Physiological and Transcriptional Analyses Provide Insight into Maintaining Ion Homeostasis of Sweet Sorghum under Salt Stress.

Sweet sorghum is an important bioenergy grass and valuable forage with a strong adaptability to saline environments. However, little is known about the mechanisms of sweet sorghum coping with ion toxicity under salt stresses. Here, we first evaluated the salt tolerance of a sweet sorghum cultivar "Lvjuren" and determined its ion accumulation traits under NaCl treatments; then, we explored key genes involved in Na+, Cl-, K+ and NO3- transport using transcriptome profiling and the qRT-PCR method. The results showed that growth and photosynthesis of sweet sorghum were unaffected by 50 and 100 mM NaCl treatments, indicative of a strong salt tolerance of this species. Under NaCl treatments, sweet sorghum could efficiently exclude Na+ from shoots and accumulate Cl- in leaf sheaths to avoid their overaccumulation in leaf blades; meanwhile, it possessed a prominent ability to sustain NO3- homeostasis in leaf blades. Transcriptome profiling identified several differentially expressed genes associated with Na+, Cl-, K+ and NO3- transport in roots, leaf sheaths and leaf blades after 200 mM NaCl treatment for 6 and 48 h. Moreover, transcriptome data and qRT-PCR results indicated that HKT1;5, CLCc and NPF7.3-1 should be key genes involved in Na+ retention in roots, Cl- accumulation in leaf sheaths and maintenance of NO3- homeostasis in leaf blades, respectively. Many TFs were also identified after NaCl treatment, which should play important regulatory roles in salt tolerance of sweet sorghum. In addition, GO analysis identified candidate genes involved in maintaining membrane stability and photosynthetic capacity under salt stresses. This work lays a preliminary foundation for clarifying the molecular basis underlying the adaptation of sweet sorghum to adverse environments.

[Development of Vital Signal Monitoring System Based on Accelerometer].

OBJECTIVE: Reduce the number of false alarms and measurement time caused by movement interference by the sync waveform of the movement. METHODS: Vital signal monitoring system based on motion sensor was developed, which collected and processed the vital signals continuously, optimized the features and results of vital signals and transmitted the vital signal results and alarms to the interface. RESULTS: The system was tested in many departments, such as digestive department, cardiology department, internal medicine department, hepatobiliary surgery department and emergency department, and the total collection time was 1 940 h. The number of false electrocardiograph (ECG) alarms decreased by 82.8%, and the proportion of correct alarms increased by 28%. The average measurement time of non-invasive blood pressure (NIBP) decreased by 16.1 s. The total number of false respiratory rate measurement decreased by 71.9%. CONCLUSIONS: False alarms and measurement failures can be avoided by the vital signal monitoring system based on accelerometer to reduce the alarm fatigue in clinic.

Topography of Reward and Aversion Encoding in the Mesolimbic Dopaminergic System.

Dopamine (DA) neurons in the VTA play essential roles in adaptive motivated behavior, which requires rapid discrimination between positive and negative motivational signature. However, the precise functional DA circuitry processing reward and aversive information remain elusive. Here, we report that the encoding of reward and aversion by the DA system in the NAc is tightly associated with its anatomical location. By recording the dynamics of DA release with genetically encoded fluorescent DA sensor using in vivo fiber photometry in freely moving male mice, we found that the DA-sensor signal in the dorsomedial NAc shell and dorsolateral NAc shell were increased during rewarding events and decreased during aversive noxious events. In contrast, the release of DA in the ventromedial NAc shell was increased by both rewarding and aversive stimuli, whereas the DA-sensor signal in the central ventromedial NAc shell and ventrolateral NAc shell showed complex dynamics. Furthermore, the activity of DA fibers in different subregions of NAc measured with calcium sensor largely recapitulated the changes of DA-sensor signal in response to rewarding and aversive stimuli. In addition, correlation analysis showed that the response magnitude of DA-sensor or fibers significantly changed along the DV axis of the NAc. These results revealed the distinct role of the mesolimbic DA system in different subregions of NAc in encoding value and salience.SIGNIFICANCE STATEMENT Adaptive motivated behavior requires rapid discrimination between favorable and harmful events and is dynamically modulated by dopamine (DA) neurons in the VTA. However, the precise relationship between distinct DA circuitry and reward/aversion signal encoding is not well understood. Here, by recording the dynamics of DA release and the activity of DA fibers in each subregion of the NAc using in vivo fiber photometry in freely moving animals, we found that the DA system in the dorsomedial/dorsolateral, ventromedial, and ventrolateral NAc shell plays different roles in encoding value and salience. These results extend our knowledge about how the mesolimbic DA system process motivational information at the circuitry level.

Chloride is beneficial for growth of the xerophyte Pugionium cornutum by enhancing osmotic adjustment capacity under salt and drought stresses.

Chloride (Cl-) is pervasive in saline soils, and research on its influence on plants has mainly focused on its role as an essential nutrient and its toxicity when excessive accumulation occurs. However, the possible functions of Cl- in plants adapting to abiotic stresses have not been well documented. Previous studies have shown that the salt tolerance of the xerophytic species Pugionium cornutum might be related to high Cl- accumulation. In this study, we investigated the Cl--tolerant characteristics and possible physiological functions of Cl- in the salt tolerance and drought resistance of P. cornutum. We found that P. cornutum can accumulate a large amount of Cl- in its shoots, facilitating osmotic adjustment and turgor generation under saline conditions. Application of DIDS (4,4´-diisothiocyanostilbene-2,2´-disulfonic acid), a blocker of anion channels, significantly inhibited Cl- uptake, and decreased both the Cl- content and its contribution to leaf osmotic adjustment, resulting in the exacerbation of growth inhibition in response to NaCl. Unlike glycophytes, P. cornutum was able to maintain NO3- homeostasis in its shoots when large amounts of Cl- were absorbed and accumulated. The addition of NaCl mitigated the deleterious effects of osmotic stress on P. cornutum because Cl- accumulation elicited a strong osmotic adjustment capacity. These findings suggest that P. cornutum is a Cl--tolerant species that can absorb and accumulate Cl- to improve growth under salt and drought stresses.

Nitrate transporter NPF7.3/NRT1.5 plays an essential role in regulating phosphate deficiency responses in Arabidopsis.

AtNPF7.3/AtNRT1.5, which is a nitrate transporter that drives root-to-shoot transport of NO3-, is also involved in modulating the response to K+ deprivation in Arabidopsis by affecting root development and K+ transport. However, whether NPF7.3/NRT1.5 functions in regulating plant responses to deficiencies of other nutrients remains unknown. In this study, we found that the expression of AtNPF7.3/AtNRT1.5 was predominant in the roots and was substantially induced by phosphate (Pi) starvation. The atnrt1.5 mutants displayed conspicuously longer primary roots along with a significantly reduced lateral root density under Pi-deficient conditions than did the wild-type plants, and these morphological differences in the roots were eliminated to a certain extent by the ethylene synthesis antagonist Co2+. Further analyses revealed that the expression of important Pi starvation-induced genes, which are directly involved in Pi transport, mobilization and distribution, were significantly higher in the atnrt1.5 mutants than that in the wild-type plants under Pi-starvation conditions; therefore, the atnrt1.5 mutants retained higher tissue Pi concentrations. Taken together, our results suggest that NPF7.3/NRT1.5 is an important component in the regulation of phosphate deficiency responses in Arabidopsis.

Identification of candidate genes related to salt tolerance of the secretohalophyte Atriplex canescens by transcriptomic analysis.

BACKGROUND: Atriplex canescens is a typical C4 secretohalophyte with salt bladders on the leaves. Accumulating excessive Na+ in tissues and salt bladders, maintaining intracellular K+ homeostasis and increasing leaf organic solutes are crucial for A. canescens survival in harsh saline environments, and enhanced photosynthetic activity and water balance promote its adaptation to salt. However, the molecular basis for these physiological mechanisms is poorly understood. Four-week-old A. canescens seedlings were treated with 100 mM NaCl for 6 and 24 h, and differentially expressed genes in leaves and roots were identified, respectively, with Illumina sequencing. RESULTS: In A. canescens treated with 100 mM NaCl, the transcripts of genes encoding transporters/channels for important nutrient elements, which affect growth under salinity, significantly increased, and genes involved in exclusion, uptake and vacuolar compartmentalization of Na+ in leaves might play vital roles in Na+ accumulation in salt bladders. Moreover, NaCl treatment upregulated the transcripts of key genes related to leaf organic osmolytes synthesis, which are conducive to osmotic adjustment. Correspondingly, aquaporin-encoding genes in leaves showed increased transcripts under NaCl treatment, which might facilitate water balance maintenance of A. canescens seedlings in a low water potential condition. Additionally, the transcripts of many genes involved in photosynthetic electron transport and the C4 pathway was rapidly induced, while other genes related to chlorophyll biosynthesis, electron transport and C3 carbon fixation were later upregulated by 100 mM NaCl. CONCLUSIONS: We identified many important candidate genes involved in the primary physiological mechanisms of A. canescens salt tolerance. This study provides excellent gene resources for genetic improvement of salt tolerance of important crops and forages.

Paeoniflorin suppresses TGF-ß mediated epithelial-mesenchymal transition in pulmonary fibrosis through a Smad-dependent pathway.

AIM: Paeoniflorin has shown to attenuate bleomycin-induced pulmonary fibrosis (PF) in mice. Because the epithelial-mesenchymal transition (EMT) in type 2 lung endothelial cells contributes to excessive fibroblasts and myofibroblasts during multiple fibrosis of tissues, we investigated the effects of paeoniflorin on TGF-ß mediated pulmonary EMT in bleomycin-induced PF mice. METHODS: PF was induced in mice by intratracheal instillation of bleomycin (5 mg/kg). The mice were orally treated with paeoniflorin or prednisone for 21 d. After the mice were sacrificed, lung tissues were collected for analysis. An in vitro EMT model was established in alveolar epithelial cells (A549 cells) incubated with TGF-ß1 (2 ng/mL). EMT identification and the expression of related proteins were performed using immunohistochemistry, transwell assay, ELISA, Western blot and RT-qPCR. RESULTS: In PF mice, paeoniflorin (50, 100 mg·kg(-1)·d(-1)) or prednisone (6 mg·kg(-1)·d(-1)) significantly decreased the expression of FSP-1 and α-SMA, and increased the expression of E-cadherin in lung tissues. In A549 cells, TGF-ß1 stimulation induced EMT, as shown by the changes in cell morphology, the increased cell migration, and the increased vimentin and α-SMA expression as well as type I and type III collagen levels, and by the decreased E-cadherin expression. In contrast, effects of paeoniflorin on EMT disappeared when the A549 cells were pretreated with TGF-ß1 for 24 h. TGF-ß1 stimulation markedly increased the expression of Snail and activated Smad2/3, Akt, ERK, JNK and p38 MAPK in A549 cells. Co-incubation with paeoniflorin (1-30 µmol/L) dose-dependently attenuated TGF-ß1-induced expression of Snail and activation of Smad2/3, but slightly affected TGF-ß1-induced activation of Akt, ERK, JNK and p38 MAPK. Moreover, paeoniflorin markedly increased Smad7 level, and decreased ALK5 level in A549 cells. CONCLUSION: Paeoniflorin suppresses the early stages of TGF-ß mediated EMT in alveolar epithelial cells, likely by decreasing the expression of the transcription factors Snail via a Smad-dependent pathway involving the up-regulation of Smad7.

[Effect of Madecassoside on Intestinal Mucosal Immunity in Collagen-Induced Arthritis Rats].

OBJECTIVE: To explore the changes of intestinal mucosal immunity in collagen-induced arthritis rats and the impact of madecassoside on these changes. METHODS: Collagen-induced arthritis was established in female Wistar rats. Treatment group was orally administrated madecassoside once daily for consecutive 21 days, while blank control and model groups were orally administered saline at the same volume. The concentrations of sIgA in small intestine content and IFN-γ in small intestinal tissue homogenate were determined by ELISA. The proportions of CD4+ T and CD8+ T in the epithelium and laminar propria of small intestine were detected by flow cytometry, and the ratios of CD4+/CD8+ were calculated. The relative expressions of CD80, CD86, IL-6, IL-12 and Foxp3 mRNA in the small intestine were determined by real-time PCR. RESULTS: Compared with blank control rats, the concentrations of sIgA in small intestine content and IFN-γ in small intestinal tissue homogenate from model rats were increased, the ratios of CD4+/CD8+ in the epithelium and laminar propria of small intestine were higher and the relative expressions of CD80, CD86, IL-6 and IL-12 mRNA in the small intestine were increased. Madecassoside treatment decreased the concentrations of sIgA in small intestine content and IFN-γ in small intestinal tissue, downregulated the ratios of CD4+/CD8+ in the epithelium and laminar propria and decreased the relative expressions of CD80, CD86, IL-6 and IL-12 mRNA, while upregulated the relative expression of Foxp3 mRNA in the small intestine. CONCLUSION: The intestinal mucosal immune response is enhanced in collagen-induced arthritis rats, the antigen presenting cells are activated abnormally and the immune tolerance is disturbed. Madecassoside treatment can downregulate the intestinal mucosal immune response and benefit for the induction and maintenance of intestinal immune tolerance.

Effects of hydromorphone-based patient-controlled intravenous analgesia on postoperative hypoxaemia: a randomised controlled non-inferiority clinical trial.

OBJECTIVE: This study aimed to compare the effects of patient-controlled intravenous analgesia (PCIA) with and without low-basal infusion on postoperative hypoxaemia. DESIGN: A randomised parallel-group non-inferiority trial. SETTING: The trial was conducted at a grade-A tertiary hospital from December 2021 to August 2022. PARTICIPANTS: 160 adults undergoing gastrointestinal tumour surgery and receiving postoperative PCIA. INTERVENTIONS: Participants randomly received a low-basal (0.1 mg/hour of hydromorphone) or no-basal infusion PCIA for postoperative 48 hours. PRIMARY AND SECONDARY OUTCOME MEASURES: Primary outcome was area under curve (AUC) per hour for hypoxaemia, defined as pulse oxygen saturation (SpO2) <95%. Secondary outcomes included: AUC per hour at SpO2<90% and <85%, hydromorphone consumption, ambulation time and analgesic outcomes up to 48 hours after surgery. RESULTS: Among 160 randomised patients, 159 completed the trial. An intention-to-treat analysis showed that AUC per hour (SpO2<95%) was greater in the low-basal infusion group compared with the no-basal infusion group, with a median difference of 0.097 (95% CI 0.001 to 0.245). Non-inferiority (margin: ratio of means (ROM) of 1.25) was not confirmed since the ROM between the two groups was 2.146 (95% CI 2.138 to 2.155). Hydromorphone consumption was higher in the low-basal group than in the no-basal group (median: 5.2 mg versus 1.6 mg, p<0.001). Meanwhile, there were no differences in the AUC values at the other two hypoxaemia thresholds, in ambulation time, or pain scores between the groups. CONCLUSIONS: Among the patients receiving hydromorphone PCIA after gastrointestinal tumour resection, low-basal infusion was inferior to no-basal infusion PCIA for postoperative hypoxaemia at SpO2<95% up to 48 hours after surgery. TRIAL REGISTRATION NUMBER: ChiCTR2100054317.

Spinal Nmur2-positive Neurons Play a Crucial Role in Mechanical Itch.

The dorsal spinal cord is crucial for the transmission and modulation of multiple somatosensory modalities, such as itch, pain, and touch. Despite being essential for the well-being and survival of an individual, itch and pain, in their chronic forms, have increasingly been recognized as clinical problems. Although considerable progress has been made in our understanding of the neurochemical processing of nociceptive and chemical itch sensations, the neural substrate that is crucial for mechanical itch processing is still unclear. Here, using genetic and functional manipulation, we identified a population of spinal neurons expressing neuromedin U receptor 2 (Nmur2+) as critical elements for mechanical itch. We found that spinal Nmur2+ neurons are predominantly excitatory neurons, and are enriched in the superficial laminae of the dorsal horn. Pharmacogenetic activation of cervical spinal Nmur2+ neurons evoked scratching behavior. Conversely, the ablation of these neurons using a caspase-3-based method decreased von Frey filament-induced scratching behavior without affecting responses to other somatosensory modalities. Similarly, suppressing the excitability of cervical spinal Nmur2+ neurons via the overexpression of functional Kir2.1 potassium channels reduced scratching in response to innocuous mechanical stimuli, but not to pruritogen application. At the lumbar level, pharmacogenetic activation of these neurons evoked licking and lifting behaviors. However, ablating these neurons did not affect the behavior associated with acute pain. Thus, these results revealed the crucial role of spinal Nmur2+ neurons in mechanical itch. Our study provides important insights into the neural basis of mechanical itch, paving the way for developing novel therapies for chronic itch. PERSPECTIVE: Excitatory Nmur2+ neurons in the superficial dorsal spinal cord are essential for mechanical but not chemical itch information processing. These spinal Nmur2+ neurons represent a potential cellular target for future therapeutic interventions against chronic itch. Spinal and supraspinal Nmur2+ neurons may play different roles in pain signal processing.

Single-neuron projectome-guided analysis reveals the neural circuit mechanism underlying endogenous opioid antinociception.

Endogenous opioid antinociception is a self-regulatory mechanism that reduces chronic pain, but its underlying circuit mechanism remains largely unknown. Here, we showed that endogenous opioid antinociception required the activation of mu-opioid receptors (MORs) in GABAergic neurons of the central amygdala nucleus (CEA) in a persistent-hyperalgesia mouse model. Pharmacogenetic suppression of these CEAMOR neurons, which mimics the effect of MOR activation, alleviated the persistent hyperalgesia. Furthermore, single-neuron projection analysis revealed multiple projectome-based subtypes of CEAMOR neurons, each innervating distinct target brain regions. We found that the suppression of axon branches projecting to the parabrachial nucleus (PB) of one subtype of CEAMOR neurons alleviated persistent hyperalgesia, indicating a subtype- and axonal-branch-specific mechanism of action. Further electrophysiological analysis revealed that suppression of a distinct CEA-PB disinhibitory circuit controlled endogenous opioid antinociception. Thus, this study identified the central neural circuit that underlies endogenous opioid antinociception, providing new insight into the endogenous pain modulatory mechanisms.

HOXD10 attenuates renal fibrosis by inhibiting NOX4-induced ferroptosis.

In chronic kidney disease (CKD), renal fibrosis is an unavoidable result of various manifestations. However, its pathogenesis is not yet fully understood. Here, we revealed the novel role of Homeobox D10 (HOXD10) in CKD-related fibrosis. HOXD10 expression was downregulated in CKD-related in vitro and in vivo fibrosis models. UUO model mice were administered adeno-associated virus (AAV) containing HOXD10, and HOXD10 overexpression plasmids were introduced into human proximal tubular epithelial cells induced by TGF-ß1. The levels of iron, reactive oxygen species (ROS), lipid ROS, the oxidized glutathione/total glutathione (GSSG/GSH) ratio, malonaldehyde (MDA), and superoxide dismutase (SOD) were determined using respective assay kits. Treatment with AAV-HOXD10 significantly attenuated fibrosis and renal dysfunction in UUO model mice by inhibiting NOX4 transcription, ferroptosis pathway activation, and oxidative stress. High levels of NOX4 transcription, ferroptosis pathway activation and profibrotic gene expression induced by TGF-ß1/erastin (a ferroptosis agonist) were abrogated by HOXD10 overexpression in HK-2 cells. Moreover, bisulfite sequencing PCR result determined that HOXD10 showed a hypermethylated level in TGF-ß1-treated HK-2 cells. The binding of HOXD10 to the NOX4 promoter was confirmed by chromatin immunoprecipitation (ChIP) analysis and dual-luciferase reporter assays. Targeting HOXD10 may represent an innovative therapeutic strategy for fibrosis treatment in CKD.

Analysis of Soluble Sugar Content in Minute Quantities of Rice Tissues by GC-MS.

Soluble sugars play key roles in plant growth, development, and adaption to the environment. Characterizing sugar content profiling of plant tissues promotes our understanding of the mechanisms underlying these plant processes. Several technologies have been developed to quantitate soluble sugar content in plant tissues; however, it is difficult with only minute quantities of plant tissues available. Here, we provide a detailed protocol for gas chromatography mass spectrometry (GC-MS)-based soluble sugar profiling of rice tissues that offers a good balance of sensitivity and reliability, and is considerably more sensitive and accurate than other reported methods. We summarize all the steps from sample collection and soluble sugar extraction to derivatization procedures of the soluble extracted sugars, instrumentation settings, and data analysis.

Plasmodesmata play pivotal role in sucrose supply to Meloidogyne graminicola-caused giant cells in rice.

On infection, plant-parasitic nematodes establish feeding sites in roots from which they take up carbohydrates among other nutrients. Knowledge on how carbohydrates are supplied to the nematodes' feeding sites is limited. Here, gene expression analyses showed that RNA levels of OsSWEET11 to OsSWEET15 were extremely low in both Meloidogyne graminicola (Mg)-caused galls and noninoculated roots. All the rice sucrose transporter genes, OsSUT1 to OsSUT5, were either down-regulated in Mg-caused galls compared with noninoculated rice roots or had very low transcript abundance. OsSUT1 was the only gene up-regulated in galls, at 14 days postinoculation (dpi), after being highly down-regulated at 3 and 7 dpi. OsSUT4 was down-regulated at 3 dpi. No noticeable OsSUTs promoter activities were detected in Mg-caused galls of pOsSUT1 to -5::GUS rice lines. Loading experiments with carboxyfluorescein diacetate (CFDA) demonstrated that symplastic connections exist between phloem and Mg-caused giant cells (GCs). According to data from OsGNS5- and OsGSL2-overexpressing rice plants that had decreased and increased callose deposition, respectively, callose negatively affected Mg parasitism and sucrose supply to Mg-caused GCs. Our results suggest that plasmodesmata-mediated sucrose transport plays a pivotal role in sucrose supply from rice root phloem to Mg-caused GCs, and OsSWEET11 to -15 and OsSUTs are not major players in it, although further functional analysis is needed for OsSUT1 and OsSUT4.

Monitoring the Depth of Anesthesia Through the Use of Cerebral Hemodynamic Measurements Based on Sample Entropy Algorithm.

OBJECTIVE: The aim of this study is to explore the relationship between the depth of anesthesia and the cerebral hemodynamic variables during the complete anesthesia process. METHODS: In this study, near-infrared spectroscopy signals were used to record eight kinds of cerebral hemodynamic variables, including left, right, proximal, distal deoxygenated (Hb) and oxygenated (HbO2) hemoglobin concentration changes. Then, by measuring the complexity information of cerebral hemodynamic variables, the sample entropy was calculated as a new index of monitoring the depth of anesthesia. RESULTS: By means of receiver operating characteristic curve analysis, the sample entropy approach was proved to effectively discriminate anesthesia maintenance and waking phases. The discriminatory ability of HbO2 signals was stronger than that of Hb signals and the distal signals had weaker discrimination capability when compared with the proximal signals. In addition, there was statistical consistency between the bispectral index and sample entropy of cerebral hemodynamic variables during the complete anesthesia process. Moreover, the cerebral hemodynamic signals could not be interfered by clinical electrical devices. CONCLUSION: The sample entropy of cerebral hemodynamic variables could be suitable as a new index for monitoring the depth of anesthesia. SIGNIFICANCE: This study is very meaningful for developing new modality and decoding methods in perspective of anesthesia surveillance and may result in the anesthesia monitoring system with high performance.

Sodium chloride facilitates the secretohalophyte Atriplex canescens adaptation to drought stress.

Atriplex canescens is a C4 shrub with excellent adaptation to saline and arid environments. Our previous study showed that the secretion of excessive Na+ into leaf salt bladders is a primary strategy in salt tolerance of A. canescens and external 100 mM NaCl can substantially stimulate its growth. To investigate whether NaCl could facilitate Atriplex canescens response to drought stress, five-week-old seedlings were subjected to drought stress (30% of field water capacity) in the presence or absence of additional 100 mM NaCl. The results showed that, under drought stress, the addition of NaCl could substantially improve the growth of A. canescens by increasing leaf relative water content, enhancing photosynthetic activity and inducing a significant declined leaf osmotic potential (Ψs). The addition of NaCl significantly increased Na+ concentration in leaf salt bladders and the Na+ contribution to leaf Ψs, while had no adverse effects on K+ accumulation in leaf laminae. Therefore, the large accumulation of Na+ in salt bladders for enhancing osmotic adjustment (OA) ability is a vital strategy in A. canescens responding to drought stress. In addition, the concentration of free proline, bataine and soluble sugars exhibited a significant increase in the presence of NaCl under drought stress, and the betaine contribution to leaf Ψs was significantly increased by additional NaCl compared with that under drought treatment alone, suggesting that compatible solutes are also involved in OA in addition to functioning as protectants to alleviate water deficit injury.

Different neuronal populations mediate inflammatory pain analgesia by exogenous and endogenous opioids.

Mu-opioid receptors (MORs) are crucial for analgesia by both exogenous and endogenous opioids. However, the distinct mechanisms underlying these two types of opioid analgesia remain largely unknown. Here, we demonstrate that analgesic effects of exogenous and endogenous opioids on inflammatory pain are mediated by MORs expressed in distinct subpopulations of neurons in mice. We found that the exogenous opioid-induced analgesia of inflammatory pain is mediated by MORs in Vglut2+ glutamatergic but not GABAergic neurons. In contrast, analgesia by endogenous opioids is mediated by MORs in GABAergic rather than Vglut2+ glutamatergic neurons. Furthermore, MORs expressed at the spinal level is mainly involved in the analgesic effect of morphine in acute pain, but not in endogenous opioid analgesia during chronic inflammatory pain. Thus, our study revealed distinct mechanisms underlying analgesia by exogenous and endogenous opioids, and laid the foundation for further dissecting the circuit mechanism underlying opioid analgesia.

The synergistic effects of sodium and potassium on the xerophyte Apocynum venetum in response to drought stress.

Apocynum venetum is an eco-economic plant species with high adaptability to saline and arid environments. Our previous work has found that A. venetum could absorb large amount of Na+ and maintain high K+ level under saline conditions. To investigate whether K+ and Na+ could simultaneously enhance drought resistance in A. venetum, seedlings were exposed to osmotic stress (-0.2 MPa) in the presence or absence of additional 25 mM NaCl under low (0.01 mM) and normal (2.5 mM) K+ supplying conditions, respectively. The results showed that A. venetum should be considered as a typical K+-efficient species since its growth was unimpaired and possessed a strong K+ uptake and prominent K+ utilization efficiency under K+ deficiency condition. Leaf K+ concentration remained stable or was even significantly increased under osmotic stress in the presence or absence of NaCl, compared with that under control condition, regardless of whether the K+ supply was sufficient or not, and the contribution of K+ to leaf osmotic potential consistently exceeded 37%, indicating K+ is the uppermost contributor to osmotic adjustment of A. venetum. Under osmotic stress, the addition of 25 mM NaCl significantly increase Na+ accumulation in leaves and the contribution of Na+ to osmotic adjustment, thus improving the relative water content, concomitantly, promoting the photosynthetic activity resulting in an enhancement of overall plant growth. These findings suggested that, K+ and Na+ simultaneously play crucial roles in the osmotic adjustment and the maintenance of water status and photosynthetic activity, which is beneficial for A. venetum to cope with drought stress.

Transcriptomic Profiling Identifies Candidate Genes Involved in the Salt Tolerance of the Xerophyte Pugionium cornutum.

The xerophyte Pugionium cornutum adapts to salt stress by accumulating inorganic ions (e.g., Cl-) for osmotic adjustment and enhancing the activity of antioxidant enzymes, but the associated molecular basis remains unclear. In this study, we first found that P. cornutum could also maintain cell membrane stability due to its prominent ROS-scavenging ability and exhibits efficient carbon assimilation capacity under salt stress. Then, the candidate genes associated with the important physiological traits of the salt tolerance of P. cornutum were identified through transcriptomic analysis. The results showed that after 50 mM NaCl treatment for 6 or 24 h, multiple genes encoding proteins facilitating Cl- accumulation and NO3- homeostasis, as well as the transport of other major inorganic osmoticums, were significantly upregulated in roots and shoots, which should be favorable for enhancing osmotic adjustment capacity and maintaining the uptake and transport of nutrient elements; a large number of genes related to ROS-scavenging pathways were also significantly upregulated, which might be beneficial for mitigating salt-induced oxidative damage to the cells. Meanwhile, many genes encoding components of the photosynthetic electron transport pathway and carbon fixation enzymes were significantly upregulated in shoots, possibly resulting in high carbon assimilation efficiency in P. cornutum. Additionally, numerous salt-inducible transcription factor genes that probably regulate the abovementioned processes were found. This work lays a preliminary foundation for clarifying the molecular mechanism underlying the adaptation of xerophytes to harsh environments.

[Comparative study on internal quality of various Chrysanthemum morifolium].

OBJECTIVE: To study the quality and genetic diversity of Chrysanthemun morifolium, the chemical constituents of 20 medicinal chrysanthemum cultivars in China were compared. METHOD: Chemical constituents of the 20 cultivars were compared in three types of index: chlorogenic acid, flavonoid and volatile oil. RESULT: There are visible differences on the contents of chlorogenic acid, flavonoid and volatile oil between the cultivars. CONCLUSION: Each cultivar has its own internal quality, and it is affected by many factors. The chemical constituents of the cultivars showed the genetic diversity in medicinal chrysanthemums of China.