BRASSINOSTEROID-SIGNALING KINASE1 modulates MAP KINASE15 phosphorylation to confer powdery mildew resistance in Arabidopsis.

Perception of pathogen-associated molecular patterns (PAMPs) by plant cell surface-localized pattern-recognition receptors (PRRs) triggers the first line of plant innate immunity. In Arabidopsis thaliana, the receptor-like cytoplasmic kinase BRASSINOSTEROID-SIGNALING KINASE1 (BSK1) physically associates with PRR FLAGELLIN SENSING2 and plays an important role in defense against multiple pathogens. However, how BSK1 transduces signals to activate downstream immune responses remains elusive. Previously, through whole-genome phosphorylation analysis using mass spectrometry, we showed that phosphorylation of the mitogen-activated protein kinase (MAPK) MPK15 was affected in the bsk1 mutant compared with the wild-type plants. Here, we demonstrated that MPK15 is important for powdery mildew fungal resistance. PAMPs and fungal pathogens significantly induced the phosphorylation of MPK15 Ser-511, a key phosphorylation site critical for the functions of MPK15 in powdery mildew resistance. BSK1 physically associates with MPK15 and is required for basal and pathogen-induced MPK15 Ser-511 phosphorylation, which contributes to BSK1-mediated fungal resistance. Taken together, our data identified MPK15 as a player in plant defense against powdery mildew fungi and showed that BSK1 promotes fungal resistance in part by enhancing MPK15 Ser-511 phosphorylation. These results uncovered a mechanism of BSK1-mediated disease resistance and provided new insight into the role of MAPK phosphorylation in plant immunity.

Molecular Insights into the Stability of Titanium in Electrolytes Containing Chlorine and Fluorine Ions.

Titanium and its alloys are protected by a compact and stable passive film, which confers resistance to corrosion by the primary halogen chloride (Cl-) while being less effective against fluoride (F-). Although researchers have recognized different macroscopic corrosion effects of these halide ions on titanium, the underlying mechanisms remain largely unexplored. In this work, the bonding of Cl-/F- with stable passive films was studied in neutral and acidic (pH = 2.3) conditions. The synergistic effect between the interfacial hydrogen bond (HB) structure and halogens on titanium corrosion was first revealed using first-principles calculation and Raman spectroscopy. F- forms more stable halogen-Ti bonds than Cl-, resulting in titanium degradation. The proton combined with F- exhibits a specific synergistic effect, causing corrosion of the passive film. The water hydrogen bond transformation index (HBTI) at the titanium/aqueous interface was 1.88 in an acidic solution containing F-, significantly higher than that in neutral/acid solutions containing Cl- (1.80/1.81) and a neutral solution containing F- (1.81). This work clarifies the structure-activity relationship between HBTI and the destruction of titanium passive films. We propose that the microstructure of the interfacial HB is an undeniable factor in the corrosion of titanium.

BRASSINOSTEROID-SIGNALING KINASE1 Phosphorylates MAPKKK5 to Regulate Immunity in Arabidopsis.

Arabidopsis (Arabidopsis thaliana) immune receptor FLAGELLIN SENSING2 (FLS2) rapidly forms a complex to activate pathogen-associated molecular pattern-triggered immunity (PTI) upon perception of the bacterial protein flagellin. The receptor-like cytoplasmic kinase BRASSINOSTEROID-SIGNALINGKINASE1 (BSK1) interacts with FLS2 and is critical for the activation of PTI. However, it is unknown how BSK1 transduces signals to activate downstream immune responses. We identified MEK Kinase5 (MAPKKK5) as a potential substrate of BSK1 by whole-genome phosphorylation analysis. In addition, we demonstrated that BSK1 interacts with and phosphorylates MAPKKK5. In the bsk1-1 mutant, the Ser-289 residue of MAPKKK5 was not phosphorylated as it was in the wild type. Similar to the bsk1 mutant, the mapkkk5 mutant displayed enhanced susceptibility to virulent and avirulent strains of the bacterial pathogen Pseudomonas syringae pv tomato DC3000, and to the fungal powdery mildew pathogen Golovinomyces cichoracearum Phosphorylation of the Ser-289 residue is not involved in MAPKKK5-triggered cell death but is critical for MAPKKK5-mediated resistance to both bacterial and fungal pathogens. Furthermore, MAPKKK5 interacts with multiple MAPK kinases, including MKK1, MKK2, MKK4, MKK5, and MKK6. Overall, these results indicate that BSK1 regulates plant immunity by phosphorylating MAPKKK5 and suggest a direct regulatory mode of signaling from the immune complex to the MAPK cascade.

Biosynthesis of D-glucaric acid from sucrose with routed carbon distribution in metabolically engineered Escherichia coli.

D-glucaric acid is a promising platform compound used to synthesize many other value-added or commodity chemicals. The engineering of Escherichia coli for efficiently converting D-glucose to D-glucaric acid has been attempted for several years, with mixed sugar fermentation recently gaining growing interests due to the increased D-glucaric acid yield. Here, we co-expressed cscB, cscA, cscK, ino1, miox, udh, and suhB in E. coli BL21 (DE3), functionally constructing an unreported route from sucrose to D-glucaric acid. Further deletion of chromosomal zwf, pgi, ptsG, uxaC, gudD, over-expression of glk, and use of a D-fructose-dependent translation control system for pgi enabled the strain to use sucrose as the sole carbon source while achieving a high product titer and yield. The titer of D-glucaric acid in M9 medium containing 10 g/L sucrose reached ~1.42 g/L, with a yield of ~0.142 g/g on sucrose.

BR-SIGNALING KINASE1 physically associates with FLAGELLIN SENSING2 and regulates plant innate immunity in Arabidopsis.

Pathogen-associated molecular pattern (PAMP)-trigged immunity (PTI) is the first defensive line of plant innate immunity and is mediated by pattern recognition receptors. Here, we show that a mutation in BR-SIGNALING KINASE1 (BSK1), a substrate of the brassinosteroid (BR) receptor BRASSINOSTEROID INSENSITIVE1, suppressed the powdery mildew resistance caused by a mutation in ENHANCED DISEASE RESISTANCE2, which negatively regulates powdery mildew resistance and programmed cell death, in Arabidopsis thaliana. A loss-of-function bsk1 mutant displayed enhanced susceptibility to virulent and avirulent pathogens, including Golovinomyces cichoracearum, Pseudomonas syringae, and Hyaloperonospora arabidopsidis. The bsk1 mutant also accumulated lower levels of salicylic acid upon infection with G. cichoracearum and P. syringae. BSK1 belongs to a receptor-like cytoplasmic kinase family and displays kinase activity in vitro; this kinase activity is required for its function. BSK1 physically associates with the PAMP receptor FLAGELLIN SENSING2 and is required for a subset of flg22-induced responses, including the reactive oxygen burst, but not for mitogen-activated protein kinase activation. Our data demonstrate that BSK1 is involved in positive regulation of PTI. Together with previous findings, our work indicates that BSK1 represents a key component directly involved in both BR signaling and plant immunity.

Novel DNA Biosensing Platform for Detecting HIV Integrase for Highly Sensitive and Quantitative HIV Detection, Diagnosis, and Therapeutic Monitoring.

Straightforward, sensitive, and specific human immunodeficiency virus (HIV) assays are urgently needed. The creation of a point-of-care (POC) device for decentralized diagnostics has the potential to significantly reduce the time to treatment, especially for infectious diseases. Notably, however, many POC solutions proposed to date fall short of meeting the ASSURED guidelines, which are crucial for effective deployment in the field. Herein, we developed a DNA biosensor platform for the specific and quantitative detection of HIV. The platform contains a rolling circle amplification (RCA)-based DNA biosensor and a portable fluorescence detector, in which HIV-encoded integrase (IN) enzyme activity is used as a biomarker to achieve HIV-specific detection. The cleavage and integration reaction of IN on the sensor surface and RCA are combined in this detection platform to perform detection signal cascade amplification, ultimately achieving a detection limit of 0.125 CFU/µL of HIV particles. Moreover, the DNA sensor system exhibited high sensitivity and accuracy for detecting HIV in clinical samples, suggesting that it has potential for application in clinical settings to detect retroviruses other than HIV. In addition, quantitative detection based on this biosensing platform was significantly correlated with the CD4+ lymphocytes count, which can provide guidance for antiretroviral therapy and which affects long-term death risk assessment in HIV patients. Therefore, this DNA biosensing platform based on IN activity is expected to be useful for rapid HIV testing, diagnosis, and treatment monitoring, enabling the development of new POC diagnostic tests and will thus be highly valuable for developing HIV prevention strategies and effective treatments.

Proteomic analysis reveals LRPAP1 as a key player in the micropapillary pattern metastasis of lung adenocarcinoma.

Objectives: Lung adenocarcinomas have different prognoses depending on their histological growth patterns. Micropapillary growth within lung adenocarcinoma, particularly metastasis, is related to dismal prognostic outcome. Metastasis accounts for a major factor leading to mortality among lung cancer patients. Understanding the mechanisms underlying early stage metastasis can help develop novel treatments for improving patient survival. Methods: Here, quantitative mass spectrometry was conducted for comparing protein expression profiles among various histological subtypes, including adenocarcinoma in situ, minimally invasive adenocarcinoma, and invasive adenocarcinoma (including acinar and micropapillary [MIP] types). To determine the mechanism of MIP-associated metastasis, we identified a protein that was highly expressed in MIP. The expression of the selected highly expressed MIP protein was verified via immunohistochemical (IHC) analysis and its function was validated by an in vitro migration assay. Results: Proteomic data revealed that low-density lipoprotein receptor-related protein-associated protein 1 (LRPAP1) was highly expressed in MIP group, which was confirmed by IHC. The co-expressed proteins in this study, PSMD1 and HSP90AB1, have been reported to be highly expressed in different cancers and play an essential role in metastasis. We observed that LRPAP1 promoted lung cancer progression, including metastasis, invasion and proliferation in vitro and in vivo. Conclusion: LRPAP1 is necessary for MIP-associated metastasis and is the candidate novel anti-metastasis therapeutic target.

E2F7 serves as a potential prognostic biomarker for lung adenocarcinoma.

E2F transcription factors (E2Fs) are a family of transcription factors critical regulators of the cell cycle, apoptosis, and differentiation, thus influencing tumorigenesis. However, the specific roles of E2Fs in lung adenocarcinoma (LUAD) remain unclear. Data from The Cancer Genome Atlas (TCGA) were used. R version. 4.0.3 and multiple databases (TIMER, cBioportal, gene expression profile interaction analysis [GEPIA], LinkedOmics, and CancerSEA) were utilized to investigate mRNA expression, mutational analysis, prognosis, clinical correlations, co-expressed gene, pathway and network, and single-cell analyses. Immunohistochemistry (IHC) confirmed that E2F transcription factor 7 (E2F7) correlated with LUAD. Among the E2Fs, E2F7 was identified by constructing a prognostic model most significantly associated with overall survival (OS) in LUAD patients. The univariate and multivariate Cox regression analyses showed that E2F7, p-T stage, and p-TNM stage were closely related to OS and progression-free survival (PFS) (P < .05) in LUAD. E2F 7/8 were also identified as significantly associated with tumor stage in the GEPIA database. Compared with paracancerous tissues, E2F7 was up-regulated in LUAD by IHC, and E2F7 might be positively correlated with larger tumors and higher TNM stages. E2F7 may primarily regulate DNA repair, damage, and cell cycle processes and thus affect LUAD tumorigenesis, invasion, and metastasis by LinkedOmics and CancerSEA. E2F7 serves as a potential prognostic biomarker for LUAD.

Progress and challenges of plant-derived nucleic acids as therapeutics in macrophage-mediated RNA therapy.

Plant-derived nucleic acids, especially small RNAs have been proved by increasing evidence in the pharmacological activities and disease treatment values in macrophage meditated anti-tumor performance, immune regulating functions and antiviral activities. But the uptake, application and delivery strategies of RNAs as biodrugs are different from the small molecules and recombinant protein drugs. This article summarizes the reported evidence for cross-kingdom regulation by plant derived functional mRNAs and miRNAs. Based on that, their involvement and potentials in macrophage-mediated anti-tumor/inflammatory therapies are mainly discussed, as well as the load prospect of plant RNAs in viruses and natural exosome vehicles, and their delivery to mammalian cells through macrophage were also summarized. This review is to provide evidence and views for the plant derived RNAs as next generation of drugs with application potential in nucleic acid-based bio-therapy.

Spectroscopic and Simulation Insights into the Corrosion Mechanism of Sulfite on Titanium.

Ion adsorption and hydrogen bond (HB) network reconstruction in electric double layer (EDL) have a profound impact on the interface properties. The microstructure in the bulk phase of 1.00-21.30 wt.% Na2SO3 aqueous solutions are investigated by X-ray scattering, confocal Raman spectroscopy, and classical molecular dynamics. The electronic properties of SO32- adsorption and the geometric structure of the HB network in the EDL at the titanium TiO2(101) surface are studied by density functional theory (DFT) and classical molecular dynamics. The SO32- strongly weakens the fully hydrogen-bonded water (FHW) and transforms it into partial hydrogen-bonded water (PHW). The HB transformation index (HBTI = PHW/FHW) shows a linear relationship with the mass fraction of Na2SO3. The TiOb-parallel adsorption configuration of SO32- enhances the ionicity of the Ob-Ti6 bond, resulting in the formation of oxygen vacancies at the titanium passive film surface. Besides, SO32- and Na+ are enriched and thermodynamic supersaturated in the inner Helmholtz layer (IHL), and the ions are diluted in the outer Helmholtz layer (OHL). The diffusion coefficient of SO32- and water molecules in EDL decreases seriously, which is easy to causes salt scaling on the surface of titanium passive film. This work provides evidence for the destruction of titanium passive film by SO32-.

The major leaf ferredoxin Fd2 regulates plant innate immunity in Arabidopsis.

Ferredoxins, the major distributors for electrons to various acceptor systems in plastids, contribute to redox regulation and antioxidant defence in plants. However, their function in plant immunity is not fully understood. In this study, we show that the expression of the major leaf ferredoxin gene Fd2 is suppressed by Pseudomonas syringae pv. tomato (Pst) DC3000 infection, and that knockout of Fd2 (Fd2-KO) in Arabidopsis increases the plant's susceptibility to both Pst DC3000 and Golovinomyces cichoracearum. On Pst DC3000 infection, the Fd2-KO mutant accumulates increased levels of jasmonic acid and displays compromised salicylic acid-related immune responses. Fd2-KO also shows defects in the accumulation of reactive oxygen species induced by pathogen-associated molecular pattern-triggered immunity. However, Fd2-KO shows enhanced R-protein-mediated resistance to Pst DC3000/AvrRpt2 infection, suggesting that Fd2 plays a negative role in effector-triggered immunity. Furthermore, Fd2 interacts with FIBRILLIN4 (FIB4), a harpin-binding protein localized in chloroplasts. Interestingly, Fd2, but not FIB4, localizes to stromules that extend from chloroplasts. Taken together, our results demonstrate that Fd2 plays an important role in plant immunity.

Synthesis, crystal structures and antitumor activity of two platinum(II) complexes with methyl hydrazinecarbodithioate derivatives of indolin-2-one.

Two new platinum(II) complexes 7a and 7b with methyl hydrazinecarbodithioate derivatives of indolin-2-one have been prepared and characterized by single-crystal X-ray diffraction, NMR spectroscopy and mass spectrometry. Antiproliferative activity of the two complexes and their ligands 6a and 6b against HCT-116, MCF-7 and MDA-MB-231 cell lines was determined by the MTS assay. Complexes 7a and 7b exhibited stronger antiproliferative activity against three cell lines than compounds 6a and 6b (IC50, 1.89-5.60 versus 6.52-35.13 µM). Moreover, treatment of HCT-116 cells with the complexes resulted in an obvious sub-G1 peak by cell cycle profile analysis, and an increase of cleaved PARP1 and caspases 3, 7, and 9 by immunoblotting analysis. Live cell imaging showed that nucleus shrinkage and condensation started to appear when MCF-7 cells were treated with 7a for 8 h. Fluorescent spectrophotometric analysis revealed that the complexes physically associated with calf thymus DNA. Competitive DNA binding assays uncovered that the complexes non-covalently bind to DNA. Taken together, our results indicated that the two new platinum(II) complexes 7a and 7b non-covalently bind to DNA with high affinity and exhibit cytotoxicity against cancer cells by inducing apoptosis.

BSK1, a receptor-like cytoplasmic kinase, involved in both BR signaling and innate immunity in Arabidopsis.

Molecular interaction between powdery mildew fungi and Arabidopsis has been widely used as a model system to study plant immunity. Arabidopsis EDR2 (enhanced disease resistance 2) is a well characterized negative regulator in powdery mildew resistance and mildew-induced cell death. Recently, we showed that a mutation in BSK1 (br-signaling kinase 1), suppressed edr2-mediated disease resistance. (1) And the bsk1-1 single mutant displayed enhanced susceptibility to multiple pathogens, indicating that BSK1 plays important roles in plant immunity. BSK1 is a receptor-like cytoplasmic kinase and localizes on plasma membrane; loss of the membrane localization signaling disrupts BSK1 functions in edr2-mediated resistance. Significantly, BSK1 physically associates with the PAMP receptor FLS2 (flagellin sensing 2) and is required by FLS2-mediated ROS burst. (1) Here we show that disruption of BSK1 membrane localization affects the BSK1-FLS2 interactions, suggesting the membrane association of BSK1 is important for both edr2-mediated signaling and the BSK1-FLS2 complex formation. Previously, it was shown that BSK1 is a substrate of the brassinosteroid (BR) receptor BRI1 (brassinosteroid insensitive 1) and plays critical roles in BR signaling. (2) Further exploration of signaling transductions downstream of BSK1-FLS2 complex will not only shed new light on how BSK1 regulates plant immunity, but may also help to dissect the connections between plant growth and defense.