RNA genome packaging and capsid assembly of bluetongue virus visualized in host cells

Unlike those of double-stranded DNA (dsDNA), single-stranded DNA (ssDNA), and ssRNA viruses, the mechanism of genome packaging of dsRNA viruses is poorly understood. Here, we combined the techniques of high-resolution cryoelectron microscopy (cryo-EM), cellular cryoelectron tomography (cryo-ET), and structure-guided mutagenesis to investigate genome packaging and capsid assembly of bluetongue virus (BTV), a member of the Reoviridae family of dsRNA viruses. A total of eleven assembly states of BTV capsid were captured, with resolutions up to 2.8 Å, with most visualized in the host cytoplasm. ATPase VP6 was found underneath the vertices of capsid shell protein VP3 as an RNA-harboring pentamer, facilitating RNA packaging. RNA packaging expands the VP3 shell, which then engages middle- and outer-layer proteins to generate infectious virions. These revealed "duality" characteristics of the BTV assembly mechanism reconcile previous contradictory co-assembly and core-filling models and provide insights into the mysterious RNA packaging and capsid assembly of Reoviridae members and beyond.

AZGP1 Aggravates Macrophage M1 Polarization and Pyroptosis in Periodontitis

Periodontal tissue destruction in periodontitis is a consequence of the host inflammatory response to periodontal pathogens, which could be aggravated in the presence of type 2 diabetes mellitus (T2DM). Accumulating evidence highlights the intricate involvement of macrophage-mediated inflammation in the pathogenesis of periodontitis under both normal and T2DM conditions. However, the underlying mechanism remains elusive. Alpha-2-glycoprotein 1 (AZGP1), a glycoprotein featuring an MHC-I domain, has been implicated in both inflammation and metabolic disorders. In this study, we found that AZGP1 was primarily colocalized with macrophages in periodontitis tissues. AZGP1 was increased in periodontitis compared with controls, which was further elevated when accompanied by T2DM. Adeno-associated virus-mediated overexpression of Azgp1 in the periodontium significantly enhanced periodontal inflammation and alveolar bone loss, accompanied by elevated M1 macrophages and pyroptosis in murine models of periodontitis and T2DM-associated periodontitis, while Azgp1-/- mice exhibited opposite effects. In primary bone marrow-derived macrophages stimulated by lipopolysaccharide (LPS) or LPS and palmitic acid (PA), overexpression or knockout of Azgp1 markedly upregulated or suppressed, respectively, the expression of macrophage M1 markers and key components of the NLR Family Pyrin Domain Containing 3 (NLRP3)/caspase-1 signaling. Moreover, conditioned medium from Azgp1-overexpressed macrophages under LPS or LPS+PA stimulation induced higher inflammatory activation and lower osteogenic differentiation in human periodontal ligament stem cells (hPDLSCs). Furthermore, elevated M1 polarization and pyroptosis in macrophages and associated detrimental effects on hPDLSCs induced by Azgp1 overexpression could be rescued by NLRP3 or caspase-1 inhibition. Collectively, our study elucidated that AZGP1 could aggravate periodontitis by promoting macrophage M1 polarization and pyroptosis through the NLRP3/casapse-1 pathway, which was accentuated in T2DM-associated periodontitis. This finding deepens the understanding of AZGP1 in the pathogenesis of periodontitis and suggests AZGP1 as a crucial link mediating the adverse effects of diabetes on periodontal inflammation.

Bipoladien A, a Sesterterpenoid Containing an Undescribed 5/8/5/7 Carbon Skeleton from Bipolaris maydis

Bipoladiens A-E (1-5), five new ophiobolin-derived sesterterpenoids, and a known compound 6 (bipolaricin R) were isolated from the cultures of the phytopathogenic fungus Bipolaris maydis. Their structures and absolute configurations were elucidated based on comprehensive spectroscopic analyses, HRESIMS, electronic circular dichroism (ECD) calculations, and single-crystal X-ray diffraction analyses. Notably, compound 1 has an undescribed tetracyclic 5/8/5/7 fused carbon skeleton, and compound 2 possesses a rare multicyclic caged ring system. The biosynthetic pathway of 1 was proposed starting from 6 via a series of oxidation and cyclization reactions. Compound 6 showed excellent antiproliferation and apoptosis induction effects against A549 cell line. Additionally, compounds 5 and 6 exhibited noticeable antimicrobial ability against Bacillus cereus, Staphylococcus aureus, and Staphylococcus epidermidis. These findings not only developed the chemical and bioactivities diversities of ophiobolin-sesterterpenoid but also provided an idea to boost the application of natural products in the control of food pathogens.

Effects of unfolding treatment assisted glycation on the IgE/IgG binding capacity and antioxidant activity of ovomucoid

Ovomucoid is the immune-dominant allergen in the egg white of hens. Due to its structure based on nine disulfide bonds as well as its resistance to heat and enzymatic hydrolysis, the allergenicity of this food protein is difficult to decrease by technological processes. We sought to reduce its allergenicity through the Maillard reaction. The unfolding of ovomucoid with L-cysteine-mediated reduction was used to increase accessibility to conformational and linear epitopes by modifying the secondary and tertiary structures of the allergen. Glycation with different saccharides revealed the beneficial effect of maltose glycation on the IgG-binding capacity reduction. By determining the better glycation conditions of unfolded ovomucoid, we produced ovomucoid with reduced IgE binding capacity due to the glycation sites (K17, K112, K129, and K164) on epitopes. Moreover, after simulated infant and adult gastrointestinal digestion, the unfolded plus glycated ovomucoid showed higher ABTS˙+ scavenging activity, O2˙- scavenging activity, ˙OH scavenging activity, Fe2+ chelating activity, and a FRAP value; in particular, for ˙OH scavenging activity, there was a sharp increase of more than 100%.

[Application of bridging study design in preventive vaccine clinical trials]

Bridging study in vaccine clinical trials means a series of small-scale additional tests on the basis that the original safety and effectiveness of a vaccine have been confirmed in clinical trials, to prove that the characteristics of safety, immunogenicity and effectiveness of a vaccine are similar or consistent after component, population and immunization procedure change to other types which can extrapolate data from existing clinical trials. Compared with traditional vaccine clinical trials, bridging trials can promote the approval of vaccines to the market, accelerate the expansion of vaccine application, and promote the use of vaccines across regions and populations. In recent years, the application of bridge study design in vaccine clinical research has become more and more common. In order to better guide and promote the application of bridging trial design in the field of vaccine clinical research, we reviewed the design characteristics and application examples of bridging study design in vaccine clinical trials, and systematically elaborated the design ideas, key points and statistical evaluation methods of bridging study.

Aerobic glycolysis is the predominant means of glucose metabolism in neuronal somata, which protects against oxidative damage

It is generally thought that under basal conditions, neurons produce ATP mainly through mitochondrial oxidative phosphorylation (OXPHOS), and glycolytic activity only predominates when neurons are activated and need to meet higher energy demands. However, it remains unknown whether there are differences in glucose metabolism between neuronal somata and axon terminals. Here, we demonstrated that neuronal somata perform higher levels of aerobic glycolysis and lower levels of OXPHOS than terminals, both during basal and activated states. We found that the glycolytic enzyme pyruvate kinase 2 (PKM2) is localized predominantly in the somata rather than in the terminals. Deletion of Pkm2 in mice results in a switch from aerobic glycolysis to OXPHOS in neuronal somata, leading to oxidative damage and progressive loss of dopaminergic neurons. Our findings update the conventional view that neurons uniformly use OXPHOS under basal conditions and highlight the important role of somatic aerobic glycolysis in maintaining antioxidant capacity.

Protein target highlights in CASP15: Analysis of models by structure providers

We present an in-depth analysis of selected CASP15 targets, focusing on their biological and functional significance. The authors of the structures identify and discuss key protein features and evaluate how effectively these aspects were captured in the submitted predictions. While the overall ability to predict three-dimensional protein structures continues to impress, reproducing uncommon features not previously observed in experimental structures is still a challenge. Furthermore, instances with conformational flexibility and large multimeric complexes highlight the need for novel scoring strategies to better emphasize biologically relevant structural regions. Looking ahead, closer integration of computational and experimental techniques will play a key role in determining the next challenges to be unraveled in the field of structural molecular biology.

Arsenic Removal via the Biomineralization of Iron-Oxidizing Bacteria Pseudarthrobacter sp. Fe7

Arsenic (As) is a highly toxic metalloid, and its widespread contamination of water is a serious threat to human health. This study explored As removal using Fe(II)-oxidizing bacteria. The strain Fe7 isolated from iron mine soil was classified as the genus Pseudarthrobacter based on 16S rRNA gene sequence similarities and phylogenetic analyses. The strain Fe7 was identified as a strain of Gram-positive, rod-shaped, aerobic bacteria that can oxidize Fe(II) and produce iron mineral precipitates. X-ray diffraction, X-ray photoelectron spectroscopy, and energy-dispersive X-ray spectroscopy patterns showed that the iron mineral precipitates with poor crystallinity consisted of Fe(III) and numerous biological impurities. In the co-cultivation of the strain Fe7 with arsenite (As(III)), 100% of the total Fe and 99.9% of the total As were removed after 72 h. During the co-cultivation of the strain Fe7 with arsenate (As(V)), 98.4% of the total Fe and 96.9% of the total As were removed after 72 h. Additionally, the iron precipitates produced by the strain Fe7 removed 100% of the total As after 3 h in both the As(III) and As(V) pollution systems. Furthermore, enzyme activity experiments revealed that the strain Fe7 oxidized Fe(II) by producing extracellular enzymes. When 2% (v/v) extracellular enzyme liquid of the strain Fe7 was added to the As(III) or As(V) pollution system, the total As removal rates were 98.6% and 99.4%, respectively, after 2 h, which increased to 100% when 5% (v/v) and 10% (v/v) extracellular enzyme liquid of the strain Fe7 were, respectively, added to the As(III) and As(V) pollution systems. Therefore, iron biomineralized using a co-culture of the strain Fe7 and As, iron precipitates produced by the strain Fe7, and the extracellular enzymes of the strain Fe7 could remove As(III) and As(V) efficiently. This study provides new insights and strategies for the efficient remediation of arsenic pollution in aquatic environments.

Developing and evaluating an interprofessional shared decision-making care model for patients with perinatal depression in maternal care in urban China: a study protocol

BACKGROUND

The majority of patients with perinatal depression (PND) in China do not receive adequate treatment. As forming a therapeutic alliance with patients is crucial for depression treatment, shared decision-making (SDM) shows promise in promoting patients' uptake of evidence-based mental health services, but its impact on patient outcomes and implementation in real-world maternal care remain uncertain. Therefore, this study aims to develop and evaluate an interprofessional shared decision-making (IP-SDM) model for PND to enhance maternal mental health services.

METHODS

This study contains four research phases: feasibility testing (Phase 1), toolkit development (Phase 2), usability evaluation (Phase 3), and effectiveness evaluation (Phase 4). During the development stage, focus group interviews will be conducted with expectant and new mothers, as well as maternal care providers for feasibility testing. A toolkit, including a patient decision aid along with its user guide and training materials, will be developed based on the findings of Phase 1 and syntheses of up-to-date evidence and appraised by the Delphi method. Additionally, a cognitive task analysis will be used for assessing the usability of the toolkit. During the evaluation stage, a prospective randomized controlled trial embedded in a mixed methods design will be used to evaluate the effectiveness and cost-effectiveness of the IP-SDM care model. The study targets to recruit 410 expectant and new mothers who screen positive for depression. They will be randomly assigned to either an intervention group or a control group in a 1:1 ratio. Participants in the intervention group will receive decision aid, decision coaching, and clinical consultation, in addition to usual services, while the control group will receive usual services. The primary outcome is the quality of decision-making process, and the secondary outcomes include SDM, mental health service utilization and costs, depressive symptoms, and health-related quality of life. In-depth interviews will be used to explore the facilitating and hindering factors of SDM.

DISCUSSION

This study will develop an IP-SDM care model for PND that can be implemented in maternal care settings in China. This study will contribute to the understanding of how SDM impacts mental health outcomes and facilitate the integration of mental health services into maternal care.

TRIAL REGISTRATION

ChiCTR2300072559. Registered on 16 June 2023.

Microbial mechanisms to transform the super-trace element tellurium: a systematic review and discussion of nanoparticulate phases

Tellurium is a super-trace metalloid on Earth. Owing to its excellent physical and chemical properties, it is used in industries such as metallurgy and manufacturing, particularly of semiconductors and - more recently - solar panels. As the global demand for tellurium rises, environmental issues surrounding tellurium have recently aroused concern due to its high toxicity. The amount of tellurium released to the environment is increasing, and microorganisms play an important role in the biogeochemical cycling of environmental tellurium. This review focuses on novel developments on tellurium transformations driven by microbes and includes the following sections: (1) history and applications of tellurium; (2) toxicity of tellurium; (3) microbial detoxification mechanisms against soluble tellurium anions including uptake, efflux and methods of reduction, and reduced ability to cope with oxidation stress or repair damaged DNA; and (4) the characteristics and applications of tellurium nanoparticles (TeNPs) produced by microbes. This review raises the awareness of microorganisms in tellurium biogeochemical cycling and the growing applications for microbial tellurium nanoparticles.

A review on synthesis and antibacterial potential of bio-selenium nanoparticles in the food industry

Effective control of foodborne pathogen contamination is a significant challenge to the food industry, but the development of new antibacterial nanotechnologies offers new opportunities. Notably, selenium nanoparticles have been extensively studied and successfully applied in various food fields. Selenium nanoparticles act as food antibacterial agents with a number of benefits, including selenium as an essential trace element in food, prevention of drug resistance induction in foodborne pathogens, and improvement of shelf life and food storage conditions. Compared to physical and chemical methods, biogenic selenium nanoparticles (Bio-SeNPs) are safer and more multifunctional due to the bioactive molecules in Bio-SeNPs. This review includes a summarization of (1) biosynthesized of Bio-SeNPs from different sources (plant extracts, fungi and bacteria) and their antibacterial activity against various foodborne bacteria; (2) the antibacterial mechanisms of Bio-SeNPs, including penetration of cell wall, damage to cell membrane and contents leakage, inhibition of biofilm formation, and induction of oxidative stress; (3) the potential antibacterial applications of Bio-SeNPs as food packaging materials, food additives and fertilizers/feeds for crops and animals in the food industry; and (4) the cytotoxicity and animal toxicity of Bio-SeNPs. The related knowledge contributes to enhancing our understanding of Bio-SeNP applications and makes a valuable contribution to ensuring food safety.

Durability of neutralization against Omicron subvariants after vaccination and breakthrough infection

Booster immunizations and breakthrough infections can elicit severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron subvariant neutralizing activity. However, the durability of the neutralization response is unknown. We characterize the sensitivity of BA.1, BA.2, BA.2.75, BA.4/BA.5, BF.7, BQ.1.1, and XBB against neutralizing antibodies from vaccination, hybrid immunity, and breakthrough infections 4-6 months after vaccination and infection. We show that a two-dose CoronaVac or a third-dose ZF2001 booster elicits limited neutralization against Omicron subvariants 6 months after vaccination. Hybrid immunity as well as Delta, BA.1, and BA.2 breakthrough infections induce long-term persistence of the antibody response, and over 70% of sera neutralize BA.1, BA.2, BA.4/BA.5, and BF.7. However, BQ.1.1 and XBB, followed by BA.2.75, are more resistant to neutralization, with neutralizing titer reductions of ∼9- to 41-fold, ∼16- to 63-fold, and ∼4- to 25-fold, respectively. These data highlight additional vaccination in CoronaVac- or ZF2001-vaccinated individuals and provide insight into the durability of neutralization against Omicron subvariants.

The role of mitochondrial fission in intervertebral disc degeneration

Low back pain (LBP) is an extremely common disorder and is a major cause of disability globally. Intervertebral disc degeneration (IVDD) is the main contributor to LBP. Nevertheless, the specific mechanisms underlying the pathogenesis of IVDD remain unclear. Mitochondria are highly dynamic organelles that continuously undergo fusion and fission, known as mitochondrial dynamics. Accumulating evidence has revealed that aberrantly activated mitochondrial fission leads to mitochondrial fragmentation and dysfunction, which are involved in the development and progression of IVDD. To date, research into mitochondrial dynamics in IVDD is at an early stage. The present narrative review aims to summarize the most recent findings about the role of mitochondrial fission in the pathogenesis of IVDD.

Testing alternative hypotheses on the origin and speciation of Hawaiian katydids

Background

Hawaiian Islands offer a unique and dynamic evolutionary theatre for studying origin and speciation as the islands themselves sequentially formed by erupting undersea volcanos, which would subsequently become dormant and extinct. Such dynamics have not been used to resolve the controversy surrounding the origin and speciation of Hawaiian katydids in the genus Banza, whose ancestor could be from either the Old-World genera Ruspolia and Euconocephalus, or the New World Neoconocephalus. To address this question, we performed a chronophylogeographic analysis of Banza species together with close relatives from the Old and New Worlds.

Results

Based on extensive dated phylogeographic analyses of two mitochondrial genes (COX1 and CYTB), we show that our data are consistent with the interpretation that extant Banza species resulted from two colonization events, both by katydids from the Old World rather than from the New World. The first event was by an ancestral lineage of Euconocephalus about 6 million years ago (mya) after the formation of Nihoa about 7.3 mya, giving rise to B. nihoa. The second colonization event was by a sister lineage of Ruspolia dubia. The dating result suggests that this ancestral lineage first colonized an older island in the Hawaiian–Emperor seamount chain before the emergence of Hawaii Islands, but colonized Kauai after its emergence in 5.8 mya. This second colonization gave rise to the rest of the Banza species in two major lineages, one on the older northwestern islands, and the other on the newer southwestern islands.

Conclusion

Chronophylogeographic analyses with well-sampled taxa proved crucial for resolving phylogeographic controversies on the origin and evolution of species colonizing a new environment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12862-022-02037-2.

The role and mechanisms of long non-coding RNA LINC00662 in promoting the proliferation, migration, and angiogenesis of BGC-823 and HGC-27 cells and the subsequent effect on the progression of gastric cancer

A large body of evidence indicates that long non-coding ribonucleic acid (lncRNA) is widely involved in various cellular processes and tumor progression. LINC00662, an lncRNA, has been reported to play a role in lung cancer. However, the biological function of LINC00662 in gastric cancer (GC) has not yet been explored. This study aimed to investigate the role and mechanisms of LINC00662 in promoting the proliferation, migration, and angiogenesis of BGC-823 and HGC-27 cells and the subsequent effect on the progression of GC. The expression level of LINC00662 in GC tissues and cells was detected by quantitative reverse transcription polymerase chain reaction. Small interfering RNA was used to silence LINC00662 in BGC-823 and HGC-27 GC cells in vitro for an MTT assay, a colony formation assay, and a transwell assay to determine cell proliferation and invasion ability. LINC00662-silenced BGC-823 and HGC-27 cells were also injected into zebrafish to detect the proliferation and invasion ability of the cells. Co-cultures in vitro of human umbilical vein endothelial cells (HUVECs) with silenced LINC00662 and in vivo experiments were also performed. The upregulation of LINC00662 was observed in GC tissues and cell lines. Functional studies in vitro showed that knocking down LINC00662 inhibited the proliferation and invasion of GC cells. In vivo experiments in zebrafish also confirmed that knocked-down LINC00662 inhibited the proliferation and invasion of GC cells, and in vitro angiogenesis experiments showed that the supernatant of GC with knocked-down LINC00662 inhibited the angiogenesis of HUVECs. LINC00662 promoted the proliferation, invasion, and migration of GC cells and promoted angiogenesis. These findings suggest that LINC00662 may be a potential therapeutic target for GC.

Structures and comparison of endogenous 2-oxoglutarate and pyruvate dehydrogenase complexes from bovine kidney

The α-keto acid dehydrogenase complex family catalyzes the essential oxidative decarboxylation of α-keto acids to yield acyl-CoA and NADH. Despite performing the same overarching reaction, members of the family have different component structures and structural organization between each other and across phylogenetic species. While native structures of α-keto acid dehydrogenase complexes from bacteria and fungi became available recently, the atomic structure and organization of their mammalian counterparts in native states remain unknown. Here, we report the cryo-electron microscopy structures of the endogenous cubic 2-oxoglutarate dehydrogenase complex (OGDC) and icosahedral pyruvate dehydrogenase complex (PDC) cores from bovine kidney determined at resolutions of 3.5 Å and 3.8 Å, respectively. The structures of multiple proteins were reconstructed from a single lysate sample, allowing direct structural comparison without the concerns of differences arising from sample preparation and structure determination. Although native and recombinant E2 core scaffold structures are similar, the native structures are decorated with their peripheral E1 and E3 subunits. Asymmetric sub-particle reconstructions support heterogeneity in the arrangements of these peripheral subunits. In addition, despite sharing a similar monomeric fold, OGDC and PDC E2 cores have distinct interdomain and intertrimer interactions, which suggests a means of modulating self-assembly to mitigate heterologous binding between mismatched E2 species. The lipoyl moiety lies near a mobile gatekeeper within the interdomain active site of OGDC E2 and PDC E2. Analysis of the twofold related intertrimer interface identified secondary structural differences and chemical interactions between icosahedral and cubic geometries of the core. Taken together, our study provides a direct structural comparison of OGDC and PDC from the same source and offers new insights into determinants of interdomain interactions and of architecture diversity among α-keto acid dehydrogenase complexes.

Using cryoEM and cryoET to visualize membrane penetration of a non-enveloped virus

Key to cell entry by non-enveloped viruses is virus-cell interactions at the cell or endosomal membrane. Here, we detail our protocols to capture such interactions between non-enveloped virus bluetongue virus (BTV) and vesicular membrane by cryogenic electron microscopy (cryoEM) and tomography (cryoET). Key steps include virus isolation, liposome preparation, virus-liposome incubation and vitrification, cryoEM and cryoET imaging, data processing for 3D reconstruction, and subtomogram averaging. The protocols can be generally applicable to studies of cell entry by other non-enveloped viruses. For complete details on the use and execution of this protocol, please refer to Xia et al. (2021).

KCNQ1OT1 promotes genome-wide transposon repression by guiding RNA-DNA triplexes and HP1 binding

Transposon (de)repression and heterochromatin reorganization are dynamically regulated during cell fate determination and are hallmarks of cellular senescence. However, whether they are sequence specifically regulated remains unknown. Here we uncover that the KCNQ1OT1 lncRNA, by sequence-specific Hoogsteen base pairing with double-stranded genomic DNA via its repeat-rich region and binding to the heterochromatin protein HP1α, guides, induces and maintains epigenetic silencing at specific repetitive DNA elements. Repressing KCNQ1OT1 or deleting its repeat-rich region reduces DNA methylation and H3K9me3 on KCNQ1OT1-targeted transposons. Engineering a fusion KCNQ1OT1 with an ectopically targeting guiding triplex sequence induces de novo DNA methylation at the target site. Phenotypically, repressing KCNQ1OT1 induces senescence-associated heterochromatin foci, transposon activation and retrotransposition as well as cellular senescence, demonstrating an essential role of KCNQ1OT1 to safeguard against genome instability and senescence.

Effective and stable adsorptive removal of Cadmium(II) and Lead(II) using selenium nanoparticles modified by microbial SmtA metallothionein

Metallothionein SmtA-modified selenium nanoparticles (SmtA-SeNPs), efficient adsorbents for Cd(II) and Pb(II), were synthesized in the present work. The ligand, microbial SmtA protein, was synthesized using an engineered strain Escherichia coli, posing the benefits of simplicity, safety, and high production. SmtA-SeNPs were spheres with diameters between 68.1 and 122.4 nm, containing amino, hydroxyl, and sulfhydryl functional groups with negatively charged (pH > 5). SmtA-SeNPs displayed better adsorption performance than dissociative SmtA and SeNPs. The adsorption of Cd(II) and Pb(II) mainly depends on the electrostatic attractions and the metal chelation of abundant functional groups. The maximum adsorption capacity was 506.3 mg/g for Cd(II) and 346.7 mg/g for Pb(II), which were higher than the values of most nanoparticles. In addition, SmtA-SeNPs were immobilized with a membrane filter to produce a SmtA-SeNPs filter, and the percentage removal of Cd(II) and Pb(II) increased from 26.75% to 98.13% for Cd(II) and from 9.95% to 99.20% compared with the blank filter. Moreover, the SmtA-SeNPs filter was regenerated using subacid deionized water, and the filter exhibited a stable removal ratio of Cd(II) and Pb(II) in ten continuous cycles of Cd(II)- or Pb(II)-containing wastewater treatment. The residual amounts of Cd and Pb met national standard levels of wastewater discharge.

Green synthesis of biogenetic Te(0) nanoparticles by high tellurite tolerance fungus Mortierella sp. AB1 with antibacterial activity

Tellurite [Te(IV)] is a high-toxicity metalloid. In this study, a fungus with high Te(IV) resistance was isolated. Strain AB1 could efficiently reduce highly toxic Te(IV) to less toxic Te(0). The reduced products formed rod-shaped biogenetic Te(0) nanoparticles (Bio-TeNPs) intracellularly. Further TEM-element mapping, FTIR, and XPS analysis showed that the extracted Bio-TeNPs ranged from 100 to 500 nm and consisted of Te(0), proteins, lipids, aromatic compounds, and carbohydrates. Moreover, Bio-TeNPs exhibited excellent antibacterial ability against Shigella dysenteriae, Escherichia coli, Enterobacter sakazakii, and Salmonella typhimurium according to inhibition zone tests. Further growth and live/dead staining experiments showed that E. coli and S. typhimurium were significantly inhibited by Bio-TeNPs, and cells were broken or shriveled after treatment with Bio-TeNPs based on SEM observation. Additionally, the antioxidant and cytotoxicity tests showed that the Bio-TeNPs exhibited excellent antioxidant capacity with no cytotoxicity. All these results suggested that strain AB1 showed great potential in bioremediation and Bio-TeNPs were excellent antibacterial nanomaterials with no cytotoxicity.

Tetramethylpyrazine in Chinese baijiu: Presence, analysis, formation, and regulation

Traditional Chinese fermented baijiu is one of the six major distilled spirits consumed worldwide. It plays an important role in people's daily life and social interactions because of its taste, nutritional value, and various health functions. Tetramethylpyrazine (TMP), also known as ligustrazine, is not only an important compound related to the flavor of Chinese baijiu but also has special pharmacological effects. It gives the baijiu a nutty and baked aroma and provides baijiu with important health benefits. Recently, the nutritional, drinking, and health aspects of baijiu have attracted significant attention. Therefore, the study of TMP in baijiu is an important aspect of baijiu health research. This mini novel review summarizes the formation mechanism of TMP, along with the current research progress, analytical methods used, and regulation strategies associated with TMP in Chinese baijiu in recent years.

[Suppression of HMGB1 inhibits neuronal autophagy and apoptosis to improve neurological deficits in rats following intracerebral hemorrhage]

OBJECTIVE

To investigate the effect of suppressing high-mobility group box 1 (HMGB1) on neuronal autophagy and apoptosis in rats after intracerebral hemorrhage (ICH) in rats.

METHODS

Rat models of ICH induced by intracerebral striatum injection of 0.2 U/mL collagenase Ⅳ were treated with 1 mg/kg anti-HMGB1 mAb or a control anti-IgG mAb injected via the tail immediately and at 6 h after the operation (n=5). The rats in the sham-operated group (with intracranial injection of 2 μL normal saline) and ICH model group (n=5) were treated with PBS in the same manner after the operation. The neurological deficits of the rats were evaluated using modified neurological severity score (mNSS). TUNEL staining was used to detect apoptosis of the striatal neurons, and the expressions of HMGB1, autophagy-related proteins (Beclin-1, LC3-Ⅱ and LC3-Ⅰ) and apoptosis-related proteins (Bcl-2, Bax and cleaved caspase-3) in the brain tissues surrounding the hematoma were detected using Western blotting. The expression of HMGB1 in the striatum was detected by immunohistochemistry, and serum level of HMGB1 was detected with ELISA.

RESULTS

The rat models of ICH showed significantly increased mNSS (P < 0.05), which was markedly lowered after treatment with anti- HMGB1 mAb (P < 0.05). ICH caused a significant increase of apoptosis of the striatal neurons (P < 0.05), enhanced the expressions of beclin-1, LC3-Ⅱ, Bax and cleaved caspase-3 (P < 0.05), lowered the expressions of LC3-Ⅰ and Bcl-2 (P < 0.05), and increased the content of HMGB1 (P < 0.05). Treatment with anti-HMGB1 mAb obviously lowered the apoptosis rate of the striatal neurons (P < 0.05), decreased the expressions of Beclin-1, LC3-Ⅱ, Bax and cleaved caspase-3 (P < 0.05), increased the expressions of LC3-Ⅰ and Bcl-2 (P < 0.05), and reduced the content of HMGB1 in ICH rats (P < 0.05).

CONCLUSION

Down- regulation of HMGB1 by anti-HMGB1 improves neurological functions of rats after ICH possibly by inhibiting autophagy and apoptosis of the neurons.

P-380 Single-cell transcriptome analysis reveales that expression changes of the endometrium in repeated implantation failure are altered by HPV-mediated CXCL chemokine secretion

Study question

What are the mechanisms and molecular expression patterns of reduced endometrial receptivity in repeated implantation failure (RIF) after human papillomavirus (HPV) infection?

Summary answer

The single-cell transcriptomic analysis identifies the expression changes of endometrium in RIF via HPV-mediated CXCL chemokines secretion in single-cell resolution.

What is known already

Regardless of the advance of in vitro fertilization (IVF), RIF is still a formidable challenge for couples and physicians in clinical treatment. In infertile couples, a reduction in natural and assisted cumulative pregnancy rate and an increase in miscarriage rate are related to the HPV infection.

Study design, size, duration

Cross-sectional clinical studies with 322 infertile couples undergoing IVF were integrated to demonstrate the associations between HPV infection and reproductive outcomes (pregnancy rate and miscarriage). Descriptive analysis of single-cell transcriptome data of uteruses, and transcriptome profiles of mid-secretory endometrium from 16 healthy fertile women and 38 repeated IVF failure women were analyzed to identify the expression patterns of endometrium in RIF. In vitro assays were used to validate the expression patterns in endometrium.

Participants/materials, setting, methods

322 infertile couples, single-cell transcriptome data of uteruses (human and mouse), and transcriptome profiles of endometrium (16 normal vs. 38 RIF) were used to analyze the association between HPV infection and reduced endometrial receptivity. HPV genes (E1, E2, E4, and E5) were transfected into a human normal endometrial epithelial cell line (hEM3), and immunohistochemistry, Westerns, quantitative PCR were used to validate the changes of CXCL chemokines in the endometrium in vitro.

Main results and the role of chance

Integrated cross-sectional studies demonstrate that HPV+ women exhibit a decreased pregnancy rate (83.09%) as compared with HPV- women (55.17%, P &lt;0.001), and a higher miscarriage rate (62.5% vs. 16.7%, P &lt;0.001) and the relative risk of spontaneous abortion (odd ratio=2.84, P &lt;0.0001) were observed in HPV+ women. Transcriptome profiling analysis identified the enrichment of the processes related to viral protein interaction with cytokine and cytokine receptor and cytokine-cytokine receptor interaction, especially in the CXCL chemokine family. Further analysis of single-cell transcriptome demonstrated that the changed expression patterns were associated with endometrial epithelial cells and immune cells, including macrophage dendritic cells, monocytes, and granulocytes. Moreover, in vitro assays validated the HPV-mediated CXCL chemokines secretion, which played the role in recruiting immune cells.

Limitations, reasons for caution

The current findings are based on the single-cell profiling analysis in normal endometrium. In addition, the in vivo response of the HPV infection may differ from the in vitro assay, which should be validated in the HPV infection couples.

Wider implications of the findings

Our study demonstrated the expression changes of endometrium in RIF via HPV-mediated CXCL chemokines secretion, which provided insight into the mechanisms of HPV-induced reduced endometrial receptivity in single-cell resolution.

Trial registration number

not applicable

Identification of a Novel Chromate and Selenite Reductase FesR in Alishewanella sp. WH16-1

A ferredoxin protein (AAY72_06850, named FesR) was identified to associate with chromate [Cr(VI)] resistance in Alishewanella sp. WH16-1. FesR and its similar proteins were phylogenetically separated from other reductase families. Unlike the reported Cr(VI) and selenite [Se(IV)] reductases, two 4Fe-4S clusters and one flavin adenine dinucleotide (FAD) -binding domain were found in the FesR sequence. The experiment in vivo showed that the mutant strain ΔfesR had lost partial Cr(VI) and Se(IV) reduction capacities compared to the wild-type and complemented strains. Furthermore, overexpression in Escherichia coli and enzymatic tests in vitro showed FesR were involved in Cr(VI) and Se(IV) reduction. 4Fe-4S cluster in purified FesR was detected by ultraviolet-visible spectrum (UV-VIS) and Electron Paramagnetic Resonance (EPR). The Km values of FesR for Cr(VI) and Se(IV) reduction were 1682.0 ± 126.2 and 1164.0 ± 89.4 μmol/L, and the Vmax values for Cr(VI) and Se(IV) reduction were 4.1 ± 0.1 and 9.4 ± 0.3 μmol min^–1 mg^–1, respectively. Additionally, site-directed mutagenesis and redox potential analyses showed that 4Fe-4S clusters were essential to FesR, and FAD could enhance the enzyme efficiencies of FesR as intracellular electron transporters. To the best of our knowledge, FesR is a novel Cr(VI) and Se(IV) reductase.

Discrimination and structural validity evaluation of Zung self-rating depression scale for pregnant women in China

PURPOSE

The applicability of the Zung self-rating depression scale (SDS) in pregnancy is unknown. We aimed to identify redundant items and evaluate the Zung SDS's structural validity.

METHOD

Two samples of pregnant women were invited from two districts in Shanghai (Yangpu sample, n = 6468 and Huangpu sample, n = 402). The Yangpu sample was randomly split into YGroup1/2/3. Item's properties were evaluated via the item response theory in YGroup1. Exploratory and confirmatory factor analyses were correspondingly executed in YGroup2 and YGroup3. Those items with discrimination parameter (α) lower than 0.65 or factor loading smaller than 0.4 were deleted from the scale. The final structure was validated in the Huangpu sample.

RESULTS

Items 4 (sleep), 7 (weight loss), 8 (constipation) and 9 (tachyarrhythmia) exhibited low discrimination power. Items 2 (diurnal variation), 5 (appetite), 10 (fatigue) and 19 (suicide idea) made a low contribution to all factors. A three-factor model was eventually constructed as cognitive (Items 14, 16, 17, 18 and 20), psychomotor (Items 6, 11 and 12) and affective (Items 1, 3, 13 and 15).

CONCLUSION

The Zung SDS needs modification before applied to pregnant women in China. The items describing the overlap symptoms of the physical change in pregnancy and mood disorder should be deleted.

Bluetongue virus capsid protein VP5 perforates membranes at low endosomal pH during viral entry

Bluetongue virus (BTV) is a non-enveloped virus and causes substantial morbidity and mortality in ruminants such as sheep. Fashioning a receptor-binding protein (VP2) and a membrane penetration protein (VP5) on the surface, BTV releases its genome-containing core (VP3 and VP7) into the host cell cytosol after perforation of the endosomal membrane. Unlike enveloped ones, the entry mechanisms of non-enveloped viruses into host cells remain poorly understood. Here we applied single-particle cryo-electron microscopy, cryo-electron tomography and structure-guided functional assays to characterize intermediate states of BTV cell entry in endosomes. Four structures of BTV at the resolution range of 3.4-3.9 Å show the different stages of structural rearrangement of capsid proteins on exposure to low pH, including conformational changes of VP5, stepwise detachment of VP2 and a small shift of VP7. In detail, sensing of the low-pH condition by the VP5 anchor domain triggers three major VP5 actions: projecting the hidden dagger domain, converting a surface loop to a protonated β-hairpin that anchors VP5 to the core and stepwise refolding of the unfurling domains into a six-helix stalk. Cryo-electron tomography structures of BTV interacting with liposomes show a length decrease of the VP5 stalk from 19.5 to 15.5 nm after its insertion into the membrane. Our structures, functional assays and structure-guided mutagenesis experiments combined indicate that this stalk, along with dagger domain and the WHXL motif, creates a single pore through the endosomal membrane that enables the viral core to enter the cytosol. Our study unveils the detailed mechanisms of BTV membrane penetration and showcases general methods to study cell entry of other non-enveloped viruses.

Assessing the rate of aging to monitor aging itself

Healthy aging is the prime goal of aging research and interventions. Healthy aging or not can be quantified by biological aging rates estimated by aging clocks. Generation and accumulation of large scale high-dimensional biological data together with maturation of artificial intelligence among other machine learning techniques, have enabled and spurred the rapid development of various aging rate estimators (aging clocks). Here we review the data sources and compare the algorithms of recent human aging clocks, and the applications of these clocks in both researches and daily life. We envision that not only more and multiscale data on cross-sectional data will add momentum to the aging clock development, new longitudinal and interventional data will further raise the aging clock development to the next level to be trained by true biological age such as morbidity and mortality age.

USP31 acetylation at Lys1264 is essential for its activity and cervical cancer cell growth

Ubiquitin-specific protease 31 (USP31) is a member of deubiquitinase family that is involved in nuclear factor-κB activation and sarcomagenesis. However, little is known about posttranslational modification in the regulation of its activity and cervical cancer cell growth. In our study, we found that the Lys1264 residue of USP31 can be modified with an acetyl group by high-resolution mass spectrometry in HeLa cell line, and site-specific mutagenesis can significantly increase USP31 ubiquitin hydrolase activity and decrease the expression of p65. When being transfected with a plasmid expressing mutated USP31, the number of cancer cells was significantly decreased. We also observed that mutated USP31 could promote apoptosis but not cell cycle by flow cytometer analysis. Overexpression of mutated USP31 could reverse the effect in USP31 knockdown cell line. To further investigate its activity in tumorigenesis, deacetylase sirtuin 1 (Sirt1) was shown to interact with USP31 by co-immunoprecipitation and blocking the function of Sirt1 by knockdown or the inhibitor nicotinamide could increase the acetylation of USP31. When Lys1264 of USP31 mutated, Sirt1 could not remove its acetylation and alter the expression level of p65. Finally, inhibition or knockdown of Sirt1 suppressed USP31 activity in HeLa cell line, leading to cisplatin-induced apoptosis resistance. Therefore, acetylation at Lys1264 suppresses USP31 activity and plays a protective role in cancer cell growth. Our study contributes to understanding the mechanism of USP31 activity regulation and its role in tumorigenesis.

Control of Streptomyces alfalfae XY25 T Over Clubroot Disease and Its Effect on Rhizosphere Microbial Community in Chinese Cabbage Field Trials

Clubroot caused by Plasmodiophora brassicae is one of the most destructive diseases in cruciferous crops. Streptomyces alfalfae XY25 ^T , a biological control agent, exhibited great ability to relieve clubroot disease, regulate rhizosphere bacterial and fungal communities in Chinese cabbage, and promote its growth in greenhouse. Therefore, field experiments were carried out to investigate the effects of S. alfalfae XY25 ^T on clubroot and rhizosphere microbial community in Chinese cabbage. Results showed that the control efficiency of clubroot by S. alfalfae XY25 ^T was 69.4%. Applying the agent can alleviate soil acidification; increase the contents of soil organic matter, available nitrogen, available phosphorus, and available potassium; and enhance activities of invertase, urease, catalase, and alkaline phosphatase. During Chinese cabbage growth, bacterial diversity decreased first and then increased, and fungal diversity decreased gradually after inoculation with S. alfalfae XY25 ^T . High-throughput sequencing analysis showed that the main bacterial phyla were Proteobacteria, Bacteroidetes, Acidobacteria, and Planctomycetes, and the major fungal phyla were Ascomycota and Basidiomycota in rhizosphere soil. The dominant bacterial genera were Flavobacterium, Candidatus, Pseudomonas, Stenotrophomonas, Sphingomonas, Flavisolibacter, and Gemmatimonbacteria with no significant difference in abundance, and the major fungal genera were Monographella, Aspergillus, Hypocreales, Chytridiaceae, Fusarium, Pleosporales, Agaricales, Mortierella, and Pleosporales. The significant differences were observed among Pleosporales, Basidiomycota, Colletotrichum, two strains attributed to Agaricales, and another two unidentified fungi by using S. alfalfae XY25 ^T . Moreover, quantitative real-time PCR results indicated that P. brassicae content was significantly decreased after the agent inoculation. In conclusion, S. alfalfae XY25 ^T can affect rhizosphere microbial communities; therefore, applying the agent is an effective approach to reduce the damage caused by clubroot.