scholarly journals Promotion of resistance of black alder clones (Alnus glutinosa (L.) Gaertn.) against Phytophthora alni ssp. alni by cyclolipopeptide producing bacteria

2014 ◽  
Vol 63 (1-6) ◽  
pp. 222-229
Author(s):  
I. Zaspel ◽  
G. Naujoks ◽  
L. Krüger ◽  
L. H. Pham
Keyword(s):  
Disease Incidence ◽  
Combined Treatment ◽  
Alnus Glutinosa ◽  
Black Alder ◽  
Primary Roots ◽  
Comparable Effect ◽  
Root And Shoot Growth ◽  
Pathogen Control ◽  
Secondary Roots

Summary This study demonstrated the promotion of the ability of black alder clones to resist to Phytophthora alni ssp. alni with the cyclolipopeptide (CLP)-producing Pseudomonas veronii isolate PAZ1. The bacterial strain, isolated from an association with P. alni ssp. alni, and characterised by its production of the secondary metabolites viscosin and massetolides, possessed inhibitory ability against isolates of the oomycete tree pathogen in vitro. In plant experiments with alder clones in vitro, the treatment with living bacteria showed an earlier start of the rooting process and a promoted root and shoot growth. Compared to non-treated plants, the root system was improved by longer primary roots with abundant secondary roots. The treatment with a methanol extract prepared from strain PAZ1 had no comparable effect. After protective application of strain PAZ1 14 days before the pathogen, the disease incidence was lower and biomass production was higher than in the pathogen control. These results were completed by a greenhouse experiment for a period of 13 months. Bacteria application prior to the pathogen led to reduced Phytophthora incidence at two of five clones in the combined treatment.

scholarly journals Genetic Variation Explains Changes in Susceptibility in a Naïve Host Against an Invasive Forest Pathogen: The Case of Alder and the Phytophthora alni Complex

2020 ◽  
Vol 110 (2) ◽  
pp. 517-525 ◽  
Author(s):  
Miguel A. Redondo ◽  
Jan Stenlid ◽  
Jonàs Oliva
Keyword(s):  
Genetic Variation ◽  
Natural Selection ◽  
Transmission Rate ◽  
Alternative Hypothesis ◽  
Simulated Data ◽  
Alnus Glutinosa ◽  
Heritable Variation ◽  
Narrow Sense Heritability ◽  
Black Alder

Predicting whether naïve tree populations have the potential to adapt to exotic pathogens is necessary owing to the increasing rate of invasions. Adaptation may occur as a result of natural selection when heritable variation in terms of susceptibility exists in the naïve population. We searched for signs of selection on black alder (Alnus glutinosa) stands growing on riverbanks invaded by two pathogens differing in aggressiveness, namely, Phytophthora uniformis (PU) and Phytophthora × alni (PA). We compared the survival and heritability measures from 72 families originating from six invaded and uninvaded (naïve) sites by performing in vitro inoculations. The results from the inoculations were used to assess the relative contribution of host genetic variation on natural selection. We found putative signs of natural selection on alder exerted by PU but not by PA. For PU, we found a higher survival in families originating from invaded sites compared with uninvaded sites. The narrow sense heritability of susceptibility to PU of uninvaded populations was significantly higher than to PA. Simulated data supported the role of heritable genetic variation on natural selection and discarded a high aggressiveness of PA decreasing the transmission rate as an alternative hypothesis for a slow natural selection. Our findings expand on previous attempts of using heritability as a predictor for the likelihood of natural adaptation of naïve tree populations to invasive pathogens. Measures of genetic variation can be useful for risk assessment purposes or when managing Phytophthora invasions.

scholarly journals Influence of Humic Substances on Cucumber Seeds Storability and Root Rot Diseases Incidence under Salinity Conditions

2020 ◽  
pp. 51-73
Author(s):  
Ahmed Abd El-Aziz Mahmoud Awad ◽  
Hoda Mohamed Hussein Ahmed
Keyword(s):  
Humic Substances ◽  
Root Rot ◽  
Mycelial Growth ◽  
Disease Incidence ◽  
Combined Treatment ◽  
Vitro Experiment ◽  
In Vitro Experiment ◽  
Root Rot Disease ◽  
Rot Disease

Seed germination is a complex process, which is regulated by many factors including storage. The present study aims at assessing the validity of stored cucumber seeds under stressed-soil. In-vitro experiment was conducted to investigate the influence of soaking of stored cucumber (Cucumis sativus L.) seeds produced during three consequent years (2015, 2016 & 2017) in five concentrations of humic substances (HS'c) solution (0.3, 0.6, 0.9, 1.2 & 1.5%) for five different intervals (30, 90, 150, 210 & 270 min), on germination percentage (G%), germination velocity (GV) and vigor index (VI). Another In vitro experiment was conducted to assess the direct effect of HS'c on two nutritional media for Rhizoctonia solani and Fusarium solani mycelial growth, sclerotial productivity & viability, conidia viability. Greenhouse experiment was conducted to assess the effect of soaking cucumber seeds in HS'c and spraying with salicylic acid (SA) (100 and 200mg L-1) twice on growth parameters of cucumber seedlings, and controlling the root rot disease caused by R. solani and F. solani under saline conditions (2.36, 4, 5 & 6 dS m-1). The results indicate that T5 (0.3% for 210 min.) for 2015 and 2017 and T4 (0.3% for 150 min.) recorded the highest values for all studied parameters. No morphological changes were observed for the highest pathogenic two fungal isolate's mycelial growth on both fungal strains. R. solani was affected less than F. solani for the presence of different HS'c into nutrient media. 1.5% HS concentration had a reduction effect on the radical growth of fungal isolates, R. solani sclerotial production (30%) and viability (53%) and F. solani conidial viability (58%). Root rot disease was affected differently by seedling treatments of HS'c and/or SA under the four salinity conditions. The combined treatment; soaking seeds in 0.3% HS (for different period/year) and spraying seedlings with 200 SA had significantly reduced the disease incidence (DI) and disease index of both R. solani and F. solani specially in the lowest and highest salinity conditions.

scholarly journals Investigation of antiparasitic activity of ten European tree bark extracts on Toxoplasma gondii and bioguided identification of triterpenes in Alnus glutinosa barks

2021 ◽  
Author(s):  
Pierre Darme ◽  
Jérémy Spalenka ◽  
Jane Hubert ◽  
Sandie Escotte-binet ◽  
Laurent Debelle ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Alnus Glutinosa ◽  
Tree Bark ◽  
Chemotherapy Treatment ◽  
Antiparasitic Activity ◽  
Black Alder ◽  
Chemical Profiling ◽  
Maternal Fetal Transmission ◽  
Aids Chemotherapy

Toxoplasmosis is a worldwide parasitosis that affects one-third of the population. People at risk, such as immunocompromised patients (AIDS, chemotherapy treatment) or fetuses (maternal-fetal transmission) can develop severe forms of the disease. The antiparasitic activity of extracts of different polarities ( n -heptane, MeOH, MeOH/H 2 O) of ten tree species endemics to temperate regions was investigated against Toxoplasma gondii infection in vitro . Our results showed that the n -heptane extract of the black alder ( Alnus glutinosa ) exhibited a significant antiparasitic activity without any cytotoxicity at the tested concentrations, with an IC 50 of up to 25.08 μg/mL and a selectivity index higher than 3.99. The chemical profiling of this extract revealed triterpenes as major constituents. The ability of commercially available triterpene (betulin, betulinic acid, and betulone) to inhibit the growth of T. gondii was evaluated and showed growth inhibition rates of 44%, 49%, and 99% at 10 μM, respectively.

scholarly journals Aspirin enhances the therapeutic efficacy of cisplatin in oesophageal squamous cell carcinoma by inhibition of putative cancer stem cells

2021 ◽  
Author(s):  
Zhigeng Zou ◽  
Wei Zheng ◽  
Hongjun Fan ◽  
Guodong Deng ◽  
Shih-Hsin Lu ◽  
...  
Keyword(s):  
Stem Cells ◽  
Squamous Cell Carcinoma ◽  
Cancer Stem Cells ◽  
Cell Carcinoma ◽  
Cell Lines ◽  
Squamous Cell ◽  
High Throughput Sequencing ◽  
Combined Treatment ◽  
Oesophageal Squamous Cell Carcinoma

Abstract Background Cancer stem cells (CSCs) are related to the patient’s prognosis, recurrence and therapy resistance in oesophageal squamous cell carcinoma (ESCC). Although increasing evidence suggests that aspirin (acetylsalicylic acid, ASA) could lower the incidence and improve the prognosis of ESCC, the mechanism(s) remains to be fully understood. Methods We investigated the role of ASA in chemotherapy/chemoprevention in human ESCC cell lines and an N-nitrosomethylbenzylamine-induced rat ESCC carcinogenesis model. The effects of combined treatment with ASA/cisplatin on ESCC cell lines were examined in vitro and in vivo. Sphere-forming cells enriched with putative CSCs (pCSCs) were used to investigate the effect of ASA in CSCs. Assay for Transposase-Accessible Chromatin with high-throughput sequencing (ATAC-seq) was performed to determine the alterations in chromatin accessibility caused by ASA in ESCC cells. Results ASA inhibits the CSC properties and enhances cisplatin treatment in human ESCC cells. ATAC-seq indicates that ASA treatment results in remarkable epigenetic alterations on chromatin in ESCC cells, especially their pCSCs, through the modification of histone acetylation levels. The epigenetic changes activate Bim expression and promote cell death in CSCs of ESCC. Furthermore, ASA prevents the carcinogenesis of NMBzA-induced ESCC in the rat model. Conclusions ASA could be a potential chemotherapeutic adjuvant and chemopreventive drug for ESCC treatment.

scholarly journals Development of a Fluorescent Tool for Studying Legionella bozemanae Intracellular Infection

2021 ◽  
Vol 9 (2) ◽  
pp. 379
Author(s):  
Breanne M. Head ◽  
Christopher I. Graham ◽  
Teassa MacMartin ◽  
Yoav Keynan ◽  
Ann Karen C. Brassinga
Keyword(s):  
Growth Kinetics ◽  
Legionella Pneumophila ◽  
Fluorescent Protein ◽  
Disease Incidence ◽  
Acanthamoeba Castellanii ◽  
Infection Model ◽  
Intracellular Infection ◽  
Green Fluorescent

Legionnaires’ disease incidence is on the rise, with the majority of cases attributed to the intracellular pathogen, Legionella pneumophila. Nominally a parasite of protozoa, L. pneumophila can also infect alveolar macrophages when bacteria-laden aerosols enter the lungs of immunocompromised individuals. L. pneumophila pathogenesis has been well characterized; however, little is known about the >25 different Legionella spp. that can cause disease in humans. Here, we report for the first time a study demonstrating the intracellular infection of an L. bozemanae clinical isolate using approaches previously established for L. pneumophila investigations. Specifically, we report on the modification and use of a green fluorescent protein (GFP)-expressing plasmid as a tool to monitor the L. bozemanae presence in the Acanthamoeba castellanii protozoan infection model. As comparative controls, L. pneumophila strains were also transformed with the GFP-expressing plasmid. In vitro and in vivo growth kinetics of the Legionella parental and GFP-expressing strains were conducted followed by confocal microscopy. Results suggest that the metabolic burden imposed by GFP expression did not impact cell viability, as growth kinetics were similar between the GFP-expressing Legionella spp. and their parental strains. This study demonstrates that the use of a GFP-expressing plasmid can serve as a viable approach for investigating Legionella non-pneumophila spp. in real time.

scholarly journals C4b-binding protein α-chain enhances antitumor immunity by facilitating the accumulation of tumor-infiltrating lymphocytes in the tumor microenvironment in pancreatic cancer

2021 ◽  
Vol 40 (1) ◽  
Author(s):  
Kosuke Sasaki ◽  
Shigetsugu Takano ◽  
Satoshi Tomizawa ◽  
Yoji Miyahara ◽  
Katsunori Furukawa ◽  
...  
Keyword(s):  
T Cell ◽  
Tumor Microenvironment ◽  
Binding Protein ◽  
Combined Treatment ◽  
Tumor Infiltrating Lymphocytes ◽  
Pdac Cell ◽  
Α Chain ◽  
Infiltrating Lymphocytes

Abstract Background Recent studies indicate that complement plays pivotal roles in promoting or suppressing cancer progression. We have previously identified C4b-binding protein α-chain (C4BPA) as a serum biomarker for the early detection of pancreatic ductal adenocarcinoma (PDAC). However, its mechanism of action remains unclear. Here, we elucidated the functional roles of C4BPA in PDAC cells and the tumor microenvironment. Methods We assessed stromal C4BPA, the C4BPA binding partner CD40, and the number of CD8+ tumor-infiltrating lymphocytes in resected human PDAC tissues via immunohistochemical staining. The biological functions of C4BPA were investigated in peripheral blood mononuclear cells (PBMCs) and human PDAC cell lines. Mouse C4BPA (mC4BPA) peptide, which is composed of 30 amino acids from the C-terminus and binds to CD40, was designed for further in vitro and in vivo experiments. In a preclinical experiment, we assessed the efficacy of gemcitabine plus nab-paclitaxel (GnP), dual immune checkpoint blockades (ICBs), and mC4BPA peptide in a mouse orthotopic transplantation model. Results Immunohistochemical analysis revealed that high stromal C4BPA and CD40 was associated with favorable PDAC prognosis (P=0.0005). Stromal C4BPA strongly correlated with the number of CD8+ tumor-infiltrating lymphocytes (P=0.001). In in vitro experiments, flow cytometry revealed that recombinant human C4BPA (rhC4BPA) stimulation increased CD4+ and CD8+ T cell numbers in PBMCs. rhC4BPA also promoted the proliferation of CD40-expressing PDAC cells. By contrast, combined treatment with gemcitabine and rhC4BPA increased PDAC cell apoptosis rate. mC4BPA peptide increased the number of murine T lymphocytes in vitro and the number of CD8+ tumor-infiltrating lymphocytes surrounding PDAC tumors in vivo. In a preclinical study, GnP/ICBs/mC4BPA peptide treatment, but not GnP treatment, led to the accumulation of a greater number of CD8+ T cells in the periphery of PDAC tumors and to greater tumor regression than did control treatment. Conclusions These findings demonstrate that the combination of GnP therapy with C4BPA inhibits PDAC progression by promoting antitumor T cell accumulation in the tumor microenvironment.

scholarly journals Photodynamic Therapy Combined with Antibiotics or Antifungals against Microorganisms That Cause Skin and Soft Tissue Infections: A Planktonic and Biofilm Approach to Overcome Resistances

2021 ◽  
Vol 14 (7) ◽  
pp. 603
Author(s):  
Vanesa Pérez-Laguna ◽  
Isabel García-Luque ◽  
Sofía Ballesta ◽  
Antonio Rezusta ◽  
Yolanda Gilaberte
Keyword(s):  
Photodynamic Therapy ◽  
Soft Tissues ◽  
Combined Treatment ◽  
Resistance Pattern ◽  
Antimicrobial Photodynamic Therapy ◽  
Antimicrobial Drugs ◽  
Bacteria And Fungi ◽  
High Level ◽  
Selection Of

The present review covers combination approaches of antimicrobial photodynamic therapy (aPDT) plus antibiotics or antifungals to attack bacteria and fungi in vitro (both planktonic and biofilm forms) focused on those microorganisms that cause infections in skin and soft tissues. The combination can prevent failure in the fight against these microorganisms: antimicrobial drugs can increase the susceptibility of microorganisms to aPDT and prevent the possibility of regrowth of those that were not inactivated during the irradiation; meanwhile, aPDT is effective regardless of the resistance pattern of the strain and their use does not contribute to the selection of antimicrobial resistance. Additive or synergistic antimicrobial effects in vitro are evaluated and the best combinations are presented. The use of combined treatment of aPDT with antimicrobials could help overcome the difficulty of fighting high level of resistance microorganisms and, as it is a multi-target approach, it could make the selection of resistant microorganisms more difficult.

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