Characterization of a novel micro-pressure double-cycle reactor for low temperature municipal wastewater treatment.

To solve the deterioration of effluent caused by low temperature in urban sewage treatment plant in cold areas, a new type of reactor was proposed, the biochemical environmental and low-temperature operating characteristics of the reactor were studied. Through analysis of flow simulation and dissolved oxygen (DO) distribution when the aeration rate was 0.6 m3/h, it showed that there were many different DO environments in the reactor at the same time, which provided favourable conditions for various biochemical reactions. The operation test showed that the average effluent removal rate of COD, TN, NH4+-N and TP was 92.53%, 74.57%, 89.61% and 96.04%, respectively. And there were a variety of functional bacteria related to nitrogen and phosphorus removal in the system, most of them with strong adaptability at low temperatures. Among the dominant microorganisms, Flavobacterium and Rhodobacter were related to denitrification, Aeromonas and Thiothrix were related to phosphorous removal. Denitrifying phosphorus removal was the main way of phosphorus removal. Picrust2 results showed that the reactor operated well at low temperature, and the regional difference distribution of nitrification genes further confirmed the existence of functional zones in the reactor. The results showed that the Micro-pressure Double-cycle reactor worked well at low temperature, which provided a new idea and way for the upgrading of urban sewage treatment plants in cold areas.

Study on the inhibition of sludge bulking in A2/O coupled system at low temperature by segmented inlet water mode.

This study aimed to propose a segmented influent method to inhibit sludge bulking. The sludge bulking phenomenon was observed in a A2/O coupled system treating municipal wastewater under low temperature (15 ± 0.5)°C. Adopting the segmented inlet water process, the distribution ratio of the inlet flow in the anaerobic zone and the aerobic zone were 2:1 and 1:1, the sludge bulking phenomenon was suppressed. The sludge loading rate (F/M) analysis showed that the F/M of the anaerobic zone with single-point inflow was only 0.15 kg COD·(kg MLSS·d)-1, which was prone to induce sludge bulking. However, the F/M concentration gradient of the system under segmented inlet water conditions was obvious, which could inhibit the sludge bulking caused by low F/M. The effluent removal results showed that the system had high removal rates of COD, NH4+-N, TN, and TP at a flow distribution ratio of 2:1, with average removal rates of 88.85% ± 2.94%, 91.26% ± 6.68%, 76.60% ± 5.60%, and 96.80% ± 2.17%, respectively. This study confirmed that the segment inlet method inhibited sludge bulking, while the flow distribution ratio of 2:1 also ensured efficient pollutant removal capacity of the system.

Simultaneous removal of organic matter and nitrogen by heterotrophic nitrification-aerobic denitrification bacteria in an air-lift multi-stage circulating integrated bioreactor.

This study aimed to propose a novel air-lift multi-stage circulating integrated bioreactor (AMCIB) to treat urban sewage. The AMCIB combined the reaction zone and sedimentation zone, the alternating circulation of activated sludge in separate aerobic and anaerobic environments facilitates the enrichment of HN-AD bacteria. The preliminary study showed that AMCIB had high removal efficiencies for COD, NH4+-N, TN and TP under high dissolved oxygen (DO) concentration conditions, with average removal rates of 93.21 %, 96.04 %, 75.06 % and 94.30 %, respectively. IlluminaMiSeq sequencing results showed that the system successfully cultured heterotrophic nitrification-aerobic denitrification (HN-AD) functional bacteria (Pseudomonas, Acinetobacter, Aeromonas) that played a crucial role in sewage treatment, and Tetrasphaera was the central phosphorus removing bacteria in the system. Functional gene predictions showed that the HN-AD played a dominant role in the system.

Full-Length Transcriptome Sequencing Reveals Tissue-Specific Gene Expression Profile of Mangrove Clam Geloina erosa.

Mollusca is the second largest animal phylum and represents one of the most evolutionarily successful animal groups. Geloina erosa, a species of Corbiculidae, plays an important role in mangrove ecology. It is highly adaptable and can withstand environmental pollution and microbial infections. However, there is no reference genome or full-length transcriptome available for G. erosa. This impedes the study of the biological functions of its different tissues because transcriptome research requires reference genome or full-length transcriptome as a reference to improve accuracy. In this study, we applied a combination of Illumina and PacBio single-molecule real-time sequencing technologies to sequence the full-length transcriptomes of G. erosa tissues. Transcriptomes of nine samples obtained from three tissues (hepatopancreas, gill, and muscle) were sequenced using Illumina. Furthermore, we obtained 87,310 full-length reads non-chimeric sequences. After removing redundancy, 22,749 transcripts were obtained. The average Q score of 30 was 94.48%. In total, 271 alternative splicing events were predicted. There were 14,496 complete regions and 3,870 lncRNAs. Differential expression analysis revealed tissue-specific physiological functions. The gills mainly express functions related to filtration, metabolism, identifying pathogens and activating immunity, and neural activity. The hepatopancreas is the main tissue related to metabolism, it also involved in the immune response. The muscle mainly express functions related to muscle movement and control, it contains more energy metabolites that gill and hepatopancreas. Our research provides an important reference for studying the gene expression of G. erosa under various environmental stresses. Moreover, we present a reliable sequence that will provide an excellent foundation for further research on G. erosa.

RhoGDI2 positively regulates the Rho GTPases activation in response to the ß2 outside-in signaling in T cells adhesion and migration on ICAM-1.

Cytoskeletal reorganization driven by Rho GTPases plays a crucial role in the migration of T cells, which are key regulators of immunity. The molecular mechanisms that control actin cytoskeleton remodeling during T cell movement have only partially been clarified as the function of many modulators has not been evaluated in these cells. Here, we report a new function of RhoGDI2 by showing that this protein positively regulates Rho GTPase activation during T cell adhesion and migration. RhoGDI2 knockdown significantly reduced T cell adhesion and migration. Furthermore, RhoGDI2 knockdown decreased the activation of Rac1 and Cdc42, 2 members of Rho GTPases, and the remodeling of the actin cytoskeleton. Upon P-selectin glycoprotein ligand-1 engagement, RhoGDI2 was phosphorylated at Y24 and Y153 by kinases related to ß2 integrin outside-in signaling, Src, c-Abl, and Syk, resulting in the accumulation of RhoGDI2 at the cell membrane. Subsequent phosphorylation of S31 induced the opening of RhoGDI2 and the release of Rho GTPases, whereas phosphorylation of Y153 might promote the activation of Rho GTPases by recruiting Vav1. Moreover, the disruption of lipid rafts with methyl-ß-cyclodextrin blocked the interaction between integrins and RhoGDI2, reducing the level of phosphorylated RhoGDI2 and the activation of downstream Rho GTPases. Based on these observations, RhoGDI2 is a target of intergrin outside-in signaling that activates Rho GTPases during T cell adhesion and migration, and RhoGDI2-mediated signal transduction is based on the lipid rafts integrity.

Complete mitochondrial genome and the phylogenetic position of the Sphaeroma sp. (Crustacea, Isopod, Sphaeromatidae).

The complete mitogenome of Sphaeroma sp. (Crustacea, Isopod, Sphaeromatidae) was determined in this study. The total length of mitogenome was 15,839 bp, and contained 13 protein-coding genes, 21 tRNA genes, 2 rRNA genes, 1 control region, and 2 unknown fragments which longer than 200 bp. The nucleotide composition was 25.80% A, 16.56% C, 25.94% G and 31.67% T. Six initiation codons (ATA, ATC, ATG, ATT, ACG, GTG) and three termination codons (TAA, TAG, TA-) were used in the protein-coding genes. The length of tRNA genes ranged from 52 to 65 bp, and tRNA-Arg was not identified. The phylogenetic result showed Sphaeroma sp. was closely related to Sphaeroma terebrans with high bootstrap value supported.

Lipid raft­associated ß­adducin participates in neutrophil migration.

Previous studies have demonstrated that lipid rafts and ß­adducin serve an important role in leukocyte rolling. In the present study the migratory ability and behavior of neutrophils was demonstrated to rely on the integrity of the lipid raft structure. ß­adducin was demonstrated to have a critical role in neutrophil migration. Knockdown of ß­adducin attenuated the migratory ability of dHL­60 cells and the distribution of ß­adducin in lipid raft structures was changed by N­formylmethionyl­leucyl­phenyl­alanine treatment. Furthermore, the findings demonstrated that the tyrosine phosphorylation of ß­adducin was required for its relocation. The results of the present study suggested that the lipid raft­associated protein ß­adducin may be a novel control point for the excessive infiltration of neutrophils during inflammation.

Complete mitochondrial genome of the Spadenose shark Scoliodon laticaudus (Carcharhiniformes: Carcharhinidae).

The complete mitochondrial genome of the Spadenose shark Scoliodon laticaudus has been determined for the first time in this study. It was 16,695 bp in length and consisted of 37 genes with typical gene order in vertebrate mitogenome. The nucleotide base content of S. laticaudus mitogenome was 31.5% A, 23.7% C, 13.2% G and 31.6% T. Two start codons (GTG and ATG) and three stop codons (AGA, TAG and TAA/T) were used in the protein-coding genes. The 22 tRNAs ranged from 67 bp (tRNA-Cys and tRNA-Ser2) to 75 bp (tRNA-Leu1) in length. The tRNA-Ser2 could not be folded into typical cloverleaf secondary structure by lacking the dihydrouridine (DHC) arm stem.

Complete mitochondrial genome of the Yellow-spotted skate Okamejei hollandi (Rajiformes: Rajidae).

The complete mitochondrial genome of the Yellow-spotted skate Okamejei hollandi was determined in this study. It is 16,974 bp in length and contains 13 protein-coding genes, two rRNA genes, 22 tRNA genes, and one putative control region. The overall base composition is 30.5% A, 27.8% C, 14.0% G, and 27.8% T. There are 28 bp short intergenic spaces located in 12 gene junctions and 31 bp overlaps located in nine gene junctions in the whole mitogenome. Two start codons (ATG and GTG) and two stop codons (TAG and TAA/T) were used in the protein-coding genes. The lengths of 22 tRNA genes range from 68 (tRNA-Ser2) to 75 (tRNA-Leu1) bp. The origin of L-strand replication (OL) sequence (37 bp) was identified between the tRNA-Asn and tRNA-Cys genes. The control region is 1311 bp in length with high A + T and poor G content.

Lipid raft-associated ß-adducin is required for PSGL-1-mediated neutrophil rolling on P-selectin.

Lipid rafts, a liquid-ordered plasma membrane microdomain, are related to cell-surface receptor function. PSGL-1, a major surface receptor protein for leukocyte, also acts as a signaling receptor in leukocyte rolling. To investigate the role of lipid raft in PSGL-1 signaling in human neutrophils, we quantitatively analyzed lipid raft proteome of human promyelocytic leukemia cell line HL-60 cells and identified a lipid raft-associated protein ß-adducin. PSGL-1 ligation induced dissociation of the raft-associated protein ß-adducin from lipid rafts and actin, as well as phosphorylation of ß-adducin, indicating a transient uncoupling of lipid rafts from the actin cytoskeleton. Knockdown of ß-adducin greatly attenuated HL-60 cells rolling on P-selectin. We also showed that Src kinase is crucial for PSGL-1 ligation-induced ß-adducin phosphorylation and relocation. Taken together, these results show that ß-adducin is a pivotal lipid raft-associated protein in PSGL-1-mediated neutrophil rolling on P-selectin.

PI3K is involved in ß1 integrin clustering by PSGL-1 and promotes ß1 integrin-mediated Jurkat cell adhesion to fibronectin.

P-selectin glycoprotein ligand-1 (PSGL-1) is involved in the initial step of lymphocyte homing by interacting with P- or E-selectins expressed on activated endothelium cells. Besides, it also functions as a receptor to induce signals that increase integrin affinity to ligands and mediate cell adhesion to endothelium. Integrin is required for the second step of lymphocyte homing, whose activation has been reported tightly regulated by inside-out signals triggered by chemokines or the shear-stress generated during lymphocyte rolling on endothelium. However, the relationship between PSGL-1-triggered signals and integrin activation is not clear. In this study, we demonstrated that PSGL-1 ligation induces ß1 integrin-mediated adhesion to fibronectin via regulation of both ß1 subunit clustering and conformation changes. Phosphoinositide 3-kinase (PI3K) is required for PSGL-1-induced ß1 integrin clustering which ultimately regulates ß1 integrin-mediated Jurkat cell adhesion to fibronectin. However, PI3K is not involved in the conformation changes or increases in the total expression of ß1 integrin. Taken together, we found a novel signal pathway, PSGL-1-PI3K-ß1 integrin, demonstrating the cooperation between initial adhesion and subsequent arrest and stable adhesion.

Lipid Raft is required for PSGL-1 ligation induced HL-60 cell adhesion on ICAM-1.

P-selectin glycoprotein ligand-1 (PSGL-1) and integrins are adhesion molecules that play critical roles in host defense and innate immunity. PSGL-1 mediates leukocyte rolling and primes leukocytes for integrin-mediated adhesion. However, the mechanism that PSGL-1 as a rolling receptor in regulating integrin activation has not been well characterized. Here, we investigate the function of lipid raft in regulating PSGL-1 induced ß2 integrin-mediated HL-60 cells adhesion. PSGL-1 ligation with antibody enhances the ß2 integrin activation and ß2 integrin-dependent adhesion to ICAM-1. Importantly, with the treatment of methyl-ß-cyclodextrin (MßCD), we confirm the role of lipid raft in regulating the activation of ß2 integrin. Furthermore, we find that the protein level of PSGL-1 decreased in raft fractions in MßCD treated cells. PSGL-1 ligation induces the recruitment of spleen tyrosine kinase (Syk), a tyrosine kinase and Vav1 (the pivotal downstream effector of Syk signaling pathway involved in cytoskeleton regulation) to lipid raft. Inhibition of Syk activity with pharmacologic inhibitor strongly reduces HL-60 cells adhesion, implicating Syk is crucial for PSGL-1 mediated ß2 integrin activation. Taken together, we report that ligation of PSGL-1 on HL-60 cells activates ß2 integrin, for which lipid raft integrity and Syk activation are responsible. These findings have shed new light on the mechanisms that connect leukocyte initial rolling with subsequent adhesion.