Impact of Airborne Pathogen-Derived Extracellular Vesicles on Macrophages Revealed by Raman Spectroscopy and Multiomics.

Long-term exposure to the indoor environment may pose threats to human health due to the presence of pathogenic bacteria and their byproducts. Nanoscale extracellular vesicles (EVs) extensively secreted from pathogenic bacteria can traverse biological barriers and affect physio-pathological processes. However, the potential health impact of EVs from indoor dust and the underlying mechanisms remain largely unexplored. Here, Raman spectroscopy combined with multiomics (genomics and proteomics) was used to address these issues. Genomic analysis revealed that Pseudomonas was an efficient producer of EVs that harbored 68 types of virulence factor-encoding genes. Upon exposing macrophages to environmentally relevant doses of Pseudomonas aeruginosa PAO1-derived EVs, macrophage internalization was observed, and release of inflammatory factors was determined by RT-PCR. Subsequent Raman spectroscopy and unsupervised surprisal analysis of EV-affected macrophages distinguished metabolic alterations, particularly in proteins and lipids. Proteomic analysis further revealed differential expression of proteins in inflammatory and metabolism-related pathways, indicating that EV exposure induced macrophage metabolic reprogramming and inflammation. Collectively, our findings revealed that pathogen-derived EVs in the indoor environments can act as a new mediator for pathogens to exert adverse health effects. Our method of Raman integrated with multiomics offers a complementary approach for rapid and in-depth understanding of EVs' impact.

First report of sweet corn root rot caused by Pythium graminicola in southeast China.

Sweet corn (Zea mays L.) is widely consumed as fresh or frozen vegetable worldwide, and Zhengtian68 is a popular commercial variety cultivated extensively in southeast China. In May 2021, 40% of the inbred line YK063 (the female parent of Zhengtian68) showed early yellowing of the leaves at flowering time in a commercial seed production field with a total area of 0.5 ha in Guangzhou, Guangdong Province after a heavy rain. Black and rotten roots were observed in the diseased plants after digging the whole plant out of the soil. Grain filling was also severely affected, adversely impacting seed production. Diseased plants were more easily found in the lower section of the field, where water accumulated after rainfall. Three plants with rotten roots were collected randomly from the field to identify the causal pathogen. The diseased roots were cut into 2-3 mm sections, washed in 75% ethanol for 2 minutes and rinsed three times in sterile distilled water. Four to five sections per plant were placed on potato dextrose agar (PDA) and incubated at 28℃ in the dark for three days. Three isolates GF1, GF2, and GF3 from different plants were purified by hyphal tip isolation and transferred to new PDA and 10% V8 juice agar (16 g agar, 3 g CaCO3, 100 ml V8 juice, and 900 ml distilled water) and incubated at 28℃ for 10 days in darkness for further investigation. Translucent, glassy mycelial growth was observed on the PDA media. Morphological characteristics of the 3 isolates were observed under a microscope from the 10%V8 media. The hyphae were aseptate and 2.7 to 4.5 µm wide (mean±SD,3.3±0.44µm, n=44). Sporangia were inflated, or lobulate, terminal, or intercalary. Oogonia were globose, smooth-walled, terminal, or occasionally intercalary, with a diameter of 17.2-24.1 µm (mean±SD, 21.3±2.14µm, n=29). Oospores were globose, plerotic, smooth, and 14.5-21.2 µm (mean±SD, 18.7±2.07µm, n=35) in diameter. The antheridia were diclinous or monoclinous, not intercalary, and one to six antheridia were attached to each oogonium. Based on these morphological characteristics, 3 isolates were identified as Pythium spp. including Pythium graminicola (Van der Plaats-Niterink 1981). Genomic DNA was extracted from the mycelia grown on PDA using a Fungal Genomic DNA kit (Scintol, Beijing, China) according to the manufacturer's instructions. The cytochrome oxidase II (Cox II) gene and internal transcribed spacer (ITS) region of the rDNA were amplified using the primers FM58/FM66 (Martin 2000) and ITS4/ITS5 (White et al. 1990) respectively. Amplification was performed in a 50µl reaction volume using 25 µl PCR Mix (Trans Gene, Beijing, China), 3 µl genomic DNA (50 ng/µl), 1 µl each forward and reverse primer (10 µM), and 20 µl ddH2O. The PCR program was as follows: initial denaturation at 95°C for 30 s, 35 cycles of denaturation at 95°C for 30 s, annealing at 60°C for 60 s, extension at 72°C for 60 s, and a final extension at 72°C for 10 min. PCR products were sequenced and submitted to GenBank (accession no. OQ504322, OQ933130, and OQ933212 for ITS; OQ512002, OQ942203, and OQ942204 for Cox II). BLASTn analysis revealed that the ITS and Cox II sequences showed more than 98.62% similarity (721/724bp, 722/724bp,723/724bp for ITS; 514/514bp, 506/507bp, 500/507bp for Cox II) to P. graminicola ATCC96234 (accession no. AB095045 for ITS, and AB160849 for Cox II), respectively, supporting the morphological analysis. A neighbor-joining phylogenetic analysis of the ITS and Cox II concatenated sequence further confirmed that the isolates were P. graminicola. To test the pathogenicity of GF1, GF2, and GF3 a wheat seed inoculum was prepared as previously described (Qu et al. 2016). Sweet corn YK063 plants were planted in sterilized nutrient soil in plastic pots (one plant per pot) and grown in a greenhouse at 28℃ with 60% humidity and a 12-h/12-h light-dark cycle. For each isolate,10 plants were inoculated with 20 infected wheat seeds around the roots at the V5 stage, while 10 other YK063 plants were inoculated with the non-infected wheat seeds as a control. The experiment was repeated once. Three weeks later, the non-inoculated plants were asymptomatic. In contrast, inoculated plants showed stunning, yellowing of the leaves, root rot, and decreased production of lateral roots, exhibiting symptoms similar to those originally described for the disease. P. graminicola was successfully reisolated from the diseased roots and identified by morphological characteristics and sequencing of the ITS and Cox II as the causal agent for this root rot disease, fulfilling Koch's postulate for defining a causal agent. P. graminicola was reported as a causal agent of damping-off on dent corn in Georgia (Li et al. 2018). To our knowledge, this is the first report of P. graminicola causing root rot in sweet corn in southeast China. Identification of this pathogen will facilitate further research on this disease and the development of effective strategies to control the disease.

Canagliflozin Inhibited the Activity of Hemolysin and Reduced the Inflammatory Response Caused by Streptococcus suis.

Highly virulent Streptococcus suis (S. suis) infections can cause Streptococcal toxic shock-like syndrome (STSLS) in pigs and humans, in which an excessive inflammatory response causes severe damage. Hemolysin (SLY) is a major virulence factor of S. suis serotype 2 that produces pores in the target cell membrane, leading to cytoplasmic K+ efflux and activation of the NLRP3 inflammasome, ultimately causing STSLS. The critical aspect of hemolysin in the pathogenesis of S. suis type 2 makes it an attractive target for the development of innovative anti-virulence drugs. Here, we use the S. suis toxin protein (SLY) as a target for virtual screening. A compound called canagliflozin, a hypoglycemic agent, was identified through screening. Canagliflozin significantly inhibits the hemolytic activity of hemolysin. The results combined with molecular dynamics simulation, surface plasmon resonance, and nano differential scanning fluorimetry show that canagliflozin inhibits the hemolytic activity of SLY by binding to SLY. In addition, canagliflozin markedly reduced the release of SC19-induced inflammatory factors at the cellular level and in mice. Importantly, the combination of canagliflozin and ampicillin had a 90% success rate in mice, significantly greater than the therapeutic effect of ampicillin. The findings suggest that canagliflozin may be a promising new drug candidate for S. suis infections.

First report of bacterial leaf streak in sweet corn caused by Pantoea ananatis in southeast China.

Sweet corn (Zea mays convar. saccharata var. rugosa) is a popular vegetable crop in southeast China. During the spring seasons of 2018-2021, a serious outbreak of bacterial leaf streak was observed in sweet corn variety Yuetian28 in the field in Guangzhou, Guangdong Province. The disease incidence was 50%-70%. Infected leaves initially displayed long, chlorotic streaks parallel to veins at the V5-V6 stage, and then turned white or brown and dried out over the course of disease development. In severe infections, leaf lesion coalesced to form large irregular blight areas (Fig. S1A). To investigate this disease, we collected 0.5 cm2 samples of infected leaves from four plants after surface sterilization and rinsed them three times with sterile distilled water. We placed all leaf samples on nutrient agar (NA) medium and incubated them at 28℃ for 48 hours. Bright-yellowish colonies were observed near the edges of the samples. We picked the colonies and re-streaked them onto NA medium three times to obtain pure cultures. Four isolates, GZ2201, GZ2202, GZ2203, and GZ2204, were selected for further study. All isolates were gram-negative rods and were negative for oxidase, urease, nitrate reductase reactions, and gelatin liquefaction. They were positive for catalase, citrate utilization, indole production, and the Voges-Proskauer test. We sequenced the 16S rDNA, rpoB, leuS, and gyrB sequences using previously reported primers (Brady et al. 2008) and deposited the sequences in GenBank (accession nos. ON740665 to ON740668 for 16S rDNA; ON755167 to ON755170 for rpoB; ON755171 to ON755174 for leuS; and OP227136 to OP227139 for gyrB). The sequences share >98% identity with sequences from Pantoea ananatis type strain LMG2665 (GenBank JFZU01) indicating that the causal pathogen of bacteria leaf streak of sweet corn is P. ananatis (Fig. S1B). Phylogenetic analysis of gyrB, leuS, and rpoB concatenated sequence showed that the four isolates clustered with P. ananatis (Fig S2). To test the pathogenicity of the isolates of P. ananatis on the sweet corn variety Yuetian28, we inoculated plants at the V3 stage by syringe infiltration of bacterial suspension (108 CFU/ml) (Kini et al. 2020) or sterile distilled water as a negative control. Inoculated plants were placed in a growth chamber at 28 ℃, 60% relative humidity, 16-h/8-h light-dark cycle. After 7 days of incubation, chlorotic streaks resembling the original symptoms developed on inoculated plants (Fig. S1D), while control plants remained symptomless (Fig. S1C). We successfully re-isolated bacteria from the inoculated plants and confirmed their identity by sequencing of 16S rDNA, rpoB, leuS, and gyrB. P. ananatis was previously reported to cause leaf spot disease in maize grown in Argentina, Ecuador, and China (Alippi et al. 2010; Toaza et al. 2021; Cui et al. 2022). To our knowledge, this is the first report of P. ananatis causing leaf streak in sweet corn in southeast China. Further research on P. ananatis management is needed to help control disease spread.

miR-495 Regulates Cellular Reactive Oxygen Species Levels by Targeting sod2 To Inhibit Intracellular Survival of Mycobacterium tuberculosis in Macrophages.

Mycobacterium tuberculosis is a chronic infectious disease pathogen. To date, tuberculosis is a major infectious disease that endangers human health. To better prevent and treat tuberculosis, it is important to study the pathogenesis of M. tuberculosis. Based on early-stage laboratory research results, in this study, we verified the upregulation of sod2 in Bacillus Calmette-Guérin (BCG) and H37Rv infection. By detecting BCG/H37Rv intracellular survival in sod2-silenced and sod2-overexpressing macrophages, sod2 was found to promote the intracellular survival of BCG/H37Rv. miR-495 then was determined to be downregulated by BCG/H37Rv. BCG/H37Rv can upregulate sod2 expression by miR-495 to promote the intracellular survival of BCG/H37Rv through a decline in ROS levels. This study provides a theoretical basis for developing new drug targets and treating tuberculosis.

General characteristics of the influence of surfactants on the bacteriolytic activity of lysozyme based on the example of enzymatic lysis of Lactobacillus plantarum cells in the presence of Tween 21 and SDS.

The general characteristics of the effect of surfactants on the activity of lysozyme were demonstrated. The kinetics of bacterial cell lysis is consistent with the Michaelis-Menten equation and the presence of surfactants does not shift the pH-optimum of activity. Surfactants do not change the Km value but instead, affect the Vmax value. The experimental dependencies are well described by theoretical equations, which assume three surfactant binding sites on the lysozyme molecule. The dependencies of the activity of lysozyme on the surfactant concentration are either a step type (i.e., a higher plateau becomes a lower plateau), or a dependency with a maximum and continuation of the curve in the form of a plateau but with an increase in the surfactant concentration. It can be assumed that there is a mechanism for the regulation of lysozyme activity by an unknown natural factor that has a suitable hydrophobic radical capable of binding to the surface of lysozyme.

Effective Antibacterial and Antihemolysin Activities of Ellipticine Hydrochloride against Streptococcus suis in a Mouse Model.

Streptococcal toxic shock-like syndrome (STSLS) caused by the epidemic strain of Streptococcus suis leads to severe inflammation and high mortality. The life and health of humans and animals are also threatened by the increasingly severe antimicrobial resistance in Streptococcus suis There is an urgent need to discover novel strategies for the treatment of S. suis infection. Suilysin (SLY) is considered to be an important virulence factor in the pathogenesis of S. suis In this study, ellipticine hydrochloride (EH) was reported as a compound that antagonizes the hemolytic activity of SLY. In vitro, EH was found to effectively inhibit SLY-mediated hemolytic activity. Furthermore, EH had a strong affinity for SLY, thereby directly binding to SLY to interfere with the hemolytic activity. Meanwhile, it was worth noting that EH was also found to have a significant antibacterial activity. In vivo, compared with traditional ampicillin, EH not only significantly improved the survival rate of mice infected with S. suis 2 strain Sc19 but also relieved lung pathological damage. Furthermore, EH effectively decreased the levels of inflammatory cytokines (interleukin-6 [IL-6], tumor necrosis factor alpha [TNF-α]) and blood biochemistry enzymes (alanine transaminase [ALT], aspartate transaminase [AST], creatine kinase [CK]) in Sc19-infected mice. Additionally, EH markedly reduced the bacterial load of tissues in Sc19-infected mice. In conclusion, our findings suggest that EH can be a potential compound for treating S. suis infection in view of its antibacterial and antihemolysin activity.IMPORTANCE In recent years, the inappropriate use of antibiotics has unnecessarily caused the continuous emergence of resistant bacteria. The antimicrobial resistance of Streptococcus suis has also become an increasingly serious problem. Targeting virulence can reduce the selective pressure of bacteria on antibiotics, thereby alleviating the development of bacterial resistance to a certain extent. Meanwhile, the excessive inflammatory response caused by S. suis infection is considered the primary cause of acute death. Here, we found that ellipticine hydrochloride (EH) exhibited effective antibacterial and antihemolysin activities against S. suisin vitroIn vivo, compared with ampicillin, EH had a significant protective effect on S. suis serotype 2 strain Sc19-infected mice. Our results indicated that EH, with dual antibacterial and antivirulence effects, will contribute to treating S. suis infections and alleviating the antimicrobial resistance of S. suis to a certain extent. More importantly, EH may develop into a promising drug for the prevention of acute death caused by excessive inflammation.

Risk and clinical outcomes of COVID-19 in patients with rheumatic diseases compared with the general population: a systematic review and meta-analysis.

Patients with rheumatic diseases are often more susceptible to different bacteria and viruses because of immune impairment, but it is not clear whether there is a higher risk of infection and a more serious course of disease for novel coronavirus (SARS-CoV-2). We performed this systematic review and meta analysis to assess the risk and clinical outcomes of COVID-19 in patients with rheumatic diseases compared with the general population. We searched PubMed, EMBASE, Scopus and Web of Science databases from January 1, 2020 to October 20, 2020 to determine epidemiological information related to patients with rheumatic diseases and COVID-19, including clear risk estimate or data that could be converted and extracted. We included 26 observational studies, totaling about 2000 patients with rheumatic diseases of whom were infected with COVID-19. Meta-analysis showed that the risk of COVID-19 infection in rheumatic patients was significantly higher than that in the general population (OR = 1.53, 95% CI 1.24-1.88, P = 0.000). In terms of hospitalization and severe clinical outcomes associated with COVID-19, we found that rheumatic patients showed similar results to the reference population (hospitalization OR = 1.36, 95% CI 0.81-2.29, P = 0.247; admitted to ICU OR = 1.94, 95% CI 0.88-4.27, P = 0.098; death OR = 1.29, 95% CI 0.84-1.97, P = 0.248). The presence of comorbidities, hypertension, lung diseases were significantly associated with the increased risk of COVID-19-related hospitalization in rheumatic patients and anti-TNF drugs were associated with lower hospitalization risk. Older age was related to severe COVID-19. Our meta-analysis indicated that rheumatic patients were at a higher risk of COVID-19 infection but might not lead to a more serious disease process.

Perfluorinated compounds disrupted osmoregulation in Oryzias melastigma during acclimation to hypoosmotic environment.

Perfluorinated compounds (PFCs) are a type of ubiquitous contaminants spreading in the estuarine and coastal areas. Anadromous fish should deal with hypoosmotic challenge with PFCs stress during their migration from seawater to estuaries. However, few studies have been carried out to investigate the adverse impact of PFCs on fish osmoregulation and the underlying mechanism. In this study, Oryzias melastigma, an euryhaline fish model, were exposed to four representative PFC congeners including perfluorobutane sulfonate (PFBS), perfluorooctane sulfonates (PFOS), perfluorooctanoic acid (PFOA), and perfluorododecanoic acid (PFDoA) separately under both seawater and freshwater conditions. Histopathological changes in gills, ion homeostasis, Na+/K+-ATPase (NKA) activity, as well as the expression of related genes was detected upon exposure. Results showed that PFCs induced morphological changes in gills, disturbed the levels of major ions (Na+, Ca2+, Mg2+), and inhibited the NKA activity. Transcriptome analysis in fish gills during the acclimation to freshwater revealed that PFCs influenced the osmoregulation mainly by interfering with the endocrine system, signal transduction, as well as cellular community and motility. Validation with qRT-PCR confirmed that the mRNA expressions of osmoregulatory genes encoding hormones and receptors, as well as ion transmembrane transporters were disturbed by PFCs. Longer chain homolog (PFOS) showed a greater impact on osmoregulation than the shorter chain homolog (PFBS). Within the same carbon chain, sulfonic congener (PFOS) induced more serious injury to gills than carboxylic congener (PFOA). The interaction between PFCs and salinity varied in different adverse outcome. These results help to further understand the mechanism of how PFCs influence osmoregulation and elicit the need to assess the ecological risk of PFCs and other pollutants on anadromous migration.

Activity of Oritavancin and Its Synergy with Other Antibiotics against Mycobacterium abscessus Infection In Vitro and In Vivo.

BACKGROUND: Pulmonary disease caused by Mycobacterium abscessus (M. abscessus) spreads around the world, and this disease is extremely difficult to treat due to intrinsic and acquired resistance of the pathogen to many approved antibiotics. M. abscessus is regarded as one of the most drug-resistant mycobacteria, with very limited therapeutic options. METHODS: Whole-cell growth inhibition assays was performed to screen and identify novel inhibitors. The IC50 of the target compounds were tested against THP-1 cells was determined to calculate the selectivity index, and then time-kill kinetics assay was performed against M. abscessus. Subsequently, the synergy of oritavancin with other antibiotics was evaluated by using checkerboard method. Finally, in vivo efficacy was determined in an immunosuppressive murine model simulating M. abscessus infection. RESULTS: We have identified oritavancin as a potential agent against M. abscessus. Oritavancin exhibited time-concentration dependent bactericidal activity against M. abscessus and it also displayed synergy with clarithromycin, tigecycline, cefoxitin, moxifloxacin, and meropenem in vitro. Additionally, oritavancin had bactericidal effect on intracellular M. abscessus. Oritavancin significantly reduced bacterial load in lung when it was used alone or in combination with cefoxitin and meropenem. CONCLUSIONS: Our in vitro and in vivo assay results indicated that oritavancin may be a viable treatment option against M. abscessus infection.

Baicalein Ameliorates Streptococcus suis-Induced Infection In Vitro and In Vivo.

As an important zoonotic pathogen, Streptococcus suis (S. suis) infection has been reported to be a causative agent for variety of diseases in humans and animals, especially Streptococcal toxic shock-like syndrome (STSLS), which is commonly seen in cases of severe S. suis infection. STSLS is often accompanied by excessive production of inflammatory cytokines, which is the main cause of death. This calls for development of new strategies to avert the damage caused by STSLS. In this study, we found for the first time that Baicalein, combined with ampicillin, effectively improved severe S. suis infection. Further experiments demonstrated that baicalein significantly inhibited the hemolytic activity of SLY by directly binding to SLY and destroying its secondary structure. Cell-based assays revealed that Baicalein did not exert toxic effects and conferred protection in S. suis-infected cells. Interestingly, compared with ampicillin alone, Baicalein combined with ampicillin resulted in a higher survival rate in mice severely infected with S. suis. At the same time, we found that baicalein can be combined with meropenem against MRSA. In conclusion, these results indicate that baicalein has a good application prospect.

Apigenin and Ampicillin as Combined Strategy to Treat Severe Streptococcus suis Infection.

As an important zoonotic pathogen, Streptococcus suis (S. suis) can cause a variety of diseases both in human and animals, especially Streptococcal toxic shock-like syndrome (STSLS), which commonly appears in severe S. suis infection. STSLS is often accompanied by excessive production of inflammatory cytokines, which is the main cause of host death. Therefore, it is urgent to find a new strategy to relieve the damage caused by STSLS. In this study, we found, for the first time, that apigenin, as a flavonoid compound, could combine with ampicillin to treat severe S. suis infection. Studies found that apigenin did not affect the growth of S. suis and the secretion of suilysin (SLY), but it could significantly inhibit the hemolytic activity of SLY by directly binding to SLY and destroying its secondary structure. In cell assays, apigenin was found to have no significant toxic effects on effective concentrations, and have a good protective effect on S. suis-infected cells. More importantly, compared with the survival rate of S. suis-infected mice treated with only ampicillin, the survival rate of apigenin combined with an ampicillin-treated group significantly increased to 80%. In conclusion, all results indicate that apigenin in combination with conventional antibiotics can be a potential strategy for treating severe S. suis infection.

BaeSR activates type VI secretion system expression in porcine extra-intestinal pathogenic Escherichia coli to enhance bacterial resistance to zinc stress.

The two-component system BaeSR is an extra-cytoplasmic stress response system in Escherichia coli, whose function is to be adapted to environmental stress. Recently, we have identified an active type VI secretion system in porcine extra-intestinal pathogenic Escherichia coli PCN033. DNA-protein interactions shows that BaeR directly binds to the promoter region of the T6SS and then induces its expression. Deletion of baeR/baeSR decreased zinc resistance of bacteria. Moreover, T6SS mutant Δhcp1/hcp2/hcp3 is more sensitive than wild type after exposure to external zinc, and complementation of hcp1 largely restored growth defect. Our study uncovers a new regulation mechanism of BaeSR system in response to metal stress. It reveals that BaeR-regulated T6SS is critical for bacteria survival under toxic zinc condition. In conclusion, T6SS contributes to zinc stress resistance in a BaeSR system-dependent manner.

Orphan response regulator Rv3143 increases antibiotic sensitivity by regulating cell wall permeability in Mycobacterium smegmatis.

About one quarter of people worldwide are infected with tuberculosis, and multi-drug resistant tuberculosis (MDR-TB) remains a health threat. It is known that two-Component Signal Transduction Systems (TCSs) of Mycobacterium tuberculosis are closely related to tuberculosis resistance, but the mechanism by which orphan response protein Rv3143 regulates strain sensitivity to drug is still unclear. This study found that Rv3143 overexpression resulted in approximately two-fold increase in Mycobacterium smegmatis antibiotic sensitivity. Transcriptome sequencing indicated that 198 potential genes were regulated by Rv3143, affecting the sensitivity of the strain to rifampicin (RIF). MSMEG_4740 promoter binding with Rv3143, was screened out by surface plasmon resonance (SPR). Rv1524, the homologous gene of MSMEG_4740, belonging to the glycosyltransferase (Gtf) family, was related to cell wall modification. By measuring ethidium bromide (EB) accumulation, we found when Rv3143 or MSMEG_4740, or Rv1524 was overexpressed, the cell wall permeability of Mycobacterium smegmatis was increased. In addition, a combination of Rv3143 and RIF was observed. Our findings provide a new strategy for treating drug-resistant tuberculosis by increasing the expression of Rv3143 to enhance the strain sensitivity to antibiotics.

Enniatin A1, A Natural Compound with Bactericidal Activity against Mycobacterium tuberculosis In Vitro.

Background: Tuberculosis remains a global disease that poses a serious threat to human health, but there is lack of new and available anti-tuberculosis agents to prevent the emergence of drug-resistant strains. To address this problem natural products are still potential sources for the development of novel drugs. Methods: A whole-cell screening approach was utilized to obtain a natural compound enniatin A1 from a natural products library. The target compound's antibacterial activity against Mycobacterium tuberculosis (M. tuberculosis) was evaluated by using the resazurin reduction micro-plate assay (REMA) method. The cytotoxicity of the compound against Vero cells was measured to calculate the selectivity index. The intracellular inhibition activity of enniatin A1 was determined. We performed its time-kill kinetic assay against M. tuberculosis. We first tested its synergistic effect in combination with the first and second-line anti-tuberculosis drugs. Finally, we measured the membrane potential and intracellular ATP levels of M. tuberculosis after exposure to enniatin A1. Results: We identified enniatinA1 as a potential antibacterial agent against M. tuberculosis, against which it showed strong selectivity. Enniatin A1 exhibited a time-concentration-dependent bactericidal effect against M. tuberculosis, and it displayed synergy with rifamycin, amikacin, and ethambutol. After exposure to enniatinA1, the membrane potential and intracellular ATP levels of M. tuberculosis was significantly decreased. Conclusions: Enniatin A1 exhibits the positive potential anti-tuberculosis agent characteristics.

Design and demonstration of an acoustic right-angle bend.

In this paper, a broadband acoustic right-angle bend device in air is designed, fabricated and experimentally characterized. Perforated panels with various hole-sizes are used to construct the bend structure. Both the simulated and experimental results verify that the acoustic beam can be rotated effectively through the acoustic bend in a wide frequency range. This model may have potential applications in some areas such as sound absorption and acoustic detection in elbow pipes.

Integrated genome sequence and linkage map of physic nut (Jatropha curcas L.), a biodiesel plant.

The family Euphorbiaceae includes some of the most efficient biomass accumulators. Whole genome sequencing and the development of genetic maps of these species are important components in molecular breeding and genetic improvement. Here we report the draft genome of physic nut (Jatropha curcas L.), a biodiesel plant. The assembled genome has a total length of 320.5 Mbp and contains 27,172 putative protein-coding genes. We established a linkage map containing 1208 markers and anchored the genome assembly (81.7%) to this map to produce 11 pseudochromosomes. After gene family clustering, 15,268 families were identified, of which 13,887 existed in the castor bean genome. Analysis of the genome highlighted specific expansion and contraction of a number of gene families during the evolution of this species, including the ribosome-inactivating proteins and oil biosynthesis pathway enzymes. The genomic sequence and linkage map provide a valuable resource not only for fundamental and applied research on physic nut but also for evolutionary and comparative genomics analysis, particularly in the Euphorbiaceae.

Multi-channel colorimetric and fluorescent probes for differentiating between cysteine and glutathione/homocysteine.

Three fluorescent probes TP1­3 for thiols were rationally designed and synthesized to distinguish cysteine (Cys) from glutathione (GSH)/homocysteine (Hcy). TP1­3 are almost non-fluorescent and colorless 4-nitro-1,8-naphthalimide derivatives. Upon the substitution of nitro by Cys, TP1­3 were transformed into weakly fluorescent green-emitting 4-amino analogs via highly fluorescent blue-emitting thioether intermediates. The three-channel signaling capability allows discrimination between Cys and GSH/Hcy. The fluorescence intensity at 498 nm was linearly proportional to GSH concentration in the range of 0-20 µM, and the detection limit was 5 × 10(-8) mol L(-1). A good linear relationship between A446/A350 and Cys concentration was found in the range of 0-70 µM, and the detection limit was 2 × 10(-7) mol L(-1). Moreover, TP3 was used for living cell imaging as well as for detecting mercapto-containing proteins.

Antibacterial efficacy and mechanism of Cyprinus carpio chemokine-derived L-10 against multidrug-resistant Escherichia coli infections.

OBJECTIVES: Antimicrobial resistance has raised concerns regarding untreatable infections and poses a growing threat to public health. Rational design of new AMPs is an ideal solution to this threat. METHODS: In this study, we designed, modified, and synthesised an excellent AMP, L-10, based on the original sequence of the Cyprinus carpio chemokine. All experimental data were presented as the mean ± standard deviation (SD), and the two-tailed unpaired T-test method was used to analyze all data. RESULTS: L-10 exhibited excellent antibacterial activity with negligible toxicity and improved the efficacy of a broad class of antibiotics against MDR Gram-negative pathogens, including tetracycline, meropenem, levofloxacin, and rifampin. Mechanistic studies have suggested that L-10 targets the bacterial membrane components, LPS and PG, to disrupt bacterial membrane integrity, thereby exerting antibacterial effects and enhancing the efficacy of antibiotics. Moreover, in animal infection models, L-10 significantly increased the survival rate of infected animals and effectively reduced the tissue bacterial load and inflammatory factor levels. In addition to its direct antibacterial activity, L-10 dramatically reduced pulmonary pathological alterations in a mouse model of endotoxemia and suppressed LPS-induced proinflammatory cytokines in vitro and in vivo. Lastly, L-10 was successfully expressed in Pichia pastoris and maintained antimicrobial activity against MDR Gram-negative pathogens in vivo and in vitro. CONCLUSION: Collectively, these results reveal the potential of L-10 as an ideal candidate against MDR bacterial infections and provide new insights into the design, development, and clinical application of AMPs.

Ultrasound propagation characteristics within the bone tissue of miniature ultrasound probes: implications for the spinal navigation of pedicle screw placement.

Background: The accuracy of pedicle screw fixation is crucial for patient safety. Traditional navigation methods based on computed tomography (CT) imaging have several limitations. Therefore, this study aimed to investigate the ultrasonic propagation characteristics of bone tissue and their relationship with CT imaging results, as well as the potential application of ultrasound navigation in pedicle screw fixation. Methods: The study used three bovine spine specimens (BSSs) and five human vertebral allograft bones (HABs) to progressively decrease the thickness of the cancellous bone layer, simulating the process of pedicle screw perforation. Five unfocused miniature ultrasound probes with frequencies of 2.2, 2.5, 3, 12, and 30 MHz were employed for investigating the ultrasonic propagation characteristics of cancellous and cortical bone through ultrasound transmission and backscatter experiments. The CT features of the bone tissue was obtained with the Skyscan 1174 micro-CT scanner (Bruker, Billerica, MA, USA). Results: The experimental results demonstrated that low-frequency (2-3 MHz) ultrasound effectively penetrated the cancellous bone layer up to a depth of approximately 5 mm, with an attenuation coefficient below 10 dB/cm. Conversely, high-frequency (12 MHz) ultrasound exhibited significant signal attenuation in cancellous bone, reaching up to 55.8 dB/cm. The amplitude of the backscattered signal at the cancellous bone interface exhibited a negative correlation with the bone sample thickness (average r=-0.84), meaning that as the thickness of the cancellous bone layer on the cortical bone decreases, the backscattered signal amplitude gradually increases (P<0.05). Upon reaching the cortical bone interface, there was a rapid surge in echo signal amplitude, up to 8 times higher. Meanwhile, the statistical results indicated a significant correlation between the amplitude of the echo signal and the micro-CT scanning results of bone trabecular structure. Conclusions: Theoretically, using multiple ultrasonic probes (≥3) and regions of interest (ROIs) (≥5) has the potential to provide surgeons with early warning signals for pedicle perforation based on three or more successive increases in echo signal amplitude or a sudden substantial increase. The statistical results indicate a significant correlation between the amplitude of the echo signal and the micro-CT scanning results of bone trabeculae, suggesting the potential use of ultrasound as opposed to CT for real-time intraoperative bone navigation.