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

View Article: PubMed Central - PubMed

ABSTRACT

It is crucial to develop new antischistosomal drugs since there is no vaccine and the whole world is relying on only a single drug for the treatment of schistosomiasis. One of the obstacles to the development of drugs is the absence of the high throughput objective screening methods to assess drug compounds efficacy. Thus for identification of new drug compounds candidates, fast and accurate in vitro assays are unavoidable and more research efforts in the field of drug discovery can target schistosomula. This review presents a substantial overview of the present state of in vitro drug sensitivity assays developed so far for the determination of anti-schistosomula activity of drug compounds, natural products and derivatives using newly transformed schistosomula (NTS). It highlights some of the challenges involved in in vitro compound screening using NTS and the way forward.

No MeSH data available.


Survival time of S. haematobium NTS in different culture media (Source: [26])
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Fig3: Survival time of S. haematobium NTS in different culture media (Source: [26])

Mentions: Cultivation of parasites has immense usefulness in the production of vaccines, testing efficacy of vaccine, and production of antigens for obtaining serological reagents, detection of drug-resistance, screening of potential therapeutic agents and conducting epidemiological studies. Parasite cultivation is always a challenge. In the case of schistosoma, transformed schistosomula can be grown and maintained in vitro in a complex medium [35]. The growing rate of schistosomules cultured in vitro is not the same as those in a permissive host, nor will they become patent adults. Using good and appropriate methods, about 50% of the cultured parasites will mature with fully formed guts, and 10% will develop into sexually distinct male and female worms [31]. Starting with good number of parasites, a good amount of worms can be easily maintained and provide a vast quantity of parasite material for assay. There is also a possibility to increase the percentage of schistosomules forming guts and growing properly (50% versus 20%). This can be achieved by supplementing the growth media with conditioned media during the first week of culture [31]. Using the method described by Tucker et al. [31] with supplemented DMEM or RPMI1640 media, Schistosoma spp. schistosomules can be grown in culture media for at least two months. Abdulla et al. [18] noted that the Basch Medium 169 is chosen over RPMI for schistosomula culture since worms survive more in the Bash Medium with 10% mortality for up to 4 weeks whereas in RPMI medium, an average of 40 to 60% of the parasites die within 3 days with continued mortality up to two weeks . Keiser in 2010 reported that schistosmula can survive for at least 96 h in different culture media such as MEM, DMEM, Basch, or TC 199 [19]. Marxer et al. [26] showed that supplemented Medium 199 is most suitable for the incubation of schistosomula obtained by transformation in supplemented HBSS. After undertaken comparison study on three culture media (DMEM, Medium 199, Basch medium), they reported that in the supplemented Medium 199, the parasites were still alive after 120 h with an average viability value of 2.5 while all schistosomula died by 72 h in Basch medium and by 144 h in DMEM on the other hand as shown in Fig. 3 [26]. Schistosomules are cultured at 37 °C in a 5% CO2 incubator [12, 17, 20, 23, 25–27, 31, 34, 37, 43, 45, 54]. It was also shown that over the course of one week’s incubation, parasites in Basch Medium 169 appear robust and uniform in shape and appearance. The effects of culture media on the growth of schistosomula are summarized in Table 2.Fig. 3


Mechanically produced schistosomula as a higher-throughput tools for phenotypic pre-screening in drug sensitivity assays: current research and future trends
Survival time of S. haematobium NTS in different culture media (Source: [26])
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC5120492&req=5

Fig3: Survival time of S. haematobium NTS in different culture media (Source: [26])
Mentions: Cultivation of parasites has immense usefulness in the production of vaccines, testing efficacy of vaccine, and production of antigens for obtaining serological reagents, detection of drug-resistance, screening of potential therapeutic agents and conducting epidemiological studies. Parasite cultivation is always a challenge. In the case of schistosoma, transformed schistosomula can be grown and maintained in vitro in a complex medium [35]. The growing rate of schistosomules cultured in vitro is not the same as those in a permissive host, nor will they become patent adults. Using good and appropriate methods, about 50% of the cultured parasites will mature with fully formed guts, and 10% will develop into sexually distinct male and female worms [31]. Starting with good number of parasites, a good amount of worms can be easily maintained and provide a vast quantity of parasite material for assay. There is also a possibility to increase the percentage of schistosomules forming guts and growing properly (50% versus 20%). This can be achieved by supplementing the growth media with conditioned media during the first week of culture [31]. Using the method described by Tucker et al. [31] with supplemented DMEM or RPMI1640 media, Schistosoma spp. schistosomules can be grown in culture media for at least two months. Abdulla et al. [18] noted that the Basch Medium 169 is chosen over RPMI for schistosomula culture since worms survive more in the Bash Medium with 10% mortality for up to 4 weeks whereas in RPMI medium, an average of 40 to 60% of the parasites die within 3 days with continued mortality up to two weeks . Keiser in 2010 reported that schistosmula can survive for at least 96 h in different culture media such as MEM, DMEM, Basch, or TC 199 [19]. Marxer et al. [26] showed that supplemented Medium 199 is most suitable for the incubation of schistosomula obtained by transformation in supplemented HBSS. After undertaken comparison study on three culture media (DMEM, Medium 199, Basch medium), they reported that in the supplemented Medium 199, the parasites were still alive after 120 h with an average viability value of 2.5 while all schistosomula died by 72 h in Basch medium and by 144 h in DMEM on the other hand as shown in Fig. 3 [26]. Schistosomules are cultured at 37 °C in a 5% CO2 incubator [12, 17, 20, 23, 25–27, 31, 34, 37, 43, 45, 54]. It was also shown that over the course of one week’s incubation, parasites in Basch Medium 169 appear robust and uniform in shape and appearance. The effects of culture media on the growth of schistosomula are summarized in Table 2.Fig. 3

View Article: PubMed Central - PubMed

ABSTRACT

It is crucial to develop new antischistosomal drugs since there is no vaccine and the whole world is relying on only a single drug for the treatment of schistosomiasis. One of the obstacles to the development of drugs is the absence of the high throughput objective screening methods to assess drug compounds efficacy. Thus for identification of new drug compounds candidates, fast and accurate in vitro assays are unavoidable and more research efforts in the field of drug discovery can target schistosomula. This review presents a substantial overview of the present state of in vitro drug sensitivity assays developed so far for the determination of anti-schistosomula activity of drug compounds, natural products and derivatives using newly transformed schistosomula (NTS). It highlights some of the challenges involved in in vitro compound screening using NTS and the way forward.

No MeSH data available.