scholarly journals Reduced biological control and enhanced chemical pest management in the evolution of fungus farming in ants

2009 ◽  
Vol 276 (1665) ◽  
pp. 2263-2269 ◽  
Author(s):  
Hermógenes Fernández-Marín ◽  
Jess K. Zimmerman ◽  
David R. Nash ◽  
Jacobus J. Boomsma ◽  
William T. Wcislo
Keyword(s):  
Biological Control ◽  
Exocrine Glands ◽  
Relative Importance ◽  
Fungal Symbiont ◽  
Metapleural Glands ◽  
Spectrum Activity ◽  
Fungus Growing Ants ◽  
Antimicrobial Metabolites ◽  
And Control ◽  
Broad Spectrum Activity

To combat disease, most fungus-growing ants (Attini) use antibiotics from mutualistic bacteria ( Pseudonocardia ) that are cultured on the ants' exoskeletons and chemical cocktails from exocrine glands, especially the metapleural glands (MG). Previous work has hypothesized that (i) Pseudonocardia antibiotics are narrow-spectrum and control a fungus ( Escovopsis ) that parasitizes the ants' fungal symbiont, and (ii) MG secretions have broad-spectrum activity and protect ants and brood. We assessed the relative importance of these lines of defence, and their activity spectra, by scoring abundance of visible Pseudonocardia for nine species from five genera and measuring rates of MG grooming after challenging ants with disease agents of differing virulence. Atta and Sericomyrmex have lost or greatly reduced the abundance of visible bacteria. When challenged with diverse disease agents, including Escovopsis , they significantly increased MG grooming rates and expanded the range of targets. By contrast, species of Acromyrmex and Trachymyrmex maintain abundant Pseudonocardia. When challenged, these species had lower MG grooming rates, targeted primarily to brood. More elaborate MG defences and reduced reliance on mutualistic Pseudonocardia are correlated with larger colony size among attine genera, raising questions about the efficacy of managing disease in large societies with chemical cocktails versus bacterial antimicrobial metabolites.

scholarly journals Antimicrobial Metabolites Profile and Inhibitory Activity of Streptomyces xinghaiensis-OY62 Isolated from Soil against Indicator Strains

2018 ◽  
pp. 1-15
Author(s):  
O. M. Adeyemo ◽  
A. A. Onilude
Keyword(s):  
Antimicrobial Activity ◽  
16S Rdna ◽  
Broad Spectrum ◽  
Partial Purification ◽  
Southwestern Nigeria ◽  
Cultural Conditions ◽  
Microbial Infections ◽  
Spectrum Activity ◽  
Antimicrobial Metabolites ◽  
Broad Spectrum Activity

Aims: The aims of this study were to screen for potential broad-spectrum antimicrobial-producing actinomycetes from the tropical rain forest of Oyo State, Nigeria, to assess the effects of cultural conditions on antimicrobial metabolites, characterize the metabolites and determine its antimicrobial activity against indicator strains. Place and Duration of the Study: Department of Microbiology, University of Ibadan, Ibadan, between April 2014 and August 2016. Methodology: Ten soil samples were purposively collected between April and June 2014 for the isolation of Actinomycetes. The isolated strain was identified culturally and molecularly using 16S rDNA. The effect of cultural parameters on antimicrobial activity was done by a standard method. The antimicrobial metabolites were produced by submerged fermentation. Partial purification was carried out by column chromatography. Chemical characteristics of the metabolites were determined by Fourier transformed infra-red spectrometer (FTIR) and gas chromatography coupled with a mass spectrometer. The antimicrobial activity was done by agar well diffusion and macro broth dilution. Results: Isolate OY62 had broad-spectrum antimicrobial activity and it was identified using its 16S rDNA gene as Streptomyces xinghaiensis-OY62 (KU934248). The highest antimicrobial activity against indicator strains was recorded between pH 7 and pH 8, 0.8% (w/v) sodium chloride, at elevated temperature 55°C, casein+KNO3 as a nitrogen source, starch or absence of carbon source and incubation period of fifteen days. Aliphatic alkene, hydroxyl, carboxylic acids, amides and carbonyls were functional groups detected while thirteen antimicrobial metabolites were characterized. The MIC against indicator strains was between 6.25 mg/L to 12.5 mg/L. Streptomyces xinghaiensis-OY62 exhibited broad-spectrum activity against indicator strains. Conclusion: The observed results showed that potential broad-spectrum antimicrobial-producing strains of Streptomyces could be isolated from the soil of southwestern Nigeria, which could be useful in the production of antimicrobials that can inhibit the growth of resistant pathogens, reduce microbial infections and death.

scholarly journals Biological control of bacterial plant diseases withLactobacillus plantarumstrains selected for their broad-spectrum activity

2018 ◽  
Vol 174 (1) ◽  
pp. 92-105 ◽  
Author(s):  
Núria Daranas ◽  
Gemma Roselló ◽  
Jordi Cabrefiga ◽  
Irene Donati ◽  
Jesús Francés ◽  
...  
Keyword(s):  
Biological Control ◽  
Broad Spectrum ◽  
Plant Diseases ◽  
Spectrum Activity ◽  
Broad Spectrum Activity

Antimicrobial Peptides: A Promising Avenue for Human Healthcare

2020 ◽  
Vol 21 (2) ◽  
pp. 90-96 ◽  
Author(s):  
Girish M. Bhopale
Keyword(s):  
Antimicrobial Peptides ◽  
Antimicrobial Peptide ◽  
Antimicrobial Agents ◽  
Current Status ◽  
Antimicrobial Drugs ◽  
Spectrum Activity ◽  
Low Levels ◽  
Human Healthcare ◽  
Broad Spectrum Activity ◽  
Promising Avenue

Antimicrobial drugs resistant microbes have been observed worldwide and therefore alternative development of antimicrobial peptides has gained interest in human healthcare. Enormous progress has been made in the development of antimicrobial peptide during the last decade due to major advantages of AMPs such as broad-spectrum activity and low levels of induced resistance over the current antimicrobial agents. This review briefly provides various categories of AMP, their physicochemical properties and mechanism of action which governs their penetration into microbial cell. Further, the recent information on current status of antimicrobial peptide development, their applications and perspective in human healthcare are also described.

scholarly journals AcrAB Multidrug Efflux Pump Is Associated with Reduced Levels of Susceptibility to Tigecycline (GAR-936) in Proteus mirabilis

2003 ◽  
Vol 47 (2) ◽  
pp. 665-669 ◽  
Author(s):  
Melissa A. Visalli ◽  
Ellen Murphy ◽  
Steven J. Projan ◽  
Patricia A. Bradford
Keyword(s):  
Proteus Mirabilis ◽  
Efflux Pump ◽  
Wild Type ◽  
Multidrug Efflux ◽  
Multidrug Efflux Pump ◽  
Transposon Insertion ◽  
Spectrum Activity ◽  
Insertion Mutants ◽  
Broad Spectrum Activity ◽  
Increased Susceptibility

ABSTRACT Tigecycline has good broad-spectrum activity against many gram-positive and gram-negative pathogens with the notable exception of the Proteeae. A study was performed to identify the mechanism responsible for the reduced susceptibility to tigecycline in Proteus mirabilis. Two independent transposon insertion mutants of P. mirabilis that had 16-fold-increased susceptibility to tigecycline were mapped to the acrB gene homolog of the Escherichia coli AcrRAB efflux system. Wild-type levels of decreased susceptibility to tigecycline were restored to the insertion mutants by complementation with a clone containing a PCR-derived fragment from the parental wild-type acrRAB efflux gene cluster. The AcrAB transport system appears to be associated with the intrinsic reduced susceptibility to tigecycline in P. mirabilis.

scholarly journals Discovery and Characterization of a Novel CD4-Binding Adnectin with Potent Anti-HIV Activity

2017 ◽  
Vol 61 (8) ◽  
Author(s):  
David Wensel ◽  
Yongnian Sun ◽  
Zhufang Li ◽  
Sharon Zhang ◽  
Caryn Picarillo ◽  
...  
Keyword(s):  
Conformational Changes ◽  
Viral Entry ◽  
High Affinity ◽  
Glycosylation Sites ◽  
Spectrum Activity ◽  
Anti Hiv ◽  
Hiv 1 ◽  
Broad Spectrum Activity

ABSTRACT A novel fibronectin-based protein (Adnectin) HIV-1 inhibitor was generated using in vitro selection. This inhibitor binds to human CD4 with a high affinity (3.9 nM) and inhibits viral entry at a step after CD4 engagement and preceding membrane fusion. The progenitor sequence of this novel inhibitor was selected from a library of trillions of Adnectin variants using mRNA display and then further optimized for improved antiviral and physical properties. The final optimized inhibitor exhibited full potency against a panel of 124 envelope (gp160) proteins spanning 11 subtypes, indicating broad-spectrum activity. Resistance profiling studies showed that this inhibitor required 30 passages (151 days) in culture to acquire sufficient resistance to result in viral titer breakthrough. Resistance mapped to the loss of multiple potential N-linked glycosylation sites in gp120, suggesting that inhibition is due to steric hindrance of CD4-binding-induced conformational changes.

Metabolic influences on satiety in rats receiving parenteral nutrition

1994 ◽  
Vol 266 (2) ◽  
pp. R381-R386 ◽  
Author(s):  
J. L. Beverly ◽  
M. M. Meguid ◽  
Z. J. Yang ◽  
M. X. Yue ◽  
B. L. Fetterman
Keyword(s):  
Fatty Acid ◽  
Food Intake ◽  
Parenteral Nutrition ◽  
Metabolic Energy ◽  
Acid Oxidation ◽  
Relative Importance ◽  
Phase 2 ◽  
Light Phase ◽  
Single Intraperitoneal Injection ◽  
And Control

Food intake is reduced during parenteral nutrition (PN) proportionally to the amount of calories or composition of the solution infused. The relative importance of infused glucose and lipid, 50 and 30% of PN kilocalories, respectively, in reducing food intake during PN was examined. Glycolysis, fatty acid oxidation, or both were acutely disrupted with 2-deoxy-D-glucose (2-DG) and mercaptoacetate (MA). Rats receiving intravenous infusions of saline or a PN solution providing 100% of total daily calories (PN-100) received a single intraperitoneal injection of saline, 2-DG, and/or MA during the early light phase. 2-DG (1.4 or 2.2 mmol/kg) did not initiate feeding in PN-100 rats, although hyperglycemia was evident in all rats 1 h after 2-DG. Food intake of PN-100 rats after MA (0.4 mmol/kg) was approximately 50% that of control rats. When 2-DG (1.4 mmol/kg) and MA (0.4 mmol/kg) were administered concomitantly, PN-100 and control rats consumed the same amount of food. During PN-100, rats appeared to be more sensitive to losing metabolic energy derived from lipid than from glucose.

scholarly journals Five-Year Longitudinal Assessment (2008 to 2012) of E-101 Solution Activity against Clinical Target and Antimicrobial-Resistant Pathogens

2014 ◽  
Vol 58 (8) ◽  
pp. 4911-4914 ◽  
Author(s):  
Gerald A. Denys ◽  
Chris M. Pillar ◽  
Daniel F. Sahm ◽  
Peter O'Hanley ◽  
Jackson T. Stephens
Keyword(s):  
Broad Spectrum ◽  
Susceptibility Testing ◽  
Bacterial Species ◽  
Clinical Isolates ◽  
Longitudinal Assessment ◽  
Gram Negative ◽  
Spectrum Activity ◽  
Eskape Pathogens ◽  
Negative Target ◽  
Broad Spectrum Activity

ABSTRACTThis study summarizes the topical E-101 solution susceptibility testing results for 760 Gram-positive and Gram-negative target pathogens collected from 75 U.S. sites between 2008 and 2012 and 103 ESKAPE pathogens. E-101 solution maintained potent activity against all bacterial species studied for each year tested, with MICs ranging from <0.008 to 0.25 μg porcine myeloperoxidase (pMPO)/ml. These results confirm that E-101 solution retains its potent broad-spectrum activity against U.S. clinical isolates and organisms with challenging resistance phenotypes.

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