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Salmonella flagella confer anti-tumor immunological effect via activating Flagellin/TLR5 signalling within tumor microenvironment. Acta Pharm Sin B 2021; 11:3165-3177. [PMID: 34729307 PMCID: PMC8546927 DOI: 10.1016/j.apsb.2021.04.019] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 04/02/2021] [Accepted: 04/15/2021] [Indexed: 12/30/2022] Open
Abstract
mediated cancer therapy has achieved remarkable anti-tumor effects in experimental animal models, but the detailed mechanism remains unsolved. In this report, the active involvement of the host immune response in this process was confirmed by comparing the tumor-suppressive effects of Salmonella in immunocompetent and immunodeficient mice bearing melanoma allografts. Since flagella are key inducers of the host immune response during bacterial infection, flagella were genetically disrupted to analyse their involvement in Salmonella-mediated cancer therapy. The results showed that flagellum-deficient strains failed to induce significant anti-tumor effects, even when more bacteria were administered to offset the difference in invasion efficiency. Flagella mainly activate immune cells via Flagellin/Toll-like receptor 5 (TLR5) signalling pathway. Indeed, we showed that exogenous activation of TLR5 signalling by recombinant Flagellin and exogenous expression of TLR5 both enhanced the therapeutic efficacy of flagellum-deficient Salmonella against melanoma. Our study highlighted the therapeutic value of the interaction between Salmonella and the host immune response through Flagellin/TLR5 signalling pathway during Salmonella-mediated cancer therapy, thereby suggesting the potential application of TLR5 agonists in the cancer immune therapy.
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Key Words
- AKT, Akt serine/threonine kinase
- Bacteria-mediated cancer therapy
- CFU, colony-forming units
- CTLA-4, cytotoxic T-lymphocyte-associated protein 4
- Cancer immune therapy
- DN, dominant-negative
- ERBB2, Erb-B2 receptor tyrosine kinase 2
- ERKl, extracellular regulated protein kinase 1
- Flagellin
- Flagellum
- GAPDH, glyceraldehyde-3-phosphate dehydrogenase
- GFP, green fluorescent protein
- IFN-γ, interferon-γ
- IL, interleukins
- IκB, inhibitor of NF-κB
- JNK, c-Jun N-terminal kinase
- LPS, lipopolysaccharide
- LRR, leucine-rich repeat
- MyD88, myeloid differentiation factor 88
- NF-κB
- NF-κB, nuclear factor kappa-B
- PBS, phosphate-buffered saline
- PCR, polymerase chain reaction
- PD-1, programmed cell death protein-1
- PD-L1, programmed cell death-ligand 1
- PEI, polyethylenimine
- Salmonella
- TIR, Toll/Interleukin-1 receptor
- TLR, Toll-like receptor
- TLR5
- TME, tumor microenvironment
- TRAF6, TNF receptor associated factor 6
- VNP20009
- i.p., intraperitoneally
- i.t., intratumorally
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Novel compound FLZ alleviates rotenone-induced PD mouse model by suppressing TLR4/MyD88/NF- κB pathway through microbiota-gut-brain axis. Acta Pharm Sin B 2021; 11:2859-2879. [PMID: 34589401 PMCID: PMC8463266 DOI: 10.1016/j.apsb.2021.03.020] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 01/07/2021] [Accepted: 02/12/2021] [Indexed: 01/09/2023] Open
Abstract
Parkinson's disease (PD) is the second most common neurodegenerative disease, but none of the current treatments for PD can halt the progress of the disease due to the limited understanding of the pathogenesis. In PD development, the communication between the brain and the gastrointestinal system influenced by gut microbiota is known as microbiota-gut-brain axis. However, the explicit mechanisms of microbiota dysbiosis in PD development have not been well elucidated yet. FLZ, a novel squamosamide derivative, has been proved to be effective in many PD models and is undergoing the phase I clinical trial to treat PD in China. Moreover, our previous pharmacokinetic study revealed that gut microbiota could regulate the absorption of FLZ in vivo. The aims of our study were to assess the protective effects of FLZ treatment on PD and to further explore the underlying microbiota-related mechanisms of PD by using FLZ as a tool. In the current study, chronic oral administration of rotenone was utilized to induce a mouse model to mimic the pathological process of PD. Here we revealed that FLZ treatment alleviated gastrointestinal dysfunctions, motor symptoms, and dopaminergic neuron death in rotenone-challenged mice. 16S rRNA sequencing found that PD-related microbiota alterations induced by rotenone were reversed by FLZ treatment. Remarkably, FLZ administration attenuated intestinal inflammation and gut barrier destruction, which subsequently inhibited systemic inflammation. Eventually, FLZ treatment restored blood-brain barrier structure and suppressed neuroinflammation by inhibiting the activation of astrocytes and microglia in the substantia nigra (SN). Further mechanistic research demonstrated that FLZ treatment suppressed the TLR4/MyD88/NF-κB pathway both in the SN and colon. Collectively, FLZ treatment ameliorates microbiota dysbiosis to protect the PD model via inhibiting TLR4 pathway, which contributes to one of the underlying mechanisms beneath its neuroprotective effects. Our research also supports the importance of microbiota-gut-brain axis in PD pathogenesis, suggesting its potential role as a novel therapeutic target for PD treatment.
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Key Words
- ANOSIM, adonis and analysis of similarity
- BBB, blood–brain barrier
- CFU, colony-forming units
- CMC-Na, sodium carboxymethyl cellulose
- CNS, central nerve system
- ELISA, enzyme-linked immunosorbent assay
- FD4, FITC-dextran (MW: 4 kDa)
- FITC, fluorescein isothiocyanate
- FLZ
- GFAP, glial fibrillary acidic protein
- GI, gastrointestinal
- Gastrointestinal dysfunction
- Hp, Helicobacter pylori
- IL-1β, interleukin-1β
- IL-6, interleukin-6
- Iba-1, ionized calcium-binding adapter molecule 1
- KEGG, Kyoto Encyclopedia of Genes and Genomes
- LBP, lipopolysaccharide binding protein
- LDA, linear discriminant analysis
- LPS, lipopolysaccharide
- MLNs, mesenteric lymph nodes
- Microbiota–gut–brain axis
- Neuroinflammation
- OTU, operational taxonomic unit
- PBS, phosphate-buffered saline
- PCoA, principal coordinate analysis
- PD, Parkinson's disease
- Parkinson's disease
- Rotenone mouse model
- SD, standard deviation
- SN, substantia nigra
- Systemic inflammation
- TEM, transmission electron microscopy
- TH, tyrosine hydroxylase
- TLR4, toll-like receptor 4
- TLR4/MyD88/NF-κB pathway
- TNF-α, tumor necrosis factor-α
- qPCR, quantitative polymerase chain reaction assay
- α-Syn, α-synuclein
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Abstract
BACKGROUND Multiple infection outbreaks have been linked to contaminated duodenoscopes worldwide. However, the contamination rate of patient-ready duodenoscopes varies highly amongst published studies testing this subject. We aimed to estimate the contamination rate of reprocessed patient-ready duodenoscopes for endoscopic retrograde cholangio-pancreatography (ERCP) based on currently available data. METHODS We searched the PubMed and Embase databases from January 1, 2010 until March 10, 2020, for citations investigating contamination rates of reprocessed patient-ready duodenoscopes. Studies not assessing other types of endoscopes than duodenoscopes were excluded from the analysis. Study eligibility and data extraction was evaluated by three reviewers independently. A random-effects model (REM) based on the proportion distribution was used to calculate the pooled total contamination rate of reprocessed patient-ready duodenoscopes. Subgroup analyses were carried out to assess contamination rates when using different reprocessing methods by comparing single high-level disinfection (HLD) with double HLD and ethylene oxide (EtO) gas sterilization. Additionally, we investigated the contamination rate between studies conducted following an outbreak compared to non-outbreak-initiated studies. FINDINGS We identified 15 studies that fulfilled the inclusion, which included 925 contaminated duodenoscopes from 13,112 samples. The calculated total weighted contamination rate was 15.25% ± 0.018 (95% confidence interval [Cl]: 11.74% - 18.75%). The contamination rate after only using HLD was 16.14% ± 0.019 (95% Cl: 12.43% - 19.85%) and after using either dHLD or EtO the contamination rate decreased to 9.20% ± 0.025 (95% Cl: 4.30% - 14.10%). Studies conducted following an outbreak (n=4) showed a 5.72% ± 0.034 (95% Cl: 0.00% - 12.43%) contamination rate, and non-outbreak-initiated studies (n=11) revealed a contamination rate of 21.50% ± 0.031 (95% Cl: 15.35% - 27.64%). INTERPRETATION This is the first meta-analysis to estimate the contamination rate of patient-ready duodenoscopes used for ERCP. Based on the available literature, our analysis demonstrates that there is a 15.25% contamination rate of reprocessed patient-ready duodenoscopes. Additionally, the analysis indicates that dHLD and EtO reprocessing methods are superior to single HLD but still not efficient in regards to cleaning the duodenoscopes properly. Furthermore, studies conducted following an outbreak did not entail a higher contamination rate compared to non-outbreak-initiated studies. FUNDING The authors received no financial support for the research, authorship, and/or publication of this article.
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Key Words
- AGA, American Gastroenterological Association
- AORN, The Joint Commission and The Association of Perioperative Registered Nurses
- Bacterial*
- CDC, Center for Disease Control and Prevention
- CFU, colony-forming units
- CRE, carbapenem-resistant Enterobacteriaceae
- Cl, confidence interval
- Cross infection
- Drug Resistance
- Duodenoscopes
- ERCI, Environmental Risk Communications, Inc.
- ERCP, endoscopic retrograde cholangio-pancreatography
- Equipment contamination
- EtO, ethylene oxide
- FDA, Food & Drug Administration
- HLD, high-level disinfection
- Infection Control
- MDR, multi-drug-resistant
- MeSH, medical subject headings
- Multiple
- PRISMA, Preferred Reporting Items for Systematic Reviews and Meta-Analyses
- REM, random-effects model
- dHLD, double high-level disinfection
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Coinoculation of soybean plants with Bradyrhizobium japonicum and Trichoderma harzianum: Coexistence of both microbes and relief of nitrate inhibition of nodulation. ACTA ACUST UNITED AC 2020; 26:e00461. [PMID: 32420051 PMCID: PMC7218258 DOI: 10.1016/j.btre.2020.e00461] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 04/15/2020] [Accepted: 04/22/2020] [Indexed: 12/18/2022]
Abstract
Bradyrhizobium japonicum and Trichoderma harzianum coexisted in soybean rhizosphere. Soybean inoculated with both microbes nodulated with high nitrate concentrations. T. harzianum produced auxins in culture medium. Auxins applied with B. japonicum alone relieved nitrate inhibition of nodulation.
Coinoculation of plants with mixtures of beneficial microbes sometimes produces synergistic effects. In this study, the effect of soybean coinoculation with the N2-fixing Bradyrhizobium japonicum E109 and the biocontrol fungus Trichoderma harzianum Th5cc was analyzed. Nodulation by E109 was not hampered by Th5cc, which antagonized five out of seven soybean pathogens tested. Furthermore, Th5cc relieved nitrate-inhibition of nodulation, enabling the formation of nodules containing infected cells with bacteroids in the presence of the otherwise inhibitory 10 mM KNO3. Th5cc released micromolar amounts of auxin, and addition of 11 μM indoleacetic acid to soybean plants inoculated with E109 in the absence of Th5cc also induced nodulation in the presence of 10 mM KNO3. Thus, Th5cc may release auxins into the soybean rhizosphere, which hormones might participate in overcoming the nitrate-inhibition of nodulation. Our results suggest that soybean plants coinoculated with these microorganisms might benefit from biocontrol while contributing to soil-nitrogen preservation.
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Key Words
- AG, arabinose-gluconate medium
- Bradyrhizobium
- CFU, colony-forming units
- CR, Congo Red
- Coinoculation
- DAI, days after inoculation
- IAA, indoleacetic acid
- LPCB, lactophenol cotton blue
- MFS, modified Fåhræus solution
- Nitrate
- PDA, potato-dextrose agar
- PGPM, plant-growth promoting microbe
- Soybean
- Trichoderma
- YM, yeast-extract mannitol medium
- YMA, YM with 1.5 % (w/v) agar
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Probiotics modulate the microbiota-gut-brain axis and improve memory deficits in aged SAMP8 mice. Acta Pharm Sin B 2020; 10:475-487. [PMID: 32140393 PMCID: PMC7049608 DOI: 10.1016/j.apsb.2019.07.001] [Citation(s) in RCA: 178] [Impact Index Per Article: 44.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2019] [Revised: 05/08/2019] [Accepted: 05/15/2019] [Indexed: 12/12/2022] Open
Abstract
ProBiotic-4 is a probiotic preparation composed of Bifidobacterium lactis, Lactobacillus casei, Bifidobacterium bifidum, and Lactobacillus acidophilus. This study aims to investigate the effects of ProBiotic-4 on the microbiota–gut–brain axis and cognitive deficits, and to explore the underlying molecular mechanism using senescence-accelerated mouse prone 8 (SAMP8) mice. ProBiotic-4 was orally administered to 9-month-old SAMP8 mice for 12 weeks. We observed that ProBiotic-4 significantly improved the memory deficits, cerebral neuronal and synaptic injuries, glial activation, and microbiota composition in the feces and brains of aged SAMP8 mice. ProBiotic-4 substantially attenuated aging-related disruption of the intestinal barrier and blood–brain barrier, decreased interleukin-6 and tumor necrosis factor-α at both mRNA and protein levels, reduced plasma and cerebral lipopolysaccharide (LPS) concentration, toll-like receptor 4 (TLR4) expression, and nuclear factor-κB (NF-κB) nuclear translocation in the brain. In addition, not only did ProBiotic-4 significantly decreased the levels of γ-H2AX, 8-hydroxydesoxyguanosine, and retinoic-acid-inducible gene-I (RIG-I), it also abrogated RIG-I multimerization in the brain. These findings suggest that targeting gut microbiota with probiotics may have a therapeutic potential for the deficits of the microbiota–gut–brain axis and cognitive function in aging, and that its mechanism is associated with inhibition of both TLR4-and RIG-I-mediated NF-κB signaling pathway and inflammatory responses.
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Key Words
- 8-OHdG, 8-hydroxydesoxyguanosine
- AAMI, age-associated memory impairment
- AD, Alzheimer's disease
- BBB, blood–brain barrier
- CFU, colony-forming units
- Cognitive decline
- ELISA, enzyme-linked immunosorbent assay
- F/B, Firmicutes/Bacteroidetes
- GFAP, glial fibrillary acidic protein
- HE, hematoxylin and eosin
- IHC, immunohistochemistry
- IL-6, interleukin-6
- Iba-1, ionized calcium binding adaptor molecule-1
- LPS, lipopolysaccharide
- MCI, mild cognitive impairment
- Microbiota–gut–brain axis
- NF-κB
- NF-κB, nuclear factor-κB
- NMDS, non-metric multidimensional scaling
- OTU, operational taxonomic unit
- PAMP, pathogen-associated molecular pattern
- Probiotics
- RIG-I
- RIG-I, retinoic-acid-inducible gene-I
- SAMP8 mice
- SAMP8, senescence-accelerated mouse prone 8
- SYN, synaptophysin
- TEM, transmission electron microscopy
- TLR4
- TLR4, toll-like receptor 4
- TNF-α, tumor necrosis factor-α
- VE-cadherin, vascular endothelial-cadherin
- ZO-1, zona occluden-1
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Variations in the C-unit of bedaquiline provides analogues with improved biology and pharmacology. Bioorg Med Chem 2019; 28:115213. [PMID: 31810890 DOI: 10.1016/j.bmc.2019.115213] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 11/06/2019] [Accepted: 11/10/2019] [Indexed: 11/25/2022]
Abstract
Analogues of the anti-tuberculosis drug bedaquiline, bearing a 3,5-dimethoxy-4-pyridyl C-unit, retain high anti-bacterial potency yet exert less inhibition of the hERG potassium channel, in vitro, than the parent compound. Two of these analogues (TBAJ-587 and TBAJ-876) are now in preclinical development. The present study further explores structure-activity relationships across a range of related 3,5-disubstituted-4-pyridyl C-unit bedaquiline analogues of greatly varying lipophilicity (clogP from 8.16 to 1.89). This broader class shows similar properties to the 3,5-dimethoxy-4-pyridyl series, being substantially more potent in vitro and equally active in an in vivo (mouse) model than bedaquiline, while retaining a lower cardiovascular risk profile through greatly attenuated hERG inhibition.
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Key Words
- CFU, colony-forming units
- HPLC, high-peformance liquid chromatography
- LDA, lithium diisopropylamide
- LORA, low oxygen recovery assay
- LiTMP, lithium tetramethylpiperidide
- M.tb, Mycobacterium tuberculosis
- MABA, microplate alamar blue assay
- MIC(90), minimum concentration for 90% inhibition
- TB, tuberculosis
- hERG, the alpha subunit of a K+ channel that contributes to the electrical activity of the heart
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Effect of inactivated Streptococcus pneumoniae as non-pathogenic particles on the severity of pneumonia caused by respiratory syncytial virus infection in mice. Toxicol Rep 2019; 6:514-520. [PMID: 31245279 PMCID: PMC6581880 DOI: 10.1016/j.toxrep.2019.05.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 04/26/2019] [Accepted: 05/05/2019] [Indexed: 11/29/2022] Open
Abstract
We made inactivated Streptococcus pneumoniae (ISP) as non-pathogenic particles. We evaluated effects of ISP on development of pneumonia by RSV infection in mice. ISP didn’t show histopathological effects on lungs of RSV-infected mice. ISP reduced virus titer and infiltration of lymphocyte in the lungs. The inherent activity of ISP as particles in RSV infection is discussed.
The severity of pneumonia in respiratory syncytial virus (RSV) infection is strongly related to host immune response and external factors such as bacteria and environmental chemicals. We investigated the effect of inactivated Streptococcus pneumoniae (ISP) as non-pathogenic particles on the severity of pneumonia in RSV-infected mice. Mice were intranasally exposed to ISP before RSV infection. On day 5 post-infection, we examined tissues, virus titer, and infiltrated cells in the lungs. The ISP did not cause significant histopathological effects in the lungs of RSV infected mice, but reduced virus titer. It also reduced the ratio of lymphocyte infiltration into the lungs and consequently the ratio of macrophage increased. In addition, we found that ISP increased RANTES level in bronchoalveolar lavage fluid from RSV-infected mice on day 1 post-infection, but reduced type I interferon levels. Thus, ISP did not exacerbate pneumonia in RSV infection, rather, it might mildly reduce the severity. We characterize and discuss the inherent activity of ISP as non-pathogenic particles inducing the role of RANTES on the pneumonia in RSV infection.
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Key Words
- BALF, bronchoalveolar lavage fluids
- CFU, colony-forming units
- ELISA, enzyme-linked immunosorbent assay
- IFN, interferon
- ISP, inactivated S. pneumoniae
- Infiltrated cells
- Non-pathogenic pneumococcal particles
- PBS, phosphate-buffered saline
- PFU, plaque-forming units
- Pneumonia
- RSV
- RSV, respiratory syncytial virus
- S. pneumoniae, Streptococcus pneumoniae
- Streptococcus pneumonia
- TiO2, titanium dioxide
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3,5-Dialkoxypyridine analogues of bedaquiline are potent antituberculosis agents with minimal inhibition of the hERG channel. Bioorg Med Chem 2019; 27:1292-1307. [PMID: 30803745 PMCID: PMC6467547 DOI: 10.1016/j.bmc.2019.02.026] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 02/06/2019] [Accepted: 02/14/2019] [Indexed: 11/27/2022]
Abstract
Bedaquiline is a new drug of the diarylquinoline class that has proven to be clinically effective against drug-resistant tuberculosis, but has a cardiac liability (prolongation of the QT interval) due to its potent inhibition of the cardiac potassium channel protein hERG. Bedaquiline is highly lipophilic and has an extremely long terminal half-life, so has the potential for more-than-desired accumulation in tissues during the relatively long treatment durations required to cure TB. The present work is part of a program that seeks to identify a diarylquinoline that is as potent as bedaquiline against Mycobacterium tuberculosis, with lower lipophilicity, higher clearance, and lower risk for QT prolongation. Previous work led to the identification of compounds with greatly-reduced lipophilicity compounds that retain good anti-tubercular activity in vitro and in mouse models of TB, but has not addressed the hERG blockade. We now present compounds where the C-unit naphthalene is replaced by a 3,5-dialkoxy-4-pyridyl, demonstrate more potent in vitro and in vivo anti-tubercular activity, with greatly attenuated hERG blockade. Two examples of this series are in preclinical development.
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Key Words
- CFU, colony-forming units
- HPLC, high-performance liquid chromatography
- LDA, lithium diisopropylamide
- LORA, low oxygen recovery assay
- LiTMP, lithium tetramethylpiperidide
- M. tb, mycobacterium tuberculosis
- MABA, microplate alamar blue assay
- MDR, multidrug-resistant
- MIC90, minimum concentration for 90% inhibition of growth
- TB, tuberculosis
- hERG (human Ether-a-go-go Related Gene)
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Effects of a new combination of plant extracts plus d-mannose for the management of uncomplicated recurrent urinary tract infections. J Chemother 2017; 30:107-114. [PMID: 29078739 DOI: 10.1080/1120009x.2017.1393587] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Urinary tract infections (UTIs) are an economic burden for public health. The increasing prevalence of resistant bacteria which cause UTIs may be related to the inappropriate prescription of antibiotics. The aim of this preliminary study was to evaluate whether three different combinations of plant extracts plus d-mannose are effective in preventing the recurrence of UTIs. Three groups of patients received three combinations of plant extracts in conjunction with d-mannose. These were: berberine, arbutin and birch (group A); berberine, arbutin, birch and forskolin (group B); and proanthocyanidins (group C). The clinical recurrence of cystitis at the end of treatment and during follow-up was determined by comparison with baseline measurements using the microbiological assessment of urine samples, vaginal swabs and vaginal smear slides. Patients in groups A and B had a lower incidence of episodes of recurrent cystitis during treatment and follow-up, samples with a significantly lower median bacterial load and a reduction of the grade of lactobacillary flora compared to patients in group C.
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Evaluation of the efficiency and utility of recombinant enzyme-free seamless DNA cloning methods. Biochem Biophys Rep 2017; 9:310-315. [PMID: 28956018 PMCID: PMC5614619 DOI: 10.1016/j.bbrep.2017.01.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2016] [Revised: 11/07/2016] [Accepted: 01/25/2017] [Indexed: 11/24/2022] Open
Abstract
Simple and low-cost recombinant enzyme-free seamless DNA cloning methods have recently become available. In vivo Escherichia coli cloning (iVEC) can directly transform a mixture of insert and vector DNA fragments into E. coli, which are ligated by endogenous homologous recombination activity in the cells. Seamless ligation cloning extract (SLiCE) cloning uses the endogenous recombination activity of E. coli cellular extracts in vitro to ligate insert and vector DNA fragments. An evaluation of the efficiency and utility of these methods is important in deciding the adoption of a seamless cloning method as a useful tool. In this study, both seamless cloning methods incorporated inserting DNA fragments into linearized DNA vectors through short (15-39 bp) end homology regions. However, colony formation was 30-60-fold higher with SLiCE cloning in end homology regions between 15 and 29 bp than with the iVEC method using DH5α competent cells. E. coli AQ3625 strains, which harbor a sbcA gene mutation that activates the RecE homologous recombination pathway, can be used to efficiently ligate insert and vector DNA fragments with short-end homology regions in vivo. Using AQ3625 competent cells in the iVEC method improved the rate of colony formation, but the efficiency and accuracy of SLiCE cloning were still higher. In addition, the efficiency of seamless cloning methods depends on the intrinsic competency of E. coli cells. The competency of chemically competent AQ3625 cells was lower than that of competent DH5α cells, in all cases of chemically competent cell preparations using the three different methods. Moreover, SLiCE cloning permits the use of both homemade and commercially available competent cells because it can use general E. coli recA- strains such as DH5α as host cells for transformation. Therefore, between the two methods, SLiCE cloning provides both higher efficiency and better utility than the iVEC method for seamless DNA plasmid engineering.
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Vaccines for viral and bacterial pathogens causing acute gastroenteritis: Part II: Vaccines for Shigella, Salmonella, enterotoxigenic E. coli (ETEC) enterohemorragic E. coli (EHEC) and Campylobacter jejuni. Hum Vaccin Immunother 2015; 11:601-19. [PMID: 25715096 DOI: 10.1080/21645515.2015.1011578] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
In Part II we discuss the following bacterial pathogens: Shigella, Salmonella (non-typhoidal), diarrheogenic E. coli (enterotoxigenic and enterohemorragic) and Campylobacter jejuni. In contrast to the enteric viruses and Vibrio cholerae discussed in Part I of this series, for the bacterial pathogens described here there is only one licensed vaccine, developed primarily for Vibrio cholerae and which provides moderate protection against enterotoxigenic E. coli (ETEC) (Dukoral(®)), as well as a few additional candidates in advanced stages of development for ETEC and one candidate for Shigella spp. Numerous vaccine candidates in earlier stages of development are discussed.
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Key Words
- CFU, colony-forming units
- CFs, colonization factors
- CT, cholera toxin
- CT-B cholera toxin B subunit
- Campylobacter
- CtdB, cytolethal distending toxin subunit B
- E. coli
- EHEC
- EPEC, enteropathogenic E. coli
- ETEC
- ETEC, enterotoxigenic E. coli
- GEMS, Global enterics multicenter study
- HUS, hemolytic uremic syndrome
- IM, intramuscular
- IgA, immunoglobulin A
- IgG, immunoglobulin G
- IgM, immunoglobulin M
- LEE, locus of enterocyte effacement
- LPS, lipopolysaccharide
- LT, heat labile toxin
- LT-B
- OMV, outer membrane vesicles
- ST, heat stable toxin
- STEC
- STEC, shigatoxin producing E. coli
- STh, human heat stable toxin
- STp, porcine heat stable toxin
- Salmonella
- Shigella
- Stx, shigatoxin
- TTSS, type III secretion system
- V. cholera
- WHO, World Health Organization
- acute diarrhea
- dmLT, double mutant heat labile toxin
- enteric pathogens
- enterohemorrhagic E. coli
- gastroenteritis
- heat labile toxin B subunit
- norovirus
- rEPA, recombinant exoprotein A of Pseudomonas aeruginosa
- rotavirus
- vaccines
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Comparison of virulence between the Yersinia pestis Microtus 201, an avirulent strain to humans, and the vaccine strain EV in rhesus macaques, Macaca mulatta. Hum Vaccin Immunother 2015; 10:3552-60. [PMID: 25483697 DOI: 10.4161/hv.35119] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Our previous study has demonstrated that Yersinia pestis Microtus 201 is a low virulent strain to the Chinese-origin rhesus macaques, Macaca mulatta, and can protect it against high dose of virulent Y. pestis challenge by subcutaneous route. To investigate whether the Y. pestis Microtus 201 can be used as a live attenuated vaccine candidate, in this study its intravenous virulence was determined and compared with the live attenuated vaccine strain EV in the Chinese-origin rhesus macaque model. The results showed that the Chinese-origin rhesus macaques can survive intravenous infection with approximately 10(9) CFU of the Y. pestis Microtus 201, but all the animals succumbed to 10(10) CFU of intravenous infection. By contrast, all the animals survive intravenous infection with 10(10) CFU of the vaccine EV. Post-mortem examination showed multiple areas of severe abscess in the lungs of the dead animals infected with 10(10) CFU of the Y. pestis Microtus 201, whereas histopathology observation, microbiological examination and immunohistochemistry staining showed that the Y. pestis Microtus 201 also invaded hearts, livers, spleens, kidneys and lymph nodes and caused different degrees of pathological changes in these organs. These results indicated that the Y. pestis Microtus 201 is indeed low virulent to monkeys, but it is more virulent than the vaccine EV when administered by intravenous route. The Y. pestis Microtus 201 mainly attack the lungs when administered by intravenous infection, which may be the leading cause of animal death.
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A simple and ultra-low cost homemade seamless ligation cloning extract (SLiCE) as an alternative to a commercially available seamless DNA cloning kit. Biochem Biophys Rep 2015; 4:148-151. [PMID: 29124198 PMCID: PMC5668909 DOI: 10.1016/j.bbrep.2015.09.005] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Revised: 09/08/2015] [Accepted: 09/09/2015] [Indexed: 11/27/2022] Open
Abstract
The seamless ligation cloning extract (SLiCE) method is a novel seamless DNA cloning tool that utilizes homologous recombination activities in Escherichia coli cell lysates to assemble DNA fragments into a vector. Several laboratory E. coli strains can be used as a source for the SLiCE extract; therefore, the SLiCE-method is highly cost-effective.The SLiCE has sufficient cloning ability to support conventional DNA cloning, and can simultaneously incorporate two unpurified DNA fragments into vector. Recently, many seamless DNA cloning kits have become commercially available; these are generally very convenient, but expensive. In this study, we evaluated the cloning efficiencies between a simple and highly cost-effective SLiCE-method and a commercial kit under various molar ratios of insert DNA fragments to vector DNA. This assessment identified that the SLiCE from a laboratory E. coli strain yielded 30−85% of the colony formation rate of a commercially available seamless DNA cloning kit. The cloning efficiencies of both methods were highly effective, exhibiting over 80% success rate under all conditions examined. These results suggest that SLiCE from a laboratory E. coli strain can efficiently function as an effective alternative to commercially available seamless DNA cloning kits.
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IL-1 signaling inhibits Trichophyton rubrum conidia development and modulates the IL-17 response in vivo. Virulence 2015; 6:449-57. [PMID: 25950847 DOI: 10.1080/21505594.2015.1020274] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Dermatophytosis are one of the most common fungal infections in the world. They compromise keratinized tissues and the main etiological agent is Trichophyton rubrum. Macrophages are key cells in innate immunity and prominent sources of IL-1β, a potent inflammatory cytokine whose main production pathway is by the activation of inflammasomes and caspase-1. However, the role of inflammasomes and IL-1 signaling against T.rubrum has not been reported. In this work, we observed that bone marrow-derived macrophages produce IL-1β in response to T.rubrum conidia in a NLRP3-, ASC- and caspase-1-dependent fashion. Curiously, lack of IL-1 signaling promoted hyphae development, uncovering a protective role for IL-1β in macrophages. In addition, mice lacking IL-1R showed reduced IL-17 production, a key cytokine in the antifungal defense, in response to T.rubrum. Our findings point to a prominent role of IL-1 signaling in the immune response to T.rubrum, opening the venue for the study of this pathway in other fungal infections.
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