Noncanonical protein kinase A activation by oligomerization of regulatory subunits as revealed by inherited Carney complex mutations.

Familial mutations of the protein kinase A (PKA) R1α regulatory subunit lead to a generalized predisposition for a wide range of tumors, from pituitary adenomas to pancreatic and liver cancers, commonly referred to as Carney complex (CNC). CNC mutations are known to cause overactivation of PKA, but the molecular mechanisms underlying such kinase overactivity are not fully understood in the context of the canonical cAMP-dependent activation of PKA. Here, we show that oligomerization-induced sequestration of R1α from the catalytic subunit of PKA (C) is a viable mechanism of PKA activation that can explain the CNC phenotype. Our investigations focus on comparative analyses at the level of structure, unfolding, aggregation, and kinase inhibition profiles of wild-type (wt) PKA R1α, the A211D and G287W CNC mutants, as well as the cognate acrodysostosis type 1 (ACRDYS1) mutations A211T and G287E. The latter exhibit a phenotype opposite to CNC with suboptimal PKA activation compared with wt. Overall, our results show that CNC mutations not only perturb the classical cAMP-dependent allosteric activation pathway of PKA, but also amplify significantly more than the cognate ACRDYS1 mutations nonclassical and previously unappreciated activation pathways, such as oligomerization-induced losses of the PKA R1α inhibitory function.

Divergent allostery reveals critical differences between structurally homologous regulatory domains of Plasmodium falciparum and human protein kinase G.

Malaria is a life-threatening infectious disease primarily caused by the Plasmodium falciparum parasite. The increasing resistance to current antimalarial drugs and their side effects has led to an urgent need for novel malaria drug targets, such as the P. falciparum cGMP-dependent protein kinase (pfPKG). However, PKG plays an essential regulatory role also in the human host. Human cGMP-dependent protein kinase (hPKG) and pfPKG are controlled by structurally homologous cGMP-binding domains (CBDs). Here, we show that despite the structural similarities between the essential CBDs in pfPKG and hPKG, their respective allosteric networks differ significantly. Through comparative analyses of chemical shift covariance analyses, molecular dynamics simulations, and backbone internal dynamics measurements, we found that conserved allosteric elements within the essential CBDs are wired differently in pfPKG and hPKG to implement cGMP-dependent kinase activation. Such pfPKG versus hPKG rewiring of allosteric networks was unexpected because of the structural similarity between the two essential CBDs. Yet, such finding provides crucial information on which elements to target for selective inhibition of pfPKG versus hPKG, which may potentially reduce undesired side effects in malaria treatments.

Structural determinants of the interactions of catechins with Aß oligomers and lipid membranes.

The aberrant self-assembly of intrinsically disordered proteins (IDPs) into soluble oligomers and their interactions with biological membranes underlie the pathogenesis of numerous neurodegenerative diseases, including Alzheimer's disease. Catechins have emerged as useful tools to reduce the toxicity of IDP oligomers by modulating their interactions with membranes. However, the structural determinants of catechin binding to IDP oligomers and membranes remain largely elusive. Here, we assemble a catechin library by combining several naturally occurring chemical modifications and, using a coupled NMR-statistical approach, we map at atomic resolution the interactions of such library with the Alzheimer's-associated amyloid-beta (Aß) oligomers and model membranes. Our results reveal multiple catechin affinity drivers and show that the combination of affinity-reducing covalent changes may lead to unexpected net gains in affinity. Interestingly, we find that the positive cooperativity is more prevalent for Aß oligomers than membrane binding, and that the determinants underlying catechin recognition by membranes are markedly different from those dissected for Aß oligomers. Notably, we find that the unanticipated positive cooperativity arises from the critical regulatory role of the gallate catechin moiety, which recruits previously disengaged substituents into the binding interface and leads to an overall greater compaction of the receptor-bound conformation. Overall, the previously elusive structural attributes mapped here provide an unprecedented foundation to establish structure-activity relationships of catechins.

Anionic Hybrid Copolymerization of Sulfur with Acrylate: Strategy for Synthesis of High-Performance Sulfur-Based Polymers.

Copolymerization of elemental sulfur (S8) with vinyl monomers to develop new polymer materials is significant. Here, for the first time, we report the anionic hybrid copolymerization of S8 with acrylate at 25 °C, yielding a copolymer with short polysulfide segments; i.e., each of them consists of only one to four sulfur atoms. The formation of a longer polysulfide segment would be ceaselessly disrupted by carbon anions through the chain-transfer reaction. The copolymer of S8 with diacrylate was cross-linked and exhibited excellent mechanical properties, with an ultimate tensile strength as high as 10.7 MPa and a breaking strain of 22%. Furthermore, the introduction of tertiary amide groups to the copolymer enabled it not only to be reprocessed via press molding at room temperature but also to exhibit self-healing properties without external intervention. This study provides a facile strategy to synthesize high-performance sulfur-based copolymers under mild conditions.

Influences of local and global context on local orientation perception.

Visual context modulates perception of local orientation attributes. These spatially very localised effects are considered to correspond to specific excitatory-inhibitory connectivity patterns of early visual areas as V1, creating perceptual tilt repulsion and attraction effects. Here, orientation misperception of small Gabor stimuli was used as a probe of this computational structure by sampling a large spatio-orientation space to reveal expected asymmetries due to the underlying neuronal processing. Surprisingly, the results showed a regular iso-orientation pattern of nearby location effects whose reference point was globally modulated by the spatial structure, without any complex interactions between local positions and orientation. This pattern of results was confirmed by the two perceptual parameters of bias and discrimination ability. Furthermore, the response times to stimulus configuration displayed variations that further provided evidence of how multiple early visual stages affect perception of simple stimuli.

Multiple-photon bundle emission in the n-photon Jaynes-Cummings model.

We study the multiple-photon bundle emission in the n-photon Jaynes-Cummings model composed of a two-level system coupled to a single-mode optical field via the n-photon exciting process. Here, the two-level system is strongly driven by a near-resonant monochromatic field, and hence the system can work in the Mollow regime, in which a super-Rabi oscillation between the zero-photon state and the n-photon state can take place under proper resonant conditions. We calculate the photon number populations and the standard equal-time high-order correlation functions, and find that the multiple-photon bundle emission can occur in this system. The multiple-photon bundle emission is also confirmed by investigating the quantum trajectories of the state populations and both the standard and generalized time-delay second-order correlation functions for multiple-photon bundle. Our work paves the way towards the study of multiple-photon quantum coherent devices, with potential application in quantum information sciences and technologies.

N6-methyladenosine-modified oncofetal lncRNA MIR4435-2HG contributed to stemness features of hepatocellular carcinoma cells by regulating rRNA 2'-O methylation.

BACKGROUND: The unique expression pattern endows oncofetal genes with great value in cancer diagnosis and treatment. However, only a few oncofetal genes are available for clinical use and the underlying mechanisms that drives the fetal-like reprogramming of cancer cells remain largely unknown. METHODS: Microarray assays and bioinformatic analyses were employed to screen for potential oncofetal long non-coding RNAs (lncRNAs) in hepatocellular carcinoma (HCC). The expression levels of MIR4435-2HG, NOP58 ribonucleoprotein (NOP58), insulin like growth factor 2 mRNA binding protein 1 (IGF2BP1) and stem markers were detected by quantitative polymerase chain reaction. The 2'-O-methylation (2'-O-Me) status of rRNA were detected through reverse transcription at low dNTP concentrations followed by PCR. The regulation of MIR4435-2HG by IGF2BP1 was explored by RNA immunoprecipitation (RIP), methylated RIP (MeRIP) and dual-luciferase assays. The interaction between MIR4435-2HG and NOP58 was investigated by RNA Pulldown, RIP and protein stability assays. In vitro and in vivo function assays were performed to detect the roles of MIR4435-2HG/NOP58 in HCC. RESULTS: MIR4435-2HG was an oncofetal lncRNA associated with poor prognosis in HCC. Functional experiments showed that overexpression of MIR4435-2HG remarkably enhanced the stem-cell properties of HCC cells, promoting tumorigenesis in vitro and in vivo. Mechanically, MIR4435-2HG directly bound NOP58 and IGF2BP1. IGF2BP1 upregulated MIR4435-2HG expression in HCC through N6-methyladenosine (m6A) modification. Moreover, MIR4435-2HG protected NOP58 from degradation, which raised rRNA 2'-O-Me levels and promoted internal ribosome entry site (IRES)-dependent translation of oncogenes. CONCLUSIONS: This study identified an oncofetal lncRNA MIR4435-2HG, characterized the role of MIR4435-2HG/NOP58 in stemness maintenance and proliferation of HCC cells, and confirmed m6A as a 'driver' that reactivated MR4435-2HG expression in HCC.

Black phosphorous-based biomaterials for bone defect regeneration: a systematic review and meta-analysis.

Critical-sized bone defects are always difficult to treat, and they are associated with a significant burden of disease in clinical practice. In recent decades, due to the fast development of biomaterials and tissue engineering, many bioinspired materials have been developed to treat large bone defects. Due to the excellent osteoblastic ability of black phosphorous (BP), many BP-based biomaterials have been developed to treat bone defects. Therefore, there are abundant studies as well as a tremendous amount of research data. It is urgent to conduct evidence-based research to translate these research data and results into validated scientific evidence. Therefore, in our present study, a qualitative systematic review and a quantitative meta-analysis were performed. Eighteen studies were included in a systematic review, while twelve studies were included in the meta-analysis. Our results showed that the overall quality of experimental methods and reports of biomaterials studies was still low, which needs to be improved in future studies. Besides, we also proved the excellent osteoblastic ability of BP-based biomaterials. But we did not find a significant effect of near-infrared (NIR) laser in BP-based biomaterials for treating bone defects. However, the quality of the evidence presented by included studies was very low. Therefore, to accelerate the clinical translation of BP-based biomaterials, it is urgent to improve the quality of the study method and reporting in future animal studies. More evidence-based studies should be conducted to enhance the quality and clinical translation of BP-based biomaterials.

Neurosecretory protein GL in GIFT tilapia (Oreochromis niloticus): cDNA cloning, tissue distribution and effects of feeding on its expression.

Neurosecretory protein GL (NPGL), a novel neuropeptide, has been identified in the hypothalamus of chicks and rodents. NPGL plays a crucial role in monitoring energetic status via the regulation of feeding and metabolism. However, no study on NPGL has been reported in fish thus far. In the present study, the full-length cDNA of NPGL was identified from the hypothalamus of GIFT tilapia (Oreochromis niloticus). The ORF of tilapia NPGL is 471 bp and encodes a precursor peptide with a size of 156 a.a, consisting of a 26 a.a signal peptide and an 82 a.a mature peptide. Tissue distribution profiles of npgl in tilapia were acquired using semiquantitative PCR and in situ hybridization (ISH). The results showed that the highest npgl mRNA is expressed in the telencephalic-preoptic complex, which comprises both the telencephalon and the anterior preoptic area (POA) of male tilapia, and in the ovary of female tilapia. In addition, in male tilapia, the ISH results showed that the cells containing npgl mRNA were distributed exclusively in the anterior periventricular pretectal nucleus (Ppa) of the POA. FISH results demonstrated that npgl mRNA is also expressed in the lateral tuberal nucleus of the hypothalamus (NLT). Real-time PCR showed that npgl mRNA significantly increased in the telencephalic-preoptic complex of male tilapia that were fasted for 24 h and then fed a full diet for 20 min compared with the unfed group. Results of the FISH study showed that parvocellular cells containing npgl mRNA in the Ppa of fed fish were apparently more abundant than those of the unfed group. Few npgl positive signals also appeared in the NLT after full feeding, where pomc mRNA is highly expressed. These results indicate that NPGL may be a short-term satiety factor in fish and that the coexpression of NPGL and POMC may be present in the hypothalamus of male tilapia.

Transcriptome Analysis of Peripheral Blood Mononuclear Cells Response in Patients with Severe COVID-19 Reveals Crucial Genes Regulating Protein Ubiquitination.

BACKGROUND We sought to further our understanding of the biological characteristics underlying severe COVID-19. MATERIAL AND METHODS RNA sequencing (RNA-Seq) analysis was used to evaluate peripheral blood mononuclear cells from 4 patients with severe COVID-19 and 4 healthy controls. We performed gene expression analyses to detect differentially expressed genes (DEGs). Enrichment analyses were performed to identify their molecular processes and signaling pathways, and the protein-protein interaction network was constructed to extract the core gene cluster. The investigation of protein-chemical interactions and regulatory signatures for specific regulatory checkpoints and powerful chemical agents was then conducted for these essential genes. Finally, we used single-cell RNA-Seq analysis from an online platform to show how these genes were expressed differently, depending on the kind of cell. RESULTS A total of 268 DEGs were found. The biological process of protein ubiquitination was later discovered to be highly influenced by the core gene cluster (ITCH, TRIM21, RNF130, FBXO11, UBE2J1, and ASB16) at the transcriptome level. Six transcription factors, FNIC, FOXA1, YY1, GATA2, MET2A, and FOXC1, as well as miRNAs hsa-miR-1-3p and hsa-miR-27a-3p were identified. We found a potent chemical agent, copper sulfate, may regulate protein ubiquitination genes cooperatively, and the genes regulating protein ubiquitination could be expressed highly on the macrophages. CONCLUSIONS Taken together, we suggest that protein ubiquitination is a crucial functional process in patients with severe COVID-19. This study will give a deeper insight into biological characteristics and progression of COVID-19 and facilitate development of novel therapeutics, leading to significant advancements in the COVID-19 pandemic.

Mechanism of allosteric inhibition in the Plasmodium falciparum cGMP-dependent protein kinase.

Most malaria deaths are caused by the protozoan parasite Plasmodium falciparum Its life cycle is regulated by a cGMP-dependent protein kinase (PfPKG), whose inhibition is a promising antimalaria strategy. Allosteric kinase inhibitors, such as cGMP analogs, offer enhanced selectivity relative to competitive kinase inhibitors. However, the mechanisms underlying allosteric PfPKG inhibition are incompletely understood. Here, we show that 8-NBD-cGMP is an effective PfPKG antagonist. Using comparative NMR analyses of a key regulatory domain, PfD, in its apo, cGMP-bound, and cGMP analog-bound states, we elucidated its inhibition mechanism of action. Using NMR chemical shift analyses, molecular dynamics simulations, and site-directed mutagenesis, we show that 8-NBD-cGMP inhibits PfPKG not simply by reverting a two-state active versus inactive equilibrium, but by sampling also a distinct inactive "mixed" intermediate. Surface plasmon resonance indicates that the ability to stabilize a mixed intermediate provides a means to effectively inhibit PfPKG, without losing affinity for the cGMP analog. Our proposed model may facilitate the rational design of PfPKG-selective inhibitors for improved management of malaria.

Atomic Resolution Map of Hierarchical Self-Assembly for an Amyloidogenic Protein Probed through Thermal 15N-R2 Correlation Matrices.

Soluble oligomers formed by amyloidogenic intrinsically disordered proteins are some of the most cytotoxic species linked to neurodegeneration. Due to the transient and heterogeneous nature of such oligomeric intermediates, the underlying self-association events often remain elusive. NMR relaxation measurements sensitive to zero-frequency spectral densities (J(0)), such as the 15N - R2 rates, are ideally suited to map sites of self-association at atomic resolution without the need of exogenous labels. Such experiments exploit the dynamic exchange between NMR visible monomers and slowly tumbling oligomers. However,15N - R2 rates are also sensitive to intrinsic monomer dynamics, and it is often difficult to discern these contributions from those arising from exchange with oligomers. Another challenge pertains to defining a hierarchy of self-association. Here, using the archetypical amyloidogenic protein alpha synuclein (αS), we show that the temperature-dependence of 15N - R2 effectively identifies self-association sites with reduced bias from internal dynamics. The key signature of the residues involved in self-association is a nonlinear temperature-dependence of 15N - R2 with a positive ΔR2/ΔT slope. These two hallmarks are systematically probed through a thermal R2 correlation matrix, from which the network of residues involved in self-association as well as the hierarchy of αS self-association sites is extracted through agglomerative clustering. We find that aggregation is initiated by residues within the NAC region that is solvent inaccessible in αS fibrils and eventually extends to the N-terminal segment harboring familial PD mutations. These hierarchical self-association maps help dissect the essential drivers of oligomerization and reveal how amyloid inhibitors affect oligomer formation.

Role of gibberellin and its three GID1 receptors in Jasminum sambac stem elongation and flowering.

MAIN CONCLUSION: Taken together, our results establish a reciprocal relationship between vine elongation and flowering, and reveal that GA is a positive signal for stem elogation but a negative regulator of flowering in this species. Vines or climbing plants exhibit vigorous vegetative shoot extension. GA have long been recognized as an important signal for seasonal stem elongation and flowering in many woody perennials. However, less is explored as how GA pathway is involved in the regulation of shoot extension in woody vines. Here, we investigated the role of GA and its signaling components in shoot elongation in Jasminum sambac. We found high accumulation of GA4 in the elongating internode, in contrast to a depletion of GAs in the floral differentiating shoot, which in turn featured a higher zeatin content, and a lower IAA and JA concentrations. This GA accumulation was coincident with the strong expression of JsGA20ox1 and JsGAS1 in the leaves, as well as of the JsGA2ox3 in the internode. Treatment of GA biosynthesis inhibitor reduced elongation while stimulated the terminal flowering. Remarkably, three B-type GA-receptor genes were abundantly expressed in both internodes and leaves of the extending shoots, which could enhance GA responsiveness in heterologous transgenic Arabidopsis. Furthermore, these JsGID1s showed distinct GA-dependent interaction with the JsDELLA in a yeast-two-hybrid assay. Taken together, our results establish a reciprocal relationship between vine elongation and flowering, and reveal that GA is a positive signal for stem elogation but a negative regulator of flowering in this species.

Manganese (II) chloride leads to dopaminergic neurotoxicity by promoting mitophagy through BNIP3-mediated oxidative stress in SH-SY5Y cells.

BACKGROUND: Manganese overexposure can induce neurotoxicity, lead to manganism and result in clinical manifestations similar to those of parkinsonism. However, the underlying molecular mechanism is still unclear. This study demonstrated that MnCl2 induces mitophagy and leads to neurotoxicity by promoting BNIP3-mediated reactive oxygen species (ROS) generation. METHODS: Human neuroblastoma SH-SY5Y cells were used throughout our experiments. Cell viability was detected by cell proliferation/toxicity test kits. Mitochondrial membrane potential was measured by flow cytometry. ROS generation was detected using a microplate reader. Protein levels were evaluated by Western blot. Transmission electron microscopy was used to evaluate mitochondrial morphology. Co-immunoprecipitation was used to verify the interaction between BNIP3 and LC3. RESULTS: MnCl2 led to loss of mitochondrial membrane potential and apoptosis of SH-SY5Y cells by enhancing expression of BNIP3 and conversion of LC3-I to LC3-II. Moreover, MnCl2 reduced expression of the mitochondrial marker protein TOMM20 and promoted interaction between BNIP3 and LC3. The results also indicated that a decrease in BNIP3 expression reduced the mitochondrial membrane potential loss, attenuated apoptosis and reduced mitochondrial autophagosome formation in SH-SY5Y cells after MnCl2 treatment. Finally, we found that manganese-induced ROS generation could be reversed by the antioxidant N-acetyl cysteine (NAC) or silencing BNIP3 expression. CONCLUSIONS: BNIP3 mediates MnCl2-induced mitophagy and neurotoxicity in dopaminergic SH-SY5Y cells through ROS. Thus, BNIP3 contributes to manganese-induced neurotoxicity by functioning as a mitophagy receptor protein.

[Research progress in lung parenchyma segmentation based on computed tomography].

Lung diseases such as lung cancer and COVID-19 seriously endanger human health and life safety, so early screening and diagnosis are particularly important. computed tomography (CT) technology is one of the important ways to screen lung diseases, among which lung parenchyma segmentation based on CT images is the key step in screening lung diseases, and high-quality lung parenchyma segmentation can effectively improve the level of early diagnosis and treatment of lung diseases. Automatic, fast and accurate segmentation of lung parenchyma based on CT images can effectively compensate for the shortcomings of low efficiency and strong subjectivity of manual segmentation, and has become one of the research hotspots in this field. In this paper, the research progress in lung parenchyma segmentation is reviewed based on the related literatures published at domestic and abroad in recent years. The traditional machine learning methods and deep learning methods are compared and analyzed, and the research progress of improving the network structure of deep learning model is emphatically introduced. Some unsolved problems in lung parenchyma segmentation were discussed, and the development prospect was prospected, providing reference for researchers in related fields.

Molecular Mechanism for the Suppression of Alpha Synuclein Membrane Toxicity by an Unconventional Extracellular Chaperone.

Alpha synuclein (αS) oligomers are a key component of Lewy bodies implicated in Parkinson's disease (PD). Although primarily intracellular, extracellular αS exocytosed from neurons also contributes to PD pathogenesis through a prion-like transmission mechanism. Here, we show at progressive degrees of resolution that the most abundantly expressed extracellular protein, human serum albumin (HSA), inhibits αS oligomer (αSn) toxicity through a three-pronged mechanism. First, endogenous HSA targets αSn with sub-µM affinity via solvent-exposed hydrophobic sites, breaking the catalytic cycle that promotes αS self-association. Second, HSA remodels αS oligomers and high-MW fibrils into chimeric intermediates with reduced toxicity. Third, HSA unexpectedly suppresses membrane interactions with the N-terminal and central αS regions. Overall, our findings suggest that the extracellular proteostasis network may regulate αS cell-to-cell transmission not only by reducing the populations of membrane-binding competent αS oligomers but possibly also by shielding the membrane interface from residual toxic species.

Pepper CaMLO6 Negatively Regulates Ralstonia solanacearum Resistance and Positively Regulates High Temperature and High Humidity Responses.

Plant mildew-resistance locus O (MLO) proteins influence susceptibility to powdery mildew. However, their roles in plant responses to other pathogens and heat stress remain unclear. Here, we showed that CaMLO6, a pepper (Capsicum annuum) member of MLO clade V, is a protein targeted to plasma membrane and probably endoplasmic reticulum. The transcript expression level of CaMLO6 was upregulated in the roots and leaves of pepper plants challenged with high temperature and high humidity (HTHH) and was upregulated in leaves but downregulated in roots of plants infected with the bacterial pathogen Ralstonia solanacearum. CaMLO6 was also directly upregulated by CaWRKY40 upon HTHH but downregulated by CaWRKY40 upon R. solanacearum infection. Virus-induced gene silencing of CaMLO6 significantly decreased pepper HTHH tolerance and R. solanacearum susceptibility. Moreover, CaMLO6 overexpression enhanced the susceptibility of Nicotiana benthamiana and pepper plants to R. solanacearum and their tolerance to HTHH, effects that were associated with the expression of immunity- and thermotolerance-associated marker genes, respectively. These results suggest that CaMLO6 acts as a positive regulator in response to HTHH but a negative regulator in response to R. solanacearum. Moreover, CaMLO6 is transcriptionally affected by R. solanacearum and HTHH; these transcriptional responses are at least partially regulated by CaWRKY40.

The transcriptional reprograming and functional identification of WRKY family members in pepper's response to Phytophthora capsici infection.

BACKGROUND: Plant transcription factors (TFs) are key transcriptional regulators to manipulate the regulatory network of host immunity. However, the globally transcriptional reprogramming of plant TF families in response to pathogens, especially between the resistant and susceptible host plants, remains largely unknown. RESULTS: Here, we performed time-series RNA-seq from a resistant pepper line CM334 and a susceptible pepper line EC01 upon challenged with Phytophthora capsici, and enrichment analysis indicated that WRKY family most significantly enriched in both CM334 and EC01. Interestingly, we found that nearly half of the WRKY family members were significantly up-regulated, whereas none of them were down-regulated in the two lines. These induced WRKY genes were greatly overlapped between CM334 and EC01. More strikingly, most of these induced WRKY genes were expressed in time-order patterns, and could be mainly divided into three subgroups: early response (3 h-up), mid response (24 h-up) and mid-late response (ML-up) genes. Moreover, it was found that the responses of these ML-up genes were several hours delayed in EC01. Furthermore, a total of 19 induced WRKY genes were selected for functional identification by virus-induced gene silencing. The result revealed that silencing of CaWRKY03-6, CaWRKY03-7, CaWRKY06-5 or CaWRKY10-4 significantly increase the susceptibility to P. capsici both in CM334 and EC01, indicating that they might contribute to pepper's basal defense against P. capsici; while silencing of CaWRKY08-4 and CaWRKY01-10 significantly impaired the disease resistance in CM334 but not in EC01, suggesting that these two WRKY genes are prominent modulators specifically in the resistant pepper plants. CONCLUSIONS: These results considerably extend our understanding of WRKY gene family in pepper's resistance against P. capsici and provide potential applications for genetic improvement against phytophthora blight.

Spectrometric detection of weak forces in cavity optomechanics.

We propose a spectrometric method to detect a classical weak force acting upon the moving end mirror in a cavity optomechanical system. The force changes the equilibrium position of the end mirror, and thus the resonance frequency of the cavity field depends on the force to be detected. As a result, the magnitude of the force can be inferred by analyzing the single-photon emission and scattering spectra of the optomechanical cavity. Since the emission and scattering processes are much faster than the characteristic mechanical dissipation, the influence of the mechanical thermal noise is negligible in this spectrometric detection scheme. We also extent this spectrometric method to detect a monochromatic oscillating force by utilizing an optomechanical coupling modulated at the same frequency as the force.

CaASR1 promotes salicylic acid- but represses jasmonic acid-dependent signaling to enhance the resistance of Capsicum annuum to bacterial wilt by modulating CabZIP63.

CabZIP63 acts positively in the resistance of pepper (Capsicum annuum) to bacterial wilt caused by Ralstonia solanacearum or tolerance to high-temperature/high-humidity stress, but it is unclear how CabZIP63 achieves its functional specificity against R. solanacearum. Here, CaASR1, an abscisic acid-, stress-, and ripening-inducible protein of C. annuum, was functionally characterized in modulating the functional specificity of CabZIP63 during the defense response of pepper to R. solanacearum. In pepper plants inoculated with R. solanacearum, CaASR1 was up-regulated before 24 h post-inoculation but down-regulated thereafter, and was down-regulated by high-temperature/high-humidity stress. Data from gene silencing and transient overexpression experiments indicated that CaASR1 acts as a positive regulator in the immunity of pepper against R. solanacearum and a negative regulator of thermotolerance. Pull-down combined with mass spectrometry revealed that CaASR1 interacted with CabZIP63 upon R. solanacearum infection; the interaction was confirmed by microscale thermophoresis and bimolecular fluorescence complementation assays.CaASR1 silencing upon R. solanacearum inoculation repressed CabZIP63-mediated transcription from the promoters of the salicylic acid (SA)-dependent CaPR1 and CaNPR1, but derepressed transcription of CaHSP24 and the jasmonic acid (JA)-dependent CaDEF1. Our findings suggest that CaASR1 acts as a positive regulator of the defense response of pepper to R. solanacearum by interacting with CabZIP63, enabling it to promote SA-dependent but repress JA-dependent immunity and thermotolerance during the early stages of infection.