Phytoplankton-derived polysaccharides and microbial peptidoglycans are key nutrients for deep-sea microbes in the Mariana Trench.

BACKGROUND: The deep sea represents the largest marine ecosystem, driving global-scale biogeochemical cycles. Microorganisms are the most abundant biological entities and play a vital role in the cycling of organic matter in such ecosystems. The primary food source for abyssal biota is the sedimentation of particulate organic polymers. However, our knowledge of the specific biopolymers available to deep-sea microbes remains largely incomplete. One crucial rate-limiting step in organic matter cycling is the depolymerization of particulate organic polymers facilitated by extracellular enzymes (EEs). Therefore, the investigation of active EEs and the microbes responsible for their production is a top priority to better understand the key nutrient sources for deep-sea microbes. RESULTS: In this study, we conducted analyses of extracellular enzymatic activities (EEAs), metagenomics, and metatranscriptomics from seawater samples of 50-9305 m from the Mariana Trench. While a diverse array of microbial groups was identified throughout the water column, only a few exhibited high levels of transcriptional activities. Notably, microbial populations actively transcribing EE genes involved in biopolymer processing in the abyssopelagic (4700 m) and hadopelagic zones (9305 m) were primarily associated with the class Actinobacteria. These microbes actively transcribed genes coding for enzymes such as cutinase, laccase, and xyloglucanase which are capable of degrading phytoplankton polysaccharides as well as GH23 peptidoglycan lyases and M23 peptidases which have the capacity to break down peptidoglycan. Consequently, corresponding enzyme activities including glycosidases, esterase, and peptidases can be detected in the deep ocean. Furthermore, cell-specific EEAs increased at 9305 m compared to 4700 m, indicating extracellular enzymes play a more significant role in nutrient cycling in the deeper regions of the Mariana Trench. CONCLUSIONS: Transcriptomic analyses have shed light on the predominant microbial population actively participating in organic matter cycling in the deep-sea environment of the Mariana Trench. The categories of active EEs suggest that the complex phytoplankton polysaccharides (e.g., cutin, lignin, and hemicellulose) and microbial peptidoglycans serve as the primary nutrient sources available to deep-sea microbes. The high cell-specific EEA observed in the hadal zone underscores the robust polymer-degrading capacities of hadal microbes even in the face of the challenging conditions they encounter in this extreme environment. These findings provide valuable new insights into the sources of nutrition, the key microbes, and the EEs crucial for biopolymer degradation in the deep seawater of the Mariana Trench. Video Abstract.

Amide proton transfer weighted contrast has diagnostic capacity in detecting diabetic foot: an MRI-based case-control study.

Objective: To evaluate the role of foot muscle amide proton transfer weighted (APTw) contrast and tissue rest perfusion in quantifying diabetic foot (DF) infection and its correlation with blood parameters. Materials and methods: With approval from an ethical review board, this study included 40 diabetes mellitus (DM) patients with DF and 31 DM patients without DF or other lower extremity arterial disease. All subjects underwent MRI, which included foot sagittal APTw and coronal arterial spin labeling (ASL) imaging. The normalized MTRasym (3.5 ppm) and the ratio of blood flow (rBF) in rest status of the affected side lesions to the non-affected contralateral side were determined. The inter-group differences of these variables were evaluated. Furthermore, the association between normalized MTRasym (3.5 ppm), rBF, and blood parameters [fasting blood glucose (FBG), glycosylated hemoglobin content, C-reactive protein, neutrophil percentage, and white blood cell count] was explored. Using an ROC curve, the diagnostic capacity of normalized MTRasym (3.5 ppm), BF, and blood biochemical markers in differentiating with or without DF in DM was assessed. Results: In the DF group, MTRasym (3.5 ppm) and BF in lesion and normalized MTRasym (3.5 ppm) were higher than those in the control group (p < 0.05). In addition, correlations were identified between normalized MTRasym (3.5 ppm) and blood parameters, such as C-reactive protein, glycosylated hemoglobin content, FBG, neutrophil ratio, and white blood cell (p < 0.001). Meanwhile, association between BF in lesion and blood parameters, such as C-reactive protein, neutrophil percentage, and FBG (p < 0.01). AUC of normalized MTRasym (3.5 ppm) in identifying with/without DF in patients with DM is 0.986 (95% CI, 0.918-1.00) with the sensitivity of 97.22% and the specificity of 100%. Conclusion: Normalized MTRasym (3.5 ppm) and the BF in lesion may be treated as a safer and more convenient new indicator to evaluate the tissue infection without using a contrast agent, which may be useful in monitoring and preoperatively assessing DF patients with renal insufficiency.

Clinical effects of cocktail injection on the thoracolumbar fascia injury during percutaneous vertebroplasty for osteoporotic vertebral compression fractures: a single-center, retrospective case-control study.

BACKGROUND: Nowadays, there is a lack of effective intraoperative treatment for thoracolumbar fascia injury (TFI) of osteoporotic vertebral compression fractures (OVCFs), which may lead to postoperative residual pain. We aimed to evaluate the clinical effects of cocktail injection on the TFI during percutaneous vertebroplasty (PVP) for OVCFs. METHODS: A retrospective study of OVCFs with TFI underwent PVP with cocktail injection (Cocktail group, 58 cases) or PVP (Routine group, 64 cases) was conducted. The surgical outcomes, visual analog scale (VAS) score, oswestry disability index (ODI), incidence of residual pain at 1 day and 7 days postoperatively, the rate and duration of taking painkillers during 7 days postoperatively after PVP were compared between them. RESULTS: No differences in baseline data, volume of bone cement injected and bone cement leakage were observed between the two groups, while the operation time of the routine group (44.3 ± 7.8 min) was less than that (47.5 ± 9.1 min) of the cocktail group (P < 0.05). However, the VAS scores (2.4 ± 0.8, 2.2 ± 0.7), ODI (25.2 ± 4.2, 22.3 ± 2.9), the incidence of residual pain (8.6%, 3.4%) at 1 and 7 days postoperatively, the rate (6.9%) and duration ( 2.5 ± 0.6 ) of taking painkillers during 7 days postoperatively in the cocktail group were better than those (3.4 ± 1.0, 2.9 ± 0.7, 34.1 ± 4.7, 28.6 ± 3.6, 23.4%, 15.6%, 28.1%, 4.2 ± 1.4) in the routine group (P < 0.05), respectively. CONCLUSION: PVP combined with cocktail injection increased the operation time in the treatment of OVCFs with TFI, but it can more effectively relieve pain, reduce the risk of residual pain at 1 day and 7 days postoperatively, and decrease the use and duration of taking painkillers.

From process to product: writing engagement and performance of EFL learners under computer-generated feedback instruction.

Artificial intelligence (AI) technology is gradually penetrating the domain of education, opening up many possibilities for teaching and learning. Many educators, faced with the burden of commenting on substantial student essays, have introduced automated writing evaluation (AWE) into second language (L2) writing considering its affordance of immediate scores and diagnostic information. However, students' processing strategies and perceptions of such computer-generated feedback and its impact on student writing quality, particularly as mediated by language proficiency, remain under-explored. This study examines the impact of Pigai, a Chinese AWE system, on revision processes and writing products of 42 English as a foreign language (EFL) learners with varying language levels by analyzing feedback points, feedback uptake, text quality in complexity, accuracy, and fluency (CAF), and perceptions. The findings are as follows. When confronted with AWE instruction, the majority of student work focuses on correcting errors, but higher-level students exhibit an emphasis on language improvement beyond the surface level compared to lower-level students. According to CAF measures, automated feedback exerts greater effects on accuracy for unskilled learners and lexical complexity for skilled learners in the development of interlanguage. Learner profiles and perceptions of students at different levels are explored along four dimensions: writing quality, cognitive engagement, behavioral engagement, and affective engagement. Finally, the potential issues of such technology-based writing instruction are pointed out.

A corpus-based comparison of syntactic complexity in academic writing of L1 and L2 English students across years and disciplines.

Syntactic complexity, widely acknowledged as a key predictor of writing quality, has gained increasing attention in the realm of academic writing. A notable line of inquiry has centered on the factors that potentially influence syntactic complexity in academic writing. Instead of attending to one factor, the study focuses on multiple factors to examine how language background affects syntactic complexity across years and disciplines. Specifically, it compares the syntactic complexity in English academic writing between L1 English and L1 Chinese university students across four years and/or three disciplines. Fine-grained indices, which include five clausal indices and eight phrasal indices, are utilized to capture specific syntactic features for a full understanding and description of the syntactic preferences shown by L1 English and L1 Chinese students in academic discourse. The results revealed that L1 English students tended to produce more noun phrases in academic writing than L1 Chinese students with the increase of years. Additionally, both cohorts of students followed similar syntactic patterns in cross-disciplinary contexts, with highly frequent use of complex nominals in the Physical Sciences and clausal structures in the Social Sciences. In instances where language background, year, and discipline interact, texts produced by Chinese English learners exhibited reliance on the syntactic features of adverbial clauses, attributive adjectives, and pre-modifying nouns across all disciplines in the early years of their academic journey. Ultimately, some pedagogical implications for academic writing courses are put forward in an attempt to provide valuable insights for enhancing academic literacy among both L1 and L2 students.

A moderately thermophilic origin of a novel family of marine group II euryarchaeota from deep ocean.

Marine group II (MGII) is the most abundant planktonic heterotrophic archaea in the ocean. The evolutionary history of MGII archaea is elusive. In this study, 13 new MGII metagenome-assembled genomes were recovered from surface to the hadal zone in Challenger Deep of the Mariana Trench; four of them from the deep ocean represent a novel group. The optimal growth temperature (OGT) of the common ancestor of MGII has been estimated to be at about 60°C and OGTs of MGIIc, MGIIb, and MGIIa at 47°C-50ºC, 37°C-44ºC, and 30°C-37ºC, respectively, suggesting the adaptation of these species to different temperatures during evolution. The estimated OGT range of MGIIc was supported by experimental measurements of cloned ß-galactosidase that showed optimal enzyme activity around 50°C. These results indicate that MGIIc may have originated from a common ancestor that lived in warm or even hot marine environment, such as hydrothermal vents.

Identification of hidden N4-like viruses and their interactions with hosts.

IMPORTANCE: The findings of this study are significant, as N4-like viruses represent a unique viral lineage with a distinct replication mechanism and a conserved core genome. This work has resulted in a comprehensive global map of the entire N4-like viral lineage, including information on their distribution in different biomes, evolutionary divergence, genomic diversity, and the potential for viral-mediated host metabolic reprogramming. As such, this work significantly contributes to our understanding of the ecological function and viral-host interactions of bacteriophages.

The treatment of tuberculosis in the upper thoracic spine using the small incision technique through the third rib.

Background: The complex anatomical structure of the upper thoracic spine makes it challenging to achieve surgical exposure, resulting in significant surgical risks and difficulties. Posterior surgery alone fails to adequately address and reconstruct upper thoracic lesions due to limited exposure. While the anterior approach offers advantages in fully exposing the anterior thoracic lesions, the surgical procedure itself is highly intricate. Although there exist various anterior approaches for the upper thoracic spine, the incidence of upper thoracic spine lesions is relatively low. Consequently, there are limited reports on the treatment and reconstruction of upper thoracic spine lesions using the third rib small incision approach in the context of upper thoracic tuberculosis. Methods: We collected data from four patients with upper thoracic tuberculosis who were admitted to our department between July 2017 and November 2022. The treatment for upper thoracic tuberculosis involved utilizing the third rib small incision approach, which included two cases of thoracic 3-4 vertebral tuberculosis, one case of thoracic 4 vertebral tuberculosis, and one case of thoracic 5 vertebral tuberculosis. Among the patients, three were positioned in the left lateral position, while one was positioned in the right lateral position. Prior to admission, all four patients received a two-week course of oral medication, consisting of isoniazid, rifampicin, pyrazinamide, and ethambutol. After the surgical procedure, they continued receiving anti-tuberculosis treatment for a duration of 12 months. Results: The average duration of the surgical procedure was 150 min, with an average blood loss of 500 ml. One patient exhibited symptoms of brachial plexus injury, which gradually improved after careful observation. All patients experienced primary wound healing, and no complications such as pulmonary infection, respiratory failure, or other adverse events were observed. Additionally, one patient showed elevated transaminase levels, leading to a modification in the anti-tuberculosis drug regimen from quadruple therapy to triple therapy. Conclusion: The treatment of upper thoracic tuberculosis through the third rib small incision technique is a very good surgical approach, which has the advantages of safety and effectiveness.

Deep-sea Bacteroidetes from the Mariana Trench specialize in hemicellulose and pectin degradation typically associated with terrestrial systems.

BACKGROUND: Hadal trenches (>6000 m) are the deepest oceanic regions on Earth and depocenters for organic materials. However, how these enigmatic microbial ecosystems are fueled is largely unknown, particularly the proportional importance of complex polysaccharides introduced through deposition from the photic surface waters above. In surface waters, Bacteroidetes are keystone taxa for the cycling of various algal-derived polysaccharides and the flux of carbon through the photic zone. However, their role in the hadal microbial loop is almost unknown. RESULTS: Here, culture-dependent and culture-independent methods were used to study the potential of Bacteroidetes to catabolize diverse polysaccharides in Mariana Trench waters. Compared to surface waters, the bathypelagic (1000-4000 m) and hadal (6000-10,500 m) waters harbored distinct Bacteroidetes communities, with Mesoflavibacter being enriched at ≥ 4000 m and Bacteroides and Provotella being enriched at 10,400-10,500 m. Moreover, these deep-sea communities possessed distinct gene pools encoding for carbohydrate active enzymes (CAZymes), suggesting different polysaccharide sources are utilised in these two zones. Compared to surface counterparts, deep-sea Bacteroidetes showed significant enrichment of CAZyme genes frequently organized into polysaccharide utilization loci (PULs) targeting algal/plant cell wall polysaccharides (i.e., hemicellulose and pectin), that were previously considered an ecological trait associated with terrestrial Bacteroidetes only. Using a hadal Mesoflavibacter isolate (MTRN7), functional validation of this unique genetic potential was demonstrated. MTRN7 could utilize pectic arabinans, typically associated with land plants and phototrophic algae, as the carbon source under simulated deep-sea conditions. Interestingly, a PUL we demonstrate is likely horizontally acquired from coastal/land Bacteroidetes was activated during growth on arabinan and experimentally shown to encode enzymes that hydrolyze arabinan at depth. CONCLUSIONS: Our study implies that hadal Bacteroidetes exploit polysaccharides poorly utilized by surface populations via an expanded CAZyme gene pool. We propose that sinking cell wall debris produced in the photic zone can serve as an important carbon source for hadal heterotrophs and play a role in shaping their communities and metabolism. Video Abstract.

MAPK8 and CAPN1 as potential biomarkers of intervertebral disc degeneration overlapping immune infiltration, autophagy, and ceRNA.

Background: Intervertebral disc degeneration (IDD) is one of the most common health problems in the elderly and a major causative factor in low back pain (LBP). An increasing number of studies have shown that IDD is closely associated with autophagy and immune dysregulation. Therefore, the aim of this study was to identify autophagy-related biomarkers and gene regulatory networks in IDD and potential therapeutic targets. Methods: We obtained the gene expression profiles of IDD by downloading the datasets GSE176205 and GSE167931 from the Gene Expression Omnibus (GEO) public database. Subsequently, differentially expressed genes (DEGs) analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, gene ontology (GO), and gene set enrichment analysis (GSEA) were performed to explore the biological functions of DEGs. Differentially expressed autophagy-related genes (DE-ARGs) were then crossed with the autophagy gene database. The hub genes were screened using the DE-ARGs protein-protein interaction (PPI) network. The correlation between the hub genes and immune infiltration and the construction of the gene regulatory network of the hub genes were confirmed. Finally, quantitative PCR (qPCR) was used to validate the correlation of hub genes in a rat IDD model. Results: We obtained 636 DEGs enriched in the autophagy pathway. Our analysis revealed 30 DE-ARGs, of which six hub genes (MAPK8, CTSB, PRKCD, SNCA, CAPN1, and EGFR) were identified using the MCODE plugin. Immune cell infiltration analysis revealed that there was an increased proportion of CD8+ T cells and M0 macrophages in IDD, whereas CD4+ memory T cells, neutrophils, resting dendritic cells, follicular helper T cells, and monocytes were much less abundant. Subsequently, the competitive endogenous RNA (ceRNA) network was constructed using 15 long non-coding RNAs (lncRNAs) and 21 microRNAs (miRNAs). In quantitative PCR (qPCR) validation, two hub genes, MAPK8 and CAPN1, were shown to be consistent with the bioinformatic analysis results. Conclusion: Our study identified MAPK8 and CAPN1 as key biomarkers of IDD. These key hub genes may be potential therapeutic targets for IDD.

Comparison of Wiltse Approach of Pedicle Screw Fixation With or Without Vertebroplasty in the Treatment of Genant III Degree Osteoporotic Thoracolumbar Fractures: Analysis of Clinical Findings, Radiographic Parameters, and Follow-Up Complications.

STUDY DESIGN: A retrospective case-control study. OBJECTIVE: This study aimed to compare the effects of the Wiltse approach of pedicle screw fixation (PSF) either in combination with or without vertebroplasty (VP) in the treatment of Genant III degree osteoporotic thoracolumbar fractures (Genant III-OTLFs). METHODS: A retrospective study of Genant III-OTLFs was performed from January 2018 to December 2019, including 54 cases of PSF + VP and 56 cases of PSF. Clinical indicators [visual analog scale (VAS) score, Oswestry disability index (ODI)], radiographic parameters [local kyphosis angle (LKA), percentage of anterior, central, and posterior vertebral heights (AVH%, CVH%, and PVH%, respectively)] and follow-up complications [adjacent vertebral fracture (AVF), residual pain (RP), vertebral height loss (VHL), and internal fixation failure (IFF)] were compared between the 2 groups. RESULTS: No differences in surgical outcomes, clinical indicators, and radiographic parameters were observed between the 2 groups during the preoperation period and 7 days post-operatively (P > .05). However, the VAS score [2.0 (.6), 1.9 (.5)], ODI [23.7 (4.0), 22.6 (3.0)], LKA [9.5 (1.8), 10.6 (3.0)], AVH% [90.1 (2.7), 87.7 (6.0)], CVH% [92.5 (2.6), 91.3 (3.7)], and PVH% [93.4 (2.0), 92.7 (2.4)] at 1 year post-operatively and last follow-up of the PSF + VP group were better than those of the PSF group [2.5 (.8), 3.1 (1.1), 26.6 (3.8), 29.6 (4.6), 12.2 (1.6), 16.6 (3.2), 84.9 (4.0), 69.9 (6.6), 88.1 (3.1), 78.2 (5.1), 89.7 (2.3), 84.8 (4.6)], respectively (P < .001). During follow-up, the incidence of AVF had no difference (P > .05), while that of RP (32.1 vs 14.8%), VHL (33.9 vs 9.3%) and IFF (17.9 vs 5.6%) had statistical differences between them (P < .05). CONCLUSION: The Wiltse approach of PSF combined with VP for Genant III-OTLFs can not only effectively relieve pain, restore vertebral height, and correcte kyphosis, but also better maintain vertebral height, delay kyphosis progression, and reduce complications during follow-up.

Increasing deep-water overflow from the Pacific into the South China Sea revealed by mooring observations.

Cold and dense water from the North Pacific Ocean that spills through the Luzon Strait, the only deep conduit between the South China Sea (SCS) and the Pacific Ocean, renews deep-water mass, modulates hydrographic and biogeochemical cycles, and drives abyssal and overturning circulations in the SCS. The variability of this key oceanic process, however, has been poorly studied, mainly due to a lack of sustained observations. A comprehensive observational program that started in 2009 has provided 12 years of continuous time series of velocity and volume transport within the Luzon Strait. Here we show the observation-based assessment of decadal trends of deep-water transport through this vital passage. With the estimated 12-year mean volume transport of the deep-water overflow into the SCS of 0.84 ± 0.39 Sv (1 Sv = 106 m3 s-1), a significant linear upward trend of 9% is revealed during this period. This is consistent with long-term changes in satellite-observed ocean bottom pressure. The results of this study may have broad implications for the overturning circulations and biogeochemical processes, including carbon cycles in this region.

Comparison of clinical effects of percutaneous vertebroplasty with two different puncture approaches on the treatment of thoracolumbar osteoporotic vertebral compression fractures with narrow pedicles: a retrospective controlled study.

PURPOSE: To evaluate the effects of percutaneous vertebroplasty (PVP) with conventional transpedicle approach (CTA) or basal transverse process-pedicle approach (BTPA) on the treatment of thoracolumbar osteoporotic vertebral compression fractures (TL-OVCFs) with narrow pedicles. METHODS: A retrospective study of TL-OVCFs with narrow pedicles was performed, including 78 cases of CTA and 84 cases of BTPA. The surgical outcomes, radiographic parameters [the width and height of the pedicle (PW, PH), the inclination angle of puncture (PIA)] and clinical indicators [visual analog scale (VAS) score, Oswestry Disability Index (ODI)] of two groups were compared. RESULTS: In terms of surgical outcomes of them, there was no difference in operation time (P > 0.05), while the volume of bone cement, the incidence of bone cement leakage and rate of good bone cement distribution were significantly worse in the CTA group (4.4 ± 0.6 ml vs. 5.5 ± 0.5 ml, 37.2% vs. 20.2%, 52.6% vs. 79.8%, P < 0.05). As for radiographic parameters and clinical indicators of them, the differences were not observed in the PH, PW, preoperative VAS score and ODI (P > 0.05), whereas the PIA, VAS score and ODI at 1 day postoperatively were significantly better in the BTPA group (17.3 ± 2.1° vs. 29.6 ± 2.8°, 2.7 ± 0.7 vs. 2.1 ± 0.8, 32.8 ± 4.6 vs. 26.7 ± 4.0, P < 0.05). CONCLUSION: The study provided solid evidence that PVP with BTPA had more advantages in the treatment of TL-OVCFs with narrow pedicles, which can better relieve postoperative pain.

Submesoscale inverse energy cascade enhances Southern Ocean eddy heat transport.

Oceanic eddy-induced meridional heat transport (EHT) is an important process in the Southern Ocean heat budget, the variability of which significantly modulates global meridional overturning circulation (MOC) and Antarctic sea-ice extent. Although it is recognized that mesoscale eddies with scales of ~40-300 km greatly contribute to the EHT, the role of submesoscale eddies with scales of ~1-40 km remains unclear. Here, using two state-of-the-art high-resolution simulations (resolutions of 1/48° and 1/24°), we find that submesoscale eddies significantly enhance the total poleward EHT in the Southern Ocean with an enhancement percentage reaching 19-48% in the Antarctic Circumpolar Current band. By comparing the eddy energy budgets between the two simulations, we detect that the primary role of submesoscale eddies is to strengthen mesoscale eddies (and thus their heat transport capability) through inverse energy cascade rather than directly through submesoscale heat fluxes. Due to the submesoscale-mediated enhancement of mesoscale eddies in the 1/48° simulation, the clockwise upper cell and anti-clockwise lower cell of the residual-mean MOC in the Southern Ocean are weakened and strengthened, respectively. This finding identifies a potential route to improve the mesoscale parameterization in climate models for more accurate simulations of the MOC and sea ice variability in the Southern Ocean.

Virioplankton assemblages from challenger deep, the deepest place in the oceans.

Hadal ocean biosphere, that is, the deepest part of the world's oceans, harbors a unique microbial community, suggesting a potential uncovered co-occurring virioplankton assemblage. Herein, we reveal the unique virioplankton assemblages of the Challenger Deep, comprising 95,813 non-redundant viral contigs from the surface to the hadal zone. Almost all of the dominant viral contigs in the hadal zone were unclassified, potentially related to Alteromonadales and Oceanospirillales. 2,586 viral auxiliary metabolic genes from 132 different KEGG orthologous groups were mainly related to the carbon, nitrogen, sulfur, and arsenic metabolism. Lysogenic viral production and integrase genes were augmented in the hadal zone, suggesting the prevalence of viral lysogenic life strategy. Abundant rve genes in the hadal zone, which function as transposase in the caudoviruses, further suggest the prevalence of viral-mediated horizontal gene transfer. This study provides fundamental insights into the virioplankton assemblages of the hadal zone, reinforcing the necessity of incorporating virioplankton into the hadal biogeochemical cycles.

Mesenchymal stem cell extracellular vesicles-derived microRNA-194-5p delays the development of intervertebral disc degeneration by targeting TRAF6.

OBJECTIVE: Mesenchymal stem cells-derived extracellular vesicles (MSCs-EVs) can improve intervertebral disc degeneration (IDD). Considering that, their concrete mechanisms from microRNA-194-5p/tumor receptor-associated factor 6 (miR-194-5p/TRAF6) axis in IDD ask for disclosure in a scientific way. METHODS: Nucleus pulposus (NP) cells and MSCs were obtained. EVs were isolated from the obtained MSCs and identified. miR-194-5p expression in MSC-EVs was altered by sequence transfection. Subsequently, MSCs-EVs were co-cultured with NP cells intervened by tumor necrosis factor α (TNF-α). NP cell proliferation and apoptosis, along with their osteogenic differentiation ability were evaluated. miR-194-5p and TRAF6 expression and their interaction were determined. RESULTS: In TNF-α-intervened NP cells, miR-194-5p was down-regulated and TRAF6 was up-regulated. Restoring miR-194-5p effectively enhanced proliferation and osteogenic differentiation, and reduced apoptosis of TNF-α-intervened NP cells. miR-194-5p-enriched MSCs-EVs protected TNF-α-intervened NP cells. miR-194-5p targeted TRAF6, TRAF6 overexpression exerted negatively for the growth of TNF-α-intervened NP cells, and could reduce the protective effects of miR-194-5p on TNF-α-intervened NP cells. CONCLUSION: It is elucidated that miR-194-5p derived from MSCs-EVs protects TNF-α-intervened NP cells through restricting TRAF6, replenishing a potential target for IDD treatment.

Halomonas profundi sp. nov., isolated from deep-sea sediment of the Mariana Trench.

Two novel Gram-stain-negative, facultative anaerobic, non-flagellated, rod-shaped bacterial strains, designated MT13T and MT32, were isolated from sediment samples collected from the Mariana Trench at a depth of 8300 m. The two strains grew at -2-30 °C (optimum, 25 °C), at pH 5.5-10.0 (optimum, pH 7.5-8.0) and with 0-15 % (w/v) NaCl (optimum, 3-6 %). They did not reduce nitrate to nitrite nor hydrolyse Tweens 40 and 80, aesculin, casein, starch and DNA. The genomic G+C contents of draft genomes of strain MT13T and MT32 were 52.2 and 54.1 m ol%, respectively. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strains MT13T and MT32 were affiliated with the genus Halomonas, with the highest similarity to the type strain of Halomonas olivaria. The values of average nucleotide identity and in silico DNA-DNA hybridization between strain MT13T and MT32, and between strain MT13T and five closely related type strains of Halomonas species indicated that strains MT13T and MT32 belonged to the same species, but represented a novel species in the genus of Halomonas. The major cellular fatty acids of strains MT13T and MT32 were C16 : 0, summed feature 3(C16 : 1 ω7c/ω6c) and summed feature 8 (C18 : 1 ω7c/ω6c). Major polar lipids of strains MT13T and MT32 included phosphatidylglycerol, phosphatidylethanolamine and diphosphatidylglycerol. Ubiquinone-9 was the predominant respiratory quinone. Based on data from the present polyphasic study, strains MT13T and MT32 represent a novel species of the genus Halomonas, for which the name Halomonas profundi sp. nov. is proposed. The type strain is MT13T (=MCCC 1K06389T=KCTC 82923T).

A dark-tolerant diatom (Chaetoceros) cultured from the deep sea.

Although the extreme conditions of the deep sea are typically not suitable for the growth of photosynthetic algae, accumulating evidence indicates that there are diverse healthy phytoplankton living in this environment. However, living phytoplankton from the deep sea have rarely been isolated and cultivated, and so our understanding of where they come from and how they adapt to (or tolerate) the extreme deep-sea environment is limited. Here, under long-term dark stress and subsequent light treatment, we successfully isolated a diatom from a depth of 1,000 m in the Western Pacific Ocean. Morphological observations and molecular phylogenetic analysis revealed that it is affiliated to the genus Chaetoceros, and thus, we tentatively named it Chaetoceros sp. DS1. We observed that the chloroplast genome of this species, is most closely related to that of Chaetoceros simplex. It was shown to have a strong tolerance to darkness in that it maintained its morphological integrity and vitality for up to 3 months in complete darkness at room temperature. We also demonstrated that Chaetoceros sp. DS1 presented a facultative heterotrophic function. Its growth was promoted by many organic carbon sources (e.g., glycerine, ethanol, and sodium acetate) under low light conditions. However, under dark and high light conditions, the growth promotion effect of organic carbon was not obvious. Indeed, Chaetoceros sp. DS1 grew best under low light conditions, indicating that it likely came from the deeper layer of the euphotic zone. The facultative heterotrophic function of this diatom and tolerance to darkness may help it survive in these conditions or enter a dormant period in the deep sea.

Genome sequencing and comparative genomics analysis of Halomonas sp. MT13 reveal genetic adaptation to deep-sea environment.

Halomonas sp. MT13, a moderately psychrotolerant, piezotolerant and exopolysaccharide-producing bacterium, was isolated from deep-sea sediment of the Mariana Trench at the depth of 8300 m. Here, we report the complete genome sequence of strain MT13 and its genomic characteristics related to deep-sea environmental adaptation by comparing with its three closely related Halomonas species. The genome of strain MT13 contains one circular chromosome of 3,643,760 bp without any plasmid. Gene annotation, Cluster of Orthologous Groups (COG) and KEGG analysis showed that strain MT13 possesses a serial of genes involved in deep-sea environmental adaptation, including ectoine biosynthesis, osmolyte transport, and cold-shock response. Compared with type strains of three closely related Halomonas species, strain MT13 has higher proportions of genes assigned to translation, ribosomal structure and biogenesis, and coenzyme, lipid and inorganic ion transport and metabolism, but lacks genes involved in flagellar assembly. The genome of strain MT13 would deepen our knowledge on the adaptation strategies of microorganisms dwelling in deep-sea environment.