Circular Estimate Method (CEM) - a Simple Method to Estimate Caenorhabditis elegans Culture Densities in Liquid Medium

Josende, Marcelo Estrella; Nunes, Silvana Manske; Müller, Larissa; Ferreira-Cravo, Marlize; Monserrat, José M.; Ventura‐Lima, Juliane

doi:10.1186/s12575-018-0089-2

Cited by 18 publications

(7 citation statements)

References 34 publications

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“…The minimum biofilm eradication concentration (MBIC) is the lowest concentration of an antimicrobial substance that induces no time dependent increase in the mean number of biofilm viable cells. It is commonly used to assess the inhibitory effects of formulations on biofilms [ 67 ]. It could be useful for future studies to determine the MBIC to fully and accurately determine the effects of our formulations on P. aeruginosa biofilms.…”

Section: Discussionmentioning

confidence: 99%

The Impact of an Efflux Pump Inhibitor on the Activity of Free and Liposomal Antibiotics against Pseudomonas aeruginosa

Gbian

Omri

2021

Pharmaceutics

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The eradication of Pseudomonas aeruginosa in cystic fibrosis patients has become continuously difficult due to its increased resistance to treatments. This study assessed the efficacy of free and liposomal gentamicin and erythromycin, combined with Phenylalanine arginine beta-naphthylamide (PABN), a broad-spectrum efflux pump inhibitor, against P. aeruginosa isolates. Liposomes were prepared and characterized for their sizes and encapsulation efficiencies. The antimicrobial activities of formulations were determined by the microbroth dilution method. Their activity on P. aeruginosa biofilms was assessed, and the effect of sub-inhibitory concentrations on bacterial virulence factors, quorum sensing (QS) signals and bacterial motility was also evaluated. The average diameters of liposomes were 562.67 ± 33.74 nm for gentamicin and 3086.35 ± 553.95 nm for erythromycin, with encapsulation efficiencies of 13.89 ± 1.54% and 51.58 ± 2.84%, respectively. Liposomes and PABN combinations potentiated antibiotics by reducing minimum inhibitory and bactericidal concentrations by 4–32 fold overall. The formulations significantly inhibited biofilm formation and differentially attenuated virulence factor production as well as motility. Unexpectedly, QS signal production was not affected by treatments. Taken together, the results indicate that PABN shows potential as an adjuvant of liposomal macrolides and aminoglycosides in the management of lung infections in cystic fibrosis patients.

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Section: Discussionmentioning

confidence: 99%

The Impact of an Efflux Pump Inhibitor on the Activity of Free and Liposomal Antibiotics against Pseudomonas aeruginosa

Gbian

Omri

2021

Pharmaceutics

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“…Collection has been performed with the aim of storage samples in the “Bruno Boerci Oncological Biobank” of ICS Maugeri IRCCS. All surgical samples have been analysed by the pathologist, who has collected healthy and/or tumour tissue to be processed for PDO isolation, as previously described [ 18 ]. Healthy tissue represented normal mammary tissue collected from a mammary portion distant to cancer.…”

Section: Methodsmentioning

confidence: 99%

Ultrastructural analysis of breast cancer patient-derived organoids

et al. 2021

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Background Breast cancer Patient Derived Organoids (PDO) have been demonstrated to be a reliable model to study cancer that promised to replace and reduce the use of animals in pre-clinical research. They displayed concordance with the tissue of origin, resuming its heterogenicity and representing a good platform to develop approaches of personalized medicines. Although obtain PDOs from mammary tumour, was a very challenging process, several ongoing studies evaluated them as a platform to study efficacy, sensitivity and specificity of new drugs and exploited them in personalized medicine. Despite tissue organization represented a crucial point to evaluate in a 3-dimensional model, since it could influence drug penetration, morphology of breast cancer PDOs has not been analysed yet. Here, we proposed a complete ultrastructural analysis of breast PDOs obtained from tumour and healthy tissues to evaluate how typical structures observed in mammary gland were resumed in this model. Methods 81 samples of mammary tissue (healthy or tumour) resulting from surgical resections have been processed to obtain PDO. The resulting PDOs embedded in matrigel drop have been processed for transmission electron microscopy and analysed. A comparison between ones from healthy and ones from cancerous tissue has been performed and PDOs derived from tumour tissue have been stratified according to their histological and molecular subtype. Result The morphological analysis performed on 81 PDO revealed an organized structure rich in Golgi, secretion granules and mitochondria, which was typical of cells with a strong secretory activity and active metabolism. The presence of desmosomes, inter and intracellular lumens and of microvilli and interdigitations signified a precise tissue-organization. Each PDO has been classified based on whether or not it possessed (i) peripheral ridges in mitochondria, (ii) intracellular lumens, (iii) intercellular lumens, (iv) micro-vesicles, (v) open desmosomes, (vi) cell debris, (vii) polylobed nuclei, (viii) lysosomes and (ix) secretion granules, in order to identify features coupled with the cancerous state or with a specific histological or molecular subtype. Conclusion Here we have demonstrated the suitability of breast cancer PDO as 3-dimensional model of mammary tissue. Besides, some structural features characterizing cancerous PDO have been observed, identifying the presence of distinctive traits.

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“…The other part of the final pellet was separated into two tubes containing 1 mL of Trizol for total RNA extraction until a total of six samples per experimental group was reached. The necessary estimates to distribute the desired number of animals per each treatment in the gene expression experiment were performed according to a new method (Circular Estimate Method [CEM]), which provides an accurate and precise estimate than the traditional manual method …”

Section: Methodsmentioning

confidence: 99%

The effects of Microcystis aeruginosa cells lysate containing microcystins on physiological and molecular responses in the nematode Caenorhabditis elegans

Sopezki

Josende

Cruz

et al. 2020

Environmental Toxicology

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Microcystins (MCs) are potent toxins produced by environmental cyanobacterial blooms. The present study evaluated the effects of a Microcystis aeruginosa cyanobacterial lysate containing 0.1, 1, and 10 μg L−1 MC‐LR equivalent in the C. elegans Bristol N2 wild‐type and the effects caused by equivalent concentrations of a MC‐LR standard. The lysate was prepared from a culture of toxic strain (RST9501) originated from the Patos Lagoon Estuary (RS, Brazil). The minimal concentration necessary to cause significant effects in C. elegans under exposure to M. aeruginosa lysate or to MC‐LR standard were, respectively, 10 and 0.1 μg L−1 MC‐LR equivalent for growth and 10 and 1 μg L−1 MC‐LR equivalent for fertility. Reproduction (ie, brood size) was only affected by the exposure to 10 μg L−1 MC‐LR standard and was not affected by the lysate. The nematodes that were exposed to lysate containing 1 μg L−1 MC‐LR equivalent or MC‐LR were also analyzed for pharyngeal pumping and gene expression using RT‐qPCR. The worms’ rhythmic contractions of the pharynx were similarly affected by the lysate containing 1 μg L−1 of MC‐LR equivalent and the MC‐LR standard. The MC‐LR standard caused down‐regulation of genes related to growth (daf‐16), fertility (spe‐10), and biotransformation (gst‐2). This is the first study to evaluate the effects of a toxic cyanobacterial lysate using the C. elegans model. This study suggests the organism as a potential biotest to evaluate toxicity of natural waters containing M. aeruginosa cells and to environmental risk assessment associated to cyanobacterial bloom events.

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Circular Estimate Method (CEM) - a Simple Method to Estimate Caenorhabditis elegans Culture Densities in Liquid Medium

Cited by 18 publications

References 34 publications

The Impact of an Efflux Pump Inhibitor on the Activity of Free and Liposomal Antibiotics against Pseudomonas aeruginosa

The Impact of an Efflux Pump Inhibitor on the Activity of Free and Liposomal Antibiotics against Pseudomonas aeruginosa

Ultrastructural analysis of breast cancer patient-derived organoids

The effects of Microcystis aeruginosa cells lysate containing microcystins on physiological and molecular responses in the nematode Caenorhabditis elegans

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