Isolation and absolute configuration of alkylpyridine alkaloids from the marine sponge Hippospongia lachne.

Marine sponges are well known as prolific producers of structurally diverse molecules with valuable pharmacological potential. As part of our ongoing program to discover bioactive compounds from marine sponges collected from the Xisha Islands in the South China Sea, a chemical study on the specimens of Hippospongia lachne was conducted. As a result, eight undescribed compounds, including four zwitterionic alkylpyridinium salts, hippospondines A-D (1-4), and four 3-alkylpyridine alkaloids, hippospondines E (5), F (6), and (±)-hippospondine G (7), were isolated from the marine sponge H. lachne, together with one known 3-alkylpyridine alkaloid (8). The undescribed structures were elucidated by HRESIMS, NMR, DP4+ and CP3 probability analysis, and the Snatzke's method. Hippospondines A-D (1-4) represent the rare example of inner salt type alkylpyridinium alkaloid with a farnesyl moiety. Compounds 1-3 and 8 were subjected to cytotoxic and lymphocyte proliferation assays. Compound 3 exhibited a weak promotion effect on the ConA-induced T lymphocyte proliferation.

Isolation, characterization, and genomic analysis of a novel bacteriophage MA9V-1 infecting Chryseobacterium indologenes: a pathogen of Panax notoginseng root rot.

Chryseobacterium indologenes is one of the primary causative agents of root rot of Panax notoginseng, which significantly affected plant growth and caused economic losses. With the increasing incidence of antibiotic-resistant bacterial phytopathogens, phage therapy has been garnered renewed attention in treating pathogenic bacteria. However, the therapeutic potential of phage therapy on root rot of P. notoginseng has not been evaluated. In this study, we isolated a novel lytic phage MA9V-1 infecting C. indologenes MA9 from sewage and monitored the formation of clear and round plaques with a diameter of approximately 0.5-1.5 mm. Phage MA9V-1 exhibited rapid absorption (>75% in 8 min), a latency period of 20 min, and a burst size of 10 particles per cell. Transmission electron microscopy indicated that the phage MA9V-1 is a new myovirus hosting C. indologenes MA9. Sequencing of phage genomes revealed that phage MA9V-1 contained a linear double-stranded DNA genome of 213,507 bp with 263 predicted open reading frames, including phage structure, host lysing, and DNA polymerase/helicase but no genes of tRNA, virulence, and antibiotic resistance. Our proteomic tree and genomic analysis revealed that phage MA9V-1 shares identity with Sphingomonas phage PAU and Tenacibaculum phage PTm1; however, they also showed apparent differences. Further systemic evaluation using phage therapy experiments on P. notoginseng suggested that phage MA9V-1 can be a potential candidate for effectively controlling C. indologenes MA9 infection. Thus, we have presented a novel approach to solving root rot in P. notoginseng.

Corrigendum: The correlation between collagen types and ultrasound feature score in evaluating the vulnerability of carotid artery plaque.

[This corrects the article DOI: 10.3389/fcvm.2021.756424.].

Hipposponols A and B, two new 9, 11-secosterols from the marine sponge Hippospongia lachne de Laubenfels.

Two new 9,11-secosterols, hipposponols A (1) and B (2), together with five known analogues, aplidiasterol B (3), (3ß,5α,6ß)-3,5,6-triol-cholest-7-ene (4), (3ß,5α,6ß,22E)-3,5,6-triol-ergosta-7,22-diene (5), and one pair of inseparable C-24 epimers of (3ß,5α,6ß,22E)-3,5,6-triol-stigmasta-7,22-diene (6/7), were isolated from the marine sponge Hippospongia lachne de Laubenfels. The structures of isolated compounds were extensively elucidated based on HRESIMS and NMR data. Compounds 2 - 5 showed cytotoxicity against PC9 cells with IC50 values ranging from 34.1 ± 0.9 to 38.9 ± 1.0 µM and compound 4 displayed cytotoxicity against MCF-7 cells with IC50 value of 39.0 ± 0.4 µM.

Predictors of ischemic events in patients with unilateral extracranial vertebral artery dissection: A single-center exploratory study.

Objective: Extracranial vertebral artery dissection (EVAD) is one of the main causes of stroke in young and middle-aged patients. However, the diagnosis is challenging. This study aimed to identify the characteristics of EVAD on color duplex ultrasonography (CDU) and high-resolution magnetic resonance imaging (hrMRI), hoping to improve the accuracy and determine the relative contribution of vessel findings and clinical factors to acute ischemic events. Methods: Patients with unilateral EVAD were recruited and divided into ischemia and non-ischemia groups. Clinical features of patients and the lesion location; a variety of signs which indicate dissection, including the presence of an intimal flap, double lumen, intramural hematoma, dissecting aneurysm, intraluminal thrombus, and irregular lumen; and other quantitative parameters of each dissected segment on CDU and hrMRI were reviewed, respectively. Multiple logistic regression was performed to explore the association between clinical, imaging characteristics, and ischemic events in patients with unilateral EVAD. Results: Ninety-six patients with unilateral EVAD who met the inclusion criteria were enrolled during a six-year period. Overall, 41 cases (42.7%) were confirmed as ischemic stroke (n = 40) or transient ischemic attack (n = 1) during the 48 h after the onset of symptoms. Men, infections during the last week, and smoking were more common in the ischemia group. Intraluminal thrombus and occlusion on CDU were more prevalent in patients with cerebral ischemia than in those without (36.6 vs. 5.5%; p < 0.001, and 39.0 vs. 9.1%; p = 0.001, respectively). On hrMRI, intraluminal thrombus and occlusion were also more frequent in the ischemia group than in the non-ischemia group (34.1 vs. 5.5%; p < 0.001, and 34.1 vs. 9.1%; p = 0.003, respectively). In addition, lesion length on hrMRI was significantly longer for patients with ischemia (81.5 ± 41.7 vs. 64.7 ± 30.8 mm; p = 0.025). In multivariable logistic regression analysis, male gender, infections during the last week, and the presence of intraluminal thrombus on CDU and hrMRI were independently associated with acute ischemic events. Conclusion: Male sex, infections during the last week, and the presence of intraluminal thrombus due to dissection are associated with an increased risk of ischemic events in patients with unilateral EVAD.

Texture Analysis Based on Vascular Ultrasound to Identify the Vulnerable Carotid Plaques.

Vulnerable carotid plaques are closely related to the occurrence of ischemic stroke. Therefore, accurate and rapid identification of the nature of carotid plaques is essential. This study aimed to determine whether texture analysis based on a vascular ultrasound can be applied to identify vulnerable plaques. Data from a total of 150 patients diagnosed with atherosclerotic plaque (AP) by carotid ultrasound (CDU) and high-resolution magnetic resonance imaging (HRMRI) were collected. HRMRI is the in vivo reference to assess the nature of AP. MaZda software was used to delineate the region of interest and extract 303 texture features from ultrasonic images of plaques. Following regression analysis using the least absolute shrinkage and selection operator (LASSO) algorithm, the overall cohort was randomized 7:3 into the training (n = 105) and testing (n = 45) sets. In the training set, the conventional ultrasound model, the texture feature model, and the conventional ultrasound-texture feature combined model were constructed. The testing set was used to validate the model's effectiveness by calculating the area under the curve (AUC), accuracy, sensitivity, and specificity. Based on the combined model, a nomogram risk prediction model was established, and the consistency index (C-index) and the calibration curve were obtained. In the training and testing sets, the AUC of the prediction performance of the conventional ultrasonic-texture feature combined model was higher than that of the conventional ultrasonic model and the texture feature model. In the training set, the AUC of the combined model was 0.88, while in the testing set, AUC was 0.87. In addition, the C-index results were also favorable (0.89 in the training set and 0.84 in the testing set). Furthermore, the calibration curve was close to the ideal curve, indicating the accuracy of the nomogram. This study proves the performance of vascular ultrasound-based texture analysis in identifying the vulnerable carotid plaques. Texture feature extraction combined with CDU sonogram features can accurately predict the vulnerability of AP.

New Bioactive Polyacetylenes from the Marine Sponge Petrosia sp.

Three new polyacetylenes, pellynols P (1), Q (2), and R (3) were isolated from the marine sponge Petrosia sp., along with the known compound pellynol H (4). Their structures were determined by analyses of extensive NMR, HR-MS, and ESI-MS/MS data. All compounds displayed potent cytotoxicities against human hepatocellular carcinoma HepG2, human melanoma A375, and human colorectal carcinoma HT29 cell lines with IC50 values at the range of 1.4-4.4 µM.

Interactions Between Phenolic Acids and Microorganisms in Rhizospheric Soil From Continuous Cropping of Panax notoginseng.

Large-scale intensive cultivation has made continuous cropping soil sickness more serious for Panax notoginseng in Yunnan. Autotoxic substances can promote the occurrence of continuous cropping soil sickness. Phenolic acids exert a strong autotoxic effect on P. notoginseng. Based on UPLC-MS/MS, the levels of six phenolic acids with the strongest autotoxicity of P. notoginseng rhizospheric soil were tested. Based on Illumina MiSeq high-throughput sequencing technology, the variation in the microbial diversity in the rhizospheric soil was used as an index to explore the interactions between phenolic acids and the soil microorganisms of the P. notoginseng rhizosphere. (1) Continuous P. notoginseng cropping significantly changed the microbial community structure. Continuous cropping increased bacterial Chao1 index and Shannon index and decreased fungal Shannon index. After P. notoginseng disease, bacterial Shannon index reduced and fungal Chao1 index decreased. (2) Phenolic acid significantly changed the bacterial community structure. VA significantly reduced the bacterial Shannon index. Exogenous p-HA, FA, SA, and VA significantly increased the fungal Chao1 index and p-HA showed the most significant effect. Para-HA affected bacterial specificity, and VA affected fungal specificity. (3) VA was positively correlated with most fungi and bacteria. Para-HA was positively correlated with Lelliottia and Flavobacterium. Para-HA was also positively correlated with plant pathogens (Fusarium and Ilyonectria). Para-HA and VA were able to promote the growth of primary pathogenic bacteria. Thus, p-HA and VA are the main phenolic acid-autotoxin substances in P. notoginseng under continuous cropping. (4) A correlation analysis of soil environmental factors associated with fungal and bacterial communities showed that AK, TN, OM, and HN were most strongly correlated with soil microorganisms. (5) The microorganisms in the rhizosphere of 3-year-old soil planted with P. notoginseng exhibited obvious effects on the degradation of the four phenolic acids. The effect of soil microorganisms on phenolic acids was first-order kinetic degradation with a high degradation rate and a half-life of less than 4.5 h. The results showed that phenolic acids could promote the growth of pathogenic bacteria. And the interaction between rhizospheric soil microorganisms and phenolic acids was the main cause of the disturbance of P. notoginseng rhizosphere microflora.

Phage therapy for refractory periapical periodontitis caused by Enterococcus faecalis in vitro and in vivo.

A phage PEf771 that specifically infects and lyses pathogenic Enterococcus faecalis YN771 in patients with refractory periapical periodontitis was used to investigate resistance against E. faecalis infection in vitro and in vivo. PEf771 completely lysed YN771 within 3 h, with a multiplicity of infection of 1. Compared with ten routinely used clinical antibiotics, PEf771 demonstrated the highest bacteriostatic effect within 72 h. The antibacterial effect of PEf771 on extracted teeth within 72 h was better than that of conventional root canal disinfectants such as camphorated phenol, formaldehyde cresol solution, and Ca(OH)2 (P < 0.05) within 72 h. Using E. faecalis, intraperitoneal and periapical infection models were established using Sprague Dawley (SD) rats. The results showed that all SD rats inoculated with 9.6 × 1011 CFU/mL E. faecalis YN771 or 2.9 × 1011 CFU/mL E. faecalis RYN771 died within 8 h. Additionally, all SD rats inoculated with YN771 and treated with antibiotics died within 72 h. Although SD rats inoculated with RYN771 and treated with antibiotics survived for 72 h, the pathological anatomy of these rats showed purulent discharge, numerous pus and blood-filled ascites, and extensive liver abscesses. Notably, YN771 rats treated with PEf771 and RYN771 rats treated with RPEf771 survived for 72 h, and their pathological anatomy showed that the liver, kidneys, intestine, and mesenteries were normal. Computed tomography analysis of SD rats infected with periapical periodontitis showed pathological changes in experimental teeth inoculated with YN771, despite undergoing a normal root canal treatment. Contrastingly, none of the experimental teeth exhibited root periapical inflammation following PEf771 treatment. Hematoxylin and eosin staining revealed a gap between the periodontal ligament and the cementum of experimental teeth, whereas PEf771-treated teeth exhibited normal results. These findings suggested that phage therapy using PEf771 might effectively prevent E. faecalis infection after root canal treatment.Key points• Compared with common clinical antibiotics, PEf771 showed the highest antibacterial.• The liver, kidney, intestine, and mesentery of SD rats treated with PEf771 were normal.• Phage therapy can effectively prevent E. faecalis YN771 and RYN771 infection.

Evaluation of right-to-left shunt on contrast-enhanced transcranial Doppler in patent foramen ovale-related cryptogenic stroke: Research based on imaging.

BACKGROUND: Cardiogenic embolism caused by patent foramen ovale (PFO) is a common etiology of cryptogenic stroke (CS), particularly in young and middle-aged patients. Studies about right-to-left shunt (RLS) detection using contrast-enhanced transcranial Doppler (c-TCD) are numerous. According to the time phase and number of microbubbles detected on c-TCD, RLS can be classified and graded. We hypothesized that the characteristics of an infarction lesion on diffusion-weighted imaging differs when combining the type and grade of RLS on c-TCD in patients with PFO-related CS. AIM: To explore the characteristics of infarction lesions on diffusion-weighted imaging when combining the RLS type and grade determined by c-TCD. METHODS: We retrospectively evaluated CS patients from August 2015 to December 2019 at a tertiary hospital. In total, 111 PFO-related CS patients were divided according to whether RLS was permanent (microbubbles detected both at resting state and after the Valsalva maneuver) or latent (microbubbles detected only after the Valsalva maneuver) on c-TCD. Each group was subdivided into small, mild and large RLS according to the grade of shunt on c-TCD. A normal control group was composed of 33 patients who suffered from simple dizziness. Intragroup and intergroup differences were analyzed in terms of clinical, laboratory and diffusion-weighted imaging lesion characteristics. The correlation between RLS grade evaluated by c-TCD and size of PFO determined by transesophageal echocardiography were also analyzed. RESULTS: In 111 patients with PFO-related CS, 68 had permanent RLS and 43 had latent RLS. Clinical characteristics and laboratory tests were not significantly different among the permanent RLS, latent RLS and normal control groups. The proportion of patients with multiple territory lesions in the permanent RLS group (50%) was larger than that in the latent RLS group (27.91%; P = 0.021). Posterior circulation was more likely to be affected in the latent RLS group than in the permanent RLS group (30.23% vs 8.82%, P = 0.004). Permanent-large and latent-large RLS were both more likely to be related to multiple (P trend = 0.017 and 0.009, respectively), small (P trend = 0.035 and 0.006, respectively) and cortical (P trend = 0.031 and 0.033, respectively) lesions. The grade of RLS evaluated by c-TCD was correlated to the size of PFO determined by transesophageal echocardiography (r = 0.758, P < 0.001). CONCLUSION: Distribution of the infarct suggested the possible type of RLS. Multiple, small and cortical infarcts suggest large RLS induced by a large PFO.

Chemical and biological diversity of new natural products from marine sponges: a review (2009-2018).

Marine sponges are productive sources of bioactive secondary metabolites with over 200 new compounds isolated each year, contributing 23% of approved marine drugs so far. This review describes statistical research, structural diversity, and pharmacological activity of sponge derived new natural products from 2009 to 2018. Approximately 2762 new metabolites have been reported from 180 genera of sponges this decade, of which the main structural types are alkaloids and terpenoids, accounting for 50% of the total. More than half of new molecules showed biological activities including cytotoxic, antibacterial, antifungal, antiviral, anti-inflammatory, antioxidant, enzyme inhibition, and antimalarial activities. As summarized in this review, macrolides and peptides had higher proportions of new bioactive compounds in new compounds than other chemical classes. Every chemical class displayed cytotoxicity as the dominant activity. Alkaloids were the major contributors to antibacterial, antifungal, and antioxidant activities while steroids were primarily responsible for pest resistance activity. Alkaloids, terpenoids, and steroids displayed the most diverse biological activities. The statistic research of new compounds by published year, chemical class, sponge taxonomy, and biological activity are presented. Structural novelty and significant bioactivities of some representative compounds are highlighted. Marine sponges are rich sources of novel bioactive compounds and serve as animal hosts for microorganisms, highlighting the undisputed potential of sponges in the marine drugs research and development. Supplementary Information: The online version contains supplementary material available at 10.1007/s42995-022-00132-3.

Autoinducer-2-mediated quorum-sensing system resists T4 phage infection in Escherichia coli.

In response to the restriction of nutrients and predation by natural enemies, bacteria have evolved complex coping strategies to ensure the reproduction and survival of individual species. Quorum sensing (QS) is involved in the bacterial response to phage predation and regulation of cellular metabolism. However, to date, no clear evidence exists regarding the involvement of autoinducer-2 (AI-2)-mediated QS systems in Escherichia coli in response to the challenges of nutrient restriction and phage infection. In this study, the role of the AI-2-mediated QS system in resisting T4 phage infection and regulating cell mechanisms in E. coli was revealed for the first time. This effect of the AI-2-mediated QS was achieved by simultaneously downregulating the T4 absorption site and carbon and glucose metabolism. Additionally, we found that lsrB, a metabolic brake, participates in AI-2-mediated regulation and maintenance of the normal metabolic balance of cells. The novel phage defense strategy and regulation and maintenance of cellular metabolism effectively limited the expansion of the phage population.

The Correlation Between Collagen Types and Ultrasound Feature Score in Evaluating the Vulnerability of Carotid Artery Plaque.

Objectives: To investigate whether ultrasound score has clinical value in identifying carotid artery-vulnerable plaque and the impacts of collagen distribution on the stability of plaque. Materials and Methods: Standard carotid artery ultrasound examinations were performed in 51 patients with carotid artery plaques before carotid endarterectomy. Hematoxylin-eosin staining and Sirius red-picric acid staining of plaque sections were performed to analyze the pathological features and collagen distribution. All plaques were classified into vulnerable and stable groups by pathological features. Ultrasound scores, cap thickness, and the ratios of different collagen types were recorded and analyzed between two groups and different parts of plaques. Results: Ultrasound scores of the vulnerable group were higher than those of the stable group (4.35 ± 1.23 vs. 2.09 ± 1.04, P = 0.001). AUC was 0.894 (best cutoff point three) in differentiating vulnerable and stable plaques. Compared with the stable group, the fibrous caps of the vulnerable group were thinner (P = 0.012); the area ratios of collagen type I to all collagen in the vulnerable group were lower (P = 0.033); however, the area ratios of collagen type IV to all collagen were higher (P = 0.026). Compared with downstream shoulders, the ultrasound scores of upstream shoulders of plaque were higher (P = 0.001), the fibrous caps of upstream shoulders were thinner (P = 0.001), and the area ratios of collagen type I to all collagen were lower (P = 0.022). Conclusion: Ultrasound score could have a clinical value in identifying vulnerable carotid artery plaque, and the collagen distribution could impact the stability of plaques, especially collagen type I and type IV. The results also prompted that the upstream shoulders were more vulnerable than the downstream shoulders.

Carbon dots derived from Fusobacterium nucleatum for intracellular determination of Fe3+ and bioimaging both in vitro and in vivo.

Intracellular Fe3+ amount is one of the critical determinants of human health. The development of simple and effective probes for the quantitative detection of Fe3+in vivo is of great significance for the early diagnosis of disease or disorder associated with iron deficiency or overload. In this study, remarkable carbon dots, which can serve as a biosensor for efficient intracellular Fe3+ detection, were synthesized by hydrothermal carbonization of Fusobacterium nucleatum, an anaerobic bacterium. The achieved F. nucleatum-carbon dots (Fn-CDs) possessed the features of strong fluorescence, high stability and excellent biocompatibility. The obtained Fn-CDs could easily internalize into both plant cells and human cells with excellent ability for cell tracking and biomedical labeling. The fluorescence of Fn-CDs could still remain for another 24 hours after penetrating into cells. Furthermore, the fluorescent Fn-CDs were very sensitive to the presence of Fe3+ ions even in cells, exhibiting great promising applications in in vivo detection of Fe3+ ions. In addition, the Fn-CDs posed no harm to the mice, being circulated and excreted within a short time, making the Fn-CDs an excellent candidate for bioimaging and biosensing in vivo.

Carbon dots derived from kanamycin sulfate with antibacterial activity and selectivity for Cr6+ detection.

Among antibacterial nanomaterials, carbon dots (CDs) have attracted much attention because of their unique physical and chemical properties and good biosafety. In this study, kanamycin sulfate (Kan), a broad-spectrum antibiotic, was used to synthesize novel carbon dots (CDs-Kan) by a one-step hydrothermal method. CDs-Kan showed good inhibitory effects on Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus. Further, scanning electron microscopy revealed that treatment with CDs-Kan and Kan resulted in the same phenomena. In particular, the morphologies of S. aureus cells treated with CDs-Kan and Kan became smaller and irregular, whereas the surfaces of E. coli cells protruded and formed vesicles. These results indicated that CDs-Kan was shown to retain the good antibacterial activity of Kan as well as its main bactericidal functional groups, namely, the amino sugar and amino cyclic alcohol, We refer to this phenomenon as the "preservation property". We also found that CDs-Kan has good biocompatibility and nontoxic properties. Moreover, CDs-Kan was successfully applied to the biological imaging of fungi and plant cells. In addition, CDs-Kan could be used as a fluorescent probe for the quick, sensitive, and selective detection of Cr6+. Therefore, CDs-Kan not only retained the good bacteriostatic properties of Kan but also expanded its application in bioimaging and biosensors.

Serratia marcescens-derived fluorescent carbon dots as a platform toward multi-mode bioimaging and detection of p-nitrophenol.

Carbon dots (CDs) have excellent application prospects in various fields such as fluorescent dyes, but expanding their application, especially in bioimaging and the detection of organic pollutants, is still a major research objective. In this study, fluorescent CDs were successfully synthesized via the hydrothermal method using Serratia marcescens KMR-3. The platform based on CDs-KMR3 exhibited excellent stability, good biocompatibility, and low biotoxicity, and can be effectively applied to the imaging of bacteria, fungi, plant cells, protozoa and mammalian cells, and can specifically stain the membranes of all tested cells. In this study, for the first time, bacteria-derived CDs were used to image the representative species of organisms ranging from lower-order to higher-order organisms, thereby proving the feasibility of the application of CDs in the fluorescence imaging of Paramecium caudatum. Additionally, CDs-KMR3 can rapidly diffuse into all the parts of the leaf through diffusion into the veins and intercellular interstitium in response to the induction of transpiration. Moreover, the data illustrate that CDs-KMR3 are likely to enter the digestive tracts of microworms by ingestion through the oral cavity and pharynx, and spread to the pseudocoelom and somatic cells, and finally to be excreted from microworms through the anus. Furthermore, this platform can be utilized as fluorescent probes for the rapid and highly selective detection of p-nitrophenol (p-NP). Moreover, this study contributed to the increased application of bacteria-derived CDs in bioimaging and detection of p-NP.

Novel fluorescent nitrogen-doped carbon dots derived from Panax notoginseng for bioimaging and high selectivity detection of Cr6.

Carbon dots (CDs) and photoluminescent carbon dots (Pn-CDs) are promising nanomaterials due to their bioimaging applications and have attracted considerable attention because of their excellent stability, good biocompatibility, and low biotoxicity. Here, the Pn-CDs and highly fluorescent nitrogen-doped CDs (Pn N-CDs) derived from Panax notoginseng were successfully synthesized by a simple hydrothermal method. Pn N-CDs exhibit optical properties and stability superior to those of Pn-CDs and can be better used as fluorescent dyes and probes in biological imaging. The obtained Pn N-CDs can be effectively applied to the imaging of bacteria, fungi, plant cells, and protozoa. In addition, Pn N-CDs can perform specific staining on the membranes of all tested cells. The in vivo imaging of mice revealed that Pn N-CDs exhibit nontoxicity and good biocompatibility and biodistribution. Furthermore, Pn N-CDs can be utilized as fluorescent probes for the rapid and highly selective detection of Cr6+. Hence, a simple, cost-effective, scalable, and green synthetic approach based on traditional Chinese medicine-derived CDs can be used to develop biolabeling, membrane targeting, and optical sensing probes.

Evaluation of Carotid Plaque Rupture and Neovascularization by Contrast-Enhanced Ultrasound Imaging: an Exploratory Study Based on Histopathology.

A significant portion of ischemic stroke is on account of emboli caused by fibrous cap rupture of vulnerable plaque with intraplaque neovascularization as a significant triggering factor to plaque vulnerability. Contrast-enhanced ultrasound (CEUS) could offer detailed information on plaque surface and intraplaque microvascular. This study aims to comprehensively assess the value of CEUS for the detection of plaque rupture and neovascularization in histologically verified plaques that had been removed from the patients who had undergone carotid endarterectomy (CEA). Fifty-one consecutive subjects (mean age, 67.0 ± 6.5 years; 43 [84.3%] men) scheduled for CEA were recruited. Standard ultrasound and CEUS were performed prior to surgery. Based on the direction of the contrast agents that diffuse within the plaques, plaques were divided as "inside-out" direction (contrast agents diffuse from the artery lumen towards the inside of the plaque) and non-inside-out direction. Plaque enhancement was assessed by using a semi-quantitative grading scale (grade 1: no enhancement; grade 2: moderate enhancement; grade 3: extensive enhancement). Plaques were evaluated for histopathologic characteristics according to Oxford Plaque Study (OPS) standard postoperative. Intraplaque neovascularization as manifested by the appearance of CD34-positive microvessels was characterized in terms of microvessel density (MVD), microvessel area (MVA), and microvessel shape (MVS). In 51 plaques, the sensitivity, specificity, positive, and negative predictive values of contrast agent inside-out direction diffusion for the detection of plaque fibrous cap rupture were 87.5%, 92.6%, 91.3%, and 89.3%, respectively. The incidence of cap rupture was significantly higher in contrast agent inside-out direction diffusion than non-inside-out direction diffusion (73.9% vs 25.0%, p < 0.001), and inside-out direction diffusion did exhibit higher frequency of vulnerable plaques (OPS grades 3-4) (95.7% vs 53.6%, p = 0.001). Multivariate logistic regression analysis revealed the contrast agent inside-out direction diffusion as an independent correlate to plaque rupture (OR 8.5, 95% CI 2.4-30.1, p = 0.001). With increasing plaque enhancement, plaque MVD (p < 0.001), plaque MVA (p = 0.012), and percentage of highly irregular-shaped microvessels increased (p < 0.001). Contrast agent inside-out direction diffusion could indicate plaque rupture. The increase in plaque enhancement paralleled increased, larger, and more irregular-shaped microvessels, which may suggest an increased risk of plaque vulnerability.

Applications of hydrothermal synthesis of Escherichia coli derived carbon dots in in vitro and in vivo imaging and p-nitrophenol detection.

Carbon dots (CDs) have broad prospective applications in various fields, and expanding the applications of fluorescent CDs, especially for CDs derived from bacteria, is a major research goal. In this study, novel CDs derived from Escherichia coli BW25113 (WT) were successfully synthesized via a one-step hydrothermal method. Unlike previously developed CDs-E. coli, CDs-WT can be used for microbial imaging of both live and dead cells. We demonstrated the biocompatibility, excellent penetrability, and nontoxic characteristics of CDs-WT for use as fluorescent probes for bioimaging both in vitro and in vivo. Importantly, we provide the first demonstration of CDs-WT distribution in various organs of mice, including the ability to cross the blood-brain barrier and the potential for rapid excretion through the intestines. Additionally, CDs-WT can be instantly utilized as a fluorescent probe for the highly selective and rapid detection of p-nitrophenol (p-NP) by the inner filter effect, with a limit of detection for p-NP of 11 nM, the lowest value reported to date. Hence, our results demonstrate the feasibility of p-NP detection and extend the bio-imaging applications of CDs prepared from bacteria.

Bacteria-derived fluorescent carbon dots for highly selective detection of p-nitrophenol and bioimaging.

p-Nitrophenol (p-NP) pollutants are widely present in soil and aquatic environments and can seriously impair the health of living beings. Hence, a rapid, sensitive, and selective method for p-NP detection is urgently needed. Herein, for the first time, we successfully synthesized fluorescent carbon dots (CDs) from Bacillus cereus (BC) via a one-step hydrothermal process. The obtained CDs-BC can be applied as a rapid, highly selective, and sensitive sensor for p-NP detection. The fluorescence quenching efficiency of the CD-BC sensor exhibited excellent linear responses with p-NP concentrations at both 0.3-6.5 µM and 6.5-30 µM, with a detection limit of 0.11 µM. The mechanism of p-NP detection is based on the inner filter effect (IFE). Preliminary bacteria, cell, and animal studies showed that the as-prepared CDs-BC possess high photostability, excellent biocompatibility, low or no biotoxicity, and multicolor fluorescence emission properties; furthermore, they can be rapidly excreted from the body of mice, which suggests their potential for applications in the biomedical field.