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Table 4 Summary of the published studies

From: Mechanically produced schistosomula as a higher-throughput tools for phenotypic pre-screening in drug sensitivity assays: current research and future trends

Objective

Media used

NTS procedure

Outcome

Reference

Mansour et al. (2016) screened almost 300,000 compounds using an assay based on motility of worm, larvae and image analysis of assay plates

M169 supplemented with 100 U/ml Penicillin, 300 μg/ml Streptomycin, 0.25 μg/ml Fungizone (Amphotericin B) and 5 % fetal calf serum (FCS)

Mechanical transformation using the Syringe needle Method

A number of compounds were identified as promising leads for further chemical optimization

[54]

Panic et al. (2015a) investigate a panel of fluorescence/luminescence dyes for their applicability as viability markers in drug sensitivity assays for Schistosoma mansoni schistosomula

Medium 199 supplemented with 5 % heat iFCS and 1 % penicillin-streptomycin mixture

Mechanical in vitro transformation (vortexing)

Of the 11 markers selected for testing, resazurin, Vybrant® and CellTiter-Glo® correlated best with NTS viability, produced signals ≥ 3-fold stronger than background noise and revealed a significant signal-to-NTS concentration relationship

[23]

Panic et al. (2015b) expands the knowledge of antischistosomal properties of already approved 1600 FDA compounds from a very diverse set of indications against Schistosoma mansoni

Medium 199 supplemented with 5 % heat iFCS and 1 % penicillin/streptomycin

Mechanical in vitro transformation (vortexing)

Of the 1600 compounds screened against schistosomula, 121 were identified as active and 36 of these were active on the adult worms after Screening. The two in vivo- moderately active drugs identified in this study, doramectin and clofazimine present as novel drug classes as starting points for further investigation

[25]

Lalli et al. (2015) describes the development and validation of a luminescence based, medium-throughput assay for the detection of schistosomula viability through quantitation of ATP

DMEM complete tissue culture medium

Mechanical in vitro transformation (vortexing)

Schistosomula viability luminescence based assay is successful and suitable for the identification of novel compounds potentially exploitable in future schistosomiasis therapies

Thus representing a valid alternative to fluorescence-based microscopy assays

[63]

Howe et al. (2015) assessed lactate as a surrogate marker for viability in Schistosoma drug screening assays by testing compounds with reported potencies

Phenol-red free medium 199

Supplemented with 5.5 mM D-glucose, 200 U/ml penicillin, 200 μg/ml streptomycin, 1 % heat iFCS

Mechanically transformed by vortexing

Lactate levels clearly reflected the viability of schistosomula and correlated with schistosomulum numbers. Lactate is a sensitive and simple surrogate marker to be measured to determine Schistosoma viability in compound screening assays

[24]

Ingram-Sieber et al.(2014) investigated the Medicines for Malaria Venture malaria box containing 200 diverse drug-like and 200 probe-like compounds with known antimalarial activity against larval stage of S. mansoni, followed by testing against adult worms in vitro and by in vivo studies of lead candidates

Supplemented Medium 199 with 5 % heat iFCS, penicillin (100 U/ml), and streptomycin (100 μg/ml)

Mechanically transformation by vortexing

Underlined the potential of compounds with an antimalarial background on schistosomes. Two entirely new chemical scaffolds with antischistosomal in vitro activity in the sub micromolar range and moderate in vivo activity identified

[12]

Protasio et al. (2013) analyzed differences in gene expression patterns between Mechanical and Skin Transformed Schistosoma mansoni

Schistosomula and provide enough data to resolve a long-lasting controversy

Supplemented DMEM, 10 % FCS, 1 % Hepes buffer with 100 U/L penicillin, 0.1 mg/L streptomycin and 10 mM L-glutamine

- Mechanical transformation using the 21G Syringe needle method

- Excised skin from mice

This work contributes to the validation of gene expression studies that have used Mechanical transformed schistosomula and provides further evidence that the MT is a good proxy for natural skin transformation

[37]

Coultas et al. (2012) compared a current and widely used double-ended-needle mechanical transformation method to a culture medium based on a nonmechanical method

RPMI 1640 medium enriched with L-glutamine; 150 units/ml penicillin, 100 μg/ml streptomycin and 5 % heat inactivated fetal bovine serum (iFBS)

Mechanical transformation using the 22-gauge double-ended, luer lok emulsifying needle

The mechanical and nonmechanical cercariae transformation methods both yielded significantly large and similar quantities of viable schistosomula

[49]

de Moraes et al. (2012) report the in vitro antischistosomal activity of piplartine on S. mansoni schistosomula of different ages

Basch 169 medium containing antibiotics and supplemented with 10 % fetal bovine serum (FBS)

Mechanical transformation, using a Vortex mixer

This report provides the first evidence that piplartine is able to kill schistosomula of different ages and reinforce that piplartine is a promising compound that could be used for the development of new schistosomicidal agent

[36]

Marxer et al. (2012) developed an in vitro drug screening assay for S. haematobium newly transformed schistosomula (NTS). The cercarial emergence rhythms of the intermediate hosts of S. mansoni and S. haematobium, Biomphalaria glabrata and Bulinus truncatus were studied, two artificial transformation methods for the production of the schistosomula were compared and the best purification method and optimal culture conditions were established by testing three different methods and several different media

Basch Medium 169, DMEM and Medium 199. All supplemented with 5 % heat iFCS and 200 U/ml penicillin and 200 μg/ml streptomycin

Mechanical transformation, using a Vortex mixer and chemical transformation using glucose

A circadian rhythm existed in both snail species. The highest transformation rate of S. haematobium cercariae into NTS was obtained with the vortex transformation and the highest purification factor was observed using Percoll. The fluorimetric readout based on resazurin was very precise in detecting dead schistosomula

[26]

Ingram et al. (2012) tested mefloquine-related compounds belonging to the three major groups of arylmethanols in order to elucidate their potential as antischistosomal lead candidates. The selected arylmethanols were tested against S. mansoni schistosomula and adults worms in vitro

Medium 199 supplemented with 5 % heat iFCS, penicillin (100 U/ml), and streptomycin (100 μg/ml)

Mechanically transformation by vortexing

The study confirmed the high antischistosomal activity of compounds with a mefloquine scaffold. Four candidates, WR7930, its two derivatives, and enpiroline, that are characterized by high antischistosomal properties in vivo were identified

[34]

Milligan et al. (2011) provide a visual description of cercarial transformation and in vitro culturing of schistosomules

RPMI 1640 supplemented with 5 % FBS, 1X Penicillin/Streptomycin

Mechanical transformation using the 22-gauge double-ended, luer lok emulsifying needle

This study developed a visual protocols for in vitro cercarial transformation and schistosomules culture techniques

[38]

Smout et al. (2010) describe a novel application for a real-time cell monitoring device (xCELLigence) that can simply and objectively assess anthelmintic effects by measuring parasite motility in real time in a fully automated high-throughput fashion

RPMI 1640, 1 % antibiotic/antimycotic and 10 mM Hepes

-

The study reported that the technique can be suitable for discovery and development of new anthelmintic drugs as well as for detection of phenotypic resistance to existing drugs for the majority of helminths and other pathogens where motility is a measure of pathogen viability

[62]

Mansour et al.(2010) report the development and validation of the Alamar Blue assay compared with morphology-based (microscopic) assessment of compound activity

M169 supplemented with 100 U/ml Penicillin, 100 mg/ml Streptomycin and 5 % FCS

Mechanical transformation using the Syringe Method

The Alamar Blue assay is readily able to detect compounds causing death or severe damage to the larvae but is less reliable than microscopy for more subtle morphological changes. It is concluded that an automated high throughput screen would benefit from integrated use of both alamar blue and automatic image-based morphology assays

[20]

Manneck et al.(2010) studied the temporal effect of this Mefloquine in vitro and in vivo, and examined alterations on the tegumental surface of schistosomula and adults of S. mansoni by means of scanning electron microscopy (SEM)

Basch medium 169 supplemented with 5 % heat iFCS and 100 U/ml penicillin and 100 mg/ml streptomycin

Mechanically transformation by vortexing

Mefloquine induces extensive morphological and tegumental alterations on both S. mansoni schistosomula and adults in vitro and in vivo

[27]

Peak et al. (2010) presented a microtiter plate-based method for reproducibly detecting schistosomula viability that takes advantage of the differential uptake of fluorophores (propidium iodide and fluorescein diacetate) by living organisms

DMEM lacking phenol red, containing 4500 mg/l glucose, supplemented with 10 % FCS, 2 mM L-glutamine, 200 U/ml penicillin, 200 mg/ml streptomycin

Mechanically transformation by vortexing

The study showed that developed method is sensitive (200 schistosomula/well can be assayed), relevant to industrial (384-well microtiter plate compatibility) and academic (96-well microtiter plate compatibility) settings, translatable to functional genomics screens and drug assays

[17]

Abdulla et al. (2009) presented a partially automated, three component phenotypic screen workflow that utilizes at its apex the schistosomula stage of the parasite adapted to a 96-well plate format.

Hits that arise are subsequently screened in vitro against adult parasites and finally for efficacy in a murine model of disease

Basch Medium 169

Mechanical transformation using the 22-gauge double-ended, luer lok emulsifying needle

The study has identified various compounds and drugs as hits in vitro and leads, with the prescribed oral efficacy, in vivo

[18]

  1. NTS newly transformed schistosomula, DMEM Dulbecco’s modified eagle’s medium, RPMI Roswell Park Memorial Institute, iFCS heat inactivated fetal calf serum, SEM scanning electron microscopy