Ocean acidification alters the benthic biofilm communities in intertidal soft sediments

Microphytobenthos (MPB) and bacterial biofilms play crucial roles in primary and secondary production, nutrient cycling and invertebrate settlement in coastal ecosystems, yet little is known of the effects of ocean acidification (OA) on these communities in intertidal soft sediments. To fill in this gap, a 28-day CO2 enhancement experiment was conducted for the benthic biofilms in soft intertidal sediments (muds and sands) from Qingdao, China. This experiment included three CO2 treatments: 400 ppm CO2 (control), 700 ppm CO2 and 1000 ppm CO2 (IPCC predicted value in 2100), which were established in a three-level CO2 incubator that can adjust the CO2 concentration in the overlying air. The effects of OA on benthic biofilms were assessed in the following three aspects: MPB biomass, biofilm community structure and microbial biogeochemical cycling (e.g., C-cycle, N-cycle and S-cycle). This study found that the 700 ppm CO2 treatment did not significantly affect the benthic biofilms in intertidal soft sediments, but the 1000 ppm CO2 treatment significantly altered the biofilm community composition and potentially their role in microbial biogeochemical cyc\ling in sediments (especially in sandy sediments). For the bacterial community in biofilms, the 1000 ppm CO2 enhancement increased the relative abundance of Alteromonadales and Bacillales but decreased the relative abundance of Rhodobacterales and Flavobacteriales. For microbial biogeochemical cycling, the 1000 ppm CO2 treatment enhanced the potential of chemoheterotrophic activity, nitrate reduction and sulfur respiration in sediments, likely resulting in a more stressful environment (hypoxic and enriched H2S) for most benthic organisms. Even though incubations in this study were only 28 days long and thus couldn’t fully accommodate the range of longer-term adaptions, it still suggests that benthic biofilms in intertidal sandy sediments are likely to change significantly near the end of the century if anthropogenic CO2 emissions unmitigated, with profound implications on local ecosystems and biogeochemical cycling

An Empirical Analysis of Trust, Perceived Benefit, and Purchase Intention in C2C Electronic Commerce in China

With the popularity and development of the internet, China's consumer-to-consumer (C2C) electronic commerce (EC) system is favored by consumers. Therefore, understanding the relationship among consumers' trust, perceived benefits (PBs), and purchase intentions (PIs) is of great significance for studying this system. This article proposes the hypothesis of the interaction among the three and designs a questionnaire to explain the application of trust, PB, and PI in China's C2C EC system. The relationship between the sample structure and the variables is analyzed using reliability, validity, correlation, and regression analysis (RA). The experimental analysis results show that the questionnaire's reliability and validity values are higher than 0.8 and 0.75, respectively, indicating that the questionnaire design is qualified, and the data are valid. The rationality of the hypothesis proposed here is verified through correlation analysis and RA. This indicates a significant mutual influence relationship among trust, PB, and PI

Time trend analysis of thyroid cancer surgery in China: single institutional database analysis of 15,000 patients

n/

Viral Diversity and Its Relationship With Environmental Factors at the Surface and Deep Sea of Prydz Bay, Antarctica

A viral metagenomic analysis of five surface and two bottom water (878 meters below surface, mbs, and 3,357 mbs) samples from Prydz Bay, was conducted during February–March 2015. The results demonstrated that most of the DNA viruses were dsDNA viruses (79.73–94.06%, except at PBI1, 37.51%). Of these, Caudovirales (Siphoviridae, Myoviridae, and Podoviridae) phages were most abundant in surface seawater (67.67–71.99%), while nucleocytoplasmic large DNA viruses (NCLDVs) (Phycodnaviridae, Mimiviridae, and Pandoraviridae accounted for >30% of dsDNA viruses) were most abundant in the bottom water (3,357 mbs). Of the ssDNA viruses, Microviridae was the dominant family in PBI2, PBI3, PBOs, and PBI4b (57.09–87.55%), while Inoviridae (58.16%) was the dominant family in PBI1. Cellulophaga phages (phi38:1 and phi10:1) and Flavobacterium phage 11b, infecting the possible host strains affiliated with the family Flavobacteriaceae of the phylum Bacteroidetes, were abundant in surface water dsDNA viromes. The long contig (PBI2_1_C) from the viral metagenomes were most similar to the genome architectures of Cellulophaga phage phi10:1 and Flavobacterium phage 11b from the Arctic Ocean. Comparative analysis showed that the surface viral community of Prydz Bay could be clearly separated from other marine and freshwater environments. The deep sea viral community was similar to the deep sea viral metagenome at A Long-term Oligotrophic Habitat Assessment Station (ALOHA, at 22°45′N, 158°00′W). The multivariable analysis indicated that nutrients probably played an important role in shaping the local viral community structure. This study revealed the preliminary characteristics of the viral community in Prydz Bay, from both the surface and the deep sea. It provided evidence of the relationships between the virome and the environment in Prydz Bay and provided the first data from the deep sea viral community of the Southern Ocean

Effect of grazing types on community-weighted mean functional traits and ecosystem functions on Inner Mongolian steppe, China

The relationships between community-weighted mean (CWM) functional traits and ecosystem functions have been extensively studied. However, how CWM traits and ecosystem functions respond to grazing types and whether the relationships between CWM traits and ecosystem functions mediate the response of ecosystem functions to grazing types remains controversial. In the present study, we set up a seven-year grazing experiment with four grazing types: no grazing (NG), cattle grazing (CG), sheep grazing (SG), and mixed grazing by sheep and cattle (MG) on Inner Mongolia grassland. Nine functional traits of dominant species and five ecosystem functions under different grazing types were determined, and the relationships between CWM traits and ecosystem functions were analyzed. The results showed that the CWM height decreased after grazing, while the CWM nitrogen and phosphorus contents increased after CG. SG caused a greater decrease in aboveground biomass (AGB) and a greater increase in the net ecosystem CO2 exchange (NEE) of grassland ecosystems than did CG. This result may be partially because the CWM nutrient content and NEE were more negatively related after CG; and the increase in the CWM nitrogen and phosphorus contents suppressed NEE after CG. Therefore, to protect the sustainability of grassland ecosystem functions, SG should be reduced. Additionally, our work emphasizes that the relationships between plant functional traits and ecosystem functions may mediate the response of ecosystem functions to grazing types

Vibrio Cyclitrophicus Phage Encoding Gene Transfer Agent Fragment, Representing a Novel Viral Family

Vibrio is a prevalent bacterial genus in aquatic environments and exhibits diverse metabolic capabilities, playing a vital role in marine biogeochemical cycles. This study isolated a novel virus infecting Vibrio cyclitrophicus, vB_VviC_ZQ26, from coastal waters near Qingdao, China. The vB_VviC_ZQ26 comprises a linear double-stranded DNA genome with a length of 42,982 bp and a G + C content of 43.21 %, encoding 72 putative open reading frames (ORFs). Transmission electron microscope characterization indicates a siphoviral-morphology of vB_VviC_ZQ26. Nucleic-acids-wide analysis indicates a tetranucleotide frequency deviation for genomic segments encoding putative gene transfer agent protein (GTA) and coil-containing protein, implying divergent origins occurred in different parts of viral genomes. Phylogenetic and genome-content-based analysis suggest that vB_VviC_ZQ26 represents a novel vibriophage-specific family designated as Coheviridae. From the result of biogeographic analysis, Coheviridae is mainly colonized in the temperate and tropical epipelagic zones. This study describes a novel vibriophage infecting V. cyclitrophicus, shedding light on the evolutionary divergence of different parts of the viral genome and its ecological footprint in marine environments

Insight Into the Pico- and Nano-Phytoplankton Communities in the Deepest Biosphere, the Mariana Trench

As photoautotrophs, phytoplankton are generally present in the euphotic zone of the ocean, however, recently healthy phytoplankton cells were found to be also ubiquitous in the dark deep sea, i.e., at water depths between 2000 and 4000 m. The distributions of phytoplankton communities in much deeper waters, such as the hadal zone, are unclear. In this study, the vertical distribution of the pico- and nano-phytoplankton (PN) communities from the surface to 8320 m, including the epipelagic, mesopelagic, bathypelagic, and hadal zones, were investigated via both 18S and p23S rRNA gene analysis in the Challenger Deep of the Mariana Trench. The results showed that Dinoflagellata, Chrysophyceae, Haptophyta, Chlorophyta, Prochloraceae, Pseudanabaenaceae, Synechococcaceae, and Eustigmatophyceae, etc., were the predominant PN in the Mariana Trench. Redundancy analyses revealed that depth, followed by temperature, was the most important environmental factors correlated with vertical distribution of PN community. In the hadal zone, the PN community structure was considerably different from those in the shallower zones. Some PN communities, e.g., Eustigmatophyceae and Chrysophyceae, which have the heterotrophic characteristics, were sparse in shallower waters, while they were identified with high relative abundance (94.1% and 20.1%, respectively) at the depth of 8320 m. However, the dinoflagellates and Prochloraceae Prochlorococcus were detected throughout the entire water column. We proposed that vertical sinking, heterotrophic metabolism, and/or the transition to resting stage of phytoplankton might contribute to the presence of phytoplankton in the hadal zone. This study provided insight into the PN community in the Mariana Trench, implied the significance of phytoplankton in exporting organic matters from the euphotic to the hadal zone, and also hinted the possible existence of some undetermined energy metabolism (e.g., heterotrophy) of phytoplankton making themselves adapt and survive in the hadal environment

Characterization and genome analysis of Vibrio phage vB_VhaP_PG11, representing a new viral genus

Vibrio is a kind of common gram-negative bacteria, which is widely distributed in marine and estuarine environments. In the study, a novel marine phage vB_VhaP_PG11, infecting Vibrio hangzhouensis, was isolated from the offshore waters of Qingdao, China. vB_VhaP_PG11 is a double-stranded DNA phage. The whole genome proteomic tree shows that vB_VhaP_PG11 phage is related to two Vibrio phages, Vibrio phage 1.238.A._10N.261.52.F10 and Vibrio phage 1.245.O._10N.261.54.C7, but with low homology. Their amino acids identity with vB_VhaP_PG11 is 42.77 and 41.49% respectively. The prediction results of genome-blast distance phylogeny (GBDP) and the analysis gene-sharing network indicate that vB_VhaP_PG11 belongs to a new genus in Schitoviridae, named Qingschitovirus. The study of Vibrio phage vB_VhaP_PG11 provides basic information contributing to a better understanding of interactions between Vibrio phages and their hosts and helps analyze unknown viral sequences in the metagenomic database

Abundance and ecological footprint of Pseudoalteromonas phage vB_PhoS_XC in the Ulva prolifera green tide

Pseudoalteromonas is a ubiquitous and abundant genus of marine bacteria commonly associated with algae. In this study, a novel siphoviral-morphological bacteriophage, vB_PhoS_XC, was isolated from the coastal seawaters of Qingdao (China) during a bloom of the Ulva prolifera (U. prolifera) green tide. The morphology of this phage (icosahedron head 51 ± 1 nm in diameter; a tail length of 86 ± 1 nm) was characterized through transmission electron microscope. The biological properties of this virus showed a short latent period (45 minutes), a large burst size (241 virions per cell) and a relatively wide range of temperatures/pH level tolerance (-20°C to 45°C and pH 4 to pH 10, respectively). The vB_PhoS_XC has a 46,490-bp double-stranded DNA genome with a G+C content of 40.0%, and encodes 72 open reading frames (ORFs). Thirty-five of these ORFs were assigned into known functions based on BLAST-based algorithm against NR database of GenBank. In addition, eco-genomic analysis provides the evidence of vB_PhoS_XC accompanied by bloom of U. prolifera, and confirmed the high expression of two phosphatase-metabolism-related auxiliary metabolic genes (AMGs). This study provides new insights into the functional and ecological roles of the Pseudoalteromonas phage vB_PhoS_XC, shedding light on the virological study approach combined with traditional isolation and meta-omics data

Transcriptome analysis highlights the influence of temperature on hydrolase and traps in nematode-trapping fungi

Pine wilt disease caused by Bursaphelenchus xylophilus poses a serious threat to the economic and ecological value of forestry. Nematode trapping fungi trap and kill nematodes using specialized trapping devices, which are highly efficient and non-toxic to the environment, and are very promising for use as biological control agents. In this study, we isolated several nematode-trapping fungi from various regions and screened three for their high nematocidal efficiency. However, the effectiveness of these fungi as nematicides is notably influenced by temperature and exhibits different morphologies in response to temperature fluctuations, which are categorized as “NA,” “thin,” “dense,” and “sparse.” The trend of trap formation with temperature was consistent with the trend of nematocidal efficiency with temperature. Both of which initially increased and then decreased with increasing temperature. Among them, Arthrobotrys cladodes exhibited the highest level of nematocidal activity and trap formation among the tested species. Transcriptome data were collected from A. cladodes with various trap morphologies. Hydrolase activity was significantly enriched according to GO and KEGG enrichment analyses. Eight genes related to hydrolases were found to be consistent with the trend of trap morphology with temperature. Weighted gene co-expression analysis and the Cytoscape network revealed that these 8 genes are associated with either mitosis or autophagy. This suggests that they contribute to the formation of “dense” structures in nematode-trapping fungi. One of these genes is the serine protein hydrolase gene involved in autophagy. This study reveals a potentially critical role for hydrolases in trap formation and nematocidal efficiency. And presents a model where temperature affects trap formation and nematocidal efficiency by influencing the serine protease prb1 involved in the autophagy process