A fast and high precision multi-robot environment modeling based on M-BFSI: Bidirectional filtering and scene identification method.

This article designs and implements a fast and high-precision multi-robot environment modeling method based on bidirectional filtering and scene identification. To solve the problem of feature tracking failure caused by large angle rotation, a bidirectional filtering mechanism is introduced to improve the error-matching elimination algorithm. A global key frame database for multiple robots is proposed based on a pretraining dictionary to convert images into a bag of words vectors. The images captured by different sub-robots are compared with the database for similarity score calculation, so as to realize fast identification and search of similar scenes. The coordinate transformation from local map to global map and the cooperative SLAM exploration of multiple robots is completed by the best matching image and the transformation matrix. The experimental results show that the proposed algorithm can effectively close the predicted trajectory of the sub-robot, thus achieving high-precision collaborative environment modeling.

Karst fissures mitigate the negative effects of drought on plant growth and photosynthetic physiology.

Hard limestone substrates, which are extensively distributed, are believed to exacerbate drought and increase the difficulty of restoration in vulnerable karst regions. Fissures in such substrates may alleviate the negative effect of drought on plants, but the underlying mechanisms remain poorly understood. In a two-way factorial block design, the growth and photosynthesis of 2-year-old Phoebe zhennan seedlings were investigated in two water availabilities (high versus low) and three stimulated fissure habitat groups (soil, soil-filled fissure and non-soil-filled fissure). Moreover, the fissure treatments included both small and big fissures. Compared to the soil group, the non-soil-filled fissure group had decreased the total biomass, root biomass, total root length, and the root length of fine roots in the soil layer at both water availabilities, but increased net photosynthetic rate (Pn) and retained stable water use efficiency (WUE) at low water availability. However, there were no significant differences between the soil-filled fissure group and soil group in the biomass accumulation and allocation as well as Pn. Nevertheless, the SF group decreased the root distribution in total and in the soil layer, and also increased WUE at low water availability. Across all treatments, fissure size had no effect on plant growth or photosynthesis. Karst fissures filled with soil can alleviate drought impacts on plant root growth, which involves adjusting root distribution strategies and increasing water use efficiency. These results suggest that rock fissures can be involved in long-term plant responses to drought stress and vegetation restoration in rocky mountain environments under global climate change.

Simultaneous quantitation of 15 bioactive components in Yupingfeng granules by LC-MS/MS.

Yupingfeng granules (YPFG) is commonly used in the treatment of immunological diseases, inflammations, and pulmonary diseases. Several studies have found that chromones, flavones, and saponins were the major bioactive compounds of YPFG. However, few studies have reported accurate quantification methods of these compounds. This study aimed to establish a simple and rapid method by using liquid chromatography-tandem mass spectrometry (LC-MS/MS) to determine 15 bioactive compounds in YPFG. The experimental parameters including extraction methods, extraction solvents, extraction time, solid-liquid ratio, and LC-MS/MS condition were optimized. The linearity, precision, repeatability, stability, and recovery of the established method were evaluated. The contents of 15 bioactive compounds in seven batches of YPFG samples were analyzed by the established method and the results were compared with the values determined by HPLC. The optimal extraction condition was to extract 0.1 g of YPFG by ultrasound with 50 mL 50% ethanol for 30 min. A Waters ACQUITY UPLCBEH C18 column using the 0.1% formic acid water solution and acetonitrile as mobile phase with a gradient elution was applied to the chromatographic separation. The linearity, precision, repeatability, stability, and recovery of the method were within acceptable ranges. Compared with HPLC analysis methods in Chinese Pharmacopoeia and literature, the established method was faster, simpler, more accurate, and more reliable. The method of simultaneous determination of 15 components in YPFG by LC-MS might provide a basis for the study of the bioactive compounds and the improvement of the quality standard of YPFG.

Efficient learning of mixed-state tomography for photonic quantum walk.

Noise-enhanced applications in open quantum walk (QW) has recently seen a surge due to their ability to improve performance. However, verifying the success of open QW is challenging, as mixed-state tomography is a resource-intensive process, and implementing all required measurements is almost impossible due to various physical constraints. To address this challenge, we present a neural-network-based method for reconstructing mixed states with a high fidelity (∼97.5%) while costing only 50% of the number of measurements typically required for open discrete-time QW in one dimension. Our method uses a neural density operator that models the system and environment, followed by a generalized natural gradient descent procedure that significantly speeds up the training process. Moreover, we introduce a compact interferometric measurement device, improving the scalability of our photonic QW setup that enables experimental learning of mixed states. Our results demonstrate that highly expressive neural networks can serve as powerful alternatives to traditional state tomography.

Interferon-γ in the tumor microenvironment promotes the expression of B7H4 in colorectal cancer cells, thereby inhibiting cytotoxic T cells.

The bioactivity of interferon-γ (IFN-γ) in cancer cells in the tumor microenvironment (TME) is not well understood in the current immunotherapy era. We found that IFN-γ has an immunosuppressive effect on colorectal cancer (CRC) cells. The tumor volume in immunocompetent mice was significantly increased after subcutaneous implantation of murine CRC cells followed by IFN-γ stimulation, and RNA sequencing showed high expression of B7 homologous protein 4 (B7H4) in these tumors. B7H4 promotes CRC cell growth by inhibiting the release of granzyme B (GzmB) from CD8+ T cells and accelerating apoptosis in CD8+ T cells. Furthermore, interferon regulatory factor 1 (IRF1), which binds to the B7H4 promoter, is positively associated with IFN-γ stimulation-induced expression of B7H4. The clinical outcome of patients with CRC was negatively related to the high expression of B7H4 in cancer cells or low expression of CD8 in the microenvironment. Therefore, B7H4 is a biomarker of poor prognosis in CRC patients, and interference with the IFN-γ/IRF1/B7H4 axis might be a novel immunotherapeutic method to restore the cytotoxic killing of CRC cells.

A von-Neumann-like photonic processor and its application in studying quantum signature of chaos.

Photonic quantum computation plays an important role and offers unique advantages. Two decades after the milestone work of Knill-Laflamme-Milburn, various architectures of photonic processors have been proposed, and quantum advantage over classical computers has also been demonstrated. It is now the opportune time to apply this technology to real-world applications. However, at current technology level, this aim is restricted by either programmability in bulk optics or loss in integrated optics for the existing architectures of processors, for which the resource cost is also a problem. Here we present a von-Neumann-like architecture based on temporal-mode encoding and looped structure on table, which is capable of multimode-universal programmability, resource-efficiency, phase-stability and software-scalability. In order to illustrate these merits, we execute two different programs with varying resource requirements on the same processor, to investigate quantum signature of chaos from two aspects: the signature behaviors exhibited in phase space (13 modes), and the Fermi golden rule which has not been experimentally studied in quantitative way before (26 modes). The maximal program contains an optical interferometer network with 1694 freely-adjustable phases. Considering current state-of-the-art, our architecture stands as the most promising candidate for real-world applications.

Evaluation of the lncRNA-miRNA-mRNA ceRNA network in lungs of miR-147 -/- mice.

Background: Previous studies have documented important roles for microRNA-147 (miR-147) in inflammation, radiation-induced injury, cancer, and a range of other diseases. Murine lungs exhibit high levels of miRNA, mRNA, and lncRNA expression. However, very little research to date has focused on the lncRNA-miRNA-mRNA competing endogenous RNA (ceRNA) networks associated with miR-147, and the regulation of lncRNAs and miRNAs in this setting remains poorly understood. Methods: After establishing a miR-147-/- model mouse, samples of lung tissue were harvested for RNA-sequencing, and differentially expressed lncRNAs, miRNAs, and mRNAs were identified. The miRNA targets of these lncRNAs and the identified miRNAs were first overlapped to facilitate the prediction of target mRNAs, with analyses then examining the overlap between these targets and mRNAs that were differentially expressed. Then, these target mRNAs were subjected to pathway enrichment analyses. These results were ultimately used to establish a miR-147-related ceRNA network. Results: Relative to wild-type mice, the lungs of miR-147-/- mice exhibited 91, 43, and 71 significantly upregulated lncRNAs, miRNAs, and mRNAs, respectively, together with 114, 31, and 156 that were significantly downregulated. The lncRNA-miRNA-mRNA network established based on these results led to the identification of Kcnh6 as a differentially expressed hub gene candidate and enabled the identification of a range of regulatory relationships. KEGG pathway enrichment showed that the mRNA targets of differentially expressed lncRNAs and miRNAs in the mice were associated with tumor-related signaling, endometrial cancer, bladder cancer, and ErbB signaling. Conclusion: These results suggest that the identified ceRNA network in miR-147-/- mice shapes tumor-associated signaling activity, with miR-147 potentially regulating various lncRNAs and miRNAs through Kcnh6, ultimately influencing tumorigenesis. Future studies of the lncRNA, miRNA, and mRNA regulatory targets shown to be associated with miR-147 in the present study may ultimately lead to the identification of novel clinically relevant targets through which miR-147 shapes the pathogenesis of cancer and other diseases.

Synthesis of polyvinylethylene glycols (PVEGs) via polyetherification of vinylethylene carbonate by synergistic catalysis.

An efficient and controllable polyetherification of vinylethylene carbonate (VEC) using diols as initiators is developed. By using a synergistic catalysis with palladium and boron reagents under mild conditions, the polymerization process enables the regioselective production of a series of polyvinylethylene glycols (PVEGs) bearing pendent vinyl groups in high yields with accurate molecular weight control and narrow molecular weight distribution. The utility of PVEGs is demonstrated by the production of functional polyurethanes and post-polymerization modification via thiol-ene photo-click chemistry.

The prognostic value of collateral circulation in coronary chronic total occlusion underwent percutaneous coronary intervention.

BACKGROUND: The prognostic value of coronary collateral circulation (CC) in patients undergoing chronic total occlusion (CTO) percutaneous coronary intervention (PCI) is underdetermined. The purpose of the study was to assess the prognostic value of current two CC grading systems and their association with long-term outcomes in patients with CTO underwent PCI. METHODS: We consecutively enrolled patients with single-vessel CTO underwent PCI between January 2010 and December 2013. All patients were categorized into well-developed or poor-developed collaterals group according to angiographic Werner's CC (grade 2 vs. grade 0-1) or Rentrop (grade 3 vs. grade 0-2) grading system. The primary endpoint was 5-year cardiac death. RESULTS: Of 2452 enrolled patients, the overall technical success rate was 74.1%. Well-developed collaterals were present in 686 patients (28.0%) defined by Werner's CC grade 2, and in 1145 patients (46.7%) by Rentrop grade 3. According to Werner's CC grading system, patients with well-developed collaterals had a lower rate of 5-year cardiac death compared with those with poor-developed collaterals (1.6% vs. 3.3%, P = 0.02), those with suboptimal recanalization was associated with higher rate of 5-year cardiac death compared with optimal recanalization (4.7% vs. 0.8%, P = 0.01) and failure patients (4.7% vs. 1.6%, P = 0.12). However, the similar effect was not shown in Rentrop grading system. CONCLUSIONS: In patients with the single-vessel CTO underwent PCI, well-developed collaterals by Werner's CC definition were associated with lower rate of 5-year cardiac death. Werner's CC grading system had a greater prognostic value than Rentrop grading system in patients with CTO underwent PCI.

Diagnostic performance of intravascular ultrasound-based fractional flow reserve in evaluating of intermediate left main stenosis.

BACKGROUND: The recently introduced ultrasonic flow ratio (UFR), is a novel fast computational method to derive fractional flow reserve (FFR) from intravascular ultrasound (IVUS) images. In the present study, we evaluate the diagnostic performance of UFR in patients with intermediate left main (LM) stenosis. METHODS: This is a prospective, single center study enrolling consecutive patients with presence of intermediated LM lesions (diameter stenosis of 30%-80% by visual estimation) underwent IVUS and FFR measurement. An independent core laboratory assessed offline UFR and IVUS-derived minimal lumen area (MLA) in a blinded fashion. RESULTS: Both UFR and FFR were successfully achieved in 41 LM patients (mean age, 62.0 ± 9.9 years, 46.3% diabetes). An acceptable correlation between UFR and FFR was identified (r = 0.688, P < 0.0001), with an absolute numerical difference of 0.03 (standard difference: 0.01). The area under the curve (AUC) in diagnosis of physiologically significant coronary stenosis for UFR was 0.94 (95% CI: 0.87-1.01), which was significantly higher than angiographic identified stenosis > 50% (AUC = 0.66, P < 0.001) and numerically higher than IVUS-derived MLA (AUC = 0.82; P = 0.09). Patient level diagnostic accuracy, sensitivity and specificity for UFR to identify FFR ≤ 0.80 was 82.9% (95% CI: 70.2-95.7), 93.1% (95% CI: 82.2-100.0), 58.3% (95% CI: 26.3-90.4), respectively. CONCLUSION: In patients with intermediate LM diseases, UFR was proved to be associated with acceptable correlation and high accuracy with pressure wire-based FFR as standard reference. The present study supports the use of UFR for functional evaluation of intermediate LM stenosis.

Experimental recognition of vortex beams in oceanic turbulence combining the Gerchberg-Saxton algorithm and convolutional neural network.

In underwater wireless optical communication (UWOC), vortex beams carrying orbital angular momentum (OAM) can improve channel capacity but are vulnerable to oceanic turbulence (OT), leading to recognition errors. To mitigate this issue, we propose what we believe to be a novel method that combines the Gerchberg-Saxton (GS) algorithm-based recovery with convolutional neural network (CNN)-based recognition (GS-CNN). Our experimental results demonstrate that superposed Laguerre-Gaussian (LG) beams with small topological charge are ideal information carriers, and the GS-CNN remains effective even when OT strength C n2 is high up to 10-11 K 2 m -2/3. Furthermore, we use 16 kinds of LG beams to transmit a 256-grayscale digital image, giving rise to an increase in recognition accuracy from 0.75 to 0.93 and a decrease in bit error ratio from 3.98×10-2 to 6.52×10-3 compared to using the CNN alone.

An increase in SNHG5 expression is associated with poor cancer prognosis, according to a meta-analysis.

BACKGROUND: He long noncoding RNA small nucleolar host RNA 5 (SNHG5) is highly expressed in many cancers, and there is a notable correlation between the elevated expression of SNHG5 and survival outcome in cancer patients. The objective of this study was to conduct a meta-analysis to evaluate the correlation between SNHG5 expression and the clinical outcome of cancer patients. METHODS: Six relevant electronic databases were exhaustively searched, and, depending on the inclusion and exclusion criteria, appropriate literature was obtained. The Newcastle-Ottawa Scale (NOS) score was utilized to evaluate the quality of the research for every article included, and pertinent data from each study were carefully extracted. Hazard ratios (HRs), odds ratios (ORs) and 95% confidence intervals (CIs) were combined to explore the association of SNHG5 expression levels with cancer prognosis, and sensitivity analyses and assessments of publication bias were also conducted to investigate any possibility in the publication of the studies. RESULTS: Eleven studies encompassing 721 patients were ultimately collected. When combined, the hazard ratios (HRs) revealed a substantial direct correlation between elevated SNHG5 expression and an unfavourable prognosis for cancer patients (HR = 1.90, 95% CI 0.87-4.15); however, the correlation did not reach statistical significance. Furthermore, high SNHG5 expression was predictive of advanced TNM stage (OR: 1.988, 95% CI 1.205-3.278) and larger tumour size (OR: 1.571, 95% CI 1.090-2.264); moreover, there were nonsignificant relationships between SNHG5 expression and DM (OR: 0.449, 95% CI 0.077-2.630), lymph node metastasis (OR: 1.443, 95% CI 0.709-2.939), histological grade (OR: 2.098, 95% CI 0.910-4.838), depth of invasion (OR: 1.106, 95% CI 0.376-3.248), age (OR: 0.946, 95% CI 0.718-1.247) and sex (OR: 0.762, 95% CI 0.521-1.115). CONCLUSION: SNHG5 expression is typically increased in the majority of tumour tissues. Elevated SNHG5 expression may indicate poor prognosis in cancer patients. Therefore, SNHG5 is a promising potential therapeutic target for tumours and a reliable prognostic biomarker.

Protective effects of Prussian blue nanozyme against sepsis-induced acute lung injury by activating HO-1.

Sepsis is a life-threatening condition involving dysfunctional organ responses stemming from dysregulated host immune reactions to various infections. The lungs are most prone to failure during sepsis, resulting in acute lung injury (ALI). ALI is associated with oxidative stress and inflammation, and current therapeutic strategies are limited. To develop a more specific treatment, this study aimed to synthesise Prussian blue nanozyme (PBzyme), which can reduce oxidative stress and inflammation, to alleviate ALI. PBzyme with good biosafety was synthesised using a modified hydrothermal method. PBzyme was revealed to be an activator of haem oxygenase-1 (HO-1), improving survival rate and ameliorating lung injury in mice. Zinc protoporphyrin, an inhibitor of HO-1, inhibited the prophylactic therapeutic efficacy of PBzyme on ALI, and affected the nuclear factor-κB signaling pathway and activity of HO-1. This study demonstrates that PBzyme can alleviate oxidative stress and inflammation through HO-1 and has a prophylactic therapeutic effect on ALI. This provides a new strategy and direction for the clinical treatment of sepsis-induced ALI.

Screening of Sugarcane Proteins Associated with Defense against Leifsonia xyli subsp. xyli, Agent of Ratoon Stunting Disease.

Sugarcane is the most important sugar crop and one of the leading energy-producing crops in the world. Ratoon stunting disease (RSD), caused by the bacterium Leifsonia xyli subsp. xyli, poses a huge threat to ratoon crops, causing a significant yield loss in sugarcane. Breeding resistant varieties is considered the most effective and fundamental approach to control RSD in sugarcane. The exploration of resistance genes forms the foundation for breeding resistant varieties through molecular technology. The pglA gene is a pathogenicity gene in L. xyli subsp. xyli, encoding an endopolygalacturonase. In this study, the pglA gene from L. xyli subsp. xyli and related microorganisms was analyzed. Then, a non-toxic, non-autoactivating pglA bait was successfully expressed in yeast cells. Simultaneously the yeast two-hybrid library was generated using RNA from the L. xyli subsp. xyli-infected sugarcane. Screening the library with the pglA bait uncovered proteins that interacted with pglA, primarily associated with ABA pathways and the plant immune system, suggesting that sugarcane employs these pathways to respond to L. xyli subsp. xyli, triggering pathogenicity or resistance. The expression of genes encoding these proteins was also investigated in L. xyli subsp. xyli-infected sugarcane, suggesting multiple layers of regulatory mechanisms in the interaction between sugarcane and L. xyli subsp. xyli. This work promotes the understanding of plant-pathogen interaction and provides target proteins/genes for molecular breeding to improve sugarcane resistance to L. xyli subsp. xyli.

Diagnostic performance of ultrasonic flow ratio versus quantitative flow ratio for assessment of coronary stenosis.

BACKGROUND: Ultrasonic flow ratio (UFR) is a novel intravascular ultrasound (IVUS)-derived modality for fast computation of fractional flow reserve (FFR) without pressure wires and adenosine. AIMS: This study was sought to compare the diagnostic performance of UFR and quantitative flow ratio (QFR), using FFR as the reference standard. METHODS: This is a retrospective study enrolling consecutive patients with intermediate coronary artery lesions (diameter stenosis of 30%-90% by visual estimation) for IVUS and FFR measurement. UFR and QFR were performed offline in a core-lab by independent analysts blinded to FFR. RESULTS: From December 2022 to May 2023, a total of 78 eligible patients were enrolled. IVUS and FFR measurements were successfully conducted in 104 vessels, finally 98 vessels with both FFR, UFR and QFR evaluation were analyzed. Mean FFR was 0.79 ± 0.12. UFR showed a strong correlation with FFR similar to QFR (r = 0.83 vs. 0.82, p = 0.795). Diagnostic accuracy of UFR was non-inferior to QFR (94% [89%-97%] versus 90% [84%-94%], p = 0.113). Sensitivity and specificity in identifying hemodynamically significant stenosis were comparable between UFR and QFR (sensitivity: 89% [79%-96%] versus 85% [74%-92%], p = 0.453; specificity: 97% [91%-99%] versus 95% [88%-99%], p = 0.625). The area under curve for UFR was 0.95 [0.90-0.98], non-inferior to QFR (difference = 0.021, p = 0.293), and significantly higher than minimum lumen area (MLA; difference = 0.13, p < 0.001). Diagnostic accuracy of UFR and QFR was not statically different in bifurcation nor non-bifurcation lesions. CONCLUSIONS: UFR showed excellent concordance with FFR, non-inferior to QFR, superior to MLA. UFR provides a potentiality for the integration of physiological assessment and intravascular imaging in clinical practice.

Evaluation of extravascular lung water and cardiac function in normal vaginal delivery by intrapartum bedside ultrasound.

BACKGROUND: Healthy parturients may experience pulmonary edema and disturbed cardiac function during labor. We aimed to evaluate the extravascular lung water (EVLW), intravascular volume, and cardiac function of normal parturients during spontaneous vaginal delivery by bedside ultrasound. And to explore the correlation between EVLW and intravascular volume, cardiac function. METHODS: This was a prospective observational study including 30 singleton-term pregnant women undergoing spontaneous vaginal delivery. Bedside ultrasound was performed at the early labor, the end of the second stage of labor, 2 and 24 h postpartum, and 120 scanning results were recorded. EVLW was evaluated by the echo comet score (ECS) obtained by the 28-rib interspaces technique. Inferior vena cava collapsibility index (IVC-CI), left ventricle ejection fraction, right ventricle fractional area change, left and right ventricular E/A ratio, and left and right ventricular index of myocardial performance (LIMP and RIMP) were measured. Measurements among different time points were compared, and the correlations between ECS and other measurements were analyzed. RESULTS: During the spontaneous vaginal delivery of healthy pregnant women, 2 had a mild EVLW increase at the early labor, 8 at the end of the second stage of labor, 13 at 2 h postpartum, and 4 at 24 h postpartum (P < 0.001). From the early labor to 24 h postpartum, ECS first increased and then decreased, reaching its peak at 2 h postpartum (P < 0.001). IVC-CI first decreased and then increased, reaching its minimum at the end of the second stage of labor (P < 0.001). RIMP exceeded the cut-off value of 0.43 at the end of the second stage of labor. ECS was weakly correlated with IVC-CI (r=-0.373, P < 0.001), LIMP (r = 0.298, P = 0.022) and RIMP (r = 0.211, P = 0.021). CONCLUSIONS: During spontaneous vaginal delivery, the most vital period of perinatal care is between the end of the second stage of labor and 2 h postpartum, because the risk of pulmonary edema is higher and the right ventricle function may decline. IVC-CI can be used to evaluate maternal intravascular volume. The increase in EVLW may be related to the increase in intravascular volume and the decrease in ventricular function.

MHESMMR: a multilevel model for predicting the regulation of miRNAs expression by small molecules.

According to the expression of miRNA in pathological processes, miRNAs can be divided into oncogenes or tumor suppressors. Prediction of the regulation relations between miRNAs and small molecules (SMs) becomes a vital goal for miRNA-target therapy. But traditional biological approaches are laborious and expensive. Thus, there is an urgent need to develop a computational model. In this study, we proposed a computational model to predict whether the regulatory relationship between miRNAs and SMs is up-regulated or down-regulated. Specifically, we first use the Large-scale Information Network Embedding (LINE) algorithm to construct the node features from the self-similarity networks, then use the General Attributed Multiplex Heterogeneous Network Embedding (GATNE) algorithm to extract the topological information from the attribute network, and finally utilize the Light Gradient Boosting Machine (LightGBM) algorithm to predict the regulatory relationship between miRNAs and SMs. In the fivefold cross-validation experiment, the average accuracies of the proposed model on the SM2miR dataset reached 79.59% and 80.37% for up-regulation pairs and down-regulation pairs, respectively. In addition, we compared our model with another published model. Moreover, in the case study for 5-FU, 7 of 10 candidate miRNAs are confirmed by related literature. Therefore, we believe that our model can promote the research of miRNA-targeted therapy.

Soil nutrient limitation and natural enemies promote the establishment of alien species in native communities.

The invasion of alien plant species threatens the composition and diversity of native communities. However, the invasiveness of alien plants and the resilience of native communities are dependent on the interactions between biotic and abiotic factors, such as natural enemies and nutrient availability. In our study, we simulated the invasion of nine invasive plant species into native plant communities using two levels of nutrient availability and suppression of natural enemies. We evaluated the effect of biotic and abiotic factors on the response of alien target species and the resistance of native communities to invasion. The results showed that the presence of enemies (enemy release) increased the biomass proportion of alien plants while decreasing that of native communities in the absence of nutrient addition. Furthermore, we also found that the negative effect of enemy suppression on the evenness of the native community and the root-to-shoot ratio of alien target species was greatest under nutrient addition. Therefore, nutrient-poor and natural enemies might promote the invasive success of alien species in native communities, whereas nutrient addition and enemy suppression can better enhance the resistance of native plant communities to invasion.

Synthesis and antibacterial activity evaluation of octapeptin derivatives / 药学学报

Octapeptin has strong antibacterial activity against Gram-negative bacteria such as Escherichia coli, Klebsiella pneumoniae and Acinetobacter baumannii, while it also has activity against some Gram-positive bacteria. This study used natural octapeptin A3 and B3 as lead compounds for structural modification. Twenty-one peptide derivatives (including A3 and B3) containing eight amino acid residues were prepared by solid-phase synthesis, and evaluated for antibacterial activity and renal cytotoxicity. Among them, three compounds 6, 7 and 17 exhibited broad-spectrum antibacterial activity and significantly enhanced the activity for Gram-positive bacteria while maintaining the activity of Gram-negative bacteria. Several compounds improved the activity for Pseudomonas aeruginosa. Compound 7 was active against all test strains and had relatively low renal cytotoxicity. The results provide a basis for the further development of novel polypeptide antibiotics.