Displaying publications 21 - 40 of 42 in total

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  1. Fulltext Metronidazole conjugated magnetic nanoparticles loaded with amphotericin B exhibited potent effects against pathogenic Acanthamoeba castellanii belonging to the T4 genotype
    Abdelnasir S, Anwar A, Kawish M, Anwar A, Shah MR, Siddiqui R, et al.
    AMB Express, 2020 Jul 17;10(1):127.
    PMID: 32681358 DOI: 10.1186/s13568-020-01061-z
    Acanthamoeba castellanii can cause granulomatous amoebic encephalitis and Acanthamoeba keratitis. Currently, no single drug has been developed to effectively treat infections caused by Acanthamoeba. Recent studies have shown that drugs conjugated with nanoparticles exhibit potent in vitro antiamoebic activity against pathogenic free-living amoebae. In this study, we have developed a nano drug delivery system based on iron oxide nanoparticles conjugated with metronidazole which were further loaded with amphotericin B to produce enhanced antiamoebic effects against Acanthamoeba castellanii. The results showed that metronidazole-nanoparticles-amphotericin B (Met-MNPs-Amp) significantly inhibited the viability of these amoebae as compared to the respective controls including drugs and nanoparticles alone. Met-MNPs-Amp exhibited IC50 at 50 μg/mL against both A. castellanii trophozoites and cysts. Furthermore, these nanoparticles did not affect the viability of rat and human cells and showed safe hemolytic activity. Hence, the results obtained in this study have potential utility in drug development against infections caused by Acanthamoeba castellanii. A combination of drugs can lead to successful prognosis against these largely neglected infections. Future studies will determine the value of conjugating molecules with diagnostic and therapeutic potential to provide theranostic approaches against these serious infections.
    Matched MeSH terms: Trophozoites
  2. Fulltext False positive blood culture from automated microbial detection system in severe malaria – a case report
    Syarifah Mohd Rahim, Siti Norbaya Masri, Rosni Ibrahim
    Malaysian Journal of Medicine and Health Sciences, 2020;16(1):342-344.
    MyJurnal
    Automated microbial detection system (AMDs) are design to detect early growth of bacterial and fungal. We herein report a rare case of false positive blood culture by AMDs in Plasmodium falciparum infection. A 41-year-old pre- viously healthy lady, with recent history of travelling to Lagos, Nigeria had presented to the casualty with history of fever and lethargy for three days. There was no malaria prophylaxis taken prior to the travelling history. Peripheral blood smear confirmed the presence of young trophozoite of Plasmodium falciparum with parasitemia of 7%. Con- current blood culture sent was positive, however all subcultures were negative for any growth. She was treated with intravenous artesunate however succumbed to death on the day of admission due to severe falciparum infection complicated with multiorgan failure and shock. The aim of this report is to highlight, the circumstances that can trigger the false positive AMDs detection and the possible underlying mechanism.
    Matched MeSH terms: Trophozoites
  3. Fulltext Data on antiplasmodial and stage-specific inhibitory effects of Aromatic (Ar)-Turmerone against Plasmodium falciparum 3D7
    Ali AH, Agustar HK, Hassan NI, Latip J, Embi N, Sidek HM
    Data Brief, 2020 Dec;33:106592.
    PMID: 33318979 DOI: 10.1016/j.dib.2020.106592
    Aromatic (ar)-turmerone is one of the aromatic constituents abundant in turmeric essential oil from Curcuma longa. Ar-turmerone exhibited anti-inflammatory properties. So far, antiplasmodial data for ar-turmerone is still not reported. The data showed the in vitro antiplasmodial effect of ar-turmerone against Plasmodium falciparum 3D7 (chloroquine-sensitive) via Plasmodium lactate dehydrogenase assay (pLDH) and cytotoxic effect against Vero mammalian kidney cells using 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) colourimetric assay. Selectivity indexes of ar-turmerone were calculated based on inhibition concentration at 50% of parasite growth (IC50) from MTT and pLDH assays and the effects of ar-turmerone were compared to the antimalarial reference drug chloroquine diphosphate. The inhibitory effect of ar-turmerone at the intraerythrocytic stages of plasmodial lifecycles was evaluated via a stage-dependant susceptibility test. The antiplasmodial and cytotoxic activities of ar-turmerone revealed IC50 values of 46.8 ± 2.4 μM and 820.4 ± 1.5 μM respectively. The selectivity index of ar-turmerone was 17.5. Ar-turmerone suppressed the ring-trophozoite transition stage of the intraerythrocytic life cycle of P. falciparum 3D7.
    Matched MeSH terms: Trophozoites
  4. Fulltext In vitro effects of multi-purpose contact lens disinfecting solutions towards survivability of Acanthamoeba genotype T4 in Malaysia
    Mohd Hussain RH, Afiqah WN, Abdul Ghani MK, Khan NA, Siddiqui R, Anuar TS
    Saudi J Biol Sci, 2021 Apr;28(4):2352-2359.
    PMID: 33911949 DOI: 10.1016/j.sjbs.2021.01.030
    The incidence of Acanthamoeba keratitis has been increasing since the previous decades, especially among contact lens users. This infection is majorly caused by the use of ineffective contact lens disinfecting solution. Thus, this study was conducted to evaluate the in vitro effects of multi-purpose disinfecting solutions (MPDS) against Acanthamoeba trophozoites and cysts. Acanthamoeba genotype T4 isolated from contact lens paraphernalia and an environmental strains were propagated for trophozoite or cyst-containing culture and adjusted in final concentration of 1 × 105 cells/ml. Amoebicidal and cysticidal assays were conducted by incubating trophozoites and cysts with OPTI-FREE® Express®, ReNu® Fresh™, Complete® Multi-Purpose Solution and AVIZOR Unica® Sensitive according to the manufacturer's minimum recommended disinfectant time (MMRDT) for up to 12 h at 30 ⁰C. Trypan blue hemocytometer-based microscopic counts determined amoebicidal and cysticidal effects. The viability of Acanthamoeba trophozoites and cysts was confirmed by re-inoculated them in the 1.5% non-nutrient agar plates. It was found that none of the MPDS showed amoebicidal and cysticidal effects during the MMRDT. However, OPTI-FREE® Express® demonstrated a significant differences in average cell reduction for both stages within MMRDT. When subjected to 12 h exposure, both OPTI-FREE® Express® and ReNu® Fresh™ led to significant reduction in the number of trophozoite and cyst cells. Notably, Complete® Multi-Purpose Solution and AVIZOR Unica® Sensitive did appreciably improve the solution effectiveness towards trophozoite cells when incubated for 12 h. All MPDS were largely ineffective, with 100% survival of all isolates at MMRDT, while OPTI-FREE® Express® showed limited amoebicidal activity against the contact lens paraphernalia isolate, however, it was more against the environmental strains after 12 h incubation time. The commercially available MPDS employed in this research offered minimal effectiveness against the protozoa despite the contact time. Improvement or development of new solution should consider the adjustment of the appropriate disinfectant concentration, adequate exposure time or the incorporation of novel chemical elements, which are effective against Acanthamoeba for accelerated disinfecting and more reduction of potential exposure of contact lens users to Acanthamoeba keratitis.
    Matched MeSH terms: Trophozoites
  5. [Diagnosis and Treatment of the First Imported Case of Plasmodium knowlesi Infection in China]
    Pan B, Pei FQ, Ruan CW, Lin RX, Cen YZ, Liu MR, et al.
    Zhongguo Ji Sheng Chong Xue Yu Ji Sheng Chong Bing Za Zhi, 2016 12;34(6):513-6.
    PMID: 30141606
    Objective: To diagnose and treat the first imported active case of Plasmodium knowlesi infection in China.

    Methods: The clinical information of the patient was collected. Microscopy of blood smear was conducted after Giemsa staining. Genomic DNA was extracted from blood, and PCR was conducted to amplify rDNA. The PCR products were sequenced and analyzed with BLAST

    Results: The patient returned from a one-week tour in a tropical rain forest in Malaysia. The first disease attack occurred in Guangzhou on Oct. 16, 2014, with fever, shivering and sweating. The patient was initially diagnosed as malaria and hospitalized on Oct. 26, 2014. Microscopic observation revealed typical forms of P. knowlesi in blood smear. The red blood cells became enlarged, with big trophozoites appearing as a ring with dual cores and dark brown malaria pigment. The trophozoites were slightly bigger and thicker than P. falciparum. The schizont had 6-8 merozoites, with obvious brown malaria pigment. PCR resulted in a specific band of 1 099 bp. BLAST analysis showed that the sequence of the PCR product was 99% homologous to P. knowlesi (acession No. AM910985.1, L07560.1 and AY580317.1). The patient was diagnosed as P. knowlesi infection, and was then given an 8-day treatment with chloroquine and primaquine, together with dihydroartemisinin piperaquine phosphate tablet. The patient was discharged after recovery on Oct. 28, 2014.

    Conclusion: According to the clinical symptoms, epidemiological history and laboratory test, the patient has been confirmed as P. knowlesi infection. It may also be the first active case of knowlesi malaria reported in China.

    Matched MeSH terms: Trophozoites
  6. Fulltext Sensitivity of Acanthamoeba cyst to antimicrobial agents
    Noradilah, S. A., Mohamed Kamel, A. G., Anisah, N., Noraina, A. R., Yusof, S.
    Malaysian Journal of Medicine and Health Sciences, 2010;6(1):111-117.
    MyJurnal
    Introduction: Acanthamoeba is an ubiquitous free-living protozoa which causes serious ocular problems. Acanthamoeba keratitis is becoming more prevalent amongst contact lens wearers. The disease can cause loss of vision and blindness if not treated properly. The objective of this research is to study the sensitivity of six Acanthamoeba spp. isolates, of which three were from the clinical isolates (HKL 95, HTH 40 and HS 6) and the remaining three from environmental isolates (TTT 9, TL 3 and SMAL 8) to antimicrobial agents. Methods: The antimicrobial agents chosen for this purpose were polyhexamethylene biguanide (PHMB) and chlorhexidine. Serial dilutions were perfomed for polyhexamethylene biguanide and chlorhexidine. Cyst suspensions from the chosen isolates were exposed to PHMB and chlorhexidine respectively. After 48 hours incubation time at 30°C, each mixture was filtered and filtration membrane was put onto non-nutrient agar laid with Escherichia coli. The agar plates were incubated for three days at 30°C and examined daily until day 14 to detect the presence of Acanthamoeba trophozoites under the inverted microscope. The presence of trophozoites indicated the ineffectiveness of the antimicrobial agents. Results: Both of the antimicrobial agents tested were found to be effective against Acanthamoeba cysts from all the test strains. Polyhexamethylene biguanide gave a minimum cysticidal concentration (MCC) mean value of 2.848 μg/mL while chlorhexidine showed
    MCC mean value at a concentration of 3.988 μg/mL. Conlusion: It can be concluded that the Acanthamoeba cysts were sensitive to polyhexamethylene biguanide and chlorhexidine.
    Matched MeSH terms: Trophozoites
  7. Fulltext The effectiveness of gentamicin against acanthamoeba cysts in vitro
    Noradilah, S.A., Mohamd Kamel, A.G., Anisah, N., Noraina, A.R., Yusof, S.
    Malaysian Journal of Medicine and Health Sciences, 2012;8(2):51-54.
    MyJurnal
    Acanthamoeba is a free-living protozoa which causes serious ocular problem. Acanthamoeba keratitis is becoming more prevalent amongst contact lens wearers and it can cause loss of vision and blindness if not treated properly. The objective of this research is to determine the effectiveness of gentamicin against six Acanthamoeba spp. isolates, of which three were clinical isolates (HS 6, HKL 95, HTH 73) and three environmental isolates (SMAL 7, SMAL 8, TTT 9). Cyst suspension from the chosen isolates were exposed to gentamicin. After 48 hours of incubation at temperature of 30°C and 37oC, each mixture was filtered and filtration membrane was put onto non-nutrient agar laid with Escherichia coli. The agar plates were incubated for three days at 30oC and 37oC and the plates were examined daily until day 14 to look for the presence of Acanthamoeba trophozoites under inverted microscope. The presence of trophozoites indicated the ineffectiveness of gentamicin. Gentamicin was found to be effective against Acanthamoeba cysts from all the test strains at both incubation temperatures. The minimum cysticidal concentration (MCC) mean value of gentamicin was 0.193 mg/mL at 30oC and 0.229 mg/mL at 37oC. So, we concluded that gentamicin has cysticidal potential towards Acanthamoeba.
    Matched MeSH terms: Trophozoites
  8. Fulltext Survivability of Acanthamoeba strains isolated from clinical and environmental specimens during axenization
    Nurul Farhana Jufri, Anisah Nordin, Mohamed Kamel Abd Ghani, Yusof Suboh, Noraina Abd Rahim
    Jurnal Sains Kesihatan Malaysia, 2011;9(1):1-3.
    MyJurnal
    Acanthamoeba is a free living protozoa that can cause keratitis and granulomatous amoebic encephalitis. Physiological characteristics of this amoeba are found to have a medical importance in which it can be related to the pathogenicity potential of the organism. This study was carried out to investigate the physiological characteristics of survivability during axenization. Six Acanthamoeba strains from three clinical isolates (HSB 1, HKL 48 and HKL 95) and three environmental isolates (PHS 2, PHS 11 and PHS 15) were used in this study. Axenization test was done by treating cysts with hydrochloric acid (3%) and Page saline containing Gentamicin (100 µg/ml). Cysts were then cultured into PYG enrich media, incubated at 30oC and the presence and proliferation of trophozoites of Acanthamoeba were observed. This study showed that PHS 15, HSB 1, HKL 48 and HKL 95 could be axenized but they have poor proliferation rate in PYG enrich media. The result showed that the difference between both clinical and environmental isolates was observed in two strains; PHS 2 and PHS 11. This indicates that there is a possibility that the physiological traits of strains from both isolates are the same and strains from the environment are able to show the pathogenic potential and capable of causing infection to human.
    Matched MeSH terms: Trophozoites
  9. Fulltext Ability of Acanthamoeba cyst to excyst at different temperatures
    Nurul Fariza Rossle, Mohamed Kamel Abd Ghani, Anisah Nordin, Yusof Suboh, Noraina Ab Rahim
    Jurnal Sains Kesihatan Malaysia, 2011;9(1):41-43.
    MyJurnal
    This study was carried out to observe thermotolerance ability of Acanthamoeba spp. A total of 32 Acanthamoeba spp. isolates obtained from water taps, sinks, swimming pools and sea water were used. Trophozoites of Acanthamoeba spp. were inoculated onto non-nutrient agar (NNA) seeded with heat-killed Escherichia coli using aseptic technique and incubated for 14 days at 30°C to obtain the cyst. The cysts were subcultured onto new agar plates for thermotolerance test at 37°C and 42°C. The plates were observed until 96 hours after incubation for excystation of Acanthamoeba before being declared negative. Overall, 81.25% of samples were able to excyst at 37°C while 37.5% were able to excyst at 42°C. Thermotolerant Acanthamoeba is associated with high pathogenicity potential.
    Matched MeSH terms: Trophozoites
  10. A colonic amoebic abscess mimicking colonic carcinoma
    Tan LP, Foong KK, Yvonne Ai LL
    Med J Malaysia, 2018 10;73(5):334-335.
    PMID: 30350818 MyJurnal
    Amebiasis is one of the major causes of diarrhea in the developing countries and it can present with a wide range of gastrointestinal symptoms depending on the phase of infection. We described a case of 50 year-old male patient who presented with abdominal pain, diarrhea and vomiting. After right hemicolectomy for appendicular abscess with tumour over the ileum, histopathological examinations revealed numerous trophozoites of Entamoeba histolytica in a background of inflammations (Figure 1). Following resection of the ameboma, he received intravenous metronidazole treatment for total of two weeks duration.
    Matched MeSH terms: Trophozoites
  11. Fulltext Detection of Entamoeba histolytica in experimentally induced amoebic liver abscess: comparison of three staining methods
    Ning TZ, Kin WW, Mustafa S, Ahmed A, Noordin R, Cheong TG, et al.
    Asian Pac J Trop Biomed, 2012 Jan;2(1):61-5.
    PMID: 23569836 DOI: 10.1016/S2221-1691(11)60191-3
    To compare the efficacy of three different tissue stains, namely haematoxylin and eosin (H&E), periodic-acid Schiff (PAS) and immunohistochemical (IHC) stains for detection of Entamoeba histolytica (E. histolytica) trophozoites in abscessed liver tissues of hamster.
    Matched MeSH terms: Trophozoites/cytology
  12. Oleic acid-conjugated silver nanoparticles as efficient antiamoebic agent against Acanthamoeba castellanii
    Anwar A, Abdalla SAO, Aslam Z, Shah MR, Siddiqui R, Khan NA
    Parasitol Res, 2019 Jul;118(7):2295-2304.
    PMID: 31093751 DOI: 10.1007/s00436-019-06329-3
    Acanthamoeba castellanii belonging to the T4 genotype is an opportunistic pathogen which is associated with blinding eye keratitis and rare but fatal central nervous system infection. A. castellanii pose serious challenges in antimicrobial chemotherapy due to its ability to convert into resistant, hardy shell-protected cyst form that leads to infection recurrence. The fatty acid composition of A. castellanii trophozoites is known to be most abundant in oleic acid which chemically is an unsaturated cis-9-Octadecanoic acid and naturally found in animal and vegetable fats and oils. This study was designed to evaluate antiacanthamoebic effects of oleic acid against trophozoites, cysts as well as parasite-mediated host cell cytotoxicity. Moreover, oleic acid-conjugated silver nanoparticles (AgNPs) were also synthesized and tested against A. castellanii. Oleic acid-AgNPs were synthesized by chemical reduction method and characterized by ultraviolet-visible spectrophotometry, atomic force microscopy, dynamic light scattering analysis, and Fourier transform infrared spectroscopy. Viability, growth inhibition, encystation, and excystation assays were performed with 10 and 5 μM concentration of oleic acid alone and oleic acid-conjugated AgNPs. Bioassays revealed that oleic acid alone and oleic acid-conjugated AgNPs exhibited significant antiamoebic properties, whereas nanoparticle conjugation further enhanced the efficacy of oleic acid. Phenotype differentiation assays also showed significant inhibition of encystation and excystation at 5 μM. Furthermore, oleic acid and oleic acid-conjugated AgNPs also inhibited amoebae-mediated host cell cytotoxicity as determined by lactate dehydrogenase release. These findings for the first time suggest that oleic acid-conjugated AgNPs exhibit antiacanthamoebic activity that hold potential for therapeutic applications against A. castellanii.
    Matched MeSH terms: Trophozoites/drug effects
  13. Anti-amoebic activity of acyclic and cyclic-samarium complexes on Acanthamoeba
    Kusrini E, Hashim F, Gunawan C, Mann R, Azmi WNNWN, Amin NM
    Parasitol Res, 2018 May;117(5):1409-1417.
    PMID: 29532220 DOI: 10.1007/s00436-018-5814-x
    This work investigated the anti-amoebic activity of two samarium (Sm) complexes, the acyclic complex [bis(picrato)(pentaethylene glycol)samarium(III)] picrate-referred to as [Sm(Pic)2(EO5)](Pic)-and the cyclic complex [bis(picrato)(18-crown-6)samarium(III)] picrate-referred to as [Sm(Pic)2(18C6)](Pic). Both Sm complexes caused morphological transformation of the protozoa Acanthamoeba from its native trophozoite form carrying a spine-like structure called acanthopodia, to round-shaped cells with loss of the acanthopodia structure, a trademark response to environmental stress. Further investigation, however, revealed that the two forms of the Sm complexes exerted unique cytotoxicity characteristics. Firstly, the IC50 of the acyclic complex (0.7 μg/mL) was ~ 10-fold lower than IC50 of the cyclic Sm complex (6.5 μg/mL). Secondly, treatment of the Acanthamoeba with the acyclic complex caused apoptosis of the treated cells, while the treatment with the cyclic complex caused necrosis evident by the leakage of the cell membrane. Both treatments induced DNA damage in Acanthamoeba. Finally, a molecular docking simulation revealed the potential capability of the acyclic complex to form hydrogen bonds with profilin-a membrane protein present in eukaryotes, including Acanthamoeba, that plays important roles in the formation and degradation of actin cytoskeleton. Not found for the cyclic complex, such potential interactions could be the underlying reason, at least in part, for the much higher cytotoxicity of the acyclic complex and also possibly, for the observed differences in the cytotoxicity traits. Nonetheless, with IC50 values of
    Matched MeSH terms: Trophozoites/drug effects
  14. Plasmodium knowlesi: the emerging zoonotic malaria parasite
    Antinori S, Galimberti L, Milazzo L, Corbellino M
    Acta Trop, 2013 Feb;125(2):191-201.
    PMID: 23088834 DOI: 10.1016/j.actatropica.2012.10.008
    Plasmodium knowlesi was initially identified in the 30s as a natural Plasmodium of Macaca fascicularis monkey also capable of experimentally infecting humans. It gained a relative notoriety in the mid-30s as an alternative to Plasmodium vivax in the treatment of the general paralysis of the insane (neurosyphilis). In 1965 the first natural human infection was described in a US military surveyor coming back from the Pahang jungle of the Malaysian peninsula. P. knowlesi was again brought to the attention of the medical community when in 2004, Balbir Singh and his co-workers reported that about 58% of malaria cases observed in the Kapit district of the Malaysian Borneo were actually caused by P. knowlesi. In the following years several reports showed that P. knowlesi is much more widespread than initially thought with cases reported across Southeast Asia. This infection should also be considered in the differential diagnosis of any febrile travellers coming back from a recent travel to forested areas of Southeast Asia. P. knowlesi can cause severe malaria with a rate of 6-9% and with a case fatality rate of 3%. Respiratory distress, acute renal failure, shock and hyperbilirubinemia are the most frequently observed complications of severe P. knowlesi malaria. Chloroquine is considered the treatment of choice of uncomplicated malaria caused by P. knowlesi.
    Matched MeSH terms: Trophozoites/growth & development
  15. Fulltext Phosphorylated and Nonphosphorylated PfMAP2 Are Localized in the Nucleus, Dependent on the Stage of Plasmodium falciparum Asexual Maturation
    Dahalan FA, Sidek HM, Murtey MD, Embi MN, Ibrahim J, Fei Tieng L, et al.
    Biomed Res Int, 2016;2016:1645097.
    PMID: 27525262 DOI: 10.1155/2016/1645097
    Plasmodium falciparum mitogen-activated protein (MAP) kinases, a family of enzymes central to signal transduction processes including inflammatory responses, are a promising target for antimalarial drug development. Our study shows for the first time that the P. falciparum specific MAP kinase 2 (PfMAP2) is colocalized in the nucleus of all of the asexual erythrocytic stages of P. falciparum and is particularly elevated in its phosphorylated form. It was also discovered that PfMAP2 is expressed in its highest quantity during the early trophozoite (ring form) stage and significantly reduced in the mature trophozoite and schizont stages. Although the phosphorylated form of the kinase is always more prevalent, its ratio relative to the nonphosphorylated form remained constant irrespective of the parasites' developmental stage. We have also shown that the TSH motif specifically renders PfMAP2 genetically divergent from the other plasmodial MAP kinase activation sites using Neighbour Joining analysis. Furthermore, TSH motif-specific designed antibody is crucial in determining the location of the expression of the PfMAP2 protein. However, by using immunoelectron microscopy, PPfMAP2 were detected ubiquitously in the parasitized erythrocytes. In summary, PfMAP2 may play a far more important role than previously thought and is a worthy candidate for research as an antimalarial.
    Matched MeSH terms: Trophozoites/enzymology
  16. Repositioning of Guanabenz in Conjugation with Gold and Silver Nanoparticles against Pathogenic Amoebae Acanthamoeba castellanii and Naegleria fowleri
    Anwar A, Mungroo MR, Anwar A, Sullivan WJ, Khan NA, Siddiqui R
    ACS Infect Dis, 2019 Dec 13;5(12):2039-2046.
    PMID: 31612700 DOI: 10.1021/acsinfecdis.9b00263
    Brain-eating amoebae cause devastating infections in the central nervous system of humans, resulting in a mortality rate of 95%. There are limited effective therapeutic options available clinically for treating granulomatous amoebic encephalitis and primary amoebic meningoencephalitis caused by Acanthamoeba castellanii (A. castellanii) and Naegleria fowleri (N. fowleri), respectively. Here, we report for the first time that guanabenz conjugated to gold and silver nanoparticles has significant antiamoebic activity against both A. castellanii and N. fowleri. Gold and silver conjugated guanabenz nanoparticles were synthesized by the one-phase reduction method and were characterized by ultraviolet-visible spectrophotometry and atomic force microscopy. Both metals were facilely stabilized by the coating of guanabenz, which was examined by surface plasmon resonance determination. The average size of gold nanoconjugated guanabenz was found to be 60 nm, whereas silver nanoparticles were produced in a larger size distribution with the average diameter of around 100 nm. Guanabenz and its noble metal nanoconjugates exhibited potent antiamoebic effects in the range of 2.5 to 100 μM against both amoebae. Nanoparticle conjugation enhanced the antiamoebic effects of guanabenz, as more potent activity was observed at a lower effective concentration (2.5 and 5 μM) compared to the drug alone. Moreover, encystation and excystation assays revealed that guanabenz inhibits the interconversion between the trophozoite and cyst forms of A. castellanii. Cysticdal effects against N. fowleri were also observed. Notably, pretreatment of A. castellanii with guanabenz and its nanoconjugates exhibited a significant reduction in the host cell cytopathogenicity from 65% to 38% and 2% in case of gold and silver nanoconjugates, respectively. Moreover, the cytotoxic evaluation of guanabenz and its nanoconjugates revealed negligible cytotoxicity against human cells. Guanabenz is already approved for hypertension and crosses the blood-brain barrier; the results of our current study suggest that guanabenz and its conjugated gold and silver nanoparticles can be repurposed as a potential drug for treating brain-eating amoebic infections.
    Matched MeSH terms: Trophozoites/drug effects
  17. Fulltext Potential anti-Acanthamoeba and anti-adhesion activities of Annona muricata and Combretum trifoliatum extracts and their synergistic effects in combination with chlorhexidine against Acanthamoeba triangularis trophozoites and cysts
    Mitsuwan W, Sin C, Keo S, Sangkanu S, de Lourdes Pereira M, Jimoh TO, et al.
    Heliyon, 2021 May;7(5):e06976.
    PMID: 34027178 DOI: 10.1016/j.heliyon.2021.e06976
    Plants with medicinal properties have been used in the treatment of several infectious diseases, including Acanthamoeba infections. The medicinal properties of Cambodian plant extracts; Annona muricata and Combretum trifoliatum were investigated against Acanthamoeba triangularis. A total of 39 plant extracts were evaluated and, as a result, 22 extracts showed positive anti-Acanthamoeba activity. Of the 22 extracts, 9 and 4 extracts showed anti-Acanthamoeba activity against trophozoites and cysts of A. triangularis, respectively. The minimum inhibitory concentration of A. muricata and C. trifoliatum extracts against trophozoites and cysts was 500 and 1,000 μg/mL, respectively. The combination of A. muricata at 1/4×MIC with chlorhexidine at 1/8×MIC demonstrated a synergistic effect against trophozoites, but partial synergy against cysts. A 40% reduction in trophozoites and 60% of cysts adhered to the plastic surface treated with both extracts at 1/2×MIC were noted comparing to the control (P < 0.05). Furthermore, a reduction of 80% and 90% of trophozoites adhered to the surface was observed after pre-treatment with A. muricata and C. trifoliatum extracts, respectively. A 90% of cysts adhered to the surface was decreased with pre-treatment of A. muricata at 1/2×MIC (P < 0.05). A 75% of trophozoites and cysts from Acanthamoeba adhered to the surface were removed after treatment with both extracts at 4×MIC (P < 0.05). In the model of contact lens, 1 log cells/mL of trophozoites and cysts was significantly decreased post-treatment with both extracts compared to the control. Trophozoites showed strong loss of acanthopodia and thorn-like projection pseudopodia, while cysts demonstrated retraction and folded appearance treated with both extracts when observed by SEM, which suggests the potential benefits of the medicinal plants A. muricata and C. trifoliatum as an option treatment against Acanthamoeba infections.
    Matched MeSH terms: Trophozoites
  18. Fulltext Loop-mediated isothermal amplification (LAMP) reaction as viable PCR substitute for diagnostic applications: a comparative analysis study of LAMP, conventional PCR, nested PCR (nPCR) and real-time PCR (qPCR) based on Entamoeba histolytica DNA derived from faecal sample
    Foo PC, Nurul Najian AB, Muhamad NA, Ahamad M, Mohamed M, Yean Yean C, et al.
    BMC Biotechnol, 2020 Jun 22;20(1):34.
    PMID: 32571286 DOI: 10.1186/s12896-020-00629-8
    BACKGROUND: This study reports the analytical sensitivity and specificity of a Loop-mediated isothermal amplification (LAMP) and compares its amplification performance with conventional PCR, nested PCR (nPCR) and real-time PCR (qPCR). All the assays demonstrated in this study were developed based on Serine-rich Entamoeba histolytica protein (SREHP) gene as study model.

    RESULTS: A set of SREHP gene specific LAMP primers were designed for the specific detection of Entamoeba histolytica. This set of primers recorded 100% specificity when it was evaluated against 3 medically important Entamoeba species and 75 other pathogenic microorganisms. These primers were later modified for conventional PCR, nPCR and qPCR applications. Besides, 3 different post-LAMP analyses including agarose gel electrophoresis, nucleic acid lateral flow immunoassay and calcein-manganese dye techniques were used to compare their limit of detection (LoD). One E. histolytica trophozoite was recorded as the LoD for all the 3 post-LAMP analysis methods when tested with E. histolytica DNA extracted from spiked stool samples. In contrast, none of the PCR method outperformed LAMP as both qPCR and nPCR recorded LoD of 100 trophozoites while the LoD of conventional PCR was 1000 trophozoites.

    CONCLUSIONS: The analytical sensitivity comparison among the conventional PCR, nPCR, qPCR and LAMP reveals that the LAMP outperformed the others in terms of LoD and amplification time. Hence, LAMP is a relevant alternative DNA-based amplification platform for sensitive and specific detection of pathogens.

    Matched MeSH terms: Trophozoites
  19. The acetone crude extract of Quercus infectoria (Olivier) galls alters pH of the digestive vacuole of the malaria parasite, Plasmodium falciparum
    Trop Biomed, 2021 Jun 01;38(2):40-47.
    PMID: 33973571 DOI: 10.47665/tb.38.2.035
    The reduced efficacy of the mainstay antimalarial drugs due to the widespread of drugresistant Plasmodium falciparum has necessitated efforts to discover new antimalarial drugs with new targets. Quercus infectoria (Olivier) has long been used to treat various ailments including fever. The acetone extract of the plant galls has recently been reported to have a promising antimalarial activity in vitro. This study was aimed to determine the effect of the Q. infectoria gall acetone crude extract on pH of the digestive vacuole of Plasmodium falciparum. A ratiometric fluorescent probe, fluorescein isothiocyanate-dextran (FITC-dextran) was used to facilitate a quantitative measurement of the digestive vacuole pH by flow cytometry. Mid trophozoite stage malaria parasites grown in resealed erythrocytes containing FITC-dextran were treated with different concentrations of the acetone extract based on the 50% inhibitory concentration (IC50). Saponin-permeabilized parasites were analyzed to obtain the ratio of green/yellow fluorescence intensity (Rgy) plotted as a function of pH in a pH calibration curve of FITC-dextran. Based on the pH calibration curve, the pH of the digestive vacuole of the acetone extract-treated parasites was significantly altered (pH values ranged from 6.35- 6.71) in a concentration-dependent manner compared to the untreated parasites (pH = 5.32) (p < 0.001). This study provides a valuable insight into the potential of the Q. infectoria galls as a promising antimalarial candidate with a novel mechanism of action.
    Matched MeSH terms: Trophozoites
  20. Fulltext Isoniazid Conjugated Magnetic Nanoparticles Loaded with Amphotericin B as a Potent Antiamoebic Agent against Acanthamoeba castellanii
    Iqbal K, Abdalla SAO, Anwar A, Iqbal KM, Shah MR, Anwar A, et al.
    Antibiotics (Basel), 2020 May 25;9(5).
    PMID: 32466210 DOI: 10.3390/antibiotics9050276
    The pathogenic free-living amoeba, Acanthamoeba castellanii, is responsible for a rare but deadly central nervous system infection, granulomatous amoebic encephalitis and a blinding eye disease called Acanthamoeba keratitis. Currently, a combination of biguanides, amidine, azoles and antibiotics are used to manage these infections; however, the host cell cytotoxicity of these drugs remains a challenge. Furthermore, Acanthamoeba species are capable of transforming to the cyst form to resist chemotherapy. Herein, we have developed a nano drug delivery system based on iron oxide nanoparticles conjugated with isoniazid, which were further loaded with amphotericin B (ISO-NPs-AMP) to cause potent antiamoebic effects against Acanthamoeba castellanii. The IC50 of isoniazid conjugated with magnetic nanoparticles and loaded with amphotericin B was found to be 45 μg/mL against Acanthamoeba castellanii trophozoites and 50 μg/mL against cysts. The results obtained in this study have promising implications in drug discovery as these nanomaterials exhibited high trophicidal and cysticidal effects, as well as limited cytotoxicity against rat and human cells.
    Matched MeSH terms: Trophozoites
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