Characterization and heterologous reconstitution of Taxus biosynthetic enzymes leading to baccatin III

Paclitaxel is a well known anticancer compound. Its biosynthesis involves the formation of a highly functionalized diterpenoid core skeleton (baccatin III) and the subsequent assembly of a phenylisoserinoyl side chain. Despite intensive investigation for half a century, the complete biosynthetic pathway of baccatin III remains unknown. In this work, we identified a bifunctional cytochrome P450 enzyme [taxane oxetanase 1 (TOT1)] in Taxus mairei that catalyzes an oxidative rearrangement in paclitaxel oxetane formation, which represents a previously unknown enzyme mechanism for oxetane ring formation. We created a screening strategy based on the taxusin biosynthesis pathway and uncovered the enzyme responsible for the taxane oxidation of the C9 position (T9αH1). Finally, we artificially reconstituted a biosynthetic pathway for the production of baccatin III in tobacco.

Comparison of Pulmonary and Extrapulmonary Models of Sepsis-Associated Acute Lung Injury

To compare different rat models of sepsis at different time points, based on pulmonary or extrapulmonary injury mechanisms, to identify a model which is more stable and reproducible to cause sepsis-associated acute lung injury (ALI). Adult male Sprague-Dawley rats were subjected to (1) cecal ligation and puncture (CLP) with single (CLP1 group) or two repeated through-and-through punctures (CLP2 group); (2) tail vein injection with lipopolysaccharide (LPS) of 10mg/kg (IV-LPS10 group) or 20 mg/kg (IV-LPS20 group); (3) intratracheal instillation with LPS of 10mg/kg (IT-LPS10 group) or 20mg/kg (IT-LPS20 group). Each of the model groups had a sham group. 7-day survival rates of each group were observed (n=15 for each group). Moreover, three time points were set for additional experimental studying in each model group: 4 hours, 24 hours and 48 hours after modeling (every time point, n=8 for each group). Rats were sacrificed to collect BALF and lung tissue samples at different time points for detection of IL-6, TNF-alpha, total protein concentration in BALF and MPO activity, HMGB1 protein expression in lung tissues, as well as the histopathological changes of lung tissues. More than 50 % of the rats died within 7 days in each model group, except for the IT-LPS10 group. In contrast, the mortality rates in the two IV-LPS groups as well as the IT-LPS20 group were significantly higher than that in IT-LPS10 group. Rats received LPS by intratracheal instillation exhibited evident histopathological changes and inflammatory exudation in the lung, but there was no evidence of lung injury in CLP and IV-LPS groups. Rat model of intratracheal instillation with LPS proved to be a more stable and reproducible animal model to cause sepsis-associated ALI than the extrapulmonary models of sepsis.

Investigations of clinical characteristics and inflammatory markers of febrile seizures induced by coronavirus infection

The study of children who experienced with febrile seizures(FS) as a result of COVID-19 infection to gain insight into the clinical characteristics and prognosis of neurological damage, with the aim of improving prevention, diagnosis, and the treatment of neurological complications. This study investigated the clinical features of 53 children with FS who were admitted to Sanya Women and Children's Hospital from December 1, 2022, to January 31, 2023. The results indicated that the duration of convulsion in the case and control group was 7.90±8.91 and 2.67±1.23 (minutes) respectively. The analysis reveals that convulsions occurred within 24 hours in 39 cases (95.12%) of the case group, and in 8 cases (66.7%) of the control group. The difference was statistically significant (P<0.05). Additionally, the case group presented lower counts of WBC and NEU compared to the control group (p<0.05). The findings indicate that convulsions manifest at earlier stages of COVID-19 in children and the last longer than in the control group. It is therefore crucial for healthcare workers to remain attentive to patients with COVID-19 who report fever within 24 hours, and act promptly to implement preventive measures, particularly in cases of prolonged fever. It is essential to integrate the clinical manifestation, particularly convulsions, and the continuous numerical changes of inflammatory factors to assess COVID-19 linked with febrile seizures. In addition, larger-scale multi-center and systematic research are necessary to aid clinicians in monitoring neuropathological signals and biological targets, enabling more equitable diagnosis and treatment plans.

Fermented rape pollen powder can alleviate benign prostatic hyperplasia in rats by reducing hormone content and changing gut microbiota

Benign prostatic hyperplasia (BPH) can cause urethral compression, bladder stone formation, and renal function damage, which may endanger the life of patients. Therefore, we aimed to develop plant-based preparations for BPH treatment with no side effects. In this study, the Lactiplantibacillus plantarum 322Hp, Lactobacillus acidophilus 322Ha, and Limosilactobacillus reuteri 322Hr were used to ferment rape pollen. The fermented rape pollen was subsequently converted into fermented rape pollen powder (FRPP) through vacuum freeze-drying technology. After fermenting and drying, the bioactive substances and antioxidant capacity of FRPP were significantly higher than those of unfermented rapeseed pollen, and FRPP had a longer storage duration, which can be stored for over one year. To investigate the therapeutic effect of FRPP on BPH, a BPH rat model was established by hypodermic injection of testosterone propionate. The BPH rats were treated differently, with the model group receiving normal saline, the positive control group receiving finasteride, and the low, medium, and high dose FRPP group receiving FRPP at doses of 0.14 g/kg/d, 0.28 g/kg/d, and 0.56 g/kg/d, respectively. The results indicate that medium dose FRPP reduced the levels of hormone such as testosterone, dihydrotestosterone, and oestradiol in rats with BPH by about 32%, thus bringing the prostate tissue of BPH rats closer to normal. More importantly, medium dose FRPP treatment had a significant effect on the composition of gut microbiota in rats with BPH, increasing the levels of beneficial genera (such as Coprococcus and Jeotgalicoccus), and decreasing the levels of harmful pathogens (such as Turicibacter and Clostridiaceae_Clostridium) in the gut. This study showed that medium dose FRPP reduced the hormone level and regulated the unbalanced gut microbiota in BPH rats, thereby alleviating BPH.

Multi-dimensional radiomics analysis to predict visceral pleural invasion in lung adenocarcinoma of ≤3 cm maximum diameter

AIM

To explore the value of radiomics analysis in preoperatively predicting visceral pleural invasion (VPI) of lung adenocarcinoma (LAC) with ≤3 cm maximum diameter and to compare the performance of two-dimensional (2D) and three-dimensional (3D) computed tomography (CT) radiomics models.

MATERIALS AND METHODS

A total of 391 LAC patients were enrolled retrospectively, of whom 142 were VPI (+) and 249 were VPI (-). Radiomics features were extracted from 2D and 3D regions of interest (ROIs) of tumours in CT images. 2D and 3D radiomics models were developed combining the optimal radiomics features by using the logistic regression machine-learning method and radiomics scores (rad-scores) were calculated. Nomograms were constructed by integrating independent risk factors and rad-scores. The performance of each model was evaluated by using the receiver operator characteristic (ROC) curve, decision curve analysis (DCA), clinical impact curve (CIC), and calculating the area under the curve (AUC).

RESULTS

There was no difference in the VPI prediction between 2D and 3D radiomics models (training group: 2D AUC=0.835, 3D AUC=0.836, p=0.896; validation group: 2D AUC=0.803, 3D AUC=0.794, p=0.567). The 2D and 3D nomograms performed similarly regarding discrimination (training group: 2D AUC=0.867, 3D AUC=0.862, p=0.409, validation group: 2D AUC=0.835, 3D AUC=0.827, p=0.558), and outperformed their corresponding radiomics models and the clinical model. DCA and CIC revealed that the 2D nomogram had slightly better clinical utility.

CONCLUSION

The 2D radiomics model has a similar discrimination capability compared with the 3D radiomics model. The 2D nomogram performs slightly better for individual VPI prediction in LAC.

VA-TIRFM-based SM kymograph analysis for dwell time and colocalization of plasma membrane protein in plant cells

BACKGROUND

The plasma membrane (PM) proteins function in a highly dynamic state, including protein trafficking and protein homeostasis, to regulate various biological processes. The dwell time and colocalization of PM proteins are considered to be two important dynamic features determining endocytosis and protein interactions, respectively. Dwell-time and colocalization detected using traditional fluorescence microscope techniques are often misestimated due to bulk measurement. In particular, analyzing these two features of PM proteins at the single-molecule level with spatiotemporal continuity in plant cells remains greatly challenging.

RESULTS

We developed a single molecular (SM) kymograph method, which is based on variable angle-total internal reflection fluorescence microscopy (VA-TIRFM) observation and single-particle (co-)tracking (SPT) analysis, to accurately analyze the dwell time and colocalization of PM proteins in a spatial and temporal manner. Furthermore, we selected two PM proteins with distinct dynamic behaviors, including AtRGS1 (Arabidopsis regulator of G protein signaling 1) and AtREM1.3 (Arabidopsis remorin 1.3), to analyze their dwell time and colocalization upon jasmonate (JA) treatment by SM kymography. First, we established new 3D (2D+t) images to view all trajectories of the interest protein by rotating these images, and then we chose the appropriate point without changing the trajectory for further analysis. Upon JA treatment, the path lines of AtRGS1-YFP appeared curved and short, while the horizontal lines of mCherry-AtREM1.3 demonstrated limited changes, indicating that JA might initiate the endocytosis of AtRGS1. Analysis of transgenic seedlings coexpressing AtRGS1-YFP/mCherry-AtREM1.3 revealed that JA induces a change in the trajectory of AtRGS1-YFP, which then merges into the kymography line of mCherry-AtREM1.3, implying that JA increases the colocalization degree between AtRGS1 and AtREM1.3 on the PM. These results illustrate that different types of PM proteins exhibit specific dynamic features in line with their corresponding functions.

CONCLUSIONS

The SM-kymograph method provides new insight into quantitively analyzing the dwell time and correlation degree of PM proteins at the single-molecule level in living plant cells.

OsMADS17 simultaneously increases grain number and grain weight in rice

During the processes of rice domestication and improvement, a trade-off effect between grain number and grain weight was a major obstacle for increasing yield. Here, we identify a critical gene COG1, encoding the transcription factor OsMADS17, with a 65-bp deletion in the 5' untranslated region (5' UTR) presented in cultivated rice increasing grain number and grain weight simultaneously through decreasing mRNA translation efficiency. OsMADS17 controls grain yield by regulating multiple genes and that the interaction with one of them, OsAP2-39, has been characterized. Besides, the expression of OsMADS17 is regulated by OsMADS1 directly. It indicates that OsMADS1-OsMADS17-OsAP2-39 participates in the regulatory network controlling grain yield, and downregulation of OsMADS17 or OsAP2-39 expression can further improve grain yield by simultaneously increasing grain number and grain weight. Our findings provide insights into understanding the molecular basis co-regulating rice yield-related traits, and offer a strategy for breeding higher-yielding rice varieties.

Physiological and transcriptomic analysis reveal the regulatory mechanism underlying grain quality improvement induced by rice ratooning

BACKGROUND

Ratoon rice cropping has been introduced for increased rice production in southern China and, as a result, has been becoming increasingly popular. However, only a few studies have addressed the regulatory mechanism underlying grain quality improvement induced by rice ratooning.

RESULTS

In this study, parameters of rice quality, including head rice yield, chalky grain percentage, grain chalkiness degree, hardness and taste value, were shown to be much improved in the ratooning season rice as compared to its counterparts main and late cropping season rice, indicating that such an improvement was irrespective of seasonal effects. In addition, the nutritional components of grains varied greatly between main-cropping season rice, ratooning season rice and late-cropping season rice and displayed a significant correlation with rice quality. Finally, the regulatory mechanism underlying rice quality improvement revealed that gibberellin-dominated regulation and plant hormone signal transduction jointly contributed to a decrease in formation of chalky grains.

CONCLUSION

This work improves our knowledge on rice quality improvement under rice ratooning, particularly on the regulatory mechanism of plant hormones. © 2022 Society of Chemical Industry.

DWI-Based Radiomics Predicts the Functional Outcome of Endovascular Treatment in Acute Basilar Artery Occlusion

BACKGROUND AND PURPOSE

Endovascular treatment is a reference treatment for acute basilar artery occlusion (ABAO). However, no established and specific methods are available for the preoperative screening of patients with ABAO suitable for endovascular treatment. This study explores the potential value of DWI-based radiomics in predicting the functional outcomes of endovascular treatment in ABAO.

MATERIALS AND METHODS

Patients with ABAO treated with endovascular treatment from the BASILAR registry (91 patients in the training cohort) and the hospitals in the Northwest of China (31 patients for the external testing cohort) were included in this study. The Mann-Whitney U test, random forests algorithm, and least absolute shrinkage and selection operator were used to reduce the feature dimension. A machine learning model was developed on the basis of the training cohort to predict the prognosis of endovascular treatment. The performance of the model was evaluated on the independent external testing cohort.

RESULTS

A subset of radiomics features (n = 6) was used to predict the functional outcomes in patients with ABAO. The areas under the receiver operating characteristic curve of the radiomics model were 0.870 and 0.781 in the training cohort and testing cohort, respectively. The accuracy of the radiomics model was 77.4%, with a sensitivity of 78.9%, specificity of 75%, positive predictive value of 83.3%, and negative predictive value of 69.2% in the testing cohort.

CONCLUSIONS

DWI-based radiomics can predict the prognosis of endovascular treatment in patients with ABAO, hence allowing a potentially better selection of patients who are most likely to benefit from this treatment.

Phase separation of nuclear pore complex facilitates selective nuclear transport to regulate plant defense against pathogen and pest invasion

Nuclear pore complex (NPC), the sole exchange channel between nucleus and cytoplasm, is composed of several subcomplexes, among which, the central barrier determines the permeability/selectivity of NPC to dominate the nucleocytoplasmic trafficking essential for many important signaling events in yeast and mammals. How plant NPC central barrier controls selective transport is a crucial question remaining to be elucidated. Here, we uncovered that phase separation of the central barrier is critical for the permeability and selectivity of plant NPC to regulate various biotic stresses. Phenotypic assay of nup62 mutants and complementary lines showed that NUP62 positively regulates plant defense to Botrytis cinerea, one of the world's most disastrous plant pathogens. Furthermore, both in vivo imaging and in vitro biochemical evidence revealed that plant NPC central barrier undergoes phase separation to regulate selective nucleocytoplasmic transport of immune regulators, as exemplified by MPK3 essential for plant resistance to Botrytis cinerea. Moreover, genetic analysis demonstrated that NPC phase separation plays an important role in plant defense against fungal and bacterial infection as well as insect attack. These findings reveal that phase separation of the NPC central barrier serves as an important mechanism to mediate nucleocytoplasmic transport of immune regulators and activate plant defense against a broad range of biotic stresses.

Jasmonate-based warfare between the pathogenic intruder and host plant: who wins?

Plants and microbial pathogens often engage in a fierce war that determines their survival. Host plants have evolved sophisticated regulatory mechanisms to fine-tune defense responses to counter attacks from pathogens, while pathogens often hijack the lipid-derived phytohormone jasmonate to cause hormonal signaling imbalances for efficient infection. This review focuses on the jasmonate-based warfare between host plants and pathogenic intruders, and further discusses approaches to uncouple plant growth and defense tradeoffs in crop breeding.

GF14f gene is negatively associated with yield and grain chalkiness under rice ratooning

BACKGROUND

Ratoon rice cropping has been shown to provide new insights into overcoming the current challenges of rice production in southern China. However, the potential mechanisms impacting yield and grain quality under rice ratooning remain unclear.

METHODS

In this study, changes in yield performance and distinct improvements in grain chalkiness in ratoon rice were thoroughly investigated, using physiological, molecular and transcriptomic analysis.

RESULTS

Rice ratooning induced an extensive carbon reserve remobilization in combination with an impact on grain filling, starch biosynthesis, and ultimately, an optimization in starch composition and structure in the endosperm. Furthermore, these variations were shown to be associated with a protein-coding gene: GF14f (encoding GF14f isoform of 14-3-3 proteins) and such gene negatively impacts oxidative and environmental resistance in ratoon rice.

CONCLUSION

Our findings suggested that this genetic regulation by GF14f gene was the main cause leading to changes in rice yield and grain chalkiness improvement of ratoon rice, irrespective of seasonal or environmental effects. A further significance was to see how yield performance and grain quality of ratoon rice were able to be achieved at higher levels via suppression of GF14f.

Jasmonate perception: Ligand-receptor interaction, regulation, and evolution

Phytohormones integrate external environmental and developmental signals with internal cellular responses for plant survival and multiplication in changing surroundings. Jasmonate (JA), which might originate from prokaryotes and benefit plant terrestrial adaptation, is a vital phytohormone that regulates diverse developmental processes and defense responses against various environmental stresses. In this review, we first provide an overview of ligand-receptor binding techniques used for the characterization of phytohormone-receptor interactions, then introduce the identification of the receptor COI1 and active JA molecules, and finally summarize recent advances on the regulation of JA perception and its evolution.

Multi-vendor multi-site quantitative MRI analysis of cartilage degeneration 10 Years after anterior cruciate ligament reconstruction: MOON-MRI protocol and preliminary results

OBJECTIVE

To describe the protocol of a multi-vendor, multi-site quantitative MRI study for knee post-traumatic osteoarthritis (PTOA), and to present preliminary results of cartilage degeneration using MR T1ρ and T2 imaging 10 years after anterior cruciate ligament reconstruction (ACLR).

DESIGN

This study involves three sites and two MR platforms. The patients are from a nested cohort (termed as Onsite cohort) within the Multicenter Orthopaedic Outcomes Network (MOON) cohort 10 years after ACLR. Phantoms and controls were scanned for evaluating reproducibility. Cartilage was automatically segmented, and T1ρ and T2 were compared between operated, contralateral, and control knees.

RESULTS

Sixty-eight ACL-reconstructed patients and 20 healthy controls were included. In phantoms, the intra-site coefficients of variation (CVs) of repeated scans ranged 1.8-2.1% for T1ρ and 1.3-1.7% for T2. The inter-site CVs ranged 1.6-2.1% for T1ρ and 1.1-1.4% for T2. In human subjects, the intra-site scan/rescan CVs ranged 2.2-3.5% for T1ρ and 2.6-4.9% for T2 for the six major compartments. In patients, operated knees showed significantly higher T1ρ and T2 values mainly in medial femoral condyle, medial tibia and trochlear cartilage compared with contralateral knees, and showed significantly higer T1ρ and T2 values in all six compartments compared to healthy control knees. The patient contralateral knees showed higher T1ρ and T2 values mainly in the lateral femoral condyle, lateral tibia, trochlear, and patellar cartilage compared to healthy control knees.

CONCLUSION

A platform and workflow with rigorous quality control has been established for a multi-vendor multi-site quantitative MRI study in evaluating PTOA 10 years after ACLR. Our preliminary report suggests significant cartilage matrix changes in both operated and contralateral knees compared with healthy control knees.

Characteristics of vertical drop jump to screen the anterior cruciate ligament injury

OBJECTIVE

To clarify the characteristics of vertical drop jump (VDJ) for screening athletes at high risk of ACL injury by comparing the kinematic, kinetic and electromyographic variables of different VDJ.

SUBJECTS AND METHODS

Thirty male soccer players were recruited to measure parameters of knee kinematics, kinetics, and surface electromyograph during VDJ in four kinds of movements measured (the distance between the take-off feet is 5 cm or 30 cm, and the distance between the landing feet is 5 cm or 30 cm) using the Vicon motion capture system, Kistler3-D dynamometer, and Noraxon surface electromyograph test system.

RESULTS

The peak knee abduction moment was significantly greater for landing feet distance of 30 cm compared to landing feet distance of 5 cm, regardless of whether the distance between take-off feet was 5 cm (0.58 vs. 0.44) or 30 cm (0.61 vs. 0.40); regardless of whether the distance between landing feet was 5 cm (22.78 vs. 20.45) or 30 cm (24.32 vs. 21.87), the peak vertical Ground Reaction Force was significantly increased for the take-off feet distance was 5 cm compared to take-off feet of 30 cm.

CONCLUSIONS

In the test of VDJ, athletes will adopt different landing strategies for different movement instructions, and the VDJ with the distance of 5 cm between the take-off feet and the distance of 30 cm between the landing feet may be the better maneuver to screen for risk of ACL injury.

Aqueous construction of raspberry-like ZIF-8 hierarchical structures with enhanced superhydrophobic performance

Materials with super-wetting ability have attracted wide attention from both academia and industry due to their great potential applications. A straightforward and versatile route was proposed for the large-scale synthesis of a monodisperse raspberry-like metal-organic framework (ZIF-8) using zinc nitrate as a zinc source and dimethylimidazole as an organic ligand in aqueous solution. After hydrophobic treatment with hexadecyltrimethoxysilane, the ethanolic suspension of three-dimensional raspberry-like ZIF-8 showed excellent superhydrophobic properties. Furthermore, commercial adhesives were used to blend with the suspension to improve the bonding strength to different substrates. These surfaces retained their water resistance after 50 finger-wipe cycles, 40 sandpaper abrasions and knife scratches. Moreover, the prepared hydrophobic surface can withstand the impact of water flow for 10 minutes. The formulations developed can be used for superhydrophobic coating applications on different substrate surfaces such as aluminum foil, glass, paper and cotton.

Morphological classification and measurement of the glenoid cavity using three-dimensional reconstruction in a Chinese population

BACKGROUND

The purpose of this study was to examine the various shapes and record the morphometric data of the glenoid cavity in a Chinese population.

MATERIALS AND METHODS

A total of 501 scapulae, 247 left and 254 right, were analyzed. We classified the shape of the glenoid cavity as type Ⅰ (pear-shaped), type Ⅱ (oval-shaped), type Ⅲ (teardrop-shaped), type Ⅳ (calabash-shaped) or type Ⅴ (inverted comma-shaped). Four defined parameters, the superior-inferior glenoid diameter (AB), upper anterior-posterior glenoid diameter (CD), lower anterior-posterior glenoid diameter (EF) and glenoid index (GI), were measured, and five shapes were classified via three-dimensional reconstruction.

RESULTS

The mean AB, CD, EF and GI values of the glenoid were 3.51±0.41 cm, 1.95±0.28 cm, 2.60±0.34 cm, and 1.35±0.12 cm, respectively. The AB value of type Ⅱ glenoid cavities was significantly smaller than that of type Ⅰ and Ⅲ glenoid cavities (P<0.05), but the GI value of type Ⅱ glenoid cavities was larger than that of type Ⅲ cavities (P<0.05). The CD value showed a difference between type Ⅰ and type Ⅲ glenoid cavities (P<0.05). For the EF parameter, the values of type Ⅲ glenoid cavities were significantly larger than those of type Ⅰ and Ⅱ glenoid cavities (P<0.05).

CONCLUSIONS

Measuring and observing the variety of shapes and sizes of the glenoid cavity in Chinese people is conducive to for better understand its morphological features. This information can also guide surgeons in the design and selection of suitable prostheses for total shoulder arthroplasty in the Chinese population in order to reduce postoperative complications.

Rice functional genomics: decades' efforts and roads ahead

Rice (Oryza sativa L.) is one of the most important crops in the world. Since the completion of rice reference genome sequences, tremendous progress has been achieved in understanding the molecular mechanisms on various rice traits and dissecting the underlying regulatory networks. In this review, we summarize the research progress of rice biology over past decades, including omics, genome-wide association study, phytohormone action, nutrient use, biotic and abiotic responses, photoperiodic flowering, and reproductive development (fertility and sterility). For the roads ahead, cutting-edge technologies such as new genomics methods, high-throughput phenotyping platforms, precise genome-editing tools, environmental microbiome optimization, and synthetic methods will further extend our understanding of unsolved molecular biology questions in rice, and facilitate integrations of the knowledge for agricultural applications.

Isoleucine Enhances Plant Resistance Against Botrytis cinerea via Jasmonate Signaling Pathway

Amino acids are the building blocks of biomacromolecules in organisms, among which isoleucine (Ile) is the precursor of JA-Ile, an active molecule of phytohormone jasmonate (JA). JA is essential for diverse plant defense responses against biotic and abiotic stresses. Botrytis cinerea is a necrotrophic nutritional fungal pathogen that causes the second most severe plant fungal disease worldwide and infects more than 200 kinds of monocot and dicot plant species. In this study, we demonstrated that Ile application enhances plant resistance against B. cinerea in Arabidopsis, which is dependent on the JA receptor COI1 and the jasmonic acid-amido synthetase JAR1. The mutant lib with higher Ile content in leaves exhibits enhanced resistance to B. cinerea infection. Furthermore, we found that the exogenous Ile application moderately enhanced plant resistance to B. cinerea in various horticultural plant species, including lettuce, rose, and strawberry, suggesting a practical and effective strategy to control B. cinerea disease in agriculture. These results together showed that the increase of Ile could positively regulate the resistance of various plants to B. cinerea by enhancing JA signaling, which would offer potential applications for crop protection.

Strigolactone mimic 2-nitrodebranone is highly active in Arabidopsis growth and development

Strigolactones play crucial roles in regulating plant architecture and development, as endogenous hormones, and orchestrating symbiotic interactions with fungi and parasitic plants, as components of root exudates. rac-GR24 is currently the most widely used strigolactone analog and serves as a reference compound in investigating the action of strigolactones. In this study, we evaluated a suite of debranones and found that 2-nitrodebranone (2NOD) exhibited higher biological activity than rac-GR24 in various aspects of plant growth and development in Arabidopsis, including hypocotyl elongation inhibition, root hair promotion and senescence acceleration. The enhanced activity of 2NOD in promoting AtD14-SMXL7 and AtD14-MAX2 interactions indicates that the molecular structure of 2NOD is a better match for the ligand perception site pocket of D14. Moreover, 2NOD showed lower activity than rac-GR24 in promoting Orobanche cumana seed germination, suggesting its higher ability to control plant architecture than parasitic interactions. In combination with the improved stability of 2NOD, these results demonstrate that 2NOD is a strigolactone analog that can specifically mimic the activity of strigolactones and that 2NOD exhibits strong potential as a tool for studying the strigolactone signaling pathway in plants.

Helix B surface peptide protects against acute lung injury through reducing oxidative stress and endoplasmic reticulum stress via activation of Nrf2/HO-1 signaling pathway

OBJECTIVE

Acute lung injury (ALI) is a clinical problem with poor prognosis and high mortality. The purpose of this study was to explore the effects of helix B position peptide (HBSP) on ALI and its mechanism.

MATERIALS AND METHODS

C57/BL6 male mice were used to construct ALI models by LPS tracheal injection and detect the effect of HBSP on mouse ALI by subcutaneously injecting HBSP. In addition, normal human lung epithelial cell line (BEAS-2B) were cultured and stimulated with HBSP. Then, the effects of HBSP on oxidative stress and endoplasmic reticulum stress (ERS) in BEAS-2B cells were examined. Finally, the effect of HBSP on the Nrf2/HO-1 signaling pathway was examined, and the mechanism of action of HBSP was verified using the Nrf2/HO-1 signaling pathway inhibitor ML385.

RESULTS

In vitro, HBSP increased the expression of SOD1/2 and decreased the expression of ERS-related molecules such as CHOP, GRP-78, and caspase-12, indicating that HBSP effectively reduces the level of oxidative stress and ERS in BEAS-2B cells. In addition, HBSP also increased the activity of the Nrf2/HO-1 signaling pathway and ML385 reduced the protective effect of HBSP on BEAS-2B cells. In vivo, HBSP significantly reduced LPS-induced mouse ALI. W/D and inflammatory factors in the BALF of the mouse lung were significantly reduced and the level of oxidative stress was also reduced.

CONCLUSIONS

HBSP plays an important role in relieving ALI by activating Nrf2/HO-1 signaling pathway, which reduces the level of inflammation in lung tissue and oxidative stress and ERS in lung epithelial cells.

Molecular basis for high ligand sensitivity and selectivity of strigolactone receptors in Striga

Seeds of the root parasitic plant Striga hermonthica can sense very low concentrations of strigolactones (SLs) exuded from host roots. The S. hermonthica hyposensitive to light (ShHTL) proteins are putative SL receptors, among which ShHTL7 reportedly confers sensitivity to picomolar levels of SL when expressed in Arabidopsis thaliana. However, the molecular mechanism underlying ShHTL7 sensitivity is unknown. Here we determined the ShHTL7 crystal structure and quantified its interactions with various SLs and key interacting proteins. We established that ShHTL7 has an active-site pocket with broad-spectrum response to different SLs and moderate affinity. However, in contrast to other ShHTLs, we observed particularly high affinity of ShHTL7 for F-box protein AtMAX2. Furthermore, ShHTL7 interacted with AtMAX2 and with transcriptional regulator AtSMAX1 in response to nanomolar SL concentration. ShHTL7 mutagenesis analyses identified surface residues that contribute to its high-affinity binding to AtMAX2 and residues in the ligand binding pocket that confer broad-spectrum response to SLs with various structures. Crucially, yeast-three hybrid experiments showed that AtMAX2 confers responsiveness of the ShHTL7-AtSMAX1 interaction to picomolar levels of SL in line with the previously reported physiological sensitivity. These findings highlight the key role of SL-induced MAX2-ShHTL7-SMAX1 complex formation in determining the sensitivity to SL. Moreover, these data suggest a strategy to screen for compounds that could promote suicidal seed germination at physiologically relevant levels.

HbCOI1 perceives jasmonate to trigger signal transduction in Hevea brasiliensis

Natural rubber, a strategically essential raw material used in manufacturing throughout the world, is produced from coagulated and refined latex of rubber tree (Hevea brasiliensis). It is known that phytohormone jasmonate (JA) plays an essential role in regulating latex biosynthesis. However, it is unclear how the JA signal is sensed in a rubber tree. Here, we showed that H. brasiliensis CORONATINE-INSENSITIVE 1 (HbCOI1) acts as a receptor that perceives JA to recruit H. brasiliensis JASMONATE ZIM DOMAIN1 (HbJAZ1) for signal transduction. We found that HbCOI1 restores male sterility and JA responses of the coi1-1 mutant in Arabidopsis. The identification of a JA receptor in the rubber tree is essential for elucidating the molecular mechanisms underlying JA-regulated latex biosynthesis. Our results elucidate the mechanism of JA perception in H. brasiliensis and also provide an efficient strategy to identify JA receptors in woody plants.

Liquid biopsy by combining 5-hydroxymethylcytosine signatures of plasma cell-free DNA and protein biomarkers for diagnosis and prognosis of hepatocellular carcinoma

BACKGROUND

Liquid biopsy based on 5-hydroxymethylcytosine (5hmC) signatures of plasma cell-free DNA (cfDNA) originating from tumor cells provides a novel approach for early diagnosis in hepatocellular carcinoma (HCC). Here, we sought to develop a reliable model using cfDNA 5hmC signatures and protein biomarkers for diagnosis and prognosis of HCC.

PATIENTS AND METHODS

We carried out genome-wide 5hmC sequencing of cfDNA samples collected from 165 healthy volunteers, 62 liver cirrhosis (LC) patients and 135 HCC patients. A sensitive 5hmC diagnostic model was developed based on 5hmC signatures selected by sparse Partial Least Squares Discriminant Analysis and cross-validation to define the weighted diagnostic score (wd-score). Then, we combined protein biomarkers with the wd-score to build a more robust score (HCC score) by logistic regression.

RESULTS

The distribution pattern of differential 5hmC regions could clearly distinguish HCC patients, LC patients and healthy volunteers. The wd-score based on 64 5hmC signatures in cfDNA achieves 93.24% of area under the curve (AUC) to distinguish HCC patients from non-HCC patients, and the HCC score by combing protein biomarkers achieves 92.75% of AUC to distinguish HCC patients from LC patients. Meanwhile, the HCC score showed high capacity for screening high recurrence risk patients after receiving surgical resection, and appeared to be an independent indicator for both relapse-free survival (P = 0.00865) and overall survival (P = 0.000739). Furthermore, the values of the HCC score in patients' longitudinal plasma samples were positively associated with tumor burden dynamics during follow-up.

CONCLUSION

We have developed and validated a novel non-invasive liquid biopsy strategy for HCC diagnosis, prognosis and surveillance during HCC progression.

Horizontal orientation of zygomorphic flowers: significance for rain protection and pollen transfer

Floral traits are recognized to have evolved under selection for abiotic and biotic factors. Complex zygomorphic flowers usually face horizontally. It has been proved that a horizontal orientation facilitates pollinator recognition and pollination efficiency, but its significance in adaptation to abiotic factors remains unknown. The floral orientation of Abelia × grandiflora naturally varies around horizontal (with an angle of -30 to +33° between the floral main axis and the horizontal). We examined whether three different floral orientations affected flower thermal conditions, response to rain and pollination. Results showed that floral orientation had no effect on diurnal variations in flower temperature. The anthers of all three flower orientations were wetted by rainfall, but the inclined upward-facing flowers contained significantly more rainwater. The horizontal flowers received significantly higher visitation by hawkmoths and had a higher stigmatic pollen load. In contrast, the upward flower orientation reduced pollination precision, while downward-facing flowers had decreased pollinator attraction. This study indicates that horizontal flowers may have evolved as a trade-off between rain protection and pollination. Zygomorphic flowers that deviate from a horizontal orientation may have lower fitness because of flower flooding by rainwater and decreased pollen transfer.

The Ca2+ -regulated protein kinase CIPK1 integrates plant responses to phosphate deficiency in Arabidopsis thaliana

Phosphate (Pi) deficiency severely restricts plant growth and development, as Pi is an essential macronutrient. Calcium (Ca²⁺ ) is a ubiquitous second messenger in plants; calcineurin B-like proteins (CBL) and CBL-interacting protein kinases (CIPK) are signalling pathways that act as an important Ca²⁺ signalling network which integrates plants to fine tune the response to stress; however, whether CIPK are involved in Pi deficiency stress remains largely unknown. In this study, we carried out a reverse genetic strategy to screen T-DNA insertion mutants of CIPK isoforms under Pi deficiency in Arabidopsis thaliana. Then Pi content, transcription of phosphate starvation-induced (PSI) genes, acid phosphatase activity and hydrogen peroxide were determined in the wild-type (WT) and cipk1 mutant, respectively. The phenotype of CIPK1 complementation lines was analysed. The cipk1 mutant had a more sensitive phenotype, with lower root elongation and root length, and decreased Pi content compared with the WT under Pi deficiency. Moreover, CIPK1 mutation caused phosphate starvation-induced (PSI) genes to be significantly induced under Pi deficiency. Histological staining demonstrated that the cipk1 mutant had increased acid phosphatase activity and hydrogen peroxide concentration under Pi deficiency. By using the yeast two-hybrid system, we further demonstrated the interaction between CIPK1 and the WRKY transcription factors, WRKY6 and WRKY42. Overall, we demonstrate that CIPK1 is involved in the Pi deficiency signalling pathway in A. thaliana, revealing the important role of Ca²⁺ in the Pi nutrition signalling pathway, and potentially providing a theoretical foundation for molecular breeding of crops with better Pi utilization efficiency.

A Food and Drug Administration analysis of survival outcomes comparing the Adjuvant Paclitaxel and Trastuzumab trial with an external control from historical clinical trials

BACKGROUND

Although the Adjuvant Paclitaxel and Trastuzumab (APT) trial has been adopted clinically, single-arm trials have limitations, and interest remains whether these patients with small node-negative human epidermal growth factor receptor 2 (HER2)-positive early breast cancer (EBC) would benefit from more intensive chemotherapy. This analysis explored whether external controls can contextualize single-arm studies to add to clinical decision making in the use of de-escalated therapy in patients with low-risk HER2-positive EBC.

PATIENTS AND METHODS

Patient-level data from five randomized trials supporting drug approval in adjuvant HER2-positive EBC were pooled, and patients with low-risk EBC were selected (n = 1770). Patients treated concurrently with trastuzumab and either anthracycline/cyclophosphamide/taxane/trastuzumab (ACTH) or taxane/carboplatin/trastuzumab (TCH; n = 1366) were matched (1:1) to patients treated with paclitaxel and trastuzumab (TH) in the APT trial (n = 406) using propensity scores. Patients treated with anthracycline/cyclophosphamide/taxane (ACT; n = 374) were also matched (1:1) to those treated with TH. Propensity scores were estimated using covariates of age, tumor stage, estrogen receptor status, progesterone receptor status, and histological grade.

RESULTS

After matching, the estimated probabilities of invasive disease-free survival (iDFS) at 3 and 5 years were 98.6% and 96.5% in the TH arm, and 96.6% and 92.9% in the ACTH/TCH arm, respectively. The estimated probabilities of overall survival (OS) at 3 and 5 years were 99.7% and 99.3% in the TH arm, and 99.0% and 97.4% in the ACTH/TCH arm, respectively. Comparing the TH arm with the ACT arm in the matched sample, the estimated difference in iDFS was 7.5% (TH 98.8% and ACT 91.3%) at 3 years and 12.6% (TH 96.1% and ACT 83.5%) at 5 years. The estimated difference in OS was 2.6% (TH 100% and ACT 97.4%) at 3 years, and 5.3% (TH 99.3% and ACT 94.0%) at 5 years.

CONCLUSIONS

Our analyses suggest that patients' outcomes in both arms were in general similar, thus providing additional reassurance regarding de-escalation of therapy.

Light promotes jasmonate biosynthesis to regulate photomorphogenesis in Arabidopsis

Light acts as the pivotal external environment cue to modulate plant growth and development. Seeds germinate in the soil without light to undergo skotomorphogenesis with rapidly elongating hypocotyls that facilitate emergence from the soil, while seedlings upon light exposure undergo photomorphogenesis with significantly inhibited hypocotyl elongation that benefits plants to stand up firmly and cope with the changing environment. In this study, we demonstrate that light promotes jasmonate (JA) biosynthesis to inhibit hypocotyl elongation and orchestrate seedling photomorphogenesis in Arabidopsis. We showed that JAinhibition on hypocotyl elongation is dependent on JA receptor COI1 and signaling components such as repressor proteins JAZs and transcription activators MYC2/MYC3/MYC4. Furthermore, we found that MYC2/MYC3/MYC4 activate the expression of photomorphogenesis regulator HY5 to repress cell elongation-related genes (such as SAUR62 and EXP2) essential for seedling photomorphogenesis. Our findings provide a novel insight into molecular mechanisms underlying how plants integrate light signal with hormone pathway to establish seedling photomorphogenesis.

POSTAR2: deciphering the post-transcriptional regulatory logics

Post-transcriptional regulation of RNAs is critical to the diverse range of cellular processes. The volume of functional genomic data focusing on post-transcriptional regulation logics continues to grow in recent years. In the current database version, POSTAR2 (http://lulab.life.tsinghua.edu.cn/postar), we included the following new features and data: updated ∼500 CLIP-seq datasets (∼1200 CLIP-seq datasets in total) from six species, including human, mouse, fly, worm, Arabidopsis and yeast; added a new module ‘Translatome’, which is derived from Ribo-seq datasets and contains ∼36 million open reading frames (ORFs) in the genomes from the six species; updated and unified post-transcriptional regulation and variation data. Finally, we improved web interfaces for searching and visualizing protein–RNA interactions with multi-layer information. Meanwhile, we also merged our CLIPdb database into POSTAR2. POSTAR2 will help researchers investigate the post-transcriptional regulatory logics coordinated by RNA-binding proteins and translational landscape of cellular RNAs.

The DELLA proteins interact with MYB21 and MYB24 to regulate filament elongation in Arabidopsis

BACKGROUND

Gibberellin (GA) and jasmonate (JA) are two essential phytohormones for filament elongation in Arabidopsis. GA and JA trigger degradation of DELLAs and JASMONATE ZIM-domain (JAZ) proteins through SCF^SLY1 and SCF^COI1 separately to activate filament elongation. In JA pathway, JAZs interact with MYB21 and MYB24 to control filament elongation. However, little is known how DELLAs regulate filament elongation.

RESULTS

Here we showed that DELLAs interact with MYB21 and MYB24, and that R2R3 domains of MYB21 and MYB24 are responsible for interaction with DELLAs. Furthermore, we demonstrated that DELLA and JAZ proteins coordinately repress the transcriptional function of MYB21 and MYB24 to inhibit filament elongation.

CONCLUSION

We discovered that DELLAs interact with MYB21 and MYB24, and that DELLAs and JAZs attenuate the transcriptional function of MYB21 and MYB24 to control filament elongation. This study reveals a novel cross-talk mechanism of GA and JA in the regulation of filament elongation in Arabidopsis.

Jasmonate action in plant defense against insects

Herbivorous insects represent one of the major threats to sessile plants. To cope with herbivore challenges, plants have evolved sophisticated defense systems, in which the lipid-derived phytohormone jasmonate plays a crucial role. Perception of insect attack locally and systemically elicits rapid synthesis of jasmonate, which is perceived by the F-box protein COI1 to further recruit JAZ repressors for ubiquitination and degradation, thereby releasing transcription factors that subsequently activate plant defense against insect attack. Here, we review recent progress in understanding the molecular basis of jasmonate action in plant defense against insects.