Anomalous origin of the left suprarenal, inferior phrenic arteries and left ovarian artery in a human cadaver.

This report addresses three variants identified within a female cadaver. Specifically, these were an anomalous origin of the right suprarenal artery, an abnormal bilateral ovarian vein branch, and a arterial tortuosity of the left ovarian artery. Indeed, the cadaver evinced abnormal origins in the case of the middle suprarenal artery (MSA), right inferior phrenic artery (IPA), and the renal capsule artery (emanating from the right renal artery). The MSA and IPA shared a common trunk with the inferior suprarenal artery. It was additionally observed that the right ovarian vein anastomoses the branches from the right kidney posterior inferior along with those to the renal fat capsule. Abnormal origin was evident in the case of the left ovarian artery, and arterial tortuosity was apparent in the lower region of the vessels. This report addresses both the clinical import of these variations and their likely causes. In the subdiaphragmatic region, surgical success and prognosis may be impacted by such anomalies; accordingly surgeons must be aware of anatomical variants of the ovarian and suprarenal arteries.

Structure of the siphophage neck-Tail complex suggests that conserved tail tip proteins facilitate receptor binding and tail assembly.

Siphophages have a long, flexible, and noncontractile tail that connects to the capsid through a neck. The phage tail is essential for host cell recognition and virus-host cell interactions; moreover, it serves as a channel for genome delivery during infection. However, the in situ high-resolution structure of the neck-tail complex of siphophages remains unknown. Here, we present the structure of the siphophage lambda "wild type," the most widely used, laboratory-adapted fiberless mutant. The neck-tail complex comprises a channel formed by stacked 12-fold and hexameric rings and a 3-fold symmetrical tip. The interactions among DNA and a total of 246 tail protein molecules forming the tail and neck have been characterized. Structural comparisons of the tail tips, the most diversified region across the lambda and other long-tailed phages or tail-like machines, suggest that their tail tip contains conserved domains, which facilitate tail assembly, receptor binding, cell adsorption, and DNA retaining/releasing. These domains are distributed in different tail tip proteins in different phages or tail-like machines. The side tail fibers are not required for the phage particle to orient itself vertically to the surface of the host cell during attachment.

Correction: Hybrid lanthanide nanoparticles as a new class of binary contrast agents for in vivo T1/T2 dual-weighted MRI and synergistic tumor diagnosis.

Correction for 'Hybrid lanthanide nanoparticles as a new class of binary contrast agents for in vivo T1/T2 dual-weighted MRI and synergistic tumor diagnosis' by Zhigao Yi et al., J. Mater. Chem. B, 2016, 4, 2715-2722, https://doi.org/10.1039/C5TB02375K.

Asymmetric Structure of Podophage GP4 Reveals a Novel Architecture of Three Types of Tail Fibers.

Bacteriophage tail fibers (or called tail spikes) play a critical role in the early stage of infection by binding to the bacterial surface. Podophages with known structures usually possess one or two types of fibers. Here, we resolved an asymmetric structure of the podophage GP4 to near-atomic resolution by cryo-EM. Our structure revealed a symmetry-mismatch relationship between the components of the GP4 tail with previously unseen topologies. In detail, two dodecameric adaptors (adaptors I and II), a hexameric nozzle, and a tail needle form a conserved tail body connected to a dodecameric portal occupying a unique vertex of the icosahedral head. However, five chain-like extended fibers (fiber I) and five tulip-like short fibers (fiber II) are anchored to a 15-fold symmetric fiber-tail adaptor, encircling the adaptor I, and six bamboo-like trimeric fibers (fiber III) are connected to the nozzle. Five fibers I, each composed of five dimers of the protein gp80 linked by an elongated rope protein, are attached to the five edges of the tail vertex of the icosahedral head. In this study, we identified a new structure of the podophage with three types of tail fibers, and such phages with different types of fibers may have a broad host range and/or infect host cells with considerably high efficiency, providing evolutionary advantages in harsh environments.

In Situ Structures of the Ultra-Long Extended and Contracted Tail of Myoviridae Phage P1.

The Myoviridae phage tail is a common component of contractile injection systems (CISs), essential for exerting contractile function and facilitating membrane penetration of the inner tail tube. The near-atomic resolution structures of the Myoviridae tail have been extensively studied, but the dynamic conformational changes before and after contraction and the associated molecular mechanism are still unclear. Here, we present the extended and contracted intact tail-structures of Myoviridae phage P1 by cryo-EM. The ultra-long tail of P1, 2450 Å in length, consists of a neck, a tail terminator, 53 repeated tail sheath rings, 53 repeated tube rings, and a baseplate. The sheath of the contracted tail shrinks by approximately 55%, resulting in the separation of the inner rigid tail tube from the sheath. The extended and contracted tails were further resolved by local reconstruction at 3.3 Å and 3.9 Å resolutions, respectively, allowing us to build the atomic models of the tail terminator protein gp24, the tube protein BplB, and the sheath protein gp22 for the extended tail, and of the sheath protein gp22 for the contracted tail. Our atomic models reveal the complex interaction network in the ultra-long Myoviridae tail and the novel conformational changes of the tail sheath between extended and contracted states. Our structures provide insights into the contraction and stabilization mechanisms of the Myoviridae tail.

Assembly and Capsid Expansion Mechanism of Bacteriophage P22 Revealed by High-Resolution Cryo-EM Structures.

The formation of many double-stranded DNA viruses, such as herpesviruses and bacteriophages, begins with the scaffolding-protein-mediated assembly of the procapsid. Subsequently, the procapsid undergoes extensive structural rearrangement and expansion to become the mature capsid. Bacteriophage P22 is an established model system used to study virus maturation. Here, we report the cryo-electron microscopy structures of procapsid, empty procapsid, empty mature capsid, and mature capsid of phage P22 at resolutions of 2.6 Å, 3.9 Å, 2.8 Å, and 3.0 Å, respectively. The structure of the procapsid allowed us to build an accurate model of the coat protein gp5 and the C-terminal region of the scaffolding protein gp8. In addition, interactions among the gp5 subunits responsible for procapsid assembly and stabilization were identified. Two C-terminal α-helices of gp8 were observed to interact with the coat protein in the procapsid. The amino acid interactions between gp5 and gp8 in the procapsid were consistent with the results of previous biochemical studies involving mutant proteins. Our structures reveal hydrogen bonds and salt bridges between the gp5 subunits in the procapsid and the conformational changes of the gp5 domains involved in the closure of the local sixfold opening and a thinner capsid shell during capsid maturation.

A Capsid Structure of Ralstonia solanacearum podoviridae GP4 with a Triangulation Number T = 9.

GP4, a new Ralstonia solanacearum phage, is a short-tailed phage. Few structures of Ralstonia solanacearum phages have been resolved to near-atomic resolution until now. Here, we present a 3.7 Å resolution structure of the GP4 head by cryo-electron microscopy (cryo-EM). The GP4 head contains 540 copies of major capsid protein (MCP) gp2 and 540 copies of cement protein (CP) gp1 arranged in an icosahedral shell with a triangulation number T = 9. The structures of gp2 and gp1 show a canonical HK97-like fold and an Ig-like fold, respectively. The trimeric CPs stick on the surface of the head along the quasi-threefold axis of the icosahedron generating a sandwiched three-layer electrostatic complementary potential, thereby enhancing the head stability. The assembly pattern of the GP4 head provides a platform for the further exploration of the interaction between Ralstonia solanacearum and corresponding phages.

Viral Capsid and Polymerase in Reoviridae.

The members of the family Reoviridae (reoviruses) consist of 9-12 discrete double-stranded RNA (dsRNA) segments enclosed by single, double, or triple capsid layers. The outer capsid proteins of reoviruses exhibit the highest diversity in both sequence and structural organization. By contrast, the conserved RNA-dependent RNA polymerase (RdRp) structure in the conserved innermost shell in all reoviruses suggests that they share common transcriptional regulatory mechanisms. After reoviruses are delivered into the cytoplasm of a host cell, their inner capsid particles (ICPs) remain intact and serve as a stable nanoscale machine for RNA transcription and capping performed using enzymes in ICPs. Advances in cryo-electron microscopy have enabled the reconstruction at near-atomic resolution of not only the icosahedral capsid, including capping enzymes, but also the nonicosahedrally distributed complexes of RdRps within the capsid at different transcriptional stages. These near-atomic resolution structures allow us to visualize highly coordinated structural changes in the related enzymes, genomic RNA, and capsid protein during reovirus transcription. In addition, reoviruses encode their own enzymes for nascent RNA capping before RNA releasing from their ICPs.

Molecular mechanism of the spider toxin κ-LhTx-I acting on the bacterial voltage-gated sodium channel NaChBac.

The bacterial sodium channel NaChBac is the prokaryotic prototype for the eukaryotic NaV and CaV channels, which could be used as a relatively simple model to study their structure-function relationships. However, few modulators of NaChBac have been reported thus far, and the pharmacology of NaChBac remains to be investigated. In the present study, we show that the spider toxin κ-LhTx-1, an antagonist of the KV4 family potassium channels, potently inhibits NaChBac with an IC50 of 491.0 ± 61.7 nM. Kinetics analysis revealed that κ-LhTx-1 inhibits NaChBac by impeding the voltage-sensor activation. Site-directed mutagenesis confirmed that phenylalanine-103 (F103) in the S3-S4 extracellular loop of NaChBac was critical for interacting with κ-LhTx-1. Molecular docking predicts the binding interface between κ-LhTx-1 and NaChBac and highlights a dominant hydrophobic interaction between W27 in κ-LhTx-1 and F103 in NaChBac that stabilizes the interface. In contrast, κ-LhTx-1 showed weak activity on the mammalian NaV channels, with 10 µM toxin slightly inhibiting the peak currents of NaV1.2-1.9 subtypes. Taken together, our study shows that κ-LhTx-1 inhibits the bacterial sodium channel, NaChBac, using a voltage-sensor trapping mechanism similar to mammalian NaV site 4 toxins. κ-LhTx-1 could be used as a ligand to study the toxin-channel interactions in the native membrane environments, given that the NaChBac structure was successfully resolved in a nanodisc.

Structural insights into a spindle-shaped archaeal virus with a sevenfold symmetrical tail.

Archaeal viruses with a spindle-shaped virion are abundant and widespread in extremely diverse environments. However, efforts to obtain the high-resolution structure of a spindle-shaped virus have been unsuccessful. Here, we present the structure of SSV19, a spindle-shaped virus infecting the hyperthermophilic archaeon Sulfolobus sp. E11-6. Our near-atomic structure reveals an unusual sevenfold symmetrical virus tail consisting of the tailspike, nozzle, and adaptor proteins. The spindle-shaped capsid shell is formed by seven left-handed helical strands, constructed of the hydrophobic major capsid protein, emanating from the highly glycosylated tail assembly. Sliding between adjacent strands is responsible for the variation of a virion in size. Ultrathin sections of the SSV19-infected cells show that SSV19 virions adsorb to the host cell membrane through the tail after penetrating the S-layer. The tailspike harbors a putative endo-mannanase domain, which shares structural similarity to a Bacteroides thetaiotaomicro endo-mannanase. Molecules of glycerol dibiphytanyl glycerol tetraether lipid were observed in hydrophobic clefts between the tail and the capsid shell. The nozzle protein resembles the stem and clip domains of the portals of herpesviruses and bacteriophages, implying an evolutionary relationship among the archaeal, bacterial, and eukaryotic viruses.

Structural and functional analysis of a potent human neutralizing antibody against enterovirus A71.

Enterovirus A71 (EV-A71) causes major outbreaks of hand, foot, and mouth disease (HFMD) in many countries, most frequently affecting children, and a small proportion of cases may lead to death. Currently, no vaccine is available in most endemic regions, and no licenced treatments for EV-A71 infection are available. Here, we characterize a human monoclonal antibody (HuMAb), E1, by screening a Fab antibody phage library derived from patients who recovered from EV-A71 infection. E1 exhibits strong neutralizing activity against EV-A71 virus in cells. The cryo-electron microscopy (cryo-EM) structures of the EV-A71 virion in complex with E1 Fab fragments demonstrated that E1 recognized an epitope formed by residues in the BC and HI loops of VP1. In a mouse model, E1 effectively protected against lethal EV-A71 challenge in both prophylactic and therapeutic treatment. In particular, E1 significantly reduces virus titers and muscle damage. E1 might represent a potential adjunct to EV-A71 treatment.

Lidocaine Suppresses Gastric Cancer Development Through Circ_ANO5/miR-21-5p/LIFR Axis.

BACKGROUND: Lidocaine has been manifested to exert anti-tumor role in gastric cancer (GC) progression. However, the action mechanism by which Lidocaine functions in GC has not been fully elucidated. AIM: The study aimed to reveal the molecular mechanism of Lidocaine in GC progression. METHODS: Cell clonogenicity and viability were assessed by colony formation and methyl thiazolyl tetrazolium assays, respectively. Transwell assay was employed to detect cell migration and invasion. Flow cytometry was implemented to monitor cell apoptosis. Relative expression of circular RNA ANO5 (circ_ANO5), microRNA (miR)-21-5p and Leukemia inhibitory factor receptor (LIFR) was examined by quantitative reverse transcription-polymerase chain reaction. Western blot assay was performed to analyze the levels of LIFR and cell metastasis-related proteins. The target relationship between miR-21-5p and circ_ANO5 or LIFR was confirmed by dual-luciferase reporter assay. In addition, xenograft model was established to explore the role of Lidocaine in vivo. RESULTS: Lidocaine inhibited cell proliferation, migration and invasion, while promoted apoptosis of GC cells. Lidocaine upregulated circ_ANO5 and LIFR expression, but downregulated miR-21-5p expression in GC cells. Additionally, expression of circ_ANO5 and LIFR was decreased, while miR-21-5p expression was increased in GC cells. Circ_ANO5 depletion or miR-21-5p overexpression attenuated Lidocaine-induced anti-proliferative and anti-metastatic effects on GC cells. Circ_ANO5 could sponge miR-21-5p, and miR-21-5p targeted LIFR. Moreover, Lidocaine suppressed the tumor growth in vivo. CONCLUSION: Lidocaine might GC cell malignancy by modulating circ_ANO5/miR-21-5p/LIFR axis, highlighting a novel insight for GC treatment.

Structure of an Al64Cu22Co14 decagonal quasicrystal studied by Cs-corrected STEM.

During the last several decades, since the discovery of a decagonal quasicrystal, a 2 nm cluster model has been widely accepted as its basic quasi-unit-cell (QUC). Instead of the traditional 2 nm QUC, a 3.2 nm QUC is proposed in this paper. The 3.2 nm QUC can fill all the blank areas. The 3.2 nm QUC consists of 251 atoms. The element type and position of each atom are determined using high-angle annular detector dark-field (HAADF) images taken along three projection directions, i.e., one along the ten-fold symmetry and the other two along the two-fold symmetry with an intersection angle of 18 degrees. The proposed model opens an avenue for further investigation of the aperiodic atomic structure of other quasicrystals.

Structural changes in bacteriophage T7 upon receptor-induced genome ejection.

Many tailed bacteriophages assemble ejection proteins and a portal-tail complex at a unique vertex of the capsid. The ejection proteins form a transenvelope channel extending the portal-tail channel for the delivery of genomic DNA in cell infection. Here, we report the structure of the mature bacteriophage T7, including the ejection proteins, as well as the structures of the full and empty T7 particles in complex with their cell receptor lipopolysaccharide. Our near-atomic-resolution reconstruction shows that the ejection proteins in the mature T7 assemble into a core, which comprises a fourfold gene product 16 (gp16) ring, an eightfold gp15 ring, and a putative eightfold gp14 ring. The gp15 and gp16 are mainly composed of helix bundles, and gp16 harbors a lytic transglycosylase domain for degrading the bacterial peptidoglycan layer. When interacting with the lipopolysaccharide, the T7 tail nozzle opens. Six copies of gp14 anchor to the tail nozzle, extending the nozzle across the lipopolysaccharide lipid bilayer. The structures of gp15 and gp16 in the mature T7 suggest that they should undergo remarkable conformational changes to form the transenvelope channel. Hydrophobic α-helices were observed in gp16 but not in gp15, suggesting that gp15 forms the channel in the hydrophilic periplasm and gp16 forms the channel in the cytoplasmic membrane.

Development of magnetic particle-based chemiluminescence immunoassay for measurement of human procalcitonin in serum.

BACKGROUND: Serum procalcitonin (PCT) has been recognized as a primary biomarker in bacterial infections, and monitoring its concentration could help to evaluate the prognosis of sepsis and guide the antibiotic administration. We aimed to establish a fast and accurate immunoassay for PCT quantitation. METHODS: Our newly developed monoclonal antibodies (mAbs) against human PCT were preliminarily evaluated by enzyme-linked immunosorbent assay and then used to develop a chemiluminescence enzyme immunoassay (CLEIA). The proposed CLEIA was assessed in analytical performance and applied to measurement of serum PCT. RESULTS: mAb 2D3 and mAb 8F6 were selected as capture and detection antibody respectively, due to the highest sensitivity for PCT detection with no cross reaction to calcitonin gene-related peptides. The proposed CLEIA based on mAb pair of 2D3/8F6-AP was characterized for a working range from 0.03 to 100 µg/L. An excellent correlation was observed between our proposed assay and the VIDAS BRAHMS PCT assay (r: 0.9825). CONCLUSION: Our newly developed mAbs and CLEIA can serve as important diagnostic tools for measurement of human PCT in serum.

Low dose soft X-ray-controlled deep-tissue long-lasting NO release of persistent luminescence nanoplatform for gas-sensitized anticancer therapy.

Nitric oxide (NO)-based gas therapy is emerged as a new adjunct anti-tumor treatment method, which has triggered a great research interest. Nevertheless, due to the short half-life of NO gas in vivo, it is of significance to develop NO-gas based gasotransmitter with controllable NO release for deep-tissue anti-tumor therapy. Herein, a novel soft X-ray activated persistent luminescence nanotransducer is designed for controllable and long-lasting NO release and deep-tissue anti-cancer therapy by integrating ZnGa2O4:Mn (ZGO:Mn) nanoparticles with light-responsive NO donor (RBS). With the merits of the ultra-low dosage (down to 0.9 mGy) soft X-ray activated persistent luminescence from small sized ZGO:Mn, continuous NO release is achieved for about 40 min after stopping the irradiation of X-ray. Moreover, the green persistent luminescence can be renewably activated by in-situ soft X-ray irradiation, leading to the repeatable long-lasting NO release in deep tissue (up to 24 mm). And the designed NO-releasing platform presents efficient in vitro and in vivo anti-cancer therapy. Therefore, the designed persistent luminescence-based NO gasotransmitter provides a new NO-releasing strategy for depth-independent gas-sensitized therapeutic applications.

Structure of RdRps Within a Transcribing dsRNA Virus Provides Insights Into the Mechanisms of RNA Synthesis.

RNA-dependent RNA polymerases (RdRps) catalyze RNA synthesis of RNA viruses. During initiation of RNA synthesis, the RdRp catalyzes the formation of the first dinucleotide, acting as primer for subsequent processive RNA elongation. Here, we present the structure of the RdRp complexes in the dinucleotide primed state in situ within a transcribing cypovirus under near physiological conditions using cryo-electron microscopy. The 3' end of RNA templates, paired RNA dinucleotide primer, incoming nucleotide, and catalytic divalent cations in the RdRp were resolved at 3.8 Å resolution. The end of the RNA template and the dinucleotide is buttressed by the aromatic tyrosine in a loop from the RdRp bracelet domain. Our structure reveals the interactions between the nucleotide substrates and the conserved residues during the RdRp initiation, and the coordinated structural changes preceding the elongation stage. In addition, it provides the direct evidence for existence of the slow step of the dinucleotide primed state in the viral RdRp transcription.

Polydopamine coated multifunctional lanthanide theranostic agent for vascular malformation and tumor vessel imaging beyond 1500 nm and imaging-guided photothermal therapy.

The optical imaging guided tumor vessels and vascular malformation visualization by using the second near infrared emission beyond 1500 nm (NIR-II) is emerged as the next generation fluorescence imaging technique for early tumor diagnosis and identification of tumor-associated vascular features. On the other hand, developing theranostic probes for NIR-II imaging guided photothermal therapy (PTT) is of great significance, which is rarely explored. Herein, a high performance theranostic nanoplatform based on the core-shell structured NaLuF4 nanorods@polydopamine (denoted as NRs@PDA) by integrating the new advanced NIR-II imaging beyond 1500 nm with PTT function was developed for tumor-associated vascular malformation visualization and imaging-guided PTT. Methods: In this work, the hydrophilic NaLuF4 NRs@PDA therapeutic probe was synthesized by using a reverse microemulsion method. The crystal phase, morphology, emission spectra and photothermal performance of the synthesized samples were systematically characterized. The NIR-II optical imaging and photothermal properties were investigated by in vitro and in vivo experiments. Results: The NaLuF4 NRs@PDA therapeutic probe possessed efficient NIR-II emission centered at 1525 nm with high quantum yield (QY), good photo-stability and high biocompatibility. In vivo NIR-IIb imaging based on the designed probe can clearly visualize the whole-body vessel and brain vessel with high spatial resolution, especially tumor-associated vessels. In addition, in vitro and in vivo experiments also demonstrated that the designed NaLuF4 NRs@PDA probe possessed efficient photothermal conversion efficiency (40.18%) for PTT ablation of tumor. Conclusion: With the excellent NIR-II imaging ability and PTT of tumor, the designed theranostic nanoplatform successfully realize the simultaneous tumor vessel diagnosis and tumor therapy, which may provide the opportunity of designing new theranostic bioprobes with combination of the NIR-II optical imaging technique and PTT function for tumor diagnosis and therapy.