study, we analyzed 45 surface sediment samples collected in the marginal seas of the Western North Pacific, including the South China Sea, the East China Sea, and the Philippine Sea, to ...investigate the radiolarian assemblages and their relationship with upper layer environmental conditions. Based on the results of Q-mode cluster analysis, the radiolarian assemblages can be divided into four clusters, corresponding to the North Equatorial Current assemblage, North Equatorial Current Bifurcation assemblage, Kuroshio–South China Sea assemblage, and Kuroshio–East China Sea assemblage. Winter sea surface temperature (SSTw), winter sea surface salinity (SSSw), and annual silicate concentration were the most significant environmental variables associated with the radiolarian assemblages, among which SSTw showed the highest correlation with the radiolarian fauna. The significant influences of SSTw and SSSw suggested that the seasonal change of the North Equatorial Current–Kuroshio Current system exerted a crucial effect on the abundance and distribution pattern of the radiolarian fauna.
•The radiolarian fauna from northwest Pacific can be divided into four regional subgroups.•Winter sea surface temperature, winter sea surface salinity, and annual silicate concentration are significantly important.•The North Equatorial Current–Kuroshio Current system exerts remarkable influence in the study area.
Two specimens of the genus Hippolyte were examined from the caridean collections of the Marine Biological Museum, Chinese Academy of Sciences. These specimens were captured in the South China Sea in ...1987. Detailed inspection revealed that their morphological features closely match the (re)descriptions of Hippolyte australiensis , especially in the presence of a long, distinct lateral carina on the rostrum, a dorsally unarmed rostral border, and four prominent terminal spines on the dactylus of the last three pereiopods. The discovery of Hippolyte australiensis in Chinese waters represents a significant expansion of its geographic distribution from the South Pacific to the North Pacific. Furthermore, an additional taxonomical report of H. australiensis is provided since its retrieval in 2001.
Despite the high biological and ecological diversity of the South China Sea, limited research has been conducted on the deep‐sea species diversity of caridean shrimps. Based on the collections from ...three scientific expeditions conducted in the South China Sea, 31 caridean species, belonging to nine families, were reported, including the identification of two species not previously documented in this region, namely Janicella spinicauda (A. Milne‐Edwards, 1883) and Systellaspis curvispina Crosnier, 1988. In addition to morphological features, the COI and 16S gene sequences of these species were analyzed to assess their evolutionary relationships within each family. Phylogenetic analyses, with highest species coverage to date, indicated that similarity in morphological characteristics does not always lead to closer phylogenetic relationships and some defining characteristics for specific taxa are not always synapomorphies but may be the result of convergent evolution. Our results establish reliable evolutionary relationships within specific taxa and highlight the necessity for further taxonomic revisions within these taxa.
The South China Sea is known for its rich biological and ecological diversity. We present the findings from three scientific expeditions conducted in the South China Sea, reporting a total of 31 caridean shrimp species belonging to nine families. The results challenge the conventional notion that morphological similarity indicates close phylogenetic relationships.
Changes in the types and contents of metabolites in plants can occur in response to environmental stress. In this study, pumpkin seeds were cultivated in a cadmium ion solution (cadmium sulfate) for ...7 days, and growth parameters, antioxidant enzyme activities, and metabolites in the root, stem, and leaf were analyzed. The results showed that cadmium accumulation characteristics were in the order of root > stem > leaf. Cadmium restrained root growth and promoted superoxide dismutase, peroxidase, catalase activities in the root, but inhibited their activities in the leaf. Cadmium did not change the total biomass of pumpkin seedlings. Orthogonal partial least squares (OPLS) analyses were conducted to detect the relationships between fresh weight and metabolites. These analyses revealed that maltose had significantly positive relationships with the fresh weight of the root, stem, and leaf. Cadmium influenced glyoxylate and dicarboxylate metabolism, aminoacyl-tRNA biosynthesis, sulfur metabolism, butanoate metabolism, alanine, aspartate and glutamate metabolism, glutathione metabolism, glycine, serine and threonine metabolism in the root; glycolysis/gluconeogenesis in the stem; and biosynthesis of unsaturated fatty acids, galactose metabolism, cutin, suberine and wax biosynthesis in the leaf. It is important that cadmium inhibited root growth by inhibiting carbohydrate transport from the leaf to the root and promoted leaf growth by the accumulation of carbohydrates in the leaf. Furthermore, cadmium also restrained amino acid metabolism in the root of pumpkin seedlings. These results provide new information about how pumpkin seedlings respond to cadmium stress.
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•Cadmium accumulation characteristics were in the order of root > stem > leaf.•Cadmium had no significant effect on total biomass of pumpkin seedlings.•Leaf growth was enhanced by Cd due to the accumulation of carbohydrates in the leaf.•Cadmium reduced root growth by inhibiting carbohydrate transport from leaf to root.•Amino acid metabolism was restrained by cadmium in the root of pumpkin seedlings.
Life satisfaction is closely related to the quality of life. Previous studies showed that left-behind children have low life satisfaction levels due to their separation from their parents. Therefore, ...it is significant to explore the risk factors and protective factors of left-behind children's life satisfaction to improve their life quality. Therefore, the purpose of this study was to determine the mediating roles of perceived social support and sense of security in the relationship between negative life events and life satisfaction among left-behind children.
A survey was conducted on 281 left-behind children in rural Shandong, China using negative life events, perceived social support, a sense of security, and life satisfaction scales.
Negative life events had a negative impact on life satisfaction (
= -0.34,
= 0.001). In addition, not only does social support mediate between negative life events and life satisfaction (
= -0.21,
= 0.001), but also in between, security (
= -0.05,
= 0.030). Moreover, social support and security act as a chain intermediary between negative life events and life satisfaction (
= -0.03,
= 0.010), with an indirect effect share of 4.76%.
Negative life events could directly or indirectly affect the life satisfaction of left-behind children through the chain-mediating effects of perceived social support or the sense of security alone. Perceived social support and the sense of security are two important targets for further improving the life satisfaction of LBC.
Barnacles are specialized marine organisms that differ from other crustaceans in possession of a calcareous shell, which is attached to submerged surfaces. Barnacles have a wide distribution, mostly ...in the intertidal zone and shallow waters, but a few species inhabit the deep-sea floor. It is of interest to investigate how such sessile crustaceans became adapted to extreme deep-sea environments. We sequenced the transcriptomes of a deep-sea barnacle, Glyptelasma gigas collected at a depth of 731 m from the northern area of the Zhongjiannan Basin, and a shallow-water coordinal relative, Octolasmis warwicki. The purpose of this study was to provide genetic resources for investigating adaptation mechanisms of deep-sea barnacles.
Totals of 62,470 and 51,585 unigenes were assembled for G. gigas and O. warwicki, respectively, and functional annotation of these unigenes was made using public databases. Comparison of the protein-coding genes between the deep- and shallow-water barnacles, and with those of four other shallow-water crustaceans, revealed 26 gene families that had experienced significant expansion in G. gigas. Functional annotation showed that these expanded genes were predominately related to DNA repair, signal transduction and carbohydrate metabolism. Base substitution analysis on the 11,611 single-copy orthologs between G. gigas and O. warwicki indicated that 25 of them were distinctly positive selected in the deep-sea barnacle, including genes related to transcription, DNA repair, ligand binding, ion channels and energy metabolism, potentially indicating their importance for survival of G. gigas in the deep-sea environment.
The barnacle G. gigas has adopted strategies of expansion of specific gene families and of positive selection of key genes to counteract the negative effects of high hydrostatic pressure, hypoxia, low temperature and food limitation on the deep-sea floor. These expanded gene families and genes under positive selection would tend to enhance the capacities of G. gigas for signal transduction, genetic information processing and energy metabolism, and facilitate networks for perceiving and responding physiologically to the environmental conditions in deep-sea habitats. In short, our results provide genomic evidence relating to deep-sea adaptation of G. gigas, which provide a basis for further biological studies of sessile crustaceans in the deep sea.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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