scholarly journals Antimicrobial Defensin and DNA Traps in Manila Clam Ruditapes philippinarum: Implications for Their Roles in Immune Responses

2021 ◽  
Vol 8 ◽  
Author(s):  
Yijing Han ◽  
Gege Hu ◽  
Yuying Chen ◽  
Lizhu Chen ◽  
Daode Yu ◽  
...  
Keyword(s):  
Vibrio Parahaemolyticus ◽  
Defense Mechanism ◽  
Antimicrobial Effect ◽  
Ruditapes Philippinarum ◽  
Gram Negative Bacteria ◽  
Dependent Manner ◽  
Gram Positive Bacteria ◽  
Extracellular Traps ◽  
Bacterial Stimulation ◽  
Dose Dependent

Although defensins have been isolated from a variety of metazoan, their role in cellular immunity has not been answered. In the study, we found that the hemocytes of the Manila clams Ruditapes philippinarum release defensin (designated as Rpdef3) in response to Vibrio parahaemolyticus challenge. The antimicrobial Rpdef3 was proved to be involved in the extracellular traps (ETs) that hemocytes released in response to Vibrio challenge. Scanning electron microscopy observation proved the patterns how ETs eliminate invading bacteria. Furthermore, Rpdef3 involved in ETs had broad-spectrum antimicrobial effect on both Gram-negative bacteria and Gram-positive bacteria. ELISA assay revealed that Rpdef3 could bind lipopolysaccharides and peptidoglycan in a dose-dependent manner. As concerned to the antibacterial mechanisms, Rpdef3 can cause bacterial membrane permeabilization, leading to cell death. As a result, Rpdef3 might contribute to the trap and the elimination of invading Vibrio in clam ETs. Taken together, our study suggest that the formation of ETs is a defense mechanism triggered by bacterial stimulation, coupled with antibacterial defensin.

scholarly journals Evaluation of T-3811ME (BMS-284756), a New Des-F(6)-Quinolone, for Treatment of Meningitis Caused by Penicillin-Resistant Streptococcus pneumoniae in Rabbits

2002 ◽  
Vol 46 (6) ◽  
pp. 1760-1765 ◽  
Author(s):  
Masahiro Takahata ◽  
Hiroshi Yamada ◽  
Teiichi Morita ◽  
Shinichi Furubou ◽  
Shinzaburo Minami ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Viable Cell ◽  
Treated Group ◽  
Dependent Manner ◽  
Free Base ◽  
Time Curve ◽  
Gram Positive Bacteria ◽  
Cell Counts ◽  
Concentration Time ◽  
Dose Dependent

ABSTRACT T-3811ME (BMS-284756) is a new des-F(6)-quinolone with high levels of activity against gram-positive bacteria, including penicillin-resistant Streptococcus pneumoniae (PRSP) strains. T-3811, the free base of T-3811ME, exhibited potent activity against 28 clinical strains of PRSP isolated clinically (MIC at which 90% of the isolates tested are inhibited, 0.0625 μg/ml). After the intravenous dosing of T-3811ME (20 mg/kg of body weight as T-3811) in rabbits with meningitis caused by PRSP, the area under the concentration-time curve (AUC) of T-3811 in cerebrospinal fluid (CSF) was 5.79 μg · h/ml and was 4.5-fold higher than that of T-3811in the CSF of rabbits without meningitis. In addition, the AUC/MIC for T-3811ME (20 mg/kg as T-3811) in CSF was 185, which was 4.3-fold higher than that for ceftriaxone (administered intravenously at 100 mg/kg). After the administration of any dose of T-3811ME (5, 10, and 20 mg/kg as T-3811), the viable cell counts in CSF decreased in a dose-dependent manner. In particular, after dosing of 20 mg/kg (as T-3811), the viable cell counts in CSF were significantly less than those in the nontreated group (P < 0.01). By histopathological evaluation, 6 h after the administration of T-3811ME (20 mg/kg as T-3811), the thickening of the cerebral meninx and the infiltration of neutrophils into the cerebral meninx were less severe in the treated group than in the nontreated group. T-3811ME (BMS-284756) may be expected to be evaluated for the management of meningitis caused by highly penicillin-resistant pneumococci.

scholarly journals Antimicrobial Effect of Bacteriocin produced Pediococcus pentosaceus on some clinical isolates

2017 ◽  
Vol 27 (5) ◽  
pp. 26 ◽  
Author(s):  
Nehad A. Taher
Keyword(s):  
Antimicrobial Activity ◽  
Protein Concentration ◽  
Antimicrobial Effect ◽  
Clinical Isolates ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Pediococcus Pentosaceus ◽  
Gram Positive Bacteria ◽  
Agar Plug ◽  
Made In

About 10 isolates of Pediococcus sp were isolated from different cheese made in Iraq, These isolates were identified morphologically and biochemically and Api20 kit, thus there was only 6 isolate were identified as Pediococcus pentosaceus (60%).In this study, we investigate, the effect of crude Bacteriocin from Pediococcus pentosaceus on 30 clinical isolates (5 E.coli, 5 Klepsiella pneumoniae, 5 Staphylococcus aureus, 5 Pseudomonas aeroginosa, 5 Bacillus subtilis, 5 Candida albicans). The protein concentration of this Bacteriocin was measured 67mg\ml by Bradford method and used as (1:2) by vol during the measuring the antimicrobial activity against the above clinical isolates by two methods wells and  agar plug assay. The results showed that  the inhibitory activity of this Bacteriocin was higher by wells method than agar pluq assay against Gram–positive bacteria or Gram-negative bacteria and yeast under this study.

scholarly journals Neisseria gonorrhoeae Evades Calprotectin-Mediated Nutritional Immunity and Survives Neutrophil Extracellular Traps by Production of TdfH

2016 ◽  
Vol 84 (10) ◽  
pp. 2982-2994 ◽  
Author(s):  
Sophonie Jean ◽  
Richard A. Juneau ◽  
Alison K. Criss ◽  
Cynthia N. Cornelissen
Keyword(s):  
Neisseria Gonorrhoeae ◽  
Defense Mechanism ◽  
Outer Membrane Proteins ◽  
Neutrophil Extracellular Traps ◽  
Host Protein ◽  
Dependent Manner ◽  
Bacterial Survival ◽  
Content Type ◽  
Extracellular Traps ◽  
Nutritional Immunity

Neisseria gonorrhoeaesuccessfully overcomes host strategies to limit essential nutrients, termed nutritional immunity, by production of TonB-dependent transporters (TdTs)—outer membrane proteins that facilitate nutrient transport in an energy-dependent manner. Four gonococcal TdTs facilitate utilization of iron or iron chelates from host-derived proteins, including transferrin (TbpA), lactoferrin (LbpA), and hemoglobin (HpuB), in addition to xenosiderophores from other bacteria (FetA). The roles of the remaining four uncharacterized TdTs (TdfF, TdfG, TdfH, and TdfJ) remain elusive. Regulatory data demonstrating that production of gonococcal TdfH and TdfJ are unresponsive to or upregulated under iron-replete conditions led us to evaluate the role of these TdTs in the acquisition of nutrients other than iron. In this study, we found that production of gonococcal TdfH is both Zn and Zur repressed. We also found that TdfH confers resistance to calprotectin, an immune effector protein highly produced in neutrophils that has antimicrobial activity due to its ability to sequester Zn and Mn. We found that TdfH directly binds calprotectin, which enables gonococcal Zn accumulation in a TdfH-dependent manner and enhances bacterial survival after exposure to neutrophil extracellular traps (NETs). These studies highlight Zn sequestration by calprotectin as a key functional arm of NET-mediated killing of gonococci. We demonstrate for the first time thatN. gonorrhoeaeexploits this host strategy in a novel defense mechanism, in which TdfH production hijacks and directly utilizes the host protein calprotectin as a zinc source and thereby evades nutritional immunity.

Studies on the Antimicrobial Activity of Juglans regia

1997 ◽  
Vol 25 (02) ◽  
pp. 175-180 ◽  
Author(s):  
Abdulaziz M. Alkhawajah
Keyword(s):  
Antimicrobial Activity ◽  
Juglans Regia ◽  
Dependent Manner ◽  
Pathogenic Yeast ◽  
Gram Positive Bacteria ◽  
Additive Action ◽  
Esherichia Coli ◽  
Wide Range ◽  
Micro Organisms ◽  
Dose Dependent

Juglans regia L. bark is used in some countries as a toothbrush and as a dye for coloring the lips for cosmetic purposes. Its extract showed a broad spectrum antimicrobial activity in a dose dependent manner. It inhibited the growth of several species of pathogenic micro-organisms representing Gram-positive bacteria (Staphylococcus aureus and Streptococcus mutans), Gram-negative bacteria (Esherichia coli and Pseudomonas aeruginosa) and a pathogenic yeast (Candida albicans). The extract has either synergistic or additive action when tested with a wide range of antibacterial drugs. It also increased the pH of saliva. Thus, brushing the teeth with this bark may improve oral hygiene, prevent plaque and caries formation, and reduce the incidence of gingival and periodontal infections.

scholarly journals Rapid and Direct Action of Lipopolysaccharide (LPS) on Skeletal Muscle of Larval Drosophila

Biology ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1235
Author(s):  
Rachel Potter ◽  
Alexis Meade ◽  
Samuel Potter ◽  
Robin L. Cooper
Keyword(s):  
Skeletal Muscle ◽  
Direct Action ◽  
Gram Negative Bacteria ◽  
Dependent Manner ◽  
Cellular Energy ◽  
Energy Demands ◽  
Cl Channels ◽  
Calcium Activated Potassium Channels ◽  
Oxide Synthase ◽  
Dose Dependent

The endotoxin lipopolysaccharide (LPS) from Gram-negative bacteria exerts a direct and rapid effect on tissues. While most attention is given to the downstream actions of the immune system in response to LPS, this study focuses on the direct actions of LPS on skeletal muscle in Drosophila melanogaster. It was noted in earlier studies that the membrane potential rapidly hyperpolarizes in a dose-dependent manner with exposure to LPS from Pseudomonas aeruginosa and Serratia marcescens. The response is transitory while exposed to LPS, and the effect does not appear to be due to calcium-activated potassium channels, activated nitric oxide synthase (NOS), or the opening of Cl− channels. The purpose of this study was to further investigate the mechanism of the hyperpolarization of the larval Drosophila muscle due to exposure of LPS using several different experimental paradigms. It appears this response is unlikely related to activation of the Na-K pump or Ca2+ influx. The unknown activation of a K+ efflux could be responsible. This will be an important factor to consider in treatments of bacterial septicemia and cellular energy demands.

scholarly journals Mechanistic Study of Synergistic Antimicrobial Effects between Poly (3-hydroxybutyrate) Oligomer and Polyethylene Glycol

2020 ◽  
Author(s):  
Ziheng Zhang ◽  
Jun Li ◽  
Linlin Ma ◽  
Xingxing Yang ◽  
Bin Fei ◽  
...  
Keyword(s):  
Polyethylene Glycol ◽  
Antimicrobial Agents ◽  
Antimicrobial Effect ◽  
Mechanistic Study ◽  
Resistant Bacteria ◽  
Gram Negative Bacteria ◽  
Drug Resistant ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Drug Resistant Bacteria

We reported previously that poly (3-hydroxybutyrate) (PHB) oligomer is an effective antimicrobial agent against gram-positive bacteria, gram-negative bacteria, fungi and multi-drug resistant bacteria. In this work, it was further found that polyethylene glycol (PEG) can promote the antimicrobial effect of PHB oligomer synergistically. Three hypothetic mechanisms were proposed, that is, generation of new antimicrobial components, degradation of PHB macromolecules and dissolution/dispersion of PHB oligomer by PEG. With a series of systematic experiments and characterizations of HPLC-MS, it was deducted that dissolution/dispersion of PHB oligomer dominated the synergistic antimicrobial effect between PHB oligomer and PEG. This work demonstrates a way for promoting antimicrobial effect of PHB oligomer and other antimicrobial agents through improving hydrophilicity.

Antioxidant and Antimicrobial Activity of Tellurium Dioxide Nanoparticles Sols

2013 ◽  
Vol 25 ◽  
pp. 8-15 ◽  
Author(s):  
Cai Ling Zhong ◽  
Bi Yin Qin ◽  
Xin Yuan Xie ◽  
Yan Bai
Keyword(s):  
Antioxidant Activity ◽  
Acetic Acid ◽  
Gallic Acid ◽  
Antimicrobial Effect ◽  
Dependent Manner ◽  
Tellurium Dioxide ◽  
Gram Positive Bacteria ◽  
Bioassay Method ◽  
Agar Diffusion ◽  
Antioxidant And Antimicrobial Activity

In this study, the antioxidant activity and antimicrobial effect of tellurium dioxide nanoparticles (TeO2NPs) sols were evaluated by oxygen radical absorbance capacity (ORAC) and agar diffusion bioassay method, respectively. The results of ORAC demonstrated that the antioxidant activity of TeO2NPs sols was in a dose-dependent manner and TeO2NPs-gallic acid sol showed stronger antioxidant activity than TeO2NPs-acetic acid sol due to the synergistic antioxidant effect of gallic acid and TeO2NPs. On the other hand, the results of agar diffusion bioassay method demonstrated that the antimicrobial effect of TeO2NPs-acetic acid sol was stronger than that of TeO2NPs-gallic acid sol and the two kinds of TeO2NPs sols could evidently inhibit the growth of some gram negative bacteria and gram positive bacteria which lack nitrate reductase. The antimicrobial mechanism of the TeO2NPs sols might be similar to that of tellurite.

scholarly journals Anticomplement and Antimicrobial Activities of Flavonoids from Entada phaseoloides

2012 ◽  
Vol 7 (7) ◽  
pp. 1934578X1200700 ◽  
Author(s):  
Ke Li ◽  
Shihua Xing ◽  
Mengyue Wang ◽  
Ying Peng ◽  
Yuqiong Dong ◽  
...  
Keyword(s):  
Pathogenic Fungus ◽  
Antimicrobial Activities ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Alternative Pathways ◽  
Gram Positive Bacteria ◽  
Dependent Activity ◽  
Entada Phaseoloides ◽  
Inhibitory Activities ◽  
Dose Dependent

Seventeen flavonoids isolated from the extracts of the stem of Entada phaseoloides were investigated for their anticomplement (both classic and alternative pathways) and antimicrobial activities against Gram-positive bacteria (MRSA, MSSA, Standard Enterococcus and Bacillus subtilis), Gram-negative bacteria ( Escherichia coli, Pseudomonas aeuroginosa) and the yeast-like pathogenic fungus Candida albicans. The anticomplement studies revealed a dose-dependent activity among isolated quercetin, luteolin, apigenin, galangin, 5,2′,5′-trihydroxy-3,7,4′-trimethoxyflavone-2′-O-β-D-glucoside (+)-3,3′,5′,5,7-pentahydroflavanone, (+)-dihydrokaempferol, (-)-epicatechin, (+)-catechin, naringenin, and 5,7,3′,5′-tetrahydroxyflavanone, and the antimicrobial results indicated that quercetin, 5,7,4′-trihydroxy-3′-methoxyflavonol and galangin produced the inhibitory activities against MRSA, MSSA, and Standard Enterococcus, while luteolin and rhamnocitrin displayed inhibition against only MRSA and MSSA. To the best of our knowledge, this is the first report that describes the anticomplement and antimicrobial activities of the stem of E. phaseoloides.

scholarly journals EVALUATION OF ANTIMICROBIAL, CYTOTOXICITY, AND DYEING PROPERTIES OF PRODIGIOSIN PRODUCED BY SERRATIA MARCESCENS STRAIN JAR8

2017 ◽  
Vol 10 (8) ◽  
pp. 279
Author(s):  
Ritika Chauhan ◽  
Aniket Choudhuri ◽  
Jayanthi Abraham
Keyword(s):  
Incubation Period ◽  
Potent Inhibitor ◽  
Bone Cancer ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Dyeing Properties ◽  
Gram Positive Bacteria ◽  
Production Parameters ◽  
The Media ◽  
Dose Dependent

  Objective: Prodigiosin is a red tripyrrole pigment which is synthesized as a secondary metabolite by biotypes A1, A2, and A6 of Serretia marcescens. This study was aimed to optimize production parameters for prodigiosin pigment produced by S. marcescens strain JAR8 and to determine its antimicrobial, cytotoxicity, and dyeing properties.Methods: The effect of various media components, process parameters (temperature, pH, incubation period), and other supplements was investigated, and the maximum production of prodigiosin was found to be at temperature 28°C, pH 7.0, incubation period of 5 day with peptone in the media. Antibacterial, cytotoxicity, and dyeing properties of prodigiosin were studied in depth.Results: The antimicrobial study of prodigiosin revealed that it is a potent inhibitor of Gram-positive bacteria as well as Gram-negative bacteria. The prodigiosin exhibited commendable dose-dependent cytotoxicity effect against human bone cancer cells with the IC50 of 108 μg/ml. Prodigiosin produced by strain JAR8 resisted the action of acid, alkali and detergent when applied to textile cloth.Conclusion: The deep red pigment prodigiosin produced by strain JAR8 is economically effective and can be categorized as microbial natural product for further pharmaceutical applications.

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