Experimental parasitology最新文献

Effect of Meloidogyne incognita and Pseudomonas syringae pv. aptata (Psa) was observed singly, together and pre and post inoculations in 4 soil types on plant growth parameters, chlorophyll, carotenoid and proline contents of beetroot (Beta vulgaris L.). Plant growth, chlorophyll and carotenoid contents were greater in loam soil followed by 20% fly ash soil, 10% fly ash plus 10% sand amended soil and least in 20 % sand mix soil. However, proline contents were high in 20% sand mix soil and least in loam soil. Plant growth (root dry weight), chlorophyll and carotenoid contents were reduced in plants inoculated with any test pathogen while proline contents were increased in plants inoculated with pathogens under study. Inoculation of both pathogens together caused a greater reduction of plant growth, chlorophyll and carotenoid contents than their individual inoculation. Inoculation of M. incognita 20 days prior to Psa resulted in greatest reduction in plant growth, chlorophyll and carotenoid and maximum proline contents. Inoculation of Psa with M. incognita reduced galling and nematode multiplication while prior inoculation of Psa caused maximum reduction in galling and nematode multiplication. Galling and nematode multiplication was high in 20% sand mix soil followed by loam soil and least in 20% fly ash amended soil. Bacterial leaf spot indices by Psa was 3 when alone. Disease indices were 5 when Psa was inoculated with M. incognita. Prior inoculation of M. incognita predisposed beetroots to Psa and aggravates the disease. Influence of M. incognita, Psa and their interactions in different soil types on various studied parameters in diseased plants was demonstrated by Principal component analysis.

The protozoan parasite Leishmania has a large family of major facilitator membrane proteins part of the Folate Biopterin Transporter (FBT) family. The chromosome 10 of Leishmania has a cluster of 7 FBT genes including the S-Adenosyl methionine (AdoMet) transporter and the functionally characterized folate transporters FT1 and FT5. Six of the 7 FBT proteins coded by this locus are located at the plasma membrane as determined by gene fusions with the green fluorescent protein. We deleted the whole locus of 7 genes (>30 kb) using CRISPR-Cas9 genome editing as a first step in studying the potential function of the four uncharacterized FBT genes from the locus. This knock out strain was viable, highly resistant to sinefungin (an AdoMet analogue) and to methotrexate (a folate analogue) but not to allopurinol, pentamidine or 5-fluorouracil. We similarly studied another FBT family member whose gene is encoded on chromosome 19. The protein was also located at the plasma membrane and its gene was dispensable for growth and not associated to any of the drug tested. Our work has indicated that large diploid deletion is achievable in Leishmania and the cell lines produced here will serve to better understand the function and putative substrates of these FBT proteins yet to be characterized.

Fasciolosis is a food-borne anthropozoonotic disease caused by Fasciola spp. that affects multiple hosts, including ruminants and humans. In vitro testing of anthelmintics is of interest to establish the drug's activity without the need for time-consuming and expensive in vivo assays. This study was set to establish a discriminatory dose (DD) by running a dose-titration in vitro experiment (egg hatch test, EHT) of albendazole sulfoxide (ABZ.SO) and nitroxynil (NTX) on eggs of a field strain of Fasciola hepatica. Eggs were recovered from adult parasites isolated from intact bovine livers obtained from a single farm in Paraná, Brazil (FhPar2022 strain) with no ABZ or NTX treatment history. Two hundred eggs were exposed to 18 and 14 concentrations of ABZ.SO and NTX, respectively, for 12h and incubated for 16 days. Egg development and integrity were determined every other day, establishing an index of morphological modification of the different phases. A concentration-dependent effect was observed for egg development in both compounds. ABZ.SO solutions prevent egg hatch, except for the two lowest concentrations. We observed no egg hatch at 6.250-100.0 μmol L^-1 for NTX. NTX had an inhibition concentration of 50% (IC₅₀) of 0.043 μmol L^-1 with a correlation coefficient of (R²) 0.961. ABZ.SO had an IC₅₀ of 0.00099 μmol L^-1 with a low R² of 0.417. Morphological damage was also associated with the increasing concentration of both drugs. Moreover, it was noted that most eggs that reached the eye spot type could hatch, except at 0.39 and 3.12 μmol L^-1 of NTX. In ABZ.SO, hatching occurred only at 0.00038, 0.0007, and 0.0015 μmol L-1 concentrations. The obtained DDs of 0.043 μmol L^-1 for NTX and 0.00099 μmol L^-1 for ABZ.SO can be used to monitor efficacy in field isolates.

The flea Ctenocephalides felis felis and the tick Rhipicephalus sanguineus are ectoparasites of great importance in veterinary medicine that can affect pets, also impacting the lives of owners due to the possible transmission of zoonoses. Due to the negative impact on animals, owners and the environment, synthetic chemicals are being replaced by natural alternatives. Eugenol and carvacrol stand out as bioactive substances with potential antiparasitic activity. The aim of the present study was to develop and characterize physicochemically spray and spot-on formulations containing bioactives alone and in combination and to evaluate their ectoparasiticidal activity through in vitro bioassays of the knockdown effect and residual efficacy against adult fleas and ticks. Regarding flea knockdown, spot-on formulations achieved maximum mortality in a shorter period than spray formulations, 2 h for carvacrol plus eugenol (SCE) and 4 h for carvacrol (SC) and eugenol (SE) alone, compared to 15, 30 and 45 min for the spot-on formulations of carvacrol (PC), both substances together (PCE) and eugenol alone (PE), respectively. For tick control, the formulations required longer exposure times than for fleas, so that 100% control took 6 h for PCE, followed by 12 h for SCE and PE, and 24 h for PC, SC and PE. Regarding residual efficacy against fleas, the spray and spot-on formulations remained active for approximately 90 and 45 days, respectively. In general, formulations containing associated bioactives had a faster knockdown effect than formulations with only one in their composition, indicating a synergistic effect of the two bioactive substances against fleas and ticks.

This study presents a comprehensive methodology for the synthesis, characterization, and evaluation of selenium nanoparticles (SeNPs) for their anthelmintic properties against Trichinella spiralis. SeNPs were synthesized via a chemical reduction method, with a color change from clear white to brownish-red indicating nanoparticle formation. X-ray diffraction (XRD) analysis revealed broad peaks at 2θ ranges of 20-33° and 48-58°, confirming the semi-crystalline nature of the nanoparticles. UV-Vis absorption spectroscopy identified a characteristic peak at around 295 nm. High-resolution transmission electron microscopy (HRTEM) showed spherical, monodispersed SeNPs with smooth surfaces, ranging from 30 to 106 nm in size, with an average diameter of 69 nm. Forty-two male rats were divided into six groups, including healthy controls and T. spiralis-infected rats treated with varying doses of SeNPs. Body and organ weight indexes were assessed at the start, during the intestinal and muscular phases. Significant body weight increases were observed during the intestinal phase, particularly in the positive control group. Organ weight analysis showed a significant decrease in liver weight in the high-dose SeNP group compared to controls. SeNP treatment significantly reduced the number of adult worms in the intestines and encysted larvae in muscles. The high-dose group reduced adult worms and encysted larvae more than the low-dose group. Scanning electron microscopy (SEM) revealed morphological alterations in adult T. spiralis worms, including wrinkled architecture, torn cuticles, and severe sloughing in high-dose treated worms. During the muscular phase, significant decreases in hemoglobin and red blood cell count were observed in the positive control group, while SeNP treatment restored these levels. Liver enzyme activities (AST, ALT, and ALP) were elevated in infected untreated groups but were enhanced with SeNP treatment. Antioxidant enzyme activities (CAT, and SOD) increased in SeNP-treated groups, with higher doses showing greater efficacy in reducing oxidative stress markers (MDA) and inflammatory markers (TNF-α, and IL-6). Histological analysis showed significant restoration of normal intestinal architecture in high-dose SeNP-treated infected rats, including the reduction of villus atrophy and leukocyte infiltration. In diaphragm muscles, high-dose SeNP treatment minimized encysted larval deposition and restored normal muscle architecture. We can conclude that the study demonstrates the potential of SeNPs as an effective anthelmintic agent against T. spiralis, highlighting their synthesis, characterization, and therapeutic efficacy.

Faecal samples were obtained from 77 first season grazers from 20 Norwegian dairy herds in autumn 2020 for analysis of Cooperia oncophora and Ostertagia ostertagi infection. Strongylid eggs per gram of faeces (EPG) were determined for each sample and the samples underwent larval culture. DNA was extracted from the faeces at different stages of the culture preparation: from faecal slurry (FS), direct extraction before culture (DBC), and direct extraction after culture (DAC). Extracted DNA was subject to molecular assay for both C. oncophora and O. ostertagi using both a published ddPCR assay and a modified qPCR duplex assay targeting the ITS-2 gene. For C. oncophora, DBC samples contained significantly less ITS-2 copies than DAC and FS samples (p ≤ 0.0001 for both) for qPCR, but not between DAC and FS samples (p = 0.339). Droplet digital PCR with DBC samples yielded significantly fewer ITS-2 copies than DAC and FS samples (p ≤ 0.0001). For O. ostertagi, the ITS-2 copies in DBC samples differed significantly from levels in DAC and FS samples on the qPCR platform (p=0.002 and 0.044, respectively) as was the case with ddPCR (p ≤ 0.0001 and 0.0137). Overall, across the various processing techniques, C. oncophora results obtained on both ddPCR and qPCR platforms correlated with EPG better than was found for equivalent results for O. ostertagi and results are strongly indicative of poor correlation when EPG counts are low. Results from this study suggest that DAC faecal processing was of limited practical use.

The cattle tick Rhipicephalus microplus is prevalent in tropical and subtropical regions, causing substantial economic losses due to its resistance to conventional acaricides. There is an urgent need to identify safe and effective new acaricidal agents. Essential oils and their volatile compounds are promising alternatives. Ensuring the use of optimal solvents or surfactants that do not compromise the acaricidal activity of these compounds during testing is crucial. This study aims to evaluate how compounds thymol, carvacrol and eugenol interact with xylol, methanol, ethanol, acetone, isopropyl alcohol, glycerol, dimethyl sulfoxide, castor oil, propylene glycol, vaseline, and Tween 80® to enhance (or to worse) their acaricidal efficacy against R. microplus. Larval mortality time were compared against one negative control (soybean oil) and two positive controls (commercial pour-on products). The experiments were conducted in 48-well polyethylene plates, with around 100 larvae immersed in 200 μl of each solvent at 100, 50, 25, 12.5, 6.25, 3.125 and 1.56% and diluted in soybean oil or water, according to solubility. Each volatile compound (Thymol, carvacrol and eugenol) was diluted in the tested solvents to assess larval mortality time. Xylol demonstrated the shortest larval mortality time, even at a minimum concentration (p < 0.05). In contrast, liquid vaseline exhibited the longest larval mortality time. When thymol, carvacrol, and eugenol were combined with xylol, they achieved the shortest larval mortality time. Conversely, when diluted in liquid vaseline they exhibited synergistic effects decreasing the mortality time. Tween 80® worsen the efficacy of thymol, carvacrol, and eugenol, resulting in prolonged larval mortality times. These findings emphasize the critical role of solvent selection, indicating the choice of solvent profoundly affects the formulation's effectiveness, directly influencing the activity of the active compounds.

Ticks vector a large number of significant pathogens, yet remain understudied due to the challenges in laboratory colonization. This study introduces innovative techniques for rearing Rhipicephalus sanguineus, focusing on in vivo tick feeding using ICR mice (Mus musculus) as a blood source. The research, conducted at the Walter Reed Army Institute of Research - Armed Forces Research Institute of Medical Sciences (WRAIR-AFRIMS), outlines the successful utilization of mice to support all stages of tick development. Ticks were retained on mice using Ethylene-Vinyl Acetate (EVA) foam capsules and cyclophosphamide was administered to the mice to prevent host immune response from interfering with tick feeding. These methods allowed the successful establishment and mass production of R. sanguineus tick colonies. The methods described herein hold promise for institutions seeking efficient tick production using a rodent model.

An active immunoproteome of Trichomonas vaginalis was obtained by 2D-Western blotting (2D-WB). Subsequent proteoform identification by mass spectrometry (MS) showed differential expression and specific immunoreactions of multiple proteins mediated by the presence of Zn²⁺. A total of 25 proteoforms were immunologically reactive, generally under Zn²⁺ conditions, and MS analysis revealed that the fimbrin (plastin) of T. vaginalis (TvFim1) was recognized by the sera of male patients with trichomoniasis but not by the sera of infected female patients. These findings suggest that the protein is immunogenic during active male trichomoniasis and that cytoskeletal proteins, including fimbrins, may also act as virulence factors in addition to their role in parasite morphogenesis.