Risk coupling analysis under accident scenario evolution: A methodological construct and application.

Dynamic processes in various fields exhibit risk coupling phenomena, but existing risk analysis studies tend to ignore the risk coupling effects of dynamic scenarios. Considering the principles of digitization, objective quantification, and the full process that should be adopted in the risk coupling analysis, an integrated risk coupling analysis framework is proposed. Specifically, the weighted Eclat algorithm is used to mine the risk association rules, then the key risk factors are extracted by social network analysis, and the stochastic Petri net is used to complete the construction, simulation, and evolution of accident scenarios. This universal framework can analyze the risk phenomena of accident scenario evolution in a process-oriented manner and decouple risks based on key risk factors and disconnect the chain of the accident scenario evolution process. Finally, the proposed framework is applied to the coupled analysis of fire risk in Chinese urban communities to verify its feasibility and scientific validity.

Technical Acoustic Measurements Combined with Clinical Parameters for the Differential Diagnosis of Nonalcoholic Steatohepatitis.

Background and aim: Diagnosing nonalcoholic steatohepatitis (NASH) is challenging. This study intended to explore the diagnostic value of multiple technical acoustic measurements in the diagnosis of NASH, and to establish a diagnostic model combining technical acoustic measurements with clinical parameters to improve the diagnostic efficacy of NASH. Methods: We consecutively enrolled 75 patients with clinically suspected nonalcoholic fatty liver disease (NAFLD) who underwent percutaneous liver biopsy in our hospital from June 2020 to December 2021. All cases underwent multiple advanced acoustic measurements for liver such as shear wave dispersion (SWD), shear wave speed (SWS), attenuation imaging (ATI), normalized local variance (NLV), and liver-kidney intensity ratio (Ratio) examination before liver biopsies. A nomogram prediction model combining the technical acoustic measurements and clinical parameters was established and the model is proposed to improve the diagnostic performance of NASH. Results: A total of 75 cases were included in this study. The classification of pathological grade for NASH was as follows: normal liver, (n = 15, 20%), nonalcoholic fatty liver (NAFL), (n = 44, 58.7%), and NASH, (n = 16, 21.3%). There were statistically significant differences in SWS (p = 0.002), acoustic coefficient (AC) (p = 0.018), NLV (p = 0.033), age (p = 0.013) and fasting blood glucose (Glu) (p = 0.049) between NASH and non-NASH. A nomogram model which includes SWS, AC, NLV, age and Glu was built to predict NASH, and the calibration curves showed good calibrations in both training and validation sets. The AUCs of the combined nomogram model for the training set and validation set were 0.8597 and 0.7794, respectively. Conclusion: There were statistically significant differences in SWS, AC, NLV, age and Glu between NASH and non-NASH. A nomogram model which includes SWS, AC, NLV, age and Glu was built to predict NASH. The predictive model has a higher diagnostic performance than a single factor model in the diagnosis of NASH and has good clinical application prospects.

Representation, mining and analysis of unsafe behaviour based on pan-scene data.

To describe the safety rules of various industrial process data and explore the characteristics of unsafe behaviour, the association rules of unsafe behaviour based on pan-scene were proposed in this study. First, based on the scene data theory, unsafe behaviour was described by eight dimensions (time, location, behavioural individual, unsafe action, behavioural attribute, behavioural trace, professional category and risk level) to achieve scene data description and structural transformation. Second, the Apriori algorithm was used to explore the distribution rules of unsafe behaviour dimensions and the interaction between different dimensions from two perspectives: single-dimensional statistical analysis and multidimensional association rule mining. Finally, through SPSS Modeler software, an empirical analysis of pan-scene data for subway construction was conducted, and the association rules between type of work, construction stage, working time and unsafe action were identified. Some strong association rules were produced by the association analysis. For example, during the 13:00-17:00 of the excavation floor stage, the most frequent unsafe action of machine operators is the irregular binding of lifting objects. This result could explain why some unsafe actions are prone to occur in different construction stages and working times for workers of different types, which can be controlled and managed in a targeted manner, thus reducing the possibility of accidents.

Sonodynamic therapy suppresses matrix collagen degradation in vulnerable atherosclerotic plaque by modulating caspase 3 - PEDF/HIF-1α - MMP-2/MMP-9 signaling in macrophages.

BACKGROUND: The rupture of vulnerable atherosclerotic plaque is the main cause of acute ischemic vascular events, and is characterized by pathological degradation of matrix collagen in the fibrous cap. In a previous study, we reported that 5-aminolevulinic acid-mediated sonodynamic therapy suppressed collagen degradation in rabbit plaque. However, the underlying molecular mechanism has yet to be fully elucidated. METHODS: We applied sinoporphyrin sodium-mediated sonodynamic therapy (DVDMS-SDT) to balloon-denuded rabbit and apolipoprotein E-deficient (ApoE-/-) mouse models to observe collagen content in plaque. Cultured human THP-1 and mouse peritoneal macrophage-derived foam cells were used for in vitro mechanistic studies. RESULTS: We observed that DVDMS-SDT decreased plaque area and increased the percentages of collagen and smooth muscle cells and reduced the percentage of macrophages in rabbit and ApoE-/- mouse advanced plaques. In vitro, DVDMS-SDT modulated the caspase 3-pigment epithelium-derived factor/hypoxia-inducible factor-1α (PEDF/HIF-1α)-matrix metalloprotease-2/9 (MMP-2/MMP-9) signaling in macrophage foam cells. CONCLUSIONS: Our findings show that DVDMS-SDT effectively inhibits matrix collagen degradation in advanced atherosclerotic plaque by modulating caspase 3-PEDF/HIF-1α-MMP-2/MMP-9 signaling in macrophage foam cells and therefore represents a suitable and promising clinical regimen to stabilize vulnerable plaques.

Ultrasound improved immune adjuvant delivery to induce DC maturation and T cell activation.

Tumor immunotherapy has emerged as a promising approach to tumor treatment. Currently, immune adjuvant-based therapeutic modalities are rarely curative in solid tumors owing to challenges including the low permeability and extremely poor water solubility of these adjuvants, limiting their ability to effectively promote dendritic cell (DC) maturation. Herein, we employed ultrasound-mediated cavitation (UMC) to promote the delivery of Toll-like receptor agonist (R837)-loaded pH-responsive liposomes (PEOz-Lip@R837) to tumors. The tumor-associated antigens (TAAs) produced by UMC treatment exhibited vaccinal activity, particularly in the presence of immune adjuvants, together promoting the maturation of DC and inducing cytokine production. Importantly, UMC can down-regulate immune checkpoint molecules, like Cd274, Foxp3 and Ctla4, synergistically stimulating the activation and proliferation of T cells in the body to facilitate tumor treatment. This UMC-enhanced PEOz-Lip@R837 approach was able to induce a robust antitumor immune response capable of arresting primary and distant tumor growth, while also developing immunological memory, protecting against tumor rechallenge following initial tumor clearance. Overall, these results highlight a promising UMC- and pH-sensitive immune adjuvant delivery-based treatment for tumors with the potential for clinical application.

Sonodynamic Therapy Promotes Efferocytosis via CD47 Down-Regulation in Advanced Atherosclerotic Plaque.

Atherosclerotic cerebrocardiovascular disease is the major cause of acute ischemic diseases in humans. Impaired efferocytosis contributes to the progression of atherosclerosis. Pathological and apoptotic cells fail to undergo effective phagocytic clearance, leading to increased inflammation and necrotic core formation. Previously, we reported that 5-aminolevulinic acid-mediated sonodynamic therapy (SDT) promotes apoptotic cell efferocytosis via ATP release in atherosclerotic plaques. However, the exact signaling molecule involved in this process is still unknown. In the present study, sinoporphyrin sodium-mediated SDT (DVDMS-SDT) was applied to balloon-denuded rabbits in vivo to observe changes in the composition of atherosclerotic lesions. Cultured human THP-1-derived and mouse peritoneal macrophage-derived foam cells were used for in vitro mechanistic studies. Three days after DVDMS-SDT treatment, macrophage efferocytosis was significantly enhanced whereas local inflammation was attenuated in rabbit atherosclerotic lesions. At days 7 and 28, the histopathological analysis showed that DVDMS-SDT inhibited the progression of atherosclerosis, reduced the macrophage content, and increased the smooth muscle cell content in a time-dependent manner. Mechanistically, DVDMS-SDT activated mitochondria-caspase apoptosis in foam cells. Interestingly, activated by DVDMS-SDT, caspase-3 a key factor of apoptosis, reduced the expression of the anti-phagocytic molecule CD47 in foam cells. Of great importance, the promotion of macrophage efferocytosis by DVDMS-SDT can be eliminated by the overexpression of CD47. Overall, these results demonstrated that DVDMS-SDT effectively boosted efferocytosis via deactivation of CD47 expression, thereby reducing inflammation in advanced atherosclerotic plaques.

Ultrasound-Enhanced Reactive Oxygen Species Responsive Charge-Reversal Polymeric Nanocarriers for Efficient Pancreatic Cancer Gene Delivery.

Inefficient intracellular gene release and transfection limit nonviral gene delivery applications in cancer therapy. Reactive oxygen species (ROS) responsive nonviral gene delivery is the most widely explored strategy for such applications, yet the development of fast and safe ROS responsive nanocarriers proves to be a challenge because of the intracellular chemical equilibrium of high ROS and glutathione levels. Here, we report an ultrasound-enhanced ROS responsive charge-reversal polymeric nanocarrier (BTIL) for fast and efficient pancreatic cancer gene delivery. The BTIL is composed of B-PDEAEA/DNA polyplex-based cores and IR780-loaded liposome coatings. The IR780 is able to produce an excess of ROS under low intensity ultrasound irradiation, thus disequilibrating the chemical equilibrium of ROS and glutathione, and promoting the ROS-responsive positive-to-negative charge-reversal of the B-PDEAEA polymer. This charge conversion results in fast polyplex dissociation and intracellular gene release, inducing efficient gene transfection and cancer cell apoptosis. Moreover, following the intravenous administration, BTIL maintains a stable and long circulation in the bloodstream, achieves orthotopic pancreatic ductal adenocarcinoma distribution, and exhibits potent antitumor activity with negligible side effects. Our results reveal the proposed strategy to be both promising and universal for the development of fast and safe ROS responsive nonviral gene delivery in cancer therapy.

Glutamate Dehydrogenase Functions in Glutamic Acid Metabolism and Stress Resistance in Pyropia haitanensis.

Pyropia haitanensis is an important laver species in China. Its quality traits are closely related to the content of glutamic acid. Glutamate dehydrogenase (GDH) is a crucial enzyme in the glutamic acid metabolism. In this study, two GDH genes from P. haitanensis, PhGDH1 and PhGDH2, were cloned and successfully expressed in Escherichia coli. The in vitro enzyme activity assay demonstrated that the catalytic activity of PhGDHs is mainly in the direction of ammonium assimilation. The measured Km values of PhGDH1 for NADH, (NH4)2SO4, and α-oxoglutarate were 0.12, 4.99, and 0.16 mM, respectively, while the corresponding Km values of PhGDH2 were 0.02, 3.98, and 0.104 mM, respectively. Site-directed mutagenesis results showed that Gly193 and Thr361 were important catalytic residues for PhGDH2. Moreover, expression levels of both PhGDHs were significantly increased under abiotic stresses. These results suggest that PhGDHs can convert α-oxoglutarate to glutamic acid, and enhance the flavor and stress resistance of P. haitanensis.

Genome-Wide Mapping of Cytosine Methylation Revealed Dynamic DNA Methylation Patterns Associated with Sporophyte Development of Saccharina japonica.

Cytosine methylation plays vital roles in regulating gene expression and plant development. However, the function of DNA methylation in the development of macroalgae remains unclear. Through the genome-wide bisulfite sequencing of cytosine methylation in holdfast, stipe and blade, we obtained the complete 5-mC methylation landscape of Saccharina japonica sporophyte. Our results revealed that the total DNA methylation level of sporophyte was less than 0.9%, and the content of CHH contexts was dominant. Moreover, the distribution of CHH methylation within the genes exhibited exon-enriched characteristics. Profiling of DNA methylation in three parts revealed the diverse methylation pattern of sporophyte development. These pivotal DMRs were involved in cell motility, cell cycle and cell wall/membrane biogenesis. In comparison with stipe and blade, hypermethylation of mannuronate C5-epimerase in holdfast decreased the transcript abundance, which affected the synthesis of alginate, the key component of cell walls. Additionally, 5-mC modification participated in the regulation of blade and holdfast development by the glutamate content respectively via glutamine synthetase and amidophosphoribosyl transferase, which may act as the epigenetic regulation signal. Overall, our study revealed the global methylation characteristics of the well-defined holdfast, stipe and blade, and provided evidence for epigenetic regulation of sporophyte development in brown macroalgae.

Low-Intensity Focused Ultrasound-Responsive Ferrite-Encapsulated Nanoparticles for Atherosclerotic Plaque Neovascularization Theranostics.

Pathological angiogenesis is a crucial factor that causes atherosclerotic plaque rupture. Sinoporphyrin sodium-mediated sonodynamic therapy (DVDMS-SDT) induces regression of plaque neovascularization in humans without causing obvious side effects. However, a clinical noninvasive theranostic strategy for atherosclerotic plaque neovascularization is urgently needed. A nanoplatform designed for multimodality imaging-guided SDT in plaque angiogenesis theranostics, termed PFP-HMME@PLGA/MnFe2 O4 -ramucirumab nanoparticles (PHPMR NPs), is fabricated. It encapsulates manganese ferrite (MnFe2 O4 ), hematoporphyrin monomethyl ether (HMME), and perfluoropentane (PFP) stabilized by polylactic acid-glycolic acid (PLGA) shells and is conjugated to an anti-VEGFR-2 antibody. With excellent magnetic resonance imaging (MRI)/photoacoustic/ultrasound imaging ability, the distribution of PHPMR NPs in plaque can be observed in real time. Additionally, they actively accumulate in the mitochondria of rabbit aortic endothelial cells (RAECs), and the PHPMR NP-mediated SDT promotes mitochondrial-caspase apoptosis via the production of reactive oxygen species and inhibits the proliferation, migration, and tubulogenesis of RAECs. On day 3, PHPMR NP-mediated SDT induces apoptosis in neovessel endothelial cells and improves hypoxia in the rabbit advanced plaque. On day 28, PHPMR NP-mediated SDT reduces the density of neovessels, subsequently inhibiting intraplaque hemorrhage and inflammation and eventually stabilizing the plaque. Collectively, PHPMR NP-mediated SDT presents a safe and effective theranostic strategy for inhibiting plaque angiogenesis.

Ferrite-encapsulated nanoparticles with stable photothermal performance for multimodal imaging-guided atherosclerotic plaque neovascularization therapy.

Pathological angiogenesis is a critical contributor to atherosclerotic plaque rupture. However, there are few effective theranostic strategies to stabilize plaques by suppressing neovascularization. In this study, we fabricated a polymeric nanosystem using 3 nm manganese ferrite (MnFe2O4) and perfluorohexane (PFH) stabilized by polylactic acid-glycolic acid (PLGA) shells and conjugated to the surface of an anti-vascular endothelial growth factor receptor 2 (VEGFR2) antibody [ramucirumab (Ram)]. The PFH@PLGA/MnFe2O4-Ram nanoparticles (NPs) were used as atherosclerotic plaque angiogenesis theranostics for multimodal imaging-guided photothermal therapy (PTT). Three-nanometer MnFe2O4 is an excellent magnetic resonance imaging T1 and photoacoustic imaging contrast agent. Upon exposure to near-infrared (NIR) light, MnFe2O4 in the NPs could transform NIR light into thermal energy for the photothermal elimination of plaque angiogenesis. Additionally, optical droplet vaporization of PFH in the NPs triggered by the thermal effect to form gas bubbles enhanced ultrasound imaging. Our in vitro experiments revealed that PFH@PLGA/MnFe2O4-Ram NPs actively accumulated in rabbit aortic endothelial cells, and NP-mediated PTT promoted endothelial cell apoptosis while inhibiting their proliferation, migration, and tubulogenesis. Notably, the PFH@PLGA/MnFe2O4-Ram NPs possessed excellent photostability and biocompatibility. In the rabbit advanced atherosclerotic plaque model, PFH@PLGA/MnFe2O4-Ram NP-guided PTT significantly induced apoptosis of neovascular endothelial cells and improved the hypoxia status in the plaque 3 days after treatment. On day 28, PTT significantly reduced the density of neovessels and subsequently stabilized rabbit plaques by inhibiting plaque hemorrhage and macrophage infiltration. Collectively, these results suggest that PFH@PLGA/MnFe2O4-Ram NP-guided PTT is a safe and effective theranostic strategy for inhibiting atherosclerotic plaque angiogenesis.

MiR8181 is involved in the cell growth regulation of Saccharina japonica.

Aureochrome, a blue-light receptor specifically found in photosynthetic stramenopiles, plays an important role in algal growth and development. It holds a reversed effector-sensor topology for the reception of blue light, acting as a candidate of optogenetic tool in transcriptional regulation. However, the inner regulatory mechanism of aureochrome is still unclear. In this study, we explored the potential regulatory relationship between microRNAs (miRNAs) and mRNAs by small RNA, transcriptome and degradome sequencing in Saccharina japonica. Through screening miRNA-mRNA interaction networks at the whole-genome level, we found that 18 miRNAs perfectly paired with aureochrome. Among these screened miRNAs, miR8181 was negatively correlated with aureochrome5 with high credibility, exhibiting tissue-specific expression in sporophyte of S. japonica. Degradome analysis further revealed the exact cleavage site of miR8181 on aureochrome5, confirming their targeting relationship. For the 54 target genes of miR8181, nine genes that exhibited similar expression to that of aureochrome5 competed for the same binding site, thus establishing a competing endogenous RNA network. Functional enrichment of the target genes revealed that miR8181 was involved in the regulation of cell differentiation and development in S. japonica. Moreover, overexpression of miR8181 resulted in significant decreases in the cell growth rates of Phaeodactylum tricornutum, suggesting negative roles of miR8181 in regulating cell growth. Our study revealed that miR8181, the targeting miRNA of aureochrome5, played negative roles in cell growth and development.

Sonodynamic therapy reduces iron retention of hemorrhagic plaque.

Intraplaque hemorrhage (IPH) plays a major role in the aggressive progression of vulnerable plaque, leading to acute cardiovascular events. We previously demonstrated that sonodynamic therapy (SDT) inhibits atherosclerotic plaque progression. In this study, we investigated whether SDT could also be applied to treat more advanced hemorrhagic plaque and addressed the underlying mechanism. SDT decreased atherosclerotic burden, positively altered atherosclerotic lesion composition, and alleviated iron retention in rabbit hemorrhagic plaques. Furthermore, SDT reduced iron retention by stimulating ferroportin 1 (Fpn1) expression in apolipoprotein E (ApoE)-/- mouse plaques with high susceptibility to IPH. Subsequently, SDT inhibited iron-overload-induced foam-cell formation and pro-inflammatory cytokines secretion in vitro. Moreover, SDT reduced levels of the labile iron pool and ferritin expression via the reactive oxygen species (ROS)-nuclear factor erythroid 2-related factor 2 (Nrf2)-FPN1 pathway. SDT exerted therapeutic effects on hemorrhagic plaques and reduced iron retention via the ROS-Nrf2-FPN1 pathway in macrophages, thereby suggesting that it is a potential translational strategy for patients with advanced atherosclerosis in clinical practice.

Early modulation of macrophage ROS-PPARγ-NF-κB signalling by sonodynamic therapy attenuates neointimal hyperplasia in rabbits.

Disruption of re-endothelialization and haemodynamic balance remains a critical side effect of drug-eluting stents (DES) for preventing intimal hyperplasia. Previously, we found that 5-aminolevulinic acid-mediated sonodynamic therapy (ALA-SDT) suppressed macrophage-mediated inflammation in atherosclerotic plaques. However, the effects on intimal hyperplasia and re-endothelialization remain unknown. In this study, 56 rabbits were randomly assigned to control, ultrasound, ALA and ALA-SDT groups, and each group was divided into two subgroups (n = 7) on day 3 after right femoral artery balloon denudation combined with a hypercholesterolemic diet. Histopathological analysis revealed that ALA-SDT enhanced macrophage apoptosis and ameliorated inflammation from day 1. ALA-SDT inhibited neointima formation without affecting re-endothelialization, increased blood perfusion, decreased the content of macrophages, proliferating smooth muscle cells (SMCs) and collagen but increased elastin by day 28. In vitro, ALA-SDT induced macrophage apoptosis and reduced TNF-α, IL-6 and IL-1ß via the ROS-PPARγ-NF-κB signalling pathway, which indirectly inhibited human umbilical artery smooth muscle cell (HUASMC) proliferation, migration and IL-6 production. ALA-SDT effectively inhibits intimal hyperplasia without affecting re-endothelialization. Hence, its clinical application combined with bare-metal stent (BMS) implantation presents a potential strategy to decrease bleeding risk caused by prolonged dual-antiplatelet regimen after DES deployment.

Low molecular weight fucoidan alleviates diabetic nephropathy by binding fibronectin and inhibiting ECM-receptor interaction in human renal mesangial cells.

Diabetic nephropathy (DN) is the most common cause of end-stage renal disease (ESRD). Currently, approximately 20-40% of individuals with diabetes are diagnosed with DN. Mesangial cells (MCs) are critical for maintaining and regulating glomerular filtration, and the abnormal proliferation of MCs causes the accumulation of mesangial extracellular matrix (ECM), further promoting glomerular dysfunction and renal diseases. Low molecular weight fucoidan (LMWF) extracted from Saccharina japonica could alleviate DN, but the mechanism was not analysed. Based on the ability of LMWF to ameliorate the human renal mesangial cell (HRMC) injury caused by advanced glycation end products (AGEs), we identified fibronectin (FN) as the most obviously impacted protein in the ECM-receptor interaction by proteomic analysis. The co-localization of LMWF and FN indicated direct interaction between them, and surface plasmon resonance (SPR) analysis confirmed the specific binding with a KD of 453.7 µmol L-1. Positively charged protamine sulfate (PS) promoted the combination of LMWF and HRMCs and further enhanced the effect of LMWF on HRMC injury. Our results indicated that LMWF alleviates the HRMC injury caused by AGEs via binding FN and inhibiting the ECM-receptor interaction pathway. These results provide a foundation for the in-depth analysis of the mechanism of polysaccharide functions.

Sonodynamic Therapy Suppresses Neovascularization in Atherosclerotic Plaques via Macrophage Apoptosis-Induced Endothelial Cell Apoptosis.

During atherosclerosis plaque progression, pathological intraplaque angiogenesis leads to plaque rupture accompanied by thrombosis, which is probably the most important cause of arteries complications such as cerebral and myocardial infarction. Even though few treatments are available to mitigate plaque rupture, further investigation is required to develop a robust optimized therapeutic method. In this study using rabbit and mouse atherosclerotic models, sinoporphyrin sodium (DVDMS)-mediated sonodynamic therapy reduced abnormal angiogenesis and plaque rupture. Briefly, DVDMS is injected to animals, and then the plaque was locally exposed to pulse ultrasound for a few minutes. Furthermore, a small size clinical trial was conducted on patients with atherosclerosis. Notably, a significant reduction of arterial inflammation and angiogenesis was recorded following a short period of DVDMS-mediated sonodynamic therapy treatment. This beneficial outcome was almost equivalent to the therapeutic outcome after 3-month intensive statin treatment.

Non-Coding RNAs Participate in the Regulation of CRY-DASH in the Growth and Early Development of Saccharina japonica (Laminariales, Phaeophyceae).

CRY-DASH, a new cryptochrome blue light receptor, can repair damaged DNA and regulate secondary metabolism and development of fungus. However, its role in regulation during the growth of Saccharina japonica is still unclear. After cloning the full-length of CRY-DASH from S. japonica (sjCRY-DASH), we deduced that its open reading frame was 1779 bp long and encoded 592 amino acids. sjCRY-DASH transcription was rapidly upregulated within 30 min in response to blue light and exhibited 24 h periodicity with different photoperiods. Moreover, sjCRY-DASH maintained the same periodicity in suitable growth temperature, suggesting a close relationship between this periodicity and circadian rhythm regulation. Novel-m3234-5p, which was targeted to sjCRY-DASH, decreased with increasing sjCRY-DASH transcription, acting as a negative modulator of sjCRY-DASH. Six long non-coding RNAs classified as long intergenic non-coding RNAs (lincRNAs) exhibited co-expression with sjCRY-DASH. A miRNA sjCRY DASH lincRNA network was consequently identified. By predicting the endogenous competing mRNAs of novel-m3234-5p, we found that sjCRY-DASH indirectly participated in the regulation of DNA damage repair, protein synthesis and processing, and actin transport. In conclusion, our results revealed that non-coding RNAs participate in the regulation of sjCRY-DASH, which played vital roles in the growth and early development of S. japonica.

Verification of the Saccharina japonica Translocon Tic20 and its Localization in the Chloroplast Membrane in Diatoms.

Tic20 is an important translocon protein that plays a role in protein transport in the chloroplast. The sequence of Tic20 was determined in the lower brown alga Saccharina japonica. Structural analysis of SjTic20 revealed a noncanonical structure consisting of an N-terminal non-cyanobacterium-originated EF-hand domain (a helix-loop-helix structural domain) and a C-terminal cyanobacterium-originated Tic20 domain. Subcellular localization and transmembrane analysis indicated that SjTic20 featured an "M"-type Nin-Cin-terminal orientation, with four transmembrane domains in the innermost membrane of the chloroplast in the microalga Phaeodactylum tricornutum, and the EF-hand domain was entirely extruded into the chloroplast stroma. Our study provides information on the structure, localization, and topological features of SjTic20, and further functional analysis of SjTic20 in S. japonica is needed.

The 40S Ribosomal Protein S6 Response to Blue Light by Interaction with SjAUREO in Saccharina japonica.

Blue light (BL) plays an important role in regulation of the growth and development of aquatic plants and land plants. Aureochrome (AUREO), the recent BL photoreceptor identified in photosynthetic stramenopile algae, is involved in the photomorphogenesis and early development of Saccharina japonica porophytes (kelp). However the factors that interact with the SjAUREO under BL conditions specifically are not clear. Here in our study, three high quality cDNA libraries with CFU over 5 × 106 and a recombination rate of 100% were constructed respectively through white light (WL), BL and darkness (DK) treatments to the juvenile sporophytes. Based on the constructed cDNA libraries, the interactors of SjAUREO were screened and analyzed. There are eighty-four genes encoding the sixteen predicted proteins from the BL cDNA library, sixty-eight genes encoding eighteen predicted proteins from the DK cDNA library, and seventy-four genes encoding nineteen proteins from the WL cDNA library. All the predicted proteins are presumed to interact with SjAUREO when co-expressed with SjAUREO seperately. The 40S ribosomal protein S6 (RPS6), which only exists in the BL treated cDNA library except for two other libraries, and which is essential for cell proliferation and is involved in cell cycle progression, was selected for detailed analysis. We showed that its transcription was up-regulated by BL, and was highly transcribed in the basal blade (meristem region) of juvenile sporophytes but less in the distal part. Taken together, our results indicated that RPS6 was highly involved in BL-mediated kelp cellular division and photomorphogenesis by interacting with SjAUREO.

Phylogeographic diversification and postglacial range dynamics shed light on the conservation of the kelp Saccharina japonica.

Studies of postglacial range shifts could enhance our understanding of seaweed species' responses to climate change and hence facilitate the conservation of natural resources. However, the distribution dynamics and phylogeographic diversification of the commercially and ecologically important kelp Saccharina japonica in the Northwest Pacific (NWP) are still poorly surveyed. In this study, we analyzed the evolutionary history of S. japonica using two mitochondrial markers and 24 nuclear microsatellites. A STRUCTURE analysis revealed two partially isolated lineages: lineage H, which is scattered along the coast of Japan; and lineage P, which occurs along the west coast of the Japan Sea. Ecological niche modeling projections to the Last Glacial Maximum (LGM) revealed that the southern coasts of the Japan Sea and the Pacific side of the Oshima and Honshu Peninsulas provided the most suitable habitats for S. japonica, implying that these regions served as ancient refugia during the LGM. Ancient isolation in different refugia may explain the observed divergence between lineages P and H. An approximate Bayesian computation analysis indicated that the two lineages experienced post-LGM range expansion and that postglacial secondary contact occurred in Sakhalin. Model projections into the year 2,100 predicted that S. japonica will shift northwards and lose its genetic diversity center on the Oshima Peninsula in Hokkaido and Shimokita Peninsula in Honshu. The range shifts and evolutionary history of S. japonica improve our understanding of how climate change impacted the distribution range and diversity of this species and provide useful information for the conservation of natural resources under ongoing environmental change in the NWP.