Salivary carbonic anhydrase II in winged aphid morph facilitates plant infection by viruses.

Aphids are the most common insect vector transmitting hundreds of plant viruses. Aphid wing dimorphism (winged vs. wingless) not only showcases the phenotypic plasticity but also impacts virus transmission; however, the superiority of winged aphids in virus transmission over the wingless morph is not well understood. Here, we show that plant viruses were efficiently transmitted and highly infectious when associated with the winged morph of Myzus persicae and that a salivary protein contributed to this difference. The carbonic anhydrase II (CA-II) gene was identified by RNA-seq of salivary glands to have higher expression in the winged morph. Aphids secreted CA-II into the apoplastic region of plant cells, leading to elevated accumulation of H+. Apoplastic acidification further increased the activities of polygalacturonases, the cell wall homogalacturonan (HG)-modifying enzymes, promoting degradation of demethylesterified HGs. In response to apoplastic acidification, plants accelerated vesicle trafficking to enhance pectin transport and strengthen the cell wall, which also facilitated virus translocation from the endomembrane system to the apoplast. Secretion of a higher quantity of salivary CA-II by winged aphids promoted intercellular vesicle transport in the plant. The higher vesicle trafficking induced by winged aphids enhanced dispersal of virus particles from infected cells to neighboring cells, thus resulting in higher virus infection in plants relative to the wingless morph. These findings imply that the difference in the expression of salivary CA-II between winged and wingless morphs is correlated with the vector role of aphids during the posttransmission infection process, which influences the outcome of plant endurance of virus infection.

Organelle Proximity Analysis for Enhanced Quantification of Mitochondria-Endoplasmic Reticulum Interactions in Single Cells via Super-Resolution Microscopy.

Mitochondria (MT) and the endoplasmic reticulum (ER) maintain lipid and calcium homeostasis through membrane contacts, particularly MT-ER contacts (MERCs), spanning distances from 10 to 50 nm. However, the variation of different distance ranges and the metabolic factors influencing this variation remain poorly understood. This study employed microfluidic chip-based super-resolution microscopy in conjunction with a Moore-Neighbor tracing-incorporated organelle proximity analysis algorithm. This approach enabled precise three-dimensional localization of single-fluorescence protein molecules within narrow and irregular membrane proximities. It achieved lateral localization precision of less than 20 nm, resulting in a minimum MERC distance of approximately 8 nm in spatial and mean distances across multiple threshold ranges. Additionally, we demonstrated that the MERC distance variation was correlated with MT size rather than ER width. The proportion of each distance range varied significantly after the stimuli. Free cholesterol showed a negative correlation with various distances, while distances of 10-30 nm were associated with glucose, glutamine, and pyruvic acid. Furthermore, the 30-40 nm range was influenced by citric acid. These results underscore the role of advanced subcellular organelle analysis in elucidating the single-molecule behavior and organelle morphology in single-cell studies.

Multicompartmental Hydrogel Microspheres as a Tool for Multicomponent Analysis.

Developing advanced tools for multicomponent analysis is an open challenge in engineering and life science. Herein, multicompartmental hydrogel microspheres with multi-material compatibility and structural scalability are developed as a tool for multicomponent analysis at a single-particle level. Microfluidic technology endows particles with adjustable sizes and super-segmented layouts that can be used to load various analyte probes. In order to perform multicomponent analysis, these microspheres are structurally divided into identifier regions for indicating reading direction and analyte regions for detecting target molecules. The multiplex detection ability of these particles is demonstrated in microRNA bioassays with high specificity and sensitivity. The multi-target analysis is performed on a single-particle level, and the bioassay is free of conventional labeling interference. We expect these particles to reach their potential in clinical diagnostics.

Anatomical and Interpositional Bursa Preservation Showed Similar Improved Tendon to Bone Healing Compared With the Bursa Removal in a Rat Rotator Cuff Tear Model.

PURPOSE: To compare the effects of anatomical preservation (AP) and interpositional preservation (IP) of subacromial bursa tissue on tendon-to-bone healing in a rat model of rotator cuff tear. METHODS: In this study, 48 male Sprague-Dawley rats (average weight 283 g) underwent bilateral supraspinatus tendons severed by sharp incision and repaired immediately. The subacromial bursa tissues were completely removed in 16 rats, who served as the control (CON) group. The other 32 rats were randomly divided into 2 groups AP and IP between tendon and bone. Eight rats of each group were sacrificed for bilateral shoulders at 3 and 9 weeks after the operation, including 5 rats for biomechanical tests and 3 for histologic analysis. RESULTS: No significant differences in terms of biomechanical properties were observed among the groups 3 weeks after surgery. At 9 weeks, the maximum load and stiffness of the AP (32.95 ± 6.33 N, P = .029; 12.49 ± 3.17 N/mm, P < .001; respectively) and IP (33.58 ± 8.47 N, P = .015; 11.63 ± 2.84 N/mm, P = .010, respectively) groups were significantly superior to that of the CON group (26.59 ± 4.47 N; 8.42 ± 2.33 N/mm, respectively). More organized collagen and more mature tendon insertion were observed in AP and IP groups at the interface at 9 weeks, which means better tendon-to-bone healing compared with the CON group. CONCLUSIONS: The subacromial bursa plays a positive role in tendon-bone healing. Either anatomical preservation or interpositional preservation between tendon and bone can similarly facilitate the process of healing. CLINICAL RELEVANCE: Considering the additional surgical time and surgical manipulation, preserving the subacromial bursa at the anatomical position seems to be a better way to promote rotator cuff healing.

Cancellous bone should not be exposed during medialized rotator cuff repair based on bone-to-tendon healing in a rat mode.

PURPOSE: To compare the biological bone-to-tendon healing using three different medialized bone bed preparation techniques (i.e. cortical bone exposure, cancellous bone exposure, and no cartilage removal) in a rat model of medialized rotator cuff repair. METHODS: Twenty-one male Sprague-Dawley rats with 42 shoulders were subjected to bilateral supraspinatus tenotomy from the greater tuberosity. The rotator cuff was repaired using medialized anchoring with the cortical bone exposed, the cancellous bone exposed, or no cartilage removed. Four and three rats in each group were killed for biomechanical testing and histological evaluation, respectively, at postoperative 6 weeks. RESULTS: All rats survived until the end of the study, but one infected shoulder in the cancellous bone exposure group was excluded from further analysis. Compared with the cortical bone exposure and no cartilage removal groups, the rotator cuff healing of the cancellous bone exposure group showed significantly lower maximum load (cancellous bone exposure group: 26.2 ± 2.3 N, cortical bone exposure group: 37.6 ± 7.9 N, no cartilage removal group: 34.6 ± 7.2 N, P = 0.005 and 0.029) and less stiffness (cancellous bone exposure group: 10.5 ± 2.4 N/mm, cortical bone exposure group: 17.4 ± 6.7 N, no cartilage removal group: 16.0 ± 3.9 N, P = 0.015 and 0.050) at postoperative 6 weeks. In all three groups, the repaired supraspinatus tendon healed towards the original insertion rather than the medialized insertion. The cancellous bone exposure group showed inferior fibrocartilage formation and insertion healing. CONCLUSIONS: The medialized bone-to-tendon repair strategy does not guarantee complete histological healing, and the removal of excessive bony structure impairs bone-to-tendon healing. This study concludes that surgeons should not expose the cancellous bone during the medialized rotator cuff repair.

Absorbable suture knots on the supraspinatus tendon prevent adverse effects of nonabsorbable suture knots in a rat model.

PURPOSE: To compare the absorbable and nonabsorbable suture knots on the tendon on bone-to-tendon healing during the early phase in a rat rotator cuff tear (RCT) model. METHODS: Fifty-two male Sprague-Dawley rats (10 weeks old; mean weight, 380 g) were used in this study, and 51 of them were randomly assigned into three groups: absorbable suture group (ASG, n = 22), nonabsorbable suture group (NSG, n = 22), and sham surgery group (SSG, n = 7), and the remaining rat was used to take surgical pictures. Bilateral supraspinatus tendon tears were created and repaired immediately in ASG and NSG. Three rats from ASG and NSG were killed for Western blot and histological evaluation at 3 days, 1 week, and 4 weeks after surgery. At 4 weeks, four rats from each group were killed for biomechanical test, and three rats from SSG were used for histological evaluation. RESULTS: Absorbable suture knots on the tendon completely degraded at 4 weeks. However, nonabsorbable suture knots remained intact between the tendon and articular side. ASG showed a stronger inflammatory reaction at 3 days and 1 week, but a weaker reaction at 4 weeks as confirmed by gross observation and Western blot. Besides, ASG showed superior biomechanical properties in terms of maximum load to failure and stiffness at 4 weeks. Modified Bonar score revealed superior maturity for tissue healing in ASG to that in NSG at 4 weeks. Furthermore, inferior bone-to-tendon interface and weakest link formation were observed in NSG on histologic images. CONCLUSION: Absorbable suture knots on the tendon contributed to better mechanical properties compared with the nonabsorbable one after rotator cuff repair.

Research and Application of Energy-Efficient Management Approach for Wireless Sensor Networks.

Wireless sensor networks (WSNs) are widely used in industrial applications. However, many of them have limited lifetimes, which has been a considerable constraint on their widespread use. As a typical application of WSNs, distributed measurement of the electric field under high-voltage direct-current (HVDC) transmission lines also suffers from this issue. This paper first introduces the composition of the electric-field measurement system (EFMS) and its working principle. Considering the actual power supply of the system, this paper mainly introduces the composition of the wireless sensor node (WSND) and analyzes the power consumption and potential working state transformation of the WSND, together with a comprehensive study on parameters affecting the power consumption of the wireless communication unit. Moreover, an energy-efficient scheduling approach is proposed after specially designing a working sequence and the study on system parameters. The proposed approach is verified by experiments on not only the experimental line of the national HVDC test base, but also a commercial operation HVDC transmission line with the challenge of long endurance, which is considered in this paper with a new strategy. The results show that the proposed method can greatly extend the lifetime of the WSND.

Uncovering the Metabolic Mechanism of Salidroside Alleviating Microglial Hypoxia Inflammation Based on Microfluidic Chip-Mass Spectrometry.

Microglia are the main immune cells in the brain playing a critical role in neuroinflammation, and numerous pieces of evidence have proved that energy metabolism is closely associated with inflammation in activated microglia. Salidroside (Sal) isolated from Tibetan medicine Rhodiola crenulate can inhibit microglial hypoxia inflammation (HI). However, whether the inhibition is due to the intervening energy metabolic process in microglia is not clear. In this work, the hypoxic microenvironment of BV2 microglial cells was simulated using deferoxamine (DFO) in vitro and the change of cell metabolites (lactate, succinate, malate, and fumarate) was real-time online investigated based on a cell microfluidic chip-mass spectrometry (CM-MS) system. Meanwhile, for confirming the metabolic mechanism of BV2 cells under hypoxia, the level of HI-related factors (LDH, ROS, HIF-1α, NF-κB p65, TNF-α, IL-1ß, and IL-6) was detected by molecular biotechnology. Integration of the detected results revealed that DFO-induced BV2 cell HI was associated with the process of energy metabolism, in which cell energy metabolism changed from oxidative phosphorylation to glycolysis. Furthermore, administration of Sal treatment could effectively invert this change, and two metabolites of Sal were identified: tyrosol and 4-hydroxyphenylacetic acid. In general, we illustrated a new mechanism of Sal for reducing BV2 cell HI injury and presented a novel analysis strategy that opened a way for real-time online monitoring of the energy metabolic mechanism of the effect of drugs on cells and further provided a superior strategy to screen natural drug candidates for HI-related brain disease treatment.

The dynamic rotation axis of ulnohumeral joint during active flexion-extension: an in vivo 4-dimensional computed tomography analysis.

BACKGROUND: As the collateral ligament reconstruction becomes more common to perform, the knowledge between the collateral ligament reconstruction and the elbow rotation axis is still ambiguous. The purpose of this study was to investigate the location of the intersections between the elbow rotation axis and medial and lateral aspect of the humerus. METHODS: Four-dimensional computed tomography (4D CT) scan was designed to obtain the images from 8 participants. The instantaneous rotation axis was created according to the trochlea notch of the ulna in the Rapidform XO software. Then the intersections between the instantaneous rotation axis and the medial and lateral aspect of the humerus were identified in the Geomagic Wrap software. Landmark coordinate systems of the distal humerus was created. RESULT: The intersections in the medial aspect of the humerus were mostly located in the superior and posterior quadrant and showed the trend from anterior-superior to posterior-superior with the increment of the elbow flexion. The intersections in the lateral aspect of the humerus were mostly located in the middle half of the anterior quadrant and showed the trend from posterior-inferior to anterior-superior with the increment of the elbow flexion. CONCLUSION: There's no isometric point for medial collateral ligament (MCL) and lateral ulnar collateral ligament (LUCL) reconstruction. The isometric area for MCL reconstruction should be considered at the superior and posterior quadrant of the medial aspect of the humerus. The isometric area for LUCL reconstruction should be considered at the middle half of the anterior quadrant of the lateral aspect of the humerus. TRIAL REGISTRATION: This work was supported by the National Natural Science Foundation of China [ No.81911540488 ] in 07/01/2019.

Synthesis of metal ion-tolerant Mn-doped fluorescence silicon quantum dots with green emission and its application for selective imaging of ·OH in living cells.

Monitoring hydroxyl radical (·OH) in living cells remains a big challenge on account of its high reactivity and short half-life. In this work, we designed a fluorescent probe based on manganese-doped silicon quantum dots (Mn-SiQDs) for detecting and imaging of ·OH with good water solubility. The manganese was doped in its ethylene diamine tetra-acetic acid (EDTA) complex form and effectively improved the metal ion tolerance of fluorescence of SiQDs. And m-dihydroxybenzene was used as the reductant to extend the emission of SiQDs to the green region at 515 nm when the excitation wavelength was 424 nm. Basing on the fluorescence quenching of Mn-SiQDs, a linear response of ·OH was observed in the range 0.8-50 µM with a limit of detection (LOD) of 88.4 nM, which is lower than those reported with SiQDs. The interference from other ROS or RNS has been assessed and no impact was found. In fully aqueous systems, the Mn-SiQDs have been applied to monitor and image the endogenous ·OH in HeLa cells. Our work provided a new strategy for designing SiQDs with good biocompatibility, high selectivity and long monitoring wavelength. Synthesis of green-emitting silicon quantum dots with N-[3 -(trimethoxysilyl) propyl] ethylenediamine (DAMO), Ethylenediamine tetraacetic acid disodium salt dehydrate (EDTA-2Na·2H2O), manganese acetate tetrahydrate (Mn(CH3COO)2·4H20) and m-dihydroxybenzene. The green fluorescence of the silicon quantum dots can be selectively quenched by hydroxyl radicals.

Synthesis of sulfhydryl functionalized silicon quantum dots with high quantum yield for imaging of hypochlorite in cells and zebrafish.

Sulfhydryl functionalized silicon quantum dots (S-SiQDs) with a fluorescence quantum yield of 38.5% were synthesized using 3-mercaptopropyltrimethoxysilane (MPTMS) and m-phenylenediamine by a simple one-pot method. It is worth noting that by oxidizing the surface sulfhydryl groups and statically quenching, the fluorescence of S-SiQDs at 492 nm (excitation at 383 nm) can be selectively quenched by hypochlorite (ClO-) in a linear range of 0.05 to 1.8 µM with a low detection limit of 13 nM. The reaction was completed in 10 s with no interference from other ROS, metal ions, anions and reducing species. The silicon source containing sulfhydryl groups was used to synthesize silicon quantum dots for the first time, and the surface of the S-SiQDs was provided with sulfhydryl groups and reacted rapidly and sensitively with ClO-. The S-SiQDs have good photostability and biocompatibility, and can be further used for ClO- imaging in MCF-7 cells and zebrafish, showing great promise in biological imaging. The proposed assay demonstrates that 3-mercaptopropyltrimethoxysilane is a good choice to obtain a functionalized fluorescent nanoprobe for redox species.

Length Changes in the Interosseous Membrane During Forearm Rotation: A 3-Dimensional Study In Vivo.

PURPOSE: The length change of the interosseous membrane (IOM) during forearm rotation has not been fully studied. To explore the meaning of length change in the distal oblique band (DOB), the distal accessory band (DAB), and the proximal, middle, and distal parts of the central band (CBP, CBM, and CBD, respectively), we investigated the length change in these ligaments at maximum pronation, 45° of pronation, neutral position, 45° of supination, and maximum supination in vivo. METHODS: The images of the right forearms from 6 healthy volunteers were obtained by computed tomography scanning at the 5 above-mentioned rotation positions. We created 3-dimensional models of the radius and ulna, DOB, DAB, and central band based on the points of origin and insertion. Finally, the length of each ligament was estimated from the points of insertions and origins registered on the 3-dimensional models. RESULTS: The DAB and CBD lengths increased significantly from maximum pronation to 45° of pronation. The DOB length increased significantly from 45° of pronation to neutral position and decreased significantly from 45° of supination to maximum supination. The DAB and CBM lengths increased significantly from neutral position to 45° of supination. The DAB length decreased significantly from 45° of supination to maximum supination. For the CBP, no difference in length was observed during forearm rotation. CONCLUSIONS: The DOB becomes taut at neutral position, and the central band, especially the CBP, is nearly isometric. The findings indicate that the DOB may provide the primary stabilization of the distal radioulnar joint and that the central band is the key stabilizer during forearm rotation. CLINICAL RELEVANCE: Surgeons may pay attention to the DOB when a patient incurs a distal radioulnar joint injury, and the CBP may be the optimal location for IOM reconstruction.

Cubic spline-based depth-dependent localization of mitochondria-endoplasmic reticulum contacts by three-dimensional light-sheet super-resolution microscopy.

The contact distance between mitochondria (Mito) and endoplasmic reticulum (ER) has received considerable attention owing to their crucial function in maintaining lipid and calcium homeostasis. Herein, cubic spline algorithm-based depth-dependent fluorescence-free three-dimensional light-sheet super-resolution microscopy (3D LSRM) with dual-wavelength illumination sources was investigated to study the distance of Mito-ER contacts in various live cells. To detect wavelength-dependent scattering, 12 nm gold nanoparticles (AuNPs) and 20 nm silver nanoparticles (AgNPs) as fluorescence-free nanoprobes were conjugated with Mito and ER. The cubic spline algorithm-based method showed improved localization precision in lateral and axial directions compared with that for previously used least squares and least cubic algorithms. The cubic spline-based depth-dependent localization was applied to the spatial localization of nanoprobes in super-resolution images, in which the average distance of Mito and ER was 22.4 nm in HeLa cells, 22.2 nm in RAW264.7 macrophage cells, 21.9 nm in AGS cells, 21.4 nm in HT29 cells, and 21.3 nm in HEK293 cells. The distances were ∼12% larger than those previously determined by electron microscopy, which demonstrated that this method was accessible and reliable for studying the intracellular structures of various live cells at the subdiffraction limit resolution.

Forearm Interosseous Ligaments: Anatomical and Histological Analysis of the Proximal, Central, and Distal Bands.

PURPOSE: To characterize and compare the histological structure of the proximal, central, and distal bands of the interosseous membrane (IOM) of the human forearm in fresh-frozen specimens. METHODS: The IOMs from 16 fresh-frozen left forearm specimens were carefully dissected and examined. The footprint areas of the proximal, central, and distal IOM bands were measured in 6 specimens. The histological characteristics of the IOM bands were evaluated using hematoxylin-eosin and Masson trichrome staining protocols in 10 specimens as histological analysis necessitated an intact footprint. The footprint areas of the IOM were measured using an image processing program. The insertion complex was assessed using a light microscope. RESULTS: Histological assessment revealed that the IOM structure demonstrated similarities with ligament structure. The average footprint areas of the proximal, central, and distal bands at the radial site were 11.1 ± 0.8, 180.4 ± 30.4, and 10.7 ± 1.3 mm2, respectively. At the ulnar site, they were 11.0 ± 1.1, 171.8 ± 30.1, and 10.7 ± 1.2 mm2, respectively. The insertion complex of the IOM into the bone comprised 4 layers: (1) interwoven collagen, (2) oblique collagen, (3) mineralized fibrocartilage (tidemark), and (4) lamellar bone. The average tidemark zone thicknesses of the proximal, central, and distal bands were 20.1 ± 6.3, 107.8 ± 22.9, and 20.6 ± 4.7 µm, respectively at the radial site and 12.0 ± 4.5, 85.7 ± 23.2, and 13.5 ± 6.9 µm, respectively at the ulnar site. CONCLUSIONS: In this study, we confirm that the histological characteristics of the IOM are similar to those of ligaments. Compared with the proximal and distal bands, the central band has a greater footprint area and thicker tidemark zone. CLINICAL RELEVANCE: If surgical reconstruction is performed, the size and histological characteristics of the graft should be similar to those of the native ligaments.

Subacromial bursal preservation can enhance rotator cuff tendon regeneration: a comparative rat supraspinatus tendon defect model study.

BACKGROUND: The role of subacromial bursa in rotator cuff surgery is unknown. This study aimed to assess the subacromial bursa's role in the healing of supraspinatus tendon injury in a rat model. METHODS: Twenty-three male Sprague-Dawley rats (9 weeks old; weight, approximately 296 g) were used in this study. Three rats used as biomechanical study controls were killed at 12 weeks of age. A supraspinatus tendon defect was made bilaterally in 20 rats, whereas an additional subacromial bursa sectioning was performed on the left side. Six rats were killed for biomechanical testing and 4 were killed for histologic observation at 3 and 9 weeks, respectively. RESULTS: The regenerated tendon in the bursal preservation group showed significantly superior biomechanical properties in maximum load to failure at 3 and 9 weeks and stiffness at 9 weeks after surgery compared with the bursal removal group. The modified Bonar scale scores showed better regenerated supraspinatus tendons in the bursal preservation group. CONCLUSION: The present study found that the subacromial bursa plays an important role in rotator cuff regeneration in this rat supraspinatus injury model. Extensive bursectomy of the subacromial bursa may not be recommended in rotator cuff repair surgery, though future in vivo human studies are needed to confirm these observations.

The contact area of the radiocapitellar joint under pronation and supination with axial load using a 3-dimensional computed tomography: an in vivo study.

OBJECTIVE: To evaluate the contact area of the radiocapitellar joint with forearm pronation and supination under axial loading. MATERIALS AND METHODS: Six healthy volunteers (2 males and 4 females, mean age: 44.6 years) were included in the study. A computed tomography scan of the extended elbow joints was obtained at 4 positions of forearm: full pronation with or without load and full supination with or without load. Mimics, 3-matic Medical, Geomagic, and Photoshop were used to reconstruct 3-dimensional models. The contact area of the radiocapitellar joint was measured. Shifting of the center of the contact area of the radiocapitellar joint was measured. RESULTS: The axial load added 8.6% and 10.5% contact area to pronation and supination without load, respectively. From pronation without load, the center of contact area significantly shifted 2.4 ± 1.1 mm anteromedially to supination without load and shifted by 1.0 ± 0.5 mm to the center of the radial head compared with the pronation with load. The center of the contact area significantly shifted 2.4 ± 1.5 mm anteromedially from the pronation to the supination under loading. The contact area of the tuberosity anterior in the radial head significantly increased by 14% (without load) and 8% (with load) from pronation to supination. CONCLUSION: Axial loading increases the contact area of the radiocapitellar joint. The center of the contact area of the radiocapitellar joint changed according to loading and shifted to the anterior tuberosity of the radial head from forearm pronation to supination.

Topography of sensory receptors within the human glenohumeral joint capsule.

BACKGROUND AND HYPOTHESES: Sensory receptors in the joint capsule are critical for maintaining joint stability. However, the distribution of sensory receptors in the glenohumeral joint of the shoulder, including mechanoreceptors and free nerve endings, has not been described yet. This study aimed to describe the distributions of different sensory receptor subtypes in the glenohumeral joint capsule. Our hypotheses were as follows: (1) Sensory receptor subtypes would differ in density but follow a similar distribution pattern, and (2) the anterior capsule would have the highest density of sensory receptors. METHODS: Six glenohumeral joint capsules were harvested from the glenoid to the humeral attachment. The capsule was divided into 4 regions of interest (anterior, posterior, superior, and inferior) and analyzed using modified gold chloride stain. Sensory receptors as well as free nerve endings were identified and counted under a light microscope from sections of each region of interest. The density of each sensory receptor subtype was calculated relative to capsule volume. RESULTS: Sensory receptors were distributed in the glenohumeral joint capsule with free nerve endings. The anterior capsule exhibited the highest median density of all 4 sensory receptors examined, followed by the superior, inferior, and posterior capsules. The median densities of these sensory receptor subtypes also significantly differed (P = .007), with type I (Ruffini corpuscles) receptors having the highest density (2.97 U/cm3), followed by type IV (free nerve endings, 2.25 U/cm3), type II (Pacinian corpuscles, 1.40 U/cm3), and type III (Golgi corpuscles, 0.24 U/cm3) receptors. CONCLUSION: Sensory receptor subtypes are differentially expressed in the glenohumeral joint capsule, primarily type I and IV sensory receptors. The expression of sensory receptors was dominant in the anterior capsule, stressing the important role of proprioception feedback for joint stability. The surgical procedure for shoulder instability should consider the topography of sensory receptors to preserve or restore the proprioception of the shoulder joint.

Serratia symbiotica Enhances Fatty Acid Metabolism of Pea Aphid to Promote Host Development.

Bacterial symbionts associated with insects are often involved in host development and ecological adaptation. Serratia symbiotica, a common facultative endosymbiont harbored in pea aphids, improves host fitness and heat tolerance, but studies concerning the nutritional metabolism and impact on the aphid host associated with carrying Serratia are limited. In the current study, we showed that Serratia-infected aphids had a shorter nymphal developmental time and higher body weight than Serratia-free aphids when fed on detached leaves. Genes connecting to fatty acid biosynthesis and elongation were up-regulated in Serratia-infected aphids. Specifically, elevated expression of fatty acid synthase 1 (FASN1) and diacylglycerol-o-acyltransferase 2 (DGAT2) could result in accumulation of myristic acid, palmitic acid, linoleic acid, and arachidic acid in fat bodies. Impairing fatty acid synthesis in Serratia-infected pea aphids either by a pharmacological inhibitor or through silencing FASN1 and DGAT2 expression prolonged the nymphal growth period and decreased the aphid body weight. Conversely, supplementation of myristic acid (C14:0) to these aphids restored their normal development and weight gain. Our results indicated that Serratia promoted development and growth of its aphid host through enhancing fatty acid biosynthesis. Our discovery has shed more light on nutritional effects underlying the symbiosis between aphids and facultative endosymbionts.

Aphid-borne Viral Spread Is Enhanced by Virus-induced Accumulation of Plant Reactive Oxygen Species.

Most known plant viruses are spread from plant to plant by insect vectors. There is strong evidence that nonpersistently transmitted viruses manipulate the release of plant volatiles to attract insect vectors, thereby promoting virus spread. The mechanisms whereby aphid settling and feeding is altered on plants infected with these viruses, however, are unclear. Here we employed loss-of-function mutations in cucumber mosaic virus (CMV) and one of its host plants, tobacco (Nicotiana tabacum), to elucidate such mechanisms. We show that, relative to a CMVΔ2b strain with a deletion of the viral suppressor of RNAi 2b protein in CMV, plants infected with wild-type CMV produce higher concentrations of the reactive oxygen species (ROS) H2O2 in plant tissues. Aphids on wild-type CMV-infected plants engage in shorter probes, less phloem feeding, and exhibit other changes, as detected by electrical penetration graphing technology, relative to CMVΔ2b-infected plants. Therefore, the frequency of virus acquisition and the virus load per aphid were greater on CMV-infected plants than on CMVΔ2b-infected plants. Aphids also moved away from initial feeding sites more frequently on wild-type CMV infected versus CMVΔ2b-infected plants. The role of H2O2 in eliciting these effects on aphids was corroborated using healthy plants infused with H2O2 Finally, H2O2 levels were not elevated, and aphid behavior was unchanged, on CMV-infected RbohD-silenced tobacco plants, which are deficient in the induction of ROS production. These results suggest that CMV uses its viral suppressor of RNAi protein to increase plant ROS levels, thereby enhancing its acquisition and transmission by vector insects.

An aphid facultative symbiont suppresses plant defence by manipulating aphid gene expression in salivary glands.

Aphids often carry facultative symbionts to achieve diverse advantages. Serratia symbiotica, one of facultative endosymbionts, increases aphid tolerance to heat. However, whether it benefits aphid colonization on host plants is yet to be determined. In the current study, we found that Acyrthosiphon pisum harbouring S. symbiotica had longer feeding duration on Medicago truncatula than Serratia-free aphids. Contrastingly, Serratia-free aphids triggered higher accumulation of reactive oxygen species (ROS), jasmonic acid and salicylic acid responsive genes and cytosolic Ca2+ elevations than Serratia-infected aphids. Transcriptomic analysis of salivary glands indicated that a histidine-rich Ca2+ -binding protein-like gene (ApHRC) was expressed more highly in the salivary gland of Serratia-infected aphids than that of Serratia-free aphids. Once ApHRC was silenced, Serratia-infected aphids also displayed shorter phloem-feeding duration and caused Ca2+ elevation and ROS accumulation in plants. Our results suggest that ApHRC, a potential effector up-regulated by S. symbiotica in the salivary glands, impairs plant defence response by suppressing Ca2+ elevation and ROS accumulation, allowing colonization of aphids. This study has provided an insight into how facultative symbionts facilitate aphid colonization and adaptation to host plants.