scholarly journals Classification of antimicrobial mechanism of action using bacterial time-lapse imaging

2021 ◽  
Author(s):  
Xudong Ouyang ◽  
Jelmer Hoeksma ◽  
Tjalling K. Siersma ◽  
Leendert W. Hamoen ◽  
Jeroen den Hertog
Keyword(s):  
Mechanism Of Action ◽  
Morphological Changes ◽  
Time Lapse ◽  
Basic Knowledge ◽  
Imaging Method ◽  
Fungal Culture ◽  
Bacterial Cells ◽  
Simple Method ◽  
Antimicrobial Mechanism

AbstractAntimicrobial resistance is a major threat to human health. Basic knowledge of antimicrobial mechanism of action (MoA) is imperative for patient care and for identification of novel antimicrobials. However, the process of antimicrobial MoA identification is relatively laborious. Here, we developed a simple, quantitative time-lapse fluorescence imaging method, Dynamic Bacterial Morphology Imaging (DBMI), to facilitate this process. It uses a membrane dye and a nucleoid dye to track the morphological changes of single Bacillus subtilis cells in response to antimicrobials for up to 60 min. DBMI of bacterial cells facilitated assignment of the MoAs of 14 distinct, known antimicrobial compounds to the five main classes. Using this method, we found that the poorly studied antimicrobial, harzianic acid, a secondary metabolite that we purified from the fungal culture of Oidiodendron flavum, targets the cell envelope. We conclude that DBMI is a simple method, which facilitates rapid classification of the MoA of antimicrobials in functionally distinct classes.

scholarly journals Peptide-Lipid Huge Toroidal Pore, a New Antimicrobial Mechanism Mediated by a Lactococcal Bacteriocin, Lacticin Q

2009 ◽  
Vol 53 (8) ◽  
pp. 3211-3217 ◽  
Author(s):  
Fuminori Yoneyama ◽  
Yuichi Imura ◽  
Kanako Ohno ◽  
Takeshi Zendo ◽  
Jiro Nakayama ◽  
...  
Keyword(s):  
Fluorescent Protein ◽  
Morphological Changes ◽  
Bacterial Cells ◽  
Flip Flop ◽  
Pore Model ◽  
Small Proteins ◽  
Protein Leakage ◽  
Antimicrobial Mechanism ◽  
Toroidal Pore ◽  
Calcein Leakage

ABSTRACT Lacticin Q is a pore-forming bacteriocin produced by Lactococcus lactis QU 5, and its antimicrobial activity is in the nanomolar range. Lacticin Q induced calcein leakage from negatively charged liposomes. However, no morphological changes in the liposomes were observed by light scattering. Concomitantly with the calcein leakage, lacticin Q was found to translocate from the outer to the inner leaflet of the liposomes, after it initially bound to the membrane within 2 s. Lacticin Q also induced lipid flip-flop. These results reveal that the antimicrobial mechanism of lacticin Q can be described by the toroidal pore model. This is the first report of a bacteriocin of gram-positive bacteria that forms a toroidal pore. From liposomes, lacticin Q leaked fluorescence-labeled dextran with a diameter of 4.6 nm. In addition, lacticin Q caused the leakage of small proteins, such as the green fluorescent protein, from live bacterial cells. There are no other reports of antimicrobial peptides that exhibit protein leakage properties. The proposed pore formation model of lacticin Q is as follows: (i) quick binding to outer membrane leaflets; (ii) the formation of at least 4.6-nm pores, causing protein leakage with lipid flip-flop; and (iii) the migration of lacticin Q molecules from the outer to the inner membrane leaflets. Consequently, we termed the novel pore model in the antimicrobial mechanism of lacticin Q a “huge toroidal pore.”

scholarly journals Zinc Oxide and Silver Nanoparticle Effects on Intestinal Bacteria

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2489
Author(s):  
Ami Yoo ◽  
Mengshi Lin ◽  
Azlin Mustapha
Keyword(s):  
Electron Microscopy ◽  
Zinc Oxide ◽  
Morphological Changes ◽  
Intestinal Bacteria ◽  
Bacterial Cells ◽  
Ag Nps ◽  
Zno Nps ◽  
Bifidobacterium Animalis ◽  
Transmission Electron

The application of nanoparticles (NPs) for food safety is increasingly being explored. Zinc oxide (ZnO) and silver (Ag) NPs are inorganic chemicals with antimicrobial and bioactive characteristics and have been widely used in the food industry. However, not much is known about the behavior of these NPs upon ingestion and whether they inhibit natural gut microflora. The objective of this study was to investigate the effects of ZnO and Ag NPs on the intestinal bacteria, namely Escherichia coli, Lactobacillus acidophilus, and Bifidobacterium animalis. Cells were inoculated into tryptic soy broth or Lactobacilli MRS broth containing 1% of NP-free solution, 0, 12, 16, 20 mM of ZnO NPs or 0, 1.8, 2.7, 4.6 mM Ag NPs, and incubated at 37 °C for 24 h. The presence and characterization of the NPs on bacterial cells were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDS). Membrane leakage and cell viability were assessed using a UV-visible spectrophotometer and confocal electron microscope, respectively. Numbers of treated cells were within 1 log CFU/mL less than those of the controls for up to 12 h of incubation. Cellular morphological changes were observed, but many cells remained in normal shapes. Only a small amount of internal cellular contents was leaked due to the NP treatments, and more live than dead cells were observed after exposure to the NPs. Based on these results, we conclude that ZnO and Ag NPs have mild inhibitory effects on intestinal bacteria.

scholarly journals Effect of captopril on post-infarction remodelling visualized by light sheet microscopy and echocardiography

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Urmas Roostalu ◽  
Louise Thisted ◽  
Jacob Lercke Skytte ◽  
Casper Gravesen Salinas ◽  
Philip Juhl Pedersen ◽  
...  
Keyword(s):  
Morphological Changes ◽  
Light Sheet ◽  
Automated Image Analysis ◽  
Border Zone ◽  
Vascular Density ◽  
Mouse Heart ◽  
Imaging Method ◽  
Light Sheet Microscopy ◽  
Post Surgery ◽  
Captopril Treatment

AbstractAngiotensin converting enzyme inhibitors, among them captopril, improve survival following myocardial infarction (MI). The mechanisms of captopril action remain inadequately understood due to its diverse effects on multiple signalling pathways at different time periods following MI. Here we aimed to establish the role of captopril in late-stage post-MI remodelling. Left anterior descending artery (LAD) ligation or sham surgery was carried out in male C57BL/6J mice. Seven days post-surgery LAD ligated mice were allocated to daily vehicle or captopril treatment continued over four weeks. To provide comprehensive characterization of the changes in mouse heart following MI a 3D light sheet imaging method was established together with automated image analysis workflow. The combination of echocardiography and light sheet imaging enabled to assess cardiac function and the underlying morphological changes. We show that delayed captopril treatment does not affect infarct size but prevents left ventricle dilation and hypertrophy, resulting in improved ejection fraction. Quantification of lectin perfused blood vessels showed improved vascular density in the infarct border zone in captopril treated mice in comparison to vehicle dosed control mice. These results validate the applicability of combined echocardiographic and light sheet assessment of drug mode of action in preclinical cardiovascular research.

scholarly journals Stochasticity in Colonial Growth Dynamics of Individual Bacterial Cells

2013 ◽  
Vol 79 (7) ◽  
pp. 2294-2301 ◽  
Author(s):  
Konstantinos P. Koutsoumanis ◽  
Alexandra Lianou
Keyword(s):  
Kinetic Parameters ◽  
Single Cells ◽  
Growth Curves ◽  
Growth Dynamics ◽  
Time Lapse ◽  
Initial Population ◽  
Bacterial Cells ◽  
Stochastic Growth ◽  
Bacterial Populations ◽  
Content Type

ABSTRACTConventional bacterial growth studies rely on large bacterial populations without considering the individual cells. Individual cells, however, can exhibit marked behavioral heterogeneity. Here, we present experimental observations on the colonial growth of 220 individual cells ofSalmonella entericaserotype Typhimurium using time-lapse microscopy videos. We found a highly heterogeneous behavior. Some cells did not grow, showing filamentation or lysis before division. Cells that were able to grow and form microcolonies showed highly diverse growth dynamics. The quality of the videos allowed for counting the cells over time and estimating the kinetic parameters lag time (λ) and maximum specific growth rate (μmax) for each microcolony originating from a single cell. To interpret the observations, the variability of the kinetic parameters was characterized using appropriate probability distributions and introduced to a stochastic model that allows for taking into account heterogeneity using Monte Carlo simulation. The model provides stochastic growth curves demonstrating that growth of single cells or small microbial populations is a pool of events each one of which has its own probability to occur. Simulations of the model illustrated how the apparent variability in population growth gradually decreases with increasing initial population size (N0). For bacterial populations withN0of >100 cells, the variability is almost eliminated and the system seems to behave deterministically, even though the underlying law is stochastic. We also used the model to demonstrate the effect of the presence and extent of a nongrowing population fraction on the stochastic growth of bacterial populations.

CLASSIFICFTION AND MECHANISM OF ACROMIAL-CLAVICULAR JOINT DAMAGE

Vestnik ◽  
2021 ◽  
pp. 147-154
Author(s):  
Е.Н. Набиев ◽  
Ж.Т. Баубеков ◽  
Е.М. Абилда ◽  
М.К. Халходжаев ◽  
Д.М. Тусупов ◽  
...  
Keyword(s):  
Acromioclavicular Joint ◽  
Morphological Changes ◽  
Joint Damage ◽  
Shoulder Girdle ◽  
Rational Treatment ◽  
Degree Of Damage

В статье приведены современные классификации повреждений акромиально-ключичного сочленения, а также механизм их возникновения. Современные классификации должны учитывать степень повреждения связочного аппарата, вид смещения ключицы и морфологические изменения, происходящие в окружающих тканях АКС и плечевого пояса. Показаны значения классификации повреждений при выборе рационального лечения повреждений акромиально-ключичного сочленения. Знание механизма повреждения позволяет специалисту прогнозировать характер и тяжесть повреждения структур сустава. Отмечено важность характера травмирующей силы при повреждении акромиально-ключичного сочленения. The article presents modern classifications of injuries of the acromioclavicular joint, as well as the mechanism of their occurrence. Modern classifications should take into account the degree of damage to the ligamentous apparatus, the type of displacement of the clavicle and morphological changes occurring in the surrounding tissues of the ACS and the shoulder girdle. The values of the classification of injuries are shown when choosing a rational treatment for injuries of the acromioclavicular joint. Knowledge of the mechanism of damage allows the specialist to predict the nature and severity of damage to the structures of the joint. The importance of the nature of the traumatic force in case of damage to the acromioclavicular joint is noted.

scholarly journals A histochemical approach to the mechanism of action of cisplatin and its analogues.

1993 ◽  
Vol 41 (7) ◽  
pp. 1053-1073 ◽  
Author(s):  
S K Aggarwal
Keyword(s):  
Membrane Transport ◽  
Mechanism Of Action ◽  
Morphological Changes ◽  
Calcium Supplementation ◽  
Rat Kidney ◽  
Light And Electron Microscopy ◽  
Atp Synthesis ◽  
Chloride Ion ◽  
Tissue Homogenates ◽  
Cancer Agent

The effects of cisplatin (CDDP), a potent anti-cancer agent, and its various analogues were analyzed for any biochemical changes involving Ca2+ and lysosomal and membrane-associated transport enzymes in rat kidney, liver, serum, urine, tissue homogenates, and isolated mitochondria. Correlation was made with any morphological changes observed by light and electron microscopy to gain an insight into the mechanism of action of various platinum coordination complexes. CDDP in its hydrolyzed state under conditions of low chloride ion concentrations causes uncoupling of oxidative phosphorylation, calcium efflux from the mitochondria, inhibits ATP synthesis, lowers membrane-associated calcium and various membrane transport enzymes, and induces an increase in the number of lysosomes. Enzymes such as alkaline phosphatase are stripped from the brush borders of the proximal tubule cells and are discharged in the urine. However, daily IV injections of calcium (1.1 ml of 1.3% CaCl2) supplementation protect the membrane-associated enzymes from cisplatin action. Carboplatin (CBDCA), an analogue of CDDP and the least nephrotoxic of all its analogues, shows little effect on the membrane-associated transport enzymes. Therefore, cisplatin and its various analogues seem to affect the membrane transport enzymes to varying degrees with related nephrotoxicity. Calcium supplementation seems to protect these enzymes and preserve kidney function.

scholarly journals Detection & Classification of Cardiac Arrhythmia

2017 ◽  
Vol 6 (1) ◽  
pp. 31
Author(s):  
Chetan M. Jadhav ◽  
V. K. Bairagi
Keyword(s):  
Cardiac Arrhythmia ◽  
Early Stage ◽  
Low Cost ◽  
Simple Method ◽  
Arrhythmia Detection ◽  
Ecg Signals ◽  
Electrocardiogram Signals ◽  
Electrical Impulses ◽  
Very High

<p>The term Arrhythmia refers to any change from the normal sequence in the electrical impulses. It is also treated as abnormal heart rhythms or irregular heartbeats. The rate of growth of Cardiac Arrhythmia disease is very high &amp; its effects can be observed in any age group in society. Arrhythmia detection can be done in many ways but effective &amp; simple method for detection &amp; diagnosis of  Cardiac Arrhythmia is by doing analysis of Electrocardiogram signals from ECG sensors. ECG signal can give us the detail information of heart activities, so we can use ECG signals to detect the rhythm &amp; behaviour of heart beats resulting into detection &amp; diagnosis of Cardiac Arrhythmia. In this paper new &amp; improved methodology for early Detection &amp; Classification of Cardiac Arrhythmia has been proposed. In this paper ECG signals are captured using ECG sensors &amp; this ECG signals are used &amp; processed to get the required data regarding heart beats of the human being &amp; then proposed methodology applies for Detection &amp; Classification of Cardiac Arrhythmia. Detection of Cardiac Arrhythmia using ECG signals allows us for easy &amp; reliable way with low cost solution to diagnose Arrhythmia in its prior early stage.</p>

Development of a High-Content Screening Assay Panel to Accelerate Mechanism of Action Studies for Oncology Research

2012 ◽  
Vol 17 (8) ◽  
pp. 1005-1017 ◽  
Author(s):  
Danli L. Towne ◽  
Emily E. Nicholl ◽  
Kenneth M. Comess ◽  
Scott C. Galasinski ◽  
Philip J. Hajduk ◽  
...  
Keyword(s):  
Drug Discovery ◽  
Mechanism Of Action ◽  
Large Scale ◽  
Morphological Changes ◽  
Single Cells ◽  
High Content Screening ◽  
Individual Compound ◽  
Screening Assay ◽  
Oncology Research ◽  
Protein Functions

Efficient elucidation of the biological mechanism of action of novel compounds remains a major bottleneck in the drug discovery process. To address this need in the area of oncology, we report the development of a multiparametric high-content screening assay panel at the level of single cells to dramatically accelerate understanding the mechanism of action of cell growth–inhibiting compounds on a large scale. Our approach is based on measuring 10 established end points associated with mitochondrial apoptosis, cell cycle disruption, DNA damage, and cellular morphological changes in the same experiment, across three multiparametric assays. The data from all of the measurements taken together are expected to help increase our current understanding of target protein functions, constrain the list of possible targets for compounds identified using phenotypic screens, and identify off-target effects. We have also developed novel data visualization and phenotypic classification approaches for detailed interpretation of individual compound effects and navigation of large collections of multiparametric cellular responses. We expect this general approach to be valuable for drug discovery across multiple therapeutic areas.

Classification of El Niño and La Niña years for water resources management in Alberta

2018 ◽  
Vol 45 (12) ◽  
pp. 1093-1098
Author(s):  
Zahidul Islam
Keyword(s):  
Water Resources ◽  
Water Resources Management ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
La Niña ◽  
Simple Method ◽  
Resources Management ◽  
La Nina

Classification of El Niño and La Niña years in a historical time period is necessary to analyze their impacts on hydrology and water resources management. In this study, various El Niño-Southern Oscillation (ENSO) indices, and how they are used to classify El Niño or La Niña years have been reviewed. Based on the review, a simple method of classifying El Niño or La Niña years has been proposed.

scholarly journals Classification of Pneumonia Cell Images Using Improved ResNet50 Model

2021 ◽  
Vol 38 (1) ◽  
pp. 165-173
Author(s):  
Ahmet Çınar ◽  
Muhammed Yıldırım ◽  
Yeşim Eroğlu
Keyword(s):  
Error Rates ◽  
Lung Imaging ◽  
Imaging Method ◽  
Data Sets ◽  
Accuracy Rate ◽  
Traditional Methods ◽  
X Ray ◽  
Qualified Personnel ◽  
Patient Will

Pneumonia is a disease caused by inflammation of the lung tissue that is transmitted by various means, primarily bacteria. Early and accurate diagnosis is important in reducing the morbidity and mortality of the disease. The primary imaging method used for the diagnosis of pneumonia is lung x-ray. While typical imaging findings of pneumonia may be present on lung imaging, nonspecific images may be present. In addition, many health units may not have qualified personnel to perform this procedure or there may be errors in diagnoses made by traditional methods. For this reason, computer systems can be used to prevent error rates that may occur in traditional methods. Many methods have been developed to train data sets. In this article, a new model has been developed based on the layers of the ResNet50. The developed model was compared with the architectures InceptionV3, AlexNet, GoogleNet, ResNet50 and DenseNet201. In the developed model, the maximum accuracy rate was achieved as 97.22%. The model developed was followed by DenseNet201, ResNet50, InceptionV3, GoogleNet and AlexNet, respectively, according to their accuracy. With these developed models, the diagnosis of pneumonia can be made early and accurately, and the treatment management of the patient will be determined quickly.

Sign in / Sign up

Export Citation Format

Share Document