Comparison of the effectiveness of probiotic supplementation in glucose metabolism, lipid profile, inflammation and oxidative stress in pregnant women.

Objective: The optimal probiotic supplementation in pregnant women has not been thoroughly evaluated. By employing a network meta-analysis (NMA) approach, we compared the effectiveness of different probiotic supplementation strategies for pregnant women. Methods: A comprehensive search across multiple databases was performed to identify studies comparing the efficacy of probiotic supplements with each other or the control (placebo) among pregnant women. Results: This NMA, including 32 studies, systematically evaluated 6 probiotic supplement strategies: Lactobacillus, Lacticaseibacillus rhamnosus and Bifidobacterium (LRB), Lactobacillus acidophilus and Bifidobacterium (LABB), Lactobacillus acidophilus, Lacticaseibacillus casei, and Bifidobacterium bifidum (LLB), multi-combination of four probiotics (MP1), and multi-combination of six or more probiotics (MP2). Among these strategies, LLB, MP1, and MP2 all contain LABB. The NMA findings showed that MP1 was the most effective in reducing fasting blood sugar (FBS) (surface under the cumulative ranking curve [SUCRA]: 80.5%). In addition, MP2 was the most efficacious in lowering the homeostasis model assessment of insulin resistance (HOMA-IR) (SUCRA: 89.1%). LABB was ranked as the most effective in decreasing low-density lipoprotein cholesterol (LDLC) (SUCRA: 95.5%), total cholesterol (TC) (SUCRA: 95.5%), and high-sensitivity C-reactive protein (hs-CRP) (SUCRA: 94.8%). Moreover, LLB was ranked as the most effective in raising total antioxidant capacity (TAC) (SUCRA: 98.5%). Conclusion: Multi-combination of probiotic strains, especially those strategies containing LABB, may be more effective than a single probiotic strain in glycolipid metabolism, inflammation, and oxidative stress of pregnant women.

Blood Group Antigen A Carriers Exhibit an Extended Progression-Free Survival with no more Immune-Related Adverse Events.

Extensive investigations have been conducted regarding the potential correlation between blood type and the immune system, as well as cancer risk in the Southern Chinese population. However, the prognostic value of the blood group and its genetic determinants in the context of immune checkpoint inhibitor (ICI) treatment remains unclear. Therefore, the associations between the ABO blood group and its single nucleotide polymorphisms (SNPs) were examined in relation to ICI treatment outcomes in 370 eligible patients with cancer. This approach allowed us to derive the blood group from the SNPs responsible for blood group determination. In the discovery cohort (N = 168), antigen A carriers (blood types A and AB) exhibited an extended progression-free survival (PFS; hazard ratio (HR) = 0.58, 95% confidence interval (CI) = 0.34-0.98). The association results from the SNP-derived blood were consistent with those from the measured blood group. In the validation cohort (N = 202), Cox regression analysis revealed that the antigen A carriers (rs507666 AA+GA genotype carriers) experienced significantly extended PFS compared with the non-antigen A carriers (HR = 0.61, 95% CI = 0.40-0.93). Therefore, a longer PFS was observed in antigen A carriers (P value = 0.003, HR = 0.60, 95% CI = 0.44-0.84). Furthermore, haplotype 2 carriers (rs507666 GA and rs659104 GG) demonstrated both extended PFS and improved overall survival. Notably, the presence of antigen A was not associated with the occurrence of overall immune-related adverse events (irAEs) or organ-specific toxicity. In summary, our findings revealed that antigen A carriers did not experience a higher incidence of irAEs while exhibiting better immunotherapy efficacy.

A magnetic resonance imaging-based decision-making tool for predicting complex anal fistulas healing in the early postoperative period.

BACKGROUND: Magnetic resonance imaging (MRI) has excellent accuracy in diagnosing preoperative lesions before anal fistula surgery. However, MRI is not good in identifying early recurrent lesions and effective methods for quantitative assessment of fistula healing are still warranted. This retrospective study aimed to develop and validate a specific MRI-based nomogram model to predict fistula healing during the early postoperative period. METHODS: Patients with complex cryptoglandular anal fistulas who underwent surgery between January 2017 and October 2020 were included in this study. MRI features and clinical parameters were analyzed using univariate and multivariate logistic regression analysis. A nomogram for predicting fistula healing was constructed and validated. RESULTS: In total, 200 patients were included, of whom 186 (93%) were male, with a median age of 36 (18-65) years. Of the fistulas, 58.5% were classified as transsphincteric and 19.5% as suprasphincteric. The data were randomly divided into the training cohort and testing cohort at a ratio of 7:3. Logistic analysis revealed that CNR, ADC, alcohol intake history, and suprasphincteric fistula were significantly correlated with fistula healing. These four predictors were used to construct a predictive nomogram model in the training cohort. AUC was 0.880 and 0.847 for the training and testing cohorts, respectively. Moreover, the decision and calibration curves showed high coherence between the predicted and actual probabilities of fistula healing. CONCLUSIONS: We developed a predictive model and constructed a nomogram to predict fistula healing during the early postoperative period. This model showed good performance and may be clinically utilized for the management of anal fistulas.

Geraniol attenuates virulence factors by inhibiting quorum sensing of Pseudomonas aeruginosa.

Pseudomonas aeruginosa is a ubiquitous opportunistic pathogen that can cause severe respiratory tract infections. Geraniol, a chemical component of essential oils, has antimicrobial and anti-inflammatory activities, along with low toxicity. However, the effect and mechanism of geraniol against P. aeruginosa virulence factors are rarely studied. In this study, we investigated the quorum sensing (QS) inhibitory effects and mechanisms of geraniol against P. aeruginosa PAO1, using physiological and biochemical techniques, quantitative reverse transcription polymerase chain reaction, and transcriptomics. Geraniol slightly affected P. aeruginosa PAO1 growth, prolonged the lag phase, and delayed growth periods in a concentration-dependent manner. Geraniol inhibited three QS systems of P. aeruginosa, las, rhl, and pqs by suppressing the expression level of their key genes, including the three signal synthetase encoding genes of lasI, rhlI, and pqsABCDEH, and the corresponding signal receptor encoding genes of lasR, rhlR, and pqsR. Geraniol also suppressed certain virulence genes regulated by these three QS systems, including rhlABC, lasAB, lecAB, phzABMS, and pelABG, resulting in the attenuation of the related virulence factors, rhamnolipids, exoprotease LasA, elastase, lectin, pyocyanin, and biofilm. In conclusion, geraniol can suppress the virulence factors of P. aeruginosa PAO1 by inhibiting the three QS systems of las, rhl, and pqs. This study is significant for improving the treatment of bacterial infections caused by P. aeruginosa.

Multidimensional evaluation of teaching strategies for pharmacology based on a comprehensive analysis involving 21,269 students.

Background: Given the limitations of traditional pharmacology pedagogical method, diverse novel teaching methods have been widely explored. In this study, we performed a network meta-analysis (NMA) to evaluate the effects of different strategies in pharmacology education. Methods: Literature databases were searched from their inception to November 2022, and the studies were screened according to predefined inclusion and exclusion criteria to extract important information. Outcomes, including theoretical test scores, experimental test scores, subjective test scores, satisfaction scores, and the proportion of satisfaction, were analyzed using R software (version 3.6.1) and STATA (version 15). The NMA was conducted with a random-effects model under the Bayesian framework to calculate odds ratios (ORs) or mean differences (MDs) with associated 95% credible intervals (95% CIs). Surface under the cumulative ranking curve (SUCRA) probability values were calculated to rank the teaching methods examined. Results: A total of 150 studies involving 21,269 students were included. This NMA systematically evaluated 24 teaching strategies, such as problem-based learning (PBL), team-based learning (TBL), case-based learning (CBL) and flipped classrooms (FC), etc., The results of the NMA showed that, PBL combined with CBL was most likely to improve students' theoretical and subjective test scores (SUCRA = 75.49 and 98.19%, respectively), TBL was most likely to improve the experimental test score (SUCRA = 92.38%) and the satisfaction score (SUCRA = 88.37%), while FC had the highest probability of being the best option for improving the proportion of satisfaction (SUCRA = 84.45%). Conclusion: The current evidence indicates that TBL, PBL combined with CBL, and FC might be optimal strategies for pharmacology education since they have a more beneficial effect on students.

Pseudomonas aeruginosa heteroresistance to levofloxacin caused by upregulated expression of essential genes for DNA replication and repair.

Pseudomonas aeruginosa (P. aeruginosa), a common cause of severe chronic infections, has developed heteroresistance to several antibiotics, thus hindering successful treatment. In this study, we aimed to investigate the characteristics and mechanisms underlying levofloxacin (LVX) heteroresistance in P. aeruginosa PAS71 and PAS81 clinical isolates using a combination of physiological and biochemical methods, bacterial genomics, transcriptomics, and qRT-PCR. The six P. aeruginosa strains, namely PAS71, PAS72, PAS81, PAS82, ATCC27853, and PAO1, were studied. The Kirby-Bauer (K-B), minimum inhibitory concentration (MIC) test, and population analysis profile (PAP) experimental results showed that PAS71, PAS81, ATCC27853, and PAO1 were heteroresistant to LVX, with MIC of 0.25, 1, 0.5, and 2 µg/ml, respectively; PAS72 and PAS82 were susceptible to LVX with a MIC of 0.25 and 0.5 µg/ml, respectively. The resistance of PAS71 and PAS81 heteroresistant subpopulations was unstable and had a growth fitness cost. Genomic and transcriptomic results proved that the unstable heteroresistance of PAS71 and PAS81 was caused by elevated expression of essential genes involved in DNA replication and repair, and homologous recombination, rather than their genomic single-nucleotide polymorphism (SNP) and insertion-deletion (InDel) mutations. Additionally, PAS71 and PAS81 enhanced virulence and physiological metabolism, including bacterial secretion systems and biosynthesis of siderophore group nonribosomal peptides, in response to LVX stress. Our results suggest that the upregulation of key genes involved in DNA replication and repair, and homologous recombination causes unstable heteroresistance in P. aeruginosa against LVX. This finding provides novel insights into the occurrence and molecular regulation pathway of P. aeruginosa heteroresistant strains.

Diallyl sulfide from garlic suppresses quorum-sensing systems of Pseudomonas aeruginosa and enhances biosynthesis of three B vitamins through its thioether group.

Diallyl sulfide (DAS) and diallyl disulfide (DADS), two constituents of garlic, can inhibit quorum sensing (QS) systems of Pseudomonas aeruginosa. However, the differences in the mechanism of QS inhibition between DAS and DADS, and the functional chemical groups of these sulfides that contribute in QS inhibition have not been elucidated yet. We assumed that the sulfide group might play a key role in QS inhibition. To prove this hypothesis and to clarify these unsolved problems, in this study, we synthesized diallyl ether (DAE), and compared and investigated the effects of DAS and DAE on the growth and production of virulence factors, including Pseudomonas quinolone signal (PQS), elastase and pyocyanin, of P. aeruginosa PAO1. Transcriptome analysis and qRT-PCR were used to compare and analyse the differentially expressed genes between the different treatment groups (DAS, DAE and control). The results indicated that DAS did not affect the growth dynamics of P. aeruginosa PAO1; however, DAS inhibited transcription of most of the QS system genes, including lasR, rhlI/rhlR and pqsABCDE/pqsR; thus, biosynthesis of the signal molecules C4 -HSL (encoded by rhlI) and PQS (encoded by pqsABCDE) was inhibited. Furthermore, DAS inhibited the transcription of virulence genes regulated by the QS systems, including rhlABC, lasA, lasB, lecA and phzAB, phzDEFG, phzM and phzS that encode for rhamnolipid, exoprotease, elastase, lectin and pyocyanin biosynthesis respectively. DAS also enhanced the expression of the key genes involved in the biosynthesis of three B vitamins: folate, thiamine and riboflavin. In conclusion, DAS suppressed the production of some virulence factors toxic to the host and enhanced the production of some nutrition factors beneficial to the host. These actions of DAS may be due to its thioether group. These findings would be significant for development of an effective drug to control the virulence and pathogenesis of the opportunistic pathogen P. aeruginosa.

The KNRL nuclear receptor controls hydrolase-mediated vitellin breakdown during embryogenesis in the brown planthopper, Nilaparvata lugens.

Vitellin (Vn) homeostasis is central to the fecundity of oviparous insects. Most studies have focused on the synthesis and transportation of Vn as a building block for developing eggs during vitellogenesis; however, less is known about how the utilization of this nutrient reserve affects embryonic development. Here, we show that the single ortholog of the knirps and knirps-like nuclear receptors, KNRL, negatively regulates Vn breakdown by suppressing the expression of hydrolase genes in the brown planthopper, Nilaparvata lugens. KNRL was highly expressed in the ovary of adult females, and knockdown of KNRL by RNA interference resulted in the acceleration of Vn breakdown and the inhibition of embryonic development. Transcriptome sequencing analysis revealed that numerous hydrolase genes, including cathepsins and trypsins were up-regulated after KNRL knockdown. At least eight of the nine significantly enriched Gene Ontology terms for the up-regulated genes were in proteolysis-related categories. The expression levels of five selected trypsin genes and the enzymatic activities of trypsin in the embryos were significantly increased after KNRL knockdown. Moreover, trypsin injection prolonged egg duration, delayed embryonic development, accelerated Vn breakdown and severely reduced egg hatchability, a pattern similar to that observed in KNRL-silenced N. lugens. These observations suggest that KNRL controls Vn breakdown in embryos via the transcriptional inhibition of hydrolases. Generally, this study provides a foundation for understanding how embryo nutrient reserves are mobilized during embryogenesis and identifies several genes and pathways that may prove valuable targets for pest control.

Diallyl disulfide from garlic oil inhibits Pseudomonas aeruginosa virulence factors by inactivating key quorum sensing genes.

Garlic oil can disrupt the quorum sensing (QS) pathways of the opportunistic pathogen Pseudomonas aeruginosa; however, the underlying mechanisms for this effect are unclear. Diallyl disulfide (DADS) is one of the most abundant sulfur-containing compounds in garlic oil. This study investigated the effects of DADS on the growth, virulence factor production (elastase, pyocyanin, biofilm, and swarming motility), and essential gene expression of P. aeruginosa PAO1, particularly as they apply to QS and virulence. DADS at 1.28 mg/mL did not affect P. aeruginosa PAO1 growth, although it decreased elastase and pyocyanin production, biofilm formation, and swarming motility. Each of these phenomena is regulated by the three QS systems of P. aeruginosa PAO1 (las, rhl, and pqs). Real-time q-PCR revealed that DADS down-regulated the transcription levels of several important QS genes (lasI, lasR, rhlI, rhlR, pqsA, and pqsR) in the three systems. Furthermore, the transcription levels of QS-regulated virulence genes were also down-regulated. The lasB gene, encoding LasB elastase, is co-regulated by the las, rhl, and pqs systems, and thus the down-regulation of genes across the three systems further down-regulated lasB. Additionally, phzM (encoding pyocyanin), pslB (responsible for the production of a biofilm matrix polysaccharide), and chiC (encoding chitinase) were positively activated by LasR, and a decrease in lasR transcription further down-regulated the transcription of phzM, pslB, and chiC. Hence, DADS inhibits P. aeruginosa PAO1 virulence factors by inactivating the transcription of key genes across three different QS systems.

Diallyl Disulfide From Garlic Oil Inhibits Pseudomonas aeruginosa Quorum Sensing Systems and Corresponding Virulence Factors.

Previously, we determined that diallyl disulfide (DADS) from garlic oil can inhibit Pseudomonas aeruginosa PAO1 pathogenic factors by inactivating the transcription of key genes from three quorum sensing (QS) systems (las, rhl, and pqs) based on the effects of DADS on growth, virulence factor production (elastase, pyocyanin, biofilm, and swarming motility), and RNA transcription (real-time q-PCR). To further investigate the mechanisms underlying the inhibition of the three P. aeruginosa QS systems by DADS, high-throughput RNA and proteome sequencing techniques were used to study differences in the transcriptional and proteome expression of P. aeruginosa PAO1 following treatment with DADS. The RNA-seq and proteomic data are available via NCBI Gene Expression Omnibus database with accession number GSE118801 and ProteomeXchange with identifier PXD011144, respectively. The experimental results indicated that all key genes of the three QS systems (las, rhl, and pqs) of P. aeruginosa PAO1 as well as the virulence factors (including exoprotease LasA, elastase LasB, lectin LecA and LecB, pyocyanin biosynthesis, and biofilm formation) regulated by these three QS systems were inhibited. This is consistent with our previous studies on the physiology, biochemistry, and RNA expression of P. aeruginosa treated with DADS. Additionally, our results also indicated that bacterial motility, chemotaxis, and two-component systems were inhibited by DADS treatment. All these changes abolish the sensitivity of P. aeruginosa PAO1 to environmental stimuli and cause the cells to be in a state of passivation. Further research is needed to determine how QS systems regulate these functions. Our findings could potentially contribute to the treatment and control of P. aeruginosa infection, virulence, and pathogenicity.

The dynamics and mechanism of the antimicrobial activity of tea tree oil against bacteria and fungi.

Tea tree oil (TTO) is a yellow liquid extracted from Melaleuca alternifolia. Although the antimicrobial activity of TTO has been known for a long time, its specific antimicrobial effects and mechanism underlying these remain poorly characterized. The present study investigated the chemical composition of TTO and the dynamics and mechanism of its antimicrobial activities in two bacterial and two fungal strains. Gas chromatography-mass spectrometry analysis identified alkenes and alcohols as the main constituents of TTO. Terpinen-4-ol was the most abundant individual component, accounting for approximately 23 % of the TTO. Poisoned food technique assessment showed that the minimum inhibitory concentrations of TTO for bacterial strains (Escherichia coli and Staphylococcus aureus) and fungal strains (Candida albicans and Aspergillus niger) were 1.08 and 2.17 mg/mL, respectively. Antimicrobial dynamic curves showed that with increasing concentrations of TTO, the rate of cell killing and the duration of growth lag phase increased correspondingly. These data indicated that TTO produced concentration and time-dependent antimicrobial effects. The minimum bactericidal and fungicidal concentrations of TTO were 2.17, 4.34, and 4.34 against E. coli, S. aureus, and C. albicans, respectively. However, A. niger conidia were not completely eradicated, even after 3 days in the presence of 17.34 mg/mL TTO. Transmission electron microscopy images indicated that TTO penetrated the cell wall and cytoplasmic membrane of all the tested bacterial and fungal strains. TTO may also penetrate fungal organelle membrane. These findings indicated that TTO maybe exerts its antimicrobial effects by compromising the cell membrane, resulting in loss of the cytoplasm and organelle damage, which ultimate leads to cell death.

Antifungal activity, kinetics and molecular mechanism of action of garlic oil against Candida albicans.

The antifungal activity, kinetics, and molecular mechanism of action of garlic oil against Candida albicans were investigated in this study using multiple methods. Using the poisoned food technique, we determined that the minimum inhibitory concentration of garlic oil was 0.35 µg/mL. Observation by transmission electron microscopy indicated that garlic oil could penetrate the cellular membrane of C. albicans as well as the membranes of organelles such as the mitochondria, resulting in organelle destruction and ultimately cell death. RNA sequencing analysis showed that garlic oil induced differential expression of critical genes including those involved in oxidation-reduction processes, pathogenesis, and cellular response to drugs and starvation. Moreover, the differentially expressed genes were mainly clustered in 19 KEGG pathways, representing vital cellular processes such as oxidative phosphorylation, the spliceosome, the cell cycle, and protein processing in the endoplasmic reticulum. In addition, four upregulated proteins selected after two-dimensional fluorescence difference in gel electrophoresis (2D-DIGE) analysis were identified with high probability by mass spectrometry as putative cytoplasmic adenylate kinase, pyruvate decarboxylase, hexokinase, and heat shock proteins. This is suggestive of a C. albicans stress responses to garlic oil treatment. On the other hand, a large number of proteins were downregulated, leading to significant disruption of the normal metabolism and physical functions of C. albicans.

Poly (γ-glutamic acid)/beta-TCP nanocomposites via in situ copolymerization: Preparation and characterization.

A series biodegradable poly (γ-glutamic acid)/beta-tricalcium phosphate (γ-PGA/TCP) nanocomposites were prepared which were composed of poly-γ-glutamic acid polymerized in situ with ß-tricalcium phosphate and physiochemically characterized as bone graft substitutes. The particle size via dynamic light scattering, the direct morphological characterization via transmission electron microscopy and field emission scanning electron microscope, which showed that γ-PGA and ß-TCP were combined compactly at 80℃, and the γ-PGA/TCP nanocomposites had homogenous and nano-sized grains with narrow particle size distributions. The water uptake and retention abilities, in vitro degradation properties, cytotoxicity in the simulated medium, and protein release of these novel γ-PGA/TCP composites were investigated. Cell proliferation in composites was nearly twice than ß-TCP when checked in vitro using MC3T3 cell line. We also envision the potential use of γ-PGA/TCP systems in bone growth factor or orthopedic drug delivery applications in future bone tissue engineering applications. These observations suggest that the γ-PGA/TCP are novel nanocomposites with great potential for application in the field of bone tissue engineering.

Antibacterial activity and kinetics of Litsea cubeba oil on Escherichia coli.

Litsea cubeba oil is extracted from the fresh fruits of Litsea cubeba by distillation. In this study, its chemical constituents, antibacterial activity, kinetics and effects against Escherichia coli were studied. Its minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were both 0.125% (v/v) by toxic food method. Moreover, the antibacterial kinetic curves indicated 0.0625% (v/v) of litsea cubeba oil was able to prolong the growth lag phase of E. coli cells to approximate 12 hours while 0.125% (v/v) of litsea cubeba oil was able to kill the cells completely. Furthermore, transmission electron microscope (TEM) observation showed most E. coli cells treated with 0.125% (v/v) of litsea cubeba oil were killed or destroyed severely within 2 hours. The litsea cubeba oil might penetrate and destroy the outer and inner membrane of E. coli cells. Thus many holes and gaps were observed on the damaged cells, which led to their death eventually. The antibacterial effects of litsea cubeba oil mainly attributed to the presence of aldehydes, which accounted for approximately 70% in its whole components analyzed by GC/MS. Based on the antimicrobial properties, litsea cubeba oil would have a broad application in the antimicrobial industry.

Antifungal effect and mechanism of garlic oil on Penicillium funiculosum.

Garlic oil is a kind of fungicide, but little is known about its antifungal effects and mechanism. In this study, the chemical constituents, antifungal activity, and effects of garlic oil were studied with Penicillium funiculosum as a model strain. Results showed that the minimum fungicidal concentrations (MFCs, v/v) were 0.125 and 0.0313 % in agar medium and broth medium, respectively, suggesting that the garlic oil had a strong antifungal activity. The main ingredients of garlic oil were identified as sulfides, mainly including disulfides (36 %), trisulfides (32 %) and monosulfides (29 %) by gas chromatograph-mass spectrometer (GC/MS), which were estimated as the dominant antifungal factors. The observation results by transmission electron microscope (TEM) and scanning electron microscope (SEM) indicated that garlic oil could firstly penetrate into hyphae cells and even their organelles, and then destroy the cellular structure, finally leading to the leakage of both cytoplasm and macromolecules. Further proteomic analysis displayed garlic oil was able to induce a stimulated or weakened expression of some key proteins for physiological metabolism. Therefore, our study proved that garlic oil can work multiple sites of the hyphae of P. funiculosum to cause their death. The high antifungal effects of garlic oil makes it a broad application prospect in antifungal industries.

[Clinical value of MR diffusion weighted imaging in prediction of pathological complete response of rectal cancer after neoadjuvant therapy].

OBJECTIVE: To evaluate the application value of magnetic resonance diffusion-weighted imaging (DWI) combined with routine T2WI sequence in the determination of pathological complete response (pCR) after neoadjuvant therapy for rectal cancer. METHODS: Clinical data of 51 cases with locally advanced mid-low rectal cancer undergoing neoadjuvant therapy plus radical resection in the Rectal Cancer Center at The Sixth Affiliated Hospital of Sun Yat-sen University from June 2012 to April 2013 were analyzed retrospectively. Magnetic resonance DWI and T2WI sequences scanning were performed within 1 week before neoadjuvant therapy and within 1 week before operation. Routine single T2WI sequence and DWI combined with T2WI sequence were used separately to predict the residual tumor and to compare with postoperative pathological examination. The prediction values of two methods were compared. RESULTS: Of 51 patients, 12 cases had pathological complete response (pCR). Prediction of DWI combined T2WI sequence was correct in 8 cases of pCR, whose sensitivity and specificity were higher than those of routine single T2WI sequence (66.7%, 94.9% vs. 33.3%, 84.6%). Prediction value of DWI combined T2WI sequence for pCR was significantly higher as compared to routine single T2WI sequence (AUC, 0.808 vs. 0.590, P=0.001). CONCLUSION: Compared with the routine single T2WI sequence, DWI combined with T2WI sequence can improve the prediction accuracy of pathological complete response.

Antifungal effects of citronella oil against Aspergillus niger ATCC 16404.

Essential oils are aromatic oily liquids obtained from some aromatic plant materials. Certain essential oils such as citronella oil contain antifungal activity, but the antifungal effect is still unknown. In this study, we explored the antifungal effect of citronella oil with Aspergillus niger ATCC 16404. The antifungal activity of citronella oil on conidia of A. niger was determined by poisoned food technique, broth dilution method, and disc volatility method. Experimental results indicated that the citronella oil has strong antifungal activity: 0.125 (v/v) and 0.25 % (v/v) citronella oil inhibited the growth of 5 × 105 spore/ml conidia separately for 7 and 28 days while 0.5 % (v/v) citronella oil could completely kill the conidia of 5 × 105 spore/ml. Moreover, the fungicidal kinetic curves revealed that more than 90 % conidia (initial concentration is 5 × 105 spore/ml) were killed in all the treatments with 0.125 to 2 % citronella oil after 24 h. Furthermore, with increase of citronella oil concentration and treatment time, the antifungal activity was increased correspondingly. The 0.5 % (v/v) concentration of citronella oil was a threshold to kill the conidia thoroughly. The surviving conidia treated with 0.5 to 2 % citronella oil decreased by an order of magnitude every day, and no fungus survived after 10 days. With light microscope, scanning electron microscope, and transmission electron microscope, we found that citronella oil could lead to irreversible alteration of the hyphae and conidia. Based on our observation, we hypothesized that the citronella oil destroyed the cell wall of the A. niger hyphae, passed through the cell membrane, penetrated into the cytoplasm, and acted on the main organelles. Subsequently, the hyphae was collapsed and squashed due to large cytoplasm loss, and the organelles were severely destroyed. Similarly, citronella oil could lead to the rupture of hard cell wall and then act on the sporoplasm to kill the conidia. Nevertheless, the citronella oil provides a potential of being a safe and environmentally friendly fungicide in the future.

Antibacterial effect of silver nanoparticles on Staphylococcus aureus.

The antibacterial activity and mechanism of silver nanoparticles (Ag-NPs) on Staphylococcus aureus ATCC 6538P were investigated in this study. The experiment results showed the minimum bactericidal concentration (MBC) of Ag-NPs to S. aureus was 20 µg/ml. Moreover, when bacteria cells were exposed to 50 µg/ml Ag-NPs for 6 h, the cell DNA was condensed to a tension state and could have lost their replicating abilities. When S. aureus cells were exposed to 50 µg/ml Ag-NPs for 12 h, the cell wall was breakdown, resulting in the release of the cellular contents into the surrounding environments, and finally became collapsed. And Ag-NPs could reduce the enzymatic activity of respiratory chain dehydrogenase. Furthermore, the proteomic analysis showed that the expression abundance of some proteins was changed in the treated bacterial cell with Ag-NPs, formate acetyltransferase increased 5.3-fold in expression abundance, aerobic glycerol-3-phosphate dehydrogenase decreased 6.5-fold, ABC transporter ATP-binding protein decreased 6.2-fold, and recombinase A protein decreased 4.9-fold.