scholarly journals Differential effects of antibiotics on neutrophils exposed to lipoteichoic acid derived from Staphylococcus aureus

2020 ◽  
Vol 19 (1) ◽  
Author(s):  
Marquerita Algorri ◽  
Annie Wong-Beringer
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Agents ◽  
Lipoteichoic Acid ◽  
Neutrophil Function ◽  
Exposure Level ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Persistent Bacteremia ◽  
Neutrophil Survival

Abstract Background Persistent bacteremia occurs in at least 30% of patients with Staphylococcus aureus bloodstream infection (SAB) and may be attributable to a dysregulated host immune response. Neutrophils interact with a variety of S. aureus microbial factors, including lipoteichoic acid (LTA), to activate phagocytic function in a concentration-dependent manner. Antibiotics have been shown to exert both direct antimicrobial action as well as immunomodulatory effects. In this study, we compared the effects of different anti-staphylococcal antibiotics on LTA-mediated immune activation of neutrophils. Methods Neutrophils obtained from healthy volunteers were exposed to two levels of LTA (1 and 10 μg/ml) with or without addition of antibiotics from different pharmacologic classes (vancomycin, daptomycin, ceftaroline). Neutrophil function was assessed by examining phagocytic response, activation (CD11b, CD62L expression), Toll-like receptor-2 expression, cell survival and apoptosis, and CXCL8 release. Results Differential LTA-mediated antibiotic effects on neutrophil function were observed primarily at the high LTA exposure level. Ceftaroline in the presence of 10 μg/ml LTA had the most prominent effects on phagocytosis and CD11b and CD62L expression, with trends towards increased neutrophil survival and preservation of CXCL8 release when compared to daptomycin and vancomycin with the latter significantly dampening PMN CXCL8 release. Conclusions Select antimicrobial agents, such as ceftaroline, exert immunostimulatory effects on neutrophils exposed to S. aureus LTA, which when confirmed in vivo, could be leveraged for its dual immunomodulatory and antibacterial actions for the treatment of persistent SAB mediated by a dysregulated host response.

scholarly journals Antibacterial Activity and Mode of Action of Lactoquinomycin A from Streptomyces bacillaris

Marine Drugs ◽  
2020 ◽  
Vol 19 (1) ◽  
pp. 7
Author(s):  
Beomkoo Chung ◽  
Oh-Seok Kwon ◽  
Jongheon Shin ◽  
Ki-Bong Oh
Keyword(s):  
Staphylococcus Aureus ◽  
Dna Damage ◽  
Inhibitory Activity ◽  
Mode Of Action ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Dependent Manner ◽  
Mobility Shift ◽  
Concentration Dependent Manner ◽  
Methicillin Resistant

This study aims to isolate and identify the structure of antibacterial compounds having potent activity on methicillin-resistant Staphylococcus aureus (MRSA) from marine actinomycetes, and also to identify their mode of action. Lactoquinomycin A (LQM-A) (compound 1) and its derivatives (2–4) were isolated from marine-derived Streptomyces bacillaris strain MBTC38, and their structures were determined using extensive spectroscopic methods. These compounds showed potent antibacterial activities against Gram-positive bacteria, with MIC values of 0.06–4 μg/mL. However, the tested compounds exhibited weak inhibitory activity against Gram-negative bacteria, although they were effective against Salmonella enterica (MIC = 0.03–1 μg/mL). LQM-A exhibited the most significant inhibitory activity against methicillin-resistant Staphylococcus aureus (MRSA) (MIC = 0.25–0.5 μg/mL), with a low incidence of resistance. An in vivo dual-reporter assay designed to distinguish between compounds that inhibit translation and those that induce DNA damage was employed to assess the mode of action of LQM-A. LQM-A-induced DNA damage and did not inhibit protein synthesis. The gel mobility shift assay showed that LQM-A switched plasmid DNA from the supercoiled to relaxed form in a time- and concentration-dependent manner. These data suggest that LQM-A intercalated into double-stranded DNA and damaged DNA repair.

scholarly journals Identification and Characterization of SirA, an Iron-Regulated Protein from Staphylococcus aureus

1999 ◽  
Vol 181 (5) ◽  
pp. 1436-1443 ◽  
Author(s):  
Jon H. Heinrichs ◽  
LaVette E. Gatlin ◽  
Charles Kunsch ◽  
Gil H. Choi ◽  
Mark S. Hanson
Keyword(s):  
Staphylococcus Aureus ◽  
Pathogenic Bacteria ◽  
Antimicrobial Agents ◽  
Genomic Sequence ◽  
Iron Acquisition ◽  
Bacterial Species ◽  
Dependent Manner ◽  
Dyad Symmetry ◽  
Siderophore Transport

ABSTRACT The acquisition of iron by pathogenic bacteria is often a crucial step in establishing infection. To accomplish this, many bacteria, including Staphylococcus aureus, produce low-molecular-weight iron-chelating siderophores. However, the secretion and transport of these molecules in gram-positive organisms are poorly understood. The sequence, organization, and regulation of genes involved in siderophore transport are conserved among gram-negative bacteria. We used this information to identify a putative siderophore transport locus from an S. aureus genomic sequence database. This locus contains three predicted open reading frames with a high degree of homology to genes involved in siderophore uptake in several bacterial species, in particular the cbrlocus of the plant pathogen Erwinia chrysanthemi. The first gene in the locus, which we have designated sir for staphylococcal iron regulated, encodes a putative lipoprotein with a molecular mass of 37 kDa. The open reading frame is preceded by a 19-bp region of dyad symmetry with homology for operator sequences controlling iron-regulated expression of genes in other bacteria. Fur titration experiments indicate that this region of dyad symmetry is sufficient for Fur-dependent regulation in Escherichia coli. The expression of this gene was repressed, in a dose-dependent manner, by the addition of iron to the S. aureus culture medium. sir-encoded proteins may be involved in iron acquisition in vivo and therefore may be targets for antimicrobial agents.

Chickpea (Cicer arietinum L.) Lectin Exhibit Inhibition of ACE-I, α-amylase and α-glucosidase Activity

2019 ◽  
Vol 26 (7) ◽  
pp. 494-501 ◽  
Author(s):  
Sameer Suresh Bhagyawant ◽  
Dakshita Tanaji Narvekar ◽  
Neha Gupta ◽  
Amita Bhadkaria ◽  
Ajay Kumar Gautam ◽  
...  
Keyword(s):  
Biological Effects ◽  
Exchange Chromatography ◽  
Health Concern ◽  
Carbohydrate Binding ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Ic50 Values ◽  
Chickpea Lectin

Background: Diabetes and hypertension are the major health concern and alleged to be of epidemic proportions. This has made it a numero uno subject at various levels of investigation. Glucosidase inhibitor provides the reasonable option in treatment of Diabetes Mellitus (DM) as it specifically targets post prandial hyperglycemia. The Angiotensin Converting Enzyme (ACE) plays an important role in hypertension. Therefore, inhibition of ACE in treatment of elevated blood pressure attracts special interest of the scientific community. Chickpea is a food legume and seeds contain carbohydrate binding protein- a lectin. Some of the biological properties of this lectin hitherto been elucidated. Methods: Purified by ion exchange chromatography, chickpea lectin was tested for its in vitro antioxidant, ACE-I inhibitory and anti-diabetic characteristic. Results: Lectin shows a characteristic improvement over the synthetic drugs like acarbose (oral anti-diabetic drug) and captopril (standard antihypertensive drug) when, their IC50 values are compared. Lectin significantly inhibited α-glucosidase and α-amylase in a concentration dependent manner with IC50 values of 85.41 ± 1.21 ҝg/ml and 65.05 ± 1.2 µg/ml compared to acarbose having IC50 70.20 ± 0.47 value of µg/ml and 50.52 ± 1.01 µg/ml respectively. β-Carotene bleaching assay showed antioxidant activity of lectin (72.3%) to be as active as Butylated Hydroxylanisole (BHA). In addition, lectin demonstrated inhibition against ACE-I with IC50 value of 57.43 ± 1.20 µg/ml compared to captopril. Conclusion: Lectin demonstrated its antioxidant character, ACE-I inhibition and significantly inhibitory for α-glucosidase and α-amylase seems to qualify as an anti-hyperglycemic therapeutic molecule. The biological effects of chickpea lectin display potential for reducing the parameters of medically debilitating conditions. These characteristics however needs to be established under in vivo systems too viz. animals through to humans.

scholarly journals Modulatory Effects of Osthole on Lipopolysaccharides-Induced Inflammation in Caco-2 Cell Monolayer and Co-Cultures with THP-1 and THP-1-Derived Macrophages

Nutrients ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 123
Author(s):  
Natalia K. Kordulewska ◽  
Justyna Topa ◽  
Małgorzata Tańska ◽  
Anna Cieślińska ◽  
Ewa Fiedorowicz ◽  
...  
Keyword(s):  
Gene Expression ◽  
Inflammatory Reaction ◽  
Wide Spectrum ◽  
Cell Monolayer ◽  
In Vivo Studies ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Tnf Α

Lipopolysaccharydes (LPS) are responsible for the intestinal inflammatory reaction, as they may disrupt tight junctions and induce cytokines (CKs) secretion. Osthole has a wide spectrum of pharmacological effects, thus its anti-inflammatory potential in the LPS-treated Caco-2 cell line as well as in Caco-2/THP-1 and Caco-2/macrophages co-cultures was investigated. In brief, Caco-2 cells and co-cultures were incubated with LPS to induce an inflammatory reaction, after which osthole (150–450 ng/mL) was applied to reduce this effect. After 24 h, the level of secreted CKs and changes in gene expression were examined. LPS significantly increased the levels of IL-1β, -6, -8, and TNF-α, while osthole reduced this effect in a concentration-dependent manner, with the most significant decrease when a 450 ng/mL dose was applied (p < 0.0001). A similar trend was observed in changes in gene expression, with the significant osthole efficiency at a concentration of 450 ng/μL for IL1R1 and COX-2 (p < 0.01) and 300 ng/μL for NF-κB (p < 0.001). Osthole increased Caco-2 monolayer permeability, thus if it would ever be considered as a potential drug for minimizing intestinal inflammatory symptoms, its safety should be confirmed in extended in vitro and in vivo studies.

scholarly journals The Antiinfective Effects of Velvet Antler of Formosan Sambar Deer (Cervus unicolor swinhoei) onStaphylococcus aureus-Infected Mice

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Ting-Yeu Dai ◽  
Chih-Hua Wang ◽  
Kun-Nan Chen ◽  
I-Nung Huang ◽  
Wei-Sheng Hong ◽  
...  
Keyword(s):  
Lipoteichoic Acid ◽  
Lavage Fluid ◽  
Dependent Manner ◽  
Protective Mechanisms ◽  
Velvet Antler ◽  
Sambar Deer ◽  
Dose Dependent ◽  
Cervus Unicolor

We assayed the effects of velvet antler (VA) of Formosan sambar deer (Cervus unicolor swinhoei) and its extracts on the anti-infective activity against pathogenicStaphylococcus aureus in vitroandin vivoin this study.In vitrodata indicated that the VA extracts stimulated the proliferation of resting splenocytes and macrophages in a dose-dependent manner up to the highest concentration used (150 μg mL−1). The production of proinflammatory cytokines (TNF-α, IL-6, IL-12) by lipoteichoic acid was significantly suppressed after being cocultured with the VA extracts in a dose-dependent manner. Animal test inS. aureus-infected mice demonstrated that the numbers of bacteria determined in the kidneys and peritoneal lavage fluid ofS. aureus-infected mice were significantly higher than those found in the same organs of mice pretreated with the VA samples. Moreover, the highly enhanced phagocytic activity of macrophages was further verified afterin vitrotreatment with the VA samples. The protective mechanisms of the VA samples might include an immune enhancer and an inflammatory cytokine suppressor.

Fibrinogen binding to the integrin αIIbβ3 modulates store-mediated calcium entry in human platelets

Blood ◽  
2001 ◽  
Vol 97 (9) ◽  
pp. 2648-2656 ◽  
Author(s):  
Juan A. Rosado ◽  
Else M. Y. Meijer ◽  
Karly Hamulyak ◽  
Irena Novakova ◽  
Johan W. M. Heemskerk ◽  
...  
Keyword(s):  
Actin Cytoskeleton ◽  
Actin Polymerization ◽  
Adenosine Diphosphate ◽  
Inhibitory Effect ◽  
Human Platelets ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Integrin Αiibβ3 ◽  
Fibrinogen Binding

Abstract Effects of the occupation of integrin αIIbβ3 by fibrinogen on Ca++signaling in fura-2–loaded human platelets were investigated. Adding fibrinogen to washed platelet suspensions inhibited increases in cytosolic [Ca++] concentrations ([Ca++]i) evoked by adenosine diphosphate (ADP) and thrombin in a concentration-dependent manner in the presence of external Ca++ but not in the absence of external Ca++ or in the presence of the nonselective cation channel blocker SKF96365, indicating selective inhibition of Ca++entry. Fibrinogen also inhibited store-mediated Ca++ entry (SMCE) activated after Ca++ store depletion using thapsigargin. The inhibitory effect of fibrinogen was reversed if fibrinogen binding to αIIbβ3 was blocked using RDGS or abciximab and was absent in platelets from patients homozygous for Glanzmann thrombasthenia. Fibrinogen was without effect on SMCE once activated. Activation of SMCE in platelets occurs through conformational coupling between the intracellular stores and the plasma membrane and requires remodeling of the actin cytoskeleton. Fibrinogen inhibited actin polymerization evoked by ADP or thapsigargin in control cells and in cells loaded with the Ca++ chelator dimethyl BAPTA. It also inhibited the translocation of the tyrosine kinase p60src to the cytoskeleton. These results indicate that the binding of fibrinogen to integrin αIIbβ3 inhibits the activation of SMCE in platelets by a mechanism that may involve modulation of the reorganization of the actin cytoskeleton and the cytoskeletal association of p60src. This action may be important in intrinsic negative feedback to prevent the further activation of platelets subjected to low-level stimuli in vivo.

scholarly journals Sequestration of erythrocytes infected with Plasmodium berghei ANKA in BALB/c mice treated with goat bile

2020 ◽  
Vol 4 (2) ◽  
pp. 179
Author(s):  
Kartika Arum Wardani ◽  
Kholida Nur Aini ◽  
Heny Arwati ◽  
Willy Sandhika
Keyword(s):  
Plasmodium Berghei ◽  
Antimalarial Activity ◽  
Negative Control ◽  
Control Group ◽  
Dependent Manner ◽  
Plasmodium Berghei Anka ◽  
Concentration Dependent Manner ◽  
Control Group Design ◽  
Bile Concentration

Abstract Sequestration of Plasmodium berghei ANKA-infected erythrocytes occurs in BALB/c mice as characteristic of  Plasmodium falciparum infection in humans. Animals’ bile has been widely used for centuries in Traditional Chinese Medicine. Goat bile has been used in healing infectious and non-infectious diseases; however, no report on the use of goat bile against malaria infection and sequestration. The purpose of this study was to analyze the correlation between parasitemia and sequestration in the liver of P.berghei ANKA-infected BALB/c mice treated with goat bile. This research was an in vivo experimental study using the post-test control group design. The male BALB/c mice aged ± 6 weeks, body weight 20-25 g were used. The mice were divided into five groups where Group 1-3 were mice treated with goat bile 25%, 50%, and 100%, respectively. Group 4-5 were negative (sterile water) and positive controls (DHP). Parasitemia was observed daily from each mouse and the number of sequestered infected erythrocytes on the endothelium of sinusoids. The data were analyzed using t independent test. Antimalarial activity of goat bile was shown by the lower parasitemia in goat bile-treated mice compared with the negative control. The average number of sequestration was goat bile concentration-dependent manner. The higher the concentration, the lower the number of sequestration. Sequestration was correlated with parasitemia (p=0,0001). Sequestration of P.berghei ANKA-infected erythrocytes correlated with parasitemia, and was goat bile concentration-dependent manner. Keywords: Malaria, parasitemia, sequestration, goat bileCorrespondence: [email protected]

scholarly journals Inhibition of HepG-2 Cells (Liver Cancer Cell Line) Viability by 3-Hydroxypyridine-2-Carboxaldehyde N(4)-Methylthiosemicarbazone

2021 ◽  
Vol 8 (2) ◽  
pp. 88-97
Author(s):  
Edrees Khan Rahmatzada ◽  
Prof. Paras Nath Yadav ◽  
Dr. Yuba Raj Pokharel
Keyword(s):  
Cancer Cell Line ◽  
Mapk Signaling ◽  
In Vivo Model ◽  
Dependent Manner ◽  
Dapi Staining ◽  
Concentration Dependent Manner ◽  
Anticancer Effects ◽  
Ic50 Value ◽  
Colony Number

Thiosemicarbazone have the antiviral, antibacterial, antifungal, and anticancer effects. 3-OH-Me-TSC inhibited the cell viability of HepG-2 cells by CV assay in a concentration dependent manner (control, 1μM, 3μM, 10μM, 30μM, and 100μM) with IC50 value of 9.587622μM. Further colony formation assay demonstrated that 3-OH-Me-TSC inhibits colony number and size of HepG-2. Wound healing assay exhibited that 3-OH-Me-TSC inhibit the migration of HepG-2 cells. DAPI staining showed that 3-OH-Me-TSC inhibited proliferation of HepG-2 cells in 30μM and 100μM concentrations respectively. 3-OH-Me-TSC inhibited VEGF, p38 alpha, C-JUN, BECN-1, ERK, NF-KB, in HepG-2 cells. We found that 3-OH-Me-TSC inhibit proliferation of HepG-2 cells by inhibiting MAPK signaling pathway, 3-OH-Me-TSC can be developed as future chemotherapeutic agent for treatment of hepatocellular carcinoma after the evaluation of this compounds in more cancer cells an in vivo model.

scholarly journals Assessment of Antioxidant and Antimicrobial Activities of Silver Nanoparticles Biosynthesized by Haplophyllum Obtusifolium

2020 ◽  
Vol 8 (2) ◽  
pp. 94-98
Author(s):  
Mohammad Reza Rezaei ◽  
Ali Es-haghi ◽  
Parichehreh Yaghmaei ◽  
Maryam Ghobeh
Keyword(s):  
Antioxidant Activity ◽  
Silver Nanoparticles ◽  
Antimicrobial Agents ◽  
Antioxidant Activities ◽  
Antimicrobial Activities ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
The North ◽  
Chamber Temperature ◽  
Pharmaceutical Industries

Background: Plants comprise great antioxidant sources as a result of their redox and biochemical components, which are rich in secondary metabolites such as phenolic acids, flavonoids, and other constituents. Haplophyllum obtusifolium from polygonaceae is widely used for preventing and managing diabetes. This study investigated the antibacterial and antioxidant activities of silver nanoparticles (AgNPs) biosynthesized by H. obtusifolium. Methods: The aerial parts of H. obtusifolium were gathered from the north of Khorasan Razavi province, Iran and desiccated at the chamber temperature. The shoots were powdered by grinding, 5 g of the powder was mixed with 250 mL of deionized water, and the resultant blend was then filtered. Bactericidal properties and antioxidant activity of the nanoparticles were assessed using disk diffusion and DPPH (2, 2-diphenyl-1-picrylhydrazyl) tests, respectively. Results: The results of this study showed that the biosynthesized nanoparticles exhibited antibacterial activity against a gram-negative (Klebsiella pneumoniae) bacterium, but they had no effects on gram-positive Staphylococcus epidermidis. Antioxidant test results showed that these nanoparticles were capable of eliminating DPPH radicals in a concentration-dependent manner so that a more potent antioxidant activity was seen in higher concentrations of the nanoparticles. Conclusion: Our results suggested that H. obtusifolium can be used as a key source of antioxidants/ antimicrobial agents in food and pharmaceutical industries.

Effect of Auraptene on angiogenesis in Xenograft model of breast cancer

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Mohammad Reza Shiran ◽  
Elham Mahmoudian ◽  
Abolghasem Ajami ◽  
Seyed Mostafa Hosseini ◽  
Ayjamal Khojasteh ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Gene Expression ◽  
Animal Model ◽  
Protein Expression ◽  
Western Blot ◽  
Xenograft Model ◽  
Dependent Manner ◽  
Concentration Dependent Manner

Abstract Objectives Angiogenesis is the most important challenge in breast cancer treatment. Recently, scientists become interesting in rare natural products and intensive researches was performed to identify their pharmacological profile. Auraptene shows helpful effects such as cancer chemo-preventive, anti-inflammatory, anti-oxidant, immuno-modulatory. In this regard, we investigated the anti-angiogenesis effect of Auraptene in in-vitro and in-vivo model of breast cancer. Methods In this study, 4T, MDA-MB-231 and HUVEC cell lines were used. The proliferation study was done by MTT assay. For tube formation assay, 250 matrigel, 1 × 104 HUVEC treated with Auraptene, 20 ng/mL EGF, 20 ng/mL bFGF and 20 ng/mL VEGF were used. Gene expression of important gene related to angiogenesis in animal model of breast cancer was investigated by Real-time PCR. Protein expression of VCAM-1 and TNFR-1 gene related to angiogenesis in animal model of breast cancer was investigated by western-blot. Results Auraptene treatment led to reduction in cell viability of MDA-MB-231 in a concentration-dependent manner. Also, we observed change in the number of tubes or branches formed by cells incubated with 40 and 80 μM Auraptene. Auraptene effect the gene expression of important gene related to angiogenesis (VEGF, VEGFR2, COX2, IFNɣ). Moreover, the western blot data exhibited that Auraptene effect the protein expression of VCAM-1 and TNFR-1. Conclusions Overall, this study shows that Auraptene significantly suppressed angiogenesis via down-regulation of VEGF, VEGFR2, VCAM-1, TNFR-1, COX-2 and up-regulation of IFNγ.

Sign in / Sign up

Export Citation Format

Share Document