Functional vertical connectivity of microbial communities in the ocean.

Sinking particles are a critical conduit for the transport of surface microbes to the ocean's interior. Vertical connectivity of phylogenetic composition has been shown; however, the functional vertical connectivity of microbial communities has not yet been explored in detail. We investigated protein and taxa profiles of both free-living and particle-attached microbial communities from the surface to 3000 m depth using a combined metaproteomic and 16S rRNA amplicon sequencing approach. A clear compositional and functional vertical connectivity of microbial communities was observed throughout the water column with Oceanospirillales, Alteromonadales, and Rhodobacterales as key taxa. The surface-derived particle-associated microbes increased the expression of proteins involved in basic metabolism, organic matter processing, and environmental stress response in deep waters. This study highlights the functional vertical connectivity between surface and deep-sea microbial communities via sinking particles and reveals that a considerable proportion of the deep-sea microbes might originate from surface waters and have a major impact on the biogeochemical cycles in the deep sea.

Development of autoimmune thyroid disease after COVID-19 infection: case report.

Background: SARS-CoV-2 could trigger multiple immune responses, leading to several autoimmune diseases, including thyroid diseases. Many cases of thyroid diseases caused by COVID-19 infection have been reported. Here, we describe the disease development of patients with autoimmune thyroid disease after COVID-19 infection. Methods: The clinical characteristics, diagnosis and treatment of five different patients with autoimmune thyroid disease after COVID-19 infection were reported. Results: Female patients with primary autoimmune thyroid disease which have been stable for many years were reported. One month after COVID-19 infection, the disease has undergone different evolution. Case 1, a patient with history of long-term stable Hashimoto's thyroiditis, suddenly suffered from Graves disease after COVID-19 infection. Case 2, a patient with history of long-term stable Hashimoto's thyroiditis with thyroid nodules, suddenly suffered from Graves disease after infection. Case 3, a patient with history of long-term stable Graves disease, suddenly suffered from worsening after infection. The above three cases showed thyroid-stimulating antibodies were enhanced. Case 4, a patient with history of previous hypothyroidism had an increase in thyroid-related antibody (TPOAb and TRAb) activity after infection, followed by a marked worsening of hypothyroidism. Case 5, a patient with no history of thyroid disease suddenly developed controllable "thyrotoxicosis" after infection, suggesting the diagnosis of painless thyroiditis. Conclusion: The five case reports show a different development of the primary autoimmune thyroid disease after COVID-19 infection. The change in the trend of thyroid disease is closely related to the immune response induced by SARS-CoV-2 infection.

Effect of fucoidan on gut microbiota and its clinical efficacy in Helicobacter pylori eradication: A randomized controlled trial.

OBJECTIVE: To assess the clinical efficacy of fucoidan-assisted standard quadruple therapy (SQT) in Helicobacter pylori (H. pylori) eradication and the improvement of gut microbiota. METHODS: An open-label randomized controlled trial was conducted at the Affiliated Hospital of Qingdao University in Shandong Province, China. Ninety patients who tested positive for H. pylori were randomized to the standard quadruple therapy (SQT) group (SQ), SQT + fucoidan combination group (SF), and fucoidan + sequential SQT group (FS), respectively. Stool samples were collected for gut microbiota composition at baseline and after treatment. RESULTS: After H. pylori eradication, the relative abundances of most conditional pathogens in the SQ decreased, while those of several beneficial bacteria increased or decreased (P < 0.05). In FS, the abundances of most beneficial bacteria increased gradually from baseline to week 12, while those of the conditional pathogens decreased (P < 0.05). The abundance of Bifidobacterium had a decreasing trend in SQ, but remained unchanged in SF and increased in FS (P < 0.05). The abundances of most beneficial bacteria were significantly higher in FS than in SQ and SF (P < 0.05). Addition of fucoidan enhanced symptom improvement during H. pylori eradication compared with SQT alone. CONCLUSIONS: Fucoidan considerably improved gut dysbiosis during SQT for H. pylori eradication. Gut microbiota can be maintained by the addition of fucoidan before eradication therapy with SQT rather than by concomitant addition with therapy. Fucoidan-assisted SQT could relieve gastrointestinal symptoms during H. pylori eradication.

Global analysis of the biosynthetic chemical space of marine prokaryotes.

BACKGROUND: Marine prokaryotes are a rich source of novel bioactive secondary metabolites for drug discovery. Recent genome mining studies have revealed their great potential to bio-synthesize novel secondary metabolites. However, the exact biosynthetic chemical space encoded by the marine prokaryotes has yet to be systematically evaluated. RESULTS: We first investigated the secondary metabolic potential of marine prokaryotes by analyzing the diversity and novelty of the biosynthetic gene clusters (BGCs) in 7541 prokaryotic genomes from cultivated and single cells, along with 26,363 newly assembled medium-to-high-quality genomes from marine environmental samples. To quantitatively evaluate the unexplored biosynthetic chemical space of marine prokaryotes, the clustering thresholds for constructing the biosynthetic gene cluster and molecular networks were optimized to reach a similar level of the chemical similarity between the gene cluster family (GCF)-encoded metabolites and molecular family (MF) scaffolds using the MIBiG database. The global genome mining analysis demonstrated that the predicted 70,011 BGCs were organized into 24,536 mostly new (99.5%) GCFs, while the reported marine prokaryotic natural products were only classified into 778 MFs at the optimized clustering thresholds. The number of MF scaffolds is only 3.2% of the number of GCF-encoded scaffolds, suggesting that at least 96.8% of the secondary metabolic potential in marine prokaryotes is untapped. The unexplored biosynthetic chemical space of marine prokaryotes was illustrated by the 88 potential novel antimicrobial peptides encoded by ribosomally synthesized and post-translationally modified peptide BGCs. Furthermore, a sea-water-derived Aquimarina strain was selected to illustrate the diverse biosynthetic chemical space through untargeted metabolomics and genomics approaches, which identified the potential biosynthetic pathways of a group of novel polyketides and two known compounds (didemnilactone B and macrolactin A 15-ketone). CONCLUSIONS: The present bioinformatics and cheminformatics analyses highlight the promising potential to explore the biosynthetic chemical diversity of marine prokaryotes and provide valuable knowledge for the targeted discovery and biosynthesis of novel marine prokaryotic natural products. Video Abstract.

Antipsychotic drugs induce vascular defects in hematopoietic organs.

Antipsychotic agents are clinically utilized to treat schizophrenia and other mental disorders. These drugs induce neurological and metabolic side effects, but their influence on blood vessels remains largely unknown. Here, we show that haloperidol, one of the most frequently prescribed antipsychotic agents, induces vascular defects in bone marrow. Acute haloperidol treatment results in vascular dilation that is specific to hematopoietic organs. This vessel dilation is associated with disruption of hematopoiesis and hematopoietic stem/progenitor cells (HSPCs), both of which are reversible after haloperidol withdrawal. Mechanistically, haloperidol treatment blocked the secretion of vascular endothelial growth factor A (VEGF-A) from HSPCs. Genetic blockade of VEGF-A secretion from hematopoietic cells or inhibition of VEGFR2 in endothelial cells result in similar vessel dilation in bone marrow during regeneration after irradiation and transplantation. Conversely, VEGF-A gain of function rescues the bone marrow vascular defects induced by haloperidol treatment and irradiation. Our work reveals an unknown effect of antipsychotic agents on the vasculature and hematopoiesis with potential implications for drug application in clinic.

Saccharina japonica fucan suppresses high fat diet-induced obesity and enriches fucoidan-degrading gut bacteria.

Low molecular weight seaweed polysaccharides exhibit promising potential as novel therapeutics for the prevention of obesity and gut microbiota dysbiosis. The interplay between polysaccharides and gut microbiota may play crucial roles in their anti-obesity effects, but is largely unknown, including the impact of polysaccharides on the composition of the gut microbiota with polysaccharide-degrading capacity. The primary structure of a 5.1 kDa fucan (J2H) from Saccharina japonica was characterized and oral administration of J2H effectively suppressed high-fat diet-induced obesity, blood glucose metabolic dysfunction, dyslipidemia, and gut microbiota dysbiosis. Furthermore, the Jensen-Shannon divergence analysis demonstrated that J2H enriched at least four gut bacterial species with fucoidan-degrading potential, including Bacteroides sartorii and Bacteroides acidifaciens. Our findings suggest that the low molecular weight S. japonica fucan, J2H, is a promising potential agent for obesity prevention and its enrichment of gut bacteria with fucoidan-degrading potential may play a vital role in the anti-obesity effects.

Metagenomic analysis reveals wide distribution of phototrophic bacteria in hydrothermal vents on the ultraslow-spreading Southwest Indian Ridge.

Deep-sea hydrothermal vents are known as chemosynthetic ecosystems. However, high temperature vents emit light that hypothetically can drive photosynthesis in this habitat. Metagenomic studies have sporadically reported the occurrence of phototrophic populations such as cyanobacteria in hydrothermal vents. To determine how geographically and taxonomically widespread phototrophs are in deep-sea hydrothermal vents, we collected samples from three niches in a hydrothermal vent on the Southwest Indian Ridge and carried out an integrated metagenomic analysis. We determined the typical community structures of microorganisms found in active venting fields and identified populations of known potential chlorophototrophs and retinalophototrophs. Complete chlorophyll biosynthetic pathways were identified in all samples. By contrast, proteorhodopsins were only found in active beehive smoker diffusers. Taxonomic groups possessing potential phototrophy dependent on semiconductors present in hydrothermal vents were also found in these samples. This systematic comparative metagenomic study reveals the widespread distribution of phototrophic bacteria in hydrothermal vent fields. Our results support the hypothesis that the ocean is a seed bank of diverse microorganisms. Geothermal vent light may provide energy and confer a competitive advantage on phototrophs to proliferate in hydrothermal vent ecosystems. Supplementary Information: The online version contains supplementary material available at 10.1007/s42995-021-00121-y.

Chemical composition and anti-hepatoma effect of Annona squamosa L. pericarp oil.

In this study, an optimal method used to extract Annona squamosa pericarp oil (ASPO) was established according to the response surface model. The yield of ASPO was 1.45%. 8 fatty acids were identified from ASPO by GC-MS. Among them, (9Z)-9-Octadecenoic acid was abundant and accounted for 49.65%. The anti-hepatoma activities of ASPO were investigated against SMMC-7721 cell line in vitro and H22 cell line in vivo. Proteins associated with apoptosis in tumour tissue were quantified by western blot assay. The result revealed that ASPO had significant anti-hepatoma activities with IC50 value of 15.96 µg/mL in vitro and tumour inhibition rate of 54.14% at 50 mg/kg dose in vivo. Protein analysis showed that ASPO activated apoptosis by down-regulating Bcl-2, up-regulating Bax, cleaving caspase 9, cleaving caspase 8 and cleaving caspase 3 proteins. The possible mechanisms of apoptosis induced by ASPO were related to Fas/FasL/caspase-8/caspase-3 and Bcl-2/bax/caspase-9/caspase-3 pathways.

Effects of Neutrophil Extracellular Traps in Patients With Septic Coagulopathy and Their Interaction With Autophagy.

Introduction: Neutrophil extracellular traps (NETs) act as a critical trigger of inflammation and coagulation. We hypothesized that NETs are associated with septic hypercoagulability. Materials and Methods: In total, 82 patients admitted with sepsis in the Department of Critical Care Medicine of Peking Union Medical College Hospital were enrolled between February 2017 and April 2018. Clinical and hematological parameters and thrombotic or hemorrhagic events were recorded. Blood samples were obtained to assess biomarkers of NET formation, including neutrophil elastase 2 (ELA2) and citrullinated histone H3, and endothelial-derived biomarker syndecan-1. Autophagy levels and their regulation pathway were also examined to explore their interaction with NETs. Result: Sepsis patients with disseminated intravascular coagulation (DIC) showed significantly higher levels of NET formation [ELA2, 1,247 (86-625) vs. 2,039 (1,544-2,534), p < 0.0001; H3, 140 (47-233) vs. 307 (199-415), p < 0.0001]. NET formation was independently associated with DIC risk [ELA2, OR 1.0028, 95% CI, 1.0010-1.0045; H3, OR 1.0104, 95% CI, 1.0032-1.0176] and mortality [ELA2, HR 1.0014, 95% CI, 1.0004-1.0024; H3, HR 1.0056, 95% CI, 1.0008-1.0115]. The area under the curve value for ELA2 in predicting DIC occurrence was 0.902 (95% CI, 0.816-0.957), and that of H3 was 0.870 (95% CI, 0.778-0.934). Furthermore, biomarkers of NET formation, endothelial cells, and autophagy exhibited a significant correlation [ELA2 and Syn (r = 0.5985, p < 0.0001), LC3B (r = -0.4224, p < 0.0001); H3 and Syn (r = 0.6383, p < 0.0001), LC3B (r = -0.3005, p = 0.0061)]. Conclusion: Increased NET formation is significantly associated with sepsis-induced DIC incidence and mortality in sepsis patients, revealing a significant relationship with the autophagy pathway. Clinical Trial Registration: chictr.org.cn, identifier ChiCTR-ROC-17010750.

An atlas of bacterial secondary metabolite biosynthesis gene clusters.

Bacterial secondary metabolites are rich sources of novel drug leads. The diversity of secondary metabolite biosynthetic gene clusters (BGCs) in genome-sequenced bacteria, which will provide crucial information for the efficient discovery of novel natural products, has not been systematically investigated. Here, the distribution and genetic diversity of BGCs in 10 121 prokaryotic genomes (across 68 phyla) were obtained from their PRISM4 outputs using a custom python script. A total of 18 043 BGCs are detected from 5743 genomes with non-ribosomal peptide synthetases (25.4%) and polyketides (15.9%) as the dominant classes of BGCs. Bacterial strains harbouring the largest number of BGCs are revealed and BGC count in strains of some genera vary greatly, suggesting the necessity of individually evaluating the secondary metabolism potential. Additional analysis against 102 strains of discovered bacterial genera with abundant amounts of BGCs confirms that Kutzneria, Kibdelosporangium, Moorea, Saccharothrix, Cystobacter, Archangium, Actinosynnema, Kitasatospora, and Nocardia, may also be important sources of natural products and worthy of priority investigation. Comparative analysis of BGCs within these genera indicates the great diversity and novelty of the BGCs. This study presents an atlas of bacterial secondary metabolite BGCs that provides a lot of key information for the targeted discovery of novel natural products.

Labeling of liver cells with CdSe/ZnS quantum dot-based fluorescence probe below freezing point.

In this paper, CdSe/ZnS quantum dots (QDs) with particle size of 5.5 ~ 9.3 nm were synthesized, and the fluorescence emission ranged from 545 ~ 616 nm. When the volume fraction of ethanol was 30%, the water-soluble QD dispersion system remained liquid under -20 °C freezing conditions, the fluorescence intensity increased with a decrease in temperature, and the quantum yield reached 79% at -20 °C. The endothelial cell adhesion molecule CD31 antibody (anti-CD31) was used as the primary antibody, QDs were coupled with IgG as the secondary antibody (QD-Ab), and effective labeling of hepatic sinusoid endothelial cells was achieved at -20 °C. Fluorescence imaging and flow cytometry analysis showed that the labeling efficiency was as high as 97%, indicating that QDs have an important application prospect in microscopic section tomography of the liver.

Reduced microbial stability in the active layer is associated with carbon loss under alpine permafrost degradation.

Permafrost degradation may induce soil carbon (C) loss, critical for global C cycling, and be mediated by microbes. Despite larger C stored within the active layer of permafrost regions, which are more affected by warming, and the critical roles of Qinghai-Tibet Plateau in C cycling, most previous studies focused on the permafrost layer and in high-latitude areas. We demonstrate in situ that permafrost degradation alters the diversity and potentially decreases the stability of active layer microbial communities. These changes are associated with soil C loss and potentially a positive C feedback. This study provides insights into microbial-mediated mechanisms responsible for C loss within the active layer in degraded permafrost, aiding in the modeling of C emission under future scenarios.

Metaproteomics reveals the molecular mechanism underlying bloom maintenance of a marine dinoflagellate under low ambient CO2 and inorganic nutrients.

Dinoflagellate blooming periods are paradoxically characterized by high biomass growth rate and low ambient dissolved CO2 and inorganic nutrients, however, the underlying mechanisms linking cell growth and nutrient acquisition are poorly understood. Here, we compared metaproteomes of non-bloom, mid-blooming and late-blooming cells of a marine dinoflagellate Prorocentrum donghaiense. Cell division, metabolism of carbon, nitrogen, phosphorus, lipid, porphyrin and chlorophyll were more active in blooming cells than in non-bloom cells. Up-regulation of carbonic anhydrase, ribulose-1,5-bisphosphate carboxylase/oxygenase II, and C4-cycle proteins enhanced CO2 assimilation of P. donghaiense. Proteins participating in external organic nutrient acquisition and conversion, such as transporters for fatty acids, peptides and amino acids, external- and internal-phosphomonoester hydrolase, and diverse peptidases and amino acid transaminases, exhibited higher expression in blooming cells relative to non-bloom cells. Interestingly, dissolved organic nitrogen (DON) such as urea and aspartate significantly down-regulated expression and activity of carbon assimilation proteins except for RuBisCO form II, suggesting that DON provided sufficient carbon source which reduced the need to concentrate internal CO2. This study demonstrates that coupling of efficient CO2 assimilation with DON utilization are essential for bloom maintenance of P. donghaiense, and future efforts should be devoted to dissolved organic nutrients for prevention and management of dinoflagelllate blooms.

Characterization and hypoglycemic effects of sulfated polysaccharides derived from brown seaweed Undaria pinnatifida.

The brown seaweed Undaria pinnatifida polysaccharides show various biological activities, but their hypoglycemic activity and the underlying mechanism remain unclear. Here, three fractions of sulfated polysaccharides Up-3, Up-4, and Up-5 were prepared by microwave-assisted extraction from U. pinnatifida. In vitro assays demonstrated that Up-3 and Up-4 had strong α-glucosidase inhibitory activity, and Up-3, Up-4, and Up-5 could improve the glucose uptake in insulin-resistant HepG2 cells without affecting their viability. In vivo studies indicated Up-3 and Up-4 markedly reduced postprandial blood glucose levels. Up-U (a mixture of Up-3, Up-4, and Up-5), reduced fasting blood glucose levels, increased glucose tolerance and alleviated insulin resistance in HFD/STZ-induced hyperglycemic mice. Histopathological observation and hepatic glycogen measurement showed that Up-U alleviated the damage of the pancreas islet cell, reduced hepatic steatosis, and promoted hepatic glycogen synthesis. These findings suggest that Up-U could alleviate postprandial and HFD/STZ-induced hyperglycemia and was a potential agent for diabetes treatment.

Multiplex and visual detection of African Swine Fever Virus (ASFV) based on Hive-Chip and direct loop-mediated isothermal amplification.

African swine fever is caused by African swine fever virus (ASFV), and has a mortality rate approaching 100%. It has already caused tremendous economy lost around the world. Without effective vaccine, rapid and accurate on-site detection plays an indispensable role in controlling outbreaks. Herein, by combining Hive-Chip and direct loop-mediated isothermal amplification (LAMP), we establish a multiplex and visual detection platform. LAMP primers targeting five ASFV genes (B646L, B962L, C717R, D1133L, and G1340L) were designed and pre-fixed in Hive-Chip. On-chip LAMP showed the limits of detection (LOD) of ASFV synthetic DNAs and mock samples are 30 and 50 copies per microliter, respectively, and there is no cross-reaction among the target genes. The overall performance of our platform is comparable to that of the commercial kits. From sample preparation to results readout, the entire process takes less than 70 min. Multiplex detection of real samples of ASFV and other swine viruses further demonstrates the high sensitivity and specificity of Hive-Chip. Overall, our platform provides a promising option for on-site, fast and accurate detection of ASFV.

Sargassum fusiforme Polysaccharides Prevent High-Fat Diet-Induced Early Fasting Hypoglycemia and Regulate the Gut Microbiota Composition.

A low fasting blood glucose level is a common symptom in diabetes patients and can be induced by high-fat diet (HFD) feeding at an early stage, which may play important roles in the development of diabetes, but has received little attention. In this study, five polysaccharides were prepared from Sargassumfusiforme and their effects on HFD-induced fasting hypoglycemia and gut microbiota dysbiosis were investigated. The results indicated that C57BL/6J male mice fed an HFD for 4 weeks developed severe hypoglycemia and four Sargassumfusiforme polysaccharides (SFPs), consisting of Sf-2, Sf-3, Sf-3-1, and Sf-A, significantly prevented early fasting hypoglycemia without inducing hyperglycemia. Sf-1 and Sf-A could also significantly prevent HFD-induced weight gain. Sf-2, Sf-3, Sf-3-1, and Sf-A mainly attenuated the HFD-induced decrease in Bacteroidetes, and all five SFPs had a considerable influence on the relative abundance of Oscillospira, Mucispirillum, and Clostridiales. Correlation analysis revealed that the fasting blood glucose level was associated with the relative abundance of Mucispinllum and Oscillospira. Receiver operating characteristic analysis indicated that Mucispinllum and Oscillospira exhibited good discriminatory power (AUC = 0.745-0.833) in the prediction of fasting hypoglycemia. Our findings highlight the novel application of SFPs (especially Sf-A) in glucose homeostasis and the potential roles of Mucispinllum and Oscillospira in the biological activity of SFPs.

Thiazolidin-2-cyanamides derivatives as novel potent Escherichia coli ß-glucuronidase inhibitors and their structure-inhibitory activity relationships.

Gut microbial ß-glucuronidases have the ability to deconjugate glucuronides of some drugs, thus have been considered as an important drug target to alleviate the drug metabolites-induced gastrointestinal toxicity. In this study, thiazolidin-2-cyanamide derivatives containing 5-phenyl-2-furan moiety (1-13) were evaluated for inhibitory activity against Escherichia coli ß-glucuronidase (EcGUS). All of them showed more potent inhibition than a commonly used positive control, d-saccharic acid 1,4-lactone, with the IC50 values ranging from 1.2 µM to 23.1 µM. Inhibition kinetics studies indicated that compound 1-3 were competitive type inhibitors for EcGUS. Molecular docking studies were performed and predicted the potential molecular determinants for their potent inhibitory effects towards EcGUS. Structure-inhibitory activity relationship study revealed that chloro substitution on the phenyl moiety was essential for EcGUS inhibition, which would help researchers to design and develop more effective thiazolidin-2-cyanamide type inhibitors against EcGUS.

Five new ent-kaurane diterpenes from Annona squamosa L. pericarps.

In the present study, five new ent-kaurane diterpenes including 4α-hydroxy-17,19-dinor-ent-kaurane-16-one (1), 4ß-hydroxy-16ß-H-18-nor-ent-kaurane-17-oic acid (2), 4ß,17-dihydroxy-16α-acetoxy-18-nor-ent-kaurane (3), Annosquamosin Z (4) and 16α-H-ent-kaurane-17,18-dioic acid, 17-methy ester (5) were isolated from Annona squamosa L. pericarp. The compounds were also evaluated for their cytotoxic activities against SMMC-7721 and HepG2 cell lines, among which compound 3 exhibited potent cytotoxicity with IC50 value of less than 20 µM.

Trapa natans pericarp extract ameliorates hyperglycemia and hyperlipidemia in type 2 diabetic mice

Abstract The pericarp of Trapa natans L., an annual aquatic floating herb belonging to Lythraceae family, is used as a folk medicine in China. In this study, extracts of Trapa natans pericarp were tested both in vitro and in vivo through a high-fat diet with a single medium dosage streptozotocin injection induced type 2 diabetic mice. Different solvent extracts of Trapa natans pericarp showed α-amylase and α-glucosidase inhibitory activity. After four weeks administration, the ethyl acetate extract of Trapa natans pericarp (50 and 100 mg/kg b.w.) reduced fasting blood glucose level, ameliorated oral glucose tolerance and insulin resistance, improved serum lipids alterations in type 2 diabetic mice as well. Additionally, ethyl acetate extract significantly elevated the insulin receptor substrate 1 and Akt serine/threonine kinase phosphorylation compared to diabetic group. HPLC-MS and HPLC-DAD analysis showed that the ethyl acetate extract was rich in hydrolysable tannins. Results support the notion that Trapa natans pericarp extract has a potential hypoglycemic activity.